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By Paul D. Merica

DURING the Dark Ages, when metallurgy was practiced by the alchemists, any unusual or disturbing variation in metallurgical operations was ascribed to the, presence, in the metals or ores, of an evil spirit, and it was necessary to exorcise and drive it out "by suitable incantations. In this day of science and of engineering, things still incomprehensibly go wrong in the metallurgist's work shop. The metallurgist is even now not unwilling to lay the blame for many such experiences at the door of something which intellectually- much resembles an evil spirit, "gas in the metal." The presence of gases in his metal, he knows, occasions him many very definite troubles which he can clearly distinguish and diagnose-why may it not be also responsible for those which he cannot so well understand?

Jan 1, 1931

By H. C. Boynton, Albert Sauveur

In the course of some experiments conducted in the Metallographical Laboratory of Harvard University, some interesting facts were brought to light which appear to be worth recording in advance of a more elaborate and exhaustive paper which the authors hope to present to the Institute in the near future. Fig. 1 shows, under a magnification of 100 diameters, the microstructure of the cross-section of a steel bar 1/2-inch square, containing 0.52 per cent. carbon, heated to 1100 degrees C. and cooled slowly with the furnace. Fig. 2 illustrates the structure of the same steel, heated to the same temperature but cooled more rapidly in the air. Both samples were cut from the same bar and heated side by side in the furnace. When a temperature of 1100 degrees C. had been reached, one sample was taken out of the furnace and allowed to cool in the air, while the other was cooled with the furnace. The only difference, therefore, in the treatment of both samples will be found in their respective rate of cooling. This variation in the rate of cooling resulted, as shown

Jan 1, 1904

By J. D. Doherty

That America's great coal deposits eventually will be our principal source of liquid as well as solid fuels is generally accepted. Moreover, the day when synthetic oil from coal will begin to supplement our petroleum supplies does not appear to be far off. The American petroleum industry has not spared effort or expenditure in its attempt to keep pace with the demand for oil, and recent production has exceeded expectations. However, the rapidly rising demand for liquid fuels plus the increasing difficulty of finding and developing the new oil needed even to maintain present production rates make it highly unlikely that oil from domestic wells can fully meet future oil requirements. Therefore, it appears that one or more of the following courses must be followed: 1. Curtail oil consumption. 2. Incr ase imports. 3. Develop new sources such as synthetic liquid fuels. All three courses may well be needed, as it is doubtful that any one of the three alternatives alone can satisfactorily solve the problem indicated by the prevailing trend in demand for oil. Curtailment of oil consumption is not a constructive policy, except where oil is being wasted or coal can be readily substituted as in stationary steam plants. Reduced oil supplies for most uses will curb our economic advancement and, in addition to inconveniencing consumers, will have a pronounced adverse effect on American industry. The oil-burner-manufacturing industry already has been dealt a hard blow. Shipments in the first 5 months of 1948 decreased 70 pct from those in the same period in 1947.1 The effect of a similar cut in the automobile industry can be imagined. A severe prolonged shortage of gasoline could seriously disturb our present economic well-being. It might be pointed out also that even the prospect of a shortage or lack of assurance for the future can discourage buyers of equipment, as occurred in the case of oil burners. An increase in our imports of oil seems to be a necessary expedient for the immediate future. Its advantages are that it will require a minimum of manpower and steel in a time of critical shortages and will conserve domestic reserves. Any major dependence upon foreign sources for our oil supplies should be avoided, however. Other nations are increasing their oil consumption more rapidly percentagewise than the United States and eventually will compete with us for the not unlimited world supplies. In peacetime, foreign countries might restrict ship- ments of oil to this country or impose exhorbitant prices. In the event of war, there is serious danger that such sources would be cut off, and American-developed oil fields overseas might even be used against us. Although synthetic fuels cannot relieve any oil shortage that might develop within the next year or two, an immediate start toward a substantial synthetics industry to supplement petroleum not only could help relieve shortages several years hence but also would help establish the much needed "know-how" for large-scale production. By assuring ample future supplies, such a start would permit sound planning by industries dependent upon oil and maintain or restore the confidence of prospective customers for oil-con-suming equipment. If it is agreed that domestic production of crude oil cannot be expected to meet future domestic demands, that oil rationing in general is undesirable. and that too great dependence on foreign oil should be avoided—and the weight of the evidence supports such conclusions—it is inescapable that commercial synthetic fuel production should be developed to supplement domestic petroleum supplies, which, of course, will furnish the bulk of our requirements for yean to come. Sources of Synthetic Oil The three principal sources of synthetic oil are natural gas, oil shale, and coal. A commercial plant using natural gas is under construction, and expansion of this industry is expected.

Jan 1, 1950

By A. H. Daane, J. F. Haefling

The limits of miscibility in some of the uranium rare-earth alloy systems have been determined in the temperature range 1000°to 1250°C. The solubilities of lanthanum and cerium in uranium are greater than those of the remaining rare earths by a factor of more than two. The solubility of uranium is greater in cerium, braseodymium, and neodymium than in the other rare-earth metals studied. The values found in this study are in qualitative agreement with those which might be expected if the solubility rules of Hildebrand and Scott are applicable. AS interest in nuclear reactors intensifies, many new types of fuels are being suggested in attempts to improve the economics of some of the proposed reactor schemes. To remove some of the difficulties inherent in the use of solid-fuel elements and their reprocessing, many types of liquid-metal reactors have been suggested. One of the more attractive features of several of these reactor concepts is that they include a continuous or semicontinuous process for the extraction of fission products and "bred" fissionable materials from the fuel, utilizing immiscible metal extractants. This would enable a much higher burn-up of fissionable material to be achieved and would present a very attractive economic picture. Several studies have been reported on equilibrium systems in which there exists a high degree of immiscibility between uranium and another metal that might be used as an extractant in such a processing scheme.' Two of these systems in which a high degree of immiscibility exists are those of uranium with the two rare-earth metals, lanthanum, and cerium. Since the rare earths constitute a significant fraction of the fission products, their removal is of prime importance. It is reasonable to believe that this might be accomplished by equilibrating a rare-earth phase with the contaminated uranium fuel in the liquid state. In order to make a more complete study of those systems which would be of interest either as extractants in a liquid-liquid extraction process, or as fission products formed in the fuel, the alloy systems of uranium with lanthanum, cerium, praseodymium, neodymium, and samarium were studied in some detail in the temperature range 1000" to 1250°C; less detailed studies were made with the other rare earths. In addition to being of value to the reactor program, the data obtained in this study should be of help in making a study of the role played by the electronic structures of metals in determining the nature of metallic solutions. The unique electronic structures of the rare-earth elements make them particularly interesting in this respect. EXPERIMENTAL The usual procedure for a solubility determination was to seal equal volumes of uranium and the particular rare earth in a tantalum crucible under an atmosphere of helium; this crucible was then sealed in a stainless steel jacket in an atmosphere of helium. These samples were equilibrated by repeated inverting of the crucibles in a furnace for 15 min at the desired temperature, left in an upright position for 15 min to permit separation of the two phases, and then quenched under a stream of water. In some runs the temperature of the furnace was held 50' to 100°C above the desired quenching temperature while inverting in order to insure good mixing. However, it was found that above 1200°C the crucibles were subject to failure and for these runs the furnace temperature was not raised above the desired quenching temperature. A small amount of tantalum was dissolved in the uranium and the rare earths in these runs, a maximum of 3 wt pct in the uranium phase at 1250°C and up to 1 wt pct in the rare-earth phase at this temperature. On cooling, the major portion of this tantalum precipitated as primary tantalum crystals. Any residual tantalum would probably have a negligible effect on the mutual solubility of uranium and the rare earths in each other. Samples for analysis were cut from each phase with an abrasive cutting wheel; the region near the interface between the two metals was carefully avoided. In the case of the rare earths with melting points above 1250°C no solubility data were taken on the rare-earth phase since this phase could not have achieved equilibrium in a reasonable length of time. (For the same reason no data were taken on the uranium phase below its melting point of 1132°C.) Equilibrium appeared to have been reached in the uranium phase in these cases although the rare-earth phase had not melted. To verify this, samples were melted together in an arc furnace similar to that described by Kroll.2 These samples were sub-

Jan 1, 1960

By R. E. Grace

WHEN an Fe-C alloy, partially reacted to pearl-ite, is quenched rapidly enough to suddenly stop the growth process, it may be expected that any carbon concentration gradients will freeze in situ in the newly formed martensite. A short tempering treatment should precipitate finely dispersed iron carbide particles in approximately the same distribution in which carbon existed during the growth process. Examination with the electron microscope of areas of tempered martensite adjacent to the pearlite-martensite interface should reveal the existence of preferred areas of precipitation. Fig. 1 is an example of an electron micrograph used in this study. Small sections of a commercial steel (0.9 pct C, 1.6 pct Mn, 0.25 pct Si) were austenitized at 945°C in air for 45 min, furnace-cooled to 697°C, iso-thermally reacted to pearlite for 30 min, and quenched into iced brine. Two samples were tempered 5 and 20 min, respectively, in air at 498°C and were subsequently quenched in water. The samples were mechanically polished and etched in 1 pct picral. Collodion replicas were made by the conventional technique; these were shadowed with chromium at about 650' from the horizontal, and electron micrographs were taken at a linear magnification of 14,200X. Prints were made at a magnification of 44,100X. Lineal analysis of the prints was made as a function of the interlamellar spacing and volume percent of iron carbide. Straight lines were drawn into tempered martensite between adjacent lamellae at a distance S/4 or S/6 apart, where S is defined as the interlamellar spacing measured at the pearlite-martensite interface. The volume percent of iron carbide was measured along each of these traces with a "gage length" of S/10. The results of analyses of two samples are shown in Table I. The area included between the S/2 and S distance from the interface could be considered homogeneous within the sensitivity of the measuring technique. This value was used as a proportionality factor to evaluate an arbitrary carbon content of homogeneous austenite, and also as a parameter by which error in measurements could be evaluated. Results of the lineal analysis are shown in Figs. 2 and 3. Fig. 4 shows the statistical nature of the interlamellar spacing for all lamellae measured in this

Jan 1, 1954

By Olaf N. Rove

YEAR 1951 has been bright for the mining geologist. He has arrived after struggling for a generation or two to sell his wares through service to the operator, the mine superintendent, and the manager. But as he establishes himself on the operating front, he is faced with even greater challenges; namely, the development of basic geologic principles governing ore-forming processes and the occurrence and distribution of mineral deposits. These principles are needed to guide his ever-widening search into new areas. He must now stimulate the interest, confidence, and imagination of the mining executive and layman in fostering the research essential to expand rapidly the basic science of geology and its more specific applications to the mining industry. The hallowed time-tested tools of the prospector and the industry are no longer adequate. New basic data, principles, and ideas are needed to guide industry's exploration. The entry of Government into exploration, by lending money to prospectors and operating companies to partly finance exploration, is one of the major events of the year. This was one of the activities for which the Defense Minerals Administration was established in the Department of the Interior. DMA was staffed largely with men from industry, but the Bureau of Mines and the Geological Survey have acted as its technical advisors and have provided its field staff. Since the start of this work in May 1951 to November 19, 1951, the DMA has approved 208 exploration projects while denying 318 others. The contracts involve about eleven million dollars worth of exploration, of which Government's share is about sixty percent. A few contractors have already made discoveries and are into production to repay their loans; others have completed their projects without making a discovery. In November, the DMA was split into two successor units. The Defense Minerals Exploration Administration was set up in the Interior Department to carry out the exploration program. The Defense Materials Procurement Agency was organized as a separate agency to carry out the other functions of the former DMA, as well as general strategic materials procurement. The strategic materials group of the Economic Cooperation Administration was transferred to DMPA in order to centralize the procurement from foreign sources into one agency, although the authority and scope of activities of this group have not been announced as of the middle of December. The DMA-DMEA-DMPA programs are making large demands upon the technical manpower of the Geological Survey and Bureau of Mines. It is still too early to evaluate with confidence the productiveness of this diversion so far as the immediate and long-range effects are concerned. Many of the individuals associated with these programs, as well as others in the industry, are convinced that from a long-range national viewpoint, the regular programs of both the Survey and the Bureau equal or even exceed in importance the current emergency mineral activities of these two agencies. Uranium Uranium continued to be the glamour-girl metal of the mineral industry, and at the request of the Atomic Energy Commission uranium and thorium were included in the DMA exploration program. Industry's intensive prospecting and mining activities in 1950 were further expanded early in 1951 when the Atomic Energy Commission announced an increased price schedule and a new bonus payment

Jan 1, 1952

By AIME AIME

THE papers presented at the geophysics session" on Feb. 17 were concerned largely with three aspects of the science. The first ones dealt with the transmission of elastic waves through the earth, then electrical methods came in for their share of attention and finally, the question of the teaching of geo- physics came up for the first time at these meetings. Also, for the first time, there was a symposium of mining men on the practical value of the new science. The paper (T. P. 267) entitled "Seismic Propagation Paths" was presented by Donald C. Barton in the absence of the authors. It dealt with an investigation of the speed of propagation of seismic waves. The latter travel in a straight line when proceeding at a constant velocity, but if the velocity increases at increasing depths, the line of travel becomes a curve. Under the assumption of the authors this curve is found to be the arc of a circle, and their paper gives calculations for reflected and refracted wave paths under these circumstances.

Jan 1, 1930

By Arthur Hockman, Howard W. Jaffe, Howard F. Carl

THE problem of establishing practical techniques for evaluating natural corundum ores arose from the desire to improve the existing purchase specifications for crystal corundum procured by the Federal Government for stockpiling. Such purchase specifications had been developed for a large number of products, including minerals and ores considered to be critical and strategic because of the country's dependence on foreign sources of supply. It will be apparent to anyone considering the subject of purchase specifications that the determination of whether or not a submittal meets the specifications is a prime consideration. Consequently satisfactory specifications for minerals should not only incorporate physical, chemical, and mineralogical requirements that are practical but should also establish the means by which both buyer and seller can be assured that materials meet stated requirements.

Jan 4, 1954

Jan 1, 1964

By Frederick Laist

THE past year has witnessed no radical changes in methods for the reduction and refining of copper. The Carson litigation was finally brought to a close ant1 the copper smelter is again free to introduce charge into his reverberatory furnaces in whatever manner suits him best. This litigation naturally led to much experimentation with various methods of charging and with various types of bath. In some cases the charge was introduced more or less centrally on a relatively dry hearth and in other cases into a bath of greater or less depth. The results of these furnaces were meticulously compared with the results obtained in side-charger furnaces, and it was apparent that it made little, if any difference how a given furnace \\.as charged so long as care was taken that there was always something in the furnace for the flames to work on. So long as this requirement was complied with, consumption of fuel per ton of charge smelted and tonnage smelted per furnace day remained substantially the same regardless of the method of charging or the depth of bath employed. In some instances the center-charged deep-bath furnaces gave slightly better results than the side-charged particularly with respect to copper losses. The slags of the deep-bath furnaces are generally a little cleaner

Jan 1, 1930

Gentlemen:-I herewith present a report on some of the more important activities of the Institute for the year 1921. The present incumbent took. over the active management of the Secretary's office on the first of July and his, work was facilitated, while becoming acquainted with the routine of the office, by the constant and., kindly assistance of the former, Secretary, Mr. Stoughton, during the following three months, and that no interruption occurred inn its regular and smooth operation is due to him and to the Assistant Secretary, who has always been ready to give the benefit of his experience and assistance. MINING AND METALLURGY Through the efforts of President Ludlow and the generous assistance of one of our members, coupled with the excellent work of Major Barbour, MINING AND METALLURGY has, during recent months, shown constant improvement, which could not have taken place, however, had it not been, for the support given by a number of our contributing members. We have every reason to feel encouraged with respect to the quality of the publication and its cost of production. For the year 1921, the net cost of MINING AND METALLURGY was about fifty cents per member, per annum. Occasional letters are received criticizing the Board for producing this publication, but they are more than offset by letters of approval. When the, full purpose of the publication is appreciated, criticism ceases. The elimination of MINING AND METALLURGY and reversion to free distribution of all papers to all members, whether desired or not, would mean such a heavy additional expense that the number of papers would have to be much curtailed. The generous cooperation of members in sending for only such papers as they particularly desired has saved, the Institute thousands of dollars. A plan is being worked out that will materially assist in securing a prompt distribution to members of all pamphlets dealing with subjects in which they are especially interested.

Jan 2, 1922

By W. A. Schaeffer, M. Albertson

The Yates field is situated in northeastern Pecos County, Texas. Its productive area is about 15,000 acres. Production is chiefly from limestone of Permian age. Depths of wells vary from 1100 to 1800 ft. Initial productions range from a few barrels to 8000 bbl. per hour. The field outlet has always been prorated. Gas-oil ratios originally varied from less than 100 cu. ft. up to 8000 cu. ft. per barrel at allowable production rates. The average ratio was about 500 cu. ft. Fig. 1 shows the structure of the field and the location of the Tippett lease, on which the original experimental tubing work was done. Before the latter part of the year 1929, little actual effort in practice had been given to determination of the conditions under which the highest efficiencies may be realized in naturally flowing wells. For the preceding few years attention had been given to gas-oil ratios and their possible reduction by maintenance of back-pressure by choking at the well head. Some attempts had been made toward reduction of ratio by bottom-hole choking. In late 1929, the Shell Petroleum Corp. started the experimental installation of specially designed flow columns adapted to high-pressure flowing conditions in the Yates field. The objectives in view were the attainment of low gas-oil ratios at low rates of flow and the maintenance of high bottom-hole pressures. All naturally flowing wells should be provided with a suitable eductor string immediately upon completion of the well, so that the benefits of efficient flow will be derived from the beginning. This paper presents a method of tubing for efficient flow and a discussion of some complex factors which influence well behavior. Factors Influencing Gas-oil Ratios Many factors influence the production of gas from naturally flowing wells. The writers believe that in some instances gas control is effected mainly in the reservoir itself, in others in the well bore, and in still others both sets of factors may be significant. Some wells apparently have penetrated productive zones in which practically all of the gas is closely associated with, and mostly dissolved

Jan 1, 1932

Jan 1, 1889

By Daniel C. McLean

Copper concentrates produced by many operations in the United States and South America contain chalcocite (79.9% Cu) as a major component, yet the grades of these concentrates rarely exceed 25 to 28% Cu. Mineralogical studies made by E.P. Cadwell indicated that the low grades were caused by dilution by pyrite rimmed with secondary chalcocite. Laboratory and plant tests proved that concentrates could be significantly upgraded by using a simple, low cost cyanide leaching technique to dissolve the rims and reject the pyrite. The many advantages of this new procedure are cited and the process steps and a typical flowsheet are described.

Jan 1, 1984

By John M. Dealy, Robert D. Pehlke

This note presents a summary of the available literature on activity coefficients at infinite dilution in binary metallic solutions, Table I. These data should prove useful in not only examining the therm-odynamic properties of binary metallic solutions, but also in predicting the activity of a component in a complex alloy. The relationship proposed by wagner1 for expressing the activity coefficient in dilute solution is of the form:

Jan 1, 1963

By R. Casting, J. Philibert, and C. Crussard

APPARATUS described in this paper uses the properties of X-radiation, emitted by substances under electron bombardment, as a means of rapid chemical point analysis. The method is based upon the principles of emission X-ray spectrography pioneered by Moseley in 1913. A very finely focused beam of electrons—the electron probe—is projected on the surface of a sample, which has a very large area compared with the beam diameter, at the point where it is desired to know the chemical composition. The minute volume of the sample which is thus irradiated emits a complex X-ray spectrum consisting principally of the characteristic radiations of the elements present in the volume. Measurement of the wavelength and intensity of each component of this spectrum thus affords a simple method of determining the chemical identity and concentration of these elements. The volume of sample which is analyzed at each position of the beam is limited by the diffusion of electrons in the sample. For an accelerating potential of the electron beam of about 30 kv, which is a convenient value for producing the characteristic radiation, this diffusion extends over a diameter of about 1 µ normal to the beam, and about 2 µ in the direction of the beam. Thus a beam of 1 µ in diameter leads to a volume of about 2 µ in diameter being irradiated. The limits of the analyzed region are thus considerably smaller than those obtained by using spark or arc emission spectrometry, which must extend to about 50 µ at right angles to the beam, and those obtained in X-ray fluorescence analysis, where the penetration of the specimen is considerably greater. The apparatus itself consists of three main parts: an electron optical system. an X-ray spectrograph and an optical microscope. The electron opticai system consists of a tungsten cathode emitting the electrow and a pair of magnetic lenses which focus the electron beam on the specimen to be analyzed. The specimen is prepared in the usual way, as in optical micrography. The X-radiation, emitted at the focal spot where the electrons strike the sample, is analyzed with a curved crystal, Geiger-Müller counter, vacuum spectrograph. The light microscope, designed to observe the surface of the sample in the region to be analyzed, is provided with a reflecting objective placed on the axis of the second magnetic lens. Its magnification is X450. The quantitative determination of an element A in the analyzed region is made by measuring the intensity I, of a strong characteristic line of the element, as emitted from the sample, and then the intensity I (A) of this same line as emitted from a

Jan 1, 1958

By R. E. Tate, F. W. Schonfeld

In 1899, Lebeau1 reported the preparation of the compound Lis As through reduction of lithium arse-nate with carbon. Brauer and zint12 have described the preparation of Li3 As by combining the elements in liquefied ammonia and by melting the elements in a zirconia crucible coated with lithium fluoride. In 1953, at the Los Alamos Scientific Laboratory, LisAs and a previously unreported compound, LiAs, were prepared by the reaction of the elements. PREPARATION OF THE COMPOUNDS Attempts to form lithium-arsenic compounds by

Jan 1, 1960

By Jack C. Bokros, Philip C. Rosenthal

DEVELOPMENT of the autoradiographic method in metallurgical research has been directed mainly toward gaining higher resolution, i.e., toward being able to locate segregation of a radioactive isotope on a finer scale. In the investigation reported, the liquid emulsion autoradiographic technique' used in the biological science was adapted to the autoradiography of metals. The distribution of carbon-14 in pure iron after various treatments was studied using this technique. Amorphous carbon uniformly labelled with carbon-14 at a specific activity of 6.95 microcuries per millimole was obtained from Tracerlab Inc. Carbon-14 emits P particles having a maximum energy of 157 kev and an average energy of about 50 kev. These ßs have a maximum range of about 30 mg per cm' and a half-thickness of about 3 mg per cm2. The iron used was spectroscopically pure electrolytic iron prepared by the Oak Ridge National Laboratory. Unhardened nuclear track emulsion, type NTB, was kindly supplied by the Eastman Kodak Co. This emulsion contains approximately 80 pct Ag halide,

Jan 1, 1957

By R. E. Reed-Hill

Recently Levine applied the Conrad-Wiedersich17 equation where H is the activation enthalpy, v the activation volume, T* the effective shear flow stress, T the absolute temperature, and ? the strain rate, to an analysis of titanium single-crystal data. The activation energy as a function of testing temperaturs obtained from specimens oriented for single (1010) prismatic slip is shown in Fig. 12. This diagram indicates a different linear dependence of H on T in the temperature interval from 220° to 300°K than from 0° to 220°K. Levine interpreted the break in this curve as indicating a change in the thermally activated mechanism controlling the flow stress. The purpose of this communication is to point out that the data in Fig. 1 is not consistent with the concept of a flow stress controlled by a simple thermally activated mechanism between 220° and 300°K. The Conrad-Wiedersich relation assumed that the strain rate can be expressed by:

Jan 1, 1968

By Ellis H. Gates

BENEFICIATION of the manganese oxide ores at Three Kids Mine near Henderson, Nev., has evolved over a period of years. Commercial application of the process is on a secure basis, and an effective working hypothesis has been formulated to help solve the problems encountered in flotation. An outstanding difference between the Manganese Inc. operation and other flotation processes is the necessity for high recovery of slime mineral values. Part of the manganese minerals in the Three Kids ore deposit occurs as primary slime or as minerals that are easily slimed by grinding. High recovery of this slime portion is essential to an economic over- all manganese recovery. The aim of much of the research at Manganese Inc. was to recover these slimed and finely ground minerals by flotation.

Jan 12, 1957