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A CHEMIST LOOKS AT COAL PETROGRAPHY

VIEWS: 35 PAGES: 153

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\                                          A Chemist Looks a t Coal P e t r o l o g y

                                                             P. H. Given

                                              Department of F u e l Technology
                                              Pennsylvania S t a t e U n i v e r s i t y
                                                U n i v e r s i t y Park, P a .

               P e t r o l o g y i s i n g e n e r a l d e f i n e d as t h e s t u d y of r o c k s , and i s c o n s i d e r e d a
    branch o f geology. I n t h e s t u d y of i n o r g a n i c r o c k s t h e p e t r o l o g i s t r e l i e s h e a v i l y
    f o r i d e n t i f i c a t i o n of m i n e r a l s p e c i e s on such o p t i c a l p r o p e r t i e s a s r e f r a c t i v e
1   index and b i r e f r i n g e n c e , and o n c h a r a c t e r i s t i c c r y s t a l form o r morphology. The
    c o a l p e t r o l o g i s t also r e l i e s on o p t i c a l p r o p e r t i e s t o d i s t i n g u i s h "macerals" i n
    t h e o r g a n i c rock, c o a l , b u t h a s t o u s e r e f l e c t a n c e o r c o l o r i n t r a n s m i t t e d l i g h t
    r a t h e r t h a n r e f r a c t i v e index, and cannot d e r i v e h e l p from c r y s t a l form. I n s t e a d
    he has t o study t h e palaeobotany of t h e sample and make what u s e he c a n of d i f -
    f e r e n c e s i n b o t a n i c a l s t r u c t u r e or o f t y p e s of a s s o c i a t i o n of d i f f e r e n t l y shaped
    b o d i e s i n a sample; i t i s t h i s d i f f e r e n c e from i n o r g a n i c p e t r o g r a p h y t h a t g i v e s t h e
    s t u d y of c o a l i t s p e c u l i a r d i f f i c u l t y .

                The nomenclature and c l a s s i f i c a t i o n o f t h e e n t i t i e s d i s c e r n e d i n c o a l s by
    p e t r o l o g i s t s i s a complicated matter which h a s been p r o d u c t i v e o f much c o n t r o v e r s y ,
    and there i s s t i l l no u n i v e r s a l l y a c c e p t e d system. Consequently i t i s n o t easy f o r
    o t h e r workers i n c o a l s c i e n c e t o g r a s p t h e n a t u r e and s i g n i f i c a n c e of t h e p e t r o l -
    o g i s t ' s work, and they may be tempted t o d i s m i s s t h e work as s t i l l t o o i l l - d e f i n e d
    and c o n t r o v e r s i a l t o be worth basing t h e i r own r e s e a r c h e s on, o r even t o be w o r t h
    f i n d i n g o u t about.

                Such a d i s m i s s a l would be a g r a v e m i s t a k e . It i s t r u e t h a t t h e r e is s t i l l
    l a c k of agreement about t h e s i g n i f i c a n c e of some o f t h e e n t i t i e s claimed t o b e
    p r e s e n t i n c o a l samples, and about t h e i r c l a s s i f i c a t i o n and o r i g i n . N e v e r t h e l e s s ,
    t h e r e i s a body of s o l i d l y e s t a b l i s h e d f a c t which s h o u l d b e t a k e n account of by any
    chemist o r p h y s i c i s t studying coal, and which i s of demonstrable importance even i n
    p r a c t i c a l o p e r a t i o n s f o r t h e u s e o f c o a l . It i s r e g r e t t a b l e t h a t p a p e r s a r e s t i l l
    being p u b l i s h e d i n which o f t e n e x c e l l e n t e x p e r i m e n t a l work i s marred by i n a d e q u a t e
    c h o i c e and d e s c r i p t i o n of samples. Furthermore, i t i s o f t e n f o r g o t t e n t h a t d e s c r i b -
    i n g a c o a l s o l e l y i n terms of one o f t h e v a r i o u s n a t i o n a l t e c h n o l o g i c a l c l a s s i f i -
    c a t i o n systems, such as t h e A.S.T.M.,                   has l i t t l e s c i e n t i f i c v a l u e even t o a worker
    f a m i l i a r w i t h t h e system, and none a t a l l t o workers elsewhere. The systems were
    d e v i s e d t o d e f i n e whole c o a l s f o r t e c h n o l o g i c a l purposes.

                I t i s t h e purpose of t h i s paper t o review b r i e f l y how "macerals"                         come t o be
    p r e s e n t i n c o a l s , and t o d i s c u s s t h e r e l a t i o n between t h o s e a s p e c t s of       contemporary
    c l a s s i f i c a t i o n systems t h a t seem of most importance t o t h e chemist and                          physicist.
    It i s hoped t h a t t h i s w i l l f a c i l i t a t e t h e u s e o f p e t r o l o g i c a l c o n c e p t s   by non-
    petrologists.

               Most major c o a l measures were l a i d down i n e l o n g a t e d d e p r e s s i o n s i n t h e e a r t h ' s
    s u r f a c e known as g e o s y n c l i n e s . For s u b s t a n t i a l d e p o s i t i o n of any k i n d of sediment
    i n a geosyncline, i t i s n e c e s s a r y t h a t t h e r a t e of accumulation of sediment i s a p p r o x i -
    mately balanced by t h e r a t e o f s u b s i d e n c e of t h e f l o o r of t h e d e p r e s s i o n due t o t h e
    i n c r e a s i n g l o a d on i t . V e g e t a t i o n can only t h r i v e and i t s p r o d u c t s o f decay be p r e -
    s e r v e d w h i l e t h e p h y s i c a l c o n d i t i o n s , p a r t i c u l a r l y t h e l e v e l of the water t a b l e
    remain t h i n f a i r l y narrow l i m i t s . S i n c e t h e two r a t e s r e f e r r e d t o above do
                  wi
     remain i n b a l a n c e i n d e f i n i t e l y , a c o r e of t h e m a t e r i a l accumulated i n a g e o s y n c l i n e
                                                                  2

r e v e a l s a f a i r l y r e g u l a r v a r i a t i o n i n t y p e of sediment w i t h depth. Thus t h e c o a l
seams a r e s e p a r a t e d by a r e g u l a r and r e p e a t i n g sequence of i n o r g a n i c sediments, w i t h
f o s s i l s i n d i c a t i n g t h e v a r y i n g d e p t h of t h e water i n which t h e sediment was t r a n s -
p o r t e d from neighboring h i g h l a n d and t h e n d e p o s i t e d .

            Even during t h e f o r m a t i o n of one c o a l seam, c o n d i t i o n s vary. Varying water
l e v e l and movement changes the d e g r e e of a e r a t i o n and hence t h e a c t i v i t y of a e r o b i c
b a c t e r i a i n b r i n g i n g about decay. The d i f f e r e n t t y p e s of chemical s u b s t a n c e p r e s e n t
i n p l a n t s - c e l l u l o s e , l i g n i n , r e s i n s , waxes, t a n n i n s , e t c . - a r e p r e s e n t i n d i f -
f e r e n t r e l a t i v e p r o p o r t i o n s i n l i v i n g woody t i s s u e , i n dead c o r t i c a l t i s s u e , i n s e e d
and l e a f c o a t i n g s , and s o on; and a l s o t h e s e s u b s t a n c e s show d i f f e r i n g d e g r e e s of
r e s i s t a n c e t o decay. I t can t h e r e f o r e be s e e n t h a t as c o n d i t i o n s f l u c t u a t e d u r i n g
t h e accumulation o f p l a n t d e b r i s , t h e b o t a n i c a l n a t u r e and chemical composition of
t h e m a t e r i a l s u r v i v i n g complete breakdown w i l l f l u c t u a t e also. This f l u c t u a t i o n is
t h e o r i g i n o f t h e f a m i l i a r banded s t r u c t u r e of c o a l seams, which i s v i s i b l e to t h e
naked eye, and i t p r o v i d e s a prima f a c i e case f o r supposing t h a t t h e banded c o n s t i t u -
e n t s w i l l d i f f e r c h e m i c a l l y and p h y s i c a l l y .

            There i s another d e d u c t i o n t o be made from t h e mode of o r i g i n o f t h e banded con-
s t i t u e n t s . The average n i t r o g e n c o n t e n t o f c o a l s is a p p r e c i a b l y more t h a n t h a t of
p l a n t s , and i t i s commonly supposed t h a t t h e extra n i t r o g e n o r i g i n a t e s from t h e
p r o t e i n c o n t e n t of t h e b a c t e r i a t h a t brought about decay i n t h e p e a t swamp, the bac-
t e r i a l remains having been i n c l u d e d i n t h e c o a l s t r u c t u r e . Varying n i t r o g e n c o n t e n t s
i n c o a l s t h e r e f o r e r e f l e c t v a r y i n g amounts of metamorphosed p r o t e i n mixed i n w i t h t h e
plant debris.

           The c h a r a c t e r of t h e biochemical system and of t h e p h y s i c a l c o n d i t i o n s was
never such as t o p r e s e r v e o n l y one k i n d of p l a n t d e b r i s t o t h e e x c l u s i o n of o t h e r s .
Consequently t h e banded c o n s t i t u e n t s a r e merely c o n c e n t r a t e s of some more fundamental
components. The European c l a s s i f i c a t i o n of t h e s e components i n t o m a t e r i a l d e r i v e d
from woody t i s s u e ( v i t r i n i t e ) , from s p o r e s , s e e d c o a t i n g s , c u t i c l e s , e t c . ( e x i n i t e ) ,
from woody t i s s u e c a r b o n i z e d o r changed i n some o t h e r way t o " n a t u r a l c h a r c o a l " ( f u s i -
n i t e ) , and from an unknown source, p o s s i b l y humic mud (micrinite), i s t o o w e l l known
t o need d i s c u s s i o n h e r e (see, f o r example, Van Krevelenl, Brown2).                            The s i g n i f i c a n c e
of t h i s b a s i c c l a s s i f i c a t i o n h a s been confirmed by chemical, c a r b o n i z a t i o n , and o t h e r
s t u d i e s ( s e e Given3 and r e f e r e n c e s t h e r e i n ) .

            European and o t h e r p e t r o l o g i s t s have b e l i e v e d f o r some time t h a t t h e f o u r main
c a t e g o r i e s are themselves n o t fundamental, and r e s e a r c h on proper s u b - d i v i s i o n and
c l a s s i f i c a t i o n c o n t i n u e s a c t i v e l y . No doubt i n t i m e p u r i f i e d samples of t h e sub-
components w i l l become a v a i l a b l e f o r f u r t h e r s t u d y by o t h e r t e c h n i q u e s . So f a r no
a t t e m p t h a s been m a d e t o s u b s t a n t i a t e p h y s i c a l l y and chemically t h e p e t r o l o g i c a l
d i s t i n c t i o n between t e l l i n i t e and c o l l i n i t e (forms of v i t r i n i t e w i t h and w i t h o u t
cellular structure respectively).                               Of t h e v a r i o u s members of t h e e x i n i t e group, o n l y
s p o r i n i t e (from megaspores) h a s r e c e i v e d any e x t e n s i v e chemical s t u d y .

           In t h e chemical and p h y s i c a l s t u d y of c o a l s i t i s customary t o c o r r e l a t e , f o r
a series of samples, t h e p r o p e r t y being measured w i t h some o t h e r p r o p e r t y presumed
t o measure rank. Even w i t h p u r e v i t r i n i t e s t h e r e i s a p p r e c i a b l e s c a t t e r i n any p l o t ;
t h e r e i s much s c a t t e r w i t h s p o r e - r i c h e x i n i t e s ; w h i l e w i t h f u s i n i t e s t h e concept of
rank seems t o break down a l t o g e t h e r s i n c e no rank parameter g i v e s any c o r r e l a t i o n .
The s c a t t e r may be due t o t h e i n c o r r e c t c h o i c e of rank parameter (on t h i s , s e e below)
o r t o t h e random o p e r a t i o n of n a t u r e i n t h e metamorphic p r o c e s s . However, t h e s c a t -
t e r may a l s o be taken to i n d i c a t e t h a t t h e materials a r e s t i l l heterogeneous, and
that t h e p e t r o l o g i s t s a r e c o r r e c t i n i n s i s t i n g on f u r t h e r s u b - d i v i s i o n of t h e c l a s -
s i f i c a t i o n referred to.

        The European maceral c o n c e p t has been c r i t i c i z e d by American p e t r o l o g i s t s on
 t h e grounds t h a t i t t a k e s no account o f rank.   I n t h e a u t h o r ' s view t h i s c r i t i c i s m
                                                                     3
is based on a misconception. C l e a r l y t h e fundamental p o i n t i s t h a t t o d e f i n e a p u r e
sample completely, a t l e a s t t w o s t a t e m e n t s are necessary: one showing t h e maceral
group t o which t h e specimen must be assigned, and t h e o t h e r l o c a t i n g t h e p o i n t i n t h e
sequence o f changes from p l a n t m a t e r i a l t o g r a p h i t e (or g r a p h i t i c carbon) reached by
metamorphosia. This p o i n t can be i n d i c a t e d i n a number of ways, of which t h e com-
monest are t h e use of carbon content, y i e l d i n t h e s t a n d a r d v o l a t i l e m a t t e r test, and
maximum r e f l e c t a n c e under o i l immersion.

           European workers (and chemists elsewhere) most commonly d e f i n e rank by means of
t h e carbon c o n t e n t (d.a.f. o r d.m.m.f.)               of t h e sample o r i n t h e c a s e o f f u s i n i t e by
t h e carbon c o n t e n t o f t h e a s s o c i a t e d v i t r i n i t e . S i n c e metamorphosis i s e s s e n t i a l l y
a chemical process, and i t s t r e n d i s towards pure carbon, t h e c a r b o n c o n t e n t a p p e a r s
t o t h e a u t h o r t o be t h e b e s t a v a i l a b l e and most n e a r l y d i r e c t measure of rank. How-
ever, i t must b e a d m i t t e d t h a t i f r e f l e c t a n c e is used as a measure o f rank, t h e same
s e t of microscopic o b s e r v a t i o n s can b e used b o t h t o i d e n t i f y the m a c e r a l group and
a s s i g n a specimen t o i t s p l a c e i n t h e group; use of t h e carbon c o n t e n t r e q u i r e s a
s e p a r a t e observation.

           I n r e c e n t years, a number of new i d e a s have been i n t r o d u c e d i n t o c o a l p e t r o l o g y
by American workers, which i n v o l v e a c o n s i d e r a b l e amount of r e - d e f i n i t i o n of c o n c e p t s .
Groups of workers a t Pennsylvania S t a t e U n i v e r s i t y , t h e U. S . S t e e l Corporation, t h e
I l l i n o i s G e o l o g i c a l Survey and o t h e r c e n t r e s have been a c t i v e i n f o r m u l a t i n g t h e s e
ideas, which however have n o t y e t been made widely a v a i l a b l e to c h e m i s t s .

            Spackman, Berry and t h e i r co-workers4 have made e x t e n s i v e m i c r o s c o p i c s t u d i e s
of c o a l s by t r a n s m i s s i o n of l i g h t through t h i n s e c t i o n s . They observed t h a t t h e
m a t e r i a l d e r i v e d from woody t i s s u e ( v i t r i n i t e ) commonly c o n t a i n e d f a i r l y w e l l - d e f i n e d
r e g i o n s o f d i f f e r e n t c o l o r , some of which showed remains o f c e l l u l a r s t r u c t u r e and
some d i d not.             I n a s u i t e of samples covering a wide range of r a n k t h e y observed
r e g i o n s o f c o l o r ranging from b r i g h t yellow through orange, r e d and deep r e d t o an
almost opaque red-brown.                      I n any one sample t h e r e were n o t more t h a n two o r t h r e e
predominating c o l o r s , and i n g e n e r a l t h e c o l o r s h i f t e d a c r o s s t h e s p e c t r u m towards
r e d as t h e rank of t h e sample i n c r e a s e d . They f e l t t h a t i n a series of samples n i n e
d i f f e r e n t shades of c o l o r c o u l d be r e p r o d u c i b l y d i s t i n g u i s h e d , and termed t h e compo-
n e n t s of d i f f e r e n t c o l o r v i t r i n o i d s . The v i t r i n i t e from a low-rank bituminous c o a l
might t h e r e f o r e be composed on t h e i r h y p o t h e s i s predominantly o f v i t r i n o i d s 2 and 3,
a medium-rank o f v i t r i n o i d s 4 and 5, and so on. Two v i t r i n i t i c c o a l s o f s i m i l a r rank
might d i f f e r c h i e f l y i n t h e r e l a t i v e p r o p o r t i o n s of t h e same v i t r i n o i d s .        By s p e c i -
f y i n g t h e v i t r i n o i d a n a l y s i s o f a sample, t h e r e f o r e , they were d e f i n i n g b o t h t h e
maceral group and t h e rank from t h e same s e t of o b s e r v a t i o n s .                         However, there is one
r e s e r v a t i o n : i n c e r t a i n c a s e s i t is d i f f i c u l t t o d i s t i n g u i s h a h i g h - r a n k v i t r i n o i d
from a s e m i - f u s i n i t e ; t h i s p o i n t i s d i s c u s s e d below.

            Some c o n f i r m a t i o n t h a t t h e v i t r i n o i d s d i f f e r i n some s i g n i f i c a n t manner w a s
o b t a i n e d from c o l o r cinematography of samples mounted on t h e h o t - s t a g e o f a m i c r o -
scope; i n t h i s way d i f f e r i n g behavior - melting, swelling, change o f c o l o r , e t c .                                 -
of t h e v a r i o u s components c o u l d be observed d i r e c t l y . F u r t h e r e v i d e n c e of t h e s i g -
n i f i c a n c e of t h i s v i t r i n o i d concept w a s o b t a i n e d as a r e s u l t o f t h e p r e p a r a t i o n o f
pure v i t r i n o i d s by c a r e f u l micro-manipulative t e c h n i q u e s a p p l i e d t o s e l e c t e d samples.
I n a s e r i e s o f experiments, t h e p u r e v i t r i n o i d s were c a r b o n i z e d i n m i x t u r e w i t h
v a r i o u s p r o p o r t i o n s o f i n e r t f i l l e r (fused alumina), and t h e h a r d n e s s o f t h e coke was
t h e n measured. It w a s found t h a t t h e curve o b t a i n e d by p l o t t i n g coke h a r d n e s s
a g a i n s t p r o p o r t i o n o f i n e r t had a c h a r a c t e r i s t i c shape f o r e a c h v i t r i n o i d , t h e shape
of t h e curve being r e p r o d u c i b l e w i t h samples of t h e same v i t r i n o i d s e p a r a t e d from
d i f f e r e n t coals.

            The h y p o t h e s i s of Spackman and Berry and t h e i r s u p p o r t i n g e v i d e n c e a t l e a s t
e s t a b l i s h a c a s e f o r t h e h e t e r o g e n e i t y of v i t r i n i t e s which is worthy of f u r t h e r
 investigation.             The h y p o t h e s i s i s e a s i l y comprehended i n chemical terms, and i t
 s h o u l d n o t be d i f f i c u l t t o d e v i s e experiments f o r t e s t i n g i t p r o v i d e d s u f f i c i e n t l y
                                                                                4
s e n s i t i v e p h y s i c a l and chemical methods a r e a v a i l a b l e . On t h e o t h e r hand, i t i s n o t
easy t o s e e how any p r o b a b l e combination of biochemical and g e o l o g i c a l c o n d i t i o n s
c o u l d have produced s u c h a s t r i c t l y l i m i t e d number of fundamental c o n s t i t u e n t s of
which a l l v i t r i n i t i c c o a l s are t o be presumed t o be composed. Moreover, s i n c e t h e
a b s o r p t i o n of l i g h t by c o a l s i n u n s e l e c t i v e , t h a t i s , not i n w e l l - d e f i n e d bands,
d i v i s i o n i n t o m a t e r i a l s o f c o l o r shade d i s t i n g u i s h a b l e by eye has an element of
arbitrariness.

            Because of t h e n e c e s s a r y l a c k o f o b j e c t i v i t y i n s e p a r a t i n g m a t e r i a l s according
t o t h e i r c o l o r i n t r a n s m i t t e d l i g h t , c u r r e n t p e t r o l o g i c a l r e s e a r c h i s p l a c i n g more
emphasis on t h e u s e o f r e f l e c t a n c e measurements. A d e t a i l e d system of c l a s s i f i c a t i o n
o f c o a l components based on r e f l e c t a n c e has now won g e n e r a l acceptance among p e t r o l -
o g i s t s i n t h i s country ( s e e S c h a p i r o and Gray5). I n t h i s system, the observed range
o f r e f l e c t a n c e v a l u e s o f v i t r i n i t i c m a t e r i a l s i n o i l i s d i v i d e d up a r b i t r a r i l y i n t o
s m a l l e r r a n g e s or s t e p s of 0.1% r e f l e c t a n c e , experimental v a l u e s being s i g n i f i c a n t
t o about 0.01%. A component o f v i t r i n i t e having a r e f l e c t a n c e of 0.83%, f o r example,
i s d e s i g n a t e d v i t r i n o i d no.8 o r V8, and one of r e f l e c t a n c e 1.37% i s V 1 3 .                        (Note t h a t
t h e same word v i t r i n o i d i s used as i n B e r r y ' s system, though t h e s i g n i f i c a n c e i s d i f -
f e r e n t ; n o t e a l s o t h a t t h e numbering i n t h e two systems d o e s not correspond a t a l l . )
Other macerals a r e d e s i g n a t e d s i m i l a r l y .             Thus t h e system i n c l u d e s b o t h maceral type
and a n i n d i c a t i o n o f r a n k . The r e f l e c t a n c e of t h e t e c h n i c a l l y important medium t o
low v o l a t i l e v i t r i n i t e s is a good index of rank, and v a r i e s r a p i d l y w i t h carbon
c o n t e n t . The r e f l e c t a n c e of l o w t o medium rank v i t r i n i t e s , however, is low and
v a r i e s o n l y slowly w i t h c a r b o n c o n t e n t . The system has p r a c t i c a l advantages i n
s p e c i f y i n g coking b l e n d s and p r e d i c t i n g c a r b o n i z a t i o n behavior, b u t no fundamental
s i g n i f i c a n c e i s claimed for t h e r e f l e c t a n c e r a n g e s used t o d e f i n e t h e maceral type
number.

            No c o r r e l a t i o n h a s y e t been e s t a b l i s h e d between t h e two " v i t r i n o i d concepts".
According t o t h e F r e s n e l e q u a t i o n , t h e r e f l e c t a n c e of a s u b s t a n c e i s a f u n c t i o n of
t h e r e f r a c t i v e index and t h e a b s o r p t i o n index. In t h e c a s e of medium t o l o w rank
c o a l s , t h e a b s o r p t i o n i n d e x makes a r e l a t i v e l y s m a l l c o n t r i b u t i o n t o t h e r e f l e c t a n c e
of v i s i b l e l i g h t , and t h e l a t t e r p r o p e r t y i s t h e r e f o r e determined mainly by t h e r e -
f r a c t i v e index, which i n t u r n i s r e l a t e d t o t h e d e n s i t y and e l e c t r o n p o l a r i z a b i l i t y
of t h e s u b s t a n c e .        (With h i g h r a n k c o a l s a b s o r p t i o n becomes more i m p o r t a n t . ) Hence
r e f l e c t a n c e and a b s o r p t i o n measurements o f t e n r e l a t e t o d i f f e r e n t fundamental prop-
e r t i e s . However, i f t h e v i t r i n o i d s d i s t i n g u i s h e d by c o l o r by Spackman and Berry
have fundamental s i g n i f i c a n c e one might expect t h e r e f l e c t a n c e v a l u e s o f a l a r g e
number of p o i n t s on t h e p o l i s h e d s u r f a c e of a s i n g l e block of v i t r i n i t e t o f a l l i n t o
a b i - o r t r i - m o d a l d i s t r i b u t i o n c u r v e . In f a c t a r a n g e of r e f l e c t a n c e v a l u e s a r e
found f o r a s e r i e s of p o i n t s o n a v i t r i n i t e s u r f a c e , but t h e y a r e d i s t r i b u t e d f a i r l y
e v e n l y o v e r t h e range, no s i g n of two o r more peaks being observed as a r u l e . Re-
f l e c t a n c e measurements, i n t h a t a range of v a l u e s i s found f o r one sample, do t h e r e -
f o r e s u p p o r t t o some e x t e n t t h e i d e a t h a t v i t r i n i t e s a r e s t i l l heterogeneous, b u t not
t h a t they are heterogeneous i n the sense suggested by Spackman and Berry.                                                  Some
h i s t o g r a m s i l l u s t r a t i n g t h e s p r e a d of r e f l e c t a n c e v a l u e s found i n v i t r i n i t e s a r e
shown i n F i g . 1.

            There i s one major d i f f i c u l t y common t o a l l systems o f d e t a i l e d c l a s s i f i c a t i o n ;
t h i s a r i s e s from t h e f a c t t h a t there a p p e a r s t o be a completely c o n t i n u o u s g r a d a t i o n
in both c o l o r i n t h i n s e c t i o n and i n r e f l e c t a n c e from high-rank v i t r i n i t e s through
semi-fusinites to fusinites.                        Thus Berry and Spackman f r e q u e n t l y observed r e g i o n s o f
v e r y d a r k - c o l o r e d m a t e r i a l i n predominantly l i g h t - c o l o r e d (low-rank) v i t r i n i t e ; one
can e i t h e r suppose t h i s m a t e r i a l t o r e s u l t i n t h e p e a t swamp from the same k i n d o f
b i o c h e m i c a l p r o c e s s t h a t l e d t o t h e f o r m a t i o n o f v i t r i n i t e s but more severe, o r t h a t
i t is a p r o d u c t of t h e same p r o c e s s t h a t produced f u s i n i t e , again a t t h e p e a t s t a g e .
A t any r a t e t h e d i f f e r e n t i a t i o n o f t h i s m a t e r i a l from t h e r e s t must have o c c u r r e d at
an e a r l y s t a g e of c o a l i f i c a t i o n and n o t d u r i n g g e o l o g i c a l metamorphism. S i m i l a r
o b s e r v a t i o n s t o t h e above a r e made i n r e f l e c t a n c e s t u d i e s at a l l l e v e l s of r a n k .
 C a r b o n i z a t i o n d a t a a r e of no h e l p i n making d i s t i n c t i o n s , s i n c e v i t r i n i t i c m a t e r i a l s
                                                                          5
of v e r y dark c o l o r or of r e f l e c t a n c e i n o i l above about 2.5% are i n e r t , i n t h e s e n s e
t h a t they do n o t s w e l l o r f u s e on h e a t i n g ; i n t h i s r e s p e c t t h e y have t h e same b e h a v i o r
a s s e m i - f u s i n i t e s and f u s i n i t e s . Matters a r e made more d i f f i c u l t by t h e f a c t t h a t
t h e n a t u r e of t h e f u s i n i z a t i o n process is n o t known.

          I t i s c l e a r t h e r e f o r e t h a t i n any a t t e m p t t o i d e n t i f y and group c o r r e c t l y pure
components i n c o a l s t h e r e i s a t p r e s e n t an ambiguity about some s m a l l p a r t of t h e
whole sample; i t could be e i t h e r chemically a k i n t o t h e r e s t of t h e v i t r i n i t e f a m i l y
b u t h i g h l y a l t e r e d , o r i t could be t h e remains of woody t i s s u e t h a t has undergone
some f u s i n i z a t i o n , whatever t h a t may be, and belong chemically w i t h t h e f u s i n i t e
group. I n any c a s e t h e d i s t i n c t i o n becomes b o t h h a r d e r t o make and less important i n
h i g h rank c o a l s .

Summary and Conclusions

            V i t r a i n s may c o n t a i n about 60-95% v i t r i n i t e , t h e b a l a n c e u s u a l l y b e i n g made up
m o s t l y o f f u s i n i t e , s p o r e e x i n i t e and r e s i n i n c l u s i o n s . The r e l a t i v e p r o p o r t i o n s o f
t h e minor c o n s t i t u e n t s v a r y from c o a l t o c o a l .          It i s a l r e a d y e s t a b l i s h e d t h a t such
chemical p r o p e r t i e s a s t h e p r o p o r t i o n o f p h e n o l i c hydroxyl and t h e d i s t r i b u t i o n of
hydrogen i n d i f f e r e n t forms o f combination d i f f e r widely between t h e v a r i o u s maceral
groups.6            I n some c a s e s , where t h e p u r i t y i s h i g h o r t h e e f f e c t s o f i m p u r i t i e s tend
t o c a n c e l one another o u t , an average p r o p e r t y of a v i t r a i n may d i f f e r l i t t l e from
t h a t of t h e pure v i t r i n i t e . I n o t h e r cases t h e r e w i l l be s i g n i f i c a n t d i f f e r e n c e s ; f o r
example, Wyss and Given7 found t h e hydroxyl c o n t e n t o f a series o f v i t r a i n s from
B r i t i s h c o a l s t o r u n c o n s i s t e n t l y lower 10-2o"L of t h e t o t a l c o n t e n t ) t h a n t h e v a l u e s
f o r a s i m i l a r s e r i e s of p u r e v i t r i n i t e s . & Moreover t h e t r e n d of v a l u e s w i t h rank w a s
d i f f e r e n t , and only t h e p u r e v i t r i n i t e s e t of r e s u l t s w a s i n r e a s o n a b l e agreement
w i t h t h e v a l u e s found by Blom                    .
                                                         s 8 f o r a s e r i e s of v i t r i n i t e s from c o n t i n e n t a l
European seams.

          It i s t h e r e f o r e s u b m i t t e d t h a t i n any s c i e n t i f i c i n v e s t i g a t i o n t h e p u r e s t and
most homogeneous m a t e r i a l s a v a i l a b l e s h o u l d always be used. A t p r e s e n t these m a t e r i a l s
w i l l be v i t r i n i t e s o r members of one of t h e o t h e r t h r e e main maceral groups. I t is
n o t d i f f i c u l t t o o b t a i n v i t r i n i t e s a t l e a s t i n good p u r i t y , and t h e p u r i f i c a t i o n h a s
t h e f u r t h e r advantage of e l i m i n a t i n g m o s t of t h e mineral m a t t e r , which g r e a t l y compli-
c a t e s chemical a n a l y s i s i f p r e s e n t i n l a r g e amounts. I f p u r e macerals, i n t h e s e n s e
j u s t d e f i n e d , cannot be used, t h e n a t l e a s t a p e t r o g r a p h i c a n a l y s i s s h o u l d be r e p o r t -
ed.

           I t i s n o t y e t c e r t a i n whether o r how f a r t h e f u r t h e r s u b - d i v i s i o n o f maceral
groups i s j u s t i f i e d on chemical and p h y s i c a l grounds, and i n t e n s i f i e d r e s e a r c h t o
s e t t l e t h i s i s demonstrably worthwhile and h i g h l y d e s i r a b l e .         I n t h e meantime, i t
i s s u g g e s t e d , chemists and p h y s i c i s t s should be aware of c u r r e n t t h i n k i n g o n t h e
subject.

           I n conclusion, t h e a u t h o r would l i k e , w i t h r e s p e c t , t o s u g g e s t t o c o a l p e t r o l -
o g i s t s two u r g e n t needs i n t h e immediate f u t u r e :

          1.    g r e a t e r a t t e n t i o n t o t h e p h y s i c a l s e p a r a t i o n of p u r e components f o r f u r t h e r
                study.

          2.    r e s e a r c h on t h e n a t u r e o f f u s i n i z a t i o n and on t h e v i t r i n i t e - s e m i - f u s i n i t e
                g r a d a t i o n ; i n t h i s , f u l l c o o p e r a t i o n between a l l d i s c i p l i n e s w i l l be
                needed.

                                                            References

1.    D. W . van Krevelen,              "Coal",      Elsevier,        1961.     .
2.    J. K . Brown, B.C.U.R.A.                Monthly B u l l ,       2,1        (1959).
                                                          6
             Given, p r e p r i n t s of Symposium "Recovery, p u r i f i c a t i o n and u t i l i z a t i o n of
3.
                                                                                 .
             c o a l chemicals", Fuel Chemistry D i v i s i o n of Amer Chem. Soc., C i n c i n n a t i ,
             1963, p. 83.

4.   W. Berry, Ph,D. Thesis, The Pennsylvania S t a t e U n i v e r s i t y , 1963.

5.   N. S c h a p i r o and R . J . Gray, Proc. I l l i n o i s Mining I n s t i t u t e , 6 8 t h y e a r , p. 83
             (1960)    .
6.   P. H. Given, M. E . Peover and W. F. Wyss, Fuel,                     3   323 (1960).

7.   W. F. Wyss and P. H. Given, unpublished o b s e r v a t i o n s .

8.   L . Blom, L. Edelhausen and D. W. van Krevelen, Fuel,                     &     135 (1957).




                                                                        Eagle Seam
                                                                        Buchanan Co., Virginia
                                                                         Carbon Content
                                                                          approx. 85% daf
                                                                        M e a n Ro= 1.005%


        a        0.6            0.8               1 .o             1.2
        E
       2    30
       c
        0
        c
        C
        0


       0
        5   20

                                                                         Pittsburgh Seam
                                                                         Brook Co., W . Virginia
            10
                                                                         Carbon Content
                                                                          approx. 82% dof
                                                                         Mean R,=        0.884%
                           I                      I
              0            1      I        1          I       1     1
               0.6          0.8         1 .o       1.2
                       Percent Reflectivity (max.]
                       @ 4851np in O i l (nz1.52)
            DISTRIBUTION OF MAXIMUM REFLECTIVITY OF
                    VlTRlNlTES IN SMALL                            (1/2    inch square)
                           BLOCKS OF BITUMINOUS COAL

                                                      Figure 1
                                                   7



                     A FURTHER STUDY OF THE RELATIONSHIP BMWEEIJ TIG CIIS.TCAL.
     \            PLASTIC, AND PETROGRAPHIC PROPERTIES OF ALABAMA MXDIUI.I-VOL~~TILE
                              COALS AND TBIR CAHBONIZATION BEHAVIOR

                     B. 3. Kuchta, B. Perlic, 3 . J. Gray, and J. D. Clendenin

                                     U. S. Steel Corporation
                                   Applied Research Laboratory
                                        Monroeville, Pa.
I'
                                           Introduction

                   During the past several years, studies have demonstrated that the petro-
         graphic properties of coals an be correlated with their carbonization behavior
         and coking properties       E,5" While coal is being examined petrographically,
                                        )
         a measurement is made of the reflectance of the vitrinite in the crushed coal
         sample. This reflectance has been shown to be directly related to the rank of
         the coal. Furthermore, it is well known that rank is important in the determina-
         tion of other carbonization characteristics such as volume change and coking
         pressure. Since a general relationship prevails between rank and these parameters,
         a correlatio w uld be better if it were confined to a narrow range of coals or
                      g~
         coal blends. 77
I

I!                 In a previous paper6) the authors showed that the volume-change
         characteristics (expansion-contraction in the sole-heated oven) were related to
         the plastic and chemical properties of several Alabama medium-volatile coals.
         In the present paper, the authors demonstrate how not only volume change but also
!        coking pressure are related to the chemical and plastic properties and petrographic
         characteristics of washed coal samples.


                                          Experimental

                   "he samples consisted of a series of six composites of the daily production
         from each of several mines operating in the Pratt, American, and Mary Lee seams
                 )
         (Table I . All samples were taken on consecutive days except for those from Mine B
         in the Pratt seam; the last three samples from this mine were taken six months after
         the first three.

                   For the tests in both the 30-lb pressure-test oven and the sole-heated
         oven, the coals were pulverized to minus 1/4 inch and dried to about 1 percent
         moisture. These conditions were used to obtain more reliable results in these
         small ovens and to permit comparisons with the results of the earlier work.
         oven designs and heating programs have been described in earlier publications?:7~ 8,
         Petrographic, chemical, and plastic properties of the various samples are listed
         in Table I. Corresponding carbonization data are given in Table 11.



         *   See references.
                                                              8

Relation Between Petrographic and Chemical C h a r a c t e r i s t i c s

                  Since r e f l e c t a n c e f u r n i s h e s a r e l a t i v e l y p r e c i s e measurement of rank,’)
t h e amounts of t h e e n t i t y t y p e s p r e s e n t i n t h e c o a l as determined p e t r o g r a p h i c a l l y
should be r e l a t e d t o a chemical-rank parameter, such as v o l a t i l e matter content.
Figure 1 shows t h e r e l a i o n between v o l a t i l e matter content and r e f l e c t a n c e of
t h e e n t i t i e s i n coals.37 I n general, t h e exinoids i n a c o a l contain considerably
more v o l a t i l e matter t h a n t h e v i t r i n o i d s of t h e same rank, and both t h e exinoids
and t h e v i t r i n o i d s contain o r e v o l a t i l e matter t h a n t h e i n e r t semifusinoids,
micrinoids, and f u s i n ~ i d s . ~ This i s i l l u s t r a t e d i n Figure 1, i n which r e f l e c t a n c e
                                                     y
of t h e p r i n c i p a l e n t i t i e s is p l o t t e d a g a i n s t t h e i r v o l a t i l e m a t t e r c o n t e n t s . The
d i f f e r e n t v o l a t i l e m a t t e r c o n t e n t s of t h e e n t i t i e s a r e apparent from t h e l i n e s
connecting e n t i t i e s of t h e same rank. Also one can s e e how t h e d i f f e r e n c e s i n
v o l a t i l e matter c o n t e n t s become l e s s as t h e rank i n c r e a s e s .

                 The average v i t r i n o i d r e f l e c t a n c e c a l c u l a t e d from t h e q u a n t i t a t i v e
p etr o g r a p h i c a n a l y s i s can be used t o c a l c u l a t e t h e v o l a t i l e matter coiitent of
a co a l , by means of t h e following formula developed by Van Krevelen and S c h ~ y e r . ~ )




where VM, i s t h e Jry, a s h -f re e v o l a t i l e m a t t e r content of t h e coal; V&,                        VMTJ, and
VM, t h e dry, ash-free v o l a t i l e m a t t e r contents of t h e e n t i t i e s ; E t h e percentage
of e x i n o i d s and r e s i n o i d s i n t h e c o a l ; V the percentage o f v i t r i n o i d p l u s 113
semifusinoids; and M t h e percentage o f i n e r t e n t i t i e s (micrinoids, fusinoids,
znd 2/3 s e m i f u s i n oi d s ). I n Figure 2 a good c o r r e l a t i o n is apparent between t h e
v o l a t i l e matter from t h e proximate a n a l y s i s and t h a t obtained b y use of t h e above
equation. The c a l c u l a t e d v o l a t i l e m a t t e r s i n Figure 2 are based on t h e use of
t h e e n t i t y v o l a t i l e m a t t e r v a l u e s published by Van Krevelen and Schuyer.3) If
v o l a t i l e matter c o n t e n t s a r e obtained f o r t h e s e e n t i t i e s o f t h e c o a l s being
worked with, even b e t t e r agreement between t h e c a l c u l a t e d values and t h o s e from
t h e proximate a n a l y s i s should be obtained.

Volume-Change C h a r a c t e r i s t i c s

                    Figure 3 shows t h e r e l a t i o n s h i p of t h e maximum f l u i d i t y of t h e s e coals
t o t h e average r e f l e c t a n c e o f t h e v i t r i n o i d s i n them. I n general, a s t h e average
r e f l e c t a n c e of t h e v i t r i n o i d s i n c re a s e s , t h e maximum f l u i d i t y decreases. P r a t t -
seam Mine-B samples e x h i b i t t h e h i g h e s t f l u i d i t y ; Pratt-seam Mine-C and the Mary
Lee-seam samples, i n t e r m e d i a t e f l u i d i t i e s ; and Pratt-seam Mine-A and American-seam
samples, t h e lowest f l u i d i t i e s .

                    Figure 4 shows t h e r e l a t i o n s h i p between t h e volume-change c h a r a c t e r i s t i c s

                                                    e
of t h e s e c o a l s and t h e average r f l e c t a n c e of t h e v i t r i n o i d s p r e s e n t . The volume-
change d a t a have been c o r re c t e d 9 t o a bulk d e n s i t y of 55 lb of d r y c o a l p e r cubic
f o o t . This f i g u r e i n d i c a t e s t h a t t h e c o a l s containing v i t r i n o i d s with r e f l e c t a n c e
oelow about 1 . 1 4 p e r c e n t c o n t r a c t s t r o n g l y , and t h a t t h o s e having v i t r i n o i d
r e f l e c t a n c e above 1 . 1 4 p e rc e n t a r e l e s s c o n t ra c t i n g and show i n c r e a s i n g tendency
toward expansion a s t h e v i t r i n o i d r e f l e c t a n c e i n c r e a s e s . It should be noted t h a t
t h e Mine-; Pratt-seam samples showed t h e widest range i n volume change and a l s o
t h e v i l e s t range i n t o t a l i n e r t s (Table I ) of a l l t h e c o a l s . This range of i n e r t s
shows t h e importance 01 t h e i n e r t content o f a c o a l i n determining i t s volume-change
c h s r e c t e r i s t i c s . 5 ) Tbis i s i l l u s t r a t e d i n Figure 5, i n which t h e volume change of
                                                             9

American-scam c o a l i s p l o t t e d a g a i n s t i t s t o t a l i n e r t content. The samples included.
9 v e r y narrow range of rank and had re fl e c t a n c e s between 1.206 and 1.223 percent.
The t r a n s i t i o n between c o n t r a c t i o n and expansion f a l l s between a t o t a l i n e r t content
of 20 t o 21 percent. Beyond t h i s t h e c o n t r a c t i o n i n c r e a s e s as t h e amount of i n e r t s
in c r e a se s. Evidently t h e "pure" c o a l r e a c t i v e e n t i t i e s could be expected t o be
expanding i n n a t u r e and any i n c r e a s e i n t h e amount of i n e r t s would d i l u t e t h i s
er'fect so t h a t t h e c o a l would be less expanding or even c o n t r a c t i n g . The p a r t i c l e
s i z e of t h e i n e r t s would i n fl u e n c e t h e degree ol t h i s e f f e c t . Conversely, t h e
opposite e f f e c t h a s been noted wherein i f t h e "pure" c o a l r e a c t i v e e n t i t i e s a r e
contracting, t h e a d d i t i o n of i n e r t s r e s u l t s i n less c o n t r a c t i o n . This would be
expected s i n c e t h e i n e r t m a t e ri a l , which shows l i t t l e change i n volume during
carbonization, would d i l u t e t h e c o n t r a c t i n g na t u r e of t h e "pure" c o a l r e a c t i v e s .

                 I n t h e previous study,6) volume changes of t h e c o a l s i n t h e sole-heated
oven were c o r r e l a t e d with t h e i r maximum f l u i d i t i e s . This r e l a t i o n s h i p i s shown
i n Figure 6. The band r e p r e s e n t s t h e range OP v a l u e s noted i n t h e e a r l i e r work,6)
w i t h i n which t h e washed c o a l samples f a l l . This demonstrates t h e u s e f u l n e s s of
t h e G i e s e l e r Plastometer i n a s s a y i n g t h e expansion-contraction p r o p e r t i e s . Here
again, t h o s e c o a l s having a maximum f l u i d i t y above 10,000 d i a l d i v i s i o n s p e r minute
should be c o n t r a c t i n g , and could be expected t o g i v e no d i f f i c u l t y i n t h e pushing
of t h e coke i f operating p r a c t i c e s a r e under c o n t r o l .

                 Figure 7 shows t h e c o r r e l a t i o n between t h e v o l a t i l e m a t t e r content and
t h e volume changes f o r t h e s e c o a l s . Because both v o l a t i l e m a t t e r and r e f l e c t a n c e
are measures of rank, v o l a t i l e m a t t e r would be expected t o y i e l d                  relationship
s i m i l a r t o t h a t obtained i n Figure 4. The a u t h o r s ' e a r l i e r work6T i n d i c a t e s t h a t
a u s e f u l method of e s t i m a t i n g the comparative expansion-contraction c h a r a c t e r i s t i c s
of t h e s e washed c o a l s should r e s u l t from a m u l t i p l e c o r r e l a t i o n with t h e ash along
with t h e v o l a t i l e matter c o n t e n t s . However, because t h e p r e s e n t washed samples
d i d not show enough v a r i a t i o n i n ash content between samples from each mine, a s h
i s not s i g n i f i c a n t i n t h e c o r r e l a t i o n . This does not mean t h a t it should be d i s -
regarded i n c o a l s t h a t show a g r e a t e r degree of v a r i a b i l i t y t h a n 4hese samples had.
Within a narrow range of ash contents, however, i n e r t s a r e important, as shown i n
Figure 5.

Coking Pressure

                   Since both volume change and coking p r e s s u r e appear t o be t h e r e s u l t of
t h e same b a s i c phenomena occurring i n c o a l d u r i n g h e a t i n g , t h e s e two carbonization
c h a r a c t e r i s t i c s would be expected t o c o r r e l a t e under c e r t a i n c o n d i t i o n s . Further-
more, it i s g e n e ra l l y accepted t h a t c o a l s e x h i b i t i n g a coking p r e s s u r e g r e a t e r t h a n
about 2 l b p e r square i n c h or having less t h a n approximately 7 p e r c e n t c o n t r a c t i o n
should not be used.")                     It is not w i t h i n t h e scope of t h i s paper t o judge t h e
v a l i d i t y o f t h e s e l i m i t s . However, i f t h e s e o r any s i m i l a r s e t of l i m i t s a r e used,
th e n some c o a l s w i l l , a t a p a r t i c u l a r o p e r a t in g bulk d e n s i t y , meet one of t h e s e
l i m i t s , b u t not t h e o t h e r . Therefore, it would be d e s i r a b l e i f petrographic,
chemical, or p l a s t i c p r o p e r t i e s of t h e s e c o a l s could be used t o e s t i m a t e t h e coking
p r e s s u r e t h a t might develop.

                 The r e l a t i o n s h i p between coking p re s s u r e of t h e c o a l and average r e f l e c t a n c e
of t h e v i t r i n o i d s i n t h e c o a l i s shown i n Figure 8. The data on t h e Mary Lee-seam
samples are not shown i n t h i s f i g u r e nor i n t h o s e t h a t follow, because t h e s e samples
ha3 higner oven bulk d e n s i t i e s t h a n t h e samples from t h e o t h e r seams. These h i g h e r
b u l k d e n s i t i e s were t h e r e s u l t of t h e c o a rs e r p a r t i c l e - s i z e d i s t r i b u t i o n obtained
i n pulverizin, t h e h i g h e r ash Mary Lee c o a l s , even though t h e y were pulverized t o
                                                                  10

t h e same t o p s i z e as t h e lower ash c o a l s used. I n Figure 8, samples having an
average r e f l e c t a n c e of l e s s t h a n 1.18 percent should n o t e x h i b i t a coking pressure
i n excess of t h e 2 lb p e r square inch u s u a l l y considered a s t h e l i m i t i n g p r e s s u r e
for s a f e oven o p e r a t i o n s .

                 A similar r e l a t i o n s h i p is noted i n Figure 9 between coking p r e s s u r e and
v o l a t i l e matter. I n t h i s f i g u r e , t h o s e c o a l s having a v o l a t i l e m a t t e r g r e a t e r than
28 percent e x h i b i t coking p re s s u re l e s s t h a n t h i s 2-psi l i m i t , and t h e r e f o r e could
be used s a f e l y at t h e b u l k d e n s i t i e s l i s t e d .

                   The r e l a t i o n s h i p between t h e coking p r e s s u r e and t h e maximum f l u i d i t y
is shown i n Figure 10. Those c o a l s having a G i e s e l e r maxim f l u i d i t y i n excess
of 10,000 d i a l d i v i s i o n s p e r minute should not o f f e r any problems with p r e s s u r e i n
                                                                            a
t h e oven. Note t h a t t h i s i s t h e same l i m i t t h a t w s found f o r t h e v o l                -change
c h a r a c t e r i s t i c s . This l e n d s support t o t h e i d e a put f o r t h by P o t t e r l l F h a t t h e s e
car b o n i z a t i o n p r o p e r t i e s could be expected t o c o r r e l a t e under c e r t a i n c o n d i t i o n s .


                                                     Summary

                                                                                      a
                    The c h i e f f i n d i n g of t h i s i n v e s t i g a t i o n w s t h a t r e f l e c t a n c e of t h e
v i t r i n o i d s , v o l a t i l e matter content, and maximum f l u i d i t y can be used t o o b t a i n
an e st i m a t e of t h e expansion-contraction behavior and coking p r e s s u r e e x h i b i t e d
by t h e s e medium-volatile c o a l s . Thus, t h e s e carbonization c h a r a c t e r i s t i c s can be
estimated from t h e parameter most r e a d i l y ' a v a i l a b l e .


                                                   References

1. Schapiro, N., and Gray, R. J., "Petrographic C l a s s i f i c a t i o n Applicable t o Coals
   of All Ranks, " Proceedings of t h e I l l i n o i s Mining I n s t i t u t e , 68th Year,
   PP. 83-97, 1960.

2.                 .
      Schapiro, N , Gray, R. J., and Eusner, G. R., "Recent Development i n C o a l
      Petrography," Blast Furnace, Coke Oven and Raw M a t e r i a l s Proceedings, AIME,
      V O ~ . 20, 1961.


3.    Van Krevelen, D. W., and Schuyer, J . , "Coal Science," E l s e v i e r P u b l i s h i n g Co.,
      Princeton, pp. 232-239 (1957).

4.    Kroger, C., and Pohl, A . , "The P h y s i c a l and Chemical Q u a l i t i e s of t h e S t r u c t u r a l
      C o n st i t u e n t s of t h e Hard Coal (Macerals). I 1 Their Behavior During t h e
                                                             1
      Degasificatior)'Brennstoff-Chemie, Vol. 38, N o . 718, pp. 102-107, A p r i l 1957.

5.    Spaclanan, W., Berry, W. F., Dutcher, R. R., and B r i s s e , A. H., "Coal and Cog1
      Seam Composition as Related t o P r e p a ra t i o n and Carbonization," Presented a t
      Birmingham Regional Technical Meeting of American I r o n and S t e e l I n s t i t u t e ,
      November 30, 1960.

6.    Kuchta, B. R., and Clendenin, J. D., "The Relationship Between t h e Chemical
      and P l a s t i c P r o p e r t i e s of Alabama Medium-Volatile Coals and T h e i r Carbonization
      Behavior," B l a s t Furnace and S t e e l P l a n t , V O ~ . 49, NO. 7 and 8, pp. 766-769.                                *
7.    P r i c e , J. G., Shoenberger, R. W., and P e r l i c , B., "Use of a Thirty-Pound T e s t
      Oven f o r Rapidly Assaying t h e Coking S t r en g t h of C o a l s , " B l a s t Furnace, Coke
      Oven and ~ a M a t e ri a l s Committee Proceedines. AX.
                         v                                            vol. 17. DD. 212-222 (1958).
                                                       11


 8.   Brown, W. T., "Coal B p a n s i o n , " B l a s t Furnace and S t e e l p l a n t , -101. 35,
      January 1942, pp. 67-71, 219-23, 226.

 9.   Naugle, B. W., Wilson, J. E., and Smith, F. W., "Ekpansion ol' Coal i n Sole-
      Heated Oven, " U. s. Bureau of Mines, Report of I n v e s t i g a t i o n s 5295, J a n w r y
      1957.
10. Brisse, A. H., "Determination of Coke Oven P r o d u c t i v i t y from C o a l Charge
    C h a r a c t e r i s t i c s , " Blast Furnace and S t e e l P l a n t , Vol. 4'7, No. 4, A p r i l 1959,
    PP. 376-383.
11. P o t t e r , C. L.,                                            f
                     "The Value of Test Ovens in a Program o Coal and Coke Research,"
      Blast Furnace, Coke Oven and Raw Materials P r o c e e d h g s , AINE, Vol. 1 , 1952.
                                                                                   1


*   I n reference 6 two graphs were reversed and should be c o r r e c t e d as follows:
    t h a t on page 767 should be t i t l e d "Figure 8 . Comparison of S i t e and Zone Samples
    from t h e Mary Lee Seam Mine; " and t h a t on page 768 should be t i t l e d "Figure 7.
    Comparison of S i t e and Zone Samples from American Seam Mine."
Tv! ?? 'T'9
WP-wnlnw
NNNNNN




                                I


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                                I
                                i




r(   N m* M W   , N
                +     m 4 In-
        i
        i




        I




                i
                st!
    I
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            L
                                                               14




                    25 -

                                                        SEMI-FUSINOIDS


                    2.0 -

                s

                     1.5


                                      VlTRlNOlDS

                     1.0

                                  LINES OF
                                 EauAL R N ;
                                        AK '

                    0.5    -                                             EXlNOlDS




                      0                        I                I
                           50              40                  30                   20
                                          VOLATILE MATTER, PERCENT DAF




Figure 1. R e l a t i o n s h i p Between Reflectance and V o l a t i l e Matter




                 w
                 II




                            27       28            29     30        31        32     33   34
                                  CALCULATED VOLATILE MATTER. PERCENT DAF




Figure 2 .   R e l a t i o n s h i p Between Chemically Determinei to1ati;e
             Platter and Tzlculated V o h t i l e Itlatter
\                             26
                              24
                              22
                                                 PRATT MINE A   -0
                              20                 PRATT MINE B   -0
                              18
                                                 PRATT MINE C
                                                 MARY LEE
                                                                -A
                                                                -A
                              16
                                                 AMERICAN       -
                          x
                          2
                              14

                           -
                          > I2

                          2   10
                          Y
                          X


                          a
                          $
                          Y   6




                              4
                                  I0
                                  1    II4       I18
                                         REFLECTANCE R,.   .
                                                           Y


    I   Figure   3.   Relationship Between P l a s t i c i t y and Reflectance




                                       REFLECTANCE R,.     %


         Figure 4.     Relationship Between Volume Change and Reflectance
                                            16




Figure 5.        Relationship o f Volume Change and I n e r t Content




                05        I                                       0
                                                                  1
                              GIESELER MAX F L U I D I T Y , 1000 DDPM

                                                                                           ,

.i g r e   3.    . < e l a t i o n s h i p 3etween Volume Change and P l a s t i c i t y
                                                17




                    20
                                      LEGEND                                               0
                        16 -                                -
                          L


               a?
               0
               W
                    ,-     -
                           -
                               PRATT MINE A
                               PRATT MINE 8 - 0
                               PRATT MINE C - A
                               MARY LEE     - A
                                               0



               5        12-    AMERICAN        H            -                              0

               u
               L                                                                           0
                                                                                                           0

                                                                                                   0
                                                                                           0
                                                                A
                                               'A       '
                                                        A




                         25
                                 1

                                26
                                       1   1

                                           27
                                                ..
                                                . B

                                                    1       1

                                                            28
                                                                     1       1

                                                                             29
                                                                                       1

                                                                                           30
                                                                                               1       1    ,

                                                                                                           31
                                     VOLATILE MATTER, WT %



Figure 7.   Relationship Between Volume Change and V o l a t i l e Matter




                               LEGEND
                          PRATT MINE A              -


               W
               a
                                                                         .. .
               a
               0                                                                 0                 .*
               ;2[!;,.lAy                                        ,       I   ,         I   a,
                                                                                           ,;

                    I


                    0
                    .
                    10
                     1               11
                                      .4                 .8
                                                        11                        1.22                     I 6
                                      REFLECTANCE R,.                            o/.




   Figure 6. Relationship of Coking P r e s s u r e and Reflectance
                                                18




                                                     PRATT MINE A          -
                                                     PRATT MINE B   0      -
                  -
                  v)
                                                     PRATT MINE C - A
                                                     AMERICAN              -               '-   I




                  (3

                                     **        A                                                I
                                                                       a 0
                                                                       0




                       25       26        27         28      29        30        31
                                VOLATILE MATTER, % DRY BASIS




Figure   9.       R e l a t i o n s h i p of Coking Pressure and V o l a t i l e Matter




          5
                                                          PRATT MINE A           -
                                                          PRATT MINE B           -
     g 4                                                  PRATT MINE C           -              I
     W
                                                          MARY LEE               -
     a
     2 3
     n
     l
     W
     a
     P
     (32
     z
     Y
     8    I


          0
              2             4         6        B I O              20        30        50
                       GIESELER MAX F L U I D I T Y , 1000 DDPM




Figure 10. Relationship of Coking Pressure and Plasticity
i                                                            19
     A NEW METHOD, CAPABLE O F AUTOMATION, FOR THE RAPID CLASSIFICATIO:: /JF rlrJLX-
'1       BASED ON THE RELATION O F TOTAL REFLECTANCE POWER T O COKE QlJALITf

                                             R . Busso and B. Alpern

                                      CERCHAR, B.P.           27, C r e i l , France
     Abstract
'i
                  The new method of rapid and automatic c l a s s i f i c a t i o r . o f c o a l s
k    c o n s i s t s i n measuring t h e t o t a l r e f l e c t a n c e power (P.R.C.) Of t h e s u r f a c e
     of a s e r i e s of "n" p e l l e t s formed under s t r o n g p r e s s u r e ar,? wiCiout a
     binder.
!
\
              S t a t i s t i c a l l y , t h e t o t a l r e f l e c t a n c e power v a r i e s l i n e a r l y , i n c r e a s i n g
     with t h e v o l a t i l e matter index between 40 and 20 percent, t h e n decreasing

1    between 20 and 13 percent. The thickness of t h e p e l l e t s i s least around
     V.M. = 25 percent.

                                       V.M. = 2 7 reaches 7; t h e l i m i t of confidence of t h e
                 The r a t i o P . R - G .      04
                                P.R.G. V.M. = 409
      mean P.R.G.,         a t 95 percent, i s about 2 one percent f o r n = 30 pellets.

               A s a t i s f a c t o r y c o r r e l a t i o n between t h e t o t a l r e f l e c t a n c e p a r e r of c o a l
      and t h e q u a l i t y of coke h a s been e s t a b l i s h e d f r o m some p i l o t - p l a n t tests. I n
      standardized conditions o f pn?paration and coking, t h e r e i s a c o r r e l a t i o n by
      type of blend.


                                                    INTRODUCTION

                The r e l a t i o n between t h e petrographic composition o f c o a l s and t h e i r
      coking p r o p e r t i e s has received our a t t e n t i o n for a decade, f i r s t for t h e
      Lorraine f i e l d f r o m which only c o a l having a v o l a t i l e matter index higher
      than 35 percent was mined, then i n t h e North f i e l d where t h e modern tendency
      i s t o l i m i t mining t o a small number of p i t s .

                  The need for automation o f t h e operation o f t h e mine and f o r c o n t r o l
      of t h e washeries and coking p l a n t s l e d us t o s e e k a rapid, p r e c i s e and
      automatic method f o r c l a s s i f i c a t i o n of c o a l s . Thus, after having r e j e c t e d
      t h e t r a d i t i o n a l d e s t r u c t i v e methods based on the behavior of t h e c o a l d u r i n g
      pyrolysis, we experimented with a non-destructive procedure which c o n s i s t s
      i n measuring t h e t o t a l r e f l e c t a n c e power (P.R.G.)      of a s u i t a b l y prepared
      sample.

      I.    Brief Description o f t h e Method (1) ( 2 )

                 The need t o a r r i v e a t an automatic process made it n e c e s s a r y t o abandon
      t h e p o l i s h i n g and t h e s e l e c t i o n of f i e l d s Of v i s i o n o f t h e v i t r i n i t e u s u a l l y
      encountered i n t h e course of measurement o f r e f l e c t a n c e power (P.R.) with
      a microscope.

                   The experimental method consisted i n making, under p r e s s u r e , a
      s e r i e s of p e l l e t s on which t h e t o t a l r e f l e c t a n c e power of t h e s u r f a c e was
      measured with a photometer. A simple v i s u a l examination of t h e pellets
t     thus prepared showed t h a t an important range o f i n t e n s i t i e s of r e f l e c t a n c e
      i s a v a i l a b l e between flaming c o a l s , type 711, and c o a l s c a l l e d "complement"
      ( d ' a p p o i n t ) , type 334,      -
                                          see Figure 1.
J
                                                       20



            4 b r i e f d e s c r i p t i o n o f t h e l a b o r a t o r y equipment a n d of t h e d i f f e r e n t
s t e p s o f t h e method f o l l o w s :

            - After d r y i n g i n a i r ,      t h e coal. i s ground and passed through a
screen     <     i3.Smm.

            -   A p r e s s forms p e l l e t s w i t h a diameter of 25m.                  A pressure of
         D atnospheres i s necessary t o a s s u r e good cohesion without a binder.
The p i s t o n s and counter-pistons are equipped with tungsten carbide p e l l e t s
t o g r e a t l y reduce t h e r a t e o f wear. The s u r f a c e o f t h e upper p i s t o n must
be c a r e f u l l y polished.

            -  The photometer used functions i n t h e following manner: t h e l i g h t
source i s a bulb -6v, 5A- which has a s t a b l e power source. The l i g h t beam
is d i r e c t e d v e r t i c a l l y towards t h e surfac- of t h e ? e l l e t through t h e use
o f a semi-transparent p l a t e . The i n t e n s i t y of t h e r e f l e c t e d l i g h t i s
measured i n t h e same d i r e c t i o n b y means o f a photomultiplier s t a b i l i z e d a t
1,400V.

            -     The i n t e n s i t y of r e f l e c t i o n i s i n d i c a t e d by a micro-ammeter.           Pro-
v i s i o n a l l y , micro-amperes have been adopted as t h e a r b i t r a r y u n i t .

           -       w
                  T o systematic s t a n d a r d i z a t i o n s a s s u r e t h e c a l i b r a t i o n of t o t a l
r e f l e c t a n c e power i n a b s o l u t e values; a standard substance which can be
a r e l a t i v e l y s t a b l e c o a l , s e r v e s t o measure t h e d r i f t due t o wear of t h e
p i s t o n and t o d e t e c t a p o s s i b l e change of t h e compression force, while a
s e r i e s o f g l a s s s t a n d a r d s c o n t r o l s the s t a b i l i t y of t o t a l functioning of
t h e photometer.

            The r e s u l t s discussed i n t h e p r e s e n t paper a r e expressed i n t h e form
of a mean t o t a l r e f l e c t a n c e power i n a r b i t r a r y u n i t s , average of n p e l l e t s
xade a t one time from t h e sane sample                      --
                                                           n = 5, 10, 30, o r 59, a s t h e case
'icy k c --. m : o f a L i m i t o f 'confidence of the mean a t 95 percent may be                                      :I=24
s i n c e t h e d i s p e r s i o n follows a normal law. When n = 30 p e l l e t s t h e r e l a t i v e
t o t a l p r e c i s i o n of measurement o f mean t o t a l r e f l e c t a n c e power i s of t h e
orcer o f I 1 to 1 . 5 p e r c e n t . A a n a l y s i s of v a r i a b i l i t y has shown t h a t a
                                               n
na.jor oar: of t h i s is due t o t h e p r e p a r a t i o n of t h e sample, t h e formation
of I;he p e l l e t s . ana t h e Length of time between t h e completion of t h e formation
of the p e l l e t s an(! the beginninf.; of t h e photometric measurement. The d i s p e r -
s i o n of t h i s l a t t e r i s v e r y s m a l l ,

T?   .   ? a c t o r s inflaencint:     t h e 'Total Reflectance Power

           Tfle p r i n c i p l e of t h e method f o r e s e e s t h a t t h e s t a t e o f t h e s u r f a c e
of t h e p e l l e t viLL depend on t h e preparation o f t h e sample and on t h e forma-
+: 'n
 .o    of t h e p e l l e t s , t h i s dependence varying with t h e p h y s i c a l and chemic61
?rcpeci?s         7   f tiie co.ils.

           1.     ? r e p e r a t i o n of t h e Sanple

                  a.     Yryin::
                                                      21



                              Xxperience has shown t h a t when t h e moisture i n t h e c o a l
    i n c r e a s e s t h e t o t a l .reflectance power i n c r e a s e s , a t f i r s t q u i t e r a p i d l y ,
    :hen :nore slowly a s tile moisture approaches t h a t o f s a t u r a t i o n .

                    b.     nrinding

                           The r e s u l t s obtained with t h r e e d i f f e r e n t degrees o f f i n e n e s s
    100 percent < 1, e 0.5 and                     < 0.2m indicate t h a t the t o t a l reflectance
    power i n c r e a s e s up t o 100 percent < 0. j and t h a t t h e r e i s no advantaGe t o
    grind.inS more f i n e l y ; t h e s e l e c t i v i t y o f t h e method w i l l not be increased
    f o r YrLe p r o s i t y of t h e s u r f a c e is not lessened any more. I n a d d i t i o n ,
    t h i s dqlree o f fineness guarantees t h a t t h e s u r f a c e d i s t r i b u t i o n o f t h e
    macerals w i l l . vary very l i t t l e from one pellet t o another.

                 c. I!omgenization o f t h e ground s a n p l e i s obviously indispensable
    t o assure t h e s t a b i l i t y o f the surface s t m c t u r e o f sll t h e p e l l e t s .

                Beiq: given the importance o f t h e s e t h r e e f a c t o r s , it i s necessary
    t o adopt a reproducible method of p r e p a r a t i o n .

              3.    Formation OF t h e P e l l e t s

                    a.     Dinensions o f the p e l l e t

                            %e diameter mist be chosen a s a f u n c t i o n o f t h e d e s i r e d
    p r e c i s i o n o f measurement 3nd for a 3iven f i n e n e s s of g r i n d i n s . N have  e
    selecteri 25m. The thickness determines t h e mechanical r e s i s t a n c e o f the
    p e l l e t , which i s s u f f i c i e n t a t 41m. By g i v i n g t h e compression c a v i t y of t h e
    matrix a c o n i c a l shape t h e removal of t h e p e l l e t i s made e a s i e r and p e r i p h e r a l
    t e a r i n g i s avoided. Two other secondary c o n s i d e r a t i o n s e n t e r i n t o play: The
    f o r c e of t h e p r e s s must increase as t h e square o f t h e diameter, while the
    q u a n t i t y of :.:ample prepared i s p r o p o r t i o n a l t o t h e t h i c k n e s s .

                    1.
                     ;     Pressure

                      - h e n t h e f o r c e o f compression i s increased, t h e t o t a l r e f l e c -
    tance power increases a t f i r s t r a p i d l y then holdin;: a s y m p t o t i c a l l y towards
    a xaxiiun calue. Above L,OO3 atmospheres t h e t o t a l r e f l e c t a n c e power does
    not vary m p r e c i a b l y . P.e s t a b i l i t y of t h i s pressure can be c o n t r o l l e d
    with t h e heLp of an a p p r o p r i a t e device.

                  c. '!Ae :ie;:ree c f polis!iiny, h e s an important e f f e c t on t?.e va11ie
    c f t::e tot21 reflecteccr: power. n e tungsten c a r b i d e s u r f a c e of t h e p i s t o n
    1s 9olisi;ei w i t : : soye bilI.iarE c l o t h impre:patetf with a diamond p a s t e of
    .Y?lcl: %e incr?asiii;j fineness reaches 3.25.                       Chan:<es i n p o l i s h i n g should be
    e.:sl:iateci 3erioiical1:;,      ei2hher i n d i r e c t l y by deterninin:: t h e t o t a l r e f l e c t a n c e
    m3:ie:f of z s+:a*:::ar:< m a t e r i a l , or d i r e c t l y w i t h an o p t i c a l device.
i
I
              :.    3 o t c m e t r i c ukasurement

                    2.    ?IC    e x i s s i o n s p e c t r a l zone of t h e source



,
                                                   22



                       A f t e r .!laving sought the e x i s t e n c e of abso?-ptiorr ?;ad:, i-. ::.e
r e f l e c t e d beam from 0.25 t o 2 5 ~                               e
                                               without success, w i.a.rc, F o r r ~ : a s r > of ~
momentary convenience, adopted a lamp with a "punctual" fi.1anent v?.ic:. i s
commonly used i n microscopy. This choice i s obviously 1.icked t o ?:a+. of
the photosensitive detector.                                                                                          ' I

                   b. The l i g h t d e t e c t o r must be very s e n s i t i v e since t h e percentat;e
of r e f l e c t e d l i g h t remains below one percent. Our l a b o r a t o r y was equipped
with some very s a t i s f a c t o r y photomultipliers which w e have continued t o ;iork.
with. Their s p e c p a l s e n s i t i v i t y extends from 3,000              1t o '6,500 8. with a
                                                                                                                      I

maximum a t h,200 A.

                   c. Tne t i m e i n t e r v a l between formation o f t h e p e l l e t s and t h e i r
photometric measurement must be constant. The t o t a l r e f l e c t a n c e power o f
t h e s u r f a c e of t h e p e l l e t s f a l l s r a p i d l y during t h e f i r s t two hours and
then becomes s t a b l e . The explanation of t h i s drop i s t h e ob,ject of research.
This condition would b e e a s i l y taken i n t o account with an automatic device.

          4.    The Physical and Chemical P r o p e r t i e s of Coals

                a.    The tendency t o agglomerate without a binder

                           From a b o u t 40 t o 20 percent v o l a t i l e matter, t h e t o t a l r e f l e c -
tance power.increases w i t h rank. (Figure 2, Curve 1) This i n c r e a s e i s due,
on t h e one hand t o t h e i n c r e a s e of r e f l e c t a n c e power of a l l t h e macerals,
on t h e o t h e r hand t o t h e tendency of c o a l s t o o r i e n t perpendicularly t o t h e
compression, which i n c r e a s e s from 40 to 20 p e r c e n t v o l a t i l e matter while t h e
p o r o s i t y of t h e s u r f a c e o f t h e p e l l e t s (measured with a microscope) decreases
from 25 t o 10 percent i n t h e same i n t e r v a l . Below 20 percent v o l a t i l e matter
t h e t o t a l r e f l e c t a n c e power decreases, i n s p i t e of t h e continued i n c r e a s e i n
t h e r e f l e c t a n c e power of t h e macerals, due t o t h e rapid decrease i n t h e
c a p a c i t y t o form p e l l e t s which disappears completely around 13 p e r c e n t
v o l a t i l e matter.         The minimum t h i c k n e s s o f t h e p e l l e t s (Figure 2, Curve 2 )
corresponds t t h e maximum c a p a c i t y t o form p e l l e t s . This m i n i m u m appears
                        o
t o be s l i g h t l y d i s p l a c e d (25 percent v o l a t i l e matter) i n r e l a t i o n t o t h e
maximum t o t a l r e f l e c t a n c e power ( 2 1 percent v o l a t i l e m a t t e r ) .

                     b. P r e s s u r e coupled with r o t a t i o n r e t a r d s t h e decrease i n t o t a l
r e f l e c t a n c e power below 20 percent v o l a t i l e matter b u t does not e l i m i n a t e it.
A f t e r t e s t s , t h i s technique does n o t appear t o be advantageous t o us s i n c e
t h e wear of t h e polished s u r f a c e of t h e p i s t o n i s g r e a t l y a c c e l e r a t e d .

                   C.  The p r o p o r t i o n o f mineral matter, characterized by t h e
amount of ash, w i l l have a v a r i a b l e e f f e c t on the t o t a l r e f l e c t a n c e power
of t h e coals depending on t h e r e s p e c t i v e l e v e l s o f the pure c o a l s and t:?at
of t h e mineral matter. Some systematic experiments have shown t h a t i n t h e
c a s e of s h a l e s o r middlings, f o r which t h e t o t a l r e f l e c t a n c e power i s l i t t l e
d i f f e r e n t from c o a l s of low rank, t h e t o t a l r e f l e c t a n c e power v a r i e s l i t t l e .
Noreover, the amount of a s h of most French c o a l s a f t e r waskink: remains
c o n s t a n t within about one t o two percent. Thus, f o r low coa1.ification c o a l s
i
i


                                                             23



    and even for c o a l s whose v o l a t i l e matter index i s c l o s e t o 7) DercerX,  '
    t h e normal fluctuations i n amount of ash will not n o t i c e a b l y i n f l i e r i c e
    t h e t o t a l r e f l e c t a n c e p o w e r . W have been a b l e t o v e r i P j t h i s e e r e r a l
                                                      e
    times.

               5.    Variations i n t h e Maceral Composition

                        These w i l l r f f e c t t h e t o t a l r e f l e c t a n c e p o w e r t o t h e e x t e n t t h a t
    t h e r e f l e c t a n c e p e r of t h e macerals are very d i f f e r e n t and there i s c e r t a i n l y
    t h e p o s s i b i l i t y of i n t e r f e r e n c e with the c l a s s i f i c a t i o n , which it w i l l be
    proper to examine with care, b u t we do not yet have enough r e s u l t s t o d i s c u s s
    t h i s point.

                      S t i l l , on t h e b a s i s o f petrographic knowledge accumulated both
    a t Cerchar ( 4 ) and i n o t h e r c o u n t r i e s         -
                                                               p a r t i c u l a r l y i n Cennany, Belgium,
    and Holland        -    it i s p o s s i b l e t o foresee t h e d i r e c t i o n of modifications o f
    t h e t o t a l r e f l e c t a n c e power.

                          a. Above a carbon content o f 90-92 p e r c e n t                  -   corresponding t o
    22-23 percent v o l a t i l e m a t t e r        -     t h e t h r e e p r i n c i p l e macerals cannot be
    d i s t i n g u i s h e d by t h e i r t o t a l r e f l e c t a n c e power. It i s t h e r e f o r e p r i n c i p a l l y
    i n t h e c a s e o f c o a l s o f low rank t h a t t h e maceral composition could have a n
    influence. I n f a c t , even f o r a c o a l with 40 percent v o l a t i l e matter t h e
    r e f l e c t a n c e power i n a i r o f v i t r i n i t e i s only s l i g h t l y g r e a t e r t h a n t h a t of
    exinite.

                            The r e f l e c t a n c e power of i n e r t i n i t e on t h e c o n t r a r y is a l r e a d y
    very high. Some important f l u c t u a t i o n s i n the proportion of i n e r t i n i t e could
    p l a y an a p p r e c i a b l e role. P increase i n proportion would b e i n t e r p r e t e d a s
                                                  n
    an e l e v a t i o n i n rank and t h e c o a l would a c t without doubt as i f it were l e a n .

                             This i s v a l i d i n f a c t only f o r                f u s i n i t e , always i n low
    abundance i n our c o a l s , i n comparison with semi-fusinite which, of v a r i a b l e
    r e f l e c t a n c e power, is t h e p r i n i i p l e c o n s t i t u e n t o f t h e i n e r t i n i t e group.

                     d.     The r a t i o s E and        I g e n e r a l l y vary l i t t l e w i t h rank.        When t h e
                                              V          D
    c o a l i s sampled as it l e a v e s a washery which treats a mixture o f many veins
    s i t u a t e d a t d i f f e r e n t l e v e l s , t h e v a r i a t i o n s a r e considerably diminished. This
    w i l l probably no l o n g e r be t r u e i f t h e sampling a p p l i e s to a s i n g l e vein.

    1 1
     1 .     Relation Between t h e Total Reflectance Power and t h e V o l a t i l e r a t t e r
             Index of Coals

                Experirnents with t h e method on s e v e r a l series of c o a l s o f d i f f e r e n t
    o r i & i n s , taken f o r t h e most part from c a r s a r r i v i n g a t a cokery nave provided
    d a t a f o r t h e curve i n Figure 3 which covers t h e e n t i r e ranGe of rank of c o a l s
    used i n coking.

             It is v e r i f i e d t h a t t h e t o t a l r e f l e c t a n c e Dower LOPS f r o m 1 to
                                                                                                    .
    when t h e v o l a t i l e matter index i s reduced by h a l f , t h e t i s , between L3 an?
    23 percent. Below 20 p e r c e n t t h e t o t a l r e f l e c t a n c e power decreases rapid1:J
                                                         24



f o r t!ie reasons a l r e a d y presented i n paragraph II., 45., and can no longer
'he de'ier::iined below- 13 p e r c e n t .       Te
                                                  : h thickness of t h e p e l l e t s varies i n
t h e opposite d i r e c t i o n . The d i s p e r s i o n of d a t a i s due i n p a r t t o t h e f a c t
t h a t a t t h e time of :nakinc t h e measurements, a l r e a d y some t i m e ago, t h e
causes o f d i s p e r s i o n had not a l l been eliminated. The enlargement of
t h e spresd of t h e t o t a l r e f l e c t a n c e power i n comparison t o t h a t much more
1i:nited spread o f t h e r e f l e c t a n c e power of v i t r i n i t e              -
                                                                               which i n t h e same
ranCe v a r i e s o n l y from 9.65 t o 1 . 5             -
                                                       r e s u l t s on the one hand from t h e sum-
mation extended t o a l l t h e rnacerds and on t h e o t h e r hand f r o 3 t h e important
v a r i a t i o n in t h e tendency t o acelomerate under p r e s s u r e , i n o t h e r words,
tiie hardness o f the c o a l s .

              : h t o t a l r e f l e c t a n c e power t h e r e f o r e permits t h e c l a s s i f i c a t i o n of
              Te
r e c e n t l y washed c o a l s eccordin;: t o an o r d e r o f c l a s s i f i c a t i o n very near t o
% h a t which the v o l a t i l e s a t t e r index f u r n i s h e s .

IV.       Rela'iionSetween tiie Total Xeflectance Power and Coking P r o p e r t i e s o f
          Coals and o f Blends

              This :netkoCl o f c l a s s i f i c a t i o n has been t r i e d p r i n c i p a l l y w i t h t h e
i n t e n t i o n of c l a s s i f y i n g d i f f e r e n t c o a l s considered i n d i v i d u a l l y a c c o r d i n s
t o t h e i r ccking p r o p e r t i e s . Tnis o b j e c t i v e could appear t o be utopian
s i n c e a l l of t h e a t t e m p t s made till now have only l e d t o t h e development
of methods indicated below (*) and which rneasure s p e c i f i c a l l y one o r the
o t h e r of two complementary a s p e c t s of these p r o p e r t i e s . The o r d e r o f t h e
methods o f enumeration corresponds t o a decreasing tendency t o p r e s e n t
evidence of t h e s e a s p e c t s :

                  A::dutinatinr: P r o p e r t i e s                           Tendency t o I n t r i n s i c Crackin!;

Swelling i n t h e d i l a t o m e t e r       -   Gray-King Test              Texperature o f r e s o l i d i f i c a t i o n
                                                                                  in the plastometer a t
Roza Index or A i y z u t i n a t i o n I n d i c e s                             v a r i a b l e torque

Crucible Svellini: Index                                                       Coefficient of coctraction a t
                                                                                 t h e temperature of
F l u i d i t y Index i n t h e plastometers                                     resolidification

                                                                               V o l a t i l e : . a t t e r Inciex


                                                                                                                              '
"I'ost o f h ? s e a r e used i n t h e International. C l a s s i f i c a t i o n P r o j e c t which
p e r x i f a definit.ia!: of t h e type c f coal. (5)


             ' : -f?l,lcwin; renarks silouLd be noted :
              ?e

             -    .:
                  "    ,:".s-ci.sticaL r e l a t i o n e x i s t s 3etween t h e v o l a t i l e matter index o r
:?.I:-    qnr!    ;.:e a.:;.:Luti:iatin;; p r o p e r t i e s , which a m zero below 13 percent, increase
9 > j       ..-
         ..>;r    .-. .:;?: a msximuni aro~.in?20 percent, then decrease and become zero
                   -.!TO
above 140 percent. The naximuv. i s explained by the r a p i d i n c r e a s e i n o2
conten-t which, above f i v e percent a t about 28 percent v o l a t i l e matter,
beco:nes s u f f i c i e n t l y abundant t o cause a n e a s i e r degradation of t h e agglu-
t i n a t i n g properties.

            -   Since t h e t o t a l r e f l e c t a n c e power i s due c h i e f l y t o t h e v i t r i n i t e ,
which s e n e r a l l y makes up 50 t o 80 percent o f coals, any v a r i o t i o n i n the
chemical conposition of t h i s w i l l have an e f f e c t on t h e t o t a l r e f l e c t a n c e
power. I n p a r t i c u l a r , s i n c e t h i s maceral contairis t h e major p a r t o f t h e
oxyf;en i n c o a l , an increasir!!; oxygen content w i l l accompany a lowering of
t h e r e f l e c t a n c e power. (**)


(K*) The oxygen of combustion or exothermic oxidation will c e r t a i n l y not
have t h e same e f f e c t on t h e t o t a l r e f l e c t a n c e power.


           I n t h a t which concerns t h e r e l a t i o n between t h e coking p r o p e r t i e s of
blends t e s t e d by d i f f e r e n t methods, of which o w method i s t h e t o t a l r e f l e c -
tance power, and t h e p r i n c i p a l c h a r a c t e r i s t i c s o f t h e cokes* r e s u l t i n g from
t h e s e blends, w b e l i e v e t h a t no general c o r r e l a t i o n e x i s t s ; it w i l l be
                       e
necessary t o e s t a b l i s h t h e r e l a t i o n f o r each type o f blend. 'Phis p r e d i c t i o n
follows from t h e following experimental observations ( 6 ) :


*Independent o f t h e chemical p r o p e r t i e s o f the coke, o f t h e bulk volume and
of t h e Srain d i s t r i b u t i o n , t h e two c h a r a c t e r i s t i c s used by t h e siclerurgic
u s e r are: t h e 1.140 index which measures t h e r e s i s t a n c e t o cracking and t h e
M13 index which measures t h e tendency towards degradation by abrasion.


            -    For a given type o f blend - f o r example, c o a l s 334 and 632                  a      -
r e l a t i o n between t h e M40 and M O i n d i c e s and t h e proportion o f 334 c o a l
e x i s t s . 9s a result, a r e l a t i o n between t h e q u a l i t y o f t h e coke and most
o f t h e cokinc: p r o p e r t i e s of t h e s e blends can be e s t a b l i s h e d . L e t u s note,
however, t h a t the coking p r o p e r t i e s of the c o n s t i b i e n t c o a l s are not a d d i t i v e
s i n c e t h e q u a l i t y o f t h e coke improves r a p i d l y a t t h e beginning when t h e
p r o p o r t i o ? o f c o a l 334 i n c r e a s e s , then more slowly around 30 percent and it
n e a r l y s t a b i l i z e s above 50 t o 60 percent.

              - The l o g i c a l r u l e that p r e d i c t s t h a t t h e c r a c k i n s of t h e coke diminishes
.&en t h e L o l a t i l c matter index of t h e c o a l is lowered i s o n l y v e r i f i e d f o r
t h e types o f mixtures o f c o a l s whose swelling i n t h e d i l a t o m e t e r remains
s u 5 f i c i e n t t o a s s u r e a good ag&lutination and t h e r e f o r e a good cohesion. When
t h i s i s reduced below a c e r t a i n threshold, cracking can i n c r e a s e : t h e M40
i n l e x decreases t , k n becailse crackinp and degradation by a b r a s i o n are increased.
F o r t h e s a w reasons two blends having t h e same v o l a t i l e matter index can
r e s d t i n two cokes of very d i f f e r e n t q u a l i t y .

            - rne presence in t h e blend o f i n e r t substances - mineral m a t t e r                         -
1 ~ .   anticracrinc- constituents           -
                                      coke d u s t              -
                                                       w i l l affect the characteristics of
                                                          26



t h e cokes very d i f f e r e n t l y accordin:: t o t h e i r deeree o f dis-?.r:rmi.C:i: YT.'.
t h e i r proportion.    It i s t h u s t h a t t h e Optixun concentrstion cjf r.',ne p . d ' . c ; "
ground < 0.5m i s not t h e same dependin:< on whether 3 : e !:k t , : e 1 1 ;: n ~ 07          .'                   c : ~

i s considered. I n c e r t a i n cases t h i s concentration car: ke Five ?ercenf ?2:
t h e X l O and ten t o f i f t e e n p e r c e n t f o r the lih0.

          These lengthy g e n e r a l considerations give an i n s i g i ? l i n t o t h e i n m r -
tance and t h e number o f f a c t o r s which intervene t o a l t e r t ? e r e l a t i o n s betweer1
t h e q u a l i t i e s o f c o a l s , . blends, and cokes.

              Fortunately, t h e c o n p l e x i t y of t h e s t u d i e s a r e o f t e n reduced when t n e
o b j e c t i v e o f t h e c l a s s i f i c a t i o n i s l i m i t e d to t h e coking problems i n h e r e n t
i n one c o a l seam or one coking p l a n t ,

              The a p p l i c a t i o n of t h i s method f o r p r e d i c t i n g coking p r o p e r t i e s has
n o t y e t been extended very f a r , W w i l l only mention some systematic
                                                      e
l a b o r a t o r y o r p i l o t p l a n t tests whose reslilts a r e very. encouraging.

          1. V e r i f i c a t i o n o f t h e a d d i t i v i t y of t h e t o t a l r e f l e c t a n c e power
          and a c o r r e l a t i o n w i t h some o t h e r methods Of c l a s s i f i c a t i o n (Laboratory)

                  Two series o f blends were prepared i n t h e l a b o r a t o r y , The f i r s t
was prepared with a base of c o a l 622 t o which c o a l 333 was added i n i n c r e a s i n g
proportions; t h e second contained t h e same base, c o a l 622, t o which c o a l 434
w a s added. As p r e d i c t e d , t h e t o t a l r e f l e c t a n c e power of t h e mixture varied
l i n e a r l y with t h e p r o p o r t i o n o f c o a l o f increased rank and a l s o with t h e
v o l a t i l e matter index o f t h e c o a l s , a t l e a s t up t o 75 percent (Figure 5 . )
.4bove t h a t the l a c k o f p r e c i s i o n o f t h e curve i s due t o t h e small number o f
p e l l e t s measured and t o t h e f a c t t h a t t h i s experiment was c a r r i e d o u t e t t h e
beginning o f t e s t i n g o f t h e method when the causes of d e v i a t i o n uere not a l l
known.

               A t t h e same t i m e a good r e l a t i o n was found between t o t a l r e f l e c -
t a n c e power and swelling i n t h e d i l a t o m e t e r (Figure 5 ) . It was noted t h a t
i n t h e range of low percentages of high rank c o a l where t h e d e v i a t i o n o f
t h e determination o f s w e l l i n g i s q u i t e high, t h e total. r e f l e c t a n c e power could
b e measured with s a t i s f a c t o r y p r e c i s i o n . Now, t a k i n g i n t o account t h e prog-
ress obtained i n the a p p l i c a t i o n o f t h i s method, it i s p o s s i b l e t o d i s t i n g u i s h
two blends whose proportions d i f f e r by only two percent.

           2. Relation between t h e t o t a l r e f l e c t a n c e power and t h e q u a l i t y o f
           cokes obtained with d i f f e r e n t blends. F i r s t p i l o t p l a n t t e s t .

               Tests of t h e s u i t a b i l i t y o f the rnethod have been c a r r i e d o u t i n
e s t a b l i s h i n g t h e r e l a t i o n s between the q u a l i t y o f t h e cokes and t h e t o t a l
r e f l e c t a n c e power o f t h e b l e n d s i n c o l l a b o r a t i o n with t'ne Experimental
S t a t i o n f o r Coking a t Warienau. Table 2 on t h e following pace i n d i c a t e s
t h e composition of t h e blends studied.
i

                                                           27




                                                     m b l e 2.

                                                          Type and Proportion o f Constituent C o a c
    Blends
                                                          333         434           635            622

                                                           30                         70
                                                           25                          ;
                                                                                      7:
    Binary                                                 20                         a0
                                                           10                         90


                                                           13          27                            60
                                                           12          23                            65
J
    Ternary                                                10          20                            70
                                                             6         17                            75


                 These blends ground methodically t o 100 percent < 3mm, have been
    oven d r i e d , H20 = 2$, i n t h e 400 kg oven. For each blend two charges
    were coked under normal conditions. Total r e f l e c t a n c e power was determined
?   on t e n pellets of each of t h e c o n s t i t u e n t s of each blend. The t o t a l . r e f l e c -
    tance power has been c a l c u l a t e d s t a r t i n g from t h a t of t h e c o n s t i t u e n t s , t h u s
    p e r m i t t i n g t h e demonstration of a d d i t i v i t y .

                  Examination of t h e curves i n Figure 6 shows t h a t t h e c a l c u l a t e d total
    r e f l e c t a n c e power, t h e r e f o r e t h e v o l a t i l e matter index o f t h e blend, i s
    r e l a t e d t o t h e r e s i s t a n c e t o cracking of the coke, measured by t h e M40 index,
    on a s i n g l e curve although f o r t h e abrasion capacity, given by t h e M l O index,
    t h e r e i s a curve by type of blend. The M l O index, w e l l r e l a t e d t o t h e d i l a -
    tometer swelling, i s poorly p r e d i c t e d ?)y t h e C r i c i b l e Swelling Index which
    has no s e n s i t i v i t y i n t h e zone of v o l a t i l e matter index between 20 and 33
    percent.

                 The coke q u a l i t y i s l o c a t e d f o r t h e most p a r t i n t h e range o f French
    m e t a l l u r g i c a l cokes f o r which t h e M40 index must be above 78 and t h e Ml.9
    index below 8 - 8.5.

I               The lower l e v e l of cohesion of cokes obtained beginning w i t h t h e
    b i n a r y blends i s e a s i l y explained by t h e excess tendency t o a g g l u t i n a t e o f
    t h i s type o f blend: t h e cokes contain i n c r e a s i n g proportions of f r o t h when
    t h e percentage of c o a l 634 i n c r e a s e s .

              3. Search f o r a r e l a t i o n s h i p between t h e t o t a l r e f l e c t a n c e power
              o f s e v e r a l c o a l s of t h e Lorraine f i e l d and t h e q u a l i t y of t h e cokes.
              Second p i l o t p l a n t t e s t .

                       After t h e encouraiing r e s u l t s reported above it was proper t o
    v e r i f y t h a t t h e method permitted t h e evaLuation of coking p r o p e r t i e s o f
                                                  28



c o a l s of d.ifferent o r i c i n s . The Lorraine f i e l d can f u r n i s h t o s t e e l m i l l
ax:.    .nine coke p l a n t s , f o u r d i f f e r e n t types of c o a l s : 722, 623, 633, 634/635
l i s t e d i n increasint; o r d e r o f ac;glutinatinl; p r o p e r t i e s . The c l a s s i f i c a t i o n
o f these c o a l s wit!; t,he hell, of t o t a l r e f l e c t a n c e power has been t e s t e d i n
t h e case of a moist mixture (H20 = lo$), placed i n an oven a f t e r "tamping"
ail4 whicii contained:

                                   Lorraine c o a l (534 to 722)                72".                                    I



                                   Coal                    J+34                 20.5

                                   AnticrackinG coke breeze                      q',
              '!he c o a l s were ground t o 90 percent < mUn, t h e coke breeze t o
135 percent < 0.5mm.               For each tType of c o a l four charzes were placed i n
t h e b33kg oven. The mean bulk volume of chargin-; was 970kg:/m3. The coking
c o n d i t i o n s corresponded t c those o f t h e Lorraine mining colie p l a n t s . m e
cokes were reTnoved fro:n t h e furnace a f t e r thermal s t a b i l i z a - t i o n was nearly
co:nplete, t h a t i s , when the :niddl.e plane 3f t h e char:;e reached .L,llO°C.

           Ttie b e s t c o r r e l a t i o n s wit11 t h e d i f f e r e n t metnods o f c l a s s i f i c e t i o n
t e s t s a r e assembled i n FiC;urc 7.

             I t i s noted t h a t most o f t!ie c o a l s fall. a l m s a r e p l a r curve for
K40 End       F.il3 when the s b s c i s s a i s t h e measurd t o t a l r e f l e c t a n c e power of
Lorraine c o a l . The cohesion of t h e coke "I<? i s aLso r e l a t e 6 t o t h e d i l a -
t o a e t e r s v e l l i n g and t o t h e icdex of a g g l u t i n a t i o n .

         Although t h e s e r e s u l t s may be again very s a t i s f a c t o r y w f e e l t h a t a
                                                                                     e
more rigorous v e r i f i c a t i o n covering a much wider rande o f q u a l i t y and a very
much l a r g e r nunker of samples i s necessary before passin: a d e f i n i t i v e ,jucSe-
ment on t h e v a h e of t h e nethod.

                  t h i r d series of p . i l o t p l a n t experiments now mderway w i l l permit
s t a t i s t i c a l conparison o.f the d i f f e r e n t methods of c l a s s i f i c a t i o n which we
al.so c c n s i 2 e r a s v a l i d 5ut for whick auto:r,ation worJd ?:e more difficv3.t.

'I.    Conclusions

          '?le i n t e r e s t . o f this met::od : , r i l l r e s u l t from t h e bal-ance, not y e t
         :
,<e i .ii i ve 1y e s tal:]. i E hed be tweer. i t s po s s i b i 1 1 i e s and it s 1i m i t a t i o c s
    f                                                                    i:
      ~?:e.! i.:i.ti: the performancc of o t h e r methods of c l n s s i f i c a t i o n used i n
      :: n : ~ i which a r e based e i t h e r on t h e behavior o f t h e c c a l i n t h e course
       I
c, f u~:rol.~:;is, o r c:-.           Fetrograaliic iletenninai.ion of rank and maceral
ccx?cs it io:i
         .            .
       I n suwnary: t h e p r i n c i p l e merits of t h e method can be enumerated
eccordine $0 a s c a l e of rank given by t h e volatiLe matter i n d i c e s :

                  a.      +t:ieen 33 arid 4? percent v o l a - t i l e xatter, the t o t a l r e f l e c -
          O,,,
         n - ; . .-        :; statizt.icall-;r i n a l i n e a r manner.
                            :
t


,
                                                        29


i
                  c . 2i.e c l a s s i f i c a t i o n t a k e s i n t o account a t the same time t h e
    !nt.txc silil p r o p c r t i n n s O F t h e mecerals, anJ thus provides a s o r t o f synthesis
    a ? cokin:: p r o p e r t i e s .

                    d . 'The p r e c i s i o n of t h e c l a s s i f i c a t i o n can be very g r e e t f o r
    two m3sons: the s.mmnltion of r e f l e c t a n c e power r e s t s on several. tens of
    ti:o..isz:ncis o f p,o..rticles viiich i n Iar.,e measure e l i m i n a t e s the sa.npl.ing e r r o r :
                                : i ' J i l i t y o f automation it i s easy to i x r e a a e thc n - m ~ r
    of ?Delle t s neasurect ,                  i n s t t k s e advantat;es, one inust note t h e l i m i t s
          a!? 'K?ai;nessea       0"


                 e. %low 13 percent .;olatile m a t t e r the method is no 1on:;er
    aop1ice:rl.c wit'fiout ,aodification vhicti would c o n s i s t of addin;: a kinder.

                      f. From 20 t o 1-3 percent Vie rapi,l decrease ir. tendency t o
    a5;SLoxerate ca;Ises 3 lowerir?g of t i t o t a l r e f l e c t a n c e power. Tiis r e s u l t s
                                                            ie
    i n an arrL,i;:?iiLy -- a t a singLe t o t a l r e f l e c t a n c e pcwer t h e r e a m two d i f f e r e n t
    c o l a t i l e m b t e r icciices. This confusion can be overcome b; measurin;' :
    e i ' c k r t k e t 3 i c k n e s s O F tiie p e l l e t s o r the canpression force of t h e p r e s s .

                      ,.I. hlthoiit:h t h e metho:! i s g e n e r a l l y i n s e n s i t i v e t o t h e proportion
    of n i n e r a l natter o f washed cosl.s, t h e nature of t h e mineral x a t t e r could
    i n c e r t a i n cases cause a s l i g h t s h i f t i n c l d s s i f i c a t i o n .

                       h.      Tne c o a l sample subjected t o t h i s method must be' prepared
    ir, 3 v e r y rcproducio?-e way, however thLs also a p p l i e s t o a l l o t h e r methods
    of c l a s s i f i c a t i o n .

                         i. T i n a l l y , t h e c l a s s i f i c a t i o n by q u a l i t y with t h e h e l p of to-tal
    r e f l e c t a n c e pcwer could be disturbed i n t h e case vttere t h e sampling was
    u r a c t i c e d i n an orid zone o f t h e vein i n which the maceral composition d i f f e r e d
    very m c h from t h e nean composition e s p e c i a l l y as r e l a t e s t.o f u s i n i t e .


              :
              I
              . conclusion:                    A l t h o h t h i s method may be, as t h e a a J o r i t y of o t h e r
                                              "9
    .net:lo.3r: a=,        s u s c e p t i b l e t o probl.ens i n some p a r t i c u l a r cases, ve think t h a t
    i t -<ill apylica'3le t o c l a s s i f i c a t i o n of c o a l s used i n tiie coking p l a n t
                ?:e
    a f t e r so'^ iiiprcvexents which w i l l accompany i t s t r a n s f e r f r o a t h e l a b o r a t o r y
    io i n ! u s t r i a l s c a l e .
                   30


m
     I   ?    '4
         0    0


k;       '9   rl
         r!


0        p:   'u
         cu   m

X
         3
              c9
         3    3

              in
         P;
0        cn
         m
              0
              cn
TYPES    1
        71                                   634                                334




             F i g u r e 1. Appearance of Coal Pellets of D i f f e r e n t Ranks
                                                                    9



                                                                    85



                                                                    6


h
                                                                    zs
s
lu


                                                                    7



                                                                    65
                                                                    7


     Figure 2 .   Relation Between P.R.G. (Curve l), Thickness of
                   P e l l e t s (Curve 2) and Rank
                                33




 ,.
-1,clre 5 . Ciassification and Quality Variation of Some Coals Used
        in Coking ( * e r     1 for Characteristics of Coals)
                                                   34
       .-     . . _.                              ._.-


   PRECISION




RELATirn VALUES
P.R.        VITRIPT’F:

&=3a=017%
  1/50
                           a2
                            0                10              20               30               40




   P.R.G.




V. M. (AFNGR)

&,c30=?%
       v2



              Fig,we La.   Comparison of D i f f e r e n t Metnods of C l a s s i f i c a t i o n
    TEMF'ERAT~           520.
OF WSOLIDIFICATION
      3"/ m N .

     CP39C               480      -
      ( n =3)
                                  -

                F i g u r e 4b.       Comparison of D i f f e r e n t Methods of C l a s s i f i c a t i o n
                                              36




-.
.
I.
     :
       ... c
     L., L "   1   ).   3 i e i a t i o r l 3etween P.R.G. ana tne Ccmposition of Biends ( I ) and
                          tr.e . ; w e A i n g I.n tile Oilatorneter of tile Eiend ( I i )
I    g
     b                                                     37

                                A                      CeRG. = 2 1.5 ( A r b i t r a r y   Units)
                  h


                   2 98-
                   -
                   .

                   c
                    d
                       C

                       r
                       a!
     n
     0"            :
                   :
                   .d       90-
     Q
     u            f,
                  4
                  v

                  a
                  2         82-
                  2
                  -
                  .I
                  V

                  c:        74 -
                  2
          :   6             6




                            34 -


                            32 -
                  *                                                          C/y@ N        2 74
                                                                                              .
                  2
                  +         30-


                            28 -


                                                                                              M40
              - 62


                            Figure   6a. Relation Between t h e Tendency of Blends t o Crack        and
 I
                                                  t h e M40 Q u a l i t y of Cokes
I'
1


                             38




        G
        9


        82


        4
        7


        6
        6
                 7           8    3   10




h

                                                  ' I




    -    0           Q   Q                 M 10
             6   7           8    9   10
                                           39




                    64     68      72        76       80       84




-   0           3
                    64    68       72       76        80       t
                                                               %


    h 0
    0
        c
        .r(
                    t                               c = Temperature of
                                                     Resolidification




              Figure 7a. Relation Between the Tendency of Constituents
               of Lorraine Coals to Crack and the M40 Quality of Cokes
                                           40




                                                                                       90


                                                                                       50


                                                                                       60
2
                                X



                                                                                       2U


                                                                                       3


h


     6.


     1.
    1.
    ..2
    .1
     .1
      6
            CA   ~20.25

                     7
                         1:         8               9              10




      .-.
      :*i.-.dre 7:. .-,ela+icr, Betveer: the Tendency of C o n s t i t u e n t s o f
       :.crrr?ine Coals t u .AGyI”tinate and the !,11!3 ,Quality of Cokes
                                          p?r It. ZUSSC e t 3. ALIXRII



Rdsund.

                  L-. nouvelle mi-thode de qudific:.tion,                     r.:pide e t m t c i r z t i s n b l e ,   des c h r r -
bon;; consistc;            ne:<xer le p u v o i r r i f l e c t e u r g l o b a l (FRC) de In w r f x e d'une s6ri.e
                                 lamdrdes s o w f o r t e i r c s s i o r . e t scns 1i:fit.
                  Statistiquement l e FRG v x i e d'une faGon l i n c a i r e , c r o i s s m t e , avec l ' i n -
d i c e de ck-.tit'res volp.tiles ( i V ) e n t r e .,@           c t 2C      :
                                                                             ;,                                       .
                                                                                  p i s ddcroft e n t r e 2'2 e t 13 9 Lc
nethode n ' e s t plus -.pplicqble s m s ncdi€icr:cioc ?.u dessous de MV = 13 $. L'Qp?isseur
d e s p c s t i l l e s est nininiim v e r s i.V = 25         ;>.
                              1X Ll =
                               i
                              .~ i
                               R               :
                                               .  ''
                  L c r-pport ' G ' d g = i;C .-L ?.tteint 7; 1 l i n i t e de confi?nce du R G moyen,
                                                              .
B 95 j., e s t de            1   5.              G
                                      pour r i = 3 p z t i l l e s .
                  3ne c o r r d a t i o n s?.ti:;f.ii       t e e n t r e IC FRG du ch-rbon e t 12 qu:iLit@ du
coke     2.   dtk d t c b l i e B p-xtir d ' e s s - i s send i n d u s t r i e l s . Dnns d e s c o n d i t i o n s n c r m l i -
sies de p r e p i m t i p n e t de cob:'q.ction              il 7      '
                                                                       1   une rorrbl-:tion p a c a t d g o r i e de n6-
1:nge.




Intrwcuction.




                                                                                                                   ../.,.
                                                                                                                                          '   I




                                                            42




I - DESCRIPTION SOi"ii*iiJRTC LS :GTIIODE
    _-                       DE
                            -_---                            (1) ( 2 )

               Le souci d ' a b o u t i r k un procQd6 , m t o m t i s n b l e oblik-ait               2 nbzndonner le po-
l i s s a g e e t l a s e l e c t i o n d e s plnges de v i t r i n i t e h o b i t u e l l e m n t p r a t i q u e s %u c o w s du
mesurage du p u v o i r r B f l e c t e u r (PR) au microscope.
               L a mCthode expGrinent6e c o n s i s t e 'a f a b r i q u e r , sous une f o r t e pression, une
s 6 r i e de wstilles dont on E s u r e l e P G de h surface 2 l ' n i d e d'un photombtn?. J n
                                             R
simple ex,men v i s u e l d e s p l s t i l l e s s i n s i p&par6es, montre qu'un 6 v e n t n i l i m p o r t a t
d ' i n t e n s i t k s de r e f l e x i o n e s t d i s p o n i b l e e n t r e l e s charbons f l a m b m t s , type 711, e t
l e s ch?.rbons d i t s "d'nppoint", type 334,                   - v o i r 11 f i g .   1.
               Voici une d e s c r i p t i o n succincte du mr.teriel de l a b o r a t o i r e e t d e s diff6ren-
                                                                                                                                              I
t e s phases d e l a mithode :
               - kprks s i c h 2 . p 2 l ' a i r le ch-rbon est broy4 e t                    tpmis8   < O;5 mm.
               - Une r;.-.chine B comprimer f o u r n i t d e s p z s t i l l e s            dont le diombtre e s t de                I

25 mm. Une pression de 4000 b z r s e s t n d c e s s a i r e pour msurer sans 1i:mt une bollix?
cohksion. Les p i s t o n s e t contre-pistons sont munis de p - . s t i l l e s en carbure d e tungs-
tkne pour r6duire f o r t e m n t I n v i t e s s e d'usure. L?. surfnce du piston sugrieur d o i t
E t r e soigneusement p o l i e .
               -   l e photomktre employ6 fonctionne de h m n i b r e suivnnte : l a lumihre is-
sue d'une m p o u l e      - 6V,     51:   - dont    l'nlimentstion e s t s t i b i l i s g e , est dirigke vertica-
l e n e n t v e r s l?s u r f a c e de la p c s t i l l e h. l ' a i d e d'une lnme semi-transpnente.                   O mesure
                                                                                                                         n
l ' i n t e n s i t 6 de 1 l u m & r e r & f l & c h i e d-ns l a m&ie d i r e c t i o n cu moyen dlun photomulti-
                         :
                         ,
p l i c a t e u r dont 1 ' : i l i n e n t z t i o n sous 1400 V e s t s t a b i l i s 6 e au 1/10 000     &E.
               -   L ' i n t e n s i t g de la r e f l e x i o n e s t indiquee par un micro-mpkremktre.                   b v i -
s o i r e r e n t l e s micro-ampkres ont 4th adoptBs c o m e u n i t 6 a r b i t r d r e .
               -   deux 6 t d o n n a g e s s y s t 6 m t i q u e s a s s u r e n t l e s r e p i r i g e s du P G en vzleur
                                                                                                                R                             I

absolue : Une substcnce Ctalon, q u i peut & r e du ch?.rbon peu d t k r z b l e , sert 'a zesu-
rer . d e r i v e due 2 l ' u s u r e du p i s t o n e t B d Q c e l e r un Bventuel ck.ngeiiEnt de 1 . f o r c e
    1                                                                                                r
d e compression, t v l d i s qu'une s i r i e d ' G t d o n s en v e r r e c o n t r a l e l a s t z b i l i t B de fonc-
tiomement g l o b 2 1 du photombtre.


                                                                                                                  ../   ...
I

                                                                             43


                   Les r 6 s u l t z t s r:entionnds d:ms la prksentc; c0i.i ,unic.-tior: mTrt t.xpri:-i-s couc
    I n fame d'un PRG ;;oyen e n unites a r b i t r a i r a s , Lcyenne de n p - . c t i l l L s f - t r q u d e s 5
    p w t i r d'un r&,e Bchsntillon,                  -
                                     n = 5, IO, 30 ou 50 s e l o n l e s cris r,t d ' u m l i i . i t e        -,
    de confiance de 1: royenne h 9 5 7 s o i t 2 2 = 2 puisquc; 1- d i s p e r s i o n s u i t une
                                     ;               L/-.~      '
    l o i norr.de.       Lorsque n = 30 p ? s t i l l e s l a p r e c i s i o n n l n t i v c g1obr-k d s KLmrzge du
    PRG royen [ est de l ' o r d r e 2 1 b 1 , 5                       .?.   Une cnalyse de v a r i m c r :   -?   nontrd que l e
    r.iajeurc p r t i e de c e l l e - c i est due b la pr6par.ztion de l ' k c h a n t i l l o n , b 2 f s b r i c e -
                                                                                                       1
    t i o n des pastilles e t b d e s dkcclz.$s                        chronologiques e n t r e In f i n de l e f a b r i c a t i o n
    d e s pastilles e t l e debut du w s u r a g e photon6trique. La d i s p r s i o n de ce d e r n i e r est
    trks p e t i t e .

    I1 - FACTEURS INFLULXCAI'TT LE PRG.
         __--
                    Le p r i n c i p de l a n6thode f a i t prevoir que 1 ' 6 t a t de surfece d e s p n s t i l l e s
                 ?
    dependre de l . p r e p a r a t i o n de l 1 6 c h m t i l l o n e t de l a f a b r i c a t i o n d e s p a s t i l l e s , c e t t e
    dependance v a r i a n t avec l e s propri6tBs physiques e t chiniques d e s charbons.

            1 0 ) P r B w r a t i o n de 1 ' 6 c h a n t i l l o n .

                    a) Le sdchage.

                    Une exp6rience a montrB que lorsque l ' h u n i d i t 6 du charbon c r o f t le PRG
    augmente d'abord t&s rapideriint jusqulk une humiditk v o i s i n e de celle de. r g t e n t i o n ,
    puis plus l e n t e m n t .

                    b) L_:-ljroynge        *

              Les rBsultats obtenus avec t r o i s degrbs d i f f b r e n t s de f i n e s s e 100 9 < 1,
    < 0,5 e t < 0,2 mi indiquent que le PRG augmnte jusqu'b 100 9 < 0,5 XI e t q u ' i l n ' e s t
                                                 n
    pas p.v=mtageux de broyer p l u s finerxnt, I s e l e c t i v i t k de IC nBthode n l e n s e r a i t pis
                2
    accrue car 1 porositd de la surfcce ne dininue plus. En outre c e degrk de f i n e s s e
    @ r a n t i t que lr. d i e t r i b u t i o n s u p r f i c i e l l e d e s m c B r m x vnriera a s s e z geu d'une €as-
    t i l l e 5 l'autre.
              .

                         ------___--------
                    c ) L'honogknnkisction de 1'd c h a n t i l l o n broyd est Bvidemmnt indiepensable
    pour a s s u r e r l a s t a b i l i t 6 de l a s t r u c t u r e s u p e r f i c i e l l e de t o u t e s l e s p?stilles.

                    E t a n t dmn6 l'iliiportance de c e s t r o i s f n c t e u r s il est nBcessaire d ' a d o p t e r
    un Rode de prkparation trhs reproductible.

                                                                                                                          ../...
                                                               44


        2 C )   F a b r i c a t i o n d e s wstilles.

                 a) &ee-gr,eng~;z de l a _pastille.

                 Le d i c n b t r e d o i t d t r e c h o i s i e n f o n c t i o n de l a p r e c i s i o n de nesursge ddsi-
r6e e t pour une f i n e s s e de broyage donn6e. Sous cvons ndopt6 25 m. L'Bprisseur dd-
temine          IC r d s i s t m c e n6cmique de IC p a s t i l l e , c e l l e - c i e s t encore trBs s u f f i s o n t e
pour 4 I,
        T.        En c o n f 6 r m t h 1 . c o v i t b de conpression d e Is mitrice, une f o r u e conique,
                                        2
on f n c i l i t e l ' e x p u l s i o n de lr p x t i i l l e e t on Q v i t e l e s              a r r a c h e m n t s pkripheriques.
Deux n u t r e s c o n s i d k i t i o n s secondaires e n t r e n t en jeu : l o f o r c e de l a nachine B com-
primer d o i t c r o f t r e c o m e l e cewri du d i m h t r e t a n d i s que l o q u n n t i t d de 1'6chantil-
l o n B p r d p i r e r est p r o p o r t i o m e l l e B 1'Bpaisseur.

                       ----------
                 b) La p r e s s i o n .

                 Lorsque l a f o r c e de conprcssion au-nte                    l e PRG c r o f t dlabord rapidement
p u s t c n d nsynptoquerznt v e r s me v d e u r ~ x i r i u n . ku d e s s u s de 4000 b a r s l e PRG ne
varie p l u s d'une f a c o n oppr6cinble. L- stc?bilite5 de c e t t e p r e s s i o n d o i t d t r e contr8-
1ke h l t a . d c d'un h s p o s i t i f approprid.

                 c ) Le-%@          de p o l i s s c g e o unc i n f l u e n c e ir2portante s u r lr. v a l u u r du PRG.
La s u r f a c e en carbure de tungstkne du p i s t o n est p o l i e nvec du drop de b i l l a r d inpr6-
gnk de p 5 t e s de d i          m t dont h f i n e s s e c r o i s s m t e n t t e i n t 0 , 2 5 p . L t a l t 6 r z t i o n du
p o l i s' apprQcie pSriodiquerent s o i t i n d i r e c t e c e n t B l1c;ide d ' u n e s u b s t m c e & t a l o n
dont on d e t e r n i n e l e PRG, s o i t d i r e c t e n e n t en u t i l i s m t           WL     d i s p o s i t i f optique.

       30)      ?Iesuroze p h o t o d t r i q u e .

                 ,?)   +-zcne     s p e c t r t d e d ' b i s s i o f f de 12. source.

                 hprks c v o i r s.ms succAs cherch6 l ' e x i s t e n c e de b m d e s d ' i b s o r p t i o n dans le
f?.isce.m r C f l 6 c h i d e p u i s 0,25/L'jusquIh 25,/'nous                zvons, pour des r x i s o n s de conve-
m n c e consntcnde, r.dcpt& une 1::apc h f i l ~ m e n t"ponctuel" courmncent employee en ni-
c r o s c o p i e . Ce choix e s t d v i d e x e n t l i 6 h c e l u i du d 6 t e c t e u r photosensible.                      ,



                 b ) &e_-d&tectz;c de llmikre d o i t Gtre t r k s s e m i b l e puisque le pourcentage
de lu?i&re r k f l ' c h i e r e o t e       inf6rieur i       1   9.   Notre l a b o r n t o i r e Btmt 6quip5 cvec d e s
p h o t o n u l t i p l i c - . t e u r s t r b s s n t i s f a i s w t s , nous -vans continuk h t r a v x i l l e r ovec ceux-
ci. L6ur s e r - s i b i l i t i s p c t r c l e s ' Q t e r d de 30001 h 6500           fi        av6c un maxinun h 4203            2.
                       ---------------_-_______________________--------------------
                 c ) Llictem.i.lle de te;pq u i s6pax-e In f a b r i c a t i o n d e s p a s t i l l e s de l e u r
pg"u_r"ge       pflotondtrigm, d o i t Eti-           c o n s t c x t , en e f f e t l e PRG de 1i s u r f m e d e s ps-

                                                                                                                                    ../...
    t i l l e s dininue r?.pideuent pendFnt l e s deux p r e n i k r e s h e u r e s puis se s t z b i l i s e e n s u i t e .
    L ' e x p l i c c t i o n de c e t t e d J r i v e f a i t l ' o b j e t de recherches. De t o u t e m n i k r e c e t t e con-
    d i t i o n sernit .nis&ent r e n p l i e nvec un d i s p o s i t i f cutomatique.
           :Lo)   Les propriBt6s physiques e t chimiques d e s chnrbons.
                    a) L 2 t i t u d e B l'agglom6;ntion           sans l i m t .

                    D 40 & 20 f de NV environ, l e PRG augnente ovec le r m g (fig. 2, courbe 1 ) .
                     e
    C e t t e augnentction e s t due, d'une p u t B 1':ugnsntation                      du PR de t o u s l e s macdraux,
    d ' n u t r e Rrt h l ' a p t i t u d e d e s ch-rbons B s ' o r i e n t e r p e r p e n d i c u h i r e m n t h l a compres-
    s i o n , q u i .iugmxte e l l e m s s i de 40 B 20 $ PlV t m d i s que 12 p o r o s i t e de l a s u r f a c e
    d e s p z t i l l e s (nesur& 2u m i c r o s c o p ) s'ab2.isse de 25 & 10 5 d m s l e d m ' n t e n r a l l e .
                                                                                                i
    ku dessous de 20 $ de i W le PRG b a i s s e m d g r 6 1 ' a u p n t r . t i o n c o n t i n u e du PR d e s ma-
    ckraux, c e c i Btmt dfi & l a d 6 c r o i s s m c e r n p i d e d e l ' a p t i t u d e au pastillage, l a q u e l l e
    d i s p o r a i t totclement v e r s 13 $ W. Au mxituum de l ' a p t i t u d e au pcstillage correspond
    l e m i n i m d ' 6 p n i s s e u r d e s p a s t i l l e s ( f i g . 2, courbe 2 ) , ce m i n i m p r n i s s a n t 6tre
    l6gkrement dkcnlk (25 $ iIV) p.r r a p p o r t ?u               maxirmu3    de PRG (21       5 IW).
I                   b) k c n p r e s s i o n couplke       B une r o t a t i o n r a l e n t i t IC b a i s s e du PRG nu des-
    s o u s de 20   $ de    iiV niis ne L3 suppriine pns. Bprks essais cette technique ne nous a
    pas paru c v m t a g e u s e c c r l ' u s u r e du p o l i du p i s t o n e s t t r k s zccklkrke.
                    c ) Lc proportion d e s mtGres min&mlesL c m x c t 8 r i s 6 e p a l e tzux de cen-
    d r e s , influencer:? diffkremnent l e P G d e s ck-.rbons selon l e s nive,?ux r e s p e c t i f s du
                                             R
    PRG d e s chzrbons purs e t c e l u i des r s . t i b r e s n i n 6 r a l e s . Des e x & r i e n c e s s y s t k m t i q u e s
    c n t nontr6 que, dzns l e c n s d e s s c h i s t e s ou d e s Iuixtes pour l e s q u e l s le P G e s t peu
                                                                                                     R
    d i f f b r e n t d e s chirbons de b?.s r n g , l e P G v:?rie peu. De p l u s l e t a x de c e n d r e s de
                                                          R
    IC p l u p x t d e s ch-.rbons f r - z q a i s ::prBs h v n g e , m s t e const,-nt L 2 1 h 2 $                 prks. Ainsi
    pour l e s ch?.rbons peu h o u i l l i f i J s e t m61re pour l e s chorbons d o n t l ' i n d i c e de I.Iv e s t
    v o i s i n de 20 ). l e s f l u c t u n t i o n s cournntes du taux de c e n d r e s n ' i n f l u e n c e r o n t pas nota-
    b l e n e n t l e TRG. C'est ce que nous avons pu v e r i f i e r p l u s i e u r s f o i s .

           !io) v x i c ~ i o n s I n composition nac&role.
              Les               de

                    E l l e s r:ffecteront l e PEG drms In Liesure o h l e s P d e s nzc6raux s e r o n t trks
                                                                              R
    d i f f d r e r t s e t c ' e s t certr:inemnt   UIE    p o s s i b i l i t d de perturb?.tion de l a q u , d i f i c c t i o n
    q u ' i l convisndr: d'ex,.niner :Ivec s o i n , r.i?is nous             M:   possQdons p.s encore s u f f i s . m m n t
    de rCsult?.ts pour d i o c u t e r c e p o i n t ,


                                                                                                                 ../...
                                                             46


                Cependnnt sur IC base d e s connoissances p6trogmphiques zccu.uul6es t.xt
c u Cerchar (4) q u ' 8 l'ktrmger,                  - et en pcrticulier              en k l l e m w p e , e n Belgique, e n
Bollande      -,   il e s t p o s s i b l e d e p r k v o i r l e s e n s des n o d i f i c c t i o n s du PRG.

                a ) A d e s s u s d'une t e n e u r e n corbone de 90-92 $
                     u                                                                        - correspondznt            h 22-23   j:

de I W   - les     trois p r i n c i p z m wc6roux ne s e d i s t i n g u e n t p l u s pcr l e u r W G . C'est
donc s u r t o u t dnns l e c a s d e s c k r b o n s de r.mg f n i b l c que I n conposition r t l c b r d e
p o u r n i t m o i r une i n f l u e n c e . En f l i t &he pour un c k - r b o n h 40 2: de iW l e P d m s
                                                                                                      R
l ' a i r de l a v i t r i n i t e n ' e s t que lkgkrenent p l u s gr-.nd que c e l u i de l ' e x i n i t e .
                Le PR de l ' i n e r t i n i t e e s t nu c o n t r < a i r e d e j a t r g s &lev&. Des f l u c t u a t i o n s
i m p o r t m t e s de lc p r o p o r t i o n d ' i n e r t i n i t e pourrrzient j o u c r un r81e npprkciable. Une
? . u p n t n t i o n de l a p r o p o r t i o n sersit i n t e r p r 6 t i . e c o m e une Bldvation du rnng e t pra-
t i q u e m n t l e chzrbon se comportera sons doute come s ' i l Qtait amaigri.
                Ceci n ' e s t vnl-ble en f a i t que pour l a fusinite                                t o u j o u r s t&s peu
                                                                                                                                        '

nbondmte dims nos chzrbons p-.r r a p p o r t & la s e m i f i s i n i t e , c e l l e - c i de                    PR trks va-
r i z b l e , e s t l e c o n s t i t u x t p r i n c i p l l du g r o u p de l'inertinite.

                b) 'Les m p p o r t s
                                           V et   v v s r i e n t g6nGrCtenent p u nvec l e rang.                      Lorsque le
chmbon e s t p r J l e v l B l a s o r t i e d ' u n l c v o i r q u i t r a i t e un nelmge de p l u s i e u r s v e i n e s
s i t u t j e s & d i f f d r e n t s &ages l e s v z r i n t i o n s s o n t bien q o r t i e s . Ceci ne serait probn-
blement p l u s v r a i s i 1 ' 6 c h ~ n t i l l o n n - - g e o r t a i t
                                                              p                    une
                                                                               9 u ~     veine s i n g u l i k r e .


 1
11    - FEL:ITION       ZXT'RE LE P G ET L'IBDICE DES IW IES C~ARBOXS.
                                   R

                L'exp6rimentttiorL d e l a &thode sur p l u s i c u r s d r i e s de chnrbons d' o r i g i n e s
d i f f k r e n t e s , Frilev6es pour l a p1Gpx-t dnns l e s wagons & l ' a r r i v k e en c o k e r i e a per-
nis. de t r a c e r l a courbo de L f i g . (3) q u i s ' k t e n d sur t o u t l e d o m i n e d e r a g d e s
                                   z
chnrbons enployds en cok4fnction.
                On c o n s t a t e que l e R G p l s s e de 1 & 7 l o r s q u e l ' i n d i c e de PI'V diminue de
                                            I
n o i t i s , s o i t e n t r e $0   :
                                     5   e t 20 $. Au d e s s o u s de 20 $ le FRG d k c r o i t r a p i d e m n t pour
les r c i s o n s ddjh exposdes ?.u paragraphe I1 4 b, e t ne p u t plus 6 t r e d 6 t e r n i n 6 au
dessous de 13 23. L'Bpaisseur d e s p:.stilles                        v o l i e e n sens oppos6. La d i s p e r s i o n d e s
donni-es est due e n p r t i e B ce qul8 l'kpoque dBjB ancienne de ces % a r e s t o u t e s les
causes de d i s p e r s i o n n'kt,.lent                                                                      R
                                                  pas Glininkes. L'klargissement de 1 ' k v e n t a i . l du P G
par r a p p o r t & c e l u i beaucoup p l u s restreint du PR de la v i t r i n i t e ,                    - qui       d.ms le &me
d o m i n e ne v a n e que de 0,65 & 1,5                 -, r d s u l t e     d'une p a r t de l o s o m c t i o n ktendue &


                                                                                                                       ../...
                                                                  47


t o u s l e s mc6raux e t d ' a u t r e p n r t de l o v c : r i z t i o n i m p o r t m t e de l ' n p t i t u r i e        l'zgglo-
n 6 r n t i o n sous compression a u t r e m n t d i t : de la d u e t 6 d e s charbons.
                 Le PFiG permet donc de c l a s s e r l e s chcrbons IwGs rdcemnent s e l o n m ordre
de q u a l i f i c i l t i o n t r b s proche de c c l u i que f o u r n i t l ' i n d i c e d e HV,


IV   - -~ PRG ET LES FROPRIEES COKEFIANTES DES CHAX3ONS ET D3S ILL;INGE.>.
       RELldION ENTm Lt:

                 Cette m&thode de q u c l i f i c n t i o n a dt6 exp6rimntGe p r i n c i p l l e m e n t en vue de
c l a s s e r les d i v e r s charbons consid6rds i s o l g n e n t s e l o n l e u r s p r o p r i 6 t 6 s c o k 6 f i m t e s .
Cet o b j e c t i f pouvnit p a r a i t m utopique puisque t o u t e s l e s t e n t c t i v e s f a i t e s jusqu'h
n a i n t e n c n t n' ont conduit q u ' m d6veloppecient d e s ni6thodes i n d i q u e e s ci dessous (*)
                                       u
e t q u i mesurent sp6cifiquenent l'un , l ' a u t r e d e s deux a s p e c t s c o n u U n e n t a i r e s de
c e s propri6tGs. L ' o r d r e d e s ncthodes d ' 6 n m 6 m t i o n correspond                     B une a p t i t u d e dhcrois-
s a n t e h lo cuse e n dvidence de c e s a s p c t s :

        PropriGtks a s g l u t i n m t e s                                 Aptitude h l a f i s s u r a t i o n i n t r i n s h u e
Gonflement 2u d i l a t o n b t r e        - Essai      Gray-King           'Penpkrature de r e s o l i d i f i c e t i o n au
                                                                                p h s t o m k t r e b couple v n l i c b l e
I n d i c e Roga ou i n d i c e s d ' i g g l u t i n a t i o n
                                                                            C o e f f i c i e n t de c o n t r a c t i o n h l a tem-
I n d i c e de gonflenent zu c r e u s e t
                                                                                  p6rclture de r e s o l l d i f i c a h o n
I n d i c e s de f l u i d i t 6 aux p l n s t o n b t r e s
                                                                            I n d i c e de m t i h r e s v o l o t i l e s

                 En f?it il convient de t e n i r conpte d e s renarques s u i v n n t e s :
     - I1 e x i s t e une      r e l a t i o n stctisticiu_e_ n t r e l ' i n d i c e d e s i9IV.o~l e r a g e t les pro-
                                                            e
p r i d t e s a g g l u t i n m t e s , c e l l e s - c i n u l l e s au dessous de 13 $ o u g m n t e n t e t p2ssent par
un m x i m v e r s 28          $?   p u i s d d a r o i s s e n t e t s'nnnulent au d e l b de 40           5.   Le m x i m
                                                                                          q u i a u d e s s u s de 5
s ' e x p l i q u e r z i t par l ' a c c r o i s s e m n t rzpide de l a t e n e u r e n 0
                                                                                        2
e n v i r o n pour 28 $ de IW d e v i e n t nssez obondant                   pour provoquer une dhgrndntion d e
p l u s e n plus e f f i c a c e des propri6tGs cgglutinnntes.

     - Le    PRG & a n t db p r i n c i p d e u e n t 2 12 v i t r i n i t e , q u i c o n s t i t u e &n6rdement 60
h 80       FC   d e s charbons, t o u h v a r i a t i o n de lc composition chimique d e c e l l e - c i a u r a
une i n f l u e n c e sur le PRG. En p x t i c u l i e r ce w C 6 r d contenant L? ImjeJre p r t i e de
l'oxyg&ne du chcrbon une t e n e u r c r o i s s a n t e en oxygkne de c o n s t i t u t i o n s'nccompgnera
d'une b z i s s e du PR         (3).
                                                                                                                       ../. ..
                                                                                                                             ~   ~~~




(*) La p l u p a r t d l e n t r ' e l l e s s o n t u t i l i s C o s dzns l e p r o j e t de c l c s s i f i c n t i o n i n t e m z -
      t i o n a l e q u i p e n e t de d 6 f i n i r l e type du c h x b o n . (5)
(3)   L'oxygbne de combustion ou d ' o x y d i t i o n exothermique n'aurc? sms doute 10s l e dm
      e f f e t s u r l e PRG.
                                                                  48'



                  En ce q u i c o n c e m e h r e l a t i o n e n t r e l e s p r o p r i d t 6 s cokefiantes des milcn-
ges 6vrlu6es pcir d i f f b r e n t e s iut-thodcs, dont notre n6thode du                        PRG, e t l e s c a r < x t k r i s -
t i q u e s princip-.les d e s cokes (*) i s s u s de ces dlmges, nom p n s o n s q u ' i l n ' e x i s t e
p s s de c o r r k l n t i o n g d n c r d e ; il f x d r z 6 t a b l i r Lz r e l z t i o n pour c h q u e cat6gorie de
n6lmge. Cette pr6viuion ddcoule d e s c o n s t a t r t i o n s e x p 6 r i m n t a l e s suivaxtes (6) :

        - pour une         c n t 6 g o r i e donni-e de m k l m g e s ,   - par exenple ch.-.rbons 334 + 632 -, il
e x i s t e u r e l n t i o n e n t r e les i n d i c e s M $0 e t W 10 e t 1% proportion de charbon 334.
             w
En cons6quence on p u t d t c b l i r une r e l a t i o n e n t r e 12 y u d i t 6 d e s cokes e t la plu-
W r t d e s pmpridti-s c o k k f i a n t e s de c e s &lan@s. Notons cependant que l e s propri6-
t&s cokSfiantes des chzrbons c o n s t i t u a n t s ne sont pis a d d i t i v e s c a r la q u a l i t 6 du
coke s ' , m 6 l i o r e ropidenent :iu d6but lorsque l . proportion de charbon 334 augmente,
                                                       ?
w plus lentecient v e r s 30
 s                                              ><:   e t e l l e se stabilise presque au d e l i de 50 ? 60
                                                                                                        .I                    56.
        - L c rkgle        logique q u i p r e v o i t que h f i s s u r a t i o n du coke diminue lorsque l ' i n -
d i c e de IIV du r i l z n g e b-isse n ' e s t v 6 r i f i d e que pour l e s c a t 6 g o r i e s de dlanges de
                                                                                                e
chzrbons dont l e gonflenent zu d i l - t o n k t r e r e s t e suffisctnt p u r a s s u r e r m bonne
n g g l u t i n a t i o n donc une b o r n cohision. Lorsque c e l l e - c i s ' n b c i s s e 1u h s s o u s d'un
                         i
c e r t s i n s e u i l l?f i s s u r a t i o n p u t c r o i t r e ; l ' i n d i c e M 40 diminue a l o r s parce que
l a f i s s u r a t i o n e t 12 dkgrcdction par abrasion sont accrues. Pour l e s memes r a i s o n s
deux m6lmges ?.ycnt IC&he                        i n d i c e de IN peuvent f o u r n i r deux cokes de q u d i t e s
t r k s diffkrentes.

        - La     pr6sence dcns l e aSlm@ de substances i n e r t e s ,                      - matikres          min6rdes        -,
ou de c o n s t i t u i n t s . m t i f i s s u r ? n t s ,   -   poussier de coke    -, Z f f e c t e r a   tr&sd i f f 6 r e m -
mfit l e s cz-




                     4
                                                                                                                    ../.:.
(*) I n d B p e n d m e n t des p r o g r i d t Q s chimiques des cokes, de leur masse volumigue e t
      de 32 d i s t r i b u t i o c g r m u l o & t r i q u e , l e s deux c a r c c t k r i s t i q u e s u t i l e s pour
      l ' u t i l i s n t o u r s i d C m r g i s t e sont : l ' i n d i c e PI 40 q u i repare l a r k s i s t m c e 21 12
      fissur::tior? e t l ' i n d i c e i.l 10 q u i mesure l ' a p t i t u d e         B L d6gradation par abra-
                                                                                           ?
      sion.
                                                                        49


     r n c t d r i s t i q J e s d e s cokes s u i v m t leur d e g i de d i s p r s i o n e t l e u r proportion. C'est
     ?.insi lue lr! concentr;.tion optimun en poussier de coke broyk                               < 0,5 nm n ' e s t p;s 1.7
     dme s i l ' o n ccnsid;-rc l ' i n d i c e      ij   $3 ou l ' i n d i c e    ?I io.   D ~ i cert.xins
                                                                                                  s            CT.S   c e t t e concen-
     t x t i o n p u t 6 t r e 5 :r pour l e 11 10 e t 10 h 15               '
                                                                             .
                                                                             F    pour le N CO.
,                   Ces longues considkrztions $nkr,?.les donnent un ZperCu de l ' i n p o r t r n c e e t
     du nombre des f-cteura q u i i n t e r v i e n n e n t pour d i v e r s i f i e r le3 r e h t i o n s e n t r e les
     qu-lit&      des chsrbons, d e s m k l m g e s e t d e s cokes.
                   Iieureusenent lc ccmplexitk d e s ktudes s e trouve souvent r k d u i t e lorsque
     l ' o b j e c t i f de 12 q u n l i f i c r t i o n e s t r e s t r e i n t eux prob16mes de cokdfaction i n h d r e n t s
       un bnssin h o u i l l e r ou 3. une cokerie.
                   L ' c p p l i c e t i o n de c e t t e d t l i o d e k 1,,prbvision d e s p r o p n 6 t 8 s c o k 8 f i a n t e s
     n ' Btant p?.s encore trhs dtendue nous ne xentionnerons que quelques expkrimentntions
     syst6mctiques de 1eborc.toire ou s e m i i n d u s t r i e l l e s dont l e s r 8 s u l t n t s sont tr6s en-
     couregew-ts.

            l o ) V d r i f i c a t i o n de 1 ' a d d i t i v i t B du PRG e t c o r r e l a t i o n avec d ' m t r e s nG-thodes
     de q u a l i f i c a t i o n (en l?.borntoire).

                   iiu l a b o r - c o i r e on n prdpzre deux s k r i e s de mdl:m@?s b i n z i r e s , l'un 2 bnse
     de chr.rbon 622 ?uc,uel on c ajoutk une proportior? c r o i s s : m t e de charbon 333, e t l ' a t r e

ii
     ? base du m6xe chzrbon 622 zuquel on e d d i t i o n n n i t du ChWbOn $7.;. Comw &vu
     I                                                                                                                       le FRG
     du mdlmge v r r i e l i n e - i r e n e n t nvec l a proportion de ch?.rbon de z - : g Blevi e t a u s s i
     avec l ' i n c i i c e des w t i h r e s vol::tiles,       cu moins jusqu'h 75 j: (fig. 5). iiu d e l h l ' i m -
     p r d c i s i o n de l . courbe est due au p t i t nombro de p:.stilles
                           r                                                                      mesur6es e t zu f a i t que
1
1    c e t t e expBrience    il                                                                                           .
                                  6tB f . i t e t o u t du d i t u t de l ' e x p 6 r i m n t c t i o n de I n rniithode; 5
 I
     c e t t e -pSriode l e s c,?.uses de d i s p e r s i o n n'Qt:.ient p s t o u t e s connues.
                   Corrklztiveneiit on trouve mssi m e bonne r e l n t i o n e n t r e l e PRG e t l e gon-
     flenent    FLU   di1r:tczktre (fig.         5), cn remirque 2ue              r l w s l e d o m i n e d e s f z i b l e s pourjen-
     tr.ges de chrrbor, de r m g 8lev6 oh 1- d i s p r s i o n de d6ternin::tion                         du gcnflenent e s t
                             Cp
     rissez g r m d e , l e W - u t &trerresurd w e c une p r i c i s i o n t r b s s-ltisfei;nr?te.
                   &intcx?ct,         en t e m f l t compte d e s progrhs obtenus d:ms 1' p p l i c a t i o n de
                                                                                         a
     c e t t e +tkLode il e s t posrjible de distin&.uer dcux ndlnnges dont l e s proportions d ' n p
     p o i n t rliff&rr?r.t senlenent de 2 ?-.

            2 " ) w e t i o n e n t r e l e PRG e t       IC c u d i t 6 deo cokes obtenus e v t c d i f f e r e n t s m6-
     l m a e s . ?remier      essai      oeni i n c h s t r i e l   .
                   Le::   ess2.13 de convenrnce de 1 : mgthode r n t d t 6 p o u r s u i v i s en 6tr.blissant
                                                    ,

                                                                                                                  ../. ..
                                                              50



l e s r e l a t i o n s e n t r e 1 1 q m l i t 6 d e s cokes e t l e FRG des m 6 l r s , p s
                                   .                                                                -   er: coll.zboretion
avec 1~.t z t i o n Z x p 6 r i m n t n l e de cok6f-.ction de kieriemu. Le tzkle7.u c i dessous ic-
       S
dique l a composition d e s 8 m6lmgees 6 t u d i d s .

!                                                                                                                             !
!                                                : T y p e t proportion des c h - r b x s c o n s t i D m q t s               !
!                                                :--------------------------------------------!
!         N6l . n s
               a&                                : 335           :     $34       :     635              622                   !
!-------------------------                       :---------'.-----------:-----------:-------I
!                                                :   30     :                   ,:            70           :                  !
!   bincires                                     :   25     :                      :          75           :                  !
!                                                :   20     :                      :          m           :                   I
I                                                :   10     :                      :          go           :                  !
!-------------------------:-------:-----:----------:-------!
I                                            :      13              :        27        :                   :        60        !
I ternnires                                  :      12             :         23        :                   :        65        !
!                                            :      10             :         20        :                   :        70        !
I                                            :       6             :         7 7 :                         :        75        J
!                                                                                                                             !

               Ces i&langes broyds m6thodiquement 100 $                           < 3 m, ont dtd e n f m r n 6 s s e c s ,
HzO = 2 $, d r y s d e s f o u r s de 400 kg. Pourchaque m6lmge on                          ;
                                                                                            7   cok6fik deux c h r g e s
                                                                                                                                    1
dans d e s conditions n o r m d i s d e s . Le PRG a e t 6 d e t e r n i n e , pour chacun d e s charbons
c o n s t i t u a n t s de chaque melange, sur 10 p a s t i l l e s . Le P G du d k n g e c d t 6 c a l c u l 6
                                                                          R
b p a r t i r de c e l u i d e s c o n s t i t u m t s puisque la d6monsCrction d ' a d d i t i v i t k l e pmt-
tait.
               k l ' e x m e n d e s courbes de IC figure 6 on rei.%rque que l e P G c e l c u l d ,
                                                                                  R
clinsi que l l i n d i c e de IW du mdl.mge, e s t relie                  B IC r e s i s t a n c e 5    l a fissuration des
                                                                                                                                    4
                                                                                                           I
cokes, m s u r d e p.r l ' i n d i c e M 40 pzr une c m r b e unique, d o r s que pour l ' n p t i t u d e ?
l l a b r a s i o n , d o d e par l ' i n d i c e M 10, il e x i s t e une c o m b par categoric de dlcnge.
Le M 10, b i e n r e l i e au gonflement ,-.u dilntomhtre e s t a prdw. par l ' i n d i c e d e gon-
                                                                 d
flement au c r e u s e t q u i      nli?   aucune s e n s i b i l i t b d v l s l a z6ne d ' i n d i c e de KV situee e n t r e
20 e t 33    9.
               La qiir.lit6 d e s cokes 3e a i i x e , pour k p l u p r t , dans l e domaine d e s cokes
m6tcillurgiques f r ? m p i s pour l e s q u e l s l ' i n d i c e Pi 40 d o i t d t r e sup5rieur & 7 E et l ' i n -
d i c e M 10 i n f k r i e u r ?
                               I   e-   6,5.
               Le n i v e m p l u s b a s de coh6sion d e s cokes obtenus ? plrtir des m5lznges bi-
                                                                          I
n a i r e s s'explique bier, par l ' e x c b a d ' a p t i t u d e i l ' a g g l u t i n e t i o n de c e t t e c c t d g o r i e
de m61ang : l e s cokes contiennent d e s proportions c r o i s w n t e s de mousses lorsque
l e pourcentage do chr,rbon 634 wgmente.

                                                                                                                    ../...
            3O)   Recherche d'une r e l a t i o n e n t r e l e PRG de p l u s i e u r s chr.rbons du b-s.sir.1 lor-
    rain e t 1:~ u a l i t 6 d e s cokes. Deuxi&me esxai semi-industriel.
                q
                    kprks l e s r d s u l t a t s e n c o u r a g z m t s r,Zpporti.s c i dessuus il conver:-it                      de v6-
    r i f i e r que l:i mdthode p e r n e t t c i t d ' d v z l u e r l e s propriBtds c o k d f i - n t e s d e s c h - r b o c s
    d ' o r i g i n e s diverses. Le b s s s i n l o r r n i n put f o u r n i r nux c o k e r i e s e i d d m r g i q u e s e t
1   minikres quatre t y p e s d i f f e r e n t s de chirbons : 722                  - 623 - 633 e t        634/635 i-noncis
    p r ordre c r o i s s c n t d e s p r o p r i e t d s ,aggluticintes. La q u a l i f i c a t i o n de c e s c k r b o n s
'     l ' a i d e du PRG a 6 t h expbrimentbe d m s l e c a s d'un n6lmge humide (H 0 = 10 $) en-
                                                                                                         2
    fourn6 nprks p i l o m g e e t q u i c o n t e n a i t :
I                   chnrbon l o r r a i n (634 h 722)                                      72   p
I
                    charbon d ' a p p o i n t 434                                          a$
                    poussier de coke r t n t i f i s s u r n n t                             8$
                    Les charbons 6taien&@$                   < 2 mm,      l e poussier de coke 1 OC             $<                    0, Srn
    Pour chaque c a t 6 g o r i e de charbon on a enfournd                    4 charges e n f o u r s 400 kg. La messe
    volumique de chzrgement moyenne Qtait 970 kg/n?.                               Les conditions de c o k e f a c t i o n corres-
    pond.Gent       ? lles
                     ci
                      e           d e s c o k e r i e s minihres lorraines. Gn d d f a u r m i t l e s cokes a p r k s st2-
    b i l i s a t i o n thermique presque complhte, c ' e s t B d i r e lorsque l a temperature dans l e
    plan mQdian du saumon atteig-mit 111OoC.
                    Les m e i l l e u r e s c o r r d l n t i o n s avec l e s d i f f e r e n t e s dsthodes de q u a l i f i c a t i o n
    essayees sont rmsembldes d m s l a figure 7.
                                          .
                    On r e m r q u e que k p l u p 3 r t des chzrbons se c l a s s e n t s e l o n une courbe rdgu-
    l i k r e en i l 40 e t €4 10 l o r s q u ' o n porte en a b s c i s s e le PRG mesurG du chcrbon 1orr.Cn.
    L c cohesion du coke t1 10 est a u s s i b i e n r e l i Q e              2.
                                                                               u    gonflenent au c l i l a t o r h t r e , B l ' i n -
    dice d'agglutimtion.
                    Bien que c e s r d s u l t a t s s o i e n t 9 nouvem tr&ss z t i s f . l i s w . t s nous estimons
    qu'une v e r i f i c n t i o n p l u s rigoureuse p o r t a t sur un d o m i c e de q w l i t d plus vnste e t
    s un nombre d ' 6 c h a n t i l l o n s beaucoup plus grand est ndcessaire m a t de p o r t e r
     r                                                                                                                                 LIE

    jugement d d f i n i t i f sur' 1 . v d e u r de IC mgthode.
                                     "
                    Une t m i s i k n e s 6 r i e d'exp6riences send i n d u s t r i e i l e s , e n c o w s d ' e x 6 c u t i o n
    prmettra de compzrer s t a t i s t i q u e w n t l e s d i f f d r e n t e s methodes de q u u - l i f i c e t i o n que
    nous considdrons zussi c o r n v.?lz.ble s m i s pour l e s q u e l e s 1'ni-tomatisntion s e r c i t
    plus d i f f i c i l o .


    v - COBCLUSIONS.
        ___---
                    L ' i n t Q S t d e cette mdthode r 6 s u l t e r a de 1- b d z n c e , p e s encore d e f i n i t i v e -
    ment Q t a b l i e , e n t r e ses p o s s i b i l i t d s e t s e s l i m i t e s conplrat1vemer.t nux p e r f o r m c c e s
                                                                                                                        *   ./
                                                                                                                                 /
                                                                                                                                     ...
                                                             52


d e s - u t r e s methodes de q u n l i f i c r t i o n employees e n c o k d f i c t i o n e t qui s o n t basees
s o i t sur l e s coaporterxnts de              12    h o u i l l e en c o u r s de p y m l y s e , s o i t sur les d e t e r -
n i n c t i o n s p6trogrcphiques du rlng e t de composition m c & r d e .
                En rLsun6 on p u t Bnundrer l e s princip.ux mentes de la m6thode Qvaluds
p z r r n p p o r t B une l c h e l l e de rmg donn6e p i r les i n d i c e s de I :
                                                                                 W



     c)   - l a quolification           t l e n t compte 2 l a f o i s de 1 m-ture d e s mcdraux e t de
                                                                          ,
                                                                          :
leurs p m p o r t i o n s , c e q u i f z i t une s o r t e de synthhse des p m p r i i t d s c o k 6 f i m t e s ;
     d)   - LI p r e c i s i o n d e q u a l i f i c c t i o n p u t 6 t r e trks g r a d e pour deux r a i s o n s      : la
s o m 2 t i o n d e s F'R p o r t e sur p l u s i e u r s d i z z i n e s de m i l l i e r s de p n r t i c u l e s ce q u i Qli-
miw en g r a d e p a r t i e l ' e r r e u r dtc2ckntillonnnge, de plus par l a p o s s i b i l i t e d'zuto-
m t i s a t i o n il e s t a i s 6 de m u l t i p l i e r l e nombre de p s t i l l e s mesurdes.
                En regard de ces n s r i t e s , il convient de p r i c i s e r l e s l i m i t e s e t l e s sus-
c e p t 1 b i l i t i . s de l a nethode :
     e ) ou dessous de 13           $ de    )71     11 mhthode n'est plus oppliccble sans une a d a p t a t i o n
n o u v e l l e q u i pourr-;it c o n s i s t e r h 2 j o u t e r un l i p a t ;
     f ) de 20 5 17       $ de FIV l a diminution rapide de l'clptitude h l'agglom6ration en-
t r d n e une b-isse du FRG. I1 e n r d s u l t e une nclbiguit6, ?I un dme PRG il correspond
deux i n d i c e s de i.N d i f f e r e n t s . Cette confusion p u t 6 t r e supprim6e en mesurnnt s o i t
1 ' B p i s s e u r des p m t i l l e s , s o i t    13   force de compression d e le machine ?I comprimr du
.type m6caniqu.e;
    g ) b i e n que L-, &thode s o i t gGn6rolewnt peu s e n s i b l e 2 l o proportion de nntikres
m i n 6 r d e s d e s ch?.rbons l z v t s , h n a t u r e de c e l l e s - c i pourrclit d a s c e r t a i n s c a s par-
t i c u l i e r s provoquer un 1Jge.r d8cl:ssement.
    h) 1 ' d c b . n t i l l o n de charbon sounis h l a d t h o d e d o i t 6 t r e pr6p..r6 d'une fnpon t r b s
r e p r o d u c t i b l e , m i s cel?. e s t mssi indispenscble pour t o u t e s l e s z u t r e s d t h o d e s de
q u a l i fi cztion.
    i) Win l e cl-sseinent p a r qu::lit6                    B l t o i d e du PRG p o u r r n i t 6 t r e p r t u r b 6 dans l e
c o s OG l t 6 c k i . ~ ~ t i 1 l o n n ~ . & -
                                             ?urr.it 6 t 6 pr.tiqud sur une zone s i n g u l i k r e du g i s e n e n t dnns
l a q u e l l e 13 conposition nc;c6rale s1 6ccrterr.it bzcucoup de la composition moyenne no-
t x m e n t en c e qui concerne IC f u s i n i t e .
               En conclusior, : b i e n que c e t t e m6tiiode s o i t , c o m e IC m j o r i t 6 d e s a u t r e s
n6thodes, s u s c e p t i b l e d ' 6 t r e infirnGe dans quelquc-s c a s @ r t i c u l i e r s , nous p n s o n s
q u ' e l l e ser-. ap?licnble cu c l z s s e m n t d e s chzrbons u t i l i s e s d a s l e s c o k e r i e s aprhs
q u e l q u s s p e r f e c t i o n n e z e n t s q u i nccorilr-gneront son t r m s f e r t d l a b o r a t o i r e dnns la
                                                                                              u

                                                                                                                      ../...
                                                                       ,53 I



        pr-tique i n d u s t r i e l l e .
                       ilous' exprimons n o t r e reconmissonce e t nos rernerciements                            B 14onsieur le
        I'rssidont !I. Berry :pi               ?.   accept6 d e p r e s e n t e r & n o t r e p l x e c e t t e comunicztion.




    1   - jLE1:IEI (3.)        e t BUSS2       (s.::.)     - I d e n t i f i c a t i o n rcpide    e t nutom?tisi:ble   du rang
                     des cinrbcns p?,r msur.-.;-                 -le l e u r r k f l e c t m c e globcle
                     Dccul-nt       I n t 6 r i e u r du Cerch-r no 1 3 i 5         -   1963 ( f 6 v r i e r )

    2   - ;revet      no 1 27G 70- G 01 n d e r n d 6 l e 22 j u i l l e t i96C
                    Proc6dt d ' i d e n t i f i c z t i e n e t d v e c t u e l l e m n t d ' z m l y s e de m t i k r e s riu de
                    nztdri-ux -.&;lon&:bles                  ou s u s c e p t i b l e s d ' t t r e ogglon6rds.


\
    3   - GREISCSY (X.R.) - Un nouver.u                   p-oc6d6 d ' 2 g g l o n 6 m t i o n du chcrbon sans l i e n t
                    J. of I n s t i t u t e of Fuel. XLXI.11 (196C), n0236 ( s e p t e n b r e ) , 447-61

    4 - A L P E L (3.)         - P r o p r i i t Q s p!iysico-chiriques           e t c o k 6 f i : a t e s d e s m c k r m x de quel-
                    ques ch-.rbons en f o n c t i o n de l e u r degr6 de h o u i l l i f i c - t i o n .
                    Revue Industfie K i n d r d e , Vol. X U L ' I . 1 1 ,              (1';5G),     n063@, p.170-161

    5   - C l z s s i i i c n t i o n internc.tioc-.le       .les !ioJilles 2:
                                                                             r           n?ture
                    C.PT.2.     GenBve, i o C t i ? j G

    E   - ?@C?     (T.),      3:USzC (R.?:.)         - Choix d e s x h l m g e s de        chnrbons drms 1-s c o k e r i e s si-
                    d:rurgiy:,e      s lorriizes
                    ?.exwe I n d u s t r i e iiinGr,le 155E,              :9
                                                                         :@ (septu-bre)
           LCISE; (2.) e t ?I.C:-:           (E.) - S-.yport sur l ' , : . c t i v i t & de IC %:.tion            Expdrimnt?.le
                    de :.-.nkfl.?.u er. 1962
                    5ote ~ec:..ciqu.e 3 / 6 ; des Ck?.r3ruor.r,:-.gc-e de Prrmce
                    2 e v x I n d u s t r i e I;inCr-:le .:3, ( 1 -61 ), n09 (septec!bre)                  , 593-616
                                                                    .   54



                                   M i c r o s t r u c t u r e V a r i a t i o n i n P i l o t Oven Coke

                  J. L. Bayer, Research Engineer and C. W. Hansen, Research Engineer

                                          Research and Development Department
                                         The Ycungstown Sheet and Tube Company
                                                    Youngstown, Ohio
INTRODUCTION

                  Techniques of m i c r o s t r c                     a n a l y s i s have been employed i n d e f i n i n g coke
t y p e s and q u a l i t y f o r some t i m e .    rJ''fs              However, t h e r e h a s been l i t t l e e f f o r t ex-
pended t o determine the m i c r o s t r u c t u r e v a r i a t i o n s between samples t a k e n from v a r i -
ous l o c a t i o n s i n l a r g e coke masses o r the number of f i n g e r s t h a t should be a n a l y z e d
t o a d e q u a t e l y c h a r a c t e r i z e coke s t r u c t u r e . Coke m i c r o s t r u c t u r e d a t a have been use-
                                                                                                                      ~
f u l i n e x p l a i n i n g v a r i a t i o n s i n p h y s i c a l p r o p e r t i e s , 2 r e a ~ t i v i t y ,and b l a s t f u r n a c e
behavior4 o f v a r i o u s coke t y p e s . T h e r e f o r e , i t i s important t h a t t h e l i m i t a t i o n s and
r e p r o d u c i b i l i t y of m i c r o s t r u c t u r e a n a l y s i s be determined i f coke m i c r o s t r u c t u r e analy-
ses a r e t o b e used t o q u a n t i t a t i v e l y c h a r a c t e r i z e coke q u a l i t y and b e h a v i o r . Conse-
q u e n t l y , t h i s i n v e s t i g a t i o n w a s i n i t i a t e d t o d e t e r m i n e t h e l o c a t i o n and number of coke
f i n g e r s needed t o c h a r a c t e r i z e t h e m i c r o s t r u c t u r e of coke produced i n a 750-pound
p i l o t coke oven and t o e v a l u a t e o u r p r e s e n t coke sampling procedures.

                  A s p a r t o f The Youngstown Sheet and Tube Company's program of coke e v a l u a -
t i o n , two d u p l i c a t e c h a r g e s o f 1 0 0 p e r c e n t h i g h v o l a t i l e A bituminous c o a l were car-
bonized f o r t h i s i n v e s t i g a t i o n . Samples were c o l l e c t e d from each c h a r g e a c c o r d i n g t o
a s t a t i s t i c a l l y designed sampling plan.                The coke f i n g e r samples were mounted and
p o l i s h e d and t h e i r m i c r o s t r u c t u r e determined u t i l i z i n g a s i x s p i n d l e i n t e g r a t i n g s t a g e .
The r e s u l t a n t m i r r o s t r u c t u r e d a t a were t h e n s t a t i s t i c a l l y e v a l u a t e d .

PREPARATION OF COAL FOR CARBONIZATION

                  I n order t o provide c o a l f o r two d u p l i c a t e c h a r g e s , a b u l k sample (1500
l b s . ) of h i g h v o l a t i l e A bituminuus c o a l was c o l l e c t e d . This bulk sample (1" x 0"
f r a c t i o n ) w a s p u l v e r i z e d t o a p p r o x i m a t e l y 82 p e r c e n t minus 1/8" (Table I) i n a
Pennsylvania Tvpe C r e v e r s i b l e hammer-mill-impactor.                              A l l of t h e p u l v e r i z e d c o a l was
t h e n blended i n a Model GD. P a t t e r s o n - K e l l y , 30 c u b i c f o o t c a p a c i t y twin s h e l l b l e n d e r
f o r two h o u r s . After homogenization of t h e c o a l , samples were removed f o r s c r e e n and
chemical a n a l y s e s . P r i o r to withdrawing t h e c o a l f o r c a r b o n i z a t i o n , t h e b u l k d e n s i t y
and m o i s t u r e were a d j u s t e d and t h e c o a l was blended f o r a n a d d i t i o n a l hour.

CARBONIZATION

                   D u p l i c a t e c a r b o n i z a t i o n t e s t s were made i n a Bethlehem t y p e p i l o t coke oven
h a v i n g a coking chamber 36 i n c h e s long, 18 i n c h e s wide, and 36 i n c h e s h i g h . To i n s u r e
d u p l i c a t i o n of t h e s e t e s t s , the oven was s t a b i l i z e d f o r 24 h o u r s b e f o r e each c h a r g e .
A t c h a r g i n g t i m e , a 750-pound sample of c o a l was withdrawn from t h e b l e n d e r and placed
i n t h e oven. P e r t i n e n t c a r b o n i z a t i o n d a t a f o r these oven tests are g i v e n i n Table I.

SAMPLING PROCEDURE AND EXPERIMENTAL DESIGN OF SAMPLING PLAN

                 A sampling p l a n was s e l e c t e d i n o r d e r t o p r o v i d e d a t a f o r an a d e q u a t e ap-
p r a i s a l o f t h e m i c r o s t r u c t u r e of t h e r e s u l t a n t coke, as w e l l as p r o v i d i n g d a t a f o r a

*   See References.
                                                                       55
    comprehensive s t a t i s t i c a l e v a l u a t i o n . Although twelve o r i e n t e d samples and one quench
    c a r "grab" sample were c o l l e c t e d from each charge, only s i x o r i e n t e d samples and t h e
    quench c a r sample were examined f o r each charge. This procedure w a s followed s i n c e it
    was believed t h a t one s a m p l e from a p a r t i c u l a r l o c a t i o n on t h e f i x e d w a l l would b e t h e
    mirror image of t h e one immediately a c r o s s from i t on t h e movable w a l l o r v i c e v e r s a .
    The a r e a s from which t h e samples were taken a r e shown on Figure 1. The remaining
    twelve samples were r e t a i n e d a s r e s e r v e samples f o r a d d i t i o n a l s t u d i e s .   The coke s i d e
    and push s i d e samples were p u l l e d from t h e charge with s t e e l tongs a f t e r t h e "horseshoe"
    had been r a i s e d . The c e n t e r samples were c o l l e c t e d a f t e r h a l f of t h e c h a r g e had been
    pushed from t h e oven. Each coke f i n g e r was immediately water quenched and l a b e l e d . The
    quench c a r s a m p l e was c o l l e c t e d a f t e r t h e e n t i r e charge had been pushed and quenched.

                     Depending on viewpoint, t h e experimental d e s i g n of t h e sampling p l a n can b e
I   considered e i t h e r as (1) a f u l l 3 x 2 x 2 f a c t o r i a l with , r e p l i c a t e s , o r as (2) a f r a c -
    t i o n a l 3 x 2 x 2 x 2 f a c t o r i a l with replicates.                   The reason f o r t h e above d i f f e r e n c e
    depends on whether one c o n s i d e r s t h e l o c a t i o n of "mirror image'' coke f i n g e r s as a rep-
B
    l i c a t i o n o r a s a f a c t o r . This l o c a t i o n r e f e r s t o whether t h e coke f i n g e r sample w a s
    taken from t h e " f i x e d w a l l " or "movable wall" s i d e of t h e oven. The above considera-
    t i o n was only of secondary importance i n t h e i n i t i a l a n a l y s i s s i n c e samples had been
    taken f o r t h e f u l l 3 x 2 x 2 x 2 f a c t o r i a l . However, only h a l f of t h e o r i g i n a l samples
    were microscopically analyzed f o r t h e i n i t i a l a n a l y s i s but t h e o t h e r h a l f can be a n a l y -
    zed a t a l a t e r d a t e i f i t should prove s t a t i s t i c a l l y necessary t o d o so. Thus, the
    i n i t i a l a n a l y s i s d i s t i n g u i s h e s t h e confounded e f f e c t of charge and oven s i d e r a t h e r t h a n
    t h e independent e f f e c t of each. The f a c t o r s r e f e r r e d t o i n t h e 3 x 2 x 2 x 2 f a c t o r i a l
    a r e (1) oven l e n g t h l o c a t i o n a t t h r e e l e v e l s , ( 2 ) oven h e i g h t l o c a t i o n a t two l e v e l s ,
    (3) oven charge a t 2 l e v e l s , and (4) oven s i d e l o c a t i o n a t two l e v e l s . The experiment
    was designed t o s a t i s f y two o b j e c t i v e s :

                   1.    To determine t h e i n h e r e n t e r r o r s of t h e v a r i o u s measurement c a t e g o r i e s
                         a s s o c i a t e d with a microscopic a n a l y s i s of coke.

                   2.    To determine whether sampling e r r o r s were a t t r i b u t a b l e t o oven l o c a t i o n
                         and t o determine i f t h e p r e s e n t sampling procedures are adequate.

                      With r e s p e c t t o t h e f i r s t o b j e c t i v e , it was necessary t h a t a r e p l i c a t e t r a n -
    s e c t b e made on each coke f i n g e r , such t h a t an adequate estimate of the " w i t h i n coke
b
    f i n g e r " v a r i a b i l i t y could be obtained. Although only 12 coke f i n g e r samples were analy-
    zed, a t o t a l of 24 t r a n s e c t s were taken by making two independent t r a n s e c t s p e r coke
    f i n g e r . Thus, t h e "within coke f i n g e r " v a r i a b i l i t y of each of t h e c a t e g o r i e s i s based
    on 12 degrees of freedom and can be considered a s t h e pooled = t h i n v a r i a n c e of t h e s i x
    l o c a t i o n s and t h e two oven charges.

                      With r e s p e c t t o t h e second o b j e c t i v e , i t was necessary t h a t samples be taken
    a t v a r i o u s l o c a t i o n s w i t h i n t h e oven and a l s o from more than one oven charge, such t h a t
    i t would be p o s s i b l e t o determine whether d i f f e r e n c e s due t o oven l o c a t i o n were inde-
    pendent of t h e oven charge. Since two t r a n s e c t s per coke f i n g e r were n e c e s s a r y t o
    s a t i s f y t h e f i r s t o b j e c t i v e and two oven charges were a l s o necessary, i t w a s f e l t t h a t
    only six oven l o c a t i o n s could be i n c o r p o r a t e d i n t o t h e p l a n because of t h e t i m e involved
    i n making t h e i n d i v i d u a l t r a n s e c t s . For t h i s reason, t h e s i x oven l o c a t i o n s were chosen,
    such t h a t they would r e f l e c t l a r g e r a t h e r than small l o c a t i o n d i f f e r e n c e s and a l s o pro-
    v i d e a n adequate r e p r e s e n t a t i o n of t h e e n t i r e oven. The oven was d i v i d e d i n t o a c r o s s
    s e c t i o n of t h r e e v e r t i c a l and t h r e e h o r i z o n t a l p l o t s f o r a t o t a l o f n i n e p l o t s , b u t only
    t h e t o p t h r e e and t h e bottom t h r e e p l o t s were used i n t h e plan f o r a t o t a l of s i x samples
    p e r charge. The samples were t h e n taken a t random from somewhere w i t h i n each of t h e s e
    s i x l o c a t i o n s f o r each of t h e two charges.

                      The d a t a were analyzed by u s e of t h e a n a l y s i s of v a r i a n c e t e c h n i q u e , such t h a t
    t h e v a r i o u s sources of v a r i a b i l i t y could be d i s t i n g u i s h e d and compared.
                                                                     56-
                    The .05 s i g n i f i c a n c e level w a s used throughout t h e a n a l y s i s t o determine
whether observed d i f f e r e n c e s were "real" or n o t . For t h e purpose of t h i s r e p o r t , a
' ' r e a l " d i f f e r e n c e i n d i c a t e s t h a t t h e r i s k of making an i n c o r r e c t d e c i s i o n based on
t h i s s i g n i f i c a n c e l e v e l would b e f i v e t i m e s i n 100.

SAMPLE PREPARATION

                 A s e c t i o n one-half i n c h t h i c k was c u t from t h e c e n t e r through t h e e n t i r e
l e n g t h of each f i n g e r . I n a l l c a s e s , t h e f u l l l e n g t h o f e a c h f i n g e r (approximately
n i n e i n c h e s ) , from t h e c a u l i f l o w e r t o t h e tar end w a s maintained. The width of t h e
f i n g e r s v a r i e d from two t o t h r e e i n c h e s . To f a c i l i t a t e ease of handling, mounting,
and p o l i s h i n g , t h e 9-inch s l a b s were c u t i n h a l f .       These s e c t i o n s , each r e p r e s e n t a -
t i v e o f 1 / 2 f i n g e r , were t h e n p l a c e d i n molds, impregnated w i t h a n epoxy r e s i n , and
polished for microstructure analyses.                                                                                                             i


ANALYTICAL PROCEDURES

                    A L e i t z Ortholux microscope ( F i g u r e 2) equipped w i t h a L e i t z six s p i n d l e
i n t e g r a t i n g s t a g e , c r o s s h a i r , and a n o c u l a r micrometer was employed i n t h e s e micro-
s t r u c t u r e a n a l y s e s . A l l o f t h e measurements were c a r r i e d out a t 160X magnification.
Four t r a n s e c t s covering t h e e n t i r e l e n g t h , from t h e c a u l i f l o w e r t o t h e t a r end, were
completed on a s i n g l e s u r f a c e o f each f i n g e r . Each t r a n s e c t was o r i e n t e d perpendicu-
l a r t o t h e c a u l i f l o w e r o r t a r end, depending upon which h a l f was being examined.
During t h e f i r s t t r a n s e c t , t h e p o r e s which f e l l w i t h i n f i v e a r b i t r a r i l y chosen s i z e
c a t e g o r i e s were recorded on f i v e o f t h e s p i n d l e s . The s i x t h s p i n d l e was used t o re-
c o r d t h e t o t a l c e l l w a l l a r e a t r a n s v e r s e d during t h e t r a n s e c t . A t t h e end o f t h e
i n i t i a l t r a n s e c t , the specimen w a s r e t u r n e d t o the o r i g i n a l s t a r t i n g p o s i t i o n . A
s i m i l a r t r a n s e c t was t h e n completed over t h e same a r e a , and t h e c e l l w a l l s i z e s were
d i f f e r e n t i a t e d and t h e t o t a l s p a c e occupied by p o r e s was recorded on t h e s i x t h spin-
d l e . T h i s procedure w a s r e p e a t e d twice on each f i n g e r . The a r b i t r a r i l y chosen cate-                                i
g o r i e s ( T a b l e 1 1 ) were s e l e c t e d from t h o s e p r e s e n t e d by Abramski and Mackowsky.'                The
a v e r a g e c e l l w a l l t h i c k n e s s and p o r e diameter c a l c u l a t i o n s (Table 1 1 a r e t h o s e pro-
                                                                                                         1)
posed by Daub' and are based on t h e s u p p o s i t i o n t h a t t h e t r u e average f o r any of t h e
c a t e g o r i e s approaches t h a t o f t h e mid-point of t h e p a r t i c u l a r c a t e g o r y i n q u e s t i o n .
Although t h e a u t h o r s have n o t completed a s t a t i s t i c a l c o n f i r m a t i o n of t h i s assumption,
they do f e e l i t i s a r e a s o n a b l e e s t i m a t e o f t h e average. The d e n s i t v values are ex-
                                                                                      I                                                           I
                                                                                                                                                  .
p r e s s e d i n t e r m s of t h e r a t i o o f t h e volume per c e n t of p o r e s t o c e l l w a l l s i n t h e
coke.

RESULTS AND DISCUSSION

                 I n Table I, t h e c a r b o n i z a t i o n d a t a f o r both c h a r g e s i n d i c a t e that t h e c o a l
c h a r g e s were s u b j e c t e d t o e s s e n t i a l l y i d e n t i c a l coking c o n d i t i o n s . The thermocouple
r e a d i n g s (Tables I V , V) t a k e n a t charging and pushing t i m e do e x h i b i t some v a r i a t i o n .
However, t h e s e temperature d i f f e r e n c e s are normal f o r t h e oven i n q u e s t i o n , and ovens
of t h i s s i z e and type. The s t a t i s t i c a l e v a l u a t i o n p r e s e n t e d h e r e i n h a s n o t included
t h e s p e c i f i c e f f e c t o f temperature v a r i a t i o n . However, it would be p o s s i b l e i n fu-
t u r e work t o determine s t a t i s t i c a l l y t h e e f f e c t s of temperature v a r i a t i o n and oven
l o c a t i o n on coke m i c r o s t r u c t u r e by an a n a l y s i s o f c o - v a r i a n c e of t h e s e f a c t o r s .

                   A h i g h v o l a t i l e A bituminous c o a l w a s s e l e c t e d f o r t h i s study because pre-
v i o u s s t u d i e s have shown t h a t t h i s rank o f c o a l would produce a coke possessing con-
s i d e r a b l e v a r i a t i o n i n m i c r o s t r u c t u r e . The a u t h o r s b e l i e v e t h a t t h e v a r i a t i o n i n t h e
m i c r o s t r u c t u r e of t h i s coke t y p e would be g r e a t e r than t h a t obtained on coke from
o t h e r c o a l s used a t our Company coke p l a n t s . I n g e n e r a l , h i g h e r rank m e t a l l u r g i c a l
c o a l s produce cokes w i t h l a r g e r p e r c e n t a g e s of c e l l w a l l s and p o r e s p e r u n i t a r e a and i t
i s r e a s o n a b l e t o assume t h a t t h e degree o f r e l i a b i l i t y would i n c r e a s e with i n c r e a s i n g
rank o f t h e c o a l . T h i s o b s e r v a t i o n h a s been confirmed i n our l a b o r a t o r y and i s based
                                                                       57
on frequency measurements of c e l l w a l l s and pores i n cokes produced from v a r i o u s ranks
of coal.

               I n Table V I , t h e v a r i a b i l i t y l i m i t s a t t h e 95 p e r c e n t confidence l e v e l f o r
t h e c e l l w a l l and pore diameter c a t e g o r i e s are given. In a d d i t i o n , t h e l i m i t s a r e
given f o r t h e average c e l l w a l l t h i c k n e s s , average p o r e d i a m e t e r , and d e n s i t y measure-
ments. The "within f i n g e r " v a r i a b i l i t y c o n s i s t s of t h e i n h e r e n t v a r i a b i l i t y o f t h e
material, plus the analytical variability.

                The w i t h i n v a r i a b i l i t y l i m i t s l i s t e d f o r t h e 95 p e r c e n t confidence l e v e l
a r e t h e l i m i t s developed f o r comparison o f i n d i v i d u a l f i n g e r s , each of which was t r a n s -
versed twice. The "within f i n g e r " v a r i a b i l i t i e s o f t h e v a r i o u s measurement c a t e g o r i e s
were s t a t i s t i c a l l y compared, and i t w a s found t h a t :

                1.    The w i t h i n v a r i a b i l i t y of t h e t h r e e c e l l w a l l c a t e g o r i e s o f 0.1 t o 0.2 nun,
                      0.2 t o 0.5 mm, and +0.5 mm d i d n o t d i f f e r s i g n i f i c a n t l y among themselves.
                      A l s o t h e t h r e e pore diameter c a t e g o r i e s of 0.2 t o 0.5 nun, 0.5 t o 1.0 mm,
                      and +1.0 mm d i d n o t d i f f e r s i g n i f i c a n t l y among themselves. It i s a l s o
                      i n t e r e s t i n g t o n o t e t h a t t h e r e w a s no s i g n i f i c a n t d i f f e r e n c e between
                      t h e s e c e l l w a l l s and pore diameter c a t e g o r i e s .

                2.    The two c e l l w a l l c a t e g o r i e s of -0.05 mm and 0.05 t o 0.10 mm d i d n o t
                      d i f f e r s i g n i f i c a n t l y from each o t h e r n o r from the two pore diameter c a t e -
                      g o r i e s of -0.1 mm and 0.1 t o 0.2 mm which a l s o d i d n o t d i f f e r s i g n i f i -
                      c a n t l y from each o t h e r .

                3.    I n comparing t h e c a t e g o r i e s i n 2 above, t h e -0.05 mm c e l l w a l l s and b o t h
                      o f t h e p o r e diameter c a t e g o r i e s were s i g n i f i c a n t l y d i f f e r e n t a t t h e .05
                      s i g n i f i c a n c e l e v e l from a l l t h e c a t e g o r i e s i n 1 above. However, t h e
                      0.05 mm t o 0.10 mm c e l l w a l l s were only s i g n i f i c a n t a t t h e .10 l e v e l
                      from t h e c a t e g o r i e s i n 1 above, which would n o t b e c o n s i d e r e d s i g n i f i c a n t
                      i n t h i s analysis.

                 Even though the a n a l y t i c a l v a r i a b i l i t y w a s n o t s e p a r a t e d o u t o f t h e "within
f i n g e r " v a r i a b i l i t y , i t i s b e l i e v e d t h a t i t would be much s m a l l e r t h a n t h e "within"
l i m i t s . V a r i a t i o n s due t o t h e p o s i t i o n i n g o f t h e t r a n s e c t on t h e coke f i n g e r s were
noted, b u t i t w a s n o t s e p a r a t e d o u t i n these s t a t i s t i c a l a n a l y s e s .

                   The v a l u e s l i s t e d under " t o t a l v a r i a b i l i t y " are t h e l i m i t s o f r e p r o d u c i b i l -
i t y t h a t would be obtained i f a completely random f i n g e r were analyzed w i t h o u t any
knowledge of i t s o r i g i n a l p o s i t i o n i n t h e oven o r t h e charge from which i t was sampled.
These l i m i t s a r e much g r e a t e r than t h o s e given f o r t h e " w i t h i n f i n g e r " v a r i a b i l i t y .
T h e r e f o r e , i t i s important t h a t t h e m i c r o s c o p i s t r e a l i z e t h a t t h i s v a r i a b i l i t y e x i s t s
when m i c r o s t r u c t u r e a n a l y s e s are completed on a completely random, p i l o t oven f i n g e r .
The degree of r e p r o d u c i b i l i t y i s reduced markedly when such a f i n g e r i s analyzed. It
i s a l s o i n t e r e s t i n g t o n o t e t h a t f o r t h e two c e l l w a l l c a t e g o r i e s o f 0.05 mm t o 0.10 nun
and 0.1 mm t o 0.2 mm, t h e sampling v a r i a b i l i t y due t o oven l o c a t i o n and charge was n o t
s i g n i f i c a n t l y d i f f e r e n t from t h e v a r i a b i l i t y w i t h i n a s i n g l e coke f i n g e r . This degree
of homogeneity was not found t o e x i s t i n any o f t h e o t h e r c a t e g o r i e s .

                I n Table V I I , t h e mean v a l u e f o r t h e twelve f i n g e r s t a k e n from both charges
a r e compared t o t h e mean v a l u e f o r v a r i o u s l o c a t i o n s i n t h e oven. The average pore
diameter f o r t h e top f i n g e r s was s i g n i f i c a n t l y l a r g e r t h a n t h a t of t h e bottom f i n g e r s .
The percentages of pores i n t h e -0.1 mm, 0.1 t o 0.2 mm, and 0.2 t o 0.5 mm c a t e g o r i e s
were found t o be s i g n i f i c a n t l y s m a l l e r i n t h e samples from t h e t o p of t h e oven a s com-
pared t o t h e samples from t h e bottom (Figure 3 ) . For t h e +1.0 mm pore diameter c a t e -
z o r y , t h e samples from t h e t o p o f t h e oven had a s i g n i f i c a n t l y l a r g e r percentage than
t h o s e from t h e bottom.           Although t h e 0.5 t o 1.0 nun c a t e g o r y had a l a r g e r percentage
                                                                       58
f o r t h e t o p samples t h a n t h o s e from t h e bottom, t h i s d i f f e r e n c e was n o t s u f f i c i e n t l y
l a r g e t o be termed s i g n i f i c a n t . Although t h e h e i g h t i n t h e oven had s i g n i f i c a n t and
marked e f f e c t s on t h e pore diameter measurements, t h e h e i g h t i n oven was found t o have
l i t t l e o r no s i g n i f i c a n t e f f e c t s on t h e cell w a l l measurements (Figure 3).

                    The l o w d e n s i t y v a l u e s f o r t h e top f i n g e r s a r e d i r e c t l y r e l a t e d t o t h e i n -
c r e a s e i n t h e percentage of l a r g e p o r e s and t o t a l a r e a occupied by pores. A h i g h l y
s i g n i f i c a n t d i f f e r e n c e was found between t h e d e n s i t y of t h e t o p and bottom samples.
The d e n s i t y i s expressed i n terms of t h e r a t i o of t h e volume per c e n t of pore space
t o t h a t occupied by c e l l w a l l s .             The i n c r e a s e i n p o r e diameter and l a r g e r p o r e s may be
r e l a t e d t o a d e c r e a s e i n b u l k d e n s i t y of t h e c o a l a t t h e top of t h e oven. The loosely
packed c o a l would permit t h e f o r m a t i o n of f r o t h y coke. It is less r e s t r i c t e d i n t h e
p l a s t i c s t a t e , and gas e v o l u t i o n would proceed more f r e e l y i n t h e upper p o r t i o n of t h e
charge than a t t h e bottom. These d a t a a l s o show t h a t a given c o a l may produce a coke
w i t h markedly d i f f e r e n t m i c r o s t r u c t u r e s w i t h i n t h e same coke mass.

                   The v a r i a t i o n s i n t h e m i c r o s t r u c t u r e of t h e coke s i d e , middle, and push s i d e
samples a r e shown i n Table VI1 and i l l u s t r a t e d g r a p h i c a l l y i n F i g u r e s 4 and 5. The
i n c r e a s e i n average c e l l w a l l t h i c k n e s s toward t h e c e n t e r from both ends o f t h e oven
may be t h e r e s u l t of v a r i a t i o n s i n b u l k d e n s i t y . The c o a l i n t h e c e n t e r o f t h e oven
w w l d have a h i g h e r bulk d e n s i t y , s i n c e i t l i e s d i r e c t l y below t h e charging h o l e ,
whereas, t h e c o a l n e x t t o t h e d o o r s would have a lower bulk d e n ~ i t y . ~ Note i n Fig-                  >~
u r e 4 t h a t t h e d i s t r i b u t i o n of t h e v a r i o u s c e l l w a l l s i z e s v a r i e s from the ends t o t h e
middle f i n g e r s . It was found that t h i s d i f f e r e n c e was s i g n i f i c a n t , however, f o r only
two c e l l w a l l c a t e g o r i e s : t h e -0.05 mm and t h e 0.2 t o 0.5 mm c a t e g o r i e s . I n Figure 5
t h e percentage of p l u s 1 . 0 mm p o r e s f o r t h e end samples w a s s i g n i f i c a n t l y h i g h e r than
t h a t of t h e middle f i n g e r s . Coincident with t h e i n c r e a s e i n l a r g e r pores, i s t h e de-
c r e a s e i n d e n s i t y o f t h e end f i n g e r s (Table VII). This d e c r e a s e i n d e n s i t y i s a l s o
s t a t i s t i c a l l y a f f e c t e d by t h e h e i g h t - l e n g t h r e l a t i o n s h i p . A l l of t h e s e d a t a i n d i c a t e
t h a t c o a l bulk d e n s i t y , oven temperature and o t h e r v a r i a b l e s not c o n s i d e r e d h e r e may
a f f e c t the resultant microstructure.

                    I n Table V I 1 1 t h e m i c r o s t r u c t u r e a n a l y s e s of each charge a r e l i s t e d .             The
s i g n i f i c a n c e of t h e s e d a t a a r e as f o l l o w s :

                 1.    The mean v a l u e s f o r t h e m i c r o s t r u c t u r e a n a l y s e s of t h e s i x f i n g e r s
                       taken from each of t h e charges compared q u i t e f a v o r a b l y and d i d not ex-
                       h i b i t any s i g n i f i c a n t s t a t i s t i c a l d i f f e r e n c e s .

                 2.    Apparently t h e c a r b o n i z a t i o n c o n d i t i o n s and t h e composition of t h e c o a l
                       were s i m i l a r , as a r e s u l t r e p r o d u c i b l e d a t a were o b t a i n e d .

                 3.    Even though t h e r e a r e m i c r o s t r u c t u r e v a r i a t i o n s , t h e mean v a l u e s a r e re-
                       markably similar.

            I n order t o determine i f our p r e s e n t sampling plan was adequate t o c h a r a c t e r -
i z e a 750-pound charge, r o u t i n e "grab" samples were c o l l e c t e d and analyzed. O r pres-
                                                                                             u
e n t sampling of coke f o r m i c r o s t r u c t u r e a n a l y s i s i s as follows:

                 1.    The e n t i r e charge i s pushed and quenched.

                 2.    A s i n g l e f i n g e r e x h i b i t i n g a c a u l i f l o w e r and a t a r end and f o u r f r a c t u r e d
                       s u r f a c e s is s e l e c t e d from t h e t o p of t h e quench c a r by t h e l a b t e c h n i c i a n .

                 3.    It i s l a b e l e d and forwarded t o t h e anthracology l a b o r a t o r y f o r a n a l y s e s .

I n Table V I 1 1 and F i g u r e s 6 and 7 , m i c r o s t r u c t u r e a n a l y s e s o f t h e two "grab" samples a r e
compared t o t h e mean v a l u e s f o r t h e i r r e s p e c t i v e charges. These data show t h a t a l l
t h e v a l u e s e x c e p t t h e -0.05 mm c e l l w a l l category f o r t h e second "grab" sample, f a l l
                                                                        59
w i t h i n t h e 95 per c e n t confidence l i m i t s . This i s t r u e only i f two t r a n s e c t s a r e com-
p l e t e d on each "grab" sample. Although t h e "grab" sample from t h e second charge is
s t a t i s t i c a l l y o u t s i d e t h e v a r i a b i l i t y band i n t h e -0.05 mm c a t e g o r y by 0 . 2 1 per c e n t
t h i s could l e g i t i m a t e l y b e a d j u s t e d by t a k i n g two "grab" samples from t h e quench c a r
and making two t r a n s e c t s on each sample. The a u t h o r s f e e l t h a t t h i s minor v a r i a t i o n
i s i n s i g n i f i c a n t i n view o f t h e magnitude of t h e measurements i n v o l v e d and t h e p r a c -
t i c a l a s p e c t s of t h e s e d a t a . It i s i n t e r e s t i n g t o n o t e t h a t a n examination of t h e
f o u r sample l o c a t i o n s ( t o p middle, bottom middle, t o p push s i d e , and bottom push s i d e )
i n d i c a t e d t h a t a sample r e p r e s e n t a t i v e o f t h e charge could be o b t a i n e d a t a p o s i t i o n
somewhere w i t h i n t h e c e n t r a l t h i r d p l o t and between t h e push s i d e and middle t h i r d
p l o t s o f t h e oven. T h i s , i n c i d e n t a l l y , w a s the approximate a r e a from which t h e p r e s -
e n t "grab" sample w a s b e i n g taken. Consequently, t h e p r e s e n t method o f s e l e c t i v e l y c o l -
l e c t i n g coke samples f o r m i c r o s t r u c t u r e a n a l y s i s should be c o n t i n u e d . However, t h i s
p r e s e n t method should be checked p e r i o d i c a l l y by making a d d i t i o n a l t r a n s e c t s on samples
t a k e n from t h e s i x l o c a t i o n s as d e f i n e d i n t h e e x p e r i m e n t a l d e s i g n .

                 In Table IX t h e m i c r o s t r u c t u r e of c o k e s produced from v a r i o u s r a n k s of c o a l
and petroleum, a s w e l l a s form coke, are compared t o t h e m i c r o s t r u c t u r e of t h e h i g h
v o l a t i l e c o a l used i n t h i s s t u d y . Although t h e r e are no d i f f e r e n c e s i n c e r t a i n c e l l
w a l l and pore c a t e g o r i e s , t h e r e a r e marked d i f f e r e n c e s among o t h e r c a t e g o r i e s . There
are s i g n i f i c a n t d i f f e r e n c e s i n a v e r a g e c e l l w a l l t h i c k n e s s and a v e r a g e p o r e diameter
among t h e coke t y p e s and i n c e r t a i n c a t e g o r i e s a r e l a t i o n s h i p t o c o a l r a n k i s e v i d e n t

 U MR
S M AY

                   M i c r o s t r u c t u r e a n a l y s e s w e r e completed on 12 o r i e n t e d coke f i n g e r s c o l l e c t e d
from d u p l i c a t e p i l o t oven t e s t s of a s i n g l e h i g h v o l a t i l e A bituminous c o a l . A se-
l e c t e d "grab" sample w a s a l s o c o l l e c t e d from e a c h charge and i t s m i c r o s t r u c t u r e d e t e r -
mined. D u p l i c a t e t r a n s e c t s were made on a l l coke f i n g e r s . These d a t a show t h a t from
a p r a c t i c a l viewpoint a n a n a l y s i s of a s i n g l e s e l e c t i v e sample a d e q u a t e l y c h a r a c t e r i z e d
t h e m i c r o s t r u c t u r e of coke produced i n the 750-pound oven; The c r i t e r i o n o f adequate-
ness w a s s a t i s f i e d , from a s t a t i s t i c a l v i e w p o i n t , i n a l l b u t one o f t h e measurement
c a t e g o r i e s on one o f the oven c h a r g e s . Two s e l e c t e d "grab" samples s h o u l d completely
s a t i s f y t h e adequateness c r i t e r i o n . Even though v a r i a t i o n s were n o t e d because of s a m -
p l e l o c a t i o n i n t h e oven, t h e s i n g l e "grab" samples compare f a v o r a b l y w i t h t h e mean
values f o r the charges.



1. Krajewski, J., "Microscopic Research on t h e S t r u c t u r e o f Coke Produced from Vari-
   ous P o l i s h Coals,'' T r a n s l a t e d from P o l i s h , B u i l e t y n I n s t y t u t u Naukowo-Badawezego
   Przemslu Weglowego, Report No. 37, 1948, pp. 1-25.

2.    Abramski, C., and M. Th. Mackowsky, "Methoden und E r g e b n i s s e d e r Angewandten
      Koksmikroskopie, H. Freund, Hanbuch d e r Mikroskopie i n d e r Technik, Bank 11, T e i l I,
      Umschau Verlag F r a n k f u r t am Main, 1952; pp. 311-410.

3.    Schapiro, N., and R. J. Gray, " R e l a t i o n o f Coke S t r u c t u r e t o R e a c t i v i t y , " B l a s t
      Furnace and S t e e l P l a n t , Vol. 51, No. 4 , A p r i l 1963, p . 273.

4.    Chang, M. C . , and G. H. Denton, "Quality C o n s i d e r a t i o n s f o r F u t u r e Blast Furnace
      Coke," Paper p r e s e n t e d a t the Ironmaking Conference o f t h e M e t a l l u r g i c a l S o c i e t y of
      AIME, B u f f a l o , New York, A p r i l 1-3, 1963.

5.    Brisse, A . H., and J. G. P r i c e , " E x p l o r a t i o n s i n Cokemaking Research w i t h a F u l l
      S c a l e Coke Oven Model," Blast Furnace and S t e e l P l a n t , V o l . 4 7 , No. 1 2 , December,
      1959, pp. 1285-1290.

6.     Z u b i l i n , I. G . , " I n v e s t i g a t i o n i n t o t h e D e n s i t y D i s t r i b u t i o n of t h e Coal Charge i n
       an Experimental Large-Capacity Oven Chamber," Coke and Chemistry, USSR, No. 6 , 1 9 6 1 ,
       pp. 22-26.
                                                                   60                                                  I
                                               TABLE I   -    CARBONIZATION DATA


                                                                 1ST CHARGE                  2ND CHARGE

Net charge weight                                            665 l b s .                  673 l b s .
Net coking t i m e                                           1 8 h r s . 37 min           18 h r s . 45 min.
Oven bulk d e n s i t y                                      47.50 l b s . / F t          48.07 l b s . / F t
Kopper’s cone                                                42.0 1bs.lFt.j               40.6 lbs./Ft. 3
Per cent moisture                                            5.4                          5.5
Per c e n t p u l v e r i z a t i o n                        82.8%  -    118 inch         82.8%  -    118 inch
C o n t r o l l i n g F l u e temp.                          2460OF                       2460°F
ASTM s t a b i l i t y f a c t o r                           43.54                        42.14
ASTM hardness f a c t o r                                    55.35                        55.55




                        TABLE I1        -   SAMPLE CALCUTATIONS OF PERCENTAGES OF PORES
                                            AND CELL WALLS I N THE INDICATED CATEGORIES


         AL
   CELL W L                                                   SPINDLE VALUES
SIZE CATEGORIES                                                    (mm)                              PER CENT

  0     -  0.05     mm                                                  13.81                         15.45
0.05    -  0.1      mm                                                  16 -36                        18.31
0.1     -  0.2      mm                                                  32.54                         36.41
0.2      - 0.5      mm                                                  24.15                         27.03
        -E 0.5      mm                                                   2.50                          2.80

Total c e l l w a l l                                                   89.36                        100.00

     PORE                                                     SPINDLE VALUES
SIZE CATEGORIES                                                    (mm)                              PER CENT

  0     -  0.1    mm                                                 21.90                             8.59
0.1     -  0.2    mm                                                 18.51                             7.26
0.2     -  0.5    mm                                                 59.99                            23.55
0.5     -  1.0    mm                                                 49.93                            19.59
        +- 1.0    mm                                                104.50                            10
                                                                                                     4.1
T o t a l pore                                                      254.83                           100.00




                                                                                                                 ‘ I
                                                                    51




                                        TABLE 111- SAMPLE CALCULATIONS OF AVERAGE PORE
                                                   DIAMETER AND CELL WALL THICKNESS


                                                           SPINDLE
                      CELL WALL                            VALUES         MID POINTS           NUMBER OF
                   SIZE CATEGORIES                         0                 (MP)              CELL WALLS

                        o    -   0.05 mm                    13.81    i      0.025               552.40
                   0.05      -    .
                                 0 1 INTI                   16.36    i      0.075               218.13
                    .
                   01        -   0 2 mm
                                  .                         32.54    i      0.15                 216.93
                   0.2       -   0 5 mn~
                                  .                         24.15    6      0.35                  6.0
                                                                                                   90
                            +     0.5   mm                                                          .3
                                                                                                   33

                   T o t a l cell wall                      89.36 mm                   Total   .1059..79

                   Average cell wall t h i c k n e s s =    9*6
                                                           10593
                                                           8 . 79 =       ,084mm

                                                           SPINDLE
                        PORE                               VALUES         MID POINTS            U BR
                                                                                               N M E OF
                   SIZE CATEGORIES                         0                 (Me)                PORES

                        0   -    0 1 mm
                                  .                         21.90    i      0.05                 438.OO
              . .
                   0.1      -    0 2 mm
                                  .                         18.51   ' i     0.15                 123.40
                   0.2      -    0.5 mm                     59.99    4      0.35                 171.40
                   0.5      -    1.0 mm                     499.93          0.75                  66.57
         .
    . , ..:        .
                            + 1.0 mm                       104.50           1.50                  69.67
,    _. .              ..                                            i
                                                                            -
    .         ,

        '         " ? > t a l pore                          518
                                                           2'.3     mm                 Total     869.04

                   .:.verage pore diameter = 869.04 =         .293 mm
                                                                                                   I

                                                                                                   f




                                                         52

                         TABLE I V       -    COMPARISON OF TEMPERATURE READINGS
                                              TAKEN A T CHARGING TIME


                        1ST CHARGE                  N
                                                   2 D CHARGE        1 S T CHARGE    2ND CHARGE
THERMOCOUPLE            FIXED WALL                 FIXED WALL       MOVABLE WALL    MOVABLE WALL

                          187 O°F                    1850°F            1760'F          1760'F
                          187 0                      1860              1820            1800
                          1850                       1840              1800            1840
                          1950                       1960              1890            1900
                          19 00                      1890              1900            1880
                          out                        out               1820            1860
                          17 8 0                     1700              1860            1860
                          1860                       1840              1920            1910
                         1850                       -1880              -
                                                                       1600           -1610        A

Average                   1866OF                     1853OF            1819OF          18240F




                         TABLE V     -       COMPARISON OF TEMPERATURE READINGS
                                             TAKEN AT PUSHING TIME


                        1ST CHARGE                 2ND CHARGE        1ST CHARGE       N
                                                                                     2 D CHARGE
THERMOCOUPLE            FIXED WALL                 FIXED W L
                                                          AL        MOVABLE WALL    MOVABLE WALL       !

                          1860°F                     1800OF            1890°F          1840°F
                          2000                       1900              2070            2060
                          2020                       2020              1980            1990
                          1980                       1970              2000            1970
                          2140                       2110              2170            2150
                          out                        out        ?      2140            2100
                          1760                       1770              1940            1890
                          1980                       1840              2040            2020
                         -1930                      -1870              -
                                                                       1880            -
                                                                                       1800

Average                   1959OF                     19 10°F           2012'F          1980'F



THERMOCOUPLES
I N COKE MASS                                        1ST CHARGE                        N
                                                                                      2 D CHARGE

8 3 Fixed w a l l                                      1920°F                           1900°F
#4 M o v a b l e wall                                  1920                             1900
#5 C e n t e r                                         1890                             1870
       TABLE           -   "WITHIN FINGER" AND TOTAL VARIABILITY ERRORS AT THE 9 i
                           PER CENT CONFIDENCE LEVEL FOR ONE AND TWO TRANSECTS


      CATEGORIES                'WITHIN FINGER" VARIABILITY                     TOTAL VARIABILITY*
                                         PER CENT                                  PER CENT
      CELL W L S
            AL                 ONE TRANSECT    TWO TRANSECTS             ONE TRANSECT    TWO TRANSECTS

        - 0.05 mm                2 2.477              5.1.752                i 5.169                2 5.014
0.05    - 0.1                    +, 3.716             f 2.628                2 3.549                2 3.022
0.1     -   0.2 mm               +, 5.596             2 3.957                2 5.849                2 5.102
0.2     - 0.5     mm             2 5.553              - 3.926
                                                      +                      2 8.275                5 7.773
        + 0.5 mm                 2 5.900              5 4.172                5 6.327                f- 5.562


       PORES

        -   0.1 mm               f-   1.782           f 1.260                 2 4.933               5 4.849
0.1     -   0.2 m                5 2.777              f- 1.964                +_ 8.248              5 8.124
0.2     -   0.5                  t 5.127              +- 3.626                +_13.101              52.197
0.5     -   1.0mm                +, 6.119             2 4.327                 2 8.804               +. 8.230
        + 1.0 mm                 5 5.288              f- 3.739                522.487               222.324

Average Cell
Wall Thickness mm                      .00919              .00650                 .01554                 ,01482

Average Pore
Diameter mm                                                .01792                 .(I3957                .oas63
knsity**                                                   .0613                  .I731                  ,1673


 *    T o t a l v a r i a b i l i t y e r r o r : e x p e c t e r r o r i f a random sample i s analyzed without
      any knowledge of its o r i g i n a l p o s i t i o n i n t h e m e n .

**    R a t i o of volume p e r c e n t pore a r e a t o volume per c e n t c e l l wal        a r e a i . coke.
                                                                                                        r
                                                                64




                             T A B L E V I I - COMPARISON OF MEAN VALUES BY SAMPLE LOCATION AND
                                               CATEGORIES TO THE GRAND MEAN FOR BOTH CHARGES


                                   GRAND MEAN         TOP       BOTTOM       COKE S I D E   MIDDLE PUSH S I D E
      LATEGO2Y                F O R BOTH CHARGES    SAMPLES     SAMPLES      SAMPLES        SAMPLES SAMPLES

  CELL WALLS

           -   0.05 ITIXTI           14.96           14.57       15 34        14.16          13 71     17.00
0.05       -   0.1mm                  86
                                     1.2             18.79        84
                                                                 1.5          18 73          18.15     18.98

01
 .         -   0.2 mm                33.43           33.62       33 25-       33 86          34.02     32.42
0.2        -   0.5 ITUII             28.24            81
                                                     2.5         28 33        29 89          29.46     25.37
       + 0.5 mm                       4.75            48
                                                       .7             .3
                                                                     46         .6
                                                                               33             4.66      6.23

P e r Cent                           0.0
                                    100             lOO.00      100
                                                                 0.0         100.00         100.00    100.00

Average Cell
Wall Thicknsss mm                      0.087          0.088          0.086     0.089          001
                                                                                               .9       0.082




       -   0 1 mm
            .                        10.68            8.63       12.72        10.80          11.30      9-92
 .
01     -   0 2 mm
            .                        13.66           10.08       17.25        12.94          14.11      394
                                                                                                       1.'
02
 .     -   0.5     IIUTI             31.15           25.84       36.47        29.51          32* 71    31.24

0.5    -   1.0 mm                    24.43           2.1
                                                      55         23* 35       24.77          24.82     23 71
      + 1 0 mm
         .                           20.08           29.94       10.21        21.98          17.06      11
                                                                                                       2.9

?e? Cent                            100.00          100.00      100.00       100.00         100
                                                                                             0.0      100
                                                                                                       0.0     '




                                      0.236           0.275          0.196     0.238           .2
                                                                                              023       0.247

                                      0 h66
                                       .              0 * 398        0.534     0.471          0.486     0.441
                                                                 65




                         TABLE VIIS   -   COMPARISON OF EACH GRAB SAMPLE TO THE
                                          MEAN VALUES FOR THE RESPECTIVE CHARGES


                               MEAN                            1ST CHG.   ImAN                         2ND CHG.
                               1ST                              GRAB       2ND                           GRAB
      CATEGORY                CHARGE          LIMITS           SAMPL8     CHARGE      LIMITS           SAMPLE

     CELL WALLS

          - 0.05 mm            14.08       15.83   -   12.33    12.65     15.82    17.57   -   14.07     38;
                                                                                                        1.6:
 .5
00        -     .
               01    IIUTI     18.97       21.60   -   16.34    18.76     18.21    20.84   -   15.58    16.89
01
 .  - 0.2 mm                   34.18       38.14   -   30.22    96-21     32.67    36.63 -     28.71    35.86
0 2 - 05 m
 ..    .                       2.9
                                90        33.02    -   25.16    29.44     27.48    31.41 -     23.55    28.81

          + 0 5 mm
             .                   .8
                                36          7.85 - 0             2.94      5.82     9-99-       16
                                                                                                 .5      4.58
Per C e n t                   100.00                            0.0
                                                               100        100
                                                                           0.0                         100.00



       PORES

          -   0 1 mm
               .               10.58      11.84    -   9.32    11.14      10.74    12.00   -   9.48     9.97
01
 .    -       0.2 mm           1.1
                                36        15.57  -     11.65   12.56      13.68    15.64   -   11.72    14.87
02
 .    -        .
              05   IWI         31.92      35.55 -      2.9
                                                        82     29.68      30.42     40
                                                                                   3.5     -   2.9
                                                                                                67      30.26
 .
05    -   1.0 mm               24.41      2 . L 1-
                                           87-         20.08   24.29      24.46    2.9
                                                                                    87     -    01
                                                                                               2.3      24.35
      + 1.0 mm                 1.8
                                94        23.22    -   15.74   22.33      20.70    24.44   -   16-92     05
                                                                                                        2.5

Per C e ~ t                   100
                               0.0                             100.00      0.0
                                                                          100                          100.00

Average C e l l
..
2.aK T%ick.ess mm .059                     .0955   -   .OB25    .O92      .OB5     .OW5 - .0785         .090
                                                               66




                        TABLE I X   - VARIATION I N MICROSTRUCTURE OF INDICATED COKE TYPES.

                                             High-         Low-                     Petroleum   Form
 CATEGORY                  High V o l .   Med. V o l .   Med. V o l .   Low vo 1.     Coke      Coke     c

CELL WALLS

       - 0.05    IIUO         13.25          16.09          18.84         29.49        0.19      15.45   1



0.05   - 0.1 m                17.83          21.35          20.68         23.20        0.12      25.38

0.1    - 0.2 m               36.04           38.71          34.33         27.89        1.03     40.50

0.2    - 0.5     m            29.12          20.49          18.79         13.67        6.52      16.45

       + 0.5     mm            3.76           3.36           7.36          5.75       92.14       2.22

Per Cent                    100.00          100.00        100.00         100.00      100.00     100.00


Average C e l l
Wall Thickness nun           0.091           0.080          0.076         0.058       0.635     0.078



      -
      PORES

       -   0.1 m              10.55          17.23          15.62         23.62        1.98      23.76

0.1    -   0.2 m              13.72          16.68          21.88         24.63        3.72      29.16

0.2    -   0.5                29.97          37.66          40.09         37.20       15.03      34.91

0.5    -   1.0                24.32          19.86          17.63         10.66       17.05      12.17

       +   1.0 nun            21.44           8.57           4.78          3.89       62.22        -
Per Cent                    100.00          100.00        100.00         100.00      100.00     100.00


Average Pore
Diameter m                    0.230          0.168          0.167         0.132       0.583      0.127


Density                    0.439             0.569          0.589         0.534        1.59      0.747
( V o l . % C e l l Walls)
     V o l . % Pores
I


                                                  67




I
h




    FIGITRE 1   - SCHEMATIC OF 750 POUND WEN SHWING APPROXMATE LOCATICN OF COW3
                 FINGERS EXAMINED FRCM DWLICATE CHARGES.
                               68
                                                                   4




FIGURE   2   - PHOTOGRAPH OF MICROSCOPE AND INTEGRATING STAGE
              EMPLOYED I N MICROSTRUCTURE ANALYSES (1/4 X).
                                                     ,
              INTEGRATING STAGE ( I S ) , SPECIMEN (S) AND M I -
              CROSCOPE STAND (M).
, .




                                                                             69




      u
      ;    20
      L
      a
      a




           10




            0
                       -0.05               0.05       - 0.1       .
                                                                 01      -   0.2           0.2   - 0.5        +   0.5
                                                       call wall Categories           (m)




           30




      5
      c.

           20
      m
      a




           10




           0
                        -   01
                             .             .
                                          01      -   0.2          0.2       - 0.5         0.5   -   10
                                                                                                      .        + 10
                                                                                                                  .
                                                            Pore Categories          (m)
                FTI;IJIfk   3    -   CrMf'ARI5ON OF FTNOKUS TAKKN FROM TOP OF TIN OVEN                    TO TIIOSE TAKEN
                                     FHW BOLTOM OF OVEN FOR m I C I I A I O X S
                                                                 I
- 0.1   -    .
            01   - 0.2   -   0.2   -   0.1   I   0.5   -    .
                                                           10   I)   f   1.0   I
i
\




     40
                                                                    Wean for charge



     30




     10



'I
      0
                 - 0.05      00
                              .5    - 0.1     .
                                             01    - 0.2    02
                                                             .    - 0.5         +   0.5
                                    -11 Wall Categories (HH)


     40




     30




     10




      0         - 0.1         0.1 -  0.2     0.2-    0.5      0.5 - 1.0         + 1.0


          FIGURE 6 - COHPARISCN OF HEAN VAL=   FOR 1 S T CHARGE TO THE    HEAN VAWES FOR
                      THE SINGLE GRAB S m E TAKEN FROM T H I S CHARCE.
                                                            72                                              ‘ I




         “1
         30



3 2
g   s,   20
4   0

2-
         10




         0
                  - 0.05          0.05   - 0.1        01
                                                       .   - 0.2      0.2   - 0.5     + 0.5




                                                 POP3 categories   (nn)
              FIGURE 7   -   CWARISON    OF I(EAN VALIJES FOR ZND C H A W T TIE ‘HEMI YALIIGS FOR
                                                                           O
                             TIiE S I CPAB S W L E TAKEN F O THIS CIWGE.
                                   mE                     RM




                                                                                                    -   ’     I
                                                                   73




                  i n v e s t i g a t i o n I n t o t h e E f f e c t of P a r t i c l e Size and Apparent Bulk
                                                      Density on Coke S t r u c t u r e

             P r o f . D r . M. -Th. Mackowsky, Bergbau-Forschung GmbH, Essen-Kray, Germany


                      During t h e p a s t t h i r t y y e a r s , t h e r e nas been a g r e a t e f f o r t i n t h e
    s c i e n c e of c o a i petrograpny which nas l e d t o tne u s e of t h i s science i n t h e
    s o l u t i o n of c e r t a i n coking c o a l problems. T m s p e c i f i c works of F. L. Kuhlwein,
    E . Hoffmann, E. Hoffmann, E . B u r s t l e i n , C . Abramski, D . W . Van Krevelen, and
    many o t h e r s (1, 5 , 9, 10, I ) siiow over and over t h a t it i s d i f f i c u l t t o take
                                                 t)
    i n t o c o n s i d e r a t i o n a l l of t h e influences which a f f e c t t h e carbonization of coal.
    Amosov and Eremin, Harrison and Siiapiro, Gray and Eusner ( 2 , 7 , 16) have i n
    t n e i r work, wnich i s based upon t h e maceral a n a l y s i s of seam c o a l s , been a b l e
    t o a s c e r t a i n experimentally t h e optimum r a t i o of t h e r e a c t i v e t o i n e r t components
    i n tile c o a l rank ran;;e between 16 and 40 percent v o l a t i l e matter. TLese workers
    were a b l e t o d e r i v e a s u i t a b l e formula which w i l l allow t h e p r e d i c t i o n of tile
    coking stren&@n of a c o a l o r coal blend, i n terms of s t a b i l i t y , w i t h s u f f i c i e n t
    accuracy f o r use i n t h e p r e d i c t i o n of coke s t r e n g t h c h a r a c t e r i s t i c s of metal-
    l u r g i c a l c o a l blends. T1.e assumptions necessary f o r such a c a l c u l a t i o n were a
    constant s i z e c o n s i s t of t h e c o a l , as w e l l as a constant apparent d e n s i t y , and,
    of course, constant coking c o n d i t i o n s . However, a b i l i t y t o p r e d i c t s t a b i l i t y
    is not completely u s e f u l i n every case. I n t h e Ruhr d i s t r i c t of Germany, f o r
    exam?le, coals from numerous c o a l seams w i t h very d i f f e r e n t rank c l a s s i f i c a t i o n s
    a r e i n t n e feed a t t h e same time f r o m one shaft i n s t a l l a t i o n . Since t h e feeds
    t o such a coal product cannot be cnanged                  -        due t o o p e r a t i n g technique and raw
    m a t e r i a l s u p p l i e s - it is d i f f i c u l t t o assure a constant coke q u a l i t y .

                       I n a s i t u a t i o n such as tnat w i t h t h e R u h r Valley c o a l s , t h e question
    a r i s e s as t o how, with a given r a w .material s i t u a t i o n and tiierefore a given
    maceral conposition of a coking c o a l , t h e q u a l i t y of t h e c o a l produced can be
    iniluenced by changing t n e p a r t i c l e s i z e s t r u c t u r e and/or t h e apparent bulk
    d e n s i t y of t h e c o a l charge. Preliminary work along t h i s l i n e has been published
    by Marshall and Harrison (13). Using t h i s work as a b a s i s , d u r i n g t h e l a s t year
     e
    w :iave i n v e s t i g a t e d thoroughly t h e e f f e c t of s i z e and apparerit b . d k d e n s i t y on
i   tr?e coke s t r u c t u r e . For t!?e purposes of t n i s study, d i f f e r e n t s i z e c o n s i s t s of
    sear?. c o a l s were coked, varying t h e b u l k d e n s i t y and keeping t h e coking r a t e as
    c o n s i s t e n t as p o s s i b l e under l a b o r a t o r y conditions.

                    F i r s t , a very g r a n u l a r c o a i , with an apparent bulk d e n s i t y of 0, w a s
    ilsed. Tr:c SiLk d e n s i t y of 0 w a s assumed s i n c e , f o r a l l p r a c t i c a l purposes,
    eac:. p a i n w a s coked alone wit!iout c o n t a c t with t h e o t n e r s . I n a second s e r i e s
    of experiments, ilsind a smali coking oven developed by H. R i t t e r and G. Juranek
    I   -
             a 3 spnarent bulk d e n s i t y of approximately 0.5 was ilsed. The t h i r d s e r i e s
    ilas coked usin;; t n e d i i a t o m e t e r w i t h a very highly compressed c o a l i n which t h e
     . . a ~ e n t c:2.k d e n s i t y was at;out 1.
                                                              74



                  The experimental r e s u l t s w i l l be discussed b r i e f l y i n order t o %ow
t h a t such research can produce a worth-while complement t o tr.e work of i m o s o i
and Eremin ( 2 ) on one hand, and t o t h a t of Shapiro, Gray and Eusner (15, i6)
and Harrison ( 7 ) on t h e o t h e r hand. For t h e s i z e d c o a l s , t n e screen s i z e s of
5 t o 3, 3 t o 1, 1 t o 0.5, 0.5 t o 0.2, and minus 0.2 millimeter were used on
c o a l s from seams w i t h v o l a t i l e matter contents of from 15 t o 3 7 percent. On
t h e b a s i s of petrographic a n a l y s i s , t h e r a t i o of t h e r e a c t i v e t o i n e r t components
was calculated. The d a t a f o r a l l t h e samples examined are summarized i n Figure
1. Figure 1 shows t h a t i n o t h e r t h a n sample 1 ( w i t h 31.7 percent v o l a t i l e
m a t t e r ) , t h e r a t i o of t h e r e a c t i v e t o t h e i n e r t component i n t h e s c r e e n s i z e
5 t o 3 millimeters and t h e screen s i z e less t h a n 0.2 millimeters is approximately
equal, o r perhaps a l i t t l e l a r g e r , than i n t h e f i n e r Ei-ained m a t e r i a l . T h i s
i n d i c a t e s c l e a r l y t h a t a poorer coking c a p a c i t y i s s u r e l y not caused by maceral
composition but can only b e caused by t h e g r a i n s i z e .

                 The i n d i v i d u a l s c r e e n s i z i n g of coals of d i f f e r e n t stages o f c o a l i -
f i c a t i o n were examined when coked, and t h e proportion o f pore-showing g r a i n s
w a s determined q u a n t i t a t i v e l y . From Figure No. 2, it appears that i n t h e screen
s i z i n g of 5 t o 3 millimeters, a l l p a i n s - independent of t h e s t a g e of c o a l i -
f i c a t i o n - possessed degassing pores. However, t h e s i z e and shape o f t h e s e
degassing pores are q u i t e d i f f e r e n t i n c o a l s of d i f f e r e n t s t a g e s of c o a l i f i c a t i o n ,
as shown i n Figure No. 3. With i n c r e a s i n g f i n e n e s s of s i z e c o n s i s t , t h e propor-
t i o n of pore-showing g r a i n s becomes smaller. The decrease i n t h e pore-showing
g r a i n s is e s p e c i a l l y g r e a t i n t h e poorer coking coals (Samples 1 and 5 ) , while
t h e decrease becomes apparent i n t h e good coking coals o n l y i n t h e s c r e e n s i z e s
under 0.5 millimeters. The b a s i s f o r t h i s reduced pore s t r u c t u r e w i t h decreas-
i n g s c r e e n s i z e i s t h a t a degassing pore can only evolve i n t h e temperature
range of t h e p l a s t i c zone when t h e gas volume set f r e e b y t h e decomposition i s                                   /

l a r g e r than t h e gas volume escaping a t t h e same time from t h e i n t e r i o r of t h e
g r a i n by d i f f u s i o n . Consequently, t h e r e is an excess pressure i n t h e I n t e r i o r
of t h e g r a i n , and a t t h e same time a p r e s s u r e drop from t h e i n s i d e t o t h e o u t -
s i d e of t h e g r a i n . Since i n the smaller g r a i n s t h e d i f f u s i o n r o u t e and, t h e r e -
f o r e , t h e d i f f u s i o n r e s i s t a n c e i s smaller, fewer degassing pores w i l l result i n
small g r a i n s .

                    I n another i n v e s t i g a t i o n series, shown i n I l l u s t r a t i o n No. 4, t h e pore
count per grain and the mean pore s i z e diameter were a s c e r t a i n e d f o r each of t h e
d i f f e r e n t screen s i z e s ( I l l u s t r a t i o n No. 5). The pore count p e r g r a i n and t h e
mean pore diameter were a s c e r t a i n e d because it was thought that t h e mean pore
diameter i s not only dependent on g r a i n s i z e , b u t is p r i m a r i l y dependent upon
t h e degree of c o a l i f i c a t i o n and is, t h e r e f o r e , r e l a t e d t o t h e s o f t e n i n g c a p a c i t y
of t h e c o a l s . I n t h e smaller s c r e e n s i z e s of t h e b e s t coking c o a l s , t h e l a r g e s t
pore diameter is shown, and consequently, t h e smallest number of pores p e r
g r a i n . Therefore, pore size and pore count are not i n d i r e c t r e l a t i o n t o t h e
v o l a t i l e matter content of t h e i n i t i a l c o a l . The pore s i z e is probably dependent
upon t h e gas volume s p l i t off i n t h e p l a s t i c zone and t h e v i s c o s i t y of t h e
p l a s t i c i z e d coal, and perhaps also t h e permeability of t h e c o a l when i n a p l a s t i c
state. If these assumptions are c o r r e c t , then a low v i s c o s i t y m e l t might have a
poorer gas permeability t h a n a c o a l with a high v i s c o s i t y melt. However, t h e
work has not progressed f a r enough t o provide experimental d a t a on t n e s e assump-
t i o n s . If one were t o c o n s i d e r n o t only t h e small s c r e e n s i z e s f o r each of t h e
coals examined, b u t a l l s c r e e n s i z e s of a n i n d i v i d u a l c o a l , it appears that i n
                                                                 75



        c o a l s with 37.1 percent v o l a t i l e matter and 20.6 percent v o i a t i i e matter, trle
        mean pore diameter from t h e c o a r s e s t t o t h e f i n e s t s i z e s d e c r e a s e s approximately
\       one-half. I n c o a l s w i t h 15.1 percent v o l a t i l e matter, t h e pore diameter remains
        p r a c t i c a l l y constant, only t h e pore count p e r g r a i n is changed. On t n e otiier
        hand, i n good coking c o a l s , t h e mean pore diameter f a l l s o f f oniy from one-sixth
        t o one-tenth of t h e value of the c o a r s e s t screen s i z e . An e x p l a n a t i o n of t n i s
        phenomenon does not seem t o be p o s s i b l e on t h e b a s i s of a microscopic a n a i y s i s .
        Therefore, a systematic physical-chemical i n v e s t i g a t i o n became necessary. How-
        ever, it should be pointed out t h a t it is conceivable t h a t i n good coking coais
        i n which a r e l a t i v e l y s t r o n g degassing occurs i n the p l a s t i c zone, t h e r a t i o of
        t h e volume of r e l e a s e d gas t o t h a t c a r r i e d o f f by way of d i f f u s i o n s h i f t s more
        s t r o n g l y than i n c o a l s which have low degassing i n t h e p l a s t i c zone, and a t t h e
        same t i m e a p r o p o r t i o n a t e l y higher v i s c o s i t y of t h e p l a s t i c i z e d Coal.

                            I n o r d e r t o attempt t o e x p l a i n t h e occurrence of t h e undesirable sub-
        l i m a t i o n phenomenon i n t h e coking process, t h e i d e a of t h e s t r o n g s h i f t of t h e
        r a t i o of r e l e a s e d gas volume t o t h e d i f f u s i o n gas volume i n good coking c o a l was
        t e s t e d by coking and determining t h e mean c o a l g r a i n diameter b e f o r e and a f t e r
        coking. For t h e s e experiments, o n l y t h e screen s i z e s under 1 m i l l i m e t e r could
        be used, s i n c e only i n t h e s e s i z e s were t h e r e a s u f f i c i e n t number of g r a i n s t o
        allow a s t a t i s t i c a l e v a l u a t i o n of t h e r e s u l t i n g d a t a . The results are shown on
    I   I l l u s t r a t i o n No. 6. It must be s t a t e d , however, that i n t h e microscopic d e t e r -
        mination of t h e mean g r a i n diameter, t h e values of diameter were always t o 3
        small, s i n c e t h e c o a l g r a i n s w e r e c u t randomly and were not always c u t i n t h e
        plane of t h e l a r g e s t g r a i n diameter. However, t h e results a r e useful s i n c e t h e
        raw material and t h e end product w e r e examined b y e x a c t l y t h e same method.
        Screen a n a l y s i s d i d not e n t e r i n t o t h e question, because t h e screened m a t e r i a l s
        presented only s m a l l changes i n t h e mean g r a i n diameter, and t h e mechanical resis-
        tance of t h e swollen g r a n u l a r coked material was so low that it had t o be measured
        without screening because of t h e induced breakage by screening. I l l u s t r a t i o n
        No. 6 shows t h e v a r i a t i o n i n g r a i n diameter of t h e t h r e e screen s i z e s r e l a t e d t o
        t h e stages of c o a l i f i c a t i o n . If one d i s r e g a r d s t h e results of t h e sample with
        32.5 percent v o l a t i l e m a t t e r , it i s obvious t h a t f b r t h e g r a i n s i z e s 1 t o 0.5
        millimeter, t h e mean g r a i n diameter of t h e coke samples c l e a r l y i n c r e a s e s up t o
        t h e range of 20 percent v o l a t i l e m a t t e r and then decreased a g a i n . I n t h e f i n e s t
        screen s i z e s , it cannot be s a i d t h a t t h e r e i s a clear increase of t h e mean g r a i n
        diameter f o r t h e coke sample. T h i s d i s t i n c t behavior of t h e s c r e e n s i z e s of a
        c o a l has t h e same cause as t h e pore s t r u c t u r e , t h a t is, t h e r a t i o of gas volume
        r e l e a s e d i n a u n i t . t i m e t o t h e gas volume d i f f u s e d out i s t h e reason f o r t h i s
        phenomenon.

                         The d i f f e r e n t behavior of t h e s i z e d g r a i n s ( f o r example, t h e g r a i n
        s i z e between 1 and 0.5 millimeters) w i t h a n i n c r e a s i n g s t a g e of c o a l i f i c a t i o n ,
        i s explained i n t h e following manner. I n t h e various c o a l i f i c a t i o n s t a g e s ,
        t h e swelling of t h e c o a l caused by the pore formation i s compensated f o r by a
        shrinking phenomenon, following p l a s t i c s t a t e . A s a rough s i m p l i f i c a t i o n , it
        can be s a i d t h a t t h e s h r i n k i n g p r o p e r t y of a c o a l decreases w i t h i n c r e a s i n g
        s t a g e of c o a l i f i c a t i o n . Strong s w e l l i n g i n conjunction with a low shrinkage,
        o r after-shrinkage, leads t o a d i s t i n c t problem which can result i n t h e d i f f i -
        c u l t working of a coking oven. The decrease of bulk d e n s i t y a s s o c i a t e d w i t h a
        l a r g e r g r a i n s i z e , which is often undesirable, a f f e c t s t h e oven pressure less
        t n a n has o f t e n been supposed. It is p o s s i b l e , by t h e a d d i t i o n o f o i l t o t h e
        coal, t o raise t h e i n i t i a l value o f b u l k d e n s i t y of t h e c o a l . T h i s is e s s e n -
        t i a l l y t h e same as g r i n d i n g t h e c o a l t o a f i n e r s i z e , and w i i i lower tne o-ien
i
        pressure without t h e n e c e s s i t y of doing anything more t o t h e c o a l .
i
                                                                                                                                    1 1
                                                               76



                   I t is p o s s i b l e t h a t t h e l e s s e r shrinkage of a c o a l with a g r e a t e r
stade of c o a l i f i c a t i o n can b e explained by t h e changes i n t h e microstructure
or t n e c o a l . Through t h e i n v e s t i g a t i o n s of Hirsch (8) it is known t h a t i n
t n e c o x s e o f the second phase of t h e c o a l i f i c a t i o n , t h e s p e c i f i c concentration
and t:ie degree of o r d e r of t h e condensed r i n g systems contained i n t h e c o a l
i n c r e a s e s . This means tnat w i t h i n c r e a s i n g degree o r s t a g e of c o a l i f i c a t i o n ,
t.ie d i s t a n c e of t h e aromatic l a m e l l a from each o t h e r becomes smaller. I f t h e                                 'I
d i s t a n c e o f t h e aromatic lamella from each o t h e r is made e q u a l t o t h e t h e o r e t i -
c a l maximum shrinkage c a p a c i t y , it is comprehensible t h a t coals w i t h 20 percent
v o i a t i l e m a t t e r w i l l have less shrinkage than coals w i t h 30 percent or more
v o l a t i l e components. I n a c o a l w i t h less than 20 percent v o l a t i l e matter, t h e
volume i n c r e a s e of t h e g r a i n s of t h e 1 t o 0.5 millimeter s i z e range decreases
a g a i n i n coking, so it can b e s a i d t h a t t h e s e coals with a low swelling w i l l
o f f s e t t h e c a p a c i t y of poor a f t e r - s h r i n k a g e .

                The s t r o n g i n c r e a s e i n t h e mean g r a i n diameter o f t h e s c r e e n s i z e
1 t o 0.5 m i l l i m e t e r of a c o a l with 32.2 percent v o l a t i l e matter cannot b e
explained on the b a s i s of t h e r e l a t i o n s h i p s heretofore discussed. I n t h i s
s c r e e n s i z e , the r a t i o of r e a c t i v e t o i n e r t i s 10 t o 1, and i s e s p e c i a l l y high.
I t does n o t appear p o s s i b l e t o f i n d an explanation of t h e high volume increase
w i t h the help of a maceral a n a l y s i s . I t can be surmised t h a t i n t h i s type of
c o a l t h e aromatic lamella are b e t t e r arranged, and t h i s should manifest itself                                         1 1
i n a normally higner r e f l e c t a n c e anisotropy. This, however, could not be e s t a b -
lishea, and t h e r e must be f u r t h e r r e s e a r c h i n t o why t h e otherwise a s c e r t a i n a b l e
r e l a t i o n s h i p between t h e degree of c o a l i f i c a t i o n on t h e one hand and t h e swelling
on t h e o t h e r hand could not b e determined by comparison of t h e same p a r t i c l e
sizes   .
                 I n the second experimental s e r i e s , c o a l samples w i t h d i f f e r e n t s t a g e s
of c o a l i f i c a t i o n were a g a i n coked i n t h e experimental furnace of R i t t e r and
Juranek. For t h i s s e r i e s , b u l k d e n s i t y was held constant. Working on t h e con-
s t a n t b u l k d e n s i t y b a s i s , it was n o t p o s s i b l e t o coke t h e i n d i v i d u a l s c r e e n s i z e s
as s e p a r a t e s , but r a t h e r a m i x t u r e of t h e following composition was e s t a b l i s h e d :


                                                         Millimeters               Percent

                              Screen S i z e         -      5 to 3             -      20
                                      !
                                                     -      3 t o 1            -      30
                                     11

                                      ,              -      1 t o 0.5          -      30
                                                     -    0.5 t o 0.2          -      10
                                                     -       under 2           -      10


                   Since t h e coked sample could be sectioned as a whole, d a t a became                                                I
p o s s i b l e i n t h i s experimental s e r i e s on t h e v a r i a b l e conditions of individual,
d i f f e r e n t sized p a r t i c l e s . The r e s u l t s of the f i r s t series were confirmed
q u a i i t a t i v e l y i n t h e second series. Q u a n t i t a t i v e l y , a few noteworthy d i f f e r e n c e s
were determined. The g r e a t e r t i g h t n e s s of packing causes t h e p a r t i c l e s t o cement
to,et:?er, s i n c e t h e y tend t o s w e l l s t r o n g l y during t h e formation of t h e coke.
Cwing t o tr.is cementing, t h e p a r t i c l e s a r e l i m i t e d i n t h e i r s w e l l i n g capacity.
                                                        77


    This results i n c l e a r l y lower mean pore diameters, e s p e c i a l l y i n t h e f i n e r
    p a r t i c l e s , with a lower pore count p e r p a r t i c l e . T h i s lower p o s s i b i l i t y of
    deformation can work out favorably i n t h e r e l a t i o n of s w e l l i n g t o after-
    shrinkage. However, t h i s does not imply t h a t i n a l l cases t h e c o a l s known
    as "dangerous oven pressure producing coals" are r e l a t e d t o a l a r g e r g r a i n
    s i z e c o n s i s t because t h i s series of tests showed t h a t t h e r e i s a p p a r e n t l y no
    g r e a t e r oven pressure r e l a t e d t o a n increase of t h e mean g r a i n s i z e p a r t i c l e
    diameter. D i r e c t measurement of t h e oven pressure cannot be undertaken i n
    t h e small experimental equipment.

1                      I n t h e t h i r d experimental series, an u l t r a - h i g h t i g h t n e s s of packing
    (apparent bulk d e n s i t y about 1)was used. As before, t h e results of t h i s series
    confirmed t h e results of t h e first s e r i e s s o f a r a s t h e c o a l samples were
    examined. Q u a n t i t a t i v e l y , t h e experimental results were again d i f f e r e n t from
    t h e results of t h e f i r s t experimental series because of t h e v e r y high t i g h t n e s s
    of packing. T h e p a r t i c l e s cemented t o g e t h e r immediately a t t h e s t a r t of s o f t e n -
    ing. The pore formation set i n g e n e r a l l y only after t h i s cementing. The cement-
    i n g w a s again demonstrated t o be more i n t h e coarse p a r t i c l e s than i n t h e fine
    p a r t i c l e s . However, t h e mean pore diameter, and a l s o t h e pore count per p a r t i c l e ,
    were c l e a r l y reduced i n comparison t o those of t h e f i r s t two experimental series,
    s o t h a t one could no l o n g e r properly speak of a normal coke s t r u c t u r e , e s p e c i a l l y
    i f c o a l s of a very high o r low s t a g e of c o a l i f i c a t i o n w e r e charged. This again
    is t r a c e d back t o t h e f a c t t h a t w i t h an apparent bulk d e n s i t y as high as was used
    i n t h i s t h i r d series, t h e pore formation combined w i t h an increase i n volume of
    t h e p a r t i c l e is only p o s s i b l e if t h e whole coke b u t t o n w a s deformed. Therefore,
    an e s s e n t i a l l y higher i n t e r n a l gas pressure is necessary f o r t h e deformation of
    t h e whole sample t h a n f o r t h e deformation of a s i n g l e p a r t i c l e , or f o r t h e deform-
    a t i o n of p a r t i c l e s i n a r e l a t i v e l y loose charge ( a n apparent bulk d e n s i t y of O - S ) ,
    i n which, even a f t e r t h e cementing of t h e p a r t i c l e s t o g e t h e r , t h e r e s t i l l remains
    t h e p o s s i b i l i t y of swelling i n t h e r e l a t i v e l y l a r g e s p a t i a l voiurne.

                  I n I l l u s t r a t i o n No. 7, t h r e e cokes from t h e t h r e e experimental series
    are compared. The i l l u s t r a t i o n shows c l e a r l y t h e d i f f e r e n c e i n mean pore d i a -
    meter and t h e pore count p e r p a r t i c l e . Further, it i s apparent t h a t i n t h e very
    l o w and t h e very high b u l k d e n s i t y charges t h e r e is no normal coke s t r u c t u r e
    formed   .
                       I f conclusions usable i n p r a c t i c e a r e t o be drawn from t h e s e t h r e e
    experimental s e r i e s , one conclusion is t h a t crushing a c o a l t o o f i n e can lead
    t o a lowering of coke q u a l i t y . I n good coking c o a l , p a r t i c l e s under 0.2 m i l l i -
    meter are t o o f i n e , and w i t h poor coking c o a l s , p a r t i c l e s under 0.5 millimeter
    appear t o be t o o f i n e . A" t h e s e s i z e s , t h e pore formation necessary f o r coke
    formation is g r e a t l y reduced and i n many cases is completely absent. On t h e
    o t h e r hand, the results a l s o show that t o o high a proportion of coarse p a r t i c l e s ,
    ( p a r t i c l e s between 2 and 3 m i l l i m e t e r s ) e s p e c i a l l y w i t n a v e r y good coking coal,
    iead t o a very porous ccke whose s t r e n g t h i s not s a t i s f a c t o r y . F u r t h e r , it can
    be snown from t h e t h r e e e x p e r m e n t a l s e r i e s that a high d e n s i t y packing ( t h e
    ni;- b u i k d e n s i t y ) does not p o s i t i v e l y lead. t o an i n c r e a s e i n t h e s t r e n g t h of
    ccke, s i n c e w i t h a buik d e n s i t y of about one, a good ccke s t r u c t u r e can no longer
    be formed.




I




                                                                                                                           -   I
                                                          q-7               ._




                                                          I’
Samples                                1           2                         5     1    6-1
                               -   -          -.
Volatile Components of
Raw Material i n Weight $,         37.i            32.2   29.9   1   23.7   20.6       15.1
Water and Ash Free                                               I

      5      - 3                       6.1          3.0                      2.1        3.8
      3      -1       111111           7.3          3.8                      3.0        4.9
      1      - 0.5m                    6.7         10.1    4.3        4.9    5.2        5.3
      0.5    -   0.2 111111            5.7          4.6                      5.2        9.0

             < 0.2 mm                  3- 2         3.3                      4.3        6.1
                               -___


              Illustration No. 1. The Ratio R / I for the Coal Charge for
                 Granular Coking, Distributed According to Screen Size




 b l a t i l e Components of
 l w Materid i n Weight $,
 a                                     37.1                          23.7
 later and Ash Free

       5     - 3       UQn         100                               100

       3     - 1       mm              98                             0
                                                                     10

       1     -   0.5m                  98                            100

       0.5   - 0.2      m              62                             aa
             < 0.2 mm                  23                             30


       Illustration No. 2. Portion o f Coked Screen Sizes i n Particles With
            Degassing Pores (fusite and mineral-free coking material)
                                                                   .
                                                                  .-   .   -
I o l a t i l e Components of                                                    --       -   -1       --        -

law M a t e r i a l i n Weight $,            37.1         32.2       29.9         23.7             I        20.6     15.1
-
ister and 4sh Free
   -
       5     - 3     mm                      14                                       9                     10       10

       3     - 1     mm                       7                                       3        j             3       - 4

       1     -   0.5m                          3                                      2        1             3        2

       0.5   -   0.2 rn                       2                                       1                      1        1

             <   0.2 m                        2                                       1                      1



                   I l l u s t r a t i o n N o . 4. Pore Frequency p e r P a r t i c l e i n
                                       P a r t i c l e s With Degassing Pores




                                                                                                                            4


Water and Ash Free                                                                                                          i



                                                                                                                            i




                        I l l u s t r a t i o n No. 5.   Mean Pore Diameter i n rn
                                     81




                                                                   Sieve Size


  0.55


  0.50


  '0.45


  0.40
                                                                   1-0.5 mm

  0.35


  0.30


  0.25




                                                                   1.5-0.2   IBIII



  0.1c    '                I                 I




                                                                   : 0.2 m
                           I                 1

          1c              20                 30      ($1
                                                       I      40

          VOLATILE COMPONENTS OF VITRINITE, WATEH AND A S H FRE%


                                             Bergbau-Forschung, 1962, TR 1 1
                                                                          7


                  .
Illustration No. 6 Particle Diameter of the Granular Coking Material
I     h
      +
n
l     d
d     a
 I    FI
rl




      9
      c
      d
      c,
      (d
      d
      a
      c
      d




      a
E!    %    .
l
n     2
      d
0     v1
 I    .a
d
      r2
      k
       0




      <
 I
d
V
 ..
 0)
 N
d
n
r
 0)

3
4
-P
 k
 (d
@I
                                                          83


Untersuchungen iiber den E i n f l u B von KorngroBe und S c h u t t g e w i c h t

                                      auf d i e Koksbildung


Prof. D r . M.-Th.           Mackowsky, Bergbau-Forschung GmbH, Essen-Kray



I n den vergsnzenen 33 Jeiiren h a t e s n i c n t ~n Versuchen g e f e - l t ,
                                                                    e r
d i e j e d e u t u n g d e r ~ ~ 0 ; i l e r p e t r o g r a p h i f U Verkokungs2robleae
h e r a u s z u s t e l l e i ? . 3 s s e i I l l e r Eur 6s d i e k r b e i t e n von F. L. .3iiil-
w n i y , 3. soffmann,
 U i .                           :<.     .-:cf<:xnn, 3 . S u r s t l e i n , C. I'ora:r,ski, g:,!.
var? !:revelen u.v.a. e r i n : i e r t ( 1 , 3 , 9, 10, 19). I n d i e s e n h r b e i -
t e n z c i 2 t s i c h immer x i e d e r , d a 4 e s s e h r schirrierig i s t , d i e
B i e l f a l t d e r 3 i n f l 9 s s e i n s g e s a x t zu b e r i i c s s i c h t i g e n und dennoch
zu Klnr uberschaubaren Zrgebnissen zu k o m e n . Amosov; Eremin,
Harrison, S c h a g i r o , G-r?.y und Sw.sier (2, 7 , 16) ha'oen nun den Ver-
such u n t ernomnen, s u s ; e 3         &n          von d e r X a z e r s l a n a l y s e v e r s c h i e d e n
!o ch i n k on1t e r 3 3 z II 1
 i                              1     oh e?; d L s o 2 tirna 1 Ve r h.21 x i s v o n r e ak t i v e n
                                                                     e               t
zu i n e r t e n G e s t a i d t e i l e n in I n k o h l u n g s b e r e i c h m i s c h e n etwa
40-16           P l u c h t i g e n J e s t a n d t e i l e n e x p e r i m e n t e l l zu e r m i t t e l n una
a n s c h l i e Q e n d Forrqeln a u f s a s t e l l e n , n i t d e r e n R i l f e auch Ssi Tor-
1 e !< e v o n
 i      m         :
                  < oh 1 i is c hu.:.i, :, ? i?
                        en                        d ie lio K sf e s t i g ke i t m i t b ef r ie d iQ e n d e r
Genaui,z:ieit e r r e c h n e t - u e r d c i l kann. Bufg-und d i e s e r i r b e i t e n i s t
e s mijglich geworden, d.ie r o h s t o f f l i c h e Z u s x m e n s e t z J n g e i n e r Xoka-
kohle ohne ZusStze zu v e r l e s s e r n . V o r r a a s s e t z u c g fiir d e r a r t i g e
Berechnun,en i s t e i n k o n a t a c t e r K ~ r n u n g s a u f b a ud e r K o I d e , e i n
B o n s t a c t e s s c n 5 t t g e w i c h t mc! s e l S s t v c r s t 2 n d i i c b k o n s t s n t e Ti'er-
kokungsbedingungen , els o y l e ich'ol e ibem2e de i z zugs t e:?peratur. und
d a m i t $1e i ch b 1 i h e nd. e r L7e r i r okung s 1 r t s c iir it t , -::e nn i n i;o K s e,fe n
                          e                                 o
g l e i c h e r j.usmessun2, v o r 5!1ez gleic';,er K a m e r b r c i t e v e r k o k t ; . r ?                :i-.
                                                               84


      z a n l r e i c h e F l o z e m i t r e c h t v c r s c l i e d e n e n ! 1nkohlun;;sgrad s u f e i n e r
      S c h a c h t a n l a g e z u g l e i c l i i l l PYrderung s i n d . I h r P G r d e r a n t e i l ksnil
      a u s b e t r i e b s t e c h n i s c h e n und r o h s t o f f l i c h e n Griinden n i c h t i n w e i t e n
      Grenzen v e r a n d e r t werden, d z dann, a u l l a n g e S i c h t Sesehen, e i n e
      g l e i c h b l e i b e n d e K o k s q u a l i t 2 t n i c h t zu g z r a n t i e r e n 1 s t . 9 e i e i n e r
      d e r a r t i g e n S i t u a t i o n gevvi-mt d i e P r a g e , wie b e i gegebener r o h s t o f l -
      l i c h e r S i t u a t i o n , a l s o ;;egebeiier Yiszeralzusanmensetzung und gege-
      b e n e r inkohlungsmafiiger 'Zusmmensetzung d e r Kokskoiile d i e Koks-
      q u a l i t a t durch Veranderung d e s Kcirnungsaufbaus und d e s IjchLittge-
      w i c h t s beeinfluI3t werden kann. h h n i i c h e I d e e n wurden auch schon                                           ' I
      v o n ' X a r s h a l 1 und H a r r i s o n g e k u 8 e r t ( 1 3 ) . iius d i e s e n Grunde haben
      w i r i n den l e t z t e n J a h r e n i n verstarkter.i,,iaBe den EinfluB von
      Kornung und S c h i i t t g e w i c h t auf d i e Koksbildung u n t e r s u c h t . Zu diesem
      Zweck wurden v e r s c h i e d e n e S i e b s t u f e n o d e r auch v e r s c h i e d e n e Lor-
      nungen v o n F l o z k o h l e n i n u n t e r s c h i e d l i c h e r P a c k u n g s d i c h t e b e i
      annahernd g l e i c h e m V e r k o k u n g s f o r t s c h r i t t i m Laboratoriurnsmai3stab
                   .
      v e r k o k t 'r3ei d e r sogenannten SGracularverkokunq wurde n i t e i n e a
                                                                                                                                 'I
      S c h u t t g e w i c h t von 0 g e a r b e i t e t , d a p r a k t i s c h j e d e s K o r n , ohire d a s
      a n d e r e zu b e r i i h r e n , a l l e i n verii-okt wurde. I n e i n e r z w e i t e n ?er-
      s u c h s s e r i e wurde i n den von H. :Titter 2nd G. J u r s n e k ( 1 4 ) entwickel-
      t e n k l e i n e n Verkokungsofen b e i einem S c h u t t g e w i c h t von etma 9,5
      g e a r b e i t e t und i n d e r d r i t t e n V e r s n c h s r e i h e i n j i l a t o a e t e r I n i t
                                                                                                                                       I
      h o c h v e r d i c h t e t e n Kohlen, a e r e n S c h u t t g e w i c h t etwa b e i 1 la$z.

      In f o l g e n d e n s o l l e n niln k u r z d i e T e r s u c h s e r g e b n i s s e bcs:;rozcen
      werden, um zu z e i g e n , d a 5 d e r z r t i g e Untersuchungen g e g e b e n e n f i l l s
      e i n e w e r t v o l l e 3rgg.nzung d e r j i r u e i t e n von !iaosov unci xremin ( 2 )
      e i n e r s e i t s und von S c h a p i r o , ,>ray, Zusner ( 1 5 , 1 6 ) und H a r r i s o n (7)
      a n d e r e r s e i t s d a r s t e l l e n kaniien. Y i i r d i e >ranularverxolcuns vwrden
                                                                                                                                 ' I
      d i e S i e b s t u f e n 5-3, 3-1, 1-0,5, 0,5-0,2 und un'ler 0 , 2 r m 8 . u ~                                   FlBzen
      zwischen 37-1 5                 F l i i c h t i g c n 3 e s t a n d t e i l e n u n t e r s u c h t . k u f p u n d von
' ,   M a z e r a l a n a l y s e n wurde d e r :;uoti,ent r e a k t i v e zu i n e r t e n B e s t a n d t e i -
      l e n e r r e c h n e t , d e r f u r e l l e u n t e r s u c h t e n Proben i n Abb.-Nr. 1
      z u s a m m e n g e s t e l l t i s t . Die .Abb,.-Xr. 1 z e i g t , d a B abgesehen von Probe
      1 m i t 3 7 , l $ F l i i c h t i g e n B e s t z n d t e i l e n i. waf. d e r Q u o t i e n t R / I i n
      den S i e b s t u f e n 5-3 mn und u n t e r 0,2 anngihernd g l e i c h o d e r i m
    .>.
     'Pein'.        s o g a r grol3er i s t , s o d.2-13 e i n s c h l e c h t e r e s Verkokunzsver-
    !2os;en i m .Ec'ei'nkor.- s i c h e r n i c h t durch d i e -azeralzusamrr,ensetzun~
    'ue:.iirkt w i r d , sondern n u r durc!? d i e Lorngr62.e.

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    ivurden nach d e r ~ronularver~co:.ung u n t e r v e r s c h i e d e n s t e n Z e s i c h t s -
    punlrten u n t e r s u c h t . -11s 1. v!u.rde d.er i i n t e i l a n porenzeigenden
    Kornern q u a n t i t a t i v e r x i t t e l t . LAIS d e r !Yi'o.-h-.           2 g e h t h e r v o r , daR
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    r e n d s i e s i c h b e i 5 e n . g u t verkokbaren Kohlen zwischert 30 und 25 :'.
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Kohlen und v i e l l e i c h t a u c h von d e r P e r m e a b i l i t R t d e r Xohlcn i,?                        1
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k l e i n e n S i e b s t u f e n f u r a i l e u n t e r s u c h t e n PlozkoMen sondern a l l e
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dagegen v o n ' l / 6 b i s 1/16 3.es - ; i e r t e s f u r d i e grobe S i e b s t u f e . Zinc
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kokenden ,Kohlen, b e i del-len e i n e verh2ltnisriiaAig starke Entgasung
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werdender zu iiber B i f f u s i o n a b t r a n s p o r t i e r t e r Gasnenge s t g r k e r
v e r s c h i e b t a l s b e i den iiohlen' mit g e r i n g e r "ntgasung i n d e r
p l e s t i s c h e n Zone und z u g l e i c h verh%ltnisnSMig hoher V i s k o s i t a t d e r
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u n t e r 1 mn herangezogen we.r.den, da n u r b e i ihnei: e i n e a u s r e i c h e n i e
Anzahl von IGjrnern Fir d i e s t a t i s t i s c h e iiusxerturis z u r VerfGgxig
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nehuen. Zu Ihrem V e r s t B n d x i s !:.; v o r a u s g e s c k i c k t ;.!eraen, 2s.:. o s i 332
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    kainen n i c h t i n f r a g e , d:?, eininai ! - n i t i h r k l e i n e Verschiebv.c;,or ix
    m i t t l e r e n K o r n d u r c h a e s s s r n i c k t e r f a f i t werden konnen, rnct arPe?sn
    war d i e n e c h a n i s c h e , i i d . l . r s - t a ? i d s f E h i g k e i t d e s z.T. s t a r k .;eblL.'rten,
    g r a . n u l a r v e r k o k t e n X s t s r i a l s s o g s r i n s , dal! 'bei e i n e r Sj'ieburc,. zit
    e i n e r u n k o a t r o l l i e r b a r e n Z e r i l e i n e r u n g S e r e c h s e t vierden rnu.Ete. Dic
    Abb.-Br. 6 z e i g t d i e TerZnderungen d e r m i t t l e r e n Korndurchmesser ?ir
    3 S i e b s t u f e n i n Ab?.#ngig:ieit von Inkohlu>lgsgrzd. .le:.m von d e r :?robe
    m i t 3 2 , 5 % F l i i c h t i g e n d e s t ? . n d t e i l e n abgesehen w i r d , i s t f2.r d a s
    Korn 1-0,5 . f e s t z u s t e l l e n , 2.3.3 d e r a i t t l e r e Korndurchmesser der
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    v e r k o k t e n Proben n i t s-tei.,:er,aez Inlcohiungsgrad b i s i n d e n . J c r e i c h
    urn 29 5 F l i i c h t i g e S e s t z n d t e i l e d e u t l i c h z u . n i m t , rn dqcn .:vieder
    abzunehinen. ;Sei den b e i d e n f e i i l e r e n S i . e b s t u f e n k a m von e i n e r
    d e u t l i c h e n Zunahne d e s r n i t - t l 8 r e n Korndurchmessers fiir d i e v e r k o k t e n .
    "roben n i c h t mehr g e s 3 r o c h e n vierden. D i e s e s u n t e r s c h i e d l i c h e Ver-
    h s l t e n d e r S i e b s t u f e n einei- Fl"    -     3zko!ile n a t d i e g l e i c h e Urszche
    wie d i e P o r e n b i l d u n s . 3 s v!irxt s i c h a l s o auch :n_ier das V e r h a l t n i s
    von i n d e r Z e i t e i n h e i t freiv!erd.ender zu a ? ; t r s n s p o r t i e r t e r GasnecGe
    a u s . "as v e r s c h i e d e n a r t i , e r s r h e l t e n e i n e r Kornung, z . 2 . d e r
    K6rnung 1 4 , 5 nun o e i stei.;,enaer!i Inkohlunpsgrad, i s t d&urch zu
    e r k l s r e n , d a 2 i n deli             rs c h i e d e ne n I n k o hlung s b e r e i ch e n d a s ciur c 5
    d i e Porenbilduzig b e d i t? ;;lii>ei? d e r Xohle i i u n t e r s c h i e d l i c h e n
    !."&e d u r c h e i n eben.fz.iis i-1 d e r 2 l a . s t i s c h e n Zoize e i n s e t z e s d e s
    Schvilinaen k o 9 2 e n s i e r t w:ird. l a ~-             .:-o.ger Vereinfachung kenn g e s a z t
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d e r is d e r Xohle e n t h a l t e n e n Bondenslerteiz kin2syste;ce e r h o h t . Das
b e d e u t e t , dai: m i t stei;jend"ii Lnk.chlun:sg%d d e r A'ostsnd d e r
A r o m a t l a a e l l e n v o n e i n a n d e r k l e i n e r w i r d . .:lird nun d e r Bbstand d e r
A r o n s t l a i , ? e l l e n v o n c i n a d e r dern t h e o r e t i s c h iilaxiinaler, ijchwirzdverm8ger,
g l e i c h g e s e t z t , s o i s t e s ve:-staiidlic:i, dais Kohlen i n i t 20 $ Fliichti-
gen d e s t a . n d t e i l e n sc!iieciiter sch,winden 31s s o l c h e i n i t 30 5 P l i i c h t i -
geii j e s t a n d t e i l e n ode? !ne:ir. 3ali o e i Kohlen m i t weniger a l s 20 $
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w e i t e r e s so zu deuteii, dafj b e i d i e s e n Kohlen 2e.n s c h l e c h t e n S c h i n -
den a u c n e i n g ? r i n g f L i S i , < e s 3lS.hen ye:.:enii3ersteht

3 i e s t a r l r e 'VargroSerunz d e s m i t - t l e r e n i<orndurchmessers d e r d i e b -
s t u f e 1-0,5 mn der iichle iiiit 32,2 :,; Bliichtigen 3 e s t a n 3 t e i l e n l a B t
s i c h a u f g r u n d d e r d i s i u t i e r t e n ZuseLzenn5ir?c;en i c h t erK1Sren. Da i n
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s c l i e i n t e s n i c h t m8glich zu s e i n , n i t B i l f e d e r Mazeralzusasmen-
s e t z u n g e i n e Arklarun,: fu.? d i e s t a r k e Volumenzun~hnme zu f i n d e n .
Die Verautung, da15 i n d i e s e r Xoiile d i e k r o a a t l a m e l l e n o e s s e r als
normal g e o r d n e t s i n d , nG.2te sic12 i n e i n e r n o m a 1 hohen R e f l e x i o n s -
a n i s o t r o p i e gu.?ern, d i e j e d o z h n i c h t f e s t y e s t e l l t werden Irointe.
2 s nu!? d o s h a l 5 w i t e r e n 2iitersuchunzeii v o r b e h a l t e n o l e i b e n , warm
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groben Ksrnern s t Y r r c e r ~1.1~              in          x l e i n e r , . Der m i t t l e r e Porecdurch-
messer und auch d i e P o r e n z a h l j e Korn viaren jedoch i m 7 e r S l e i c h zu
denen d e r e r s t e n b e i d e n Y e r s a c h s s e r i e n d e u t l i c h r e d u z i e r t , s o da3
e i g e n t l i c h n i c h t mekr von eineia normalen kZo%sgeflig'e g e s p r o c h e n wer-
d e n k o n n t e , i n s b e s o n d e r e dcnn, !Ireni? Kohlen g e r i n g e n o d e r n o h e 3
1n.kohlungsgrades ein;.c s e t Z T ; vmrden. 3 i e s i s t darauf zuruckzuf iihren,
daB b e i e i n e r s o hohen S c h i i t t d i c h t e d i e m i t e i n e r VolumenvergroBe-
r u n g verbundene P o r e n b i l d u i i g i n clen K r r n e r n n u r d m n moglich i s t ,
wenn d e r ganze Lokskuchen d e f o r n i e r t :.lird. Dafiir i s t e i n wesent-
l i c h h o h e r e r Gasinnendruck e r f o r d e r l - i c h 21s f u r d i e Deformation
e i n e s e i n z e l n e n Kornes (tranu.lzrverkoku.ng) o d e r fiir d i e Deformation
d e r Korner i n r e l a t i v l o s e r Schiit t u n g (Kleinverkokungsofen, Schiitt-
gewicht 0 , 5 ) , - b e i d e r s e l b s t nech dem Y e r k i t t e n d e r Korner u n t e r -
e i n a r i d e r d i e N o g l i c h k e i t e i n e r J e f o r m a t i o n , in d a s v e r h a l t n i s m a Q i g
groi3e Luckenvolurnen v e r - o l e i h t . I n d e r Bbb.-Br.                       7 s i n d 3 Kokse a u s
3 V e r s u c h s s e r i e n e i n a n d e r g e g e n i i b e r g e s t e l l t Die Abbildung z e i g t
d e u t l i c h d i e U n t e r s c h i e d e iin i n i t t l e r e n Eorendurchmesser und d e r
P o r e n z a h l j e horn. : i n i e h t w e i t e r , da13 b e i zu l o s e r S c h u t t u n g
                                     . ss
u d z u holier SchGttung s i c h icein normales Koksgefsge a u s b i l d e t .
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bewiesen s e i n , d29 d i e s e an ;'lt5z,k:ohieri i!u L a 3 o r a t o r i u n e r a r b e i t e t e i
3 r z e b n i s s e s i c h fUr d i e ?KX<E      ni.itzbar       c3en l a s s e n und 2 2 2 s i =
11 in'? t nur f i k P1c zko l d ei1 E o:i5 e r i? a.iv.91 fiir :.Li s c buns e n v e r s c h i e d e ne r

Kohle art e n m i t e i n m d e r 7.7 e ai? d b f:.r s i nd  .
                               s
j i e ?L7dsfiilflrhgei? o l l t e n a e i c e n , da9 durch VerSnderung d e r ;Cots-
     1e
ko 1 1 nk 3rnun g und                  e-.un= d e r ?;ackun:;sdichte           Verbesserunzen
d e r L o k s q u e l i t 2. t o                                                               t
                                       i c i-i31e iis e nd en r ~ ht o I f Ii che n 7 e r hii 1 n i s
                                                                          s
liloglich s i n d , so d                .Leiaung v e r t r e t e n w i r d , daE d i e s e Unfer-
suc hu.ng s e r g e b n i s s e e h e ':E r t v o 1 e E r gcozung d e r Arb e i t e n von
                                                   1
.bnosov und L k e a i n ( 2 , 5) e i n e r s e i t s , und S c h a p i r o , Gray, S u s n e r
( 1 6 ) und , I a r r i s o n ( 7 ) a d e r e r s e i t s d a r s t e l l t .
                                                     92


                                             scmmuM

 1.) Abramski, C.: Die Anwendung der selektiven und petrographischen Aufberei-
     tung zur Verbreiterung der Kokskohlengrundlage und zur Verbesserung der
     Koksbeschaffenheit., Glueckauf 92; (1955) S. 25/26, 714/28

 2.) Amosov, I. L., I. V . Eremin, S. J. Sukhenko und L. S. Oshurkova: Calculation
     of Coking Charges on the Basis of Petrographic Characteristics of Coke.,
     Koks u. K M , 12 (1957) S. 9/12
               h m
 3. ) Buerstlein, E. : La preparation s e l e c t i v e e t petrographique des charbons
      en vue de ieur cokefaction., C h a l . e t I d .
                                                                   3
                                                             (1954) S. 351170
                                                             (1955) S - 14/28
 4.) Echterhoff, H. und M.-Th. MackowsJ&y: Untersuchungen ueber d i e Vorgaenge
     im Koksofen., Glueckauf    (1960) S. 618/26

 5.) Echterhoff, H. und W. Simonis: D e r E i n f l u s s des Koernungsaufbaues und der
     Fuellgewichte der Kokskohle auf' d i e Kokseigenschaften., In Druck 1963

 6 . ) Eremin, J. V.:      The Petrographic Characteristics of Coals in Relation t o
       t h e i r use i n Coking Industry., Trans. Fossil Fuel Inst. Vol. V I I I . Acad.
       S r i . USSR (1959) S. 14/20                                                                  1

 7. ) Harrison, J. A . : Coal Petrography applied t o Coking Problems., Proc. Ill.
      ~ining
           Inst., 69th year (1961),                  s   . 17/45
 8.) Hirsch, P. B.:          X-Ray s c a t t e r i n g from coals., Proc. Roy. SOC. 226 (1954)
     S. 143169

 9.) Hoffmak, E. und A. Jenkner:                   Die Inkohlung und irhr Erkennung im Mikrobild.,
     Glueckauf   (1932) S. 81/88
10.) Hoffmann, H. und F. L. Kuehlwein: Rohstoffliche und verkokungstechnische
     Untersuchungen an Saarkohlen., Glueckauf   (1935) S. 625/39, S. 657/65
11.) Mackowsky, M.-Th.:  Methode d'etude des pates a coke e t nouveaw r e s u l t a t s
     de recherches sur les problems de l a cokefraction., Ann. des Mines de
     Belgique (1962)

12.) Mackowsky, M. -Th. : Mikroskopische Untersuchungen zum Verkokungsvermoegen.,
     E r d o e l und Kohle Iz (1962) S. 441/45
                            ;
1 3 . ) Marshall, C . E. und J. A . Harrison:               Influence of "Fusain" Blends upon Coke
      Character of I l l i n o i s C o a l s . ,   Illinois Geol. Survey, Reprinted Series 1962 Q

14.) R i t t e r , H. und G. Juranek:
                                Eine neue Methcde zur Untersuchung und
     Beschreibung des Erweichungsverhaltens von Kohlen., Brennstoff -Chemic                  5
     (1960)S. 170/76
                                                     93


     is.) Schapiro, N. und R. J. Gray: Petrographic Classification Applicable t o
          Coals of a l l Ranks., Proc. Ill. Mining Inst., 68th year (1960) S. 83/97

     1 . Schqpiro, N., R.
      6)                   J. Gray und G. R. Eusner: Recent Developement i n coal
           Petrography: Blast Furnace, Coke Oven and Raw Materials., A.I.M.E. Proc.
           VOl. 20 (1961)

     17.) Spackman, W.:   The Maceral Concept and the Study of W e r n Environments as
           a Means of Understanding t h e Nature of Coal., Nw York Acad. Sci. , Ser. I1,
                                                            e
           Vol. 20, No. 5, March (1958) S. 411123

     18.) van Krevelen, D. W., B. N. M. Donaans urd F. J. Huntjens: Chemical Structure
          and Properties of C o a l . X I. Behaviour of Individual Macerals and Bleends in
                                       XI
          t h e Andibert-Arnu Dilatometer., Fuel     2
                                                    (1959) S. 165/82




      Proben                            1      2         3     4        5            6
1!    Fliicht. Best.
l     a. B i n s a t z k o h l e       37,l   32,2   29,9      23,7    20,6        15,l
j     i. Gew.-%          Waf
1



1          5 - 3
           3 - 1
                                       681

                                       793
                                               390
                                               398
                                                         2,8
                                                         390
                                                               392
                                                                56
                                                                 .
                                                                        2,1
                                                                        390
                                                                                     398

                                                                                     499

I      Of5
           1   -
               -
                   0,5 rmn
                   092    -m       I
                                       697
                                       597     4,6
                                                         6,7
                                                         4,3
                                                               4,9
                                                                .
                                                               49
                                                                         .
                                                                        52
                                                                        5,2
                                                                                     5,3
                                                                                      .
                                                                                     90
                   0,2 m           !
                                   I   3,2     393       390   3.8      4,3          6,1



Abbildung-Xr. 1 : D a s Verhiltnis R/I fur d i e Einsatzkohlen                'ZUT
                                                                               I
Granularverkokung, aufgeteilt nach Siebetufen.
                                                          94



                               PETROGRAPHIC COMPOSITION AXTI THE
                                  PLASTIC PROPERTIES OF COAL

                                                     by

                James L . Bayer, George H. Denton, and Melvin C. Chang

                               The Youngstown Sheet & Tube Co.
                               Research & Development Dept.
                               Youngstown, Ohio


                                                 Abstract*
                                                                                                                         !
                   This i n v e s t i g a t i o n w a s i n i t i a t e d t o determine t h e e f f e c t s of c o a l
petrographic composition on i t s p l a s t i c p r o p e r t i e s a s determined by d i a l a t o m e t r i c          i
and plastometric measurements. I n a d d i t i o n , the e f f e c t s of c r u c i b l e design of
t h e G i e s e l e r plastometer were i n v e s t i g a t e d i n terms of t h e i r e f f e c t on t h e
r e s u l t a n t readings. The o p t i c a l changes and r e f l e c t a n c e of the semi-coke
r e s i d u e s were determined i n o r d e r to evaluate t h e e f f e c t s of temperature on                          1
t h e petrographic components as t h e c o a l i s being carbonized. A wide range of
m e t a l l u r g i c a l coking c o a l s were evaluated i n these s t u d i e s . The r e s u l t s show
that: (1)Modifications of t h e G i e s e l e r c r u c i b l e and t e s t i n g procedures improved
t h e r e s u l t s of t h e t e s t s ; ( 2 ) The petrographic composition of t h e c o a l c o r r e l a t e s
w e l l with the p l a s t i c p r o p e r t i e s as determined by t h e modified techniques; ( 3 )
Normal ASTM Gieseler d a t a d o n o t measure t h e a c t u a l p l a s t i c p r o p e r t i e s of coals
o r coal blends; ( 4 ) Heating r a t e d r a s t i c a l l y a f f e c t s t h e behavior of t h e
petrographic e n t i t i e s d u r i n g p l a s t i c i t y t e s t s ; and ( 5) Petrographic and
r e f l e c t a n c e s t u d i e s of t h e semi-coke r e s i d u e s proved t o be u s e f u l i n explain-
i n g c e r t a i n phenomena t a k i n g p l a c e during carbonization.




                                                                                                                         J


*   Complete manuscript n o t r e c e i v e d i n time for i n c l u s i o n i n D i v i s i o n a l
                                                                                                                             1
    P r e p r i n t s . Single c o p i e s of t h e complete paper w i l l be a v a i l a b l e at t h e
    Sessions i n N e w York f o r t h o s e who d e s i r e one. Others may w r i t e t h e
    authors f o r a copy.
                                                           95


               MECHANICAL AND RELATED PROPEF?TIES OF SOME EAS!l'EPJJ               COALS

                             A. A . Terchick, R. W. Shoenberger,
                                B. P e r l i c , and L. F. DeRusha

                                   U. S. S t e e l Corporation
                                 Applied Research Laboratory
                                       Monroeville, Pa.


                 I n the mining, preparation, handling, and u t i l i z a t i o n of. coal, t h e
mechanical c h a r a c t e r i s t i c s of t h e coal influence both i t s breakage and t h e operation
of t h e equipment used. Numerous methods have been eveloped t o measure the hardness,
                                                                                 * 3
strength, and g r i n d a b i l i t y properties of c o a ~ ~ 9 ~ 9One of these methods, t h e
Hardgrove g r i n d a b i l i t y t e s t , has been widely used t o determine t h e r e l a t i v e ease
of grinding coals. This g r i n d a b i l i                        index measures the hardness, strength, and
f r a c t u r e c h a r a c t e r i s t i c s of c o a l . l , t j  Further evidence t a t t h i s empirical index
measures a physical coal property w a s proposed by B r o ~ n . ~ 7                       Consequently, t h e
Applied Research Laboratory of U. S. S t e e l determined the Hardgrove g r i n d a b i l i t y
indexes of channel samples from mines i n t h e Pittsburgh seam i n t h e Pocahontas
seam, and i n eastern Kentucky seams (High Splint seam, Winifrede seam, and C seam).
These data were obtained t o provide information for the s e l e c t i o n of face equipment
i n mining and of f a c i l i t i e s f o r the+$reparation of coal. In addition, t h e r e l a t i v e
abrasiveness, microtumbler strength, and Brabender hardness (power required i n
grinding) of each coal were determined, because these c h a r a c t e r i s t i c s should a l s o
have an important bearing on t h e s e l e c t i o n of equipment.

                This paper presents t h e data obtained from the four types of t e s t s ; t h e
r e s u l t s of each t e s t are r e l a t e d t o t h e chemical and petrographic properties of
the coals and a l s o compared with one another. I n addition, t h e paper presents a
b r i e f discussion of t h e application of mechanical properties t o t h e c o a l industry.

           The sources of t h e coal samples used i n t h i s investigation a r e l i s t e d
i n Table I. A l l samples were full-length channel samples. Tfie Mine No. A, B, C,
and D samples f r o m t h e Pittsburgh seam represent four channel samples that were
blended without crushing. The other channel samples were t r e a t e d as s i n g l e samples.
The samples, which weighed about 200 pounds each, were processed by t h e method
shown schematically i n Figure 1. A l l samples were air-dried t o about 1 percent
                                                                                1
moisture content. The proximate and sulfur analyses, l i s t e d in !Cable 1 , were
determined by A m procedures. The petrographic analyses,
                  S                                                        1,
                                                                    b l e 1 1 were conducted
according t o t h e standard method developed by U. S. Steel.6?

             The Hardgrove g r i n d a b i l i t y t e s t w s conducted according t o ASTM standard
                                                            a
Db9-51. The Hardgrove apparatus has eight 1-inch b a l l s that roll on a s t a t i o n a r y
ring and are driven by a r o t a t i n g ring above. The index represents t h e weight
of material passing 200-mesh sieve after 60 revolutions i n t h e machine. The repro-
d u c i b i l i t y of t h e index obtained on a sample should check within 2 percent.

           The Brabender hardness t e s t was condu ed i n t h e Brabender Plastograph
adapted for operation as t h e hardness                    This instrument has a cone mill
and an electrodynameter t o r o t a t e t h e grinding element. A 200-gram sample of mirius
4 mesh or 16- by 30-mesh coal was fed i n t o t h e crusher. !Be power required by t h e
crusher i n grinding t h e c o a l was recorded i n respect t o time by t h e electrodynameter

 *   See references.
++Also known a s microstrength index.
                                                                 96

i n t h e form of a diagram. The a r e a drawn i n t h i s diagram i s used as t h e hardness
inLiex, which i s expressed i n kilogrammeters. The standard d e v i a t i o n f o r t h e e n t i r e
                           +
r a n j e was found t o be - 6.5 index p o i n t s .

                 The microtumbler t e s t ( r e s i s t a n c e t o degradation b y a b r a s i o n and impact)
was conducted i n a n apparatus c o n s i s t i                   Of 2 s t a i n l e s s s t e e l t u b e s , 1 inch i n
i n t e r n a l diameter and 12 inches long. 9f': The two t u b e s a r e mounted on a frame t h a t                                  1 1
can be r o t a t e d at a constant speed. Duplicate 2-gram samples of 14- by 28-mesh c o a l
were p l a c e d i n t h e tubes with twelve 5/16-inch diameter steel b a l l s and tumbled f o r
800 r e v o l u t i o n s . The breakage was t h e n determined by a sieve a n a l y s i s and t h e
                                                     a
amount of p l u s 100-mesh m a t e r i a l w s recorded as t h e microtumbler s t r e n g t h . I n
                                                                              +
t h i s t e s t u s i n g coal, t h e s t a n d a r d d e v i a t i o n w a s - 1 . 3 index p o i n t s .

             The abrasion t e s t w a s conducted on a n apparatus c o n s i s t i n g of a mortar
t h a t holds t h e charge of coal,                            n arm assembly t o hold t h e wearing blades,
and a L r i l l p r e s s t o provide %    ::!
                                            o
                                            T
                                            at
                                             i
                                             r                   The test c o n s i s t s of r o t a t i n g t h e four
removable b l a d e s a t 1500 rpm f o r l2,OOO r e v o l u t i o n s i n a 4-kilogram sample of minus
4-mesh a i r - d r i e d c o a l . A f t e r each t e s t t h e wearing olades are thoroughly cleaned
and weighed. The weight l o s s s u s t a i n e d by t h e blades i n milligrams i s used a s t h e
index of a b r a s i o n . The s t a n d a r d d e v i a t i o n was 2 1.7 index p o i n t s over t h e range
tested.

Mechanical Tests

                 The r e s u l t s obtained from each of t h e four t e s t s used t o measure t h e
mechanical p r o p e r t i e s o f t h e c o a l a r e presented i n Table I V and compared with one
a n o t h e r i n t h e following d i s c u s s i o n .

              I n t h e Hardgrove g r i n d a b i l i t y t e s t t h e Pittsburgh-seam c o a l s showed
indexes f r o m 59 t o 63. t h e e a s t e r n Kentucky c o a l s from 41 t o 51, and t h e Pocahontas-
seam c o a l s f r o m 90 t o 105. Note t h a t t h e lower t h e index, t h e more d i f f i c u l t it i s
t o grind t i e coal        These d a t a a r e i n good agreement with t h o s e r e p o r t e d by t h e
Bureau of Ydnes.li)

                   The Brabender hardness t e s t g i v e s a measure of t h e power requirement i n
g r i n d i n g the coals; t h u s , t h e index r e p r e s e n t s t h e work done i n grinding t h e sample.
The h i g h e r t h e number t h e more power i s required t o g r i n d t h e sample. A s expected,
a n i n v e r s e r e l a t i o n s h i p e x i s t s between t h e Brabender hardness index and t h e Hardgrove
6 r i n J a b i l i t y index (Figure 2, Table I V ) .             The c o r r e l a t i o n with t h e values obtained
f r o m t h e minus 4-mesh c o a l w a s much b e t t e r than with t h o s e from t h e 16- by 30-mesh
c o a l , even though t h e Hardgrove g r i n d a b i l i t y test r e q u i r e s 16- by 30-mesh coal.
This t e s t showed t h e d i f f e r e n c e s amon;: t h e coals from t h r e e d i f f e r e n t l o c a t i o n s ,
a s w e l l a s considerable v a r i a b i l i t y within each l o c a t i o n (Figure 2 ) . This v a r i a b i l i t y
izay be s i g n i f i c a n t since t h e extreme v a l u e s ranged more t h a n would be expected by
t h e standard deviation.

                  S i n c e t h e microtumbler s t r e n g t h s of' c o a l i n d i c a t e t h e r e s i s t a n c e t o degrada-
t i o n by a b r a s i o n and impact, t h e n a t u r e s of t h i s t e s t and t h e Hardgrove test a r e very
similar. T h i s s i m i l a r i t y i s c l e a r l y shown i n t h e e x c e l l e n t c o r r e l a t i o n obtained
between t h e r e s u l t s of t h e s e two t e s t s (Figure 3 ) . Bence, t h i s t e s t can be used t o
c e l c u l a t e t h e Xardgrove g r i n d a b i l i t y index, o r v i c e v e r s a .
                                                                                                                                        I
               The r e s u l t s     t h e a b r a s i o n t e s t a r e a l s o presented i n Table IV. Comparison
w i t h t h e p r e v i o u s workP6) i s l i m i t e d s i n c e t h a t i n v e s t i g a t i o n included only one coal,
                                                                          97

    R  Pittsburgh-seam coal, i n common with t h e p r e s e n t study. However, t h e indexes f o r
    cc7:ciris c o a l s were similar. The r e l a t i o n s h i p between t h e index o l abrasion and
    jri:id?.bility i s shown i n F i g r e 4. From t h i s r e l a t i o n s h i p , t h e s e t e s t s must .be
    x n s u r i n g J i f f e r e n t p r o p e r t i e s of t h e sample. The comparison ol' t h e s e r e s a l t s W i l l
    be i i s c u s s e i f t i r t h e r h e r e a f t e r .

    F a c t o r s Affecting t h e Hardness,
    Abrasion, anti G r i n d a b i l i t y of Coal

                    Because o f t h e s i m i l a r i t y OY t h e Hardgrove g r i n d a b i l i t y , Brabender hardness,
    a n i microtumbler-strength tests, only t h e r e s u l t s r e l a t i n g t h e g r i n d a b i l i t y index
    with t h e chemical and petrographic analyses of t h e c o a l s are presented. The r e l a t i o n -
    s h i p s of' t h e index of abrasion and t h e chemical and petrographic a n a l y s e s a r e discussed
    separately.

    Hardgrove G r i n d a b i l i t y

                       F i s r e 5 shows t h e r e l a t i o n s h i p of c o a l rank (express                 y volatile-matter
    c o n t e n t ) t o t h e g r i n d a b i l i t y index. Confirming published d a t a ,                      t h e index increased
    as t h e v o l a t i l e - m a t t e r content decreased. The t r e n d i s t h e n reversed Kith c o a l s having
    v o l a t i l e - m a t t e r contents of less than 23 p e r c e n t . Since              tge    aveyage r e f l e c t a n c e of
    t h e v i t r i n o i d s c o r r e l a t e with t h e v o l a t i l e - m a t t e r content,    a similar relationship
    was obtained i n Figure 6 between t h e average r e f l e c t a n c e and t h e g r i n d a b i l i t y index.
    This r e l a t i o n s h i p OF r nk             d g r i n d a b i l i t y index may be a s s o c i a t e d with t h e p o r o ~ i t y ~ ' ~ ~
    and e l a s t i c propertiesa3J1'~ of t h e various rank c o a l s .

                      The e f f e c t of a s h content on g r i n d a b i l i t y i s shown i n Figure 7. The low-
    v o l a t i l e c o a l s tended t o become more d i f f i c u l t t o g r i n d when t h e a s h content increased.
    However, a s h content had no apparent e f f e c t on t h e g r i n d a b i l i t y of' t h e h i g h - v o l a t i l e
    c o a l s . The l o w - v o l a t i l e c o a l s are much s o f t e r or more f r i a b l e t h a n t h e h i g h - v o l a t i l e
    c o a l s and r e l a t i v e l y easy t o grind; t h e r e f o r e , an i n c r e a s e i n hard ash m a t e r i a l would
    make t h e low-volatile c o a l s h a r d e r t o grind. I n c o n t r a s t , a h i g h e r percentage of
    a s h i n t h e h i g h z v o l a t i l e c o a l s would have l i t t l e i n f l u e n c e on t h e g r i n d a b i l i t y , s i n c e
    t h e c o a l substance i s a p p a r e n t l y h a r d e r than t h e a s h . Other i n v e s t i g a t o r s reported
    t h a t a d d i t i o n s of a s h t o co Is having indexes from 60 t o 110 tended t o i n c r e a s e or
    decrease t h e index t o 75. 157 However, ash content p e r se does not e x e r t a primary
    e f f e c t on t h e r e s i s t a n c e t o grinding, because t h e t y p e oi" mineral matter i s t h e m a i n
    determining f a c t o r .

                      The e f f e c t of p e t r o s r a p h i c o n s t i t u e n t s on t h e hardness o r s t r e n g t h of
    c o a l h a s been known f o r some                                In a more r e c e n t i n v e s t i g a t i o n Xarr'
    l i s c u s s e d t h e e f f e c t s o f petrographic composition i n t h e breakage of coal.                       16Bon
    A t t h e A Z L , l 7 ) t h e t o t a l tough c o a l was r e l a t e d with t h e m i c r o t m b l e r s t r e n g t h ,
    which has been shown t o c o r r e l a t e well w i t h t h e g r i n d a b i l i t y index. Therei'ore,
    t n e summation of t h e micrinoids, r e s i n o i d s , and exinoids ( p r e v i o u s l y termed . t o t a l
    t o u & c o a l ) w a s c o r r e l a t e d with t h e Hardgrove g r i n d a b i l i t y indexes. The r e l a t i o n s h i p
    is shovr. i n F i L p - 2 b . 4. good c o r r e l a t i o n was obtained r i t h t h e h i g h - v o l a t i l e coals
     ?~r.     tils F i t t s b u r g h seam an3 e e s t e r n Kentucky, where t h e g r i n d a . b i l i t y index decreased
    as Y?ie m o u n t or mnicrinoids, exinoids, and r e s i n o i . l s i n c r e a s e d . I n t h e l o w - v o l a t i l e
    cos1 samples :'ram t'ne Pocahontas s e m , t h e g r i n d a b i l i t y index increased a s t h e s e
    mzc-rals i x r e a s e d . A n examination 0; t h e d a t a of t h e s e l o w - v o l a t i l e c o a l s (Tables
    --
    i- a n l 111) i n d i c a t e s t h a t t h o s e samples with t h e l e a s t amount 01'micrinoids,
    exi:.siis:        znd r e s i n o i d s a r e a s s o c i a t e d with t h e h i g h e s t rank (Figure 5 ) and h i g h e s t
    as? Zoritents ( ? i i u r e 7) of t h e s e l o w - v o l a t i l e coals; whereas those with t h e g r e a t e s t




I
                                                                  98

amount of micrinoids, exinoids, and r e s i n o i d s a r e a s s o c i a t e d with t h e lowest r a r k
(Figure 5 ) and lowest a s h c o n t e n t s (Figure 7). Therefore, t h e c o r r e l a t i o n cittzined
f o r t h e high-rank c o a l s is d o u b t f u l , p a r t i c u l a r l y when t h e small ransc (approximately
8 t o 1 4 p e r c e n t ) of t h e amounts of t h e s e e n t i t i e s a r e considered.
Index of Abrasion

                   The t e s t r e s u l t s i n d i c a t e d t h a t the rank o r t h e petrographic composition
o f - t h e c o a l d i d not show s i g n i f i c a n t r e l a t i o n s h i p s with t h e index of abrasion, t h e
ash o r f o r e i g n m a t e r i a l i n t h e c o a l being mainly r e s p o n s i b l e lor t h e abrasion. The
r e l a t i o n s h i p of ash content and index o f abrasion i s shown i n Figure 9. Other
i n v e s t i g a t o r s have r e p o r t e d similar conclusions .l,lo)              However, t h e d i f f e r e n c e a t t h e
same ash content l e v e l f o r c o a l of s i m i l a r c h a r a c t e r i s t i c s a r e s i g n i f i c a n t , as
i n d i c a t e d by the standard d e v i a t i o n of t h e t e s t . Additional s t u d i e s are required
t o determine t h e causes f o r t h i s v a r i a t i o n .

                 Referring t o Figure 4, t h e r e l a t i o n s h i p of t h e s e two indexes can most
l i k e l y be a s s o c i a t e d with rank f o r t h e g r i n d a b i l i t y index and ash content o r mineral
m a t t e r f o r t h e index of a b r a s i o n . For example, t h e e a s t e r n Kentucky samples possessed
t h e lowest g r i n d a b i l i t y index w i t h t h e h i g h e s t v o l a t i l e matter and tough coal, while
t h e index of abrasion of t h e s e samples was low because of t h e i r v e r y l o w a s h contents.

Application of Mechanical P r o p e r t i e s

                   A t t h e ARL the power r e q u i r e d by a mining machine t o r i p c o a l vas
qualitatively related t o                     rographic p r o p e r t i e s of t h e Pittsburgh-seam c o a l and
microtumbler ~ t r e n g t h . ~ 7 , ' @ Because of t h e e x c e l l e n t c o r r e l a t i o n between t h e
g r i n d a b i l i t y index and t h e microtumbler s t r e n g t h , t h e Hardgrove g r i n d a b i l i t y index
should a l s o show t h e power r e q u i r e d f o r mining c o a l with a continuous miner. Since
t h e petrographic analyses showed only a good r e l a t i o n s h i p with t h e g r i n d a b i l i t y index
of h i g h - v o l a t i l e A c o a l s , a d d i t i o n a l s t u d i e s would be required on higher rank c o a l s
t o determine the i n f l u e n c e t h a t t h e i r petrographic composition has on t h e s t r e n g t h
of c o a l or t h e power requirements f o r mining t h i s type of coal.

                   It is i n t e r e s t i n g . t o n o t e t h a t t h e B r i t i s h have been studying t h e
r h e o l o g i c a l behavior of c o a l t o provide b a s i c data i n t h e design of coa
machinery. "ome f b d a m e n t a l s t u d i e s have r e l a t e d c o a l 1 wing f o r c e , l 9
formation,20Y and t h e p e n e t r a t i o n r e s i s t a n c e t o a wedge'l? t o t h e s t r e n g t h p r o p e r t i e s
of t h e coal. mans came t o t h e conclusion t h a t f r i a b l e c o a l f a i l s i n s h e a r and hard
c o a l f a i l s i n t e n s i o n . His r e s u l t s i n d i c a t e t h a t blades should be kept very sharp
t o e f f i c i e n t l y plow hard c o a l , sharp blades not being so necessary f o r f r i a b l e
I n another study, t h e f r i c t i o n b ween c o a l and metal surfaces w s found t o be          a
influenced b y t h e rank of                                 The r e l a t i o n s h i p t o rank vas similar t o t h a t
obtained w i t h h e a t of wetting, Knmp hardness, compressive s t r e n g t h , t e n s i l e s t r e n g t h
i n bending and impact s t r e n g t h . Brown and Hiorns have summarized t h i s B r i t i s h work.2)

                Tnis i n v e s t i g a t i o n as w e l l as others24) i n d i c a t e t h a t t h e b a s i c information
on t h e s t r e n g t h p r o p e r t i e s should be u s e f u l i n t h e design, s e l e c t i o n , and operation
of equipment used i n t h e mining, p r e p a r a t i o n , handling, and u t i l i z a t i o n of c o a l .
Of P a r t i c u l a r i n t e r e s t i n he last-named f i e l d has been t h e study of t h e breakage
o r comminution of c 0 a 1 . ~ ' 5 1
                                                                    99

                                                            Summary

                      The t e s t r e s u l t s showed t h a t t h e Hardgrove g r i n d a b i l i t y k c e x e s 5 - ' t ? ~ ~ :
    low-volatile coals from t h e Pocahontas seam were from 90 t o 1.05, t h o s e ,L? the ?.::T--
    v o l a t i l e c o a l s from t h e P i t t s b u r g h seam f r o m 59 t o 63, and those D i t h e c o a l s oi
    e a s t e r n Kentucky from 4 t o 51. The Brabender hardness indexes ard t h e a i c r o t m L l e r
                                          1
    s t r e n g t h s of t h e s e c o a l s c o r r e l a t e d with t h e g r i n d a b i l i t y indexes. :<owever, t h e
    Brabender hardness index d i d show considerable v a r i a b i l i t y between sanples f r c c t h e
    same seam o r l o c a t i o n . The index o f abrasion appeared t o measure d i i ' f e r e n t p r o p e r t i e s
I   of t h e samples and d i d not show a s i g n i f i c a n t r e l a t i o n s h i p with t h e o t h e r indexes.

                  The rank of t h e c o a l influenced t h e g r i n d a b i l i t y index as shown i n t h e
    published d a t a . The index i n c r e a s e d as rank decreased;.but t h e t r e n d was reversed
    with c o a l s having v o l a t i l e - m a t t e r c o n t e n t s ( d r y a s h - f r e e b a s i s ) of less tham 23
    percent. The a s h content appeared t o decrease t h e index of t h e l o w - v o l a t i l e c o a l s
    but d i d not have an e f f e c t on t h e index of h i g h - v o l a t i l e c o a l s . I n c o n t r a s t , t h e
    amount of micrinoids, exinoids, and r e s i n o i d s c o r r e l a t e d w e l l with t h e g r i n d a b i l i t y
    index of t h e s e h i g h - v o l a t i l e coals, b u t t h e i r influence on t h e index of low-volatile
    c o a l i s doubtful.

                  I n t h e index of abrasion, t h e c o a l substance a p p a r e n t l y contributed l i t t l e
    t o t h e abrasion, t h e ash o r f o r e i g n m a t e r i a l i n t h e c o a l being mainly r e s p o n s i b l e
    f o r t h e abrasion.

                 Previous work a t t h e ARL had shown q u a l i t a t i v e l y t h a t t h e petrographic
    composition and microtumbler s t r e n g t h could be r e l a t e d t o t h e power r e q u i r e d by
    a continuous miner. I n t h i s i n v e s t i g a t i o n t h e g r i n d a b i l i t y index has been c o r r e l a t e d
    with both microtumbler s t r e n g t h and petrographic composition, s o t h a t t h i s index
    could a l s o be used. Additional study would be necessary f o r r e l a t i n g t h e indexes
    of high-rank coals t o a c t u a l p r a c t i c e i n t h e mine.

                        These r e s u l t s and t h o s e of o t h e r i n v e s t i g a t o r s have i n d i c a t e d t h a t b a s i c
    information on t h e mechanical p r o p e r t i e s of c o a l should be u s e f u l i n t h e design,
    s e l e c t i o n , and o p e r a t i o n of equipment i n t h e mining, preparation, handling, and
    u t i l i z a t i o n of c o a l .


                                                           References

    1. H. F. Yancey and M. R. Geer, Chemistry of Coal U t i l i z a t i o n , 1st Ed., John
       Wiley and Sons, I n c . , H. H. Lowry, Ed., N w York City, 1945, pp. 145-159.
                                                    e

    2.    H. L. Brown and F. J. Hiorns, Chemistry of Coal U t i l i z a t i o n , 2nd E d . , John
          Wiley and Sons, I n c . , H. H. Lowry, Ed., N w York City, 1963, pp. 119-149.
                                                       e

    3.    W. H. Biclrle,         "Crushing and Grinding               -A      Bibliography,         "   London:H.M.S.O.,          1953.
    4.    T. G. C a l l i c o t t , "Coal G r i n d a b i l i t y   -A       Standardized Procedure," J. I n s t .
          Fuel, Vol 29, May 1956, pp. 207-217.

    5.    R. L. Brown, "Recent Advances i n Mechanics of Coal Breakage,                                     "   B C U Mor;thiy
                                                                                                                      ~
          B u l . Vol x c I No. 9, September 1962, p. 300.
                       ;V,

    6.    N. Schapiro and R. J. Gray, "Petrographic C l a s s i f i c a t i o n Applicable t o Coals
i         of' All Ranks," Proceedings of t h e I l l i n o i s Mining I n s t i t u t e , 68th Year, 1960.
                                                       0
                                                      10

 7.   C. W. Brabender, Three Machines for t h e Testing of Coal, C. W. Brabender
                          .
      Instruments, Inc , South Hackensack, Nw Jersey, 1958.
                                              e

 8.   W. GAnder, "A Method for Determining t h e Grindability of Coal," Giuckauf,
      V o l 74, 1936, pp. 641-646.

 9.   H. E. Blayden, W. Noble, and H. L. Mley, '"Be Influence of Carbonizing Conditions
      of Coke Properties, P a r t I - Mechanical Pressure," Jour. I r o n and S t e e l I n s t . ,
      V o l 136, 1937, pp. 47-62.

10. H. F. Yancey, E.I. R. Geer, and J. D. Price, "An I n v e s t i g a t i o n of t h e Abrasiveness
    of Coal and Its Associated I m p u r i t i e s , " Mining Engineering, March 1956,
    pp. 262-268.

1 . R. F. Abernethy and E. M. Cochrane, "Free Swelling and Grindability Indexes
 1
    of United S t a t e s Coals," Bureau of Mines Information Circular 8025, 1961.

12.   F. J. Hiorns and J. Venables, "Comparison of t h e Fracture of C o a l and Other
      Non-Metallic Heterogeneous S o l i d s , " B U A Monthly Bul., V o l XXVI, No. 8,
                                                  CR
      August 1962.

13. Anon., The Ultra-Fine S t r u c t u r e of Coals and Cokes, BCURA, London, 1944,
      pp. 21-30,   118-130.

14.   D. Y. van Krevelen and J. Schuyer, Coal Science, Elsevier Publishing Company,
      Amsterdam, London, New York, and Princeton, 1957, pp. 264-273.

15. A. F i t t o n , T. H. Hughes, and T. F. Hurley, 'The Grindability of B r i t i s h Coals           -
    A Laboratory Examination, " Jour. of I n s t . Fuel, Vol 30, 1957, p. 54.

16.   J. A. Harrison,         "Application of Coal Petrography t o Coal Preparation, " AIME-ASME
      J o i n t S o l i d Fuels Conference, Pittsburgh, Pa., October 4 and 5, 1962.

17. J. T. P e t e r s , N. Schapiro, and R. J. Gray, "Know Your Coal," Trans. of AIME,
      Vol 223, 1962.

18.   N. Schapiro, R. J. Gray, and G. R. Eusner, "Recent Developments i n Coal
      Petrography," Proceedings AIME Blast Furnace, Coke Oven and Raw Materials
      Committee, V O 20, 1961.
                     ~

19.   M. J . Dumbleton, M. J. O'Dogherty, and R. Shepherd, "The E f f e c t of Blade Angle
      and Other Factors on Coal Ploughing, " Mechanical Properties of Non-Metallic
      B r t t t l e Materials, W. H. Walton, Ed., Interscience Publishers, Inc., New York,
      1958, P. 399.
20.   3. J. Xamilton and G . Knight, "Some Studies of Dust Size D i s t r i b u t i o n and t h e
      a e l a t i o n s h i p Between DUst Formation and Coal Strength," Mechanical Properties
      of Non-Netallic B r i t t l e Materials, W. H. Walton, Ed., I n t e r s c i e n c e Publishers,
      I n c . , N w York, 1958, p . 365.
                    e

21. J. Esans and S. A. F. Murrell, "The Forces Required t o Penetrate a B r i t t l e
    Material with a Wedge Shaped Tool, ' Mechanical Properties of Non-Metallic
    B r i t t l e Materials, I n t e r s c i e n c e Publishers, Inc., W. H. Walton, Ed., New York,
    1958, P . 432.
                                                                0
                                                               11

    --.
    ,>
          J . Evans, "Theoretical Aspects o f Coal Ploughing," Mechanical Properties Of
          No:1-Metallic B r i t t l e Materials, W. H. Walton, Ed., I n t e r s c i e n c e Publishers,
          InC., N w York, 1958, p . 451.
                  e

    23.   J . A. Brown and C. D. Pomeroy, "Friction Between Coal and Metal Surfaces,"
          blecha!iical Properties of Non-Metallic B r i t t l e Materials, W. H. Walton, Ed.,
          Interscience Publishers, Inc., New York, 1958, p . 419.

    24. bl. M. Protod'Iakonov,    "To t h e Question of' a Unified Method ol Determining the
          Strength of Coal," I z v e s t i i a , A USSH o.T.M., No. 2, 1953, pp. 283-298.
                                                  N




                                                                                                 I




                                     55,
                                                                                            1
                                     50   -
                                     45   -
i
L
i
                                 -
I




                                                                             LEGEND
                                                               0   - PITTSBURGH      SEAM



                                                                     0 -HIGH SPLINT
                                                                         -
                                                                     0 C- SEAM

                                      0            5      IO        15          20          25
                                                       ASH CONTENT. %




                       ?'ionre   9.           Effect of Ash on t h e Index of Abrasion
102
     ? ? 'u? ? ? N o !
     mal al f     al P - . a l a l
             (u




     "?-?"??<?
     ooolnwall-al
     3 3 f m m m m m




     E - N rl mw N * m
      ... .. . ..
     fmmCUma3dE-
     N N N r l O d r l r l




H
H
ai
4
P
€7
    i




    I




    I




I


        -   I
                                                      106
                                                                                     i' I




                            Figure. 1. Sampling Procedure




                            160   -       A                         LEGEND
                       I

                       A
                       a                              0   - PITTSBURGH     SEAM
                       s
                       I 140
                                  -
                                  -
                                                      A   - POCAHONTAS      SEAM
                                                              EASTERN KENTUCKY
                       In                                      A-WINIFREDE
                       W
                       z          -                            0 -HIGH SPLINT
                                                               0 - C- SEAM
                       7    120   -
                       a          -
                       z          -
                       -
                       y
                       I
                            100
                            n     -
                       In
                       W
                            80    -
                       (L
                       a          -
                       T
                            60    -
                       W
                       0
                       6
                       m
                                  -
                       2    40-
                                                                                       1
                       m                                                              I


                            20        I   I   ,   '       '     I    '   I   *   l




                                                                                       ' I
Figure 2.   Relationship of Brabender Hardness and Hardgrove Grindability Index
i




                                                           LEGEND
                                                  - PITTSBURGH              SEAM
                                          A -POCAHONTAS SEAM
                                                      EASTERN KENTUCKY
                                                       A-WINIFREDE
                                                       0 -HIGH -SPLINT
                                                       0 - C- SEAM
'0



                                      0               20           40       60         80           100       120
                                                  HARDGROVE GRINDABILITY INDEX




     Figure 3.    Relationship        f
                                     g Microtumbler Strength and Hardgrove G r i n d a b i l i t y Index




                                      A


                                                           * /          /-- ' A
                                                                                            \
                                                               /
                                                                                                \A
                                                                                                     \
                                      A   /
                                                  /        *            LEGEND
                                                                                            A         /

                                                               0   - PITTSBURGH  SEAM
                                                               A -POCAHONTAS SEAM                    A A\AA
                                                                   EASTERN KENTUCKY
                                                                    A - WIN IFREDE
                                                                    0 -HIGH SPLINT
                                                                    o - C- SEAM
                                              I                I        I          I            I         I
!
'                       n
                        "        I

                         30     40        50               60           70         80       90            100       10
                                                                                                                     1
\
                                          HARDGROVE GRINDABILITY INDEX


t       Figure   4.   Relationship of Index of Abrasion a n 3 Hardgrove G r i n i a b i l i t y Index
1.
                                                    0
                                                   18




                    0
                   10




                                                            \
                                                                \
                                          LEGEND
                               - PITTSBURGH SEAM
                               - POCAHONTAS SEAM
                                EASTERN KENTUCKY
                                 A-WINIFREDE
                                 0 -HIGH SPLINT
                                                                     'F
                                     -
                                 0 C- SEAM
                                 I                 I
                                20          25     30           35       40   5
                               VOLATILE MATTER, % DAF BASIS




Figure 5.    Relationship Between Hardgrove Grindability and Coal Rank




                  W
                                                                    LEGEND

                  @
                  L
                  9
                      61
                       0k
                                 /
                                     /             A
                                                       - PITTSBURGH
                                                       - POCAHONTAS
                                                                     SEAM
                                                                      SEAM
                                                        EASTERN KENTUCKY
                                                         A - WlNlFREDE
                                                         0 -HIGH SPLINT
                                                         0-C-SEAM

                      40
                           8         IO      2
                                             1         14            6
                                                                     1    8
                                                                          1   20
                                           AVERAGE REFLECTANCE


Figure   6. delationship Between Ilardgrove Grindability Index and Rank
I



                              W
                              X




                              9 90
                                   'looi
                                     \
                                       110,




                              >.                                                   - .-_- N D
                                                                                   LEGE
                              k             -
                              _I                                        0 -PITTSBURGH     SEAM
                              rn       80-                              A   - POCAHONTAS  SEAM
                              2
                              -             -                                EASTERN KENTUCKY
                              a:                                                -
                                                                              A WlNlFREDE
                                       70-                                    0 -HIGH SPLINT
                              >
                              W             -                                 0 - C- SEAM
                              B
                              Y
                              L
                              4
                                       60-
                                            -
                                                         e'                                   0


                                             0
                                       5 0 -00           0



                                       40
                                                e,            &A
                                                                                    I
                                         0           5        IO        15          20        25        :
                                                              ASH CONTENT, %


                  Figure 7.    Effect of Ash on Hardgrove Grindability Index




                          2                                                  EASTERN KENTUCKY
                          a                                                   A -WINIFREDE
                          f   70-                                             0 - H I G H SPLINT
                          a                                                    -
                                                                              0 C- SEAM




                              30   I
                                   5
                                                 I
                                                IO       15
                                                                    I
                                                                   20         25
                                                                                         I
                                                                                         30        35
                                         TOTAL MICRINOIDS. EXINOIDS, RESINOIDS, %

    _i.Z d r ? _ .
    T              Effect of' Petrographic Composition on the Hardgrove Grindability Index
                EFFECT O IGNEOUS INTRUSIVES ON THE CHEMICAL, PHYSICAL,
                        F
                        AND OPTICAL PROPERTIES OF SOMERSET COAL
                          V. H. Johnson, R. J . Gray, and N. Schapiro
                                       U. S. s t e e l Corporation
                                      Applied Research Laboratory
                                           Monroeville, Pa.


                                                 In t r o d u c t i o n

                 m a n i n a t i o n of e x p l o r a t o r y d r i l l cores taken from a l i m i t e d a r e a n e a r
Somerset, Colorado, d i s c l o s e d some c o a l beds a s s o c i a t e d with s i l l s , o r h o r i z o n t a l
bodies, of monzonite and d i o r i t e ro c k . These s i l l s , o r igneous i n t r u s i o n s , were
formed when t h e rock, i n a molten s t a t e , invaded t h e coal-bearing s t r a t a . The
co a l s range i n rank from h i g h - v o l a t i l e bituminous through a n t h r a c i t e t o n a t u r a l
coke. The m a t e r i a l t ra n s f o rm a t i o n of c o a l t o coke produces chemical, p h y s i c a l ,
ana petrographic changes. This i n v e s t i g a t i o n w a s conducted t o determine t o what
ex t e n t v a r i a t i o n s i n t h e chemical, physical, and petrographic d a t a can be used t o
a s s e s s t h e d e l e t e r i o u s e f f e c t of t h e i n t r u s i v e s on t h e coking q u a l i t y o f t h e coal.


                                     Materials and m p e r i m e n t a l Work

              Samples of c o a l s and n a t u r a l coke were s e l e c t e d from t h r e e 6-inch c o r e s
from exploratory diamond-drill h o l e s near Somerset, Colorado. A map of t h e
Somerset a r e a of Delta County, Colorado, Figure 1, shows t h e l o c a t i o n of t h e
h o l e s from which t h e cores were obtained. The B-1 c o a l w a s sampled from h o l e s 1
and 2, t h e B-2 and C c o a l s were sampled from h o l e 3 . A t h i n c o a l between t h e B-1
and A c o a l s was sampled i n hole 1. The 35 core segments sampled were chosen t o
include similar m a t e r i a l and t o a c c e n t major changes i n t h e c o a l seams.

                   Proximate and u l t i m a t e chemical analyses and r e f l e c t a n c e , and r e s i s t i v i t y
measurements were performed f o r each sample. Since t h e s e chemical and p h y s i c a l
p r o p e r t i e s of coal change by thermal treatment, t h e s e p r o p e r t i e s a r e used as i n d i c a -
t i o n s of t h e degree o f t h e r m a l metamorphism. Ordinarily, chemical d a t a alone should
s u f f i c e t o i n d i c a t e t h e a e g r e e of thermal a l t e r a t i o n ; however, t h e c o a l samples
f r eq u e n t l y proved t o be of h i g h a s h y i e l d and not s u i t a b l e f o r r o u t i n e coal-chemical
tests.                                                                         5



                To r e l a t e t h e temperature involved i n t h e thermal a l t e r a t i o n of c o a l by
igneous i n t r u si o n s , samples of u n a l t e r e d c o a l from t h e seams w e r e thermally t r e a t e d
i n t h e l a b o r a t o r y . Ten 15-gram samples of minus 8-mesh Somerset c o a l were carbonized
i n covered c r u c i b l e s i n a n e l e c t r i c box furnace a t a h e a t i n g rate of 5.4 F p e r
minute t o predetermined temperatures ranging from 2U F t o 1832 F. A p o r t i o n of
each carbonized sample was t h e n analyzed f o r r e f l e c t a n c e , r e s i s t i v i t y , and hydrogen
co n t e n t .

                   The following a n a l y t i c a l procedures were followed i n analyzing both t h e
d r i l l - c o r e and laboratory-carbonized samples. The average r e f l e c t a n c e i n o i l was
based on 50 r e f l e c t a n c e d e t e rm i n a t i o n s p e r sample. The r e s i s t i v i t y values were
                                                                     111



         determined f o r half-gram, minus 65-mesh samples d r i e d f o r 24 hours a t 2. F arid
                                                                                            l2
                                         l
         t e s t e d a t 20,000 p s i . A l chemical d a t a were determined by stendcrd l a b o r a t o r y
         procedures.

                         Equations were developed and c o r r e l a t i o n c o e f f i c i e n t s were determined
         f o r t h e r e l a t i o n s h i p s of temperature with r e f l e c t a n c e , r e s i s t i v i t y , and hydrogen
         content of t h e coals, Table I.


                                                  Results and Discussion

                            When c o a l and/or a s s o c i a t e d rocks i n place i n t h e e a r t h are invaded by
         molten rock, t h e r e s u l t i n g a l t e r a t i o n of t h e c o a l i s similar t o t h e thermal
         a l t e r a t i o n produced i n commercial carbonization processes. For t h i s reason
         chemical and p h y s i c a l changes produced i n laboratory-carbonized c o a l s can be
         compared with similar changes i n c o a l s t h a t have been thermally a l t e r e d by igneous
         i n t r u s i o n s . I n a d d i t i o n , t h e t h i c k n e s s of t h e i n t r u s i o n and i t s d i s t a n c e from
         t h e c o a l seam have been r e l a t e d t o t h e degree of c o a l a l t e r a t i o n SO t h a t t h e damage
         s u s t a i n e d by t h e c o a l o r c o a l s can be approximated with a minimum of a n a l y t i c a l
         t e s t data.

                            I n t h e following d i s c u s s i o n t h e p h ys i c a l and chemical p r o p e r t i e s of t h e
         d r i l l - c o r e samples a r e compared with t h o s e of c o a l s carbonized i n t h e Laboratory
         at various temperatures. Following t h i s , t h e r e l a t i o n of the degree of c o a l
         a l t e r a t i o n t o t h e source of h e a t is discussed.

         P h y s i c a l and Chemical Changes i n Thermally Altered Coal

                            The o p t i c a l re fl e c t a n c e , e l e c t r i c a l r e s i s t i v i t y , and hydrogen content
         were determined f o r Somerset h i g h - v o l a t i l e c o a l carbonized a t d i f f e r e n t temperatures
         i n t h e l a b o r a t o r y . The r e f l e c t a n c e i n c re a s e s and t h e r e s i s t i v i t y and t h e hydrogen
         content decrease as the carbonization temperature i n c r e a s e s , a s shown i n Figure 2.
         The Somerset h i g h - v o l a t i l e rank coal, which has not been a l t e r e d thermally, has a
         r e f l e c t a n c e of about 0.7 p e rc e n t , a r e s i s t i v i t y of about 4.2 x 10l1 ohm-cm, and a
         hydrogen content of about 5.9 p e rc e n t . When c o a l has been a l t e r e d t o a r e f l e c t a n c e
         g r e a t e r t h a n 2.0 percent, a r e s i s t i v i t y of 6.5 x lo7 o r more, and a hydrogen c o n t e n t
         o f l e s s t h a n 4.0 percent, it can be considered a s non-coking. I n t h e l a b o r a t o r y
         samples t h e v a r i a t i o n s i n t h e re fl e c t a n c e , r e s i s t i v i t y p r o p e r t i e s , and hydrogen
         content have been r e l a t e d t o t h e temperature of carbonization because temperature
         was t h e v a r i a b l e i n the sample p re p a r a t i o n . The c o r r e l a t i o n c o e f f i c i e n t s f o r t h e
         r e l a t i o n of temperature t o both r e f l e c t a n c e and hydrogen is F? = 0.99 and f o r t h e
         temperature-to-hydrogen r e l a t i o n is R2 = 0.96. The r e f l e c t a n c e , r e s i s t i v i t y ,
         and hydrogen measurements on t h e d r i l l specimens from t h e cores were used t o
         estimate t h e temperature t o which t h e c o a l had previously been heated, Figure 3.
     I   Equations expressing t h e r e l a t i o n s h i p s of temperature with r e f l e c t a n c e , r e s i s t i v i t y ,
         and hydrogen content, TaMe I, developed f o r c o a l carbonized i n t h e l a b o r a t o r y were
         used i n c a l c u l a t i n g temperature involved i n t h e thermal a l t e r i n g of t h e c o a l and coke
         i n t h e core samples. The c o r e samples range from v i r t u a l l y u n a l t e r e d c o a l t o coke
         t h a t has been t h e rm a l l y a l t e r e d a t a maximum temperature o f not l e s s t h a n 156 F o r
'I
         more t h a n 2200 F. I n d i r e c t l y determined tempe a t u r e s i n and near intrusionsly*
         and d i r e c t l y determined temperatures f o r lava2y a r e within t h i s range. It appears
         t h a t c o a l may be used as a maximal geothermometer. However, t h e temperatures
         c a l c u l a t e d from r e f l e c t a n c e a r e h i g h e r t h a n t ho s e c a l c u l a t e d from r e s i s t i v i t y and
         t h e s e i n t u r n a r e h i g h e r t h a n t h o s e c a l c u l a t e d from t h e hydrogen c o n t e n t , Figure 3.


i
         *   See references.
                                                                                                                                   /




                                                            112


P a r t of t h i s discrepancy i s due t o the l a r g e percentage of ash-forming materials,
which a f f e c t t h e r e s i s t i v i t y and hydrogen measurements. Reflectance i g considered
as t h e most a c c u r a t e i n d i c a t o r of rank changes r e s u l t i n g from thermal a l t e r a t i o n
s in ce it i s not a f f e c t e d by ash-forming minerals i n t h e samples. However, when
co als o f d i f f e r e n t rank a r e carbonized under t h e same conditions, t h e highest-rank
c o a l w i l l produce coke with t h e h i g h e s t r e f l e c t a n c e . I n t h i s study, t h e c o a l
carbonized i n t h e l a b o r a t o r y i s t h e same rank as t h e u n a l t e r e d c o a l recovered i n
t h e d r i l l core.

                 The v i s i b l e changes t h a t occur i n t h e transformation of c o a l t o coke a r e
shown i n Figure 4. The r e f l e c t a n c e , r e s i s t i v i t y , and hydrogen data are a l s o shown
t o a s s o c i a t e t h e s e changes w i t h t h e v i s i b l e changes i n t h e c o a l and coke s t r u c t u r e .
The photomicrographs shown i n Figure 5 i l l u s t r a t e a l t e r e d and u n a l t e r e d c o a l i n a
s i n g l e sample of c oa l , p y r o l y t i c carbon (carbon from cracked hydrocarbon gases) and
min e r a l matter i n t r u d e d i n t o t h e c o a l .

Relation of t h e Thermal A l t e r a t i o n of Coal
To t h e P o s i t i o n and Thickness of t h e I n t r u s i v e

                    The changes i n r e f l e c t a n c e , hydrogen and v o l a t i l e - m a t t e r content with
d i s t a n c e from t h e i n t r u s i o n s i n t h e samples taken from d i f f e r e n t depths i n t h e f o u r
d r i l l h o l e s a r e shown i n Figures 6, 7, 8, and 9. I n hole 1, B-1 seam (Figure 6 )
i s in t r u d e d near t h e t o p by two s i l l s of n e a rl y equal t h i c k n e s s f o r a t o t a l of 1 . 5
f e e t . The h e a t from t h e s i l l s was s u f f i c i e n t t o b r i n g 8.0 f e e t o f t h e 14-foot seam                i
t o a r e f l e c t a n c e of 2 p e r c e n t o r more. I n t h e middle of t h e c o a l column t h e
r e f l e c t a n c e drops a b r u p t l y ( i n only 0.8 f o o t ) from more t h a n 5 t o l e s s t h a n 2 percent.
The base of t h e seam, c o n s i s t i n g of about 6.0 f e e t of coal, w a s only s l i g h t l y
a l t e r e d by metamorphism and can be considered as coking c o a l .

                 I n h o l e 3 , B-2 seam (Figure 7) i s i n contact near t h e t o p with an 8.5-
f o o t s i l l o v e r l a i d by 2.8 f e e t of s h a l e and 3.7 f e e t of coke, which i s i n t u r n
o v e r l a i d by 1 1 . 2 f e e t o f i n t r u s i v e rock. I n t h i s c o a l column, the e n t i r e 7.8
f e e t of c o a l has coked completely. The r e f l e c t a n c e decreases as t h e d i s t a n c e
from t h e s i l l i n c r e a s e s .

                  I n h o l e 3 , C-seam (Figure 8 ) i s thermally metamorphosed i n t h e bottom
t h i r d of a n 11.6-foot c o a l column. Comparison of t h e sample i n t e r v a l s with t h e
d r i l l e r ' s l o g shows t h a t 1 . 2 f e e t i s unaccounted f o r a t t h e base of t h e column.
It was assumed t h a t t h e i n t r u s i v e occurs i n t h i s p o s i t i o n . Approximately 3.6
feet of t h e b a s a l p o r t i o n of t h e column exceeds 2 percent r e f l e c t a n c e . The
remaining 8.0 f e e t of coal i s only s l i g h t l y a l t e r e d and should be considered
coking c o a l . The r e f l e c t a n c e drops from 5 t o l e s s t h a n 2 percent i n an i n t e r v a l
of about 2.0 f e e t . Thus t h e change from coke t o c o a l i s abrupt.

               I n h o l e 2, B - 1 seam (Figure 9 ) i s not i n d i r e c t c o n t a c t with a n i n t r u s i o n
b u t i s s e p a r a t e d from a n overlaying s i l l by 38.6 f e e t of s h a l e . The i n t r u s i o n
t o t a l s 26.9 f e e t ; however, a 7.5-foot u n i t of n a t u r a l coke s p l i t s t h e s i l l s and
o n ly 15.9 f e e t of s i l l was considered e f f e c t i v e i n t h e thermal metamorphism of t h e
c o a l . The e n t i r e 11.4-foot column has been a l t e r e d t o a n t h r a c i t e and is non-coking.
There a r e v i r t u a l l y no v e s i c l e s developed i n t h i s coal. This c o a l has probably
been s u b j e c t e d t o l e s s r a p i d h e a t i n g o r g r e a t e r p r e s s u r e s t h a n t h e c o a l s i n which
t h e coke s t r u c t u r e developed.
                                                                                                                                          /
                                                                     113


                           The graphic p r e s e n t a t i o n s show t h a t i n t e r n e changes i n a c o a l by contact
         with i n t r u s i o n s extend. only a s h o r t d i s t a n c e from t h e c o n t a c t . However, t h e amount
         of c o a l a l t e r a t i o n , while undoubtedly r e l a t e d t o t h e temperature of t h e i n t r u s i o n ,
         is a l s o r e t e d t o t h e t h i c k n e s s of t h e i n t r u s i o n and i t s d i s t a n c e f r o m t h e coal.
                        l-7
         Blignault,3 i n h i s i n v e s t i g a t i o n of t h e d o l e r i t e i n t r u s i o n s i n t h e Natal C m i e l d s ,
         found t h a t as t h e r a t i o of t h e d i s t a n c e (D) from t h e c o a l t o t h e t h i c k n e s s of t h e
         i n t r u s i v e (T) decreases, t h e v o l a t i l e matter (daf)* of t h e c o a l decreases from t h e
         u n alte r e d c o a l . For t h e s e r e l a t i o n s h i p s t o hold t r u e , t h e i n t r u s i v e temperature
         must have been nearly constant. Data from t h e pr e s e n t i n v e s t i g a t i o n were used t o
         test t h e a p p l i c a b i l i t y of Blignault's f i n d i n g s , but r e f l e c t a n c e was used as t h e
         rank parameter i n preference t o v o l a t i l e matter.

                           The r e l a t i o n of D/T t o t h e r e f l e c t a n c e is shown i n Figure 10. Distance
         is taken from contact of t h e i n t r u s i o n t o t h e c e n t e r of t h e i n d i v i d u a l c o a l u n i t s .
         The following sill thicknesses were used i n t h e c a l c u l a t i o n : 1.5 f e e t f o r € -                     31
         seam i n h o l e 1 8.5 f e e t for E-2 seam, and 1.2 f e e t for C seam i n h o l e 3, and
                                    ,
         15.9 f e e t for B-1 seam i n hole 2. The d a t a shown i n Figure 10 i n d i c a t e t h a t t h e
         r a t i o of t h e d i st a n c e of t h e i n t r u s i v e from t h e c o a l t o t h e t h i c k n e s s of t h e
         i n t r u s i o n i n c r e a se s as r e f l e c t a n c e decreases.

                          Coal a l t e r a t i o n i n coal-bearing s t r a t a a s s o c i a t e d with i n t r u s i o n s should
         be u s e f u l i n e s t a b l i s h i n g d i s t a n c e from i n t r u s i v e c e n t e r s and t h e d i r e c t i o n of
         t h e leading edge of an i n t r u s i v e body a s w e l l as i n e s t a b l i s h i n g t h e d e l e t e r i o u s
         e f f e c t s s u s t a i n e d by t h e i n d i v i d u a l c o a l s i n . a c o a l f i e l d .


                                                              u mr
                                                             s m ay
                            Examination of coal-bearing s t r a t a obtained from d r i l l - c o r e samples taken
         from t h e Somerset a r e a i n d i c a t e d t h a t p o rt i o n s of t h e c o a l have been thermally a l t e r e d
         a s a r e s u l t of exposure a t some time t o molten rock (igneous i n t r u s i o n ) . The degree
         of a l t e r a t i o n of t h e c o a l was such t h a t t h e coking p r o p e r t i e s of t h e c o a l have been
         a f f e c t e d . I n t h e i n v e s t i g a t i o n , it was found t h a t measurements of r e f l e c t a n c e ,
         e l e c t r i c a l r e s i s t i v i t y , and hydrogen content could be used t o determine t h e degree
                                                                                                                        a
         of a l t e r a t i o n of t h e c o a l . The d a t a i n d i c a t e t h e a l t e r a t i o n of t h e coal w s r e l a t e d
         t o th i c k n e s s and d i s t a n c e of t h e i n t r u s i v e from t h e c o a l bed. I n a d d i t i o n it YBB
         found t h a t , within limits, c o a l may be used as a maximal geothermometer.


                                                          References

     I   1. T. S. Lovering, "Temperatures I n and Near I n t r u a i o n s , " Economic Geology,
            F i f t i e t h Anniversary Volume, pp. 249-281, 1955.
.i       2.    E. Ingerson, "Methods and Problems of Geologic Thermometry," Economlc Geology,
               F i f t i e t h Anniversary Voluhe, pp. 341-410, 1955.

 I
         3. J. J. G. Elignadt,               "Field Relationships of t h e B l e r i t e I n t r u s i o n s i n t h e Natal
',             C o a l f i e l d s, " Transactions of t h e Geological Society of South A f r i c a , Volume 55,
I
               PP. 19-31, 1952.
i
F'
         * dry,    ash f r e e .
                                                                                                  /




                                                114




                                              'Pable I


                   Equations Used t o Express t h e Relationships
                  of Temperature with Reflectance, R e s i s t i v i t y ,
                            and Hydrogen Content


1.   Temperature, F =       222.6514 + 6 1 l 2 8Ro
                                        4..6                   -      147.9204 b2+ 1 . l 2 ~+,3
                                                                                    26.4
           Ro = maximum r e f l e c t a n c e i n o i l

2. Temperature, F       =   1497.4304 - '75.9517 - 5.9162 $ - 0.5102 R3
                                                R
           R = e l e c t r i c a l r e s i s t i v i t y i n ohm-cm

3. Temperature,      F =    2279.10l2 - 749.llglH + 178.4985 H2                  -   17.0855 H3
           H =hydrogen c o n t e n t , weight percent ( d a f )




                                                                                                      I
t                                               0 OlAMONDORlLL MOLE LOCATIONS

                                                /OUTLINE          OF LEASE L R E I




                                                           SCALE IN F E E T


       PAONI
               SOUERSET




    Figure 1. Location of Diamond-Drill Holes in Somerset Area, Colorado
                                    116
                                                                                                           I




                                                                                              2

                                                                                          II


                                                                                          IO

                                                                                          3

                                                                                          3

                                                                                          7 5
                                                                                                  E
                                                                                                  r
                                                                                          6 O
                                                                                            >
                                                                                                  -
                                                                                                  I
                                                                                          5 2
                                                                                                  I-
                                                                                                  v)
                                                                                          4 ,
                                                                                                  w
                                                                                                  U
                                                                                          3            0
                                                                                                  (3
                                                                                                  0
                                                                                                  -I
                                                                                          2

                                                                                          I

                                                                                          0

                                                                                          -I


                                                                                          -2


                                                                                          68
                              TEMPERATURE, F

Figure 2.   R e l a t i o n of Temperature t o Reflectance, R e s i s t i v i t y , and
            Hydrogen f o r Coal Carbonized i n t h e Laboratory
     7




     6



'i
     c
     v



t




I




I


                                                                                                     Q

                                                                                                     -I


                                                                                                     -2

                                                                                                     -3

                                         TEMPERATURE,          F
I


         Figure   3.   Relation of Calculated Temperature t o Reflectance, R e s i s t i v i t y ,
                       and Hydrogen for D r i l l Core Samples of C d




                                                                                                          I
                                             118


                                 .ectance,     Resistivity,      Hydrogen,
                                 zrcent          ohm cm          w t percent      Description




                                  0-7          3.0    x   10”       6.2        Coal i s unaltered




                                                                               Coal i n c r e a s e s i n
                                  0.9          8.4 x      lolo      5.5        r e f l e c t a n c e but
                                                                               vacuole development
                                                                               has n o t occurred.




                                  30
                                   .           2 1 x 10‘
                                                .                   3.6        Small pinpoint
                                                                               vacuoles develop.




                                  4.5          20
                                                .         104        .
                                                                    28         Vacuoles i n c r e a s e
                                                                               i n size.




                                                                               Vacuoles continue
                                   5.6             1.3 x io          2 -5      t o increase i n
                                                                               size.




                                   7.5             2.9 x us2         1-3       &isotropic          coke
                                                                               s t r u c t u r e develops.




Figure 4.   As t h e ’Phermal Metamorphism of Coal Increases, t h e merit of
            Vacuole Development In c re a s e s and t h e Reflectance Increases,
            While R e s i s t i v i t y and Hydrogen Decrease. Reflected l i g h t ,
            X3W.
                                                      Particles of c o a l shoving vide
                                                      variation i n reflectance i n a
                                                      single sample representing a
                                                      1.7-foot c o a l interval. This is
                                                      evidence of abrupt changes in the
                                                      degree of thermal metamorphism.



    I




                                                      Coke (pyrolytic carbon) produced
                                                      from cracking of hydrocarborn or
                                                      incomplete combustion of gas.




4                                                     Mineral matter derived from the
                                                      diorite intruded i n t o the coal.




        Figure 5 .   Photomicrographs Show Thermally Metamorphoeed Coal, Pyrolytic
                     Carban, and Intruded Mineral Matter. Reflected U a t , B O O .
                                               120




     I
14

          COKE

         IGNEOUS
           SILL
12        COKE
         GNEOUS
          SILL
          COKE


          COKE




              -,




              -
              a
              C
              c




                                               IO         20         ' 30                 40
                                           VOLATILE MATTER, weight percent (daf 1
                                                                                           i
                                  0    1     2       3         4         5   6      7      8
                              REFLECTANCE, percent in oil   - HYDROGEN. weight     percent (daf 1

           Figure   6.   P r o f i l e of Coal and S i U with Reflectance, Hydrogen, and
                         V o l a t i l e Matter f o r Indicated Coal U n i t s , B-1 Seam, Hole G-15.
                                                   121




     I




     I




     I(


          IGNEOUS
             SILL
             e 511
c
0 '
c          COKE

v)
             i
v)
W
2
Y
O(
I
I-           2
I           0
            -
            l
4           a
W           L
v)          W
            c
            2
     4      a
            0
            w
            v)
            a
            w
            a
            V
            z
     i


           COAL
             OR
     C     COKE


                                   0           IO        20            30                   40
                                           VOLATILE MATTER, weight percent (daf 1
                                   b                                                        ,
                                  0    1     2      3     4     5    6      7      0
                              REFLECTANCE, Dercent inoil - HYDROGEN, weight percent (dot)


           Figure 7.   P r o f i l e of Coal and S i l l s with Reflectance, Eydrogen, and
                       V o l a t i l e Matter f o r I n d i c a t e d Coal Units, B-2 Seam, Hole G-16.
                                            322




     14




     12

                                                                                      1
     IO

                                                                                    i     MATTER


v)
v)
w
                                            REFLECTANCE             @-
                                                                    ,
                                                                     I
Y
2 6
I
b-
I
a
W                                                                                                      -L
v)

     4                                                                                                 0
                                                                                                       z
                                                                                                       Y
          w                                                                                            0
          Y                                                                                            V
          0                                                                                            z
          V                                                                                            0
                                                                                                       z
     2
              I

                                                                                                            I


     0

                                      VOLATILE MATTER, weight percent ( d o f )
                               r
                               0  I     2       3          4    5     6     7     8
                         REFLECTANCE, percent inoil    -   HYDROGEN, weigh percent (daf)


          Figure 8 .   P r o f i l e of Coal and S i l l s with Reflectance, Hydrogen, ‘and
                       V o l a t i l e Matter f o r I n d i c a t e d Coal Units, C Seam, Hole G-16.
  SHALE
  38.611




                                                                       ANCE




                                                     \
                          1      I      I      I     1      I      1

                          0           .IO       20            30               40
                                  VOLATILE MATTER, weight percent (dof)
                         r                                                      1
                         0    1     2       3        4      5      6      7      8
                     REFLECTANCE, percent in oil   - HYDROGEN, weight    percent (daf)

Figure   9.   P r o f i l e of Coal and S i l l s with Reflectance, Hydrogen, and
              V o l a t i l e Matter for Indicated Coal U n i t s , B-1 Seam, Hole G-17.
                                                   124




                                                                                    HOLE No. COAL SEAM
     9.c                                                                        A    G-15          BI
                                                                                0    6-16          82
                                                                                     G-16          C
                                                                                X    G-17          BI
     8.
      0



     7.C


-
.-
.- 6.0
C                           i
*           0
C
t               0            '\
     5.c                          \A
                                  \
W
V
z
 -
                                   \x
2 4.0
V
W
-I
L
I
W
= 3.c

     2 .c



     I .c



                                                                           I
       C
                    I .o   I 0          3.0        4         5.0          6.0        7.0
                                              COAL-' ? S I L L DISTANCE
                                                  SI L THICKNESS

            Figure 10. Reflectance Versus Ratio of Coal-to-Sill Distance to                 sill
                       Thickaess for Wermally Altered Somerset Coal
                                                     125 I
                                     TEE EFFECT OF MA&      COMPOSITION ON THE
                                        BINIERLElSS BRIQKETI'ING OF HOT C A
                                                                         HR

                                                             M. F. TROODS
                                                                 .
                                                             G. N RABBERJAH
                                                             K. ELSIAORTH
                                                              .
                                                             s BENNETT
                                                 NATIONAL COAL BOARD
                                             COAL RJEEARCH ESTABLISEUENT
                                             STOKE ORCHARD     CIIELTENHAN
                                                                  ENGLAND




1.     INTRODUCTION

     The process of hot char b r i q u e t t i n g now being developed a n d e x p l o i t e d by the
National Coal Board c o n s i s t s of the d i r e c t b r i q u e t t i n g of hot fluid-bed carbonised
char. The p r i n c i p a l process v a r i a b l e s have already been discussed by Habberjam and
Gregory (I), this paper concerns an e x t e n s i o n o f t h e i r work.
              and

        The c o a l seams so f a r considered f o r t h e hot c h a r b r i q u e t t i n g o f l o w rank c o a l
have been of similar petrographic composition, i c e . about 6& v i t r i n i t e , 17% e x i n i t e ,
and t h e remainder composed of m i c r i n i t e 1 and 2, f u s i n i t e , s h a l e and p y r i t e . There
i no reason why o t h e r c o a l seam6 should not be examined, p a r t i c u l a r l y s i n c e c e r t a i n
  s
c o a l preparative treatments, e.g. s e l e c t i v e f r o t h f l o t a t i o n and dense medium separa-
tions,have the e f f e c t of concentrating one p a r t i c u l a r maceral or group o f macerals a t
t h e expense of the others. It w a s considered that c o a l s of unusual maceral composition
might e x h i b i t a new range of b r i q u e t t i n g p r o p e r t i e s .

      Although work has been published on the thermal changes o c c u r r i n g i n i n d i v i d u a l
c o d macerals, no systematic survey has been made u s i n g B r i t i s h low rank c o a l s heated
i n fluid-bed conditions.

         Many workers, notably Kr8ger (2) and F i t z g e r a l d (3) have shown t h e p y r o l y s i s
behaviour of the i n d i v i d u a l c o a l macerals t o be d i f f e r e n t . They, as w e l l as
Permitina (4) and Amnosov (5), were working under coke oven c o n d i t i o n s ; Permitina,
using polished microscope s e c t i o n s of Russian coking c o a l c h a r s , showed that only
v i t r a i n , and v i t r a i n i s e d masses and s p o r e s , c o n t r i b u t e d s i g n i f i c a n t l y t o caking
behaviour. Permitina a l s o showed that f u s a i n i s e d micro-components, xylene* and
m i n e r a l s , made no c o n t r i b u t i o n , w h i l s t x y l o - v i t r a i n and p a r t i a l l y f u s a i n i s e d a t t r i t i o n
p z r t i c l e s had low czking p r o p e r t i e s . Ergun ( 6 ) , working w i t h a microscope hot-stage,
h a s confirmed t h a t v i t r i n i t e s and e x i n i t e s undergo v i s i b l e changes d u r i n g carbonisa-
t i o n , and t h a t the o t h e r c o n s t i t u e n t s remain comparatively i n e r t . Taylor (7) s t u d i e d
the thermal p r o p e r t i e s o f t h e S t o p s c o n c e n t r a t e s d u r i n g c a r b o n i s a t i o n , and lists a
considerable quantity of r e l e v a n t l i t e r a t u r e .

     In t h i s work the maceral system of c o a l component c l a s s i f i c a t i o n w i l l be used.
The components analysed w i l l be:

                         vitrinite       , exinite,        total inertinite            , shale       and p y r i t e .

The i n e r t i n i t e will be f u r t h e r divided into micrinite I micrinite 2, and fusinite.
                                                                      ,




*      The word "xylene" i s taken d i r e c t l y from a t r a n s l a t i o n of P e r m i t i n a ' s
       paper. It probably i m p l i e s xylo-fusain.
                                                          126

       The d e t a i l e d o b j e c t s of t h e present study were:

       (a)      t o devise a method f o r e s t i m a t i n g volume chsriges i n the r a c e r e l s
                of l o w rank c o a l c h a r s heated i n a f l u i d bed;

       (h)      t o show whether v a r i a t i o n s i n the maceral compositions of the c o a l
                feed would a f f e c t the c k a r b r i q u e t t i n g process;

       (c)      t o follow m y changes occurring i n t h e macerals of chzrs i n the
                range 380' t o 5OO0C.

2.     rnL%(IMENTAL

2.1.   Coal sample p r e p a r a t i o n

     Samples of f o u r low rank, high v o l a t i l e c o a l s were used.                        n
                                                                                                  A a n a l y s i s of these
coals is given i n Table 1.

                                                       TABU 1

                                            Analyses of c o a l s used


        I

        -
                                                                                       Ash            !   Volatile
        I
        I Colliery
        I
                                Seam          :    grade                               % as           '    matter
        j                                         I received received                                      d.a.f.
                                                  I
        j    Calverton        Eigh Main           Washed
                                                  smalls
                                                                II      7.59          11.68                 % .83

             Denby H a l l      Mixed
                                                   smalls
                                                   Washed
                                                                I
                                                                I
                                                                        5025         16.50            ,     37.80


             Birch
               Coppice
                                Mixed              Washed
                                                   smalls
                                                                 1!     5.53          11.11                 41.19    '



                                                                 I
             Dexter             Mixed              Washed               6.18           1.66                 38.03
                                                                 1
                                                   special
                                                   beans            ,
                                                                    I




          Samples of one c o a l , namely Calverton CRC.902, were used to prepare maceral con-
c e n t r a t e s . Bards, b r i g h t s and f u s i n i s e d m a t e r i a l s were manually s e l e c t e d , and f u r t h e r
r e f i n e d by f l o t a t i o n and crushing,followed by s e l e c t i o n under a low-power lens. Three
b a s i c samples were prepared i n t h i s way, the proximate analyses being given i n
Table 2.

                                                         TABLE 2

                                     Proximate analyses of b a s i c samples


                                                                           I
                                                            Durain         1   Vitrain        '    ~usain
                                                                           I
                      Moisture                               5.95%              12.47%               4.55%
                      Ash (dry b a s i s )                   7.67%               1.0796             10.29%
                      V o l a t i l e matter (c.a.f)        38.49%              35.61%              24.80%
                                                             127
             Ten mixes were prepared from the t h r e e b a s i c samples, t h e vitrain, d u r e and
        fusein samples being l i s t e d as Sample Nos. 1, 8 and 10 r e s p e c t i v e l y (Table 3).

                                                           TABLE 3

                                            Analyses of Calverton c o a l
                                            macerdl concentrate blends

                                                      -                                                             -
               Sample No.                    1      2
                                                    --3
                                                                                                                    - 10


k          Vitrinite            Vole $ 97.9         '4.7     51.4                          35-7 14.5          16.7 23.9
           ExiDite                          1.7      9.
                                                      8      28.6                          14.8 51.1          3k4.4 5.4
t          Total
                inertinite                  0.4     5.5      19.3                          49*3 344.4 48.5          70.3
           Micrinite 1                      0.3     7.5      12.7                          27.2 26.8 31.0           33.7
           Micrinite 2                      0.1     4.8       6.5                          15.2  7.3 12.1           24.3
           Fusinite
           Shale
           Pyrite
                                    11

                                    11

                                    11
                                                    3.2       0.1
                                                              0.7
                                                                                            6,9
                                                                                            0.2
                                                                                                 0.3


                                                                                                  iI
                                                                                                       5.4
                                                                                                       0.41
                                                                                                          :
                                                                                                                    12.3
                                                                                                                      0.1
                                                                                                                        0.3
                                                             -                                                      -
        2e2e Apparatus

                Two systems of fluid-bed c a r b o n i s a t i o n were used:

                   A
                (I) 2-inch laboratory-scale fluid-bed of t h e d e s i g n d e s c r i b e d by
                                                        T
                   Habberjam and Gregory (I). U apparatus was used for t h e study of
                   t h e p y r o l y s i s of macerals. Two c a r b o n i s a t i o n p e r i o d s were used in
                   this f l u i d bed, i.e. 8 and 30 min., the f i r s t 4 min. of e a c h p e r i o d
                   being t h e h e a t i n g time. Nitrogen w a s used as t h e f l u i d i s i n g gas.
\               (2)   A miniature fluid-bed and b r i q u e t t i n g mould. This a p p a r a t u s c o n s i s t e d
                      of a 0.5-inch diameter tapered mould and hardened s t e e l plunger mounted
                      i n t h e j a w s o f a hydraulic jack. A t i g h t l y f i t t i n g funnel wa6 placed
                      i n t h e t o p of t h e mould, 80 t h a t the mould and f u n n e l t o g e t h e r a c t e d
                      as a fluid-bed, t h e funnel being removed from the mould f o r b r i q u e t t e
                      production. Air and nitrogen were used 86 t h e f l u i d i s i n g gases.

             One c a r b o n i s a t i o n period wa.s used in the miniature bed, i.e.          5 min. , i n c l u d i n g
        a 2 min. h e a t i n g period.

        2.3.     T e s t i n g and analysis of samples

            The b r i q u e t t e s prepared a t 6 tons/sq.in. were t e s t e d f o r t h e i r b u l k d e n s i t y and
        mechanical s t r e n g t h by the method described by Habberjam and Gregorg (I).

               The samples f o r maceral a n a l y s i s were ground as c o a l to -10 BSS ... and reduced
        t o 30 gm. using an Otto M i c r o s p l i t t e r (8). These samples were t h e n carbonised i n
a       t h e 2-inch fluid-bed, t h e c h a r s being f u r t h e r reduced to approximately 1 gm. samples
I       before impregnation and mounting in blocks with c o l d - s e t t i n g p o l y e s t e r resin. A
I
I
    .
        flat s u r f a c e w a s ground on t h e blocks, using s e v e r a l grades of carborundum powder
        on g l a s s p l a t e s , and a high p o l i s h was obtained with f i n e alumina powder on a B o l t i n g
        allk lap.
                                                            128

      A s t a t i s t i c a l method o f a n a l y s i s , based on a technique f i r s t described by
Delesse (9) w a s used t o determine the r e l a t i v e volume of macerals i n t h e c o a l s and
chars. T h i s w a s based on t h e f a c t that, i n a c r o s s - s e c t i o n of rock, the r a t i o cf t h e
area occupied by one mineral t o t h e t o t a l c r o s s - s e c t i o n a l a r e a i s a r e l i a b l e estimate
of t h e t o t a l volume percentage of t h a t mineral.

        S e v e r a l methods of measuring t h e r e l a t i v e a r e a s of minerals i n c r o s s - s e c t i o n
have been proposed, but the most r e l i a b l e w a s taken as t h e ' p o i n t c o u n t e r ' technique
described by Qlagolev (IO).                  I n t h e o r y , the cross-section i s covered with a g r i d and
the mineral occurring under each i n t e r s e c t i o n is recorded. The r a t i o of the number
o f p o i n t s at which t h e p a r t i c u l a r mineral occurs t o t h e t o t a l number o f p o i n t s of
the g r i d may be r e l i a b l y t a k e n as t h e r a t i o o f t h e a r e a of t h e mineral t o t h e t o t a l
measured area. A mathematical proof o f these statements i s given by Chayes (11).
In p r a c t i c e , i n s t e a d of moving from p o i n t t o p o i n t on a g r i d , the polished c o a l
s e c t i o n is moved i n s u c c e s s i v e s t e p s along a number of t r a v e r s e s , and the mineral
under the crosswires is recorded at each s t e p . I n o r d e r t o limit the e r r o r to f %
                                                                                                                                         i
at 7% and t o 2 1% at             s,   a t o t a l of 1,000 p o i n t s is analysed on each sample.

          In o r d e r to e s t i m a t e t h e changes i n the volumes
t h e o r i g i n a l c o a l , i t i s necessary t o have some body
i n e r t during carbonisation.                Since t h e i r volume does
                                                                                  of t h e macerals w i t h r e s p e c t t o
                                                                                  or bodies p r e s e n t which remain
                                                                                  n o t change, comparison i s
                                                                                                                                         i
p o s s i b l e with the changing maceral volumes. Where a                        natural i n e r t m a t e r i a i s
p r e s e n t i n reasonable percentages, t h i s may be used.                     More than I($ be p r e s e n t ,
                                                                                                     must
however, t o ensure t h a t the e r r o r s a r e l e s s than the                probable e r r o r i n t h e maceral
analysis.

          For the coals Calverton, Denby H a l l and Birch Coppice, m i c r i n i t e 2, f u s i n i t e and
minerals were regarded as s t a n d a r d i n e r t s . In t h e case o f Dexter, a percentage of gas
coke ground t o -10 B.S.8. w a s added t o t h e o r i g i n a l c o a l charge. The p o r o s i t i e s , a l s o
found by a ' p o i n t counter' method, a r e a derived f i g u r e (see s e c t i o n 3 , Discussion).
S e c t i o n s o f b r i q u e t t e s were a l s o mounted i n r e s i n , and photomicrographs of sample chars
were made w i t h a Vickers p r o j e c t i o n microscope.               (See photos. 1 through 1 2 . )

3e R E m T S AND DISCUSSION
          The experimental c o n d i t i o n s f o r b r i q u e t t i n g and f o r ffiaceral a a l y s i s were un-
avoidably d i f f e r e n t . The b r i q u e t t i n g trials using t h e v e r y s m a l l q u a r i t i t i e s of sample
                                                                                                                                         I
a v a i l a b l e were c a r r i g d out u s i n g a miniature f l u i d bed which allowed f o r heating r a t e s
o f approximately 200 C/min.                 Three minutes a f t e r the attainment of c a r b o n i s a t i o n
temperature, i . e . 5 min. a f t e r sample i n t r o d u c t i o n , the b r i q u e t t e s were formed. In
t h e maceral a n a l y s i s l a r g e r samples were a v a i l a b l e , and a more convenient and conven-
t i o n a l f l u i d bed w a s employed. The rate of h e a t i n g i n this bed w a s approximately
100°C/min. and samples were analysed 4 min. and 26 min. a f t e r they had a t t a i n e d                                               I
c a r b o n i s a t i o n temperature, i.e. t o t a l residence times o f 8 and 30 min. r e s p e c t i v e l y .
Previous work had shown t h a t b r i q u e t t e s formed i n the miniature f l u i d bed a f t e r
h e a t i n g f o r 5 m i n . had a s i m i l a r performance t o those a f t e r 8             -
                                                                                              10 min. i n the more
conventional bed.

          The r e s u l t s of t h e b r i q u e t t i n g of maceral c o n c e n t r a t e s a r e given i n Figures 1 t o
3.      Calverton coal (C.R.C. 902, V.M. 37% d.a.f.1 w a s used and t h e t h r e e methods of
                                              ,
b r i q u e t t e assessment employed i,e. s h a t t e r i n d e x , a b r a s i o n index and bulk d e n s i t y ,
gave similar r e s u l t s . Maceral c o n c e n t r a t e s r i c h i n i n e r t i n i t e produced poor
b r i q u e t t e s , w h i l s t b o t h e x i n i t e and v i t r i n i t e r i c h mixtures produced good b r i q u e t t e s .
M n i t e r i c h mixtures c o n t a i n i n g over 25% micrinite 1 produced good b r i q u e t t e s ,
whereas i n e r t i n i t e r i c h m i x t u r e s d t h the same concentration of m i c r i n i t e 1 produced
poor b r i q u e t t e s . I t w a s t h e r e f o r e u n l i k e l y t h a t m i c r i n i t e 1 c o n t r i b u t e d t o t h e
production o f s t r o n g b r i q u e t t e s .          An i n t e r a c t i o n between e x i n i t e and m i c r i n i t e w a s
p o s s i b l e and this w a s n o t r u l e d o u t by t h e microscopic study of t h e macerals (Fig. 4 .                          )
                                                                                         0'
M i c r i n i t e 1 underwent some swelling between 375' and 40 C, t h e s w e l l i n g being
greater a f t e r 30 min. c a r b o n i s a t i o n than a f t e r 8 m i n . This s w e l l i n g occurred f o r all


                                                                                                                                         I
the c o a l s considered (Figs. 5 and 7 ) .

          Samples containing p r a c t i c a l l y pure v i t r i n i t e (ne% volume) produced s t r o n g
                                                                                          by
compacts throughout the range of temperatures at t h e s h o r t c a r b o n i s a t i o n time
s t u d i e d , the s h a t t e r and abrasion s t r e n g t h s f a l l i n g s l i g h t l y at the higher tempera-
t u r e s . A photomicrograph of a 97.C$1tpure"vitrinite b r i q u e t t e (Photo. 11) i l l u s t r a t e s
t h e way i n which t h e vitrinite g r a i n s appear t o jig-saw' i n t o one another. The
maceral analyses show a s e r i e s of expansions and c o n t r a c t i o n s throughout t h e range
which a r e only q u a l i t a t i v e l y followed by the o t h e r coals s t u d i e d .

          The e x i n i t e r i c h mixtures (up t o 51% volume) d i d not produce s t r o n g b r i q u e t t e s
before 410°C, but above this temperature the e x i n i t e played a n important r o l e i n
b r i q u e t t i n g , e i t h e r alone or i n combination with v i t r i r d t e o r m i c r i n i t e 1. The
q u z l i t y of e x i n i t e r i c b compacts r o s e t o a maximum a t about               C and t h e n f e l l
grzdually. A photomicrograph (Photo.12) of a 'whole' c o a l b r i q u e t t e ( e f i n i t e I%,
vitrinite 665. rnicrinite 1 9 , and m i c r i n i t e 2 p l u s f u s i n i t e IC%) shows d e f i n i t e
                                          76
b r i d g i n g of coed g r a i n s by melted e x i n i t e . As a maceral t h e e x i n i t e appeared t o be
l o s t , both with r e s p e c t t o i n c r e a s i n g temperature and c a r b o n i s a t i o n time. I t s d i s -
zppearance a? a recognisable rnaceral would not preclude i t s impregnation i n t o the
                       i
microstructure of remaining c o a l substance. The changes i n the macerdl s t r u c t u r e
were coincident with p o r o s i t y changes. There w a s no s i g n i f i c a n t d i f f e r e n c e f o r
nitroger. and air f l u i d i s a t i o n .

          The p o r o s i t i e s of the chars (Fig. 8) rose s t e e p l y with temperature and
i n c r e a s e d with period of carbonisation.                       In determining the p o r o s i t i e s of c h a r s ,
t h r e e s e p a r a t e types of pores were measured: rounded h o l e s , angular holes and
n a t u r a l holes. It w a s probable t h a t the rounded h o l e s were formed as the gases
r e s u l t i n g from the decomposition of e x i n i t e and v i t r i n i t e attempted t o e s c a p
through the p l a s t i c c r semi-plastic v i t r i n i t e , and t h a t the angular holes were
cracks formed a f t e r carbonisation when the m a t e r i a l contracted on cooling. The
t h i r d c l a s s i f i c a t i o n of h o l e s , n a t u r a l h o l e s , occurred i n f u s i n i t e and semi-fusinite
g r a i n s . The p o r o s i t i e s shorn i n Fig. 8 a r e 'rounded h o l e ' p o r o s i t i e s .

         Table 4 below i l l u s t r a t e s the r e l a t i v e importance of t h e rounded, angular and
n a t u r a l holes i n Calverton coKL0
                                                       TABLE 4
                                    P o r o s i t y Analyses of Calverton Chars


                   Calverton               Rounded           Angular         Natural             Total
                   Bmiri. N~                holes             holes            -
                                                                              holes             p z t g      '
                       350cC                  0.1               1,6             2.4               4.1
                       375OC                  1.4               1.6              1.8              4.8
                       400cC                  0.7               2.2             2-3               5.2
                       425OC                21 -6               3.9             3.0              28.5        I
                       450zC                43.4                3.2             1. I             47.7
                       475 c                51 07               3-5             101              56.3
                       500°C                60.5                2.6              1-0             64.1
                                                                                                        ~~




                   30 nin.
                               N2
                       350°C                  0.4                               1.1         j     305
                       375OC                  0.4                                1.3        I     3.6        j
                       4000C                10.2                                 2.0        j    16.0
                       425uC                32.3         !      4.0              1.9        '    38.1
                       450;C                47.3         '      305              1.2             52.0
                       475 c                52.8         '      3.4             0.3              56.5
                       500°C                59.4                2.6              1.2             63.2
           n a t u r a l l y o c c u r r i n g i n e r t material where over 1% i s p r e s e n t i n t h e
           original coal. Where this n a t u r a l l y i n e r t material is not p r e s e n t , an
                                                                                                                  I
           a r t i f i c i a l a d d i t i v e , e o g o high temperature coke, may be used.
                                                                                                                  1
(ii)       On a commercial s c a l e , sudden or gradual changes of t h e maceral composition




       RFFERFNCES
       Habberjam, G. M.           and Gregory, H. R., Paper t o Fuel Div. A.C.S.,              September, 1962.

       Krtlger, C . , B r e n n s t . Chem., 11/12, 186-189, 1956.

       F i t z g e r d d , D o , Inst. G a s Eng. Comm. 516, November, 1957.
       F i t z g e r a l d , D., Coal and G a s , F e b r u a y , 1958, 60.

       P e m i t i n a , K. S.      Trudy Leb. Geol. Uglya, Akad. Nauk. S.S.S.R.,              6, 144-9, 1956.
                                                                                                                  I
                                                                                                                  1
       Amnosov, I. I. and Amnosova, Y. M.,                   Coke and Chem.,   S.S.S.R.   5,   9-17, 1957.
       Erguh, O'Donnell and P a r k s , Fuel            8 , 205,      1959.                                       I


       T a y l o r , G. H.   , F u e l 6 , 221-355, 1957.
       Otto, G. H.,          J. Sediment. P e t r o l . ,   3 , 30,   1933.
       Delesse, A . ,        Compte6 Rendus,       3, 544,     1847.

(IO)   Glagolev, A. A . ,         Eng. Min.,     m, 399,       19%.
(11) Chayes, F . , P e t r o g r a p h i c modal a n a l y s i s :    an elementery statisticdl
     a p p r a i s a l . N e w Pork, Wiley, 1956.
                                                           131

                                CAF'TIONS TO PHOTOMICROGRAPHS OF CHAR GRAINS

                     Photomicrographs of 30 minute Calverton Chars C.P.S.1855/16

                                        (Magnification approximately X 120)
Photo.
 NO.
  1- 35OoC N2 F l u i d i s a t i o n                                                                                    ,   .

         The exinite appears u n a l t e r e d a t this temperature. The v i t r i n i t e shows cracking
         around the imrt f u s i n i t e mass, which i n d i c a t e s t h a t there may be c o n t r a c t i o n .

  2.     a              Fluidisation

         The e x i n i t e appears u n a l t e r e d except where i t l i e s on t h e m a r g i n s of g r a i n s and
         has been oxidised. The v i t r i n i t e i s cracked, and has f a i r l y wide oxidised
         m a r g i n s extending up the open cracks.

  3.     4W°C N2

         The e x i n i t e i s disappearing, l e a v i n g i r r e g u l a r h o l e s i n the m i c r i n i t e and
         v i t r i n i t e . The megaspore i n the l a r g e r d u r a i n g r a i n h a s become l i q u i d and some
         of i t has migrated t o the edge of the g r a i n , cementing a t r i a n g u l a r v i t r i n i t e
         g r a i n t o it. The m i c r i n i t e and f u s i n i t e a r e u n a l t e r e d , and t h e v i t r i n i t e
         remains angular, with f i n e cracks.

   4.    4OO0C Air

         A l a r g e megaspore has become oxidised and has cracked a w q from t h e d u r a i n g r a i n
         which contains it. Within this megaspore there i s a mall a r e a o f u n o e d i s e d
         v o l a t i l e matter which i s b o i l i n g o f f . There is unolddised e x i n i t e b o i l i n g o f f
         in b o t h durain grains. I n the t r i a n g u l a r g r a i n t h e megaspores have been p a r t i a l l y
         oxidised and the t r a n s i t i o n between v o l a t i l e and non-volatile e x i n i t e i s shown.
         The v i t r i n i t e i s j u s t beginning t o become p l a s t i c enough f o r rounded bubbles t o
         develop i n some of t h e g r a i n s .

   5.    425OC N,
         Most of the e x i n i t e has disa-ppeared. The v i t r i n i t e grains are becoming p l a s t i c ,
         and some g r a i n s are f i l l e d with g a s bubbles. The i n e r t i n i t e s a r e s t i l l unaffec-
         t e d , except by escaping from enclosed v i t r i n i t e and e x i n i t e .

   6.    425OC A i r

         The vitrinite appears t o be considerably more p l a s t i c than i n N2 at this tempera-
         t u r e . The g r a i n s a r e considerably swollen and t h e i r margins an? rounded. There
         i s s t i l l some e x i n i t e present i n the d u r a i n g r a i n . The i n e r t i n i t e s remain as i n
         the 400°C sample. It can be seen t h a t t h e margins of t h e vitrinite g r a i n s are
         s t i l l s e a l e d , s i n c e t h e bubbles have no oxidation r i m s , i n d i c a t i n g t h a t t h e
         m a r g i n s must s t i l l be q u i t e p l a s t i c .

   7.
         The l a r g e durain g r a i n has remained i n e r t , except f o r a v i t r i n i t e band which i s
         b o i l i n g out. The microspores and megaspores have gone, l e a v i n g a s k e l e t o n of
         m i c r i n i t e , which has not even collapsed i n t o t h e space l e f t by a megaspore. The
         pure vitrinite g r a i n s a r e swollen, but the ones shown in t h i s micrograph s t i l l
         have f a i r l y t h i c k walls.
                                                                                                                    I



                                                      132

8.   450°C Air
     Again the decomposition of v i t r i n i t e appears t o be i n a l a t e r s t a g e than in t h e            1
     45OoC N2 chars. Some o f t h e bubbles contain oxidised margins, and some are
     unoxidised, being s t i l l enclosed.                                                                          I



   500OC.N
9. 2
   -
     The vitrinite g r a i n s have become quite rounded, c o n s i s t i n g of a network o f t h i n -
     walled bubbles. Bands of m i c r i n i t e 2 have remained with t h e i r o r i g i n a l
     structure.

1.
 0   ~OOOC   Air

     The s t a g e reached i s very s i m i l a r t o t h a t of the N2 c h a r a t t h i s temperature,
     except for t h e o x i d a t i o n of the g r a i n and pore margins. Again, t h e m i c r i n i t e 2




                                                                                                                1
     and f u s i n i t e appear t o have i t s o r i g i n a l s t r u c t u r e . Most of t h e bubbles have
     been oxidised, showing t h a t t h e s u r f a c e of t h e g r a i n s h a s been broken, and
     t h a t t h e oxidised v i t r i n i t e has become b r i t t l e at t h i s temperatui-e.



ACRNOWLEXMENT

      The work described i n this paper w a s c a r r i e d o u t as p h r t of t h e research
programme of the S c i e n t i f i c Department of t h e National Coal Board. The views
expressed are those o f t h e a u t h o r s , and not n e c e s s a r i l y those of t h e Board.




                                                                                                                I
    1.   350°C




,




    2    350'    .r
              134




4   IOOC Ai
I



                      135




     .
     5    2C
           5
          4'   N2




1.




     6.   425OC Air
                        136




    7.   4 ciooc
           2
                   N2




8        i5OoC   Pu.r
           9.    5 OOOC N2




         IC.    53ooc A i r
    :t




,
   11.     A 420°C
           rrpurefl
           vitrinite
           briquette




1 2.     A 42OoC
         "whole coa1 I I
         briquette
     '139




1




I'
:I
140




          I/
          /




      I
     141




4




'1




I
           ri
           0




,
142
    0
    9




I

        0




            -
            u
            e
            I
            -

            G
            t
             ,
     144




%i
           Selective Chemical Reactions for the Study of Coal Macerals

                   by C. R. Binder, L. J. Duffy and P. H . Given

                           Department of Fuel Technology
                           Pennsylvania State University
                              University Park, Pa.

      That the petrological classification of coal components in four main groups,
known as vitrinite, exinite, micrinite and fusinite, has chemical and physical sig-
nificance, as well as practical importance, is already established. There is
petrographic and palaeobotanic evidence indicating that each of these groups is
complex and that several varieties of each exist, but little chemical work has been
carried out to supplement and consolidate this evidence. Such work is in progress
in this laboratory; so far, attention has been paid mostly to the development of
experimental techniques, but a start has been made in applying them to the study of
vitrinite structure.

      It is obvious that structural differences between two or more "vitrinoids"l
found in the same coal will be more subtle than the differences between, say, vitri-
nite and exinite. A comparison of vitrinoids from different coals but of similar
rank will also require subtle distinctions. If these distinctions can be established
and understood, our understanding of the concepts of rank and metamorphosis should be
strengthened considerably, and knowledge of the relation of constitution to behavior
increased. Research of this kind clearly requires particularly sensitive techniques,
and any chemical reactions used must be as selective and as informative as possible.
In this paper the extension and improvement of two such chemical reaction techniques
are described, together with their application to some purified vitrinitic materials.

Samples Studied.

      I n some of the preliminary experiments designed to elucidate the mechanism of
the dehydrogenation reaction, a sample of vitrain from the Bruceton mine of the
Pittsburgh seam was used. The elementary analysis is shown i Table 1; the petro-
                                                              n
graphic analysis of a block from the same batch of coal is: vitrinite, 85%; semi-
fusinite, 6%; fusinite, 2%; exinite, 4%; micrinite, 2%; and pyrite, 1%.

      The other samples were pure vitrinites separated by float-and-sink techniques
from the bright bands in selected vitrains. Their properties are collected in
       .
Table 1 Samples MP 10a and 10b were taken from different levels in one pillar
section of the same seam, but differ appreciably in reflectance, and represent dif-
ferent vitrinoids in the classification of Schapiro and Gray.'  Samples M P 11 and 17
have similar reflectances and represent the same vitrinoid V 9 according to Schapiro
and Gray; they are, however, of quite different geological age and derived from dif-
ferent types of plant material, since MP 11 is an Appalachian coal laid down in the
Pennsylvanian period of the Palaeozoic and MP 17 is younger, have been laid down in
the Cretaceous period of the Mesozoic (ages approximately 300 and 120 x lo6 years
respectively).

      The hydroxyl contents of the samples are included in Table 1 for completeness;
they are repeated from an earlier publication.3 It seems clear that samples M P 11
and 17 do differ somewhat in elementary analysis, but the carbon content of MP 17
                                                                   146
                                      *
may be somewhat t o o h i g h             .
            The i n f r a - r e d s p e c t r a of a l l four v i t r i n i t e s have been obtained.        The s p e c t r a
of MP 10a and 10b do n o t d i f f e r s i g n i f i c a n t l y , except t h a t a d i f f e r e n c e of t h e
i n t e n s i t y of t h e hydroxyl band a t 3400                i s observed, p a r a l l e l i n g t h e hydroxyl
c o n t e n t s determined chemically.                The s p e c t r a of MP 11 and 1 7 a l s o resemble one an-
o t h e r c l o s e l y ; h e r e a g a i n t h e hydroxyl bands d i f f e r i n i n t e n s i t y , and t h e d i s t r i -
bution of hydrogen between aromatic and a l i p h a t i c s t r u c t u r e s i s e v i d e n t l y somewhat ,
d i f f e r e n t (see Table 3 below).

                                     T a b l e 1.    Analyses of Samples S t u d i e d

Sample         Source seam                  Av. R e f l e c -                              Per c e n t d.a.f.
    No.        and l o c a t i o n        tance i n o i l , %             C          H          N          S          O*   o   as OH

MP l o a       Lower F r e e p o r t
                                                    0.743              82.6         5.4        1.6        1.4        9.0        5.6
               West Sunbury, Pa.
MP 10b         Laver F r e e p o r t
                                                    0.630              83.8         5.3        1.6        1.1        8.2        3.9
               West Sunbury, Pa.
M 11           Upper F r e e p o r t ,
                                                    0.995              84.9         5.2        1.5        08
                                                                                                           .         7.6        3.2
               Maysville, Pa.
M 17
 P             F r e d e r i c k , Valdez,
                                                    0.934              86.6         5.5        1.9        08
                                                                                                           .         5.2        2.0
               Colo.
               Pittsburgh                                              83.6         5.6        1.7        2.0        7.3             -
               Bruceton V i t r a i n
*by   difference

Reduction with Lithium.

            L i t h i u m i n a l i p h a t i c am ies i s a powerful r e i c i n g agent - > r aromatic systems,
naphthalene, f o r example, being reduced t o t h e o c t a - o r deca-hydro d e r i v a t i v e . The
r e a c t i o n proceeds, depending on t h e s o l v e n t , a t 18 o r looo, and breakage of carbon-
carbon bonds, such as o c c u r s i n c a t a l y t i c hydrogenation, i s n o t found. Both e t h y l -
amine4 and e t h y l e n e diamine5,6 have been used as t h e amine component i n t h e a p p l i -
c a t i o n of the r e a c t i o n t o c o a l s ; t h e l a t t e r causes somewhat more e x t e n s i v e r e d u c t i o n
o f t h e coal, but is much more t o x i c and i s impossible t o remove completely from t h e
c o a l a f t e r r e a c t i o n . The e x t e n t of r e d u c t i o n v a r i e s s t r o n g l y w i t h rank, p a s s i n g
through a sharp maximum w i t h v i t r a i n s of about 89% carbon ~ o n t e n t . ~ The s o l u b i l i t y           ,~
of t h e c o a l i n p y r i d i n e i s a l w a y s i n c r e a s e d by t h e r e a c t i o n , and t h e magnitude of t h e
i n c r e a s e v a r i e s w i t h r a n k i n a manner c l o s e l y p a r a l l e l t o t h e e x t e n t of r e d u c t i o n .
The marked v a r i a t i o n w i t h r a n k of t h e e f f e c t s of r e a c t i o n suggest t h a t h e r e we have
one s u i t a b l e t e c h n i q u e f o r i n v e s t i g a t i n g c l o s e d i s t i n c t i o n s among v i t r i n i t i c mate-
rials.

          H i t h e r t o i n t h e s t u d y of t h e r e d u c t i o n of c o a l s , a t t e n t i o n has been c h i e f l y
c o n c e n t r a t e d on t h e v a r i a t i o n of e x t e n t of r e a c t i o n w i t h rank, and l i t t l e work has
been done on t h e chemistry of t h e products.                          One i n t e r e s t i n g p o s s i b i l i t y i s t h e

*    The analyses quoted were made by United Analysts Ltd., E a s t Boldon, Co. Durham,
 England, a l a b o r a t o r y experienced i n c o a l a n a l y s i s , and they a r e b e l i e v e d t o be t h e
 most r e l i a b l e d a t a a v a i l a b l e .       The s a m p l e s have a l s o been analysed i n two o t h e r
 l a b o r a t o r i e s , w i t h r e s u l t s t h a t do not a l t o g e t h e r a g r e e w i t h t h o s e quoted; however,
 t h e s e l a b o r a t o r i e s d i d n o t observe c e r t a i n p r e c a u t i o n s now b e l i e v e d important ( s e e
 Appendix), which were observed by United Analysts.
    s t u d y d hydrogen d i s t r i b u t i o n i n t h e product by nuclear magnetic resonance s p e c t r o -
    scopy. To g e t t h e maximum advantage from t h i s technique, t h e material must be i n
    s o l u t i o n , p r e f e r a b l y i n a s o l v e n t t h a t c o n t a i n s no hydrogen. Deuteropyridine has
    been used f o r t h i s purpose w i t h s o l v e n t e x t r a c t s of u n t r e a t e d v i t r i n i t e s 7 and reduced
    products.8 However, i t is extremely expensive and t h e small p r o p o r t i o n of i s o t o p i c
    i m p u r i t i e s found i n a l l commercial samples i n t e r f e r e s w i t h e s t i m a t i o n of aromatic
    hydrogen i n t h e s o l u t e . W e have now found t h a t 40-75% of t h a t p a r t of t h e r e d u c t i o n
    products of four v i t r i n i t e s s o l u b l e i n p y r i d i n e i s a l s o s o l u b l e i n chloroform. A ,
    l a r g e number of s o l v e n t s have been t e s t e d , most of which d i s s o l v e d v e r y l i t t l e ;
    p i p e r i d i n e , chloroform, dimethylformamide and dimethylsulfoxide d i s s o l v e d s i g n i f i c a n t
    q u a n t i t i e s of product. Deuterochloroform i s r e l a t i v e l y inexpensive, and s i n c e any
    i s o t o p i c impurity i n t e r f e r e s l i t t l e w i t h t h e c o a l s p e c t r a , i t i s an e x c e l l e n t s o l v e n t
    f o r n.m.r. s t u d i e s . So f a r we have only been a b l e t o r u n one spectrum i n t h e s o l v e n t ;
    the r e s u l t i s discussed later.

               Four pure v i t r i n i t e s have been reduced by t h e lithium-ethylamine technique.
    The amount of hydrogen added and t h e s o l u b i l i t i e s of t h e p r o d u c t s i n p y r i d i n e and
    chloroform a r e shown i n Table 2. A l l t h e samples a r e of lower rank t h a n t h a t a t which
    maximum r e d u c t i o n occurs; i t w i l l be seen t h a t t h e p y r i d i n e s o l u b i l i t i e s a r e higher
    f o r t h e two samples of h i g h e r carbon content. Moreover t h e two samples MP loa and
    lob, taken from d i f f e r e n t l e v e l s i n a s i n g l e p i l l a r s e c t i o n of a seam, behave d i f f e r -
    e n t l y ; so a l s o do t h e p a i r of v i t r i n i t e s of t h e same r e f l e c t a n c e b u t from d i f f e r e n t
    seams.       The n i t r o g e n c o n t e n t s of t h e products and t h e weak methyl a b s o r p t i o n band a t
    1375 cm-l i n t h e i n f r a r e d s p e c t r a show t h a t t h e ethylamine i s n o t r e t a i n e d by t h e
    products. Good oxygen balances were a l s o obtained, showing t h a t o x i d a t i o n d i d not
    occur. Some pick-up of oxygen did occur, however, i n some of t h e s o l v e n t e x t r a c t -
    ions.

                                 Table 2.       Reduction of V i t r i n i t e s w i t h Lithium

                                                                                  Reduced V i t r i n i t e s
                                                                     MP 10a          MP 10b          MP 1     1         MP 1 7
    H atoms per 100 C atoms
                                                                         115              87              107               91
    i n product
    H atoms added per 100 C
                                                                          37              11                31              15
    atoms
    Pyridine s o l u b i l i t y , %                                      37              41                61              53
    Chloroform s o l u b i l i t y , %                                    27              18                45              16*
    *Low    s o l u b i l i t y may i n p a r t b e due t o exposure t o a i r .

                The i n f r a r e d s p e c t r a of t h e u n t r e a t e d v i t r i n i t e MP 11, t h e chloroform-and
    p y r i d i n e - s o l u b l e and - i n s o l u b l e p a r t s of t h e reduced p r o d u c t s are shown i n F i g . 2.
    It w i l l be seen t h a t a l l f r a c t i o n s of t h e roduct show i n c r e a s e d a l i p h a t i c C-H
    a b s o r p t i o n a t about 2920 an-' and 1450 cm-p (3.45p and 6.9p), t h e chloroform-soluble
    p a r t showin t h e g r e a t e s t i n c r e a s e . The e x t i n c t i o n c o e f f i c i e n t s of t h e a b s o r p t i o n
    a t 2920 cm-f c a l c u l a t e d from t h e per c e n t transmission and t h e c o n c e n t r a t i o n i n the
    potassium bromide d i s c s (gm./gm.), a r e shown i n Table 3, t o g e t h e r w i t h t h e Har/Hal
    r a t i o s f o r t h e raw coals c a l c u l a t e d from t h e a b s o r p t i o n s a t 3030 cm-l and 2920 c m - 1 .
i   and an assumed Ear/Ea1 = 0.44 (see r e f s . 9-11). The e x t i n c t i o n c o e f f i c i e n t s f o r t h e
    products from d i f f e r e n t c o a l samples a r e approximately c o n s i s t e n t w i t h t h e e x t e n t of
    r e d u c t i o n d e r i v e d a n a l y t i c a l l y . The use of t h e e x t i n c t i o n c o e f f i c i e n t r a t i o s must
    not be pushed t o o f a r a s t h e v a l u e of t h e e x t i n c t i o n c o e f f i c i e n t s i s dependent not
    only on t h e c o n c e n t r a t i o n but a l s o on s t r u c t u r a l f a c t o r s .

          I n t h e s p e c t r a of a l l t h e reduced products, t h e a b s o r p t i o n i n t h e aromatic
     carbon-hydrogen bending region, 650-950 cm-l (11-15p) was c o n s i d e r a b l y weaker than
                                                               148

                        Table 3.       S p e c t r a l S t u d i e s of Hydrogen D i s t r i b u t i o n

                                                                                             V i tri n i t e
                                Sample                                   MP 10a            MP 10b           M 11
                                                                                                             P             P
                                                                                                                          M 17

                              Raw Coal                                     0.32              0.36           0.41            0.34
                              Raw Coal                                     0.11              0.12           0.12            0.16
E2920    (Product)
                              C r u d e Reduction Product                  3.2               2.1            3.5             1.6
€2920 (Raw Coal)
           ,I
                              Pyridine Extract                             3.6               1.5             3.6            1.3
           It                 Pyridine Insolubles                          1.2               0.5             1.2            0.6
           It
                              Chloroform E x t r a c t                     3.6               2.7             3.5            2.2
           I1
                              Chloroform I n s o l u b l e s               1.8               1.6             ---            1.2

t h a t i n t h e u n t r e a t e d c o a l s , and t h e C-H s t r e t c h i n g v i b r a t i o n a t 3030 cm-l could not
b e d i s t i n g u i s h e d a t a l l i n t h e s p e c t r a of any of t h e products but MP 1 7 . A broad band
c e n t e r e d a t 1250 cm-’ and a broad shoulder and 1050 cm-1 were n o t i c e a b l e i n t h e s p e c t r a
of a l l the products.               S i m i l a r but n o t i d e n t i c a l s p e c t r a have been shown previously by
Reggel            &.5 f o r t h e reduced products; t h e s e a u t h o r s do n o t r e p o r t s p e c t r a of s o l v e n t
e x t r a c t s of t h e products.

           The n.m.r. spectrum o f t h e chloroform-soluble p a r t of t h e product of r e d u c t i o n
of sample M 10b is shown i n F i g . 1. Owing t o i n s t r u m e n t a l d i f f i c u l t i e s , it has not
                   P
been p o s s i b l e t o r e - r u n t h i s spectrum nor t o run o t h e r samples o r a s o l v e n t blank.
However, t h e i n f r a r e d spectrum of t h e s o l v e n t showed v e r y h i g h i s o t o p i c p u r i t y and
l i t t l e s i g n of t h e presence of hydrogen. The m o s t s t r i k i n g f e a t u r e of t h e spectrum
i s t h e extremely sharp d o u b l e t a t chemical s h i f t s of 2.87 and 2.95 p.p.m. ( r e f e r r e d
t o tetramethylsilane).                 These peaks a r e i n t h e p o s i t i o n expected f o r hydrogen atoms
on carbon i n the a - p o s i t i o n t o an aromatic r i n g or double bond. Absorption i n t h i s
r e g i o n has been p r e v i o u s l y r e p o r t e d f o r c e r t a i n c o a l d e r i v a t i v e s , and so i t s presence
h e r e i s n o t s u r p r i s i n g . However t h e sharpness and t h e f a c t t h a t t h e area under the
peak i s 5077 of t h e t o t a l a r e a under a l l peaks i s s u r p r i s i n g . As already noted, t h i s
r e s u l t s t i l l awaits checking, but i t i s very d i f f i c u l t t o imagine any p o s s i b l e i m -
p u r i t y t h a t could g i v e a l a r g e sharp peak h e r e b u t no s i m i l a r s h a r p peaks elsewhere.
Other peaks were observed corresponding t o methyl and o t h e r a l i p h a t i c hydrogen (0.87,
1.25 and 1.45-2.0 p.p.m.)                 and aromatic and p h e n o l i c hydrogen (8.06 p.p.m.).

Dehydrogenation

            It i s already e s t a b l i s h e d t h a t much of t h e a l i h a t i c hydrogen i n v i t r i n i t e s and
s p o r e e x i n i t e s i s p r e s e n t i n hydroaromatic rings.12,!3         It has been argued t h a t these
r i n g s p l a y a n important p a r t i n t h e s t r u c t u r a l make-up o f t h e s e m a c e r a l s l 4 and t h a t
they govern much of t h e maceral chemistry. The s t u d y of hydroaromatic s t r u c t u r e s by
dehydrogenation i s t h e r e f o r e important i n any d e t a i l e d s t u d y of macerals, b u t no
f u l l y s a t i s f a c t o r y method h a s y e t been reported.      Peover12 has d e s c r i b e d t h e use of
benzoquinone as a dehydrogenating a g e n t ; i t i s e f f i c i e n t , b u t i n a s i d e - r e a c t i o n ,
which Peover believed t o be a d d i t i o n by a Diels-Alder r e a c t i o n , a c o n s i d e r a b l e pro-
p o r t i o n o f quinone combines w i t h t h e c o a l and cannot be removed. Peover mentions
t h e u s e o f triphenylmethyl p e r c h l o r a t e , but g i v e s few d e t a i l s . Raymond               &.I3
r e p o r t c a t a l y t i c dehydrogenation w i t h palladium on calcium carbonate and o t h e r c a t a -
l y s t s , i n high b o i l i n g s o l v e n t s such as phenanthridine.           This method permits d i r e c t
and a c c u r a t e determination o f t h e hydrogen removed, but i t r e q u i r e s a r a t h e r high
temperature (over 300’C) and there i s a p p a r e n t l y some d i f f i c u l t y i n removing c a t a l y s t
and s o l v e n t i f the p r o d u c t s are wanted f o r f u r t h e r study.
          We have used 3,5,3',5'-tetramethyldiphenoquinone as a dehydrogenating agent for
    the Bruceton vitrain under the same conditions as Peover used for benzoquinone,
    thinking that this bulky molecule would not readily undergo Diels-Alder addition to
    the coal. The spectrum of the product showed little change from the untreated coal,
                                      84)
    except that a band at 1190 cm-I ( . b appeared. This band is in the region expect-
    ed for either ether oxygen or carbonyl vibrations, and suggest some addition of the
    quinone to the coal; however, no carbonyl stretching absorption at 1660-1700 cm-I
    was observed, in contradistinction to the situation when benzoquinone was used.

          We have also used the free radical diphenylpicrylhydrazyl, (C6H5)2.NHN*C6H2
                  is
    (N0~)3~~which reported to be an effective dehydrogenating agent for hydroaromatic
    rings.    The infrared spectrum of the product indicated that some dehydrogenation
    probably occurred, but in most cases some addition of the hydrazyl to the coal took
    place. In one experiment a relatively small amount of the hydrazyl was used; it was
    found that in the ultra-violet gpectrum of the filtered reagent solution after re-
    action the strong band at 3330 A characteristic of the hydrazyl had been completely
    replaced by a band at 3200 A characteristic of its reduction product, the hydrazine.
    We conclude that the reagent does dehydrogenate coal, but not very effectively.

          I is believed that in dehydrogenation with the quinones, the hydrazyl and
           t
    triphenylmethyl perchlorate, the first step in all cases is a transfer of hydride
    ion, H-, from the hydroaromatic system to the reagent. This step would leave a
    carbonium ion, and the first stage of reaction must then be completed by loss of a
    proton, &, so that the net result is elimination of a hydrogen molecule. Further
    hydrogen molecules are removed in the same way until the ring has become aromatic.
    Now some Zarbonium ions are known to be stable, and so it is possible that in the
    reaction of coals a proportion of the H- loss is not followed by elimination of e.
    The carbonium ions in the coal could then react with some species derived from the
    reagent, in an addition reation. For example, if a quinone takes up H-, the hydro-
    quinone mono-anion is formed, and if this reacted with a carbonium ion, a covalently-
    bonded ether would result. If triphenylmethyl perchlorate is the reagent, then a
    coal carbonium perchlorate would result, in which the bonding is essentially ionic.
    We have, therefore, a possible explanation of why all four reagents add to the coal
    to some extent, which in the case of quinones would replace the Diels-Alder hypothe-
    sis. In the case of the perchlorate reaction, it should be possible on the above
    hypothesis to remove the perchlorate ion and a proton from the coal, thus completing
    the dehydrogenation step, by treatment of the product with a suitable base. We have
    investigated the use of triethylamine for this purpose.

          Peover12, and C unningham, Given and Wyss (unpublished observations) found that
    the products of dehydrogenating some British vitrains with triphenylmethyl perchlorate
L
    weighed 30-50% more than the coal originally taken. J. K. Brown (unpublished) found
    absorption in the imfrared spectra of the products characteristic of the perchlorate
    ion, but could find'no sign of the presence of the triphenylmethyl group. W e have
    dehydrogenated the Bruceton vitrain and the vitrinites MF' loa and 10b with the re-
    agent, washed the product thoroughly with acetone, and find the weight increases
    shown in Table 4 . The products were refluxed with triethylamine (b.p. 8 . ' )
                                                                             95C    and
    suffered the losses in weight shown in the Table. It will be seen that with the two
    vitrinites the addition of reagent was relatively small, but nearly the whole of it
    was apparently eliminated by amine treatment.

          In the infrared spectra of all the dehydrogenated products, the aliphatic C-H
    bands at 2920 and 1420 cm-l (3.45 and 6.90~) were decreased in intensity. All the
    spectra showed a broad region of absorption between 1030 and 1120 cm-l (8.9 to 9.7~),
    that is, in the position where the perchlorate ion absorbs strongly. This absorption
    was completely removed by the amine treatment. The products also showed well-defined
,   absorption in the aromatic C-H bending region at 698 and 745 cm-1, which was not re-
    moved by amine treatment. The triphenylmethyl group in the perchlorate and the alcohol
    absorbs strongly at 698 and 753-760 cm-1; in spite of the fact that the second fre-
    quency is somewhat higher than that in the spectrum of the coal products, this suggests
t h a t some triphenylmethyl anion o r t r i p h e n y l methane i s r e t a i n e d by t h e c o a l t On the
o t h e r hand, dehydrogenation w i l l i n c r e a s e t h e a r o m a t i c i t y of t h e coal, and t h i s should
cause increased a b s o r p t i o n i n t h i s g e n e r a l r e g i o n .

    Table 4.         Weight Changes i n Dehydrogenations w i t h Triphenylmethyl P e r c h l o r a t e

                                                       Bruceton v i t r a i n         V i t r i n i t e loa     V i t r i n i t e 10b
                                                                                                                                        ~.
U t . g a i n i n reaction, %                                     36                            16                        18
W t . loss on amine treatment,                                                                  14                        17
                                                                  12
% of w t . of u n t r e a t e d c o a l

           There were i n d i c a t i o n s i n t h e s p e c t r a t h a t v i t r i n i t e MP 10b was somewhat more
e x t e n s i v e l y dehydrogenated t h a n l o a .

           There i s t h e r e f o r e some support f o r t h e s u g g e s t i o n t h a t t h e p e r c h l o r a t e i o n
a t l e a s t i s r e t a i n e d i n t h e c o a l products on carbonium ions which a r e i n t e r m e d i a t e
p r o d u c t s of the dehydrogenation, though perhaps i t should not y e t be regarded as
proved. Amine treatment i s f a i r l y e f f e c t i v e i n removing t h e ion. The m a t t e r i s
under f u r t h e r i n v e s t i g a t i o n .

            As an a l t e r n a t i v e approach t o t h e study of dehydrogenation, we a r e u s i n g C14-
l a b e l l e d benzoquinone, i n t h e hope t h a t a radiochemical d e t e r m i n a t i o n of quinone
r e t a i n e d w i l l permit us t o c o r r e c t elementary a n a l y s e s of t h e products t o a quinone-
f r e e b a s i s . The method w i l l a l s o f a c i l i t a t e study of t h e removal of t h e quinone.

                                      General Discussion and Conclusions

           We b e l i e v e t h a t t h e i n t r o d u c t i o n of chloroform as a s o l v e n t f o r v i t r i n i t e s ’
reduced w i t h l i t h i u m i n an amine r e p r e s e n t s a s i g n i f i c a n t advance, which should
f a c i l i t a t e f u r t h e r study of t h e chemistry of t h e r e a c t i o n and t h e a p p l i c a t i o n of
n.m.r. techniques. It should prove p a r t i c u l a r l y u s e f u l w i t h v i t r i n i t e s of higher
rank than those used here, where higher s o l u b i l i t y i s t o be expected, and on t h e
p r e s e n t evidence t h e s t u d y of t h e r e a c t i o n and i t s products does p r o v i d e a s e n s i t i v e
means of d i s t i n g u i s h i n g between c l o s e l y r e l a t e d macerals.               The s i n g l e n.m.r. spectrum
of a reduced product so f a r o b t a i n e d s u g g e s t s a number of d e t a i l e d i n t e r p r e t a t i o n s
w i t h most i n t e r e s t i n g i m p l i c a t i o n f o r c o a l s t r u c t u r e , but t h e s e w i l l n o t be d i s c u s s e d
u n t i l more d a t a a r e a v a i l a b l e .

            Some c o n t r i b u t i o n t o t h e understanding of t h e mechanism of dehydrogenation
r e a c t i o n s has been made, b u t i t cannot be claimed t h a t a f u l l y s a t i s f a c t o r y procedure
h a s y e t been found. Information merely about t h e amount of hydrogen removable, w i t k
o u t any f u r t h e r study of t h e products, would b e u s e f u l i n t h e study of macerals, and
of t h e methods a v a i l a b l e a t p r e s e n t f o r o b t a i n i n g it, t h e c a t a l y t i c method13 i s                         I
perhaps t h e b e s t .
                                                                                                                                              I‘
            There i s now a v a i l a b l e a f a i r l y d e t a i l e d set of d a t a on two p a i r s of h i g h l y
p u r i f i e d v i t r i n i t i c m a t e r i a l s . It has been e s t a b l i s h e d t h a t between t h e members of
each p a i r t h e r e a r e s i g n i f i c a n t d i f f e r e n c e s i n elementary composition, i n d i s t r i -
b u t i o n of hydrogen and of oxygen f u n c t i o n a l groups, and i n response t o l i t h i u m
r e d u c t i o n . I n t h e case of t h e p a i r s from t h e same p i l l a r s e c t i o n , t h e chemical d i .                        I
f e r e n c e s a r e matched by a d i f f e r e n c e i n r e f l e c t a n c e . The r e f l e c t a n c e s of t h e two
c o a l s of d i f f e r e n t g e o l o g i c a l age do n o t d i f f e r much, but we m u s t conclude t h a t i r -
s p i t e of t h i s the samples a r e of somewhat d i f f e r e n t rank i n a chemical sense. Thi?
a p p a r e n t discrepancy between p e t r o g r a p h i c and chemical rank may be a s s o c i a t e d w i t i .
t h e d i f f e r e n c e i n age and o r i g i n .

           The r e s u l t s throw some l i g h t on t h e problem of t h e h e t e r o g e n e i t y of t h e
 v i t r i n i t e group of macerals, but more d a t a a r e obviously r e q u i r e d b e f o r e f i r m c;
 c l u s i o n s can be s t a t e d .
                                                         151

                                                  Experimental

S p e c t r a . A l l i n f r a - r e d s p e c t r a were run i n a Perkin-Elmer Model 21 Spectrophotometer;
t h e samples were d i s p e r s e d i n K B r p e l l e t s , a blank K B r window being placed i n the
r e f e r e n c e beam. I n order t o o b t a i n r e l i a b l e o p t i c a l d e n s i t i e s , t h e weight of samples
was taken t o t h e n e a r e s t 0.01 mg. on a micro-balance, and t h e window thickness was
measured w i t h a micrometer. Peak h e i g h t s were measured by t h e b a s e - l i n e technique.

      The n.m.r. spectrum w a s r u n on an approximately 2% s o l u t i o n of m a t e r i a l i n
deuterochloroform. A Varian A-60 spectrometer w a s used.
                                                                               4
Lithium Reductions. The procedure previously described was followed; approximately
1 gm. coal samples were taken i n each experiment, and 8 h r s . r e a c t i o n t i m e was allowed.
The e x t r a c t i o n s of t h e products were run on 0.1          -
                                                                  0.2 gm. samples, which were shaken
mechanically w i t h 4-6 m l . s o l v e n t a t room temperature f o r 24 hours. To recover t h e
e x t r a c t s , s o l u t i o n s were evaporated slowly under nitPogen and t h e r e s i d u e s d r i e d i n
vacuum a t 10.     0'

Dehvdrogenations. 3,5,3',5'-TetramethyIdiphenoquinone w a s prepared by t h e o x i d a t i o n
of 2,6-xylenol w i t h benzoyl peroxide i n chloroform.'          I n t h e dehydrogenation r e a c t i o n s ,
0.3 gm. c o a l was r e f l u x e d w i t h 1.2 gm. of the quinone i n 30 m l . dimethylformamide
under n i t r o g e n f o r 5-1/2 hours.

       I n t h e use of d i p h e n y l p i c r y l hydrazyl, 0.1 gm. c o a l w a s r e f l u x e d w i t h 0.3 gm.
hydxazyl i n 30 m l . of e i t h e r p y r i d i n e o r chloroform f o r v a r i o u s l e n g t h s of t i m e up
     4
t o 2 hours.

        The above methods were a p p l i e d only t o t h e Bruceton v i t r a i n .

          The r e a c t i o n s w i t h triphenylmethyl p e r c h l o r a t e were run as f o l l o w s . About 1 gm.
c o a l was r e f l u x e d w i t h 10 gms. p e r c h l o r a t e i n 50 m l . g l a c i a l a c e t i c a c i d f o r 30-35
minutes. A f t e r cooling t h e l i q u i d was poured i n t o acetone ( t o d i s s o l v e t h e t r i p h e n y l -
methane formed and any unchanged p e r c h l o r a t e ) and f i l t e r e d . The r e s i d u e on t h e f i l t e r
was shaken mechanically i n a f u r t h e r 100 m l . acetone f o r 5-8 hours, f i l t e r e d , washed
on t h e f i l t e r w i t h more acetone, and d r i e d . A portionof t h e product (about 0.2 gm.)
w a s r e f l u x e d w i t h t r i e t h y l a m i n e f o r 2 hours; the l i q u i d w a s cooled, and f i l t e r e d ,
and t h e product w a s washed thoroughly w i t h methanol and d r i e d .

                                               Acknowledgements

            The authors are indebted t o D r . W. Spackman and M r . S . Mansfield f o r t h e p r e -
p a r a t i o n of t h e pure v i t r i n i t e s and f o r t h e r e f l e c t a n c e measurements, and t o M r . R.
C. Neavel f o r t h e petrographic a n a l y s i s of t h e Bruceton v i t r a i n .

        They are g r a t e f u l t o M r . N. C . Buckley f o r h i s d e t e r m i n a t i o n of t h e n.m.r.
spectrum, and t o D r . H. G. Richey f o r h e l p f u l d i s c u s s i o n s of t h e r e s u l t . T h i s work
w a s supported i n i t s e a r l y s t a g e s by t h e Coal Research Board of the Commonwealth of
Pennsylvania, and s i n c e January 1963 by t h e Earth S c i e n c e Program of t h e National
Science Foundation.

                                                    References

  1.   P. H. Given, This Symposium, p. 1.

  2.   N. Schapiro and R. J. Gray, Proc. I l l i n o i s Mining I n s t . ,              6 8 t h year, p . 83 (1960).

  3.   Proceedings of Conference on Organic Geochemical Processes, Milan, 1962; t o be
            published, Pergamon P r e s s , 1963.
                                                           152 '

 4.    P. H. Given, V. Lupton and M. E. Peover, Proc. I n s t . Fuel Conf.,                                "Science i n
            t h e Use of Coal", S h e f f i e l d 1958, p. A - 3 8 .

 5.    L. Reggel, R. Raymond, W. A. S t e i n e r , R. A. F r i e d e l and I. Wender, Fuel                          9
            339, (1961).

 6.     I . Wender, R. Raymond and L. Reggel, Paper p r e s . a t t h e 5 t h I n t . Conf. on Coal
             Science, Cheltenham, England, 1963.

  7.   R. A. F r i e d e l , p r i v a t e communication.

 8.    J. F. M. 0 t h and H. Tschamler,                                  1
                                                       Brennstoff-Chem. 4 , 177 (1962).

 9.    J. K. Brown, J. Chem. SOC., 744 (1955).

10.    J. K. Brown and W. R. Ladner, Fuel,                     a     8 7 (1960).

11.    P. H. Given, Chapter XI1 i n "Coal" by W. F r a n c i s , Arnold, London, 1961.

12.    M. E. Peover, J. Chem. SOC., 5020 (1960).

13.    R. Raymond, I. Wender and L. Reggel, Science,                           3.
                                                                              1 7 681       (1962).

14.    P. H. Given, F u e l ,       9427         (1961).

15.    E. A. Braude, J. Brook and L. P. Linstead, J. Chem. SOC. 3574 (1954).

16.    S. T. Cosgrove and W. A. Waters, J . Chem. SOC., 3189 (1949); 388 (1951).

                           Appendix:        Elementary Analysis of Coal Samples

             A s a r e s u l t of e x p e r i e n c e accumulated d u r i n g t h e r e s e a r c h r e p o r t e d here,
w e have r e a c h e d c e r t a i n c o n c l u s i o n s about t h e p r e p a r a t i o n of samples f o r a n a l y s i s
and about a n a l y t i c a l procedure, which we wish t o p l a c e on r e c o r d .

                   1. Samples should b e submitted f o r a n a l y s i s and analysed i n an undried
c o n d i t i o n . The m o i s t u r e c o n t e n t s h o u l d be determined c a r e f u l l y a t t h e same time a s
t h e o t h e r d e t e r m i n a t i o n s , and t h e hydrogen and oxygen c o n t e n t s c o r r e c t e d appropri-
ately.
                       I n c o n d i t i o n s of medium t o high humidity and r e l a t i v e l y low temperature,
w e l l d r i e d c o a l s a r e v e r y hygroscopic and can absorb m o i s t u r e from t h e a i r w h i l e being
handled and weighed.
                  2. F r e s h l y mined samples and samples t h a t have been s e p a r a t e d by f l o a t - a n d -
s i n k i n o r g a n i c s o l v e n t s s h o u l d be thoroughly d r i e d , and t h e n allowed t o come t o equi-
l i b r i u m w i t h moist n i t r o g e n a t a s u i t a b l y c o n t r o l l e d humidity. T h i s p r e v e n t s methane,
s o l v e n t s , e t c . being determined a s m o i s t u r e . The c o n t r o l l e d humidity can be chosen
so t h a t any change of w e i g h t o n exposure t o moist a i r i s slow.

                3. Ash should be determined s e p a r a t e l y , a s i n a proximate a n a l y s i s ; weigh-
i n g t h e r e s i d u e a f t e r t h e combustion f o r t h e C and H d e t e r m i n a t i o n i s n o t r e l i a b l e .
            4. Wherever p o s s i b l e , oxygen should be determined d i r e c t l y ; by comparing
t h e sum of t h e v a r i o u s d e t e r m i n a t i o n s w i t h 100%a v a l u a b l e check on t h e c o r r e c t n e s s
of t h e whole a n a l y s i s i s o b t a i n e d .                                                                               1



                                                                                                                                   ,
t




    80         70          60            50             40                   30           20                 10           0
                                Chemical Shift In PPM from Tetrornethylrilane
         NMR SPECTRUM OF DCCI, EXTRACT OBTAINED FROM Li REDUCED MP-lob
                                    Figure 1
                                                                                                    :I        !


                                                                                                    ri




c
I

i

                         A
                                                                                               -------
                                                        8 PYRIDINE INSOLUBLE FRACTION O LITHIUM REDUCTION PRODU(
                                                                                       F




                                                         C PYRIDINE SOLUBLE FRACTION Of LITHIUM REDUCTION PRODUCT




                     /--7                                D CHCI, SOLUBLE PRAClION OF LITHIUM REDUCTION PRODUCT




           j   i     j    Z     i    i     9    l        o      f        i        l   i    i    3        i        ~   i       s
                                                    Wordengih. Mirroni
                    I SPECTRA OF VlTRlNOlD MP-11 AND ITS REDUCTION PRODUCTS
                    R
                                                   Figure 2

								
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