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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 Seshadri Seetharaman, Nurni N. Viswanathan, Haijuan Wang

"In order to make the stainless steel making process efficient and environment friendly, it is essential to minimize the loss of chromium to the slag phase. With a view to investigate the advantages of using CO2 to attain moderate oxygen partial pressures in the oxidant gas during the decarburizations of stainless steel, the present experiments were carried out to understand the oxidation kinetics of Fe-Cr alloys and Fe-V alloy with gas mixtures containing CO2. In the present work, the oxidation behavior of Fe-Cr and Fe-V was examined by thermogravimetric analysis (TGA). Various mixtures of O2 and CO2 were used as the oxidant gas and the oxidation rate was followed by the weight changes as a function of time.The experiments demonstrated that the oxidation rate is independent of temperature at present experimental situation, but has strongly related to the Cr-content of the alloy as well as the oxygen partial pressure in the oxidant gas mixture. The wetting of alumina by the iron drop and the change of the drop shape during the course of the oxidation were investigated by X-ray radiography."

Jan 1, 2010

By Alexander V. Suvorin, Vladyslav M. Sokolov

"The traditional technologies for production of the coprecipitated and deposited catalysts are analyzed from the standpoint of diversion of application of the feedstock and increase of efficiency for its usage. The options for return of the metals of spent catalysts to the catalysts production are described. The novel environmentally friendly and cost efficient approach for reutilization of the spent catalysts is realized in practice. It anticipates application along with spent catalysts of the waste generated in the catalytic productions. Reutilization of the Ni-containing catalysts is referred as an illustration. Introduction The recent development of large catalytic manufacturing for organic and inorganic synthesis, and petroleum refinery as well as for applied environmental catalysis has brought about increase and diversification of catalysts production. The generation of spent catalysts has been increased correspondently. The feedstock for production of catalysts is mostly metals in a form of nitrates, carbonates, hydroxides, hydroxydcarbonates. Sometimes salts of organic acids, of ammoniates, of chlorides and of sulphates occur. All these materials are scarce and expensive. So their repeated use by reutilization of spent catalysts is very actual issue. The traditional recycling the Fe-, Cr-, Ni-, Cu- or Zn-containing spent catalysts are carried out by pyrometallurgical reclamation of pure metals or alloys. They can not be used directly in production of catalysts [1, 2]. The hydrometallurgical approach is used for recycling spent catalysts with PGM, W, Mo, Co, Ni or Cu. It provides production of salts of these metals in a form of sulphates, chlorides, carbonates, hydroxydcarbonates and sometimes nitrates or ammoniates. Only a limited number of these salts can be used directly in production of catalysts. Material losses during catalysts production The basic feedstock for manufacturing coprecipitated and deposited catalysts that may be produced from the spent catalysts is aqueous solutions of metals nitrates. Their production is based on application of nitric acid as a dissolvent. About half of it is lost with the flue gases in a form of nitrates vapor and nitrogen oxides (II, IV). The last compound is generated by reaction:"

Jan 1, 2008

By Chris Doyle

From 1997-2000. PT INCO undertook the Fourth Line Expansion Project (FLEX) to increase annual production rates from 90-100 to 150 Mlbs Ni/year (68,000 MT Ni/yr). In 2003, PT INCO nickel production underwent a major sustainable step jump that finally exceeded the targeted rate. This paper presents the changes that led to this achievement. The focus of mining changed. Improving Ni grade was important but only if electric furnace feed met target chemistry so that on-specification slag could be produced. The intensity of diamond core drilling for exploration was dramatically upgraded, mine planning strategy was totally re- vamped and an ore chemistry quality assurance team was formed. In the processing plant, measurement systems were upgraded for better control. Teamwork between sections vastly improved. The final step jump in production occurred when the fifth hydro-electric power generator was added to the furnace grid to allow the power-starved furnaces to cruise in operation at 70+ MW. Keywords: Free cash flow, Ore Chemistry, Measure, Control, Improve

Jan 1, 2004

By Chenhui Liu, Hong-ying Xia, Bingguo Liu, Wei Li, Jinhui Peng, Libo Zhang

"Dielectric property is an important limiting factor in the development of microwave processing of minerals and ores. In this study, we used an open-ended coaxial sensor method to measure the complex permittivity of an ilmenite concentrate (41%TiC>2) and microwave absorption properties from room temperature to 100°C. The results show that the dielectric constant, loss factor and loss tangent increase with temperature rising at 2.45GHz. Microwave absorption properties of this ore are highly dependent on temperature and frequency. Ilmenite concentrate can be used as raw materials to prepare wideband microwave absorbing material. The research will be helpful in explaining the thermal running of microwave dielectric heating the ilmenite concentrate.IntroductionAs the sources of high-grade titanic mineral are decreasing worldwide, the utilization of low-grade minerals such as ilmenite has attracted more attention [1,2]. Because Panzhihua ilmenite has complex minerals and high contents of MgO, CaO, S1O2 , it is difficult to upgrade the ilmenite to titanium-rich slag and farther produce synthetic rutile and titanium dioxide pigment [3]. Therefore, it is desirable to develop new technology for processing ilmenite ore [4]."

Jan 1, 2012

By Ali S. Al-Watban

"In this paper, the room temperature friction and deformation properties of various polycrystalline diamonds; i.e. aggregates of diamond crystals with a ""binder"" phase of cobalt and a polycrystalline coating produced by a chemical vapour deposition processes (CVD) were studied when softer metallic and ceramic sliders were used. The experiments were conducted· at relatively low sliding speeds (10 mm/min), in a vacuum of 10-5 mbr after having cleaned the specimen surfaces by out-gassing them for about 30 min at 800 °C. As a result of increasing the number of traversals significant wear of the coated diamond by softer metallic sliders (aluminium and mild steel) was observed. With ceramic sliders, it is shown that the multiple traversals result in the formation of wear groove. With diamond silicon carbide, high friction and adhesion lead to significant metal transfer which then pre-empts cumulative deformation of the harder materials. With the diamond-cobalt composite, the friction is surprisingly low, there accumulation of wear debris on the tip of the slider but no permanent transfer of metal and the harder specimen is not damaged even after 5000 traversal.IntroductionPolycrystalline diamond is mainly produced as tool materials for the machining of hard metals and composites. Thus, the sliding friction and wear resistance are amongst the most important properties relevant to those applications.During cutting by PCD the wear mechanism is mostly influenced by the chemical affinity between the tool material and the workpiece. For example, diamond based materials are not recommended for machining ferrous materials because carbon is highly solubie in iron: This leads to the graphitisation of diamond particles and hence a high rate of diffusion wear is observed (Brookes and Lambert, 1982)."

Jan 1, 2000

By T. Mutoh

Tellurium in raw slime has recently been recovered as copper telluride in Onahama Smelter & Refinery. The slime is decopperized with sulfuric acid solution in conventional leaching tanks. The pregnant leach solution containing 45 g/l of copper and 1 g/l of tellurium is introduced to a copper telluride recovering reactor. The tail solution from the reactor containing less than 20 mg/l of tellurium is recycled directly to circulation tanks of copper electrolysis. The impurities of the product copper telluride is kept below 1% without any purification.

Jan 1, 1990

By H. Kohno

The Onahama No.3 tankhouse started commercial operation in early 1973, with the capacity of 8,500 metric tons per month. When the No.3 tankhouse was constructed, the starter sheet stripping section was rebuilt at the No.2 tankhouse and electrolyte purification section was expanded. The previous AIME paper in 1976 described the design principles of the No.3 tankhouse and its layout, This paper describes the starter sheet stripping machine in the No.2 tankhouse and the electrodes handling system in the No.3 tankhouse and all these equipments were developed for the operation of the No.3 tankhouse. A Hazelette continuous casting machine was also introduced in order to cast thin anodes with accurate shape. Owing to the adoption of thin anodes, gold, silver and copper inventory is reduced by 40%. Jumbo tanks and newly developed mechanical equipments were adopted and no work on cells during pulling up operation was achieved. Using thin anodes with accurate shape, inspection work was completely abolished while maintaining high current efficiency and high cathode quality. Labor cost was reduced by 70% and only six operaters can produce? 8,500 metric tons of cathodes per month. The same new electrolysis process is appreciated and has been used as a newly built independent tankhouse by Kidd Creek Mines Ltd., in Canada in 1981 with excellent results

Jan 1, 1987

By Kenneth P. Michalek, James E. Kelly, Jonathan A. Dantzig

"Many investigations have been reported regarding the simulation of continuous casting with emphasis on in-mold heat transfer. These analyses have been limited, however, because they require either estimation or measurement of the characteristic heat transfer between the ingot and the mold. In this paper, a self-consistent model 'is presented for calculating the heat transfer between a solidifying continuous casting and the mold, in the context of the continuous casting of steel. Using both thermal and stress analyses, the air gap formed during continuous casting is calculated and used to compute the heat transfer coefficients. Iteration between the thermal and stress analyses is used to determine a self-consistent solution. IntroductionThe continuous casting process for steel is illustrated schematically in Fig. 1. Molten steel is tapped into a tundish from which it flows at a controlled rate into the continuous casting mold. The initial shell of the casting forms in the mold by transfer of heat from the metal through the mold wall to the cooling water. The remainder of the casting is solidified by application of water sprays, and/or radiation cooling below the mold.Heat transfer in the mold portion of the process is important because it controls the formation of various defects which are deleterious to subsequent processing. Examples of defects formed in this region are surface irregularities, such as cold folding and oscillation marks, and more serious defects, such as longitudinal or transverse cracks. A more catastrophic problem which may occur is a breakout, in which the shell ruptures and molten steel is discharged in an uncontrolled way."

Jan 1, 1986

By Levente Becze

The zinc bottom dross is obtained as a by-product from hot dip galvanizing operations and contains at least 92 % zinc, which is recycled mainly by pyrometallurgical processes. The overall costs of such a treatment, however, are often relatively high, and the very strict environmental protection regulations might also cause additional difficulties for the high temperature procedures in the future. Therefore, a novel hydro-electrometallurgical process has been developed in our laboratory, by which one can reclaim zinc of high purity, while attempting to achieve low energy consumption and making allowances for all the environmental restrictions. This aqueous processing technique, based on electrolytic refining in a cell equipped with anion-exchange membrane to separate the anode and cathode compartments, allows the indirect purification of the anolyte. Zinc is dissolved from the anode along with some of the impurity elements, while the intermetallic compounds (Fe-Zn, Fe-AI- Zn) are accumulated in the anode slime.

Jan 1, 2003

By W. K. Tolley

The U.S. Bureau of Mines (USBM) is currently investigating improved technology for mineral flotation. A variable often neglected in flotation control is redox potential. The use of redox control is illustrated by the separation of molybdenite from chalcopyrite. Laboratory testing showed that redox potential had a greater effect on product quality than collector addition. A significant need in froth flotation is greater reliability of the sensors used in measuring and controlling redox potential in mineral slurries. The USBM has developed an automated method for removing scale and reconditioning gold redox-sensing electrodes. Fouled electrodes are anodically polarized to 1.2 V versus the AglAgCI reference potential to remove scale. The electrodes then are conditioned by a brief potentiodynamic treatment to re-establish electrochemical equilibrium. In laboratory tests, this technique removed calcarious deposits from gold electrodes and reconditioned them for useful service in approximately 10 min. In plant practice, this technique would obviate the need for plant operators to manually polish electrodes, and also should result in greater reliability in redox measurements. Inexpensive, automated equipment to condition electrodes in a plant setting is described.

Jan 1, 1995

By James T. Skoch

With the ongoing pressure on the secondary aluminum business to limit the amount of waste generated from processing aluminum dross, it becomes very advantageous to preprocess the dross to reduce waste. The advantage of preprocessing is that it significantly reduces the oxides and salt cake generated when melted. Various products can be produced from the oxides for the steel industry. The following paper will demonstrate that removal of oxide fines before melting will result in large volumes of material not being landfilled. We will show that the end result of this technology is to significantly reduce the amount of salt cake sent to a landfill while maximizing the recyclability of the aluminum dross.

Jan 1, 1995

"Hematite pellets were electro-deoxidized to iron in molten sodium hydroxide to produce iron containing about 10-wt % oxygen. The anodic reaction was the evolution of oxygen on an inert nickel anode. Before the electrochemical reaction, there is a reaction between sodium hydroxide and ferric oxide to form sodium ferrite and, in order to compensate for the reduction in sodium oxide content, 1 wt % sodium oxide is added to the melt. In a laboratory cell, the cell voltage was 1.7 V with a current density of 5000 A m-2, a current efficiency of 90% and an energy consumption of 2.8 kWh kg-1.Introduction The iron and steel industry contributes about 2.3 bn tonnes/annum of the carbon dioxide to the atmosphere, which is about 10% of the total, and some believe that, in order to prevent a catastrophic rise in the earth’s temperature, carbon dioxide emissions must be reduced by 50% come 2050. However, by 2050, it is likely that the iron and steel industry would have grown significantly so that the production may have risen to 2 or 3 bn tonnes/year so in order to meet the 50 % reduction on today’s figure, the carbon dioxide may have to be reduced to 25% or less, which is a very demanding requirement. There are probably three ways of reducing the carbon dioxide output:1. By capture and sequestration, but this may be technically very demanding.2. Reduction using hydrogen in place of carbon."

Jan 1, 2009

By A. V. Tarasov

In the course of research aimed at improving the performance of the Vanyukov smelting process (VP) for treating sulfur raw materials in a pilot-scale furnace it has been found that an increase in the calcium oxide content up to 12% to 14% in case of smelting to produce high-grade matte results in a decrease in the copper content of slag by 0.05% to 0.3%. The residual copper content of slag can be computed by a formula taking into account an increase in the calcium oxide content of the feed material and that in the slag. In the course of research for improving the performance of the zinc-containing slag fuming process with blowing of the slag bath with combustion products of natural gas it has been found that the silica and calcium oxide contents have an effect on the degree of zinc sublimation. In case of slag containing 24.4% SiO₂ and 6.95% CaO by weight (SiO₂:CaO = 3.51), the residual zinc content of slag was 3.25%. The minimum residual zinc content of 1.95% was obtained in case of slag containing 22.5% SiO₂ and 14.5% CaO by weight (SiO₂:CaO = 1.55). An increase in the CaO content of slag up to 16% by weight with a ratio of SiO₂:CaO = 1.25 to 1.35 permits minimization of zinc losses in slag by achieving a residual zinc content of final slag in the order of 1%.

Jan 1, 2006

By M Philip Schwarz

"This paper reviews the status of computational modelling of a variety of common metals reduction processes, namely the blast furnace, rotary kiln and fluidised bed, and one new process not yet commercialised, namely smelting-reduction as in the HIsmelt Process. In each case, the last decade has seen the emergence of the capability to simulate the processes using multi-phase reacting computational fluid dynamics techniques. In some cases this capability is still in the process of being developed, and the next few years will see the maturing of the modelling techniques. As they become established, it will be possible to apply them to further refine the older technologies such as blast furnaces and rotary kilns, and assist in the optimisation, commercialisation and acceptance of the newer technologies such as fluidised bed and molten bath reduction. The development of a computational fluid dynamic model of bath smelting-reduction is described in some detail to illustrate how a large number of complex and interacting phenomena can be successfully simulated within a CFD framework. IntroductionPyrometallurgical reduction processes, such as the iron blast furnace, have become increasing more sophisticated through the centuries, so that today they are often highly efficient. There are continuing pressures, however, to refine existing processes and develop new ones. The imperatives are often economic, given that the long-term trend in the price of metals is always downward. In recent times, there has been the additional need to improve the environmental impact of metal production. Given that they almost inevitably require the use of carbon, metal reduction processes are large sources of greenhouse gases, and even a relatively small improvement in efficiency can be valuable in reducing CO2 production. Local environmental issues, such as the need to control of particulate emissions, are also driving incremental improvements in equipment.In addition to the economic and environmental drivers mentioned above, new process development is also being driven by the need to process new ores, and the need to produce unrefined metal in a form more compatible with alternative routes for downstream processing. An example of the latter is the production of DR! (Direct Reduced Iron) as a feed for EAF Electric Arc Furnace) in mini-mills.Further improvement of processes that have already been honed by continual plant experimentation over many years is not an easy task. To deliver further gains in efficiency, throughput, or product quality requires a highly sophisticated tool: one such tool· is computational modelling."

Jan 1, 2001

By Andreas Siegmund

During the decade of the nineties the conventional method of primary lead smelting (sinter machine/blast furnace) was successfully challenged by the introduction of novel direct and continuous smelting processes. In combination with a significant shift in market structure, as well as more stringent government regulations these modem technological innovations like the QSL, Kivcet, and Isa/Ausmelt processes became more than major competitors. They have proven to be economically and environmentally viable. The intensification of the metallurgical reaction by applying oxygen enriched or pure oxygen bath or flash smelting principles resulted in cost savings and a higher flexibility with respect to raw materials and additives usage. By synchronizing individual auxiliary plant sections with the smelting process a virtually waste- free production and low-emission mode of operation with nearly optimum energy exploitation is achieved. The primary lead industry will gradually substitute the sinter -blast furnace operation with novel high-energy efficient technologies in the new millennium.

Jan 1, 2003

By Wenliang Cao, Jidong Li, Mingjie Zhang, Yiyong Wang

In CaC12-CaF 2 System, we studied the electrode process and discharge mechanism of preparation of Al-Ca alloys by fused salt electrolysis with CaO as raw material. The change of back electromotive force after adding CaO was measured by continuous pulse oscillograph method and the discharge process mechanism was also investigated by cyclic voltammetry. The finial results indicate that back electromotive force decreases by 0.6V after CaO of 1 % is added and there was a peak of oxidation current ahead of the potential at which the negative chlorine ions precipitated. According to thermodynamic calculation, it was determined that current peak was caused by the CO2 produced by 0 2 - ionic discharge due to CaO addition.

Jan 1, 2014

By Huanyu Zhang, Quanqiang Ma, Huiqing Tang

Improvement of the coke quality for blast furnace (BF) iron making by hydrothermal oxidation treatment on coke quality was investigated. Results show that, under subcritical condition, sulfur removal rate is 15% and the weight loss is 3%; under supercritical condition, both sulfur removal rate and mass loss rate increase with the increase of H2O2 concentration. In the experimental conditions, sulfur removal rate and mass loss rates were 45% and 17%, respectively. Hydrothermal oxidation treatment could reduce the CO2 reactivity of the coke and the treatment under supercritical condition is more effective. Hydrothermal oxidation treatment could improve the graphitization of the coke and smoothness of pore boundary in the coke and the treatment under supercritical condition is more effective.

Jan 1, 2016

By T. W. Turk

In May 1984, Davy McKee Corporation was awarded a contract for engineering design, procurement assistance, project management and startup services for two gold recovery plants? in the People's, Republic of China (PRC). The basic design of these two projects was to be accomplished by a combined effort of the Chinese and Davy McKee Corporation (DMC). The, design goals were to provide a state-of-the art plant while maintaining Chinese standards and design practices whenever possible. Chinese-manufactured equipment was to be used as much as possible. This paper discusses the project organization and procedures developed to accomplish the design goals, the process selection and design, and the selection and procurement of equipment outside of the PRC. Design development for grinding, leaching and carbon adsorption, and gold recovery are discussed in detail. The major goal of process selection and design was to provide common criteria for both plants. Equipment .sizing and selection was identical for carbon-in-leach adsorption, gold recovery, acid washing, and carboo regeneration for both plants. Of special importance is the design of the wastewater treatment system. Due to the cl0se proximity of a major population area, slurry discharging from these mines must be treated to meet drinking water standards. The process development and design of this system is also discussed in detail.

Jan 1, 1989

By Itavahn Alves da Silva, Izabela Diniz Duarte, Carlos Antonio da Silva, Varadarajan Seshadri

Mathematical modeling using computational fluid dynamics has been employed to assess the thermal losses in a steelmaking ladle. Thermal losses lead to thermal stratification and convective flow inside the ladle. The effects of preheating, mineralogical and physical characteristics of the lining as well as thickness of slag cover have been studied and the results obtained from application of the model have been discussed.

Jan 1, 2016