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By W. J. Taylor

In making heating gas with anthracite coal for roasting ore during the past few years, I have tried many forms of gas generators. So far, the most successful and satisfactory one has been what we call a fluxing producer, which is simply a small cupola or blast furnace, in which we charge with the coal, say, 30 or 40 per cent. of basic blast-furnace cinder, to unite, when melted, with the ash or earthy matter in the coal, and carry it off as cinder. The producer we have in use at Chester, N. J., has more of the lines of a blast furnace than a cupola, the hearth being 24 inches diameter and 24 inches high. It then enlarges on an angle of about 25 degrees from a perpendicular to 4 feet, and then is drawn into 3 feet on top ; total height, 12 feet. We use one water coil-tuyere 12 inches above the bottom, and blow through a 1 1/2 - inch nozzle. The depth of coal above the tuyere averages about 6 feet. The producer-is blown with

Jan 1, 1881

By D. L. Wood, J. H. Westbrook

The tensile behaviors of the CsCl structure compound AgMg are extensively documented in terms of strain, strain rate, temperature, composition, and metallurgical processing treatment. The observations lend themselves to presentation in terns of three regimes of deformation behavior; 1) low temperatures where deformation is primarily by slip; 2) intermediate temperatures where the deformation mode is also slip but with the detailed behavior dominated by dislocation interactions with solute atoms; 3) high temperatures where defomation is primarily by diffusion controlled processes. Of all the material groups of potential interest as high-temperature structural materials, the inter-metallics have been the least studied, particularly with respect to their mechanical behavior. Moreover, the application and processing of intermetallics for uses which exploit their often unique physical properties have been impeded by a lack of understanding of their mechanical properties. Previous work in this area* has been largely *For a recent review, see Westbrook.' exploratory, aimed on the one hand at the direct empirical development of materials of engineering utility and ,on the other at identification of the important parameters affecting the mechanical behavior of inter metallics. As a consequence, there has not been available, heretofore—for any inter-metallic—data, sufficient in extent or precision to provide an adequate phenomenological description of the effects of metallurgical variables on deformation behavior. Such documentation is prerequisite to intelligent application or processing design and is also necessary for testing present and future theoretical analyses of mechanical behavior. It was therefore an objective of the present investigation to document the deformation behavior of a simple ordered intermetallic over as wide a range as possible of all the usual metallurgical variables. The compound AgMg was chosen as the subject of this investigation because it met all of a group of desired criteria, namely: 1) congruent but moderate melting point; 2) simple crystal structure; 3) ordered structure persisting to the melting point; 4) broad solubilities for the component elements. The first and last criteria were expected to aid in the preparation of homogeneous single-phase specimens: the second and third to help simplify the

Jan 1, 1962

By Robert Glass Cleland

IN gathering material for this book, I have made extensive use of the archives of Phelps Dodge, contemporary news- papers, and a wide range of secondary sources. Two manuscripts-one on the history of Phelps Dodge by Arthur Train, Jr., and John L. Lawler, the other a biography of William E. Dodge by Richard Lowitt-have been of the greatest value. I owe a particular debt to the authors whose names I have just mentioned. I have also gathered important information and obtained revealing points of view from conversations with many people. Personal visits to the company's mines and plants added knowledge and understanding that nothing else was able to supply. I am greatly obligated to the officers of the company, especially to Mr. Louis S. Cates, chairman of the board of directors, Mr. Robert G. Page, president, Mr. George R. Drysdale, vice-president of Phelps Dodge Corporation, and Mr. Walter C. Bennett, president of Phelps Dodge Refining Corporation, for their co-operation and assistance. Mr. Wylie Brown, former president of Phelps Dodge Copper Products Corporation, also supplied valuable data and deeply appreciated hospitality. In my visits to the Phelps Dodge properties, company representatives extended every hospitality and placed at

Jan 1, 1952

By Blamey Stevens

My previous paper is entitled, The Laws of Igneous Ernanation Pressure. The present paper lays no claim to the exactitude and completeness of a law, since it is of a provisional nature and may be disregarded when experiments have established a basis for more exact reasoning. The general physical states in which aqueous emanations may occur are first considered. The possible physical couditions under which the mineral elements may occur in emanations are then discussed, and a classification of deposits, dependent on emanation, is proposed. A system of scientific experimental investigation is outlined, and it is shown that the physical and chemical properties of emanation may be exactly determined thereby. The investigation is urged as feasible and simple, and not necessarily requiring large and costly apparatus. It is the only step necessary to make possible the formulation of a complete set of laws of igneous emanation. Process of Emanation. In a rising column, magma ranges in temperature from 900° to 1,200°C. Exhalation must begin at some fairly great depth. What this depth may be we can only surmise, since no experimental evidence is available. Exhalation, however, continues as the magma flows upward, until at another level the occluded gases have all escaped. This depth is probably upward of 5,000 ft. (See Fig. 1.) All exhalations must come from between these two levels. As the whole emanation is the sum of the exhalations and residues, the residues must come from below the uppermost level. They will be most abundant when coming from those parts of the intrusion which have solidified below the lower level.

Jan 1, 1913

Jan 1, 1961

By E. H. Jr. Crabtree

THE productive area of asphalt-bearing sandstone in Missouri is near the Missouri-Kansas state line near Nevada, the county seat of Vernon County about 100 miles south of Kansas City. While produc-tion thus far has been confined to Vernon and Barton counties, there are known deposits in adjacent counties. The area is served by four rail-roads: the Missouri Pacific, the Kansas City Southern, the Missouri-Kansas & Texas, and the St. Louis & San Francisco. The plant of the Reliance Rock Asphalt Corporation is in Vernon County, about 5 miles west of Nevada, at Ellis, a flag station on the Missouri, Kansas & Texas Railroad. A siding has been built to the plant so that the finished product can be loaded directly into railroad cars. The property consists of a lease of 240 acres in one block. All portions of the property not required for quarrying or processing the asphalt-bearing sandstone are used for farming by the fee owner. The entire tract is very flat so that there are no transportation difficulties from quarry to plant.

Jan 1, 1935

Jan 1, 1889

By E. I. Larsen

Powder metallurgy has been described as being "as old as the pyramids and yet as new as the latest bomber." While this may be true literally, it has been only in the last Io or 1 5 years that widespread use has been made of this method of fabricating various articles One of the first items fabricated by powder metallurgical methods on a commercial scale was electrical contacts, which were fabricated from metal powders as early as 1920. The reason why these contacts have been made for so many years by powder metallurgy is because the compositions of most of these materials arc such that they could not be made by the conventional methods of melting, casting, rolling, drawing, etc. Classes of Contacts In general, electrical contacts fabricated from metal powders fall into two classes, both from the point of view of the method of fabrication and the components that make up the chemical composition. One class is composed of silver or copper and a refractory metal such as tungsten, molybdenum, or compounds thereof such as carbides. The second class contains a predominant amount of silver and a semi-refractory material such as cadmium oxide, nickel, cobalt, or graphite. Electrical contacts of the first class have been developed primarily as facing materials for heavy-duty circuit-interrupting devices. This class of material unites the high melting point, high boiling point, great resistance to electrical erosion, and the refractory characteristics of molybdenum, tungsten, or their carbides with the high thermal and electrical conductivities and low contact resistance properties of silver or copper. The second class of material is used for lighter duty or specialized applications such as heavy-duty, direct-current aircraft relays. Varieties Electrical contacts fabricated from metal powders are made in a wide variety of compositions, shapes, and sizes. In general, the sizes of electrical contacts fabricated from powders vary from contacts weighing approximately 0.001 oz. up to those weighing 3 to 4 Ib., the contacting face being as small as 0.001 sq. in. up to approximately 6 sq. in. in area. The shapes consist of: sound or rectangular buttons, some of which have radii or bevels on the contacting faces; rings, cups, rectangular bars, the contact face of which may have a radius across the width and/or at one end; and form-pressed pieces of a wide variety such as angles, both acute and obtuse, irregular shapes comprising a radius blended into a flat, which in turn may have steps. The size or shape of the contact is dictated principally by the mechanical design of the manufacturer, who in turn may have problems to be met such as: (I) size, weight, or space limitations; (2) electrical conditions such as blowout coils arc chutes, baffies, gas passages.

Jan 1, 1945

By Lawrence H. Van Vlack, Otta K. Riegger

Periclase-type oxides were examined microscopically after being exposed to siliceous liquids. The rate of grain growth was found to be inversely proportional to the grain diameter. Grain growth proceeds more rapidly at higher temperatures, but is retarded by increasing liquid contents. aMag-nesiowiistites with higher MgO contents grow less rapidly than those with higher FeO contents. The growth rate is reduced by the presence of a second solid phase. The silica-containing liquid penetrates as a film between the individual magnesiowus tite grains. This is independent of time, temperature, amount of liquid, or the MgO/ Fe0 ratio. When present, olivine and spinel-type phases can provide a solid-to-solid &apos;&apos;bridge" between magnesioustite grains. THIS paper presents the results of a study of the microstructures of periclase type oxides in the presence of a silicate liquid. The purpose was to learn more about the effect of service factors such as 1) time, 2) temperature, and 3) liquid content upon A) grain growth, and B) liquid location among the solid grains. This study was prompted by the fact that periclase refractories are known to have very little solid-to-solid contact when the phases which are present are limited to periclase and liquid. Such a micro-structure gains industrial significance because it permits fracture during service when stresses are applied at high temperatures. The details of ceramic microstructures have not received extensive attention. This is in contrast to the extensive attention given to a) the phase relationships pertaining to refractory compositions, and b) the details of the microstructures of comparable metallic materials. A brief review will be made of the pertinent phase relationships and microstructural considerations in general, as well as of refractory compositions. a) Phase Relationships. This investigation was limited to those compositions in which (Mg, Fe)O was the solid phase. MgO and FeO form a complete series of solid solutions. Pure MgO has the name of periclase. The related FeO structure is called wustite. Both have the NaC1-type structure: however, wustite possesses a cation deficiency so that the true composition is Fe<10 even in the presence of metallic iron. The phase relationships involving solid (Mg, Fe)O and a silicate liquid are shown in Fig. 1. In this case. the liquid is saturated with (Mg, Fe)o. There-fore its SiOz content is below that encountered in orthosilicate liquids. As a consequence the liquid phase specie:; are primarily the following ions: and 0-&apos; plus occasional Fe+ ions. Two features are of importance: a) the liquid contains relatively small species and b) the liquid contains large quantities of the same species as the solid. viz., Fig. 2 shows the system, FeO-SiOz, which will be used in some of the discussions that follow. This diagram is the right side, vertical section of Fig. 1. Here, as pre\iously, the composition at the FeO end of the diagram is nonstoichiometric, varying from Feo.950 when the liquid oxide is in contact with the solid iron, to about Fe 0, when the solid oxide is in equilibrium with an atmosphere of equal proportions of CO and C02 at the solidus temperature. The Fe/O ratio will be maintained in wustite in the presence of SiO,. However, the FeM/Fe++ ratio in the liquid will be lower because of the effect OIF the SiO, on the activity of the FeO. With the addition of MgO to wustite, the over-all composition (IvZg, Fe)@, has a value of x lying between 0.9 and 1.0 when the COz/CO ratio is 1.0&apos;. b) Microstructures. In general, published attention to refractory microstructures has been directed toward the phase analyses that accompany compositional variations. This is illustrated by Harvey6 in his work on silica brick and by wells7 in his work on periclase brick. In each case, a series of altered zones is encountered which provides a sequence of phase associations. If due consideration is given to reaction kinetics, such an examination reveals phases that are compatible with equilibrium studies. Admittedly, however, it is often necessary to determine more complicated polycomponent systems to account for all the phases present.8 Relatively little attention has been given to microstructural geometry in ceramic materials. Certainly less attention has been given to this aspect of ceramic microstructures than to the size, shape, and distribution of the constituent phases in metals. Burke has pointed out that the grain size of oxides follows the same growth rules as for metals, viz.,

Jan 1, 1962

By R. J. Brison, O. F. Tangel

The development of a new method of mineral separation was sponsored by the International Salt Company, which requested Battelle Institute to investigate means for improving the quality and appearance of rock salt from the Company&apos;s Detroit mine. Although developed specifically for removing impurities from rock salt, the general method may be applicable to other separation problems. The principal impurities in rock salt from the Detroit mine are dolomite and anhydrite which represent 2 to 5 pct of the weight of the mined salt. In the size range from 1/4 to M in. (the range of primary interest in this project) the impurities are only partially liberated from the halite in normal production. Further size reduction to improve the liberation of impurities is not practicable in view of the market requirements for the coarse grades of rock salt. Laboratory separations in heavy liquids showed that, to improve the quality and appearance of the rock salt substantially, it would be necessary to remove not only free gangue particles but also a large proportion of the locked-in particles. Because rock salt is an inexpensive commodity, a low-cost process was required. Gravity methods were, of course, considered. The heavy-liquid separations indicated that a split at an effective specific gravity of 2.2 to 2.3 would be required. (The specific gravity of pure halite is 2.16.) Heavy-media separation was investigated but had the disadvantages that it was necessary both to operate with saturated brine and to dry the cleaned salt, and that the cleaned salt was darkened by the magnetite medium. Air tabling was tried but did not give the desired separation. It soon became apparent that established methods would not provide a satisfactory solution and work was undertaken on the development of a new process to solve the problem. PROCESS DEVELOPMENT Preliminary Experiments: At the start of the investigation, an analysis of the problem indicated that the diathermacy of rock salt—that is, its ability to transmit radiant heat—might form the basis for an efficient separation process. Under this theory, the impurities might be selectively heated by radiant heat. The particles could then be fed over a belt coated with a heat-sensitive substance so that the warm impure particles would adhere preferentially to the coating. After the initial experiments, made by heating the rock salt with an infrared lamp and separating the product on small sheets of resin-coated rubber, proved encouraging, a small continuous separation unit was set up. This comprised 1) a simple heating unit consisting of a vibrating feeder covered with aluminum foil and an infrared lamp mounted above the feeder and 2) a separation belt 6 in. wide and 36 in. long. A sketch of the device is shown in Fig. 1. Results with this apparatus confirmed the fact that a good separation was possible. It was apparent, however, that a considerable amount of experimental work would be needed to develop the scheme to a practical and economical process. The Process: Basically, the process consists of two main steps: 1) selective heating by radiation and 2) separation of the heated particles on a heat-sensitive surface. Because neither of these steps had previously been utilized commercially in mineral processing, it was necessary to do basic research on both aspects. Factors studied in the investigation included type of heat source, design of heating unit, design of separation belt, selection of heat-sensitive coating, removal of heated particles from the belt, contact between particles and coating, and maintenance of the heat-sensitive surface. Part of the experimental work was carried out on a small-scale unit consisting of the 36x6 in. belt and auxiliary apparatus, and part on a larger unit. For simplicity, discussion of work on both of these units is grouped together. SELECTIVE HEATING Radiant-Heat Source: The essential requirements for a radiant-heat source were 1) that the radiant heat be in a wave length range which is effectively absorbed by the impurities but not absorbed appreciably by the rock salt and 2) that it be dependable, practical, and economical. Selection of a heat source of suitable wave length range was one of the first considerations. It is well known that pure halite is highly transparent to radiant energy in wave lengths from 0.3 to 13 microns. However, the available data on infrared transmission by dolomite and anhydrite, particularly in the range below two microns, were not complete enough to serve as a reliable basis for selection of a heat source. Although it may have been possible to obtain sufficient data on infrared transmission and absorption to enable one to select the best heat source, a more direct procedure was used. This consisted simply of exposing the crude rock salt to each of several types of radiant-heat source on the small continuous separation device. The heat sources investigated, approximate source temperature used, and calculated wave length of maximum radiation are tabulated in Table I. Of the two types of tungsten-filament lamps investigated, both the short wave length photoflood lamps and the longer wave length infrared lamps were satisfactory from the standpoint of selectivity

Jan 1, 1961

By Frederic Benard

PRIoR to 1936, the Ontario Refining Co. received all incoming blister copper from The International Nickel Company&apos;s smelter in the usual form of 460-lb. cakes, or slabs. These were received in open cars in lots of 250 pieces. At the refinery the cakes were unloaded onto narrow- • gauge cars, for convenient handling and pickup by charging cranes. In March 1936, an investigation was started on the feasibility of transferring converter copper in the molten state from the smelter to the refinery anode furnaces, a distance of 1 1/4 miles. Although common in steel practice, the transportation of blister copper in this form had not previoisly been attempted and a preliminary study of the various factors involved was therefore necessary. For this purpose, a series of experiments was made in which molten copper, removed at different stages during the furnace cycle, was held in a small portable holding furnace. This vessel was essentially a refractory-lined steel cylinder provided with ports for filling and emptying, heated by an oil burner. Dimensions of the steel shell were 3 ft. 10 in. diameter by 7 ft. 3 in. long, and thickness of refractories depended on the design and combination used for the particular experiment. The vessel was filled with approximately 2 1/2 tons of copper at a predetermined temperature, the lining having been preheated to a definite point by means of an oil burner. All openings were well luted and temperature readings were made every 15 min. by means of an immersion-type thermocouple. In this manner the rate of heat loss resulting with different refractory design could be developed. The ratio of exterior surface to weight of metal was taken into consideration in comparing the experimental results with what might be expected for a full-sized unit, and observations were also made on type and degree of slag accretion. It was not possible to get as much information on this latter point as desirable, but all evidence showed that the problem would be control of slag build-up rather than attack on refractories. From the information derived, and in consultation with the engineering staff of the supplying company, an order was placed for the first

Jan 1, 1944

By Philip D. Anderson, Ralph Hultgren

Heat contents of extremely pure iron were measured over the range 300"to 1433"K, using a diphenyl ether calorimeter. Results from three samples containing widely differing impurities agreed with one another and with Previously reported results at higher temperatures (1184 ° to 1809°K) by Olette and Ferrier. From these data a table of heat contents of iron has been Prepared which is believed to be more accurate than those previously available. CP values have been derived which are consistent with these heat contents, with the best experimental Cp data, and with the thermodynamic conditions of equilibrium between bcc and fcc iron. The opinion is expressed that low-temperature extrapolations of presently known Cp values for y-Fe are not reliable. It would seem that the thermodynamic properties of iron, which is by far our most important metal, should have been well established long ago. This is not the case, however. As discussed by Olette and Ferrier,&apos; there is objection to every earlier heat content measurement. While the best true Cp determinations agree well at temperatures below the Curie point, there is wide divergence at higher temperatures. Several investigators have examined available data and attempted to calculate thermodynamic functions for iron that are consistent with the two equilibrium temperatures of bcc and fcc iron. The two primary efforts were those of Austin&apos; in 1930 and Darken and smith3 in 1948. The recommended values differ considerably; integration of Austin&apos;s Cp values leads to a heat content at 1100°K which is 300 cal per g-atom higher than the value recommended by Darken and Smith. The compilation of Fisher4 in 1949 was based on the selection of Austin. In 1956, Weiss and Tauer obtained yet another set of values by resolving Cp values into components due to dilation, lattice vibration, electronic excitation, and magnetism. The magnitude of contribution by each component and its dependence on temperature was estimated by semiempirical means. Their values are not self-consistent in that they do not form smooth curves when plotted vs temperature; moreover, their calculations cannot easily be repeated since they do not give the values of some of the parameters used. Clearly, experimental values for iron were in a most unsatisfactory state. The presently described measurements of the heat content of iron were therefore undertaken, covering temperatures as high as 1433°K. While the work was in progress, the high-temperature (1193" to 1789"K) heat content measurements of Olette and Ferrier&apos; were published; in the region of temperature overlap the present results agree with Olette and Ferrier well within experimental accuracy. It is believed that the present results, combined with those of Olette and Ferrier, provide for the first time a reliable set of heat contents of iron from room temperature to the melting point. From these data, guided by available Cp measurements, it proved possible to derive Cp, entropy, and free energy function values for @-iron from room temperature to the melting point, and for y- iron in the temperature region of its stability. Exhaustive study led to the conclusion that extrapolations of y-iron functions to room temperature were not reliable enough to be useful; hence these have been omitted from the tables. EXPERIMENTAL Materials. Three samples of extremely high purity iron from different sources, containing widely different impurities, were measured. The first of these, designated "Chipman", was kindly supplied by Dr. K. K. Kelley of the U. S. Bureau of Mines from a lot which was made many years ago by Dr. John Chipman of the Massachusetts Institute of Technology. The second, designated6&apos;Teddington", was supplied by the National Physical Laboratory, Teddington, England, from a lot zone-refined by them. The third sample, designated "Irsid", was supplied by the Institute de Recherches de la

Jan 1, 1962

By D. A. Farmen

INTRODUCTION In early 1978, engineering personnel at The Carter Mining Company began using photogrammetry coupled with a computer modeling technique to aid in mine planning efforts. The decision to develop this approach was based on the following needs: 1. A method to accurately capture excavated quantities for reporting purposes, 2. A method to produce accurate up-to-date maps for planning purposes, and 3. A computer-based mine-planning technique that would be compatible with techniques used in the past. The system developed utilizes a photogrammetric contractor to provide thousands of aerially-surveyed data points for input into the computer system. Each month the Rawhide and Caballo mines are flown by the photogrammetric contractor. The terrain of the active pit area is digitized and punched out on computer cards. This information is read into The Carter Mining Company&apos;s computer facilities, and an updated two-dimensional topographic grid model of the pit is generated. This surface is used to generate quantities moved during the month, to update isopachs, and to update quantities contained in fixed block progression polygons used for forecasting purposes. The system has greatly reduced the amount of manhours spent in field surveying and provides a useful tool for expeditiously evaluating many different forecast cases. It also provides the

Jan 1, 1983

By Fred Beasley

METALLURGISTS have, in the past ten years, overcome many difficulties of high zinc in lead blast-furnace slags. This problem was brought to the front at the close of the late war, by the price obtained for lead and the high cost of labor, fuel, and flux. The Port Pirie plant of the Broken Hill Associated Smelters, Australia, early in 1919 had increased the zinc oxide in its blast-furnace slags from 13.5 to 20 per cent., at the same time reducing the iron oxide in the slag from 33.5 to 25.6 per cent. These results were obtained by the following proceduret the addition of granulated slag to the roaster charge, 10 to 12 per cent., improved conditions of the crushing and mixing and roasting of the constituents of the sinter. By experiments and improve-ments the practice at this plant has developed a normal slag that carries 22 per cent. zinc oxide, and at times runs as high as 33 per cent. zinc oxide, with only slight furnace trouble. The granulated slag is used not, only as a diluent to the sulfur in the roaster charge, but also on account of its value as a slag-forming material and on account of the physical properties it imparts to the finished sinter. The ore is mixed with flux and given a double roast. All the first roasting is by sintering with the Dwight & Lloyd machines. The final roasting is performed partly by Dwight & Lloyd machines and partly by H. & H. pots. The charge to the blast furnaces consists chiefly of the final sinter, slag shells, siliceous and non-bearing sulfur, lead ores. High blast and ore columns are the practice. The greatest care is taken to obtain in the final sinter as low a sulfur content as possible.

Jan 2, 1925

By M. P. Nackowski

Geological engineering expanded its role and significance during 1966 in the areas of construction, raw materials exploration and inventory, water supply and pollution, mechanical properties of earth material and regional environmental planning. Efforts varied immensely in scope and magnitude, in simplicity, difficulty and importance. Observations, measurements, and analysis encompassed both simple and sophisticated procedures. CONSTRUCTION Activities in construction ranged from preliminary to detailed evaluations of sites, development of preventative measures and designing corrective measures following construction failures. Most investigations concerned dam sites, highway locations and slope stability, building sites, tunnels and underground storage facilities.

Jan 2, 1967

By L. L. McDaniel

ROLLER—As one who has been privileged to read Mr. Poland&apos;s paper before its publication, I wish to express high praise for it and the record which it gives of the work done by the Research and Development Department of Revere Copper and Brass Inc. in developing a satisfactory furnace for the recovery of metallic zinc from secondary metals by distillation. I have also had the opportunity of studying the operation of the furnace when running on scrap brass at the Detroit plant of Revere, and I can therefore say from knowledge gained first-hand that the unit is efficient and economical when used in conjunction with distillation. However, when I read what Mr. Poland has to say in reference to the possibility of using the furnace for melting copper cathodes for the production of oxygen-free and tough-pitch copper shapes, I am constrained to be somewhat skeptical. No doubt the furnace can readily be modified so as to make it possible to melt cathodes, but that is only a part of what is required to produce refinery shapes. Because of its construction the atmosphere in the furnace is highly reducing and even without protective gases such as nitrogen the copper cathodes which are

Jan 1, 1950

By F. F. Poland

S. ROLLE*—As one who has been privileged to read Mr. Poland&apos;s paper before its publication, I wish to express high praise for it and the record which it gives of the work done by the Research and Development Department of Revere Copper and Brass Inc. in developing a satisfactory furnace for the recovery of metallic zinc from secondary metals by distillation. I have also had the opportunity of studying the operation of the furnace when running on scrap brass at the Detroit plant of Revere, and I can therefore say from knowledge gained first-hand that the unit is efficient and economical when used in conjunction with distillation. However, when I read what Mr. Poland has to say in reference to the possibility of using the furnace for melting copper cathodes for the production of oxygen-free and tough-pitch copper shapes, I am constrained to be somewhat skeptical. No doubt the furnace can readily be modified so as to make it possible to melt cathodes, but that is only a part of what is required to produce refinery shapes. Because of its construction the atmosphere in the furnace is highly reducing and even without protective gases such as nitrogen the copper cathodes which are

Jan 1, 1950

By J. Price Wetherill

The coal-seams that are worked vary from 3 1/2 to 100 feet in thickness, and occur at all angles of inclination, but are never flat for any great extent. They contain coal, slate, and an unsolidified coal, called dirt by the miners, in various proportions, a uniform seam of coal alone being rare. The upper walls are composed of conglomerate, sandstone, or slate; the first two hard and solid in texture, and withstanding the action of the atmosphere and moisture sufficiently well to offer but little trouble to the mining operations; while the latter crumbles rapidly, owing, in part, to the decomposition of iron pyrites which it contains in large quantities, and in part to its own friable character, and requires constant care to avoid accidents to the men working below it, and to prevent its mixing with the coal mined. The floors are composed of slate. As in all mining operations, the general system pursued is to reach with a permanent outlet such a point in the seam as will

By D. H. Polonis, M. B. Kasen

AN unusual thermal etching phenomenon has been observed on the surface of a Cu-Si alloy. The observations were made during studies of vacancy condensation pit formation which were reported in previous papers.1,2 Figs. 1 and 2 are photomicrographs of the surface of a Cu-4.8 pct Si alloy after heating in vacuo (3 x X mm Hg) to 525°C and subsequently holding at that temperature for 16 hr in an impure (air-contaminated) argon atmosphere. Under these conditions preferential removal of silicon from the matrix by oxidation results in a surface which is entirely a phase overlying an a plus y structure. The light areas of Fig. 1 are regions in which very little thermal etching has occurred, while the majority of the surface has experienced severe etching. Similar regions in Fig. 2 are seen as plateaus above contours produced by net transfer of material from the specimen surface. Twin boundaries are also visible in Fig. 2. The difference in matrix mi-crostructure between Figs. l and 2 reflects the par- ticular orientation of low-index planes with respect to the surface of observation. Thermal etching contours of this type have been studied in detail by Hondros and Moore Both of the photomicrographs show that one or more dark spots are located approximately at the center of every protected area; where two spots are in close proximity, the protected areas have merged. The microstructures indicate that the anomalous resistance to thermal etching is related to the presence of these spots. Williams and Hayfield have shown that local regions of unusually high oxidation resistance can be caused by a surface monolayer of atoms with a work function higher than that of the base material. The result is an inhibition of the rate of electron removal from the base material and a decrease in the oxidation rate. The source of the protected layer may be either surface diffusion from contaminants on the specimen surface or pipe diffusion of solute atoms followed by migration across the surface. In the latter case the driving force is a difference in chemical potential resulting in a Gibbs adsorption phenomenon. In the present case, chemical polishing of the specimen surface precluded contaminants of a strictly surface nature. Consequently, diffusion of impurity atoms from within the lattice appears to be the most tenable explanation of the observed phenomena. The authors propose that the structures of Figs. 1 and 2 reflect the diffusion of impurity atoms along extended dislocations within the individual a phase grains prior to surface oxidation. The central spots within the protected regions are seen as sites of dislocation emergence which have become locally decorated with oxide in the manner discussed in Ref. 1. Williams and Hayfield observed protected regions adjacent to the grain boundaries of iron-contaminated copper which they attributed to the segregation of iron to the grain boundaries coupled with high dif-fusivity along the complex dislocation array at such boundaries. No evidence of such grain boundary protection was observed in the Cu-Si alloy; this

Jan 1, 1964

THE Institute assembled on Tuesday evening, October 24th, in the hall of the Franklin Institute, Mr. Frank Firmstone, Vice-President, in the chair. Mr.. J. Price Wetherill, of Tremont, Pa., read a paper on An Outline of Anthracite Coal Mining in Schuylkill County, Pa. The paper was discussed by Messrs. Coxe, Rothwell, Heinrich, Harden, and Symons. The second session was held on Thursday evening. Mr. A. L. Holley, Chairman of the International Committee, appointed by the Institute to consider the nomenclature of iron and steel, offered the following report of the committee, signed by all the members: WHEREAS, The recent production of soft, cast, malleable compounds of iron by the Bessemer, the Siemens-Martin, and the crucible steel processes appears to demand a new nomenclature of iron compounds, for the following reasons : 1st. The term "steel," by which these soft products are commercially and professionally designated in England and in the United States, does not completely distinguish them from previously existing "steel" which would harden and temper. 2d. A nomenclature recognized in all languages seems desirable, as well for commercial as for scientific purposes, especially as lawsuits, already commenced, depend on the meaning of the term "steel." 3d. Although homogeneity, due to fusion, is usually recognized, and is by this committee recognized as the most definite characteristic of both bard and soft steel, this quality may be equally well expressed in other terms, thus leaving the old term, "steel," to define the malleable compounds of iron, which will harden and temper. Therefore, resolved, That this committee recommends the following nomenclature : 1. That all malleable compounds of iron with its ordinary ingredients, which are aggregated from pasty masses, or from piles, or from any forms of iron not in a fluid state, and which will not sensibly harden and temper, and which generally resemble what is called " wrought iron," shall be called WELD IRON (German, Sehweisseisen; French, fer soudé) 2. That such compounds, when they will from any cause harden and temper, and which resemble what is now called "puddled steel," shall be called WELD STEEL (German, Schweiss stahl; French, acier soudé).

Jan 1, 1877