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					                         Metso Minerals Industries, Inc.
                         240 Arch Street, P.O. Box 15312
                         York, Pennsylvania , USA 17405-7312
                         Phone: + 1 717 843 8671
                         Fax: +1 717 845 5154

                         www.metsominerals.com
                         E-mail: mineralsprocessing.info@metso.com




                                                                                                                                www.metsominerals.com
                                                                     24 ft. x 30 ft.- 14,000 HP Ball Mills


                                                                                                             Metso Ball Mills




Brochure No.2040 06/02
                                                                                                                                                                                          Product Presentation

                                                                                                                      Testing of the Material                                    Automatic operation saves power, grinding media,
                                                                                                                                                                                 and liner wear, while increasing capacity. software
                                                                                                                      Three types of tests are available for mill power de-
                                                                                                                                                                                 can be developed to suit the most complicated cir-
                                                                                                                      terminations.
                                                                                                                                                                                 cuits and complex ores.
                                                                                                                      In most cases one of two bench scale tests is ade-
                                                                                                                                                                                 All equipment adheres to the applicable standards
                                                                                                                      quate. First, a Jar Mill Grindability Test requires a
                                                                                                                                                                                 set by ASTM, NEMA, AGMA, AWS, and ANSI.
                                                                                                                      5 lb. (2 kg) sample and produces a direct measured
                                                                                                                                                                                 Metso mills are equipped with all normally required
                                                                                                                      specific energy (net Hp-hr/t) to grind from the design
                                                                                                                                                                                 safety features. Designs to meet other codes and
                                                                                                                      feed size to the required product size. The second
                                                                                                                                                                                 local or state safety regulations will be quoted on
                                                                                                                      test, a Bond Work Index determination, results in a
                                                                                                                                                                                 request.
                                                                                                                      specific energy value (net Hp-hr/t) from an empirical
                                                                                                                      formula.                                                   Operation
                                                                                                                      If time permits and the user wishes, grinding circuits     Ball mills operate either in open or closed circuit.
                                                                                                                      are set up and continuous tests are run to simulate
                                                                                                                                                                                 Open circuit operation is best utilized when:
                                                                                                                      plant operation. These tests require two or three
                                                                                                                      days for each ore type and approximately 1,000                • Another stage of grinding follows the mill
                                                                                                                      pounds of material for each day of testing. Varia-            • Reduction ratio is small
                                                                                                                      tions in ore hardness or circuit design may require           • Feed material is already fine and one pass
                                                                                                                      larger samples.                                                 through the mill produces the desired results
                                                                                                                                                                                    • Product size control is not critical and oversize
                                                                                                                      Grinding Circuit Design
                                                                                                                                                                                      material can be tolerated in the product
                                                                                                                      Metso process engineers welcome the opportunity
                                                                                                                                                                                 Where size control of the final product is important,
                                                                                                                      to assist you with circuit and circuit control design as
                                                                                                                                                                                 closed circuit grinding is the most efficient method of
                                                                                                                      well as start-up, operation, and optimization of the
                                                                               18 ft. x 22 ft.- 5,500 HP Ball Mills                                                              operation. The production of a higher quality prod-
                                                                                                                      milling plant.
                                                                                                                                                                                 uct at a lower cost justifies the additional capital in-
                                                                                                                      Productive grinding systems are the result of the          vestment.
                                                                                                                      efforts of disciplines ranging from mechanical de-
                                                                                                                                                                                 Common wet grinding flowsheets include:
Grinding of materials in a tumbling mill with the        The feed to a ball mill is prepared by...                    sign and metallurgy of materials to process engi-
presence of metallic balls or other media dates            • Single or multistage crushing and screening              neering and instrument application. Desired grind-            •   Open circuit
back to the late 1800's. Since that time, Metso            • Crushing, screening, and/or rod milling                  ing results are achieved only through careful and             •   Closed circuit with hydro cyclones
Minerals and its predecessor companies, MPSI,              • Primary crushing and autogenous/                         skillful attention to detail.                                 •   Closed circuit with vibrating screens
Sala, Marcy, Hardinge, Kennedy Van Saun                       semiautogenous grinding                                 Our engineers can specify or supply computer con-             •   Two stage variations of the above utilizing two
(KVS), Denver Equipment, Allis Chalmers, Bo-                                                                          trol systems for the sophisticated circuits. The cost             mills in series
liden Allis, and Dominion Engineering, have de-          Normal feed sizes:
                                                           • 80% passing 1/4" (6 mm or finer) for hard ores           of computer hardware decreases almost daily, mak-          Let our engineers review your specifications and
signed and manufactured more than 8,000 grind-                                                                        ing these controls feasible for smaller installations.
ing mills.                                                 • 80% passing 1" (25 mm or finer) for softer ores                                                                     recommend the optimum circuit for your application
                                                             (Larger feed sizes can be tolerated depending
Metso Overflow Ball Mill sizes range from 5 ft. x
8 ft. with 75 HP to 26 ft. x 41 ft. with 20,000 HP.      The length to diameter ratio of cylindrical mills range
Larger ball mills are available with dual pinion or      from 1 to 1 through 3 to 1. When the L/D ratio is 2
ring motor drives. Our mills incorporate many            to 1 or greater, we refer to the mill as a Tube Mill.
of the qualities which have made the Marcy               The two most popular types of ball mills are…
name famous since 1913. These heavy-duty ma-
chines are designed for long life and minimum               Grate or Diaphragm Discharge
                                                            In the discharge end of this mill, a slotted full di-
maintenance.
                                                            ameter or partial diameter grate with discharge
Variations of the standard designs are available            lifter assembly conveys the material to the dis-
to suit any appropriate application. These may              charge trunnion opening. The grate serves to
include but not be limited to: grate discharge,             retain balls, tramp, and coarse material. A gradi-
peripheral discharge, dry grinding, special                 ent created between the feed opening and the
length to diameter ratio, high temperature mill-            discharge slots eases the flow of material.
ing operations, or pebble milling.
                                                            Trunnion Overflow Discharge
                                                            A trunnion overflow mill has an open discharge
Application                                                 end. Material flows through the trunnion as a re-
                                                            sult of the pulp gradient between the feed and
A ball mill grinds ores and other materials to a typi-
                                                            discharge openings. A reverse helix in the dis-
cal product size of 35 mesh or finer.
                                                            charge trunnion liner retains balls in the mill.                                                                                       22 ft. x 36 ft.- 12,500 HP Ball Mill

				
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