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By Thomas A. Wright

No symposium on die-casting could be complete without consideration of the methods of formula and impurity control. No corisideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular. Composition Aluminum.-Aluminum die die castings are expected to conform to the specifications of the Amcrican Society for Testing Materialslt and the Society of Automotive Engineers2. The A.S.T.M. has recognized seven aluminum alloys in Tentative Specification B85-33-T. TWO are straight silicon and the remainder are of the copper-silicon type of which alloys VIII and IX have in addition respectively 2 and 4 per cent of nickel, but unlike the others are not covered by S.A.E. as well. All seven call for rigid control of certain impurities. With the exception of alloy XII,

Jan 1, 1935

By Robin J. Batterham, Dave J. Robinson

The most significant trend in flotation has been the ever-increasing scale of operations. There is, however, doubt that this ongoing trend is enough to maintain the economics against trends such as falling grades, increasing mining costs, pressure on water supply and demand, rising energy demands needed for mineral processing, and a focus on whole of life value and mine legacy issues. We comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in-place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10 to 20 years, but in the meantime the focus is just as likely to be on removal of waste (beneficiation) much earlier in circuits. Either way, mineral processing and flotation as we know it will change significantly. 

By John Randall

It is a fair assumption that the main purpose of any diagram is to present facts to the eye in more convenient form than they could be tabulated in figures, and this implies that a screen diagram should set forth in a convenient and familiar form certain facts as to the character of the material screened regardless of the screen standards used, and it seems particularly desirable on account of the well-known differences in the size of openings of different laboratory screens having the same nominal mesh. In making screen-sizing tests it has been customary first to consider the largest size, going progressively to the smallest, and this seems to have led to the practice of placing the smallest size .at the right-hand side of the diagram and measuring toward the left. This is not altogether convenient and might be changed to advantage, but for illustration I have preserved that feature and present the method just as I have used it for over 2 years. Direct plotting in which the intervals on the diagram are proportional to the sizes of the openings, or to the arithmetical difference between them, seems at first sight more natural and is extremely useful for certain purposes, but it makes the diagram very crowded in the smaller screen sizes while the larger ones occupy unnecessary space, making it less convenient for most purposes, and for that reason the method here discussed is the well-known one based on the ratio between openings, and is plotted in logarithms instead of the direct values of the screen opening. Metric coordinate paper is convenient, although not necessary; it is recommended, as the use of the metric scale gives a diagram of convenient size, but any scale of equal parts may be used. In order to make any screen diagram translatable in terms of any standard screen size, it is necessary to have noted on the size scale of the diagram all points corresponding to the openings of the various screens in question, instead of a single series of points as with a single screen. In drawing the diagram assume 0.001 in. (corresponding approximately to 0.025 mm.) to be the smallest size to be considered and fix this as the zero point at the lower right-hand corner of the diagram. This value is selected because the values are to be plotted in logarithms, and the logarithm of 1 is zero. Then lay off to the left for the position of each screen

Jan 1, 1918

By John Randall

IT is a fair assumption that the main purpose of any diagram is to present facts to the eye in more convenient form than they could be tabulated in figures, and this implies that a screen diagram should set forth in a convenient and familiar form certain facts as to the character of the material screened regardless. of the screen standards used, and it seems particularly desirable on account of the well-known differences in the size of openings of different laboratory screens having the same nominal mesh. In making screen-sizing tests it has been customary to first consider the largest size, going progressively to the smallest, and this seems to have led to the practice of placing the smallest size at the right-hand side of the diagram and .measuring toward the left. This is not altogether convenient and might he changed to advantage, but for illustration I have preserved that feature and present the method just as I have used it for over 2 years. Direct plotting in which the intervals on the diagram are proportional to the sizes of the openings, or to the arithmetical difference between them, seems at first sight more natural and is extremely useful for certain purposes, but it makes the diagram very crowded in the smaller screen sizes while the larger ones occupy unnecessary space, snaking it less convenient for most purposes, and for that reason the method here discussed is the well-known one based oil the ratio between openings, and is plotted in logarithms instead of the direct values of the screen opening. Metric coordinate paper is convenient, although .not necessary; it is recommended, as the use of the metric scale gives a diagram of convenient size, but any scale of equal. parts may be used. In order to make any screen diagram translatable in terms of any standard screen size, it is necessary to have rioted on the size scale of the diagram all points corresponding to the openings of the various screens in question, instead of a single series 'of points as with a single screen. In drawing the diagram assume 0.001 in. (corresponding approximately to 0.025 mm.) to be the smallest size to be considered and fix this as the zero point at the lower right-hand corner of the diagram. This value is selected because the values are to be plotted in logarithms, and the logarithm of 1 is zero. Then lay off to the left for the position of each screen

Jan 9, 1917

By Carvalho A. Felipe de

The search for environmentally friendly and cost-effective methods for gold extraction has been undertaken in order to provide alternatives to the use of cyanide leaching in the gold industry. Among such alternative reagents is the combination of chloride and hypochlorite ions due to their oxidation of metallic gold and its complexation. Therefore, the current work aims at investigating gold leaching from an oxidized material by means of a solution comprising calcium hypochlorite and sodium chlorite. The sample used in the current research contained 66.1% Fe2O3, 20.4%SiO2, and 35.7 g/t of Au. In addition, XRD and SEM-EDS analysis revealed iron oxide, quartz and muscovite as the main crystalline phases in the sample. For comparison purposes, cyanidation of the oxidized material resulted in 90% gold extraction in 24 h. The reference conditions for the leaching tests with the chlorite-hypochlorite system were: particle size −37 μm, solid/liquid ratio of 10% (w/v), 10 g/L NaCl, 10 g/L Ca (OCl)2, pH 5–6, 3 h of leaching. The effects of the: (i) Ca(OCl)2 concentration, (ii) NaCl concentration, (iii) pHrange and (iv) the effect of pulp density in the extraction of gold were assessed. In addition, the stability of the hypochlorite solutions (OCl−) was investigated. The ideal concentrations of Ca(OCl)2 and NaCl were determined as 25 g/L and 15 g/L, respectively, whereas the optimal pH range was 4–6. Under these conditions, the final gold extraction reached approximately 84%. By varying the solids content of the pulp (10%, 20% and 30%), it was observed that the lower solids value resulted in greater gold extraction (84%). The degradation of the hypochlorite solution and the possible catalytic effect of the presence of the solid were evidenced. To sumup, in the experiment, high gold extractions were achieved in shorter periods of time (3 h), as compared to the cyanidation of the same sample. On the other hand, itwas necessary to use significant amounts of the reagent due to hypochlorite instability at the pH conditions recommended for high gold extractions.

By AIME AIME

IN accordance with the provisions of Art. XII, See. 3, of the By-laws of the American Institute of Mining and Metallurgical Engineers, the Board of Directors hereby give notice of their intention to amend the By-laws as follows : Art. V, Sec. 2. Amend by substituting the word "senior" for ('first" before the words "Vice-president" in line two of the third paragraph of said section which relates to the calling of special meetings of the Board in the absence or disability of the President.

Jan 1, 1930

By Gregory J. Chekan

As part of the initial investigation and validation of a new boundary-element formulation for stress modeling in coal mines, the underground stresses and displacements at two multiple-seam coal mines with unique stress problems were modeled and predicted. The new program, LAMODEL, calculates stresses and displacements at the seam level and at requested locations in the overburden or at the surface. Both linear elastic and nonlinear seam materials can be used, and surface effects, multiple seams, and multiple mining steps can be simulated. In order to most efficiently use LAMODEL for accurate stress prediction, the program is first calibrated to the site-specific geomechanics based on previously observed stress conditions at the mine. For this calibration process, a previously mined area is "stress mapped" by quantifying the observed pillar and strata behavior using a numerical rating system. Then, the site-specific mechanical properties in the model are adjusted to provide the best correlation between the predicted stresses and the observed underground stress rating. Once calibrated, the model is then used to predict future stress problems ahead of mining. At the two case study mines, the calibrated models showed good correlation with the observed stresses and also accurately predicted upcoming high stress areas for preventive action by the mines.

Jan 5, 1999

By B Brattli

The dispersion pattern of heavy metals in soil and water is a consequence of complex geophysical and geochemical processes. Metal release from mining sites and subsequent migration occur primarily through acid mine drainage and erosion of waste and tailings dumps. Water plays a significant role in heavy metal mobilisation. Whilst it acts as a storage buffer for the pollutants, it is also the medium in which most of the reactions take place, and is undoubtedly the most significant transport vector in the pollution process. The intrinsic properties of the acidic drainage such as chemical composition, speciation of key mineral components, redox potential and pH are master variables controlling metal release, transport, deposition, reactivity and availability to biota. The mobility of heavy metals is strongly increased by acidification from acid mine drainage, and the discharge of these metals into the receiving waters results in numerous physical, chemical and biological responses in which the environment can affect the metal and vice versa. The result is an overwhelming number of association/dissociation, substitution, adsorption/desorption reactions, giving rise to a complex migration pattern. The attempt to understand and describe the dispersion pattern of heavy metals is complicated by the nature and level of interaction between the geochemical and hydrodynamic processes that generate and control the movement of the pollutants in the geosphere. Transport models which can be used to predict the behaviour of metal pollutants in a natural environment are still in the initial phases of development and their application to real life situations is limited. The Biochemical Cycle adds another dimension to the mobility of heavy metals. Metals form an important component of the food chain for man and plants. Biological uptake of metals from the bedrock and soil by organisms can result in migration paths very difficult to follow. Biodegradation or assimilation is just a tip of the iceberg.

Jan 1, 2003

By Richard E. Hucko

The U.S. Department of Energy (DOE) Coal Preparation Program focuses on providing the technical and process-development basis that can be utilized to produce environmentally acceptable clean-coal feedstocks for use as market conditions permit. A major objective of the Coal Preparation Program is the development of physical coal-cleaning technologies capable of significant removal of mineral matter and pyritic sulfur at high energy recovery levels.

Jan 1, 1989

By Keith Heasley

As part of the initial investigation and validation of a new boundary-clement formulation for stress modeling in coal mines. the underground stresses and displacements at two multiple-seam coal mines with unique stress problems are modeled and predicted. The new program, LAMODEL, calculates stresses and displacements at the seam level and at requested locations in the overburden or at the surface. Both linear elastic and non-linear seam materials can he used: and surface effects, multiple seams, and multiple mining steps can be simulated. In order to most efficiently use LAMODEL for accurate stress prediction, the program is first calibrated to the site-specific geo-mechanics based on previously observed stress conditions at the mine. For this calibration process. a previously mined area is "stress mapped" by quantifying the observed pillar and strata behavior using a numerical rating system. Then, the site-specific mechanical properties in the model are adjusted to provide the best correlation between the predicted stresses and the observed underground stress rating. Once calibrated, the model is then used to predict future stress problems abead of mining. At the two case study mines, the calibrated models showed good correlation with the observed stresses, and also accurately predicted upcoming high stress areas for preventive action by the mines.

Jan 1, 1998

By Pierre O'Dowd

"The southern Abitibi Belt is the major source of gold in Quebec. Although the northern part of the belt is quickly being developed, the area under study will not be downgraded in the near future because it still contains more than 75% of the known reserves in the belt.Gold is found in a variety of geological environments which are part of a small number of distinct structural patterns. For the exploration geologist, outlining such patterns might be easier and more productive than defining, when it is possible, the exact genetic nature of the gold mineralization.Exploring in the right place has always been one of the main concerns of explorationists. This paper briefly describes the various favourable geological settings, and outlines areas, types of structure and lithologies of high potential for gold exploration in the southern Abitibi Belt.IntroductionThe southern part of the Abitibi Belt is a profilic mining area for precious and base metals (Lulin 1990). Although mineralizing processes and controls of polymetallic deposits are well known and understood (Lydon 1984), almost every gold occurrence is a unique case and numerous models have been proposed (Roberts 1987; Hodgson and McGeehan 1982; Hodgson 1990).This study does not define new genetic models for the formation of gold deposits, neither is it meant to elaborate on the existing ones. A genetic approach, is by definition, theoretical and, to some extent, universal. It helps geologists define types of targets and exploration tools but does not outline or quantify target areas. To tentatively summarize the complexity of a genetic approach, a brief discussion on the various genetic models in vogue in Abitibi and the problems related to their use in exploration can be found at the end of this paper."

Jan 1, 1991

The population and the per capila consumption of mineral resources have both grown dramatically during the century past. It is argued that growth will continue through the century ahead but that the magnitudes of undiscovered resources are probably adequate to meet demands. The challenge that the mineral explorer of the future will face is finding deposits beneath several kilometres of barren rock.It is further argued that the principal challenge that society will face in the century ahead is the amelioration of environmental stress.

Jan 1, 1993

By E. E. Bach

STATEMENT OF THE PROBLEM THE administration of industrial organization today embraces more than the cost of production and selling prices. Competition is deeper seated than mechanical devices, overhead charges, and a shrewd manipulation of the markets. Despite the "down-to-the-minute" equipment and the "last word in organization," it is quite evident that "capacity production" will be an unknown quantity until the workman is considered as a producer, in relation to his home, as he is now considered in relation to industry. Whether or not a man shall do an honest day's work is as much a psychological condition as it is a matter of physical strength or skill. His attitude toward his work each morning is determined, to a large degree, by the environment of his home. Whether this attitude, good or bad, obtains the day through will depend entirely upon the one fact as to whether the corporation which employs him does or does not differentiate between the mechanical factor and the human factor in industry. To be more specific, sociological work, under whatever name, should be of such a character as to influence the life of a workman in such a manner as to establish a cooperative interest in his work, foster within him a spirit of contentment in his home, lead him-so to employ his leisure time that he will not lower his efficiency as a workman, destroy his domestic happiness, or endanger his standing in the community as a citizen. While no fixed rules of procedure can well be formulated for the development of the work, yet definite lines of activities will readily present themselves as applicable to the individual needs of a community. This is especially true where community influences and agencies pertaining to general welfare are easily correlated.

Jan 2, 1918

By C. E. Silverblatt, D. A. Dahlstrom

Previous bench-scale studies demonstrated that a substantial moisture reduction can be obtained by the application of steam to coal filter-cakes, particularly to those containing a limited amount of minus 200-mesh material. Consequently, U.S. Steel's Applied Research Laboratory conducted a study to determine the feasibility of steam filtration of 1/4 in. by 0 coal on a continuous pilot-scale installation in which an Eimco extractor is used. The test results showed that the moisture content of this coal could be reduced to 5.5% at a steam loading of about 175 lb of steam per ton of dry cake. In terms of steam consumption, this loading is calculated to be 1-1/2 lb of steam per lb of water removed. In some tests, only 1 lb of steam per lb of water removed was required. These levels of steam consumption are significantly less than the actual heat requirements of conventional thermal dryers. The satisfactory moisture reductions were obtained at filtration rates of 125 to 186 lb of dry solids per sq ft per hour. However, the proper design of commercial filters should improve the potential rates that can be attained. These results indicate that steam filtration has considerable economic potential for drying 1/4 in. by 0 coals and also has additional advantages over the conventional thermal drying of coal. The results of the previous bench-scale studies and those published by Burton' demonstrated that a substantial moisture-content reduction can be effected by the application of slightly superheated steam to coal filter-cakes, particularly to those containing a limited amount of minus 200-mesh material. Consequently, US Steel's Applied Research Laboratory conducted a study to determine the feasibility of steam filtration of 1/4 in. by 0 coal on a continuous basis. In the continuous process, the dewatering operation on the filter is conducted in stages. In the first, the bulk of the water in the feed slurry is removed by conventional mechanical dewatering on a portion of the filter before the steam is applied. In the second stage, steam is applied to the cake. The steam condenses and releases its latent heat, thereby reducing the viscosity of the remaining cake water; this reduced viscosity then facilitates further drainage and produces a cake of lower moisture content. Because of the availability of feed coal on a continuous basis and since steam was readily available from a low-pressure boiler, the Applied Research Laboratory selected for the test site a coal-preparation plant that cleans Pittsburgh Seam coal. A slurry of table and flotation coal in percentages as they occur normally was used as feed stock. Typical analyses of this slurry are shown in Table I. DESCRIPTION OF FILTER AND EXPERIMENTAL PROCEDURES An Eimco Extractor was selected for the evaluation of steam filtration in a continuous process. This unit was chosen because of its availability and its design features that permit relatively simple hood construction, instrumentation, and operation. A photograph of the Extractor is shown in Fig. 1. In the filter a cloth medium is used that travels horizontally and continuously with a grooved, rubber drainage belt. The total effective filter area was 12.5 sq ft. As the feed slurry flows by gravity from the feed box onto the medium,

Jan 1, 1964

By Juliana Augusto Molari, Deborah Dibbern Brunelli, Leonardo G. de Andrade e Silva, Patricia N. S. Poveda

There are several additives aimed on improving the processing characteristics as well as mechanical properties of the plastic materials. Being polypropylene is one of the main polymers used in the plastic processing industry due to its easy processability and application versatility, was chosen as the base resin for this study. Additives can aid the processing of polypropylene, either by promoting a better slip between the chains (lubricants), or by contributing to nucleation and crystallinity (nucleating). In this study, the raw materials copolymer polypropylene, lubricant (internal and external action), organic nucleating agent (metallic salt) and inorganic nucleating agent (metallic oxide) were considered. Mechanical tensile tests, Charpy impact and spiral flow to verify melt index were performed to characterize the samples with additives and standard (copolymer polypropylene). The interference of these additives with polymeric matrix was observed.

Mar 1, 2018

By Thomas L. McVay

The Bureau of Mines made laboratory batch and small-scale continuous flotation tests of a sample of pegmatite rock from a deposit of the Lithium Corporation of America, Inc., near Kings Mountain, N.C., to determine the feasibility of producing commercial-grade spodumene concentrates. Various reagents and flotation procedures were tested to determine the optimum conditions for floating the spodumene and retarding the gangue minerals. The best results were obtained when sodium fluoride and lignin sulfonate were used as the pulp conditioner and oleic acid was used as the spodumene collector. The continuous flotation tests indicated that commercial-grade. spodumene concentrates analyzing 6.4 pct. Li2O could be produced with recovery of 77 pct. of the lithia in the ore.

Jan 1, 1962

By J. B. Campbell, V. V. Valleroy, B. T. Willman, L. W. Powers

A steam drive of heavy oil was field tested in a shallow, low oil-saturation formation near Deerfield, Mo. The pilot was conducted in the Warner formation, a sandstone containing an 18' API oil having 1,000-cp viscosity at the 60F origind reservoir temperature. The formation war at a depth of 160 ft. Steam was injected into nine input wells arranged in an array of inverted five-spot patterns. In the completely confined center pattern, 14 temperature observation wells were installed to obtain thermal data and observe test progress. Late in the test, slugs of ammonia were injected to trace the flow paths of injected fluids. From the test area about 7,000 bbl of oil were produced. Data were obtained on areal and vertical temperature distribution, steam front advance, reservoir fluid movement and terminal saturations. This field test of a steam drive (I) demonstrated the feasibility of the method, (2) confirmed that the low residual oil saturations observed in the laboratory are obtained in the steam-swept region in the field and (3) provided recovery and conformance data for one set of field conditions. INTRODUCTION The Deerfield steam drive pilot test was conducted in a shallow sandstone containing 1,000-cp oil. The venture was undertaken cooperatively by the research and production departments of Carter Oil Co., which organizations have since been consolidated into Esso Production Research Co. and Humble Oil & Refining Co.. respectively. The production department was interested in steam injection at Deerfield because it appeared to be the most promising method of commercially producing this heavy oil deposit. The research department was interested in applying the new recovery method and in evaluating its performance in the field. At the time the test was begun, the initial oil saturation was not well known. Subsequent air coring and early pilot results confirmed that there was too little oil in place for profitable commercial exploitation by steam. Pilot termination at that time, however, would have been premature for evaluating field performance of the process, and the tert was continued to obtain additional data on steam injection as a recovery method. The test was located in Vernon County, Mo., about 10 miles north of the town of Deerfield and only a few miles from the Kansas border. The pilot site was selected as typical of the area. The location represented neither the highest nor the lowest oil saturation region in the acreage under lease in 1954. The steam drive was conducted in the Warner sandstone of Lower Pennsylvanian age. At the test site the top of the Warner occurs at about 160 ft subsurface and the formation is a fine- to medium-grained micaceous sandstone that dips gently to the northwest at the rate of 12 to 15 ft/ mile. A cross-section and permeability profile of the test location are shown in Fig. 1. At the pilot location the average total thickness of the Warner formation is about 43 ft, but the effective thickness for steam drive is 26 ft. Two distinct types of hydrocarbon saturation are apparent. The lower portion of the total sand, averaging about 17 ft thick, contains a very heavy asphaltic material that will not flow under the influence of a steam drive. This bottom interval, referred to as a dead oil residue, was not considered as part of the net sand undergoing steam exploitation. The initial formation and fluid properties of the upper 26 ft in the test area are summarized in Table 1, and variation of oil viscosity with temperature is shown in Fig. 2. Imbibition tests on preserved core samples taken at the end of the pilot test showed that the Warner sandstone was then neutral or slightly water-wet. Initially, the reservoir may have been strongly water-wet as indicated by low relative permeability to water during both water injection testing and early steam injection. PRIOR HISTORY Initial production tests of wells at the pilot site produced water with only a faint show of oil. No gas was produced except at Well 7-W in the pilot area and at another well about 1/3 mile northeast of the pilot. Prior to the start of the steam drive, a two-well water injection test and a two-well air injection test were conducted. No oil was produced by either. Water was pumped into Well I-W in the northeast corner of the pilot area with simultaneous production from Well 1 (Fig. 3). The air-injection tat was run at input Well 9-W and its offset, Well 2, in the southwest corner. Air and water injectivities were about the same when corrected for viscosity and pressure differences.

By Meguru Nagamori

DURING the smelting of the sulfide ores of copper, nickel, and certain other metals, a matte phase is formed. For a better understanding of the physico-chemical properties of mattes, binary systems such as Cu-S, Ni-S, Fe-S, and so forth, should be studied, especially in the vicinity of liquid compounds such as Cu2S, Ni3S2, FeS, and so forth. These compounds are relatively stable in the solid state although they can exhibit appreciable deviations from stoichiometry. With small deviations from stoichiometry there are large changes in the activity of both sulfur and metal this is a characteristic of both solid and liquid sul-fides near the stoichiometric compositions. In the vicinityof molten Cu2S,1 for instance, the activity of sulfur increases about 100 times for a 0.012 increase in the mole fraction of sulfur and, correspondingly, the activity of copper decreases greatly. In this sens the minor deviations from stoichiometry should be carefully taken into account in studies of such metal-sulfur melts. Metal-sulfur melts may be considered to have properties intermediate between metallic solutions and molten salts, i.e., neither entirely metallic nor entirely ionic. The radius of the ion sZ- is 1.84 as compared with 1.04? for a single bond covalent s.2 It is therefore inferred that when the sulfur is more ionic its partial molar volume is larger, although metal-metal, metal-sulfur, and sulfur-sulfur interactions may bring about further complexities. Thus, it is to be expected that the molar volumes, which are derived from density-composition relations, will help in resolving the structure of the melts. In this study the maximum bubble pressure method with bubbling gases of H2, H2S, and Ar, .was employed to measure the density. EXPERIMENTAL Materials. Silver of 99.95 pct purity was melted in an alumina crucible and hydrogen gas was then bubbled through the liquid for the deoxidation. In preparation of Cu2S, electrolytic copper powder (>99.9 pct Cu) was mixed with precipitated sulfur and heated to 1200°C in an alumina crucible under a hydrogen atmosphere. Mixtures having the approximate compositions FeS and Ni3S2 were prepared by heating reagent grade electrolytic iron or reduced nickel powder with precipitated sulfur under a hydrogen atmosphere. The H2S gas was of 98.5 pct purity, the impurities being mostly CO2 and CS2 which hardly contaminate the melts. Apparatus. The crucible system is shown schematically in Fig. 1. To minimize the variation of melt composition during a density measurement, the apparatus was designed in such a way that either Ar, H2, H2S, or mixtures of these gases could be used as the bubbling gas. When the melt had a high partial pressure of sulfur, H2S gas was used. When the partial pressure of sulfur was so low that oxygen might dissolve in the melt, the use of H2 was preferred. In intermediate cases, argon or mixtures of H2-H2S were used. Density of Dibutylphtalate. Dibutylphtalate was used as the manometer fluid. Relative to distilled water, the density of the dibutylphtalate, pdib g per cc, was measured and found to be: pdib (25°C) = 1.046 i 0.002. With the use of the temperature coefficient reported by Kemppinen and Gokcen,3 the following value was

Jan 1, 1970

By A. Valenzuel

Arsenic is a common impurity in copper sulfide concentrates treated pyrometallurgically, which inevitably during the smelting-converting process reports in the final copper product affecting its properties, but also it is a very toxic occupational hazard. Arsenic recovery or disposal from concentrates or arsenic-containing copper smelter dusts have been practiced in the metallurgical industry for many years. It has been recovered principally as arsenic trioxide by roasting or leaching then precipitated. On the other hand, several hydrometallurgical processes have been developed and implemented in smelters to remove it from arsenicbearing dusts and stabilize it prior to disposal in the form of a solid compound, either as calcium arsenate, arsenic sulfide or ferric arsenate. This paper reviews the methods implemented for arsenic recovery worldwide and arsenic disposal in the metallurgical industry.

May 1, 2001

By T. L. Joseph

The purpose of this article is to describe briefly the operation of a 6-ton blast furnace on a charge of bauxite, limestone, iron ore, and cast-iron turnings and to point out the bearing which smelting such a charge has upon the production of alumina cement. One object of the experiment, conducted by the Bureau of Mines in cooperation with the Aluminum Co. of America, was to determine whether tae so-called Pedersen process3 can be applied to the blast furnace. This process consists of smelting a charge of bauxite, iron ore, and. limestone, and results in to products. One is a slag containing about 50 per cent of A1203 and is intended for use in manufacturing aluminum, and the other is iron low in sulphur. Complete details of the test are published in other reports4. Blast-furnace slag is now recognized as a satisfactory and economical raw material for making Portland cement, Wm. A. Forbes5 has recently reported that in 1926 an important steel interest used well over 1 million tons of slag in producing about 24 million long, tons of cement. This is equivalent to about ½ ton of slag for each ton of cement. Alumina cement can be made direct in the blast furnace. Its physical character would have to be changed by grinding, but no change in its chemical composition would be necessary.

Jan 1, 1928