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By E. C. Bain, E. S. Davenport

When annealed carbon, or low-alloy, steels are suitably heated the ferrite (alpha iron solid solution) and the carbide, of which they are composed, react together to form a single solid solution of carbon (and other elements) in gamma iron (austenite). This reaction may begin only at a certain minimum temperature called the eutectoid temperature. The first ferrite and carbide thus to react together do so in definite proportions known as the eutectoid composition. With further heating the original constituent that is present in excess is dissolved in the austenite until exhausted. Whether the excess constituent be ferrite (hypoeutectoid steels) or carbide (hypereutectoid steels) the procedure is much the same, and upon slow cooling the homogeneous austenite expels the excess of either (proeutectoid ferrite or carbide) until the eutectoid composition is reached. Thus the reaction upon heating is strictly reversed upon cooling and accordingly an equilibrium diagram of this process may be constructed. Such an equilibrium diagram concerns itself only with the temperatures involved and with the proportions and compositions of the phases developed under conditions that suffice to permit equilibrium. Specifically it has no concern for the type or mode of distribution of these constituents nor with any extra-equilibrium conditions such as undercooling, which is almost universally encountered in metals. Actually, however, of great importance is the sluggishness toward equilibration caused by the not inconsiderable time involved in diffusion. Thus instead of the theoretical transformation point AF, we find for a certain rate of heating or cooling the use of the designations Ar and Ac (transformation temperature found on cooling and upon heating). These figures obviously have no particular meaning except as measured and expressed for a definite heating or cooling rate, and represent the apparent temperature displacement caused by an inadequate time allowance. In this paper are presented the results of a study of the time required for the transformation of austenite to ferrite and carbide at a variety of temperatures and also of the time required for the reaction austenite? martensite at the temperatures at which this reaction occurs instead of

Jan 1, 1930

By C. A. Heiland

I. Description of reflection equipments.................. 412 A. Design features of present types.................. 412 B. Reflection equipment designed by writer.............. 418 11. Characteristics of reflection seismographs............... 421 A. Types of coupling in electromagnetic seismographs.......... 421 B. Action of pickup, amplifier and galvanometer............. 424 C. Combined action of pickups, amplifiers and oscillographs....... 433 D. Static and dynamic constants................... 434 E. Desirable values for static and dynamic constants.......... 435 111. Calibration of reflection apparatus.................. 442 A. Dynamic tests without shaking table................ 442 B. Calibration methods....................... 445 C. Various other tests........................ 451 INTRODUCTION In the past five years, the reflection method of seismic prospecting has been developed to a high degree of perfection. Its success in mapping oil structure is due to the unique and definite nature of the depth data obtained. While articles on the principle and results of this method continue to appear in increasing number, there is virtually nothing published about the instruments used in this work. Several years ago, the writer started an experimental and theoretical investigation with the object of determining which characteristics would be best adapted to the problem at hand. As a result, an equipment was developed which has proved its usefulness in a great number of field tests. W. E. Pugh, now with the Empire Oil and Refining Co., joined the writer, in 1931 and 1932, in the laboratory experiments and field tests. In 1933, a paper was written on Certain Instrument and Field Problems in Reflection Seismology, and submitted to the Institute. The part of that paper dealing with field tests was published as Contribution 34 (reprinted in this volume, p. 455). Since then, considerably more labora-

Jan 1, 1934

By B. A. Eaton, R. H. Jacoby

This paper presents the depletion-performance correlations developed using data from PVT studies and well-completion tests of 27 rich gas-condensate and volatile-oil reservoir fluids. The PVT behavior for each fluid war determined experimentally in the laboratory, and the depletion performance of each fluid was then calculated. Well-completion test data consisting of reservoir pressure and temperature, initial total gas-oil ratio, and stock-tank oil gravity were used with the depletion-performance data to develop general performance correlations. Three correlations are presented. The first equation shows the empirical relation of gas in place per barrel of hydrocarbon pore space with reservoir pressure and temperature, and initial total gas-oil ratio. The second equation is the correlation of stock-tank oil in place per barrel of hydrocarbon pore space. The third equation relates stock-tank oil production (to 500-psia depletion pressure) with pressure, temperature and oil gravity. All three correlations are also presented in convenient graphical form. Gas production to 500-psia depletion pressure is approximately 92.6 per cent of the gas in place for each fluid, so no correlation was developed for gas production. INTRODUCTION The rate of discovery of shallow, low-pressure and low-temperature oil reservoirs in the United States has been declining in recent years. For this reason, the search for oil has gone to greater depths where high pressures and temperatures are encountered. A high-pressure and high-temperature reservoir is the environment in which many rich gas condensates and highly volatile oils are found. Because of this trend, the performance prediction of such reservoirs has become an important task of the reservoir engineer. The need and usefulness of a performance correlation based on field data that are available from the usual well-completion tests have previously been established. These earlier attempts have shown that the phase behavior of rich gas-condensate systems and volatile-oil systems can be correlated with fluid properties, pressure and temperature. However, very little information on gas-condensate depletion performance5 was available at the time of these earlier attempts. The availability of more recent data has made possible the development of an improved correlation. The data, as listed in Tables I and 2, are for 25 gas-condensate and two volatile-oil systems that were studied. The problem was to correlate the data for in-place fluids and the production data with the initial total gas-oil ratio, initial reservoir pressure and temperature, and stock-tank oil gravity. These correlations were obtained by multiple regression analysis, whereby the data were fitted to an equation by the method of least squared error. BASIS OF THE CORRELATIONS 1. The data used in the development of these correlations were obtained from depletion-performance calculations6 and well-test or production measurements. 2. All of the independent variables used in the correlations are available from the usual well-test completion data. 3. The reservoir volume considered is 1 bbl of hydrocarbon pore space (HCPS). 4. The gas-oil ratio used is the total standard cubic feet of gas (at 14.7 psia, 60F) coming off the entire separator train per barrel of stock-tank oil. This minimizes the effect of separator conditions which might vary from system to system. 5. The correlated pressures are the actual reservoir pressures which might or might not be the saturation pressure of the reservoir fluid.

Jan 1, 1966

By E. T. Turkdogan

This paper deals with an analysis of the conditions leading to the formation of blowholes and surface and subsurface defects in cast low-carbon steels. The theoretical analysis of the problem is based on the concept of the occurrence of deoxidation reactions during cooling of liquid steel and during its solidification. The reaction equilibrium data are given on deoxidation of steel by carbon, silicon, and manganese. The details of the calculations are given on the simultaneous deoxidation of steel by silico-manganese additions to produce a desired level of deoxidation at certain residual concentrations. Based on an idealized model, an attempt is made to calculate the enrichment of solutes in the solidifying liquid entrapped within the interdendritic cells which are known to be less than 200 µ thick. Formulae are derived for the calculation of the change in the residual oxygen content of the enriched liquid steel, controlled by Si/Mn deoxidation. It is shown that for every particular initial silicon, manganese, and oxygen concentration in steel (as residuals in liquid solution at the beginning of solidification) there is a particular carbon concentration below which carbon monoxide, leading to blowholes or pinholes, is not expected to form. There are a number of independent variables which have a decisive influence on the formation of blowholes. For example, it is shown that the position of the curve depicting the critical relation between initial silicon and carbon content for suppression of the evolution of carbon monoxide) can be shifted to lower silicon or higher carbon levels by: increasing manganese content; decreasing oxygen, hydrogen, or nitrogen content; or increasing external pressure on the solidifying mass. FOR the production of sound castings it is essential to prevent the formation of interdendritic worm-holes or pinholes brought about by gas evolution during solidification. Another major problem encountered in solidification of ingots is the formation of surface defects. These problems are thought to be closely associated with the deoxidation reaction occurring in liquid steel during cooling and subsequent solidification. As the liquid becomes richer in impurities during dendritic solidification of steel, a series of reactions may occur in the liquid phase trapped within the branches of growing dendrite platelets. Because of the strong interaction between dissolved oxygen and impurities in liquid steel, the reactions most likely to occur are of the deoxidation type. However, inherent to the extreme complexity of the problem in question, numerous simplifying assump-

Jan 1, 1965

By J. E. Pogue

That the domestic consumption of gasoline displays a marked seasonal variation, with a low in the winter and a high in the summer, is well known. It is logical to expect that the nature of the variation has itself been undergoing a change as a result of improvement in roads, general employment of closed cars, and growth of mass haulage; but so far as I am aware the change in seasonal variation has never been investigated and measured. It is the purpose of this paper to present the method and results of such an investigation, undertaken as a contribution to the technique of planning operating schedules now so prominent in connection with the functioning of the industry under a Federal quota system. For the method employed I am indebted to the suggestions and help of Frederick R. Macaulay,1 who kindly looked over the work sheets; and

Jan 1, 1934

By John D. Vincent, Howard W. Jacky

This chapter covers the normal problems encountered in the building of an ore concentrating facility. To produce such a facility In today's environment requires correlation by the engineers involved of geologic data, mine planning, scheduling, future planning, water resources, power, land availability, testing, design, start-up and environmental considerations. Of course, the program scheduling and character of the ore will determine the weight given to the above considerations in the final design and construction of the plant.

Jan 1, 1978

By F. W. Bloecher

D ETERMINATION of the surface area of finely divided minerals is of interest to mineral engineers engaged in flotation, comminution, and dewatering studies. In the industrial minerals field, many materials are classified as to fineness according to their specific surface (surface area per unit weight). A method of surface area determination has been tested and used in the Richards Mineral Engineering Laboratories at M.I.T. It involves low temperature krypton adsorption measurements using the technique described by Beebe.1

Jan 3, 1951

By Alexandre Mitinsky

The theory of elasticity, the science of the strength of materials, and all our calculations regarding engineering structures are based on Hooke's law, that in loaded bodies the deformations are proportional to the load producing them. Without this law it would be impossible to design intelligently engineering structures such as bridges, frames, axles, etc. This being the case, the proportional limit,l that is, the point at which deformation ceases to be proportional to load, is the most important factor in engineering design. Further, the working fiber stress should be fixed in reference to the proportional limit instead of, as is usual, in reference to the ultimate strength. The incorrect use of the ultimate strength instead of the proportional limit in setting the working fiber stress is probably due to two reasons: (1) it is a more delicate operation to measure the proportional limit; (2) it is usually assumed, though incorrectly, that the proportional limit is determined by the ultimate strength. In Germany the poin't at which permanent set first appears is often taken instead of the proportional limit. The two points will coincide if Gerstner's law, that elastic deformations are proportional to the loads producing them both before and after permanent set, is true; and the limit of proportionality and the elastic limit or point of permanent set will both be represented on a stress-strain diagram, by the point at which the line ceases to be a straight line and becomes curved or changes its inclination. It is to be further noted that the difference in definition between proportional limit and elastic limit introduces a difference in methods of determination in the testing laboratory. The German method of determining the elastic limit by alternately loading and unloading the test specimen is a lengthy process and time has in itself a very considerable influence on the results of physical tests.

Jan 1, 1916

By John Chapman, J. C. Vaughan

Although a considerable amount of practical importance attaches to systems involving gases and molten metals, little is known regarding the effects of alloy elements upon the solubility of gases in liquid iron. The solubilities of hydrogen1 and nitrogen2,3 in pure liquid iron arc known and it has been shown that small amounts of silicon and aluminum3 exert only a small effect upon the solubility of nitrogen but greatly increase its rate of solution. This paper presents the results of a study of the solubility of nitrogen, at pressures approximately one atmosphere, in molten iron containing up to 15.8 per cent silicon. EXPEBIMENTAL METHOD There are two general methods by which the solubility of a gas in a molten metal may be determined. In the first, which Sievertsl employed, the gas is measured from a burette into the enclosure containing the metal and the amount absorbed is found by subtracting from the total volume that of the dead space in the container. The second method, which was used successfully for pure liquid iron, is to expose the molten metal to the gas until absorption ceases, then to solidify and analyze the metal. In either method the stirring produced by inductive heating prevents the development of a stagnant layer at the metal surface and ensures actual attainment of equilibrium. Obviously the second method is accurate only when the saturated metal is capable of solidifying without gas evolution. Since the rate of solution of nitrogen in iron is increased by the presence of silicon, it was to be expected that the rate of evolution would be correspondingly increased and for this reason the first method was selected. A sketch of the furnace is shown in Fig. 1. A small high-frequency coil having 17 turns fitted closely around a fused silica tube, 2 in. in diameter, in which was placed, on a bed of 60-mesh alumina sand, an

Jan 1, 1940

By E. Hornbogen, R. C. Glenn

Copper precipitates from a iron as fcc E phase without formation of intermediate compounds. In the first stage of the precipitation, spherical particles with diameters < 100A are formed at a high rate. During the second stage, the particles grow at a rate given by Zener&apos;s equation for growth of a spherical precipitate. In the third stage, growth is slower. Rod-shaped particles form after long aging times at 700°C. Maximum strengthenzng was observed at the beginning of the second step of precipitation. During plastic deformation of the aggregate, particles appear to deform initially by twinning. THE work discussed herein was part of a study of precipitation of substitutional elements from a iron. Copper was chosen as one of these substitutional elements because it has about the same atomic size as a iron, and does not form an intermetallic compound with iron. The data on the iron-copper system then available were summarized by Daniloff1 several years ago. The solubility of copper in a iron has been determined by electrical conductivity measurements,2 lattice parameter measurements,3 and by saturating thin iron foils with copper and determining the copper content.4 The results of the three investigations do not agree very well, but the value of 2.4 wt pct for the maximum solubility at 840°C seems to be the most reliable,4 Fig. 1. An alloy containing 1.23 wt pct Cu was used in our work to assure starting with a completely homogeneous material. On the copper-rich side of the diagram, there is a maximum solubility of about 4 wt pct Fe in copper at 1094°C ( phase). The precipitation of

Jan 1, 1961

FRIENDS of the late Charles F. Rand presented in 1930 a sum of money from which the income is available to support various phases of the work of the Institute in which Mr. Rand was so deeply interested. At present the fund amounts to $10,400. The specific terms of the deed of gift are as follows: "The fund collected to establish a memorial to the late Charles F. Rand shall be placed in the custody of the Board of Directors of the American Institute of Mining and Metallurgical Engineers, to be set up as a trust to be known as the `Charles F. Rand Foundation,&apos; the income of which shall each year be applied to a distinct purpose to be decided upon in that year by vote of the Board of Directors. This purpose shall be such as to promote the general welfare of the Institute and to constitute a permanent memorial of the usefulness of Mr. Rand, who for many years gave unstintingly of his time and talents in its service. "It shall be within the discretion of the Board of Directors to establish a medal to be known as the Charles F. Rand Memorial Medal to be awarded at such a time and under such rules as may be determined by the Board of Directors, for Distinguished Achievement in Mining Administration." The establishment of this medal was announced at the annual meeting in February, 1932, the term "mining" being defined in its broad sense to include metallurgy and petroleum. Robert Linton is chairman of the Charles F. Rand Foundation Award Committee.

Jan 1, 1944

By J. C. Vaughan, John Chapman

Although a considerable amount of practical importance attaches to systems involving gases and molten metals, little is known regarding the effects of alloy elements upon the solubility of gases in liquid iron. The solubilities of hydrogen1 and nitrogen2,3 in pure liquid iron arc known and it has been shown that small amounts of silicon and aluminum3 exert only a small effect upon the solubility of nitrogen but greatly increase its rate of solution. This paper presents the results of a study of the solubility of nitrogen, at pressures approximately one atmosphere, in molten iron containing up to 15.8 per cent silicon. EXPEBIMENTAL METHOD There are two general methods by which the solubility of a gas in a molten metal may be determined. In the first, which Sievertsl employed, the gas is measured from a burette into the enclosure containing the metal and the amount absorbed is found by subtracting from the total volume that of the dead space in the container. The second method, which was used successfully for pure liquid iron, is to expose the molten metal to the gas until absorption ceases, then to solidify and analyze the metal. In either method the stirring produced by inductive heating prevents the development of a stagnant layer at the metal surface and ensures actual attainment of equilibrium. Obviously the second method is accurate only when the saturated metal is capable of solidifying without gas evolution. Since the rate of solution of nitrogen in iron is increased by the presence of silicon, it was to be expected that the rate of evolution would be correspondingly increased and for this reason the first method was selected. A sketch of the furnace is shown in Fig. 1. A small high-frequency coil having 17 turns fitted closely around a fused silica tube, 2 in. in diameter, in which was placed, on a bed of 60-mesh alumina sand, an

Jan 1, 1940

By Edward D. Peters

IT frequently occurs in the establishment of reduction works, in an entirely new and untried mining district, that the metallurgist in charge finds considerable difficulty in determining the process best adapted to the ores which he receives for treatment. At the first glance it would seem easy enough to decide what style of furnace is best adapted for beneficiating any one class of minerals. If the ore possessed a quartzose gangue and was comparatively free from base metals, while salt could be obtained at a reasonable price, one would naturally resort to a chloridizing roasting, and pan or barrel amalgamation for the extraction of its silver contents. If galena or carbonate of lead was the prevailing mineral, and charcoal could be obtained at moderate figures, the blast-furnace would beneficiate the ores most advantageously. But if, as is usually the case in Colorado, the ores consisted of an intimate mixture of galena, zinc-blende, copper-pyrites, and noble silver minerals, associated with an overwhelming mass of siliceous heavy spar, or limestone gangue, the common reverberatory furnace can be used to the greatest advantage; and, although the product is only a copper matte, I do not hesitate to affirm that it can be treated, and the silver, gold, and copper produced at nearly the same price for which silver and lead can be separated. In Germany, blast-furnaces are frequently used for this same purpose, both for argentiferous and non-argentiferous copper ores ; but any one who will take the trouble to examine the statistics of smelting at Fahlun, the Oberharz, and other Continental works of this description, will see that the expenses are far too great, and the production much too small to think of employing this method in our mining districts, where only the softest and most miserable kind of charcoal is obtainable. I propose in this paper to give an accurate account of the expenses incurred at the Mount Lincoln Smelting Works in treating the same kind of ore, and producing the same end-product in both blast and reverberatory furnaces. I have taken for comparison a favorable campaign of the blast-furnace, and a good average month&apos;s running of the reverberatory. In the blast-furnace estimate I have included the calcining and concentration of the matte produced during that campaign, as I always, when possible, concentrated the regulus made

Jan 1, 1874

By H. Evans, L. A. Hunt

The raw materials used in the blast furnaces at the Geneva Works of U.S. Steel Corp. have a high degree of variability in size-consist and chemical content. To overcome the problems caused by the use of highly variable raw materials in the blast-furnace operation, large blending piles are used. An investigation of the blending system showed that variability was significantly reduced by the use of these blending piles. This paper describes the blending system, the method used to evaluate the effect of the blending system, and the results of the investigation. The remarkable improvement in blast-furnace performance since World War II has been in large measure due to the use of beneficiated burdens to reduce the variation of both chemical analysis and size consist. This practice allows the operator better control of his blast furnace, enabling him to operate more economically and to produce chemically uniform hot metal. Planning for uniformity usually begins during mining by extracting ore from several locations within a pit to produce a final product with a specified analysis. Another approach is to stockpile ores having widely varying analyses in individual piles and then drawing the required amounts from each stockpile to provide a blend with a predetermined analysis. A further improvement in blending procedures is to take ores from several sources, bedding them horizontally in layers and reclaiming by vertical slicing from the blended pile. The last procedure, when properly executed, is one of the best methods for achieving maximum uniformity with highly variable ores. U.S. Steel Corp.&apos;s Geneva Works initially obtained iron ore for their blast furnaces from the Cedar City area of southern Utah. These ores were formed primarily by the replacement of limestone and siltstone formations with solutions containing iron and several other elements. The original iron content of the ores in the ground varied from a high of 70% to practically zero with a minimum acceptable iron content for shipping of 37%. Substantial amounts of silica, calcium, magnesium and alumina were found in the ores along with minor amounts of copper, lead, zinc, nickel, titanium, manganese, phosphorus and sulfur which were sometimes present in detrimental amounts. Iron-to-silica ratios varied considerably throughout

Jan 1, 1968

By A. J. Jacobs, G. Katz

MANY of the studies of intermetallic compounds containing uranium were performed during the early 1940&apos;s under the aegis of the Manhattan Project. Subsequently, much of this work was declassified and published after 1949. In some instances this early work, completed with relatively impure materials, represents the only source of X-ray diffraction powder data available in the literature. In the case of the intermetallic compound U,Fe some discrepancies in the powder pattern exist in the literature. Since this compound has been prepared in this laboratory, it is believed that the publication of the indexed powder pattern would help clarify the conflict in the literature. In studies of the U-Fe system, Gordon and Kauf-mannl and Grogan and Clews2 independently reported the intermetallic compound U,Fe in 1950. The crystal structure was described by Baenziger, Rundle, Snow, and Wilson3 in 1950. It is isostructural with U,Mn, U,Ni, and U,Co and crystallizes in a body-centered tetragonal lattice. The lattice constants determined by Baenziger et al. are: giving an X-ray density = 17.7 g cm-3 for 4 mol per unit cell. The compound used in this study was prepared by melting a stoichiometric mixture of the constituent metals in an argon-arc furnace using a nonconsum-mable tungsten electrode. Before the argon of 99.98 pct purity was introduced into the furnace, it was passed through CaC1, to remove water vapor and afterwards through a stainless steel tube containing calcium turnings heated at 600°C for the removal of nitrogen and oxygen. The purity of the uranium used was better than 99.9 pct and that of the iron was 99.97 pct. Before and during melting a zirconium getter was used to further purify the argon atmos-

Jan 1, 1962

By E. W. Gieseke

Coal preparation men today are confronted with problems brought about by changing feed characteristics. The size consist of the coal going to preparation plants has been getting finer and finer. In order to handle these sizes economically, operators are turning to Notation. American Cyanamid Co., in an effort to enable coal flotation plants to produce efficiently at maximum quality and capacity, wnducted experiments which demonstrated that synthetic flocculants are useful for increasing the capacity of coal and refuse filters and for clarifying coal and refuse slurries, and a wetting agent is beneficial in reducing the moisture content of filter cake. Coal preparation men are today confronted with problems brought about by the changing coal markets, changing feed characteristics, and ever increasing labor and supply costs. Small mines are finding it difficult to exist, and the larger mines are rapidly converting to fully mechanized and automated operation to survive. The size consist of the coal going to preparation plants has been getting finer and finer, and the problems facing the preparation plant personnel are growing larger and larger. Facilities can be provided to handle this plant feed in new plants, but the problems are generally not so simple in existing plants where equipment must often be used to perform tasks far beyond its rated capacity. In addition, various state conservation departments, water commission boards, and other Federal and state agencies are endeavoring to eliminate stream pollution. These problems, and many more not mentioned, have been forced on the preparation engineer for reasons of economy and the public interest. In the matter of stream pollution, a determined effort is being made by the coal industry to cooperate with the Federal, state, and local agencies. Economists predict it will be necessary to produce 600 million to 700 million tons of coal by 1970. Bear in mind that the greater proportion of this increased tonnage will have to be processed in existing plants, and you get an idea as to the problems facing the preparation engineer. Methods presently in use for preparing fine coal do an acceptable job down to 48 to 100 mesh. A very large percentage of the - 48 or -100 mesh fraction of the tonnage of coal produced now is being sent to settling ponds or sold at a low figure for reason of quality. This has caused operators to turn to flotation. Building settling ponds and impounding fines is a costly and, at times, impossible method of handling these sizes. Recently a number of flotation plants have been installed to beneficiate material finer than 48 mesh, and these plants have demonstrated that flotation can be successful and increase the plant realization. Coal is a low cost commodity and processes for its beneficiation must be low in cost. Flotation is such a process. It is easily adapted to handling fine coal, requires very little supervision when properly installed, and is economical to operate. Flotation separates coal from refuse and fine clay. For reagents, several combinations are used. Some

Jan 1, 1962

G. R. GOHN. l-1n Table I11 of The Sager, Brown, and Mears paper, which was presented on the screen, data were given showing the results of accelerated corrosion tests of certain magnesium alloys. Mention was made that these were carried to a certain time which was used as a measure of failure but no mention was made as to the period of time. I would like enlightenment on that. G. F. SAGER (Author).-In reply to Mr. Gohn&apos;s question regarding the times of exposure for the accelerated stress-corrosion tests referred to in Table I11 of our paper, which shows the correlation between accelerated and atmospheric stress-corrosion tests on magnesium alloys, I can say that we usually run the accelerated tests on such alloys for at least 500 hr. We feel that this is long enough to reveal any marked susceptibility to stress-corrosion cracking. In the case of the atmospheric tests on such alloys, we have not yet decided how long we should expose the specimens. Most of them are being exposed for indefinite periods and a good many of our specimens have now been exposed for several years. We may want to continue some of the tests for five or ten years. The period of six months mentioned in connection with the times of exposure for the atmospheric specimens was a rather arbitrarily selected minimum time for which specimens had to be exposed before we counted them with those that had not failed. A fairly large number of magnesium- alloy specimens have been exposed in the atmospheric stress-corrosion tests at var-

Jan 1, 1945

By J. M. Uys, T. B. King

The solubility of water in silicate melts of various compositions was measured. The basicity of the silicate did not appreciably affect the water solu-bulity at low-base content (acid compositions). Near the orthosilicate composition the solubility increased with basicity for silicates in which the cation displayed a weak ion-oxygen attraction and apparently decreased for those in which the cation showed a strong ion-oxygen attraction; metasilicates of the former class dissolved more water than those of the latter. Temperature had little effect on water solubility. The experimental results are interpreted on the basis of two modes of solution, the contribution of one decreasing, and that of the other increas -ing, with increased melt basicity. In the former, solution occurs through interaction with doubly-bonded oxygen atoms and in the latter, through interaction with singly-bonded oxygen atoms, or, in very basic melts, through reaction with free oxygen ions. THE hydrogen content of a steel melt is in a large measure determined by water dissolved in the slag. In some glasses water may be a major cause of "seeds". Water vapor in the furnace atmosphere is the primary source in both instances. A knowledge of the mechanism of water solution in silicate melts should help in assessment of practical methods for its control in steelmaking and glass refining. Walsh et a1.l measured the water content, expressed as hydrogen, of 40 pct lime-20 pct alumina-40 pct silica and 62 pct manganese oxide-38 pct silica melts as a function of the steam partial pressure, in equilibrium with the melt. Tomlinson 2 and, also, Russell3 investigated this relationship for a molten 30 pct soda-70 pct silica glass. In all three investigations, the solubility of water was found to be proportional to the square root of the partial pressure of steam. Moulson and Roberts 4 confirmed this relationship for a silica glass. On the basis of the square root relationship, Tomlinson2 and Russell3 interpreted the solution reaction as "network-breaking", similar to that expected on the addition of metal oxides to silica. Walsh et al.&apos; postulated two possible modes of solution, one the mechanism suggested by Tomlinson and Russell and the other the reaction of the water molecule with an oxygen ion to form hydroxyl ions. These two modes of solution suggest opposite effects of melt basicity on water solubility. However, little appears to be known about the effect of melt basicity on water solubility. Walsh et a1.l found, in the lime-silica system, that the water content increased slightly with increased basicity. As these authors pointed out, this does not appear to be in accord with their further observation that slags containing little or no silica dissolve very little water. Kurkjian and Russell5 measured the effect of basicity on water solubility in alkali silicates in the composition range 15 to 45 mole pct alkali oxide. They found a minimum in the water content at about 25 mole pct alkali. This was interpreted on the basis of two concurrent solution reacZions; one in which solubility was proportional to the activity of doubly-bonded oxygen and, in the other, proportional to the activity of singly-bonded oxygen. The present work was aimed at establishing the effect of basicity on water solubility in silicate melts over as wide a range of compositions as practical. APPARATUS AND EXPERIMENTAL PROCEDURE The silicate melt was equilibrated with a "carrier-gas" of accurately known water content, quenched, and analyzed for water by a vacuum fusion technique. Some pertinent details of the equilibration procedure, analysis technique, preparation, and handling of the silicates are given below. Gas-Silicate Equilibration. The apparatus used to equilibrate the melt with the gas mixture was similar to that used by Walsh et al.&apos; but with some important modifications.6 Purification trains were provided for nitrogen and hydrogen; whenever air or oxygen was used as carrier gas the nitrogen purifiCation train was used with the copper furnace at room temperature. Gas flow rates were measured with capillary flow meters; bleeders filled with a mixture of dibromo and tribromo ethyl benzene (density about 2 g per cc) were used for convenience in controlling flow rates.

Jan 1, 1963

By C. E. Lesher

Low-TEMPERATURE carbonization needs no introduction to the literature on coal. This paper will attempt no review of that literature; it tells the story of the commercial development of one of the processes for carbonizing coal at so-called low temperatures, dealing with the technology and economics of the process rather than with the design of equipment. The process used is that covered by the patents of C. B. Wisner, with improvements and changes made by the Pittsburgh Coal Carbonization Co. The important and novel feature of the process is the phenomenon of making the product in ball form (Fig. 1). Melting coal dust into smokeless solid fuel in an apparatus as simple as a revolving cylinder of ordinary mild steel has been proved to be practical. Furthermore, it has been found that the process has a wide application, for by applying a knowledge of why and how this balling action is accomplished, the apparatus can be designed and adapted to treat any coal that has a certain minimum agglutinating property. The operating plant is 20 miles west of Pittsburgh, adjacent to the Champion preparation plant of the Pittsburgh Coal Co. The coal used is cleaned minus 3/8 -in- or finer sizes. The products are low-tem-perature coke, tar and tar products. Present capacity is 7000 tons per month of low-temperature coke and 140,000 gal, of tar. There is no surplus gas for sale, and none of the light oils are stripped from the gas. The coke is marketed in two sizes, 1 to 2 in. and 1 to 6 in., through retail coal dealers for domestic con-sumption in hand-fired furnaces, and for fireplace fuel. The smaller size is bagged by dealers. Crude tar and many distillates and road tars are sold.

Jan 1, 1940

By Bruce A. Kennedy

The place of the young engineer in the mining industry has been the subject of a large number of keynote addresses, magazine articles, and papers in the past year. One of the best of these was the keynote address given by Mr. J. C. Kinnear, Jr. at the Fifth Annual Intermountain Minerals Conference in Vail. Colorado. Mr. Kinnear presented as part of his address the statistics of a Canadian survey Instigated to find out why young engineers and geologists are leaving the mining industry. The results of the survey showed four main reasons for leaving: 1) insufficient money 2) slow promotion 3) lack of association with senior engineers, as well as insufficient opportunity to keep abreast of technological development 4) geographic isolation

Jan 1, 1970