Search Documents

Recognizing the fact that the problems of the committee named by the Board to prepare the "official ticket" for officers and Directors of the Institute are various and difficult; and desiring to assist this committee by setting forth some of the principles that should guide the committee and some of the qualifications that should be required of candidates, the following instructions are formulated and the Secretary is directed to publish them in MINING AND METALLURGY concurrently with the publication of the names of each newly appointed Nominating Committee and to send a copy to each member of the Committee. Each year the Nominating Committee is to select "official" candidates for eight places, as follows:, (1) President and Director (2) Vice-President and Director (3) Vice-President and Director (4) Director (5) Director (6) Director (7) Director (8) Director

Jan 1, 1939

By William E. Ford, Edward Salisbury Dana

Normal phosphoric acid is H3P04, and consequently normal phosphates have the formulas R3PO4, R3(P04)2 and RPO4, and similarly for the arsenates, etc. Only a comparatively small number of species conform to this simple formula. Most species contain more than one metallic element, and in the prominent Apatite Group the radical (CaF), (CaCI) or (PbCI) enters; in in the Wagnerite Group we have similarly (RF) or (ROH).

Jan 1, 1922

By H. S. Cannon, F. N. Rhines

IT. H. Hausner( Sylvunia Electric Products Inc., Bay-side, N. Y.)—The results reported by the authors are interesting because they contribute some information on the principles of sintering and also because of a certain practical value for the manufacture of powder . metallurgical parts in production. Pressed powder compacts are frequently sintered in a boat in several layers so that the lower layers are actually sintered under the weight of the upper layers and, therefore, are frequently deformed. The authors gave information on this deformation process by determining the effect of the load on the density. The experimental setup of the authors, however, has a disadvantage—that the sintering occurred in a cylindrical container so that the deformation was stopped in the direction of the diameter. The authors should have rather called this a study of hot-pressing than of sintering. I want to call the attention of the authors and others interested in sintering under load to the experimental work described by Dawihl and Rix.' These authors sintered cylindrical compacts under a lengthwise ten-sional load of 0 to 25 g and found that the shrinkage in length and diameter changes considerably with the load, but that the volume shrinkage is affected very little by the load. H. S. Cannon (authors' reply)—We wish to thank Dr. Hausner for calling attention to the experimental work of Dawihl and Rix. The fact that they found volume shrinkage little affected by varying tensional loads during sintering seems to support the contention that the forces due to loading are equivalent to and additive to the forces which cause densification. This contention is the basis of our comparison of sintering and creep.

Jan 1, 1952

By W. S. Burbank, B. S. Butler

STUDY of the ore deposits of Colorado has disclosed, in numerous places, sharp changes in both mineralogy and metal content of the primary or hypogene deposits with change in depth. A clear understanding of the meaning of these changes is requisite to form intelligent conclusions that can be applied in the exploration of such ore deposits. This paper is an attempt to set forth some of the geologic and chemical relations of minerals that bear on this problem. The effect of the differing electrode potentials of elements on the order of oxidation and on the order of displacement of one metal by another metal in supergene sulfide deposits has been studied for many years by several investigators. The results all agree rather closely with the original Shurmann series of replaceability of metal sulfides, as Wells has shown.1 So far as the writers are aware there has been little attempt from the geologist's viewpoint to correlate the electrode potentials of the elements, other than those of the common metals, with the positions and mode of combination of the elements as found in ore deposits, and in particular in hypogene deposits. Wells2 discusses electrochemical activity between solutions and certain ore minerals and mentions the possibility of its effect in precipitation reactions. The senior writer for a number of years has emphasized the importance of oxidation-reduction reactions as a factor in the formation of certain hypogene ore minerals, and as the electrode potentials are a measure of the relative Oxidizing and reducing power of the elements and their ions, it seems possible that a study of them may offer some suggestions on certain problems. The data at present available for such a line of

Jan 1, 1929

By G. Sachs, C. C. Chow, L. J. Klingler

Most structural parts which are heat treated are designed using strength properties which have been determined in the principal direction of the wrought material. For example, for rolled or drawn materials, properties are given for the rolling or drawing direction. The structures, however, may be loaded so that the critical stress is in some direction other than that for which the properties of the material are known. Investigations of forged products,123 have shown that while the yield strength and tensile strength of carbon steel billets and bars vary little with the direction of the test specimen in relation to the fiber, the contraction in area in tension tests and the impact strength in notched bar impact tests decrease in the transverse direction. The contraction in area and, consequently, the fracture stress of hard aluminum and magnesium alloy forg-ings have also been found to be lower in the transverse direction. An investigation on aluminum alloy plate4 likewise has shown the dependence of the fracturing characteristics upon the direction* of the test specimens, the longitudinal direction being considerably stronger than the transverse direction and the normal direction, with the normal direction being the least strong. The variation of properties with direction has been explained by a type of anisotropy called mechanical anisot-ropy. This anisotropy results from the elongation, in the direction of the principal strain, of certain phases, inclusions, and/or cavities in the metal during working. A mechanical fibering is thus produced which seems to persist through annealing and heat treatment. This investigation was initiated to determine the flow stress and fracture stress, at high hardness levels, at 90° to the rolling direction in a round steel bar. It is this direction which receives the critical stress in drawing dies machined from round bars. Preliminary tests showed a large difference in properties between the 0° and 90° directions. Consequently, it was felt that a more complete investigation, utilizing several types of tests, was warranted to determine the flow and fracture characteristics of a steel at various orientations, for a number of hardness levels. This investigation was conducted on an air hardening nondeform-ing die steel. Material and Procedure The distribution of properties was made on a 3-in. round bar of annealed high-carbon, high chromium steel of the following analysis: Pct Carbon................... 1.53 Manganese................ 0.39 Silicon.................... 0.27 Chromium................ 11.76 Vanadium................. 0.25 Molybdenum.............. 0.81 The 3-in. bar was produced from an 8-in. ingot, which was annealed and forged to a 4-in. square billet. The billet was annealed and rolled to a 3-in. round which was then annealed and straightened. This steel is an air hardening die steel which has very good dimensional stability on hardening; therefore, the residual stresses resulting from hardening would be expected to be low. A hardness survey across the diameter of the annealed bar showed no difference in hardness from the center to the outside. However, the test sections of all the specimens were taken approximately half way between the center of the bar and the surface to avoid any surface effect or possible porosity at the center. Tension, compression and bend tests were made on specimens hardened and tempered at six different temperatures. The tension test specimens, Fig 1, were machined from the bar at orientations of 0, 22.5, 45, 67.5 and 90° from the axis of the steel bar. The specimens were rough machined, heat treated and then ground to size. The test section on each specimen was lapped in a direction parallel to the axis of the specimen to remove any transverse scratches which might act as stress raisers. The specimens were tested in fixtures which insured concentricity of loading of less than 0.001 in.5 The transverse strains were measured with a radial strain gauge,5 the least count of which was 0.0001 in. change in diam. The compression specimens, Fig 1, were machined from the bar at ori-

Jan 1, 1950

By C. A. Allen

FOR over three years we have been endeavoring to reduce the number of fatalities and minor accidents in Utah. The physical condition of the o? Represents the average of 4 States mentioned excluding the catastrophes indicated. FIG. 1.-NUMBER KILLED PER MILLION SHORT TONS OF COAL PRODUCED IN COLO¬RADO, NEW MEXICO, UTAH, WYOMING, AND BITUMINOUS MINES OF THE UNITED STATES, 1914 TO 1920. mines, concentrators, and smelters is good, yet the number of accidents,

Jan 5, 1922

As already announced, the Arizona Meeting of the Institute is to be held from the 18th to the "25th of September. There will be a special train from New York City to Arizona and return, to take members and guests of the Institute to the meeting., The Committee in charge consists of Walter Douglas, Chairman, Cleveland E. Dodge, John C. Greenway, Arthur S. Dwight and Julius Kruttschnitt, Jr., and while the plans of this Committee are not complete, it may he announced that 'the train will be run with the requisite number of Pullman, dining and baggage cars to accommodate those who desire to go, which will accompany the party during the entire week of the Arizona Meeting as per the following program, including, of course, the visit to the Grand Canyon. It is especially desirable that the Committee should know, at as early a date as possible, the number of those who desire to make the trip; and those who desire special accommodations such as drawing rooms, state rooms, etc., are especially requested to communicate as soon as possible with the Secretary of the Institute, stating the number in their party.

Jan 6, 1916

The Mineral Industry, Published by McGraw-Hill Book Co, New York, N Y. The Mineral Industry is an annual review of the mineral industry It is a standard and complete reference on the mineral industry for the year covered Through the cooperation of the A I M E its publication in 1933 was made possible Mineral Industry for 1930 contains sections devoted to the production, consumption, trade, market, uses and technology of the following headings: Abrasives, aluminum and bauxite, antimony, arsenic, asbestos (b), asphalt, barium and strontium, chromium (b), coal and coke, cobalt (b), copper, diatomite, fluorspar, gold and silver, graphite, gypsum, iron and steel (b), lead, magnesite, manganese, mica, molybdenum, nickel, petroleum and petroleum products, phosphate rock (b), platinum group metals (b), potash, precious and semiprecious stones (b), quicksilver, radium (b), uranium and vanadium, slate (b), sodium salts, sulfur, pyrite, sulfuric acid, talc and soapstone, tin, titanium and zirconium, tungsten (b), zinc, minor metals, minor nonmetals, ore dressing and coal washing (b). Sections marked (b) have appended a bibliography of recent literature on the subject. Each section is written by an acknowledged expert. Other volumes contain similar material Prices -The Mineral Industry, 1892-1930, vols. 1 to 39. Complete sets of this work, uniformly bound, except vols 25 and 26,

Jan 1, 1933

By E. J. Haug, K. L. Clifford, K. L. Purdy

St. Joe’s Minerals Corp.’s Southeast Missouri Mining and Milling Division produces lead, zinc and copper sulfide concentrates at three of its operations. The Viburnum and Fletcher mills have been described in previous papers. The new Bushy Creek mill, dedicated in May of 1973, is an updated version of the Fletcher mill incorporating 8.5m3 (300 cu ft) lead and zinc

Jan 1, 1980

By C. E. Schwab

A lead-zinc orebody, in fairly strong quartzite and with a dip of 35° to 60°, is block-caved by use of scrams in a stair-step pattern up the ore footwall. Scram linings to handle coarse muck and permit the use of folding scrapers are developed by the use of end-grain wooden blocks to reduce maintenance and keep operating cost to a minimum.

Jan 10, 1953

By J. M. Callow

THe results obtained by pneumatic flotation throughout the country on all classes of ore, and the tonnage now being treated by this particular method, speak for themselves. Its advantages over the so-called agitation process are now established by facts and data from practicc. The comparative efficiency of a rapidly revolving paddle, as a means for aerating an ore pulp, and of a cyeloidal or turbine blower for the same purpose, would seem to be so obvious as to leave no room for discussion. Practitioners in this art are to be congratulated on the acquisition of the valuable literary contributions that have recently been made on the theory of flotation by Messrs. Ralston, Van Arsdale, Taggart and Beach, and others, and the very valuable and able articles by Messrs. Laist and Wiggin on "Flotation Concentration at Anaconda, Mont.," by Dr. Rudolf Gahl on the "History of Flotation at Inspiration," and by David Cole on "The Advent of Flotation in the Morenci District." It is not within the province of this article to attempt an answer to the various issues raised in regard to the theory, or to defend the one advanced by me a year ago. But since discussion usually benefits the profession, a reply will be made to some of the statements made by the last-named writers. CoMPABATIVE SENSITIVENESS AND ATTENDANCE Concerning the article, "Flotation Concentration at Anaconda, Mont.," by Laist and Wiggin, a little explanation is in order. It should be stated that, with the exception of about 24 days at the end of the testing period, the Callow experimental plant at Anaconda was not run under my direction. This perhaps accounts for some of the concIusions drawn on page 499 of the descriptive paper. The conclusion that the use of acid seems to be of considerable advantage, calls for some comment. While the tests conducted by the Anaconda Copper Co. do show acid to be of considerable benefit, this is a consequence of using acid sludge as a flotation agent. My belief has always been that the Anaconda

Jan 1, 1917

By Frank C. Kelton

It is perhaps not widely realized that extraction and saturation processes carried out on oil well core samples alter the properties of these samples to varying degrees. On the other hand it is felt by some that quick-freezing of core samples increases their permeability and porosity significantly. Accordingly, laboratory tests were carried out on 49 pairs of horizontally adjacent samples in order to differentiate between the effect of quick-freezing per se on permeability and porosity of the samples, as distinguished from the effect of the identical saturation treatment on permeability and porosity of the companion samples. Also, additional field data were obtained on comparison of frozen vs unfrozen companion samples. LABORATORY INVESTIGATION OF FREEZING us SATURATION EFFECTS Procedure The samples used in these tests were two-cm cubes cut in horizontally adjacent pairs from cores from eight Gulf Coast and Mid-Continent wells, which cores had not previously been frozen. These samples were extracted with carbon tetrachloride, dried, and air permeabilities run in the conventional manner. They were then evacuated and saturated with brine of 25,000 ppm sodium chloride content, and porosities determined by gain in weight. The samples were partially desaturated by evaporation down to an average brine saturation of 68 per cent. One sample from each pair was quick-frozen by covering with dry ice after wrapping in a single layer of paper, and allowed to remain frozen for about two hours; the companion sample from each pair was not frozen. After thawing the frozen sample, all samples were immersed in tap water overnight in order to leach out most of the brine. Air permeabilities were re-run, and the samples were again saturated with brine to determine a second porosity value. For purposes of averaging of data, the samples were grouped according to four permeability ranges, from 0 to 10, 10 to 100, 100 to 1,000, and 1,000 to 3,840 md. Average permeability and porosity changes for the frozen vs the unfrozen adjacent samples are shown in Table 1. Discussion As may be seen from Table 1, the averages of the per cent permeability increases for the quick-frozen samples ranged from 3.8 to 12.9 per cent among the four permeability groups. The average changes among the four groups of unfrozen companion samples ranged from a decrease of 0.2 per cent to an increase of 9.3 per cent. There was no particular correlation of these changes with magnitude of permeability; however, the increase for each group of frozen samples paralleled the increase for the corresponding unfrozen samples. The differences between the two sets of values are believed to be a valid indication of the effect of the quick-freezing in itself, since the treatment of the two samples in each pair was identical except for freezing. The permeability changes which are strictly the result of the quick-freezing are shown in the sixth column of Table 1. These range from a decrease of 0.9 per cent to an increase of 4.0 per cent; the overall weighted average is 1.2 per cent, as compared to an average increase of 6.8 per cent caused by the saturation treatment of the samples not frozen. The average porosity changes are in general smaller than the changes in permeability, and range from a decrease of 2.3 per cent to an increase of 3.3 per cent. The overall weighted average change ascribed to the quick-freezing is 1.0 per cent of porosity. Many factors can contribute to the changes in permeability and porosity observed when subjecting cores to the simple processes used in these tests. Such are: hydration and swelling of clay, adsorption of ions, changes in surface structure and wettability, expansion and compression effects due to ice formation, shrinking and cracking, leaching of salts and colloids, displacement of particles resulting in either blocking or enlarging of pore openings. Whatever particular mechanisms are involved. however, it is apparent not only from this study but also from other investigations in the literature' not directly concerned with quick-freezing, that the effects produced by commonly used extraction, saturation and drying techniques may be of considerable magnitude The results of this study indicate that for the particular samples and techniques used, such effects are of the order of five to six times the effect of quick-freezing. insofar as changes in permeability are concerned. It may be argued that these samples might not include extremely shaly material where the effect of freezing upon permeability may be much greater. However, had such material been available for these tests, it would undoubtedly have been very susceptible also to alteration by the extraction and saturation treatment used. To investigate this point further, the individual sample data were re-grouped according to the magnitude of the average per cent permeability increases for the pairs of samples, irrespective of permeability. The results

Jan 1, 1953

By Khosrow Bakhtar

A series of nineteen shear tests were performed on fractures 1 m2 in area, generated in blocks of sandstone, granite, tuff, hydro- stone and concrete. The tests were conducted under quasi-static and dynamic loading conditions. A vertical stress assisted fracturing technique was developed to create the fractures through the large test blocks. Prior to testing, the fractured surface of each block was characterized using the Barton JRC-JCS concept. The results of characterization were used to generate the peak strength envelope for each fractured surface. Attempts were made to model the stress path based on the classical transformation equations which assumes a theoretical plane, elastic isotropic properties, and therefore no slip. However, this approach gave rise to a stress path passing above the strength envelope which is clearly unacceptable. The results of the experimental investigations indicated that actual stress path is affected by the dilatancy due to fracture roughness, as well as by the side friction imposed by the boundary conditions. By introducing the corrections due to the dilation and boundary conditions into the stress transformation equation, the fully corrected stress paths for predicting the strength of fractured blocks were obtained.

Jan 1, 1984

By T. Reed Scollon

Coal reserves of the Rocky Mountain area are vast and are more than adequate to meet significantly increasing demands in the immediate future. Practically all of the increase in coal demand for the next decade or so will be in the electric power utility sector. All ranks of coal are available in the area, and from a technological viewpoint, all are suitable for electric power generation. Location of economically recoverable coal deposits, location of generating plants with respect to power demand areas and sources of cooling water, and availability and price of other fuels are the major factors which, individually or in combination, will determine the ultimate selection of Western coal deposits to be developed for electric power generation. The low sulfur content of most western coals and the non-urban location of many power plants should tend to minimize problems of air pollution. If projections for nuclear power prove correct, increases in demand for Rocky Mountain area coals beyond about 1980 will depend primarily on the extent of commercial development of synthetic fuel processes. Current research activities on the conversion of coal to liquid and gaseous fuels are promising. Most western coals range in rank from lignite through high-volatile bituminous coals and are particularly amenable to conversion. Vast reserves of Rocky Mountain coals have long lain dormant primarily because of their remoteness from major market areas. Recently, however, innovations in coal transportation and electric power transmission methods, combined with unprecedented demands for electric power in the West, have resulted in large-scale development of some of these coals. In the past few years, announcements of coal mine openings and transportation plans in the Southwest have been filled with superlatives: The Navajo mine in northwest New Mexico is expected to be the largest mine in the country in the near future. The largest single coal agreement ever made provides for coal shipment from northeast Arizona to Nevada via the largest and longest coal-slurry pipeline ever used. An 1100-mile haul of coking coal from northern New Mexico to California by unit train began last year. It is the purpose of this report to evaluate the coal resources of the Rocky Mountain area, and to project their potential utilization. In projecting energy demand levels on a national basis, the Bureau of Mines has developed some rather complex techniques to cope with uncertainties. Using these same techniques, an estimate has been made of consumption of Mountain area coal in 1980. No attempt was made to estimate coal consumption beyond 1980, but new market potentials are discussed briefly. The present and potential coal-producing fields of the Rocky Mountain area are in six states comprising the Mountain Region - Arizona, Colorado, Montana, New Mexico, Utah, and Wyoming. Since approximately 19% of the coal produced in these fields is shipped to the Pacific Region (Washington, Oregon, Cali-

Jan 1, 1969

The opening session* was held in the hall of the Franklin Institute, on Tuesday evening, June 20th, President Holley in the chair. The President introduced Mr. Franklin B. Gowen, who addressed the Institute as follows: Mr. President and Gentlemen : It has been made my pleasant duty to welcome you to the city of Philadelphia, but in so doing I shrink, with some natural reluctance, from appearing before an audience so much better fitted than I am to cope with the subjects which are usually presented to your association, and I can assure you that no trembling neophyte, first venturing within the groves of the Academy, or walking, with sacred reverence, in the gardens of Plato, felt more natural dread at the consequence of his own temerity than I do in appearing before an audience composed of geutlenlen belonging to a scientific society of which I am but too sensible that until now I have been a member only in name. In olden times, upon entering a temple sacred to the worship of any deity, it was customary to lay some offering upon the altar, and, in following this custom, it will be my duty, before entering upon the more pleasant part of the task which is assigned me, to call your attention to a subject with which I have been somewhat familiar, and which is entirely within the scope of your investigations, in the belief that I may throw out some hints or some suggestions of a process that may be fully developed by some of you, and eventually lead to the introduction of that which may be of service to the human race. The satirist who described the philosopher whom he met, as engaged in the process of extracting sunbeams from cucumbers,

By Maxwell Adams

OLIVER C. RALSTON, Salt Lake City, Utah.-We are indebted to these two gentlemen for the work which they have done with the oils derived from sage brush. Their work should not be confused, however, as the work of Mr. Adams deals with steam-distilled oils and that of Mr. Clevenger with destructively distilled oil, largely. In other words, Mr. Adams' oil is probably the original essential oil that existed' in the brush before distillation while Mr. Clevenger's oil not only contained this essential oil but also some products of destructive distillation of the wood constituents. I had noticed the work of Mr. Adams on attempting to separate the various constituents in the oils of some of the Western conifers and had sent to him to ask if he could send me small samples of some of. these pure products. This he very kindly did, and with them included some samples of oil from the common sage brush, whose characteristics he has here described, as well as a sample of oil from the common "rabbit brush." Only the sage brush oil proved of much value for flotation, but it, was very powerful, and I so informed Mr. Adams. Even in amounts as small or smaller than 1/10 lb. per ton of ore, it gave very quick and positive flotation of many ores, with high-grade concentrates and good extractions. It proved to be especially desirable for the flotation of carbonates of lead and of copper which had received an artificial coating of sulphide by treatment with a solution of a soluble sulphide. I also received a sample of crude pyroligneous acid from sage brush prepared by Dr. W. C. Ebaugh, of Salt Lake City. It did not do very good work in flotation, but it is possible that by concentration of this product to obtain the residual tar a good flotation oil might result. This has not been done as yet and I am sorry to see that Mr. Clevenger has not done this. It might be that the dissolved tar, added to the settled tar, would make a total yield of flotation oil higher than the 4 per cent. which Mr. Clevenger feels is a safe estimate. The importance of this point will be seen in the following discussion of the possible costs of sage brush oils for flotation.

Jan 10, 1916

By G. A. Deitz, J. Halpren

The kinetics of dissolution of silver in cyanide solutions under oxygen pressure have been investigated over a wide range of conditions with a view to establishing the reactions involved and the factors which influence the rate. The results indicate that the rate is determined principally by the transport of reactants in solution to the silver surface. The thermodynamic features of the reaction with particular reference to the influence of pH and CN- are also discussed and summarized in the form of potential-pH diagrams. METALLIC silver is readily attacked and dissolved by cyanide solutions in the presence of oxygen. This reaction has long been recognized and extensively applied1 in the well-known cyanide process for the extraction of silver from its ores. While this process has been subjected in the past to a number of investigations2,3 both of a practical and fundamental nature, some features relating to the chemistry of the reactions involved, the role of oxygen, the nature of the rate-controlling step, and the effects of pH and certain reagents such as lime, are still not fully understood. It was felt that this situation justified a further investigation of the reaction, made with a view to obtaining a better understanding of its kinetics and mechanism. In the present investigation rate curves for the dissolution of silver were determined over an extensive range of carefully controlled reaction conditions. By carrying out the reactions in a pressure vessel, the partial pressure of oxygen, and hence its concentration, could be varied widely. The influence on the reaction of other variables including temperature, pH, and the concentrations of cyanide, peroxide, and other salts was also examined. The results of these kinetic studies are presented and discussed in this paper, together with a summary of available thermodynamic information relating to the possible reactions which can accompany the attack on silver by aqueous solutions of cyanide and oxygen. Chemistry and Thermodynamics of the Reaction The chemistry of the reactions of gold and silver with aqueous cyanide solutions has been the subject of several recent reviews.'." It has been proposed' that the following reaction occurs when silver dissolves in cyanide solutions in the presence of oxygen: 4Ag + 8CN- + 0, + 2H.0 -t 4Ag(CN); + 40H- [la] An equation of this form, for the corresponding dissolution of gold, was first suggested by Elsner." Bodlaender5 proposed a similar overall reaction, but suggested that it took place in two steps, 2Ag + 4CN- + O2 + 2H2O ? 2Ag(CN),- + 2OH- + H2O2 [2a] followed by 2Ag + 4CN- + H2O2? 2Ag(CN); + 20H- [3a] On the other hand, Janin- suggested that the dissolution of gold can occur with the liberation of hydrogen, rather than by reduction of oxygen. The corresponding equation for the dissolution of silver is 2Ag + 4CN- + 2H20 -t 2Ag(CN); + 20H + H2 [4a] All these reactions represent oxidation-reduction processes and may be resolved into the corresponding separate oxidation and reduction components. The oxidation step involves the formation of the argentocyanide ion and is the same for all the reactions, i.e., Ag + 2CN? Ag(CN)2 + e [51 However, reactions la, 2a, 3a, and 4a differ in the nature of the reduction steps which are, respectively, O2 + 2H2O + 4e ? 4OH- [lb] O2 + 2H2O + 2e ? H2O2 + 2OH- [2b] H2O2 + 2e ? 2OH- [3b] 2H2O + 2e? 20H- + H2 [4b]

Jan 1, 1954

By R. I. Jaffee, H. R. Ogden, D. J. Maykuth

Phase diagrams for the Ti-W and Ti-Ta systems were determined. The Ti-W system is characterized by a wide, two-phase region of ß plus tungsten which is derived from a peritectic reaction between the liquid and tungsten solid solutions. The ß field terminates in a eutectoid reaction between a titanium and tungsten terminal solid solution. Tantalum and ß titanium form a complete series of solid solutions. Other features of this system are the extensive a-ß field at low temperatures and an appreciable solubility of tantalum in a titanium. BOTH tungsten and tantalum were first thought to form ß-isomorphous systems with titanium as a result of early work' using powder-metallurgical techniques. Later work2 on arc-melted Ti-Ta alloys, made using a commercial titanium base, showed that, in the range of 0 to 10 pct, tantalum was soluble in ß titanium and that the a solubility extended to between 2 and 5 pct Ta at 790 °C. The present investigation covered the entire alloy range in both systems and was chiefly concerned with high-purity alloys at the titanium-rich end. The constitution of titanium-rich alloys made with a commercial titanium base was reported by Holla-day, Kura, and Jackson.3, 4 As will be shown in detail later, the early prediction of a isomorphism was true for the case of the Ti-Ta system, but not for the Ti-W system. The results of this investigation will be presented first. The experimental methods used are described in the Appendix. Ti-W System The entire Ti-W phase diagram is shown in Fig. 1. Details of the titanium-rich side are shown in Fig. 2. The chief features of the system are a ß eutectoid and a high-temperature peritectic between liquid and tungsten solid solution. Melting Range: Examination of cast structures of low and medium-tungsten-content ingots showed cored ß phase as the primary constituent. Fig. 3a illustrates a typical cast structure for alloys in the range of 20 to 30 pct W. From 30 to 72 pct W, coring was very severe. Alloys containing 72 through 88 pct W, however, showed definite evidence of a peritectic reaction between the liquid and a terminal solid solution of titanium in tungsten. Fig. 3b shows the cast structure for an 80 pct W alloy. A 95 pct W alloy, shown in Fig. 4, consisted primarily of primary tungsten solid solution plus a small quantity of ß probably rejected during cooling. Incipient-melting experiments located the peritectic temperature between 1850" and 1900°C and indicated that the reacting phases are liquid containing about 25 pct W and tungsten terminal solid solution containing about 8 pct Ti. Figs. 5 and 6

Jan 1, 1954

By Ralph Hultgren, David W. Mitchell

MAGNESIUM alloys usually are superheated before casting in order to ensure fineness of grain. Superheat temperatures in common use range from 1600° to 1700°F while the casting temperature, which depends upon the mold shape, is usually 200° to 300°F lower. The process of superheating requires considerable time and seriously shortens the life of the iron pots used. Recently it has been reported' that if acetylene, carbon dioxide or natural gas is bubbled through molten electrolytic A.S.T.M. No. 4 alloy at 1400°F. for 5 min., grain refinement equivalent to that of superheating will take place. Addition of certain solids such as graphite or aluminum carbide accomplishes the same results.2 As will be shown in this paper, it is possible to achieve grain refinement in magnesium casting alloys at low temperatures by mechanical stirring of the molten metal for a short time. This process was developed in the course of research work, supervised by the War Metallurgy Committee under the "Restricted" Project NRC-550, for the Office of Production Research and Development of the War Production Board. This paper, based on that work, has been released for publication by the O.P.R.D. MATERIALS AND METHODS The alloys studied were the most common American sand-casting alloys designated as No. 4 and No. 17 by the American Society for Testing Materials. The magnesium used in these alloys was of both carbothermic3 and electrolytic4 origin. Chemical analyses supplied by the producers are shown in Table I. Each heat consisted of approximately 5 lb. of alloy melted in a Tercod crucible. It was refined by fluxing with Permanente No. 7* refining flux at 1300° to 1350°F. After cooling to 1200' to 1250°F., portions of approximately one pound each were ladled into iron crucibles contained in an electric furnace at about 1250°F. The molten metal was covered with Permanente No. 21† covering flux and then heated to the temperature to be investigated. Normally each of the four portions was given a different treatment. In a typical case one portion was stirred vigorously for 5 min., acetylene gas was passed through a second portion for 5 min., a third portion was superheated to 1600°F for 15 min., then cooled to casting temperature, and the fourth was held for 5 min. at the temperature of stirring or gassing without other treatment. Each portion was then cast into one-inch diameter cylinders in three "nonturbulent" molds of identical shape. One mold was made of cast iron and the other two of baked sand. The cast-iron mold and one of the baked sand molds were heated to 360°F., the other baked sand mold was at room temperature. The freezing times in these molds were

Jan 1, 1945

By Ralph Hultgren, David W. Mitchell

Magnesium alloys usually are superheated before casting in order to ensure fineness of grain. Superheat temperatures in common use range from 1600" to r 7o0°F.; the casting temperature, which depends upon the mold shape, is usually 200° to 300°F. lower. The process of superhcating requires considerable time and seriously shortens the life of the iron pots used. Recently it has been reported1 that if acetylene, carbon dioxide or natural gas is bubbled through molten electrolytic A.S.T.M. No. 4 alloy at 1400°F. for 5 min., grain refinement equivalent to that of superheating will take place. Addition of certain solids such as graphite or aluminum carbide accomplishes the same results? As will be shown in this paper, it is possible to achieve grain refinement in magnesium casting alloys at low temperatures by mechanical stirring of the molten metal for a short time. This process was developed in the course of research work, supervised by the War Metallurgy Committee under the "Restricted' project NRC-550, for the Office of Production Research and Development of the War Production Board. This paper, based on that work, has been released for publication by the O.P.R.D. Materials and Methods The alloys studied were the most common American sand-casting alloys designated as No. 4 and No. 17 by the American Society for Testing Materials. The magnesiun used in these alloys was of both carbothermic3 and electrolytic' origin. Chemical analyses supplied by the producers are shown in Table I. Each heat consisted of approximately 5 lb. of alloy melted in a Tercod crucible. It was refined by fluxing with Permanente No. 7* refining flux at 1300° to 1350°F. After cooling to 1200° to 1250°F., portions of approximately one pound each, were ladled into iron crucibles contained in an electric furnace at about 1250°F. The molten metal was covered with Permanente No. 21 † covering flux and then heated to the temperature to be investigated. Normally each of the four portions was given a different treatment. In a typical case one portion was stirred vigorously for 5 min., acetylene gas was passed through a second portion for 5 min., a third portion was superheated to 1600°F. for 15 min., then . cooled to casting temperature, and the fourth was held for 5 min. at the temperature of stirring or gassing without other treatment. Each portion was then cast into one-inch diameter cylinders in three "nonturbulent" molds of identical shape. One mold was made of cast iron and the other two of baked sand. The cast-iron mold and one of the baked sand molds were heated to 360°F., the other baked sand mold was at room temperature. The freezing times in these molds were

Jan 1, 1945