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By Ikuhiro Sumi

A new steelmaking process, in which manganese ore was intentionally reduced, was developed to achieve a higher manganese Yield using a combined blowing converter. In this study, manganese behavior was discussed through the introduction of a model. Apparent reduction rates of manganese were calculated by the two terms that were determined experimentally, with SOkg and 2S0ton combined blowing converters. The model calculated manganese changes during the operation. We applied the model to the actual operation and found that manganese behavior was predicted fairly well by this model.

Jan 1, 1996

By Arthur G. Hunt

Smelting using the direct-to-blister process commenced at Olympic Dam on 31 July 1988. The unique nature of the Olympic Dam ore body led to the selection of the direct to blister smelting process. Significant improvement in the design of the furnace and the understanding of the fundamentals of the process and its operation has occurred in the 10 years of operation. The paper will discuss the operation of the #1 Smelter and the design, preparation for start up and early operating experience of the #2 Smelter.

Jan 1, 1999

By W. F. Miao

Nanocrystalline mixtures of Nd2Fe14B and a-Fe have been synthesized by mechanical milling and heat treatment. The samples exhibit isotropic behavior, with significant remanence enhancement associated with exchange coupling across the interfaces of hard and soft magnetic phases. Measurements of the effect of heat treatment on structure and magnetic behavior demonstrate the important influence of grain size on magnetic properties. The effect of alloy additions to increase the saturation magnetization of the soft phase and the magnetocrystalline anisotropy of the hard phase has also been investigated.

Jan 1, 1997

By H. Kandemir

An experimental study of the bacterial oxidation of naturally occurring high-purity sulphide minerals (FeS2, Fe1-xS, Cu5FeS4, ZnS) is presented using a mesophilic strain of T. ferrooxidans. As well as metal analyses and solution pH, partitioning of sulphide sulphur into elemental sulphur and sulphate has been monitored as a function of leach time. Partially oxidized sulphide substrates have been characterized, at regular time intervals, by X-ray diffraction methods and extracellular organic compounds reporting into leach solution .have been identified by thin layer -chromatography.

Jan 1, 1985

By L. Cifuentes

Electrodialysis (ED), i.e. a technique based on the effects of electrically charged membranes on ions in solution in an electric field, has been applied to Cu-Fe-As-Sb- H2SO4 electrolytes similar to those used in copper electrorefining and electrowinning operations. The effects of current density, time and species concentration have been studied in a batch ED cell. The technique has shown to be effective in concentrating and separating a range of ions and points to possible new methods of treating copper electrometallurgy effluents.

Jan 1, 1999

By Jr. Loper, M. H. Kim, H. H. Jo, C. S. Kang, T. S. Song

"An investigation has been conducted to describe the effect of grain refiner (e.g.,Ti) or modifier (e.g., Sr) on the microstructure of an Al-11.3wt%Si alloy produced by the Ohno horizontal continuous casting process using a heated mold so as to obtain directional solidification at high cooling rate of 300 to 2000°C/s. Experimental results demonstrated that the directionality of the primary a grain was promoted by the addition of0.2 to 0.4%Ti or by the addition of0.02%Sr, whereas the addition of0.6%Ti suppressed this directionality. Feathery a grains were promoted by the addition of 0.2%Ti, while these feathery a grains were suppressed when over 0.4%Ti (grain refinement) or when 0.02%Sr was added. The addition of Ti also resulted in increased coarsening of the eutectic Si in these Al-1 l.3wt%Si alloys.IntroductionThe mechanical properties of conventionally cast Al-Si alloys can be enhanced through judicious control of the casting parameters, by the addition of grain refiners (e.g., Ti) and by the addition of eutectic modifiers (e.g., Sr).[1-3] The Ohno continuous casting process[4-5] uses a heated mold (maintained at a temperature above the alloy liquidus temperature) to produce a casting with a mirror surface free of shrinkage defects. The process is especially suitable for the production of high quality and non-deformable rods of small diameter. This study was conducted at investigate the effects of Ti and Sr on the microstructure of Al-1 l .3wt%Si rods cast by the 01).no process."

Jan 1, 1998

By Chikabumi Yamauchi, Mitsuru Tanahashi, Jutaro Miura, Takaharu Iwadachi, Toshiharu Fujisawa

"Tue oxidation behavior of molten Cu-Be alloys was investigated by exposing· the molten Cu-Be alloys to various Ar-O2 atmospheres to control the oxygen partial pressure, PO2 = 10 ~105 Pa at 1423 K. The following results were obtained:• The oxygen · partial pressure in gas phase affects the morphology of the oxide formed on the surface of the alloy and · the oxidation rate of beryllium.• At lower oxygen partial pressure, a molten Cu-Be alloy is covered with a homogeneous and compact internal layer of BeO. Thus, the beryllium oxidation rate can be minimized.• By adding a small amount of calcium or zirconium into the molten Cu-0.5 mass% Be alloy, a protective BeO layer is formed even at higher oxygen partial pressure. Thus, the beryllium oxidation rate can be reduced.IntroductionCopper-beryllium (Cu-Be) alloys are well recognized for their unique properties, such as high electrical conductivity, high strength, high fatigue strength, excellent properties at elevated temperatures, good formability and good corrosion resistance. .This extraordinary collection of properties are the reasons why Cu-Be alloys are expected to be ""Key-materials"", which are necessary to further advance science and technology and to be applied in.various fields such as electronic devices, machine parts, repeater housings of undersea optical fiber communication cables, etc.However, a large amount of beryllium is oxidized to BeO in melting stage of the current Cu-Be alloy production process, because beryllium is a highly reactive element. This is one of the ·main factors that negatively affect the production yield and th_e product quality."

Jan 1, 2000

By Phillip B. Messersmith, Emmanuel P. Giannelis

"A versatile in-situ polymerization approach is described for the synthesis of polymerceramic nanocomposites consisting of two-dimensional layers of mica-type silicate (MTS) within polymer matrices. Functionalized, organically modified mica-type silicates (OMTS) were used to promote delamination/dispersion of the host layers and initiate polymerization of organic rrionomer. Epoxy nanocomposites prepared in this manner exhibit substantial modulus reinforcement at low silicate loadings. The water vapor permeability of the poly(?-caprolactone) nanocomposite containing 4.8% silicate by volume was reduced by nearly an order of magnitude compared to pure poly (?-caprolactone).IntroductionPolymer matrix nanocomposites are a relatively new class of materials with dimensions typically in the range of 1-100 nm.1 In general, because of the ultrafine phase dimensions involved, nanocomposites exhibit new and improved properties when compared to their micro- or macrocomposite counterparts. We as well as others are currently investigating the design, synthesis and characterization of polymer-ceramic nanocomposites. Our effort, in particular, has focused on the use of mica-type silicates (MTS) with various thermoplastic and thermosetting matrices.2-5MTS's belong to the general family of 2: 1 layered silicates. Their crystal structure consists of layers of two silica tetrahedral sheets fused to an edge-shared octahedral sheet of either aluminum or magnesium hydroxide. Stacking of the layers leads to a regular van der Waals gap or interlayer.6 Isomorphic substitution within the layers generates negative charges that are counterbalanced by cations residing in the interlayers. Although the natural forms of MTS's usually contain hydrated Na+ or K+ ions, ion exchange reactions with organic cations (e.g. alkylammonium ions) can render the normally hydrophilic MTS's organophilic."

Jan 1, 1994

By Ch. -A. Gandin, M. Rappaz

"The grain selection mechanism which occurs during the growth of columnar dendritic structures is routinely used in the investment casting industry to produce directionally solidified (DS) and single crystal turbine blades. However, the evolution of the grain density with increasing distance from the chill has rarely been correlated with the evolution of the grain texture. This contribution presents a three-dimensional (3-D) stochastic modeling approach which permits the computation of grain maps, pole figures and grain density evolutions in DS superalloys. These predictions are compared with measurements resulting from an automatic indexing technique of Electron Back-Scattered diffraction Patterns. This 3-D stochastic model, which applies to uniform temperature situations, has to be extended to the dendritic growth in a thermal gradient. As a preliminary step, a 2-D Cellular Automaton (CA) has been coupled recently to Finite Element (FE) heat flow computations in order to predict the grain structures in complex shape investment cast part. The application of this CAFE model to the investment casting of a turbine blade is presented. Considering these results, the extension of the CAFE algorithm to three dimensions is discussed.INTRODUCTIONThe selection of columnar grains during the directional solidification of alloys plays a key role during the investment casting of directionally solidified (DS) and single crystal (SC) components for aerospace applications [I]. This selection mechanism, leading to a competition of the dendritic network propagation at grain boundaries, has been the subject of many investigations. In particular, the study of Walton and Chalmers [2] is remarkable since it provides a link between the evolutions of the density and of the texture of columnar grains with increasing distance from the mold wall. Since this original work of Walton and Chalmers, two new tools have become available, which enable one to revisit the problem of grain selection in much greater depth. The first one is a fully automatic indexing technique of Electron Back-Scattered diffraction Patterns (EBSPs) [3-6] which directly gives the crystallographic orientation of the solid at any location of the specimen. Pole figures, orientation distributions, misorientations between grains can be visualized very easily with this technique. This information can be directly compared with the results of a second tool: a three-dimensional (3-D) stochastic model (SM) describing the nucleation and growth of grains in a uniform temperature field [6-9]. In order to extend this model to non-uniform temperature situations, a preliminary 2-D model has been developed [10]. It is based on a Cellular Automaton (CA) algorithm coupled with Finite Element (FE) heat flow computations. Since the details of both the automatic indexing technique of EBSPs and the simulation tools have already been published [3-10], only a brief summary is given here."

Jan 1, 1994

By Tsembel Darjaa, Toru H. Okabe, Yoshiaki Umetsu

"With the purpose of extracting molybdenum and rhenium from molybdenum sulfide concentrate; .electrolysis of slurry, solvent extraction and ·precipitation operations were carried out. The slurry of the concentrate in 10 mass% NaCl aqueous solution was continuously circulated into a vertical type 10 stack bipolar electrolytic cell consisted of carbon electrode disks, and, the concentrate was dissolved by electrochemically generated oxidizers at 313 K. The current efficiency for molybdenum dissolution was 73 % after 10 hours electrolysis, and the leach solution was found to contain 0.2 mol/l of molybdenum and 4x10-5 mol/l rhenium. This result shows the dissolution is more than 8 times faster than that obtained using a single cell. The leach solution from electro-oxidation was then subjected to a solvent extraction for rhenium which is then recovered as sulfides. After rhenium separation, molybdenum was precipitated by pH adjustment, and solid MoO3 (H2O)x crystals, free of sulfate, were obtained from the leach solution containing large amount of so42-.IntroductionIn the past, electro-oxidation using a bipolar cell was applied for leaching molybdenite concentrate and ores at U. S. Bureau of Mines [1-3] and also at Bhabha Atomic Research Center [4]. In· these previous studies, Moebious type bipolar cells, in which electrode plates were vertically inserted into the free surface of the electrolyte, were employed and its effectiveness was demonstrated.Recently, the present authors studied on leaching of Mongolian molybdenite concentrate, and the effectiveness of leaching of the concentrate by electro-oxidation in alkaline and acidic NaCl solutions was demonstrated [5]. The leaching reaction during the process can be explained by the 18 electron transfer reaction of molybdenite (MoS2) with the oxidizers produced in-situ by electrolysis of NaCl aqueous solution. Further investigation was made with respect to various process parameters for electrooxidation such as pH, pulp density and temperature of the slurry, and the dissolution behavior of minor elements such as iron, copper, and rhenium [6]. Solubilities of molybdenum in the leach solution at, various temperatures and pH .was · studied, and feasibility of molybdenum recovery by hydrolysis of molybdenum species was demonstrated. By adjusting the pH of the leach solution, molybdenum oxides or hydroxides free from sulfate were successfully obtained from the solution containing large amount of sulfate ion. Rhenium present in the concentrate at a level of several tens of mass ppm was found to dissolve into the leach solution, and co-precipitate with the molybdenum compounds. Rhenium in the leach solutions, therefore, has to be recovered before precipitation of molybdenum, otherwise it is lost in the precipitate."

Jan 1, 2000

By Georgette Smits

The gun-sprayed refractory lining of electrothermal furnaces used for the manufacture of carbon disulphide from liquid sulphur and charcoal at between 800 and l000°C are severely attacked during the process. A mineralogical study of samples of eroded refractory material disclosed that carbon disulphide had penetrated the lining, causing the precipitation of sulphides and carbon, and the decomposition of mullite, a major constituent of the lining, to corundum and amorphous silica. Calcium, iron, titanium, and chromium are undesirable cations in a refractory that is used in furnaces for the production of carbon disulphide, since they react readily with this substance. A series of tests, in which samples were exposed to different amounts of carbon disulphide for various residence times and at different temperatures, was carried out with eight types of aluminosilicate-based castable and brick refractory materials, to compare their resistance to attack by carbon disulphide. Mineralogical investigation of the test cores showed that castable refractory materials are unsuitable for this type of process because of the presence of calcium aluminates and other impurities in the cement. Of all the refractories that were tested, a mullite brick of low porosity, containing a minimum amount of impurities, appeared to be the most suitable for use in this type of operation.

Jan 1, 1989

The copper concentrate market is becoming increasingly unstable. In the early 1990s large concentrate stocks were built up and the glut was cleared only after treatment charges rose so sharply that 'non-traditional' custom smelter capacity, such as in Kazakhstan, could be employed, By 1994 the market had shifted and Western smelters were unable to secure enough concentrates to operate full out. The reason for these sharp swings in the market balance is that virtllally all the recent mine development has been non-integrated. With different companies developing new mine . and smelter capacity, it is inevitable that the pace of expansion in the two sectors will not be coordinated. For many years the Japanese smelters were the major buyers from the new mm-integrated mines. However, Japanese smelter capacity is unlikely to increase appreciably in the future and this stabilizing influence will be very difficult to replace. This paper will examine the likely concentrate/smelter balance over the next five years and will forecast the likely direction of? treatment charges. It will also touch on the critical variables in assessing the viability of new greenfield custom smelter capacity, such as proximity to concentrate sources, by-product sulfuric acid prices and, most importantly, tariff protection.

Jan 1, 1995

By Art Johnston

Gas handling at Magma Copper Company's, San Manuel smelter receives process gas from a flash smelting furnace and four copper converters. The major gas handling equipment consists of four electrostatic precipitators and a sulfuric acid plant. Process vessels in gas handling are typically confined spaces. Lethal gases., mechanical and chemical hazards, and the difficulty of rescue, should an accident occur, makes this area a must in the safety plan. The presence of hazardous chemicals and explosive gases in process vessels and piping are of major concern when repairs are required. Proper job procedures are critical to prevent injury during repairs. This includes plant employees and contractors who are likely to be unfamiliar with the hazards involved. The safe operation of a gas handling operation must include the functions of operations employees on a daily basis. This includes a safe working environment and involvement. of all employees in the safety program. If an injury does occur quick medical response is critical to prevent serious injury. Medical responders must be adeqliately trained and prepared to treat the injured person without becoming victims themselves.. The methods used at Magma copper Company to deal with these safety problems are the focus of this presentation.

Jan 1, 1992

Silver has the highest electrical conductivity of all metals and consequently this property is an attractive feature which makes it a leading candidate for use in electronic devices. The research conducted was focused primarily on the development of a process for obtaining a deposited silver-coating onto alumina, for applications related to electrical-conducting devices and, ancillarily, catalysts. Alumina balls and plane substrates were utilized for the investigation. The coating process employed an aqueous arnmoniacal silver-nitrate electrolytes with a formaldehyde solution as the reductant. Modifying additives - an activator which would be expected to promote good deposition-characteristics onto the (dielectric) substrate and an inhibitor which would obviate homogeneous reduction (precipitation) of silver was observed when the activator-containing silver-electrolyte reductant constituents were combined. However, the silver-electrolyte/reductant system with inhibitor could be employed (at 80°C) to achieve a viable (subject to future research optimization) coating on alumina. The influence of the processing temperature on the deposition process was delineated during the course of the research. The morphology of the deposited-silver on the alumina balls was assessed by SEM imaging. A tape-peel test was employed, with the plane substrates, to semi-quantitatively characterize the adhesion to the alumina.

Jan 1, 1998

By Art Johnston

Gas handling at Magma Copper company's, San Manuel smelter receives process gas from a flash .smelting furnace and four copper converters. The major gas handling equip11lent consists of four electrostatic precipitators and a sulfuric acid plant. Process ,vessels in gas handling are, typically confined, spaces. Lethal gases, mechanical and chemical hazards, and the difficulty of rescue, should an accident occur, makes this area a must in the safety plan. The presence': of hazardous chemicals and explosive gases in process' vessels and piping are of major concern when repairs' are required. Proper job procedures are critical to prevent injury during repairs. This includes plant employees and contractors who are likely to be unfamiliar with the hazards ,involved. The safe operation of a gas handling operation must include the functions of operations employees on a daily basis. This includes a safe working environment and involvement of all employees in the safety program. If an injury does occur quick medical response is critical to prevent serious injury. Medical responders must be adequately trained and prepared to treat the injured person without becoming victims' themselves. The methods used at Magma Copper Company to deal with these safety problems are the focus of this presentation.

Jan 1, 1992

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from the University of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

By M. I. Zinigrad

A model of an ideal associated solution is presented. This model takes into account the existence of complexes of various compositions, sizes and geometries and allows calculating thermodynamic properties and phase diagrams of binary alloys. The model has been used formerly to calculate thermodynamic parameters and the position of the liquidus line for binary eutectic systems and also those having a stable compound in the solid phase. In all the cases the model parameters were not adjusted rather estimated from melting temperatures of the components. The recent studies dealt with the influence of arbitrary-stoichiometry associates on the equilibrium thermodynamic properties of liquid alloys. The application of the model to eutectic systems and systems having an unlimited solubility in solid and liquid states close to liquidus has been considered. It was shown that if the difference in melting temperatures of the components was small, different types of fusibility diagrams were possible: eutectic diagrams, cigar-shaped diagrams or diagrams with upper or lower azeotropic points. Peritectic transformations could take place when the difference in melting temperatures of the components was large. The present work is devoted to calculation of phase diagrams and thermodynamic properties of binary systems on the basis of chrome.

Jan 1, 2006

By Yuzhe Zhang, Xiaodi Huang, Xinli Wang, Bowen Li, Matthew Andriese, Jiann-Yang Hwang, Zhiwei Peng

The recycling of waste tires has been a big environmental problem. About 280 million waste tires are produced annually in the United States and more than 2 billion tires are stockpiled, which cause fire hazards and health issues. Tire rubbers are insoluble elastic high polymer materials. They are not biodegradable and may take hundreds of years to decompose in the natural environment. Microwave irradiation can be a thermal processing method for the decomposition of tire rubbers. In this study, the microwave absorption properties of waste tire at various temperatures are characterized to determine the conditions favorable for the microwave heating of waste tires.

Jan 1, 2015