Search Documents

In a straight caving system, the ore is first undercut and then broken down by its own weight or .by the weight of the overlying rock, or by a combination of both. Operations that involve the caving of the material overlying an orebody as an essential part of the work are also classed as caving, though practically all the ore is broken by drilling and blasting. Actually there are two distinct methods—sublevel caving and block caving, and modifications thereof. The mines described are Miami and Alaska Juneau.

Jan 1, 1925

By James Gayley

The development of blast-furnace practice in America in the direction of large yields is mainly the history of our working since the year 1880, as the advancement that has been made in the last decade is greater than that in the third of a century previous. A new era in the manufactnre of pig-iron began in 1880 with the putting in blast of the Edgar Thomson furnaces. These furnaces at once leaped to the front as pig-iron producers, and have maintained that position—with but one brief interruption—ever since. I shall, therefore, confine myself mainly to a description of these works, showing the changes in design and practice by which these results have been achieved. In order to show more clearly the progress that has been made since 1880, I shall refer briefly to the best work that was done in the ten years previous to that time. The Struthers furnace, in Ohio, was one of the first to attract attention in the matter of large outputs. This furnace was 55 feet high, 16 feet in diameter of bosh, 9 feet in the hearth, and about 8 feet 6 inches at the stock-line. The fuel was raw coal. This furnace, in December, 1871, made 1602

Jan 1, 1891

By P. F. Gnirk

Consideration is given to creater formation with shallow, contained, chemical explosions in rock masses which exhibit different inherent physical and mechanical properties as determined by standard laboratory techniques. The primary purpose is to determine whether or not a simple but useful generalized correlation can be established between explosive crater formation and one or more common rock properties. Such a correlation could be beneficial in predicting with some degree of reliability the size of a crater which could be expected in a particular rock type for a given input of explosive energy. A series of crater formation experiments employing constant weight charges of Gelex 2 explosive was conducted in five submembers of the taconite formation at the eastern end of the Mesabi Range in northeastern Minnesota. Five mechanical and physical properties-unconfined tensile and compressive strengths, Young's modulus of elasticity, longitudinal wave velocity, and density-were determined by conventional laboratory techniques using core samples from the taconite submembers. Although insufficient data were obtained to warrant the use of mathematical methods in the determination of empirical relationships, the results provided a fairly strong indication that with an increase in magnitude of any one of the five rock properties definite decreases in the optimum crater volume and surface area occur. Furthermore, for a constant explosive energy input, the presence of bedding planes and joint systems in a rock mass influences the formation of craters in such a manner as to increase the volume of rock broken substantially above that expected from the same rock mass without joint systems and, in particular, without bedding planes.

Jan 1, 1968

By L. W. Saperstein, W. B. Wells, L. B. Phelps

Several strip mine spoils are being examined to better understand their physical nature. The spoils were core drilled and each hole was logged using a nuclear geophysical tool to obtain bulk density data. Bulk density is an important property which provides insights into spoil porosity as well as other characteristics. The holes were drilled in spoils representing a variety of overburden removal methods, spoil ages, spoil depths, and area lithology. The relationship between bulk spoil density and mining method, spoil age, spoil depth, particle size, and lithotype is presented.

Jan 1, 1984

US 4,194,902 - Pig iron or other molten lion is effectlvely desulfurized by treatment with a mixture preferably about 60% by weight commercial grade calcium carbide, 30% dried limestone diamide, and the remainder bituminous coal. Equivalent desulfurization is obtained using a significantly lesser amount of desulfurizer than in previous mixture of calcium carbide and limestone diamide W Gmohling, assigned to SKW Trostberg AG. Mar 25, 1980. 3 pp. (75-55) Filed: 9-12-78 (941,659) Priority. West Germany, 9-15-77 (2,741,588). Same. British 2,008,153, dated May 31, 1979.

Jan 1, 1982

By Guy R. Johnson

It is now generally acknowledged that the successful management of a modern foundry necessarily embraces a knowledge of chemistry, and especially a thorough acquaintance with the effect of the various metalloids on cast-iron, in order to

Jan 1, 1897

By Robert C. Bates

Published information on costs of radon daughter control in uranium mines was analyzed to develop estimates of the cost per ton for any level of radiation exposure control. All data were converted to 1967 cost of living index to provide a common analysis base. Re- of the analysis show that the cost per ton increases exponentially as the radiation level is lowered. A linear relationship with the cost of living index is assumed, and equations and graphs are provided to estimate control cost per ton for any exposure control level and cost of living index.

Jan 1, 1982

By Morris J. Elsing

FOR MANY YEARS lead and zinc have had the so-called protection of a tariff and it is the purpose of the following brief discussion to show what' such protection actually accomplishes with a view to forecasting the possible results of the present copper tariff. In analyzing the subject, tabulations of the United States production, consumption, imports and exports, including ore and concentrates and all of the metallic products, of both lead and zinc have been made for each year since 1900. Of these data, the relationship of the imports and exports and the relative foreign and domestic prices are shown in Table 1. The conclusions drawn from these figures are listed below. 1. The United States is an exporter of zinc. 2. The United States is an importer of lead. 3. The average price of zinc at St. Louis for the last 32 years has been no higher than on the London market even though zinc and zinc ore have "enjoyed" a protective (?) tariff of varying amounts per pound for 22 years of this period. 4. The average price of lead on the New York market for 32 years has been 1.2c. per pound higher than on the London market, the tariff varying from 0.75 to 1.5c. per pound of lead in ore, and 1 to 2c. or more on manufactured lead.

Jan 1, 1932

By E. T. Dumble

PROF. EDWARD ORTON, in his Report on the Occurrence of Petroleum, Natural Gas and Asphalt Rock in Western Kentucky, thus clearly states his ideas of the universal dissemination and rare accumulations of the bitumens:1 " We need to bear in mind that the various members of the bituminous series are abundantly and almost universally distributed among the unaltered sedimentary rocks of the earth's crust. The valuable accumulations of these substances are rare, it is true, but one can scarcely go amiss of petroleum, asphalt or gas, at least in small quantities, among the stratified rocks that retain their original structure." Speaking of the Ohio valley, he adds: "A fifth of one per cent. of petroleum, if distributed through a, thousand feet of rock, would make a total to the acre, or square mile far , beyond any production that has ever been realized from the richest oil field, and percentages of this amount are not only not rare to find, but are even hard to miss." Dr. F. W. Clarke in his Data of Geochemistry (Bulletin No. 491, U. S. Geological Survey, 1911), discussing these views of Orton with similar views of T. Sterry Hunt and Szajnocha, says that they "lead to the conviction that the formation of bitumens is a general process and by no means exceptional. Wherever sediments are laid down, inclosing either animal or vegetable matter, there bitumens may be produced."2 The organic origin of the bitumens, including petroleum, has long been an accepted fact with nearly all geologists, but the method, place, and time of the transformation into petroleum or other bitumen is still under discussion.

Jan 3, 1914

By G. Thodos, R. J. Smialek

A method has been developed that permits the correlations of Mehra and Thodos8 and Dastur and thodos2 for binary systems to be used for the prediction of the vapor-liquid equilibrium constants of the light and heavy constituents, Kland Kh, of a ternary hydrocarbon mixture. Furthermore, the unique relationship observed in this study, i.e., a plot of log Ke/Ki vs log Kp/K h is linear and passes through the origin, permits the calculation of the K-value for the intermediate component. This approach has been used to establish K-values for the constituents of the three ternary hydrocarbon systems used to develop this method and has also been applied to two additional ternary hydrocarbon systems to yield an average deviation of 7.7 per cent resulting from a total of 294 points for the five ternary systems considered. INTRODUCTION The rigorous calculation of vapor-liquid equilibrium constants for systems containing two or more components is a difficult problem and becomes extremely complex at elevated pressures and for conditions approaching the critical point. Although thermodynamic relationships can be developed to account for the vapor-liquid equilibrium behavior of simple systems, their use is limited because the necessary PVT data for these systems are not generally available. To establish a method for calculating K constants directly, without any recourse to the PVT behavior of a system, Mehra and Thodos8 applied the principle of corresponding states to the vapor-liquid equilibrium constants of binary hydrocarbon systems. They developed a series of charts which made possible the prediction of K-values for all binary hydrocarbon systems not containing methane. This work has been extended by Dastur and Thodos2 to include binary hydrocarbon systems containing methane. The charts developed in these two studies cover the high-pressure region and are applicable to conditions in the vicinity of the critical point. The ability of this approach to predict vapor-liquid equilibrium constants of binary hydrocarbon systems suggests that this method may be extended to the prediction of the K-values of the components of ternary hydrocarbon systems. In this investigation, the charts developed for both the methane and non - methane binary systems,2,8 together with mixture rules developed in this study, have been used to predict the K-values of the light and heavy components of a ternary hydrocarbon system. These calculated values are then used to establish the K-value of the intermediate component through the use of a novel relationship developed in the present study. DEVELOPMENT OF METHOD FOR PREDICTING K-VALUES OF TERNARY SYSTEMS The application of the corresponding state charts developed for binary hydrocarbon systems is restricted to those systems containing two components. The extension of these correlations to three-component systems requires that the ternary system be reduced to an equivalent binary, which can be treated in a manner consistent with the corresponding state development. To establish such an approach, the vapor-liquid equilibrium constant of the light component K is first calculated by assuming that the ternary mixture consists of the light component and a pseudo-heavy component of the intermediate and heavy constituents of the original ternary. To establish the vapor-liquid equilibrium constant of the heavy component Kh, the light and intermediate constituents of the ternary are combined to form a pseudo-light component of another equivalent binary system. The calculated values Kl and Kb are then utilized to calculate the vapor-liquid equilibrium constant of the intermediate component EQUILIBRIUM CONSTANT FOR LIGHT COMPONENT K To calculate the K value of the light (most

Jan 1, 1965

By Oswald J. Heinrich

IN this paper I shall attempt a description of the successful extraction of coal from this property after it had been on fire for probably fifty years, or more, and after attempts, made at various times, which had still left considerable coal behind. The Richmond coal-field has a well-founded bad reputation, arising from the circumstance that many of its collieries have had to be abandoned, from time to time, if not entirely, on account of fires, caused by spontaneous combustion, to which the character of the coal in this field renders them peculiarly liable. While I fully assent to the opinion that this trouble lies in the nature of the coal, which is highly bituminous, and the seams of which are, moreover, divided by slaty bands, through which, as also in the coal, iron pyrites is more or less disseminated, often in microscopically small particles, I must, nevertheless, declare that many lamentable disasters, causing great loss of life and property, could have been avoided if a suitable system of mining had been pursued in all the collieries. If this could not have been done from the beginning of mining in this section of country (the history of which can be traced back to over one hundred years), at least experience enough existed upon this subject thirty and forty years ago to dictate the avoidance of the dangers to a considerable extent. It is therefore necessary here to refer first, in a few remarks, to the character of the coal deposits, particularly in this immediate neighborhood, the Midlothian being one of the oldest and most extensive mines, and some of its coal being much subjected to spontaneous combustion. I must also refer to the history of former managements to explain more clearly the results which were arrived at. The Midlothian coal-mine property, situated upon the eastern outcrop of the basin, about four miles south from James River, exhibits

Jan 1, 1873

By Oswald J. Heinrich

IN this paper I shall attempt a description of the successful extraction of coal from this property after it had been on fire for probably fifty years, or more, and after attempts, made at various times, which had still left considerable coal behind. The Richmond coal-field has a well-founded bad reputation, arising from the circumstance that many of its collieries have had to be abandoned, from time to time, if not entirely, on account of fires, caused by spontaneous combustion, to which the character of the coal in this field renders them peculiarly liable. While I fully assent to the opinion that this trouble lies in the nature of the coal, which is highly bituminous, and the seams of which are, moreover, divided by slaty bands, through which, as also in the coal, iron pyrites is more or less disseminated, often in microscopically small particles, I must, nevertheless, declare that many lamentable disasters, causing great loss of life and property, could have been avoided if a suitable system of mining had been pursued in all the collieries. If this could not have been done from the be-. ginning of mining in this section of country (the history of which can be traced back to over one hundred years), at least experience enough existed upon this subject thirty and forty years ago to dictate the avoidance of the dangers to a considerable extent. I t is therefore necessary here to refer first, in a few remarks, to the character of the coal deposits, particularly in this immediate neighborhood, the Midlothian being one of the oldest and most extensive mines, and some of its coal being much subjected to spontaneous combustion. I must also refer to the history of former managements to explain more clearly the results which were arrived at. The Midlothian coal-mine property, situated upon the eastern outcrop of the basin, about four miles south from James River, exhibits

By David R. Mitchell, R. B. Hewes

MANY processes for cleaning coal that are in use depend primarily on physical properties of coal and refuse other than specific gravity and surface conditions relating to froth flotation. These properties are shape, coefficient of sliding friction, resilience, friability, magnetic susceptibility, and electrical conductivity. In many of these processes specific gravity does have some effect and many separators are designed to utilize more than one of the physical properties cited. Although the processes described herein do not have a widespread application, yet for specific coals and specific conditions, they are economically important. A problem confronting many coal-mining districts is the marketing of the slacks or screenings and dust passing the final sizing screens. Processes in commercial use installed primarily to increase the form value, and hence the market value, of these slacks and dusts include briquetting, packaging, and low-temperature carbonization. MECHANICAL PICKERS Machines utilizing shape, frictional resistance, and differences in resilience of coal and impurities are usually called mechanical pickers. They require a closely sized feed, therefore their use is confined to the pea, nut, and egg sizes. Various types of these devices are described by Berrisford, 1, 2 Taggart,3 and Peele.4 Shape In general, coal differs in shape from its accompanying dirt throughout the range of commercial sizes. Coal, breaking into roughly cubical particles, contains a greater number of axes that are approximately the same length than does the dirt. The latter, consisting of pieces of slate and shale and lenses of pyrite, is flatter in nature. Further, flat coal often has a dirty, slaty appearance, even though of high quality. Mechanical pickers known as flat pickers, or "flatters," are widely used in the Pennsylvania anthracite region to remove flat coal .from the final clean coal. This practice greatly improves the appearance of the final market product. Flat pickers for removing impurities or flat coal ("flats") are usually installed on shaker screens, shaking conveyors, and chutes. In Fig. 1 three

Jan 1, 1950

By Adrien Berton

FOR nearly a century, the Corocoro deposit has been renowned among geologists from the fact that it shares with the Lake Superior deposits of the United States the distinction of being the only important copper districts where native copper is worked commercially. The Corocoro district, named after the city of Corocoro, the capital of the Province of Pacajes (Department of La Paz, Bolivia) is situated towards the western edge of the Bolivian high plateau, at an altitude of a little over 13,000 ft. The most interesting part of the district is that immediately surrounding the city of Corocoro, at a distance, by railway, of 65 miles from La Paz and 210 miles to the Chilean port of Arica on the Pacific Coast. The climate of the region is that of the semi-desert, dry and relatively cold, with big differences of temperature between day and night. The rainy season begins in December and ends in March. The cupriferous lodes of Corocoro have not attracted as much interest as the silver mines of Potosi but they have been known for a long time. In the precolonial period the Indians were using the charquis, or natural native copper sheets, to make small brass objects, and the beautiful pale green brochantite of the outcrops as a source of green pigments. During the colonial period, the oxidized ores of the outcrops were worked for copper, which was used by the mint at Potosi for making currency. The native copper ores were neglected because the Spanish miners were at a loss how to concentrate and smelt them. About 1830, work by rudimentary processes, which were improved little by little, was begun on the native copper ores. The total production of native copper in the following hundred years amounted to 100,000 tons. This native copper, which was remarkably pure, was much appreciated on the European markets before the introduction of electrolytic copper. It was useful for making special ornamental brass or bronze and the granular concentrates of native copper, called barrilla, containing 80 to 85 per cent copper were suitable for making copper sulfate by direct oxidation and subsequent leaching with sulfuric acid.

Jan 1, 1936

By J. M. Larkin

GOOD will is becoming recognized more and more as a necessary business asset, and a successful concern must have the good will not only of its customers and the public, but of its employees. Management -enlightened management-recognizes this and will go the limit to get it. Progress depends on cooperation, and in industry cooperation must be based on the acceptance by employ-ers and employees of some practical application of the principle that capital and labor are interdependent. Capital cannot exist without labor, and labor without capital is helpless. The development of each is depen-dent on the cooperation of the other. Confidence and good will are the foundation of every successful enter-prise, and these can be created only by securing a point of contact between employer and employee. We feel that one of the most effective agencies for promoting good will between employers and employees is through some well organized method of conference and have consequently adopted, to accomplish this, a plan of employee representation. The plan inaugurated by the Bethlehem Steel Co. about four years ago, which provides for the election by secret ballot of representatives by and from among the employees, has for its purpose three fundamentals; namely, to give the employees a voice in the determina-tion of the conditions under which they work, to furnish machinery for the prevention and adjustment of differ-ences between employees and management, and, so far as possible, to provide and foster continuous employment. The constitution and by-laws adopted take care of the detail in setting up machinery for the functioning of the representatives of both management and men, but the spirit with which the plan has been carried out and the results which have been accomplished are of far greater importance than the plan itself. The Bethlehem plan, which has been in operation since October, 1918, can no longer be classed as an experiment. The original by-laws provided for amend-ments and, as was anticipated, changes and improve-ments have been made from time to time by mutual agreement. The operation of the plan for over four years shows it to be fundamentally sound and that it must therefore be conceded a success.

Jan 2, 1923

By Robert B. Hall, Charles W. Bauer

Alunite, KA13(SO4)2(OH)6, was used from the 15th century until early in the present century as a source of potash alum and aluminum sulfate. Since early in this century its use for this purpose has declined to virtually nil with acid treatment of bauxite or clay replacing alunite as a source of alum. During the First World War alunite served as an emergency source of potassium sulfate fertilizer in the United States and Australia. More recently, alunite has been investigated as a nonbauxite ore of aluminum, with potassium sulfate and sulfuric acid as recoverable byproducts. The Soviet Union established a commercial-scale plant in the mid-1960s producing cell-grade alumina from alunitic ore and recovering byproduct potassium sulfate and sulfuric acid. Interest in nonbauxite ores, including alunite, is expected to continue in countries that presently are dependent on imports of bauxite or alumina to support their aluminum industries. The US has the largest aluminum producing and fabricating industry in the world but imports more than 90% of its aluminum-bearing raw materials. This chapter reviews the status of alunite as a potential source of aluminum with byproduct fertilizer, and the resources available to support this industry, whenever this becomes economically feasible. Historical Background Alunite has received little attention until recently, yet for centuries it held a higher place than many of the industrial minerals considered essential today. The deposits of alunite at Tolfa, northwest of Rome, were mined almost continuously from 1462 until about the middle of the present century (DeLaunay, 1907; Lombardi, 1977). The potash alum made from the alunite, called Roman alum, was a valued commodity in international trade, being used in the making of paper, in tanning leather, and as a mordant in textile dyeing. The industry at Tolfa is said to have been controlled by the Vatican and was a source of revenue for the Papal State until fairly recent times (Lombardi et al., 1977). Since early in the present century, the preferred method for making alum has been by acid treatment of bauxite, clay, or other aluminous material, so that alunite has fallen into near-total disuse as a source of alum chemicals. Appreciable quantities of mixed alunite-kaolin rock still are quarried in the Tolfa district for use by the Italian cement industry (Lombardi and Mattias, 1979), but the role of this material in the making of Italian cement is not clear. A large deposit of alunite-bearing rock in Chekiang province, mainland China, is said to have yielded a "great quantity" of alum over a period of several centuries (Yih, 1931). During the 19th century, alunite deposits in France, Spain, Australia, and other countries were exploited as raw material for making potash alum and aluminum sulfate. Interest in alunite was revived during the First World War, not for alum, but as an emergency source of potassium sulfate fertilizer. Large veins of nearly pure alunite had just been discovered on Alunite Ridge, 11 km southwest of Marysvale in Piute County, Utah (Butler and Gale, 1912), and these were quickly brought into production for making potash fertilizer to replace supplies cut off from the famous deposits at Stassfurt, Germany. An estimated 225 kt of Marysvale alunite was mined and processed at that time (Callaghan, 1973). Similarly, Australian alunite deposits were mined as a source of potash fertilizer during both world wars (Hall, 1978).

Jan 1, 1983

By E. J. Quinn, M. F. Fogler

In a recent paper, Rawdon and Mutchlerl gave some exceptionally interesting results on the Brinell and scratch hardness of severely cold-worked metals. In their work, they found that, on continued cold rolling, the metal hardened up to a particular point and then reversed and became softer; this was true for both Brinell and scratch hardness values. The generally reported behavior2 of metals, with respect to Brinell tests on cold-worked material, is that the metals harden up to a certain point and then, on further cold rolling, no change in Brinell hardness occurs. Jeffries and Archer3 state that there is little difference between the scratch hardness of annealed and cold-worked metals; the work of Faust and Tammann4 also indicated no difference between the hardness of annealed and cold-worked copper. Rawdon and Mutchler found, when they plotted the reduction ratio (initial thickness divided by thickness after rolling) against the hardness value for the cold-rolled material, that the hardness number increased up to a reduction ratio of about 3 and then decreased and became even smaller than that for the annealed metal. This behavior was reported for both scratch and Brinell hardness; Figs. 1 and 2 show their results for Brinell hardness on the metals for which they published data. This is an exceptionally interesting phenomenon, if it occurs under all conditions of rolling, and would have an important bearing on the practice of cold

Jan 1, 1925

The resolution drafted by J. W. Richards, J. V. N. Dorr, and Allen H. Rogers on the death of J. E. Johnson, Jr., and adopted by the Board of Directors, is as follows: "The Boards of Directors of the American Institute of Mining and Metallurgical Engineers wishes to place on record its great personal loss in the sudden death of Mr. J. E. Johnson, Jr., our fellow Director of the activities of the Institute, a member our Executive Committee, Chairman of the Institute's Committee on Admissions, and Vice-chairman of its Iron and Steel Committee. "A mere recital of these positions of trust and responsibility, which he filled with conscientious efficiency and marked ability, shows how greatly the Institute has lost by his death. No one else of the Institute's officers could have been so illy spared. We, his colleagues, take up his tasks with a sense of our inability to discharge them as well as he, and this with a doubled sense of our loss. "Others have written and spoken of the blow which his death has been to the furtherance of the metallurgy of iron and steel. His pre-eminence in this line is one of the facts of which the Institute is justly proud. Here his personality, originality, courageousness in advocating new principles, clearness of writing and forcible presentation of facts, are irreplaceable. His two great treatises on the blast furnace are his literary and scientific memorial.

Jan 7, 1919

The conservation movement, initiated during the time of Gifford Pinchot and Theodore Roosevelt, has gradually taken hold of the popular imagination of the American people; and today, although it is little understood, it is an accepted doctrine. But the subject should not degenerate into cheap and misleading publicity. In the wise development and use of human and material resources lies the answer (Fig. 4). Conservation does not mean the parsimonious and misguided avarice of the miser, but the prudent and intelligent use of all types of resources, and the opening of a way for the use of those potentialities that lie just beyond the horizon and wait for man's constructive efforts to make them available. Conservation consists essentially in not emptying the pools of primary wealth before the minds of men, guided by ingenious research, have found ways to replenish them from sources as yet untapped. To advance successfully along this path, man should be guided by science and by a decent understanding of his obligations to his fellow man and particularly to his children and his children's children. Two pathways branch from this general road. One is the restraining of those spendthrifts who would throw away our national heritage for the sake of a cheap and irresponsible enjoyment of the present. Conservation in the generally understood sense usually has meant

Jan 1, 1950

By Bernard Kopelman

THE particle size of tungsten metal powder used to make tungsten wire for use in radio tubes and incandescent lamps must be closely controlled if the highly desirable feature of nonsagging is to be achieved. Our knowledge of factors affecting the particle size of tungsten powder has been limited by lack of any extensive literature on the subject. There are no publications in the English language discussing this problem in any but the most general terms. In this paper the published experimental information on this subject is reviewed. Based on the published data and some experimental data obtained by the author, a general theory of factors affecting the particle size of tungsten metal powder obtained by reduction of the oxides in hydrogen is offered. The various forms of the tungsten oxides and tungsten metal used in the experiments described were those prepared by com¬mercial processes, so that the experimental results obtained on a laboratory scale would be more directly applicable to actual commercial reduction conditions. The effects of time of reduction, temperature, and concentration of water vapor in the hydrogen were observed by counting microscopically the particle distribution obtained. Such a method is very time-consuming, but the data obtained by this method are more reliable and more fundamental than those obtained by any of the several instruments available for measurement of particle size. REVIEW OF THE LITERATURE Until the year 1912, tungsten powder was prepared commercially by reducing tungstic oxide in the presence of carbon or one of its compounds (such as glycerin or ethylene glycol), usually by firing the mixture in a closed fire-clay crucible. The resultant powder contained about 95 per cent tungsten.1 When reduction of tungsten oxides by H2 was introduced commercially, 2.1 several investigators became concerned with the equilibria between tungsten metal and its several oxides in an atmosphere of hydrogen and water vapor.4-13 While these many investigations were in fair agreement on the equilibria there arose considerable controversy as to the chemical composition of the oxide between W03 and W02, because of very poor agreement on the equilibrium constant of this intermediate oxide reduction reaction. The controversy on this intermediate oxide has been in progress for more than 10o years. Thus Malguti,14 in 1835, decided it was W02.56. In 1857, Riche" proposed the formula W308. Usler,16 in 1865, confirmed the existence of W308 and further proposed W4O11. In 1897, Desi17 agreed upon W308 but also found W5014.

Jan 1, 1946