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By R. E. Tate, L. J. Herman

We have had occasion to produce wire of Np-237 in small diameters for use in some chemical experiments. Since the mechanical metallurgy of neptunium has not been investigated extensively, it seems desirable to report our successful extrusion technique. Because of the neptunium activity and its attendant health hazard the experimental work was done in glove boxes and related equipment also used for Pu-239. At room temperature a phase neptunium' is a hard (Dph -355) orthorhombic metal of high density (p = 20.45 g per cu cm). a neptunium transforms2 to tetragonal ß neptunium at about 280°C and this in turn transforms to bcc y neptunium at about 577°C. The y phase melts at about 637°C. A temperature of 340° to 345°C was selected for the extrusion, this temperature being a compromise be- tween a possible advantage of working with the presumably more plastic cubic y phase above 577°C and the risk of having the neptunium react with the alloy steel die to form the low-melting Fe-Np eutectic. A 0.75-in.-long, 0.26-in.-diameter ingot of good-purity* Np-237 was extruded by the direct *C = 230 ppm, Pu = 200 ppm, thirty-five metallic elements below limit of detection by spectrographic methods. process through flat-face orifices to form several sizes of wire ranging from 0.010 to 0.030 in. in diameter. Molybdenum disulfide was used as the die lubricant. The extrusion was done in a vacuum of about 10-4 torr to reduce reaction of the neptunium with atmospheric gases. British workers3 at Harwell have extruded neptunium under similar conditions. The force required to extrude 0.010-in.-diameter wire at the rate of 4 in. per min was 6000 lb, as measured with an electrical load cell. Wire 0.020 in. in diameter was extruded with a force of 4700 lb at a rate of 2 in. per min, and wire 0.030 in. in diameter was extruded with a force of 4000 lb at a rate of 1.3 in. per min. An extrusion constant, c, can be computed from the measured forces, P, for the equation4 P = c log-A/a where A/a is the extrusion ratio or the ratio of the cross-sectional areas of the container and the

Jan 1, 1965

Organization Place Date 1917 American Electrochemical Society Pittsburgh, Pa. Oct. 3-6 American Institute of Mining Engineers St. Louis, MO. Oct. 8-13 American Gas Institute : Washington, D. C. Oct. 16-19 American Institute of Architects Philadelphia, Pa. _ Dec.. 26-29 American Society of Mechanical Engineers New York City. Dec. 26-29 American Mining. Congress State Chapter Phoenix, Ariz. Dec. 26-29

Jan 10, 1917

This consolidated index covers all publications of the Institute for the years 1926 through 1935. The following list indicates subjects of volumes and gives numbers or abbreviations used to designate them. TRANSACTIONS VOLUME *G26. Petroleum Development and Technology in 1925 (Published in 1926). *G26. Petroleum Development and Technology in 1926. *E27. Institute of Metals Proceedings. 73. Nonferrous Metallurgy, Milling and Concentration, Nonmetallic Minerals, Institute of Metals and Iron and Steel. [ ]

Jan 1, 1936

By George M. Fowler

EVERY year it becomes more difficult to find new mining districts and new ore deposits. Nearly all of the important discoveries so far can be attributed to surface manifestations overlying the ore deposit. In the future greater skill will be necessary to find ore deposits that give little or no indication of their presence. Mining geology is making progress by broadening its attack upon mineralized regions, by including in its investigations studies of the relation of physical-chemical processes to ore precipitation and various phenomena that heretofore have not always been looked upon as major factors in the problems. Such, for example, are petrographic peculiarities that will help determine structure, aspects of strata or formations favorable or unfavorable to structural deformation or mineralization, and renewed studies of chert and dolomite. This broadening attack is not necessarily being directed to the study of large areas, but rather by doing extremely detailed work in three dimensions in relatively small critical areas to find the key to the structure, reasons for the manner of rock deformation, composition and texture of the rock, and other con¬trolling factors in the larger areas.

Jan 1, 1935

[AARONSON, E.: Discussion on Recent Developments in Fractionation as Applied to Tube Still Distillation, G26, 418 Abbe. See Microscope. Abbe apertometer, 95, 16 ABBOTT, W. L.: A.S.M.E. president, M26,113 biography, M26,113 ABORN, R. H.: Discussions: on Effects of Columbium in Chromium-nickel Steels 113, 159 on Pure Iron and Allotropic Transformations 84, 342 on Prevention of Intergranular Corrosion, 100,329 ABORN, R. H. AND BAIN, E. C.: Discussion on Widmanstätten Structure in Ironcarbon Alloys 105, 252]

Jan 1, 1936

By J. S. UNGER

A LARGE proportion of the coke used is made in the by-product oven from the high-volatile coals mined in the adjacent district. At the beginning it was feared good by-product blast-furnace coke could not be made with our coals. By experimenting with various mixtures of coals, coking time, oven design, and coking temperatures, much has already been accomplished. The results show that a hard, dense coke, not easily broken by handling, can be produced. In its present state it is not all that could be desired, but it is being constantly improved. Such coke has been used alone as the fuel on several of the blast furnaces producing the highest daily production in the Pittsburgh district. Many of the coals in the Pittsburgh district when coked in the by-product oven yield a gas which contains a high percentage of sulfur, which is objection- able for many metallurgical operations. As this fuel is gradually replacing the ideal fuel, natural gas, which is becoming less plentiful, studies are being made of the best methods for purification. Some metallurgists believe sulfur to be a very injurious element in steel. Recent investigations by Government bureaus, scientific bodies and private firms, seem to indicate that a reasonable amount of sulfur may exist in steel without detriment. Without wishing to provoke any metallurgical controversy on the subject of sulfur, the fact remains that the daily purification

Jan 1, 1926

[JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington) D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists 11 Broadway New York 4, N. Y. BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 210 La Arcada Bldg. Santa Barbara, Calif. COWIN & CO. Mining Engineers and Contractors Consulting Shaft & Slope Sinking Appraisal Mine Development Reports Mine Plant Construction I- 18th St. S. W. B'ham, Ala., Phone 56-5566]

Jan 1, 1952

Jan 1, 1885

By S. S. Hsieh, J. R. Lehr

Bench scale beneficiation studies were made on Idaho dolomitic phosphate rock using the TVA carbonate flotation process. The process used diphosphonic acid as a phosphate mineral depressant and fatty acid as a carbonate mineral collector. Silica was subsequently rejected as float using an amine collector, with phosphate product recovered as the sink fraction. Two samples of prepared flotation feed from commercial operation were used. One contained 21% P205 and 3.2% MgO. The other contained 26% P205 and 1.8% MgO. The results indicate that concentrates containing 31% to 33% P205 and 1% or less MgO can be obtained, with about 80% P205 recovery.

Jan 1, 1986

By R. C. FLEMING

MINING rock asphalt for use as a paving material is an industry which has grown with the spread of the good roads movement. "Mineral Industry During 1930" reports asphaltic pavements constructed, including maintenance and repair but excluding pavement constructed with road-oil, cut-back or emulsified asphalt, as grown from 23 million square yards in 1911 to a high of 144 million in 1927. In 1930 the same source reports 106 million square yards of such paving laid and, in that year, 664,871 tons of native rock asphalt were so utilized. Many states contain rock asphalt deposits of greater or less importance but in only a few places are the de¬posits being mined commercially. In the year cited Ken¬tucky produced 305,024 tons of bituminous sandstone, Texas 270,138 tons, mostly bituminous limestone, while Alabama, Oklahoma, California and Utah produced 89,709 tons of bituminous rock for road construction. In addition Utah produced 37,906 tons of the purer asphaltic products, gilsonite, wurtzilite and ozokerite, for other uses. Speaking generally, the rock asphalt is a sandstone or limestone naturally impregnated with asphalt to an extent that makes it an ideal road surfacing material without mixing or treatment other than crushing. The asphalt content of the commercial product runs 8 to 12 per cent.

Jan 1, 1933

By H. F. Moore

DURING the last six years, there have been many extensive investigations of the fatigue of metals. The major work of 'these investigations has been the determination of constants for fatigue strength of wrought ferrous metals; but during the past year or two there have become available considerable test data on the fatigue strength of certain nonrferrous metals, including copper, brass, bronze, nickel, copper-nickel alloys, aluminum and aluminum alloys, magnesium and magnesium alloys. It is not proposed to give here extensive quantitative tables of test results; for such tables, reference is made to the published data of various laboratories. The following general conclusions, however, seem to be fairly well established: 1. The phenomenon known as "fatigue" of metal really a progressive fracture of metals. A minute (probably submicroscopic) crack is formed in the metal, the internat stress, is intensified at the ends' of the crack, and under successive applications of load the crack spreads like a minute hacksaw cut until there is not enough sound metal left in the cross-section of the piece to stand the load. applied, and then failure occurs suddenly. 2. For wrought ferrous metals, there is .a limiting intensity of stress (as computed by the ordinary formulas of mechanics of materials) below which, a metal is able to withstand an indefinitely large number of repetitions of stress without failure. This limiting stress is known as the "endurance limit or the fatigue limit.? For reversed flexure, the endurance limit for. wrought ferrous metals is usually not far from 50 per cent. of the ultimate tensile strength.

Jan 1, 1925

On the Art of Metallography (Howe Memorial Lecture), by F. F. Lucas; Beneficiation of Iron Ore. Abstract of paper by C. E. Williams followed by Round Table Discussion; A Statistical Analysis of Blast-furnace Data, by R. 8. McCaffery and R. G. Stephenson; Air Discharge of Circular Tuyeres, by R. S. McCaffery and D. E. Krause; Open-hearth Steel Process as a Problem in Chemical Kinetics. by E. R. Jette; Carbon-oxygen Equilibrium in Liquid Iron, by H. C. Vacher and E. H. Hamilton; A Thermodynamic Study of the Phasial Equilibria in the Bystem Iron-carbon (Abstract), by Yap, Chu-Phay; Influence of Dissolved Carbide on the Equilibria of the System Iron-carbon (Abstract), by Yap, Chu-Phay; Inclusions and Their Effect on Impact Strength of Steel, I and 11, by A. B. Kinzel and W. Crafts: Method for Electrolytic Extraction of MnO, MnS, FeS and Si02, Inclusions from Plain Carbon Steels, by G. R. Fitterer; Permanent Growth of Gray Cast Iron, by W. E. Remmers; Some Notes on Blue Brittleness, by L. R. van Wert; Austenite-pearlite Transformation and the Transition Constituents, by A. Sauveur; Age-hardening of Austenite, by F. R. Hensel; Transformational Characteristics of Iron-manganese Alloys, by H. Scott; Composition Limits of the Alpha-gamma Loop in the Iron-tungsten System, by W. P. Sykes; Magnetic Properties Versus AUotropic Transformations of Iron Alloys, by T. D. Yensen and N. A. Ziegler; Dilatometric Study of Chrome-nickel-iron Alloys, by V. N. Krivobok and M. Gensamer; Low-carbon Steel, by H. B. Pulsifer; Bright Annealing of Steels in Hydrogen, by F. C. KeUey; Development of Continuous Gas Carburieing, by R. J. Cowan. Transactions, Institute of Metals Division, 1931. 500 pages. Index. Papers and discussions presented before the Division at Chicago, Sept. 22-26, 1930 and New York, Feb. 16-19, 1931. X-ray MetallograpIhy: X-ray Determination of Alloy Equilibrium Diagrams (Annual Lecture), by A. F. Westgren; Suppressed Constitutional Changes in Alloys. by G. Sachs; Texture of Metals after Cold Deformation; by F. Wever. Theoretical Metallurgy: Studies upon the Widmanatitten Structure. I.—Introduction. The Aluminum-eilver System and the Copper-silicon System; by R. F. Mehl and C. S. Barrett; Studies upon the Widmanstatten Structure, 11.—The Beta Copper-einc Alloys and the Beta Copper-alumnum Alloys, by R. F. Mehl and 0. T. Mareke; Application of X-rays in the Manufacture of Telephone Apparatus, by M. Baeyerts; Thermal Conductivity of Copper Alloys. 11.—Copper-tin Alloys; 111.—Copper-phosphorus Alloys, by Cyril Stanley Smith; Thermodynamic Study of the Equilibria of the Systems Antimony-bismuth and Antimony-lead, by Yap, Chu-Phay. Ganeral: Cemented Tungsten Carbide; a Study of the Action of the Cementing Material, by L. L. Wyman and F. C. Kelley; Influence of Casting Practice on Physical Properties of Die Castings, by C. Pack; Fabrication of the Platinum Metals, by C. S. Sivil; Effect of Certain Alloying Elements on Structure and Hardness of Aluminum Bronze, by 9. F. Hermann and F. T. Sisco. The WorkinG oF Metals: Metal Working in Power Presses, by E. V. Crane; Forming Properties of Thin Sheets of Some Nonferrous Metals, by W. A. Straw, M. D. Helfrick and C. R. Fischrupp; Die Pressing of Braas and Copper Alloys, by J. R. Freeman. Jr.; Plasticity of Copper-sina Alloys at Elevated Temperatures. by A. Morris: Directional Properties in Cold-rolled and Annealed Copper, by A. Phillips and E. 9. Bunn; Effect of Combinations of Strain and Heat Treatment on Properties of Some Age-hardening Copper Alloys by W. C. Ellis and E. E. Schumacher; Constituents of Aluminum-iron-silicon Alloys, by W, L. Fink and K. R. Van Horn; Equilibrium Relations in Aluminum-antimony Alloys of High Purity, by E. H. Dix, Jr., F. KeUer and L. A. Willey; Equilibrium Relations in Aluminum-magnesium Silicide Alloys of High Purity, by E. H. Dix. Jr., F. Keller and R. W. Graham; Constitution of High-purity Aluminum-titanium Alloys, by W. L. Fink, K. R. Van Horn and P. M. Budge; Experiments on Retarding the Age-hardening of Duralumin, by E. H. Dix. Jr. and F. KeUer; Aluminum-silicon-magnesium Casting Alloys, by R. S. Archer and L. W. Kempf; Modulurr of Elasticity of Aluminum Alloys, by R. L. Templin and D. A. Paul; Quenching of Alclad Sheet in Oil, by H. C. Knerr.

Jan 1, 1931

By J. R. Campbell

THE need for standardizing methods of arriving at definite conclusions regarding the cleanability of a given coal, and for measuring the performance of coal-cleaning equipment, is constantly increasing. Earlier notes by the author on this subject are amplified in this paper, because he believes that better preparation of bituminous coal is a partial solution of the coal operators' troubles. WASHABILITY STUDIES The term "washability" of coal was coined when washing was the universal method of separating coal from its impurities by utilizing their difference in specific gravity. This and analogous terms are still used in their broad sense although pneumatic or air separation is now used to clean coal. These terms are so used in this paper. Too much time or money, can hardly be spent on "feed surveys" to get a "picture" of the coal that is to be cleaned. There have been too many "rule of thumb" methods used. Screen analyses and "sink-and-float" tests on the raw coal enable the coal operator and washery man to predict within reasonable limits the results that may be expected from any efficient cleaning apparatus.

Jan 1, 1928

By P. E. Fitzgerald, J. C. Gindlesperger

1. The Acidizer (Trade Publication of Dowell Inc.): No. 1. Aspects of Acidizing. No. 2. Inhibited Acid. No. 3. The Value of Acidizing. No. 4. The Chemistry of Acidizing. No. 5. Jelly Seal in Acidizing. No. 6. Loosening Stuck Drill Pipe. No. 7. The Geology of Acidizing. 2. J. C. Albright: Acid Is Being Used for Cleaning Intake Wells in Water-flooded Areas. Oil Weekly (Sept. 23, 1935) 24. 3. D. H. Bancroft: Acid Tests Increase Production of Zwolle Wells, Miller County, Arkansas. Oil and Gas Jnl. (Dec. 22, 1932) 42. 4. A. H. Bell: Possible Areas for Acid Treatment in Illinois. Pub. of Illinois- Indiana Petr. Assn. and lllinois Geol. Survey (1934) 49. 5. N. A. Best: Treating Limestone Formations Consists of More than Pouring Hydrochloric Acid in the Well. Oil and Gas Jnl. (April 5, 1934) 54. 6. L. G. E. Bignell: Sealing Off Salt Water from Oil-bearing Formations. Oil and Gas Jnl. (Jan. 30, 1936) 59. 7. L. G. E, Bignell: Acidizing Upper Limestone Formation Facilitated by the Use of Jelly Seal. Oil and Gas Jnl. (March 5, 1936) 30. 8. L. G. E. Bignell: Bailing, Shooting, Tubing and Acidizing Have All Been Tried in Deep Test at Binger, Oklahoma. Oil and Gas Jnl. (May 10, 1934) 38. 9. L. G. E. Bignell: Dowel1 Incorporated Increasing Its Field Service for Acid Treatment of Wells. Oil and Gas Jnl. (June 7, 1934) 62. 10. L. C. Chamberlain, Jr. and P. E. Fitzgerald: Oil Well Acidizing in Michigan. Mich. Acad. Sci. Papers (March 1937). 11. M. E. Chapman: Some of the Theoretical and Practical Aspects of the Acid Treatment of Limestone Wells. Oil and Gas Jnl. (Oct. 12, 1933) 10. 12. C. E. Clason and J. G. Staudt: Limestone Reservoir Rocks of Kansas React Favorably to Acid Treatment. Oil and Gas Jnl. (April 25, 1935) 53. 13. W. F. Cloud: Cleaning and Reconditioning Oil Wells—Reconditioning by Use of Acid (Petroleum Production 1937), 389. University of Oklahoma Press, 1937,' 14. K. A. Covell: Developments in Eastern Production Practice. Acid Treatment of Michigan Wells. Amer. Petr. Inst. Prod. Bull. 213 (1934) 77; Oil and Gas Jnl. (May 31, 1934) 89; Oil Weekly (May 28, 1934) 17. 15. B. A. Cunningham: Acid Treatment of Lime Formations. Amer. Petr. Inst. Paper 901 (1933) 9D, 1-7. 16. 0. I. DeSchon: Pondera Production up 22,000 Barrels. Montana Oil & Min. Jnl. (Jan. 26, 1935) 1.

Jan 1, 1937

By W. F. Boericke

WORLD production of silver in 1929 totaled 256 million ounces. In 1928 production was 258 million ounces, and in 1927, 254 million ounces. With an actual decrease in the amount of silver produced last year, as compared with 1928, and an increase over 1927 of less than one per cent, obviously there has been no overproduction of the metal in the popular sense. But the price of silver tells a different story. For 1927, the average quotation was 56.37 cents; it was 58.17 in 1928, and 53.0 in 1929. During the last year it reached a high point of 57 cents in January, and fell steadily, without interruption to the downward trend, to a low of 47 cents in December. Since then it has dropped to an all time low of 43 cents on February 6.

Jan 1, 1930

By I. R. Kramer

I. R. Kramer (Martin Co.)—In a recent paper Nakada and Chalmers24 reported some observations of effects of surface conditions on the stress-strain curves of aluminum and gold single crystals. It is of interest to compare these observations with the results published previously in this journal and to comment on their general conclusions. In brief, Nakada and Chalmers concluded that the removal of the surface layer of a prestrained specimen lowered the stress-strain curve for aluminum but not that for gold. Further, they concluded that the surface work hardening of aluminum is confined to a depth not more than l0-3 cm. In our results25 published previously, it was pointed out that when prestrained specimens of aluminum and gold were polished to reduce the thickness upon reloading the initial flow stress decreased markedly. Further if a sufficient amount of metal was removed, the yield point failed to appear. With continued application of the load the stress-strain curve became coincident with that of the virgin crystal. We have found this behavior in some 100 determinations to hold consistently for gold, aluminum, and copper in both single and poly-crystalline specimens. The amount of strain required before the curves coincided depends upon the amount of metal removed but it is usually less than 0.01. This type of behavior is the same as that reported for metarecovery by other investigators.29 For aluminum specimens which have been prestrained and then heated to temperatures above 50°C we have consistently found that the stress-strain curve was typical of the orthorecovery28 type. In this case the stress-strain curve always lies below that of the virgin specimen. With respect to Ref. 24 the curves for aluminum are always below that of the virgin curves, while those for gold become coincident. This observation indicates at least for aluminum that the specimens must have been heated to a temperature high enough to cause recovery by an alteration of the internal dislocations. In addition, a recovery would be expected because of the removal of the surface work-hardened layer. Nakada27 had reported that, with his particular apparatus in which a perchloric acid polishing solution was used, the temperature of the specimen increased 65°C. The curves presented in Ref. 24 for gold do not permit one to detect the initial flow stress upon reloading after the surface-removal treatment. In fact, contrary to the method used by Nakada and Chalmers, the change in the stress-strain curve produced by a surface-removal treatment cannot be described in terms of a decrease in stress at strains much higher than that at the initial flow stress because of the coincidence of the curves at the higher strain values. With regard to the depth of the work-hardened surface layer, our data show for aluminum single crystals (7.5 by 0.3 by 0.3 cm) that the initial flow stress remained constant after 12 x 10-3 cm had been removed from the thickness. This depth was independent of the prior strain. For gold crystals this depth is somewhere between 10 x 10-3 and 20 x 10-3 cm. Y. Nakada (author's reply)— Kramer states,28 "for aluminum specimens which have been prestrained and then heated to temperatures above 50°C, we have consistently found that the stress-strain curve was typical of the orthorecovery28 type. In this case the stress-strain curve always lies below that of the virgin specimen." However, Cherian et a1.26 discovered that aluminum polycrystals annealed at 32" and 100°C showed the metarecovery behavior. They showed that the orthorecovery behavior did not appear until the crystals were annealed at 150°C. Kramer suggests28 that the drop in the flow stress of aluminum crystals after the surface removal by electropolishing24 may be due to the recovery caused by the temperature rise which may occur during the electropolishing.27 However, as indirectly stated in Ref. 24, the current density used in these electro -polishing experiments was 0.15 amp per sq cm. According to ref. 27, this current density should cause a temperature rise of only 40°C. This may cause the metarecovery but not the orthorecovery. Furthermore, as stated explicitly in Ref. 24, the surface removal was accomplished by chemical etching as well as by electropolishing. The results were the same for both electropolishing and etching. During the etching, the specimen temperature did not rise above 35°C. Some aluminum crystals were placed in water at 35° C for 30 min. These crystals did not show the decrease in flow stress. Therefore, it is quite clear that the flow-stress drop after the surface removal is not caused by a high-temperature recovery. However, as Kramer points out,28 it is quite possible that the internal dislocation structure may have been altered because of the removal of the highly work-hardened surface layer. However, how much this rearrangement contributes toward the flow-stress decrease is not known at present.

Jan 1, 1965

By Charles E. Locke

CONTINUED expansion of gold mining in 1935 led to further developments in treatment methods. In base metals and non-metallics progress is also noted, coincident with greater activity. Statistics are not available yet for 1935 but the trend is shown by 1934 when nonferrous ore mined in the United States was 35,840,737 tons, or 45 per cent more than in 1933. The amount concentrated was 27,167,530 tons or 75.80 per cent of the ore mined, and flotation was used in whole or part on over 96 per cent of the ore subjected to concentration. In the crushing field a new model of the Fahrenwald crusher is promised soon. The Symons fine-reduction cone crusher and Traylor secondary crusher continue to gain as intermediate crushers. A new book entitled "Crushers for Stone and Ore" by William T. W. Miller appeared. The Hadsel mill has been improved still further and a number of installations are in satisfactory operation showing economical power consumption and low wear. An attempt in a

Jan 1, 1936

THE solid nonmetallic inclusions present to some extent in all commercial steels have been variously designated. In early references they were usually called slag inclusions, and this terminology is still retained to some extent. On the premise that all nonmetallic matter produced in a metallurgical process is slag, this can be justified. We have come to think of slag, how- ever, in a more restricted sense, and calling these particles slag inclusions is further objectionable because it fosters the erroneous concept that they are actually incorporated portions of furnace slag. Rarely is this true. The term sonims (coined from solid nonmetallic impurities) was proposed many years ago but never came into common use. In general, the term non- metallic inclusions seems to be satisfactory and adequate. NATURE AND CONSTITUTION OF NONMETALLIC INCLUSIONS From the standpoint of origin, inclusions fall naturally into two classes: (1) those occurring as a result of reactions taking place in the body of molten or solidifying metal and (2) those resulting from mechanical incorporation of refractories or other materials with which molten steel comes in contact. The former are by far the more numerous and have been called indigenous, natural, or native inclusions. The latter are by their very nature sporadic in occurrence and have been called exogenous, accidental, adventitious, or foreign inclusions. They are often referred to as the "slag-stringer" type, though here also the material is not likely to be furnace slag. Substances Found in Inclusions. Nonmetallic inclusions are composed principally of oxides and sulfides but carbides and nitrides sometimes play an important role. In the case of indigenous inclusions the reactions by which these particles are precipitated from molten or solidifying steel may be caused by: (1) oxidation such as may occur during refining or during tapping and teeming, (2) deoxidation by added alloys, (3) change

Jan 1, 1951

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman's paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author's comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951

By L. E. Shiffman

W. J. Parton—Those operators faced with the problem of treating fine coal whether in bituminous or anthracite will find this paper most timely. I would like to take this opportunity of discussing Mr. Schiffman's paper and at the same time express certain views relating to our Tamaqua plant. I would like to ask the author what type of impeller and diffuser is used in the Denver cells? Screen analysis of products from individual cells indicate that coarser material resists flotation and only floats after greater retention time in the last few cells. Also, the need for a scavenger screen to reclaim non-floated coal particles further stresses this point. I have always felt that more efficient means of cleaning coal between 10-mesh and 28-mesh existed than flotation. Reagent and power costs are high for the flotation process. When floating +28-mesh particles, cell capacity is lowered and some of the particles are lost with the refuse. The Tamaqua plant of the Lehigh Navigation Coal Co. floats —28-mesh coal and capacity of recoverable coal is 40 tph for 1800 cu ft of Denver cells; or 0.05 tons per cu ft of cell. At Kimberly 7.75 tph for 600 cu ft of cell gives 0.013 ton per cu ft of cell. At Bessie 14 tph for 800 cu ft of cell gives 0.017 tons per cu ft of cell. It would be appreciated if the author would comment on what he feels is the upper size limit of particle to attain most efficient utilization of the flotation process. The dewatering screw is a very interesting development since it offers a simple way to prepare coal sludge for more complete clewatering by drainage or mechanical dewatering on screen or filters. In other words it could be used to accomplish the same thing as a thickener tank. I would appreciate having the author's comment on how he thinks such a screw dewaterer would work on a froth.* The process as used in floating coal at the Bessie and Kimberly plants may be referred to as more of a bulk oil float in contrast to a froth flotation process. Experiments on increasing capacity of cells is most interesting since we are going through such an experi- mental period at the present time. Recently a double overflow was installed on our No. 30 Denver cells. So far results are not conclusive. In reviewing this paper the following comments are made pertaining to investigation of methods for increasing capacity: Supercharging: Supercharged air in matte flotation or for that matter the use of the normal amount of air drawn in by the impeller would in all probability cause such an aeration in the cell as to destroy the buoyant effect given to the coal particles by the excessive amount of kerosine used. In other words, air creates an agitation zone throughout the cell, creating a boiling and thereby giving a lower recovery in the cell. It would be interesting to know whether the 7 pct increase in recovery was with no air being admitted to the stand pipe. Changing Impeller Speed: The speed of a receded disc impeller for a No. 30 cell as recommended by the Denver Equipment Co. is, I believe, approximately 250 rpm. At this speed and using supercharged air in excess of 8-oz pressure, we have observed a boiling action in the cells. In our flotation we endeavor to obtain some degree of froth flotation using pine oil as a frother. The boiling action as caused by increasing the amount of air added to the cells is detrimental to recovery in froth flotation. It is our belief that to obtain increased recovery from a cell in froth flotation, additional air must be introduced but at the same time this air must be dispersed throughout the pulp in the form of small bubbles and this can only be done by increasing the speed of the impeller. Therefore, if Mr. Schiffman decreased the speed of the No. 30 impellers and at the same time continued to use supercharged air, the boiling action may have been increased because larger bubbles developed. The lower recovery as reported could be due to this factor. Decreasing the impeller speed will definitely decrease the power consumed but may have other disadvantages. First, we believe it will permit "sanding" in the cell and this in our opinion will increase the wear on the impeller and diffuser, especially so, if there is pyrite and/or sand present in the feed. "Sanding" in the cell when air is used, as in froth flotation, will effect the dispersion of this air and cause boiling.

Jan 1, 1951