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By H. O. Hoffman, C. D. Demond

There are two methods of determining the fusibility or refractoriness of fire-clays, the theoretical and the experimental. In the former, conclusions are drawn from the chemical composition; in the latter, from the changes which the clay undergoes when subjeoted to intense heat. It is well to use both methods, beginning with the actual heat-test and explaining the results obtained from this by the help of the chemical analysis. In discussing the subject, however, it is better to reverse this order. I. The Theoretical Method.* Leaving out the hygroscopic and combined waters and any organic matter, as not directly affecting the fire-resisting property, the refractory constituents of fire-clay are alumina and silica, and the fluxing constituents magnesia, lime, soda, potash and ferric oxide. According to Bischof,† alumina is the least fusible component, and silica follows close upon it. If, however, a mixture of the two be heated, it will be found that its melting-point is much lower than that of alumina, as a silicate will then have been formed. The way in which silica affects the refractoriness of alumina has been strikingly presented by Seger 1 in a diagram reproduced in Fig. 1. The abscissæ represent the melting-points of Seger cones Nos. 26 to 36 (see p. 55); the ordinates, the relative amounts of alumina and

Jan 1, 1895

By K. G. Davis

Dilute alloys of silver and of thallium in tin have been solidijzed unidirectionally under controlled conditions, to study the segregation associated with a cellular interface under conditions where both thermal and solute convection are present. Autoradiography and radioactive tracer counting techniques were combined with electron-probe microanalysis to study both macro- and microsegregation. It was found that, for concentrations giving only small amounts of constitutional supercooling, cell formation had little effect on the macroscopic distribution of solute along the specimen. At higher concentrations the effective distribution coefficient was higher than that expected for a smooth interface. Node spacing was independent of initial solute content at lower concentrations, becoming greater as keff increased. Silver content at the segregation nodes of silver in tin alloys was independent of initial concentration and considerably in excess of the eutectic composition. SINCE the investigation of cell formation at advancing solid-liquid interfaces by Rutter and Chalmers,' a large volume of work has been dedicated to the determination of solidification conditions under which a planar interface will break down into cellular form. Early experiments were explained satisfactorily by the concept of constitutional supercooling,2 but, due to poor measurement of temperature gradients in the liquid, lack of accurate data on liquid diffusion and equilibrium distribution coefficients, and uncertainty about the effects of thermal and solute convection, these experiments cannot be used as proof for the theory. More recent work, however, has shown that under conditions where convection is eliminated or can be ignored good correlation is observed.3,4 Investigations into segregation at cell caps5 and at cell nodes6-'' have been made, but no measurements appear to have been done on the overall, macroscopic segregation down a unidirectionally solidified rod of material which has solidified with a cellular substructure. This has practical importance in casting, where regions of material with cellular substructure are often encountered, and also in zone refining where the thermal conditions necessary for a planar interface are unattainable. Further, as will be shown, the macroscopic segregation can give information on the following question. Granted that a cellular solid-liquid interface develops from a planar one when the conditions for constitutional supercooling are exceeded, how much supercooling is present after the cells have formed? EXPERIMENTAL PROCEDURE AND RESULTS Specimen Preparation. Specimens 25 cm long with a square cross section 0.6 by 0.6 cm were grown in graphite boats by solidification from one end. Alloy compositions are given in Table I. Two specimens of each composition were grown. The tin was 5-9 grade and the silver and thallium both 4-9 grade. Ag110 and Tl204 were used as tracers. Each composition had the same quantity of tracer so that auto radiographs of specimens containing different concentrations of the same element could be easily compared. Thermocouples inserted through the lid of the boat into a dummy specimen showed that, over the first 10 cm of growth, thermal conditions were quite steady, with a rate of interface advance of 5.8 cm per hr and a temperature gradient in the melt ahead of the interface of 3.0°C per cm. The specimens were seeded from tin crystals of a common orientation to eliminate orientation effects. Dilution of the specimen by seed material was minimized by the provision of a narrow neck between specimen and seed crystal. Macrosegregation. After growth, the specimens were sectioned with a spark cutter. The rods of silver alloy were cut into 1-cm lengths and analyzed for Ag110 using a y -ray counter with fixed geometry. The specimens containing thallium were cut into 2-cm lengths and analyzed for T1 204 by taking 13 counts from each end of the cut lengths through an aperture in lead sheet approximately 0.4 cm square. The results are summarized in Figs. 1 and 2. To find the effective distribution coefficient for the silver in tin alloys under smooth interface conditions, the region of substructure at the bottom surface of one of the 10 ppm specimens, see Fig. 3, was removed by spark machining before counting. Autoradiography. For both alloy systems the samples were polished on sections taken alternately parallel and perpendicular to the growth direction, and autoradiographed by placing the polished surfaces in contact with Kodak "Process Ortho" film. Figs. 3 and 4 show the structures revealed. The alloy containing 10 ppm Ag showed substructure only after a few centimeters of growth, and then substructure was limited to a narrow layer at the base. The "speckled" substructure reported previously in this system4 is here clearly seen to be an intermediate stage between planar and cellular interface conditions. The other samples show a remarkable similarity considering

Jan 1, 1969

By Clyde Williams

IN this war as in no former one, the use of metals has been the major factor governing success. For building new plants, new transport facilities whether by land, sea, or air, for our mechanized army, and for nearly all weapons, iron and steel has provided the basic material. Being the world leader in iron and steel production in peacetime, we soon adapted plants to production for war. Starting with a production of 66,000,000 tons of steel ingots in 1940 from a rated capacity of 80,000,000 tons which only could be reached by straining every productive device available, our industry expanded to 86,000,000 tons in 1942, and ultimately to 96,000,000 tons. To do so required expansion of every unit operation including mining, rail and water transportation, blast-furnace and steelmaking facilities, and rolling mills. New plants not only had to be built in record time but more output for each operation was essential. This performance required skillful operation and engineering techniques and also a better understanding of the physics and chemistry underlying such complex operations as the working of a big blast furnace. A vastly increased pig iron production made possible the great output of steel by an industry that had depended on scrap for its basic raw material even though sufficient scrap was unavailable. This was done by conversion of pig iron in the Bessemer either into steel or into a low-carbon product that was subsequently used in place of scrap in the open¬hearth steel furnace. Furthermore, by duplexing from the open-hearth to the electric furnace, and the construction of many new electric furnaces, our output of electric-furnace alloy steel was greatly increased. Moreover, techniques were developed by which alloy steel could be made in the open hearth with the result that our production of alloy steel reached the fantastic figure of 15,000,000 tons a year.

Jan 1, 1945

By E. H. Griswold, C. E. Beecher

DURING 1931 the petroleum industry has faced the most hazardous periods of its existence, caused by large potentials, overproduction, and demoralized markets. Two state governors actually resorted to the use of the militia in an effort to restore a semi-stabilized condition within the industry, to prevent waste of the states' natural resources, and to restore prices to a level that would yield the states a reasonable tax revenue. These conditions have made it necessary to put into effect most. stringent economies and have produced a spirit of cooperation between companies to an extent that never before existed. The necessity for unified action on such matters as proration and the advantages to be gained by unit operation are being realized by the oil industry as a whole. Fewer wells have been drilled and wildcat operations almost eliminated: development and operation costs have been greatly reduced and more attention is being paid to efficient recovery methods. The net work of oil pipe- lines has grown rapidly especially in the area of East Texas. The construction and operation of natural gas and gasoline pipelines into areas far distant from the source of supply has been one of the outstanding accomplishments. Refining efficiency has continued to increase and the public is being supplied with a better grade of gasoline at a lower price. The unreasonable tax which state politicians have succeeded in placing on gasoline has encouraged tax evasion and unfair competition by un- scrupulous dealers and has misled the public as to the true price of gasoline.

Jan 1, 1932

By C. H. Cheng, C. E. Birchenall

The fundamental problem in the thermodynamics of solid solutions is the determinatiorl or calculation of the activities of the components as a function of temperature and composition. Since the theory of metals is not suficiently developed to allow a priori calculation of these quantities, they must be obtained from experiment. C. Wagner1 has reviewed the literature of this subject for the period before 1940. Although several important and extensive studies have been made in the meantime, the number of systems to which any sort of quantitative information can be assigned is vanish-ingly small. These data have become of great potential importance in studies of the structure of solid solutions2 and intermetallic compounds, the nature of the diffusion process,3,4 and perhaps even the mechanism of mechanical deformation.5 For these reasons, it. seems very worthwhile to extend the experimental data in this field. Although there is little use in duplicating Wagner's review, attention should be directed to the most recently reported investigations. A brief enumeration of the methods of measurement previously employed also should be valuable. The most direct method is the determination of the partial pressure of the components in the vapor phase in equilibrium with the solution. Both equilibrium and kinetic methods have been tried in metal systems, but almost exclusively on liquid phases. Only in the ease of carbon in iron alloys and in the copper-zinc system have extensive measure- ments been made which include solid phases. When one of the components is an element, such as nitrogen or carbon, which forms compounds which are very volatile and stable at normal temperatures and pressures (CH4, Co2, CO NH3), it is frequently possible to equilibrate mixtures containing these (such as CH4-H2, CO2-CO, NH3-H2) independently with the elernents (C, X) and with the metal (Fe, Ni, etc.). Such measurernents have been made for carbon in iron, iron-silicon, and iron-manganese alloys by Smith6 and in iron and iron-nickel alloys by Toensing.7 Differences between carbon activity values at the same temperature and carbon content when carboil is introduced from CH4-H2 rnixtures or CO-CO. mixtures indicate that the effects of hydrogen and oxygen in the system are not negligible, and one can only hope that the true value lies somewhere between these sets of results, probably nearer the CH4-H2 data since hydrogen is less soluble in iron than oxygen. This is essentially an equilibrium method, although flowing gas is employed. A kirletic method has been employed which consists of sweeping an inert gas (generally hydrogen) over the alloy at a series of rates, condensing the metal vapor out,, and analyzing it. The metal content can be extrapolated to zero flow rate (equilibrium). Wejnarth's8 work on Cd-Mg and Zn-Mg is a good example of this frequently used method. A variant of this consists of equilibrating a known volume of inert gas with the alloy, sweeping it out quickly, and analyzing for metal. In common with the above method, it has the disadvantage that the "inert" gas is generally somewhat soluble in the alloy. Moreover, the former continuously displaces the system from equilihrium and may give low values if solid diffusion is involved. The dew point method applied by Hargreaves9 to the alpha and beta brasses and by Schneider and Stolll0 to A1-Zn avoids the introduction of another component to the system, but is useful only in systems in which one component is much more volatile than the other. The alloy sealed in one end of an evacuated silica tube is heated to the desired temperature. The temperature of the other end is lowered until droplets of the volatile component condense. When the temperature is raised slightly, the droplets will evaporate. By careful adjustment of temperature, the range between evaporation and condensation can be narrowed appreciably. An independent determination of the vapor pressure of the . pure volatile component is necessary to give the partial pressure over the alloy. This is the method employed here to determine the vapor pressures of zinc and cadmium over their silver alloys up to 34 pct in cadmium and 76 pct in zinc. The former involves only the a solid solution, but the latter covers the a, ß, y, and e fields. In recent determinations, Herbenar, Siebert, and Duffenbarkl1 used the

Jan 1, 1950

By William F. Boericke

THE Christy Creek clay mine of the General Refractories Co., in the Olive Hill District, ranks with the most important producers in the north-eastern Kentucky fire clay field, both from production of high-grade flint clay, as well as unusual extent and thickness of deposit. The property is but one of a number controlled by the General Refractories Co. in this district, but is given first consideration among them by the operating staff. Its total area is over 5000 acres, owned in fee or by lease of clay mining rights, and although mining operations have been in progress for over five years, scarcely one per cent of the ground has been worked as yet. The mine is near the southwestern end of the clay field, which extends in a belt 12 miles wide and 55 miles long, in a southwestern direction from Kenova, W. Va., which, as the name indicates, is at the junction of Kentucky, Ohio, and West Virginia. Olive Hill, where there is one of the l1Ulin plants of the General Refractories Co., and to which the clay from the mine is shipped, is about 26 miles distant from the mine. Connection is made with the Chesapeake & Ohio R. R. by a spur line . 8 miles in length, owned and operated by the company.

Jan 1, 1929

By James R. Garvey

Coal reserves of the United States are enormous. Considered on the basis of proven reserves, and compared with reserves of other fuels, coal constitutes 88% of the proven recoverable energy resources of the nation. That includes oil, natural gas, oil shale and uranium used in burner reactors. Considered on the basis of "ultimate recoverable reserves", that is, those resources which can be extracted with improved technology and at somewhat higher costs and including those resources of all fuels not yet found but believed to be waiting discovery, coal still accounts for 75 % of the national total. In the U.S. hydrocarbon economy about 76% of the total energy needs are supplied by petroleum and natural gas and about 20% by coal. Domestic resources of oil and gas are running dangerously low, and assuming a continued hydrocarbon economy, the 20% supplied by coal may increase dramatically. Nearly a quarter of the petroleum consumed in the U.S. is imported. Natural gas is in shorter supply than petroleum and the problems of its importation seem at least as difficult as those of oil.

Jan 6, 1972

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the first half of March: James C. H. Ferguson, San Francisco, Cal. Capt. A. F. Lucas, Washington, D.C. Henry Adams, Stamford, Conn. Dexter P. Cooper, New York, N. Y. H. A. Wheeler, St. Louis, Mo. L. D. Moore, Chatham, N. J. John M. Sherrerd, Easton, Pa. Hennen Jennings, Washington, D. C. R. T. White, formerly General Manager of the Braden Copper Co., Chile, is to take charge of a copper company in Caucasus, South Russia.

Jan 4, 1914

Polluted air and water, despoiled land and excessive noise are the unwelcome results of the population growth and a rising standard of living. The consumption of goods and services, including metal products and minerals, by all people is increasing so rapidly that civilization is in danger of destroying the environment in which it lives. This is true because every human activity affects the environment, whether it is air, water or land. While E. F. Osborn, director, U.S. Bureau of Mines, says . . . "some members of the mineral industry are reluctant to recognize environmental demands" . . . William T. Pecora Under Secretary of the U.S. Department of the Interior.. . says that, "to maintain levels of resource development and environmental quality needed to satisfy our affluence, we must trade off values rather than turn off troublesome operations." What it seems to boil down to is how much control of its operations is the mineral industry willing to accept-internal policing or strict government control? The answer lies in how well the mineral industry maintains a balance between mineral development and environmental quality.

Jan 1, 1971

By Emil Gathmann

STEEL as it is poured, or teemed, into the mold for forming the ingot may be broadly separated into two divisions; i.e., effervescing or gassy steel, also termed evolution steel, and non-effervescing or killed steel, also termed solution steel. Between these primary divisions there are various types having the characteristics of both divisions but really not belonging to either; such steels are termed semi-piping, rising, or wild, as the type may be. True unkilled, or effervescing, steel should contain large volumes of gases, which are evolved while the metal is being teemed, or cast from the ladle nozzle into the mold, and while the temperature of the steel is being reduced prior to the solidification or freezing of the steel, the upper portion, or top, of the ingot remaining liquid due to the evolution of gases until an ingot skin of considerable thickness has been formed. These gases consist principally of hydrogen, carbon monoxide, nitrogen, and ammonia. It is generally understood that nitrogen gases are the first evolved and form the skin blowholes, at times troublesome, in the forming solidifying ingot. Ingots made of effervescing steel will always contain a large number of blowholes. Such blowholes are not deemed objectionable in various products if they occur well within the interior of the ingot where they will not be subject to oxidation upon the ingot's cooling and subsequent re-heating and rolling or forging. Very little top or bottom discard is taken from this type of ingot as pipes, or large shrinkage cavities, at the upper portion of the ingot do not usually occur, the difference in volume between the liquid and the solid steel (6 to 10 per cent.) being compensated for by the innumerable blowholes distributed throughout the body of the , ingot. Of the 40,000,000 tons of steel made in the United States during the year 1919, at least 35,000,000 tons of ingots were made of gassy or semi-gassy steel. Killed, or solution, steel is termed true piping steel from the characteristic pipe or shrinkage cavity that usually occurs in the uppermost central portion of the ingot.

Jan 8, 1920

By M. C. Flemings, G. E. Nereo

General expressions are given to describe macro-segregation in castings and ingots which results from mass flow of solute-rich liquid to feed solidification and thermal contractions. Analytical solutions are given for solidification with planar isotherms (unidirectional and bidirectional heat flow). These solutions describe inverse segregation and centerline segregation. Numerical examples are given for A1-4.5 pct Cu alloy. In 1540, Vannoccio Biringuccio published one of the first references to macrosegregation, describing the problem of exudation and inverse segregation in the manufacture of bronze gun barrels.' Since then, a great many studies of macrosegregation have been reported. Recent work of particular engineering interest includes that of Marburg 2 and others:" on centerline segregation and other types of segregation in large steel ingots, and work of Adams,5 Scheil, 6 and Kirkaldy and youdelis7 on inverse segregation in nonferrous ingots. In most studies on this subject, the various types of macrosegregation have been treated as separate phenomena. For example, quite different mechanisms have been proposed for formation of centerline segregation, negative cone of segregation, inverse segregation, banding, and so forth. In this, and in several papers to follow, it is proposed that these as well as other types of macrosegregation result from the same basic mechanism and can be quantitatively described by the same basic equation. It has often been suggested that some types of segregation (such as centerline segregation and banding) occur as a result of buildup of solute at the tips of growing dendrites.2-4 ,8-10 As example, banding can be induced in centrifugal castings by mechanical vibration, and Northcott 10 suggests this might be due to the influence of the vibration on the boundary layer at the dendrite tips of the growing dendrites. However, in view of the extremely small boundary layer known to exist at the tips of the dendrites,11,12 any interpretation of macrosegregation based on this boundary layer is clearly incorrect. Note that experiment has shown that significant buildup of solute does not occur at dendrite tips in ingot solidification, but even if such buildup occurred the thickness of the enriched zone would only be the order of D/U where D is liquid diffusion coefficient and U is dendrite tip velocity. For usual casting or ingot solidification this solute-enriched layer is 10"3 cm, far too small to account, for example, for centerline segregation.11'12 It has also been suggested that convection in the bulk liquid (ahead of the advancing dendrites) might cause segregation by sweeping away the solute-rich boundary layer in front of the dendrites.3 However, since there is no significant boundary layer, this explanation must be incorrect. The convection might directly cause segregation by penetrating between the dendrite arms, and presumably in a rimming steel ingot it is sufficiently vigorous to cause some segregation in this way. Centerline segregation, however, cannot be interpreted as resulting from this convection since a sharply segregated zone is usually found near the centerline, with the bulk of the ingot being nearly of nominal composition. If convection in the bulk liquid were the direct cause, a gradual change in ingot composition over the entire cross section would be expected. It is known that sudden changes in convection of the bulk liquid during solidification can result in banding,14 but it is not clear that the banding results directly from the effect of convection on solute distribution. Changes in convection also affect thermal conditions in the liquid-solid region of a solidifying ingot. It will be seen later in this paper, and in a paper to follow, that macrosegregation is strongly influenced by these thermal changes. Recognizing that in some cases of ingot solidification (as in solidification of rimming steels) convection in the bulk liquid may have a direct effect on solute distribution, we neglect it in this paper and in the several to follow. We then derive general expressions describing macrosegregation which results from the mechanism of interdendritic flow of solute-rich liquid

Jan 1, 1968

A comprehensive, systematically structured mineral evaluation system is a prime requirement for objectively assessing mineral supply impacts on the economy. The Minerals Availability System developed by the US Bureau of Mines is a step in the right direction-a well-organized unraveling of the mineral supply network, structured in format to allow quick retrieval for rapid listing, supply analysis, and other uses.

Jan 9, 1977

TULSA SECTION At the smoker concluding the two day meeting of the Tulsa section of the American Institute of Mining and Metallurgical Engineers, Tulsa, Okla., Feb. 26, 1919, Dr. Willis T. Lee, the new head of the Geological Department of the University of Oklahoma, was introduced to the assembled geologists and mining engineers. Dr. Lee requested that the geologists and engineers who were making a specialty of petroleum geology assist him in giving a good course in practical oil geology in the Geological Department of the University. After a motion offering the services of all present in giving lectures on their special subjects had been adopted, Dr. Perrine of Hutchinson, Kans., named the geologists who were pledged to give lectures in Dr. Lee's course. The students in geology at Norman are assured of the latest information regarding practical work in petroleum geology and will have the inspiration derived from contact with men who are actually at work upon the problems which they are studying. Dr. Lee and President Brooks of the University are to be congratulated upon the introduction of this .method of instruction. The plan thus put into operation is similar to the graduate system of coaching in athletics followed at many of the large universities; what is good for instruction in athletics should also prove good for instruction in applied geology.

Jan 6, 1919

By William L. Payne, Edward E. Ives

A unique feature of Potash Co. of America's A new potash property near Saskatoon, Sask., is the use of semi-dome-shaped buildings for product storage. Four domed structures, timber-framed and corrugated-sheet covered, are being built; each designed to handle 20,000 cu yd. The relatively small capacity units, PCA believes, give flexibility not only in storing different grades and sizes of product, but also in permitting greater ease in shipping products as market demands change. The domed buildings are 150-ft diam, comprised of a 16-ft-high concrete wall base, topped with a metal sheet-covered octagonal timber frame. The dome of each unit is designed to fit very closely the angle of repose of the contained material, which results in the maximum usable volume. The entire roof is flood coated with a bitumin to provide a complete weather seal.

Jan 9, 1959

By C. P. Karr

FOR several years, the Bureau of Standards has been working in cooperation with an Advisory Committee on non-ferrous metals on various phases of the production and testing of zinc bronzes. The work has dealt, especially with the type of metal known as "Admiralty bronze" in England and as "Government bronze" in this country and consisting of 88 copper, 10 tin, and 2 zinc. Several reports have been made on this subject and these should be considered in connection with this paper.1 FIRST SERIES OF FIVE FOUNDRY TESTS A very brief summary of the first series of five foundry tests has been made,2 but for the sake of clearness the results are given here in different form. The five foundries cooperating in this investigation were: Ohio Brass Co., Mansfield, Ohio; Titanium Alloy Mfg. Co., Niagara Falls, N. Y.; Packard Motor Car Co., Syracuse, N. Y.; National Cash Register Co., Dayton, Ohio; Bureau of Standards, Washington, D. C. The object of the work was to determine whether uniform results could be obtained with this alloy in different foundries working under definite instructions. One of the participating foundries prepared, from virgin metal, a stock of ingots of the composition 88 copper, 10 tin, 2 zinc, and at the same time poured nine test bars from this melt of virgin metal. The results of the physical tests of these bars are shown in Table 1. Examination of this table shows that the highest and most nearly uniform results were obtained when the virgin metal was cast flat in chill molds and the lowest and most variable results were encountered when it was cast vertical in green-sand molds. In this, as in all other tables, the mean

Jan 9, 1919

By E. O. Fromm, R. I. Jaffee, R. M. Evans

IN connection with a research on gallium alloys, a method for the thermal analysis of very low melting alloys was developed, which appeared to be worthy of more than passing interest. As used, the method was suitable for work in the temperature range, — 72° to 250°C. However, with suitable adjustment, the method could be adapted for use over broader temperature ranges. The Rosenhain temperature gradient furnace,' adapted for low-temperature use, was the basis for the method. The gradient was set up in a stainless steel tube. The specimens were lowered through it at a constant rate while time-temperature or inverse rate data were taken. It was essential to maintain careful control of the top and bottom temperatures of the gradient. Also essential was good heat transfer from the walls to the specimen. This was accomplished by a liquid heat-transfer medium.

Jan 1, 1953

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of March, 1913 BAECHTOLD, CHARLES A., Engr 9G Liberty St., New York, N. Y. BRANTLY, JOHN E., Instructor in Geology Tuscaloosa, Ala. CADDY, JAMES P., Net., ,Lake View & Star, Ltd Fimiston, West. Australia. LONERGAN, PHILIP J., JR., Prof. of Mining, Government University, Peking, China. MCKANNA, EDWIN A., Min. Engr P. 0. Box 834, Oklahoma City, Okla. MACDONALD, ANGUS W., Supt. Labor Dept., Dominion Coal Co., Ltd., 21 Queen St., Sydney, N. S., Canada. TSUBOI, Yoshio, Min. and Met. Engr., Kosaka Mine, Fujita Co., Akita-ken, Japan.

Jan 4, 1913

By G. L. Hundley, R. E. Mussler, D. H. Yee, F. E. Block, R. S. Olsen

An anhydrous chlorination process for the recovery of copper from chalcopyrite was investigated. Pelletized concentrate was reacted continuously with gaseous chlorine in a vertical shaft reactor at 550° and 650°C. While the copper was withdrawn with the rest of the metals as molten chlorides from the bottom, 99-x% sulfur was distilled from the top of the reactor. The molten metal chlorides were pulverized and dropped continuously into an upward flowing stream of oxygen. Over 80% of the iron chlorides were converted to oxides in a vertical free-fall reactor at 800° and 900°C while the copper chlorides passed through unoxidized. Copper was recovered in powder form by electrowinning continuously from chloride solutions using a diaphragm cell. The product sloughed easily from a titanium cathode and showed no iron contamination. Current efficiencies and power consumptions averaged 77% and 1.24 kw-hr per lb.

Jan 1, 1974

By Geo. H. Eldridge

This sketch of the Florence oil-field, presented to the Institute by permission of the Director of the U. S. Geological Survey, is accompanied with a map, Fig. 1, the topography of which has been taken from a field-manuscript of the Survey. The scale of the map and

Jan 1, 1892

By Walter B. Lenhart

Introduction and Importance of the Industry Sand, as described in this chapter, is a crude product used for ballast on railroads and highways, and as the fine aggregate in concrete, mortar, plaster and in asphalt paving materials. The sand used in glass, as a molding sand, and as a source of silica is described in Chapter 43. Sand and gravel together constitute the mineral raw materials of largest volume produced from the earth. In 1958, as reported by the U.S. Bureau of Mines,21 680,080,000 tons of sand and gravel (including industrial sand) were produced in the United States. The nearest competitor was crushed rock of which 532,818,000 tons were produced. Coal, both bituminous and anthracite accounted for only 431,616,689 tons in the same year. In dollar value, sand and gravel were exceeded only by cement, crushed rock and fuels. Hence it is a major unit of the mineral-producing industry. As an example, one plant in California operates around the clock at an average rate of 1,500 tons per hour, and at peak intervals has shipped over 4,000 tons per hour, all by trucks. Nevertheless, it is controlled by one man through a panel of push buttons that control the crushing, screening, washing, grading, stock piling, and reclaiming of the products. Because sand and gravel are low-valued commodities, but are used in every construction undertaking in every city, village, farm, dam and highway, they are produced in almost every county in the United States and southern Canada, by thousands of individual operators, very few of whom operate in more than one community. Many operations, particularly those established to supply the needs of major dams that are under construction, or of major segments of new highways, are temporary in nature, and the equipment installed is more or less portable. Because of the bulky nature of sand and gravel, there is very little interstate movement, and almost no exports or imports, except a little movement back and forth across the border of the United States and Canada. First, the material needs definition. Definitions Sand and gravel have been defined as continuously graded unconsolidated materials that appear in the earth's surface as a result of the natural disintegration of rocks. Both normally appear together, but in a wide variety of sizes, types and range of size classification. The American Society for Testing Materials has tentatively revised its definition of "sand" as: granular material passing the 3/8-in. sieve and almost entirely passing the No. 4 (4760-micron) sieve and predominantly retained on the No. 200 (74-micron) sieve, and resulting from natural disintegration and abrasion of rock or processing of completely friable sandstone (ASTM Designation C 58-55T). The Society's tentative revision of its definition of "gravel" is: granular material predominantly retained on the No. 4 (4760-micron) sieve and resulting from natural disintegration and abrasion of rock or processing of weakly bound conglomerate (ASTM 125-55T). Sand and gravel deposits contain materials from the finest silt to the largest boulders. Chemical definition of the two materials is nearly impossible. Sand and gravel always are

Jan 1, 1960