Pennsylvania. State University. College of Earth and Mineral Sciences. Experiment Station. Coal Research Section. Special research report.

Transcription

1 Pennsylvania. State University. College of Earth and Mineral Sciences. Experiment Station. Coal Research Section. Special research report.

2 SPECIAL REPORT OF RESEARCH Conducted in Department of Mineral Preparation College of Mineral Industries The Pennsylvania State University THE EFFECT OF CRUSHER TYPE ON THE LIBERATION OF SULFUR IN BITUMINOUS COAL by D.W. KESTNER, JR. D.S. CONFER H.B. CHARMBURY An Investigation Conducted Under the Auspices of the COAL RESEARCH BOARD of the COMMONWEALTH OF PENNSYLVANIA Contract Number CR-29 Special Research Report Number SR-32 April 29, 1962

3 STATEMENT OF TRANSMITTAL Special Report SR-32 transmitted herewith has been prepared by the Coal Research Section of the Mineral Industries Experiment Station. Each of the Special Reports presents the results of a phase of one of the research projects supported by the Pennsylvania Coal Research Board or a technical discussion of related research. It is intended to present all of the important results of the Coal Board research in Special Reports, although some of the results may already have been presented in progress reports. The following is a list of Special Research Reports issued previously. SR-1 SR-2 SR-3 SR-4 SR-5 SR-6 SR-7 SR-8 SR-9 The Crushing of Anthracite Petrographic Composition Sulfur Con tent of a Column of Pittsburgh Seam Coal The Thermal Decrepitation of Anthracite The Crushing of Anthracite with A Jaw Crusher Reactions of a Bituminous Coal with Sulfuric Acid Laboratory Studies on the Grindability of Anthracite and Other Coals Coal Characteristics and Their Relationship to Combustion Techniques The Crushing of Anthracite with an Impactor-Type Crusher The Ignitibility of Bituminous Coal (A Resume of a Literature Survey) May 31, 1958 August 1, 1958 September 15, 1958 November 1, 1958 February 1, 1959 April 1, 1959 April 15, 1959 April 25, 1959 May 4, 1959

4 SR-10 SR-11 SR-12 SR-13 Effect of Gamma Radiation and Oxygen at Ambient Temperatures on the Subsequent Plasticity of Bituminous Coals Properties and Reactions Exhibited by Anthracite Lithotypes Under The rmal Stress Removal of Mineral Matter from Anthracite by Chlorination at High Temperatures Radiation Stability of a Coal Tar Pitch May 6, 1959 May 11, 1959 June 22, 1959 June 25, 1959 SR-14 The Effect of Nuclear Reactor July 31, 1959 Irradiation During Low Temperature Carb>onization of Bituminous Coals SR-15 SR-16 Effect of Anthracite and Gamma Radiation at Ambient Temperatures on the Subsequent Plasticity of Bituminous Coals The Isothermal Kinetics of Volatile Matter Release from Anthracite August 5, 1959 August 25, 1959 SR-17 The Combustion of Dust Clouds November 30, 1959 a Survey of the Literature SR-18 SR-19 SR-20 The Ignitibiliy of Bituminous Coal Changes in Coal Sulfur During Carbonization The Radiation Chemistry of Coal in Various Atmospheres June 15, 1960 August 1, 1960 September 12, 1960 SR-21 SR-22 Reaction of Bituminous Coal October 1, 1960 with Concentrated Sulfuric Acid The Nature and Occurrence of December 30, 1960 Ash Forming Minerals in Anthracite

5 SR-23 SR-24 SR-25 SR-26 SR-27 SR~28 A Phenomenological January 20, 1961 Approach to the Batch Grinding of Coals The Unsteady State Diffus- January 31, 1961 ion of Gases from Anthracite at High Temperatures Some Advances in X-Ray February 24, 1961 Diffractometry and Their Application to the Study of Anthracites and Carbons The Filtration of Coal March 17, 1961 Solutions A Preliminary Invest- May l, 1961 igation into the Application of Coal Petrography in the Blending of Anthracite and Bituminous Coals for the Production of Metallurgical Coke Preparation and Properties of August 15, 1961 Activated Carbons Prepared from Nitric Acid Treatment of Bituminous Coal SR-29 SR-30 SR-31 The Reactions of Selected Bituminous Coals with Concentrated Sulfuric Acid Investigations on the Operation of the Circular Concentrator for Cleaning Fine Coal Mineral Matter Removal from Anthracite by High Temperature Chlorination August 31, 1961 February 26, 1962 March 26, 1962 M. E. Bell, Director M. I. Experiment Station

6 SUMMATION OF RESULTS Seven different types of industrial crushers were investigated to determine their ability to liberate pyritic sulfur in a bituminous coal. The coal used in the investigation was obtained from the Upper Freeport seam in Western Pennsylvania. The run of mine coal after crushing to a top size of 4 11 was screened at 1-1/2 11 and the 4 11 x 1-1/2 11 size fraction was further reduced in size to minus 1-1/2 11 using the various types of crushers. The crushers used in the investigation were the coalpactor, impactor, jaw, gyratory, single roll, granulator, and cuber. The degree of liberation was evaluated by determining the percentage of sulfur reporting to the specific gravity sink fraction in each of six size fractions smaller than 1-1/2 11 In addition, sink-float studies were conducted at specific gravities of and to determine the characteristics of the clean coal from the crusher products. This data also provides information on the sulfur rejection at these specific gravities. In summarizing and evaluating these crusher tests, two facts were evolved. First, it was found that the single roll crusher which is most predominantly used in the coal industry today in the United States is the poorest type of crusher as far as pyritic.sulfur liberation and subsequent sulfur removal on cleaning are concerned; and second, that either the jaw, coalpactor, gyrator or cuber crushers would be much more highly desirable for this purpose.

7 ACKNOWLEDGMENTS The authors wish to express their sincere appreciation to the Altmire Brothers Coal Company for permitting the staff to visit their coal preparation plant and obtain the sample of 4" x. 0 coal used in this work. The authors are also indebted to the Pennsylvania Crusher Division of the Bath Iron Works for supplying their crushers used in this work and permitting our staff to work with them in conducting the crusher tests. The same expression of appreciation is also extended to the Kennedy Van Saun Company for their cooperation in these tests.

8 111 TABLE OF CONTENTS Page INTRODUCTION CRUSHERS USED IN SULFUR LIB-ERATION STUDIES 2 Toothed Single Roll Crusher 2 Jaw Crusher... 5 Gyratory Crusher 7 Impactor Crusher. 9 C oalpactor Crusher. 11 Cuber Crusher.. 11 Granulator Crusher 14 COAL SAMPLE 14 PROCEDURE. 25 Crusher Tests 25 Screen Analysis 25 Washability Tests 26 Chemical Analyses 28 RESULTS. 30 DISCUSSION 80

9 iv List of Tables Table Page I Screen Analysis of Original Coal Sample. 16 II III IV V VI VII VIII IX X XI XII XIII XIV Washability Data on the 4" x. 1-1/2" Original Coal Sample Screen and Chemical Analyses of Original Minus 1-1/2 Inch Coal Sample 0 21 Washability Data on Minus 1-1/2 Inch Size Fractions of Original Coal Sample 22 Per Cent Sulfur Liberation in Various Sizes Smaller Than 1-1/2 Inches in the Original Coal Sample 0 23 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Single Roll Crusher Using 3/4" Inch Set o 31 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Single Roll Crusher Using a 7/16 Inch Set 0 32 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Jaw Crusher Using a 1 Inch Set 33 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Jaw Crusher Using a 1/2 Inch Set 0 34 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Gyratory Crusher Using a 5/8 Inch Set Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Gyratory Crusher Using a 7/8 Inch Set. 36 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Impactor Crusher Operating at 300 RPM. 37 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Impactor Crusher Operating at 500 RPM. o 38 Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Coalpactor Crusher Operating at 720 RPM. 39

10 v Table XV XVI XVII XVIII XIX XX XXI XXII XXIII XXIV XXV XXVI XXVII Screen and Chemical Analyses of Minus Inch Product from Cuber Crusher Operating at 680 RPM. Screen and Chemical Analyses of Minus 1-1 I 2 Inch Product from Cuber Crusher Operating at 1050 RPM Screen and Chemical Analyses of Minus Inch Product from Granulator Crusher Ope rating at 600 RPM.. Washability Data on Minus Inch Size Fractions in Product from Single Roll Crusher with a 314 Inch Set Washability Data on Minus l-li2inch Size Fractions in Product from Single Roll Crusher with a 7 I 16 Inch Set. Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from Jaw Crusher with a 1 Inch Set. Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from Jaw Crusher with a 1 I 2 Inch Set. Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from Gyratory Crusher with a 518 Inch Set. Washability Data on Minus Inch Size Fractions in Product from Gyratory Crusher with a 7 18 Inch Set Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from Impactor Crusher Operating at 300 RPM Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from Impactor Crusher Operating at 500 RPM Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product from C oalpactor Crusher Operating at 7 20 RPM. Washability Data. on Minus Inch Size Fractions in Product from C uber Crusher Operating at 680 RPM. Page

11 vi Table XXVIII Washability Data on Minus 1-1/2 Inch Size Fractions in Product from Cuber Crusher Operating at 1050 RPM, XXIX Washability Data on Minus 1-1/2 Inch Size Fractions in Product from Granulator Crusher Operating at 600 RPM 55 XXX.,P.er.-C.ent.Sulfur Lib.eration in the Minus 1-1/2 Inch Size Fractibns of the Product from the Single Roll Crusher with a 3/4 Inch Set.. 56 XXXI Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Single Roll Crusher with a 7/16 Inch Set 57 XXXII Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Jaw Crusher with a 1 Inch Set XXXIII Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Jaw Crusher with a 1/2 Inch Set XXXIV Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of tre Product from the Gyratory Crusher with a 5/8 Inch Set 60 XXXV Per Cent Sulfur Liberation in the Minus 1-l/2 Inch Size Fractions of the Product from the Gyratory Crusher with a 7 /8 Inch Set. 61 XXXVI Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Impactor Crusher Operating at 300 RPM. 62 XXXVII Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Impactor Crusher Operating at 500 RPM 63 XXXVIII Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Coalpactor Crusher Operating at 7 20 RPM 64 XXXIX Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Cuber Crusher Operating at 680 RPM.. 65 XL Per Cent Sulfur Liberation in the Minus 1-1/2 Inch Size Fractions of the Product from the Cuber Crusher Operating at 1050 RPM 66

12 vii Table XLI XLII XLIII XLIV XLV XLVI Per Cent Sulfur Liberation in the Minus 1-1 I 2 Inch Size Fractions of the Product from the Granulator Crusher Operating at 600 RPM Comparison of Size Analyses of Products from the Different Crushers Under Different Conditions. Percentage of Minus Inch Material from the Crushing Tests to Report in the Specific Gravity Sink Fraction... Per Cent Sulfur Liberation in Minus 1-1 I 2 Inch Sizes from the Crusher Tests and tre Natural Product Coal Cleaning Sulfur Liberation Values Based Upon Liberation and Efficiency Factors. Quantity and Quality of Clean Coal and Per Cent Sulfur Rejection on Cleaning Various Products at Specific Gravities of and Page

13 viii List of Figures Figure 1 Toothed Single Roll Crusher 4 2 Kue-Ken Jaw Crusher 6 3 Gyratory Crusher. 8 4 Reversible Impactor Crusher 10 5 C oalpactor Crusher 12 6 Cuber Crusher Granulator Crusher 15 8 Theoretical Flowsheet for Cleaning 4 11 x. 1-1/2 11 Original Coal Sample at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1 I 2 Inch Original Coal Sample at Specific Gravities of and Special Separatory Vessels Used for Washability Studies with the 3/8 Inch x. 20 Mesh, 20 x. 48' Mesh, and 48 x. 100 Mesh Size Fractions Special Separatory Tubes and Centrifuge Used for Washability Studies with the Minus 100 Mesh Size Fractions Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Single Roll Crusher Using a 3/4 Inch Set at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Single Roll Crusher Using a 7/16 Inch Set at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1(2 Inch Product from the Jaw Crusher Using a 1 Inch Set at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Jaw Crusher Using a 1/2 Inch Set at Specific Gravities of and Page

14 ix Figure Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Gyratory Crusher Using a 5/8 Inch Set at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Gyratory Crusher Using a 7/8 Inch Set at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Impactor Crusher Operating at 300 RPM at Specific Gravities of and Theo-retical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Impactor Crusher Operating at 500 RPM at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the C oalpactor Crusher Operating at 7 20 RPM at Specific Gravities of and Theoretical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the C uber Crusher Operating at 680 RPM at Specific Gravities of and Theoretical Flow sheet for Cleaning Minus 1-1/2 Inch Product from the C uber Crusher Operating at RPM at Specific Gravities of and The ore tical Flowsheet for Cleaning Minus 1-1/2 Inch Product from the Granulator Crusher Operating at 600 RPM at Specific Gravities of and Page

15 1 INTRODUCTION One of the problems of great concern to many of the bituminous coal producers in Pennsylvania is the removal of sulfur from run-of-mine coal. Approximately 70 per cent of the sulfur in coal remains in the coke when the coal is carbonized thus lowering the grade of the coke used for steel production. Practically 100 per cent of the sulfur in coal is released into the atmosphere when the coal is burned thus causing corrosion and atmospheric pollution problems. Today, a satisfactory clean coal product is generally made by scalping the run-of-mine coal at some size in the range of 3 to 8 inches, crushing of oversize to the scalping size and then cleaning the material in single or multiple units. The run-of-mine material being produced today as compared to a few years ago is generally higher in ash and sulfur. This is due to advanced mechanization methods and to a decrease in grade of the mineable coal. Consequently, in all probability in the future as the run-of-mine product continues to decrease in grade, it will be necessary to crush the coal to a smaller size prior to cleaning to obtain satisfactory liberation of the sulfur -containing particles. Most of the sulfur in Pennsylvania bituminous coals 1s present as pyrite or marcasite, and this type of sulfur can be removed by conventional methods of gravity cleaning and to a

16 2 limited extent by the froth flotation p-oces s. No method of coal beneficiation has been developed to date to remove organic sulfur economically. Naturally, the crushing of coal to obtain pyrite or marcasite liberation will have to be performed to produce maximum liberation with minimum size reduction. The smaller the particle size the more difficult and more expensive the coal cleaning operation. It is well known that coal cleaning efficiencies decrease with a decrease in particle size. It is also well known that due to the auxiliary equipment required to recover the coal from its air or water cleaning medium there is an increase in the coal cleaning costs with a decrease in particle size. It was, therefore, the object of this work to investigate the conventional mineral crushing equipment on the market today to determine the effect of different types of crushers on the liberation of sulfur when crushing to a top size of 1-1/2 inches. Since pyrite and marcasite have specific gravities greater than the pure coal and other associated impurities (4. 40 as compared to and 2. 65), the degree of sulfur liberation was determined as the percentage of sulfur in any given size reporting to the specific gravity fraction. Crushers Used in Sulfur Liberation Studies Toothed Single Roll Crusher Since the toothed single roll crusher is the one most currently used in the coal industry today, it was decided to include this

17 3 type crusher in the study. This type of crusher consists of a toothed roll and a stationary breaking plate. It is driven with a gear and pinion by means of a belt drive pulley. The breaker plate which is hinged at the top is equipped with a set of compression springs to permit the plate to move back in the event an unbreakable material enters the crusher. These crushers are manufactured with roll diameters ranging from 18 to 60 inches and with lengths 1-1/2 to 3 times the diameter. They generally operate with a speed of 200 to 300 RPM. The operation of this type crusher is illustrated in Figure 1. The pilot plant crusher used in this study had a 10-inch diameter roll 10 inches long equipped with teeth for shearing the particles held against the breaking plate. The crusher was operated at a speed of 114 RPM. The action of the teeth on the roll helped to facilitate the removal of the crushed particles from the crushing zone and thus prevented mechanical choking. Two tests were conducted with this type of crusher; one with a set of 3/4 inch and another with a 7/16 inch set. In each case 100 per cent of the crushed material passed the 1-1/2 inch screen opening size. With the former set (3/4 inch) 2. 1 per cent of the particles were larger than 1 inch and per cent were larger than 3/4 inches. With the 7/16 inch set, 100 per cent of the particles passed a 1 inch screen and only 13.8 per cent were larger than 3/4 inch.

18 4 TOOTHED SINGLE ROLL CRUSHER Figure 1

19 5 Jaw Crusher. Jaw crushers are reciprocating pressure-breakers. They consist essentially of two crushing surfaces, one fix.ed and the other movable which alternately approaches and recedes from the fix.ed surface. The movable plate may be hinged at the top or bottom. The former is called the Blake type and the latter the Dodge type. The Blake type is the better known of the two. These crushers are particularly suitable for the reduction of highly abrasive materials because the basic crushing action is pressure. Jaw crushers also have the advantage of being able to take cooke feeding. One disadvantage of the jaw crusher is the passing of flat or slab by pieces. The size consist of the product primarily depends upon the set or discharge opening of the crusher. A change in speed affects capacity and power consumption, but there is no marked effect on size consist with straight jaw plates. However, increasing the speed with curved plates tends to give a finer discharge. The pilot plant jaw crusher used in this study is identified as a #35 Kue Ken crusher manufactured by the Pennsylvania Crusher Company. It is illustrated in Figure 2. The unique feature of this type of crusher is that the combination of smooth jaw plate design and movable jaw action crushes material without rubbing and with a minimum of abrasion thus resulting in a minimum amount of fines. Two tests were made with this type of crusher both with a speed of 385 RPM; one with a 1 inch set and the second with a

20 6 KUE-KEN JAW CRUSHER Figure 2

21 7 1/2 inch set. In the former test (1 inch set) 5.1 per cent of the resulting product was larger than 1-1/2 inches and in the latter test (1/2 inch set) all particles passed the 1-1/2 inch size screen. Gyratory Crusher The gyratory crusher is a receiprocating pressure-type breaker which transmits its load gradually to the particles. It consists essentially of a fixed crushing surface in the form of an inverted cone and a movable crushing surface which rotates and gyrates to and from all points on the fixed surface. The material is crushed as the surfaces approach each other and the crushed material is released as the surfaces recede. There are many different types of gyratory crushers but the suspended spindle type is the best known. These crushers range in size on the commercial market to handle particles up to 6 feet at a capacity of 5000 TPH. The pilot plant gyratory crusher used in this work could handle particles up to 4 inches in size with a capacity of about 35 T PH. It was a roller bearing gearless suspended spindle type manufactured by the Kennedy Van Saun Company. It is illustrated in Figure 3. Two tests were made with this crusher both with a speed of 1200 RPM. The first had a closed set of 5/8 inch and an open set of 1-1/8 inch and the second hq.d a closed set of 7/8 inch and an open set of l-3/8 inch. In both tests the crushed products were 100 per cent minus 1-l/2 inch. The product from the former test (5/8 inch set) had 16.4 per cent of its particles retained on the 3/4 inch screen and the product from the latter test (7/8 inch set) had per cent retained.

22 8 GYRATORY CRUSHER Figure 3

23 9 Impactor Crusher The impact type of crusher consists of a rotor on a horizontal axis with a number of hammers and a.number of breaker plates. The material is broken by the blow of the hammers and by the impact of the broken particles against the breaker plates. The hammers may be either fixed or hinged and the breaker plates may be either a straight, arc, or bar screen type. These crushers have a relatively large reduction ratio in comparison to other types of crushers. The prmciple variables which determine the size consist of the product are the type of rotor and its speed, the type of breaker plate and its distance from the hammer tip, and the drop height into the breaker. The pilot plant crusher used in this work was a reversible, single rotor, arc-plate type. It is illustrated in Figure 4. The feed entered a centrally located chute directly above the rotor from a height of 1 foot. The feed rate was approximately 8-1/2 TPH. The clearance between the tip of the hammer and the breaker plate was 4 inches. Two tests were made with this crusher, one with a rotor speed of 300 RPM and another with a speed of 500 RPM. The former test ( 300 RPM) made a product with 7. 2 per cent plus 1-1/2 inch. The product from the second test (500 RPM) was 100 per cent minus 1-1/2 inches with about 5 per cent of the particles being retained on a 1 inch screen.

24 10 REVERSIBLE IMPACTOR CRUSHER Figure 4

25 ll C oalpactor Crusher The coalpactor crusher is an impactor type especially designed to handle softer materials such as coal. It is illustrated in Figure 5. Only one test was made with this crusher. The feed was dropped into the crusher from a height of 2 feet at the rate of about TPH. The rotor speed was 720 RPM and the distance between the tip of the hammer and the breaker plate was 4 inches. These conditions were based upon the company's experience to make a product with the minimum amount of fines. The product from this test was 100 per cent minus 1 inch with 4. 4 per cent of the particles retained on the 314 inch screen. Cuber Crusher The cuber crusher is also an impactor-type. The rotor 1n this type crusher has three fixed hammers 6 inches high and 2-1 I 2 inches thick that run across the length. This is illustrated in Figure 6. Two tests were made with this crusher, one with a rotor speed of 680 RPM and a feed rate of about 8-1 I 2 TPH and the second with a speed of RPM and ll-1 12 TPH. In each case the feed was dropped into the crusher from a height of 2 feet. The former test ( 680 RPM) made a product with 4-1 I 2 per cent plus 1-1 I 2 inch size particles and the product from the latter test only had 3-1 I 2 per cent retained on a 1-1 I 2 inch screen.

26 12 COALPACTOR CRUSHER Figure 5

27 l3 I l1 II I. lp 1. 1 I. Ill I!II I CUBER CRUSHER Figure 6

28 14 Granulator Crusher The granulator crusle r is an impactor type in which the end of the hammer consists of heavy rings that make contact with the feed. It also has a bar setting for the discharge of the crushed product. The operation of this particular type crusher is illustrated in Figure 7. This type is being used to crush run- of-mine and slack bituminous coal to industrial and domestic stoker sizes. The capacity of this type crusher ranges to 600 TPH. The pilot plant size crusher used for the present work operated at 600 RPM and had a bar setting of 3 inches. The feed was dropped into the crusher from a height of 2 feet and at a rate of about 10 TPH. Under these conditions the product was 100 per cent minus 1 inch with 8. 5 per cent retained on a 314 inch screen. Coal Sample The coal used in these crushing tests was obtained from the Altmire Brothers coal preparation plant at Apollo, Pennsylvania. It was mined from the Upper Freeport seam. The run-of-mine coal at this plant is crushed in a toothed single roll crusher with a 4 inch set before cleaning by jigging. The sample of 4" x 0 runof-mine coal was taken in small increments over a 3-1 I 2 hour period until a total of 3400 pounds was obtained. The screen analysis of the sample is presented in Table I. The data indicates that 55.9 per cent of the crushed material is smaller than 1-1 I 2 inches,

29 15 GRANULATOR CRUSHER Figure 7

30 16 Table I Screen Analysis of Original Coal Sample S1ze-Inches and Mesh C urn ula ti ve Passing - Retained Weight% Retamed - Passing 4" 1-1/ /2 11 3/ / M M 48M M loom loom

31 17 The original sample was screened at inches and a total weight of 1500 pounds of 4 11 x material was obtained for the crushing tests. This sample was thoroughly mixed, coned and quartered, and the various fractions of about 65 to 70 pounds set aside for the individual tests. Washability studies were made on the 4 11 x. 1-1/2 11 fraction to determine the sulfur distribution and to learn if there was any sulfur liberation in this size range. The results are presented in Table II along with ash and sulfur analyses of all specific gravity fractions. Since there was no sink material there was no sulfur liberation. Further, the data indicates that per cent of the sulfur was in the float fraction of this s The sulfur in the 1, 40 sink,-1, 60 float fraction amounted to 6. 8 per cent of the total and that i.n the sink fraction was 16.8 per cent. Figure 8 is a flowsheet to -sh O'':i'T the theoretical quantity and quality of the clean coal and refuse products to be obtained if the 4 11 x. 1-1 I 2 11 fraction were cleaned at specific gravities of and The figure also shows that per cent of the sulfur would be rejected if the coal were cleaned at and that per cent would be rejected if it were cleaned at The minus 1-1 I 2 11 for a screen analysis. fraction of the original sample was used Then washability data was obtained on each size fraction. The screen analysis is presented in

32 Specific Gravity WL Sink - Float % L L 40 l L " Table II Washability Data on the 4 11 x 1 l/2 11 Original Coal Sample o/o --cumulative Ffoat C um-u:ia five Siiil< o/o Sul- - % Sui- % Suio/o Sul- fur WL o/o Sul- fur WL o/o Sul- fur Ash fur Dist. % Ash fur Dist. o/o Ash fur DisL 5.6 L L L ~' L L L L ' (X)

33 19 Figure 8 Theoretical Flowsheet for Cleaning 4 11 x. 1-1/2 11 Original Coal Sample at Specific Gravities of 1.40 and 1.60 (Basis: 100 tons original coal) tons original coal 12.3% ash % s ulf u r ~- -- v Cleaned at specific gravity v Cleaned at specific gravity ~ \1 ~ Clean Coal Refuse Clean Coal Refuse tons tons tons 14.5 tons 5. 6 % ash 41.1 %ash 6. 7% ash 45.4% ash 1. 39% sulfur 1. 86% sulfur 1. 44% sulfur 1. 73% sulfur 23.6% of sulfur 16. 8% of sulfur rejected rejected J

34 20 Table III along with ash and sulfur analyses of all sizes. The results are typical in that they show an increase in the per cent ash and an increase in the per cent sulfur with a decrease in size. Table IV presents washability data on each size fraction. These data show, using the sink material as a guide, that in the natural product sulfur liberation does not occur in the 1-1/2" x. 3/4 11 size fraction but that it does occur in size fractions smaller than 3/4 inch. The data also shows that the per cent of sink material increases with a decrease in size. This same relationship is shown in Table V along with data to show how the per cent sulfur liberation increases with a decrease ins in the natural product. The per cent sulfur liberation is the percentage of sulfur in any given size fraction that reports to the specific gravity sink fraction. The data in Table V shows an increase in the per cent sulfur liberation with a decrease in size from per cent in the 3/4 n x. 3/8 11 s to per cent in the minus 100 mesh. For the entire 1-1/2 11 x 0 fraction of original coal per cent of the sulfur is liberated and reports in the specific gravity sink fraction. Figure 9 presents a theoretical flowsheet for cleaning the minus 1-1/2 inch original coal at specific gravities of 1.40 and based upon the washability data. The data in this figure indicates that per cent of the sulfur would be rejected if the coal were cleaned at a specific gravity of and that per cent would be rejected if it were cleaned at a gravity of

35 Table III Screen and Chemical Analyses of Original Minus 1 1/2 Inch Coal Sample CumulatiVe Retainea: Cumulative Pass 1.ng Size-Inches % 0 o/o and Mesh WL % Sul- Wt. % Sul Wt. % Sul- ~ Passing - Retained o/o Ash fur Ofo Ash fur Ofo Ash fur 1-1/2 11 3/ , L L ' /4 11 3/ , /811 20M M 48M L M loom loom N -

36 5. 22 Table IV Washability Data on Minus 1-1 I 2 Inch Size Fractions of Original Coal Sample Cumuladve Fioat Cumulative Sink Specific o/o o/o o/o Gravity Wt. % Sul- Wt. o/o Sul- Wt. o/o Sul- Sink-Float o/o Ash fur o/o Ash fur o/o Ash fur l-l/2 11 x.3/ lo/o l /4" X 3/ o/o /8 11 X 2.0M o/o 'i ,09 99' M X. 48M o/o L L ss M X. loom- 3. Oo/o '"T."" L l ~ loom X. 0 1o/o , '> Composite l-l/2"x o/o l

37 23 Table V Per Cent Sulfur Liberation in Various Sizes Smaller Than 1-1/2 Inches in the Original Coal Samples Size Range 1-1/2 11 X. 3/4 II 3/4 11 X. 3/8 11 3/8" x. 20M 20 x. 48M 48 x. loom loom x. 0 Wt. o/o 2.9l> Sinl<: PrCit. o/o Sulfur Wt. % %Sulfur o/o Sulfur Liberation l-l/2"x

38 24 Figure 9 Theoretical Flowsheet for Cleaning Minus 1-1 /2 Inch Original Coal Sample at Specific Gravities of and (Basis: 100 tons Original Coal). 100 tons original coal 15. O% ash 2. 50% sulfur \~ Cleaned at specific gravity L 40 J Cleaned at specific gravity \~ Clean Coal tons 6. 5% ash ~ Refuse tons 40. 3% ash 1. 55% sulfur 5. 33% sulfur % of s ulfur rejected ~ Clean Coal 86.2 tons 8. 2% ash ~ Refuse tons 57. 4% ash 1. 76% sulfur 7. 12% sulfur 39.26% of sulfur rejected

39 25 Procedure Crusher Tests The pilot plant crushing tests with the 4 11 x 1-1/2 11 size coal listed previously were conducted in the Laboratories of the Pennsylvania Crusher Division of the Bath Iron Works Corporation at West Chester, Pennsylvania, and in the laboratories of the Kennedy Van Saun Manufacturing and Engineering Corporation at Danville., Pennsylvania" Tests were made with the toothed single roll crusher, the jaw crusher, the impactor, coalpactor, and granulator crushers described previously in the Pennsylvania Crusher Laboratory, and tests with the gyratory and cuber crushers were made in the Kennedy Van Saun Laboratory" The tests were made with the 6.5 to 70 pound fractions of the coal after the adjustments were made to the crushers to produce, as nearly as possible, a product which contained 100 per cent of its particles smaller than 1-1/2 inches and the minimum amount of particles smaller than 100 mesh. All products from the mdividual tests were then transported to the Mineral Preparation laboratories at The Pennsylvania State Un1versity for further investigation" Screen Analysis The products from the crusher tests were screened at 1-1/2 11, 3/4 11, 3/8 11, 20 mesh, and 48 mesh on an x 18 11

40 26 Ty-lab tester. All screens plus 20 mesh were round hole. The minus 20 mesh size fractions were rescreened using 8 inch diameter Tyler screens with the 100 mesh screen added. The 20 and 48 mesh screens were used to detect any leakage that might have occurred when using the larger screens. The 3/8 11 x. 20 mesh, the 20 x 48 mesh, and the 48 x 100 m~sh size fractions were then wet screened to remove any adhering 100 mesh x. 0 material. All size fractions were then dried and weighed and the results calculated on a percentage basis. Washability Tests The 1-1/2" x. 3/4 11 and the 3/4 11 x. 3/8 11 size fractions were tested by using a three gallon container filled with organic liquid I of the desired specific gravity ( 1. 4~, 1. 60, and 2. 96). Standard commercial procedures were followed. The 3/8 11 x.20mesh, 20x48mesh, andthe48x.l00rnesh size fractions were tested in specially constructed vessels illustrated in Figure 10. These vessels consisted of a 2000 ml. Erlenmeyer flask with a 71/60 SF ground glass joint and a 2500 ml. funnel with a 71/60 SM grour;:d glass joint. In use, the funnel was placed in the flask and filled with an organic liquid having the desired specific gravity. The flask was charged with the size fraction being tested and alternately stirred and permitted to stratify to prevent the entrapment of misplaced particles. After the separation was complete,, a rubber stopper attached to a rn:!tal

41 27 SPECIAL SEPARATORY VESSELS USED FOR WASHABILITY STUDIES WITH THE 3/8 INCH x 20 MESH, 20 x 48 MESH, AND 48 x 100 MESH SIZE FRACTIONS Figure 10

42 28 rod was twisted through the float material and lodged in the neck of the funnel. The flasks were then separated and the float and sink products were filtered, dried, weighed, and prepared for analysis. The weights of all fractions were then calculated on a percentage basis. The minus 100 mesh size fractions were placed in heavy liquids in the specially ro nstructed centrifuge tubes illustrated in Figure 11. These tubes were constructed from a 4-1 I 2 inch length of Tygon tubing with a 7 I 16 inch bore. A brass plug was wired into the tube at the bottom. After the liquid and coal were placed in the tubes they were centrifuged for 20 minutes at, 4000 RPM. A Hoffman clamp was used to separate the float and sink products which were then removed, dried, weighed, and prepared for chemical analysis. Chemical Analyses These analyses were made on all sizes and on all specific gravity fractions in each size. They consisted of a moisture analysis so that all results could be reported on a dry basis and an ash and sulfur analysis. The standard procedures as outlined by the American Society for 'Thsting Materials for the analyses of coal and coke (271-48) were used for all analyses with but one exception. This exception was con.cerne d with the sink specific gravity fraction in all sizes. It was necessary because of the relatively high percentage of sulfur.

43 ;I I. :.,. 29

44 30 The modification of the standard ASTM procedure consisted in using a smaller sample of material to be analyzed and a larger amount of barium to precipitate the sulfur and barium sulfate. This was necessary in order to maintain the proper barium to sulfur ratio for complete precipitation. Results The screen analysis of the minus 1-1/2 inch product from each crusher test at the conditions used is presented in Tables VI to XVII inclusive, Also presented in these tables are the ash and sulfur analyses for each size fraction. from each product. Calculations of the cumulative weight per cent, the per cent ash, and the per cent sulfur on the retained and passing material for each product are also given in the tables,

45 Table \ri Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Single Roll Crusher Using )/4 Inch Set Gi.irrniTatfve-R.eta1nea-- Cumulative Pas sing Size Inches % 0 and Mesh WL o/o Sul- WL o/o Sul- Wt. % Sul- Pass o/o Ash fur % Ash fur 11/o Ash fur l-1/2" 3/4" L <2 11. l /4 11 3/ l. 48 3/8" 20M l M 48M l l M loom loom VJ...

46 Table VII Screen d.nd Chemical AEaly se s of Minus 1-1/2 Inch Product from Single Roll Crusher Using a 7/16 Inch Set Cumulative Cumulative Retainea Passing Size-Inches o/o 0 0 and Mesh Wt. o/o Sul- Wt. o/o Sul- Wt. % Sul- Passing - Retained o/o Ash fur o/o Ash fur o/o Ash fur 1-1/2 11 3/4'' L /4 11 3/ / M M 48M M loom L loom w N

47 Table VIII Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Jaw Crusher Using a 1 Inch Set c umuiative -Refainea-- Cumulative--Pas-s-ing Size-Inches o/o --- % 0 and Mesh WL % Sul- WL o/o Sul- Wt. % Sul- Pass in~ - Retained % Ash fur % Ash fur % Ash fur 1-1/2" 3/4" l l l. 41 3/4 11 3/ l l. 50 3/ M l l l M 48M l l M loom l l loom l w

48 Table IX Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Jaw Crusher Using a 1/2 Inch Set Cumulative Retained C urn ula tivefa s sing Size-Inches o/o,0,0 and Mesh WL o/o Sul- WL o/o Sul- WL o/o Sul- Passing ~Retained o/o Ash fur o/o Ash fur o/o Ash fur 1-1/2 11 3/ /4 11 3/ l /8'' 20M g M 48M M loom loom VJ ~

49 Table X Screen and Chemical Analyses of Minus I I /2 Product from ratory Crusher Using a 5/8 Inch Set Cumulative Cumulative Retained Passing Size ~ Inches o/o 0 0 and Mesh WL o/o Sui- WL o/o Sui- Wt. o/o Sui- Passing - Retained o/o Ash fur % Ash fur % Ash fur 1-1/2 11 3/4 11 l6a ll I. 57 3/4 11 3/ L I. 60 3/811 20M l I I M 48M I I 9.6 I. 55 II I M loom l I I loom I II w U1

50 Table XI Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Gyratory Crusher Using a 7/8 Inch Set c t.irnuia-t1ver.-etaine d Cumulative PasSl.ng Size~Inches o/o o/o.0 and l'vfesh WL o/o Sul- WL o/o Sul- WL o/o Sul~.Passing -Retained o/o Ash fur o/o Ash fur o/o Ash fur 1-1/2 11 3/ L L l. 56 3/4 11 3/ l, L L 66 3/8" 20M l L l M 48M l, ll 0 l ll. 7 l M loom ll. 5 l loom ll. 6 l w 0' 5

51 Table XII Screen and Chemical Analyses of Minus 1-1 /2 Inch Product from Impactor Crusher Operating at 300 RPM Cumulative Pas Cumulative Retaineu sing Size -lnche s o/o o/o 0 and Mesh Wt. o/o Sul~ Wt. o/o Sul- Wt. o/o Sul- Pas sing - Retained o/o Ash fur o/o Ash fur o/o Ash fur 1-1/2 11 3/ /4 11 3/8" / M M 48M M loom loom l.n --.1

52 Table XIII Screen and Chemical Analyses of Minus 1-12 Inch Product from Impactor Crusher Operating at 500 RPM Cum ula ti ve Pas c umulativeretained sing Size-Inches % 0 0 and Mesh WL % Sul~ WL % Sul- Wt. % Sul- Pas sing - Retained % Ash fur % Ash fur % Ash fur 1-1/2" 3/4'' L L L 64 3/4 11 3/ , L L L 68 3/ M L L L 80 20M 48M L L l M loom L l loom L VJ 00 l

53 Table XIV Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Coalpactor Crusher Operating at 720 RPM Cum-ulative Retained C umulafive-pa s sl.ng Size~ Inches o/o 0 0 and Mesh Wt. % Sul~ Wt. % Sul- Wt. % Sul- Passing - Retained % Ash fur % Ash fur % Ash fur 1-1/2 11 3/4" L 39 3/4'' 3/ L L L 41 3/8" 20M L L 47 20M 48M L M loom L loom L VJ ~

54 Table XV Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Cuber Crusher Operating at 680 RPM Cumu1at1ve IfeFairiea- Ci.irnulafive_P_ass1ng Size-Inches fur %.0 0 and Mesh WL o/o Sul - Wt. % Sul- WL % Sul- Passing Retained % Ash fur o/o Ash fur % Ash 1-1/2 11 3/ /4 11 3/ L 57 3/ M l l M 48M l l M loom l loom l ,.;:,.. 0

55 Table XVI Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Cuber Crusher Operating at 1050 RPM Cumulative Cumulative Retained Passing Size Inches o/o 0 0 and Mesh Wt. % Sul- Wt. % Sul- Wt. % Sul- Passing - Retained % Ash fur % Ash fur % Ash fur 1-1/2 11 3/ /4 11 3/8'' / M M 48M M loom loom ,j:l....

56 Table XVII Screen and Chemical Analyses of Minus 1-1/2 Inch Product from Granulator Crusher Operating at 600 RPM Cum-u]atfve- Re-tainea--- Cum-Ulafive- Passing Size-Inches o/o 0 0 and Mesh Wt. o/o Sul- Wt. o/o Sill- Wt. o/o Sul- Passing ~ Retained o/o Ash fur o/o Ash fur o/o Ash fur 1-1/2 11 3/ /4 11 3/ / M M 48M M loom loom ~ N

57 43 Washability data on each size of each product from each of the crusher tests is presented in Tables XVIII to XXIX inclusive. The washability data includes the weight per cent, the per cent ash, and the per cm t sulfur in each specific gravity fraction. Also persented in the tables are calculations showing the cumulative float and sink values for all individual sizes and composite data for the l-l/2" x 0 material from each test. Tables XXX to XLI inclusive show the per cent sulfur liberation in each size from the products of each test. These data are based upon the amount of sulfur in the specific gravity sink fractions. Calculations on the amount of sulfur liberation in the complete minus l-l/2 inch material in each case are also presented in the tables. Theoretical flowsheets showing the quantity and quality of the clean. coal and refuse products that are possible from each crusher product when cleaning at specific gravities of and are presented in Figures 12 to 23 inclusive. These figures also show the percentage of the sulfur present in the crushed product that would be rejected in the refuse if the cleaning occurred at the above gravities.

58 Table XVIII Washability Data on Minus 1-1 I 2 Inch Size Fractions in Product fror:n Single Roll Crusher with a 3 I 4 Inch Set 44 Cumulative Float Cumulative Sink Specific o/o 0 0 Gravity Wt. % Sul- Wt. % Su1- WL % Su1- Sink-Float % Ash fur % Ash fur % Ash fur 1-112" X % X % " x. 20M % L o g l L x: 48M % , X loom % I g 7.59 I , MxO O,go/o Composite 1-1 I 2" x. o Oo/o I

59 4.5 Table XIX Washabihty Data on Minus 1-1/2 Inch Size Fractions m Product from Single Roll Crusher with a 7/16 Inch Set Cumulative Float Cumuladve Sink Specific o/o 0,0 Gravity WL o/o Sul- Wt. o/o Sul- Wt. o/o Sul- Sink-Float o/o Ash fur % Ash fur % Ash fur 1-1/2 11 X 3/ /o L L /4 11 X 3/ o/o l l L /8 II X. 20M o/o ,, LOS 100, l Zl q.~. 2 b. S l ')7, S q.o" l x. 48M % l '"':84" ~ l ~ , , L L l.o ioo.o 8.6 l X. loom. l. 4% Kl L ax.. / ~' '± :3 L loom ls % lao 68. l 2. 7 \f:6q l l':l Composite l-1/2 11 xo % l l L ~ l ' l