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By H. C. Schultz

CERTAIN local conditions were known to govern in large measure the successful adaptation of liquid-oxygen explosives to the large-scale blasting at Chuquicamata. The wide variation in hardness of the rock at this mine makes necessary the use of several types of explosives. A locally manufactured, relatively cheap black powder is used in blasting the softer waste and capping material, where a thorough displacement, breaks the ground sufficiently. Before the introduction of L. 0. X., an ammonia dynamite of about 65 per cent. strength was being used exclusively in the harder underlying orebody, where a strong disruptive as well as a displacement effect is required for breaking the ore. The L. 0. X., as developed for quarry work in the United States, has a practically pure carbon cartridge material, and the explosive has an extremely high rate of detonation, which should therefore cause it to usefully develop its full disruptive effect in hard ground. The individual blasts at Chuquicamata are large, black-powder shots which dislodge masses of rock averaging 250,000 tons each, and dynamite shots which dislodge masses averaging 80,000 tons each. It was desirable, therefore, to attempt to displace with L. 0. X. the faster, higher-cost ammonia dynamite used in the smaller blasts. It was not considered practical to attempt to displace the low-cost black powder with L. 0. X., as estimated costs showed no probable saving if this were accomplished. Since it was desirable to continue shooting relatively large blasts for effective operation, it was recognized that larger storage facilities than had been in use would be needed for the liquid oxygen. Because of the difficulty of transporting and discharging large storage containers of efficient design, the better plan appeared to be storage and discharge of the liquid at the place of manufacture, and transportation of the filled soaking boxes to the blast.

Jan 1, 1928

By M. D. Hassiallis

The claim is made in a number of patents1'2'3'4 that some compounds of the class known as aryl sulphides have collector properties. One of these patents generalizes the claim to include all aryl sulphides, whose generic formula is R-S2-R' (where x = 1,2, . . . ), with the restriction that if the aromatic radicals R, R' contain substituent groups these groups may not contain nitrogen or oxygen. Moses, Hess, and Perkins cite as evidence for their claims the results of flotation tests on Anaconda and Miami copper ores using diphenyl sulphide, ditolyl disulphide and dinapthyl disul-phide as collectors. The use of alkyl sulphides as collectors has also been reported5 with the conclusion that the alkyl sulphides are better collectors than the corresponding aryl sulphides. The experimental work cited appears to confirm this contention. In order to test these claims with respect to diphenyl sulphide, a sample, purchased from the Eastman Kodak Co., was tested against Anaconda ore. The procedure followed. was that of Moses, Hess, and Perkins. A sample of ore weighing 500 • grams was placed in a laboratory ball mill. To this was added 220 grams of water, 0.06 grams of commercial diphenyl sulphide (1/4 lb. per ton of ore), and 0.8 grams of lime (3 lb. per ton of ore). The material was ground until 93 per cent passed a 65-mesh screen. This pulp was diluted to 16 per cent solids. A sample of the diluted pulp was placed in a Minerals Separation type of laboratory flotation cell. After a a-min. agitation period, pine oil was added and the froth collected for a period of 15 min. This test recovered 68 per cent of the copper, with a ratio of concentration of 6.8:I. The tailing assay was 0.3 per cent Cu. Moses, Hess and Perkins attained a recovery of 75 per cent, with a ratio concentration of I2:I. Although these results do not compare too well with those of Moses, Hess and Perkins, subsequent tests showed an improvement, as judged by vanning of the tails. It is concluded, therefore, that the patent results are confirmed. Contact-angle Tests In order to study the response of the various minerals, found in Anaconda ore, to commercial diphenyl sulphide, some contact-angle tests were made. Polished particles of bornite, chalcodte, chalco-pyrite, pyrite and quartz were conditioned for 15 min. in a suspension of diphenyl sulphide in water. The concentration of this suspension was 0.284 grams per liter, this being the concentration of this reagent in the ball mill. The conditioned particles were rinsed with water (not rubbed with filter paper or boiled linen) and then tested against an air bubble in the bubble machine, with the following results: born-

Jan 1, 1943

By M. D. Hassialis

THE claim is made in a number of patents1,2,3,4 that some compounds of the class known as aryl sulphides have collector properties. One of these patents generalizes the claim to include all aryl sulphides, whose generic formula is R-S¬R[=]-R’ (where x = r,2, . . . ), with the restriction that if the aromatic radicals R, R' contain substituent groups these groups may not contain nitrogen or oxygen. Moses, Hess, and Perkins cite as evidence for their claims the results of flotation tests on Anaconda and Miami copper ores using Biphenyl sulphide, ditolyl disulphide and dinapthyl disulphide as collectors. The use of alkyl sulphides as collectors has also been reported5 with the conclusion that the alkyl sulphides are better collectors than the corresponding aryl sulphides. The experimental work cited appears to confirm this contention. In order to test these claims with respect to diphenyl sulphide, a sample, purchased from the Eastman Kodak Co., was tested against Anaconda ore. The procedure followed was that of Moses, Hess, and Perkins. A sample of ore weighing 500 grams was placed in a laboratory ball mill. To this was added 220 grams of water, 0.06 grams of commercial diphenyl sulphide (1/4 lb. per ton of ore), and 0.8 grams of lime (3 lb. per ton of ore). The material was ground until 93 per cent passed a 65mesh screen. This pulp was diluted to 16 per cent solids. A sample of the diluted pulp was placed in a Minerals Separation type of laboratory flotation cell. After a 2-min. agitation period, pine oil was added and the froth collected for a period of 15 min. This test recovered 68 per cent of the copper, with a ratio of concentration of 6.8: 1. The tailing assay was 0.3 per cent Cu. Moses, Hess and Perkins attained a recovery of 75 per cent, with a ratio concentration of 12: 1. Although these results do not compare too well with those of Moses, Hess and Perkins, subsequent tests showed an improvement, as judged by vanning of the tails. It is concluded, therefore, that the patent results are confirmed. CONTACT-ANGLE TESTS In order to study the response of the various minerals, found in Anaconda ore, to commercial diphenyl sulphide, some contact-angle tests were made. Polished particles of bornite, chalcocite, chalcopyrite, pyrite and quartz were conditioned for 15 min. in a suspension of diphenyl sulphide in water. The concentration of this suspension was 0.284 grams per liter, this being the concentration of this reagent in the ball mill. The conditioned particles were rinsed with water (not rubbed with filter paper or boiled linen) and then tested against an air bubble in the bubble machine, with the following results: born-

Jan 1, 1943

By M. D. Hassiallis

The claim is made in a number of patents1'2'3'4 that some compounds of the class known as aryl sulphides have collector properties. One of these patents generalizes the claim to include all aryl sulphides, whose generic formula is R-S2-R' (where x = 1,2, . . . ), with the restriction that if the aromatic radicals R, R' contain substituent groups these groups may not contain nitrogen or oxygen. Moses, Hess, and Perkins cite as evidence for their claims the results of flotation tests on Anaconda and Miami copper ores using diphenyl sulphide, ditolyl disulphide and dinapthyl disul-phide as collectors. The use of alkyl sulphides as collectors has also been reported5 with the conclusion that the alkyl sulphides are better collectors than the corresponding aryl sulphides. The experimental work cited appears to confirm this contention. In order to test these claims with respect to diphenyl sulphide, a sample, purchased from the Eastman Kodak Co., was tested against Anaconda ore. The procedure followed. was that of Moses, Hess, and Perkins. A sample of ore weighing 500 • grams was placed in a laboratory ball mill. To this was added 220 grams of water, 0.06 grams of commercial diphenyl sulphide (1/4 lb. per ton of ore), and 0.8 grams of lime (3 lb. per ton of ore). The material was ground until 93 per cent passed a 65-mesh screen. This pulp was diluted to 16 per cent solids. A sample of the diluted pulp was placed in a Minerals Separation type of laboratory flotation cell. After a a-min. agitation period, pine oil was added and the froth collected for a period of 15 min. This test recovered 68 per cent of the copper, with a ratio of concentration of 6.8:I. The tailing assay was 0.3 per cent Cu. Moses, Hess and Perkins attained a recovery of 75 per cent, with a ratio concentration of I2:I. Although these results do not compare too well with those of Moses, Hess and Perkins, subsequent tests showed an improvement, as judged by vanning of the tails. It is concluded, therefore, that the patent results are confirmed. Contact-angle Tests In order to study the response of the various minerals, found in Anaconda ore, to commercial diphenyl sulphide, some contact-angle tests were made. Polished particles of bornite, chalcodte, chalco-pyrite, pyrite and quartz were conditioned for 15 min. in a suspension of diphenyl sulphide in water. The concentration of this suspension was 0.284 grams per liter, this being the concentration of this reagent in the ball mill. The conditioned particles were rinsed with water (not rubbed with filter paper or boiled linen) and then tested against an air bubble in the bubble machine, with the following results: born-

Jan 1, 1943

By G. T. Brookman, P. B. Katz, D. K. Martin, J. A. Ripp

With the increasing emphasis on using American fossil fuel resources, more facilities are evaluating coal conversion. In addition, those facilities now using coal are considering better coal storage procedures to minimize negative environmental impacts. For example, rainfall and snowmelt on a coal pile produce a drainage stream high in acidity, suspended and dissolved solids, iron, sulfate, and trace metals. Usually, the characteristics of the runoff stream do not allow for direct discharge to streams and lakes. Detention in a holding pond and pH adjustment are traditional methods of treating coal pile runoff before discharge. Historically, this treatment methodology has been performed inefficiently without a good data base to assess how much runoff treatment is needed to meet effluent guidelines. A model was developed to simulate runoff volume and pollutant loadings under different rainfall conditions. This model will be used to size and design treatment works for coal pile drainage. The Ohio State University (OSU) version of the Stanford watershed model was selected as the base model. The OSU model simulates overland runoff in a rural area. It includes factors such as soil moisture, depression storage, infiltration, and flow to a ground water reservoir. TRC also used the OSU co-model for acid production in coal refuse piles as the basis for qualitative modeling work. A number of modifications were made to the OSU models to make them applicable to coal storage piles. The physical/chemical reactions included in the models are described in more detail in the project report. In addition, the models were altered so that a standard NOAA magnetic tape of historical meteorological data can be used as data input instead of requiring the user to create a data file. The resulting TRC coal pile drainage model is actually two models - a quantitative model, termed H2OTRC, and a qualitative model, TRCCOAL.

Jan 1, 1984

By E. A. Sondreal, F. I. Honea

This paper summarizes coal and ash properties and pilot-plant results for 14 key lignite seams in the Gulf Province, as well as discusses operating problems encountered by the four Texas power plants burning Gulf Province lignite. Some consideration is given to the design of future power plants.

Jan 1, 1982

In the 100' years since AIME was founded in 1871, the Institute has issued a great many publications in a variety of forms: periodicals, Transactions volumes, and special volumes or books. The following is a brief history of AIME publishing with some suggestions for proper referencing. TRANSACTIONS AIME Transactions volumes have been numbered consecutively since No. 1 was issued in 1873, including papers for the period 1871-1873. One or more volumes have been issued each year and may be divided into three general time periods: General Volumes (1873-1927), Volumes classified by subject matter (1928-1949), and the present practice, begun in 1949, of issuing three volumes per year, one each in the fields of mining engineering, metallurgy, and petroleum technology. The broad divisions of subject matter in each of these volumes correspond to the technical areas of the three constituent societies of AIME. AIME's Technical Publications, usually designated by TP number's (until the change in numbering system by the Society of Mining Engineers in 1958), may, with some exceptions, be referenced to an AIME Transactions volume. Reference to a specific volume, rather than paper number, is the preferred reference, since the volumes are the form of publication most commonly available in libraries. In many cases, over the years, the Technical Publications may also have been available in some other form, either as separates or in a periodical. General. Volumes (Vols. 1-78, 1873-1927): Until 1927 all papers eligible for Transactions were published in general volumes with no systematic attempt made to segregate the material on the basis of the technological fields to which the papers related.. One volume per year was issued from 1873 until 1912; from 1912 until 1927 from two to four volumes were issued annually. In addition to the Transactions papers, these volumes carried some of the proceedings of the business meetings of AIMS. Subject Volumes. (Vols. 79-183; 1928-1949): The material for these volumes was segregated according to subject matter, and up. to seven volumes were issued a year. In the latter part of the period, from 1934 on, there was one volume each' year for the Petroleum, Institute of Metals, and Iron and Steel Divisions and-the remaining papers were grouped in various ways and is sued whenever sufficient numbers of papers had accumulated: The subject volumes containing mining engineering papers are listed in Table 1. The volumes for the period, 1936-1949 are included in this Cumulative Index. Each of the Transactions volumes carries on the binding the year of publication; this date does not give an indication of when the papers included were originally presented at meetings. The contents of the volumes usually list the meetings at which. the papers were presented. Not all papers from a given meeting necessarily are in one Transactions volume. Some of the earlier volumes do not have a number on the binding or within the volume. In 1934 numbers" were assigned to all Transactions volumes, commencing with the 1871-1873 volume as No. 1. Many of the papers published [ ]

Jan 1, 1972

This excellent, concise paper by Dr. Iwasaki on the principles of selective flocculation for iron ores discusses many of the principles and problems which have occurred in our bench and pilot plant test-work. The use of sodium tripolyphosphate in combination with sodium silicate as a dispersant is very effective. However, this may cause a problem with the environmental groups as phosphorous is a nutrient. We have also established that the lower the Ca level in the pulp solutions the greater the dispersion. We have found that ores from the same geological strata, having the same general mineralogy and iron content will sometimes have widely different degrees of dispersion. There was-no difference in the gross mineralogy but the solubility of the Ca and SO ions was much less in the ores most easily dispersed. Research efforts should be directed towards a more practical means which would more easily enable one to predict the amount of dispersant required for the various ores. With regard to water quality we have found that waters having higher contents of SO4 and C1 ions hinder dispersion. This could be a method of controlling too much dispersion by the addition of sulfate or chloride ions. This would require further investigation. We have had no trouble with agitation speeds of up to 925 rpm in conditioning starch with the dispersed pulp prior to selective flocculation. We have found about 0.3Lb/LT of starch to be sufficient for selective flocculation on our ores. The increasing of the starch to 1.25Lb/LT has had no effect on the metallurgy of the selective floccula-

Jan 1, 1979

By C. M. Wayman, M. A. Gedwill, C. J. Altstetter

Cobalt Whiskers were grown by the hydrogen reduction of CoBr,. The fcc = hcp martensitic trans-formation in these whiskers was studied using X-ray and metallographic techniques. Present theories of the fee + hcp martensitic transformation were ex-amined in the light of the present findings Experimental evidence for slip as a part of the transformation mechanism is presented. In the bulk form cobalt is known to undergo a martensitic transformation1 from an hcp to an fcc structure upon heating above about 430°C. Upon cooling, the reverse transformation starts at about 400°C, but does not go to completion except in single crystalline or coarse-grained samples, or upon plastic deformation. The transformation may be thought of as the shearing of close-packed atomic planes in such a way as to change the stacking sequence from ABCABC to ABABAB with a contraction normal to the shearing planes and an expansion in the planes,2 producing a c/a ratio slightly less than ideal. This restacking to give {0001) and (112) 11 (1010) can be accomplished by the passage of a shockfey partial dislocation over every other (111)f plane resulting in a theoretical shear of 19.47 deg. To date there has been no completely satisfactory explanation of how the partial dislocations are produced on the close-packed planes or propagated from plane to plane to give the correct stacking sequence. The object of the present research was to study some of the characteristics of the fcc to hcp transformation in geometrically simple single crystals. It was felt that whiskers of cobalt grown by halide reduction would be ideal specimens with which to study the transformation, because whiskers have the following desirable features: 1) are easily grown as fcc single crystals; 2) exhibit relatively simple geometries; 3) have comparatively low dislocation densities;

Jan 1, 1964

By F. R. Morral, E. P. Miller

Hot-dipped heat-treated zinc coatings on sheet steel were examined with X-rays. The phases identified were compared with those listed in the modern literature 01 the zinc-iron system. The zeta (FeZn13) phase is shown to correspond to the phase found by Schueler (1925) in heat-treated zinc coatings. An investigation was undertaken to determine the phases present in hot-dipped heat-treated zinc coatings on steel sheets and wire. This kind of coating on wire was studied some years ago by Schuelerl by microscopic and chemical methods. He reported a new phase, FeZn10. Later, Clark and Stillwell,2 using X-ray crystal analysis, identified a new phase in ordinary galva. nized wire, which was assumed to be the FeZn10 phase. Since the extensive review of the iron-zinc alloys presented a few years ago,3 much new work has been published, some of which5-l6 was too late to be included in the recent edition (1939) of the American Society for Metals' Handbook.4 Figs. 1 and 2 are reproductions of the latest iron-zinc diagram proposed by Schramml1 as a result of his investigations by microscopic, thermal, magnetic susceptibility and X-ray methods. Table 1 summarizes all the known published X-ray data of the phases Present. The solubility of iron in zinc has been determined by x-ray methods.10 In the same manner the homogeneity range of the P phase was studiedlo using the principle that the parameter of an intermetallic compound changes while the concentration of One of the constituents changes. Schramm10 has found some 80 alpha lines in X-ray powder photograms of phase d1, and from these he believes that this phase is related to the P phase. Previous investi-

Jan 1, 1941

By E. P. Miller, F. R. Morral

Hot-dipped heat-treated zinc coatings on sheet steel were examined with X-rays. The phases identified were compared with those listed in the modern literature 01 the zinc-iron system. The zeta (FeZn13) phase is shown to correspond to the phase found by Schueler (1925) in heat-treated zinc coatings. An investigation was undertaken to determine the phases present in hot-dipped heat-treated zinc coatings on steel sheets and wire. This kind of coating on wire was studied some years ago by Schuelerl by microscopic and chemical methods. He reported a new phase, FeZn10. Later, Clark and Stillwell,2 using X-ray crystal analysis, identified a new phase in ordinary galva. nized wire, which was assumed to be the FeZn10 phase. Since the extensive review of the iron-zinc alloys presented a few years ago,3 much new work has been published, some of which5-l6 was too late to be included in the recent edition (1939) of the American Society for Metals' Handbook.4 Figs. 1 and 2 are reproductions of the latest iron-zinc diagram proposed by Schramml1 as a result of his investigations by microscopic, thermal, magnetic susceptibility and X-ray methods. Table 1 summarizes all the known published X-ray data of the phases Present. The solubility of iron in zinc has been determined by x-ray methods.10 In the same manner the homogeneity range of the P phase was studiedlo using the principle that the parameter of an intermetallic compound changes while the concentration of One of the constituents changes. Schramm10 has found some 80 alpha lines in X-ray powder photograms of phase d1, and from these he believes that this phase is related to the P phase. Previous investi-

Jan 1, 1941

By John Mark Patek

Knowledge of the relative floatability of silicate minerals is increasing in importance as flotation is being applied to the concentration of nonsulfides. Many silicates are in themselves commercial products amenable to concentration by flotation. Moreover, the selective flotation of other nonsulfide minerals, such as cassiterite, depends largely upon the floatability of associated gangue silicates. Differences in floatability existing between the various silicates have not- been sufficiently appreciated; for example, the feldspars that differ greatly in floatability have generally been merely treated as "feldspar." It was the purpose of the work described in this paper to determine by experiment the differences in floatability between silicates; to investigate the causes for such differences, and to discover a means of predetermining approximate floatability without the necessity of experimentation. Determining Floatability The relative floatability of 20 silicates so selected as to represent all of the more common silicate types1 was obtained by flotation tests enumerated in Table 1. The mineral to be floated was crushed dry on a steel plate, and screened repeatedly during crushing through an 80-mesh screen in order to produce a sand with all grains as close to 80 mesh as possible. The sand was placed in dilute (6N) hydrochloric acid until free of soluble foreign material, and then washed with tap water about ten times in order to remove both acid and fines. The resultant product, which averaged 82 per cent plus 200 mesh, was floated in 50-gram charges in a 50-gram Denver celluloid flotation machine with 0.008 gram of terpineol, and from 0.01 to 0.05 gram of oleic acid in a solution acidified with sulfuric acid. The degree of separation of one mineral from another was determined by counting under a nlicroscope the grains of each mineral, both in the concentrate and in the tailings, and comparing their relative abundance in each. Unless the comparison showed a decided difference in amount,

Jan 1, 1935

By George T. Bator

If confronted with the problem of pumping a mixture of slime-free sand, gravel and boulders up to six in. in diameter, at the rate of 175 tons per hr in one single-stage pump against a static head of 90 ft and a total head of 140 ft, of which 20 is on the suction side, an engineer might be forgiven for backing away from the job, especially if he were also told that the pump wearing parts must have a minimum hardness of 550 Brinell for the sake of abrasion resistance.

Jan 1, 1950

INCREASING realization that pouring and ingot-mold practices involve many factors of fundamental importance to ingot quality and general steel-mill operations has caused these phases of steelmaking to become major concerns of operators and metallurgists engaged in control of quality and costs. Methods of pouring steel from the ladle into the ingot molds have some direct effects on ingot quality. The mold itself governs solidification and dimensions of the ingot and in so doing exerts some very tangible influences not only on ingot quality but also on product yields and general steel-mill processing. In addition, practices are employed' in the handling of molds during daily open-hearth operations that are important to quality and production costs. Therefore, pouring and mold practices must be considered highly specialized and important steps in steel-mill operations. MOLD DESIGN Mold design is difficult to discuss in a precise manner because it varies greatly throughout the industry, both in theoretical concepts and practical application, and few well developed data are available. Most ingot molds are designed to meet conditions peculiar to a given plant wherein quality standards are dictated by end-use requirements, which may differ considerably, even for the same grade of steel. The mold designer must also consider the equipment available to process ingots and the product obtained from them. Such equipment, used for stripping, heating, blooming and finishing operations, is seldom, if ever, exactly the same in any two steel plants. Thus, pronounced contrasts in mold designs can be expected to continue, even among plants making strictly comparable types of product, particularly because some producers are just beginning to realize the benefits possible from specialized designs. Certain fundamentals are used in mold design but even these

Jan 1, 1951

By B. C. Raynes

IN the early part of 1952, under the auspices of the U. S. Atomic Energy Commission, Horizons Inc. undertook an investigation dealing with the preparation of high purity thorium metal in order to develop an economically competitive production process for this metal based on a recovery of the metal by a fused salt electrolysis, since a survey of the literature of thorium chemistry indicated that electrolytic methods had not received much attention, despite the consideration that electrochemical production methods often offer attractive commercial potentialities. Thorium metal has been prepared by methods which fall into four general categories: 1) reduction of halides or double halides; 2) reduction of the oxide; 3) thermal decomposition of halides; and 4) electrolytic methods. Some of the important results obtained by various investigators since about 1900 in recorded attempts to prepare pure thorium metal are summarized in Table I. A bibliography of pertinent literature is included in this paper. Thorium is strongly electropositive and possesses a great affinity for oxygen and nitrogen. As a result the prospects for the production of high purity thorium from aqueous media or oxygen bearing compounds are remote. The most promising and profitable area of investigation for production of thorium metal lies in fused salt electrolysis. Thorium has been produced previously by this technique from halide salts in fused alkali chloride eutectic mixtures. Until recently, however, the lack of known large uses for thorium has inhibited the investigation of these methods. The basic problem in an investigation into fused salt production methods for thorium is to develop a suitable fused salt system for the economic preparation of thorium. The first portion of the work in these laboratories was a small scale investigation of the electrolysis of potassium thorium fluoride, KThF5, under a variety of conditions. High purity thorium was prepared in this manner, but the process did not appear to offer the simplest and most attractive continuous commercial operation. The work reported here relates to an all-chloride system employing thorium chloride as the cell feed. ThCL4 was produced as an anhydrous material stabilized in molten sodium chloride. This product, further diluted in NaCl, was subjected to electrolysis. The electrolytic process has been studied in cells capable of holding up to 50 lb total salt charge. Ductile, pure thorium metal has been reproducibly obtained in this operation. Considerable experimentation was carried out in the preparation of ThCL as a cell feed free from moisture, oxides, and other impurities. Thorium was cathodically deposited as a coarsely crystalline powder interspersed with residual bath salts. Aqueous procedures for separating and recovering the metal were developed. The thorium metal powder obtained has been evaluated with respect to its hardness, chemical purity, and certain other physical properties. Preparation of ThC1,—Thorium chloride, and the chlorides of some other metals (aluminum, beryllium, tantalum, zirconium, etc.) cannot be obtained from aqueous solution by direct heating and evaporation. Evaporation and heating of a solution of thorium chloride yields a hydrated salt or partially hydrated salt, and finally Tho,. Anhydrous thorium chloride is obtained by forming a hydrated ammonium chloride complex salt in acidified water solution, dehydrating this compound, and finally decomposing the double salt and subliming the ammonium chloride component. Various methods for the preparation of anhydrous thorium chloride, in accordance with this concept, were investigated as indicated in Table I1 from hydrated thorium chloride (ThCl, . 3H2O), and from thorium oxycarbonate (ThOCO,). In the method found most satisfactory for this work, thorium oxycarbonate was dissolved in an excess of concentrated HC1 to give a clear yellow solution. At least 2 mol NH,Cl were added to the solution per mol of contained thorium. Ammonium thorium chloride hydrate was crystallized from solution by cooling and saturation with HC1. The resultant complex, (NH,Cl),ThCl;xH,O, was dehydrated by evaporation at 130° to 150°C and thoroughly dried at about 250°C. The dried ammanium thorium chloride was then mixed with sodium chloride in proportions to form NaThCL or to produce a ThCL4-NaCl mixture with a given thorium content. The ammonium chloride was sublimed off at temperatures above 500°C in an inert atmosphere furnace to give an anhydrous chloride source electrolyte, essentially free of Tho, and of NKC1.

Jan 1, 1958

[ ] TUNNELS TO BINS. Originally designed for tunnel work, the strong lightweight liner plates used to construct this 30-ft diameter, 31-ft high, aggregate storage bin have several advantages. Bins and conveyor to tunnels can be quickly erected in any season, for permanent service, or to be salvaged and reused. Armco Steel Corp. (16) ROLLER CHAIN: Engineering Data Book No. 2457 published by Link-Belt Co. is a comprehensive 148-page volume on roller chain and its application. Detailed engineering information covers installation, maintenance and lubrication of chains for drives, conveyors, and sprocket wheels. The book covers selection of drives to meet both standard and special installations. (17) LABORATORIES: The Fisher Scientific Co's. line of 21 basic units of standardized steel laboratory furniture is described in catalog no. 25. The Unitized line was designed to combine the advantages of custom installation with the convenience of selection, delivery and continued flexibility that goes with ready-made units. (18) PUMPS: Two similar, but functionally different types of vertical centrifugal wet-pit pumps; a heavy duty bilge pump for handling solids-free liquids and drainage; and a screenless sewage ejector, constructed to handle sewage and solids carrying liquid; are illustrated in a bulletin from Yeomans Bros. Co.

Jan 1, 1952

INCREASING realization that pouring and ingot-mold practices involve many factors of fundamental importance to ingot quality and general steel-mill operations has caused these phases of steelmaking to become major concerns of operators and metallurgists engaged in control of quality and costs. Methods of pouring steel from the ladle into the ingot molds have some direct effects on ingot quality. The mold itself governs solidification and dimensions of the ingot and in so doing exerts some very tangible influences not only on ingot quality but also on product yields and general steel-mill processing. In addition, practices are employed in the handling of molds during daily open-hearth operations that are important to quality and production costs. Therefore, pouring and mold practices must be considered highly specialized and important steps in steel-mill operations. MOLD DESIGN Mold design is difficult to discuss in a precise manner because it varies greatly throughout the industry, both in theoretical concepts and practical application, and few well developed data are available. Most ingot molds are designed to meet conditions peculiar to a given plant wherein quality standards are dictated by end-use requirements, which may differ considerably even for the same grade of steel. The mold designer must also consider the equipment available to process ingots and the product obtained from them. Such equipment, used for stripping, heating, blooming and finishing operations, is seldom, if ever, exactly the same in any two steel plants. Thus, pronounced contrasts in mold designs can be expected to continue, even among plants making strictly comparable types of product, particularly because some producers are just beginning to realize the benefits possible from specialized designs. Certain fundamentals are used in mold design but even these

Jan 1, 1964

By Alden B. Greninger, Alexander R. Troiano

The crystallographic mechanism for the austenite-to-martensite trensformation has been deduced from the results of the following new experimental determinations: (I) the accurate evaluation of the lattice relationship between austenite and individual crystals of martensite—and thus the relationship between the martensite lattice and the martensite plate, and (2) the measurement and analysis of the change in positions that a volume of austenite unclergoes when it transforms into a crystal of martensite. For the latter study, a new tool was developed, the stereographic analysis of shear. Lattice relationship.—Thirty-five separate 50-gram melts of an alloy containing about 22 per cent nickel and 0.8 per cent carbon were prepared in a high-vacuum furnace. This alloy is all-austenite at room temperature; grain size was about I cm. Specimens of the alloy were cooled to about — 70°C. to form a few martensite crystals, and suitable specimens were ground and polished on a surface parallel to a single martensite plate, exposing the martensite crystal for an area of 1 mm. or more. Four martensite cystals from four diffierent ingots were prepared in this manner; the largest crystal of this group is illuslratecl in Fig. I. Back-reflection Laue patterns were obtained from martensite crystals (and the matrix austenite) both before and after tempering. The locations of the basal-plane pole of martensite was checked by means of oscillating crystal X-ray patterns. All four crystals studied yielded the same solution ( ± 0.5°), and these relationships are expressed in gnomonic projection in Fig. 3.* The narrow dark-etching bands often visible in martensite "needles" were found to be parallel to (112) and thus are undoubtedly twin bands in the martensite crystal.

Jan 1, 1941

By Alden B. Greninger, Alexander R. Troiano

THE crystallographic mechanism for the austenite-to-martensite transformation has been deduced from the results of the following new experimental determinations: (I) the accurate evaluation of the lattice relationship between austenite and individual crystals of martensite-and thus the relationship between the martensite lattice and the martensite plate, and (2) the measurement and analysis of the change in positions that a volume of austenite undergoes when it transforms into a crystal of martensite. For the latter study, a new tool was developed, the stereographic analysis of shear. Lattice relationship.-Thirty-five separate 50-gram melts of an alloy containing about 22 per cent nickel and 0.8 per cent carbon were prepared in a high-vacuum furnace. This alloy is all-austenite at room temperature; grain size was about I cm. Specimens of the alloy were cooled to about -70°C. to form a few martensite crystals, and suitable specimens were ground and polished on a surface parallel to a single martensite plate, exposing the martensite crystal for an area of I mm. or more. Four martensite cystals from four different ingots were prepared in this manner; the largest crystal of this group is illustrated in Fig. I. Back-reflection Lane patterns were obtained from martensite [ ] crystals (and the matrix austenite) both before and after tempering. The locations of the basal-plane pole of martensite was checked by means of oscillating crystal X-ray patterns. All four crystals studied yielded the same solution (±0.5°), and these relationships are expressed in gnomonic projection in Fig. 3.* The narrow dark-etching bands often visible in martensite "needles" were found to be parallel to {112} and thus are undoubtedly twin bands in the martensite crystal.

Jan 1, 1941

By Alden B. Greninger, Alexander R. Troiano

The crystallographic mechanism for the austenite-to-martensite trensformation has been deduced from the results of the following new experimental determinations: (I) the accurate evaluation of the lattice relationship between austenite and individual crystals of martensite—and thus the relationship between the martensite lattice and the martensite plate, and (2) the measurement and analysis of the change in positions that a volume of austenite unclergoes when it transforms into a crystal of martensite. For the latter study, a new tool was developed, the stereographic analysis of shear. Lattice relationship.—Thirty-five separate 50-gram melts of an alloy containing about 22 per cent nickel and 0.8 per cent carbon were prepared in a high-vacuum furnace. This alloy is all-austenite at room temperature; grain size was about I cm. Specimens of the alloy were cooled to about — 70°C. to form a few martensite crystals, and suitable specimens were ground and polished on a surface parallel to a single martensite plate, exposing the martensite crystal for an area of 1 mm. or more. Four martensite cystals from four diffierent ingots were prepared in this manner; the largest crystal of this group is illuslratecl in Fig. I. Back-reflection Laue patterns were obtained from martensite crystals (and the matrix austenite) both before and after tempering. The locations of the basal-plane pole of martensite was checked by means of oscillating crystal X-ray patterns. All four crystals studied yielded the same solution ( ± 0.5°), and these relationships are expressed in gnomonic projection in Fig. 3.* The narrow dark-etching bands often visible in martensite "needles" were found to be parallel to (112) and thus are undoubtedly twin bands in the martensite crystal.

Jan 1, 1941