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By Carl F. Floe, Michael B. Bever

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By Gerald Edmunds

In a paper1 before this Institute in 1940, the writer reported that the surface orientation texture of zinc and cadmium differed from the texture existing within the casting, in that basal planes were parallel to the surface. He was unable to rationalize the , origin of this surface texture. It is conceivable that the surface orientation texture is influenced by the atomic force fields, which are different at the surface and within the body of metal. It was considered that a radical changc in the surface against which the metal is cast might alter the surface texture. In trial of this, zinc has been cast against a surface of molten lead, but the same result has been obtained—i.e., (001) parallel, ± 2oo, to the surface—as was obtained when it was cast against air, Transite or iron.' Into the bottom of an open cast-iron tray, 7 by 14 in. by 2 in. deep, preheated to about 275°C., about 1/4 in. of lead, then 1/2 in. of zinc was poured, and the whole was covered with an electric heater to enforce freezing from the bottom upward. After a lapse of time sufficient for the zinc but not the lead to solidify, the zinc slab was raised free of the molten lead. The bottom surface of the zinc casting was coated with a thin layer of lead. A specimen of the slab 136 in. square was metallographically polished to flatten it and remove the slight film of lead, and the orientation was determined by the method used before,' with the result stated above. Some determinations have also been made on other metals, as follows: Surface orientation determinations were made on the 3/8-in. diameter grip section of two 1/4-in. diameter aluminum-alloy die-cast tensile bars and on a 1/8 by 1/2-in. flat aluminum-alloy die-cast tensile bar. None of these three aluminum die castings exhibited any preferred orientation at the surface. A brass die casting (nominal composition: 60 Cu, 37.75 Zn, 1.00 Sn, 1.00 Pb, 0.10 Al, 0.15 Si) furnished by C. S. Smith was also examined. The surface showed a random orientation of alpha and beta. Summary A zinc casting solidified against a molten lead surface was found to have the same surface orientation texture, (001) parallel to the surface, as other zinc and cadmium castings. Aluminum and alpha-beta brass die castings were found to have random grain orientation textures at the surface. Acknowledgment The X-ray determinations were conducted by M. L. Fuller.

Jan 1, 1945

By Carl F. Floe, Michael B. Bever

THE possibility that carbon may be soluble in copper to a limited extent has been recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are frequently used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. REVIEW OF LITERATURE In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of o.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.92 58 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been in prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as o.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1945

By R. M. Brick

SEGREGATION can occur only in cast alloys that solidify over a range of temperatures with a difference in composition of liquid and solid phases within this range (ignoring monotectic systems and chemical reactions as in rimming. steels). Thus a pure binary eutectic alloy should show no segregation unless undercooling occurs for one of the solid constituents of the eutectic; e.g., chill-cast Al-12 per cent Si alloys. The phasial condition implicitly described above-solidification over a range of temperatures with a compositional difference between solid. and liquid-is found in nearly all solid solutions or combinations of solid solutions and eutectics. Metastable conditions of solidification of these types of alloys cause coring; i.e., a difference in composition between the center of a dendrite and its periphery. This composition gradient can be detected usually only by microscopic examination of etched structures; it is a "micro" effect. The gradient of more immediate industrial concern is that between the center of a cast section and the surface layers. This gross (macro) effect is usually determinable only by sampling of the casting at different points, with chemical analyses of each sample. If the compositional difference is of the same type as in coring, the first parts to freeze being enriched in higher-melting-point constituents, and vice versa, the effect is called normal segregation. When what is apparently the first part of the casting to solidify shows a higher concentration of low-melting-point constituents, the effect is called inverse segregation. These macro effects are quite separate from the micro effect, coring, yet the latter must be. described first because it is an essential part of the picture. CORING Solid Solution, Ni-Cu The nickel-copper phase diagram is reproduced in Fig. Ia, in which the solid lines represent the equilibrium liquidus 1, 3, 7 and solidus 2, 5, 8, and where the vertical 1, 4, 8 represents a 55 per cent Cu alloy. Upon moderately rapid solidification, the first dendritic axes of composition 2 (see Fig. 1b) start to form at a temperature somewhat under I. Solidification continues by growth of the dendritic nuclei, but at temperature 4 the increment solidifying is of composition 5. The rapidity of this crystal growth prevents diffusion of nickel and copper atoms from adjusting the composition of the entire dendrite at 5, which it would be under equilibrium conditions. The average composition of a specific dendrite, or the entire solid phase, at temperature 4 might be that indicated

Jan 1, 1944

By Walter Wood

The specifications for locomotive-cylinders, which are given in a separate paper at this meeting, have been prepared so that castings (upon the successful use of which so much depends) shall be made to conform to standards that will yield good results. After the essentials, which go with a sound and perfect cauting, the requirements to be borne in mind are those concerning the quality of the material. These have been determined from the actual practice of the largest users,—representatives of the American Locomotive Company, the Baldwin shops, and the Pennsylvania Railroad being upon the Committee. The results called for by the test-bar have been carefully checked by actual experiment upon metal that has given satisfactory service in cylinders.

Jan 1, 1905

By D. A. Stevenson, T. Alden, J. Wulff

A portion of the liquidus curve has been determined for the binary alloy systems Ni-Pb and Cr-Pb. The solubility of nickel is 0.53 atomic pet at 372° and 18.63 atomic pet at 1200°C. Chromium shows low solubility, 0.634 atomic pet at 1210°C. Molybdenum and tungsten were also studied and found insoluble in lead, less than 0.005 atomic pet at 1200°C. INCREASED use of liquid metals of low melting X point for heat transfer, coating, joining, and other purposes has renewed interest in the solubility of structural metals in these liquids. A study of Hansen1 and current literature indicates that few liquidus curves at the low melting end of the binary diagrams have been accurately delineated. This statement applies particularly to the binaries of lead. The present paper is limited to nickel, chromium, tungsten, and molybdenum in lead. In early studies2, 3 of the lead end of the Pb-Ni system, a monotectic at 1340°C was established. Tammann and Oelsen' determined the solid solubility of nickel in lead at 20°C to be 0.023 wt pet. Recently Pelzel5 determined the liquidus curve from the eutectic temperature of 327° up to 727°C using a segregation method. In the present paper this part of the curve has been checked and extended to 1244°C. The Pb-Cr system was first studied by Hindrichs.6 He pointed out the existence of a monotectic at 1470°C and indicated a tentative liquidus. Recent corrosion studies of Fe-Cr alloys in lead suggest that chromium is more soluble than iron in lead.7-8 The solubility of tungsten in lead according to Inouye8 is about 30 wt pet at 1200°C. Appreciable solubility of molybdenum in lead might therefore be expected. Experimental Various experimental techniques have been employed in the determination of solubility in liquid metals. For low solubility, thermal analysis is unsatisfactory. A segregation method was used by Pelzel3 in his study of the Pb-Ni system. In this procedure separation of liquid and solid is possible due to difference in density. In the technique of Kleppa10 a single piece of material is maintained in contact with the liquid metal in evacuated Vycor vials. After equilibration, solid and liquid are separated by tilting. Keck and Broder" measured the weight of a piece of the solid solute before and after immersion in a pure solvent bath; the weight loss was a measure of the solubility. All of the above procedures are time-consuming since they permit only one determination per run. Numerous samples for analysis may be taken from the melt in the method described by Gurinsky and CO-workers.10 The rate of extraction of samples is limited only by the time required for equilibration. In the present work, a modification of this method was employed. A 150-g charge of analytical reagent grade lead and the added metal* were contained in an Alun- dum crucible. It rested on firiely divided silica at the closed end of a 45 mm Vycor tube, 500 mm long. The top of the tube was provided with an inlet and

Jan 1, 1959

By Charles A. Stickels, Edward E. Hucke

The dihedral angle, formed by the intersection of three interfaces, is often determined by measuring a sample of apparent angles of intersection seen on a random plane of polish, then comparing the exerimental distribution of angles to the distribution calculated by Harker and Parker. Statistical tests show that the latter distribution does not satisfactorily describe the population from which samples are drawn. It is concluded that the major reason for this discrepancy is the presence of a range of dihedral angles in all specimens. When reasonable care is used experimentally, random measuring error is unimportant. It is shown that measurements made on dispersed second-phase inclusions are subject to a systematic error depending on inclusion size, which can be minimized by using adequate magnification. A dihedral angle, calculated from a sample of observed angles as though a unique dihedral angle were present, is termed an "effective dihedral angle". Experience has shown that "effective dihedral angles'' are reproducible quantities, useful for characterizing samples. Methods of determining an "effective dihedral angle", establishing its reliability, and making comparisons between samples are discussed. THE authors have recently reported measurements of the dihedral angle formed by liquid-lead inclusions lying in nickel grain boundaries.' Di- hedral angles were measured by the statistical method first employed by Harker and parker2 and used subsequently by many other workers.3"8 Since a relatively high degree of accuracy was necessary in the authors' experiments, the reliability of this method of dihedral-angle measurement was examined. Briefly, this method of measuring dihedral angles is usually performed as follows. A multiphase alloy is prepared, equilibrated under conditions which allow sufficient interface mobility to establish equilibrium, quenched to room temperature, then prepared for metallographic examination. A large number of observed angles, formed by the traces of grain boundaries and/or interphase boundaries on the plane of polish, are measured at high magnification. If all orientations of interfaces in the specimen are equally probable, Harker and parker2 showed that the population of observed angles is described by a distribution function containing a single parameter, the dihedral angle, 8. certain properties of the population, e.g., the mode or median, have been calculated from this distribution function in terms of the dihedral angle.3, 9 Thus, if the mode or median of a sample is identified with the corresponding property of the population, a unique value for the dihedral angle is determined. One defect in this procedure lies in identifying the properties of a sample of observed angles with the properties of the population from which they are drawn. If one were to proceed in a more rigorous fashion, it would be necessary to find a function of sample properties which is an estimator of the dihedral angle. Then by determining the distribution function for the estimator one could set limits on the value of the dihedral angle. The most apparent obstacle to this straightforward approach is the complexity of the distribution function assumed to describe the population. In analytical form, the distribution function may be written:2, 10

Jan 1, 1964

By M. R. Geer, H. F. Yancey

Coal washing assumed an important role in the mining industry of the Pacific Northwest long before washing practice became firmly established in the Appalachian field. A Scaife washer was operated in the state of Washington in 1887; and by 1927, the fist year for which complete statistics were compiled, nearly a third of the state's coal production was washed, in comparison with only about 5 pct for the country as a whole. Mechanical preparation was adopted in Alaska in 1922 in a plant constructed by the United States Navy at Chickaloon to provide bunker coal for naval forces operating in northern waters. Many of the coal beds mined in Washington and Alaska contained more impurities than those mined elsewhere, and this circumstance contributed to the early interest in mechanical cleaning. A much more important factor, however, was the inclination of the coal beds. With steeply pitching beds, hand sorting by the miner at the face is impossible; consequently, all material must be loaded and dealt with on the surface, just as is now proving the case with mechanical mining of flat beds. Thus "full-seam" mining afforded the same stimulus to the early development of coal washing in the Northwest that it is providing under mechanization in the rest of the country today. Objeet and Scope ' This report is intended to provide a general summary of the status of coal-washing practice in Washington, Oregon, and Alaska—an area in which some of the coals mined are more difficult to wash than those mined elsewhere in the country. Detailed flowsheets of plants, statistical data on production, and cost figures have been omitted, largely for the sake of brevity but also because such information is principally of only local interest. On the other hand, considerable washability data have been included because they are Washington At present Washington leads all other states in the percentage of its total production that is cleaned mechanically, 82.1 pct in comparison with the national average of 25.6 pct in 1945.' The washing problems encountered in this state are highly variable because the mountain-building forces that created the Cascade Range caused such intense folding and faulting of the beds in some fields that the rank of the coal was increased to anthracitic, while in other fields more distant from the mountains the beds were relatively undisturbed, and the rank of the coal ranges down through subbituminous to lignitic. The complicated and burdensome schedule of sizes prepared in most coal fields has never been required by the Washington market. With but few exceptions, lump is prepared on a round-hole screen of about 3 in. size, egg is about 3 to 1 5/8 or 1½ in., and nut is 1 5/8 or 1½ in. to either 1 or ¾ in. Some mines screen no finer than ¾ in. and market a slack coal of that top size, but generally the coal is screened at about ¼ in. to give a stoker coal of ¾ or 1 to ¼ in., and a ¼ in. to 0 "buckwheat." During recent years the market for lump coal has largely disappeared, and lump is crushed to supplement the pro-

Jan 1, 1950

By C. W. Dunham

DESIGN of the structures for the Morenci Reduction Works involved many interesting problems. Naturally, the chief purpose of these structures is to house and support the equipment and other things necessary for or incidental to the conduct of production. hence most of the features of the design were developed to suit these particular conditions; however, several are so generally applicable as to warrant description.

Jan 1, 1942

By E. P. Abrahamson

The effect of transition element binary solid solution additions upon the re crystallization temperature of nickel has been investigated. All additions raised the re crystallization temperature. Both the rate of change of re crystallization temperature with at. pet solute and the limit of initial linearity are found to correlate with the free atom ground state outer electron configuration of the solute element. A comparison of all of the correlations for the transition elements studied has yielded a set of empirical relations, which allows the prediction of the effect of dilute binary transition elements on the recrystallization temperature of other transition elements. The work of Abrahamson, et al.1-7 on dilute binary solution alloys indicated a correlation between the free atom ground state electron configuration of the solute and both the brittle-ductile transition and re-crystallization temperature. Further, it has been shown3,4 that the limit of initial linearity may also be correlated with the solute electron configuration. Since previous studies have dealt with bee and hexagonal base elements, this study is made to note what effect, if any, the fee base structure might have. Nickel also serves to give a solvent configuration which will allow the comparison of all of the transition element solvents. Olsen8 has studied the effect of some trace elements upon the recrystallization of nickel. He included only Ti, Zr, W, Mn, and Co of the transition elements. The differences in change of recrystallization temperature were attributed to the solute atom size and to the solubility of the solute in nickel. PROCEDURE All alloys were made using 99.9 + pet Ni with 0.003 C, 0.015 Fe, 0.007 0, and 0.0007 H. The solute elements were 99.9 + pet pure. According to the published binary phase diagrams9 and metallo-graphic examinations at X750, all solute elements were in solid solution. The alloys were arc melted and remelted four times in the form of cubic 200-g buttons under an argon atmosphere. They were then hot forged at 800oC to 0.750 in. diam, machined to 0.60 in., vacuum annealed for 1 hr at 700°c, swaged to 0.40 in. and annealed at 700oC for 1 hr in vacuum. The grain size was checked and found to be 77 * 20 grains per sq mm. The specimens were then swaged to 0.187 in., yielding 76 ± 1 pet cold work. All alloys were then chemically analyzed for the solute addition. The interstitial contents remained at the values of the starting material when checked on random alloy specimens. The swaged rod was cut into 8.25 in. lengths and heat treated in a gradient furnace for 1 hr. The gradient was maintained at 250" to 850°C over an eight inch length, recorded by twelve thermocouples. Control was ± 3oC, accomplished at the hot end. The recrystallization was determined metallo-graphically over the entire specimen. The criterion chosen was that point on the specimen showing the first recrystallized grain at a constant magnification, X200. Specimens were repeated, and the agreement was found to be generally ± 3oC.

Jan 1, 1962

By Harvey Cline, Donald P. Ferriss

THE violent outgassing of commercial tungsten and other refractory metals when melted in an electron beam zone refining apparatus1"3 is dealt with experimentally by one or both of two approaches. One is to provide a suitable emission current control1,2 the other is to purify the metal in the solid state before melting.4 The first of these is usually sufficient, but the authors chose also to investigate the source of the troublesome gases and to devise means of solid-state purification. Some further insights into the use of tungsten as a structural material at temperatures near its melting point were also revealed in the course of the work. One may speculate on the causes of gas formation in tungsten at high temperature by inferences from the literature and an examination of the impurities in commercial wire. Davenport5 observed microporosity in both tungsten and molybdenum filaments heated to several hundred degrees below their melting points. Studying the function of oxygen in molybdenum welds, Perry, Spacil, and wulff8 attributed similar porosity to the disproportionation of Moo2 to molybdenum metal and Moo3. Tungsten dioxide also disproportionates7 above 2000oC to yield WO3 vapor at considerable pressure. Commercial tungsten contains some 5 to 20 wt ppm O and a similar concentration of carbon depending on the details and precautions of processing. Therefore, evolution of CO is also a strong possibility as a source of gas at high temperatures. Furthermore, even for activities in the order of 0.01, it may be calculated that the pressure of CO at 3000°C would be over 4000 psi, which is in excess of the tensile strength of tungsten at this temperature.9,10 Powder metallurgy tungsten contains some 0.02 pet Fe and 0.002 to 0.005 pet of the elements Ni, Si, Al, Ca, Mn, Mg, and Mo; at temperatures over 2800°c, therefore, these elements will exhibit appreciable vapor pressure, though small compared to that of WO3 and CO. Some of these impurities may react to form high-pressure monoxides such as SiO and A10. Finally, dissolved and occluded nitrogen is an ever-present source of high-pressure gas. Commercial Type 218, General Electric filament wires, 0.025 in. diam, were heated by resistance in 10 -4 mm of Hg and in argon or hydrogen at pressures from 50 µ to atmospheric. For temperature determinations in vacuo, the Jones - Langmuir8 current-temperature relationship was employed. For gaseous atmospheres, the burn-out temperature was assumed to be the same as in vacuo so that a small, constant correction could be made for temperatures below burn-out conditions (i.e., local heating to failure). Several dozen experiments may be summarized by pointing out some structural observations. At 3050oC in 1 atm of A, porosity is very evident after 30 min, as shown in Fig. 1. For the section in Fig. 2, failure occurred 200°C below the melting point and many voids have grown in the grain bound-

Jan 1, 1962

By B. H. Kear

Clustering of slip bands in different systems has been observed in both ordered and disordered Cu3Au crystals compressed in the <110> orientation. Certain features of the slip band patterns are explained in terms of reactions between dislocations with Burgers vectors at 120 deg; in a few rare cases, the slip band evidence suggests that the Products of such reactions form diffuse tilt boundaries between the differently slipped regions of the crystal, similar to the known behavior of ionic crystals, but not nearly so well defined. WHEN crystals with orientations favorable for multiple slip undergo plastic deformation, slip may occur in different systems in localized regions, so that clusters of slip bands are developed. This phenomenon has been observed in fee1-4 metals and also in ionic crystals having the sodium chloride structure.5-8 In the ionic crystals, the boundaries formed between the differently slipped regions of the crystal assume characteristic orientations and are associated with macroscopic tilts that are plainly visible on the sides of the crystal. Recently, this interesting feature was explained in terms of the formation of diffuse low-angle boundaries as a result of interactions between families of glide dislocations in the different systems meeting in the boundaries.9 This paper describes an attempt to obtain similar evidence for boundary formation in an fee crystal. The alloy Cu3Au was chosen for the present study simply because this material is currently being used in a general study of differences in deformation behavior of the ordered and disordered phases of this alloy, which will be described elsewhere. EXPERIMENTAL PROCEDURE The two specially oriented compression specimens used in the present study were prepared from a melt-grown single crystal by careful cutting, grinding and polishing. The finished specimens were about 6 mm by 2 mm in cross section by 6 mm tall, with their ends parallel to (101) and sides parallel to (111) and (121); the broad faces of the specimens were made parallel to (711). Both specimens were annealed in an evacuated quartz tube at 850oC for several hours, slowly cooled to 500°c, and then quenched into water in order to obtain the disordered state for the alloy. One of the specimens was partially ordered (with S- 0.8) by reannealing at 350oC for 100 hr. After these annealing treatments, both of the specimens were electropolished. 10 Finally, the specimens were compressed in the [loll orientation and their stress-strain curves were recorded. The deformation was carried out in increments of a few percent strain. At each stage in the deformation the specimens were unloaded, removed from the compression jig, and examined optically for slip bands. Before reloading, the specimens were repolished, so that the observed slip band patterns were characteristic of a particular stage in the deformation. EXPERIMENTAL RESULTS Fig. 1 show!; the stress-strain curves for the ordered and disordered specimens and also indicates the stages 1, 2, and 3 where the deformation was interrupted for examination of slip bands. The curves show marked differences in flow stress and in work hardening rate in the two specimens, as observed by previous workers.11,12 Also, it was found, in agreemement with the observations of Taoka and Sakata,&apos;3 that the plastically deformed disordered alloy showed the characteristic coarse slip bands of alloys, whereas the ordered alloy exhibited a fine slip band structure similar to that of pure metals. Slip Band Observations. In what follows, the description of the slip band patterns, with accom-

Jan 1, 1962

By Paul J. Bennett, James E. Castle

The sillimanite family of minerals, including kyanite, sillimanite, and andalusite, are anhydrous aluminum silicates with the formula A12O3-SiO2. Dumortierite and topaz are also included in this group because they are closely allied in composition and thermal behavior. However, neither are mined commercially today. They are typical metamorphic minerals which are found in metamorphic rocks on every continent. Sillimanite minerals are prized chiefly for their refractoriness and are important components in a broad range of acid refractory products, especially in mortars and castables. World production of sillimanite minerals is currently about 400,000 tpy and has been increasing at the rate of 3 to 8% a year for many years (Anon., 1972). While these minerals have widespread occurrence, the consumption of sillimanite minerals is concentrated in the relatively few highly industrialized areas where refractories are manufactured, and which in turn are typically close to the major iron and steel producing regions of the world. Thus northern Europe,. England, the United States, and Japan are the principal consumers of refractories and sillimanite minerals. Of these countries only the US is a significant producer. Uses of Kyanite The following specifications are typical for the domestic kyanite industry: Raw Kyanite Concentrates Chemical Analysis 56% AI2O3 min 0.1% CaO max 42% SiO2 0.1% MgO max 1% Acid soluble 0.3% combined Fe2O3 alkali max 1.2% TiO2 max Available Sizes 35, 48, 100, 200, and 325 mesh The largest use for domestic kyanite, both raw and calcined, is in the manufacture of refractory mortars, cements, castables, and plastic ramming mixes. In these applications kyanite constitutes from 10 to 40% of the mixture, the balance being refractory clays and coarser grog materials. A certain proportion of raw kyanite is used to offset the shrinking of the clay binder, whereas the calcined kyanite is used in the coarser sizes for body. Certain high grade refractory shapes and kiln furniture are composed chiefly of graded sizes of calcined kyanite bonded with a little ball clay. In most applications, however, kyanite is used only to fortify the mix or as a minor ingredient. Some manufacturers of mullite brick use domestic calcined kyanite for the fine-grained portion of the brick, but seldom in quantities exceeding 10% by weight. Kyanite is used by ceramic manufacturers of wall tile and sanitary ware to offset shrinkage and cracking after firing. Indian kyanite has traditionally been used to make the coarse grog sizes needed for the manufacture of mullite brick, and for the grog portions of mortar, cement, and castable mixes. It has been largely replaced, however, by synthetic mullite, high fired flint, and diaspore clay or calcined bauxite for other applications. Indian kyanite has been available in lump as well as in granules and concentrates, as are sillimanite materials from India and South Africa. Andalusite is available as 8 mesh granules and as fines with chemical analyses not unlike those of domestic kyanites. From time to time and from place to place minor amounts of other aluminum silicate minerals such as dumortierite, topaz, and pyrophyllite have been made available at various prices and specifications, but have not been significant factors in the refractory industry. A mixture of kyanite and sillimanite of relatively fine grain-size and of low iron content was at one time offered to the molding sand industry by the Du Pont Co. as a byproduct from their deposits of heavy

Jan 1, 1983

By E. H. Crabtree, Neil S. Parker

The custom milling plant of the Eagle-Picher Mining and Smelting Co. is at Sahuarita, Arizona, approximately 20 miles south of Tucson. It is connected by a 2-mile railroad spur to the main line of the Southern Pacific Railroad between Tucson and Nogales. The capacity of the plant is 500 tons per day. The mill is conventional except perhaps in the rather wide variety of ores treated. These vary from straight copper ores, from which only one concentrate is produced, and lead-zinc or copper-zinc ores from which two concentrates are produced, to complex gold-silver-copper-lead-zinc ores, which require the simultaneous production of three or lour concentrates. Custom ores are received in lots varying in size from a few truckloads to several carloads. Similar ores, after crushing and sampling, may be commingled, or individual lots may be milled individually. The ores are first dumped either into one of two 200-ton railroad bins, or into one of the two 75-ton truck bins. From these bins the lot of ore is individually crushed in a 24 by 16-in. jaw crusher to 3-in. size, and then to ½-in. size in a 3-ft Symons shorthead crusher. After crushing to ½-in., the ore is conveyed to the automatic sampling plant. This consists of three Vezin samplers in series, each successively cutting out 10 pct, 10 pct and 5 pct of its feed. After No. I sampler, the material passes through a mixing barrel and is then crushed to -in. in a set of rolls before passing to No. 2 sampler. Between No. 2 and No. 3 samplers, the ore is again mixed in a mixing barrel. The final sample, consisting of one pound per ton of ore, is taken to the laboratory, where it is further crushed to 1/8-in. in a coffeemill, and then riffled down to the size required for grinding in a pulverizer. The capacity of the crushing and sampling plant is up to 100 tons per hour, depending upon the character of the ore. After sampling, the ore is stored in five ore-storage bins, consisting of four 200-ton bins and one 175-ton bin. Each of these bins is discharged by means of belt feeders and conveyor to the ball mills, so that ores may be composited for milling in any required ratio, or milled separately by themselves. Fine grinding is done in one 6 by 4-ft Allis-Chalmers ball mill and one 8-ft by 36-in. Hardinge mill. These two mills both discharge to one 54-in. Akins Simplex High weir classifier. The classifier sands can be returned to either or both mills, so that flexibility in grinding for different ores is easily obtained. Flotation equipment consists of four 66-in. Fagergren machines for copper-lead roughing and six similar machines for zinc roughing. Lead-copper bulk concentrate is cleaned and recleaned in eight No. 18-S Denver machines, and zinc concentrate is cleaned in three 66-in. Fager-grens. Copper-lead differential separation

Jan 1, 1949

By E. N. Cameron, H. M. Bannerman

During the years 1942-1934, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailcd studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country&apos;s needs in normal times? for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larra-bee, A. H. McNair, J. J. Page, V. E. Shai-nin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. Analysis oF Warrtime Operations In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 45 to 35 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the tram sition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1948

By H. M. Bannerman, E. N. Cameron

During the years 1942-1934, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailcd studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country&apos;s needs in normal times? for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larra-bee, A. H. McNair, J. J. Page, V. E. Shai-nin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. Analysis oF Warrtime Operations In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 45 to 35 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the tram sition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1948

By H. M. Bannerman, E. N. Cameron

INTRODUCTION DURING the years 1942-1944, about 125 New England deposits were mined for sheet and punch mica, and many others were briefly prospected. During this period the Geological Survey, United States Department of the Interior, carried on detailed studies of the deposits and the pegmatite bodies that contain them. The primary purpose of the studies was to provide geological information that would contribute toward efficient mine development and operation. The studies were aimed directly at practical production problems. Detailed maps showing the structure of the deposits were prepared, and geological findings were closely correlated with data on specific yields and costs of mining and processing. The result is information that permits a reasonably accurate appraisal of the mica deposits of New England and the mining industry that they support. At a time when the future of the industry is in doubt, it seems desirable to submit this appraisal for consideration. Domestic mica deposits supply only a small fraction of the country&apos;s needs in normal times, for only the richest domestic deposits can compete with the low-cost mines of India and Brazil. However, the possibility that this country may be cut off from its supplies in time of war gives domestic deposits an importance much greater than their peacetime production would imply. New England supplied about 22 per cent of domestic output in 1943 and 1944, the peak years of wartime production. Its actual contribution to the war effort was greater, for the proportion of sheet mica of high quality in the New England product is higher than the average for domestic mica. The data analyzed below were collected for the Geological Survey by D. M. Larrabee, A. H. McNair, J. J. Page, V. E. Shainin, G. W. Stewart, and the co-authors of this paper. The cooperation of officials of Colonial Mica Corporation and of mine operators and owners in furnishing information is gratefully acknowledged. D. M. Larrabee, A. H. McNair, and V. E. Shainin have made various suggestions based on critical reading of the manuscript. ANALYSIS OF WARTIME OPERATIONS In considering the data presented in this report, it must be remembered that the scale of mica operations is very small compared with that of many other mining industries. The typical New England mica mine of 1943 and 1944 was worked by a crew of five or six men. Equipment was varied but on the whole extremely simple. The first stage of operation at a deposit was normally opencut mining. Drilling was done mostly with jackhammers powered by portable compressors driven by gasoline engines. Muck was shoveled by hand into buckets with a capacity of 1/3 to 2/3 ton and commonly hoisted by derrick to a dump adjacent to the cut. As operations were carried to greater depth, and the transition to underground mining was made, these methods were modified to a degree depending largely on the attitude of the deposit mined. At steeply dipping deposits,

Jan 1, 1946

By E. C. Tveter, L. A. Roe

The authors present a general outline of the theory and development of heavy-liquid application to mineral processing. Patent literature and processes are reviewed with special emphasis on liquid recovery systems which have been employed or proposed. Advantages and disadvantages of the process are discussed together with the recent developments which have revived interest in this old concentration method. The most important single factor in this resurgence of interest is concluded to be the narrowing gulf between chemical engineering and mineral dressing which has opened the field for new concepts of mineral plant design. A partial summary of patents on heavy liquid separations is included. In spite of the fact that heavy-liquid separation with organic liquids has been used in the laboratory for over 50 years, this process has never graduated to large scale commercial use for any extended period. However, a variation of this process, the sink-float or heavy-media separation process has found wide acceptance and is used to separate minerals from diamonds to gravel. Materials used to increase the specific gravity of the pulps used as heavy media include sand, clay, barite, magnetite, galena, hematite, atomized lead and ferrosilicon. Because of the greater ease of recovery, the magnetic materials, magnetite and ferrosilicon, are the preferred media today. In the U. S. alone, heavy-media iron ore plants with a capacity of over 10 million tons of concentrate per year are in existence. Heavy-media separation involving use of solid, inorganic particles suspended in water rapidly found a wide range of commercial use with the introduction of magnetic media. The minerals engineer is experienced in working with suspensions and quickly learned to develop and control such media at a cost compatible to the type of separation desired. The natural superiority of a heavy liquid with uniform chemical and physical properties has never been questioned since its first use in laboratory mineral separatory procedures. It offers the only method for gravity separation of fine particles of relatively close specific gravity. The most important early attempt to make heavy liquid separations commercial were made by the DuPont Co. which began experimental work on Virginia limonite in 1904. The appended "Partial Summary of Patents" compiled by W.L. O&apos;Connell of The Dow Chemical Co. demonstrates the quantity and sequence of this work. Both inorganic and organic parting liquids were investigated and numerous patents were issued on the use and recovery of these liquids. The work culminated in the heavy liquid plant of the Weston Coal Co. at Shenandoah, Pa. Chemical engineering design of this plant was the responsibility of Francis I. and Hubert I. DuPont. Heavy-liquid separation of coal almost achieved commercial status at this plant which actually processed over 20,000 tons of coal. The liquids used were tetrabromethane, pentachloroethane and trichlo-roethylene, with liquid losses ranging from 8.9 to 12.4 oz per ton of cleaned coal. The reasons for failure of this plant are not clear but probably involved toxicity problems as well as other problems in chemical engineering. Excellent economics were reported. A more recent pilot plant was built in 1954-55 by Norris Goodwin for the Inerto Co. to treat hectorite clay. This plant employed carbon tetrachloride in jigs with liquid recovery by evaporation. Although good separation was achieved, incomplete removal of the CCl, from the clay prevented commercial operation. The only present operations known to the authors employing heavy liquids for gravity separations are limited to the use of calcium chloride in certain coal washers and bromochloromethane in a small batch operation (one ton solids per day) for the separation of beryllium metal particles from slag materials. This is not strictly a minerals beneficiation problem but it has demonstrated the feasibility of such separations. PROBLEMS Critics of early attempts to commercialize heavy-liquid separation of minerals summarize the draw-

Jan 1, 1963

By Chester T. Sims

RECENTLY, a new type of superalloy material called TD Nickel* has been marketed.&apos; It is a sim- ple, two-phased alloy, consisting of thoria particles dispersed in nickel of rather high purity (Ni-2 pct Thoz). Its mechanical properties appear relatively superior to previous experimental material attempting to use the oxide nonmetallic dispersion concept (except SAP), and superior to conventional nickel-base alloys at high homologous temperatures. This is derived from an interesting method of creating the dispersion, arising during chemical processing of the nickel and thorium salts in solution while reducing the nickel to metal. An evaluation of the thoria phase was conducted at this laboratory. Material and Procedure. TD Nickel was made available, consisting of several inches of 0.470-in. rod, extruded at a ratio of 64: 1, straightened, and centerless ground. Property determinations on this rod by the supplier at 1800°F showed an ultimate tensile strength of 11,400 psi, yield strength of 9600 psi, and 6 pct elongation. Specimens were removed from the rod for as-extruded metallography, and two 1/2-in. lengths supported on high-purity Al2O9 bricks were placed in a laboratory muffle furnace for exposure at 2000° F. The furnace door was left cracked to allow a slight amount of circulation. One specimen was removed at 200 hr for examination; the other was left for 2000 hr. Metallography. The micro structures obtained for the three conditions of exposure are shown in Fig. 1. Elongation of the grain structure in the extrusion direction is readily evident. The grains appear to be up to 0.001 in. (0.003 cm) long, with a length/width ratio of about 10: 1. Allowing for modest local in-homogeneities in structure, no significant change in thoria particle size or nickel alloy grain size occurred during the 2000°F exposure. However, etching depth varies slightly from one specimen to another, changing the number of particles visible. The thoria dispersion appears to be in the order of 0.01 (min) to 0.5 (max) p diam. The minimum diameter is difficult to estimate at X10,000, and may be less. Interparticle spacing appears to be about 0.1 p. Etching effects can be seen, depending upon grain orientation. A cubic etch-pit pattern appears in certain grains, apparently when etching is started by an anodic particle of thoria, Fig. l(c). The cubic pattern appears related to crystallographic orientation, and is prominent when the [ l00 ] direction is perpendicular to the plane of polish. The grains which present a ridged appearance in the photograph appear to be oriented with the [110} direction perpendicular to the plane of polish. Analysis. The thoria particle size was measured by a line intercept method perpendicular to the extrusion direction. Only particle sizes measuring 0.001 in. at X10,000 or larger could be extimated. Within limits of experimental error, particle size distribution appears to be unaffected by exposure, Fig. 2. To check structural stability further, a grain-growth evaluation was made. The number of grain-boundary intersections was counted at X500 on each of several traces normal to the extrusion direction for each condition. It can be seen from Table I that grain diameter appears unchanged by the 2000°F exposure. The slightly finer grain diameter after 200 hr may be attributed to variations in grain size from area to area in the original extrusion. From the present rather limited study of Ni-2 Th on, it appears that: 1) for time-temperature exposure up to 2000 hr at 2000°F (Larsen-Miller parameter = 57, homologous temperature = 0.8) thoria particles of the size studied are highly thermally stable; they do not significantly react, agglomerate, or diffuse; and

Jan 1, 1963

By E. E. Wark, J. Rogers, I. W. Wark, K. L. Sutherland

SOAPS have been used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xanthates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present eminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies.[t] A broad, semi quantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. THE PARAFFIN CHAIN SALTS The basic requirements for a "collector" in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polarnonpolar compounds is the paraffin chain salts: CH3(CH2) „X where X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -CO2Na, -SO3Na, -SO4Na, - PO4Na2, or an aminonitrogen group, the

Jan 1, 1946