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By J. R. Long, R. S. Dean, F. S. Wartman, E. T. Hayes

The production of titanium in I5-lb. lots and with a purity sufficient to be consolidated into ductile metal, as described in a previous paper,' has provided adequate material for a study of the physical properties of titanium and a more thorough examination of its working qualities. Data on the physical properties reported in that paper were obtained on metal fabricated by a fixed procedure, standardized for the purpose of control of the reduction, and are representative only of material fabricated under those conditions. There are many possible variables in the working schedule, which will have significant effects on the properties of the finished material; and since the previous working methods were not necessarily the best, an investigation of the fabrication of titanium by other methods was undertaken. In this work the consolidation of the powder by pressing and sintering was conducted essentially as outlined in the report cited' and all efforts were centered on fabrication methods for those powders and the proper- ties produced by them. Hardness, density, microstructure, and tensile properties were determined at various stages in the working and annealing; and resistivity measurements were made on a few bars and drawn wire. Consolidation of the PowdeR The screen analysis of the available titanium powder is given in Table I. No attempt was made to alter the size distribution from that noted because this powder, although coarse by normal powder-metallurgy standards, produced acceptable compacts suitable for the present work. Because of their large specific surface, finer powders are more contaminated by oxygen and produce harder compacts, which are difficult to work. The powder as produced is soft, compresses in a normal fashion, and exhibits very little tendency to adhere to the die surfaces. Unlike aluminum and magnesium powders, it can be readily pressed without the use of die lubricants. When compacted at 50 tons per

Jan 1, 1946

By J. R. Long, E. T. Hayes, R. S. Dean, F. S. Wartman

The production of titanium in I5-lb. lots and with a purity sufficient to be consolidated into ductile metal, as described in a previous paper,' has provided adequate material for a study of the physical properties of titanium and a more thorough examination of its working qualities. Data on the physical properties reported in that paper were obtained on metal fabricated by a fixed procedure, standardized for the purpose of control of the reduction, and are representative only of material fabricated under those conditions. There are many possible variables in the working schedule, which will have significant effects on the properties of the finished material; and since the previous working methods were not necessarily the best, an investigation of the fabrication of titanium by other methods was undertaken. In this work the consolidation of the powder by pressing and sintering was conducted essentially as outlined in the report cited' and all efforts were centered on fabrication methods for those powders and the proper- ties produced by them. Hardness, density, microstructure, and tensile properties were determined at various stages in the working and annealing; and resistivity measurements were made on a few bars and drawn wire. Consolidation of the PowdeR The screen analysis of the available titanium powder is given in Table I. No attempt was made to alter the size distribution from that noted because this powder, although coarse by normal powder-metallurgy standards, produced acceptable compacts suitable for the present work. Because of their large specific surface, finer powders are more contaminated by oxygen and produce harder compacts, which are difficult to work. The powder as produced is soft, compresses in a normal fashion, and exhibits very little tendency to adhere to the die surfaces. Unlike aluminum and magnesium powders, it can be readily pressed without the use of die lubricants. When compacted at 50 tons per

Jan 1, 1946

By J. F. Elliott

PRESENT knowledge of the usual metallurgical slags indicates that they are, for the most part, rather complex in behavior and as yet there is no ready means for describing, in a simple manner, the behavior of any one of them. One of the best known slag systems is the iron oxide-silica-lime ternary which is the basic "solvent" in a number of important metallurgical refining operations, the basic open hearth being one of the most important. In this operation, the slag dissolves such components as sulphur, phosphorus, manganese oxide, and magnesia. Considerable study of this slag system and the behavior of these additions has been carried out in the past by a number of authors, as has been summarized in several critical reviews.','2 However, except for determination of the activity of iron oxide, only a limited amount of effort has been directed towards developing, from these data, an understanding of the general behavior of the basic solvent. Reported here are the results from a series of calculations based on data from the literature which permit a semiquantitative evaluation of the activities of iron oxide, silica, and lime (plus magnesia) in the ternary system at 1600°C. The preliminary results, which were reported briefly at a symposium held by AIME in 1953, have been revised and are completed. The steps in the calculation are as follows:* I—establish the activity curves and the curve of the excess molar free energy of mixing at 1600°C for each of the binary systems, 2—construct the activity surface of iron oxide for the ternary from the data on the binary systems and information available in the literature for the ternary area, 3—determine the surface of excess molar free energy of mixing for the ternary system from the activity surface of iron oxide and from the molar curves obtained for the binary system, and 4—differentiate the ternary surface of the molar excess free energy of mixing to obtain the ternary surfaces for the logarithm of the activity coefficients for silica and lime (log rslo, and log rc.~). Si0,-Fe,O: Schuhmann and Ensio have measured the activity of iron oxide in simple iron oxide-silica slags when in equilibrium with y iron. Their data recalculated to 1600°C are shown in Fig. 1. Also included is a point representing a measurement by Gokcen and Chipmana of the activity of iron oxide at 1600°C at the point of saturation with solid silica. For convenience and in accordance with other treatments,' the calculations are based on the hypothetical component, FelO, which is obtained by converting all the analyzed iron in the slag to FeO. In spite of Schuhmann and Ensio's conclusion that the activity of iron oxide in the system does not vary with temperature over the experimental range of 1258" to 1407"C, the data are corrected to 1600°C assuming that temperature does have an effect. It was felt to be most reasonable to assume that the term log rr.10 is a linear function of the reciprocal of the temperature. Reyu has indicated that an effect of temperature on the activities in this system is to be expected from the Schuhmann and Ensio data. In essence, the correction consists of multiplying the experimental value of log rf,,o by the ratio of the experimental temperature in Kelvin to 1873°K. The magnitude of the correction is not large, being approximately 11.5 pct of the experimental value of log rve10. A very minor correction was necessary to compensate for the fact that the slags were in equilibrium with y iron in the experiment, while at steel-making temperatures they would be in equilibrium with liquid iron. Data for the correction were obtained from Darken and Gurry. The standard states established are pure liquid iron oxide (FelO) in equilibrium with pure liquid iron (with the appropriate amount of oxygen in solution) and pure liquid silica. The method of plotting in Fig. 1 is convenient for the calculation of the activity of liquid silica and permits a reasonable extrapolation for the activity of Fe,O in the ranges where no experimental data are available. The uncertainty in the extrapolation to infinity at one terminal where Nvelo = 1 for the usual Gibbs-Duhem integration is reduced considerably by this method. The region of two coexisting liquid phases is estimated to range from 1.8 to 41.7 mol pct Fe,O. The nature of the activity curve for the single-phase region indicates that the activity of iron oxide across the two-phase region is very close to 0.39. Computation of the function log ~F,,o/(1— NF,,o)' for this region (dashed line) in conjunction with the curve through the adjusted experimental data indicate the best probable value of 0.382 for alPe,o in the two-phase area. The line from 0 to 0.018 Nf~~o is obtained by assuming that the component follows Henry's law. In this range, the value for log rveto is 2.59. Appropriate mathematical manipulation of the plotted linet yields the activity curves for the The curve AF", the excess molar free energy of mixing (actual minus ideal), as shown in Fig. 3 is also computed from Fig. 1. This curve is required for subsequent calculations. CaO-Fe,O: The phase diagram for the lime-iron oxide system when in equilibrium with liquid iron is not well known but there appears to be no intermediate compound present. This fact as well as the activity values for Fe,O extrapolated to the CaO-Fe,O binary from Taylor and Chipman' tend to indicate somewhat negative deviations from ideality for the activity curves for the two components. Strong indication of this is evident in Fig. 1 where are plotted the points computed from the estimated activities of Fe,O for the binary system.' It appears that the best line through the data is a horizontal straight line. Because of the general indication of the slight negative departure from ideality, the line is extrapolated horizontally to NF~,o = 0. It is con-

Jan 1, 1956

By T. F. Archbold, P. G. McCormick

Silica fiber 11arkevs and hardness irzdentatiozs have been used to study the thermal diffusion of racancies in zinc placed in temperature gradients of 460o and 706oK per Cm All markers mored toward the higher temperatures, and the data show that the heat of trarlsport Q is greater than the eizthalpy of z,acancj3 forrjalion E by an amount equal to 3.5 kcal per mole. These results ore not in agreement with those obtained in either of the two previous studies with zinc. The problem is discussed in terms of experimental differences and racancy source and sink efficiencies. THE general interest in thermal-diffusion phenomena over the past several years has prompted a number of marker movement studies using pure metals. In order to understand better the relationships between thermal and mass flow, a general goal of the experiments has been to obtain values for the net enthalpies carried by the diffusing atoms. For self-diffusion by means of the vacancy mechanism, the determination of relative marker positions before and after an anneal in a temperature gradient permits a calculation of a value for (Q - Ef). Q is the transferred enthalpy, and Ef is the enthalpy of vacancy formation in the metal being investigated. The initial experimental study of thermal diffusion in pure metals was accomplished by Shewmon who found essentially no movement of surface-hardness indentation markers in single and bicrystals of zinc held for 20 days in a temperature gradient of 310°C per

Jan 1, 1967

By Charles Brush

THE general subject of accurate pyrometry, its great development in recent years, and the importance of its application in arts and manufactures is so ably treated in other papers that this paper will bee confined to a resume of some research work on certain temperature effects in carbon and other steels, some of which appear to, be new. The results of these researches are embodied in several papers presented to' various scientific societies during the last few years, most of them under the general title of Spontaneous Generation of Heat in Recently Hardened Steel.1 Several years ago, when studying the behavior, tinder certain conditions, of specimens of hardened tool steel, I observed that they all spontaneously generated a small quantity of heat, the rate of generation diminishing from day to day for several weeks before generation became imperceptible in the sensitive calorimeter used. In each case the steel had been hardened only a few days prior to its use. It seemed highly probable that the generation of heat was associated with some sort of "seasoning" or incipient annealing process, perhaps accompanied by slight changes of volume, and that it would be most rapid immediately after hardening. I subsequently investigated this curious phenomenon more fully. Twelve ½ in. round bars of tool steel, 5 in. long and with machined surfaces, were hardened by heating to high cherry red in a reducing atmosphere of a gas furnace and quenched in cold water. The bars then had a thin strongly adhering coating of black oxide. They were next stirred in a large quantity of water at room temperature, to acquire that temperature, wiped dry, and oiled with heavy, neutral mineral oil to prevent generation of heat by further surface oxidation, wiped free of excess of oil and placed in the copper cylinder of a heat-insulated box.

Jan 9, 1919

E. L. BLOSSOM, New. York, N. Y.-That this paper deals with a real problem is illustrated by a statement made to the speaker a few months ago by the manager of a silver-lead property: "Our ore contains 60 per cent. silica on which the smelters are penalizing us heavily, and they are not able to take all our stuff even then. We have simply got to find some method other than smelting for getting the silver and lead out of our ores. We have had experts down here and have investigated flotation, leaching and volatilization, of which processes the latter is by far the most promising. We are continuing investigation." I was somewhat concerned in certain chloride volatilization experiments which we carried on in Denver in 1903, working on a carload of ore from Butte. Now being connected with the Cottrell process, by which method the fumes will undoubtedly he recovered if they solve the volatilization problem, I have looked into the matter again, and believe it can be developed into a commercial process. On a laboratory scale, working With silver-lead ores, experimenters have obtained a volatilization of over 90 per cent. of the total values in 30 to 60 min, on quantities of 1 to 5 lb., using a roasting dish and a muffle. That looks very good, and would be entirely commercial. On attempting to duplicate these results in a reverberatory furnace, they found that it is more likely to take 8 hr. firing to yield 75 per cent. extraction, which is not commercial at all, as it requires too much time, labor, and fuel, and the whole process is too slow. Of course it can be done, because we have done it in the laboratory.

Jan 1, 1918

By B. H. Bergstrom, Will Mitchell, T. G. Kirkland, C. L. Sollenberger

IN a previous article' the authors outlined a study of the variables in rod milling and also reported data from a series of open circuit grinding tests on a massive limestone in a 30-in. x 4-ft end peripheral discharge rod mill. As a second part of the experimental program, an analysis is now presented for the 30-in. x 4-ft overflow rod mill grinding under identical conditions, except that discharge ports on the periphery of the mill shell have been sealed so that the products from the present series overflowed through a 9-in. diam .opening in the center of the end plate. A variance analysis has been made of the combined data for the two experiments, and performances of the two mills are compared here. Included in the first report' were descriptions of feed preparation, rod mill circuit, instrumentation and controls, and techniques used to evaluate data. Dependent and independent variables were defined, and variance analyses were made to test the relative significance of variables and to establish magnitude of error for the experiment. Significant data were plotted in various combinations, and conclusions were drawn from the graphs. The procedure and analysis in this series of tests follows the first tests and is not repeated. Data from the second series are recorded in Table I. Listed in the first three columns are the independent variables of feed rate (1000, 2000, 3000, 4000, and 5000 1b per hr), mill speed (50, 60, 70, 80, and 90 pct of critical), and pulp density (50, 60, 70, and 80 pct). The dependent variables, Pso, P100, reduction ratio, slope of the log-log sieve analysis curve, power demand, and Bond work index follow. Of these, only the reduction ratio and the Bond work index were analyzed for significance. Production of new surface as calculated from sieve analyses has not been included for this series because of the questionable assumptions that have to be made to satisfy the formulas involved. The large number of products obtained during the runs precluded the use of surface measurement techniques by the gas adsorption methods at this time; however, samples of all products have been stored for future reference. To test the consistency of the reporting of the sieved products, an averaged sieve analysis was calculated from the wet-dry plots obtained from the three product samples of each run. The resulting averaged analysis was plotted and the P80, selected. The relative deviations of the P80's from each of the three product samples with respect to the P80 of the averaged analysis were then calculated. In only two sets were the relative deviations (6.2 and 9.9 pct) considered excessive. In each of these two sets, one sieve analysis was obviously out of line; hence that analysis was ignored and new averages were computed. This reduced the relative deviations to 1.2 and 2.7 pct respectively. The relative deviations of the product analyses with respect to their averages ranged from 0.1 to 1.4 pct at 1000 lb per hr, 0.0 to 1.1 pct at 2000 lb per hr, 0.2 to 3.0 pct at 3000 lb per hr, 0.3 to 4.3 pct at 4000 lb per hr, and 0.5 to 5.2 pct at 5000 lb per hr. The relative deviation of the 80 pct passing point for 96 dry sieve analyses of the feed with respect to that of the averaged analysis was 7.6 pct. This slightly higher percentage can probably be attributed to a greater proportion of tramp oversize in a crusher product than is ordinarily found in a rod mill product. The last column on Table I lists the adjusted work index, which has been used as the measure of efficiency for the various combinations of operating conditions investigated. Efficiency increases as the index becomes lower. It was reported in the previous paper that the work indexes for the Waukesha limestone used in these experiments decreased as the product size decreased (as calculated from Bond grindabilities). That is, this limestone becomes easier to grind as the material becomes finer. This is unusual, because the work index for most materials as calculated from the Bond grindability has remained constant as the product size decreased or has increased slightly. Table II lists the results of Bond grindability tests at all mesh sizes from 3 to 200 and the work indexes calculated from them. To remove this variation of work index with product size from the data so that results would apply to any material of constant work index, the work index values shown in Table II were plotted against product size on log-log paper. From this curve (a straight line function in this case), the expected work index for the product size for each of the runs of the experiment was obtained. The work indexes as calculated from the reduction ratio and energy consumption were then divided by the corresponding expected work index. The results obtained are reported in percentages on Table I as adjusted work index and are actually percentages of the work index for the Waukesha limestone at the size in question. Multiplication of the work index value for a material of constant index by these percentages should allow the application of the adjusted work index curves to the material. Only the adjusted work index values, not the actual experimental values, were used for the variance analyses and for the graphs.

Jan 1, 1956

By R. W. Diamond

THREE mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd. : (1) The Sullivan Concentrator, Chapman Camp, B. C. (near Kimberley, B. C.), (2) the St. Eugene Concentrator, Moyie, B. C., and (3) the Tadanac (Customs) Concentrator, Trail, B. C. Differential flotation is the only concentration method employed in all three I plants. Tables are used for pilot work only. Values in all ores treated are as minerals of some or all of the metals -lead, zinc, gold or silver. Occasional customs ores contain small amounts of copper. Sulfide iron content of ores treated varies from a [ ] low figure in some ores to 38 per cent. iron in Sullivan ore. Gangue minerals vary considerably. A few customs ores are somewhat oxidized and as a result present difficulties. Flotation equipment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sullivan Concentrator. In this paper I will not detail treatment nor equipment in any of our plants but will describe special features in, or in connection with, all of them. I will then deal with flotation reagents, describing our use of each of them, particularly where differing from general practice. I will conclude with comments on special subjects related to differential flotation.

Jan 1, 1928

J. T. Pullon, Rowangarth, Roundhay, Leeds, England :— In discussing Mr. Lee's paper, I wish to call attention to the fact that Mr. B. II. Thwaite (who was heard here yesterday on the subject of the application of blast-furnace gas for the production of power, of which he was undoubtedly the pioneer) read, at the Engineering Congress in Glasgow in 1901, a paper on the profitable utilization of power from blast-furnace gases,' in which he suggested the diversion and cleaning of the whole of the waste gases coming from the blast-furnace and their utilization for power-production, so as to obtain, with proper manipulation, from 4 to 6 times the efficiency of present methods. He suggested also the heating of the stoves with producer-gas of a higher and therefore more suitable calorific value, so as to maintain them in a constant state of maximum efficiency, free from dust, and to avoid the irregular working of the furnace, besides obtaining a maximum supply of air-blast, of 15 or even 20 lb. pressure, by means of internal-conibustion blast-engines driven by the cleaned waste furnace-gases, with a surplus of gas left for other uses. Since that time, in view of the necessity of having a stand-by plant, immediately available, in case of strikes or other reasons causing the banking or blowing-out of the blast-furnace, he has developed, as an addition to his other types of producer, a high blast-pressure gas-generator, producing a gas identical with, or somewhat superior to, blast-furnace gas; and in which all the ash of the fuel is turned into fluid slag, which is available for, the production of slagwool. The gas is a little richer in carbon monoxide than average blast-furnace waste gas, and has only from 1 to 3 per cent. of hydrogen. Fig. I, drawn from a photograph, shows a plant containing this generator, now in operation at Leeds. It is made in units of from 1,000 to 10,000 h.p. capacity for each vessel, and coupled,

Jan 1, 1907

By F. Julius Fohs

Centrally located with relation to the largest iron- and steel-producing districts of the United States, the fluorspar-deposits of Kentucky possess increasing interest and importance. As typical of the numerous fluorspar-mines of Kentucky and Illinois, I have selected for description the Memphis, because it and others of its immediate group exhibit the conditions characteristic of all. I. The Memphis MiNe. This mine lies 5 miles NW. of Marion, in Crittenden county, Kentucky, a station on the Chicago and Nashville division of .the Illinois Central R. R. For the first mile and a half out of Marion we see only Birdsville or Middle Chester sandstones of Mississippian age. Then we cross a fault of about 850 ft. displacement, and the Ste. Genevieve oolite sets in. Beyond the fault, oolite is the predominant rock, except that the hills to the north have a capping of Cypress or lowest Chester sandstone, 80 ft. below which is an outcrop of from 6 to 10 ft. of Ste. Genevieve (Rosiclare) sandstone. Occasional sink-holes are noticed, and as the mines are approached evidence of faulting is again seen. A line of .crude head-frames and open-cut dumps, extending for more than a quarter of a mile, marks the Klondike vein. The open-cuts are from 15 to 20 ft. deep, and in most of them, from the surface down, was found the reddish gravel which is really fluorspar—some of it white or purple and crystal-clear (if the red clay is washed off), and some carrying iron and silica, and stained by waters from the decaying limestone walls. In one of these cuts, at a depth of 20 ft., white and purplish honey-combed fluorspar was found, in which the larger cavities are due to the leaching of limestone and calcite, and the minute ones to the leaching of zinc-hlende.

Jan 1, 1910

By G. R. St. Pierre, A. Ghosh

In the Si-C-0 system at temperatures of interest in process metallurgy there are four stable condensed phases—silicon, carbon, silica, and silicon carbide (Sic). Silicon melts at 1683oK1 and shows negligible solubility for carbon and oxygen at 1700°K. However, silicon dissolves approximately 1.5 at. pct C at 2500oK.2 Carbon in the form of graphite remains pure and dissolves negligible amount of silicon.' Silica (crysto-balite) melts at 2001°K' and is essentially a stoichio-metric compound. Silicon carbide is a solid and shows negligible deviation from stoichiometry up to approximately 2800oK.2 Besides the condensed phases there is a gas phase

Jan 1, 1970

By R. A. Vandermeer

It is usually assumed that the rate-determining step in the migration of a grain boundary involves the thermally activated transfer of single atoms across the interface. Chemical reaction rate theory then gives a migration rate which is proportional to the driving force when this is small compared to kT.1 In their recrystallization studies on aluminum, Gordon and vandermeer2 obtained data which was capable of providing the first experimental test of this proportionality. They correlated stored energy (driving force) release measurements determined calorimetrically with fraction recrystal-lized kinetic (growth rate) data acquired metallo-graphically at a temperature where a significant amount of recovery takes place concurrently with recrystallization. Within experimental error, the results of Gordon and Vandermeer confirmed experimentally, at least over a limited range, the linear dependence of boundary migration (growth) rate on driving force in accordance with theory. In obtaining these results, however, an incorrect, implicit assumption was made in relating the average instantaneous growth rate of the recrystallized grains to the measured fraction recrystallized kinetic data. The purpose of this present note is to point out and correct this assumption. An alternate approach, whereby a more proper average growth rate can be calculated from the recrystallization kinetic data, is presented. The earlier data, reevaluated in terms of this new approach, show the same general trend as before so that the original conclusion of Gordon and vandermeer2 is still valid. As was shown in a detailed study3 of the geometrical features of recrystallization in aluminum, the colonies of recrystallized grains can be regarded as uniform cylinders embedded in a three-dimensional matrix, the number of such colonies being constant. Thus during the early stages of recrystallization the volume fraction recrystallized, Xv, can be written as Xv=ynvlr2 [l] where y is a shape factor and i and r are defined as the average length and radius of a recrystallized colony and are spatial averages over the specimen. -nv, is the number of such colonies in a unit of volume. The erroneous assumption made in the earlier paper2 was that r in Eq. [I] could be replaced by

Jan 1, 1965

WE the undersigned, being all persons of full age and citizens of the united States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerab and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said association are designated by the rules thereof Members of its Council; that the undersigned are all members of said Council as the same was constituted on the 20th day of December, 1904. III. That on said last-mentioned date a regularly called meeting of said association was held at its office in the Borough of Manhattan, City of New Pork; that thirty days before such meeting notice of the intention to incorporate said association was given by mail to each member thereof whose residence or post-office address is known; that at said meeting the following resolutions were offered, seconded and duly adopted by the unanimous vote of all its members then present, to wit: "Resolved, That it is the sense of the members and associates of the American Institute of Mining Engineers in general meeting assembled that it is desirable and necessary for the well being of said association and its members and for the furtherance of the objects for which the same has been formed, that said association lncorporate under the Membership Corporations Law of the State of New york; "And Further Resolved, That the Members of the Council of this Association, or a majority thereof, be and they hereby are authorized, in accordance with the provisions of Section 5 of Article I. of the Membership Corporations Law, to incorporate this association for the same purposes for which it has been organized and conducted, in the manner provided in Article 11. of said law; "and Further Resolved, That the name of said corporation as hereby adopted by this meeting shall be American Institute of Mining Engineers; "And Further Resolved, That the said incorporators shall be named in the Certificate of Incorporation as directors of such corporation until its first annual meeting, and that such directors and their successors in office shall be and they hereby are authorized to enact and adopt a Constitution and By-Laws for the government of said corporation." IV. That the name of the proposed corporation is American Institute of Mining Engineers. V. That the purposes for which this corporation is to be formed arc: To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members the information thus obtained, and to establish and maintain a place for meeting of its members, and

Jan 1, 1929

By Will Mitchell, T. G. Kirkland, C. L. Sollenberger

R. S. Handy (Santa Rosa, Calif.)—It would be interesting to learn the comparative results of treating the Korean scheelite ore described in this paper according to the following procedure: I—Follow the procedure described in the paper to the recovery of the sulphides by flotation. 2—Dilute the residue from the sulphide flotation strongly with water and disperse the contained colloids by adding a mixture of 75 pct sodium silicate and 25 pct quebracho to dispersion point. 3— Settle the dispersed pulp and decant the supernatant colloids. 4—-Dilute, settle, and decant the pulp until the settled residue is crystalline. Not over 10 pct of the tungsten minerals should follow the colloids. 5—Treat the settled residue by flotation, having established the proper pH. Oleic acid homogenized with cresylic acid or kerosene is more selective for scheelite than is oleic acid alone. (The recovery of the contained tungsten minerals should be practically complete in this operation.) 6—Deflocculate the tungsten concentrate from step 5 with the same dispersion agents as in step 2 and treat the deflocculated pulp by gravity. The minerals that tend to float with scheelite are generally of low specific gravity and the separation is efficient. The heavier contaminants, such as pyrrhotite and magnetite can be removed magnetically, leaving a practically pure scheelite. E. J. Pryor (Imperial College of Science and Technology, London)—It occurred to me that instead of using temperature as a differentiating control, more precision might be obtained with a reagent of a type we developed here for the flotation of high grade fluorspar in cold pulps. This reagent, which is manufactured on a modest scale in England, is based on oleic acid, which has been modified by our patented process to ensure complete stable dispersion at any desired concentration in water. It thus becomes possible to utilise unimolecular layers with good selectivity. In the fluorspar flotation for which we developed it, it is possible to hold a tight control on depressing quebracho for the calcite without substantial loss of flu-orite, and recovery exceeding 99 pct is not uncommon in the mill where it is in use, even under wintry conditions. No attempt has been made yet to extend the use of the reagent, as we have not completely overcome

Jan 1, 1952

By William Hutton Blauvelt

The type of gas producer in which the ashes are fluxed and run off as slag was among the very earliest made. Ebelmen built the first one in 1840 at Audincourt, France, only a year after the installation of the first gas producer of which we have record. Charcoal was used as the fuel, with blast-furnace slag and clay as flux. My interest in this type of producer began when as a boy I saw the fluxing producer at Chester, N. J., which was invented by W. J. Taylor, and described by him in 1881.' This producer was invented independently by Mr. Taylor to meet the difficulties he experienced in making producer gas for roasting sulphurous iron ores. It will be of interest to review briefly his description of his producer. It was built like a small blast furnace, having a hearth 24 in. in diameter and 24 in. high. The bosh angle was 25' from the vertical; the diameter at the bosh 4 ft. and at the top 3 ft.; the total height 12 ft. The producer contained one water-cooled tuyere 12 in. above the bottom, with a 1.5-in. nozzle. Depth of the coal above the tuyere, 6 ft. Mr. Taylor mixed the coal with from 30 to 40 per cent. of basic blast-furnace slag to flux the ash. Occasionally some limestone was also used, but never limestone alone, as the use of the furnace cinder gave a larger volume of slag and made it easier to maintain a proper fluidity. The producer was blown with a small Weimer blowing engine, delivering 300 ft. of air per minute, at from 1 to 1.5 lb. pressure. The slag was tapped every 2 hr. and was black and glassy in appearance. Broken or egg size anthracite was used. The fine sizes of anthracite could not be made to work. Mr. Taylor expressed the belief that bituminous coal could be used if not too fine, but no experiments were made with this coal. Runs were made of four weeks' duration, with no stops or changes. Mr. Taylor reported the following advantages: 1. Excellent gas, very uniform in quality. The high fuel bed permitted no air to pass unconsumed, and the gas was almost entirely free from carbonic acid.

Jan 1, 1914

By Paul Gordon, A. S. Iyer

Apreliminary investigation has been carried out on the annealing behavior of explosively deformed copper as compared to that of conventionally deformed copper, using hardness, stored energy, and the sharpening of X-ray spots on Debye rings as the measures of annealing. Some metallographic observations were also made. Two purities of copper were studied. The first was tough pitch copper obtained as a small piece from the guard ring of a sample explosively deformed to approximately 500 kbars.* The second consisted of mentedand deformed these samples quite badly so that only a few small fragments were available for the annealing experiments. As a result, little in the way of quantitatively significant data was gleaned from the measurements. However, several important qualitative differences between the annealing of explosively deformed and conventionally deformed copper have been observed. It is these effects which are described in this report. Fig. 1 presents the results of hardness and stored energy measurements during the annealing of the high-purity copper after explosive and after conventional deformation. The data for the conventionally deformed copper were taken from the work of Gordon;' in this copper it is evident that most of the stored energy is released concommittantly with the hardness drop. As shown in orddon's' investigation, these effect:: are definitely associated with recrystal-lization. In the case of the explosively deformed copper, on the other hand, a large fraction of the stored energy is released before any appreciable hardness change takes place. At 160°C about 40 pct, and at 170°C about. 80 pct, of the stored energy appears to have been released prior to the onset of softening, i.e., undoubtedly prior to recrystallization. In view of the facts that the hardness and energy measurements were made on separate samples and that there is reason to suspect that the intensity of the explosive deformation from sample to sample may not have been uniform, a check run was carried out in which both energq release and hardness changes were measured cnn the same sample. The results of this run, shown in Fig. 2, confirm the conclusion that much of the stored energy is released before the hardness begins to change appreciably. In an effort to obtain some idea of the activation energy associated with the early release of energy, a single callorimetric sample was annealed in two steps, first at 149.5"C and then at 159.5"C, Fig. 3.

Jan 1, 1962

By C. Feng, I. R. Kramer

A study was conducted to determine the influence of the surface on the yield point of fcc metals and high-purity iron. For the high-purity fcc metals, the yield Point produced by restraining a specimen may be eliminated by removing a sufficient amount of the layer. A yield point similar to that in fcc metals was found when iron specimens were pre-strained after a prior deformation. This yield point is not due to an aging effect but is associated with the surface layer. The yield points in age-hardenable aluminum alloy and those connected with "work softening" are not affected by a surface-removal treatment and are, therefore, caused by bulk-type dislocation reactions. The yield point which appears in previously strained fcc metals has been the subject of numerous studies. Several theories have been advanced to explain this "unloading-reloading" yield point. Cottrell and stokes,' from their study on the effect of temperature on plastic properties of high-purity aluminum, considered that it was the result of an avalanche "breakdown" of Lomer-Cottrell sessile dislocations. Haasen and Kelly2 extended this concept of dislocation-dislocation interaction to account for the yield point when unloading and reloading was carried out at the same temperature. On the other hand, strain aging was found to be responsible for the yield point in A1-Mg alloy by Westwood and Broom,3 and in aluminum alloys containing various amounts of alloying elements by Smallman, Williamson, and Ardley.4 In these cases, the yield point is considered to be associated with the locking of dislocations by impurity atoms. Birn-baum and filer5,6 and Takamura and muira7 reported that, when a high-purity copper specimen was prestrained, then held at a lower stress, and finally reloaded at the prestrain temperature, a larger yield point was observed. Such an increase was attributed to the locking of dislocations by point defects. In addition, Bolling8 suggested that both mechanisms, i.e., dislocation-dislocation interaction and strain aging, are responsible for the yield phenomenon, at least in a brass. Thus, there appears to be experimental evidence for both the strain aging and dislocation-dislocation interaction theories to explain the yield point in the fcc metals and alloys. In a previous article,9 one of the authors observed that, if sufficient amounts of metal were electrolti-cally removed after deformation of a high-purity aluminum single crystal, the yield point did not appear upon reloading. Continued pursuit in this area revealed that the effect of the surface on the yield-point phenomenon is not limited to one metal but affects a variety of metals of different lattice structures. Nor is the effect limited to the yield points produced by simple unloading-reloading at constant temperature; the surface exerts an important role on the yield point even when the temperature is changed at some stage during the test. It is the intent of the present article to give additional information regarding the effect of the surface on the yield-point phenomenon and to show the association between the yield point in both fcc and bcc metals and the existence of a heavy concentration of dislocation in the region near the surface of a deformed specimen.10 EXPERIMENTAL Materials. The single crystals used in this study had a nominal cross section of 0.125 by 0.125 in. and a 3-in. gage length and were prepared by a modified Bridgman technique. The initial purity for the metals was 99.997, 99.999, and 99.999 pct for aluminum, copper, and gold, respectively. Bar stock of these same materials was used in the preparation of the polycrystalline specimens of aluminum and copper. The iron specimens were machined from rods of "ferrovac", reported to have a purity of 99.98 pct. In addition, a precipitation-hardening aluminum alloy, containing 1.5 pct Cu, 2.5 pct Mg, and 5.5 pct Zn, was used. The polycrystalline specimens of iron, copper, and the aluminum alloy had a diameter of 0.17 in. and a gage length of 2 in. while the high-purity aluminum specimen had a nominal rec-

Jan 1, 1965

Discussion of the paper of ALBERT SAUVEUR, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 93, September, 1914, pp. 2439 to 2449 G. K. BURGESS, Washington, D. C.-This very instructive contribution by Professor Sauveur to our knowledge of that puzzling substance, Hadfield's manganese steel, should not only be read in connection with the paper of Messrs. Hopkinson and Hadfield referred to by Professor Sauveur (Bulletin No. 87, pp. 513 to 530, March, 1914); but one should also have in mind, as throwing much additional light upon the questions raised, two papers recently presented before the Iron and Steel Institute, the one by Sir Robert Hadfield (Journal of the Iron and Steel Institute No. II, 1913) on Heating and Cooling Curves of Manganese Steel, the other by Messrs. Hadfield and Hopkinson (ibid., No. I, 1914) treating of the Magnetic and Mechanical Properties of Manganese Steel. We then have brought together for this substance, the thermal, magnetic, and mechanical properties as well as the resulting microstructure, for the definite heat treatments described, and in particular after long annealing between 500° and 700° C. Sir Robert Hadfield and Professor Hopkinson see in the properties found for manganese steel (of C = 1.25 and Mn = 12.5 per cent.) a demonstration of the untenableness of the allotropic theory of iron, whereas Professor Sauveur reaches the contrary conclusion, that some of the facts observed can be explained only in terms of the existence of beta iron in steel of this composition. There is another possible hypothesis: namely, that these several series of experiments shed no light on the subject of the allotropy of iron, or at least as regards the existence of beta iron. However heretical it may sound, I am inclined to this last belief.

Jan 4, 1915

By Zay Jeffries

THIS paper will include a brief discussion of Prof. Howe's paper on The Supposed Reversal of Inheritance of Ferrite Grain Size from that of Austenite.1 The general subject of grain refining in steel and iron will also be treated. The conclusions reached are stated in the following hypotheses which are discussed more in detail below. 1. The ferrite grain size in pure iron, the ferrite and pearlite grain size in hypoeutectoid steel, the pearlite grain size in eutectoid steel and the cementite and pearlite grain size of hypereutectoid steel are not inherited from the grain size of the mother austenite. 2. The only structural feature that is generally inherited from the austenite of hypo- and hypereutectoid steels on cooling through their transformation ranges is the position of the excess ferrite or cementite at the austenite grain boundaries, sometimes causing complete and sometimes incomplete networks which outline the old austenite grain boundaries. Rapid cooling through the transformation range will cause the non-inheritance of this structural (network) feature. 3. The austenite grain boundaries themselves are nearly always effaced in all steels and also in pure iron during the Ar transformations. 4. The grain-size refining of steel and iron is brought about by the combined. effect of non-inheritance of the transformation products on either heating or cooling, i.e., the austenite transformation .products do not inherit their grain size from the austenite on cooling through the transformation range for does austenite inherit its grain size from the products which form austenite on heating. 5. In general, in both iron and carbon steel the larger the austenite ,grain size, the larger will be the grain size of the transformation products on cooling. This, of course, assumes all other conditions constant except the austenite grain size. An exception is found to this general rule in very pure iron such as electrolytic iron. 1n this instance small austenite grains may form very large ferrite grains on cooling through Ar3.

Jan 11, 1917

WE the undersigned, being all persons of full age and citizens of the United States, and a majority residents of the State of New York, desiring to form a corporation pursuant to the provisions of the Membership Corporations Law for the purpose of incorporating, as provided in Section 5 of Article I. of said law, the existing unincorporated association known as American Institute of Mining Engineers, do hereby make, acknowledge and file this Certificate for that purpose, and do Certify as follows: I. That the American Institute of Mining Engineers is an unincorporated association organized and existing with the object of promoting the arts and sciences connected with the economic production of the useful minerals and metals and the welfare of those employed in these industries by means of meetings for social intercourse and the reading and discussion of professional papers, and to circulate by means of publications among its members and associates the information thus obtained. II. That the persons duly appointed or designated to manage the affairs of said -association are designated by the rules thereof Members of its Council; that the undersigned are all members of said Council as the same was constituted on the 29th day of December, 1904. III. That on said last-mentioned date a regularly called meeting of said association was held at its office in the Borough of Manhattan, City of New York; that thirty days before such meeting notice of the intention to incorporate said association was given by mail to each member thereof whose residence or post-office address is known; that at said meeting the following resolutions were offered, seconded and duly adopted by the unanimous vote of all its members then present, to wit: "Resolved, That it is the sense of the members and associates of the American Institute of Mining Engineers in general meeting assembled that it is desirable and necessary for the well being of said association and its members and for the furtherance. of the objects for which the same has been formed, that said association incorporate under the Membership Corporations Law of the State of New York; "And Further Resolved, That the Members of the Council of this Association, or a majority thereof, be and they hereby are authorized, in accordance with the provisions of Section 5 of Article I. of the Membership Corporations Law, to incorporate this association for the same purposes for which it has been organized and conducted, in the manner provided in Article II. of said law; "And Further Resolved, That the name of said corporation as hereby adopted by this meeting shall be American Institute of Mining Engineers; "And Further Resolved, That the said incorporators shall be named in the Certificate of Incorporation as directors of such corporation until its first annual meeting, and that such directors and their successors in office shall be and they hereby are authorized to enact and adopt a Constitution and By-Laws for the government of said corporation." IV. That the name of the proposed corporation is American Institute of Mining Engineers. V. That the purposes for which this corporation is to be formed are: To promote the arts and sciences connected with the economic production of the useful minerals and metals, and the welfare of those employed in these industries by all lawful means; to hold meetings

Jan 1, 1928