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By P. A. Laxen, H. R. Spedden, A. M. Gaudin

WHEN a mineral particle is fractured, bonds between the atoms are broken. The unsatisfied forces that appear at the newly formed surface1 are considered to be responsible for the adsorption of ions at the mineral surface. A knowledge of the mechanism and extent of ion sorption from solution onto a mineral surface is of interest in the development of the theory of flotation.2,3 Study of the adsorption of sodium from an aqueous solution on quartz offers a simple approach to this complicated problem. The availability of a radioisotope as a tracer element meant that accurate data could be obtained.4,5 Three main factors which appeared likely to affect the adsorption of sodium are: 1-concentration of sodium in the solution, 2-concentration of other cations in the solution, and 3-anions present in the solution. Hydrogen and hydroxyl ions are always present in an aqueous solution. By controlling the pH, the concentration of these two ions was kept constant. The variation in the amount of sodium adsorbed with variation in sodium concentration was then determined under conditions standardized in regard to hydrogen ion. The effect of concentration of hydrogen ions and of other cations was also measured. A few experiments were made to get a preliminary idea on the effect of anions. The active isotope of sodium was available as sodium nitrate. Standard sodium nitrate solutions were used throughout these experiments except when the effects of other anions were studied. It was found that sodium adsorption increased with sodium-ion concentration, but less rapidly than in proportion to it. Increasing hydrogen-ion concentration, or conversely decreasing hydroxylion, brings about a comparatively slight decrease in sodium-ion adsorption. Increasing the concentration of cations other than hydrogen or sodium decreases somewhat the adsorption of sodium ion. It would appear as if the kind of anion is a secondary factor in guiding the amount of sodium ion that is adsorbed. Materials and Methods Quartz The quartz was prepared as in previous work in the Robert H. Richards Mineral Engineering Laboratory4 except for the refinement of using de-ionized distilled water for the final washing of the sized quartz, prior to drying5 To minimize the laborious preparation of quartz, experiments were made to determine whether the sodium-covered quartz could be washed free of sodium and re-used. The experiments were successful as indicated by lack of Na' activity on the repurified material and by its characteristic sodium adsorption. Table I gives the spectrographic analyses of the quartz used. The quartz ranged from 16 to 40 microns in size, averaging about 23 microns (microscope measurement), and had a surface of 1850 sq cm per g (lot I), 2210 (lot II) and 2000 (lot III) as determined by the Bloecher method.6 Radioactive Sodium Method of Beta Counting for Adsorbed Sodium: Na22, the radioisotope of sodium, possesses convenient properties.7 It has a half-life of 3 years, thus requiring no allowance for decay during an experiment. On decay it emits a 0.575 mev ß radiation and a 1.30 mev ? radiation. The decay scheme is illustrated in the following equation: [Y Nam S. - 'Net 3 years] The ß radiation is sufficiently strong to penetrate an end-window type of Geiger-Mueller counting tube. This, in turn, makes it possible to use external counting, a great advantage in technique. Furthermore, it permits the assaying of solids arranged in infinite thickness, while assaying evaporated liquors on standardized planchets. The equipment used was standard and similar to that employed by Chang8 The original active material was 1 ml of solution containing 1 millicurie of Na22 as nitrate. This active solution was diluted to 1000 ml. Five milliliters of this diluted active solution was found to give a quartz sample a sufficiently high activity for accurate evaluation of the sodium partition in the adsorption measurements. Also, 1 ml of final solution gave a sufficiently high count for precision on the liquor analyses. The sodium concentration of the diluted active solution was 1.2 mg per liter, so that 6 mg of sodium for 60 ml of test solution and 12 g of quartz was the minimum amount used. The active solution was stored in a Saftepak bottle. Procedure for Adsorption Tests: The method consisted of agitating 12 g of quartz with 60 ml of solution of known sodium concentration for enough time to establish equilibrium between the solution and the quartz surface. The quartz was separated as completely as possible from the solution by filtering and centrifuging. The activity on the quartz and in the equilibrium solution was measured and the partition of the sodium was calculated from the resulting data. The detailed procedure for the adsorption test is set forth in a thesis by Laxen5 In brief, it included the following steps: 1-Ascertainment of linearity between concentration of Na22 and activity measured. 2-Evaluation of factor to translate activity on solid of infinite thickness in terms of activity on an evaporated active film of minute thickness, on the various shelves of the counter shield. 3-Taking precautions to avoid evaporation of water during centrifuging.

Jan 1, 1952

By F. D. Hoyt, H. L. Hartman

The development of new processes and methods by The Pennsylvania State University to improve slate quarrying technology has centered in recent years on cutting and sawing stone in the quarry to eliminate a second cutting process in the mill. Two machines exhibit promise for this work: 1) a circular saw mounting diamonds or hard inserts to produce smaller sizes of stone and 2) a chain saw with insert cutting teeth to produce stone in the larger dimensions. Prototype machines have been constructed and tested in several Pennsylvania slate quarries, and one commercial installation has been operated for several months with a circular diamond saw. Other kinds of dimension stones may be cut by these saws. Research at Penn State has begun to study the fundamental cutting action of rotary tools or saws in slate and other dimension stones. A laboratory drill press is being instrumented to permit thrust-torque-rotational speed us penetration rate studies of single tooth cutting surfaces on stone. Machinability studies of slate conducted with tungsten-carbide inserts have been performed. The dimension stone industry generally accepts the rather basic premise that the larger the block removed from the quarry, the more practical and economical the operation. Thus, the concept of cutting to size any dimension stone while it remains in place in the parent bed would receive little consideration from the majority of members of the industry. However, the slate industry, which is usually considered a separate member of the dimension stone family, is pioneering in the development of an in-place sawing method. Before any final decision can be reached concerning a proposed new system, it is essential to take a long, hard look at the present method of operation in order to determine if the new system is indeed an improvement or even desirable. In the following section is a brief description of present quarry practice in the slate quarries of eastern Pennsylvania. PRESENT METHOD OF QUARRYING SLATE In the numerous slate quarries of Lehigh and Northampton Counties of Pennsylvania, the grain and cleavage of the slate are most often at right angles to each other; if a third surface is broken at right angles to these two natural planes of weakness, blocks of more or less rectangular shape can be separated.' In conventional quarrying a large calyx core drill prepares holes of 36-in. diam in which wire-saw standards are positioned. By wire sawing between strategically located core-drill holes, large sinks or benches of virgin slate are opened up. The sides freed by wire sawing will vary from quarry to quarry but generally are rectangular in shape with dimensions averaging 20 ft in length and about 15 ft in depth. Some quarries are fortunate in having a joint or natural parting to work to, which of course diminishes the amount of core drilling and wire sawing required. Once the various benches have been developed either through wire sawing alone or through a combination of wire sawing and natural jointing planes, the block removal proceeds in the following manner. A plug hole is drilled in the block with a compressed-air hammer and a feathering chisel is inserted in the hole to cause a fracture of the rock either with or against the grain as indicated by the positioning of the so-called feathers. This operation is referred to as sculping. After a block has been freed with and against the grain by means of wedging from the cross fracture with long bars or levers, the block is further freed along the cleavage plane by shimming it up with small wooden pieces in an operation known as styling. A large steel loading chain is wrapped around a block thus freed and the chain is attached to the wheel of an overhead cable. The block is then hoisted vertically to the cableway and moved along this cableway laterally to the lip or edge of the quarry. From here it is unloaded onto a rail car or truck for transportation to the processing mill. Except for occasional blasting to free stubborn blocks,

Jan 1, 1961

By D. G. Westlake

THE structure observed in thin foils by transmission electron microscopy is not necessarily representative of the initial bulk material. We have shown that hydrogen, originally present in a specimen of vanadium, niobium, or tantalum, can be concentrated by the thinning operation used to prepare foils from the bulk materials.' These foils exhibited domain walls indicative of a tetragonal distortion of the bcc unit cells, probably caused by ordering of the hydrogen in preferred interstitial sites. We believe this ordering does not occur at room temperature in the bulk material which contains less than 1 at. pct H. In a continued effort to prepare metal foils whose hydrogen concentrations remain constant during preparation, we have developed some new chemical and electrothinning techniques for vanadium. Each of the procedures presented in Table I produced foils that were thin enough for transmission electron microscopy. The experiments described below were performed to test the effect of each thinning procedure on hydro-

Jan 1, 1968

By Edward A. Loria

A SERIES of papers on the study of austenite grain A size in cast steels has been published recently.'" These studies show that in the as-cast state, the austenite grains are quite large, for they form as the steel freezes at a very high temperature, but a simple reheating above the critical range produces a new set of austenite grains which, in many instances, is finer than ASTM grain sire No. 8. Furthermore, there is no apparent relationship between as-cast austenite grain size and subsequent grain size produced by heat treatment. The as-cast austenite grain size can be determined easily in plain carbon and low alloy steels which produce a continuous grain boundary f errite envelope in the as-cast structure. In the case of cast steels whose alloy content produces greater hardenability and suppresses the proeutectoid ferrite transforma-

Jan 1, 1952

First Session BRASS Wednesday, A.M., Nov. 29 Co-Chairmen: CARTER S. COLE, Staff Engineer, A.S.T.M. E. A. ANDERSON, Chief of Metals Section, Research Div., New Jersey Zinc Co. (of Pa.) Second Session BRASS Wednesday, P.M., Nov. 29 Co-Chairmen: D. K. CRAMPTON, Director of Research, Chase Brass and Copper Co., Inc. A. W. TRACY, Metallurgist, The American Brass Co. Dinner and Technical Session Wednesday Evening, Nov. 29 Toastmaster: N. L. MOCHEL, Manager Metallurgical Engineering, Westinghouse Electric Corp. Talk on "How Do Things Look Today and For the Future" RALPH KELLY, President, Baldwin Locomotive Works Technical Paper on Stress-Corrosion Cracking E. H. Dix, JR., Assistant Director of Research and Chief Metallurgist, Aluminum Company of America Third Session BRASS Thursday, A.M., Nov. 30 Co-Chairmen: W. B. PRICE, Director of Research, Scovill Manufacturing Co. A. L. JAMIESON, Associate Metallurgist, Frankford Arsenal First Session LIGHT METALS Thursday, P.M., Nov. 30 Co-Chairmen: L. L. WYMAN, Metallurgist, General Electric Co. M. A. HUNTER, Professor of Metallurgical Engineering and Head, Dept. of Metallurgical Engineering, Rensselaer Polytechnic Institute Second Session LIGHT METALS Thursday Evening, Nov. 30 Co-Chairmen: R. T. WOOD, Chief Metallurgist, American Magnesium Corp. J. D. HANAWALT, Director, Metallurgical Dept., Dow Chemical Co. First Session STEEL Friday A.M., Dec. I Co-Chairmen: H. S. RAWDON, Chief, Division of Metallurgy, National Bureau of Standards A. L. FEILD, Director of Research, Rustless Iron and Steel Corp. First Session MISCELLANEOUS METALS Friday P.M., Dec. I Co-Chairmen: E. A. ANDERSON, Chief of Metals Section, Research Div., New Jersey Zinc Co. (of Pa.) CARTER S. COLE, Staff Engineer, A.S.T.M.

Jan 1, 1945

By Norman B. Pilling

The technical difficulties hampering the metallographic analysis of silicon steels are chiefly the result of the extreme corrodibility of these alloys. The addition of silicon to iron in increasing quantities, up to about 6 per cent., rapidly increases the susceptibility of the alloy to chemical attack, not only in acid solution, but in water. This renders the preparation of metallographic sections very difficult, because of a non-selective attack upon the finely polished surface by the water used as a lubricant in polishing. This water attack masks the true structural details revealed by suitable etching reagents. It is thus necessary to use alcohol as a polishing lubricant in the last stages of preparation and to avoid all etching reagents having an aqueous base. A specific reagent for the identification of iron carbide in ferrous alloys, and the one hitherto used almost' exclusively by metallurgists, is an alkaline aqueous solution of sodium picrate, which stains this constituent selectively. Its application to silicon steels has not proved successful, as its distinctive selective action is more or less completely hidden by the general attack of the aqueous solvent on the silico-ferrite, greatly accentuated by the fact that this reagent must be used at its boiling temperature (105' C.). Thus, a powerful metallographic aid to the study of the higher silicon alloys, such as transformer steels, is lost. A new reagent has been developed for the purpose of overcoming this difficulty. It is with some hesitation that the list of etching reagents, already overburdened, is increased, but the properties of this new reagent are advantageous in several ways and a definite field for it may be found in the metallography of ferrous alloys. The reagent consists of a dilute solution of nitric acid and methyl alcohol in nitrobenzol. It is a great advantage to secure an anhydrous solution, as a tendency toward acidic etching has been traced to small amounts of water. A convenient method of preparation is to make an anhydrous stock solution of nitric acid in methyl alcohol in the proportion 20 per cent. acid by weight (12.5 per cent. by volume). The alcohol can

Jan 1, 1924

By H. W. Hockin, D. r. Brandt, R. H. Walsh, P. L. Dietz, P. R. Girardot

New Jersey, Florida, and Canadian ilmenites were reduced with hydrogen or coke under various experimental conditions and the phase changes occurring in the ilmenite upon reduction have been studied by microscopic examination of polished sections and by X-ray diffraction. The products formed were dependent upon the type of ilmenite, temperature, time and reducing agent. Of the reducing agents, hydrogen was the more effective at lower temperatures. 1 HE possible utilization of ilmenite as a source of both iron and titanium has resulted in the development of a number of methods for the separation of the iron and titanium content. Slagging processes as currently used in Canada are typical of such methods. Somewhat less attention has been given industrially to the reduction of the iron content at less than the slagging temperature. Although references maybe found to such work, in general only one type of ilmenite, either natural or synthetic, has been studied by each author. We have attempted to draw some relationship between the results of experimental reduction and the type of deposit from which the ilmenite was derived, as evidenced by phases occurring in the ores and in the reduction products. Ilmenite ores having from 27 to 61 pct titanium dioxide were included in this study and in each case reduction was carried out at such temperatures that only limited coalescence of the particulate iron product occurred within the ilmenite grains. The history of the individual ilmenite samples and the temperature of reduction were found to determine the occurrence of various phases and the mode of distribution of the iron. REVIEW OF EARLIER WORK ON REDUCTION One of the earliest references to the reduction of ilmenite at less than the slagging temperature was made in 1917.' The metallic iron produced was_____ leached out by the action of dilute sulfuric or hydrochloric acid, to leave a product high in titanium dioxide. Subsequent to this, numerous patents2-'? and other references13"21 have appeared concerning reduction of ilmenite by carbon, hydrogen, carbon monoxide, methane, coal gas, water gas, or the like in the absence of fluxing agents. Mineragraphic examinations were not reported, and in the main, the only examinations made were chemical analyses. However, in two cases3,13, titanium suboxides were reported in the products and in one case2' rutile was reported, in addition to metallic iron. Both were identified by X-ray diffraction. While reductions in the absence of fluxing agents were generally followed by either a wet or dry chemical process for removal of the metallic iron, a Canadian source17 reported removal of the metallic iron by magnetic separation. By the addition of fluxing agents during reduction, the metallic iron has been coalesced into "pearls." Each reference to such a process23-28 has shown that the coalesced iron could be removed by magnetic or gravity means after the product was crushed. In the absence of fluxes, the coalescence did not generally occur. The major part of the present study has been limited to reductions without fluxing agents in order to determine the primary reactions of naturally occurring ilmenites. Titaniferous iron ores have also been studied,29-33 17, l9 their reduction having been used as the basis of a commercial process for beneficiation of such ores in Norway29 and more recently considered in the United States34,35. The ease of reduction of titaniferous iron ores relative to that of hematite or magnetite has been referred to,33 with the conclusion that the more

Jan 1, 1961

By L. A. Roe, John Jan

Iodine is a soft, lustrous, grayish-black nonmetallic element with a density of 4.9. It is the least active of the four members of the halogen family. The other members are, in order of increasing activity, bromine, chlorine, and fluorine. Iodine is a solid at ordinary temperatures, while bromine is a liquid and chlorine and fluorine are gases. Iodine melts at 113°C and volatilizes at 184.4°C to a blue-violet gas with an irritating odor. It occurs in nature only as iodates and iodides or other combined forms. It was discovered by Bernard Courtois in France in 1811, who noticed its presence as an unknown substance in crude soda ash obtained from burning seaweed. Gay-Lussac recognized it as a new element and named it iode, from the Greek word "ioeides or iodes" for violet color (MacMillan, 1970). The world production is not known with any great certainty, but it is probably between 25 and 35 million lb per year, of which about 30% is consumed in the United States. Geology and Mineralogy Iodine compounds occur as a minor constituent as a mineral in the Chilean nitrate deposits and in solution in brines and seawater. According to the US Geological Survey, it is the 47th most abundant element in the earth's crust. The minerals lautarite, Ca (I03)3 (calcium iodate), and dietzeite, Cat (103)2 (CrO4), (calcium iodate-chromate) are found in Chilean nitrate deposits which are located in Antofagasta and Tarapaca provinces on the eastern slope of the coast range in a desert area. Various brines contain iodine compounds. Seawater contains about 0.05 ppm of iodine and some seaweeds will extract and accumulate it up to 0.45% on a dry basis. Some coals in West Germany also contain iodine compounds. The known and potential sources of iodine reported in 1968 are given in Table 1. Table 2 lists estimated world iodine reserves. Iodine has been recovered from brines in Java, Indonesia, France, England, and the USSR. Iodine has also been recovered from seaweed in Ireland, Scotland, France, Japan, Norway, and the USSR. The indicated reserves and future resources of iodine are large but have never been adequately measured. Analysis Iodine as the free element can be detected by the characteristic blue color it gives to a starch solution. Quantitatively it is determined as the free element by titration with standard thiosulfate solutions using starch as an indicator. Colorimetric methods are also applicable. Markets and Prices Iodine and its compounds are generally marketed in the form of: iodine, crude; iodine, resublimed; calcium iodates; calcium iodide; potassium iodide, sodium iodide, and numerous organic compounds. Product Specifications Crude iodine, World market: 99-99.5% 12. Crude iodine, US produced, average: 99.8% 12. Crude iodine, USP XVII Specs: not less than 99.8% percent I2. Resublimed iodine is usually 99.9% and ACS specifications call for not over 0.005% total bromine and 0.020% nonvolatile materials (Anon., 1971). Prices, c.i.f. United States, for iodine have been steadily increasing from $1.18 per lb of crude in 1967 to $6.37-7.27 in January 1981 (Anon., 1981). In 1980 the price of iodine increased by 50%.

Jan 1, 1983

By N. E. Garner

Laboratory experiments were conducted to investigate the cutting of a single diamond on limestone and shale under simulated down-hole conditions. A high-pressure chamber was modified by adding a rock-rotating device so that planing tests could be run. Weight on the diamond, diamond geometry and differential pressure across the face of the rock were varied. It was found that (I) high differential pressure reduced the volume of rock cut by the diamond at a given bit weight by strengthening the rock and changing the mode of failure; (2) a finely powdered rock left in the bottom of the grooves reduced the volume cut by as much as 50 percent; and (3) orientation of a single diamond about the axis of a drill point had considerable influence on diamond cutting efficiency. INTRODUCTION Diamond bits consist of many diamonds held in a matrix provided with water courses for fluid passage to clean, cool and lubricate the diamonds as they drill formation. Each diamond contributes its share to the overall effectiveness of a bit, but a lack of understanding of the performance of a single diamond has hampered efforts to engineer improvements in diamond bits. The need for those improvements prompted this study. This paper describes the findings of a laboratory investigation of the outting action of a single diamond where the differential pressure between the wdlbore and formation, diamond geometry and vertical force on the diamond were independently varied. The tests were conducted in a pressure chamber that provided relative horizontal motion (planing) between a rock and diamond under simulated down-hole pressure conditions. EQUIPMENT HIGH-PRESSURE CHAMBER WITH ROTATING DEVICE The high-pressure chamber used in previous rock mechanics studies' was modified for this study by addition of a rock-rotating device. The modified chamber (Fig. 1) differs from the old chamber in that the rock can be rotated to provide relative horizontal movement between the rock and the penetrator which may be a small element of a diamond or a drag bit. In this study the penetrator was a single diamond. The rock sample holder inside the chamber is mounted on a thrust bearing and is connected to the external drive mechanism by a stem that passes through two seal elements. The seal elements are needed to allow formation pressure to enter the bottom of the rock sample through a small hole in the stem. The Kapseal seal elements (Tefion boots backed by O-rings) provide low friction (hand free) even at differentials of 5,000 psi. The drive mechanism is a variable-speed transmission with a speed range from 0 to 30 rpm and an output torque of 2,800 in.-lb. A right-angle-drive gear box couples the drive to the stem. The new design has two independent pressure systems (formation and borehole) to simulate down-hole rock stress environment. Formation pressure enters from the bottom of the rock through a 6-in. diameter area, and borehole pressure acts over the remaining surface. A 14-in. layer of zero fluid loss oil-base mud poured over the top of the rock and an O-ring seal on bottom allow a differential between the borehole and formation pressures. Bayol 50 was used as the hydraulic fluid in the chamber. The differentials reported here were obtained by elevating the borehole pressure while keeping the formation pressure at zero.

Despite the uncertain political situation in Katanga, copper and cobalt mining and metallurgical operations of Union Miniere du Haut-Katanga were normal at the time of this writing. In fact operations continued normal after Congo independence on June 30, 1960, with copper and zinc production for that year being slightly higher than in 1959. United Nations military operations from September to December 1961 resulted in death, shutdowns and damage to company persons and installations. Nevertheless, results for that year were only slightly off normal production. Moise Tshombe delared Katanga a separate state after Congo independence. Although there has been tribal unrest, the new State has enjoyed relative calm and normal industry by comparison with other parts of the Congo as a result of the firm hand of Moise Tshombe's government and the continued presence of Belgian officials and technicians.

Jan 12, 1962

By A. W. Demmler

RECENTLY, Chaudron,&apos; Montariol,2 and their co-workers published the results of their studies on zone-refined aluminum. They found their material to be capable of recrystallization at —50°C, but gave no data as to the percentage reduction or time required. Their material was found to be practically non-work hardening at room temperature, but after 96 pct cold work at a low temperature and storage in liquid nitrogen it was found to recrystallize to coarse grains in less than 3 hr at 20°C. Recently, a study was made of the room temperature recrystallization characteristics of zone-melted aluminum. An ingot 14 in. in length, with a 3hx3 in. cross section, was made in an extremely high purity graphite boat under an atmosphere of dried commercial argon. It was made by first passing the molten zone along the ingot of 99.99+ pct A1 15 times. At this point, the most impure 3 in. (the end toward which the eutectic forming impurities migrated) were replaced with more of the original starting material, and 15 more traverses were made. Each traverse of the zone along the ingot required approximately 3 hr. Three ingots were prepared in this identical fashion and the chemical analyses were made spec-trographically on two of these ingots, rather than on the one used in this investigation. The analyses were made at 1 in. intervals along the ingot, in duplicate. Over the purest 5 in. of the ingot, which were most important in this investigation, there was found an average composition of <0.00004 pct Cu, <0.0003 pct Fe, <0.0001 pct Si, and <0.0001 pct Mg. In addition, the following elements were not detected spectrographically even in the more impure end of the bar: manganese, zinc, nickel, chromium, titanium, vanadium, lead, tin, boron, beryllium, bismuth, gallium, zirconium, cadmium, antimony, cobalt, and molybdenum. The original ingot was given several cold reductions, with intermediate anneals in order to refine the grains. Owing to the extreme length resulting and the ease of deforming the material plastically, it was cut into eight equal lengths and identified as shown in Fig. 1, with the highest numbered section at the purer end (that enriched with peritectic formers). Section 6 was used in the exploratory work and was found to be of exceptionally high purity, giving more rapid rates of room temperature re crystallization than any previous aluminum studied at the Alcoa Research Laboratories. This fact suggested that the entire midsection of the ingot might be of very high purity. Accordingly, section 4 was chosen for the next study. A portion of it was rolled to cold reductions of 10, 25, 40, 60, 75, and 90 pct at room temperature, and the re-crystallization of each specimen was followed by X-ray pinhole transmission photographs. The other portion received the same treatment, except that both the specimens and the rolls were maintained at 160°F in the process of rolling. The latter ortion was retarded in its recrystallization as compared to the former, probably due to the stress relief effect of the warm rolling. Both of these portions of the fourth section were found to recrystallize at a considerably slower rate than did the sixth section.

Jan 1, 1957

By AIME AIME

UNQUESTIONABLY the Coal Division has never had a meeting in which so many outstanding technical papers were presented of immediate practical application to problems of personnel, mining, safety, preparation, combustion, and carbonization. Should there have been those present with the lingering idea that all that was needed for success in the coal industry was a strong back and a weak mind they must have had a rude awakening.

Jan 1, 1942

The 114th (New York) Meeting of the Institute will be held in the third week of February, 1917. The Committee on Papers and Publica- tions has set Dec. 1,1916, as the closing date for the receipt of manuscripts intended for this meeting. Manuscripts must be received by the Secretary on or before this date. If they are sent through members of the technical committees they must be sent to those committees enough in advance of the time to be forwarded and in the hands of the Secretary by the time specified. While Dec. 1, 1916, is the final closing date, it is a great advantage to get papers in as much before that time as possible as it enables them to be submitted in proof form to their authors. Papers received on or before

Jan 10, 1916

By Alden B. Greninger

Twinned metal crystals are usually designated as either deformation twins or annealing twins. If twins are to be classified according to the treatment the metal has undergone just prior to the observation of the twins, there are two other possible groups: (1) solidification twins,† when observed in the as-solidified or as-cast condition, and (2) transformation twins,† when observed in a metal which has been cooled from above an allotropic transformation temperature. McKeehan has demonstrated that ferrite does, occasionally at least, contain twinned structures2. The twins, which he studied by optical methods, were obtained during the preparation of iron single crystals by very slow cooling through A3. He proved that the twin relation was actually that which previous investigators had predicted; namely, twinning along three planes of the form (112). Since McKeehan&apos;s discovery, little or no attention has been given to this transformation twinning of alpha iron, or to the possibility that it might occur at all speeds of cooling from above A3 instead of merely during the preparation of single crystals. McKeehan&apos;s twins were evidently regarded as interesting only in proving that a body-centered cubic metal could form twinned structures—at least under certain conditions. It is generally believed that iron seldom if ever forms annealing twins. Certainly the straight-line banding which is so abundant in annealed face-centered cubic metals is characteristically absent in iron annealed below A3. However, O&apos;Neil13 has studied "twin-like" crystals in annealed alpha iron and concludes that the specimen he studied actually contailled a few annealing twins. Tamura4 as reported "twin-like" crystals both in wrought iron and mild steel; specimens of the latter were annealed above and below A3 and showed "twin-like" crystals after both kinds of treatments.

Jan 1, 1936

By Alden B. Greninger

Twinned metal crystals are usually designated as either deformation twins or annealing twins. If twins are to be classified according to the treatment the metal has undergone just prior to the observation of the twins, there are two other possible groups: (1) solidification twins,† when observed in the as-solidified or as-cast condition, and (2) transformation twins,† when observed in a metal which has been cooled from above an allotropic transformation temperature. McKeehan has demonstrated that ferrite does, occasionally at least, contain twinned structures2. The twins, which he studied by optical methods, were obtained during the preparation of iron single crystals by very slow cooling through A3. He proved that the twin relation was actually that which previous investigators had predicted; namely, twinning along three planes of the form (112). Since McKeehan&apos;s discovery, little or no attention has been given to this transformation twinning of alpha iron, or to the possibility that it might occur at all speeds of cooling from above A3 instead of merely during the preparation of single crystals. McKeehan&apos;s twins were evidently regarded as interesting only in proving that a body-centered cubic metal could form twinned structures—at least under certain conditions. It is generally believed that iron seldom if ever forms annealing twins. Certainly the straight-line banding which is so abundant in annealed face-centered cubic metals is characteristically absent in iron annealed below A3. However, O&apos;Neil13 has studied "twin-like" crystals in annealed alpha iron and concludes that the specimen he studied actually contailled a few annealing twins. Tamura4 as reported "twin-like" crystals both in wrought iron and mild steel; specimens of the latter were annealed above and below A3 and showed "twin-like" crystals after both kinds of treatments.

Jan 1, 1936

By Herbert J. French

Herbert 1. French (Member 1934), vice president of the International Nickel Co. Inc., assistant vice president of the International Nickel Co. of Canada Ltd., and AIME Howe Memorial Lecturer for 1956, died in Rochester, Minn. on Aug. 17, 1955, after a long illness. Before his death, Mr. French had laid the foundation of research on which the Howe Memorial Lecture (p. 770) was based. His associates at Inco, 0. 0. Miller and J. W. Sands, were able to complete the project, present the lecture, and prepare it for publication, following Mr. French&apos;s general outline. Born in New York on May 27, 1893, he graduated from the School of Mines, Columbia University, with a degree in metallurgical engineering in 1915. Mr. French gained his early engineering experience with the American Smelting and Refining Co., serving as a chemist and as-sayer at the company&apos;s Murray, Utah, installations. He later returned east and became a metallurgical engineer for the General Vehicle Co., Long Island City, IT. Y., a subsidiary of the General Electric Co. In 1917 Mr. French was appointed civilian inspector of materials for the U.S. Army Signal Corps, and continued this work when it was later absorbed into the Bureau of Aircraft Production. Subsequently he was appointed district inspector in Philadelphia for the Pittsburgh (Ordnance Metallurgical) office, later transferring to Pittsburgh. After World War I Mr. French became an assistant physicist on the metallurgical staff, U. S. Bureau of Standards, Washington, D. C. During his years with the Bureau, he was successively associate physicist, metallurgist, senior metallurgist, and assistant chief, division of metallurgy. In 1929 Mr. French joined International Nickel as a metallurgist at the company&apos;s Bay-onne, N. J., research laboratory. Transferring to the development and research division, New York, in 1931, he took charge of alloy steel and iron development, becoming assistant manager of this division in 1943. Mr. French&apos;s appointment as an Inco vice president came in March 1947. Previously, he was appointed assistant vice president of the International Nickel Co. of Canada Ltd. in January 1947. Mr. French served the War Production Board during World War II as senior technical consultant in charge of the metallurgical and specifications section of the iron and steel branch. When this section of the WPB was organized into the steel division, he was appointed chief of the metallurgical branch. From March 1944 to September 1945 Mr. French served as assistant director. Herbert French was well known not only for his prolific contribution to the metallurgical literature, for which he received numerous awards, but also for his prolonged service to the profession through its technical societies. He was a past president of ASM, and was the Campbell Memorial Lecturer for that group in 1933. Mr. French was honored by the American Society for Steel Treating in 1931 when he was awarded the Henry Marion Howe Medal. A series of lectures he gave in 1941 before the Fourth Western Metal Congress in Los Angeles was later published in book form under the title Alloy Constructional Steels.

Jan 1, 1957

By H. D. Kessler, Joseph B. McAndrew

WHEN there is occasion to make structural use of metals at temperatures above 900°C (1652°F), the choice of alloys is severely limited, and those materials which meet special requirements as to density, strength, toughness, and resistance to creep, oxidation, or fatigue at such temperatures are at a premium. Any new type of high temperature alloy which is found to be outstanding with respect to several of these properties is therefore likely to find special applications for which it is uniquely advantageous as compared to other alloys. Such is the case with the 7 titanium-aluminum alloys. This y phase is an intermediate phase based on the composition TiAl, and extends from about 35.5 to 44.5 wt pct Al at temperatures up to 1000°C, above which the field broadens to include 60 pct A1 at 1340°C.&apos; The alloys of principal interest have a narrow melting range, with 7 forming by the peri-tectic reaction, melt + ß=y at about 1460°C. Unlike most intermediate phases, the binary alloys containing titanium and aluminum in approximately equiatomic proportion possess low room temperature hardness,&apos; in addition to which they have low density, good resistance to oxidation, and relatively high modulus of elasticity.&apos; Unpublished work done at Armour Research Foundation showed

Jan 1, 1957

By Foster Fraas

MOST commercial electrostatic separators utilize the electrical property of conductivity, but although based on the same principles, they are constructed in a variety of forms, a common one being the simple roll type. Some information obtained during an investigation of that type of separator, and which indirectly is applicable to other types, is presented here. NUMERICAL RELATIONSHIP In Fig. I material discharged from hopper 6 is fed onto grounded rotating roll 2. Electrode 3 is at a high electrical potential with respect to roll 2, and any conductive particle in contact with roll 2 therefore acquires an electrical charge of such polarity that, when present in the electrical field, the force on it is in the direction of electrode 3. A detailed description of the charging by conductance as utilized in electrostatic separators may be found in a previous publication.1 As a result of this force, the path of the projected particle is changed in increasing amounts in the direction toward region C as the magnitude of the charge is increased. With the dividing edge 4 the projected particles may be divided into two fractions -those in region C designated as "deflected" or " deflectant " and those in region B designated as "residue." When material is passed over the roll only once, a complete separation is seldom obtained, therefore most commercial separators contain several roll-separator units in [ ] series, and some practical machines use as many as 12. In this paper a "pass" means the passage of material over a single-roll unit. The procedure is to repass either residue B with a low potential on electrode 3 or deflectant C with a high potential on 3. Most electrostatic separations follow a flowsheet of roughing and cleaning either the concentrate or the tailing, on both. In a specific instance, a dry, heated mixture of wet cleaned chromite and garnet from an

Jan 1, 1942

By Alfred Siegel

Mineral pigments give color, opacity, or body to paint, stucco, plaster, mortar, cement, linoleum, rubber, and similar materials. They must be finely divided, substantially insoluble, and generally inert for such uses. Inorganic pigments may be grouped somewhat arbitrarily as follows: A. Natural mineral pigments dug from the earth. 1. Those consisting mostly of iron oxides, such as hematite and limonite. 2. Those containing large amounts of clay or noncoloring matter, such as ocher, sienna, umber, and colored shales. 3. Those whose color is not due to iron oxide, such as Vandyke brown (including sap brown, an alkali extract of Vandyke brown), graphite, and terre verte. B. Synthetic pigments. 1. Those containing iron oxide as the essential coloring matter, such as "pure" reds, yellows, and blacks, and Venetian reds. 2. Those not containing iron oxide, but rather such compounds as lithopone, zinc white, titanium white, ultramarine, Prussian blue, and the like. Only groups A and B-1 are discussed here. All the pigments in those two categories, except Vandyke brown, sap brown, and some of the carbonaceous slates, contain, as their essential color constituents, one or more compounds of iron; namely, an oxide-limonite (2Fe2O3.H2O to Fe2O3.4H20), hematite (Fe2O3), or magnetite (Fe2O3.FeO). Man&apos;s first permanent coloring materials were earth pigments-the ochers, iron oxides, and various iron-stained clays. The caves occupied by prehistoric man and the arts of the ancient Chaldean, Egyptian, and Cretan civilizations bear mute witness to this and also testify to the beauty and permanence of earth colors. As the Roman era developed, earth pigments were pushed from their pre-eminent position by white lead and red lead and in the Middle Ages by zinc oxide. Today, of course, the number of acceptable pigments is very large and on a value basis the group of natural and synthetic earth pigments stands forth with $16,000,000 per year; it is surpassed by titanium, lead and zinc pigments. Of this sum,21 natural pigments supplied 31 pct of the tonnage and 16 pct of the value of the total finished pigment in 1957, the remainder representing the tonnage and value of sales of the synthetic iron oxide colors. The average value of finished natural pigments in 1958 was $80.62 per ton. The average value of manufactured pigments in the same year was $202 per ton. Of the 60,000 tons of manufactured colored pigments sold in 1958, the reds comprised 76 pct of the market and the yellows 20 pct. The reds furnished 68 pct of the value and the yellows 24 pct. Of the finished iron oxide pigments (natural and manufactured) sold in 1958, the reds dominated the market with 66 pct of the quantity and 63 pct of the value; yellows supplied 17 pct of the quantity and 20 pct of the value, and browns furnished 11 pct of the quantity and 10 pct of the value. The average value of the reds was approximately $152, and the average value of the yellows $190 per ton. The highest valued pigment in 1958, with almost 12 pct of the total tonnage and 21 pct of the value of the iron oxide pigment market, was manufactured red from calcined copperas valued at $286 per ton.

Jan 1, 1960

By Foster Fraas

Most commercial electrostatic separators utilize the electrical property of conductivity, but although based on the same principles, they are constructed in a variety of forms, a common one being the simple roll type. Some information obtained during an investigation of that type of separator, and which indirectly is applicable to other types, is presented here. In Fig. I material discharged from hopper 6 is fed onto grounded rotating roll 2. Electrode 3 is at a high electrical potential with respect to roll 2, and any conductive particle in contact with roll 2 therefore acquires an electrical charge of such polarity that, when present in the electrical field, the force on it is in the direction of electrode 3. A detailed description of the charging by conductance as utilized in electrostatic separators may be found in a previous publication.&apos; As a result of this force, the path of the projected particle is changed in increasing amounts in the direction toward region C as the magnitude of the charge is increased. With the dividing edge 4 the projected particles may be divided into two fractions —those in region C designated as "deflected" or"deflectant"and those in region B designated as "residue." When material is passed over the roll only once, a complete separation is seldom obtained, therefore most commercial separators contain several roll-separator units in series, and some practical machines use as many as I2. In this paper a "pass" means the passage of material over a single-roll unit. The procedure is to repass either residue B with a low potential on electrode 3 or deflectant C with a high potential on 3. Most electrostatic separations follow a flowsheet of roughing and cleaning either the concentrate or the tailing, or both. In a specific instance, a dry, heated mixture of wet cleaned chromite and garnet from an

Jan 1, 1943