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By Robert F. Brindisi

There are approximately thirty to forty operating mills in the United States which are currently producing uranium yellow cake. This figure includes a significant number of in situ and by-product operations however the conventional acid leach flowsheet depicted in Figure 1 is the most common process used by domes- tic yellow cake producers. Ground ore is leached with sulphuric acid and the solids are separated from the pregnant liquor and washed in a series of counter- current decantation thickeners. After clarification of the pregnant liquor, uranium is recovered from the solvent extraction/stripping circuit by the addition of ammonia with precipitation of ammonium diuranate, or simply yellow cake. The yellow cake precipitate is then thickened in a conventional thickener before re- porting to the dewatering/washing unit operation. De- watered solids subsequently report to thermal drying, and clarified liquor from the dewatering/washing step is recycled to the yellow cake thickener. The yellow cake dewatering/washing unit operation is generally accomplished using either a solid bowl centrifuge or a rotary vacuum drum filter. In most cases the underflow from the yellow cake thickener is pumped to the dewatering/washing unit operation at approximately fifteen to twenty percent solids. For the purpose of this discussion ammonium diuranate, the product of ammonia precipitation from a conventional acid-leach uranium mill flow sheet, as discussed earlier, will be considered. With only slight adjustment this discussion will be equally applicable to sodium diuranate or uranium perioxide precipitates and to either in situ or by-product operations where such precipitates are generated. Some of the domestic uranium mills which have selected solid bowl centrifuges instead of vacuum drum filters for the dewatering/washing unit operations are listed in Figure 2. Why have these uranium mills, as well as others not listed, chosen to use the solid bowl centrifuge for this particular application? It is simply a matter of performance, reliability and economics. In the remainder of this paper the performance, initial cost, installation cost, maintenance and power consumption of both the solid bowl centrifuge and the rotary vacuum drum filter will be com- pared. In order to provide a consistent basis for comparison the appropriate sized (centrifuge or filter) unit for the dewatering/washing of 400 to 500 pounds per hour of yellow cake solids will be considered. Such a flow will usually be generated by a typical 3,000 ton per day (acid-leach) uranium mill.

Jan 1, 1980

By Donald Barton

THIS paper outlines a time-saving graphical method of calculation for application to the interpretation of observations with the Eötvös torsion balance. Preliminary to the treatment of this short cut method which has been found practicable, the principal formu-las by which the student of interpretation can calculate the gradient and differential curvature produced by different types of bodies in different types of situa-tions are presented and discussed. It is necessary to split most geologic bodies into a series of simpler ones for which not too complicated formulas are avail-able. The gradient and differential curvature effects are calculated for each of the simple bodies and then summed to the total effect for the whole body. The calculations are considerable in number and, though more tedious than difficult, should be' entrusted to an experienced calculator. Considerable facility in qualitative interpretation can be acquired by the geophysicist from experience and from a thorough study of the types of gradient and differential curvature anomalies produced by the dif-ferent types of possible structural situations. How-ever, semi-quantitative calculations' of the probable structure bring out many relations that are not evident in a simple inspection of torsion balance results ; it throws out as impossible or improbable certain of the alternative structural possibilities that may seem equally probable under simple inspection of the results; it will determine more accurately the position of the crest of the structure; and reduce considerably the un-certainty in the interpretation and it is necessary to intelligent interpretations. The calculation of such cross-sections consists of a trial-and-error calculation of a body that will give gradient and differential curvature effects as closely as possible the same as those observed. From his knowledge of the gradient and differential curvature produced by different types of bodies, the geophysicist sketches a tentative cross-section of the structure as indicated-to him-by the observed results of the torsion balance survey, and the calculator then splits the struc-ture into blocks, and calculates the gradient and differ-ential curvature block by block. If, as rather usual, the calculated .gradient and differential curvature pro-files diverge considerably from, the respective observed ones, it is necessary to add and subtract blocks from the cross-section until a close agreement is obtained .between the calculated and observed profiles. The com-plete calculations have to be gone through for each block that is added or subtracted.

Jan 9, 1928

By William J. Gillich, Gerald L. Moss

PREVIOUS studies of the shock loading of randomly oriented polycrystalline aggregates have firmly established that, after rather short load duration, hydrostatic compression closely approximates the shocked state.' However, McQueen deduced from pressure measurements with good time resolution that, during shock loading, metals begin to undergo a stress relaxation at the yield stress. He suggested that the relaxation is due to plastic deformation accompanying the change from a one-dimensional compression to a three-dimensional, hydrostatic, compression.' Stress relaxation may occur faster as stress is increased above the yield stress, but the existence of unidirectionally compressed states for finite times suggests that the concept of a unidirectionally distorted lattice should furnish considerable insight into the mechanical behavior of materials subjected to shock loading. Here, a crystallographic analysis is presented for the hypothetical situation where atom motion may be considered as unidirectional which, as indicated above, is a useful extension of the macroscopic concept of shock loading to the microscopic domain. Only motion caused by the com-pressive forces is treated; i.e., lattice vibrations upon which this motion is superimposed, as discussed by Fitzgerald, are ignored.3 The purpose of the analysis to be presented is to develop a description for single crystals of the lattice rotations that occur for idealized uniaxial strain deformation. The usefulness of such an analysis in realistic deformation is to give a method of specification of those properties of an initially distorted lattice which would affect the subsequent deformation. Non-axial complications that arise experimentally, such as off-axis rarefaction waves, must be treated in proper context. Consider the material element shown in Fig. 1 and let the compression be uniform at all regions of the element. Then, any interior point of the element is displaced in proportion to its distance from the base of the element. Accordingly, if the top of a unit element is displaced by an amount, (-K), with respect to the base, a point P(X, Y) will be displaced by (-KY). Crystal planes are, therefore, rotated by the compression. Analysis of this rotation may be accomplished from the geometry shown in Fig. 1 where the line OP is the edge of the plane {hkl} and N is its normal. The orientation of the crystal plane with respect to the shock direction is specified by the angle, before deformation. After deformation the edge of plane {hkl}

Jan 1, 1969

By A. R. Jr. Amos

LOG washers have been used for many years in the washing of clay iron ores, phosphate rock and manganese ores, but not until the past 15 years have they been employed to any extent in the preparation of aggregate materials and fluxing stone. For a machine of such importance where tenacious clay or soft rock must be eliminated, there are few data generally available. The purpose of this paper is to set forth the results obtained from several operations, together with a few suggestions for planning a specific installation. Where the material to be washed out consists of loose surface soil, silt, or small amounts of quickly soluble clay, there is little competition with other forms of washers, because greater power and maintenance are required for the operation of log washers, but where the foreign matter is a stiff clay, such as occurs with high-calcium limestones and in marginal gravel deposits, the ability of other kinds of washers to eliminate com-pletely the hard clay balls is at least uncertain. Then the log washer comes into its own field, for with the breaking and churning action of the logs it will clean out the toughest clay. Even with material from the hydraulic dredge, if it contains tough clay, the log washer is desirable unless the gravel is subjected to a costly soaking and rehandling process. Recently there has been a considerable development in other types of machines to accomplish these results but it is not within the scope of this paper to make comparisons between competitive types, but to present the best obtainable data on log washers only. From the primitive design that gave it its name, a long log hewn from a tree, with paddles forged to shape from strap iron and attached by lag screws, the log washer has gradually been developed to the present all-steel type. As now manufactured, the log washer consists essentially of two built-up logs on which are mounted a series of paddles, carried by shafts fitted at the ends of the logs on bearings fastened outside the enclosing steel box, or trough, which is set at an angle of about 5° to 10° and into which the material is fed. Stuffing boxes at the places where the shafts pass through the box at the lower end are equipped with water-

Jan 1, 1936

By Albert Hoskinson

PROGRESS on the earth depends to a large extent upon the rapid inter-change of ideas and commodities between the various nations of the world. The smooth flow of commerce, by which these ideas and com-modities move, is accelerated by accurate and complete maps of the various land and water areas of the earth, The production of accurate maps depends upon a complete knowledge of the figure and dimensions of the object to be charted, therefore a knowledge of the shape of the earth is a prime necessity for accurate charting purposes. Gravity observa-tions were first undertaken to aid in determining the shape of the earth so that the geodetic surveys of its land and water areas might be more accurately connected to form an undistorted map. A large part of the earth's surface is water and it is therefore necessary to get gravity values at sea as well as on land before a complete and accurate figure of the earth can be determined. Dr. F. A. Vening Meinesz, of Holland, was the first scientist to perfect a pendulum instrument that would accurately measure gravity at sea. He had previously developed a multiple pendulum apparatus for measur-ing gravity upon swampy and unstable land areas in Holland and it was therefore quite natural that he should adapt the instrument to give accurate results upon a still more unstable support, the surface of the sea. His instrument as perfected gives satisfactory results when mounted in gimbals on any vessel where the roll and pitch are not more than about 5° and where the vibrations from rotating machinery and wave action are not large enough to cause the pendulums to shift on the knife-edges. This degree of stability can be obtained on surface craft only in protected waters or on very calm days. Therefore, Dr. Meinesz mounted his instrument in a. submarine so that he could submerge below the disturbed surface waters and get the desired stability in nearly any kind of weather by simply diving to greater depths. Most of the gravity-at-sea work has been done with a Meinesz instrument and a very large number of the observations have been made by Dr. Meinesz himself. He has occupied nearly 1000 sea stations and probably has traveled as many miles by

Jan 1, 1938

By J. R. Long, T. R. Graham, R. S. Dean

FOLLOWING the development of elec¬trolytic manganese production by the Bureau of Mines, an extensive program was planned to study the character of this high-purity product and its possible utilization in various alloy combinations. Previous work reported in the literature concerning alloys containing substantial amounts of manganese dealt largely with material prepared from relatively impure grades of the metal, and in many instances the impurities thus introduced did not permit true evaluation of manganese as an alloying element. One phase of the Bureau's program included a general review of the system and the establishment of the physical properties of copper-manganese-zinc alloys, using electrolytic manganese, and with particular emphasis directed to com¬positions within the alpha solid solution area. A number of reports of the work on alloys in this system, giving specific data concerning the equilibrium system and some of its alloys, have already been published. One study1 established the alpha solid solution area at various temperature levels and composition ranges up to 50 pct manganese. Other investigation reports presented the properties of selected alloys; namely, a 65 pct copper, 10 pct manganese, 25 pct zinc alloys' a sensibly white manganese brass composed of 70 pct copper, 20 pct manganese, 10 pct zinc,3 and a series of alloys with a constant copper content of 60 pct and 5 to 25 pct manganese, balance zinc.4 In these reports tensile properties as influenced by cold-working and subsequent annealing were given in detail. Additional data are now available on other alloys of the alpha region up to 50 pct manganese, and these, together with previously published information, are sufficiently complete to establish the relationship between properties and composition for this portion of the ternary system. The present report is a summary of the tensile properties of wrought alloys in the form of sheet and rod stock. The summary is necessarily limited to data for only one condition of cold-work and a single annealing temperature, since a complete exposition of all the data available would be too extensive for this presentation. Nevertheless, it is possible to make a reasonable approximation of the tensile properties in other conditions of cold-working and annealing by a correlation of the data previously presented on specific alloys and the data given here.

Jan 1, 1947

By M. B. Standing, D. L. Katz

Equilibrium data are reported on the composition and densities of coexisting vapor and liquid phases as a function of Pressure and temperature for four hydrocarbon systems prepared from crude oil and natural gas. The data were observed over a range of pressures from 1000 to 8220 Ib. per sq. in. and at temperatures ranging from 35' to 250°F. The compositions of the hydrocarbon systems were such that the critical temperatures of the mixtures were lower than the range of the investigation. Under these conditions, it is shown that the composition of the systems has a marked effect upon both the absolute value of the equilibrium constants and the change of the constants with pressure for the several components comprising the system. From weight-balance considerations, it has been possible to construct the partial phase diagram of a mixture of a 49.9" A.P.I. crude oil and natural gas having a gas-oil ratio of 3660 cu. ft. per barrel. Descriptions of the apparatus used, the analytical procedure, the material used, and the equilibrium measurements are included. A knowledge of the physical behavior of naturally occurring hydrocarbon mixtures is fundamental to the treatment of many problems in the production, transportation and rehing of petroleum. The recent discoveries of pools having formation pressures up to 7500 lb. per sq. in. and higher, and the development of full-scale equipment to operate at pressures of 5000 lb. per sq. in. or more have greatly increased the need for knowledge of the composition, temperature, pressure and density relationships of coexisting vapor and liquid hydrocarbon phases. The following paper presents the results of investigations upon 22 mixtures of natural gas and crude oil of known com~o~itio~ that had been brought to equilibrium under controlled conditions of temperature and pressure. Data are presented upon the densities and compositions of the coexisting vapor and liquid phases for four different systems containing hydrocarbon material having boiling points from minus 2 5S°F. to well over I000 F. The data were observed Over a pressure range from Iooo Ib. per Sq. in to 8220 lb. Per sq. in. and a temperature range from 35' to 2 50°F. The accepted method of computing the physical relationship between two coexisting phases of a hydrocarbon mixture is by use of the "equilibrium constant" K as proposed by Souders, Selheimer, and Brown. definition,

Jan 1, 1944

By M. B. Standing, D. L. Katz

Equilibrium data are reported on the composition and densities of coexisting vapor and liquid phases as a function of Pressure and temperature for four hydrocarbon systems prepared from crude oil and natural gas. The data were observed over a range of pressures from 1000 to 8220 Ib. per sq. in. and at temperatures ranging from 35' to 250°F. The compositions of the hydrocarbon systems were such that the critical temperatures of the mixtures were lower than the range of the investigation. Under these conditions, it is shown that the composition of the systems has a marked effect upon both the absolute value of the equilibrium constants and the change of the constants with pressure for the several components comprising the system. From weight-balance considerations, it has been possible to construct the partial phase diagram of a mixture of a 49.9" A.P.I. crude oil and natural gas having a gas-oil ratio of 3660 cu. ft. per barrel. Descriptions of the apparatus used, the analytical procedure, the material used, and the equilibrium measurements are included. A knowledge of the physical behavior of naturally occurring hydrocarbon mixtures is fundamental to the treatment of many problems in the production, transportation and rehing of petroleum. The recent discoveries of pools having formation pressures up to 7500 lb. per sq. in. and higher, and the development of full-scale equipment to operate at pressures of 5000 lb. per sq. in. or more have greatly increased the need for knowledge of the composition, temperature, pressure and density relationships of coexisting vapor and liquid hydrocarbon phases. The following paper presents the results of investigations upon 22 mixtures of natural gas and crude oil of known com~o~itio~ that had been brought to equilibrium under controlled conditions of temperature and pressure. Data are presented upon the densities and compositions of the coexisting vapor and liquid phases for four different systems containing hydrocarbon material having boiling points from minus 2 5S°F. to well over I000 F. The data were observed Over a pressure range from Iooo Ib. per Sq. in to 8220 lb. Per sq. in. and a temperature range from 35' to 2 50°F. The accepted method of computing the physical relationship between two coexisting phases of a hydrocarbon mixture is by use of the "equilibrium constant" K as proposed by Souders, Selheimer, and Brown. definition,

Jan 1, 1944

By A. R. Jr. Amos

LOG washers have been used for many years in the washing of clay iron ores, phosphate rock and manganese ores, but not until the past 15 years have they been employed to any extent in the preparation of aggregate materials and fluxing stone. For a machine of such importance where tenacious clay or soft rock must be eliminated, there are few data generally available. The purpose of this paper is to set forth the results obtained from several operations, together with a few suggestions for planning a specific installation. Where the material to be washed out consists of loose surface soil, silt, or small amounts of quickly soluble clay, there is little competition with other forms of washers, because greater power and maintenance are required for the operation of log washers, but where the foreign matter is a stiff clay, such as occurs with high-calcium limestones and in marginal gravel deposits, the ability of other kinds of washers to eliminate com-pletely the hard clay balls is at least uncertain. Then the log washer comes into its own field, for with the breaking and churning action of the logs it will clean out the toughest clay. Even with material from the hydraulic dredge, if it contains tough clay, the log washer is desirable unless the gravel is subjected to a costly soaking and rehandling process. Recently there has been a considerable development in other types of machines to accomplish these results but it is not within the scope of this paper to make comparisons between competitive types, but to present the best obtainable data on log washers only. From the primitive design that gave it its name, a long log hewn from a tree, with paddles forged to shape from strap iron and attached by lag screws, the log washer has gradually been developed to the present all-steel type. As now manufactured, the log washer consists essentially of two built-up logs on which are mounted a series of paddles, carried by shafts fitted at the ends of the logs on bearings fastened outside the enclosing steel box, or trough, which is set at an angle of about 5° to 10° and into which the material is fed. Stuffing boxes at the places where the shafts pass through the box at the lower end are equipped with water-

Jan 1, 1936

By G. Sachs, S. I. Liu

Introduction In a previous investigation on the effects of repeated strains of large magnitude on the aluminum alloy 24 ST, it was found that the reduction in ductility by straining in tension was partially restored by a subsequent compression.&apos; As illustrated by the dashed line in Fig I,$ the ductility (e~) retained after prestraining in tension by a certain amount (el) and measured in a subsequent tension test is represented by a straight line sloping down under 4s°. If a compression of the same magnitude as the first tension is inserted (€2 = — €1) between prestraining and final testing in tension, such a "balanced" tension-compression cycle yields a ductility considerably higher than that present after prestraining in tension only. The results of these tests can be correlated with those of an investigation on the effects of prestraining in compression.~ As also shown in Fig I, the ductility in subsequent tensile tests decreased with com- pression, at a rate considerably slower than that after prestraining in tension. The above discussed testing conditions can be considered as special cases of a general straining cycle, consisting of first, straining in tension by an amount el, subsequently straining in compression by an amount e2, and finally determining the retained &apos;ductility, e,, in a tensile test. Prestraining in tension is then represented by el > o and e2 = o. Prestraining in compression is given by e~ = o and e~ < o. Balanced cyclic straining is defined by the condition el > o and cz = — 61. In order to obtain further information on the effects of straining cycles consisting of tension and subsequent compression, further tests were made, varying both the tension strain, el, and the compression strain, e2, within extreme limits; el varied between 0.06 and 0.28 and e2 between — 0.008 and —0.h approximately. Apparently, such tests have not been previously performed. They revealed phenomena which have not been recognized to date, The results of the investigation are herewith reported, without attempting to correlate them with internal processes within the metal structure. However, in order to assist in an analysis of this type, the results have been represented in various manners. In addition, further test data on the effects of prestraining by compression were provided by using specimens of various contours (notched specimens) in the sub-

Jan 1, 1949

By Thos Gibson

THE object of taxation is the raising of a revenue. Unless a tax accomplishes this, it is a failure. The right to take for public purposes a part of the moneys obtained from the carrying on of private enterprises is an attribute possessed only by a lawful government, and may indeed he called the supreme attribute of government. In free, democratic communities this power must of necessity rest upon the consent of the governed. Power implies obligation, hence it is obviously the duty of a government, in framing a system of taxation, to provide one which, while effective in producing a revenue, is also just and impartial. It will be conceded that mines and mining property ought to bear a fair share of the public expenditure. The question is, upon what basis taxation should proceed. Two separate taxing principles are usually contended for: Taxation should be proportionate to the benefits received by the person or property taxed; taxation should be based on ability to pay. A third is sometimes added, taxation should have reference to the extent and value of the natural resources enjoyed. As applied to mining taxation, it is pointed out by those who support the first mentioned basis that, mines being usually situated in rocky and hence sparsely peopled regions, mining companies are frequently obliged to construct roads, railways, telegraph and telephone lines, schools, water and sewerage systems, and many other amenities and conveniences of civilization, the cost of which in regions better suited for agriculture and consequently more thickly populated, has either been defrayed locally, or can be spread over a sufficiently large taxable group of people to materially lighten the financial burden on the mine. The mining com¬pany, it is argued, having made these outlays, should receive credit for, them and be relieved of taxation to a corresponding extent. There may be some force in this contention, but the situation is capable of relief without attempting to place taxation upon so unworkable a basis as the value of benefits received. Who is to be the judge of these benefits, and how are they to be valued? The very existence of a mining company and its ability to carry on business in peace and security, depend on the prevalence of law and order, which is a result of good government. The state provides protection against violence, and courts of law for

Jan 4, 1919

By William R. Webster

I have continued the investigation of the Pottstown Iron Com pany&apos;s basic Bessemer keel plates on the line referred to in my paper of last October (Trans., xxi., 766)) and have added a study of the hardening effects of sulphur, which were not taken into account at that time. The results are so encouraging that I now give them in full. For some months we have graded all the steel at these works by the table given in my former paper, and checked the grading by the forging-tests as described in the paper of Mr. Joseph Hartshorne, read at the same meeting (Trans., xxi., 748). The steel thus graded was bloomed for the plate orders. Then one slab was rolled into a plate for the order, and a tension-test was made of this plate. By the result of this tension-test we were guided in rolling the balance of the heat. Out of several hundred heats graded in this manner, 95 per cent. met the requirements of the orders in every respect, and were accepted; but these results will no doubt be improved upon, when the influence of sulphur is also considered.. The hardening effect of sulphur seems to be about 500 pounds per each .01 per cent. of increase. In the table accompanying the pres ent paper, the ultimate strength with .06.5 per cent. sulphur agrees with the old table where sulphur was not considered; that is, for all steels with less than .065 per cent. sulphur we now get lower re sults, and for those with more sulphur, higher results. Making this allowance for sulphur, the assumed ultimate strength of a 3/8-inch plate of pure iron is reduced from 38,000 pounds per square inch to 34,750 pounds. With this as a basis, I have constructed my new table, giving each of the elements, carbon, phosphorus and manganese the same hardening effect as before, to wit : Carbon is credited with a constant effect of 800 pounds per each, 0.01 per cent. Phosphorus shows greater effect in high-carbon than in low-carbon steels. For 0.07 and 0.08 C, it has about the same effect as carbon, that is, 800 pounds for each .01 P. This increases to 1500 pounds per .01 P in 0.15 C steel, or nearly twice the effect of carbon. This

Jan 1, 1894

By G. Derge, Lo Ching Chang

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

By R. W. Harper, M. C. Fuerstenau, J. D. Miller

Data were obtained with hematite with octyl hydroxamate and oleate as collectors to determine the mechanism of collector adsorption and also to establish the roles that conditioning time and temperature assume in this system. The presence of hydroxy complexes of iron are apparently necessary for chemisorption of collector to occur, and it appears as if extended conditioning times and elevated temperature promote greater dissolution of the mineral and hence greater concentrations of hydroxy complexes. Data were also collected with two natural hematitic ores. With one ore that was ground to 70% - 15u, an addition of 0.4 lb per ton hydrox-amate resulted in a final concentrate recovery of 86% at a grade of 64% iron. Satisfactory concentrate grade could not be obtained with fatty acid under these conditions. The effect of conditioning time prior to the addition of collector was also examined with another ore. When the ore was conditioned for 3 min, 19% of the iron was recovered in the concentrate at a grade of 67% Fe. With a conditioning time of 7 min, 73% of the iron reported to the concentrate at a grade of 62% Fe. These products were obtained with an addition of 0.2 lb per ton hydroxamate. This ore also responded well to flotation with fatty acid. The use of potassium octyl hydroxamate as a collector for iron oxide has been the subject of an earlier study.1 From this initial study, it was suspected that hydrolysis of surface ferric iron was involved in collector adsorption. More recent work in other systems has shown that slight mineral dissolution, followed by hydrolysis of cations common to the mineral lattice, is apparently necessary, and that adsorption of these hydroxy com- plexes probably occurs prior to the adsorption of collector. In view of these facts, work has been continued on the hydroxamate-hematite and oleate-hematite systems to gain better insight into the mechanisms of collector adsorption on iron oxide. Microflotation experiments in conjunction with infrared analysis were used in this regard. In addition it was felt necessary to establish more clearly the responses that can be obtained from natural ores when hydroxamate is used as collector as compared to those obtained when fatty acid is used. Experimental Materials and Techniques Pure potassium oleate, potassium octyl hydroxamate, synthesized from hydroxylamine hydrochloride and methyl octanoate, and a distilled Tall Oil were employed as collectors. Conductivity water was used in the

Jan 1, 1971

By G. Derge

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

By D. J. McAdam, G. W. Geil, R. W. Mebs

As shown in previous papers by the authorsg-17t the resistance of a metal to fracture, like its resistance to plastic deformation, is a function of all three principal stresses. A technical cohesion limit is the technically determined resistance to fracture under a specific stress system. The technical cohesive strength thus comprises an infinite number of technical cohesion limits corresponding to the infinite number Of possible com-binations of the principal stresses. The technical cohesive strength, therefore, may be represented by a surface in a diagram with the three principal stresses as coordinates. As shown in previous papers,&apos;-&apos;&apos; the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,$ namely, the stress system, plastic deformation, temperature, and the strain rate. More- over, the influence of each of these factors on the technical cohesion limit has been shown to be qualitatively similar to the three of the same factor on the flow stress.9-18 Advance of knowledge about the conditions determining fracture of metals has been retarded by the reluctance of some investigators to abandon preconceived ideas about how metals &apos;&apos;should,, behave. The incorrect idea is still prevalent that the conditions determining resistance to fracture are very different from those determining the flow stress. Attempts are still being made to express resistance to fracture in terms of a single parameter, such as a limiting value of the greatest principal stress, the maximum shearing stress, or the volume stress (one-third the algebraic sum of the three principal stresses). In these attempts, a sharp distinction is sometimes made between a ductile or ,plasticdeformation, fracture,, and a "brittle frat-ture.H In making this distinction, however, the meaning attached to the term "brittle fracture" sometimes is not made clear. The term could mean fracture after very little plastic deformation or it could be used to designate the type of fracture. An ordinary fracture of a ductile metal at room temperature starts as a cleavage, generally transverse to the direction of the greatest principal stress, but eventually changes to a shearing fracture&apos; In some conditions, however, the metal fractures entirely by cleavage, with no evidence of plastic deformation during the fracture; the surface of such a fracture may have a

Jan 1, 1948

By R. W. Mebs, G. W. Geil, D. J. McAdam

As shown in previous papers by the authorsg-17t the resistance of a metal to fracture, like its resistance to plastic deformation, is a function of all three principal stresses. A technical cohesion limit is the technically determined resistance to fracture under a specific stress system. The technical cohesive strength thus comprises an infinite number of technical cohesion limits corresponding to the infinite number Of possible com-binations of the principal stresses. The technical cohesive strength, therefore, may be represented by a surface in a diagram with the three principal stresses as coordinates. As shown in previous papers,&apos;-&apos;&apos; the technical cohesive strength increases with plastic deformation, with decrease in temperature, and with increase in the strain rate. The technical cohesion limit, therefore, is affected by the same factors that affect the flow stress,$ namely, the stress system, plastic deformation, temperature, and the strain rate. More- over, the influence of each of these factors on the technical cohesion limit has been shown to be qualitatively similar to the three of the same factor on the flow stress.9-18 Advance of knowledge about the conditions determining fracture of metals has been retarded by the reluctance of some investigators to abandon preconceived ideas about how metals &apos;&apos;should,, behave. The incorrect idea is still prevalent that the conditions determining resistance to fracture are very different from those determining the flow stress. Attempts are still being made to express resistance to fracture in terms of a single parameter, such as a limiting value of the greatest principal stress, the maximum shearing stress, or the volume stress (one-third the algebraic sum of the three principal stresses). In these attempts, a sharp distinction is sometimes made between a ductile or ,plasticdeformation, fracture,, and a "brittle frat-ture.H In making this distinction, however, the meaning attached to the term "brittle fracture" sometimes is not made clear. The term could mean fracture after very little plastic deformation or it could be used to designate the type of fracture. An ordinary fracture of a ductile metal at room temperature starts as a cleavage, generally transverse to the direction of the greatest principal stress, but eventually changes to a shearing fracture&apos; In some conditions, however, the metal fractures entirely by cleavage, with no evidence of plastic deformation during the fracture; the surface of such a fracture may have a

Jan 1, 1948

By Gerald Edmunds

THE liquidus line on the phase diagram for temperature versus composition of a binary alloy system, representing the boundary between the homogeneous melt and the heterogeneous melt plus solid, besides showing the minimum casting temperature, is useful in determining eutectic compositions and the presence of phase changes such as peritectic transformations and intermetallic compound formation. The liquidus often is determined by the cooling curves of thermal analysis, but supercooling frequently occurs, so that the temperature values are low. An alternative method, the one employed here, consists of determining the com- position of samples of the melts from heterogeneous alloys that are at equilibrium. With meticulous attention to fundamentals, this method is capable of yielding values limited in precision only by the temperature control and measurement and analyses. APPARATUS By starting, on the one hand, with a supersaturated solution and allowing the excess solute to precipitate, and on the other hand with an undersaturated solution and allowing more of the solute to be dissolved, both processes being carried out at the same temperature, equilibrium may be said to have been approached from both directions; that is, from above and from below. If the analyses show the solutions to contain the same fraction of solute when equilibrium has been approached from above and from below, one is assured that equilibrium has been reached in both determinations. In order to carry out such determinations, it is necessary to have equipment for obtaining and maintaining the proper temperatures; for holding the melt, measuring its temperature, and stirring, sampling and analyzing it. The present work required temperatures from 420° to 900°C. The equipment consisted of: A furnace, which was a vertical alundum tube, 1 ¾ in. diameter inside and 18 in. long, wound with Nichrome resistance wire, surrounded by a 3-in. i.d. alundum tube wound for 5 in. of length near each end, for compensation of end losses. This muffle was contained in an iron shell with Transite end plates, the intervening space being packed with Sil-O-Cel. The outside dimensions of the furnace were 12 in. in diameter by 18 ½ in. in height. Heating current was supplied by three independent variable-voltage transformers (Variac), one connected to each end compensator winding and manually controlled, and one connected to the main winding through a series resistance of 5 ohms. This resistance was short-circuited for

Jan 1, 1944

By Jacques B. Wertz

Detailed structural studies in southeast Arizona have successively revealed (1) the local attitudes of individual fractures (with lateral and/or vertical displacements), (2) the patterns exhibited by groups of fractures, and (3) the trends and directions shown by fracture groups or zones on a regional scale. The results of the studies have been twofold: First, domes were locally determined from these fracture arrangements, even where other criteria failed; and, second, fundamental breaks brought out the breadth of the Texas lineament in southeast Arizona as well as major northwest- and northeast-trending fracture zones. Coincidence of one or several domes with the major intersections of fundamental breaks can be centers of important mineralization, as in the instances of Bisbee, Ajo and Morenci. THE OVER-ALL STRUCTURE OF ARIZONA A northwest-southeast trending anticlinorium has been suggested as the structural setting of Arizona. Starting in Triassic and culminating in late Cretaceous times, this deformation resulted from stresses of considerable magnitude with varying ratios of com pres sional and uplifting forces. However, the series of parallel flexures could just as well have been caused by isostatic movements involving dilation under tension with only incidental compression, as later emphasized by dike filling and block faulting (Fig. 1). The anticlinorial deformation, which is also suggested by the fact that the Pre-cambrian rocks to the southwest are all concealed by sediments, could be somewhat reminiscent of the conditions that affected the classical swarm of parallel dikes of wager.&apos; ANALYSlS OF DATA As a first step in this analysis, all structural information obtained on such features as fractures and their relative displacements, faults, dikes, anticlines, synclines, and Precambrian and Laramide-Tertiary intrusives were plotted on maps along with structural trends inferred from aerial photographic mosaics. Next, the faults in southwest Arizona were classified according to time of occurrence and relative importance. The fault assemblages were then examined as to geometric or spatial arrangement and correlated with the occurrences of domes and existing Finally, the conjunction of fracture intersections and domes was analyzed and compared with locations of known ore deposits. Differentiation of Faults According to Time and Relative Importance: The faults encountered were grouped as follows: (1) Basin and Range faults, latest in time; (2) secondary faults; (3) primary faults; and (4) lineaments, earliest in time by inference. BASIN AND RANGE FAULTS- Generally concealed by alluvium, the Basin and Range faults are normal

Jan 1, 1969

By Pei-Yung Huang, Carle R. Hayward

IN order to understand more fully the actual state of copper lost in copper reverberatory slags, a systematic study on the various reactions between certain metallurgically important copper compounds and synthetic copper reverberatory slags was undertaken by the authors in the Massachusetts Institute of Technology from 1942 to 1945.1 This paper, being only a part of the work completed, is published first because it furnishes the first experimental evidence of the formation of copper ferrite from reactions between cuprous oxide and copper reverberatory slags. CHOICE OF SLAG COMPOSITION The choice of the composition of the synthetic reverberatory slags to be used was much deliberated. Commercial copper reverberatory slags, neglecting minor constituents, average:2.3 45 to 47 pct FeO; 38 to 42 pct Si02; 5 to 6 pct CaO; 5 to 6 pct A1203. Since the ternary system CaO-FeO-SiO2 has been much more thoroughly studied4 and is much simpler than the quaternary system CaO-FeO-Si02-A1203, it was decided to use calcium oxide only instead of calcium oxide and alumina in the synthesis of the slags. Fortunately the composition of the average copper reverberatory slag with calcium oxide substituted for alumina lies in the region of the phase diagram clarified by the investigators. A survey of the phase diagram (Fig I) suggested two compositions: (I) the com¬position near the invariant point S, which is made up of 46 pct ferrous oxide, 37 pct silica and 17 pct calcium oxide; (2) the composition near the invariant point K with 45.5 pct ferrous oxide, 43 pct silica and 11.5 pct calcium oxide. Composition S has the advantage that the percentages of ferrous oxide and of silica almost exactly coincide with those of the average reverberatory slags, and that of the lowest melting point (1093° ± 3°C) in the whole ternary system. The calcium oxide content, however, obviously is high. Since we have already substituted calcium oxide for alumina, and since calcium oxide is more basic than alumina, the resulting slag is decidedly too basic. Composition K has a slightly higher melting point (1105° ± 3°C) and a higher silica content, but this is preferred because the slag is saturated with respect to tridymite and thus should not corrode siliceous refractories. Besides, it is less basic than composition S. The final slag composition, therefore, was chosen to

Jan 1, 1947