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By Pertti Pekkala

Outokumpu has 25 years of experience in the SX area. The development of the solvent extraction plants responds to an ever increasing demand for lower operational costs wd for adaptability to process disturbances with minimized risks. In this paper the features of the VSF ("Vertical Smooth Flow") SX technology are described, such as the separated pumping and mixing, the homogenous gentle mixing, the droplet coalescence and the ultra pure settling. A major advantage of the mixing technology is the high stage efficiency of above 99 per cent. The connection between this and some features of the settler front section is clarified. The present design of VSF plants is based on experience of existing operations at, for example, Zaldivar, Radomiro, Morenci, Kokkola and Harjavalta. These production plants cover a unit capacity range of 60 to 3,600 m3/h expressed as a total flow. It is evident that there are no restrictive factors to increase the total flow up to 5,000-6,000 m3/h by introducing the VSF technology. The copper SX technology has a long history reflecting many individual features of the separate copper SX plants. Still it is necessary to verify all actual running parameters by pilot tests taking into account impurities, chemicals used etc. The design of SX plants is not only about the delivery of equipment but also a process concept, and it is best tailor-made and adapted to specific local requirements.

Jan 1, 1999

By M. Sakamoto, S. Karaswa, Y. Yoneoka, Y. Ohmizo

"The Annaka Refinery has been processing leach residue by Waelz process for 17 years. Recently, the quantity of the leach residue has increased due to a decline in the quality ~f zinc concentrate. Meanwhile, negative factors (e.g. deterioration of water balance due to improved electrolytic power consumption rate) have increased· in the processing of the leach residue.We have implemented various measures in responses to this situation, while striving to increase ·processing capacity and achieve stable operation. AS we have largely completed our assessment of the efficacy of these measures, we report on our recent process improvements.IntroductionWe have been treating leach residue by the Waelz kiln process since 1981. At that time, treatment of only 50,000 tons of leach residue per year was anticipated. However, subsequent process improvements have revised this figure up to 75,000 to 80,000 tons per year.However, today's increased Fe zinc concentrate grade has resulted in increased amounts of leach residue. In addition, improvements have reduced electrolytic power consumption rate of zinc electrolysis, limiting the amount of water that can be used in ·the zinc refining processes and for deaning leach residue. Consequently, we encounter an increasing number of problems and factors adversely affecting leach residue treatment, including increases in water-soluble Zn (WsZn) and. S (S04) in leach residue.To solve these problems, we have taken several measures to ensure long-term continuous operation and treatment of this increased · amount of leach residue. This paper discusses these measures."

Jan 1, 2000

By K. Murayama, M. Kawakami, T. Takenaka, S. Yokoyama

"Cokes play an important role of spacer in blast furnace. However, they degenerate during Boudouard reaction. Blast furnace cokes are reacted with pure C02 at I 072 to 1673 K. Reaction rate was obtained by the weight change of spherical specimen. The specimen after reaction was examined by microscopic observation. The reaction rate increased with temperature and was expressed by two Arrhenius type lines. The activation energy was 126 KJ/mol at higher temperature than 13 73 K and 202 KJ/mol at lower temperature range. At the higher temperature range, the reaction proceeded from the surface leaving unreacted core, whereas homogeneously whole inside at lower temperature. The porosity increased from the center to surface at higher temperature, whereas it was almost constant at lower temperature.IntroductionThe cokes have the function of fuel, reductant and spacer to keep gas and liquid flow in the blast furnace. Thus, the reaction mechanism of coke with several gas and the strength after the reaction should be important factor to control the blast furnace operation. The reaction mechanism of coke with C02 has been studied extensively. The rate equations were derived by Gadsby[ I], Ergun[2] and Turkdogan and Vinters[3]. They were compared and discussed by Kobayashi and Omori [ 4]. Effect of crystallization degree on the reaction rate was examined by Kashiwaya and Ishii[5]. Catalytic enhancement effect of ash componets have been clarified by Kashiwaya et. al. [6]. Although degradation of coke in blast furnace has been examined recently[7], however, the degradation of coke after the reaction with C02 has not been well clarified yet. In the present work, the metallurgical coke specimen was heated in N2 and C02 and the reaction mechanism and degradation behavior after the reaction was investigated."

Jan 1, 2000

By Cyro Takano

An alternative use for recycling of waste from bag house of iron ore sinter plant was tested by producing and evaluating" at laboratory scale, the self reducing cold bonded pellets. This waste was characterized and the self-reducing pellets were produced using anthracite coal fines as reductant and Portland cement or hydrated lime/Blast Furnace slag as binder. It was used the molar ratio of Fe2O3/C (fix) equal to 3. Evolution of cold strength with curing time, for different contents of binder, was evaluated. Cold strength of 200N/pellet was obtained, for sinter dust, after 10 days of curing. Suitable hot strength was also presented and no decrepitation and swelling were observed. Good fractional reduction was obtained at 950°C and 1137°C. These results show that this material may be used by the Self-Reducing Processes for hot metal production, as an alternative route for this dust destination.

Jan 1, 1996

By Yuanbo Zhang, Ruijun Wang, Qian Li, Zhao Jing, Guanghui Li, Zhengwei Yu, Chen Liu

The high content of sodium and potassium in sinter is harmful for blast furnace ironmaking. Reductive sintering technology can remove more alkali metals than conventional sintering process. In order to improve the removal ratios of Na and K, reductive sintering with both CO-containing flue gas circulation and carbon-bearing pellet was conducted in this study. Experimental results show that all indexes except the VSV and P were improved in reductive sintering with CO circulation. Flue gas circulation technique combined with carbon-bearing pellets were beneficial to reductive sintering, because it could maintain good sintering indexes and enhance the removal of Na, K. The best removal ratios of Na, K and reduction degree of iron oxides were 20.37%, 63.73% and 23.76%. In reductive finished sinter, silicate mineral becomes the important binder phase, and main iron mineral phases are wustite (FexO) and magnetite (Fe3O4).

Jan 1, 2016

By I. M. Richardson, M. Janssen, I. J. Bennett, V. A. Popovich

The most critical processing step during the manufacture of screen-printed crystalline solar cells is firing aluminium and silver contacts, which generates residual stresses and solar cell bowing. In this paper, an alternative Ag contact formation mechanism is proposed and aspects related to electrical contact properties, residual stresses and layer delamination are investigated. It is found that there are two main processing parameters affecting the uniformity and delamination of the Ag/Si interface, namely the peak firing temperature and the silicon surface roughness. Silicon surface polishing gives a better wetting of the silicon surface by the glass layer, resulting in a good contact and lower incidence of large voids, compared to the case of highly textured surfaces. The non-uniformity in the glass layer and large voids at the Ag/Si interface (in the case of a textured surface) are expected to have a negative effect on the mechanical strength of the solar cell.

Jan 1, 2015

By Takeshi Nagano

"Prior to discussing future trends of non-ferrous metals smelting and refining, the past developments are looked back. Social and economic environments in Japan over the past two decades are reviewed. Technological developments to comply with these environments are explained, taking for examples the cases of the Mitsubishi continuous smelting and converting process and Onahama's jumbo tank system for copper tankhouse. After considering the factors which will influence the improvements in non-ferrous processing, future trends are forecasted generally for copper, zinc, lead, aluminum and rare earth metals. Recent development works in Japan for the future are also introduced. In the discussed area, it appears that the emergence of new innovative processes would be difficult. The progress will be made rather toward the sophistication of the existing technologies, utilizing the advancement of the related technologies such as computers, electronics, etc. IntroductionThis paper discusses the future trends of non-ferrous metals smelting and refining on the occasion of the international symposium, ""The Metallurgical Processes for the Year 2000 and Beyond"".It is considered that the improvement of technology is greatly influenced by the social and economic environments which surround it. From this standpoint, review was made of Japanese case over the past two decades. Various new technologies were developed also in the non-ferrous metal world to comply with the requirements under the above environments. The examples are described in the cases of the Mitsubishi continuous smelting and converting process and Onahama's jumbo tank system for copper electro-refining.After foreseeing the major factors which will affect the technological developments in the future, the trends are forecasted for copper, zinc, lead, aluminum and rare earth metals generally. Some development works in Japan, which will give suggestions for future trends, are also introduced in some detail."

Jan 1, 1988

By Pierre-François Bareel

EU legislation imposes ambitious recycling targets for various consumer goods. End-of-Life Vehicles (ELVs), scrap iron and various proportions of Waste Electrical and Electronic Equipment (WEEE) are processed by shredding plants which recover most of the metals but produce Shredder Residues (SR) which are landfilled. They represent 20 to 25 wt.% of the shredder input. Energy issues for the coarse fraction of SR are now largely studied. However, below 2 mm, the calorific value falls off drastically. These Fine Shredder Residues (FSR) represent up to 55 wt.% of the total SR. To meet European objectives other alternatives to landfilling must be considered for the FSR. The present paper describes a study carried out to characterise the FSR and investigates ways to process them and produce marketable products. Applying Gy's theory, a sampling procedure was conducted over two years to statistically quantify the variability of the physical and chemical properties of FSR produced by a Belgian post-shredding treatment plant. Macroscopic characterisation has led to the identification of four material categories which could be separated according to their physical properties: ferrous metals (more or less oxidised), non-ferrous metals, an organic fraction (plastics, rubber, textiles, foams, wood) and a minerals fraction (glass, ceramic, concrete). The entrainment of small metallic particles within the pores of organic fragments will affect the quality of the separations.

Jan 1, 2006

By Guillermo Rios, Arbizum Cristina, Joa Viflals, Alba Sunyer

"Atlantic Copper is one of the largest copper producers in Europe. Its production facilities are located in Huelva (Spain) and account for the smelting of over one million tpy of concentrates to produce up to 260 ktpy cathodes and 900 ktpy of sulphuric acid. During copper concentrate smelting, the slag coming from the flash furnace and PS converters are treated in an electrical slag cleaning furnace. As a result of the treatment of the off gases from this furnace, approximately 2,000 tpy of a Zn-rich filter cake are produced and are sent to authorized waste managers. This paper describes the characterization of this material and the preliminary results of a new process to recover zinc as a pure zinc hydroxycarbonate while lead is collected as an indium-rich anglesite product. The behavior of impurities (Cd, As, Tl, Sn, Sb, Bi, Cu, Se, Te) in the leaching, solution purification and precipitation steps is also reported.IntroductionThe Atlantic Copper Metallurgical Complex in Huelva (Spain) was commissioned in 1970 with a capacity of 40,000 tpy of copper from concentrate. In 1975, the old blast furnaces were replaced by Outokumpu flash smelting furnace (FSF) technology, and the copper refinery capacity was increased to 108,000 tpy. Between 1994 and 1996, an expansion project was carried out to increase the copper from concentrate and cathodes to 250,000 tpy and 215,000 tpy, respectively. This expansion basically consisted of a new sulphuric acid plant, replacement of the anode furnaces by two 400 t units, redesign of the slag cleaning furnace (SCF), an increase in the electrolytic cells to 1,120 and implementation of ISA permanent cathode technology. Furthermore, a debottlenecking project has led to a capacity of 1,000,000 tpy of fresh concentrate since 1997. Meanwhile between 1995 and 1998, a cathode production rate of 260,000 tpy was reached as a result of a progressive increase in the current density in the refinery."

Jan 1, 2012

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 Kouji Mimura, Masahito Uchikoshi, Minoru Isshiki

"HfO2 is expected to be a gate dielectric used in ULSI alternatives to S1O2. Although the materials used in ULSI are required to be significantly pure, commercial Hf contains > 2 mass% Zr. It is important to establish a process for removing Zr from Hf. In the present study, anion-exchange separation using a multi-column method was employed. The separation tests were carried out at variety of temperatures and flow rates. The decrease in the flow rate of the mobile phase made the elution curves of both Hf(IV) and Zr(IV) broaden contrary to the case of Co(II), Cu(II), or Fe(III). This is caused by the difference in adsorption rate on the anion exchange resin. In addition, more than one column was connected in series in order to enhance the separation. As a result, the content of Zr(IV) was successfully reduced to 1/100 of that relative to the raw material.IntroductionHafnium is one of the most important materials in modem society. The main applications of Hf metal are as a control rod in a nuclear reactors because of its large neutron-capture cross-section and as an additive to various alloys because of its corrosion resistance [1]. In addition to those applications, attention has been recently paid to HfCh as a high-x"" dielectric used in ultra large scale integration, ULSI, as well as ZrCh, AI2O3 and La2C>3, which are expected to be alternatives to conventional S1O2 thin films [2].The materials used in ULSI are required to have a high purity in order to avoid unexpected errors due to impurities. Furthermore, high purity Hf is indispensable for investigating the intrinsic properties of Hf metal. Thus, it is significant to establish the purification process for Hf from both the industrial and academic perspectives."

Jan 1, 2012

By T. T. Chen

A mineralogical study of copper anodes and copper anode slimes was carried out to elucidate the silver phases present and the behaviour of silver during copper electrorefining. Most of the silver in the anodes is in metastable solid solution in the copper metal. As the copper dissolves, silver also dissolves, but is rapidly removed from solution by a variety of reactions. Some of the silver is precipitated as Ag by cuprous ions and some is precipitated as a complex CU-Ag-Pb-As-Se oxidate phase. Much of the silver, however, reacts with copper selenides to form, progressively, (CU,Ag) 2se, AgCuSe and Ag2se. The reaction commences at the periphery of the selenide grains and progresses inward; the result is commonly a silver-rich species on the outside of a silver-deficient core. Slimes collected periodically throughout the electrorefining cycle show a progressive silver enrichment of the selenides. Traces of Ag2Te also may be present, but the telluride seems to J:ie a rare constituent of most raw anode slimes.

Jan 1, 1989

By Kyle S. Brinkman, Kenneth L. Reifsnider, Fazle Rabbi

"Mixed ionic and electronic conducting (MIEC) ceramic membranes are HeteroFoaM's which play an essential role in a number of energy conversion related systems including the solid oxide fuel cell (SOFC), oxygen separation and permeation membranes, partial oxidization membrane reactors for natural gas processing, and high temperature electrolysis cells. Dual phase oxygen membranes consisting of an ionic conducting phase Ceo.sGdo.z02 (CGO) and an electronic conductive phase C0Fe204 (CFO) were fabricated and characterized by structural (XRD), microstructural (SEM-EDS) and broadband dielectric measurement techniques. In-situ measurements of the dielectric properties of working oxygen separation membranes are presented which indicate that the material's dielectric behavior can be an indicator for MIECperformance.IntroductionCeramic membranes which transport oxygen ions play an essential role in a number of energy conversion related systems including the solid oxide fuel cell (SOFC) [l ], oxygen separation and permeation membranes in the commercial and nuclear arena [2, 3], partial oxidization membrane reactors for natural gas processing [4], and high temperature electrolysis cells [5]. For the electrolyte functions, the membranes must transport oxygen ions only. On the other hand, permeation membranes, typically used in combustion devices to support oxy-fuel combustion or for partial oxidation reactions involving the production of synthesis gases, require mixed oxygen ion and electronic conduction (MIEC). Traditionally the tailoring of the ratio of ionic conductivity to the materials electronic conductivity, measured as the transference number, has been accomplished by the introduction of aliovalent doping elements creating point defects in the material facilitating the diffusion of charged species. However, several decades of research have not yet produced single phase materials which possess the concomitant ionic and electronic conductivity required for use in membrane separation applications. It is clear that novel ""dual phase"" heterogeneous materials will be required and that the surface reactions of these materials will be of particular importance as the industry moves toward thin films membranes [6]."

Jan 1, 2013

By Nolberto Moreno Borjas

This paper outlines the detrimental impact that unblended ore can have on the Ni and Co recoveries and the ore slurry density with real data from the Caron low-pressure ammonia leaching process for the Punta Gorda ore. The author briefly discusses the reason for the decrease in slurry density that the process experiences. The lower metal recoveries in the process that are caused by the unblended ore chemical characteristics and variations are shown with a data base statistical analysis drawn from the results obtained from a pilot test, designed with different ore bypassed from the normal process flow and a similar ore from a similar metallurgical treatment. Keywords: Ni-Co Laterite, Caron Process, Ore Blending, Slurry Density, Metal Recovery

Jan 1, 2004

By J. P. Evans

The modem 'copper smelter today utilizes tonnage oxygen for smelting concentrates. ,generating a high strength S02 off-gas leaving the smelter vessel. This gas stream. which also contains any unreacted oxygen, plus CO2; N2 and H20. also carries with it the volatilized portion of heavy metals in the feed, plus partly oxidized sulfide concentrates, The time/temperature history and subsequent treatment of this off-gas stream emerging from the smelting furnace exit up to the acid plant can influence the partitioning and segregation of heavy metals, in the off-gas circuit. Depending on this history. the type and characteristics of the chemical and physical reactions which occur in the gas handling system 'can be influenced. This fact can also be used as a tool to adjust the separation of copper from heavy metals. In this paper, the impact of different time/temperature histories of the gas, due to different furnace geometries and design. on the subsequent formation and characteristics of the smelter dust is examined. Based on the available data. several case histories drawn from examples using both bath and flash smelting technologies are analyzed from this perspective.

Jan 1, 1992

By Paul E. Queneau

The QS (Queneau-Schuhmann) copper converter is a gently sloped, stepped, horizontal kiln-type tilting reactor in which desired bath oxygen activity, compositional and temperature gradients are created by countercurrent flow of matte and slag phases through a series of controlled bubble plume, mixer-settler configurations. Flow of gas and slag is normally concurrent. Copper sulfide concentrates are top-fed, employing oxygen flash burners. Oxygen and oxygen-carbonaceous fuel mixtures are bottom-blown into the smelting bath through judiciously located, independently regulated submerged injectors. Composition and mass flow rates of injector inputs are controlled to produce bubble plumes of desired character, without jetting through and out of the bath. The mixer-settler pattern can be reinforced if desired by employment of suspended shallow baffles. State-of-the-art instrumentation provides timely information required to govern key process variables. The outstanding capabilities of the QS converter for coppermaking have now been indicated by the current success of industrial QSL (Queneau-Schuhmann-Lurgi) leadmaking reactors. Modified converter designs are employed for leadmaking, nickelmaking and steelmaking.

Jan 1, 1993

By Florian Kongoli

Non-ferrous smelting slags .can contain magnesia, which substantially increases the liquidus temperature. One option to counter this increase is to flux with calcia. In this work, experimental liquidus measurements including new measurements on industrial slags have been compared with a FACT-based thermodynamic model, which predicts the liquidus surface of multi-component iron silicate smelting slags containing both magnesia and calcia. The predictions, which agree well with experimental results, are summarized in both isothermal and non-isothermal diagrams to give a quantitative description of the liquidus surface.

Jan 1, 1998

By H. J. Roorda

With an increasing need to obtain metals by processing complex fine intergrown ores, the use of electron-optical techniques will become more important as a tool for mineralogical studies. Electron images enable a higher spacial resolution than can be obtained by optical microscopy and thus provide a powerful and necessary aid for the examination of small grains and finely locked particles. In this paper the mineralogy of Meggen ore was investigated. Both light-optical and electron-optical techniques were used to evaluate the mill feed and products of the concentrator. Detailed examination by reflected-light microscopy to assess the comportment of galena in the complex pyritic ore was inconclusive in establishing the cause for low lead recovery of only forty percent of the ore's lead content. Electron microprobe analyses indicated that the majority of the lead lost to the tailings was accounted for by extreme fine (often smaller than one micron) and complex intergrowths of galena in pyrite. The remainder was lost as fine free galena grains.

Jan 1, 1987

By R. Nilsson

In the present work the sulphide capacities of Ca0-Mn0-Si0, ternary slags have been measured in the temperature range 1798 - 1873 K by equilibrating the slag with a gas-mixture containing CO, CO,, SO, and Ar. The results are compared with the data reported in literature. A theoretical model has been developed in the present work where the sulphide capacity is expressed as a function of the slag composition and temperature. The model enables the estimation of sulphide capacities of complex slags with a knowledge of the capacities of simpler systems.

Jan 1, 1994

By Norihiko Fukatsu, Takashi Iwamoto, Noriaki Kurita, Koji Katahira, Kunihiro Koide, Teruo Ohashi

"The galvanic cell-type hydrogen sensor employing CaZro.9Ino.t03-a. as the solid electrolyte was designed for the measurement of hydrogen activities in molten copper under industrial .conditions. The sensor probe consists of the cap-shaped solid electrolyte with porous platinum electrode on the inside and alumina refractory tube. The gas mixture of the composition 4%H2-0.5%02-Ar was made to flow on the inside electrode. The hydrogen sensor probe was inserted directly into molten copper and the melt was used as the outer electrode. The effect of oxygen activity gradient to EMF was eliminated theoretically by measuring the oxygen activity in the melt simultaneously with an oxygen sensor. The high stability of output and excellent response to the change of hydrogen activity were obtained over the wide range of industrial copper melting conditions.IntroductionIn the metal casting process, hydrogen easily dissolves in molten metals from water vapor in the surrounding atmosphere. Owing to the large difference in hydrogen solubility between liquid and solid metal, dissolved hydrogen becomes a cause of the defects of blowholes in castings or ingots. It is necessary to control the hydrogen content in the molten metals [l]. Using proton-conducting ceramics as a solid electrolyte, high temperature-type hydrogen sensor can be constructed [2]. SrCe03- and BaCe03-based perovskite-type oxides exhibit appreciable proton conduction under hydrogen containing atmosphere at high temperature [3-5]. A hydrogen sensor for molten aluminum using CaZro.91no.103-a. has been developed and widely used in the ·process control in the aluminum melting industry [6,7]. The same type of hydrogen sensor has also been expected in the copper melting industry. .. However, CaZro.91no.103-a shows ·not only proton but also oxide ion conduction in the high temperature and at low oxygen activies like the copper melting· conditions. Then we studied the oxide ion conduction in CaZro.91no.103-a. iit · detail [8]. From the consideration on the EMF of the galvanic cell employing this material as electrolyte, it was shown that the unknown hydrogen activity may be precisely determined from cell potential which is corrected for the effect of oxygen potential gradient And the hydrogen sensor based in this principle was constructed and tested in laboratory-scale [9,10]. We repeated the similar tests in factory-scale and developed the sensor system for practical uses [11, 12]. In this report, the structure and system of the hydrogen sensor for molten copper will be introduced first. The reliability of the sensor will then be demonstrated from the results of experiments for sensor probes carried out in TYK's laboratory."

Jan 1, 2000