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By G. E. McElroy

THOUGH air jets occupy only a minor role in the ventilation of mines and other enclosures, their importance in this respect is greater than is commonly recognized and may be considerably increased as our conception of their modes of operation becomes clearer. The object of this paper is to discuss some of the ways in which air jets are involved in mine ventilation and some possible applications to the ventilation of mines and other enclosed spaces. The mention of air jets ordinarily suggests the use of some form of an air injector, such as the Venturi blower occasionally used for auxiliary ventilation in mines, or the Saccardo (injector) system used to a limited extent for ventilating railroad tunnels. Actually, the term covers such common phenomena as the discharge of air from fan pipes and coal-mine line brattices, and even from smoke stacks and fans. A knowledge of the general mode of air entrainment by jets also helps to explain certain phenomena-some mine-gas explosions, for instance-that otherwise would remain obscure. Jet action has been involved in three recent series of Bureau of Mines experiments in which the author has participated: experiments on fan-pipe discharge, on the dilution of gases discharged from a stack and on the ventilation of a ship's hold. Available data on the discharge of jets into large openings and on the design and performance of air injectors have been analyzed in considerable detail and supplementary experiments are planned for after the war. The results of the fan-pipe experiments have been combined with the analyses of data on jet discharge into large spaces, and have been published.1 The results of the stack-gas dilution tests, which refer to a jet discharged into a crosswind, have also been published2 and a paper on the design and performance of injectors has been prepared for publication.3 These technical experiments and analyses form the background and the documented evidence for the following nontechnical discussion of the use of air jets in mine ventilation. JET CHARACTERISTICS The jets commonly encountered are those in which the air is in turbulent-as opposed to laminar, or streamline-motion. The characteristics under discussion apply only to such turbulent jets and have their basis in theories of the mixing of turbulent air currents. Such jets have basic characteristics that are present, though variable in form, regardless of whether the jet expands freely in space, whether the expansion is limited by adjacent walls, or whether the jet propels air through a flow circuit. They expand at definite angles and entrain the surrounding air, even though the entrained air must be obtained by recirculation of their own air streams. As the quantity of air in motion in the mixed stream increases, the average velocity of the stream decreases. In the case of entrainment in the free

Jan 1, 1945

By R. V. Wheeler, F. V. Tideswell

The suggestion, which appears to find increasing favor, that the elementary composition of coals should be used as the basis of their classification, makes it important that our methods of expressing this elementary composition should be refined. It is doubtful whether many published ultimate analyses of coals are accurate within 1 per cent. carbon. Many are probably as much as 3 or 2 per cent. in error in carbon. It is, perhaps, not always realized that the extreme variation in carbon content over the range of bituminous coals is but 16 per cent. An error of 1 per cent. in carbon on analysis corresponds therefore with one-sixteenth of the whole range, an amount which is unjustifiable even for the application to commercial needs of a system of classification based on ultimate analysis. For the purposes of scientific research such limited accuracy is of little value. The object of this paper is to examine one important source of error in ultimate analysis, that due to the occurrence in coal of inorganic material, and to emphasize the need for the quantitative measurements (of carbon more particularly) on coals to be rendered independent of their contents of such material. Adventitious Mineral Matter When a determination of calorific value, for example, is made upon a coal, it is customary to correct the measured value with respect to the ash left by the coal on incineration, recording the result as being on an "ash-free basis." It is desirable, before discussing the adequacy of the correction thus made, to demonstrate its validity, which turns on whether the ash is present as an adventitious impurity in the coal and forms no part of the coal substance itself. The inorganic matter associated with coal has originated in several ways1: 1. The "inherent" inorganic materials, occurring as constituents of the plants from which the coal-forming deposits were derived.

Jan 1, 1928

By G. H. Edmunds, C. H. Mathewson

About fifty pages of Henry M. Howe's profound treatise, "The Metallography of Steel and Cast Iron," are devoted to twinning with special reference to the origin, nature and general significance of the Neumann bands in ferrite. Howe believed with Osmond and Cartaud1 that the Neumanns are mechanical twins and his careful observations leave no doubt that these straight-sided narrow bands habitually occur parallel to trapezohedral planes of form {211). Attempts to develop the structure of the bands by various methods SO that their identity could be established beyond question have not been conspicuously successful. Howe thought that they deflected slip bands. Some of the etching figures which have been developed within and adjacent to Neumann bands support the contention that they are twins. A good example of this effect in ferrite containing 0.6 per cent, of niekel and 1.3 per cent. of phosphorus, originally due to Harnecker and Rassow,2 was reproduced in the 1928 lecture before the Institute of Metals Division on twinning in metals.3 In this case, the sides of the figures might represent the traces of cubic planes laid bare by etching a properly oriented grain of ferrite, twinned along a plane of form (211). Our own observations in this direction may be represented by Fig. 1 which shows in a deeply etched cavity in the boundary region between a Neumann band and the original crystal two small crystal surfaces which resemble the faces meeting at a reentrant angle in the simple cube twinned along a bisecting plane of form (211) as sketched in Fig. 2. Rosenhain and McMinn4 in 1925, after a careful study of slip bands in ferrite containing Neumanns previously produced by shock, concluded

By A. M. Ross

DEURING the past year the uranium milling industry has seen the installation and initial operation of solvent extraction circuits in the Climax Uranium Co. mill at Grand Junction, Colo.; the Kerr-McGee Oil Industries mill at Shiprock, N. M.; and the AEC pilot plant at Grand Junction, operated by National Lead Co. Inc. The Vitro Uranium Co. mill in Salt Lake City is converting to solvent extraction, and the new Union Carbide Nuclear Co. mill to be constructed at Rifle, Colo., will also employ this method. Solvent extraction circuits will be incorporated in two mills now under construction -the Texas Zinc Minerals Co. mill at Mexican Hat, Utah, and the Gunnison Mining Co. mill at Gunnison, Colo. In Canada the expansion of the Eldorado mill at Port Radium includes installation of a solvent extraction circuit. Solvent Extraction Process: In simplest terms, the organic solvent is mixed with leach liquor and then the organic and aqueous phases are allowed to separate. By this contact the solvent selectively extracts uranium from the liquor, leaving a raffinate, or barren leach liquor, which may be discarded. The pregnant solvent is stripped of its uranium by con- tact with a stripping solution, such as aqueous sodium carbonate, which has a greater affinity for uranium than the solvent does. The barren solvent from the stripping step is available for further leach liquor extraction, and the pregnant stripping solution, which usually contains 30 to 60 g U3O8 per liter, is ready for precipitation of a final product, or uranium concentrate.

Jan 9, 1957

By R. L. Perrine

This paper shows how stability theory can be used to optimize solvent recovery of oil. Application of the theory leads to definition of the limiting conditions required for stable displacement to occur. One of these conditions is that the size of a solvent "slug" must at least equal a prescribed minimum. The criteria to be satisfied are miscibil-ity and stability. Stability implies that no viscous fingering will occur and that mixing will be caused only by a dispersion process. Miscibility implies that complete recovery will be obtained from the swept regions. Thus, for any specified set of reservoir conditions, an optimum use of solvent is defined. INTRODUCTION The early outlook for solvent flooding as a means to increase oil recovery was very favorable. Some laboratory results indicated that a "slug" containing perhaps 2 to 3 per cent of a hydrocarbon pore volume could be successful. However, other data suggested as much as 30 per cent would be required. The difference is of considerable economic importance. A theoretical explanation for these divergent results has been advanced by the author.1,2 Stability theory defines conditions for two distinct flow regimes. In stable displacement, solvent and oil become mixed by a dispersion process, and the solvent requirement is small. On the other hand, unstable displacement can degenerate into viscous fingering. The practical result is a considerable increase in the extent of mixing and, thus, in the solvent required. The present paper shows how to use stability theory to optimize solvent recovery of oil. Oil is usually considered to be displaced by a small amount, or a slug, of solvent. Gas in turn follows solvent. Any fingering will permit contact of nearly solvent-free gas and oil, leading to immiscibility and reduced recovery. Thus, our optimum is defined by two restrictions — stable flow and miscibility. Although an immiscible solvent process could prove more profitable than any miscible process, such processes lie outside the selected definition of an optimum. The usefulness of computations based on the present work will depend on the validity of the general theory. Because the important idealizations required tend to minimize the predicted solvent requirement, the results should state correctly the limiting conditions required. Therefore, theoretical calculations should have practical value. This paper first reviews several principles that result from stability theory. The following section describes use of these ideas in relatively simple systems which symmetry makes appear one-dimensional. Of particular importance is the step-by-step design of 3 stable minimum-solvent slug. The use of stability theory in cases of multi-dimensional displacement is discussed and, finally, suggestions are given for simplified practical application of the theoretical results. PRINCIPLES OF STABILITY THEORY The use of perturbation methods to derive stability conditions has been shown by the author.l The discussion is presented in terms of the fractional concentration of solvent in the single hydrocarbon phase. Quite generally, any disturbance can be represented as a Fourier series, of which only the least stable term need be considered. Denoting this term at time t = 0 by cn,

By J. G. Bartram

Jan 1, 1934

By M. N., Short

TIE Pioneer mining district, better known as the Superior district, from its principal town, is located in Pinal County in south-central Arizona about 80 miles east of Phoenix and 22 miles west of Miami. The region embraces a confused series of mountain ranges of moderate FIG. I.----SUPERIOR, LOOKING NORTH FROM SOUTH BANK OF QUEEN CREEK. MAGMA MINE IS INDICATED BY WASTE DUMP IN GULCH TO RIGHT OF CENTER. height but precipitous slopes, between which lie irregular valleys filled with alluvial detritus. The average elevation is about 2800 ft. in the valleys and the summits of the ranges reach 2000 ft. above this. Superior is situated on the north bank of Queen Creek where it emerges from one of those ranges into a more or less basin-shaped valley. The drainage of Queen Creek is to the southwest and the flood waters spread out and lose themselves in the desert northeast of Florence, the county seat of Pinal County.

Jan 2, 1926

By James K. Gluck, William E. Galloway, Gary E. Smith, John P. Morton, Christopher D. Henry

INTRODUCTION Surface mining and in situ leaching of uranium have the potential to alter ground-water quality around mines and leach sites. Of particular concern is the fate of uranium and its associated trace elements: molybdenum, arsenic, and selenium. We wish to under- stand the natural processes that control trace element concentrations in ground water and how these processes will influence dispersion of the elements from a mineralized zone, both naturally and during and after mining or restoration. For example, it is commonly recognized that the trace elements are soluble in oxidizing ground water but are insoluble, and can be precipitated, in reducing ground water. Thus oxidizing, metal-bearing water leaving a deposit could re- enter reduced ground, causing the water to be re- reduced and the trace elements to be, reprecipitated. In a sense, this is recreating the original mineralization process. To accomplish the above goals, we have (1) examined the theoretical controls of concentrations based on the available geochemical and thermodynamic data, (2) determined the major ion composition and oxidation-reduction status of Oakville waters because of the influence of these factors on trace element solubility, and (3) determined trace element concentrations and distribution in Oakville ground water. The last approach is used to evaluate how well actual behavior follows predicted behavior. This report focuses on two elements, uranium and molybdenum, because they exemplify the results obtained. The report also is restricted to a regional study of Oakville ground water. Results of more de- tailed study in and around major uranium districts in the Oakville and much of the raw data that support the conclusions in this report are presented in Galloway, Henry and Smith (1980). This report is part of that larger study, which concerned the depositional systems, hydrology, and geochemistry of the Oakville. The U.S. Environmental Protection Agency funded the study, under grant numbers R-805357-01 and R-805357-02. Theoretical controls were determined by reviewing the available literature on aqueous chemistry and behavior of uranium and molybdenum. To aid in under- standing water chemistry, Oakville water analyses were run through a modified version of the computer model WATEQF (Plumer, Jones, and Truesdell, 1976). WATEQF calculates speciation of dissolved ions and determines saturation with respect to a variety of minerals. In the discussion below, ion activity products (IAP) are compared with the equilibrium constant (KT) for various reactions and mineral products. Values of log IAP/KT near zero indicate that the water is in equilibrium with a mineral. Values less than -1 indicate considerable undersaturation and values greater than +1 indicate oversaturation. Galloway, Henry, and Smith (1980) give a more complete discussion of the application of this approach to Oakville water chemistry. Eh-pH diagrams have been constructed or adapted from the literature to predict what form -- dissolved ion or stable mineral species -- uranium and molybdenum assume under various conditions. Construction of the diagrams has followed procedures described by Garrels and Christ (1965). This approach is particularly appropriate because the solubility of the elements is Eh-dependent, and Eh varies greatly within the Oakville aquifer. A number of assumptions or approximations are inherent in the use of Eh-pH diagrams and chemical models such as WATEQF and in the interpretation of water chemistry in general. Both Eh-pH diagrams and chemical modeling rely entirely upon available thermo- dynamic data, including free energies of formation and dissociation constants for various reactions. These values are known to varying degrees of accuracy. Most major ions and minerals are relatively well control- led; however, data for trace metals are much poorer. Thermodynamic data are not available for some minerals, and for other minerals, two or more divergent values exist. By necessity, we have relied on the judgment of others to evaluate thermodynamic data. Calculations by WATEQF and constructions of Eh-pH diagrams are based on an assumption of equi1ibrium. Equilibrium may not be comnon in low-temperature aqueous environments; at best, ground-water composi tion may be in a state of dynamic equilibrium, continuously changing due to changes in environmental conditions. Eh-pH diagrams show what phases are stable at equilibrium under given conditions; they do not prove that the phases actually exist. Many minerals persist or form metastably under conditions outside their equilibrium stability field. The kinetics of reactions, which cannot be evaluated here, are important in determining what phases occur. Kinetics may be less of a problem for ground water that travels and evolves slowly through a semihomogeneous matrix than for many other natural systems. Eh-pH diagrams show equilibrium fields only of phases included. They do not indicate anything about stability relative to phases not included in the diagram. WATEQF, obviously, cannot calculate the degree of saturation of a mineral not included in the program or for which the appropriate ions were not analyzed. Thus, a mineral that was not considered may be the most stable phase under a given set of conditions and may control the solubility of a trace element. Also, this study is limited exclusively to in- organic compounds. Organic material is known to be an

Jan 1, 1980

By W. J. Carlson, I. lwasaki

Manganese and silica in nonmagnetic tailings from the direct reduction-magnetic separation step were so closely associated that no physical concentration methods were effective. Dilute sulfuric acid dissolved manganese and iron rapidly; manganese in the form of silicates was virtually insoluble in sulfuric acid solutions, thereby governing the maximum extraction attained by leaching. Autoclave leaching at elevated temperatures and at high oxygen pressures reduced the iron extraction to less than one tenth without affecting the manganese extraction. There was an indication that autoclaving solubilized the manganese silicates appreciably. Elimination of iron from leach solutions was carried out by aerating the solution in the pH range of 6.5-7; a platinum-calomel electrode pair provided a reliable indicator for the end point of iron removal. The purified leach solutions were free of interfering impurities for the recovery of manganese as metal, dioxide, or carbonate. Manganiferous iron ores of the Cuyuna Range, Minn., are too low in iron content to be directly useful as iron ores, and too low in manganese content to be termed manganese ores. Common methods of physical beneficiation such as gravity concentration and flotation have not been successful in upgrading this material. The R-N process, when applied to manganiferous iron ores,1'2 produces sponge iron by direct reduction of iron oxides, while leaving manganese as manganous oxide. From fine grinding and magnetic separation of the reduced ore, a tailing is produced which is relatively rich in manganese and low in iron content. The nonmagnetic tailing can readily be leached with acids and then further processed to recover manganese in various forms. In this way, two processes, neither of which would be an economic solution to the Cuyuna ore problem by itself, may be combined to produce two marketable products, thereby rendering the over-all process economically more attractive. This article reports on the results of a leaching study on the nonmagnetic tailings, both in a batch agitation vessel and in an autoclave; on the problems involved in the purification of leach liquors by aeration; and on the recovery techniques used to produce manganese metal by electrolysis, manganese dioxide either by electrolysis or by autoclaving, and

Jan 1, 1968

By R. E. Hook, H. J. Garrett, A. M. Adair

X-ray diffraction and metallographic techniques were employed to examine the impurity phases occurring in as-swaged and recrystallized chromium produced fvom high-purity iodide chromium crystals. Chromium oxides are found to form in a consistent manner associated with the temperature of recrystallization. Microscopically observable second phase particles of Cr203 are observed to form intergranulurly beginning at 1300T. Beginning at 1500°C. Cr30, is formed intergvanulurly, atzd at 1600°C and above Cr30, is also formed in association with migrating grain boundaries. Geometrical traces formed by particles of this high temperature oxide uithin the grains rez)eal the histmy of grain boundary motion. X-ray evidence is presented which suggests the existence of a high temperature form of Cr203. Other impurity phases in addition to the oxides of chromium are also present. THE partitioning Of impurity elements between grain boundary aid lattice sires, either as solutes in solution or as second phases, may exercise an important influence on the mechanical behavior of metals and alloy systems. This partitioning of impurities could have a direct bearing on the iecrys-

Jan 1, 1963

By E. H. Cho

INTRODUCTION Activated charcoal has been used for several centuries in many capacities including the recovery, isolation and purification of various materials (1). The first use of charcoal in a gold metallurgical system was in the extraction of gold after chlorination (2, 3,4). The gold was dissolved in a chlorine system and subsequently filtered through charcoal. The application of charcoal with cyanide extraction was patented by Johnston (5) in 1894 and adopted commercially in Australia in 1897. The process consisted of dissolving the gold and silver in a potassium cyanide solution and passing it through a series of charcoal filters. The charcoal was subsequently smelted to recover the gold and silver. The interest in the use of charcoal diminished in the first part of the twentieth century as the practice of the use of zinc as a precipitating agent increased. However, in 1916, the Yuanmi Mine in Australia replaced their zinc precipitation plant with a charcoal adsorption plant. In 1926, Scott and Gross (7) of the U. S. Bureau of Mines con- ducted extensive research on the adsorption of gold and silver from cyanide leach solutions. Among their findings was the result that the most important factor in improving the adsorptive power of charcoal was heat treatment with oxidation by air or steam. The work of Zadra (8) in 1952 stimulated renewed interest in the use of activated charcoal in gold and silver recovery with the development of a method of recovery of the gold and silver from the charcoal other than its destruction by burning. The process involved simultaneous desorption

Jan 1, 1983

By Henry G. Petrow, Edward S. Porter

MAJOR occurrences of lignite with significant uranium concentrations have been reported in western parts of the Dakotas, especially in Harding County, S.D., and Billings and Slope counties, N.D. Samples containing as much as 2 pct U3O8 were received at the Winchester Laboratory, but those deposits reportedly of major significance have generally contained 2 to 4 lb of uranium per ton of lignite. Most of the uranium appears to be associated with the carbon in the lignite as a urano-organic complex, although in most instances analysis of inorganic material has shown uranium values. Molybdenum is similarly associated with the carbon, and its concentrations generally parallel the uranium. The noncarboniferous material is mainly composed of gypsum, jarosite, bentonite, sandstone, and miscellaneous carbonates and silicates. The heating value of these lignites has been determined as about 3500 Btu on a dry lignite basis. The ash content of lignite has varied widely, the important samples containing 30 to 60 pct ash on a dry lignite basis. Because of the significant upgrading of uranium values obtained by ashing the lignite, and because recovery of uranium from raw lignite presented formidable processing problems, major emphasis at Winchester has been placed on devising methods to recover uranium from lignite calcines. Proper roasting removes the problem of organic fouling of solutions, reduces the size of the leaching plant for an equivalent uranium throughout, and generally provides equal or better acid leaching efficiency with less acid than can be obtained from the raw lignite.

Jan 9, 1957

By Richard B. Reese, George R. St. Pierre, Robert A. Rapp

The vapor pressures of pure iron and pure chromium have been measured using a Knudsen cell coupled with a mass spectrometer. The experimental results agree well with some previously reported data; heats of sublimation and vaporization have been calculated. From vapor pressure rr~easurernents, the activities of iron and chromium in their binary alloys have been determined for NcY = 0.10 to 0.65 over a 1400" to 1700~ temperature range. The activity of chromium in the liquid alloys was found to exhibit positive deviation from ideal behavior when referred to solid chromium as the standard state; however, for the activity of chromium referred to nonequilibrium undercooled liquid chromium as standard state, the activity behavior is almost ideal. ALTHOUGH the Fe-Cr system is important as the basic system of alloy steels, the thermodynamic properties of this system have not been thoroughly investigated at elevated temperatures. In view of the potential practical applications of such data as well as their contribution to alloy theory, further study of the Fe-Cr system was undertaken. In addition, further development of experimental techniques for equilibrium measurements at high temperature is required. The present research involved an application of the Knudsen effusion method in conjunction with a time-of-flight mass spectrometer. Belton and ~ruehan' have measured the activities in Fe-Ni and Fe-Co alloys by a similar method. Speiser, Johnston, and lackbburn' have determined the vapor pressure of pure solid chromium between 1283" and 1561°K by a Langmuir free evaporation technique. The vapor pressure of chromium was described by the expression: over the temperature range 1283" to 1561°K. McCabe, Hudson, and paxton3 have measured the vapor pressures of pure iron and pure chromium by the Knudsen cell technique around 1500°K. The vapor pressure and heat of sublimation at O°K, AH,", for pure chromium agreed within experimental error with the measurements of Speiser et al. at 1200°C. Kubaschewski and HeYmer~ determined the vapor pressure of pure solid chromium in the temperature range 1170" to 1400°C by the Knudsen effusion technique combined with a radioactive tracer analysis of crS1. Their results agreed with the work of previous investigators. Edwards, Johnston, and Ditmars5 have measured the vapor pressure of pure solid iron by the Langmuir technique between 1356" and 1519°K. The vapor pressure of solid iron in the temperature range studied was given by: The data of McCabe, Hudson, and paxton3 on the vapor pressure of pure iron around 1500°K by the Knudsen effusion technique were in good agreement with those obtained by Edwards et a~.~ Hultgren, Orr, Anderson, and Kelley give the selected values for the AH: of pure iron and pure chromium as 98,990 *200 and 94,340 * 500 cal per mole, respectively. These values are the average values determined in the several investigations by different methods. The Fe-Cr phase diagram7 is shown in Fig. 1. Previous determinations of activities in this system have been carried out by several investigators, but most of the work has been done on solid alloys. Using a Knudsen effusion method with cr5', Kubaschewski and Heymer4 reported that the Fe-Cr system exhibits positive deviation from the ideal behavior for compositions ranging from NCr = 0.0398 to 0.699 at 1170"

Jan 1, 1969

By A. Eilers

THE telluride of gold and silver, the " Tellurgold-silver" of Hausmann, and " Petzite" of other mineralogists, has been found in so few localities, that a late discovery of the mineral in a new locality may not be uninteresting. So far this mineral has been found in Europe only in a few mines in Transylvania, and in Hungary ; and in the United States in the Stanislaus Mine, in Calaveras County, California, in the Golden Rule Mine, Tuolumne County, California, and in a mine in Montana, the precise locality of which I have forgotten. The new locality referred to is at the Red Cloud Mine, Gold Hill District, Boulder County, Colorado.

Jan 1, 1873

By G. K. Manning, A. R. Elsea, C. R. Simcoe

Boron increases the hardenability of hypoeutectoid steels by decreasing the nucleation rate of ferrite and bainite. It is postulated that concentrations of lattice imperfections, such as exist at the grain boundaries, furnish the necessary energy for nucleus formation. Boron, because of its atomic diameter, will concentrate at lattice imperfections where sites of suitable size are present. Boron will decrease the energy of these local areas by occupying these sites. This mechanism accounts for the large increase in hardenability observed with small amounts of boron. The loss of the boron hardenability effect and the boron precipitate formation are explained on the basis of increased concentration of boron at the grain boundaries either with increasing boron content of the material or with increasing temperature. COMMON alloying elements affect both the nucleation and growth rates of the austenite decomposition reactions.' This effect is largely a result of the slow diffusion rates of these elements. Although a small addition of boron markedly increases the hardenability of steel, the diffusion rate of boron, which is of the same order of magnitude as that of carbon, can hardly account for this effect. An addition of boron in the range of 0.001 to 0.003 pct is about as effective as an addition of 0.30 pct Mo, 0.40 pct Cr, or 1.25 pct Ni in increasing the hardenability of a 0.40 pct C steel;' however, increasing the carbon content of the steel decreases the effectiveness of the boron addition."' The difficulty in understanding why so small an addition of boron can replace much larger quantities of the more strategic alloys, together with the erratic behavior sometimes encountered in boron-treated steels, has interfered with their general acceptance by industry. In the belief that an understanding of the mechanism by which boron increases the hardenability of steel should lead to a more general acceptance of boron-treated steels, a research investigation to determine this mechanism was undertaken at Battelle Memorial Institute under sponsorship of Wright Air Development Center. Experimental Work In order to study the effect of boron on the transformation of austenite to ferrite and bainite, a group of steels was made with a basic composition similar to that of the SAE 8600 series. This base composition was chosen because it has sufficient hardenability to permit accurate measurement of the times required for transformation to start at various temperatures. The chemical analyses of the steels used in the first part of this investigation are listed in Table I. These steels were made as 200 lb heats in an induction furnace. The furnace charge was Armco ingot iron with the alloying elements added as ferroalloys. After the alloy additions were made, the heat was deoxidized with 0.125 pct Al. A 100 lb ingot was cast and an addition of 0.003 pct B, as ferroboron, was made to the metal remaining in the furnace. This metal was cast into a second 100 lb ingot. The ingots were forged to 11/4 in. diam bar stock from which end-quench hardenability specimens were obtained. Part of this material was further reduced by hot rolling to lx¼ in. bar stock from which specimens were obtained for isothermal transformation studies. Studies of Nucleation and Growth: End-quench hardenability tests were performed on these steels, using an austenitizing temperature of 1600°F. The hardenability curves, shown in Fig. 1, indicate that boron treatment resulted in considerable increase in hardenability of the steels. Any such change in hardenability must result from a change in the transformation rate of the austenite, and these rate changes can be established readily by isothermal transformation studies. Isothermal transformation studies were conducted on these steels as follows: specimens were austeni-tized at 1600°F for 15 min, transferred to a lead bath operating at a constant subcritical or intercritical temperature, held for various lengths of time, and water quenched. The specimens were sectioned for metallographic examination to determine the amount and the type of transformation products present. In order to determine the effect of boron on the formation rate of ferrite, isothermal transformation tests were made on the 0.20 pct C steel in both the boron-treated and boron-free condition at an intercritical temperature of 1375°F where ferrite is the only decomposition product of this low carbon austenite. The results of these tests are shown in Fig. 2, where the percentage of ferrite formed is plotted as a function of time at temperature. It is apparent that boron markedly decreased the transformation rate of austenite to ferrite at this temperature.

Jan 1, 1956

By R. A. Mosser

Production control of aluminum content of low carbon aluminum killed open hearth steels is being achieved by using an oxygen probe unit. Based on the free oxygen content of the bath after block, a preliminary chart for aluminum additions has been established. The aluminum aim is .040%. Controlled aluminum contents will result in eliminating coarse grain heats, high aluminum contents, and a reduction in aluminum costs. By reducing the frequency of high aluminum contents both cleaner and better rolling heats will be obtained. The savings in aluminum costs is an added benefit of lesser importance in comparison to the quality improvements gained by controlled aluminum contents. Although the main goal for the oxygen probe at Republic Steel has been to adapt it for production control of aluminum contents, future usage could be extensive. Immediate plans for using the probe are on degassed material, on fully blocked open hearth heats to improve manganese recoveries and ranges, and on machining grades to control oxygen content. Also by controlling the oxygen content of the steel to as close to equilibrium conditions as possible, cleaner steel will result.

Jan 1, 1972

JAN. 17-In what appears to be a general spirit of post-Christmas emotional malaise, most adult Americans have bidden farewell to the Forties and turned with no perceptible enthusiasm toward the Fifties. The dying decade had started amid a phoney war which verged on the romantic, stirred the pulse with excitement and seemed far away. A phoney peace dominates the new decade. The romance is no longer there. Nor is the excitement. Nor is the distance. While most of the world preferred to be chronologically correct and hold off for another year before celebrating the demise of the first half of the twentieth century, the United States with true competitive enterprise and a great whirl of words scurried into the second half a year early. This undue haste might perhaps have been dictated unconsciously by a yearning for the pattern of history to be repeated. For many centuries, ever since Roman times, the second half of most centuries tended to be far more tranquil than the first half. In Washington, Mr. Truman got on both sides of the mid-century line with all the aplomb of a good politician. He told Congress early in January that "the state of the Union continues to be good," as it nears "the midpoint of the twentieth century." Later he spoke of moving forward into the second half of the century. He promised an infinitely better life for everyone, whichever side of the mid-century line, and reaffirmed his prescription toward that end: assistance for small businesses; more houses for the middle-income groups; tougher anti-monopoly laws, retention of rent controls; development of natural resources; better insurance against the hazards of old age, idleness and unemployment; better medical care and education, civil rights legislation; new labor relations law and production payments to support farm incomes. All this was to be coupled with suggestions on how to balance the budget. The bloody and confusing 1940's had brought to most men's minds a fear of the future such as they had not known for centuries, and Mr. Truman's objective is to temper that fear. Only time will tell whether the terminal point of such a philosophy would or would not belie the old English proverb citing inability to both eat and have a cake. Brave words to the contrary, the national budget persisted in sliding off into the red. The smell of further inflation was equally persistent. And just to impart a little more zip to the trend, the American Federation of Labor announced its intention of seeking "substantial" and "large" wage increases this year. The AFL forewarns of a business slump after June and a 10¢ an hr wage in¬crease for each worker "will be enough to reverse the prospective downward trend and start a rise." Thus it goes-"the way to halt a drop in demand for labor is to raise the price of labor." Elsewhere in the harassed world, beleagured individualists in New York achieved a local triumph of sorts for one of the freedoms denied by the Soviet and Nazi systems-the right of escape, some escape at least, from the servitude to decibels. Grand Central Station weakened perceptibly at Christmas on its 5-min commercials and bore down heavily on "Hark, The Herald Angels Sing," and on New Year's Day capitulated entirely by abandoning the broadcasting of canned music and slugs of advertising slogans. In Europe, M. Bidault's Assembly majority fell away and newspaper accounts of the incredible monstrosities of political trials beyond the iron curtain were supplanted by headlines marking the birth of Princess Yasmin. The latter was surrounded by Byzantine splendor but otherwise showed no apparent deviation from the accepted norm. In Western Germany, Dr. Adenauer began to speak up more boldly, and the whole fabric of Allied policy towards the defeated enemy further dossolved under the impact of rivalry with the Russians. In the Far East both the Americans and British seem somewhat embarrassed by Chiang Kai-shek's refusal to lie down. Dual thinking regarding the "squalid and useless struggle in the China seas" is such that newspapers give sympathetic accounts to an American ship running supplies to the Communists at Shanghai while calling for help for the recognized Chinese government in Formosa. And with Britain recognizing Communist China they may well have to team up with Russia against the United States to kick the Chinese representative off the UNO Security Council, the Far Eastern Commission and the Allied Council in Tokyo. Far Eastern policy has never been a bipartisan matter and as General Chiang retreated to his final redoubts in Formosa and Hainan, a number of Republicans pecked away at Administration lassitude. Senator Smith advocated the occupation of Formosa and Messrs. Hoover and Taft asked for use of the Navy. Mr. Acheson has stood firm, however, against military aid. None the less, a study will be made of the Generalissimo's chances. Mr. Truman has a private purse of $75 million for the Far East and some $94 million in frozen ECA funds. Mr. Truman will likely trade some of this money for support of new Marshall plan appropriations, always mindful, of course, of Mr. Acheson's plan to drive a wedge between the Chinese and Moscow, and his wish to avoid any revival of imperialist nightmares throughout the Orient. Mr. Acheson is very convinced that the victories of Communism in China will be short-lived and South Asia will not fall

Jan 2, 1950

Following the usual custom, three meetings are planned for the year. The Mid-Continent meeting will be held at Oklahoma City, Okla., Oct. 7 and 8, and the California meeting is planned for Los Angeles, probably also early in October. A program along the usual lines is under way for the annual New York meeting. Discussion and planning of the year's activity started in March. An effort is under way to secure papers dealing with some overlapping phases of engineering, petroleum geology, geophysics, law, economics, refining, etc. The main reason for attempting a program along these lines is the belief that unusually interesting technical papers can be obtained. The degree of specialization in the technical and related fields has permitted but few individuals to develop a sufficiently comprehensive viewpoint. Also, at times the developments in a particular field are capable of giving great stimulus toward much needed solutions of difficult problems in others fields of activity. With the coming of the period of restriction of production to market demand, many changes have occurred in policy and technique of petroleum production. Some changes have been advances, others have been of retrograde nature. It seems doubtful whether the adjustment to the condition of excess producing capacity has been complete or sound in some major respects. Many changes are in progress and others need to be initiated. The industry has excessive producing capacity so far as immediate market demand is concerned, but reserves for several years hence are generally believed insufficient. Exploration and discovery should go forward but development should proceed with caution and under control. Property rights should be clarified and protected for the new condition— without excessive cost for drilling wells that serve no purpose except that of giving some protection to property rights at the cost of an increased price to the consumer. Under the more steady condition of assured supply for the immediate future, as compared to the hand-to-mouth condition of wide-open production, a greatly advanced technique of development and production is possible and is being developed. Great progress has been made, but much remains to be done. Along some important lines progress can be effected only by better understanding between the engineer and the geologist, the lawyer, the politician, the geophysicist, etc. There is need

Jan 1, 1937

By Theodore A. Blake

At the Chicago meeting of the Institute, May, 1884,I had the pleasure of announcing the introduction of a new machine for fine crushing, or The Blake multiple-jaw crusher, which, in combina tion with the ordinary Blake breaker, could be used in the reduc tion of ores or any hard and brittle substance to almost any degree of fineness. I am now able to give some practical results derived from its use on an extensive scale, on the gold ores of South Caro lina and the iron ores of Lake Champlain, together with some accurate and detailed statistics of the cost of crushing over one hundred thousand long tons of magnetic iron ores of the Chateaugay Ore and Iron Company at Lyon Mountain, Clinton County, N. Y., about thirty miles west of Plattsburgh. The construction of the multiple jaw-crusher, since the date of my first paper, is the same, except in the substitution of main swinging, instead of main sliding, or toggle jaw,—thus doing away with the upward thrust on the tension rods and the wear incident thereunto. (See Fig. 1.) It has also been found, in case of the fine crusher, that is, in machines of not over 4 inch width of opening, that the use of several small machines with a series of jaw openings, say 15 inches by 4 inch, is better than one large machine with a series of openings 24 by 4 inch, or 36 inches by 4 inch, as at first constructed. Many details of the method of holding in jaw-plates, etc., have been perfected. Without giving any details with respect to the different mills built upon the Blake 'system, let me state that, although it has proved possible to carry any hard and brittle material with crushers alone to a fineness such that all particles will pass a 30-mesh wire screen, still the economical limit of such crushing will be found somewhere between 14 and 20. If it is necessary to carry all the material to a fineness greater than this, the system must be supple

Jan 1, 1888

By C. W. Sherman, John Chipman

IN the mathematical statement of the law of mass action, the activity of each substance consumed or produced in a reaction is used to obtain a numerical constant which is characteristic of the equilibrium of that reaction at the given temperature. The activity in many cases is equal to, or proportional to, the concentration. If this is the case, any units denoting concentrations, such as weight percentage or mol fraction, may be substituted in the equilibrium expression. It is even permissible to use mixed units provided only that each unit is that used in defining the activity of the corresponding substance. The indiscriminate use of concentration units in writing equilibrium constants sometimes leads to very erroneous results. On the other hand, what appear to be contradictory results from similar investigations often might be resolved if the activity is the quantity that is used to determine the equilibrium constant for the reaction in question. De-sulphurization serves as an important illustration. Sulphur in lron and Steel The control of the sulphur content of the finished product is one of the oldest and broadest problems in the metallurgy of iron and steel. In general, this control must be exercised through the action of a slag, and for this reason experimental studies of the distribution of sulphur between slag and metal have assumed considerable importance. Under slags of the type found in the basic open-hearth furnace the ratio (% S)/[% S] does not in general exceed about 8. Under blast-furnace conditions, however, de-sulphurization ratios of 50 to 100 are readily obtained, and under laboratory conditions using similar slags, the ratio may be as high as 400. The fact that blast-furnace metal is much more readily desulphurized than is molten steel rests upon two distinct phenomena. The first of these is connected with the slag reaction. In the open-hearth furnace, the equilibrium in the following reaction places a definite limit on the sulphur content of the slag: S + 0-- = 0 + S- - where the symbols underlined indicate elements dissolved in the liquid metal, while slag constituents are represented as ions. The high oxygen content of the open-hearth bath prevents this reaction from proceeding far enough to effect good desul-phurization. In the blast-furnace process, however, the oxygen activity is limited by the presence of carbon in the metal and in the coke bed and the controlling reaction becomes: S_+O- + C_=S- + CO(gas) [2] The second phenomenon which contributes to the easier desulphurization of blast-furnace metal is the effect of high concentrations of other elements. These elements, notably carbon, silicon, and phosphorus, increase the thermodynamic activity of sulphur several fold. As a result of this increase, the escaping tendency of sulphur from the metal phase is increased and its removal facilitated. Previous Studies It becomes, therefore, a matter of importance to determine the effects of various elements upon the activity of sulphur in the melt. The experimental approach to this problem has been made through the equilibrium between sulphur in the melt and gaseous atmospheres containing hydrogen and hydrogen sulphide. The reaction and its equilibrium constant are written as follows: S + H2(gas) =H2S(gas);K1 = -- [3] Pn2 • as where the symbol a, represents the activity of the sulphur in solution in the metal. The understanding of the chemical behavior of sulphur in steel and pig iron rests on a firm knowledge of the binary system Fe-S. A number of studies of the equilibrium have given closely agreeing results from which the activity and free energy of the dissolved sulphur may be found. The recent paper by Sherman, Elvander, and Chipman1 includes a discussion and quantitative comparison of the results of several of the significant researchesr-" on dilute solutions of sulphur in iron. The results of this study indicate that the relationship between the ratio Ph,s/p+ and the percentage of sulphur in solution is not a linear one. This

Jan 1, 1953