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By AIME AIME

THE CHAIRMAN of the fast growing Petroleum Division is not only a graduate of the University of California, but a third generation native son. After a few years spent in hard-rock geology, his professional efforts were transferred to the sedimentaries and to petroleum investigations, as a consulting geologist. For ten years these investigations covered the Rocky Mountain, Oklahoma, Texas, and eastern districts. After the war he returned to Casper, Wyo., as chief geologist for the Consolidated Royalty Oil and Western Exploration Companies. This employment afforded him the opportunity to study particularly the economic relationship between the lessor-lessee interests in development and production, a somewhat unusual type of petroleum specialization.

Jan 1, 1939

By AIME AIME

NOTWITHSTANDING the metropolitan appearance of M. L. Haider, the present Chairman of the Petroleum Division, he is not a native New Yorker, but was born at Mandan, N. Dak., Oct. 1, 1904. He began his travels at an early stage in life and after attending the University of Southern California for two years he spent two additional years at Stanford University and was graduated in 1927. After a few months as an analytical chemist for the Portland Cement Co. he became research engineer in the natural gasoline department of the Richfield Oil Co. where he remained for approximately two years before taking a position with the Carter Oil Co. in Oklahoma. He was chief engineer for this company for three years before being trans-

Jan 1, 1945

By W. E. C. Coxe

Many of you who are interested in the manufacture of iron and steel, have no doubt heard of the "Wheeler process for combining iron and steel." Mr. Wheeler has formed a company, styled the "Combination Trust Company," whose business is to grant licenses for the use of this patent process in producing what he calls "iron-clad steel." It has been proposed to apply it in the manufacture of car or wagon axles, also to shafting, having steel cores or centres covered with iron; to tubes of steel with an inner and outer skin of iron ; to structural purposes, such as girders and beams; bridge and tie-bolts, where the strength of the iron and the rigidity of the steel would be desirable. In answer to a request from Mr. Wheeler, permission mas accorded him to make some experiments at the rolling mill of the Philadelphia and Reading Coal and Iron Company, at Reading, Pennsylvania, with a view to manufacturing some steel-headed rails. In making this kind of a rail two difficulties are encountered. If the iron is brought to the requisite heat to weld properly, the steel is likely to be burned; if the steel is cared for, to prevent burning, the several layers of iron are not brought up to the proper welding heat. Mr. Wheeler claimed that the steel slab covered with iron which he furnished for the head of the rail could net be injured by any heat to which it might be subjected in the ordinary course of heating the rail-pile. He claimed, also, that by this method the porosity, which he thought was characteristic of all solid rails of Bessemer steel, would be overcome. Four steel slabs were furnished for this experiment, being Bessemer steel of .61 carbon, made at the Edgar Thomson Steel Works, and covered with iron in one of the Pittsburgh mills. The slabs were in section seven inches wide by three inches thick, and the iron covering was one-eighth to three-sixteenths inch thick. Each slab was placed on a pile of iron made up in the ordinary way for a rail fifty-six pounds per yard and thirty feet long. The heating was under the personal direction of Mr. Wheeler, and

Jan 1, 1879

By A. Eilers

A number of the copper refineries in this country have lately separated some of the rarer metals from the slimes in the refinery tanks. One of these has furnished me the following table of recoveries from given amounts of blister. I publish this to show the proportions, to gold and silver and to each other, in which these rarer metals may be expected to occur in copper from certain localities. GarFIeld, Utah :—The blister copper comes principally from the Bingham porphyry copper mines. Steptoe, Nev. :—All the blister copper is produced from the Nevada Consolidated mines. (Also porphyry deposits.) Omaha, Neb. :—Blister copper comes principally from concentrated copper-lead mattes shipped from the different lead-silver plants of the Rocky Mountain region to the converters at the Omaha lead refinery. Mountain, Cal. :—Ores occur in connection with diorite (?).

Jan 1, 1914

By George H. K. Schenck, Peter G. Donald

There is an accelerating acceptance of change by management of cement companies. Diversity of response is noticeable in efforts across the country to reverse the downward trend in profits that brought margins in 1966 to the lowest point in 20 years. New concepts are emerging among managers as they seek to increase the efficiency in use of the basic corporate resources of men, capital and technology. The shift towards computerized control of cement manufacturing is making new gains as is diversification of cement companies into allied fields such as production and sale of natural and light- weight aggregates, crushed stone and concrete products. Increased interest in special products such as white cement and further moves overseas are also significant. Perhaps the most dramatic event of recent years occurred in Washington at hearings before the Federal Trade Commission where cement producers split on whether there should be FTC guidelines that would prevent ownership of ready-mixed concrete producers by cement companies.

Jan 4, 1967

By AIME AIME

HENRY DAYTON WILDE-"Date," informally- manager- of the technical and research department of the Humble Oil & Refining Co., was born at Aguascalientes, Mexico, Sept. 25, 1900. He is a graduate in chemical engineering: M.S. from the University of Texas and I Sc.D. fro111 the Massachusetts Institute of Technology. t For a year and a half in 1926 and 1927 he was a research : associate in the research laboratory of applied chemistry at M.I.T., under W. K. Lewis. In the latter year Dr. Wilde went with the Humble as head of the laboratory experimental division of its refining development department. In 1929 he was made director of production research. Dr. Wilde is the author of important papers in the TRANSACTIONS of the Institute, wherein are also mans dis-

Jan 1, 1938

By Evan Evans

HOME-TOWN boy makes good in a i1 big way in the home ' town, expresses concisely the accomplishments of Evan Evans. Born in Coaldale, Pa., in 1895, within sight of the mine head-frames and cleaning plants dotting the Panther Creek Valley, his whole life has been intimately associated with the strip and underground mines of this valley. One of the world's largest mineral deposits exists in the confines of the Panther Creek Valley and mining has been in progress for 125 years. Despite this long period of mining activity, two thirds of the coal in the valley yet remains to be mined. The Lehigh Navigation Coal Co. is the operating company.

Jan 1, 1947

By J. Kent Smith

THE object of this investigation was to ascertain the effect of varying percentages of beryllium upon pure copper and the properties of the resultant alloys in their softest condition, the effect of heat hardening on them, and the extents to which these properties could be augmented by different combinations of heat hardening and cold rolling. The data compiled in this paper represent partial results of continuing work done by the writer during the years 1930 and 1931, which was a continuation of the unpublished ground work incepted in the laboratory of the Beryllium Corporation of America by H. B. Pulsifer in the year 1926. A short bibliography on beryllium alloys is appended to this paper. It has, of course, long been known that copper subjected to cold work is hardened and strengthened to a considerable extent, furthermore it had been qualitatively noted in previous experiments that copper-beryllium alloys seemed to take on hardness and strength as the result of cold work at a greater rate even than does plain copper. It was decided therefore to endeavor quantitatively to determine such rate of increase, as also the relative increases by combinations of cold working and heat hardening. The results are summarized in Tables 3, 4 and 5. A preliminary series of experiments had indicated that by an exposure to the heat of 575° F. for 2 1/2 hr. age-hardening of a 2.50 per cent beryllium-copper alloy took place. Slab ingots of nine different beryllium-copper alloys were prepared under identical conditions by means of the addition of a previously prepared 12.5 per cent beryllium-copper alloy to well melted and deoxidized pure copper. The ingots were then reduced by hot rolling to 12 gage (about 0.080 in.). These strips were heated to 1450° F. and quenched in cold water, and thus brought to their softest condition. (See Table 1.) Strips were next "precipitation-hardened" by reheating to a definite temperature. Similar strips to those itemized in Table 1 (which had been quenched from 1450° F.) were reheated for varying periods of time at 575° F. The hardness figures show that a metastable condition, of which the range of stability is dependent entirely upon time at the given temperature, begins to be noted in copper samples containing as little as 0.85 per cent beryllium. It is extremely noticeable in samples containing

Jan 1, 1932

By A. H. Grobe, F. N. Rhines

AT elevated temperatures the oxide of silver is unstable in the air at atmospheric pressure, consequently no external oxide scale forms upon pure silver under conditions of high-temperature annealing. When small quantities of certain alloying elements are present in the silver, the formation of a thin external scale is possible' and in addition there may form a subscale composed of the oxide of the solute element precipitated within the body of the silver. Norbury2 and Leroux and Raub3 have reported internal oxidation (subscale forma¬tion) in alloys of silver with 2, 7.5, and 30 per cent of copper. The presence of the subscale is believed to be responsible, at least in part, for the objectionable "fire mark" in Sterling silver.4 Several other alloys of silver, after oxidizing heat-treatments, are known to exhibit undesirable polishing characteristics that may be the result of internal oxidation. Except for the absence of an external scale of silver oxide, it is to be anticipated that silver alloys will prove to be very similar in their oxidation behavior to the alloys of copper, the oxidation characteristics of which have been studied in some detail5,6 The present research confirms this anticipation. The oxidation of a series of 20 dilute alloys of silver has been studied metallographically; some types of subscale not encountered among the copper alloys have been found. Instances of internal oxidation in alloys of most of the metals of the I-b and VIII groups of the periodic system are on record, but evidence of this type of oxidation in alloys of the metals of the intermediate groups is lacking. A number of the metals of the intermediate group, among them cadmium, lead, tin, and zinc, appear to provide the conditions essential to subscale formation; i.e., they form oxides with a relatively low negative free energy of formation, they dissolve other metals that form more stable oxides, and, presumably, oxygen will diffuse through them. In a study of 4o alloys of these white metals only a few cases of internal oxidation have been found. The probable reasons for this difference in behavior will be discussed presently. EXPERIMENTAL PROCEDURE Silver.-The silver alloys employed in the oxidation studies were prepared in heats of 30 grams each from high-purity silver (99.993 per cent Ag)* and the purest avail-

Jan 1, 1942

By C. R. Ince

THE term "differential flotation" is used to denote a flotation operation in which separation is effected between two or more minerals of the same class; e. g., lead sulfide from zinc sulfide, pyrite from blende, chalcopyrite from pyrite, chalcopyrite from blende. At present, so far as published work shows, there seem to be two theories as to the mechanics of differential flotation. The earlier and more generally accepted theory is that the so-called depressing agents alter the surface of one or more of the sulfides in the ore, either by chemical action or adsorption, so that it is no longer amenable to flotation, but that these depressed sulfides can be revived, after the unaffected sulfide has been floated, by reagents which react chemically with the altered surface and make it amenable to flotation. More recently, Professor Taggart1 has advanced the theory that slime adsorption is an important factor in differential flotation. He believes that, with the proper use of a class of agents, which he calls .dispersion agents and which include practically all the depressing agents, one can cause the slime to adsorb differentially on sulfide surfaces. A gangue-slime coated sulfide surface will act as a gangue particle and will not float. If, subsequently, an agent that will remove the gangue-slime coating is added, the sulfide again assumes its original surface and can be floated as an ordinary sulfide. This-is the basis of the slime theory of differential flotation. Timber Butte mill at Butte, Mont., is a typical lead-zinc flotation concentrator. Neihart ore, chosen for investigation in this work, is one of the custom ores treated at that mill. Practice at Timber Butte mill in February, 1928, was as follows: A combined lead-zinc concentrate was first made using 0.2 lb. per ton on the ore of potassium xanthate and 0.03 lb. per ton of Cleveland Cliffs oil after 1.5 lb. per ton of lime and 1 lb. per ton of calcium chloride has been added just before the ball mill. The concentrate was then thickened to 70 per cent. solids. Potassium cyanide to the amount of 0.3 lb. per ton and zinc sulfate in the quantity of 0.5 lb. per ton were added to the thickened pulp and the whole

Jan 1, 1929

By Axel Hultgren, B. Herrlander

THE original aim of the present investigation was to study the mechanism of cracking on hot-deforming red-short steels. During the microscopical examination of hot-deformed soft steels attention was directed to various patterns of so-called veining in the ferrite, as related to variations in the deformation procedure and the heat-treatment of the steels. Later, a hot-short steel of higher carbon content was also studied. Historical Storey1 suggested in 1914 that veining developed during the gamma-alpha transformation from the growing together of several alpha nuclei within the same gamma grain. Rawdon and Berglund2 found that in soft steel, forged somewhat below A3, the ferrite showed profuse veining, while usually there was very little veining after forging at very high temperatures. They emphasized the similarity between the pattern of veining formed by deformation about 600°C and that of slip lines formed by deformation at room temperature. They also suggested a relation between the gamma-alpha transformation and veining. They became convinced from etching and from the slip-line pattern in cold-deformed material, that the orientation within any ferrite grain showing veining was uniform. In recrystallized alpha grains veining was absent. Veining did not appear materially to affect the properties of ferrite. Independent of veining, continuous networks, attributed to preexisting delta and gamma grain boundaries were sometimes found, the former only in cast steel. Those networks were usually connected with small inclusions. Ammermann and Kornfeld3 confirmed that recrystallized ferrite grains showed no veining. In soft steel annealed between At and A3 there was veining only in the ferrite grains formed during cooling. Electrolytic iron deformed at 880° was free from veining. Bannister and Jones4 considered veining in ferrite to be a manifestation of microscopical and submicroscopical inclusions. Northcott,5,6 in studies on veining in steel and other metals and alloys, attributed veining to oxide inclusions. It could generally be removed by annealing in hydrogen, a suggestion earlier made by Rawdon and Berglund. Tritton (discussion in ref. 5) emphasized the importance of perfect polishing for bringing out veining by etching, and thought the veins or subboundaries were produced during the gamma-alpha transformation, when it was rapid, as a result of the volume change and contraction during cooling.

Jan 1, 1946

By P. A. Fisher, J. B. Wilson, D. J. Whitehead, C. J. P. Ball, A. C. Jessup

The properties of a new magnesium alloy ZT1 containing 3.0 pct Th, 2.5 pct Zn, 0.7 pct Zr are described. The alloy possesses good creep and fatigue resistance up to 650°F, is free from microporosity, and is readily sand-cast. ZT1 is shown to be superior to zinc-free Mg-Th-Zr alloys. THE advent of the jet engine created a demand for a light sand-casting alloy capable of being cast into large complex shapes and capable of resisting creep at temperatures up to 500°F. This demand has been largely met by alloys of the magnesium-cerium mischmetal-zirconium types, containing about 3 pct Ce mischmetal and 0.7 pct Zr, typified by Elektron magnesium alloys MCZ and ZREI, the latter alloy also having a zinc addition of 2.5 pct. These alloys utilize the valuable properties at elevated temperatures conferred by the addition of rare earth metals to magnesium, a fact which has been known for many years and discussed by several investigators.1-1 Murphy and Payne8 showed that the addition of the powerful grain-refining element zirconium to Mg-Ce mischmetal alloys produced alloys with attractive room temperature properties combined with good creep properties and castability. With the increasing power of modern jet engines the temperatures to which some of the magnesium parts are subject are likely to exceed the safe working range of the cerium-mischmetal-containing alloys, and at the beginning of the research considerable interest had been shown by aeroplane engine designers in a magnesium sand-casting alloy suitable for service at higher temperatures, e.g., 600°F and above. At an early stage in the development of this type of alloy a check on the fatigue properties at elevated temperatures indicated that, since the fatigue limit even at 108 eversals was appreciably higher than any permissible creep stress, the main emphasis of the research could be concentrated on creep behavior. The primary aim in developing the new alloy has therefore been to attain maximum creep resistance; but due consideration has also been given to other important properties such as castability, tensile strength, and cost. It is by now well established that it is not possible to correlate creep strength with other short time mechanical properties such as are obtained in tensile

Jan 1, 1954

By J. Kent Smith

The object of this investigation was to ascertain the effect of varying percentages of beryllium upon pure copper and the properties of the resultant alloys in their softest condition, the effect of heat hardening on them, and the extents to which these properties could be augmented by different combinations of heat hardening and cold rolling. The data compiled in this paper represent partial results of continuing work done by the writer during the years 1930 and 1931, which was a continuation of the unpublished ground work incepted in the laboratory of the Beryllium Corporation of America by H. B. Pulsifer in the year 1926. A short bibliography on beryllium alloys is appended to this paper. It has, of course, long been known that copper subjected to cold work is hardened and strengthened to a considerable extent; furthermore it had been qualitatively noted in previous experiments that copper-beryllium alloys seemed to take on hardness and strength as the result of cold work at a greater rate even than does plain copper. It was decided therefore to endeavor quantitatively to determine such rate of increase, as also the relative increases by combinations of cold working and heat hardening. The results are summarized in Tables 3, 4 and 5. A preliminary series of experiments had indicated that by an exposure to the heat of 575" F. for 2 1/2 hr. age-hardening of a 2.50 per cent beryllium-copper alloy took place. Slab ingots of nine different beryllium-copper alloys were prepared under identical conditions by means of the addition of a previously prepared 12.5 per cent beryllium-copper alloy to well melted and deoxidized pure copper. The ingots were then reduced by hot rolling to 12 gage (about 0.080 in.). These strips were heated to 1450" F. and quenched in cold water, and thus brought to their softest condition. (See Table 1.) Strips were next "precipitation-hardened" by reheating to a definite temperature. Similar strips to those itemized in Table 1 (which had been quenched from 1450" F.) were reheated for varying periods of time at 575" F. The hardness figures show that a metastable condition, of which the range of stability is dependent entirely upon time at the given temperature, begins to be noted in copper samples containing as little as 0.85 per cent beryllium. It is extremely noticeable in samples containing

Jan 1, 1932

By C. R. Ince

The term "differential flotation" is used to denote a flotation operation in which separation is effected between two or more minerals of the same class; e. g., lead sulfide from zinc sulfide, pyrite from blende, chalco-pyrite from pyrite, chalcopyrite from blende. At present, so far as published work shows, there seem to be two theories as to the mechanics of differential flotation. The earlier and more generally accepted theory is that the so-called depressing agents alter the surface of one or more of the sulfides in the ore, either by chemical action or adsorption, so that it is no longer amenable to flotation, but that these depressed sulfides can be revived, after the unaffected sulfide has been floated, by reagents which react chemically with the altered surface and make it amenable to flotation. More recently, Professor Taggartl has advanced the theory that slime adsorption is an important factor in differential flotation. He believes that, with the proper use of a class of agents, which he calls dispersion agents and which include practically all the depressing agents, one can cause the slime to adsorb differentially on sulfide surfaces. A gangue-slime coated sulfide surface will act as a gangue particle and will not float. If, subsequently, an agent that will remove the gangue-slime coating is added, the sulfide again assumes its original surface and can be floated as an ordinary sulfide. This is the basis of the slime theory of differential flotation. Timber Butte mill at Butte, Mont., is a typical lead-zinc flotation concentrator. Neihart ore, chosen for investigation in this work, is one of the custom ores treated at that mill. Practice at Timber Butte mill in February, 1928, was as follows: A combined lead-zinc concentrate was first made using 0.2 Ib. per ton on the ore of potassium xanthate and 0.03 lb. per ton of Cleveland Cliffs oil after 1.5 lb. per ton of lime and 1 lb. per ton of calcium chloride has been added just before the ball mill. The concentrate was then thickened to 70 per cent. solids. Potassium cyanide to the amount of 0.3 lb. per ton and zinc sulfate in the quantity of 0.5 Ib. per ton were added to the thickened pulp and the whole

Jan 1, 1930

US 4,135,913-Extraction of nickel values from iron-containing nickel sulfide ore, particularly pentlandite or nickeliferous pyrrhotite A mixture of raw ore, roasted ore, or iron powder, and coal as a reductant is heated to a temperature of 800- 1000° C in a nonoxidizing atmosphere to convert the bulk of the iron content to metallic iron while diffusing into the iron the bulk of the nickel, the mixture cooled, and the cool material separated into a magnetic fraction containing most of the nickel and a non-magnetic gangue fraction A Illis arid L S Renzoni, assigned to International Nickel Co, Inc Jan 23, 1979 7 pp (75-21) Filed 10-10-75 (621,343) Priority Canada, 10-27-72 (155,032) Same Canadian 981,910, dated Jan 20, 1976 Same British 1,389,145, dated Apr 3, 1975 US 4,135,917-In the recovery of gallium from a solution obtained by the digestion of bauxite or nepheline in an alkali solution for the production of alumina, the digestion solution is neutralized, the neutralized solution evaporated to an op¬timum caustic alkali concentration and adjusted to a ratio of alkali metal oxide to alumina of above 2, the corrected solu¬tion contacted with a gallium-aluminum alloy, arid high-purity gallium recovered from the solution by electrolysis or cemen¬tation K A Badaliants, et al Jan 23, 1979 6 pp (75-109) Filed 12-19-77 (862,201) Priority USSR, 12-22-76 (2,428,¬006) US 4,135,918-Extraction of copper from copper sulfide ore containing also one or more of the metals iron, nickel, arid cobalt Ore is roasted at a temperature of 750-800° C to expel sulfur, the sulfur-free calcine slurried in water containing a sufficient amount of sulfuric acid to supplement any sulfuric acid formed in situ, the slurry heated at 150-165° C in the presence of a reducing gas to form soluble sulfates of metals other than copper while reducing copper to elemental form, arid the slurry filtered to recover copper solids Any precious metals present in the ore will report with the copper solids V A Ettel, A P Devuyst, R Sridhar, arid C. E O'Neill, as¬signed to International Nickel Co, Inc Jan 23, 1979 5 pp (75-117) Filed 3-2-78 (882,610) Priority Canada, 5-13-77 (278,360)

Jan 1, 1980

TWO recent developments in open hearth steelmaking have had a substantial impact on metallurgical practices and operating procedures. These are: (1) the use of oxygen roof lances for accelerating the refining reactions, and (2) the use of a spring-arch, basic roof for prolonging the life of the furnace. Although these practices can be used separately, they are generally used to complement each other in an effort to obtain minimum heat time consistent with an acceptable rate of wear of the refractory roof, walls and port ends. DECARBONIZATION BY OXYGEN INJECTION The use of oxygen to speed carbon elimination was perceived by Sir Henry Bessmer but its practical use in steelmaking could not be realized until processes were developed for the manufacture of low cost, tonnage oxygen. However, as early as 1922 Bigge1 obtained a patent covering the use of gaseous oxygen to speed decarbonization of a molten steel bath. At that time, oxygen was available only in bottles and at a cost of $240 per net ton. At the end of World War II the price of oxygen had dropped to $80 per net ton, and as a result, metallurgical oxygen (99.5 per cent began to come into widespread experimental use for decarbonization in open hearth and electric furnace shops.2-8 Even this price prevented oxygen's routine use for other than decarbonizing the bath in shops producing substantial quantities of steels containing less than 0.40 per cent carbon. Today, tonnage metallurgical oxygen can be manufactured for less than $15 per net ton, and commercial purity oxygen (95 per cent is reported to cost less than $5 per ton. Thus, it is not at all surprising to find many open hearth shops effectively using large quantities of oxygen to accelerate decarbonization. Equipment for Oxygen Injection. The oxygen may be injected by a lance pipe inserted through the wicket hole and pushed several inches into the steel bath, or by a water-cooled jet inserted through the back- wall, endwall, or roof, and immersed in the slag or set just a few inches above the slag. Oxygen at approximately 100 psi is piped directly to control stations adjacent to each furnace. The installations should include adequate safety devices such as fire checks and emergency valves,

Jan 1, 1964

By R. M. Bird

Few persons outside of the foundry trade have any conception of the great variety of sands now regularly specified and furnished, nor of the differences in foundry practice frequently resulting from apparently minor changes in sands. Conditions in each locality where the sands are mined and prepared necessitate special equipment designed to perform the work efficiently. The description that follows of the foundry-sand producing operations is typical of the areas in New York and New Jersey, and particularly refers to the operations of the George F. Pettinos Co. A few years ago the so-called Albany sands were dug by simple methods and hauled by horsecart to railroad. Depletion of sand near railroad sidings and extended use of automotive power have appreciably extended the area from which sand is now being dug. It is not unusual to haul 5 miles to the railroad. As stripping is quite shallow, 6 to 18 in., and the banks of usable sand generally run from 12 in. to 4 ft., it is economical to work the bank by benches so narrow that the overburden can be thrown by hand shovel to the exposed bottoms. In effect the top soil goes back to where it was, but on a lower level. Consequently the general surface appearance of a mined acreage is the same as before. This condition is in fact cutomarily required when a farm owner sells his sand in the ground. After such replacement, in the course of 3 to 5 years the soil is no less fertile than it was before mining. The sand itself varies as to grain and bond vertically and also along the breast. No mechanical equipment has been developed to compete with hand shovels and no machine has as yet been devised that grades the sand as required. Uniformity of sand, as shipped, depends first, last and all the time on the man on the job. Mixing equipment can change the appearance of the sand and mask its lack of uniformity, but it will never correct wrongly graded sand, dug from the bank. Modern methods of testing are helpful in setting up standards against which the man in the bank can compare his sands, but a good bank foreman is the only assurance that the sand, as dug, matches the required sample.

Jan 1, 1926

By V. C. Allison

The explosibility of a dust is favored by its fineness and content of volatile combustible matter; its explosibility is decreased by its moisture and ash content. The explosibility of a dust can be reduced by admixture of either inert dust or water. The major effect of both the inert dust and water lies in their heat capacity; they absorb the heat of the explosion flame until the temperature of this flame drops below the ignition temperature of the explosive heat. The amount of inert dust necessary to make an explosive dust non-explosive can be calculated from its proximate analysis. FOREWORD LARGE-SCALE testing of the explosibility of coal dust as conducted by the Bureau of Mines in its Experimental Mine involves a large initial investment, and a high charge for maintenance and conduct of the test; in addition the work is necessarily slow because of the time required for the preparation of the tests and the cleaning and repairing of the mine after each test. These tests have been made along practical mining lines that admit of a range of mixtures of dust varying from 5 to 10 per cent. and with gas as low as 0.5 per cent. increments. Because of the time and expense involved, efforts have been made to devise a type of gallery for laboratory use in which the results obtained in the Experimental Mine may be correlated as an aid in a study of dusts, the explosibility of which might be approximately determined quickly and at a minimum of expense. The explosibility of coal dust has been studied by a number of European investors, using small laboratory devices; among these may be mentioned the experiments con¬ducted by Galloway, Vital, Hall and Clark, Abel, Mallard and Chatelier, Thorpe, Bedson and Widdas, Engler, Holwartz and Meyer, and Taffanel, results of whose experiments have been reviewed by the Bureau of Mines., The Bureau has conducted many tests with the Frazer-Clement2 apparatus, which gives the pressures set up when the dust cloud within is, ignited with a platinum coil or tube, heated to different temperatures, but for these tests the sample must be especially prepared as to size (200 mesh) and must be dry. An attempt has been made to design an apparatus that may be used for checking and correlating the experimental tests. The first design was a wooden gallery, 8 by

Jan 7, 1925

By David Turnbull

STAFF: Editor, Gerhard Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: J. S. Smart, Jr., President; C. C. Long, Past-President; K. L. Fetters, Vice President; T. D. Jones, Treasurer; R. W, Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: C. L. McCabe, Chairman; H. L. Bishop, K. L. Fetters, J. J. Harwood, W. A. Krivsky, F. C. Langenberg, R. E. Lund, W. O. Philbrook, L. L. Seigle, R. L. Smith, and F. L. Vogel. Review and selection of monuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: C. L. McCabe, Chairman; R. E. Lund, Vice-Chairman; D. H. Baker, Jr., W. A. Krivsky, R. A. Lewis, Paul Queneau, A. S. Russell, R. E. Shinkoskey, W, W. Stephens, and M. E. Wadsworth. Institute of Metals Division: L. L. Seigle, Chairman, Paul A. Beck, I. I. Bessen, J. 0. Better-ton, Jr., J. B. Clark, R. S. Davis, A. E. Dwight, R. W. Fountain, R. B. Gordon, C. D. Graham, Jr., R. W. Guard, J. C. Gurland, E. L. Harmon, J. J. Heger, A. A. Hendricksan, M. Herman, J. N. Hobstetter, H. H. Johnson, Jr., R. R. Nash, T- N. Rhodin, R. H. Richman, W. Ros-toker, P. G. Shewmon, C. W. Spencer, L.SIifkin, J. K. Stanley, C. D. Starr, and H. C. Stumpf. Iron and Steel Division: H. L. Bishop, Chairman; R. E. Boni, F. C. Langenberg, J. B. Wagstaff, and T. V. Wainwright. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1961 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York .. . Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts . . . Second class postage paid at New York, N. Y., and Ann Arbor, Mich. Volume 221, Number 3.

Jan 1, 1962

By W. T. Lundy

THE forms in which sulphur is commonly found-native sulphur, sulphides of many metals and sulphates-are widely distributed throughout the world. The two first mentioned are the principal sources of sulphur. Substantial amounts of sulphur in some form are recovered from gases from industrial plants and from gases from smelters treating other minerals. In recent years, plants have been installed in the United States to recover sulphur in elemental form from sour gases."' The amount of sulphur so produced is small at the present time but undoubtedly will increase in the future. The recovery of sulphur from gases is not covered in this chapter, which is confined to: (1) native sulphur deposits of Texas and Louisiana; (2) those of Italy; (3) other scattered deposits of native sulphur; and (4) pyrites deposits found in many countries of the world.30 Sulphur, a nonmetallic element, occurs normally in well developed bipyramidal or tabular crystals of the orthorhombic system, as well as in stalactitic and earthy masses. The mineral has a distinctive yellow color, which may be dark and discolored by impurities; the streak is white; the luster is resinous; and the fracture is conchoidal to uneven. Sulphur is translucent to opaque; has a hardness of 1.5 to 2.5, a specific gravity of 2.05, and an atomic weight of 32.06.16 The molecular weight of the solid is expressed by the symbol SS and that of the liquid and vapor ranges from S2 to S8, depending on the temperature. Sulphur melts at a temperature between 2340 and 248°F, depending on its crystalline state, to a liquid of dark amber color, the boiling point of which is 832°F. The viscosity near the melting point is about that of water and increases to 50,000 times that of water at a temperature of 380°F, subsequently falling rapidly to a low figure at the boiling point. Crystallization changes slowly from rhombic to monoclinic above 205 °F and in cooling the transformation is reversed. The mineral is a very poor conductor of heat and electricity; it is insoluble in water and nearly all acids and is soluble in cold carbon bisulphide and carbon tetrachloride. It ignites in air at a temperature of 478°F, burning with a distinctive blue flame with evolution of sulphur dioxide.47

Jan 1, 1949