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By J. R. Hartin

Traditionally, many of the advances in casting technology have been made by expensive and time consuming trial-and-error methodology. Modeling of the complex solidification process promises production of castings which are made "right the first time." Even though several models are available for simulation of conventional casting processes, none of them address this relatively new technology of investment cast titanium aluminides. In this paper, modification and application of a transient, three-dimensional, fully coupled fluid flow and heat transfer solidification modeling computer program to the analysis of centrifugally cast titanium aluminides is discussed. The predictive results of the program are compared to qualities of actual cast parts for validation.

Jan 1, 1992

Rapidly solidified TiAl-Cr-xNb-Y(x=2,4,6, at.%) alloys have been produced using a single roller melt spinning method. The microstructure of alloy ribbon was refined and component became more homogeneously by rapid solidification technology. There were two phases in alloy ribbons, including -TiAl and 2-Ti3Al phases, yet the amount of 2-Ti3Al phase in matrix obviously increased by rapid solidification than cast alloys. The micro-hardness testing also carried out. Compared to the cast alloys, the alloy ribbons have much higher hardness.

Jan 1, 2009

By Gerardo Muñoz

All along this century CODELCO's smelters have been operating on conventional technology, which Codelco has streamlined by using oxygen, developing oxy-fuel burners for reverberatory furnaces and introducing oxygen smelting of concentrates in converters (Teniente Converters). Chuquicamata began capturing sulfur from its first Teniente Converter in 1985. Since then, it has implemented a program allowing to gradually increase such capture. In 1994 a Frame Law on the Environment was enacted in Chile. By virtue thereof and of CODELCO's corporate environmental policy, an investment program aimed at capturing more than 95% of gaseous pollutants in all its smelters in a term not exceeding twelve years was established. The above entails a substantial improvement of the operational management as regards fugitive gases capture and treatment. This paper describes the way CODELCO is to deal with this challenge with a view to fully complying with environmental regulations and obtaining the required environmental certifications of its operations.

Jan 1, 1996

By Martín Reyes

Iron concentration by ion flotation techniques, from sulfate solutions in presence of zinc was studied in a laboratory flotation column by continuous mode using a synthesized sand shell plate sparger, an anionic collector, promoters, and surfactant propylenglicol 400. Effects of experimental parameters, such as the concentration of reagent: potassium amyl xanthate and dithiophosphate, superficial gas velocity, and superficial liquid velocity were studied in terms of the recovery and enrichment of Fe (III). The results show that the iron elimination from the solution in the presence and absence of zinc (II) are of 59 % and 72 % respectively. The flotation efficiencies decrease with an increase of the concentration of xanthate and air flow rate. The best recovery was achieved, at Jg 0.1 cm/s, Jl 0.72 cm/s and a mixture of xanthate and dithiophosphate as promoter. It was also demonstrated that it is possible to selectively separate and concentrate iron (III) from solutions containing zinc. The behavior of iron ion flotation in a flotation column is reported in this research as a gas hold up, superficial gas velocity, bubble size and superficial bubbles area flux function. The results show that the extraction of aqueous ions of metal iron by ion flotation is strongly affected by: [C], Jg (cm/s), eg (%), Db (mm), Jl (cm/s), y Sb (s-1).

Jan 1, 2009

By C. Allen, A. Roy, J. W. Evans

A spouted bed electrode (SBE) has been used, in laboratory experiments, to electrowin zinc from zinc chloride electrolytes with the objective of determining the suitability of this electrode for commercial application. Zinc was successfully electrowon at current densities ranging up to 4,38 lA/m2, which are an order of magnitude larger than those used at present in the zinc industry. Current efficiencies, for the cell with the SBE, have been as high as 90% and DC energy consumption as low as 2.8 kWh/kg zinc deposited. The performance of the cell has been measured as a function of current density, anode type, cell diaphragm, addition of tributyl ammonium chloride and purging of the electrolyte (to remove dissolved chlorine).

Jan 1, 2000

By Chidchai Loyprasert, R. A. Stoehr

"A computer model has been developed to predict grain structures in alloys solidified under unidirectional flow using a combination of three techniques -- solution of the equations for flow of an incompressible fluid bounded by curved surfaces by the SOLA-SURF algorithm, calculation of heat flow by a finite difference method, and simulation of grain formation by a two-dimensional cellular automaton (CA) model. The changing rigid surface has been taken into account. Heterogeneous and homogeneous nucleation are considered, and the growth kinetics of a dendrite tip are evaluated by the Kurz-Giovanola-Trivedi (KGT) model. These calculations were applied to solidification of an Al-4.5% Cu alloy flowing over a chill on the bottom of a channel, a system for which experimental results were available. Using a variety of flow rates and superheats, agreement between the computed and experimental results were very good including transitions between columnar and equiaxed grains, the aspect ratio of the grains, and the inclination of the grains to the flow.IntroductionModeling of casting and solidification processes has developed over the years along two distinct tracks: (1.) modeling of macroscopic heat transfer and fluid flow for design purposes, and (2.) modeling of microscopic processes such as nucleation and growth in order to improve the scientific understanding of the phenomena involved. The present work is an attempt to combine the macroscopic and microscopic approaches for the solidification of an alloy flowing over a chill. The specific case chosen is that of an aluminum-4.5 % copper alloy flowing linearly over a water-cooled copper chill for which experimental results were available over a range of flow rates and superheats. For the macroscopic calculations, the SOLA-SURF algorithm for solution of the twodimensional fluid flow equations was combined with the finite difference method (FDM) for calculating heat transfer. For the microscopic calculations, heterogeneous and homogeneous nucleation were considered, and the growth kinetics at the dendrite tips were evaluated. The cellular automaton (CA) technique was used to apply the microscopic kinetics to the temperature and .flow conditions."

Jan 1, 1999

By Marco Olper

The CX-EW technology, developed by B.U.S Engitec, is improved introducing besides the battery paste electrowinning, the direct electrorefining of metallic lead (grids and poles) obtained from CX breakers. This new concept of electrorefming the antimonial lead scrap is aimed to the production of 99.99 lead and of slimes with high antimony content, avoiding gaseous emissions in melting lead scrap, and expensive and pollutant thermic refining operations. In this way, practically all lead content in the battery is available as 99.99 lead, hence with a wider market for the lead recyclers. This paper will describe the tests performed on a pilot plant scale with special reference to the relatively low energy consumption of the process.

Jan 1, 1993

By V. M. Mukhin

Among the methods proposed for spent activated carbon regeneration, the most acceptable is, thermal reactivation, because in this case the existing equipment for manufacture of activated carbon can be adapted for this purpose. In order to conduct the process of thermal re-activation of spent activated carbon directly at gold mills, a full-scale drum-type furnace with external electric heating has been developed, i.e. EPV-300 model with a throughput rate of 50 to 120 kg/hour. Its use ensures restoration of the adsorption properties of carbon up to the level of fresh activated carbon with an insignificant (by 0.7%) decrease in strength and with a high (95% to 97%) yield of reactivated carbon. During the recent years, activated powder carbon has been extensively used in flotation processes for treating polymetallic ores at ore treating plants to improve recoveries of main metals (copper, lead, nickel, etc.). Especially large volumes of activated powder carbon are used at the Talnakh concentrator of the Norilsk Mining and Metallurgical Complex in Russia for absorption of residual flotation reagents from recycled water in order to ensure efficient selective separation of minerals with similar physical and chemical properties.

Jan 1, 2006

By Katsutoshi Komeya

Aluminum nitride(A1N) is a theoretically high thermal conductive ceramic, but is a poor sinterable one because of its covalent bond structure. The densification of A1N had to be done first. It was found in 1968 that rare earth compounds as yttria were an excellent sintering aids. Recently more improvement of conductivity was attained by following effects of yttria: (1) trapping of oxygen in A1N sources to form yttrium aluminates, (2)elimination of the aluminates by heating in carbo-reductive atmosphere. Consequently very high thermal conductivity of up to 270W/mK has been developed. Thus A1N applications for substrates and packages have been opened.

Jan 1, 1992

By M. Furuta

Tamano Smelter of Hibi Kyodo Smelting Co., Ltd. has been operating without a slag cleaning furnace (SCF) since its start-up in 1972. It has used its own developed coke combustion technology, the Tamano-Type Flash Smelting Furnace (T-FSF). The coke combustion technology that is the core of the process, along with the installation of a computer guided system and the improvement of the concentrate burner combustion in the T-FSF have all contributed to having acceptable copper loss levels in the slag without using a SCF. However, recently, because a high concentrate charge rate has been used in order to achieve a high matte grade in the T-FSF, a short settling time has been experienced and copper losses in the slag have become difficult to maintain at a lower level. Furthermore it is estimated that copper losses will further increase after the completion of the next expansion because with the aim of having a higher matte grade operation at 67% less coke will be charged and the reduction effect of the settler will be smaller. Therefore, in order to maintain the copper losses in the slag within proper levels the installation of SCF was decided. This paper, describes the operation before the introduction of SCF along with some theoretical considerations of slag chemistry.

Jan 1, 2006

By Tobias Pröll, Bernhard Kronberger, Joachim Rohovec, Werner Hölt, Hermann Hofbauer

"As this is only a first draft, more precise explanations as well as detailed schemes, figures and plots will be included in the final draft. The description og the 100 kW test rig will also be mor detailed as construction is ongoing and will be finished during the summer. Furthermore simulations are to be finished shortly; so details on combustibles and gas concentrations will also be included in the final draft.AbstractOxyFuel combustion is a key technology for the efficient separation of CO2 from fuel combus¬tion (especially coal). Since coal plays a minor role in the Austrian energy mix the application of OxyFuel towards other fuels (biomass, waste fuels) is interesting to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alter¬native fuels is also interesting from a strategic point of view in order to generate knowledge for operation of capture ready cofiring and waste/sludge-incineration plants. OxyFuel uses a synthetic mixture of 02 and recycled exhaust gas where the 02 content may vary. This supplementary degree of freedom allows improved operation especially for low calorific fuels. Heavy fuel oil addition for low calorific combustibles can be omitted when using OxyFuel combustion. Application of alternative fuels (wood, waste wood, municipal waste, sewage sludge) in a 100-kW CFB plant is investigated in combination with process simulation.IntroductionOxyFuel combustion is discussed as one of the key technologies for the efficient separation of CO2 from combustion of fossil fuels (especially coal). Since coal plays only a minor role as primary energy source in Austria, the broadening of the scope towards OxyFuel of other fuels like biomass or waste fuels is necessary to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alternative fuels besides the large coal-oriented projects is interesting also from the strategic point of view. The presented project aims at the generation of knowledge in order to design and operate capture ready cofiring and waste/sludge incineration plants."

Jan 1, 2008

By Don Eby

The application of electric arc furnace smelting of lead, antimony, and tin bearing slag from a reverberatory furnace will be discussed. The selection procedure for the 4.0 MVA electric arc furnace in Indianapolis, Indiana is presented. The design criteria for the transformer, electrodes, refractories and associated equipment is presented. The operation of the furnace including chaJ:9ing, bullion tapping, slag tapping, ventilation, slag composition, metal recoveries, and toxic leach results of thra.1 away slag are discussed. Flow charts and the equipment specifications are given.

Jan 1, 1990

By Tuneo Funahashi

Sumitomo Shisaka Works has been treating EAF(Electric Arc Furnace) dust to recover zinc and lead in the Waelz Kiln process. Since its commencement of operation in 1977, many technical improvements have been successfully made to increase the production capacity and the zinc recovery rate. The EAF dust charge to the Waelz Kiln was increased from 35,000tly to 120,00OtIy, and the production of zinc oxide now amounts to 40,000tly. The zinc content in the clinker was decreased from 5% to less than I%, by the optimization of the kiln heat pattern with no accretion trouble. And the clinker has become more a valuable raw material for steel making. This paper describes the above progress ofthe SMM Waelz Kiln process operation at the Shisaka Works.

Jan 1, 1998

By Toshihide Takenaka, Takashi Matsui, Nao Murakami, Masahiro Kawakami

"Electrowinning of Ti have been investigated in a LiF-NaF-KF melt including K2TiF6 at 773-923K by applying electrochemical oxidation ofH2 gas as an anodic reaction. The cathodic behavior of titanium and the anodic behavior of H2 gas were studied by voltammetry in detail to clarify the electrolytic condition for the process. The electrowinning of Ti was carried out by potentiostatic _electrolysis. Steady electrolysis was achieved under the suitable electrolytic condition without breaking out the anode effect. Titanium metal was electrodeposited on a Ti cathode though the deposits were usually powdery. It is concluded that this process is potential if the morphology of the deposit can be improved.IntroductionTitanium has such good properties as high specific strength and high corrosion resistance. However, the availability of Ti has been limited because the price of Ti is much higher than those of other common metals, such as Fe and Al. The production process of Ti ingot from its ore is rather intricate so that the production cost is high. If the simpler process is developed, the production cost should be retrenched. Titanium metal is usually produced by the Kroll process, which consists of the electrowinning of Mg metal in molten salt and the chemical reduction of TiCl.i by Mg metal. The Kroll process is very elabrate, but not simple. Because the chemical reduction ofTiCl4 by Mg metal is highly exothermic, a considerable amount of energy is wasted.Titanium metal can be electrowon in molten salt bath in principle. A simpler and more effective process than the Kroll process may be realized by the direct electrowinning so that the electrowinning of Ti metal has been studied widely[ 1]. Some researchs progressed to a pilot plant stages [2], but the electrowinning of Ti has not been industrialized yet."

Jan 1, 2000

By Yuuki Hagio, Hiroyuki Tobo, Michihiro Kuwayama, Yasutaka Ta

"Reduction of CO2 emission is necessary to remedy global warming, however, promising approaches of CO2 separation require a large amount of energy. Molten slag, which is generated as by-product of steel production, has high temperature, but its energy has not been harnessed. To recover the thermal energy from the slag and to apply to separation of CO2 are economical and environmental conscious ways. We propose a new heat recovery system, in which, molten slag is solidified continuously on water-cooled roll and the solidified slag plates are charged into counter-current heat recovery equipment. In laboratory scale experiments, heat recovery ratio of more than 30% was acchived by controlling the thickness of slag.IntroductionThe steel industry in Japan has been working on the projects of ""Environmentally Harmonized Steelmaking Process Technology Development (COURSE50)"". COURSE50 aims at developing technologies to reduce CO2 emissions by approximately 30%. One of the main technologies is to capture and recover CO2 from blast furnace gas using chemical absorbents to regenerate CO2-laden chemical absorbents by separating CO2 from the absorbents. As one of the solutions, JFE Steel Corporation has been developing sensible heat recovery process from steelmaking slag. It is effective to recover and use unutilized high temperature waste heat within a steel plant as the thermal energy required."

Jan 1, 2012

This report presents overview of the authors' results of thermodynamical investigation of some important metallurgical processes and phenomena. Among them: carbo thermal reduction of silica, and boron oxide, silicon carbide obtaining from different precursors, investigations on copper and manganese ores processing, investigations on pollution from different sources. Special attention is paid-to thermodynamical approach to investigation and estimation of multi component multi element compositions stability, developed by the authors. Also are discussed some auxiliary but' important for the thermodynamical investigations issues.

Jan 1, 1997

By Zhang Chuanfu

The fibrous nickel oxide powder was prepared by the method of chemical precipitation and pyrolysis, that is, the NiO precursor was firstly precipitated from nickel ions solution with addition of oxalate salt and then the final NiO powder was obtained by pyrolysis of the prucursor. The effects of the pH, reaction temperature, reactant concentration, addition of surfactant on the morphology of the precursor particles were investigated. The influences of the various conditions, including the temperature and time, the air flow and the speed of the temperature increase on the morphology, average size and specific surface area of the NiO particles were also addressed. The fibrous NiO particles with IOO~ 120 in axis/diameter ratio and 5.5 m2/g of the specific surface area may be produced under certain operation conditions by this process.

Jan 1, 2003

By L. Salinas

Lance injection of gas and particles into a molten bath is currently practised in metallurgical processes (Mitsubishi lances for example). Several experimental and theorical studies have been conducted in the past on this topic. However, neither detailed calculations nor experimental studies of local flow patterns have been published. In the present work, a numerical simulation of the interaction of a gaseous vertical descending jet and a liquid surface was done, using the turbulence k-e model. There is a fair agreement between the calculated and the experimental values. The results of this study demonstrate that it is crucial that the gas jet velocity profile and turbulent characteristic are correctly formulated in order to correctly simulate the system.

Jan 1, 1999

By E. B. Freidina

We have investigated a new electrochemical process for preparing lead-calcium alloys. Calcium metal, reduced fiom a molten chloride mixture, forms an alloy with liquid lead cathode. The addition of calcium carbonate to conventional CaC12-NaCl electrolyte enables us to avoid chlorine production on the anode and replace it with oxygen and carbon dioxide. The ternary system CaClz-NaC1-CaCO3 has a range of melt compositions, where the electrolysis can be held below 650°C. In order to prevent the side reaction of carbon deposition on the cathode we have separated the anolyte from the catholyte with alumina diaphragm. The factors, which affect the level of impurities and the current efficiency of the process, are discussed.

Jan 1, 1999

By Mariana Barcelos, Frederico Muylaert Margem, Giulio Rodrigues Altoé, Pedro Amoy Netto, André Gomes, Sergio Neves Monteiro

Environmentally correct composites, made from natural fibers, are among the most investigated and applied today. In this paper, we investigate the mechanical behavior of polyester matrix composites reinforced with continuous fique fibers, through bending tensile tests. Specimens containing 0, 10, 20 and 30% in volume of fique fiber were aligned along the entire length of a mold to create plates of these composites, those plates were cut following the ASTM standard to obtained bending tests specimens. The test was conducted in a Instron Machine and the fractured specimens were analyzed by SEM, the results showed the increase in the materials tensile properties with the increase of fiber amount.

Jan 1, 2015