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Jan 1, 1894

By Wilbur C. Helt, Joseph J. Yancik

Throughout the history of mankind, the principal use of coal has been to produce heat through combustion. The heat is used in many ways: to warm air space for our comfort; to provide heat or energy to power industrial processes, such as cement and steel production ; and to produce electricity. Because it is our nation's most abundant fossil energy fuel, coal in the late 20th century is on the threshold of becoming a significant source for synthetic liquids and gas energy fuels for this country. This is made possible by conversion processes which can change solid coal into various synthetic gases and liquids. These coal-derived fuels are nearly identical to the processed fuels and chemicals provided by natural gas and crude oils, which presently provide almost all the petrochemical feedstocks and energy fuels needed for the residential, light commercial, and transportation markets. A revolution is beginning to take place, not only in the United States, but in many other countries with a return to a coal-based energy economy. Also, new combustion and conversion technologies which are compatible with national health and environmental goals are rapidly emerging. These technologies will allow coal's use to be expanded not only in its traditional markets, but also to supply markets held by natural gas and crude oil. With the worldwide decline in natural gas and crude oil reserves, coal is being looked upon to meet the energy demand. Because of these new coal conversion technologies, coal will no longer be only a combustion fuel, but a valuable raw material for production of a variety of clean fuels and chemicals. MARKETS FOR COAL: PAST AND FUTURE A simplified diagram of the marketing network for coal is shown in Fig. 1. As shown in this figure, coal is transported to its traditional

Jan 1, 1981

By J. J. Arps

n approach to the study of the electrical properlies of drilling muds, their cakes and their filtrates was made by treating the drilling fluid as a porous medium. Lluring this study it was found that the weight pararneter was omitted from previous investigations on electrical properties. Patnode in 1949 made a similar approach to ,his investigation. His work showed that there was a variation of resistivity relationships with per cent Puid present in a given suspension. This present study ex-tends Patnode's investigation to one in terms of the solids fraction of the drilling fluids. Previous investigations were made on low weight muds where the effect of the rolids fraction was obscured. The following equationr were fitted to data taken from 94 field muds and 47 laboratory muds (see Tables I and 2). The parameter, C, is a complex function of the solidr content, or mud weight, of a drilling fluid. It was also found that for all drilling muds examined. A nomograph is presented combining Eqs. I and 2. INTRODUCTION It is generally recognized that the materials present in drilling muds affect the relationship between mud filtrate and mud resistivities. However, most electric log interpretations proceed with the assumption that the mud resistivity and temperature are the only important parameters needed to obtain a filtrate resistivity or a mud cake resistivity. Lamont1 suggests that only average relationships exist between mud cake, mud filtrate and mud resistivities. He indicates that there is limited accuracy when these intercorrelated factors are used since no other measure-able variable is apparent. A previous paper by Patnode indicates that drilling fluids may be considered to be a system of fluids in solid particles which may be correlated electrically in a manner similar to rock solids. 1 he equation for the resistivity factor. F = (per cent fluid) is satisfied for a given clay type in water, but the value of m varies as different materials are used in the water. The resistivity factor is not constant for a given amount of clay. As is suspected it varies as the solids fraction conducts electrical current. Since both weighting material and clay solids are present in commonly used drilling fluids, it is expected that both materials contribute to the variation of the m factor in Eq. 3. An extension of Patnode's work is presented in this paper to show some of the interrelations which exist between the resistivities of mud cake, mud filtrate and mud. Use of these data enable a more accurate calculation of mud filtrate and mud cake resistivities if only the mud resistivity and weight are measured. EXPERIMENTAL The measurements of mud weight, fluid and solids resistivity, alkalinity, and chloride content of mud samples were made in this research. Mud samples representing drilling fluids from 94 Louisiana and Texas wells (Table 1) and 47 laboratory-constructed systems (Table 2) were used in the experimentation. The measurements of the mud properties were made both in the field and in the laboratory. The tests on the properties of weight, alkalinity and chloride ion were standard tests as described by API specifications. The resistivity measuring devices were constructed in the laboratory for this study. For details on the resistivity equipment see Fig. 1. The fluid cell

By David Scott

THE MOGOLLON mining district, New Mexico, has received little public attention, although for 15 years it has been the leading silver producer of the state; it is situated in a region remote from the principal lines of travel, and its activities have usually been limited to the operations of two or three companies. The value of the total production of the district in the 44 years of its history has been estimated at $15,000,000. For the years 1904 to 1917, inclusive, the output was: gold, $4,370,000; silver, 10,042,000 oz.; copper, 874,862 lb.; total value, approximately. $10,500,000. In 1913 the district contributed 80 per cent. of the total silver production of New Mexico, but in 1917 only 41 per cent., due to serious interruption in the operations of the leading producer. Since 1914 the silver output has diminished one-half, and the present high value of silver is nearly offset by the increase in cost of production. The output of gold has rarely exceeded 35 per cent, of the total for New Mexico. The ratio of silver to gold, by weight, has averaged 46:1 based on the whole output of the district. LOCATION AND TOPOGRAPHY The town of Mogollon is 75 mi. (121 km.) by a poorly located highway from the nearest railroad terminals, at Silver City and Tyrone. All supplies are transported by motor trucks and teams. The area, sometimes called the Cooney Mining District, lies on the western flank of the Mogollon Mountains, which occupy the western part of Socorro County. The elevations drop steeply on the west to the valley of the San Francisco River, adjacent to the Arizona boundary. The topography is very rugged, the whole area being sharply dissected; deep canyons with steep gradients and rugged walls are characteristic of the whole western-slope of the Mogollon Range. The main canyons run east and west, and usually maintain a flow of water during the entire year. As would be expected in a region of such deep dissection, the

Jan 2, 1920

By J. S. Diller

In 1827, chromite was discovered near Baltimore by Isaac Tyson, Jr., who initiated the mining of chrome ore an:! later (1845) .the manufacture of chromium compounds in this country. From 1828 to about 1860 the United States, supplanting Russia, supplied chromite for most of the world. Chrome deposits were found also in California, and the Tyson Company shipped ore to Philadelphia by way of Cape Horn. In 1848, J. Lawrence Smith, an American in the employ of the Porte, discovered large bodies of chromite in Asia Minor. They were developed in 1865 and became the chief source of the world's supply for a number of years. The discovery of the large high-grade bodies in New Caledonia, and later in Rhodesia, with other foreign sources, gives at present an abundant supply for all demands. For a number of years before the great war, the United States produced only a few hundred tons of chromite annually, for local use, but during the war the demand for domestic ore resulted in a production of more than 82,000 long tons of crude ore in 1918, and it was demonstrated that the United States has reserve deposits equal to a war demand of several years' duration. Now that the war is over, the country is conserving its domestic supplies by employing higher-grade but cheaper ore from foreign countries. ChromiUm-bearing Minerals Oxides: Chromite-—chromic iron ore................ FeO.Cr2O3 Picotite—chromic iron ore................. (MgFe)O.(Al,Cr) Chromates: Crocoite—lead chromate................... PbCrO4 Phoenicochroite—basic lead ohromite........ 3PbO.2CrO3 Vauquelinite—phospho-chromate of lead..... 2(PbCu)CrOd.(PbCu)3P2O8 Sulfates: Redingtonite—hydrous chromium sulfate.... Knoxvillitel—hydrous basic sulfate of chromium.............................. Daubreelite-—iron-chromium sulfide (known in meteorites only)...................... FeS.Cr2S3

Jan 1, 1920

By I. J. Polmear

Earlier work revealed that small amounts of silver (< 0,l at. pct) may exert a marked effect on the structure and aging characteristics of certain a1loys based on the Al-Zn-Mg system. Silver additions have now been made to other age-hardening aluminum alloys, and significant effects have been observed in the Al-Mg system and in several Al-Cu-Mg and Al-Mg-Si alloys. Similarities exist between the behavior of alloys from all four systems, notably that in each case silver stimulates nucleation of an intermediate precipitate which forms when the alloys are aged in the medium temperature range (-120" to 220°C). The mechanism for this effect is uncer- IT has been shown that small additions of silver (<0.1 at. pct) may have a marked effect on the structure and age-hardening characteristics of tain although it is suggested it originates in a preferred affinity between magnesium and silver atoms. There is evidence to indicate that the effects of silver are unique to that element. It is suggested that silver atoms interact with vacancies during low-temperature aging of Al-4 pct Cu and certain Al-Cu-Mg alloys. Silver had little effect on Al-8 pct Zn aged at any temperature. Preliminary observations indicate that silver may have interesting effects on the strength properties of Al-Mg alloys, md a the commercial Al-Cu-Mg alloys designated as 2024 and 2618. many alloys based on the Al-Zn-Mg* system.1"&apos;*

Jan 1, 1964

By Joseph E. Pogue

The writer visited the Muzo emerald mines in July, 1915, and spent six days in their study. This paper embodies the results of his observations, plus information personally communicated by Robert Scheibe, Professor of Geology in the Mining Academy of Berlin, who at the time of the visit was completing a detailed field investigation of nearly a year&apos;s duration of the emerald deposits of Colombia. An elaborate account of this valuable work may be expected at a future date from the pen of Professor Scheibe.

Jan 1, 1917

By Robert L. Dean, Michael Hoch, Samuel M. Wolosin, Chung K. Hwu

The general shape of the 1450°C isotherm of the Ti-TiO-ZrO2-Zr region was evaluated from the surrounding binary phase diagrams and from thermo-dynamic data on the metal-oxygen binaries. The phase boundaries were accurately determined using X-ray and metallographic techniques. At 1450°C the system shows a large bcc ß field, which extends from the two metal-oxygen binary systems as a Gaussian error function, and is stable up to 30 at. pct 0 when Ti and Zr are present in equal amounts. At higher O Concentrations, the ß field is in equilibrium with t-ZrO . The following four regions, with three solid phases, are present: two a ß t-ZrO,, a TW t-ZrO,, and TiO t-ZrO2 c-ZrO2. On cooling the ß phase transforms into the a phase, going through the w transition phase. The isotherm at 1500°C for the region TiO-TiO,-ZrO, was obtained by using X-ray diffraction. At 1500°C a large c-ZrOz region is present as well as a large two-phase field, Ti0 c-ZrO,. The following regions, with three solid phases in equilibrium, were found These regions are relatively small. The solidus and liquidus relationships were determined by observing samples suspended in a tungsten crucible by means of a fine tungsten wire and heated in vacuum. Eleven univariant points were found. C-ZrO, decomposes through a peritectic reaction into liquid t-ZrO2. The activities of Ti and TiO in the TiO t-ZrOz and in the two a ß t-ZrO regions were measured using the Knudsen effusion method. In the a TiO t-ZrO, region the activities of Ti and Ti are the same, as in the a — Ti TiO binary. In the two a t-ZrO, regions, the Ti activity is high and the Ti0 activity very low, although all phases present contain at least 30 at. pct 0. This indicates a short-range order in the solid phases, Zr atoms being preferentially surrounded by 0. 1 HE system Ti-Zr-0 is of interest because of the wide ranges of solid solubility exhibited by the boundary systems; as titanium and zirconium both belong to the same group of the periodic table, large single-phase regions should occur within the system, with a great variation of properties (as the composition changes within the single-phase region). Furthermore, the possibility of modifying ZrO, to make it a more usable refractory by the addition of other metals makes this system also of interest. Because of the high affinity of titanium and zirconium for oxygen, the oxygen partial pressure is very low at all compositions; thus, there exists a ternary metal-metal-oxygen system in which the oxygen pressure is not an important variable, so long as it is low enough. When a sample is heated in vacuum to a temperature high enough for vaporization to occur, the vapor phase will consist of metal and metal-oxide gas, the oxygen concentration being very low. The phase relationships in the surrounding binary systems have already been reported in the literature; therefore, the study of the ternary diagram

Jan 1, 1962

By Mark Malamphy

THE occurrence of outcrops of bituminous schists and sandstones impregnated with heavy asphaltic petroleum first directed attention to the Sao Pedro area as a possible source of commercial production of petroleum. Since 1920, more than 20 wells have been drilled in this area. The discovery of oil shows and small quantities of natural gas in some of the early wells led to the continuation of drilling in the hope that more important findings would result. During the early part of 1934, detailed magnetometer observations were made in this area, and a con-siderable number of torsion balance stations were occupied. The results of these geophysical observations help considerably to clarify the structure of the area and the very considerable amount of geologic information available makes possible a much more exact interpretation of geo-physical anomalies. In presenting the results of these observations, and interpretation of the geophysical data, certain actual case problems are included; i.e., geophysical anomalies due to anomalous masses of which the forms and positions are more or less known. Although anomalies due to igneous intrusions are probably more important to geophysicists in Brazil than in other countries, these data have a certain interest for all geophysicists, particularly because they were obtained in the south magnetic hemisphere, where the lines of magnetic force are directed upward, and in a region of moderately low inclination. This is considered as a geological-geophysical problem, and only passing mention will be given to the petroleum possibilities of the area.

Jan 1, 1936

By M. F. Hawkes

Austenite grain size has long been recognized by metallurgists as an important property of steels because of its influence on toughness, hardenability, ma-chinability and creep strength. Much research has been carried out on wrought steels to develop methods for disclosing austenite grain size, and to, provide knowledge of the grain-size characteristics of steels produced and heat-treated in various ways. Much less work in these fields has been done on steel castings; partly because, owing to the variable and complex microstruc-tures of cast steels, it is frequently very difficult to obtain results that are not questionable. The object of this investigation, therefore, was to establish, for a wide variety of carbon and alloy cast steels, suitable methods for disclosing austenite grain size and some knowledge of the grain-size variations to be expected. The steel foundryman is interested in austenite grain size at two different stages in the manufacture of his products; one is just after the steel is cast, and the other is after any reheating operation carried out above the critical temperature range. In both, it must always be kept in mind that the grain size being sought is actually a previous austenite grain size, and that the austenite no longer exists once the steel has cooled to room temperature. The prob-lem of the investigator is always to use evidence obtained from the structure at room temperature to deduce this previous austenite grain size, which was established the last time the steel existed at a temperature above the critical range. Since most steel castings today are at least annealed or normalized, the measurement of austenite grain size established by heat-treatment will he considered first. More than 50 commercially produced cast steels rcpresenting a wide variety of compositions and melting practices were used in the study. For each steel, grain-size determinations were made after each of three widely varying heat-treating schedules namely, one hour at I550&apos;F, one hour at I700°F, and six hours at 1700 F. The list of steels and results obtained on them will be found in the appendix. (See page 530.) A discussion of the knowledge gained on the applicability of various test methods and on grain-size characteristics of cast steels in general follows. MEASUREMENT OF AUSTENITE GRAIN SIZE ESTABLISHED BY HEAT TREATMENT Methods Suitable foR Determining Austenite Grain Size after Heat-treatment at Ordinary Temperatures and Times It was desired, as one of the results of this investigation, to be able to recommend to steel foundries a method, or methods, of disclosing grain size best suited to accurate

Jan 1, 1948

By M. F. Hawkes

Austenite grain size has long been recognized by metallurgists as an important property of steels because of its influence on toughness, hardenability, ma-chinability and creep strength. Much research has been carried out on wrought steels to develop methods for disclosing austenite grain size, and to, provide knowledge of the grain-size characteristics of steels produced and heat-treated in various ways. Much less work in these fields has been done on steel castings; partly because, owing to the variable and complex microstruc-tures of cast steels, it is frequently very difficult to obtain results that are not questionable. The object of this investigation, therefore, was to establish, for a wide variety of carbon and alloy cast steels, suitable methods for disclosing austenite grain size and some knowledge of the grain-size variations to be expected. The steel foundryman is interested in austenite grain size at two different stages in the manufacture of his products; one is just after the steel is cast, and the other is after any reheating operation carried out above the critical temperature range. In both, it must always be kept in mind that the grain size being sought is actually a previous austenite grain size, and that the austenite no longer exists once the steel has cooled to room temperature. The prob-lem of the investigator is always to use evidence obtained from the structure at room temperature to deduce this previous austenite grain size, which was established the last time the steel existed at a temperature above the critical range. Since most steel castings today are at least annealed or normalized, the measurement of austenite grain size established by heat-treatment will he considered first. More than 50 commercially produced cast steels rcpresenting a wide variety of compositions and melting practices were used in the study. For each steel, grain-size determinations were made after each of three widely varying heat-treating schedules namely, one hour at I550&apos;F, one hour at I700°F, and six hours at 1700 F. The list of steels and results obtained on them will be found in the appendix. (See page 530.) A discussion of the knowledge gained on the applicability of various test methods and on grain-size characteristics of cast steels in general follows. MEASUREMENT OF AUSTENITE GRAIN SIZE ESTABLISHED BY HEAT TREATMENT Methods Suitable foR Determining Austenite Grain Size after Heat-treatment at Ordinary Temperatures and Times It was desired, as one of the results of this investigation, to be able to recommend to steel foundries a method, or methods, of disclosing grain size best suited to accurate

Jan 1, 1948

By Charles White Merrill

Mankind&apos;s progress is measured in minerals. Man&apos;s emergence from prehistory is marked by passage through a Stone Age and a Bronze Age and into the present era, sometimes called the Iron Age or the Age of Metals. With the evolution of civilization and the development of a modem industrial economy, minerals become more and more important. Structures, roads, and machines are built largely of minerals; the energy to heat the structures and to drive the machines is mostly mineral; agricultural fertility is maintained by mineral fertilizers and water; and military strength is provided by fortresses, armaments, and munitions, largely of mineral origin. Thus in the material world, in the productivity of the economy, access to minerals has paramount importance. Every evidence indicates increasing dependence on minerals in the modem economy, particularly on the mineral fuels as energy sources to provide the power base for advancing industrialization. Both the total and the per capita consumption of almost every mineral is increasing in the industrialized nations. Moreover, nations with predominantly agrarian economies call themselves underdeveloped and universally strive to industrialize. Most mineral consumption trends in the more advanced economies have been greatly exceeding population growth-which itself has been advancing at an accelerating rate--and sometimes have surpassed the growth in real income. Some minerals have only recently been adopted or grown to importance in use. Titanium as a metal appeared as a commercial product only in 1948, and even coal seriously displaced wood as a source of heat less than two centuries ago. On the other hand, minerals have always played an important role in construction. The prehistoric megaliths that form the dolmens of Salisbury Plain are stone; the pyramids are andesite faced with limestone; and many other ancient structures are built of mineral materials. In modem times the whole course of architecture has been redirected by new building materials, mostly mineral. Most conspicuous is the sky-

Jan 1, 1959

By M. Earl Volin, M. Adnan Goksel

The hydro thermal agglomerating process described (U.S. Pat. No. 3,235,371, 1966)* is different from the cotzventional high-temperature processes. Green pellets or briquettes made with mixtures of moist iron-ore concen- trates and burned or hydrated lime fines are hardened in an azttoclave at 198°C and under steam pressure for 112 to 5 hr, with or without previous drying. Under the neutral conditiotzs, oxidation of magnetite does not occur as in the conventional processes. The resulting azzlomerates-- are hard and resistant to abrasion and weathering, and they do not disintegrate in the Under test. The equipment required for the process is not complicated, and favorable operating costs are projected because of the low temperamre and efficient heat recuperation. A low capital investment makes the process attractive even when the annual pellet production is below a million tons.

Jan 1, 1970

By R. M. N. Pelloux

This study of aluminum-copper alloys had two aims: 1) To determine the effect of the amount and distribution of a second phase, CuAl2, on the creep-rupture strength, ductility, and fracture characteristics of the alloys. The work of Gemmell and grant&apos; on single-phase aluminum-copper alloys provided a basis for the present study. 2) To attempt to provide a relation between the microstructure and strength of two-phase alloys deformed at comparatively high temperatures (greater than 0.45 T,). The creep behavior of the two-phase magnesium alloys Mg;Ce and Mg-A1, has been treated by Roberts. 9 In work reported by Sully and Hardy4 and by Underwood, Marsh, and Manning~ on A1-Cu two-phase alloys, and also in a portion of the work of Gemmell and grant,&apos; aging took place during the creep tests. &apos;In the present work, overaged aluminum-copper alloys were subjected to creep deformation at two temperatures, 500 and 700OF. The overaging treatments to produce the precipitate dispersions were performed prior to the test, at temperatures which were the same as the ultimate respective test temperatures. Hence, the present study is concerned with the creep behavior of stable (in contrast to "underaged") two-phase A1-Cu alloys, i.e., alloys in which no depletion of the solid-solution matrix occurred during: creep. MATERIALS AND PROCEDURE A 2 and a 3 pct Cu alloy, supplied by Alcoa, were studied; Table I shows the compositions. The grain size of the specimens, 0.9 to 1.0 mm, was achieved by annealing the machined test bars for 2 hr at 1000°F, followed by furnace-cooling to 900°F, and homogenizing for 4 hr. Both compositions are in the single-phase condition at 900°F. Two types of overaged dispersions, termed "over-aged I" and "overaged 11" were prepared after the grain size and the homogenization anneals. The overaged I alloys were prepared by quenching to room temperature after homogenization, aging at either 500&apos; or 700°F for 72 hr, and air-cooling to room temperature. The overaged I1 alloys were prepared by furnace-cooling after homogenization, to either 500&apos; or 700°F, and holding at the necessary temperature for 72 hr. The times for furnace-cooling from 900°F to 700° and 500°F were, respectively, about 2 and 3.5 hr. The structures of the A1-2 pct Cu alloys are shown in Fig. 1 (overaged I) and in Fig. 2 (overaged 11). A comparison of Figs. 1 and 2 shows that in the overaged I alloys the precipitate particles along the grain boundaries are much more closely spaced and the grain boundaries are straighter than they are in the overaged I1 alloys. Further, the particle size and spacing in the grains are smaller than in the overaged I1 alloys. Microstructures of the A1-3 pct Cu alloys have not been shown; the structures of these alloys differed from those of the A1-2 pct Cu alloys only in that the distribution density of the particles was greater. The creep specimens had a gage section 1 in. long with a diameter of 0.155 to 0.195 in. Before testing, specimens were electropolished in a solution of 100 cc glacial acetic acid, and 30 cc of 60 pct perchloric acid, at 40&apos; to 50°F, at 24 v. The specimens were kept refrigerated prior to testing to avoid precipitation at room temperature. Constant stress creep tests were conducted; the load was applied 75 min after heating of the specimens to test temperature had begun. EXPERIMENTAL RESULTS Creep-Rupture—Fig. 3 shows the log stress-log rupture life plotfor the overaged alloys studied, and also for the underaged A1-2 pct Cu alloy.&apos; At 700°F, the stress-rupture life relationship is nearly independent of both the amount of precipitate (i.e., composition) and of the type of overaging treatment (i.e., precipitate dispersion). At 500°F it is apparent that the increase in rupture life that was ex-

Jan 1, 1960

By M. Yoshinuga, S. Watanabe

Some iron ores, sinters and pellets occasionally show abnormal behavior during reduction which makes them undesirable as blast furnace burden. These may be divided into the following three types: (1) decrepitation of iron ore, (2) swelling of iron ore and pellet, (3) size degradation of sinter. In this paper reduction experiments and microscopic examinations were made to clarify the mechanisms and causes of these abnormal phenomena. Decrepitation occurs mainly when compact hematite ores containing small amounts of limonite are heated to about 500°C. Abnormal swelling of ores and pellets is caused by the rapid growth of fibrous metallic iron from the surface of wustite grains during rapid reduction and is fundamentally related to their original microstructure. Size degradation of sinter occurs through the development of cracks in the reduction stage from hematite to magnetite. About 80% of the iron ore used in Japan&apos;s blast furnaces comes from abroad, and the iron and steel industry must import this raw material from distant overseas places at high freight rates. The blast furnace operators, therefore, have made strong efforts to cut costs under these restrictive raw materials conditions by increasing productivity and simultaneously decreasing coke consumption. If, however, a high proportion of the ore burden consists of unsuitable materials furnace irregularities often result, establishing the need for detailed investigations of the basic natures of the ore constituents and their reactions during the reduction process. Recent investigations &apos;-&apos; of various ore burdens suggest that some iron ores, sinters and pellets are occasionally abnormal in appearance and behavior during reduction studies and may prove to be undesirable for use in the blast furnace. In the present study reduction experiments and microscopic observations were made to clarify the causes and the mechanisms of the abnormal behavior observed in some constituents of the burden and their effect on blast furnace performance. REDUCING APPARATUS The four kinds of reducing apparatus used in this investigation were the following: 1. The JIS* (Modified Gakushin&apos;) apparatus shown in Fig. la is most commonly used in Japan to evaluate the reducibility of ores under static conditions. It consists of a stainless steel tube of 60 mm inside diam suspended from a balance. 2. Linder&apos;s Reduction Test apparatus (Fig. lc) has a reducing barrel 130 mm diam and 200 mm long which rotates at 30 rpm. Some modifications were made in test procedures. 3. Gakushin Standard Test apparatus for determining the reducibility of granular ores (Fig. Id) consists of a horizontal silica tube 32 mm diam, 370 mm long and a movable electric furnace which enables rapid heating and cooling of the specimens. 4. The test apparatus for reduction under load (Fig. lb) gives a comprehensive evaluation of the behavior of ores under conditions simulating the static loading and the chemical reduction conditions encountered in. a blast furnace stack. A stainless steel tube of 50 mm diam and a carbon rod of 35 mm diam were used as the sample container and the support for the weight, respectively. In each investigation care was taken to select the most suitable method and apparatus to distinguish the abnormal nature of the ore in question. SIZE DEGRADATION OF SINTER DURING REDUCTION Sinter makes up the major portion of the blast furnace burden and its behavior during reduction should bear a close relationship to the iron productivity. Recently, some of the sinter was found to show serious size degradation during reduction at a relatively low temperature range. Because this phenomenon was thought to be a possible source of furnace irregularities, tests were made to clarify the phenom-

Jan 1, 1969

By A. C. Heath, E. H. Dix

The importance of aluminum-silicon alloys in thc light alloy field is now generally recognized. Where silicon was once considered detrimental to the properties of aluminum, useful alloys now contain as much as 13 per cent. Furthermore, silicon is present as an impurity in aluminum of even the purest grades. Iron is another important impurity in aluminum and likc silicon is found in small quantities in the purest aluminum available today. The manner of occurrence of iron and silicon in commercially pure aluminum and many of its alloys exerts a very pronounced influence upon their properties. The effect of large quantities of iron in aluminum-silicon alloys is so detrimental that it has been found necessary to limit the allowable maximum percentage to as low a figure as is consistent with quantity production and satisfactory physical properties. The intimate relation existing between iron and silicon in aluminurn and alurninum alloys makes necessary a more complete knowledge of this ternary system. This paper is divided into two principal parts, dealing respectively with aluminum-silicon solubility equilibria and the constitution of aluminum-iron-silicon alloys. Part I.—Aluminum-silicon Alloys The early work on this system was largely confined to determining the general form of thc diagram and in this respect the results are in good agreement. Briefly, alulninunl and silicon form a simple eutectifcrous series without compounds. Until recently the solid solubility of silicon in aluminum had not been accurately determined. Ipraenkell (1908) stated that aluminum will retain 0.5 per cent. silicon in solid solu-t&apos;ion. Rosenhain, Archbutt and Hanson2 gave the maximum solubility as about 1.50 per cent. and added that "this solubility docs not appear

By G. Derge, Ling Yang, G. M. Pound

The specific conductance and its temperature dependence were measured over the entire composition range of the molten Cu2S-CuCI system. At a typical temperature of 1200°C, 10 rnol pet of the ionically conducting CuCl reduced the specific conductance from about 77 ohm-lcm-l for pure Cu2S to about 32 ohm -1cm -1, and 50 mol pet CuCl reduced the conductance to that for pure CuCI—about 5 ohm 1cm1. The nature of electrical conduction in molten Cu2S, FeS, CuCI, and mixtures was studied by measuring the current efficiency of electrolysis at about 1100°C. The Cu2S, FeS, and mattes were found to conduct exclusively by electrons, but addition of 1 5 wt pet CUS to Cu2S produces a small amount of electrolysis. Addition of CuCl to Cu2S suppresses electronic conduction, and ionic conduction reaches almost 100 pet at a CuCl concentration of about 50 mol pet. These facts are interpreted in terms of electron energy level diagrams by analogy to the situation in solids. RESULTS of electrical conductivity studies on molten Cu-FeS mattes as a function of composition and temperature have been reported.&apos; The specific conductances ranged from about 100 ohm-&apos; cm-&apos; for pure Cu2S to 1500 ohm-&apos; cm-1 for pure FeS. This is in sharp contrast with the low specific conductance of molten ionic salts for which the transfer of electricity is by migration of ions in the field. In general, these ionically conducting molten salts, such as NaC1, KC1, CuC1, etc., have a specific conductance of the order of magnitude of 5 ohm-&apos; cm-&apos;. It was concluded on the basis of this evidence that molten FeS and Cu,S exhibit electronic conduction. Pure molten FeS has a small negative temperature coefficient of specific conductance, resembling metallic conduction, while pure molten Cu2S has a small positive temperature coefficient, resembling semi-conduction. The molten Cu2S-FeS mattes follow a roughly additive rule of mixtures, both with respect to specific conductance and temperature coefficient. Savelsberg2 has studied the electrolysis of molten Cu2S and Cu2S + FeS. He concluded that while molten Cu2S is an electronic conductor, there is some ionic conduction in molten Cu2S + FeS3 owing to the formation of the molecular compound 2Cu2S.FeS and its dissociation into Cu1 and FeS2-1 ions. The present work does not verify his results. Chipman, Inouye, and Tomlinson" have studied the specific conductance of molten FeO and report a high specific conductance, about 200 ohm-1 cm-1 of the same order of magnitude as that found for molten mattes, and a positive temperature coefficient. They interpret these results in terms of p-type semiconduction in the ionic liquid by analogy to the situation in solid FeO.1 imnad and Derne&apos; detected appreciable ionization in molten FeO by means of electrolytic cell efficiency measurements. In order to verify the conclusion that electrical conduction in molten Cu2S and mattes is electronic, and to gain further insight into the structure of molten sulfides, the following investigations were carried out in the present work: 1) The specific conductance, s of the molten system Cu2S-CuC1 was measured as a function of temperature over the entire composition range. As discussed later, molten CuCl is an ionic substance. It was thought that if molten Cu2S were simply ionic in nature, addition of small amounts of CuCl might not have a catastrophic effect in lowering the high conductance of the Cu2S. On the other hand, if much electronic conduction occurs, addition of the ionic CuCl should have a large effect in destroying the electronic conduction. 2) The electrolytic cell efficiency of the following molten systems was measured at about 1100°C in specially designed cells: Cu3; Cu2S + FeS, 50:50 by wt; FeS; Cu2S + CuS, 15 wt pet; Cu2S + CuC1, 5.9 to 46.4 mol pet; and CuC1. This gives a direct measure of the fraction of current carried by ions in these melts. Further, the cell efficiency, extrapolated to zero ionic current, is given by cell efficiency = (s leasile + s elexstronic). [1] s lucile for molten CulS would be expected to be no greater than that for molten CuC1, whose s lonle is about 5 ohm-&apos; cm-1, as will be seen in the following. u,.,,.,.,.......for molten Cu,S is of the order of 100 ohm-&apos; cm-&apos;.&apos; Thus, a large increase in cell efficiency from 0 to values of 10 to 100 pet upon addition of CuCl to Cu2S would indicate destruction of the electronic conductance. Conductance Measurements Experimental Procedure—The apparatus and experimental method were the same as those described in detail in connection with the study of electrical conduction in molten Cu,S-FeS mattes.&apos; A four terminal conductivity cell and an ac poten-

Jan 1, 1957

By H. Rush Spedden, A. M. Gaudin

IN the belief that a critical study of its operating problems might be a sound investment, the Cuban American Manganese Corporation initiated an ore-treatment research in cooperation with the Massachusetts Institute of Technology One of the early objectives of this research naturally became the relationship of the microscopy of the Cuban ores of the Corporation to their flotation treatment The operations in Cuba have already been described by F S Norcross, Jr 7 and the laboratory study of manganese oxide flotation goes back a number of years 4 Broadly speaking, the difficulties encountered in the flotation of manganese ores are that the consumption of reagents is extremely high, the concentrate contains more silica than is desirable and the tailing losses are relatively high An appreciable betterment on any of these scores would achieve a definite betterment in costs, quantity of minable ores, and quality of product The microscope study discussed in this paper was made on samples from the Quinto mine, from the Ponupo mine, and from mill products at various stages of passage of the ore through the mill The writers have had access to Company records and in particular to the petrographic studies made on thin sections of ore by the late Professors R J Colony and Philip Krieger, of Columbia University They acknowledge their debt to both of these men for the help derived from the reports Manganese oxides are black, friable, smudging It is therefore, very difficult to judge operations by inspection The mineralogy of manganese compounds seems to be confused, and the authors believe that many more minerals have been described than actually exist Much of this difficulty is due to the prevalence of the structural conditions that will be discussed further in this paper, namely, the porosity and the friability of the ores, and the extremely intimate association of minute manganifeous mineral crystals with impurities of various sorts By all odds the most important manganese mineral in Cuba is the one that in this paper is called "psilomelane " The name "psilomelane" has been used in so many different ways that the choice of it for this ore may not be approved by all However, it seems to be the best under the circumstances This mineral accounts for about 97 per cent of the manganese in the ores of the Quinto and Ponupo mines and in the mill feed The remaining odd 3 per cent consists mostly of pyrolusite together with minor amounts of other manganese oxide minerals DESCRIPTION OF PSILOMELANE Aggregate Structure In grains or lumps, psilomelane has a characteristic fibrous appearance and seems

Jan 1, 1942

Schedule of Events

Jan 1, 1977

By N. F. Neumann, A. W. Schlechten

Metal chlorides were formed by reacting metal oxides and calcium chloride; the effect of additions to the reaction mixture was studied. It was found that by use of proper additions, metal chlorides could be prepared from mixtures that were not reactive under ordinary conditions. ManY recent metallurgical developments involve the use of chlorine or chlorides as primary reagents; good examples are found in the production of ductile zirconium and titanium by reduction of their chlorides with magnesium. Various methods of preparing metal chlorides are used and many others have been proposed. Some chlorides are formed by the direct combination of a metal or alloy with chlorine. Other processes react chlorine and metallic oxides; carbon or other reducing agents are usually employed to reduce the metal oxides and so promote chlorination. Metallic chlorides have also been produced by the exchange of chlorine between metal oxides and a chloride, such as sodium chloride. This type of reaction was the basis for the old process of chloride roasting in which metal ores were roasted in the presence of salt. Soluble chlorides thus formed

Jan 1, 1959