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By Ernest D. Mast

Noranda's Altonorte custom smelter, located in the 2nd region of Chile, 20 kilometres southeast of the city of Antofagasta, started operations in 1993. Presently, 1150 tonnes per day of new feed are smelted with an 85% sulphur capture. An oxy-fuel reverberatory furnace produces a 48%-55% copper matte that is treated in 13 ft. x 36 ft. (3..96m x 10.97m) Peirce-Smith converters (two hot and one blowing). Up to thirty percent of the new concentrate is smelted via dry concentrate injection into the converters. This paper reviews the development of the concentrate drying and injection system, and oxygen enrichment at Altonorte from start-up in 1995 to the present time. The relationship between oxygen enrichment and concentrate injection is reviewed from a theoretical and practical standpoint. Concentrate injection has improved the smelter's productivity and added flexibility to the operations. Due to the relatively high matte grades and the subsequent short converting times, maintaining consistent operations was difficult at times and the smelter has gone through a learning curve. Plant operating results and experiences are presented on the impact of concentrate injection in relation to: feed treatment, blowing times, revert generation, slag quality and refractory wear.

Jan 1, 1999

By Simon N. Lekakh, D. G. C. Robertson

A new integrated CFD-combined reactors approach is proposed for the description of processes in metallurgical vessels. CFD simulations were used to obtain the melt flow pattern in the vessels (ladle, tundish, and continuous caster mold). From these simulations, the characteristic curves were derived: (i) the residence time distribution curves (RTD) for flow-through systems (at tundish exit or at dendrite coherency surface in the mold) and (ii) the mixing curves for closed systems (ladle). In the next step, the melt flow was represented in a “combined reactors” system consisting of a combination of unit reactors (Plug Flow, Mixer, and Recirculated Volume). An inverse simulation was used to define the volumes of the reactor units and the melt flow rates between them by fitting to the characteristic curves from both methods (CFD and combined reactors). The suggested approach is demonstrated for multiple designs of Ar-stirred ladles, tundish, and SEN. This methodology can be used to enhance traditional post-processing CFD analysis and also as a tool for on-line process control.

Jan 1, 2014

By Y. Kumagai, F. A. Souza

"Electroless plating process has been used in many fields such as automobile and electronic industries. Solutions used in these processes must be disposed or treated. Commonly, in these solutions metal ions, organic materials and others chemicals are in very high concentration. It is very difficult to keep the environmental regulations for disposal of these materials, and the cost of the plating process becomes higher.The objective of this study was to investigate the recovery of components of those baths in order to decrease the cost of the plating process as well as to meet the environmental regulation.In this study the recovery metal ions, sulfate ions, phosphite ions and organic compounds were investigated. Organic compounds used in electroless plating solutions are the organic acids. In this work the solvent extraction of the most used organic acids included citric, lactic, succinic, tartaric and malic was studied. The solvent phase considered in these studies was ethyl acetate.About 95% of the metal ion was recovered by chemical plating onto mica powder. The hypophosphite remained is oxidized to phosphite and with the sulfate ion, both are recovered as calcium salts by selective precipitation in pH 7 and 2 respectively. Organic acids were recovered by solvent extraction using ethyl acetate as solvent phase and the best results were for lactic acid and succinic acid.Along with this study, was developed the analytical parameters to perform wastewater analysis by using Ion Chromatography, High Performance Liquid Chromatography (HPLC), Fourrier Transform Infrared Spectroscopy (FTIR). Ion chromatography was used to perform analysis of sulfate and phosphite ions in liquid matrix, HPLC was used to perform analysis of organic acids in liquid matrix and FTIR was used for characterization of the solids obtained in the recovery processes."

Jan 1, 1997

By M. J. Walker

The lead .smelter at Cominco's operations at Trail, B.C. has been undergoing. a modernization program since 1986. In that year a contract agreement was reached with German-based Lurgi GmbH which allows Cominco to construct and operate a lead smelter using Lurgi's QSL process. Cominco Engineering Services Ltd. (CESL), a subsidiary of Cominco Ltd., was contracted to provide project management, engineering, procurement and construction management? services for the project. The new smelter replaces the existing sinter-blast furnace plant ?and will have a capacity of up to 1601000 tonnes per year of refined lead. This new smelting proc.ess results in significant operating cost reductions and major environmental .improvements. Start-up of the new plant is scheduled for the fall of 1989. The metallurgy and the operating parameters, important to the design of the new smelter, are described together with projected deportments of lead, zinc, silver and minor metals. A plant description, will be given for the following major areas that make up the modernization project: the pressure filter operation for the preparation of ,zinc leach residues feed material, the QSL reactor and boiler itself, together with its feed system and process gas treatment, and the drossing plant with a new continuous drossing furnace and oxygen softening and thallium removal. Slag from the QSL reactor will be treated in existing slag furnaces until a subsequent second phase of the modernization is completed in the 1990s.

Jan 1, 1990

By P. J. Uggowitzer, K. Steinhoff, A. Wolf

"With the increasing acceptance of the Thixoforging process in the last few years, also the technical and commercial requirements for this forming technology and its components increased. So far, a great deal of work has been done in the development of an efficient process and control design. However, less attention has been paid to the development of new specifically tailored aluminum wrought alloys for this specific manufacturing process. · In this paper a new AlMgSi-alloy (A6082), optimized for the Thixoforging process, is presented. In the first part, the technical potential of the new alloy is specified by its microstructural evolution and flow characteristics in the semi-solid state. In the second part, the mechanical properties of thixoforged components of different conventional AlMgSi-alloys a (e illustrated · and compared to the new alloy.IntroductionSemi-solid metalworking, also known as semi-solid forming, is a hybrid manufacturing method that incorporates elements of both casting and forging. The key to the process relies on the peculiar flow behavior of slurries containing non-dendritic solid, which was first studied at the MIT by Flemings et al. [i], in the early 1970s. It was discovered, that if an alloy is uniformly stirred during freezing, discrete rounded particles of solid are formed rather than the normal dendrites, and the slurry is highly fluid (-5 Pas) up at least 50% solid. In addition, these slurries posses thixotropic flow characteristics: the viscosity is dependent on sheare rate and time. The more vigorously they are stirred, the more fluid they become. However, on standing the viscosity recovers and the material stiffens (-106 Pas).The semi-solid forming process exploits this phenomenon. In a first step, the required non-dentritical- microstructure is obtained by mechanical or electromagnetic stirring during primary solidification of the alloy. The stirred slurry is generally fully solidified as a feedstock billet and - in a second process step - reheated above the solidus temperature into the semi-solid state. In this condition, the thixotropic properties permit the material to be handled by robotic devices and transferred to a die (Thixocasting) or subjected to- a forming process by means of forging (Thixoforging). Owing to the shear stress which acts on the semisolid material during forming operation, the viscosity of the material is reduced attaining so the desired fluid-like flow characteristics."

Jan 1, 2000

By Francois Barthelat, Sam Goroshin, David Frost, Alexander Cappozi, Atefeh Nabavi

"In this study, a novel chromium–chromium sulfide cermet was produced by self-propagating high-temperature synthesis (SHS). Conventional techniques for manufacturing metal sulfides are complex, environmentally harmful, and not suitable for producing complex-shape articles. To overcome these disadvantages, a new method for the preparation of the metal-sulfur precursor charge is proposed, which can be described as reactive casting. The first cermet samples produced with the SHS process were found to be very porous, brittle, and have low mechanical strength. The possible sources for the generation of porosity were identified and analyzed and the process for manufacturing the cermet was modified. By improving the manufacturing process, the porosity inside the produced cermets was reduced from 70% to 12%.IntroductionMetal sulfide composites are in high demand in the chemical, metallurgical, and electrical industries because of their valuable characteristics such as hardness, semi-conductivity, electroluminescence, infrared transparency and catalytic properties. Current manufacturing methods for metal sulfides usually involve one of two different principal methods, including a complex multistage wet chemical process involving the precipitation of the corresponding salts from an aqueous solution with hydrogen sulfide, or hot sintering of the respective elemental reactant powders in a resistive furnace in a high-pressure inert or hydrogen-sulfide atmosphere [1, 2]. These conventional methods for synthesizing ceramic metal composites are complex, extremely time and energy consuming, environmentally harmful, and rarely able to manufacture articles with complex shapes. Therefore, in order to overcome these disadvantages, self-propagating high-temperature synthesis (SHS) was considered as an alternative method that offers significant improvements over the traditional cermet manufacturing methods [3]. SHS, which is a relatively new and attractive method for producing a wide range of advanced materials, is based on the self-sustaining feature of the highly exothermic reactions of the reactants. The SHS process results in high product purity, since the high temperatures generatedin the reaction cause any impurities to volatilize [4, 5]. SHS has low energy consumption and doesn’t require an external energy source and complex equipment, and it is self-contained [1, 5]. Since combustion synthesis has low power requirements, it is one of the few methods of materials synthesis that is feasible in outer space. Also, the process has a low cost and is capable of directly synthesizing articles with the desired shape, size and structure [5, 6]. The chemical reactions associated with SHS are typically completed in a few seconds leading to the formation of the condensed product. The high reaction rates and relatively rapid cooling in SHS reactions can avoid undesirable grain growth in products which often occurs with the conventional sintering method [3, 5, 7]. The traditional method for sample preparation in the SHS technique is to compact the reactant mixture powders in a steel die by a press to a typical density of about 80% of the theoretical maximum value, before igniting the mixture [8]. This method requires a large compression force to increase the green density and to minimize any pores in the green compact. To overcome these disadvantages, a new method for the preparation of the precursor charge in metal-sulfur by SHS is proposed which can be described as melt casting of a reactive mixture, or reactive casting in short."

Jan 1, 2012

By L. Escudero-Castejon, S. Sanchez-Segado, A. Jha, Y. Hara, S. Parirenyatwa

In a world where declining ore grades are increasingly common, it has become necessary to process low-grade feedstock. Carbothermic reduction in the presence of alkali (Na2CO3) has been adapted to beneficiate waste that contains titaniferous minerals (TiO2 ca. 12 wt%), in order to recover valuable constituents such as TiO2, Fe and V2O5. The waste from vanadium metal processing has environmental legacy as it leaves nearly 1 wt% V2O5 process waste, which is environmentally problematic due to V5+ ions in contact with water and soil. This investigation focuses on the kinetics and mechanism for alkali reduction of mineral waste bearing 10–12 wt% TiO2, which we studied in the 1073–1323 K range. The thermogravimetric analysis (TGA) technique was used to record weight loss data. Two distinct regimes demonstrated mixed-control kinetics: (1) at low temperatures the activation energy was found to be 199 kJ mol−1, which corresponds to the outward diffusion of O2− ions; and (2) at high temperatures the calculated value was 130 kJ mol−1, which is consistent with the activation energy for the outward diffusion of Fe2+ ions. The metallic iron, sodium titanate and sodium aluminosilicate phases that formed were characterised using X-ray powder diffraction (XPRD) and scanning electron microscopy (SEM) techniques, and their significance for metal recovery is explained.

Mar 1, 2017

By Claudio Parra De Lazzari

The determination of the governing step of the deoxidation rate and the effects of the hydrogen content of the mixtures (C), the diameter of the delivery orifice (4) and the Reynolds number of the orifice (Re.) on the product Av kjg were investigated. A,, is the total surface area of the interface between the bubbles and the melt and kjg is the mass transfer coefficient in the gas phase. The design of the experiments was based on a two level statistically fractionated, factorial planning. Oxygen in the melt was measured as a function of time. It was found that the governing step of the deoxidation rate was the transport of hydrogen in the gaseous phase and that {Ay kjg} increases with C, {o} and Reo.

Jan 1, 1997

By R. W. Harnmack

Hydrogen sulfide generated by the anaerobic respiration of sulfate-reducing bacteria was used to treat pH 2.2 water from the abandoned Rio Tinto copper mine in Nevada. The untreated water contained 550 mg/L Fe, 140 mg/L Al, 90 mg/L Cu, 80 mg/L Mn, 60 mg/L Zn, 4 mg/L Co, and 2 mg/L Ni. The bench-scale treatment system examined consisted of a bioreactor for H2S generation and three precipitator/clarifier units for metal sulfide precipitation and recovery. The treatment system reduced the concentrations of all metals except Mn to less than 0.1 mg/L. Manganese concentrations were reduced by 96 percent to 3.3 mg/L. A CUS/SO concentrate (33 pct Cu) and a ZnS/5° concentrate (28 pct Zn) were produced that may be suitable for metal recovery at existing smelters

Jan 1, 1994

By Masafumi Maeda

Our aim in this project was to develop a new copper refining technology utilizing pyrometallurgical treatment and a raw materials preparation technique. In the recycling process; raw material is not an idealized concentrate of copper sulfide but is composed of various types of scrap, industrial wastes such as sludge, ash and slag, and municipal wastes. Since we cannot expect oxidation heat in this process as in sulfide smelting, organic materials are viewed as an alternative energy source. Quality of the copper produced is targeted as 99.99% and an intermediate grade will also be marketable. To benefit the plant, rare metals and other nonferrous metals will also be recovered The overall system is described in this paper, specific topics outlined and preliminary research presented. Current Japanese technology for recycling copper based materials is briefly reviewed.

Jan 1, 1995

By J. E. Dutrizac

A mineralogical study of a weak acid leach residue from the Clarksville zinc plant of Savage Zinc Inc. was carried out. The study focused on Pb and Cd as these elements most significantly impact on the environmentally acceptable disposal of the residue. The residue consists of major amounts of bassanite, zinc ferrite and various Zn-Pb-Fe-Cd silicate species. Also present are lesser quantities of PbSO4, sphalerite, Fe2O3 quartz, Mn-Pb-Fe oxides, SrS04, (Pb,Sr)SO4 iron gel-silica gel, jarosite and Ti oxide. The principal Cd carriers are the zinc ferrite, which contains up to 9.00% Cd and likely accounts for -45% of the total Cd content of the residue, and the various silicate species which contain up to 6.97% Cd and account for about 45 % of the total Cd. The sphalerite is a minor Cd carrier containing an average of 0.35 % Cd and accounting for -5 % of the total Cd; the other carriers contribute only trace amounts to the total Cd content. The major Pb carriers are PbS04, Pb-bearing silicates and Mn-Pb-Fe oxides. Minor proportions of the total 1.09% Pb content of the residue are carried by SrS04 and (pb,Sr)S04' Trace Ph carriers include the iron gel-silica gel, Fe-Zn-AI oxide and bassanite. The residue after the toxicity characteristic leaching procedure (TCLP) is mineralogically very similar to the initial weak acid leach residue; the amounts of calcium sulphate are approximately the same in the two products. The principal Cd and Pb carriers are also the same as those noted in the initial residue, except that some dissolution and reprecipitation of Pb-Sr sulphate takes place. That the residue fails the TCLP test is likely a consequence of the superficial dissolution of Pb and Cd from species such as PbS04 or Zn-Pb-Fe-Cd silicate.

Jan 1, 1995

By L. Sh. Tsemekhman

A new technology for the treatment of copper nickel-containing concentrate after high-grade matte flotation to blister copper with the production of liquid silicate slags in a vertical autogenous unit with upper oxygen blow has been considered. The copper and nickel behavior in the process of sulphide copper concentrate interaction with silicate melt containing oxide copper has been studied. The general mechanisms of such interaction are found.

Jan 1, 2003

By K. J. Richards

The converting of copper mattes to blister copper has seen few technical advances since the introduction of batch furnaces using submerged tuyeres over a hundred years ago. The first side-blown converting vessel, operated by P. Manhes in 1882, was an offshoot of the 'Bessemer steelmaking process, and subsequent improvements in the conversion of molten mattes resulted In the Peirce-Smith converter, still the Industry standard today. While Peirce-Smith' converting has served the industry well since the early 1900!s, increasingly stringent environmental regulations, burgeoning energy costs, and a trend toward continuous processing have set the stage for a major improvement in this area of copper production. In contrast to a growing number of approaches for continuous converting using molten copper mattes, Kennecott is developing a process for treatment of solidified matte which allows improved' control, higher oxygen enrichment and a separation or decoupling of smelting and converting operations not possible with the other converting technologies. The new process known as Solid Matte Oxygen Converting, or SMOC, eliminates the need for molten matte transfers, minimizes fugitive emissions, and produces high strength SO2 off gases which substantially reduce offgas handling requirements. The SMOC process, despite additional matte solidification and size reduction steps, offers both capital and operating cost advantages for new smelters and the upgrading of existing plants, when compared with conventional converting technologies. Capital cost reductions of up to 35% in converting, gas handling, and sulfur fixation are indicated. Kennecott has successfully tested the new process concept and continued' development work is now under way to commercialize the technology. This paper reviews the limitations of batch copper converting with emphasis on the need for a continuous process, previous industry approaches to continuous converting of molten mattes, and the new Kennecott development.

Jan 1, 1983

By S. Ozbilen

"Al-Li binary alloys with nominal Li contents of0.15, 1.1and2.8 (in wt%) were aged naturally at room temperature for two months, aged at low temperatures ( 65 and 1 OOEC) for up to 2 months and aged artificially at 190EC for 4 days after water quenching to 25EC following solutionizing at 530EC for 20 minutes. Ageing behavior of these binary alloys were studied by Vicker's Hardness measurements and DSC thermal analysis. Thermal analysis results indicate the formation of GP zones of Al-Li system in Al-2.8wt%Li binary alloy. In the same alloy, rapid quenching from one phase region (a) gives rise to precipitation of small o' particles in a matrix (a) with still high supersaturation. During ageing of this alloy below lOOEC an additional transformation, i.e., GP zone formation occurs proceeding at a very high rate which is described on the basis of the theoretical analysis for the quenched Al-Li system proposed by Khachaturyan et al [6]. Ageing at temperatures below 11 OEC takes place slowly by the formation of small d' particles of lower thermal stability than the quenched-in d precipitates in addition to GP zones resulting in an increase in hardness compared to water quenched samples. During artificial ageing, GP zones transform by dissolution to d' precipitates while d' particles already in the microstructure coarsen during under aged condition at which hardness increases with time till peak aged condition.IntroductionIn binary Al-Li alloys the d' (Al3Li) fully coherent internally ordered inetastable phase of Li2 structure with a=0.4038d [1-5] forms homogeneously between 120 and 190EC before the formation of stable d' (A!Li) phase and cause the superior mechanical properties. This is due to an appreciable age hardening effect resulting because of the d' precipitation during ageing [1]. The response of d' to decomposition and its formation kinetics have been studied previously and it is believed that the decomposition of the a-supersaturated solid solution occurs in a two stage process; i.e., a 6 d' (Al3Li) 6 d(A!Li). Khachturyan et al [6] theoretically investigated precipitation of the d' phase and gave an interpretation of the transformation paths of the quenched Al-Li alloys. They predict that the disordered supersaturated solid solution congruently orders, and then the uniformly ordered solution decomposes into ordered regions that differ in Li-content. Finally, ordered d' phase forms in the disordered matrix."

Jan 1, 1998

By J. E. Allen

The trend in refractory technology for the copper and nickel industries has been to higher quality raw materials and improved processing technology. These changes have been dictated by the changes in pyrometallurgical processes in these industries. For example the introduction of flash smelting, reaction type smelting and auxiliary slag cleaning furnaces havedemanded better refractories materials. Extensive field applications and improved laboratory testing procedures have helped make this transition possible. Changes in refractory technology, primarily in basic refractories, are followed from the late fifties to the present and into the future.

Jan 1, 1994

By Steve Naruk

Microscopic point-count analyses, although time-consuming, provide detailed mineralogical information which is not obtainable by any other means. Such information can be invaluable for evaluating mill circuit behavior. In comparing two months of operation of a Cu-Pb-Zn sulfide flotation circuit, chemical analyses show that higher copper recoveries and concentrate grades were obtained from lower grade ore, but they provide no explanation of how the improvements were obtained. Quantitative micro-scopic analyses, on the other hand, show the following: 1. There was no change in the identity of the Cu-bearing minerals. 2. Increased copper recovery was achieved primarily by increased recovery of chalcopyrite middling particles. 3. The increased recovery of chalcopyrite middling particles also increased the amount of gangue entrained as locked particles. 4. Increased rejection of free gangue particles, particularly those finer than 25 microns in size, resulted in a net decrease in gangue content.

Jan 1, 1981

By Tengfei Qi, Liqiang Fan, Huiqing Tang

A new method to process the oolitic high phosphorus iron ore for phosphorus removal has been proposed in this research. It is an integration of direct reduction and melting separation with carbon-containing pellets prepared using biomass char. Experiments of direct reduction were preceded using a tubular furnace and three parameters were investigated and they were reduction temperature, biomass char adding ratio(molar ratio of carbon to oxygen） and atmosphere. Results show that the optimum condition is of reduction temperature is 1373 K, biomass adding ratio 0.9, PCO2/PCO 1.0 and reduction time 15~25 min. Under this condition, the reduced briquettes with a metallization of 75.0~80.0 % and a residual carbon content of 0.69~0.11 wt% could be obtained. Subsequent melting separation experiments were conducted using a Si-Mo high temperature furnace. Results show metal with phosphorus content of about 0.4 mass% could be obtained from the reduced sample.

Jan 1, 2015

By Yapeng Zhang, Zhiwen Shi, Chaoquan Yao, Fei Wang, Xinyu Li, Jianliang Zhang

A great deal of iron ores which have special elements have been applied in the sintering process with the decreasing of high-grade quality iron ores resources. In this paper, the laterite nickel ores were added into three different kinds of iron ores respectively to make liquid phase formation research by software of Factsage and high temperature characteristic sintering experiments. The results showed that the adding proportion of laterite nickel ores should be less than 15% when the high temperature properties of the mixing ores were well. Increasing the mixing ration of laterite nickel ores in the sintering blending would play an important role in the reduction of the sintering cost.

Jan 1, 2015

By Patricio Barrios

The Rio Tinto Metal (RTMetal) copper smelter, located 5 Km from Huelva, Spain, began operations in 1970. Since then a series of expansions and modifications have allowed a progressive increase in copper production. Environmental considerations having become increasingly important, environmental protection has come to represent an important aspect of the investments in production. As a result, modifications have been carried out in the two existing acid plants: -Modification of the RTM I gas cleaning section to closed circuit. -Substitution of cascade filters and acid lines. -Modification of the RTM I plant to double absorption. The Expansion and Environmental Improvement Project, completed end 1995, will allow 270,000 t Cu and 800,000 t H2SO4 to be produced yearly, at the same time achieving a decrease in specific and overall emissions. RTMetal's goal is to be an efficient smelter, with the avowed intention of respecting the environment and adopting the best available technologies.

Jan 1, 1996

By Huimin Lu, Qiang Li, Jingbo Xu

"The smelting reduction of V-Ti bearing beach placer by combined rotary hearth furnace and direct current arc furnace was studied in laboratory. It takes the aid of back propagation (BP) neural network theory to build the nonlinear mapping relations between the crucial process variables such as content of carbon, temperature and time and the degree of reduction. Then by the integrating BP neural network and genetic algorithm (GA), the optimized process parameters for the high degree of reduction were searched. The comparisons between experiment results and neural network simulation results show that GA-based on BP method can predict the degree of reduction with higher prediction accuracy. Calculations show that the integrated energy consumption of new technology is 580kgce/tHM, less than the current existing blast furnace.IntroductionThese V-Ti bearing beach placers (VTBBP) are secondary Fe-rich minerals formed by rivers, ocean waves, ocean tides and ocean currents on beach zones, their useful minerals are V-Ti magnetite ores. On Asia Pacific zone, such as Japan, China, Philippines, Indonesia, Australia and New Zealand, the VTBBP have large reserves and wide distribution. But so far, the VTBBP are not still comprehensively utilized. Therefore, in this paper, a combined rotary hearth furnace technology and arc furnace smelting method is studied for comprehensive utilization of the VTBBP. The main objective of this paper is to find optimum operation conditions for the production ofV-bearing iron and titania-rich slag from the VTBBP by means of the laboratory testing.Recently, neural network (NN) expected to be able to provide an effective tool because of its advantages, which describe nonlinear mapping relations. With the characteristics of strong selflearning, self-organization, robust error toleration and accurate nonlinear relation approximation, artificial neural network can be applied to nonlinear process modeling based on sufficient training. Back-propagation (BP) training algorithm is probably the frequently used one in practical application. Genetic algorithm has parallel search strategy and global optimization characteristics, which makes the trained neural network being higher classification accuracy and faster convergence speed. So it is necessary to combine neural network and genetic algorithm. The nonlinear relationship between input and output presented by NN and the global optimal function of GA are abroad applied in the engineering and scientific research [1, 2]. So these methods supply an efficient path to solve the above problems. At present, it is common to study the optimization of process parameters by orthogonal experimental design, the method combining neural network and genetic algorithm is a novel and better method than orthogonal experimental design. Tills study organized the above advantages to optimize the process parameters for comprehensive utilization of the VTBBP."

Jan 1, 2012