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By Thomas Chance

ALL gravity methods for the separation of ore from gangue, or of slate and other refuse from coal, are based upon differences in the falling velocities, in some fluid medium such as air or water, of the materials to be separated. As all materials falling in a vacuum have the same velocity, independent of the size, shape, weight or specific gravity of their individual particles, it would be more accurate to describe the operation of these methods as depending upon the. retardation of falling velocities effected by the resistance of a fluid medium, this retardation being greater for small or light particles than for large or heavy particles. This generalization is true also of those appliances utilizing centrifugal force to replace or to supplement the action of gravity. The separation of materials of different specific gravities by means of a fluid having a specific gravity greater than that of the lighter particles and less than that of the heavier particles has not been applied commercially, or on a large scale, to the separation of ores or to the washing of coal, the method being limited to laboratory experimental work or to laboratory determinations for the purpose of checking up the work of jigs, classifiers, and other types of concentrating appliances. A solution of zinc chloride has thus come into general use inn the laboratory to separate coal, bony coal and slate, both to check up the work of coal-washing plants and for the purpose of making tests preliminary to the designing of coal-washing plants. The use of a heavy solution of some chemical in water has often been proposed for making such separations, especially in connection with the washing or preparation of coal. Practically insuperable difficulties, however, have prevented the commercial development of any such process, the difficulties being both physical and financial. The cost of the chemical used to make high-gravity solutions is usually prohibitive, and the freeing of the coal from all traces of the chemical is found to be practically impossible. Such solutions inevitably penetrate the individual lumps and particles of coal, transfusing into the pores and saturating the joint-planes, and very large quantities of wash water

Jan 2, 1918

By Wilson T. Lundy

The history of the production of sulfur from salt domes in Louisiana and Texas originated with the operations of the Union Sulphur CO. at Sulphur, La., followed by the Freeport Sulphur Co. at Bryanmound, Tex. Including the present development of Grande Ecaille by the Free-port Sulphur Co., which constitutes the tenth dome to be equipped for the production of sulfur in the Gulf Coast, less than 10 per cent of all the known domes have proved to contain sulfur in commercial quantities. The Grande Ecaille salt dome is in the tidal marsh of the Mississippi River delta in Plaquemines Parish, Louisiana. It is 10 miles southwest of the right descending bank of the river approximately 45 miles below the city of New Orleans and is within 4 miles of the shore line of the Gulf of Mexico. Terrain Characteristic of the delta region, the terrain consists of a low, flat, uninhabited area of marsh land intersected by many shallow lakes and bayous. With the exception of salt grasses, the region is devoid of vegetation and presents, in all directions, an unobstructed path to the vagaries of the winds. The general character of this area can be best visualized from the mechanism of its formation.' Offshore bars formed enclosing long narrow lagoons between the bar and the inner shore line, the lagoons communicating with the sea by means of tidal inlets. The water in the lagoons, being comparatively quiet, favored the deposition of fine debris composed of sand carried into the lagoons by action of the waves, tides and river-borne sediments from the land surface. As this material accumulated the bottoms of the lagoons were built up and eventually salt grasses obtained a foothold. The successions of growth and decay of these grasses formed a brown fibrous mat varying in depth from a few inches to several feet. This mat of vegetation virtually floats on an ooze that is several feet thick and is composed of alluvial sediments and very fine sand, and the whole is underlain by an unctuous clay. The decayed vegetation from the upper layer when dried has a peaty appearance.

Jan 1, 1934

By F. B. Foley

With the possible exception of high-speed tool steel, the service demanded of rock-drill steel is probably more precarious than that of any other tool steel. Unaided by the helpful influence of alloys and dependent solely on the efficiency of the heat treatment applied for its ability to stand up under the abuse to which it is necessarily subjected, rock-drill steel is worthy of intensive study. For its heat treatment the smith has his fire, an oil fire perhaps, and a quenching bath; he judges the temperature by his eye. There are shops where excellent drills are produced by this method, but there are more where the product varies between very good and very bad. Pyrometers with specially designed equipment are used in but few cases. But the responsibility for rock-drill failures does not rest entirely on the smith. Little has been published concerning the efficiency of drill steel, though the Canadian Mining Journal1 published the breakage record of a large number of hollow drill steels. This record indicates that most of the breaks occur during the early life of the steel and that as a given batch of steel is used, its percentage of breakage decreases. This fact, the article points out, is at variance with the much-talked-of theory concerning failure from crystallization and fatigue. It seems to point to the fact that the greater part of drill-steel failure from breakage is traceable to faulty manufacture, resulting in defects in the bore of the hollow steel from inclusions of slag or oxides, etc. As this defective material meets with early failure, it is weeded out. In addition, some breakage may be caused by a lack of proper condition with respect to heat treatment of the steel as furnished by the manufacturer. In the article mentioned, the breakage of 1/14-in (3.17 cm.) hollow steel is given as 4.62 per cent. for the early period of use, with a decrease to 3.35 per cent. and 2.67 per cent. with time in use. For 1-in. (2.5 cm.) hexagonal hollow steel, the figures for breakage are 0.18 per cent. and 0.06 per cent.; attention is called to the great decrease in breakage by the use of smaller diameter drills. The figures are given as so many drills sharpened, but there is no way of determining the percentage of

Jan 1, 1922

By Avnulf Muan, Egil Aukrust

Activity-composition curves jor cobalt oxide and manganese oxide in solid solutions with spinel-type structure have been determined by studying the equilibrium between the spinel phase and a coexisting solid-solution phase in the tewzperature range 1100" to 1400"C. Within limits of experimental error, the system displays the behavior of a regular solution. The excess integral free energy of mixing is represented by the equation . The standard free energy of formation of cobalt manganite, CoMn,O,, from the oxide components COO mzd Mn2OS at 1200°C is calculated to be -8.6 kcal. AMONG the technologically and theoretically most important oxide phases are those which crystallize with the same structure type as the mineral MgO . A120,. Although the name spinel originally was used only for this mineral, the term is generally used today to designate the whole group of oxide phases with this same structure type. It is in this wider meaning that the term is being used in the present paper. The previous literature on spinels is very extensive. There are two aspects of spinels which have attracted particular attention: the structure, including the nature and distribution of the cations present, and the physical properties (electric, magnetic). The status of knowledge in these fields has been well-summarized in recent review articles.1'2 By contrast, thermodynamic properties of spinels are virtually unknown. Delineation of the activity-composition curve over the whole composition range of a solid-solution series with spinel-type structure is the objective of the present work. The system at elevated temperatures (>1000"C) constitutes such a series. The activity-composition curves for this system can be calculated from a study of the equilibrium between the above spinel solid solution and a solid solution (Co,Mn)O with sodium chloride-type structure. Data for the latter solid solution have become available recently.3 The system, in contact with metallic CO at 1200°C, obeys Raoult's law. The determination of the activity-composition curve for the spinel phase is based on the following relations. Consider the reduction-oxidation equilibrium for cobalt ions according to the equation: Because it is impossible in practice to measure single activities of electrically charged constituents, we will treat the equilibria in terms of electrically neutral components. Eq. [I] can then formally be written as follows: where and the activities of cobalt oxide in the (Co,Mn)O and the spinel solid-solution phases, respectively, K is a constant at constant temperature, and Pa is the oxygen pressure of the gas phase. The numerical value of K can be determined from a determination of the oxygen pressure P& for the equilibrium coexistence of Cos04 and COO in the binary system Co-0. Under these circumstances be set equal to 1, and hence K = [Po Eq. [3] can therefore be written

Jan 1, 1964

By Harry M. Mikami, A. Gene Sidler

Chemistry of the evolution of materials in contact with copper converter tuyeres is delineated by means of analyses of periodic punch rod samples taken during a converter cycle. Lining samples from known peripheral and end locations from three converters were investigated chemically and petrographically. One set of eight specimens representative of all lining parts was removed for study before completion of the campaign. Purely surface removal by slag action is minor. Slag filling of interconnecting cracks extending to the hot face results in a "stoping'' action which shapes the hot face contour and is a significant factor. Major wear mechanism is believed to be copper metal slabbbing caused by metal first penetrating joins and invading fractures or impregnating brick structure laterally from the joints. Importance of lining design and joint fit are emphasized. New laboratory tests are indicated. In the copper converter, molten matte, which is essentially a solution of iron and copper sulfides, is blown with air to produce blister copper. During the first stage of the process the FeS component is oxidized to SOz and FeO, the latter combining with a siliceous flux to form a predominantly ferrous silicate slag. Successive increments of matte and flux are charged, blown, and skimmed of slag until sufficient CuzS ("white metal") has accumulated. This white metal is then blown to copper metal in the final or blister-forming stage by the oxidation of sulfur to SOz and the reduction of combined copper to metal. The reactions of both stages are exothermic so provide the required heat. Temperature is controlled by cold scrap copper, flue dusts, smelter reverts, and so forth. Considerable vari- ation in practices occur depending on the type of converter, grades of the matte and flu, and other factors. Lathe and Hodnett's' survey of world converter practices gives much information on these variations and their effects on the refractories. Principles of converting chemistry are presented by Newton and wilson,' Ruddle,' and schuhmann. Most copper converting occurs within the temperature range 2100" to 2370°F although individual smelters report1 ranges from as low as 1700" to 2240°F to a high of 2200" to 2400°F. Temperature intervals reported from beginning to end of blow varied from 45" to 540°F. Average temperature range was 2030" to 2260°F and the average interval 250°F During the matte-blowing stage varying amounts of magnetite (FeO.Fe,O,) are formed in the slag as suspended crystals and also the liquid portion of the slag will contain, in addition to ferrous silicate, some Fe20s which adds to the potential magnetite formation if the temperature falls. This is a component of the so-called "dissolved magnetite" often referred to in the literature. Although the slag may contain minor amounts of CaO, A1209, MgO, and alkalies, the principal components are Fe0-Fez03-SiO,. The phase equilibria relationships of this system have been elucidated by Muan~ and Schuhmann, et a1.' These data and estimates of converting atmospheres by schuhmann4 are useful tools in studying slag behavior. It would appear that in many cases reported magnetite contents of slags are apparently higher than actually is present at operating temperature. This is probably because much of it is formed during slag solidification. The quaternary systems which have Mg-0,1,0,' and addition to iron oxides and silica are also of interest in considering the reactions of the slags with basic refractories. The formation of magnetite has an important interrelationship throughout the pyrometallurgy of copper (Mossman,' Gronningsater and Drummond," Ruddle,' Elwood and Henderson") but its presence in the converter particularly relates to operating efficiency and lining life in certain instances. Archi-

Jan 1, 1963

By D. B. Robinson, J. Lukacs

A knowledge of the equilibrium water content of hydrocarbon systems under pressure is important to the natural gas industry. The information available on the solubility of water in hydrocarbon, hydrogen sulfide, and carbon dioxide systems is reviewed in this paper and the influence of the more important variables such as temperature, pressure and molecular structure on solubility in liquids and gases is discussed. A suitable cbromatographic technique has been developed for determining low concentrations of water. Tailing of the water peaks has been elim inated by adding water to the carrier gas stream The method is applicable for both gas or liquid samples and is effective in the presence of hydrogen sulfide. The experimental study of water solubility in methane-hydrogen sulfide systems at a temperature of 16oF has shown that the presence of hydrogen sulfide causes only a modest increase in water content at pressures up to 1,400 psia. Theoretical considerations and data on pure hydrogen sulfide and carbon dioxide suggest that the effect of both these compounds will be greater at higher pressures and in the liquid phase. INTRODUCTION Before transporting or processing natural gases and gas condensates, it is usually necessary to dry them using suitable dehydration equipment. The design and operation of this equipment requires a knowledge of the amount of water present in the fluid at the reservoir and operating conditions. This is influenced by temperature, pressure and composition, particular1y when certain non-hydrocarbon components are present. Field experience indicates that hydrogen sulfide and carbon dioxide, for example, alter the usual water solubility relationships appreciably. However, an extensive search of the literature does not reveal any quantitative data on such systems. For sweet natural gases, generalized empirical correlations such as the one proposed by Katz, et al,6 can be used to predict water solubility with confidence at most temperatures and pressures of interest. However, existing theoretical relationships do not permit a calculation of the deviation from these curves when polar substances like hydrogen sulfide are present in the system. Thus one must resort to an experimental approach to obtain the necessary information. The fact that laboratory experimental methods frequently involve the use of mercury which reacts with hydrogen sulfide in the presence of water, and that hydrogen sulfide interferes with many chemical reactions specific for water has contributed to the difficulty of studying water solubility in systems containing hydrogen sulfide. In this investigation the water content of a limited member of methane-hydrogen sulfide mixtures was determined using a special technique with gas chromatography. REVIEW OF PUBLISHED DATA Experimentally determined water solubility data have been reported for methane, 14 ethane, 15 propane, 9 n-butane, 16 1-butene, 11 hydrogen sulfide 18 and carbon dioxide. 19 These studies report the effect of pressure, temperature and molecular structure on water solubility in single component gases and liquids. Fig. 1 compares experimentally determined water solubilities in several hydrocarbons, carbon dioxide and hydrogen sulfide at l00F as taken from this

By D. W. Philips

THE problem of strata control has of necessity been prominent in mining, and accounts of individual experience and research abound in the literature of most mining countries. Organized research began in Britain by the formation of a committee, upon the recommendation of the Safety in Mines Research Board in 1923, to investigate methods of reducing accidents from falls of roof in coal mines. This committee examined current practice in supporting underground workings in the principal coal fields, and its findings have been published in the Board's publications. Toward the end of these investigations it was suggested by the Chief Inspector of Mines that committees of the several mining institutes be formed to examine the problem in their respective districts. The formation of these committees marked a new phase in research on strata control. The work, though being done in the separate coal fields, followed a scheme outlined by the Chief Mining Engineer of the Research Board, and was coordi¬nated by his office. FACTORS INVOLVED The subject is being considered in Britain from two aspects: I. To provide, by supports, means to prevent falls of fractured ground. 2. To develop methods whereby the strata can be maintained in the least broken condition and thus make falls less likely. The first aspect is the one that will most likely lead to immediate results from the accident standpoint. It depends largely upon the assimilation of already acquired knowledge regarding the proper¬ties of supports and their correct applica¬tion. The second aspect is perhaps more fundamental, and involves also the proper¬ties of the strata and their behavior under the influence of the forces induced by mining. The problem involves many natural factors that cannot be controlled, such as depth, inclination and thickness of seam and nature of the rocks. Other factors, which may be considered to a certain extent controllable, cannot be varied readily and with sufficient fre¬quency to facilitate easy investigation; some of these are: rate of advance of the working face, length of face, direction of the face with regard to cleat and inclination, system and arrangements of rock packing behind longwall faces. In any given case the very many factors present have a mutual influence upon the effects produced in the mine. For example, a study of the effects of rate of advance cannot be done without considering the effects of other factors such as nature of strata, direction of face and quality and arrangement of supports. Conversely, the length and direction of a working face

Jan 1, 1946

By W. D. Potter, E. T. Peters

Single-crystal films of boron have been prepared by thermal reduction of purified BCl3 with subsequent deposition of boron onto oriented silicon substrates. The structural properties of films prepared under various experimental conditions have been determined by light microscopy and "grazing-" angle electron-diffraction analysis. An orientation relationship is proposed for silicon and a-rhombo-heclral boron which can be described as: (111)Si (112)B; [110]Si [110]B ElEMENTAL boron is known to have a high energy gap* and consequently has potential value as a high- *Energy gaps of 1.35 to 1.55 ev1-3 and 2.0 ev4 are reported for ß-rhombohedra1 and a-rhombohedra1 boron, respectively. temperature semiconductor.5 Exploitation of this property, however, has been hampered by the unavailability of pure, single-crystal boron. Two recent symposia6,7 have treated the subjects of purification, crystallization, crystal structure, and properties of boron and provide a foundation for further investigation in these areas. The structure, lattice constants, and observed ranges of stability for four reported polymorphs of boron8°12 are listed in Table I. The rhombohedral structures are generally accepted as true polymorphs whereas the tetragonal structures are believed to be transient. Most currently available single crystals of boron are grown by Czochralski and floating-zone methods. Unfortunately, these crystals generally contain numerous defects and are highly strained as a result of the polymorphic transformations and thermal contractions which accompany cooling. Recently, Armington, Potter, and Tanner13 have reported the formation of single-crystal films of boron on silicon single-crystal substrates through thermal reduction of BC13 by hydrogen. Boron E. T. PETERS, Junior Member AIME, is Senior Scientist, ManLabs, Inc., Cambridge, Mass., and W. D. POTTER is Research Chemist, Air Force Cambridge Research Loboratories, L. G. Hanscom Field, Bedford, Mass. formed at temperatures near 1000°C was identified as the a-rhombohedra1 form, consistent with expectation. The present paper describes a continuation of this work with specific reference to characterization of the structural features of the deposited boron films. The ultimate goal of this program is to produce large-area single-crystal films of a-rhombohedra1 boron to be used for electrical and optical studies by other workers. PREPARATION OF BORON FILMS The experimental procedure of preparing thin films is similar to that described by Theuerer14 for the epitaxial growth of silicon by thermal reduction of SiC14 and has already been described as applied to the preparation of boron thin films.13 Briefly, a mixture of BCl3 vapor and dry hydrogen is passed over a heated silicon substrate. Thermal reduction of the BC13 allows deposition of boron on the substrate. The substrates were {111}-oriented, single-crystal silicon. Square specimens 0.63 cm on an edge by 0.1 to 3.0 mm thickness were prepared by

Jan 1, 1965

By C. A. Heiland

A. INTRODUCTION (C. A. HEILAND) I. PRINCIPLES OF TEMPERATURE COMPENSATION IN MAGNETIC INSTRUMENTS The principle underlying the majority of magnetic intensity variom-eters is a comparison of the force to be measured with another force of known magnitude. The known force may be (a) of a magnetic nature, such as magnetic fields produced by magnets or coils, or (b) of a mechan-ical nature, such as (1) the elastic forces of wires, or (2) the force of gravity, such as employed in bifilar magnetometers and magnetic balances. In instruments of such type, usually a magnetic system is employed, free to move about either a horizontal or vertical axis, on some sort of a suspension. If the earth's magnetic field alone were present, such a system would adjust itself into the direction of the field or that of its components. Owing to the simultaneous action of the comparison force, however, the magnetic needle assumes a position that differs from the direction of the magnetic force; for all such instruments, the angle of deflection a is given by tan a = F/X, where F is the known and X the unknown earth magnetic force component. In other words, the magnetic system merely serves as an "indicator" for the position of balance of the two forces. Considering the matter from this point of view, it is not immediately obvious why the temperature of such a magnetic system should modify the results. In magnetic instruments, we may distinguish two different effects of temperature: (1) a magnetic effect and (2) a mechanical effect. The first is due to the fact that the magnetic moment of a magnet drops with an increase in temperature. This drop is characterized by the temperature coefficient of the magnetic moment µ (see equation 1). The second effect is due to the change in the .torsion of suspension wires with temperature or to the expansion of lever arms of masses acting on magnetic balances.

Jan 1, 1932

By Y. C. Liu, R. H. Richman

Deformation and recrystallization textures of the a solid solutions of Cu-P, Cu-As, and Cu-Sb alloys are examined as a function of composition. It is found that the deformation texture of copper is unckanged up to a composition of 0.43, 0.41, and 0.24 at. pct of phosphorus, arsenic, and antimony, respectzvely, and then the transition to the 70 : 30 brass type of deformation texture proceeds linearly as the logarithm of the solute content. Recrystallization textures consist of strong, new components that do not all bear the usual<111> rotational relation to the deformation components. The dependence of the deformation texture transitions and the recrystallization orientations upon composition and solute-element type is discussed. A systematic evolution of individual recrystallization components in the annealing texture of copper was portrayed as a function of germanium or tin content in a previous study.&apos; Similar patterns of tex-tural change have been observed with copper-zinc alloys,2 and in less detailed studies of other systems.3,4 In fact, most of the literature dealing with preferred orientations in copper alloys indicates that the influence of solute elements upon textures in copper is of one general type. As the alloy content of copper is increased, the deformation texture changes from the copper type to the 70:30 brass type, and the annealing texture undergoes a comparable change from the (001) [ loo] orientation of unalloyed copper to the {113} <211> type of 70:30 brass, with the notable exception of copper alloyed with Periodic Subgroup V-B elements.4-8 In almost every case it is possible to describe the reorientations after annealing as 30 to 40 deg rotations about <1ll> poles of the deformation components. Since there is apparently not much difference in the final textures of the copper binary systems already investigated, only a limited variety of preferred orientations has served as the basis for current theories of the origin of annealing textures. In order to test the validity of the proposed theories, and the possibility that the <111> rotations are not unique, it would be most desirable to study the reorientation relationships of additional, and heretofore unanalyzed, recrystallization components if such components exist. Examination of the literature reveals a good deal of uncertainty concerning preferred orientations in copper alloyed with elements in Subgroup V-B of the Periodic Table. Phosphorus is known to inhibit the cube texture in copper when present in amounts as low as 0.01 wt pct,8 but the recrystallized matrix that occurs instead of the cube orientation was reported as either random or weakly textured, with orientations not observed in Cu-Zn, Cu-Ge, or Cu-Sn alloys.4-9 A Cu-0.75 at. pct As alloy apparently contained, along with the (001)[100] and (113) <211> type of recrystallization components, {110} <112> and (110) <001> components, whereas an almost random distribution of orientations was found in alloys of higher arsenic content.4 A {110} <001> component also appeared in rolledand annealed Cu-Sb alloys, but otherwise the recrystallization textures of Cu-Sb alloys seem to con-

Jan 1, 1962

By Richard A. Conkling

A shale layer, buried beneath two or three thousand feet of strata, in some instances, will upon folding become thicker in the synelines and thinner on top of the anticlines. This can be accounted for, in part, by the stretching on the crests of the fold and the compressing in the troughs; but this will by no means account for all of it, as is shown in the example herein set forth. It is my firm belief that the rest of the thickness is due to flow. What causes the movement, however, does not concern us here, SO long as there is movement, for this article purposes to show its effect upon the producing area of different sands. It is the author&apos;s hope, in this way, to drop a hint or two that may be valuable to the oil geologist, in making estimates of future productions and values of oil properties. An example will be given from property in the famous Gushing Pool in northeastern Oklahoma, where the author has had occasion to make a detailed study before recommending some property to his company, and has then been able to watch the results of this work. The author never mapped the surface structure in this pool, as this had been done by Frank Buttram when he was with the Oklahoma Geological Survey. We are using, therefore, a section of his map in this article for our surface contours. The main east dip comes farther east than this section shows. From the 10-ft. contours in Fig. 1, it will be seen that the surface folding is very slight, but in the contour map of the Bartlesville sand (Fig. 2), which was the greatest producing sand, we see much more complex folding. It seems that the folding becomes greater with the depth. Folding may have started in Middle Pennsylvanian times and continued through the Upper Pennsylvanian which is found at the surface. This may, or may not, have been the cause of the increase of folding with depth. However, the fact that mostly concerns us is the interval of shale between the Bartlesville sand and the Tucker sand. The Tucker is the next productive sand below the Bartlesville. Not enough wells have been drilled to the Tucker sand to make a contour map of it, but

Jan 1, 1917

By S. M. Purdy

Under certain conditions of hot rolling and air cooling from the hot-rolling temperature, bars of a high carbon (0.40 pct C) chrome-nickel austen-itic alloy were found to show magnetism even though no ferrite or martensite could be detected by microscopic or X-yay methods. The appearance of magnetism in such alloys may come from chromium impoverishment of the austenite grains near the precipitated carbide particles. SPORADICALLY, hot-rolled bars of Silchrome 10, an exhaust valve steel, have been found to be magnetic. Because of the analysis of the alloy—0.40 pct C, 18 pct Cr, 8 pct Ni, 3 pct Si —magnetism is unexpected. Preliminary investigation showed neither martensite nor ferrite to be present; only austenite and Cr23C6. Since a literature search was fruitless, a brief study was made of the appearance of magnetism in this alloy. The only basic difference between the two heats is the nitrogen content. Permeability was measured using a Severn magnetic gauge. This instrument consists of a magnet mounted on a counterbalanced arm. A set of calibrated plugs is placed in contact with one pole of the magnet. The specimen is placed close to the other pole of the magnet. If the specimen pulls the magnet away from the plug, it has a permeability greater than that marked on the plug. This technique is swift and reproducible. Previous experience has shown that the permeabilities obtained corresponded to those obtained on a permeater with a field strength of 100 oe. Specimens from both heats were annealed at temperatures between 1700 and 2300°F. One set of specimens was water cooled and another furnace cooled. All the water-quenched specimens were non-magnetic; the furnace cooled ones were magnetic as shown in Table I with no difference being observed between the two heats. Microstructural examination of the specimens showed the expected increase in carbon solubility with increasing temperature. Carbide solution was complete at 2200°F. The specimens heated to 1900°F or below showed some carbide precipitation from the hot-rolled structure. A furnace cooled specimen from a given temperature showed less carbide out of solution than the water-quenched specimen from the next temperature below; e.g., the specimen furnace cooled from 2100°F showed less carbide out of solution than the water-quenched specimen from 2000" F. These studies indicated that the appearance of magnetism was not related to the quantity of carbon in or out of solution and it was related to precipitation at temperatures below 1700" F. A set of samples annealed and water-quenched from 2100° F was aged for 4 hr at temperatures between 1000" and 1600°F; all were non-magnetic. A second set of samples, similarly annealed, was aged 1 to 24 hr at 1200°F with the results shown in Table II. None of the latter set of specimens showed magnetism until they had been aged about 8 hr. Magnetism was quite strong after aging 24 hr. X-ray diffraction studies on several of the magnetic specimens showed that the austenite had a lattice parameter of 3.58A and that the carbide was Cr23C6. Several of these samples were electrolytically digested in 10 pct HCl in ethanol, with a current density of 0.1 amp per sq cm. None of the particles in the residue were magnetic. Accidentally, one cell was run at 1 amp per sq cm; e.g., magnetic particles were found in this residue. After careful separation, the magnetic particles were mounted on a quartz fiber and their diffraction pattern determined using a 5.73-in. Debye-Sherrer camera with CrK radiation. These particles showed a fcc structure with a lattice parameter of 3.57A. Prolonged exposure, up to 16 hr, produced no other lines on the film. The following facts seemed to be established at this time: 1) Austenite was the magnetic phase. 2) Neither ferrite nor martensite could be detected. 3) Magnetization could be produced by aging at 1200°F. One explanation of these data is that the carbide precipitation impoverishes the region immediately around the carbide particle of carbon and chromium and increases the proportion of nickel. All of these serve to increase the Curie temperature of the region around the carbide particle. If the composition change is enough, the Curie temperature will rise above room temperature. If the volume of the affected region is great enough, the magnetism will become detectable. At low aging temperatures, composition changes are great enough but the overall volume of impoverishment is quite small

Jan 1, 1962

By E. W. Steele

In the copper-casting department of a modern electrolytic copper refinery there are two kinds of casting furnaces: the anode, for casting crude copper into anodes for electrolysis; the refined-copper, for casting the cathodes resulting from electrolysis into market shapes, such as ingots, wire bars, and cakes. Both furnaces are reverberatories of practically the same general design and are operated intermittently, putting through a charge normally in 24 hr. The treatment of the copper in the two furnaces is similar, in that oxidation followed by skimming and reduction (poling) is carried on in both; but in the refined-copper furnace, the work must be done with greater care and it is of extreme importance that not the slightest trace of impurity be introduced into the copper. The furnaces usually hold from 150 to 300 tons of molten copper, which constitutes the daily charge. Except in the case of furnaces in the Lake district, where the concentrates from native-copper ores are charged through the roof, the furnaces are charged through the side doors by charging machines similar to those used in open-hearth steel practice. In 1916, at the Perth Amboy plant, of the American Smelting & Refining Co., located at Maurer, N. J., a study was made of the possibility of firing the copper refinery furnaces with pulverized coal instead of by hand. The proposed method possessed obvious advantages over hand firing and coal was a much cheaper fuel than oil at that time. However, there were several objections to its use, the principal ones being the possibility of increasing the sulfur content of the refined copper and the additional slag that might be produced from the ash. The increase of the sulfur content of the refined copper was the more serious, as more than 0.002 per cent. sulfur is objectionable. Any increase of the slag would be expensive as the copper in this slag would have to pass again through the entire smelting and refining process. It was thought that certain modifications in operations and furnace conditions, which will be described later, would overcome these objections SO the proposition was discussed with a manufacturer of coal-pulverizing equipment. He was uncertain concerning the use of pulverized coal

Jan 1, 1925

By Sidney Powers, Alfred C. Lane

This paper aims to present the results of an investigation concerning gravitative differentiation in lava flows, based on a quantitative microscopic and chemical study of a Triassic basalt from Nova Scotia, and confirmed by data secured from a study of certain Keweenawan ophites. At Cape d&apos;Or, Nova Scotia, near the head of the Bay of Bundy, marine erosion has exposed a series of Triassic basalt flows in which copper has been sought for a number of years. Studies of the thickest flow of the series with regard to volumetric composition, specific gravity, and grain have been made by the junior author, and measurements by students at Tufts College, together with confirmatory observations of the same nature on this and other flows by the senior writer, and chemical analyses made by the Division of Chemistry, Mines Branch, Ottawa,&apos; all show differentiation in lava flows comparable to that in intrusive bodies. The work was made possible by the availability of the drill-cores, the property of Tufts College, and emphasizes the desirability of the study of drill-cores from other localities. Measurements of the specific gravities of certain Keweenawan lava flows of Michigan by the senior author, from material collected in 1915, will be given as a comparison to those of the Cape d&apos;Or flow. It has been found that the specific gravity of drill-cores, or volume per cubic foot, can be readily obtained by measuring their dimensions. This can be done to an accuracy of within 1 per cent. in pieces of core over 100 mm. in length by using a micrometer gage for the diameter, and taking the average of six measurements of the diameter; and the average of four measurements of the length made with a finely graduated ruler. Then, after weighing them, the weight in grams per cubic centimeter, or what is practically the same thing, ounces per cubic foot, is obtained. System-

Jan 1, 1916

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 Theo W. Robinson

The evolution of the modern blast-furnace from the embryonic stages of comparatively few years ago, has been the work of wide praetiee and experiment. That much is still to be desired, the experience of every furnace-manager mill testify. Mr. Walsh&apos;s paper on "The Irregularities of the Blast-Furnace Process, and a Practical Way to Avoid Them" (Trans., xv., 419), proposes a new solution of the problem of interior lines, and one that has given rise to not a little speculation and controversy. The investigation described in this paper was undertaken to test experimentally the theory of Mr. Walsh as to maximum reducing capacity. Briefly explained, Mr. Walsh&apos;s views (outside of his claim for increased efficiency due to having the bosh wholly within the meltingzone) are, that a furnace of contracted stack and throat, on his lines. may equal in product one of considerably greater cubical capacity. The explanation offered for the theoretical greater capacity per cubic foot of his furnace is, that the increased tension of gases caused by passing through the small area mill promote transpiration, thus facilitating reduction and permitting more rapid driving. This alleged relation will appear from a hypothetical case in which a furnace, A, constructed on Mr. Walsh&apos;s lines, has but 1/x of the cubical contents of a furnace, B, of modern type; the two being equal in height. In order that A shall have the same capacity as B, both working normally with the same mixture and burden, and

Jan 1, 1889

By William E. Newman

The smelting of galena in the ore hearth has been practiced in many countries for several hundred years with varying success. In the United States, the water-jacketed American hearths and the Jumbb hearths have found some favor in the Missouri lead belt, where large quantities of non-argentiferous galena concentrates are produced. In form and method of operation the ore hearth has changed but little since its earliest conception. A detailed description of the furnace is lot needed here; it has been fully described in most works on the metallurgy of lead and in many technical papers. Since its field is restricted to non-argentiferous galena, containing over 68 per cent. of lead, its use is limited to a few districts; and, on account of certain disadvantages attending its operation, modern sintering and blast-furnace practice has nearly driven it out of the Missouri field. It is not generally known that the cost of producing pig lead is smaller by the hearth method than by sintering and blast-furnace smelting. Yet it is doubtful if any metallurgist knowing this to be true would recommend an American hearth installation—by reason of the disadvantages which will be briefly enumerated. The furnace has been limited to a length of from 4 to 5 ft., requiring for its operation two men working an 8-hr. shift as a maximum. The product per man is small; the work is hot and laborious; and the difficulty of completely removing the dust and fume has made it a notorious source of lead poisoning, Although suitable for operations on a small scale a large number of hearths would be required for a plant smelting 10,000 tons of 68 to 70 per cent. concentrates per month; and the number of semi-skilled laborers would be six times the number of hearths—a condition which is prohibitive. On account of the high percentage of dust and fume produced, a large flue and bag-house installation is required and, in the past, the handling and re-treatment of this dust and fume has -been a serious problem.

Jan 1, 1916

By Horace V. Winchell

The laws here referred to are those which define the status of the prospector for mineral deposits in the soil or beneath it, establish his methods of procedure, protect him in his possession while searching for the subterranean treasures, and give him assurance of title when all required conditions have been fulfilled and valuable minerals discovered. Regulations for the operation of mines and the safety and health of mine employees are likewise subjects of Federal and State legislation, but are not within the scope of the present program. Various features of our present laws will be discussed in detail by able students of the subject, and specific remedies will be proposed for the most glaring defects. It is my purpose to present in this paper a summary review of the reasons why revision is needed and demanded by the great majority of those in daily contact with the industry. Reason Number One The first objection to the continuance of the present law is that it was not planned by its framers and the Congress which passed it to apply to many of the kinds of mineral deposits, nor to the mining conditions, which are controlled by it to-day. In 1866, under the title, "An Act granting the right of way to ditch and canal owners over the public lands, and for other purposes," was surreptitiously smuggled into existence our first mining law (14 Stats. at Large, Chap. 262, p. 251). This law provided that "whenever any person or association of persons claim a vein or lode of quartz or other rock in place, bearing gold, silver, cinnabar or copper, having previously occupied and improved the same according to the local customs or rules of miners in the district where the same is situated," etc., a patent might be granted an certain conditions. This was evidently an Act intended to validate claims already initiated, and to accord Federal recognition to mining locations made in

Jan 1, 1915

By Colin Baker, G. C. Smith

Investigation of the initiation and propagation of ductile failure in OFHC copper was undertaken to determine the role of nonmetallic inclusions. The effect of inclusion initiated voids on the formation of the internal cavity and the final shear separation was studied by metallographic eranzination of strained test pieces. A strain anneal technique was used to enlarge the voids under uniaxial stress conditions to elinzinate triaxial stress effects. Measurements of void size us stress and strain were made to show the point at which void im&apos;tiation begins and becomes an important factor in the deformation process. The work of separation of copper-cuprous oxide was determined to attempt to correlate the breakdown of the matrix inclusion interface with void initiation and propagation. The zloid shape and position relative to the tensile axis suggested an interface breakdown mechanisnz of initiation. Evidence is presented that shows a basic similarity between the central cavity propagation and the 45-deg shear portions of the failure. DUCTILE fracture has been studied by a number of workers1-lo and attention drawn to the importance of hard second phase particles in the initiation of the failure. Holes formed at the matrix-particle interface can elongate by plastic deformation and then subsequently expand sideways to link up and produce a major crack. This is usually observed first in the center of the macroscopically necked region of a test-piece where the hydrostatic stresses are at a maximum. As the crack spreads sideways towards the free surface of the specimen, well defined shear zones develop from the crack tip and the final separation is along a direction at approximately 45 deg to the stress axis. This shear failure may also be associated with voids formed adjacent to second phase particles. In this way a cup and cone type fracture is produced. The stage at which separation takes place between particles and the surrounding matrix has not been clearly identified. In addition, although researchers have dealt with anisotropy of tensile behavior" as a result of material fabrication variables, not much is known about the microstructural features of aniso-tropic behavior. In the present work evidence on these points is presented in relation to the behavior of copper containing second phase particles of cuprous oxide. I. MATERIALS AND PROCEDURES EMPLOYED The material used was +-in. diam or 2-in. sq cold-drawn OFHC copper bar which contained 0.6 pct by volume of cuprous oxide inclusions. These ranged in COLIN BAKER, Junior Member AIME, formerly at -mnF of Metallurgy, University of Cambridge, Cambridge, England, is presently Research Scientist Reynolds Metals Co., Richrnand, Va. G. C. SMITH, Member AIME, is Senior Lecturer, Department of Metallurgy, University of Cambridge. Manuscript submitted June 20, 1967. IMD size from approximately 1 to 6 p in length and 1 to 4 p in width. The shape was generally slightly ovoid. Tensile tests were made on specimens having a gage length of 2.5 cm and diameter of 0.643 cm. Metallographic examination was carried out by sectioning deformed and fractured specimens; in addition fracture surfaces were examined optically and with a scanning electron microscope. Some measurements of the work of separation between copper and cuprous oxide were made, using a sessile drop technique which was a modification of that used by Kingery and umenick." The best metallographic results were obtained by using a vibratory polisher, which minimized smearing of the surface. 11. RESULTS A) Initial Experiments. Specimens from the +-in. diam rod were annealed for 2 hr at 650°C in uacuo, at which temperature complete recrystallization occurred without any change in the form of the inclusion. They were then fractured at temperatures from -190" to 600°C. Cup and cone fractures were obtained at all temperatures from -196" to 400°C. With increase in temperature there was, however, a continuous increase in the extent of the central transverse area and a corresponding decrease in the shear portion of the fracture. Above 400°C, the fractures became intergranular. Sections of specimens tested below 400°C revealed extensive small voids which were always associated with inclusions. However, the voids only reached dimensions greater than the inclusion size in the region of the macroscopic neck, where they were many times longer. Lateral expansion was found only near the fracture surface of the test pieces. As observed by Puttick, the voids were either (a) triangular holes initiated in the direction of the tensile axis and elon-

Jan 1, 1969

By J. M. Clark

For some years past, those interested in the development of the increasingly important mining industry of Canada, havc urged the adoptioi~ by the Dominion Parliament of a federal mining-law, which would have the force and stability of statutory enactment. At present, placer-mining in the Yukon Territory is governed by the Yukon Placer Mining Act. All other mining under federal jurisdiction is governed by Orders in Council and Ministerial Iiegulations. In the earlier stages of development, it is perhaps a matter of neces~ity that these important matters should be so dealt with; but it is now felt that the time has come when mining-rights in the extensive regions under federal control should be put on a permanent basis, and that any changes required from timc to time should be made only after full and open discu~sioii in Parliament. A short sketch will suffice to indicate how vast and varied the interests affected really are. When the Dominion of Canada mas constituted by the Inlperial Statute known as the British North America Act of 1867 (which into force by proclamation on July 1 of that year), it comprised only the present Provinces of Ontario, Quebec, Nora Scotia, and New Brunswick; but provision was made for the inclusion of Newfoundland, Prince Edward Island, British Columbia, Rupert&apos;s Land, and the North West Territories. Subsequently Rupert&apos;s Land and the North West Territories were acquired, the Crown Colonies of British Columbia and

Jan 1, 1912