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By Edward B. Durham

At the Richmond mecting in February, 1901, I presented for discussion the proposed rail-specifications of Committee No. 1 of the American Section of the International Association for Testing Materials, with a review of their work, and other matters relating to the heat-treatment and chemical composition of steel (Trans., xxxi., 455). In order to bring out the views of our members on the important points referred to, I offered for discussion the following questions and comments (trans., xxxi., 972): " 1. The advantages to be gained by using more metal in the flanges and web of the heavier sections of rails.

Jan 1, 1903

By AIME AIME

AT a joint meeting of the Tulsa Geological Society and the Mid-Continent Section of the A; I. M. E., held at Tulsa on March 21, the history of unit development in the Kettle- man Hills field was discussed. Robert C. Patterson? Super- visor for the U. S. Geological Survey at Taft, Calif., was the speaker. An abstract of some of his remarks follows: On July 1, 1923, curtailment agreement for two years was made between the operators of North Dome Kettleman and the U. S. Department of the Interior. In this it was agreed to consider a plan of unit development, or other cooperate method of developing the structure. As a result, Kettleman North Dome Association was incorporated in December, 1930, as a non-profit cooperative corporation under the laws of California. Approved in January, 1931, by California Oil and Gas Supervisor and by Secretary of Interior. On Feb. 10, 1931, it became an active organization through election of executive officers and eleven- directors. General manager chosen. Association started to function April 1, 1931. Assumed control of 10,800 acres of proved and semi-proved land, as shown in Table 1.

Jan 1, 1932

By T. M. Chance

THE first bituminous coal cleaning-plant to use the sand-flotation process1 was placed in operation on Oct. 1, 1925, at the tipple of the East Broad Top Railroad & Coal Co., at Mt. Union, Pa. The general principles governing the design of plants of this type and typical operating results of anthracite sand-flotation units have been previously outlined.2 I will, therefore, confine myself to a description of this particular plant and to some of the elements of design it incorporates. THE ORIGINAL MT. UNION TIPPLE The plant was installed to transfer coal from steel narrow-gage cars of 60,000 and 70,000 lbs. capacity to standard-gage equipment. The coal was hauled some 30 miles from the East Broad Top field. This coal, mined by the Rockhill Coal & Iron Co. and other operators, is a low-volatile slow-coking coal with- ash of high-fusion point. It is normally a high-grade coal that does not contain an excessive amount of free impurities, but it requires careful handling to secure a fair domestic yield, and, naturally, the need for narrow-gage transshipment increases the difficulty of the problem. The narrow-gage cars were discharged into an 8-car track hopper equipped with two feeders passing the coal to two 42-in. apron intake conveyors. Twin units were installed throughout in this original plant, two lump-and-egg shaking screens, two lump picking-tables, two egg picking-tables and two stoker conveyors. The stoker coal was loaded without cleaning. The loading tracks and booms were in duplicate and with the layout as originally installed either unit could be run independently, each unit shipping a different class of coal or both units making the same product.

Jan 2, 1926

By Jacques Steininger, Robert E. England

Single crystals of ZnTe and ZnTe1-,Sex with x up to 0.13 have been grown from the elements by temperature gradient solution zoning using excess tellurium as a solvent. Best results have been obtained with charges with the compositions 45/55 at. pct Zn, Te, for ZnTe and increasing amounts of selenium for ZnTe1-xSex. The temperature in the molten zone was maintained at about 1070°C with a gradient of about 10°C per cm. Chemical analyses of quenched ZnTe ingots show tellurium concentrations in the molten zone as high as 70 pct with concentration differences across the zone of 1 to 2 at. pct Dark dots which are observed by transmitted light microscopy in as-grown crystals can be removed by annealing in zinc vapor at 900 C. INTEREST in wide band gap semiconductors has led to a new study of ZnTe and ZnTel-xSex crystal growth. ZnTe is the only II-VI compound with a wide band gap (2.3 ev) that can be made p type with low resistivity. Attempts to make it n type with low enough resistivity to be useful for p-n junctions have so far been unsuccessful.1 ZnSe has a band gap of 2.65 ev but can be made n type only. However, ZnTel-xSex solid solutions with x as low as 0.36 have been made both highly n and p type2 with a minimum band gap around 2.12 ev3 at room temperature and appear to hold the best promise for efficient injection electroluminescence in the visible. ZnTe has the lowest melting point of the zinc chal-cogenides (1295°C) and consequently attempts have been made to grow crystals from both the liquid and the vapor phase.4 Complicated apparatus is required for growth from stoichiometric melts because of the high vapor pressures of the elements at the melting point of ZnTe and because of the problem of quartz devitrification. Small crystals have thus been grown in high-pressure equipment by Fischer5 and by Narita et a1.6 with pressures of the order of 50 atm of argon to prevent excessive evaporation from the melt. Large crystals of ZnTe can be obtained by growth from the vapor phase4 but they often present numerous dislocations and inclusions. An improvement in the quality of vapor- grown ZnTe crystals was reported by Albers and Aten7 by equilibration of mixtures of small crystals with compositions lying on either side of the solid single-phase field at fixed temperature. The same technique was later applied by Aten8 to the growth of ZnTe1-xSex crystals with less than 1 pct inhomo-geneity. Because of the higher liquidus temperatures of the solid solutions and the high vapor pressure of selenium, previous attempts to grow ZnTel-xSex from the melt have been limited and unsuccessful.9 The phase diagram of the Zn- Te system is reproduced in Fig. 1, based on data from Kobayashi10 and Kulwicki.11 Carides and Fishher12 have reported lower liquidus temperatures on the tellurium-rich side, but their data would require confirmation. The liquidus temperature on the tellurium-rich side decreases rapidly with increasing tellurium concentration and the Te2 vapor pressure over the liquidus also decreases accordingly.'3 The decrease in liquidus temperature and vapor pressure therefore makes it possible to use conventional apparatus if there is a sufficient excess of tellurium in the melt. Single crystals of ZnTe have thus been grown by Kucza,14 in a modified Bridgman technique, from solutions containing up to 60 at. pct of Te by lowering unsupported quartz ampoules through a temperature gradient at about 1200°C. Under these conditions, the phase diagram indicates that the entire charge is initially molten. Crystal growth can therefore proceed by normal freezing and rejection of excess tellurium into the melt. The modified Bridgman technique has several major limitations. Because of the rejection of excess tellurium into the melt during freezing, the melt composition and the temperature at the growth interface vary continuously. They tend to follow the liquidus until the eutectic which is very close to pure tellurium (447°C, >99 pct Te). Since the solidus composition also varies with temperature,15 crystals grown by this method are inhomogeneous. They present small variations from stoichiometry which may affect their structure and physical properties. The simultaneous increase in tellurium content and decrease in melt temperature also combine to reduce the rate of diffusion of tellurium away from the growth interface, thereby causing constitutional supercooling and possibly dendritic growth. To minimize these effects, the initial melt composition is in practice kept relatively close to stoichiometry (less than 60 pct Te). This however limits the possibilities of operating at low temperatures and pressures. This paper describes a modified method of crystal growth by temperature gradient solution zoning (TGSZ) which is an adaptation of the temperature gradient zone-melting technique developed by pfann16 and of the traveling solvent method of Mlavsky and weinstein.I7 The TGSZ method now applied to the growth of ZnTe and ZnTel-xSex crystals is characterized by its very simple experimental arrangement and sample preparation technique. Unlike the modified Bridgman technique, there is no increase in the tellurium concentration in the melt and therefore it is possible to operate at lower temperatures and pressures. This method is also suitable for maintaining a constant temperature at the growth interface.

Jan 1, 1969

By W. A. West

ONE who attempts to collect and classify equilibrium data from various iron-alloy systems is soon struck with the absence of any quantitative theory that can serve as a general background against which to compare and contrast results from different systems, at different temperatures, and with different concentrations. It is not necessary to wait for a perfect theory; investigation of divergences of theory from observation may prove of great value in acquiring understanding of the subject. For example, one has only to think of Raoult's law as applied to aqueous solutions. The equations developed by Zener1 represent an effort to provide such a quantitative theoretical background, and it is therefore desirable to subject this theory to such tests as can be applied. The present article is intended to be an application of available tests, and may thus be considered as a supplement to Zener's paper. It is assumed that this paper is available to the reader. The equations make it possible to calculate the effect on the equilibrium concentration of one alloying element due to the presence of one or more other elements. In particular they are intended to give, for alloy steels, the carbon concentrations in alpha and gamma phases in equilibrium with each other, and in gamma in equilibrium with cementite. They may, however, be modified for use for carbon-free alloys. A summary is given later of the equations used in analyzing the data in this paper, and the symbols are there defined. About 125 papers have been examined for experimental data suitable for this investigation. An effort was made to look up all available reports of ternary systems including iron and carbon, as well as similar systems of higher order. Supplementary material was also obtained from a number of binary systems. A few noncarbon ternary systems were also found to which these methods could be applied. A comparatively small proportion of the papers read provided usable material. In many systems the number of quantitative observations made in the iron-rich region is extremely small, and the smoothed curves to be found in most published phase diagrams are entirely useless for quantitative treatment. This opinion is confirmed by the authors of the series on Alloys of Iron Research, whose remarks show clearly that they have no illusions as to the accuracy of many diagrams that they present. A further difficulty arises from the fact that these equations apply only to rather low percentages of alloying elements. The result is that at the lowest concentrations, where the best agreement might be hoped for, the errors of observation become relatively very large. The experimental difficulties in measurements of this kind of equilibrium are, of course, an old story.

Jan 1, 1946

By W. J. Sharwood

The assay or estimation of the total gold content of an ore presents little difficulty, when circumstances permit of securing a thoroughly representative sample. The general practice has been fairly standardized, and such errors as occur in the results obtained are for the most part attributable to the methods of sampling rather than to those of assaying, while duplicate assays made by skilled workers usually agree closely. When it is a question of estimating the "free" or amalgamable gold of an ore, as opposed to the total gold, there is but little uniformity in the methods employed by different workers, and often equally little in the results obtained when duplicate determinations are attempted, no satisfactory standard method having been generally adopted. The methods in use are of two general types—"panning" and "amalgamation." Panning For the estimation of the value of the visible gold by panning or washing, a weighed sample may be taken, ranging from an ounce to several pounds; a kilogram or 2 lb. is a favorite quantity for laboratory tests, while a prospector often uses a full miners' pan, say nearly 20 lb. or 10 kg. In the case of rich quartz, ground to about 30 or 40 mesh, a Mexican horn is convenient, using 1 to 8 02;. of material, and a 6-in. frying pan is favored by many prospectors in dry districts. Bateas, plaques, and dishes of various patterns are used for the same purpose. With these, fairly close results may be obtained by using for ocular comparison standards consisting of weighed amounts of gold of similar character as regards purity, fineness of division, and the general shape of the particles, which standards are preferably obtained from gold of the same locality, or the same deposit, as the ore or gravel being tested. Men working in one particular district sometimes become surprisingly expert in thus judging the value of an ore by the eye, the weights of both ore and gold being guessed. On the other hand, many have been led to overestimate the value of ore and gravel from unfamiliar localities, where the gold has been very finely divided or of unusually high silver content, and a novice may

Jan 1, 1916

By R. T. Torgerson, W. A. Baginski

Alloying studies were conducted on modifications of Cb-10W-1OHf (C-129) alloy as part of a cooperative alloy development effort between The Boeing Co. and the Wah Chang Corp. The purpose of these studies was to develop a fabricable, high- strength columbium alloy with superior melding properties. The initial investigations of alloy modifications were conducted using laboratory-melted button ingots. An alloy with the composition exhibited excellent veld ductility, elevated-ternpevature strength, and fabricability. The yttrium-modified alloy was desigrzated C-129Y and was selected for further developrnetzt. Three prodziction heats of C-129Y weve processed into sheet. Welding, forming, and tensile proper-lies are presented for this material. Tungsten-are welds of. C-129Y exhibited a minimum bend radius of 1/2T in the as-welded conditioti compared to 8T for C-129 alloy. An investigation was conducted on Disil coating of C-129Y and test data are presented on oxidation resistance and effects of re-entry environments. The excellent combination of strength, fabricability, weldability, and low transition temperature of C-129Y alloy offers potential design advantages for use of this alloy in structures of aerospace vehicles. It is atiticipated that C-129Y will rapidly supplant C-129 and similar alloys clue to the versatility provided by its impvoved welditzg properties. COLUMBIUM alloys with improved properties are required to achieve better performance and efficiency of radiation-cooled structures for re-entry vehicles and recoverable launch systems. Cooperative work by The Boeing Co. and the Wah Chang Corp. resulted in the development several years ago of C-129 alloy, a high-strength Cb-W-Hf alloy.' This alloy has received favorable consideration for many advanced designs of high-temperature structures due to its excellent combination of properties. However, this alloy exhibits low weld ductility unless given a high-temperature stress-relief treatment. For this reason the development effort was directed towards modification of the C-129 alloy composition (Cb-1OW-1OHf) to eliminate the need for post-weld heat treatment. This paper describes the successful development of an alloy meeting this requirement. This new alloy was designated C-129Y and has a nominal composition of EXPERIMENTAL PROCEDURES Alloying Studies. Various Cb-W-Hf compositions were investigated using are-melted button ingots. These buttons were hot-forged using a protective glass coating and rolled into sheet specimens. Metal-lographic examination: tensile testing, and welding studies were conducted to evaluate properties of the experimental alloys. Sheet Fabrication. Three pilot production heats of C-129Y were fabricated into sheet to establish processing techniques and to determine sheet properties. The three heats consisted of 6-in.-diam ingots weighing from 140 to 250 lb. The ingots were prepared by electron-be am melting followed by vacuum-arc melting. The hafnium and yttrium additions were made during the are-melting operation by tack welding alloy strip additions to the Cb-W master-alloy electrode. The final ingots were machined into billets with samples of the machine turnings collected for chemical analysis. Ingot breakdown methods for the three heats are as follows: Ingot Ingot Heat Size Weiaht___Breakdown Method A 6 in. 250 lb Hot extrusion B 6 in. 140 lb Hot forging C 6 in. 250 lb Hot extrusion Sheet bars from the extrusion and forging operations were conditioned, recrystallized, and rolled into sheet. Initial rolling was conducted at elevated temperatures and final rolling was conducted at room temperature.

Jan 1, 1967

By V. V. J. Sarma

Interpretation of earth resistivity data involves not only obtaining depth to interfaces but also determining the nature of formations from their resistivity characteristics. Moore's method of interpretation envisages obtaining depths to the interfaces alone. A simple method of estimating the true resistivity values of formations by applying Hummel's formula of average resistivities is proposed. The method would increase the interpretative value of Moore's method as originally proposed. For most of the earth resistivity measurements, the four-electrode configuration developed by Wennerl is employed. In principal, the method consists of energizing (Current I) the ground through two outer electrodes and measuring the resultant potential (v) between the two inner electrodes. The configuration is such that the separation (a) between any two successive electrodes is equal. The apparent resistivity (pa) for such a configuration is given by 2p- a (V/I). By increasing the electrode separation (pa vs a) curves are obtained. Ideally, a homogeneous isotropic formation underground has a characteristic resistivity. However, the field conditions do not present such ideal cases. Almost invariably, even in the same geological bed, the physical conditions are widely different at different parts in the bed. It is further shown that the penetration of the current into the ground for a given horizontal electrode separation, a, is roughly down to a depth, equal to a. It is therefore, evident that the apparent resistivity calculated from the field observations is a weighted average of the resistivities of the materials present down to this depth. With some prior knowledge about the relative dispositions of the geological formations and their physical conditions, it would be possible, by resistivity surveys, to obtain characteristic resistivities for these formations. It is, thus, that the apparent resistivity-electrode separation curves enable one to decipher the resis- tivity distribution at various depth levels and therefore the nature of the geological formations present. Both empirical and theoretical methods have been developed for determining resistivity characteristics of the various formations. The theoretical methods proposed by Tagg2 and Roman3 are derived from studies of the potential distribution on the surface due to the presence of layers of widely differing resistivities underground. The more recent methods of Wetzel and McMurry4 and Wetzel and Mooney5 are but extensions of the original Roman method of superposition. These methods suffer from lack of similarity of the actual field conditions with those of assumed conditions in developing the theory. The empirical methods such as the one developed by Gish and rooneY6 depend purely on personal observation and local peculiarities, and are applicable only for those limited areas. Out of the empirical methods, moore's7 cumulative resistivity method is still found to be applicable in several localities of differing conditions. While Reudy in 1945 adduced some theoretical justification for the method (Eve and Keys),8 Muskat9 and Mooney 10 tried to show the lack of theoretical basis for the same. It is, however, observed that the method in practice "forms a valuable means of successfully attacking the apparent resistivity curves which fail to respond to the Gish-Rooney, the Tagg or the Roman logarithmic methods" (Ramachandra Rao). 11 Comparatively good results are also reported by Melbyel2 by employing Moore's method in interpreting the resistivity results obtained for ground water in the city of Gunnison, Colo. MOORE'S METHOD As has already been pointed out, the application of the theoretical methods is time-consuming, laborious and sometimes not applicable for quick and accurate interpretation of the field data. moore7 has developed a quick method for obtaining depths to interfaces by plotting the cumulative sums of resistivities, against the corresponding electrode separations a instead of plotting the usual Pa — a curve. In this process of continuous integration, corrections for small variations in resistivities, arising due to local surface conditions or adjacent layers, are made, while large consistent variations are brought out

Jan 1, 1963

By A. A. Jr. Smith, J. S. Smart

Numerous investigations of the effects of the various impurities common to commercial coppers have been published, and the data have found wide use in industry. Naturally, emphasis has been placed on the oxygen-bearing coppers of the tough-pitch variety, but need is now evident for data covering the oxygen-free condition as well. Furthermore, relatively few of the important reactions between oxygen and the various impurities are well understood, and often the data at hand are not applicable to the low concentrations encountered in commercial coppers. This paper presents the changes in conductivity and softening temperature derived from individual additions of the group VIII triad, iron, cobalt and nickel, to high-purity copper, and constitutes a portion of the copper-research program being conducted at the Central Research Laboratory of the American Smelting and Refining Co. The method of preparation of high-purity copper and its alloys in either the oxygen-free or oxygen-bearing form has been described previous1y.l The purity of this material, and the methods developed to produce it, provide the means for direct investigation of the very low concentration range in which the various impurities generally exist in commercial coppers. The usual necessity for extrapolation to this range using the results obtained from higher concentrations, and the interfering effects of extraneous impurities, are thus simultaneously circumvented. Since previously published data have adequately presented the effects of higher concentrations of iron, cobalt and nickel, the present investigation has been confined to the composition range o to 0.05 per cent. All alloys were initially prepared in the form of oxygen-free continuous cast rod, the weighed alloying additions in suitable form being charged with the pure copper to the continuous casting crucible. The best of the available high-purity alloying materials were used, and spectrographic analyses confirmed the absence of interfering elements from the alloys formed. Each series was compounded in the direction of increasing concentration, starting with pure copper in a new crucible and finishing with the 0.05 per cent alloy. Composition was closely controlled by adding the alloying element in the form of a carefully compounded and analyzed master alloy rendered uniform by continuous casting. The accuracy of this method of synihesis was proved by chemical analysis of the more concentrated alloys, and, accordingly, there is every reason to credit the stated composition of the very dilute alloys in the range where chemical analysis becomes highly uncertain. Oxygen-free samples for measurements of conductivity and softening temperature Were obtained by drawing the continuous cast rod to wire of 0.08I-in. diameter. employing a number of intermediate anneals to refine the grain structure. The

Jan 1, 1942

By A. A. Smith, J. S. Smart

NUMEROUS investigations of the effects of the various impurities common to commercial coppers have been published, and the data have found wide use in industry. Naturally, emphasis has been placed on the oxygen-bearing coppers of the tough-pitch variety, but need is now evident for data covering the oxygen-free condition as well. Furthermore, relatively few of the important reactions between oxygen and the various impurities are well understood, and often the data at hand are not applicable to the low concentrations encountered in commercial coppers. This paper presents the changes in conductivity and softening temperature derived from individual additions of the group VIII triad, iron, cobalt and nickel, to high-purity copper, and constitutes a portion of the copper-research program being conducted at the Central Research Laboratory of the American Smelting and Refining Co. The method of preparation of high-purity copper and its alloys in either the oxygen-free or oxygen-bearing form has been described previously.1 The purity of this material, and the methods developed to produce it, provide the means for direct investigation of the very low concentration range in which the various impurities generally exist in commercial coppers. The usual necessity for extrapolation to this range using the results obtained from higher concentrations, and the interfering effects of extraneous impurities, are thus simultaneously circumvented. Since previously published data have adequately presented the effects of higher concentrations of iron, cobalt and nickel, the present investigation has been confined to the composition range 0 to 0.05 per cent. All alloys were initially prepared in the form of oxygen-free continuous cast rod, the weighed alloying additions in suitable form being charged with the pure copper to the continuous casting crucible. The best of the available high-purity alloying materials were used, and spectrographic analyses confirmed the absence of interfering elements from the alloys formed. Each series was compounded in the direction of increasing concentration, starting with pure copper in a new crucible and finishing with the 0.05 per cent alloy. Composition was closely controlled by adding the alloying element in the form of a carefully compounded and analyzed master alloy rendered uniform by continuous casting. The accuracy of this method of synthesis was proved by chemical analysis of the more concentrated alloys, and, accordingly, there is every reason to credit the stated composition of the very dilute alloys in the range where chemical analysis becomes highly uncertain. Oxygen-free samples for measurements of conductivity and softening temperature were obtained by drawing the continuous cast rod to wire of 0.081-in. diameter, employing a number of intermediate anneals to refine the grain structure. The

Jan 1, 1942

By A. A. Jr. Smith, J. S. Smart

Numerous investigations of the effects of the various impurities common to commercial coppers have been published, and the data have found wide use in industry. Naturally, emphasis has been placed on the oxygen-bearing coppers of the tough-pitch variety, but need is now evident for data covering the oxygen-free condition as well. Furthermore, relatively few of the important reactions between oxygen and the various impurities are well understood, and often the data at hand are not applicable to the low concentrations encountered in commercial coppers. This paper presents the changes in conductivity and softening temperature derived from individual additions of the group VIII triad, iron, cobalt and nickel, to high-purity copper, and constitutes a portion of the copper-research program being conducted at the Central Research Laboratory of the American Smelting and Refining Co. The method of preparation of high-purity copper and its alloys in either the oxygen-free or oxygen-bearing form has been described previous1y.l The purity of this material, and the methods developed to produce it, provide the means for direct investigation of the very low concentration range in which the various impurities generally exist in commercial coppers. The usual necessity for extrapolation to this range using the results obtained from higher concentrations, and the interfering effects of extraneous impurities, are thus simultaneously circumvented. Since previously published data have adequately presented the effects of higher concentrations of iron, cobalt and nickel, the present investigation has been confined to the composition range o to 0.05 per cent. All alloys were initially prepared in the form of oxygen-free continuous cast rod, the weighed alloying additions in suitable form being charged with the pure copper to the continuous casting crucible. The best of the available high-purity alloying materials were used, and spectrographic analyses confirmed the absence of interfering elements from the alloys formed. Each series was compounded in the direction of increasing concentration, starting with pure copper in a new crucible and finishing with the 0.05 per cent alloy. Composition was closely controlled by adding the alloying element in the form of a carefully compounded and analyzed master alloy rendered uniform by continuous casting. The accuracy of this method of synihesis was proved by chemical analysis of the more concentrated alloys, and, accordingly, there is every reason to credit the stated composition of the very dilute alloys in the range where chemical analysis becomes highly uncertain. Oxygen-free samples for measurements of conductivity and softening temperature Were obtained by drawing the continuous cast rod to wire of 0.08I-in. diameter. employing a number of intermediate anneals to refine the grain structure. The

Jan 1, 1942

By Robert Pike

THE first authentic description of an iron bath for the deposition of iron is probably that of Bottger in 1846, who used a bath containing ferrous sulfate and ammonium chloride. In 1861, Kramer deposited iron from ferrous chloride solution. Electrolytic iron was produced in 1.869 by Bietz, who used it for making some magnetic tests. In the same year, Klein is said to have worked out his process. Jacobi1 in 1869 described the results obtained in electroplating with iron on copper for making dies and plates for bank notes, by Klein's process. A letter from Klein to Jacobi describes the bath more fully. It consisted of FeSO4 + (NH4)2S04. Lenz2 described ?some properties of electrolytically precipitated iron. He used Klein's bath, FeSO4 + MgSO4 + MgCO3, to neutralize and obtained fine-grained and hard iron. His conclusions were as follows: 1. Electrolytic iron and copper contain gases, notably hydrogen. 2. The volume of gas absorbed by iron varies within wide limits, but it is easy for iron to take up very considerable quantities of gas. 3. The absorption of gas is principally in the first formed layers of iron. 4. When iron is heated, gas begins to come off below 100°, principally hydrogen. 5. Heated to redness, reduced iron oxidizes in water, in part at least at the expense of the oxygen of the water, decomposing it and setting free hydrogen, which is partly or wholly absorbed. Siemens,3 in 1889, was the first to propose a general process embodying a step for leaching a sulfide mineral with ferric chloride or sulfate and a step for regenerating the leach and depositing iron on a cathode in a diaphragm cell. So far as is known, Siemens did not carry out his patent

Jan 1, 1930

By Thomas L. Kesler

The Cartersville mining district, 35 miles northwest of Atlanta, Ga, has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. However, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magnesian limestone. General Geology Geologic relations of the ore deposits of this district are more or less similar to those of many Appalachian districts. The lowermost Cambrian formation, heretofore called Weisnerl in this region, supposedly partly or. wholly equivalent to the Erwin and Hesse quartzites as recognized to the northeast, is overlain conformably by the Shady† formation, also of Lower. Cambrian age. In the Cartersville district, the sedimentary rocks of these formations were folded with increasing intensity eastward, and were recrystallized.

Jan 1, 1941

By Thomas L. Kesler

The Cartersville mining district, 35 miles northwest of Atlanta, Ga, has been of varying but continuous importance in the southern mineral industry during the past century. Noted chiefly for its production of brown iron ore, manganese oxide ores, barite, sienna, and magnesian limestone, the district and its environs have produced brick and tile clays, slate, gold, bauxite, and graphitic schist. Minor deposits of serpentine, sericite schist, copper ore, and red iron oxide have been prospected. The obvious deposits of brown iron ore, together with some associated specular hematite, were mined out years ago, although a little ore was left in the workings. Moderately steady production of sienna reached a peak about 1930, then declined rapidly. Manganese mining passed through a relatively active period from the World War to 1931, but has subsided to a small but rather constant output for the Birmingham market. However, the White Manganese Corporation has prepared for possible increased production by constructing a new washer capable of handling about 300 tons of ore per day. Principal activity in the district proper has centered for some years in the production of barite and magnesian limestone. General Geology Geologic relations of the ore deposits of this district are more or less similar to those of many Appalachian districts. The lowermost Cambrian formation, heretofore called Weisnerl in this region, supposedly partly or. wholly equivalent to the Erwin and Hesse quartzites as recognized to the northeast, is overlain conformably by the Shady† formation, also of Lower. Cambrian age. In the Cartersville district, the sedimentary rocks of these formations were folded with increasing intensity eastward, and were recrystallized.

Jan 1, 1941

By C. G. Goetzel

Until recently porous bronzes have found many applications for self-lubricating bearings in the automotive, electrical, household appliance and general machine industries. The bulk of an annual production of several million pounds of copper powder had gone into the manufacture of these articles, of which by now more than a billion are in service. However, the war has brought severe curtailment of these bearings because of the scarcity of the two main constituents, copper and tin. The development of substitute materials of equal or superior properties has led to a large-scale replacement by products made from iron powder. In spite of the diminished interest in powdered copper-tin alloys caused by this trend, it was believed worth while to investigate some mechanical properties of these materials as a reference base for substitutes. In addition, experiments using the hot-press method were incorporated to investigate possibilities of saving vital equipment or opening new fields of applications. It must be assumed that by this time the powder metallurgy process of making porous bronzes, a development that found its first industrial applications more than 10 years ago, is well known in engineering. The patent literature and bibliography is volu- minous, most publications referring to porous, self-lubricating bronzes, containing about 10 per cent tin and I to 5 per cent graphite, with porosities in the range of 25 to 35 per cent.l-7 The excellent antifriction properties of these bearings, caused by the uniform impregnation with oil, are dependent on the interconnection of the pores and the uniform distribution of the graphite inclusions. The sintering mechanism of porous bronze, with its structural changes during the transformation of the metal powder into the sintered bearing has been shown in colored photomicrographs by Hall.* Diffusion between copper and tin was found to begin within one minute, when tin-rich transitory phases were formed. After 25 min. a homogeneous matrix of alpha was reached for an alloy containing 9.5 per cent tin and 6 per cent graphite. Price, Williams and Garrand,9 studying certain metal powder combinations in which sintering is accompanied by the cementing action of a liquid phase, including a 90-10 bronze sintered at 925°C., have found that if the treatment is carried out within the liquidus and solidus temperature range of the system, a peculiar process of alternate solution and precipitation occurs. The particles of the major solid constituent are dissolved in the minor liquid phase, but thereafter are reprecipi-tated on certain nuclei, which develop into large grains, usually rounded.

Jan 1, 1945

By R. K. Ham, M. L. Wayman

TD-Nickel has been broken in tension and in fatigue at voom temperature. Rod specimens failed in tension by necking, with axial cracks attributed to voids elongated in the extrusion direction. Fatigue specimens failed in shear. Thin-film electron microscopy showed that the subgrain structure of TD-Nickel was very stable, and that particle-matrix detachment was very difficult, in tension and fatigue. TD-Nickel softened slightly during fatigue but had a high fatigue ratio (0.5at 10' cycles). Fractography suggested that Stage I fatigue crack propagation is greatly extended in TD-Nickel. Td-NICKEL* is a dispersion of 2 pct by volume of thoria (ThO2) in nickel, produced by powder-metallurgical methods including compaction, sintering, and extrusion. The spherical thoria particles, which may have a mean diameter of a few hundred angstroms, are dispersed with a mean planar spacing of a few thousand angstroms. By a combination of cold working and annealing, a subgrain or cell structure of dislocations intimately associated with the dispersion can be produced.' This gives the material useful tensile properties which are extremely resistant to exposure to high temperatures.'-= At the same time, the material shows considerable ductility.3'4 At the beginning of the present work, it was considered of great interest to investigate the mechanical stability of TD-Nickel under conditions of fatigue. On the one hand, materials which derive strength from a cold-worked structure are unstable in that they are susceptible to fatigue softening: in addition, the presence of discontinuities such as the particle-matrix interfaces might be expected to assist in the initiation and propagation of fatigue cracks, in that they may provide local concentrations of internal stress and sites for the initiation of voids." On the other hand, the substantial ductility of TD-Nickel suggests that if it obeys Coffin's relation8 (or the more refined form proposed by Manson9) it should have good fatigue resistance. The initial purpose of this investigation was to assess the importance of these factors. Also, relatively little fundamental work has been done on the mechanism of fatigue in dispersion-strengthened materials. Work on overaged A1-4 pct CU10-12 revealed a very large Bauschinger effect indicative of internal stresses at the particles, and very great fatigue hardening1' presumably due to the multiple slip stimulated by these internal stresses, followed by softening which was initially due to softening in the matrix, but later might have arisen from cracking at the particle-matrix interfaces. The study of overaged Al-4 pct Cu could not settle this latter point by the electron microscopy of thin films, since the dispersion is too coarse. A previous study of the fatigue of internally oxidized copper13 was complicated by inter granular failure, attributed to oxide particles at grain bouhdaries; internal oxidation of single crystals, however, improved their fatigue properties.'3 Investigations of SAP (sintered aluminum powder) are complicated by the complex particle shapes, and the possibility of continuous internal oxide films.14 It was hoped to avoid these difficulties with TD-Nickel, which had the further advantages that it was commercially available and suitable for study by the thin-film technique. 1) MATERIALS AND EXPERIMENTAL PROCEDURE TD-Nickel was purchased from the Driver-Harris Co. as 3/9-in.-diam rod which had been extruded, swaged, and "stress-relieved" (normally at 1010°C for 1 hr). Continuous-radius fatigue specimens with a minimum diameter of -0.1 in. were ground to shape and electropolished in 40 pct phosphoric, 35 pct sul-furic, 25 pct water at 25oC, with a stainless-steel cathode, at -6 v. Fatigue tests were carried out at room temperature with a Sonntag SF-1-U machine operating in push-pull at 1800 cycles per min, and in an Instron TT-C-L modified for reversed stressing at 26 cycles per min as described elsewhere.10 Round tensile specimens were ground with 0.85-in. gage lengths of 0.135 in, diam, electropolished, and tested in a Tinius Olsen hydraulic machine. The surfaces of fatigue specimens were examined with a Reichert metallograph. Discs for electron microscopy with a Siemens Elmiskop I were spark-cut 0.01 in. thick with a modified Servomet 11 employing a tool of moving molybdenum wire, cleaned in 50 pct acetic, 30 pct nitric, 10 pct phosphoric, and 10pctsul-furic at 85oC, and thinned by the window method in the electropolishing solution at -20°C and -6 v. Two-stage replicas (parlodion, then Pt-50 pct C self-shadowed at 40 deg) were taken from fatigue fracture surfaces for electron microscopy. Plane sections parallel to the specimen axis and containing the direction of fatigue crack propagation were polished, etched with Carapella's reagent, and examined optically. Transmission Laue X-ray photographs of as-received material electropolished to a point were used to determine preferred orientation. 2) RESULTS 2.1) The Structure of As-Received Material. Grains -1 µ diam and elongated 20 to 30 u in the direction of the rod axis were observed, With' elongated "intergran-ular" voids (-4 p diam and -90 µ long and identified as such using longitudinal and transverse sections and

Jan 1, 1968

By H. S. Martin

THE Phosphate Recovery Corporation operates three flotation plants, Nos. 1 and 2 concentrators about three miles northeast of Mulberry, Florida, and No. 3 plant at Wales, Tennessee. These plants represent the first commercial phosphate flotation operation and are also believed to be the largest nonmetallic flotation operation in the world at the pres-ent time. The details of this paper will be confined to plant No. 2, this being the newest and largest concentrator in Florida, and the flow sheet being practically the same as at plant No. 1. The No. 3 plant has been oper-ated but a short time and has been shut down since December, 1932, on account of the decrease in phosphate rock production. The phosphate washers usually are located centrally on a known deposit so that about two hundred acres of ground can be mined eco-nomically to each washer location. The washers are moved to new areas when the distance becomes too great for economical pumping. The flotation plants are built either adjacent to a washer, so that current debris may be utilized, or on the site of a former washer where there is sufficient accumulated debris available for mining, and the flotation plants must also be moved from time to time. Most of the water used in the Florida flotation plants is recovered after passing through a circulating system where most of the fine sus-pended matter is settled out, but some make-up water is obtained from deep wells near the plant. Power is obtained from the Tampa Electric Co. through the dis-tribution facilities of the International Agricultural Corporation. Flotation concentrate is hauled from the plant by trolley over the International Agricultural Corporation's trolley system, to the drying plant at Prairie, one mile northwest of Mulberry.

Jan 1, 1933

By W. P. Sykes

Seven years ago, Dr. S. L. Hoytl presented a masterful discussion of the hard metal carbides and cemented tungsten carbide. His lecture summarized most of the data then available in the field; many of the details relating to the production, properties and structure of cemented tungsten carbide had never been previously published, for, in fact, this information was only then being acquired. During the intervening years, the cemented carbides have assumed a place of real importance in the commercial field, with an ever widening variety of applications due to constant improvement in the control of production technique and the unremitting search for new compositions that might better the performance of the alloys in one or another type of service. The most recent summary of production methods, properties and guides for the successful application of the cemented carbides appears in the 1936 edition of the Metals Handbook. Of necessity, much detailed information relating to structures and physical properties is not included in such a summary, and it is with such details that the present discussion is concerned. Steps in Preparation While the past 25 years have contributed a valuable store of working knowledge in the field of powder metallurgy, many of the process controls are derived entirely from experience and are not as yet finally explained by a specific physical or chemical phenomenon. For most of the cemented carbides such difficulties are aggravated by our lack of knowledge not only of the complex alloy systems involved, but also by the possible changes in structure and even in composition which may accompany variations in temperature, heating time, and furnace atmospheres. The principal steps in the preparation of these cemented carbide alloys are fairly well known, but to supply a foundation for discussion these steps are briefly outlined as follows : 1. Formation of the metal carbide in the form of powder by heating a mixture of carbon and the metal powder or oxide for several

Jan 1, 1938

By W. P. Sykes

Seven years ago, Dr. S. L. Hoytl presented a masterful discussion of the hard metal carbides and cemented tungsten carbide. His lecture summarized most of the data then available in the field; many of the details relating to the production, properties and structure of cemented tungsten carbide had never been previously published, for, in fact, this information was only then being acquired. During the intervening years, the cemented carbides have assumed a place of real importance in the commercial field, with an ever widening variety of applications due to constant improvement in the control of production technique and the unremitting search for new compositions that might better the performance of the alloys in one or another type of service. The most recent summary of production methods, properties and guides for the successful application of the cemented carbides appears in the 1936 edition of the Metals Handbook. Of necessity, much detailed information relating to structures and physical properties is not included in such a summary, and it is with such details that the present discussion is concerned. Steps in Preparation While the past 25 years have contributed a valuable store of working knowledge in the field of powder metallurgy, many of the process controls are derived entirely from experience and are not as yet finally explained by a specific physical or chemical phenomenon. For most of the cemented carbides such difficulties are aggravated by our lack of knowledge not only of the complex alloy systems involved, but also by the possible changes in structure and even in composition which may accompany variations in temperature, heating time, and furnace atmospheres. The principal steps in the preparation of these cemented carbide alloys are fairly well known, but to supply a foundation for discussion these steps are briefly outlined as follows : 1. Formation of the metal carbide in the form of powder by heating a mixture of carbon and the metal powder or oxide for several

Jan 1, 1938

By Francis L. Bosqui

The following paper embodies a report which I made on the filter-press treatment of slimes at the Liberty Bell mine, Telluride, Colo. At the time this report was submitted, the management deemed it wiser to defer the installation of so costly a plant as the one required, in the hope that some of the many investigators in the field might soon evolve a cheaper and more perfect method of slimes-treatment, and one better suited to the conditions at Telluride. The Liberty Bell ore consists essentially of quartz and clay, with iron pyrites disseminated through the quartz in very fine particles. There is considerable iron and manganese stain in some of the ore, the latter especially in the clays, which are sometimes quite black. Occasionally particles of galena, zincblende, gray copper and a few other minerals are seen, but they are comparatively rare, and not in sufficient quantity to affect considerations of treatment. Free gold is occasionally seen in the quartz, and one or two instances of mire silver have been observed. The milling-plant consists of an 80-stamp amalgamating mill which crushes through 20-mesh screens; 20 Wilfley concentrating tables, taking out, in iron sulphides, about 2 per cent. of the total ore crushed; and a cyanide plant consisting of two tiers of 33 ft. vats, five in each tier, fed by revolving pipe-die tributers. The slimes overflow from the upper settling tanks through gates with adjustable outlets, and thence to a large canvas-plant, which efects only a small saving. This slimes product, of which about 100 tons escape per day (or 38 per cent. of the total ore crushed), contains about 3 per cent. of dry solids. Of this approximately 93 per cent. will pass a 200-mesh screen. The slimes range in value between $3.90 and $4.87 per ton, the values being about equally distributed between gold and silver. The actual averages for ore and slimes during the years 1900-

Jan 1, 1904