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By H. D. Wilde

GREAT emphasis is being placed today on petroleum as a source of chemicals. Such prominence is well merited, for rapid strides have been made in developing processes for the conversion of petroleum into synthetic chemical products, which are now being made on a huge scale. These marvelous accomplishments have resulted in some highly optimistic predictions as to what can be expected in the future. Many of these forecasts are well justified, but some writers, especially those contributing to the Sunday supplements and the popular-cience type of publications, have let their imagination run wild and present a rather distorted picture of the possibilities in this field in the postwar period. Commercial manufacture of synthetic organic chemicals had its beginning in England with the establishment of a plant by Sir William Perkin in 1857 for the manufacture of "Aniline Purple" or "Mauve." The preceding year he had discovered in the laboratory how this dyestuff could be made from aniline, one of the many derivatives of coal tar, and he soon made commercial application of his discovery. Influenced largely by his success, organic chemists began research on production of a vast array of synthetic dyestuffs, medicinals, flavors, scents, and explosives. Rapid progress was made and by the turn of the century hundreds of these products were being manufactured. Most of these synthetic chemicals were derived from materials obtained as by-products in the conversion of coal into coke. These by-products are generally referred to as "aromatics" and are obtained by processing coal tar recovered in the coking process, so they are popularly known as "coal-tar chemicals." During the early years of this century, coal-tar chemistry was the wonder of the age, and rightfully so, since the products so made seemed limitless.

Jan 1, 1944

By AIME AIME

HEREWITH is presented a preliminary report of a special committee, consisting of Erle V. Daveler, Paul D. Merica, and C. H. Mathewson (chairman), dealing with sundry matters of which many are of vital interest to all members of the American Institute of Mining and Metallurgical Engineers. As the report states, the initial purpose of the investigation was to determine ways and means to stimulate "the welfare and growth" of the Institute of Metals and Iron and Steel Divisions. However, it soon became apparent to the committee that most of the problems and possible correctives were of no less vital concern 1o members of the other Divisions and to the "unattached" group of members. Consequently, the Committee has authorized publication of the report and invites written comment from any member on the specific recommendations or on any other phase of the broad subject.

Jan 1, 1943

By E. P. Sadowski, L. P. Trudeau, C. R. Cupp

The apparent high radiation resistance of two varieties of maraging steel is described and an indication is given of some phenomena that require further study. Two aspects were included in this work: a) effects of neutron irradiation on the room-ternperature tensile properties of 18 Ni (250) maraging steel; b) effects of neutron irradiation on the room-temperature tensile properties and on the impact resistance of 12 pct Ni-5pct Cr-3 pct Mo maraging steel. Subsize tensile and impact test specimens were used. The 18 pct Ni steel was irradiated to a neutron fluence of 3.3 x 10 n per sq cm (>1 mev). The 12-5-3 variety was irradiated to two neutron fluence levels: 1) 1.5 x 10 per sq CTTL (>I mev) 2) 3.1 x 10'9nper sq cm (>1 mev) In all respects both varieties showed unusually high resistance to change in strength and ductility after neutron irradiation. There was no noteuorthy over-aging in fully aged specimens. The aged 18 pct Ni variety showed a 4 pct drop in yield strength upon irradiation with little or no decrease in ductility. The aged 12-5-3 variety showed a 5 pct increase in yield strength on irradiation with a very slight decrease in ductility. The impact transition of the 12-5-3 variety only increased 35 to 45 Co upon irradiation, and the shear energy fracture value for the subsized specimens decreased only half as much as expected frorn experience with conventional steels. THE development of new reactor concepts and nuclear technology now depends to a large extent on the availability of new alloys capable of operating in stringent reactor environments. One of the most important new types of metallurgical material that has been developed in recent years is the maraging steels. This type of alloy is notable for its remarkable retention of toughness at high strength levels. In the course of a research program which incorporated ambient temperature radiation effects studies to determine the mechanisms of strengthening of 18 pct nickel maraging steel,' it became evident that the resistance of the alloy to neutron-induced changes in mechanical properties should be studied. This paper is to present evidence for the apparent high radiation resistance of maraging steel. The experimental program was in two parts: a) Effect of neutron irradiation on the room-temperature tensile properties of 18 Ni (250) maraging steel. b) Effect of neutron irradiation on the room-temperature tensile properties and on the impact resistance of 12 pct Ni-5 pct Cr-3 pct Mo maraging steel, a cobalt-free alloy. EXPERIMENTAL PROCEDURE 18 Ni (250) Maraging Steel. Tensile test specimens were machined to the dimensions shown in Fig. 1 from $-in.-diam hot-rolled bar of the composition shown in Table I. All specimens were austenitized for 1 hr at 1500°F (815°C) in argon and water-quenched. Half of the specimens were then mar aged for 3 hr at 900° F (482°C) in argon. The specimens were irradiated in a fast neutron transformer rod at approximately 120°F (50°C) to a neutron fluence of 3.3 x 10 10 n per sq cm (>1 mev). The irradiation was performed in the NRX reactor of Atomic Energy of Canada, Ltd., at Chalk River, Ontario, Canada. In all cases, the thermal neutron flux was three times as high as the reported (> 1 mev) fluxes. The room-temperature tensile tests were performed with an Instron tensile testing machine operating at a crosshead speed of 0.05 in. per min. The loading frame of the machine, mounted in a hot cell, was remotely controlled. The specimens were tested either

Jan 1, 1968

By Guy N. Bjorge

HOMESTAKE'S mining methods today are of necessity controlled to a considerable extent by that which has been done in the past. This may be shown by the fact that our two main operating shafts now, the B. & M. and Ellison, were begun in 1878 and 1896 respectively, so that-the loca-tions of shafts, locations of all the drifts on the upper levels, and a great deal of sloping was done before any of us now connected with the mine had anything to do- with it. Anything that I may say is not to be construed as criticism of those who have gone before for it would be a sad commentary indeed on us if we had not learned something from their experience. The levels down to the 1100 in the Homestake mine are spaced at 100-ft. intervals, and below that at 150-ft. intervals. The general plan of develop-

Jan 1, 1934

By J. A. Barr, R. B. Burt, I. S. Tillotson

THE pumping of solids in water suspension is an important part of many metallurgical and mining operations. In most cases, it is still in the rule of thumb category for which no universal formula has been developed, and much research is needed. Because of the limited and incomplete data available, this article may be classed as an experience paper, which is presented with the hope that some contribution will be made toward the development of the so-called universal formula. This formula, if and when developed, may be evolved from several factors, many of which are not now available for general application. The designing engineer is interested in obtaining accurate forecasts on: 1—the minimum velocities needed to prevent choke-ups in the pipeline, which in turn dictates pipe sizes, 2—power required for pumping, 3—pump selection. The basic factors for a given problem will include: 1—weight per unit of time of solids to be handled, 2—specific gravity of solids, for calculation of volume, friction and power, 3—screen analysis of solids with the colloidal acting, i.e., the slime fraction, a very important factor, 4— shape of particle or some means of determining a friction constant, 5—effects of percentage of solids, 6—development of a viscosity factor to be used in the overall calculations, 7—calculation of the lower limits of pipeline velocities permissible, 8—calculation of total head, pump horsepower, and 9—setting up of pump specifications. In certain limited cases horsepower and total heads and minimum velocities may be computed and a suitable pump selected from basic data, but in many cases, as in mining of Florida pebble phosphate, experience rather than a hydraulic formula still should be used as a basis of selection. Pumping Florida Pebble Matrix Pumping at the Noralyn mine of International Minerals and Chemical Corp. will be used as an example. Other areas will vary as to the characteristics of the matrix, especially the slime content. A typical screen analysis of this matrix is: +14 mesh, pebble size,* 2.1 pct; —14 +35 mesh, 11.4 pct; -35 +I50 mesh, 60.5 pct; -150 mesh, 25.0; total, 100 pct; moisture in bank, 20.0 pct; weight per cu ft in bank, 120 lb. The —150 mesh fraction may increase to as much as 35 pct in adjacent areas. When thoroughly elutriated, the matrix has a relatively slow settling rate, which is an important factor in permitting lower pipeline velocities without choke-ups. Exact data is not available to evaluate settling rates. For a factor of 100 a suspension of clean building sand in water is suggested. When pumping long distances, a quick settling matrix allows the coarser solids to settle out along the bottom of the pipeline, causing drag, turbulence, and increased friction. With a slow settling matrix as at Noralyn, turbulence acts to keep the solids in suspension at a lower friction head, regardless of the pumping distance. When the pebble content of the matrix, i.e., the + 14 mesh fraction, is in excess of 10 pct of the total solids, trouble may be expected from settling out even in normal pumping distances. To prevent choke-ups and maintain tonnage, an additional pump must be added in the long runs, where one pump would otherwise be satisfactory. A typical pulp handled is: total volume, 7800 gpm; water, 4500; solids pumped per hr, 4200 lb; sp gr pulp, 1.4; percent solids in pulp, 46.; pipe size, 16-in. ID; pulp velocity, 12.85 fps; probable critical velocity, 10 fps, as below this minimum velocity choke-ups would be numerous. In calculating friction heads the Armco handbook is used where a roughness factor based on 15-year-old pipe is set up. Because the pipe used in pumping matrix is smooth and polished because of the scouring action of the phosphate and its silica content, the head losses in the Armco table for water are practically the same as in pumping the Noralyn matrix through smooth pipe, plus the fact that conditions vary widely over short periods, making accurate determinations difficult to obtain. New pumps and pump changes are being tested continuously and a wealth of data built up. This has resulted in a substantial improvement and lower relative costs in pumping matrix. The Florida phosphate industry is constantly seeking to offset higher wage and material costs with improved technique. Until a few years ago a 12-in. discharge pump was commonly used, with heads as low as 80 ft. Sizes have gradually increased and heads more than doubled. For example, the following pump was placed under test at the Noralyn mine: make, Georgia Iron Works; size, suction 16 in., discharge 14 in.; impeller, 39-in. diam; motor, 600 hp, slip ring; full load speed, 514 rpm. The results were increased head, higher capacity than the older design, with fewer pumps in the line from mine to washer.

Jan 1, 1953

By R. B. Burt, J. A. Barr, I. S. Tillotson

THE pumping of solids in water suspension is an important part of many metallurgical and mining operations. In most cases, it is still in the rule of thumb category for which no universal formula has been developed, and much research is needed. Because of the limited and incomplete data available, this article may be classed as an experience paper, which is presented with the hope that some contribution will be made toward the development of the so-called universal formula. This formula, if and when developed, may be evolved from several factors, many of which are not now available for general application. The designing engineer is interested in obtaining accurate forecasts on: 1—the minimum velocities needed to prevent choke-ups in the pipeline, which in turn dictates pipe sizes, 2—power required for pumping, 3—pump selection. The basic factors for a given problem will include: 1—weight per unit of time of solids to be handled, 2—specific gravity of solids, for calculation of volume, friction and power, 3—screen analysis of solids with the colloidal acting, i.e., the slime fraction, a very important factor, 4— shape of particle or some means of determining a friction constant, 5—effects of percentage of solids, 6—development of a viscosity factor to be used in the overall calculations, 7—calculation of the lower limits of pipeline velocities permissible, 8—calculation of total head, pump horsepower, and 9—setting up of pump specifications. In certain limited cases horsepower and total heads and minimum velocities may be computed and a suitable pump selected from basic data, but in many cases, as in mining of Florida pebble phosphate, experience rather than a hydraulic formula still should be used as a basis of selection. Pumping Florida Pebble Matrix Pumping at the Noralyn mine of International Minerals and Chemical Corp. will be used as an example. Other areas will vary as to the characteristics of the matrix, especially the slime content. A typical screen analysis of this matrix is: +14 mesh, pebble size,* 2.1 pct; —14 +35 mesh, 11.4 pct; -35 +I50 mesh, 60.5 pct; -150 mesh, 25.0; total, 100 pct; moisture in bank, 20.0 pct; weight per cu ft in bank, 120 lb. The —150 mesh fraction may increase to as much as 35 pct in adjacent areas. When thoroughly elutriated, the matrix has a relatively slow settling rate, which is an important factor in permitting lower pipeline velocities without choke-ups. Exact data is not available to evaluate settling rates. For a factor of 100 a suspension of clean building sand in water is suggested. When pumping long distances, a quick settling matrix allows the coarser solids to settle out along the bottom of the pipeline, causing drag, turbulence, and increased friction. With a slow settling matrix as at Noralyn, turbulence acts to keep the solids in suspension at a lower friction head, regardless of the pumping distance. When the pebble content of the matrix, i.e., the + 14 mesh fraction, is in excess of 10 pct of the total solids, trouble may be expected from settling out even in normal pumping distances. To prevent choke-ups and maintain tonnage, an additional pump must be added in the long runs, where one pump would otherwise be satisfactory. A typical pulp handled is: total volume, 7800 gpm; water, 4500; solids pumped per hr, 4200 lb; sp gr pulp, 1.4; percent solids in pulp, 46.; pipe size, 16-in. ID; pulp velocity, 12.85 fps; probable critical velocity, 10 fps, as below this minimum velocity choke-ups would be numerous. In calculating friction heads the Armco handbook is used where a roughness factor based on 15-year-old pipe is set up. Because the pipe used in pumping matrix is smooth and polished because of the scouring action of the phosphate and its silica content, the head losses in the Armco table for water are practically the same as in pumping the Noralyn matrix through smooth pipe, plus the fact that conditions vary widely over short periods, making accurate determinations difficult to obtain. New pumps and pump changes are being tested continuously and a wealth of data built up. This has resulted in a substantial improvement and lower relative costs in pumping matrix. The Florida phosphate industry is constantly seeking to offset higher wage and material costs with improved technique. Until a few years ago a 12-in. discharge pump was commonly used, with heads as low as 80 ft. Sizes have gradually increased and heads more than doubled. For example, the following pump was placed under test at the Noralyn mine: make, Georgia Iron Works; size, suction 16 in., discharge 14 in.; impeller, 39-in. diam; motor, 600 hp, slip ring; full load speed, 514 rpm. The results were increased head, higher capacity than the older design, with fewer pumps in the line from mine to washer.

Jan 1, 1953

By R. B. Burt, James A. Barr, I. S. Tillotson

THE pumping of solids in water suspension is an important part of many metallurgical and mining operations. In most cases, it is still in the rule of thumb category for which no universal formula has been developed, and much research is needed. Because of the limited and incomplete data available, this article may be classed as an experience paper, which is presented with the hope that some contribution will be made toward the development of the so-called universal formula. This formula, if and when developed, may be evolved from several factors, many of which are not now available for general application. The designing engineer is interested in obtaining accurate forecasts on: 1-the minimum velocities needed to prevent choke-ups in the pipeline, which in turn dictates pipe sizes, 2-power required for pumping, 3-pump selection. The basic factors for a given problem will include: 1-weight per unit of time of solids to be handled, 2-specific gravity of solids, for calculation of volume, friction and power, 3-screen analysis of solids with the colloidal acting, i.e., the slime fraction, a very important factor, 4-shape of particle or some means of determining a friction constant, 5-effects of percentage of solids, 6-development of a viscosity factor to be used in the overall calculations, 7-calculation of the lower limits of pipeline velocities permissible, 8-calculation of total head, pump horsepower, and 9-setting up of pump specifications. In certain limited cases horsepower and total heads and minimum velocities may be computed and a suitable pump selected from basic data, but in many cases, as in mining of Florida pebble, phosphate, experience rather than a hydraulic formula still should be used as a basis of selection. Pumping Florida Pebble Matrix Pumping at the Noralyn mine of International Minerals and Chemical Corp. will be used as an example. Other areas will vary as to the characteristics of the matrix, especially the slime content. A typical screen analysis of this matrix is: +14 mesh, pebble size,* 2.1 pct; -14 +35 mesh, 11.4 pct; -35 +150 mesh, 60.5 pct; -150 mesh, 25.0; total, 100 pct; moisture in bank, 20.0 pct; weight per cu ft in bank, 120 lb. The -150 mesh fraction may increase to as much as 35 pct in adjacent areas. When thoroughly elutriated, the matrix has a relatively slow settling rate, which is an important factor in permitting lower pipeline velocities without choke-ups. Exact data is not available to evaluate settling rates. For a factor of 100 a suspension of clean building sand in water is suggested. When pumping long distances, a quick settling matrix allows the coarser solids to settle out along the bottom of the pipeline, causing drag, turbulence, and increased friction. With a slow settling matrix as at Noralyn, turbulence acts to keep the solids in suspension at a lower friction head, regardless of the pumping distance. When the pebble, content of the matrix, i.e., the +14 mesh fraction, is in excess of 10 pct of the total solids, trouble may be expected from settling out even in normal pumping distances. To prevent choke-ups and maintain tonnage, an additional pump must be added in the long runs, where one pump would otherwise be satisfactory. A typical pulp handled is: total volume, 7800 gpm; water, 4500; solids pumped per hr, 4200 lb; sp gr pulp, 1.4; percent solids in pulp, 46.; pipe size, 16-in. ID; pulp velocity, 12.85 fps; probable critical velocity, 10 fps, as below this minimum -velocity choke-ups would be numerous. In calculating friction heads the Armco handbook is used where a roughness factor based on 15-year-old pipe is set up. Because the pipe used in pumping matrix is, smooth and- polished because of the scouring, action of the phosphate and its silica content, the head losses in the Armco table for water are practically the same as in pumping the Noralyn matrix through smooth pipe, plus the fact that conditions vary widely over short periods, making accurate determinations difficult to obtain. New pumps and pump, changes are being tested continuously and a wealth of data built up. This has resulted in a substantial improvement and lower relative costs in pumping matrix. The Florida phosphate industry is constantly seeking to offset higher wage and material costs with improved technique. Until a few years ago a 12-in. discharge pump was commonly used, with heads as low as 80 ft. Sizes have gradually increased and heads more than doubled. For example, the following pump was placed under test at the Noralyn mine: make, Georgia Iron Works; size, suction 16 in., discharge 14 in.; impeller, 39-in. diam; motor, 600 hp, slip ring; full load speed, 514 rpm. The results were increased head, higher capacity than the older design, with fewer pumps in the line from mine to washer.

Jan 1, 1952

By W. F. Holbrook

In a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO. In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 per cent MgO slags over the range 1475' to 1525' C. is included. The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple. Twelve-gram charges of 0.8 per cent sulphur-metal and 5-gram charges of slag were subjected to heating for 30 min. at a prescribed temperature. The charges were analyzed for sulphur content. For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal. Six slag and metal charges were made coincidentally in 5/8in. holes in a section of an electrode graphite rod. One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors. For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant. Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO. Slags with Magnesium Oxide Constant 15 Per cent Mg0.—The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SiO2, 5 to 27 per cent A1203 and 24 to 53 per cent CaO. Variation in composition has been in steps of 2 per cent over much of the area. Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered in steps of 4 per cent and even

Jan 1, 1938

By W. F. Holbrook

In a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO. In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 per cent MgO slags over the range 1475' to 1525' C. is included. The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple. Twelve-gram charges of 0.8 per cent sulphur-metal and 5-gram charges of slag were subjected to heating for 30 min. at a prescribed temperature. The charges were analyzed for sulphur content. For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal. Six slag and metal charges were made coincidentally in 5/8in. holes in a section of an electrode graphite rod. One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors. For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant. Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO. Slags with Magnesium Oxide Constant 15 Per cent Mg0.—The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SiO2, 5 to 27 per cent A1203 and 24 to 53 per cent CaO. Variation in composition has been in steps of 2 per cent over much of the area. Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered in steps of 4 per cent and even

Jan 1, 1938

By W. F. Holbrook

IN a previous paper1 a method for the measurement of the comparative desulphurizing power of slags was described and data were presented covering the range of likely slags containing up to 10 per cent MgO In the present work the range is extended to include slags containing up to 20 per cent MgO, and the effect of temperature on 5 per cent and 15 pen cent MgO slags over the range 1475° to 1525° C is included The method used was that described in the previous paper except that some of the temperature measurements were made with a noble-metal thermocouple instead of a tungsten-graphite thermocouple Twelve-gram charges of 0 8 per cent sulphur-metal and 5-gram charge-, of slag were subjected to heating for 30 nun at a prescribed temperature The charges were analyzed for sulphur content For purposes of comparison, desulphurizing power is defined as the ratio of the percentage of sulphur found in the slag to that found in the metal Six slag and metal charges were made coincidentally in 5/8-in holes in a section of an electrode graphite rod One slag and metal charge was used as a control by means of which adjustment in the desulphurization value could be made for small variations in temperature and other factors For convenient presentation of the data, the slags are arranged in groups in each of which one of the four main slag components is constant Thus, the 15 per cent MgO slags are presented separately from those containing 20 per cent MgO SLAGS WITH MAGNESIUM OXIDE CONSTANT 15 Per cent MgO -The data on slags containing 15 per cent MgO cover a composition range of 24 to 50 per cent SI02, 5 to 27 per cent A1203 and 24 to 53 per cent CaO Variation in composition has been in steps of 2 per cent over much of the area Because the change in desulphurization power is generally gradual with gradual change in composition, certain sections have been covered m steps of 4I per cent and even

Jan 1, 1938

By E. W. Cawthorne, R. I. Jaffee, C. M. Craighead

SOLUTION of a solid metal or alloy in a molten metal bath is used daily in melting operations, extractive metallurgical processes, and in brazing. It is generally recognized that temperature, time, agitation, and the composition of the solute metal and the solvent bath all affect solution rate. However, there is little information available in the literature on the kinetics of the process or the relative effect that these variables have on solution rate. In connection with an aluminum brazing study, data on the solution of aluminum in an A1-Si* bath to promote rapid solidification. The chemical analyses were made on drillings taken from the cast plates. The results of this work are listed in Table I. The thermal-analysis data were obtained on 200 gram samples cooled at approximately 1.5" per min. A calibrated chromel-alumel couple was used. The thermal arrests were recorded autographically on a General Electric photoelectric potentiometer recorder. The instrument was calibrated to 22.5 pct. The thermal emf was bucked with a Leeds and Northrup semiprecision potentiometer so that 1 mv represented the full scale of the GE recorder. Referring to Table I, it will be noted that the analytical results tend to be lower than the intended compositions by about 0.3 pct Si in the higher ranges. In view of the known difficulties in obtaining accurate silicon determinations by wet analysis when the silicon content is high and in view of the care that was employed in weighing and preparing the alloys, the intended compositions are believed to be more accurate than the analyses. Furthermore, when the thermal-arrest data are plotted against the intended compositions, a smooth curve is obtained, as shown in Fig. 1. This is not the case when the data are plotted against the analytical results. It will be noted from Table I that the 12.5 pct Si alloy (melt 4) showed a primary arrest at 577.6"C and the eutectic at 576.l°C. The metallographic examination of this chill-cast plate sample showed a small amount of primary silicon. These results, Fig. 1, place the eutectic at slightly less than 12.5 pct Si and are in rather good agreement with the unpublished Hanford data. In all of the subsequent work, the composition of the A1-Si dipping baths was determined by thermal analysis (spread between the primary arrest and the eutectic temperature) employing 12.5 pct Si and 577.2 °C as the composition and temperature of the eutectic. Material Preparation and Selection of the Techniques: At the beginning of this work, it was anticipated that, owing to oxide film present on the surface of the aluminum, difficulty would be encountered in obtaining rapid uniform wetting of aluminum specimens dipped in the A1-Si bath. The following etchants were investigated as possible methods of providing a thin uniform oxide film on the specimen surface: 1—phosphoric acid (H³O4), 2—fluoboric acid (HBFI), 3—sodium hydroxide (NaOH), and 4—hydrofluoric acid (HF). Tests with sheet .specimens (2x½x0.06 in.) of 2s aluminum prepared with these etchants indicated that the fast uniform wetting required for this work could not be obtained if any oxide film existed on the specimen surface. Tests were then conducted by dipping similar specimens etched in 5 pct NaOH and given a thin

Jan 1, 1956

By J. Spotts McDowell

Preparation and Use.-Magnesite is an important refractory in open-hearth, heating, and electric furnaces for steel-making and in many of those employed in the metallurgy of copper and lead. It is sold in the form of brick, finely ground "furnace magnesite" for brick-laying, and dead-burned grains for making and repairing furnace bottoms. The latter are a mixture of granules varying in size from pieces of about 5/8 in. (1.6 cm.) diameter to very fine but sandy particles. Dead-burned magnesite results from calcining 'the crude or lightly burned mineral at a temperature that will not merely drive off practically all the CO2, but will also cause sintering of the particles. During this process the pieces shrink considerably and become hard, dense, and inert to atmospheric moisture and C02; under-burned material, on the other hand, will hydrate on exposure to the air. A small percentage of ferric oxide seems to be necessary for the production of a satisfactory sinter; from 4.5 to 8 per cent. in the dead-burned grains is considered the most desirable amount. Dolomite has been little used for brick-making in the United States, but it is prepared for use in the granular condition calcined or "double-burned" and is the principal ingredient of several materials offered for sale under various trade names for refractory purposes. Dolomitic refractories are almost wholly confined to the open-hearth and electric furnaces, where they are used for fettling and as substitutes for magnesite. Much more magnesite and dolomite are used for basic open-hearth steel-making than for all other refractory purposes. The hearth of the furnace is usually built up of magnesite brick and dead-burned grain magnesite so laid that the brick base is protected by a working bottom of the granular material. The latter is sintered into place in layers 1 to 2 in. (2.5 to 5 cm.) thick to a total depth of 12 to 18 in. (30 to 45 cm.) at the center of the furnace. After each heat, burned dolomite is thrown against the banks as high as it will stick, and all holes in the bottom are filled. At most plants such holes, at the end of each week, are also

Jan 2, 1919

By J. C. Jr. Vaughan

ALTHOUGH a considerable amount of practical importance attaches to systems involving gases and molten metals, little is known regarding the effects of alloy elements upon the solubility of gases in liquid iron. The solubilities of hydrogen1 and nitrogen2,3 in pure liquid iron are known and it has been shown that small amounts of silicon and aluminum3 exert only a small effect upon the solubility of nitrogen but greatly increase its rate of solution. This paper presents the results of a study of the Solubility Of nitrogen, at pressures approximately one atmosphere, in molten iron containing up to 1.5.5 per cent silicon.

Jan 1, 1939

By Walter Miller

ALTHOUGH confident of its ability to meet any demands which may be made, the petroleum refining industry is not complacent about the situation and realizes that the quantities of petroleum products to be furnished are so enormous and so far beyond what was previously estimated that the full co-operative effort of the industry must be exerted. Establishment by the President in May of the Office of Petroleum Coordinator for Defense with Secretary of the Interior Ickes at its head, plus the formation of the Petroleum Industry Council for Defense, in November, provide the channels for united endeavor within the industry and the means for gearing that endeavor within the industry and the means for gearing that endeavor in full harmony with the nation?s needs. Great strides have been made and a rapid understanding of the situation and the magnitude of the task is being attained by all concerned.

Jan 1, 1942

Jan 1, 1910

By E. H. Jr. Dix

OF all the alloying elements used in commercial aluminum alloys, copper stands out as by far the most important, and it is perhaps for this reason that the constitution of the aluminum-copper system has received the attention of a number of experimenters covering a period of approximately 20 years. It would be expected that during this time the equilibrium relations had been thoroughly and exactly worked out. In a general way this is true, but there is a surprising lack of agreement in the details of the high aluminum end of the diagram, particularly in regard to the solid solubility of copper in aluminum, which has been given variously as 2 per cent. to 5 per cent. at the eutectic temperature. The importance of this is much greater than might at first appear to one unfamiliar with modern commercial aluminum alloys. This is true because, with one exception, the susceptibility of the strong alloys to heat treatment depends, in part at least, upon the solid solubility relations of copper in aluminum. In 1919, Merica, Waltenberg, and Freeman1 published the first detailed information on these solubility relations. They found that the solubility of copper decreases with falling temperature from about 4 per cent. at 5.25° C. to about 1 per cent. at 300° C. and is apparently still diminishing at lower temperatures. In 1921 there was published a brief account of the results obtained in the National Physical Laboratory, Teddington, England.2 This laboratory, however, reported that 5 per cent. of copper is soluble in aluminum at 540° C., and that this amount decreases to about 3 per cent. at 20° C.

Jan 2, 1926

By Donald C. Myntti

INTRODUCTION A major segment in a successful heavy equipment maintenance and repair program is the provision of well-laid out and well-equipped shop and service facilities The facilities described here will be those required for a large, high tonnage hard rock open pit mine utilizing rotary drills, shovels, haulage trucks, support equipment, and service trucks. The term support equipment covers the equipment required to support the drill, shovel, and truck operations, these are crawler tractors, road graders, front-end loaders, water trucks, rollers, rubber-tired tractors, etc. Service trucks are the automotive type consisting of rubber-tired over-the- road equipment. The primary structures generally involved in the total maintenance effort are as follows. (1) the main shop with an attached warehouse (the structure could also house the tire and lube shops plus the equipment cleaning stalls), (2) a service station with bulk petroleum product storage tanks, (3) a heating plant, (4) a security station (lf this is a corporate requirement), (5) operating department and employee assembly buildings, and (6) an electrical substation. Under certain conditions, many of these facilities with the exception of the substation could be combined In one or several structures. This arrangement could have a great advantage especially in areas where the heating of the structures is extremely critical.

Jan 1, 1979

By Wm. A. Haven

As soon as the likelihood of American participation in the war was established, and in spite of the fact that we can produce almost as much as all other countries combined, the demand for prompt deliveries of iron and steel products from American factories began to exceed their utmost capacity, and, after fifteen months of practically full operation, has continued to do so. Therefore, it would seem worth while to review some of the aspects of the supply and demand for steel as well as the efforts that are being made to bring them into balance. It is still being debated as to whether the situation should be defined as a real shortage that will persist through the emergency period or as a temporary one than can be relieved by less drastic measures than a Government-sponsored program of expanding existing plants and building new ones.

Jan 1, 1942

By H. Sigurdson, C. H. Moore

Extensive studies have been carried out on electric furnace and blast furnace slags obtained in the winning of iron from its ores. These slags normally consist of elements of the gangue minerals present in the ores, as well as the added flux materials. In consequence, melts of CaO, MgO, Al2O3 and SiO2 can be considered as representing typical slag compositions. When a slag of this composition cools, it usually crystallizes according to predictions possible from an equilibrium diagram of these constituents, providing the melt is not undercooled to form glass. The melt is either viscous or fluid, depending upon the ratio of binary cations to silica, and crystallizes easily or forms a glass for the same reasons. If the melt is not overheated so that carbides of the metal components of the slag are formed and if the composition of the slag is so adjusted that it has a high fluidity, liquid equilibrium is attained and the slag can be held in a liquid state for extended periods of time. Upon tapping, the slag crystallizes into minerals, the type and proportion of which are determined by the melt composition. Since equilibrium is attained, the holding period is not critical. In melts containing a large increment of titanium, however, the normal slag procedures are not applicable. Titanium, as one of the atomic transition elements, is, at elevated temperatures, capable of being reduced to form metalloid compounds much more readily than the refractory oxides present in normal slags. In consequence, an oxide melt containing titanium never reaches equilibrium in a reducing environment, but continues to shift its composition until cooled. If melts of this nature are cooled and samples submitted to metal-lographic and X ray analysis the course of reaction and crystallization in this type of slag can be determined. Preparation of Slag The slags investigated fell into the system CaO-MgO-TiO2-Al2O3-SiO2 and were produced from ilmenite ores reduced by carbon in an electric furnace. Since the equilibrium series1 and the laboratory smelting of ilmenite2 are described in two of the accompanying papers, detailed description of the smelting procedure is not required here. However, certain essentials must be mentioned. Two types of melts were used to produce slags studied in this investigation. The first series of smelts made to determine proper flux addition were produced in a 4 lb Ajax induction furnace. The charge, consisting of ore with the proper flux addition, was heated in a graphite crucible until fluid, held fluid for a sufficient time period to obtain 1-5 pct FeO content, and poured. Because of the small size of the charge only the final sample of these melts could be examined. In the melts made in the 50 lb arc furnace, however, grab samples taken at 10 min. intervals between time of initial melting and final pouring were available for examination. These samples allowed a much clearer picture of the course of reaction and crystallization. amounts of ferrous oxide and reduced titanium compounds is opaque to transmitted light. Therefore, all petro-graphic studies had to be made on polished slag sections. A representative sample of slag was cut or broken, mounted in a thermosetting plastic, ground flat using 400 grit silicon carbide, the coarse scratches removed with 600 grit silicon carbide and polished on billiard cloth using levigated alumina. Rouge was avoided because of the entrainment of the red particles in pores in the slag, causing a possible confusion with some of the mineral phases. In order to prevent sample projection above the plastic surface red bakelite was used to hold the sample, and backed up with clear lucite. In this manner sample labels could be permanently retained in the mounting. The polished samples were examined on a Bausch and Lomb metallograph at magnifications of 250 X, 500 X, 1000 X and 1800 X. The instrument was equipped for examination of specimens under bright field illumination and with crossed nicols. A magenta tint plate to aid in color tone differentiation was also used. Petrology of Slags In order to determine the composition and mineral relatinos of a previously unreported system petrologically, it is essential that the starting composition, reaction temperature and final composition be known. The chemical composition of the ilmenite ore used in these smelts is given in Table 1, and the complete analysis of a typical high titanium, low iron slag is given in Table 2. In the winning of TiO2 from ilmenite by a smelting process it is necessary to produce a slag which will melt at an economically feasible temperature, remain molten as the iron is removed by reduction, be fluid enough to be readily removed from the furnace, contain a high percentage of TiO2 and a low percentage of reduced titanium com-

Jan 1, 1950

By Oliver Bowles

GLASS razor blades, glass chairs, and marble window panes attest that creative genius was still active in 1935. Many less striking, though doubtless more important, developments are to be recorded for the nonmetallic mineral industries, and not the least of them is the establishment of an Industrial Minerals Division in the A.I.M.E. under the able leadership of Samuel H. Dolbear, Chairman. Thus the nonmetallics are rightly granted equal dignity with metals and fuels in the category of mineral industries. The brief review of progress that follows merely touches the fringe of important developments in this broad field.

Jan 1, 1936