MARCY Grinding Mills

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C\-I~MICAL CORPORAT\ON

L35 East 42nd Street New York, N.Y. 10011

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CATAL G 101-B

AN EVOLUTION OF QUALITY PRODUCTS Broad Experience and Years of Development are reflected in the MARCY MILL For more than fifty yea rs th e names MINE AND SMELTER and MARCY have been the symbol of dependable quality ore milling ma chinery, industr ial and mining equipment, and supplies created for your specific needs. During this period thousands of operators have exper ie nced continuous economical and un equalled service throu gh their use . No exact date is reco rded as to when the need first arose for some mechanical means of reducing particles in size, but considering that it has been many years, it is perhaps surprising that grinding is still an "art" and not an "exact science ". The Mine and Smelter Supply Company, through its Manufacturing Divisi on , during these years has continuously accumulated knowledge on grinding applications. It has contributed greatly to the grinding process through the development and improvement of such equipment. Just what is grinding? It is the reduction of lump solid materials to smaller particles by the application of sheari'lg forces , pressure , attrition , impact and abrasion . The primary consideration . then , has been to develop some mechanical means for applying these forces . The modern grinding mill applies power to rotate the mill shell and thus transmits energy to some form of media which , in turn , frac tures individual particles. Just how this can best be done reverts to our history of grinding. In 1914 Mr. Frank E. Marcy established the " Marcy pr inciple of

gri nd ing". This pr inciple is simply stated " rapid change of mill content is necessary for h igh effic iency". This pri nc ip le is incorporated in all Marcy Mills and has been prove n in hundreds of operating installations until it is now gene rall y accepted as a world-w ide axiom . Since the first Marcy installation operators of every class. small as well as large. have shown the ir preference fo r Marcy M ill s. We point with pride to the grea t number of large installations throughou t the world where Marcy Mill s are do ing the gri nd in g. Sma ll m ills prof it from the experience of these la rge operations. Throu gh constant and extensive research . in the field of g rindin g as well as in the field of manufacturin g. Mine & Smelter cont inues to p ioneer. Constantly changing conditions provide a challenge for the future . Meet ing this challenge keeps our company youn g and progressive . This prog ress ive spiri t , with the knowledge gai ned through the years. assures top quality equipment for the users of our mills. Today Mine & Smelter 's modern manu facturing facilities. rigid controls . and close inspection assure excellence in uniformity of our products and satisfactory performance even under the most severe cond it ions. You are urged to study the follow ing pages which present a detailed picture of our facilities and d iscuss the techn ical aspects of grinding. You will find th is data helpful when considering the se lection of the grinding equ ipment.

THE MINE AND SMELTER SUPPLY THE ORE & CHEMICAL CORPORATION

Main Off ice: Denver 16, Colorado, U .S .A .

235 East 42nd Street

3800 Race St.

P.O. Box 9041

New York, N. Y. 10017 122 East 42nd St., New York

El Pa so, Texas Copyright 1958 by The Mine & Smelter Supply Co.

BOTH

MARCY

AND

MASSCO

Sal t Lake Ctty, Utah

ARE REGISTER E D T RADE M ARK S

Printed in U. S.A.

Eight of seve nteen 9 ' x 12' Marcy Rod Mills at Anacondo , Montana

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Marcy Quality and Service

2- 3

Selection of a Grinding Mill

4- 5

From Theory to Practice

6-13

General Construction

14-19

Method of Discharge

20-21

Drives

22-23

Feeders

22-23

Rod Mills

24-29

End Peripheral Discharge Rod Mills

28-29

Center Periphe ral Discharge Rod Mills

28-29

Ball Mills

30-33

Tube Mills

34-35

Pebble Mills

34-35

Special Applications

36-37

Cement Grinding

38-39

Useful Information

40-43

Alphabetical Index

44-45

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MARCY TECHNICA L SERVICE

OVER SO YEARS OF EXPERIENCE It is quite understandable that The Mine & Smelter Supply Company takes pride in the quality of its Marcy Mills because of the tradition established and carried forward in the history of our company. Complementing the human craftsmanship built into these mills, our plants are equipped with modern machines of advanced design which permit accurate manufacturing of each constituent part. Competent supervision encourages close inspection of each mill both as to quality and proper fabrication . Each mill produced is assured of meeting the high requ ired standards. New and higher speed machines have replaced former pieces of equipment to provide up-to-date procedures. The use of high speed cutting and drilling tools has stepped up production , thereby reducing costs and permitting us to add other refinements and pass these savings on to you, the consumer. Each foundry heat is checked metallurgically prior to pouring. All first castings of any new design are carefully examined by the use of an X-ray machine to be certain of uniformity of structure. The X-ray is also used to check welding work, mill heads, and other castings. Each Marcy Mill, regardless of size, is designed to meet the specific grindi ng conditions under which it will be used. The speed of the mill , type of liner, discharge arrangement, size of feeder, size of bearings, mill diameter and length, and other factors are all considered to take care of the size of feed, tonnage, circulating sand load, selection of balls or rods, and the final size of gri nd. All Marcy Mills are built with jigs and templates so that any part may be duplicated. A full set of detailed drawings is made for each mill and its parts. This record is kept up to date during the life of the mill. This assures accurate duplication for the replacement of wearing parts during the future years. Views of our manufacturing plant in Denver are shown on these pages. Other manufacturing plants are located in Canada, England, Australia, Sweden, South Africa, and Finland.

As a part of our service our staff includes experienced engineers, trained in the field of metallurgy, with special emphasis on grinding work. Th is knowl edge, as well as a background gained fro m intimate contact with various operating companies throughout the world, provides a sound basis for consultat ion on your grind ing problems. We take pride in manufacturi ng Marcy Mills for the metallurgical , rock products, cement, process. and chemical indust ries

Partial view of Pattern Shop

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TEST FA CI LITIES As an additional service we offer our testing laboratories to chec k your material for grindability. Since all grind ing problems are different some basis must be established for recommending the size and type of grind ing eq uipment required. Experience plays a great part in t h is phase; however, to establish more direct relationships it is often essential to conduct individua l grindability tests on the spec ific material involved. To do this we have established certain definite procedures of lab-

oratory grinding work to correlate data obtained on any new specific material for compa rison against certain standards. Such standards have been established from conducting simi lar work on mate rial which is actually being ground in Marcy Mil ls throughout the world. The correlation between the resu lts we obtain in our laboratory against these standards, coupled with the broad experience and our company's background, insures the proper selection a nd recommendation of the required grinding equipment.

Portion of Foundry

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3

When selecting a gri nd ing mill there are many factors to be taken into consideration. First let us consider just what constitutes a grinding mill . Essentially it is a revolving, cylindrical shaped machine, the internal volume of which is approxi mately one-half filled with some form of grinding med ia such as steel balls, rods or non-ferrous pebbles. Size of feed to a mill may be considered : coarse ( l" to 2"); medium (1/4" to 3/.!"): or fine•(less than 1/4"). Feed may be classified as hard, average or soft. It may be tough , brittle, spongy, or ductile. It may have a high specific gravity or a low specifi c gravity. The desired product from a mill may range in size from a 4 mesh down to 200 mesh , or into the fine micron sizes. For each of these properties a different mill would be indicated. The Marcy Mill has been designed to carry out specific grinding work requirements with emphasis on economic factors . Consideration has been given to minimizing shut-down time and to provide long, dependable trouble•free operation. Wherever wear takes place renewable parts have been designed to provide maximum life. A Marcy Mill, given proper care, will last indefinitely.

For a number of years ball mill grinding was the only step in size reduction between crushing and subsequent treatment. Subsequently rod mil ls have altered this situation , providing in some instances a more economical means of size reduction in the coarser fractions . The pr incipal f ield of rod mill usage is t he preparation of products in the 4-mesh to 35-mesh range . Under some conditions it may be recommended for grind ing to about 48 mesh. Within these limits a rod mill is often superior to and more efficient than a ball mill . It is frequently used for such size reduction followed by ball milling to proE:luce a finished fine grind. It makes a product un iform in size with only a minimum amount of tramp oversize.

Marcy offers you the following advantages:

The basic principle by which g rinding is done is reduction by line contact between rods extending the full length of the m ill. Such line contact results in selective grind ing carried out on the largest particle sizes. As a result of th is selective grinding work the inherent tendency is to make s ize reduction with the min imum production of extreme fines or slimes.

l . Power requirements and consumption of liners and media are kept at a minimum. 2 . Superior mechanical construction provides continuous low cost operations. 3 . They are available in a large selection of sizes and capacities. 4 . Low pulp level grinding provides an active effective grinding mass within the mill to act on particle size reduction only. There is no wasteful cushioning of grinding action by high pulp levels. 5. For any given capacity, Marcy Low Discharge Level Mills require less floor space, lower transportation costs, and minimum required erection material.

The rod mill has been found advantageous for use as a fine crusher on damp or sticky materials. Under wet grinding conditions this feed characteristic has no drawback for rod mill ing whereas under crushing conditions those characteristics do cause difficulty. Th is asset is of particular importance in the manufacture of sand, brick, or lime where such material is ground and mixed w ith just sufficient water to dampen, but not to produce a pulp. The rod mill has been extensively used for the reduction of coke breeze in the 8-mesh to 20-mesh size range containing about l 0% moisture to be used for sintering ores.

Marcy Mills have beer manufactured in a wide variety of sizes ranging from laboratory units to mills l2 V2' in diameter, w ith any suitable length. Each of these mills, based on the Marcy principle of grinding, provides the most economical grinding apparatus.

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ROD M ILLS

duce a fluid pulp (generally 60 % to 80 % solids) . Dry grinding on the other hand is carried out where moisture is restricted to a very limited amount (generally less than 5 %). Most materials may be ground by use of either method in either ball m ills or rod mi lls. Selection is determined by the condition of feed to the mill and the requirements of the ground product for subsequent treatment. When grinding dry some provision must be made to permit material to flow through the mill. Marcy Mills provide this necessary gradient from the point of feed ing to point of discharge and thereby expedites flow .

BALL MILLS

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Grinding by use of nearly spheri cal shaped gri nd ing med ia is termed ball milling. Strictly speaking, such media are made of steel or iron. When iron contamination is detrimental , procel.3in or natura l non-metallic materials are used and are referred to as pebbles. When ore particles are used as grindi ng media this is known as autogenous grinding. Other shapes of media such as short cylinders, cubes, cones, or irregular shapes have been used for grinding work but today the nearl y true sphe rical shape is predominant and has been found to provide the most economic form . In contrast to rod milling the grindi ng action results from point contact rather than li ne contact. Such point contacts take place between the balls and the shell liners, and between the individual balls themse lves. The material at those points of contact is ground to extremely fine sizes. The present day practice in ball milling is generally to reduce material to 35 mesh or finer . Grinding in a ball mill is not selective as it is in a rod mill and as a result more extreme fines and tramp oversize are produced. Ball mills generally operate at slightly higher speeds than rod mills and thereby impart a cascading action to the gri nd ing media . Ball mills are genera lly recommended not only for single stage fine gri nd ing but also have wide application in regrind work. The Marcy Ball Mill with its low pulp level is especially adapted to single stage grinding as evidenced by hundreds of installations throughout the world. There are many applications in specialized industrial work for either continuous or batch grinding.

WET AND DRY CRINDINC

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Wet grinding may be considered as the grindi ng of material in the presence of water or other liquids in sufficient quantity to pro-

ADVANTAGES OF WET GRINDING l . No dust problem. 2 . Damp and sticky feed may be treated. 3. Low power consumption. 4 . Simplified material handling. 5 . Higher mill capac ity. 6 . Size classification is simplified. ADVANTAGES OF DRY GRINDING l. Lower steel consumpti.on . 2 . Elimination of dryi ng or filtering f inished product.

FINENESS OF GRIND The fineness to which material must be ground is determined by the individual material and the subsequent treatment of that ground material. Where actual physical separation of constituent partic les is to be rea lized grinding must be carr ied to the fineness where the individual components are separated. Some materials are li berated in coarse sizes whereas others are not liberated until extremely fine sizes are reached. Occasionally a sufficient amount of valuable particles are liberated in coarser sizes to justify separate treatment at that grind. Th is treatment is usually fol lowed by regrind ing for further liberation. Where chemica l treatment is involved , the reaction between a solid and a liquid, or a solid and a gas. will generally proceed more rapid ly as the particle sizes are reduced. The point of most rapid and economica l change would determine the fineness of grind required. Laboratory examinations and grinding tests on specific materials should be conducted to determine not only the fineness of grind required , but also to indicate the size of commercial equipment to handle any specific problem.

5

A NOTE ABOUT M I L L SHAPE

Marcy mills are essentially cylindrical ir""" shape and this design has been selected for very definite reasons.

The following few pages are devoted to the subject "From Theory to Practice" taking you step by step through some of the variables encountered in grinding and how each of these affect your operations. As previously pointed out, grinding must still be considered an art and not an exact science. As a result many theories have been expounded on the numerous variables which enter into grinding work. Should it be possible to reduce all of these variables to a simple mathematical formula the selection of a grinding mill would, of course, be simple. Many approaches to this have been made but to date a fool-proof formula, both mathematically and practically applicable, has not been devised. W e must, therefore, take each variable into consideration on its own merits and then correlate such ideas into a single selection. To do this a broad experience and understanding of the complete subject of grinding is essential. This is a part of the problem of your engineers and our own consulting staff. On page 5 two general points have been discussed briefly — wet or dry grinding, and fineness of grind. T w o main categories of grinding equipment, namely rod mills and ball mills, have also been mentioned. Whether grinding is to be performed wet or dry, or in a ball mill or rod m i l l , a choice must be made between open or closed circuit. Other factors which require thought are mill size, speed of mill rotation, moisture content, retention time, circulating load, type and sizes of grinding media, mill pulp level, mill shape, power, and relation between diameter and length. These all influence operating results and are evaluated and incorporated in the selection and design of the Marcy M i l l .

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M i l l capacity is a function of the mill vol — ume and the load of grinding media. Therefore to obtain a mill of greatest capacity for any given space, pure logic dictates a mill having the greatest volume. W h i l e a square— section would provide the greatest volume, smooth continuity of operation and uniformity of media action must also be considered and thus a true circle is the only practical answer.— Should the diameter vary from one end to another there is but one thing which occurs— reduced volume, or in other words, reduced capacity. —

The cylinder simplifies mill construction, resulting in a m i n i m u m amount of maintenance and reflecting in less downtime. Powerwise, cylindrical mills provide the most economical piece of equipment for grinding work. Floor space for any mill is proportional to the diameter of the mill and its length. Therefore, floor space is kept at a m i n i m u m . A m i l l . ~ keeping uniform diameter throughout its full length obtains maximum volume for a given floor space.

LENGTH OF M I L L The relationship of mill diameter to length, is of considerable importance. Rod mills should have a length greater than the diameter to avoid entanglement' of rods. The construction of ball m'ills is different in that the diameter, may be larger, equal to, or smaller than the length. The selection of mill length is dependent upon the size of feed, size of product a n d ' type of grinding circuit selected. Considerations given a short mill are the reduced floor space, shorter retention time producing less fines in the discharge product, and the possi-' bility of producing a slight amount of tramp oversize particles. Corresponding conditions to be expected f r o m a longer mill are greater floor space requirements, higher capacity' (closely proportional to mill length), greater retention time thereby producing a finer mill discharge product and a greater amount of extreme fines, less tramp oversize in the product." Since most mill variables act as a function of the mill length, this consideration is relatively simple. On pages 10 and 1 1 considerable discussion is provided on the subject of m i l l " diameter.

OPEN AND CLOSED CI RCU ITS SINGLE A N D TWO-STAGE GRINDING

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Advantages of ope n circuit grinding: 1. Simplicity of m ill layout. May be used where classifying is not practical . 3. May be used where contro l o f product size is not important. 4 . The use of rod m i l ls will produce an ideal fine feed for ball mills. 5 . May be used where classi f ier dilutuion would be objectionable. 2.

The method of operating a grindi ng mill may be classified into two methods. open circuit or closed circuit. In open circuit grinding feed enters one end of the mi II at a predetermined rate so as to make the desired finished product during a single pass through that mill. In other words there is no size classi f ication made on the discharge product. One important application is on ores containing damp and clay-like material which causes difficulty in fine crushing. This problem is generally solved by wet grinding in a rod mill or in this case it may be called wet fine crushing. In closed circuit grinding the feed enters one end of the mill and is discharged from the other end into some type of classifier . This class ifier is to limit maximum particle size removed from the mill circuit. The oversize material is returned to the grinding mill for additional size reduction. Such material returhed to the mill is defined as the circulating load. Classifying equipment may consist of vibrating screens on coarse separations for wet or dry grinding. For wet grinding in the finer size ranges wet classifiers and/or cyclones are employed, generally to make a size separation from 20 mesh down to 325 mesh. Under dry grinding conditions air classifiers are used to make the size classification . Single stage grinding may be defined as grinding original feed to finished size in a single mill . It may o;:>erate in either open circuit or closed circuit. Two stage or multiple stage grinding may be defined as grinding in two or more u ni t s with each unit making a step in size reduction . Each mill may operat e either as open circuit or closed c i rcuit.

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2. 3. 4.

product size. Mill capacity is greatly increased . Power requirements per ton of f i nished material are lower. Less overgrinding or production of ext rem e f in es.

Advantages of single stage grinding: 1.

Less equipment to purchase. install and mai ntai n . 2 . Less floor space requirements.

Advantages of two-stage grinding: 1. Less overgrinding. 2. 3. 4.

Provides a simp l ified fine crush i ng pla n t and grinding section . May be used to increase capac i ty of exist in g single sta ge operation . Provides an opportunity for recovery of desirable material between stages of size reduct ion .

CIRCULATING LOAD Generally speaking circulating loads for rod mi ll operation will be less than 200 %. In most cases it will more closely approach 100% to 120 %. In ball mill operations the ci rc u lat in g load will vary between 300 % and 1000 % depen ding upon the grind required and t ype of m aterial . As an average it will app roach 3 50 % .

F • FEED

D : DISCHARGE F-

O =OVERSIZE RETURN SANDS

PRIMARY MILL

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D-

C =CLASSIFIER FINISHED PRODUCT

OPEN CIRCUIT OR SINGLE STAGE

F

Advantages of closed circuit grinding: 1. Prov1des a close control of fin ished

Two sTAGE : PRIMARY OPEN CIRCUIT SECONDARY CLOSED CIRCUIT

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6

3

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5 6 7

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8

9

10 II

1/2" To 48 Mesh

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The above dimensions are approximate and for preliminary use only. Right hand mills are shown . For left hand mills put drive on opposite side . Drive may a lso be located at feed end . but clearance of scoop must be considered.

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Essentially tube mills and pebble mills may be considered as ball mills, the basic difference being that the ratio of length to diameter is greater. Usually the shell length is between 2 and 5 times the diameter. These mills are primarily used to grind various materials to 100 mesh and finer . The Marcy Tube Mill uses iron or steel balls as the grinding media , and ~ers of various metals and alloys. Where iron contamination is detrimental such as in the case of grinding Feldspar for porcelain, Corundum, talc , certain clays, chemicals and glass sand, a pebble mill is indicated. In such cases the mill is then lined with silex, granite blocks or porcelain, held in place by special cements. The general construction of a pebble mill is much lighter since the load is much reduced. The horsepower requirement, size for size, is lower than for a tube mill. Either type of mill may be operated wet or dry . In wet grinding the tube mill operates in closed circuit with a mechanical classifier. In dry grinding an air separator is used on the finer separations to classify and return the oversize to the mill. A great number of these mills will operate in open circuit on single pass grinding. Feed size is usually limited to -Ys" in pebble mill grinding and may be increased slightly to about lh" in tube mill grinding. One of the main applications is in the regrinding of flotation concentrates prior to further treatment. The use of grates in these long mills for the pur~se of increasing the migration of finished product becoming more and more common . Tests conducted at a Canadian plant have shown 30% to 40% tonnage increase when using grates as compared to an overflow type. L1ttle or no increase in power or pebble consumption was noticed. Tests run by Sylvanite Gold Mines in Canada have shown 13% to 25% more -200 mesh produced on a power basis in a Marcy Grate Tube Mill than produced in an overflow tube mill. On the basis of mill volume the grate mill shows 10% to 29% more capacity per cubic foot than overflow tube mills. These Marcy Mills are available with a wide variety of feeders and types of drives. These are described in more detail on pages 22 and 23. The general construction of these mills is similar to that outlined in the section pertaining to Marcy Mill construction. For special applications these mills can be designed for batch grinding work rather than the normal continuous grind.

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Marcy Tube Mill installed at the Climax Molybdenum Corporation , Climax , Colorado.

Pebble Mills

The table below lists a few sizes of Marcy Grate Discharge Ball-Tube mills with thei r typical capacity based on wet grinding 8 mesh fee d to 100 mesh in closed circuit with a suita b le classifier. For dry grinding reduce capacity approximately 30 % to 50 %.

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Size of Mill (Feet )

Approx. Weight Pounds

12 16 20

32,500 38,500 44 ,500

10.3 13 .7 17 .2

115 153

44,300 51 .700 59 , 100

4 4 4

X

X X

45% Ball Capocity Charge Tons Per 24 Hours Tons

HP To Ru n

HF Motor

RPM of Mi ll

192

90 120 150

100 150 150

30 30 30

17 .2 22.3 27.3

242 312 380

170 225 280

200 250 300

27 27 27

18.7 26 .0 33 .6 41.2

329 460 590 723

215 296 380 46 5

250 300 400 500

24 24 24 24

5

X

]4

5

X

5

X

18 22

6

X

10

6

X

]4

6 6

X

18 22

71 ,000 86 ,200 101 ,400 116,600

7 7

X X

12 16

100,300 115,500

29 .8 40 .0

600 800

360 480

400 500

22 .5 22 .5

8

X

10

3 1. 8

8

X

]4

8

X

20

127 ,800 143 ,00 0 165 ,800

725 1000 1450

410 570 810

450 6 00 900

21 21 21

X

44.4

63 .4

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PEBBLE MILL MEDIA AND LINING The lining for pebble mills may be either standard types of metallic lining, or for the prevent ion of iron contamination non-metallic material s can be used . Such non -metall ic lining material is Ja sper. Silex, or other tough , hard natural stone. A recent development is the Coors h igh-strength Alum ina ceramic m ill lining brick. This has the followin g character istics : Tensile strength-18 ,000 to 20 ,000 PSI Compressive stre ngth-200.000 to 225 .000 PSI Flexural strength--45,000 to 46 ,000 PSI Modulus of elasticity-31 ,900 .000 Hardness, Moh 's Scale-9 Specific Gravity-3.4 It is avai lable in 1 Y2" thick plain brick. 1 Y2" thi ck with lifter bar integral, and 2" thick plain . Grind ing media may be either pebbles, rock , or the new developme nt known as Coors Alumina Ceramic hi gh den sity grind ing med ia. The media charged to a pebble mill should be betwee n 50 % to 55% of the mill volume. The desirable characteristics of such grind ing media are that they should be tou gh, hard . heavy , and resistant to any chem ical action , with the material to be ground . Pebbl e consumption generally averages 2 # per ton with a wide variation of between Y2# to 9 # per ton . Relat ively smooth lining results in less media wear , as does maintaining a high circu lating load . COMMERCIAL PEBBLES

The table below lists a few sizes of Marcy Pebble Mills with their typical capacity based on regrinding 8 mesh feed to 100 mesh in closed circu it with a suitable classifier, using pebbles ; wet grinding. For dry gri nd reduce capacity approximately 30% to 50 %.

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Size of Mill (Feet)

Approx. Weight Pounds

12 16 20

24,000 28 ,000 32 ,000

3 .7 5.0 6.3

14 18 22

40 ,500 46 ,000 51 ,500

10 14 18 22

4 4 4

X

5

X

5 5

X

6 6 6 6

X

X

X

X

X X X

7 7

X

8 8 8

X

X

X X

Pebble Capocity Charge Tons Per Tons 24 Hours

HP To Run

HP Motor

RPM of Mill

29 38 40

23 30 38

30 40 50

32 32 32

6 .8 8 .8 10.8

54 64 75

39 50 61

50 60 75

28 28 28

40,000 47 ,500 55,800 63 ,000

7.1 9 .6 12.8 15. 1

63 80 96 118

43 61 79 97

60 75 100 125

24 24 24 24

12 16

48,800 54 ,000

11.6 15 .4

94 120

72 100

100 125

20 20

10 14 20

67,300 72,300 78,000

12.6 17.6 25 . 1

112 153 220

83 117 165

100 150 200

18 18 18

Pebble No.

Size (Inches ) Minimum Max imum

1 1 -11/4 ]3,4

0 1 2 3 4

2% 3%-3 %

5 6 7

33_4-5 4 3/.t-5 Y2

3 Y2-4 Y2

1V2 13_4- 2 2 Ys-2 Y2 31/4 3 3/.t-4 Y2 4 -5 Y2 6 -63_4 7 -7Va

ALUMINA CERAMIC HIGH DENSITY GRINDING MEDIA Size Diameter (Inches)

No. of Pieces Per Cubic Foot

1 11/4

1960 1000 580 360 245 120

1Y2 ]3_4

2 2 Y2

Th e above media weighs approximately 135 # per cubic foot . It is shipped in 100 # sacks . It is preground to remove the slightly rough "as fired " surface .

35 l

RECLAIMING METALS The Marcy Grate Discharge Ball Mill in conjunction w ith the W il fley Concentrating table finds wide application in foundry practice. This equipment is used for recovering metals from ashes, slag, clinker, furnace linings and cinders. In brass foundry applications this combination has often produced results in recovering 99Y2% of the metal content in the foundry waste. The Marcy method is not complex nor expensive--only limited space is required and operation requires no specially tra ined personnel.

COKE GRINDING With the advent of finer grinding of iron ores. improvements in beneficiating such ores, and changes in pyrometallurgical treatment of ores comes the requirement of reducing coke to finer sizes. Marcy has in essence again pioneered in th is application and developed ·the EPD Rod Mill to solve this problem .

DRY GRINDING Marcy Open End , End Periphe,al Discharge , CPD Rod Mills and Grate Disc harge Ball Mills are partic ularly efficient fo r dry grinding. Such ma terials as limestone, cement clinker, gravel , phosphates, clays, gypsum, oil shale , terra cotta mixtures, coal and coke are economically reduced in size through their use. Many such applications indicate the use of open circuit coarse grinding and in such cases the product will contain only a small amount of oversize material. Generally such operations are to the 4-20 mesh product size and work is done by the Marcy Rod Mill. As product size becomes finer closed circuit grinding is indicated. Where the finish grind is to

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Generally, no preliminary crushing need be considered since the Marcy Mill will handle material up to 3 Y2" in size. This feed can be shoveled by hand into the mill feeder or in larger plants automatic feeding can be used . Water is added with the feed . The pounding action of the balls within the mill liberates the metallics from waste. The coarse and fine metallics are not ground or appreciably reduced in size but are clean and d ischarge thru the special Marcy Grate slots out of the mill and over an integral trommel. The trommel screen removes the coarse metallics and the fines pass thru to the Wilfley Table. Since the waste material is ground to a slime these fines quickly pass off the table to waste. The heavier metallics separate out on the table and move forward to the concentrate zone to be collected. Such concentrates are about 98% pure suitable for direct melting in a crucible. Operation is continuous. One man may operate such a plant.

Coke will contain a variable amount of moisture which critically affects the behavior in transporting and actual size reduction within the rod mill. Moisture content approximating 12% is most common . Below this the problems are simplified . Above 12%, moisture can nearly stop a II grinding action-Marcy experience will guide your engineers in selecting the proper mill for your specific conditions.

35 mesh or coarser, screens can be used to advantage . A typical circuit of this type is shown to the right on page 37. As grinding becomes finer Marcy Ball Mills are required and closed circuit operation is generally recommended. Air separators do the sizing work as shown in a typ ical circuit on the left of page 37. In dry grinding work, principally fine grinding, size reduction is accomplished predominately by attrition rather than impact. This is accomplished by operating such mills at lower peripheral speeds than under wet grinding applications. Power consumption for any given size mill then is lower al though KWH/ton of material treated will be higher than wet grinding. This reaction is a result of a differently acting "bed of pulp" and lack of grinding media "coating". Due to a common "swelling action " of dry material being ground, the grinding media level is often reduced to approximately 40-42 % of mill volume. Dry grinding offers less steel consumption than its equivalent wet grinding counterpart.

Sizes and Capacities Size of Mill

Diameter I.D. Shell

32 43 54 64 Y2

24" 36" 52" 50"

38" 48" 60" 76"

=-

Tons / Hour CApprox.)

L.ength Nominal

0 ___

1-1.5 2- 2.5 4-5 10- 12

-------

........

~

M otor H.P.

M i ll Weight

Ball Charge

7 Y2 20 40 75

6300# 14750# 24800 # 47000#

1200# 3000# 5000 # 12000#

* Wilfley Tables Required

190n-o • otno 1 ~ .. , •• ,.,.,.._ l oll - • , ., ..

/

One Two Four Eight

n

Plan Vitw of Metal Re cla iming Circu it

* N o. 6 or No. 11 -D. Described in Bulletin 64 -A2 .

COKE GRINDING IN MARCY END PERIPHERAL DISCHARGE ROD MILLS

-

M ill Size Diameter

Mill Speed

Grinding Rod. Length

5'-0" 5'-6" 6'-0" 6'- 6"

27

12'-0" 12'-0" 12'-0" 12'-0 " 12'-0" 12'-0" 12'-0" 12'-0" 15'-0"

7'-0" 7'-6" 8'-6" ,.9-, 6 ,.9-,6

RPM

25 Y2 RPM 24 22 20 1B Y2 16 Y2 16 16

RPM RPM RPM RPM RPM RPM RPM

Motor H .P. 125 150 175 200 250 300 350 500 600

Capacity Tons Per Hour-Open Circuit Approx. 12 % Moisture Feed 1" Feed 6 Mesh Product 1 V.. " Feed 8 M esh Product

9 11 V2 13 Y2 16 19 22 28 39 49

8 1o Y2 12 Y2 15 17 Y2 20 26 36 46

ORE BIN

Closed Circuit W ith Me ch anical Classifyi ng Syste m

I_

....

A Cklndler

D Prtuuu Gouo•

8

E

Col llctOf

PrtiiUtl Control Vo iYt

C Rotorr Fudlr

N Nuh Vo lvt

0

P

Ove,. lu Re!ur l'l

Flnls htd Product

Closed Circ uit With Air Se parator Syste m

37

The Marcy principle of grinding is nearly universally adapted in the cement industry. Grate Discharge Ball Mills are the rule rather than the exception . Rod Mills for raw and finish grinding begin to enter the picture. Larger and larger diameter mills become common . Lengths tend to shorten . These are in reality Marcy Firsts-Marcy Pioneering-The Marcy principles developed in the ore milling industry applied to the cement industry. This experience plus the years of manufacturing know how unquestionabl y qualify Marcy for the Cement Industry.

RAW GRINDING This phase of grinding may be either the wet or dry process, the end product going to a kiln . Material ground consists of limestone, cement rock , marl or marine shells along with secondary materials usually shale or clay. A typical raw mix consists of 75-85% limestone , 12-25% shale, the balance consisting of silica or quartzite and iron oxide. Exact proportioning is dependent upon their chemical properties before and after calcining to cement clinker. For good kiln practice the grind required is 88-92%-200 mesh for standard cement, 99% - 200 mesh for high early. Uniform kiln feed size helps reduce ten dency to form kiln rings.

WET VS. DRY Wet grinding is generally more efficient and permits a balanced feed direct to the grinding mill since a thorough mixing takes place during comminution . Since dust is not prevalent this hazard is eliminated and a cleaner plant results. More efficient classification is possible although due to high d ilutions thickeners are required to provide about 65% solids for kiln feed . Where low cost fuel is available, the extra heat required during calcining, to drive off water. is actually less costly than resorting to less efficient dry grinding. Improvements in air separators and more efficient dust collecting systems have minimized some of these problems to a point where present day costs

38

HOME OF MARCY MILLS. Aerial view of manufactur· ing facilities, Denver, Colorado.

become closely parallel . Only close economic study can determine which process should be used .

CLINKER GRINDING Cl inker, the discharge product from the kiln , is partially cooled and broken or crushed to about 3/.J''- 1" as feed to finish mills. Fineness of grind is dependent upon the type of cement to be produced. Since fineness of grind falls below standard screen size accuracy, fineness of grind is determined by use of a " Wagner" Turbidometer. Desired grind then is expressed for example as 1750 Wagner. Another determination is by a ir permeability surface area method termed " Blaine". For close approximation and comparison the two have the following arbitrary relation Wagner Blaine -:- 1.75 . An indi cation of Wagner in terms of mesh sizes is provided in the followi ng table :

=

Wagner 1000 1200 1400 1600 1800 2000 2300

% - 200 Mesh 78-80 82-85 87-89 95-98 98-99.8 99-99.8 100

%-325 Mesh 62-64 70-72 76-80 89-91 94-96 97-98 .5 99-99 .8

GENERAL INFORMATION Power Raw Grinding

Wet Closed Circuit ....... . 10 - 19 HP Hrs/Ton 7 - 14 KWH /Ton Wet Open Circui t ... ....... 12- 21 HP Hrs/Ton 9- 16 KWH/Ton Dry Closed CircuiL ... .... . 13 - 21 HP Hrs/Ton 10 - 16 KWH/Ton Dry Open Circuit ............ 17- 25 HP Hrs/Ton 13 - 19 KWH/Ton Power Clinker Grinding Closed Circuit ·- -····------- --6.4 - 8 HP Hrs/BB L 4 .8 - 6 KWH/BBL Material Handled 585 - 620 # raw material yields 1 BBL cement (376#) or average ratio 1.66 : 1.

HOME OF CEMENT. Aerial view of typical cement plant. This plant now houses three 9 Y:z' x 25', an 8 Y:z ' x 7 ', three 8 'V2 ' x 6' and one 9'V2' x 9' Marcy Crate Disc harge Ball Mills and one 9 'V2' x 12' Marcy Open End Rod Mill.

Installation showing one of (3) 9 Y:z ' x 25' Marcy Ball Mills at West Coast Cement Plant.

RAW CRINDINC-%" FEED (AVERAGE MATERIAL) Mill Size 6 X 12 7 X 12 8 X 12 9 X 1S 10 X 16 11 X 16 12 X 16 77 7 X 10 88 8 X 11 99 9 X 12 10 X 10 10 X 1S II X 14 12 X 1S

Motor HP Wet Dry 200 1SO 2SO 200 3 SO 300 600 4SO 700 600 700 900 1000 800 200 200 300 300 300 300 400 400 6 00 soo 700 700 700 800 12SO 1000 12SO 12SO ISO O 1SOO

Mill RPM Wet Dry 23 .0 17 .S 20.0 1S .O 17 .S 13.2 1S.S 11.8 14 .0 1O.S 12.7 9 .6 11 .7 8 .8 21.8 20 .8 21.8 20 .8 21.0 19.S 21.0 19.S 20 .0 18.4 20 .0 18.4 17 .9 17.3 17 .9 17.3 17.2 16.6 16.0 1S.9

Tons- Rod Charge Wet Dry 29 .7 27 .7 40 .0 38 .3 S3 .0 49.4 83 .7 78.0 114 106 124 133 148 ISS -------····

----·-

····-·

-----· ·-----

--····

----- -----------

-----·

----- --- ------ ·· ------

---- ·-

---------- ---- -··--··

Tons- Ball Charge Wet Dry

·····-

--------------- -----------

------

----- ----·· ---- ------ -

----------------

17.4 16 .8 25.0 24 .0 2S.4 24 .6 3S .O 33 .8 36.0 34 .8 48 .0 46 .4 53.3 Sl.S 80 .0 77 .2 83 .8 81.0 107 103 PRODUCTS ABOVE

I

I

Capacity - Tons Per 24 Hours Open Circuit Closed !' Closed Wet Dry Wet Dry Wet Dry 790 440 900 soo ----·· -----1100 12SO 71S 625 ---------- 1420 900 78S ...... 1620 ------ ROD 2260 1290 2580 1470 ---- ------- MILLS 4000 1970 3SOO 1730 -----· --··· · 4000 2000 ...... 4SOO 2300 -----· sooo 2700 4400 2380 ---- ---·-·· 81S 730 263 sao 52S 36S 1040 375 1160 83S 7SO S20 89 S 1100 810 122 0 sso 40S 1680 1240 1510 1100 7SS sss 2240 1S30 2000 1380 1000 690 BALL 91S MILLS 2960 2040 2660 1830 1330 2700 1960 13SO 980 3000 2180 447S 3275 4000 2940 2000 1470 4380 3200 4900 3S40 2200 1600 6100 48SO S47S 437S 2720 2200 1 3 -S % + 10M 3-S % + 28M 40 %- 200M 46% - 200M 90%- 200M

I

I

I

I

I

I

CLINKER CRINDINC (AVERAGE MATERIAL)

-

-

Mill Size 6 X 12 7 X 12 8 X 12 9 X 1S 10 X 16 11 X 16 12 X 16 77

7

X

20

88 8

X

99 9 10 10 11 11 12 12

24

Motor HP 1SO 200 300 4SO 600 700 800

Mill RPM 17.S 1S.O 13.2 11. 8 1O.S 9 .6 8 .8

200

20.8 20 .8 19.S 19.S 18.4 18.4 17 .3 17.3 16.6 16.6 1S.9 1S.9

soo

3 00 800

soo

12SO 2S 70 0 X 10 1SOO X 2S 1000 X 12 2SOO X 30 1SOO X 13 3000 X 36 * Bbls / 24 Hours X

I

Rod Product Open* Ball Feed Cha rge Charge Size Size Circuit Tons Tons Capacity 1" 27 .7 10 Mesh 2S60 -----1" 38 .3 10M 3660 ----- 1" 49.4 10M 4S70 ---- -1" 10M 78 .0 7SOO ----- 1" 106 10M 10000 ----- 1" 124 10M 11700 -----1" 148 10M 13900 -----BELOW-CLOSED CIRCUIT CRIN DINC CAPACITY 16 .8 20 Mesh 1750 870 -----· 48 .0 20M 1750 2320 -- ···· ...... 2 4 .6 2 0M 1750 1410 ...... 7 3 .8 20M 1750 3930 34 .8 2 0M 1750 2S80 -----· 96 .S 20M 1750 66SO ····-S1.S 20M 1750 38SO ······ 129 20M 1750 89SO -----70 20M 1750 S360 ---··174 ...... 20M 17 50 12450 ...... 90 20M 175 0 8200 24 8 20M 1750 21000 ······ Product S1ze. 10 Mesh - 32% 200M, 20 1750 - Wagner

Feed Size 1" 1" 1" 1" 1" 1" I"

3,4" 3,4" 3,4" 3,4" 3,4 " 3,4" 3,4 " 3,4 " 3,4" 3/.j .. 3,4" 3,4"

Mesh -

Product Size 20 Mesh 2 0M 20M 20M 20M 20M 20M

Closed* Circuit Capacity 1840 2640 3300 S400 72SO 8400 10000

17SO sso 1750 1460 1750 87S 17SO 2440 17SO 1SSO 17SO 4000 17SO 2280 1750 S300 17SO 3240 17SO 7SSO 17SO 46SO 17SO 12000 40 % 200M

ROD

MILLS

I

BALL MILLS

I

39

MARCY 1/ 64 l / 32 3/64 l / 16 5 / 64 3 / 32 7 / 64 I/ 8 9 / 64 5 / 32 11 / 64 3/ 16 13/ 64 7/ 32 15/ 64 1/ 4

I InfOrmation

.015625 .03125 .046875 .0625 .078125 .0937 5 .109375 .125 .140625 . 15625 . 171875 .1875 .203 125 .21875 .234375 .25

DECI MAL EQUI VALENTS OF ONE INCH 17 / 64 .265625 33/ 64 .515625 9 / 32 .28125 17 / 32 .531 25 19/ 64 .29687 5 35 / 64 .546875 5 / 16 .3125 9/ 16 .5625 21 / 64 .328125 37 / 64 .578125 II / 32 .34375 19/ 32 .59375 23/ 64 .359371 39/ 64 .609375 3/ 8 .375 5/ 8 .625 25 / 64 .390625 41 / 64 .640625 13 / 32 .40625 21 / 32 .65625 27/ 64 .421875 43/ 64 .671875 7/ 16 .4375 11 / 16 .6875 29/ 64 .453125 45/ 64 .703125 15/ 32 .46875 23/ 32 .71875 31 / 64 .484375 47 / 64 .734375 1/2 .5 3/ 4 .75

49/ 64 25 / 32 51 / 6 4 13/ 16 53/ 6 4 27/ 32 55/ 64 7/ 8 57/ 64 29/ 32 59/ 64 15/ 16 61 / 64 31 / 32 63/ 64 I

.765625 .78125 .7968 75 .8125 .828125 .84375 .859375 .875 .890625 .90625 .921875 .9375 .953125 .96875 .984375 1.

CONVERSION TABLES DIRECT FACTOR

___..

CONVERT

REVERSE FACTOR

DIRECT FACTOR

30.48 .3048 2.54 .0254 25400 25.4 25400000 1000 1.6093 .9144

length Feet to Centimeters Feet to Meters Inches to Centimeters Inches to Meters Inches to Microns Inches to Millimeters Inches to Millimicrons Inches to Mils Miles to Kilometers Yards to Meters

.03281 3.2808 .3937 39.3701 .00003937 .03937 .00000003937 .001 .6214 1.0936

.0000303 .0226 .001818 1.356 746

Power Foot Lbs./min. to H.P. Foot Lbs./min . to Watts Foot Lbs./ sec. to H.P. Foot Lbs./ sec. to Watts Horse Power to Watts

33000 44.25 550 .7375 .001341

28326.14 1728 28.32614 .0283261 .0370370 28.3173 16.387 .016387 .0000214 .0043290 .764526 3.7851 1.000027

Volume Cu. Ft. to Cu. Centimeters Cu . Ft. to Cu. Inches Cu . Ft. to Cu. Decimeters Cu . Ft. to Cu . Meters Cu. Ft. to Cu. Yards Cu. Ft. to Liters Cu. Ft. to Cu. Decimeters Cu. In to Cu . Meters Cu. ln. to Cu. Yards Cu. ln. to Gallons Cu. Yds. to Cu. Meters Gallons to Liters Liters to Cu. Decimeters

.0000353 .0005787 .035314 35.314 27 .035314 .061024 61.0239 46656 231 1.308044 .2642 .999973

1016.05 28.3495 453.6 .4536 .0004461 .0005 907 .18

Weight (Avoirdupois) Long Tons to Kilograms Ounces to Grams Pounds to Grams Pounds to Kilograms Pounds to Long Tons Pounds to Tons Tons to Kilograms

.0009842 .035274 .0022046 2.2046 2240 2000 .0011023

+---

40.46 43560 247.1 .0015625 160 4840 1076.391 .0001 .1 55 .0001 100 144 .09290304 .00000003587 92903.04 .003673094 .111111111 11 .0064516 645.16 1000000 .0000255 .0007716 .386108 1000000 1.1959899 30.25

Area Acres to Ares Acres to Sq. Ft. Acres to Sq. Kil ometers Acres to Sq. Miles Acres to Sq. Rods Acres to Sq. Yards Ares to Sq. Feet Ares to Sq. Kilometers Sq. Centimeters to Sq. ln. Sq. Centimeters to Sq. Meters Sq. Centimeters to Sq. Millimeters Sq. Feet to Sq. Inches Sq . Feet to Sq. Meters Sq. Feet to Sq. Miles Sq. Feet to Sq. Millimeters Sq. Feet to Sq. Rods Sq. Feet to Sq. Yds. Sq. Inches to Sq. Meters Sq. Inches to Sq. ~illimeters Sq. Inches to Sq. Mils Sq. Inches to Sq. Rods Sq. lnct1es to Sq. Yards Sq. Kilometers to Sq. Miles Sq. Meters to Sq. Millimeters Sq. Meters to Sq. Yards Sq. Rods to Sq. Yards

.0247157 .000022956 .0040469 640 .006250 .0002066 .0009290304 10000 6.4516 10000 .01 .006944444 10.76391 27878400 .000010764 272 .25 9 1550.016 .00155 .000001 39204 1296 2.590 .000001 .83612736 .0330578

.001285 1.356 .1383 4.186 .000947 107 .10198 3.4126

Energy Foot Pounds to British Thermal Un its Foot Pounds to Joules Foot Pounds to Kilogram Meters Gram Calories to Joules Joules to Rritish Thermal Units Joules to Ergs Joules to Kilogram Meters Watt Hours to British Thermal Unit

778 .7375 7.233 .2388 1055 .0093458 9.8117 .293

THICKENING T ANK REQ UIREM ENTS

___..

Flota tion Concentrates Slimes (Cyanide Plant) Easy Settling Ore Difficult Sett ling Ore

CONVERT

5 3 3 10

to to to to

12 10 6 40

sq. sq . sq . sq .

ft . ft . ft . ft .

per per per per

24 24 24 24

hr. hr. hr. hr.

ton ton ton ton

of of of of

solids solids solids sol ids

MILL FORMULAS

-

To estimate Circu lat ing Load of closed circuit operation of Ball Mill and Classifier having tons original feed and screen analys is of products : X equals tons classifier sands X = T(F - D ) T equals tons original feed D-SD equals % -200 Mesh in mill discharge F equals % -200 Mesh in classif ier overflow S equals % -200 Mesh in classifier sands If screen analyses are accurate any other mesh may be used , or better . solve for several meshes and get average fi gure . Ext racti on from assays of Heads , Concentrates and Tailings : Ratio of Concentration . E (H - T ) 100 C R C-T (C- T ) H H -T C_r.a::.. m ---=s.:/_ . . M~ i n;...,....,..* / T on o f 0 re Amount of Reagent used : - -=-=-=--= .315 x tons per 24 hrs.

=

=

= . ,.

WATER FACTS

MILL WATER REQU I REMENTS Cyanid e Circuits .............. 1 Flotat ion Circ u its ...... .. ...... 3 Tab le Circu its ............. ..... 5 J ig and Table C i rcuits ...... 6 Tab le a nd Amalgamation Circuits ........ ....... .. ..... .. 8-

-

3 5 7 10

Tons Tons Tons Tons

per per per per

ton ton ton ton

Cal . Water equals 8 .33 -tf equals 3 .785 liters Ton water equals 240 gals . equals 908 .49 liters Cu . Ft. water equals 7 .48 gallons

ore ore ore ore

Cal. per minute

12 Tons per ton ore

Tons Water per 24 hours 6

W ATER I N PI PES (Gallons per minute) Nominal Dia . of Pipe , D= 2/ U.S. g. p.m. x 0 .41 \ velocity in ft . per sec .

Pipe Dia . D at 6 ft . per sec . maximum

3 1/2

8 .2

14 .6

23

33

58

91

at 4 ft . per sec . nor mal

2 Y2

5 .5

9 .8

15

22

39

61

4

5

130

233

365

87

156

245

PULP CALCULATIONS

w Ws Wp

-

Gs Gp

s

equals weight of a given volume of water Ws equals weight of an equal volume of dry solids Cs = W-(Wp -Ws) equals weight of an equal volume of pulp , o r by wetting solids to make water level equal equals specific gravity of solids Cp- 1 equals specific gravity of pulp Ws = CsW Cs - 1 equals percent of solids in pulp Tons of dry sol ids per foot depth for s = 100 Cp -_! X Cs cp- rou nd tanks of diameter . D (in feet) . Cs- 1

Wp Cp = -w--

Cubic Ft . per ton

32.038 Cp

D2 (Cp-1 lCs 40 .8 (Cs- 1)

TEMPERATURE

-

Centigrade -The freezing point of water is 0 ° . The boiling point of water is 100° . The Centigrade scale is divided into 100 equal degrees between these points. Fah re nh eit-The freezing point of water is 32 ° . The boiling point of water is 212 ° . The Fahrenheit scale is divided into 180 equal degrees between these points. The same gradation above or below is used and when temperatures drop below the zero point a minus sign is pre-fixed . To convert degrees Fahrenheit into Centigrade subtract 32 , then multiply

that figure by 5 and divide by 9 . To convert Cent igrade into Fahrenheit multiply degrees by 9 and divide by 5 . then add 32. Reaumur Scale-The freezing ,::oint of water is 0 ° . The boiling r:;oint of water is 80 ° . The Reaumur scale is divided into 80 equal de grees between these points . To convert Fahrenheit into Reaumur subtract 32 and multiply that by 4 and divide by 9 . To convert Centi grade into Reaumur multiply by 4/5 .

41

AREAS AND CIRCUMFERENCES OF CIRCLES Dia .

I

/8

~

2

~

3

4 5 6

~· ~ ~· ~ V2

Y2 V2

Area

0 .0123 0 .0491 0 .11 04 0 .1 963 0 .3067 0 .4417 0 .60 13 0.7854 0 .9940 1.227 1.485 1.767 2 .074 2.405 2 .761 3.141 3 .976 4 .909 5 .940 7 .069 8 .296 9 .621 11 .045 12.566 15.904 19.635 23.758 28 .274 33.183

Cir.

.3926 .7854 1.178 1.570 1.963 2.356 2 .748 3.141 3 .534 3.927 4.320 4.712 5.105 5.498 5 .890 6.283 7.069 7.854 8 .639 9 .425 10.21 11 .00 11.78 12.57 14.14 15.71 17.28 18.85 20 .42

Dia .

Area

Cir.

Dla.

Area

Cir.

Dia.

Area

Cir.

Dia.

Area

Cir.

7

38.485 44 .179 50.265 56.745 63 .617 70.882 78 .54 86.59 95 .03 103.87 113. 10 122.72 132.73 143.14 153.94 165.13 176.71 188.69 201 .06 213 .82 226.98 240.53 254.47 268 .80 283 .53 298 .65 314.16 330.06

21.99 23 .56 25 .13 26 .70 28 .27 29.84 31.41 32.99 34.55 36.13 37.70 39.27 40 .84 42.41 43 .98 45 .55 47.12 48 .69 50.26 51.8 53.41 54.9 56.6 58.1 59.6 61.2

21 V2 22 23 Y2 V2 24 V2 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

346.36 363.05 380.13 397.61 415.48 433 .74 452 .39 471.44 490.87 530.93 572.50 615.75 660.52 706.86 754 .77 804 .25 855 .30 9C7.92 962 .11 1017.9 1015.2 1134.1 1194.6 1256.6 1320.3 1385.4 1452.2 1520.5

65 .97 67.54 69. 11 70.69 72 .26 73 .83 75.40 76 .97 78 .54 81 .68 84 .82 87.96 91.11 94 .25 97 .39 100.5 103.6 106.8 109.9 113.1 116.2 119.4 122.5 125.7 128.8 I 31.9 135.1 138 .2

45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72

1590.4 1661 .9 1734.9 1809.5 1885.7 1963.5 2042 .8 2123 .7 2206 .1 2290 .2 2375 .8 2463 .0 2551.8 2642.0 2734 .0 2827.4 2922 .5 3019.1 3117.2 3217 .0 3318.3 3421.2 3525.7 3631.7 3739.3 3848.5 3959.2 4071 .5

141.4 144 .5 147.7 150.8 153.9 157 .1 160.2 163.4 166.5 169.6 172.8 175.9 179.0 182.2' 185.-4 188 .5 191.6 194.8 197.9 201.1 204 .2 207 .3 210.5 213.6 216 .8 219 .9 223 . 1 226 .1

73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99

4 185.4 4300.8 44 17.9 4536 .5 4656.6 4778 .4 4901 .7 5026.5 5153 .0 5281.0 5410.6 5541 .8 5674.5 5808.8 5944 .7 6082. 1 6221 . 1

229.3 232 .5 235. 6 238 .7 241.9 245 .0 248 .2 25 1.3 254 .5 257 .6 260 .7 263 .9 267 .0 270 .2 273.3 276 .5 279 .6 282.7 285 .9 289 .0 292 .2 295 .3 298.4 301 .6 304.7 307.9 311.0

8 9 10

V2 V2 V2 V2

11 12 V2 V2 13 V2 14 V2 15 16 17 18 19 20

Y2

V2 V2

Y2 V2 V2

~Uc

~361.7

6503 .8 6647 .6 6792 .9 6939 .8 7088 .2 7238 .2 7389 .8 7543 .0 7697.7

Electrical Abbreviations A. C. D.C. E Eff. H.P.

I

Alternating Current Direct Current Electromotive force in volts % Effic iency Horsepower Current in amperes

K.V .A. Kilo-volt amperes K.W . Kilowatts p Power P.F. Power factor Resistance in ohm:; R

OHMS LAW

KW

E I =~

E = IR I KW =Ex 1000 KW =

KW =

= EX I X P.F. 1000

E R = 1-

(Si ngle phase A.C. l

KW

K.V .A.

(D .C. only)

1.73 X EX I X P.F. 1000

(3 phase A.C. )

p F · ·

2xExlxP.F. 1000

(2 phase A.C.)

KW

=

= P.F.

KW KVA

Watts Volts x Am peres

= .746

X

HP

HP = 1.34

X

KW

CURRENT INPUT PER LINE (AMPERES PER MOTOR)

2 X EX Eff. X P.F. HP X 746

For D.C.

I=

HP X 746 EX Eff.

For 2 Phase A.C.

I=

For Single Phase A.C.

HP X 746 I = EX Eff. X P.F.

For 3 Phase A.C.

IHP X 746 - 1.73 X EX Eff. X P.F.

SCREEN DATA Inches

MESH

3 4 5 6 8 10 12 14 16 20 25 28 35 48 50 60 65 70 80 100 120 150 200 270 325 400 Microns 22 .0 18.5 13. 1 11. 0

TYLE R SCALE Openings Mi llimeters

1. 050 .7 42 .525 .371 .263 . 185

26 .67 18 .85 13 .33 9 .423 6 .680 4 .699

.1 49 . 135 . 105 .092 .070 .065

. 131 093 .065

3.327 2 .362 1.651

.036 .032 .035

.046

1. 168

.025

.032 8

.833

.0 172

.0232 .0164 .0116

.589 .417 .295

.0125 .0122 .0092

.208

.0072

.0069 .0058

. 175 . 147

.0056 .0042

.0041 .0029 .0021 .0014 .0015

. 104 .074 .053

.0026 .0021 .0016 .0014 .0010

.038

Theoretical Mesh 673 800 1130 1346

Microns 9 .3 7.8 5 .5 3 .9

r

Adequate foundations for any heavy equipment, and in particular Marcy grinding mills, are extremely important to assure proper operation of that equipment. Any slight settling of foundations will cause bearing and gear misalignment, resulting in excessive wear and higher maintenance costs. It has been found that concrete foundations on a weight basis should be approximately 1 Y2 times the total weight of the grinding mill with its grinding med ia. Allowable bearing pressure between concrete footings and the soi I upon which the foundation rests should first be considered . The center of pressure must al~ays pas~ through the center of the footing . F~undat 1ons . subject to shock should be designed w1th less un 1t pressures than foundat ions for stationary loads. High moisture content in soils reduces the amount of allowa ble pressure that that material can support. The fo llow ing f igures may be used for quick foundation calculations : TYPE OF MATERIAL

Soft Cla y Dry Sand Dry thick Cla y Soft Rock Grave l and Coarse Sand Hard Rock (partia lly broken ) Hard Rock (slightly broken ) Hard Rock (i n na tural surroundings)

BEARING LOAD IN TONS PER SQUARE FOOT 1 - 2 1Y:z- 3 Y2

3 5

- 6

- 9 7 - 10 15 - 20 20 - 30 Up to 200

U. S. BUREAU OF STA NDARDS Ope nings Inches M icrons 25 ,400 19 ,100 12,700 9 ,520

1 .75 .5 .375 . 187 .157 . 13 2 .0937 .07 87 .0661 .0555 .0469 .0331 .0280 .0197 .0 117 .0098

.0082

CONCRETE FOUNDATIONS

r:

Dia mete r of Wire - Inches

Theoretical Mesh 1590 1898 2690 3800

.0083 .0070 .0059 .0049 .002 9 .0021 .0017 .0015 Microns 2. 8 1.64 1.16 .82

4,760 4 ,000 3 ,360 2 ,380 1,680 1,4 10 1, 190 1,000 840 710 590 4 20 297 250 210 177 149 125 105 74 53 44 37 Theoretical Mesh 5 ,280 9 ,030 12 ,7 80 18 ,000

An accurate determination by experimentation and close examination should be made to check the exact soi I characteristics. Portland cement mixed with sand and aggregate in the proper proportions has come to be standard practice in making concrete . For general reference cem.ent is usually ~hipped in sacks conta ining one cub~c foot of matenal. A barred usually consists of 4 cu?lc feet . Cement will deteriorate with age and will qu1ckl y absorb moisture so it should be stored in a cool , dry place. The sand and gravel used should be carefully cleaned for best results to be sure of m inimizing the amount of sedimentation in that material. Concrete may be made up in different mixtures having different proportions of sand and aggregate . These are expressed in parts- for example a 1:2 :4 mixture indicates one bag of cement, 2 cubic feet of sand , and 4 cubic feet of gravel . We recommend a mixture of 1:2 :3 for ball mill and rod m ill founda tions . The proper water to sand ratio should be carefully regulated since excess water wi II tend to weaken the concrete even more than corresponding variat ions in other material ratios. Between S Y2 to 8 Y2 gallons of water to a sack of cement is usually recommended , !he lov.:-er amount to be used where higher stre ngth IS requ1red or where the concrete will be subject to severe weathering condit ions.

4

Pages

Length of mill Liner backing Liner bolts Liners Lorain liners Lubricant jacks Lubrication

Pages

Adjustment of gear and p inion 16 Advantages of the Ma rcy M i ll 4 , 24 , 25 , 31 Areas of circl es 42 Ball charge 8 , 12, 13 , 30 Ball Mills 5 , 30 Balls 5 , 12, 13 ,aearings 16 ushings 16 Capacity 10 , 11 , 12, 25 , 28 , 31, 35 Cement grinding 38 , 39 Center Peripheral Discha rge 20 , 28 Circulat ing load 7 , 30 , 41 Circumference of Ci rc les 42 Classification 7 , 30 Closed circuit grind ing 7 Coke grinding 36 , 37 Concrete facts 43 Combination feeders 23 Construction 2, 14 Conversion tables 40 Critical speed 8, 9 , 22 Decimal equivalents 40 Diameter 10 , 11 ; 24 , 30 Dilution 10 , 23 , 25 Dimensions 27 , 33 Direct connected d ri ve 23 20 , 3 1 Discharge Discharge head 15 rrives 22 , 23 rum feeder 23 Dry grinding 4 , 5, 10 , 25 , 28 , 36 , 37 Electrical fo rmulas 42 End peripheral discharge 28 Extraction 41 Feed characteristics 4 , 11' 34 Feed head 15 Feeders 22 , 23 Fine crushing 7 , 23 Fineness of grind 4 , 5 , 10 , 11 ' 25 , 30 , 34 Foundations 43 Gears 17 Grates 21, 30 , 34 Grinda bilit 3, 6 Grindi ng media 5, 10 , 12, 13 , 35 Hand of mill 27 Head liners 18 Heads 15 Helical gears 17 Herringbone gea rs 17

44

6 . 10 18 18 18. 35 18 16 16

Pages

Manufacturing facilities Manufacturing methods Marcy principle of grinding 1, 4, Media 5 , 10, 12, Meehanite Metal reclaiming Microns

,..

2 2 , 14 20, 30 13 , 35 14 , 19 3 6 , 37 43

Pages

Mill dimensions Mill selection Mill sizes Mill weights Motors Open circuit grinding Open end rod mills Overflow mills Overgrinding Pebble mills Pebbles Peripheral discharge Per ipheral speed Pinions Pinion shaft Pinion shaft bearings Power Pulp calculat ions Pulp level Ratio of concentration Reagent consumption Regrinding Rod charge Rod mills Rods Rubber lining Sand grinding Scoop feeder Screen data Shape of mill Shell Shell liners Single hel ical gears Single stage grind ing Special features Speed reducer drive Speeds Spout feeders Spur gears Steel consumption Technical serv ice Temperature Testing facilities Thickening Trunnion bearings Trunnion liners Trunnions Tube mills Two-stage grinding Tyler screen s ize

27 , 33 3. 4 24 , 30 , 34 24 , 30 , 34 22

7 21 20 , 31 4 , 5 , 20 34 , 35 35 20 . 28 8, 9 . 25 17

):{ 10. 11 . 12 , 24 , J I 41 20 , 30 41 41 5 , 34 12. 24 4 , 23 . 24 12, 13 17 28 22 43 6 , 28 14 18 17 5, 7 17 23 5. 8. 24 . 17 12. 28

2 41

3 40 16 15 15 34 , 35

7 43

V-belt drives Volume

22

Water facts Wet grinding

41 4 . 5, 10 , 28

24

45

JHE ORE & CHEMICAL CORPORATION

235 East 42nd Street New York, N.Y. 10017

MINE AND SMELTER SUPPLY CO. MANUFACTUR ING DIVISION Executive Offices and Main Plant: 3800 Race St., P.O. Box 9041 Denver 16, Colorado

Branch Offices: Albuquerque, New Mexico; 701 Haines Ave, N.W. El Paso, Texas ; 1515 Eleventh Ave. New York City, N.Y.; 122 East 42nd Street Salt Lake City, Utah; 375 West 21st Street San Jose, Calif.; 1636 Nord Lane Tucson, Ariz. ; P.O. Box 849

Main Export Office: Denver, Colorado, U.S.A.

Cable Address: MINTERPLY

Please write our Denver, Colorado office for names and addresses of our fore ign licensed manufacturers and sa les agents .

Prin ted in U.S.A.