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By P. Louis

Gécamines is the world largest cobalt producer with about 60 % of the Western World production. During the last ten years, its annual production varied from 5,400 to 14,600 t/year. The actual cobalt production capacity of Gécarnines is 18,000 t/year and could be increased in the near future if necessary. Cobalt is presently produced at the Shituru plant by an old in-pulp electrolysis process and in Luilu, by electrolysis of a clear weakly acidic solution. The Shituru Cobalt quality is lower than the Luilu one. For that reason, part of the Shituru Cobalt is fire refined and cast into granules. Large efforts have been succesfully accomplished to improve the cobalt quality. This has been made possible by a better knowledge of the purification processes and of the electrolysis parameters.

Jan 1, 1988

By Manuel Zamalloa

The outstanding metallurgical performance of the Noranda continuous converter (NCv) in operation since November 1997 has allowed the company to meet production and environmental targets. This achievement positions this new technology as a strong alternative continuous converting technology for copper production. Knowledge of slag chemistry has been important in this respect. The purpose of this paper is to discuss the effect of key parameters including temperature, oxygen potential, slag composition and levels of copper oxide in slag on the conditions leading to magnetite precipitation, as well as on the conditions affecting the liquidus ranges of NCv slag. The above variables are evaluated using industrial data and thermodynamic predictions. Practical implications of customizing operational fluxing procedures to determine optimum operating windows are also discussed.

Jan 1, 1999

By D. M. Jones

In May 1999 the first campaign of the BHP San Manuel flash smelting furnace (FSF) will be concluded after having set world records for both campaign length and tonnage smelted for an Outokumpu copper flash smelting furnace. This paper reviews planned process and equipment modifications including: The installation of a new 36,000 mt concentrate storage facility; replacement of the existing dryer electrostatic precipitator with a baghouse; modification of the FSF dry charge bin and feed system to achieve mass flow and uniform feed to the concentrate burner; modifications to the FSF and its ancillary cooling systems; modifications to the waste heat boiler and offgas handling system to increase gas handling capacity and improve process efficiency;- and improvements to the FSF fugitive gas collection system. A brief review of the planning and execution of the scheduled 45 day shutdown is also given.

Jan 1, 1999

By Dieter Offenthaler

Catalysts used in petroleum industry often contain valuable amounts of PGMs. The typical recycling route for those materials is the pyrometallurgical one, but this treatment way offers limited flexibility with respect to small charge weights. A new process, combining a pyrometallurgical pre-treatment step of the ceramic carriers with a hydrometallurgical leaching procedure overcomes this disadvantage. It not only allows the economical treatment of even very small charge weights, but also gives the possibility to maximize the PGM yield by individually adapting the process to the different charge materials. Due to an ingenious process design, where all leaching agents and effluents are recycled in a closed loop and therefore no waste waters leave the process, process operation becomes very economical. However, the temperature-time-regime in the pyrometallurgical pre-treatment step is of major importance for the success of the whole process. Therefore various investigations have been done to identify how the different process variables in the pyrometallurgical pre-treatment influence the subsequent leaching procedure. It turned out, that the adjustment of the correct phase-modification in the ceramic carrier materials during the pyrometallurgical treatment is the key factor of this process step. Although it is a troublesome issue to exactly adjust the correct phase modifications, it is the prerequisite to take advantage of the benefits of this new process concept.

Jan 1, 2006

By Bingliang Gao, Junli Xu, Michal Korenko, Jinzhao Guan, Liangxing Li, Zhongning Shi, Zhaowen Wang, Aimin Liu

Al-Si alloy, a precursor of solar grade silicon, was prepared by direct electrolysis in cryolite molten salt at 950 oC using high purity silica as material, liquid aluminum as the cathode and high purity graphite as the anode. The electrochemical behavior of Si(IV) ion was investigated using cyclic voltammetry method. The electrolysis products were characterized by XRD, SEM/EDS and ICP. The results indicate that the reduction process of Si(IV) on tungsten electrode is a two-step process and there is about 0.6 V gap between the two steps. The contents of boron and phosphorus in the aluminum-silicon alloy are 3 ppmw and 8 ppmw, which will make the directional solidification purification effectively and reduce the cost of preparation solar grade silicon from metallurgical grade silicon.

Jan 1, 2015

By P. Hanniala

In the day-to-day life the copper business of today is influenced directly by the ever-increasing general concern about the environment. In addition to that the inherent shortcomings of the copper smelting business, have since many years been the falling real price level of the metals and the relatively high initial capital investments required for the production units. These shortcomings have been compensated for by high productivity, low specific operating costs, low metal inventory and unbeatable technological superiority. Thus today more than 50 % of the world primary copper is today produced by utilizing Outokumpu Flash Smelting Technology. This figure is expected to grow at an increasing speed in the near future. Characteristic for the Outokumpu Flash Smelting technology is high flexibility for a wide grade of concentrates and the highest sulfur capture owing to at the same time competitive investment and operational costs. The Flash Converting technology offers new options for copper production and optimization of the mine- concentrator-smelter production chain. In the following years it is expected that the trend in copper making is that higher grade concentrates are produced at the mines. Thus increasing amount of high grade concentrate will be available for direct-to- blister Flash Smelting causing an overall cost reduction in copper smelting i.e. both in capital and operational costs. In the '90s new technologies based on Outokumpu Flash Smelting technology have been taken into operation, thus eliminating the non-continuous Peirce-Smith converting process step. New innovative solutions have been used in the latest projects, as in Kennecott Utah Copper, where the new Kennecott-Outokumpu Flash Converting process was started up in 1995. Also, in 1995 the new DON process was started at Outokumpu Harjavalta nickel smelter followed by the Fortaleza nickel smelter in Brazil in 1997. The aim of the continuous development work at Outokumpu has been the expansion of the direct-to-blister process towards lower grade concentrates. The most recent example of this is the start-up at the Olympic Dam smelter in Australia, where the existing direct-to-blister Flash Smelting furnace was replaced with a new one having a capacity of 200 000 t blister copper per annum in just one smelting step.

Jan 1, 1999

By Peng ZANG, Qihang Liu

Experimental work was conducted to determine the relationships of coal char conversion with temperature and heat absorption. The results show that at an earlier stage of the coke forming process, lump coal would absorb large amounts of heat but the increase of high temperature strength of lump coal was not significant. Contrarily, the lump coal’s high temperature strength was greatly improved at later stage of coke forming process. A number of residual coal was found in most tuyere coke samples illustrating that the lump coals added in the melter gasifier were not completely transformed into coke when they arrived at the tuyere region. The results indicate that the improvement of lump coal’s high temperature performance is limited in the melting gasifier by the low coke forming rate which could become the core factor of fines generation of lump coal in the melting gasifier.

Jan 1, 2016

By Rongshan Qin, Dengfu Chen, Yan Zhao, Mingtu Ma, Yang Li, Xinming Wan

A two dimensional cellular automaton (CA) model coupled with finite element (FE) method has been developed for simulating the formation of solidified microstructure during beam blank continuous casting, which represents columnar and equiaxed dendrites growth in the case of detailed secondary cooling boundary conditions. In this model, a new adaptive mesh division is proposed to couple CA cubic lattice and irregular FE mesh of beam blank. A double-accuracy liner interpolation method is employed to obtain micro CA temperature field via macro FE calculation. The nucleation process and the velocity of dendrite tip are calculated by continuous nucleation model and KGT model, respectively. Moreover, the preferred orientation of dendrite growth is determined using a probabilistic model. The effects of super heat and casting speed on the microstructure characteristics are analyzed. This model can be applied to optimize processing parameters for beam blank continuous casting basing on microstructure evaluation.

Jan 1, 2015

By Xiang Lan

A strain of Thiobacillus ferruuxidans No. 8 was isolated from the acidic mine water of an arsenopyrite deposit, South China. It has been found from the experimental results that the growth of bacteria was inhibited by flotation agents. The order of toxic effect of different flotation agents on the growth of Thiobacillus ferrooxidans is ethyl xanthate > butyat ammonium aerofloat > butyl xanthate ? isobutyt xauthate >? flother No. 2 oil. The bioteaching treatment of arsenic and antimony-bearing gold concentrate in Longshan mine, Hunan province, China, was influenced considerably by the presence of flotation agents. The possible causes of the influence of flotation agents were discussed and an improved method was suggested.

Jan 1, 1991

By Gabriel Riveros, Ariel Balocchi, Andrzej Warczok, Daniel Smith

Blister copper from converting of copper matte is processed by fire refining prior to electrorefining. The fire refining consists of two steps: copper oxidation with impurities slagging and copper reduction. The classical batch process is carried out in vascular or reverberatory furnaces called anode furnaces. A new process for continuous copper fire refining has been proposed. The copper flows through two reactors in cascade, where is oxidized and reduced. The flow of a liquid copper through a ceramic packed bed increases the surface area and the rate of oxidation as well as the rate of reduction in the packed bed of charcoal. Mathematical modelling allowed for the design of a laboratory scale demonstration installation and industrial-pilot installation in Hernan Videla Lira Smelter (Paipote). The results have demonstrated the process feasibility and flexibility in operation.

Jan 1, 2009

By C. K. Gupta

Electrometallurgical processes have a definite place in the extraction technology of rare earth metals and alloys. Some of the advantages of the molten-salt electrometallurgical processes include fast electrode reaction, providing accurately controlled large amount of energy to a relatively small reactor volume, negligible over voltage, simplicity of operation, and possibility of accomplishing continuous or semicontinuoue operations. This paper provides a vivid account of the theoretical and practical aspects of electrometallurgical processes for the production and processing of some of the rare earth metals and alloys. Reference has been drawn to the work reported on electrometallurgical processes as applied to the preparation of lanthanum, cerium and misch metal from author's laboratory.

Jan 1, 1992

By Mahin Rameshni

WorleyParsons innovative SO2 reduction process efficiently recovers sulfur from SO2 streams. Effluent gases from ore roasters and smelters and coal-fired power plants can be treated to reduce sulfur emissions. This exciting new process is an innovative combination of well-established processes of reaction of CH4 and sulfur vapor to produce CS2, followed by catalytic hydrolysis of CS2 to H2S, and Claus reaction of H2S and SO2 to sulfur. Key advantages are lower fuel consumption, reduced emissions, better product sulfur quality and better operational stability. The Production of elemental sulfur from SO2 is being called Rameshni SO2 Reduction (RSR) and it is patent pending.

Jan 1, 2006

By Józef Czernecki

The Polish copper concentrates are characterised by low content of sulphur and iron. At KGHM Polska Miedz S.A. two copper production technologies are in use. The shaft furnace process is used at the Legnica Copper Smelter and the Glogów I Copper Smelter. A single-stage direct to blister Outokumpu flash smelting process is used at the- Glogów II Copper Smelter. Melting copper concentrates in the shaft furnaces is carried out in a reducing atmosphere and the product obtained is a matte. Instead, a result of melting copper concentrates by an oxidising flash process blister copper of a quality similar to that of converter copper is obtained. The annual copper production at KGHM Polska Miedz S.A. exceeds 450,000 tons. Another important metal is silver produced from slimes from copper electrolysis (about 1000 t/y). Moreover, such metals as Pb, Ni, Se, As, Au and other precious metals, including Pt and Pd, are recovered from various semiproducts. This paper presents technological flow sheet of the copper production in plants using the shaft furnaces and in another plant in which a single-state flash process is applied. Characteristics of products, methods of their utilisation, main parameters of particular technological operations, and advantages and shortcomings of the solution applied are presented. There are also discussed: the natural environment protection as well as directions of the KGHM Polska Miedz S.A. plants modernisation.

Jan 1, 1999

By C. G. Anderson

Throughout the world, there are many orebodies or materials which have significant value but also contain arsenic. As regulations on the transport, exposure, disposition and emission of arsenic have become more stringent; it has become increasingly more difficult to derive the values from these resources. This paper will outline the fundamentals of alkaline sulfide hydrometallurgy and its successful application to arsenic bearing ores, concentrates and materials.

Jan 1, 2005

By Jacob Bummer, Greg Roset, Dayle Flynn

"IntroductionStillwater Mining Company operates a Precious Metals Smelter (PMS) located in Columbus, Montana USA. The PMS processes iron, copper, and nickel sulfide bearing concentrates containing platinum, palladium, gold, and rhodium. The concentrates are produced from two mines in the Beartooth Mountains located in south central Montana. The PMS utilizes a 7.5 megawatt 3-in line electric furnace to smelt the concentrates, and two Top Blown Rotary Converters (TBRC's) to remove iron. In addition to the mine concentrates, the PMS also processes various forms of Platinum Group Metal (PGM) bearing recycled catalyst. The sulfide matte produced within the electric furnace and TBRC's acts as a collector for the PGMs. Throughout the operation of the PMS, there are three different forms of molten material that are processed through the Stillwater Granulation system: TBRC matte, TBRC slag, and electric furnace matte. This paper describes the operation of this granulation system.Tapping the FurnaceWhen a sufficient level of molten PGM bearing matte has been reached within the inner volume of the electric furnace, the molten material is ""Tapped"". Tapping requires drilling into the electric furnace until reaching the molten matte phase. The matte phase will drain out of the drilled hole through a graphite launder into a 5 ton refractory lined ladle. Once the ladle is full, the tap is plugged with a mud gun."

Jan 1, 2012

By Honggang Zhong, Xin Cao, Qijie Zhai, Hongmei Song, Congsen Wu, Cheng Zhang, Jingzheng Ye

"The influence of superheat on the solidification structure and ferrite/austenite phase transformation of a novel lean duplex stainless steel (DSS) was investigated on a setup, which designed to thermally simulate the continuous casting process. The results showed that the macrostructure of the samples all exhibited chill zone, columnar zone and equiaxed zone. The distance from chill zone to position of columnar to equiaxed transition (CET) moved from 51.0 mm to 39.8 mm with an decrease of superheat from 70 °C to 10 °C, and that the grains in the chill zone tended to be finer. In equiaxed zone, the fme and uniform grains were observed when superheat higher than 40 °C; while, coarse grains were found in samples poured at low superheat. Generally, the volume fraction of ferrite increased along the dendritic growth direction, and stabilized in equiaxed zone. The high superheat decreased the volume fraction of ferrite in equiaxed zone, while it had indistinctive influence on chill zone and columnar zone.IntroductionDuplex stainless steel with approximately equal volume of ferrite and austenite, offering an attractive combination of corrosion resistance and mechanical properties. [ l]. The production of DSS, worldwide application in structural engineering[2] and petrochemical industry[3], have increase by more than 100% in the latest decade[4]. But due to the sharp prices increase of nickel and chromium, lean duplex stainless steels which have lower contents of alloy elements were developed. They perform well in both mechanical and corrosion resistance[S, 6] and even have TRlP(Transformation Induced Plasticity) effect[?]. Nonetheless , the mechanical properties of DSS was affected greatly by the solidification structure, such as columnar to equiaxed transition (CET), grain size and phase content[8]. So, the solidification behavior of stainless steel was investigated widely"

Jan 1, 2014

By Stephen C. Britten

An in-situ amperometric slag sensor for measuring the concentration of easily dissociable oxides in slags at temperatures between 1200-1600°C is being developed. The sensor provides the same information as potentiometric sensors while also providing data on the concentration of the transition metal species and the diffision kinetics within the slag. The electrochemical technique utilized in the sensor is similar to methods utilized in aqueous voltammetry.

Jan 1, 1998

By Chang Wei, Zhigan Deng, Yizhao WANG, Cunxiong Li, Gang Fan, Xingbin Li

During the process of hematite precipitation, the transformation of Na jarosite convert into hematite has been studied in a batch reactor at different temperatures, ranging from 170°C to 200°C with 3h of the retention time in the presence of 30g/L Fe ( ) and 4g/L Na+. The composition of precipitation was seriously depended on the temperature, at 170°C hematite and sodium jarosite are the reaction products of iron precipitate, with an increasing in reaction temperature the sodium, sulfur content in precipitated decreased and sulfur mainly exist in forms of SO4 2-, and when temperature over 200°C hematite was the only phase in product. An increasing temperature was not only beneficial to iron precipitation, also conducive to jarosite conversion to form high quality hematite precipitate.

Jan 1, 2016

By A. De, J. S. Zuback, T. Mukherjee, T. DebRoy

For successful commercial applications of additive manufacturing, metallic parts need to be defect free, structurally sound and reliable. However, additively manufactured metallic parts are susceptible to distortion, lack of fusion defects and compositional changes. Methods to measure susceptibilities of various alloys to these defects are needed but not currently available. Here we show that the necessary theories can be developed based on a well-tested numerical heat transfer and fluid flow model and decades of research in the field of welding. The proposed theories are validated with experimental results reported in the literature.

Jan 1, 2016

By Corby G. Anderson

For over a century, the Sunshine Mine in Idaho has been a major producer of silver. An estimated 335,000,000 troy ounces of silver has been mined. This has established the Sunshine Mine as the largest single source of silver in the world. Because the dominant silver containing mineral is tetrahedrite, a copper and antimony sulfide, normal metallurgical treatments to recover the precious metal are not practical. Thus, over the course of the company's history, novel, hydrometallurgical technologies have been developed on-site to handle complex, precious metal containing materials. Recently, the use of Sunshine technology has been extended to the recycle of secondary materials. As well, the use of Sunshine technology by other organizations for treatment of both primary and secondary feedstocks containing precious and base metals is an area of growing interest. This paper will provide an overview of Sunshine hydrometallurgical technologies including the applicability of Sunshine technology to the recycling of precious and base metals.

Jan 1, 1995