SECTION A Titanium and the titanium dioxide industry

Document Sample
SECTION A Titanium and the titanium dioxide industry Powered By Docstoc
					                                    SECTION A

               Titanium and the titanium dioxide industry

1. Introduction

Titanium metal (Ti) is the ninth most abundant element found in the Earth’s crust.
Aerospace, sport and medicine are some of the common areas where the metal
has applications, mainly due to its excellent strength to weight ratio and, also,
high resistance to corrosion.
However, the vast amount of titanium is not used in its elemental form, but rather
as the oxide, titanium dioxide (TiO2). In fact the oxide form currently accounts for
over 96% of titanium consumption worldwide [1]. TiO2 has spawned a truly global
industry and is one of the leading inorganic compounds in production today.
Table 1 [2] demonstrates the growth of TiO2 production since its humble
beginnings in 1918.



              Table 1 Global TiO2 Production 1918-1996

              Year       Worldwide TiO2 production / tonnes per
                                        annum
              1918                        4000
              1925                       10,000
              1939                      100,000
              1965                    1,400,000
              1970                    2,000,000
              1985                    3,000,000
              1996                    4,200,000



In the first stage of this interactive unit you will investigate aspects of the titanium
dioxide industry, focusing on technical, economic and environmental issues.
Ultimately, you will debate the merits of industrial development in the UK. For
most of this exercise you will be required to work with colleagues in small sub-
groups. Each member of the sub-group is expected to make an oral presentation
at some stage of the unit.


Note. This teaching exercise uses fictitious organisations and locations to
illustrate recent events and interactions within the UK titanium dioxide
manufacturing industry. Nevertheless, the numbers and facts presented are
reliable and reflect current trends within this important branch of the bulk
chemicals industry.
                                      SECTION B


TiO2 physicochemical properties, product demand and distribution of market
share

   1. TiO2 pigment industry: Physicochemical properties

Titanium dioxide (TiO2) is an inorganic solid with a number of excellent physical
properties, which make it the principal white pigment of commerce. TiO2 is
becoming increasingly dominant over rival white pigments such as white lead,
lithopone and zinc white [8]. Its predominance is mainly attributable to three
important physical characteristics, which are a high refractive index, lack of
colour and chemical inertness.

White pigments are characterised by non-selective light scattering across all
wavelengths of the visible spectrum (see Fig. 4 on the acetate). To achieve
maximum scattering, and ultimately optimal 'hiding' or 'lightening' power, the
pigment must have a high refractive index coupled with the correct particle size
(i.e. high refractive index = high opacity). TiO2 has an exceptionally high
refractive index, higher than any conventional, stable, colourless substance.
Table 2 [8] shows the refractive index and optimal particle sizes of several white
pigments.

  Table 2 Refractive index and optimal particle size for a range of candidate white
  pigments


    Compound            Average refractive       Optimum particle        Relative scattering
                        index vs. vacuum            size (µm)                  power
TiO2, rutile                  2.80                     0.19                  Up to 800
TiO2, anatase                 2.55                     0.24                     600
ZnS, zinc blende              2.37                     0.29                     350
ZnO, zinkite                  2.01                     0.48                     100
(BaSO4, baryte)               1.64                     1.60                      25

TiO2 found in nature is invariably coloured due to the presence of impurities such
as iron and other elements. Processing is necessary to produce pure TiO2. Large
crystals of pure TiO2 are transparent, but when finely ground to optimal particle
size (Table 2) of approximately 0.2 µm they are highly opaque. TiO2 pigments are
distinct from coloured pigments because the latter is characterised by selective
light absorption in the visible spectrum.
TiO2 also exhibits great chemical inertness. It has good heat resistance, with a
melting point of around 1840 oC. TiO2 is also non-toxic, which has seen it
displace white lead (2PbCO3•Pb(OH)2) in paints. White lead is poisonous if
ingested or inhaled and results in the medical condition plumbism, which is
diagnosed when levels of lead in the body are too high [9]. There are a host of
ailments linked to lead poisoning including, mental retardation in children,
epilepsy, memory lapse etc. In addition, white lead reacts with atmospheric sulfur
compounds such as hydrogen sulfide leading to the formation of lead sulfide
(PbS) which is black in colour and so impairs the paint film.

TiO2 is polymorphous, showing three distinct crystalline forms: rutile, anatase and
brookite. Only rutile and anatase are of importance technically and commercially.
These two modifications of TiO2 differ in their basic structures and some physical
properties.

(a) Rutile
The rutile TiO2 form [2, 10] has TiO6 octahedrons that form columns by sharing
two edges. Titanium has six oxygen nearest neighbours, and oxygen has three
titanium nearest
neighbours. Adjacent columns are linked through sharing corners of other
octahedra. The unit cell is shown in Fig. 2 below.
                       2.959 A




                                                                         TITANIUM




                                     4.953 A                             OXYGEN


                       Fig. 2 The Unit Cell of Rutile TiO2

(b) Anatase
The anatase form [2, 10] of TiO2 consists of significantly distorted TiO6
octahedrons where two oxygens are closer to the titanium centre than the other
four. They form eight faced tetragonal dipyramids that come to sharp elongated
points. Each octahedron is seen to share four edges with others. Titanium has six
oxygen nearest neighbours, and oxygen has three titanium nearest neighbours.
The unit cell is shown in Fig. 3 below.
     TITANIUM

     OXYGEN
                       9.514 A




                                       3.758 A
                      Fig. 3 The Unit Cell of Anatase TiO2


Rutile is more closely packed than anatase, which is reflected by their density
values of 4.2 g/ml and 3.9 g/ml respectively [2]. Therefore, the refractive index of
anatase is slightly less than rutile (Table 2). Consequently, anatase shows less
efficient scattering of visible light. In addition, the rutile crystal structure
modification exhibits greater stability than the anatase form. At temperatures in
excess of 915 oC, the anatase form spontaneously converts to the rutile structure
[2]. However, anatase TiO2 is less abrasive than rutile. This is an important
property for pigmentation in materials such as fine paper, ceramics and fibres.

Rutile TiO2 pigments impart greater durability than anatase. This is vitally
important for applications such as paints and plastics. Organic polymers, used as
binders in paints and plastics, are readily broken down by UV radiation when
exposed to weather (i.e. sunlight) [2, 11, 12]. TiO2 absorbs strongly in the UV
region of the electromagnetic spectrum and so TiO2 pigments have a direct
protective effect by absorbing potentially damaging UV. The extent to which the
pigment screens constituent polymers differs for the two crystal types. Rutile TiO2
absorbs UV radiation of wavelength < 400 nm, whereas anatase absorption is <
350 nm (see Fig. 5). Thus, rutile TiO2 offers greater protection against direct
polymer degradation than the anatase form as it absorbs more of the potentially
damaging UV radiation. However, an opposing effect is that TiO2 is a p-type
semiconductor and so absorbed UV can result in electron release and the
formation of positive holes in the crystal lattice. These can migrate to the crystal
surface and, if moisture or oxygen is present, lead to the production of free
radicals such as hydroxy, peroxy and singlet oxygen. Constituent polymers are
susceptible to oxidation by these free radicals resulting in photocatalytic polymer
degradation. The anatase form is a more effective photocatalyst than rutile. In
fact, anatase has been shown to be 10 times more effective at photocatalytic
breakdown of polymers in plastics than rutile TiO2 [2].

Therefore, due to the combination of greater UV absorption and lower
photocatalytic activity, rutile TiO2 is the pigment of choice for high performance
paints such as automotive top-coatings and also for many exterior plastics such
as PVC windows. Chalking, colour fade and loss of gloss are classic signs of
degradation and is a result of pigment being exposed at the film surface [12].



                                     Your Task
 It is your group’s responsibility to present a brief summary of the physical
 properties, structural aspects and important chemistry of TiO2. The following
 points should be covered in your presentation:
 (1) Contrast the physico-chemical properties of TiO2 with other candidate
     pigments and, establish the case why TiO is the a speaker to give your
Once you have considered all the information, 2choose preferred white pigment.
     Fig. 4 should be used in reference to reflectance of visible light. the overhead
presentation. Acetates with the relevant diagrams are available for
projector.
 (2) Using Fig. 2 and Fig. 3 provided, briefly describe the structures of the
     commercially viable modifications of TiO2.

 (3) Using Fig. 5 provided, explain how the structural modifications of TiO2 have
     important consequences for a number of physical and chemical properties.
2. TiO2 pigment industry: Product demand

Table 3 [8] shows 1995 global production capacities for the most important
inorganic synthetic pigments.

Table 3 Global production capacities for the major inorganic synthetic
pigments

 Pigment                          Tonnes per annum           Tonnes per annum (%)
 Titanium dioxide (white)             3,170,000                       66
 Iron oxides (red)                     720,000                        15
 Pigment blacks                        530,000                        11
 Lithopone (white)                      190,000                        4
 Chromate yellow                       145,000                         3
 Others                                  45,000                        1
 Total                                4,800,000                      100

The white pigment titanium dioxide (TiO2) accounted for almost two-thirds of
overall production capacity, translating to 3.17 million tonnes per annum.
Furthermore, TiO2 also dominates the world market for white pigments, with a
75% share [8]. Its predominance is mainly due to a combination of excellent
physical properties, in particular, a high refractive index (conferring high opacity),
lack of colour (i.e. white) and chemical inertness. White pigments such as white
lead, lithopone, zinc sulfide, etc are to a greater extent, being replaced by TiO2.

The main industrial consumers of TiO2 are paints and coatings, plastics and
paper. Other outlets include inks, ceramics, cosmetics, fibres etc. Table 4 [14]
shows the tonnes per annum and % demand of TiO2 attributed to the various
industries in 1996.

Table 4 Major industrial TiO2 consumption

 Consumer industry                Tonnes per annum                       %
 Paints and coatings                  1,881,000                         57
 Plastics                               660,000                         20
 Paper                                  429,000                         13
 Others                                 330,000                         10
 Total                                3,300,000                         100

TiO2 is ubiquitous, finding uses in products such as car paints, PVC windows and
doors, glossy magazines, clothing and even toothpaste. In fact any product
requiring a white or bright coloured surface most likely utilises TiO2 pigments.

The majority of products pigmented with TiO2 are generally considered to be non-
essential, quality of life items. As such, demand for TiO2 correlates well with living
standards in major geographical locations. Living standards can be broadly
measured by GDP (gross domestic product). Figure 8 [2] illustrates the variation
and general rise in demand for TiO2 pigments with world GDP growth between
1980 and 1996.




                                  Fig 8. TiO2 Demand and The World Economy                                   GDP change
                      4.5                                                                                    TiO2 demand
                                                                                          3.5
                        4
                      3.5
  Growth in GDP (%)




                                                                                                World Demand for
                        3                                                                 3
                      2.5
                        2




                                                                                                      TiO2
                      1.5                                                                 2.5

                        1
                      0.5
                                                                                          2
                        0
                      -0.5 1980   1982   1984   1986   1988   1990   1992   1994   1996

                       -1                                                                 1.5
                                                       Year




Figure 8 also highlights the volatile nature of the TiO2 industry. The onset of
global recession in 1989 saw GDP plummet, resulting in excessive TiO2
production capacity relative to demand. This left manufacturers with not only an
over-capacity problem but also a product of reduced value. For example,
between 1989 and 1991 the decline in TiO2 coupled with over optimistic capacity
increases, led to price falls in the US and Germany of 13% and 16% respectively
[15]. Another good indicator of performance of the TiO2 industry is the 'operating
rate'. The operating rate is defined as the percentage of production capacity in
use at any given time. Throughout the 1980's, which was seen as a golden era
by the TiO2 industry, the world operating rate fluctuated between a healthy 92-
97% [16]. However, with the onset of recession this dropped to a low of 85% in
1991 and, more recently 83.5% in 1996. The 1996 rate was attributed to factors
such as customer de-stocking, a drop in demand for paper and increased
competition between manufacturers. These factors effected a sudden slump in
TiO2 price and ultimately curbed the operating rate. Industry concern was evident
with the chairman of SCM, one of the leading TiO2 manufacturers, describing the
1996-operating rate as ‘devastatingly low’ [16]. The operating rate usually
declines through scaling down or even temporary closure of plants.
                                    Your Task

 It is your team's responsibility to present a brief summary of the issues
 concerning TiO2 consumption and demand. Your presentation should cover the
 following points:

 (1) Using the data provided in Table 3, complete Fig. 6 and use it to contrast the
     scale of TiO2 production with that of other major synthetic inorganic pigments.

 (2) Using the data provided in Table 4, complete Fig. 7 and use it to illustrate
     industrial consumption of TiO2 in 1996. Also, highlight some of its many
     everyday uses.

 (3) Using Fig. 8 provided, explain why GDP can be used as an indicator of world
     TiO2 demand. Also, discuss the 'operating rate' in this context.



Once you have considered all the information, choose a speaker to give your
presentation. Acetates with the relevant diagrams are available for the overhead
projector.
3. TiO2 pigment Industry: Distribution of market share [16]

In mid-1996, world TiO2 capacity was 4,193,000 tonnes. The top four
manufacturers were Dupont, Tioxide (ICI), SCM Chemicals and Kronos (NL).
These companies combined accounted for 57% of world capacity.

Dupont: - Production capacity of 909,000 tonnes representing 21.7% of world
total. Majority of plants located in North America (819,000t). Remaining capacity
from plants located in Asia/Pacific (90,000t). No capacity in Western Europe or
Rest of the World.

Tioxide (now Huntsman Tioxide): - Production capacity of 593,000 tonnes
representing 14% of world total. Majority of plants located in Western Europe
(440,000t =74.2%). Remaining capacity from plants located in Asia/Pacific
(58,000t), North America (50,000t) and Rest of the World (45,000t).

SCM (now part of Millennium Inorganic Chemicals): - Production capacity of
505,000t representing 12% of world total. Majority of company's plants located in
North America (307,000t). Remaining capacity from plants located in Western
Europe (119,000t =23.6%) and Asia/Pacific (79,000t). No capacity in Rest of the
World.

Kronos (NL): - Production capacity of 390,000t representing 9.3% of world total.
Majority of plants located in Western Europe (270,000t). Remaining capacity from
plants located in North America (120,000t). No capacity in Asia/Pacific or Rest of
the World.

A host of other smaller manufacturers including Kemira (291,000t), Ishihara
(197,000t), Kerr McGee (173,000t), Bayer (147,000t) etc. combined accounted
for 1,796,000 tonnes representing 43% of world capacity. Majority of plants
located in Asia/Pacific (714,000t) and Western Europe (418,000t). Remaining
capacity from plants located in the Rest of the World (325,000t) and North
America (276,000t).

 Geographically, North America and Western Europe had world capacity shares
of 1,572,000t (37.5%) and 1,310,000t (31.2%) respectively in 1996. Asia/Pacific
and the Rest of the World had lower shares of 941,000t (22.5%) and 370,000
(8.8%) respectively.

Historically, markets in North America and Western Europe enjoyed the best TiO2
growth rates, which explains why almost 70% production capacity was located in
these areas in 1996. However, these two markets have matured and growth has
been modest in comparison to the Asia/Pacific market, where lifestyle is
becoming increasingly westernised. Figure 9 [16] shows the % shift in world
share of the TiO2 market between 1981 and 1995 with respect to major world
geographic regions.
                                Fig 9 % Shift in World Share of TiO2 Market

            38.6
                     35.8

                                        28.2   27.9
                                                                      24.3
  % Share




                                                                                             1981
                                                                                 17.6
                                                               15.6                          1995
                                                                                        12




                 NA                        WE                      A/P             RoW
                                                      Region



Figure 9 illustrates the rapid growth of the Asia/Pacific market, increasing its
world share by 8.7% over the 14-year period. This contrasted with the combined
drop of 3.1% experienced by North America and Western Europe. The Rest of
the World also suffered a decline of 5.6% during this period but this was mainly
attributed to political instability and civil unrest in the region.


Figure 10 [2] shows the growth in demand predicted for each world region
between 1997 and 2000.



               F ig 10 P redicted % G ro w th in T iO 2 D em an d
                                 (1997-2000)


                     RW
            Region




                     A /P

                     WE

                      NA

                            0       1          2       3       4         5   6     7

                                                   % G row th
                                     Your Task

  It is your group's responsibility to present a brief summary of the TiO2 industry
  with respect to major manufacturers and regional markets. Your presentation
  should cover the following points:


  (1) Complete Table 5 on the acetate provided. Use it to highlight major
      manufacturers and their respective world TiO2 capacities. Also comment on
      world capacity share in the major geographical regions.

  (2) Use Fig. 9 on the acetate provided to illustrate the regional shifts in world
      share of the TiO2 market for the period 1981-1995. Also, comment on the
      reasons cited for these shifts with respect to each region.

  (3) Use Fig. 10 on the acetate provided to indicate predicted growth in TiO2
      demand for the major world regions between 1997-2000.




Once you have considered all the information, choose a speaker to give your
presentation. Acetates with the relevant diagrams are available for the overhead
projector.
                                    SECTION C

1. The sulfate process [2, 8, 17]

Nature does not yield titanium dioxide (TiO2) in a form suitable for commercial
use. There are two basic chemical processes exploited by manufacturers, the
Sulfate Process (SP) and the Chloride Process (CP). The SP is a batch process
and is the older of the two methods. The mineral ilmenite or synthetic titanium
slag is available as the raw starting material for the SP.
Ilmenite contains between 43 - 61% TiO2 and 34 - 39% iron oxide. There are
primary and secondary deposits of ilmenite scattered worldwide. However,
manufacturers favour the much more cost-effective secondary deposits. This is
because these deposits are sandy and so much less work is needed to produce
the finely ground raw material necessary for processing. Currently, around 9
million tonnes of ilmenite is mined annually. It is estimated that deposits will last
well into the next century.
Titanium slags are synthesised from ilmenite and typically contain 70 - 85% TiO2.
High TiO2 content is desirable and achieved by carbothermic reduction of iron
within the ore, to the metal, which can then be tapped off as a liquid. The overall
reaction is shown below:

               2FeTiO3 + C                    2Fe + 2TiO2 + CO2

Acid digestion: Finely ground ore is digested in approximately 96% conc.
sulfuric acid. A 60% excess of free acid, based on TiO2 content, is important to
ensure digestion efficiency of around 94%. In addition, the quantity of excess
acid is crucial in optimising pigment-particle size of between 0.1 and 1 µm, after
hydrolysis. An exothermic reaction, initiated by steam or water, occurs at around
100oC producing a sulfate cake. Any undigested ore is filtered off. Scrap iron is
added to reduce any remaining Fe3+ (Comproportionation - Fe + Fe3+ = Fe2+).
Finally, if ilmenite is used as the starting material, cooling to less than 15 oC
crystallises large quantities of iron (II) sulfate heptahydrate (FeSO4•7H2O) out.
The overall reaction is shown below:

           FeTiO3 + 2H2SO4                     TiOSO4 + FeSO4 + 2H2O

Hydrolysis: The titanium-containing digestion product is heated to around 109
o
  C. Hydrolysis occurs yielding a precipitate gel and copious amounts of waste
sulfuric acid. The gel is then washed to remove the majority of the remaining
acid. Seed crystals are added to the gel, which orientates crystal formation
towards anatase or rutile, depending on the final product required. The overall
reaction is shown below:

           TiOSO4 + (n+1)H2O                       TiO2•nH2O + H2SO4
Calcination (drying): The titanium-containing hydrolysed product is thermally
treated in long, rotary kilns. Water is removed between 200-300 oC. At around
480 oC, TiO2 crystals begin to form, growing as the temperature rises. A final
temperature of 800-850 oC results in the anatase form as the final product. For
the rutile form, a final temperature of 900-930 oC is required. Excessive
temperatures will, in both cases, result in larger crystals and poorer physical
properties. The overall reaction is shown below:

                  TiO2•nH2O                          TiO2 + nH2O


Post-treatment: After cooling, the rutile/anatase TiO2 product can be milled and
surface treated to form the TiO2 base pigment specific to its intended application.

The SP can produce both anatase and rutile forms of TiO2, whereas the CP
yields the rutile form only. Products such as fine paper and ceramics require high
performance anatase. Consequently, only the SP can supply these markets.
Setting up a SP plant requires lower capital investment than that of the CP. Also,
operating costs are lower as the energy demands of the CP are around 30 MJ
more per kg of TiO2 produced [18]. Furthermore, starting materials for the SP are
in greater abundance and so cheaper. By-products generated in the SP are
increasingly being utilised so reducing the environmental burden. Waste sulfuric
acid can be recycled and reused for digesting the raw titanium ore. Also, the
large quantities of iron sulfate heptahydrate can be decomposed into sulfuric acid
and iron oxide, the latter having applications in the construction industry – e.g. in
cement.

Although the benefits of the SP are evident, there are two major drawbacks. First,
as already mentioned, there is an increasing environmental burden with the SP
due to the large quantities of waste generated. Secondly, the SP is a batch
(closed) process, which is not synonymous with industrial scale production. In a
batch process, materials are charged to a reaction chamber and removed once
the reaction is complete. Batch operations are mainly used for small quantity
products such as the manufacture of pharmaceuticals. Consequently, the
production capabilities of the batch SP are limited. In contrast, the CP is a
continuous (open) process, which is the chosen method for most large volume
processes.
                                     Your Task

It is your group's responsibility to present a brief summary of the Sulfate Process
to the other sub-groups. The following points should be covered in your
presentation:


(4) A summary of the raw starting materials available to the SP.

(5) Give a brief technical description of the SP using Fig. 11 (flow diagram) and
    chemical equations.

(6) Advantages and disadvantages of TiO2 production using the SP.

(7) With reference to (3), briefly describe the limitations of the SP as a batch
    process.


Once you have considered the information, choose a speaker to make your
presentation. An acetate for the overhead projector showing an incomplete SP
flow diagram is available.
2. The chloride process [2,8,17]

Nature does not yield titanium dioxide (TiO2) in a form suitable for commercial
use. There are two basic chemical processes exploited by manufacturers, the
Sulfate Process (SP) and the Chloride Process (CP). The CP is a continuous
process, and the newer of the two methods. Natural rutile, synthetic rutile, or
titanium slag is available as the raw starting material for the CP. Also, vast
anatase deposits have been discovered in Brazil and may be used in the future.

Natural rutile is found in river, coastal and dune sands. Typically, it has TiO2
content of 90-98%. This high TiO2 content is desirable, making natural rutile a
very efficient raw starting material. The main deposits of rutile are in Australia,
US, Brazil and South Africa. Approximately 500,000 tonnes are mined annually.
However, supply is scarce and predicted to run out in less than 100 years.
Synthetic rutile is extracted from the titanium ore, ilmenite. It has TiO2 content of
85-90%. It is produced by removing iron from the ore, in the form of a salt
solution requiring work up, or as a valueless oxide. Around 9 million tonnes of
ilmenite is mined annually and supply is expected to last well over a hundred
years.
Titanium slag is also synthesised from ilmenite and typically contains 70-85%
TiO2. The chloride process usually requires TiO2 content >90%. However, the
scarcity of natural rutile and indeed its high cost has forced some manufacturers
into using slag. Allowances must then be made for increased formation of
impurity metal chlorides. Slag formation is achieved by carbothermic reduction of
iron within the ore, to the metal, which can then be tapped off as a liquid. The
overall reaction is shown below:

               2FeTiO3 + C                    2Fe + 2TiO2 + CO2

Formation of metallic iron as a by-product is both economically and ecologically
more interesting than those produced generating synthetic rutile. Consequently,
many synthetic rutile production plants have closed down.

It is vitally important that all traces of water/moisture are removed from reactants
in the chloride process. This is necessary as water reacts vigorously with TiCl4,
generating HCl gas as shown in the equation below:

               TiCl4 + 2H2O                            TiO2 + 4HCl

Chlorination: After thorough drying, the titanium ore is heated in a stream of
chlorine gas and in the presence of coke. The reaction is exothermic but more
heat is generated by the reaction of coke with added oxygen. This maintains the
reaction temperature at around 950 oC. The gas liberated from the chlorinator
contains titanium tetrachloride vapour, carbon monoxide and other impurity
chlorides. The overall reaction is shown below:
                     TiO2 + 2Cl2 + C                  TiCl4 + CO2

Condensation/purification: The gaseous mixture is cooled to condense out
heavy, volatile impurities. Most impurities are removed by distillation. However,
vanadium chloride, which can be present as an impurity, has a similar boiling
point to that of titanium tetrachloride. Therefore, it is necessary to reduce the
vanadium impurity (with gaseous hydrogen sulfide) to a lower valency, which can
then be separated off.


Oxidation: The purified TiCl4 is burnt with oxygen gas at a temperature around
1000 oC to ensure efficiency of reaction. TiO2 in the rutile form is generated. In
addition, chlorine gas is liberated, which can be reused to chlorinate the raw
starting material. The overall reaction is shown below:

                        TiCl4 + O2                  TiO2 + 2Cl2

Post-treatment: Finally, the TiO2 product can be milled and surface treated to
form the base pigment specific to its intended application.

Although limited to rutile production, the CP can generate a high quality product,
free from anatase contaminants. Although the SP can produce both anatase and
rutile forms of TiO2, this may lead to the desired product being contaminated with
the unwanted form. Ultimately, this will impair the performance of the TiO2
pigment. The CP supplies pigments for normal quality paper, paper laminates,
plastics, paints etc. Also, the CP generates significantly less waste compared to
the SP, which means waste disposal/recycling is of more concern to SP
operators. Setting up a CP plant requires a greater capital investment than for a
SP plant. Additionally, running costs are higher due to greater energy demand
(an extra 30 MJ per kg of TiO2 produced). Furthermore, the favoured starting
material for the CP is natural rutile but is more costly for TiO2 manufacturers due
to its relatively low abundance. However, these negative economic factors are
greatly compensated for by considering the favourable production economics of
the continuous (open) CP compared to the batch (closed) SP. Most large
volume industrial processes operate with continuous feed and form products
continuously. Hence, the CP has huge production capabilities. In contrast, batch
processes are synonymous with low volume production (e.g. production of
pharmaceuticals).
                                    Your Task

It is your group's responsibility to present a brief summary of the Chloride
Process to the other sub-groups. The following points should be covered in your
presentation:

(8) A summary of the raw starting materials available to the CP.

(9) Give a brief technical description of the CP using Fig. 12 (flow diagram) and
    chemical equations.

(10)   Advantages and disadvantages of TiO2 production using the CP.

(11) With reference to (3), briefly describe the advantage of the CP as a
   continuous process.



Once you have considered all the information, choose a speaker to make your
presentation. An acetate for the overhead projector showing an incomplete CP
flow diagram is available.
3. Environmental issues

Large quantities of waste products discharged from TiO2 plants has led to the
industry as a whole being singled out for special attention by government
environmental agencies. Underpinning this was legislation introduced in 1978 by
The Council of European Communities (78/176/EEC) [19], with the sole aim of
reducing and monitoring discharges from TiO2 plants. This directive has been
amended several times to further reduce the environmental burden.

Effluent discharges affected by regulations

Liquid - discharge of acidic wastes, and solutions containing soluble heavy
metals (mercury, lead, cadmium etc.) into surface waters. There are also
regulations controlling underground injection wells.

Gaseous - acid mist, sulfur oxides (SO2, SO3)

Solid - Solid waste landfills (ferrous sulfates, metal chlorides etc.) and toxic
substances (mercury, lead, cadmium etc.)

There are a number of contributory factors, which will influence the overall
environmental impact felt from any TiO2 manufacturing plant. The type of process
and feedstock used will determine the nature and quantities of by-products
generated. Also significant are the recycling and waste disposal procedures
employed.

Two commercial routes are currently available for the manufacture of TiO2
pigments, the sulfate process and the chloride process. Both technologies are
similar in that they are used to extract TiO2 from a variety of natural or synthetic
minerals to form the basic pigment particle. However, the two processes are
distinct when viewed from an environmental standpoint.


The sulfate process [2,8,17]

The sulfate process has natural ilmenite or synthetic titanium slag as its
feedstock, with TiO2 content of 43-61% and 70-85% respectively. The quantities
of by-products decrease with increasing TiO2 content, making slag a much more
efficient feedstock. Three main reactions characterise the sulfate process:

(1) Digestion -     FeTiO3 + 2H2SO4                   TiOSO4 + FeSO4 + 2H2SO4

(2) Hydrolysis -    TiOSO4 + (n+1)H2O                 TiO2•nH2O + H2SO4

(3) Calcination -   TiO2•nH2O                          TiO2 + nH2O
Depending on the feedstock, each tonne of TiO2 produced by the sulfate process
generates approximately eight tonnes of very dilute sulfuric acid, which can either
be re-concentrated for reuse in the digestion step or neutralised using limestone
(Ca2CO3) to form gypsum, which is mostly land-filled. However, some companies
have been, to a greater extent, marketing gypsum for use in plasterboard, paper
and cement industries. In addition, 2.3-2.7 tonnes of mainly crystalline iron
sulfate (FeSO4•7H2O) is generated, which can be converted to iron (III) sulfate,
which is used in the water treatment industry [8].

The chloride process [2, 8, 17]

The chloride process has natural rutile, synthetic rutile or titanium slag as its
feedstock. TiO2 content in each is 90-98%, 85-90% and 70-85% respectively.
Again, the quantities of by-products formed vary with TiO2 content. Two main
reactions characterise the chloride process:

(1) Chlorination -   TiO2 + 2Cl2 + C                   TiCl4 + CO2

(2) Oxidation -      TiCl4 + O2                        TiO2 + 2Cl2


The raw TiCl4 produced in the chlorination step must be purified before oxidation.
Purification yields 0.4-0.9 tonnes of by-products, again dependent on the
feedstock used. These by-products are mainly impurity chlorides resulting from
chlorination of non-titanium components of the feedstock. This waste is disposed
of as is, or neutralised and land-filled. Impurities apart, all chlorine used is
recaptured and recycled in step (1).


Life cycle assessment [18]

TiO2 manufacturers are, to a greater extent, realising that the environmental
impact of any potential future development must be rigorously assessed to
ensure productivity within limited investment capital margins. Life Cycle
Assessment (LCA) is a method used to determine the environmental effects
related with a given product. The assessment covers the entire life cycle of the
product, which includes extraction of primary raw materials and, also product
manufacture, use, and eventual disposal. Data are gathered about all raw
material input, energy consumption, products and wastes from each link in the
manufacturing chain. Once collected, the data is fed into the appropriate
computer package, which calculates the environmental burdens associated with
the product life cycle. LCA has been applied to TiO2 pigment manufacture in
order to assess the environmental burdens associated with a number of different
processing options. Table 6 shows five such options.
Table 6 TiO2 pigment processing options

 Option      Feedstock               Process                 Waste Treatment
   A          Ilmenite                Sulfate                        None
   B          Ilmenite                Sulfate           Neutralisation to EU standard
   C            Slag                  Sulfate               Acid reconcentration
   D            Slag                 Chloride                   Neutralisation
   E       Synthetic Rutile          Chloride                   Neutralisation

    The problem of what aspects of environmental performance to measure is
      simplified by focusing on two major environmental yardsticks - energy
                             consumption and waste.
  Table 7 shows the LCA results for each processing option. The data, comparing the different
  processing options with respect to each environmental measure cited, is also presented
  graphically in Figs. 13, 14, 15 and 16 (acetates).


  Table 7 LCA results for various processing options


             Gross            Sulfur
                                                                    Liquid (acid + trace
            energy         oxide (SOx)       Industrial solid
 Optio                                                              metals) discharges
            demand          emissions            wastes
  n                                                                       to water
             (MJ/kg           to air           (kg/kg TiO2)
                                                                       (kgH+/kg TiO2)
              TiO2)        (kg/kg TiO2)
   A            72            0.100                  0.5                     0.025
   B            75            0.056                  1.8                    0.0125
   C           103            0.050                  0.8                    0.0151
   D           107            0.076                  1.0                    0.0027
   E           100            0.090                  2.4                    0.0034

The results demonstrate that LCA can give an insight into the relative
environmental merits of both TiO2 manufacturing processes. For example, the
‘gross energy demand’ chart (Fig. 13) shows that the chloride processing option
requires around 30MJ more energy per kg of TiO2 produced. Additionally, there is
also clear evidence of the impact of waste treatment options. For instance, option
A and B are both the same with regard to process type (sulfate) and raw material
(ilmenite). However, A has no waste treatment but B has neutralisation to EU
standard. The ‘liquids discharges to water’ chart (Fig. 16) clearly demonstrates
the positive effect of the EU regulations – i.e. liquid discharges are effectively
halved in B compared to A.

LCA is viewed as a useful aid to providing the information TiO2 manufacturers
need in order to improve their environmental strategy. However, it must not be
viewed as an exact science, as the optimum manufacturing configuration is
invariably site specific. Factors such as chlorine and sulfuric acid availability, type
of titanium feedstock, community environmental awareness and outlets for co-
products (e.g. gypsum) are all determinants. LCA may be considered part of a
comprehensive environmental strategy.


 Your Task
 It is your group’s responsibility to present a brief summary of the environmental
 issues surrounding TiO2 manufacture to the other sub-groups. The following
 points should be covered in your presentation:
 (12) Summarise the legislation imposed on TiO2 manufacturers in Europe.

 (13)   Comment on quantities of waste generated in the SP and CP.
  Once you have considered all the information, choose a speaker to make your presentation.
 (14) Explain the concept of LCA and, with reference to the charts provided
  Acetates with the relevant diagrams are available for the overhead projector.
    (Figs. 13, 14, 15 and 16), discuss how it may be applied to TiO2 pigment
    manufacture.
                                   SECTION D


   1. Titanium dioxide company

Your team is on the board of the UK based company Titox Plc, one of the leading
manufacturers of TiO2 worldwide. Titox Plc has a responsibility to protect the
interests of investors and shareholders alike. Also, the company is duty bound to
make every effort to minimise any negative environmental impact resulting from
its operations.

The company has recently announced plans to increase its world capacity in line
with predicted long-term growth in market demands. It intends to build a chloride
process plant at a cost of £50m. The new plant will be capable of producing
50,000 tonnes per annum of rutile TiO2 and will create around 250 new jobs. This
figure could rise significantly with predicted future investment. Titox Plc has
identified two possible sites for the new plant, one in eastern China and the other
on the West Coast of Scotland. A range of criteria has been used to rate each
site against. These include availability of chlorine, the ease of import/export of
bulk materials (feedstock, TiO2 product etc.), energy costs, road/rail links etc.
After careful consideration, Titox Plc initially favoured the Scottish site but then
admitted that the China site was very attractive as it would offer the company
further penetration into the rapidly expanding Asia/Pacific market. Currently, TiO2
consumption per capita in China is 0.15 kg/year [20], significantly lower than the
Western European figure of 4 kg/year. In fact, China is expected to show the
greatest increases in TiO2 consumption over the next 10 years worldwide.
Furthermore, labour costs would be significantly reduced at the China site.

As members of the board, your initial tendency towards the Scottish site was
heavily criticised by some of the company's major investors. They cited excellent
growth prospects and significantly cheaper labour costs as two major reasons
why investing in the Asia/Pacific region made sound business sense. It was also
been suggested by some that the Asia/Pacific investment would not be subject to
the same level of environmental legislation as the Scottish site. Most
governments in the Asia/Pacific region are seen to be much more manufacturer
friendly with regard to the environment. In contrast, the UK is party to the 1978
EEC directive and later amendments, aimed specifically at reducing and
monitoring pollution from the titanium dioxide industry. This legislation has
dramatically increased production costs for TiO2 manufacturers in the EU.
Another major concern for Titox Plc and the proposed investment in Scotland is
the negative publicity surrounding the company owing to the involvement of the
UK environmental group Greenwatch. Their organisation is deeply concerned
that the investment in Scotland presents a serious threat to the local
environment, not least to the health and safety of the residents in the adjacent
town of Bankside.
The town of Bankside was built up around shipyard docks dating back to the mid-
1800's. The shipyard was the major employer in the area but the shipbuilding
industry has been in steady decline over the past 40 years. The local MP is up for
re-election and is very keen on the Titox Plc investment, as it will help reduce the
worryingly high levels of unemployment in Bankside. Furthermore, the MP
recognises the jobs created by the potential investment will be of high value and
so more secure in the event of an economic downturn. This is important, as the
town has witnessed a number of transient investments, which offered very little in
terms of job security. However, much to the dismay of the MP, the campaign
being waged by Greenwatch in the town has raised fears among local people
about the siting of a chemical plant in their area.

The Greenwatch campaign has highlighted the vast amount of waste generated
by TiO2 manufacturers. The group has raised concerns about the dumping of
acidic effluent into rivers and coastal waters. Their literature contains research
indicating that this dumping practice has serious consequences for marine life
[21]. In addition, they suggest that toxic metals contained in the effluent such as
arsenic, mercury, lead and cadmium may well breach into the human food chain.
However, Greenwatch has admitted that such problems are mainly attributable to
plants utilising sulfate technology. Titox Plc has proposed the use of the
environmentally superior chloride technology and so this aspect of the
Greenwatch campaign is flawed as far as your company is concerned. Much
more damaging, has been their focus on two recent environmental failures at
Titox Plc’s Deeside facility.

Firstly, in June 1997 [22] the Deeside plant was served with a prohibition notice
by the Environment Agency (EA), which led to partial closure of the facility. A
quantity of toxic titanium tetrachloride (TiCl4) leaked and subsequently reacted
with cooling water giving rise to a dense white plume consisting of hydrochloric
acid mist and fine particles of TiO2. The police took the precaution of sealing off a
road adjacent to the plant and also advised local residents to stay inside and
close all windows and doors. Although greatly concerned by the incident, Titox
Plc was happy to report that there were no injuries on site and none recorded off
site. In fact, the all clear was given less than one hour after the leak occurred
such was the rapid response of the company to the incident. The prohibition
notice was lifted five weeks later following repairs and a thorough review of
maintenance and operating procedures at the plant.

Secondly, another incident occurred at the same Deeside plant in February 1999
[23]. 8,000 tonnes of effluent, containing 37 tonnes of concentrated hydrochloric
acid escaped from a damaged pipeline onto protected marshland near to the
plant. Approximately 70,000m2 of marshland was affected by the leak. In the
immediate aftermath, a clean up team pumped large amounts of seawater into
the affected region to dilute the acid from a pH of 1 to 2.5. Clean up work
continued for some weeks afterwards to help return the pH to normal levels of
between 5.5 and 6. Titox Plc spent in excess of £35,000 on the clean up
 operation and, although there was considerable effects on some invertebrate life,
 independent scientific evidence showed that there had been no adverse affect on
 wildlife as a result of the incident. The company expressed its deep
 disappointment over the leak, alluding to the fact that over the years it had spent
 a considerable amount of time and money developing the marsh. Titox Plc
 pleaded guilty in court to the charges brought against it by the EA, resulting in a
 total fine of £150,000.

 Titox Plc are angered by Greenwatch's campaign as there is no recognition of
 the positive strides that you feel the company has taken on environmental issues.
 For example, Fig. 17 [25] shows the environmental burdens resulting from the
 company's operations for 2000, relative to the baseline year, 1995, and to 1999.
                                    Ozone Creation
                                       100

                       Oxygen                           Global
                       Demand                           Warming
                                                                     1995
Fig 17 Titox plc                         0
                                                                     2000
environmental
                                                                     1999

                      Ecotoxicity                     Acid Gases
                                                                   Indexed:
                                    Acids to Water                 1995 = 100

 Environmental burden is a method used to assess the potential harm to the
 environment of Titox Plc's chemical emissions. It links them to real environmental
 issues and so helps to clarify their potential environmental impact. The graph
 clearly shows that since 1995 the company has made good progress in reducing
 nearly all burdens reported, mostly by about 40-50%. The exception to this is
 global warming where the reduction is less than 1%, in part due to increased
 production, and thus increased energy consumption, over the time period
 covered.
 Titox Plc places great importance on communities next to its sites [25]. The
 company and its employees get involved in many local projects. For instance, in
 Deeside a forward-thinking initiative titled Children Challenging Industry has been
 developed by Titox Plc in partnership with the UK government and the Deeside
 Education Action Zone. It gives children the opportunity to see how the chemical
 industry really works. Your company feels that campaigns, such as Greenwatch's
 in Bankside, makes the task of developing community-industry projects all the
 more difficult.

 Deciding which site to invest in is not clear-cut. Investor pressure and
 environmental issues may have shifted the balance in favour of the Asia/Pacific
 investment. However, your company has a well-established technical base in the
 UK, which will give the Scottish site advantages over the China site with respect
 to setting up, manufacturing and maintenance procedures. In addition, the UK
boasts a robust and stable economy, so providing a steady platform for industrial
growth. Many analysts argue that the economy in Asia/Pacific is much more
insecure than its UK counterpart. They point to the devastating collapse of the
economy there, in the second half of the 1990's, as clear evidence.

Finally, Titox Plc is very keen to find out from Scottish Development International
(SDI) [26] what benefits the company could expect by investing in Scotland. This
body works on behalf of Scottish Enterprise and the Scottish Executive, with the
aim of attracting new investment into Scotland and also providing support for
those already here. A team representing SDI will provide your board with the
information it requires. Your board should then be in a position to decide whether
or not Titox Plc will locate in Scotland.

                                     Your Task
 As board members of Titox Plc, your team should present a brief summary of the
 company's position with regard to the new investment proposal. You may want to
 structure your presentation with the following points in mind:

 (1) Indicate your major responsibilities as board members of Titox Plc.

 (2) Discuss the economic and environmental pressures that will influence your
     decision on which site to invest in.

 (3) Greenwatch will criticise Titox Plc's environmental record. You must defend
     the company on this issue. This is also an opportunity to win over the
     residents of Bankside. the information, choose a speaker to give your presentation.
  Once you have considered all (Fig. 17 is available on acetate).
  The relevant acetates are available for the overhead projector.
 (4) In what areas might Titox Plc expect to receive support from SDI?
2. Regional Development Group

Your team represents the inward investment section of Scottish Development
International (SDI) [26]. The body is a recent Scottish Executive initiative and
works in close partnership with Scottish Enterprise. The task of SDI is to attract
new international companies to Scotland, and also to make their investments in
Scotland as smooth and successful as possible. Hence SDI has a major role to
play in maintaining and developing the Scottish economy. SDI has recently been
approached by Titox Plc which is keen to find out what benefits would be
available to the company if it were to invest in Scotland.

Titox Plc is a UK based company and also one of the leading manufacturers of
TiO2 worldwide. The company has announced plans to increase its world
capacity, in line with predicted long-term growth in market demands. It intends to
build a chloride process plant at a cost of £50m. The new plant will be capable of
producing 50,000 tonnes per annum of rutile TiO2 and will create around 250 new
jobs. This figure could rise significantly with predicted future investment.

Titox Plc has identified two possible sites for the new plant, one in eastern China
and the other on the West Coast of Scotland. A range of criteria has been used
to rate each site against. These include availability of chlorine, the ease of
import/export of bulk materials (feedstock, TiO2 product etc.), energy costs,
road/rail links etc. After careful consideration, Titox Plc initially favoured the
Scottish site but then admitted that the China site was very attractive as it would
offer the company further penetration into the rapidly expanding Asia/Pacific
market. Currently, TiO2 consumption per capita in China is 0.15 Kg/year [20],
significantly lower than the western European figure of 4 Kg/year. In fact, China is
expected to show the greatest increases in TiO2 consumption over the next 10
years worldwide. Also, labour costs for the company would be significantly less
with respect to the China site.


The Scottish site is situated next to the town of Bankside, which was built up
around shipyard docks dating back to the mid-1800's. The shipyard was the
major employer in the area but the shipbuilding industry has been in steady
decline over the past 40 years. The local MP is up for re-election and is very
keen on the Titox Plc investment, as it will help reduce the devastatingly high
level of unemployment in Bankside. Furthermore, past investments in the area
have been transient with various overseas companies creating mainly low value
jobs, which tend to be highly susceptible in times of economic recession. In
contrast, the Titox Plc investment offers high value and, consequently, more
secure jobs in the area. SDI recognises the importance of this potential
investment and views it as a major step towards improving both economic and
social conditions in Bankside. As such, SDI must convince Titox Plc that locating
in Scotland presents an excellent investment opportunity for the company.
Scotland boasts a reasonably well-developed chemical industry comprising
many of the world's leading companies. The principal chemical companies in
Scotland are listed in Table 8 [26].

Table 8 Major chemical companies in Scotland

BP                           GE Plastics                   Quest International
BPI                          GlaxoSmithKline               Rhodia Chirex
Ciba Specialty               ICI Nobel Enterprises         Roche Vitamins (UK) Ltd
Chemicals                    ISP Alginates                 Rohm & Haas (Scotland)
Diosynth                     Macfarlan Smith               Sigma Aldrich Co
Du Pont – Teijin Films       Norit UK Limited
Elementis Specialities       Organon Laboratories          Syngenta
Enichem UK Ltd               PET Processors
Exon Mobile

SDI is aware that many of these companies conduct high value research and
development outwith Scotland. However, Titox Plc is an UK company and has its
technical base well established here. The company’s planned investment would
require substantial research and development facilities, which is all the more
reason for SDI wanting Titox Plc to commit to Scotland.
Collectively, the chemical industry in Scotland is responsible for employing over
27,000 people both directly and in support activities. The importance of the
chemical industry here is clearly illustrated by the fact that chemical exports from
Scotland account for some two thirds of the UK total, amounting to a massive
£1.7 Billion per year (NB this figure is inclusive of North Sea oil and gas) [26].
Thus, chemicals are a major component of Scotland's technical manufacturing
and commercial base. Scotland's dedication to the chemical industry is not in
doubt, which should reassure potential investors such as Titox Plc.

Scotland offers a wide range of financial incentives for inward investors, which
can significantly offset the costs of relocation and expansion [26]. If Titox Plc
were to invest in the Scottish site, it would be eligible for a Regional Selective
Assistance (RSA) grant as Bankside has been classified as an 'Assisted Area'
due to the depressed state of the local economy. This grant is negotiable and is
based on a percentage of fixed capital costs as well as the number of jobs
created. Typically, RSA grants for projects in assisted areas can be in excess of
one third of the cost of new investment. Furthermore, RSA grants can be
awarded for follow up projects and so once established in Bankside, any further
expansion of the site by Titox Plc would be eligible for support. In addition to RSA
grants, Local Enterprise Companies in Scotland offer 'Property Support Grants'.
Such grants are available to inward investors to support upgrades, or required
refurbishment and fit out on the chosen property.
Another financial incentive offered to inward investors in Scotland is 'Training and
Employment Grants'. These are designed to help companies with the costs of
training and retraining of employees. Typically, a grant can cover up to 50% of
training costs relating to expenditures such as tuition, materials, travel and
accommodation.

Finally, the 'New Deal' and 'Jobseekers' government initiatives encourages
employers to recruit young people in the age brackets 18-24 and 25 plus
respectively. For example, under the New Deal initiative, full time employment of
a young person would attract a subsidy of £60 per week for six months, and also
£750 towards training costs [26]. Under the scheme, companies have the added
benefit of being able to choose their own candidates.
SDI recognises that each inward investment project has specific requirements.
With this in mind, the SDI ‘chemicals’ division would already have in place a
financial package designed to meet the needs of Titox Plc. The package would
be based around information on planned investment, jobs, location and time
frame.

Companies are acutely aware that the success of any new investment depends
greatly on the quality of the workforce in the area. The Scottish workforce has a
worldwide reputation for excellence and explains why Scotland is home to over
1,000 overseas-owned facilities covering most industrial sectors. There is a
wealth of both professional and non-professional labour, which is easily
accessible via Government job centres, specialist recruitment agencies and
media advertising. Scotland’s long history in the chemical industry gives
employers in this sector the luxury of choice when recruiting for a wide range of
specialist vacancies. This is mainly down to heavy investment in education
programmes that have strong links with the industry. A total of 13 universities, six
specialist higher education institutions and 47 colleges of further education,
spawn a steady flow of graduates with scientific and technical skills designed to
meet companies’ individual needs. Although highly capable, Scotland’s workforce
still remains cost-effective. Scottish hourly wage costs, including indirect social
wage costs (e.g. National Insurance), are lower than in most other European
nations [26]. Also, Scottish wage and salary costs can be as much as 6% less
than the UK average. Furthermore, Scotland outperforms the UK average for
manufacturing gross value added per head. For example, in 1996 this value was
8% up on the UK as a whole [26]. Flexibility is also evident in the Scottish
workforce. It has long embraced shift-working and continuous production
practices to meet employers’ operational requirements. SDI feels that Titox Plc
would benefit greatly from a highly trained, cost effective and flexible workforce if
it were to invest in Scotland.

Excellent transport and communications are vital if a company is to operate
outside its local market. Titox Plc will target the UK and European market if it
decides to invest in Scotland and so would require a fast and efficient transport
network in and out of the region. This would be necessary not only to facilitate
exportation but also to receive the various materials necessary for production.
Scotland has well established trade links with the UK, Europe and the wider
world, which is reflected in the excellent freight transport facilities. The Scottish
road network is both modern and comprehensive. Consequently, traffic
congestion is less than in most other areas of the UK. Also, the UK has a
completely deregulated road haulage industry, offering a large number of high
quality local and international transport providers. Competition for business
between UK hauliers is strong, which ultimately benefits the companies who
utilise their services. Scotland also boasts more than 60 ports, which offer regular
container distribution throughout Europe. One of the main ports is less than an
hour, by road, from the Bankside site being considered by Titox Plc. In addition to
Scotland’s excellent road and sea transport networks, it also benefits from an
outstanding rail infrastructure. The national Eurocentral Rail Freight Terminal
situated between Glasgow and Edinburgh provides Scotland with a rail link to
Europe through the Channel Tunnel. At present, the terminal has the capacity to
distribute more than 400,000 tonnes of freight per year [26]. Again, Titox Plc
would be strategically placed, as the terminal is only one hour away from
Bankside by road.

Scotland can lay claim to a telecommunications system among the most
advanced in Europe. Businesses located here have critical access to high
bandwidth fibre optic routes. This is increasingly important as more and more
local and international business is conducted via this channel.

Astonishingly, Scotland exports more per head of population than Japan or the
US. Exports were worth over £19.3 Billion between 1998-1999 [26]. Furthermore,
export growth for the same year topped 5%. Quite obviously, this level of
performance would not be possible without the excellent transport and
communications infrastructure possessed by Scotland. SDI is confident that this
infrastructure would be better than any Titox Plc has experienced through its
operations worldwide.

Finally, the quality of life in Scotland is very high. For example, the 1999 Healey
and Baker Britain’s Best Working Cities report cited Glasgow as the number one
UK City with respect to transportation, shopping and eateries [26]. Also, Scotland
is world renowned for its breathtaking scenery, historic buildings and cultural and
leisure attractions. Scotland also has a good standard of medical care, provided
free through the National Health Service. Alternatively, private medical care is
available, as is private health insurance. This all adds up to Scotland being an
excellent place in which to live and work
Your Task
As representatives of SDI, your group should present a brief summary
aimed at convincing Titox Plc to invest in Scotland. You may want to
structure your presentation with the following points in mind:

(1) Indicate your major responsibilities as members of SDI.

(2) Using Table 8, indicate the range of chemical companies already operating in
    Scotland.

(3) Outline the wide-ranging benefits Titox Plc will receive by choosing to invest in
    the Scottish site.



Once you have considered all the information, choose a speaker to give
your presentation. The relevant acetates are available for the overhead
projector.
3. Environmentalists

Your team represents the major UK environmental group Greenwatch, having
ongoing concern about pollution attributed to the titanium dioxide industry.
Greenwatch is funded largely by donations from the UK public and, although your
group is concerned with the well being of the planet as a whole, your primary
concern must be for the local environment.

Titox Plc is a UK based company and also one of the leading manufacturers of
TiO2 worldwide. The company has announced plans to increase its world
capacity, in line with predicted long-term growth in market demands. It intends to
build a chloride process plant at a cost of £50m. The new plant will be capable of
producing 50,000 tonnes per annum of rutile TiO2 and will create around 250 new
jobs. This figure could rise significantly with predicted future investment.

Titox Plc has identified two possible sites for the new plant, one in eastern China
and the other on the West Coast of Scotland. A range of criteria has been used
to rate each site against. These include availability of chlorine, the ease of
import/export of bulk materials (feedstock, TiO2 product etc.), energy costs,
road/rail links etc. After careful consideration, Titox Plc initially favoured the
Scottish site but then admitted that the China site was very attractive as it would
offer the company further penetration into the rapidly expanding Asia/Pacific
market. Currently, TiO2 consumption per capita in China is 0.15 Kg/year [20],
significantly lower than the western European figure of 4 Kg/year. In fact, China is
expected to show the greatest increases in TiO2 consumption over the next 10
years worldwide. Also, labour costs would be significantly less with respect to the
China site.

The Scottish site is situated next to the town of Bankside, which was built up
around shipyard docks dating back to the mid-1800's. The shipyard was the
major employer in the area but the shipbuilding industry has been in steady
decline over the past 40 years. The local MP is up for re-election and is very
keen on the Titox Plc investment, as it will help reduce the worryingly high levels
of unemployment in Bankside. Furthermore, past investments in the area have
been transient with various overseas companies creating mainly low value jobs,
which tend to be highly susceptible in times of economic recession. In contrast,
the Titox Plc investment offers high value and, consequently more secure jobs in
the area. However, some of the local residents are voicing concerns about siting
a chemical plant next to their town. Greenwatch share the townspeople's
concerns and feels compelled to lend its voice.

The 1978 EEC directive, and further amendments, aimed at reducing and
monitoring future effluent discharges from the TiO2 industry was broadly
welcomed by Greenwatch. The measures taken were mainly in response to the
environmental inefficiencies of sulfate process technology but are also applicable
to chloride technology. Regulations in Europe and indeed North America have
significantly reduced the environmental burden associated with sulfate plants in
these regions. However, in certain parts of Asia/Pacific and the Rest of the
World, environmental regulations are widely recognised to be much more
manufacturer friendly. Thus, the sulfate process technology still poses problems,
even if not in the UK.

For the sulfate process, the greatest concern is with effluent discharges to water,
containing large quantities of sulfuric acid. Most marine organisms are unable to
tolerate conditions of pH outwith the range 6.7-8.5. The effluent discharged from
sulfate plants has a pH of 1! Consequently, marine life in close proximity to the
effluent outfall is virtually non-existent. In addition, when the effluent enters the
aquatic environment, a fluffy reddish precipitate is formed. Studies [21] have
shown that this precipitated fraction of the effluent causes mechanical blockage
of gills in fish, which can lead to severe respiratory problems. The effluent also
contains small amounts of various heavy metals. Some of these are highly toxic
such as arsenic, mercury, lead and cadmium. Greenwatch suggests that it is
inevitable that such poisons will get into the human food chain.

Your organisation is aware that the Titox Plc investment will utilise chloride
technology, which produces significantly less waste than the sulfate process.
Nonetheless, evidence presented below highlights serious incidents of regulatory
non-compliance by the company resulting in dire environmental consequences
and also compromising the health and safety of local residents.

Firstly, in June 1997 the Deeside chloride process facility owned by Titox Plc was
served with a prohibition notice by the Environment Agency (EA) resulting in
partial closure of the plant [22]. A quantity of toxic titanium tetrachloride liquid
(TiCl4) leaked and subsequently reacted with cooling water giving rise to a dense
white plume consisting of hydrochloric acid mist and fine particles of TiO2. The
police instructed local people to remain in their homes and close all windows and
doors. In addition, a road adjacent to the plant was sealed off for some time. The
EA closure notice remained in force for five weeks until Titox Plc had given
guarantees that restarting the plant presented no further risk to the environment.

Secondly, another major incident occurred at the same Deeside facility in
February 1999 [23]. This time, 8,000 tonnes of effluent, containing 37 tonnes of
concentrated hydrochloric acid escaped from a damaged pipeline onto protected
marshland near to the plant. The company had problems operating pumps and
decided to rely on gravity flow to push effluent through the drainage system. This
led to a build up and eventual escape of effluent through cracks in the top of the
pipeline. Approximately 70,000 m2 of land designated of special scientific interest
was affected by the leak. Clean-up teams spent three days pumping seawater
into the affected marshland in an attempt to dilute the acid to a pH of 2.5 from a
pH of 1. However, the longer-term aim was to return the pH to normal levels of
between 5.5 and 6. It was feared that the leak could have long-term detrimental
effects on around 134 species of birds flocking to the area to feed on wildlife
found in the marshland mud. Titox Plc was fined a total of £150,000 in relation to
the leak. Furthermore, the company was heavily criticised by the local MP for
failing to inform the public, or even the local fire brigade, about the leak for two
days.

Against this background of poor environmental performance by several UK
companies, in 1998 the EA took the controversial step of producing a 'Hall of
Shame' [24] listing its top 10 polluters in the UK. It is a list of companies found
guilty of offences against the environment. Table 9 shows the EA hall of shame
for 1998.

Table 9 EA hall of shame

               Company                         Total fines during 1998
 Titox Plc                                              £382,500
 Tyseley Waste Disposal                                 £95,000
 London Waste                                           £38,500
 Wessex Water                                           £36,500
 Alco Waste Management                                  £30,000
 Anglian Water Services                                 £24,250
 EOM Construction                                       £21,000
 Shell (UK)                                             £20,000
 BNFL                                                   £20,000
 Celtic Energy                                          £18,000
 European Vinyls Corporation                            £18,000

It is noted that Titox Plc is a large chemical manufacturing organisation and not
all of the fines relate to its TiO2 manufacturing facilities. Nevertheless, mishaps
in the production of TiO2 did contribute to Titox Plc’s poor environmental
performance.

The EA's director of operations defended the naming and shaming list saying
'businesses must understand that they have a responsibility to protect the
environment and need to be held to account'. Greenwatch is very much in favour
of the list and feel its actions in Bankside are further vindicated by Titox Plc’s
shameful occupation of top spot in the ‘hall of shame’.
Your Task

As members of the environmental group Greenwatch, your team should present
a brief summary of the group’s position with regard to Titox Plc’s potential
investment in the Scottish site. You may want to structure your presentation with
the following points in mind:

(1) Indicate your major responsibilities as members of Greenwatch.

(2) Titox Plc will criticise Greenwatch’s involvement in Bankside. You must
    defend your organisation and justify its campaign in the town. (Table 9 is
    available on acetate).

(3) Given the economic decline in Bankside, can Greenwatch put forward any
    alternatives to the proposed investment?


Once you have considered all the information, choose a speaker to give
your presentation. The relevant acetates are available for the overhead
projector.
                                SECTION E

                           GROUP A SUMMARY

Having considered the social, economic and environmental issues, should Titox
Plc go ahead with its plans to locate in Bankside?
                                    SECTION F

                            More than just a pigment!

The unit has highlighted the importance of TiO2 in relation to its use as a
pigment. However, the 'success story' of this unique compound doesn't end
there. As a consequence of physical properties already discussed in this unit,
TiO2 has found a number of uses outside of the pigment market.

♦ Photocatalysis

TiO2 (anatase most efficient) is a semiconductor with a bandgap of Eg = 3.2 eV,
and also a high valence bond oxidation potential of around 3.1 eV. Consequently,
TiO2 acts as a photocatalyst when exposed to UV radiation of < 390 nm. Hence,
TiO2 has the potential to oxidise a whole range of organic molecules under these
conditions. A schematic representation of photocatalysis on a semiconductor is
shown in Fig. 18 below.


                       Fig 18 Semiconductor photocatalysis


                                                       A• −


                                                               Reduction
                       hν
                                               −
        ENERGY




                             Conduction Band                   A

                                               E   g


                             Valence Bond      +               D


                                                               Oxidation

                                                        D• −


Examples of applications utilising TiO2's semiconducting photocatalytic
properties are:

(a) Water treatment
(b) Air purification
(c) Solar energy
(a) Water treatment [27]:- Among the more serious pollutants present in the
    public water supply is the female sex hormone oestrogen and also
    xenoestrogens (chemicals that mimic oestrogen). Increasing quantities of
    oestrogen are entering the water supply due to rising use of contraceptive
    pills and hormone replacement therapy (HRT). Studies suggest these
    pollutants are linked to a host of human health problems including
    reproductive failure, breast and testicular cancers, birth defects, etc.
    Conventional water treatments are ineffective against oestrogen and
    xenoestrogen pollution. However, research has shown UV activated TiO2 to
    be 100% effective in destroying the hormone, converting it to harmless CO2
    gas. In addition, the treatment should prove to be effective against many
    xenoestrogens such as agricultural pesticides, polychlorobiphenyls and
    certain detergents. A pilot plant using the TiO2 water treatment technology
    has been set up in Northern Ireland. TiO2 is inert, non-toxic and catalytic, all
    desirable properties with respect to water treatment.

(b) Air purification [28]:- UV activated TiO2 has been shown to be effective in
    destroying airborne micro-organisms including dust mites, mould spores and
    certain pathogens. This is especially applicable to air-conditioned spaces
    such as office buildings, which tend to have problems with traditional filter-
    based air cleaning systems. In fact, air-cleaning filters have been shown to
    increase the risk of contamination due to bacteria concentrating and
    multiplying on them. TiO2 works by photocatalytic production of hydroxyl
    radicals, which disrupt or destroy the micro-organism’s DNA. Air purification
    systems based on the TiO2 technology are already available in the US and
    Japan.

(c) Solar energy [29]:- TiO2 based technology has recently been developed to
    harvest solar energy, culminating in the opening of the world's first titanium
    solar cell factory in Australia. The cell comprises TiO2, an organometallic dye,
    an electrolyte and catalyst sandwiched between two transparent, conductive
    electrodes on glass. When visible light strikes the cell, the dye molecules are
    excited, discharging electrons into the TiO2 conduction band. The electrons
    pass through an external circuit to do work. The catalyst and electrolyte
    interact to reduce the previously oxidised dye, which closes the circuit. Hopes
    are high that the cell may be adapted for use indoors, working off electric
    lighting and incidental daylight, such is the output efficiency of the system.
                       Current state of affairs (Feb 2002)

The interactive unit has illustrated some of the social, economic and
environmental factors that must be considered by TiO2 manufacturers when
deciding the best location for future investments. The ‘Scottish site vs. Chinese
site’ scenario, is loosely based upon the following actual events:

 ♦ At the beginning of 2001, a leading TiO2 company announced plans to select
   a site for a new 50,000 tpa chloride process plant by the end of the year.

 ♦ Three possible locations were mooted for the new plant, expansion of an
   existing plant in either North America or the UK, or a new installation at one
   of twelve possible sites in China.

 ♦ At the time of the announcement (May 2001), the UK site was the leading
   contender with production expected to commence in 2004. However, the
   vice-president of technology at the company was making very positive
   statements about the TiO2 market growth potential in China.

 ♦ No decision has been taken as yet (Feb 2002), although the signs are that
   the company is seriously considering locating in China. In fact, a feasibility
   study ordered by the company CEO into a possible site in China has already
   been carried out. Furthermore, a top executive in the company was quoted
   as saying, ‘It’s not if, it’s when’ in relation to a possible Chinese TiO2 plant.

 ♦ If the TiO2 plant does end up being located in China, the UK will have lost
   out on approximately 300 long-term high value jobs, which the plant would
   provide. Additionally, the building of the plant would create in the region of
   400 construction jobs lasting over a year. Placement of the industrial facility
   in China will have negative effects on the local economy but also, ultimately,
   on the national economy.

    It is in the UK’s longer-term interest to have manufacturing/chemical
    operations plus ancillary research and development facilities located within
    its own shores. A strong modern economy has substantial contributions from
    the service and manufacturing sectors.
                                   Coursework

These interactive teaching units are considered to be an important part of the
second year programme and consequently represent 5% of the total assessment.

The global chemical giant Chemtech Plc is considering the development of a
TiO2 pigment manufacturing business. The company has no experience in this
field and so you have been hired as a respected analyst of the TiO2 industry.
Your task is to prepare a brief development plan for Chemtech Plc (one page of
text, ca 500 words), which would ensure a successful transition into TiO2
manufacture.

It is suggested that you structure your report according to the following points:-

1. Scale of TiO2 demand.
2. Briefly distinguish between the rutile and anatase forms of TiO2 as a pigment.
3. The chemical process that Chemtech Plc should employ (i.e. sulfate or
   chloride).
4. With reference to point 3, which major industries will form Chemtech Plc’s
   customer base?
5. Briefly outline how life cycle assessment (LCA) can be applied to evaluate the
   environmental burden of your selected process.

You must take into account relevant, economic, environmental and social factors
as justification for your development plan. No single answer is correct and a
spectrum of opinion is acceptable, as long as the central science-based issues
are presented.

The report needs to be well structured, neat and easy to read. Typed reports are
not obligatory. Diagrams, chemical equations and tabulated data are
encouraged. Marks will be deducted for poor grammar and spelling.

Essays are to be handed in to your ITU tutor two weeks from operation of the
unit. Late coursework will incur a penalty and coursework received > one week
late will not be marked. Results will be posted on the chemistry department
notice board. Scripts will also be returned.


Acknowledgements

This ITU is based on a teaching exercise originally developed at the University of
Hull. The assistance of Huntsman Tioxide and Scottish Enterprise in assisting
with the development of this exercise is gratefully acknowledged.
Note

Titox Plc is a fictitious company but some of the business scenarios used are
related to those of Huntsman Tioxide. The environmental incidents described in
Section D were associated with facilities operated by Tioxide Europe Limited,
which was at the time part of the ICI Group of companies and is now under the
ownership of the Huntsman Corporation.            Greenwatch is a fictitious
environmental group, Bankside is a fictitious town and ChemTech Plc is a
fictitious company.
References
1. Austpac Resources N.L., Titanium Dioxide,
   (www.austpacresources.com/titanium/default.htm).
2. The Titanium Dioxide Project, Project Improve, Faculty of Science & the
   Environment, University of Hull, 1998.
3. David R. Lide, Handbook of Chemistry and Physics, 81st Ed., 2000-2001, 4-
   32.
4. J. D. Lee, Concise Inorganic Chemistry, 4th Ed., p.686.
5. Greenwood & Earnshaw, Chemistry of the Elements, 1st Ed., 1984, 21,
   p.1112-1113.
6. Emerging Industries, An Investigation of the Market and Economic Factors
   Relevant to Establishing an Australian Titanium Metal Industry,
   (www.isr.gov.au/industry/emerging/ISR_Titanium21mar01.pdf).
7. MRS Bulletin, Electrochemical Method Uses Molten Calcium Chloride to
   Extract Metals Directly From Their Oxides, Technology Advances, Dec 2000,
   p.11-12.
8. K.H. Buchel, H.-H Moretto and P. Woditsh, Industrial Inorganic Chemistry,
   Wiley-VCH, Weinheim, 2000.
9. Encyclopedia.Com, White Lead, 2001,
   (www.encyclopedia.com/printablenew/49965.html).
10. Millenium Chemicals, Titanium Dioxide Crystal Types,
   (www.millenniumchem.com/channels_en.htm).
11. Michael P Diebold, Unconventional Effects of TiO2 on Paint Durability, 2001,
   (http://tipure-europe.asp.dupont.com/english/technical/paint/reactions.htm).
12. Polymer Degradation and Stability, The Role of Titanium Dioxide Pigments in
   the Degradation and Stablisation of Polymers in the Plastics Industry, 29,
   1990, p73-92.
13. Reflectance of Titanium Dioxide Pigment in Various Regions of the Spectrum,
   (www.cse.dl.ac.uk/Groups/CMG/Misia/tio2/TiO2.html).
14. Anne M. Thayer, Titanium Dioxide, Chemical & Engineering News, March 9,
   p.10-13, 1998.
15. James R. Fisher, Titanium Dioxide Pigments Industry in the 1990’s –
   Problems and Profits, Journal of Coatings Technology, 65, 820, p. 67-70,
   1993
16. Donald V. Borst, Titanium Dioxide – An Industry in Transition, Jocca Surface
   Coatings, 80, 2, p.60-65, 1997.
17. R. Thompson, The Modern Inorganic Chemicals Industry, 1977, p. 354-374.
18. E. Reck and M. Richards, Titanium Dioxide – Manufacture, Environment and
   Life Cycle Analysis: The Tioxide Experience, Jocca Surface Coatings, 80, 12,
   1997, p.568-572.
19. EUR-Lex, Community Legislation in Force, Document 378L0176,
   (http://europa.eu.int/eur-lex/en/lif/dat/1978/en/lif/dat/1978/en_378L0176.html).
20. N. Alperowicz, Huntsman Tioxide Studies Sites Worldwide for New TiO2
   Plant, Chemical Week, May 23, 2001.
21. K. J. Lehtinen, Physiological Disturbances in Rainbow Trout Exposed at Two
   Temperatures to Effluents From a Titanium Dioxide Industry, Aquatic
   Toxicology, 5, p.155-166, 1984.
22. News Review, Tioxide Plant Forced to Shut, Chemistry in Britain, 33, 7, July
   1997, p.5.
23. News, Tioxide Leak Threatens Wildlife, The Chemical Engineer, 25 Feb 1999,
   p.3.
24. News Review, The EA’s Hall of Shame, Chemistry in Britain, May 1999, p.11.
25. Huntsman Tioxide – Environmental Performance Report 2000,
   (www.huntsman.com/tioxide/environmentalreport2000/index.htm).
26. Scottish Development International (SDI),
   (www.scottishdevelopmentinternational.com).
27. University of Ulster Fights for Safer Water, 18 Feb 1999,
   (www.ulst.ac.uk/news/releases/1999/112.html).
28. UF Professor: Air Cleaning System Destroys Anthrax, Other Pathogens, Oct
   2001, (www.napa.ufl.edu/2001news/anthrax.htm).
29. Australian Energy News, Titania Solar Tremendous Promise, Issue 20, June
   2001, (www.isr.gov.au/resources/netenergy/aen/aen20/10titania.html).