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By Zhihe Dou, Zimu Zhang, Guozhi Lv, Yan Liu, Xiaoli Jiang

"Cyclic heat stewed slag washing water carries high content of alkali and calcium and may cause serious tube scaling and impose an adverse impact on normal production. This study proposes a solution to utilize washing water by absorbing and mineralizing CO2, potentially restraining scaling and being able to create calcium carbonate powders. Effects of water flux on water quality, utilization ratio of CO2 and yield of calcium carbonate powder have been investigated; meanwhile, features of calcium carbonate powder are also represented. On the other hand, effects of factors such as as injection flux, pressure of CO2 on utilization ratio of CO2, morphology and purity of calcium carbonate are also investigated. The results show unambiguously that after soften injection of CO2, calcium ions were removed effectively via precipitation, alleviating the scaling problem. High purity yet fine carbonate powder could be achieved.IntroductionNowadays, 0.34 tons of blast furnace slags will be produced when producing 1 ton of pig iron; ensuing that, 0.12 tons of steel slag will be generated with 1 ton steel production while 1.57 billion tons of steel output all over the world in the year of 2012. It is therefore a critical issue to realize zero discharge of steel slags to achieve sustainable development and cyclic economy of iron and steel industry. In recent years, research institute of MCC and China JINGYE engineering company developed a heat stewed steel slag self-decomposition technology GENERATION III to solve the problem of instability of steel slags and realize the zero discharge. However, the problem of circulation line scaling which may cause the clogging, even exploding, need to be solved. The principles of the technology are: directly spraying water to the high temperature steel slag when it is poured into the hot closed pot, realizing the selfdecomposition via utilizing the waste heat of steel slag. The washing water is recycled to achieve a cyclic utilization. The process is shown in Figure 1."

Jan 1, 2014

By Donghai Li, Cheng Pan, Pan Chen, Xuewei Lv, Mei Liu

"Chromite concentrate after beneficiation can not be directly used in the electric furnace. Therefore sintering is one of the effective way to agglomeration, by which the chromite concentrate can be utilized and the power cost of ferrochrome smelting can be reduced. The properties of raw materials and the sintering process of chromite concentrate were studied in this work. The results showed that chromite concentrate used can hardly granulated alone, while chlorite addition can improve the effect of granulation. Moisture plays an important role in sintering process. The granulation effect is optimal when the amount of water addition is 12%. Strength and abrasion index are the evaluation indexes of sinter quality. It was found that the strength of sinter increased with coke dosage increasing to 12%, and then decreased when it continuously increased. Opposite regularities were found for the abrasion index of the sinter.1 IntroductionChromium is a very important metal element which is mostly used in the production of stainless steel. In the earth, it is always formed compound with iron as ferrochromium spinel (FeO.Cr203), and its mineralogical name is chromite.[1] Currently, the global production of chrome ore is about 20 million tonnage every year , in which fine ore (less than 8 mm) accounted for about 80% [2] Although the price of the fine ore is cheaper than the lump one, too much fines will lead to the poor permeability and causes increased electricity consumption while producing ferrochrome. Therefore, the agglomeration process of chrome ore is one of the effective measures to increase the usage ratio of fine ore."

Jan 1, 2013

By G. Scavino

A 0.5 wt.% C, 22 wt.% Mn austenitic steel, recently proposed for fabricating automotive body structures by cold sheet forming, due to favorable overall strength and ductility, exhibits plastic localizations during uniaxial tensile tests, whereas no localization happens during biaxial Erichsen cupping tests. Full-thickness tensile and Erichsen specimens, cut from as-produced sheets, were polished and tested at different strain rates. During the tensile tests, the plastic localization phenomena consist first of macroscopic deformation bands traveling along the tensile axis, and then of series of stationary deformation bands, each adjacent to the preceding ones; both types of bands involve the full specimen width and yield macroscopically observable surface relief. No comparable surface relief was observed during the standard Erichsen tests. The stress state being known to influence plastic localization phenomena, reduced-width Erichsen tests were performed with 10 to 30 mm width polished specimens, in order to explore the transition from biaxial to uniaxial loading.

Jan 1, 2009

By C. D. Chapman

Current regulations regarding the landfill disposal of asbestos containing wastes are inadequate to ensure there are no ground water or airborne emissions. Accordingly, there is growing recognition that asbestos wastes can only be safely disposed of by using techniques that destroy the hazardous fibres. An innovative high-temperature plasma arc technology (The MAGRAM Process) is being developed for the recovery of magnesium metal from asbestos together with supplementary magnesia containing feedstock. The furnace will operate in. open bath mode with aluminium and/or ferrosilicon being employed as reductant. An important advantage of the process is that magnesium vapour within the furnace will be generated close to atmospheric pressure rather than at reduced pressure under which existing processes operate. Thermodynamic modelling work has been undertaken to define the range of slag composition and furnace temperature under which magnesium production at atmospheric pressure is feasible. The effect of slag chemistry, reductant addition, and temperature on product quality and yield have also been investigated and key aspects have been tested on bench scale. A 300 kW pilot plasma furnace unit has been employed for the treatment of calcined asbestos wastes. Aspects of design and operation of the unit are detailed. Acknowledgement: This work is substantially financially supported by the European Communities under the Industrial and Materials Technologies (Brite EuRam H) Research and Development programme.

Jan 1, 1995

By Anja Pfennig, Thomas Böllinghaus, Marcus Wolf

During CCS components are exposed to a corrosive environment and mechanical stress which results in corrosion fatigue and is inevitably followed by the lifetime reduction of these components. The lifetime reduction of the cyclically loaded high alloyed stainless injectionpipe steel AISI 420C (X46Cr13, 1.4034) constantly exposed to highly corrosive CO2- saturated hot thermal water is demonstrated in in-situ-laboratory experiments (T = 60 °C, brine: Stuttgart Aquifer, flow rate: 30 l/h, CO2) in an environment similar to the on-shore CCS-site in the Northern German Bassin. In-situ tension-compression experiments were established simultaneously along with electrochemical measurements using a newly designed corrosion chamber in a resonant testing machine at a frequency as low as 30 – 40 Hz. In addition technical CO2 was introduced into the closed system at a rate close to 9 L/h. S-N plots, micrographic analysis and surface analysis of the fracture surface are demonstrated. X46Cr13 (surface roughness Rz = 4) reached the maximum number of cycles (12.5 x 106) at stress amplitude of 173 MPa producing a low scatter range of 1:3.5. Hydroxide and siderite layers were found on pits and crack surfaces. No typical fatigue limit exists. Pit corrosion prior to crack initiation may be identified as failure cause.

Jan 1, 2016

By Nicole de Jager, Michael J. Nicol

"In order to liberate gold from refractory gold ores and concentrates it is generally necessary to oxidise the surrounding sulphide minerals, typically pyrite and arsenopyrite. Traditional methods of oxidation include pressure leaching, roasting and bacterial oxidation. In recent years, bacterial and pressure oxidation have found increasing favour, although these methods are by no means completely satisfactory and each is subject to particular disadvantages.A novel process has been developed as an alternative to the traditional methods whereby electro-generated ferrate(VI) ions in alkaline solution are used to oxidise a pyrite concentrate. This process has been observed to proceed fairly rapidly and could prove to be a more economically viable process, as well as being more environmentally acceptable. As an added benefit, operating in an alkaline environment is advantageous for downstream cyanidation processes.Ferrate(VI) is a relatively unknown species, due mainly to its instability in acidic solutions. However, in alkaline solution it has been observed to be sufficiently stable for use as an oxidant when used under favourable conditions. Ferrate(VI) is most conveniently manufactured electrolytically via the dissolution of high-carbon anodes in strongly alkaline solutions. Some literature has been published on the electrolytic generation of ferrate(VI) and relatively high efficiencies have been observed by both the authors and other researchers.This study utilises both electrochemical techniques and leaching experiments to examine the kinetics of the oxidation of pyrite by ferrate(VI), which is produced electrolytically. Cyclic voltammetry, rotating disk voltammetry and potential step experiments have been used to investigate the kinetics and mechanism of the oxidation process."

Jan 1, 1997

By S. W. Marcuson

Smelting of nickel-copper sulfide ores at Vale Inco’s Sudbury operations commenced in 1888 and the first converting plant went into operation in 1892. As the demand for nickel grew, the smelting operations expanded and by the 1960’s the Copper Cliff Smelter featured the longest converter aisle in the world with space for nineteen Peirce-Smith converters. During this long period, different converting techniques and vessels were employed. The evolution of converting is reviewed with special emphasis on the modifications made to the Peirce-Smith vessel to accommodate the metallurgical and process needs of the changing times.

Jan 1, 2009

By Mark Cross, Diane McBride, Nick Croft

Extractive metallurgical processes rate amongst the most complex from the perspective of computational modeling. They typically involve multi-phase and multi-component fluid flow in very complex geometries, heat transfer driven by a number of interacting phenomena, solidliquid- gaseous phase change and mass transfer together with complex thermodynamics and associated chemical reactions. Beyond the model building itself, key challenges have always involved being able to identify the phenomena present together with interactions to characterize processes and experimental laboratory and plant data to parameterize the arising models – it is in this milieu, which require considerable process understanding and subtlety of thought, that David Robertson has made his contributions. We will review the achievements, over the last couple of decades, in computational modeling of extractive metallurgical processes and address some of the remaining challenges to enable simulation based process design, as we move through the 21st century.

Jan 1, 2014

By Peter R. Whiteley

"This paper discusses gaseous, solid and liquid injection technologies employed in the aluminium industry. The reasons for injection systems are presented, together with a description of the processes used. This includes a review of injection in crucibles, furnaces, launders, and into special purpose metal treatment boxes. The paper covers both the primary and secondary aluminium industries. IntroductionMany injection technologies are used in the aluminium industry and are in a rapid state of development. This paper provides a review of these systems and presents some thoughts on the possible future application of injection to further improve productivity and reduce losses associated with current applications.The Needs for InjectionThere are many issues facing the process metallurgist in the aluminium industry which call for the application of injection technologies now and in the future. In order to categorise these issues the industry may be broken into primary and secondary aluminium, although some of the concerns occur in both areas.The forementioned issues are variously concerned with improving metal quality, improving productivity, and reducing process problems.The use of injection techniques will be discussed under the heading of solid, gaseous and liquid injections, and the objectives and benefits of each covered briefly."

Jan 1, 1996

By Qingbo Yu, Qin Qin, Junxiang Liu

"Dry-granulation is a new process of molten blast furnace slag treatment and air is used as heat exchange medium. There are some shortages: poor effectiveness of granulation, high air-slag ratio and high energy consumption, which are the obstacles to popularize dry-granulation. Based on rotary cup atomization, the technique of recovering waste heat of molten blast furnace slag through waste heat boiler producing high pressure steam is exploited. The molten blast furnace slag is granulated to uniform small slag granules with high temperature, and slag granules pour into the waste heat boiler. It could produce steam, obtained in first row and second row tubes, when descending velocity of slag granules equaled 1.1mm/s and the Reynolds number equaled 7100. The application of the system for recovering waste heat from high temperature molten blast furnace slag has a significant meaning.IntroductionBlast furnace slag is one kind of solid waste in iron making process, which is discharged at the temperature range from 1723 to 1923K. In China, there was 0.162 billion tons of slag discharged in 2009, and the energy contained in the slag is equivalent to the energy in 9.4 million tons of coal equivalent. The sensible heat of molten slag is a very valuable waste heat source, so it is worthwhile to recover the sensible heat. At present, the molten slag is treated by a water quenching method. But in this process, the sensible heat is not recovered, moreover, an amount of water is consumed and harmful waste gas is discharged into the environment. Due to the considerations of energy conversation and environmental protection, the iron making industry pays close attention to dry-granulation, which is useful to obtain more benefits [1-4]. The sensible heat is recovered and an amount of water is saved by the method of dry-granulation. The amorphous content of slag granules obtained from dry-granulation is over 95% [5, 6], so the slag granules can be used as a perfect raw material for cement [7, 8].In the late 1970s, the Sumitomo Metal Industries, Ltd. and the Ishikawajima-Harima Heavy Industries, Ltd. jointly undertook the research of rotary drum granulation. This method has several disadvantages: the processing capacity and efficiency are low, and it is not adoptive to operate continuously in production [9]. From 1980, Nippon Steel, NKK, Kawasaki Steel, Kobe Steel, Sumitomo Metal Industries and Nisshin Steel were engaged on air granulation, and the experiments were operated for 6 years on the blast furnace in Nippon Steel. In the process of air granulation, there was great power consumption. The complexity of structure and the great floor space of the air granulation device caused high cost of investment. In 1986, Ukraine exploited a new method of heat recovery referring to the technology of Continuous Casting and Rolling [10]."

Jan 1, 2011

By Katsuyoshi Kondoh

The synthesis processing of Mg2Si or Mg2Si/MgO at lower temperature from the elemental magnesium alloy powder/chips and Si or SiO2 powder mixture was established via the repeated plastic working (RPW) based on Powder Metallurgy (P/M) process. RPW is much effective on the mechanical breakage of MgO surface films, which prevent from the solid-state reaction between Mg and Si powder. The solid-state synthesized Mg2Si particle of 200nm-2JIm is extremely fine, compared to that via the conventional casting process, causing the coarse one of 50-100um. This is because of not coarsening during the solid-state synthesis of Mg2Si. By using in-situ forming process of Mg2Si via RPW and pre-heating before hot working such as extrusion and forging, the magnesium composite material with Mg2Si or Mg2Si/MgO dispersions was developed in employing Si or SiO2 particles, respectively. For example, when employing AZ31 chips as raw materials of the matrix, it has low density of 1.85g/cm) and extremely superior mechanical properties, such as tensile strength over 350MPa with 5-10% elongation and Young's modulus of 47-50GPa, to the conventional Mg-Al-Zn alloys. The Mg composite alloy wires and pipes were produced via the hot extrusion process in the manufacturing plant, and also showed excellent mechanical properties.

Jan 1, 2003

By Katsuyoshi Kondoh

The synthesis processing of Mg2Si or Mg2SiIMgO at lower temperature from the elemental magnesium alloy powder/chips and Si or SiO2 powder mixture was established via the repeated plastic working (RPW) based on Powder Metallurgy (PIM) process. RPW is much effective on the mechanical breakage of MgO surface films, which prevent from the solid-state reaction between Mg and Si powder. The solid-state synthesized Mg2Si particle of 200nm-2um is extremely fine, compared to that via the conventional casting process, causing the coarse one of 50-100um. This is because of not coarsening during the solid-state synthesis of Mg2Si. By using in-situ fonning process of Mg2Si via RPW and pre-heating before hot working such as extrusion and forging, the magnesium composite material with Mg2Si or Mg2Si/MgO dispersions was developed in employing Si or SiO2 particles, respectively. For example, when employing AZ31 chips as raw materials of the matrix, it has low density of 1.85g/cm3 and extremely superior mechanical properties, such as tensile strength over 350MPa with 5-10% elongation and Young's modulus of 47-50GPa, to the conventional Mg-Al-Zn alloys. The Mg composite alloy wires and pipes were produced via the hot extrusion process in the manufacturing plant, and also showed excellent mechanical properties.

Jan 1, 2003

By Kimio Itagaki, Torn Matsumoto, Makoto Ohtsuka, Kentarou Harada

"The structure and hydrogen-absorption properties of LaNis thin films were investigated in the present study. LaNis thin films were prepared by a sputtering method with a radio-frequency power, Ws, of 50 -400 Wat substrate temperature, Ts, of323 -573 K. Nickel content of the films decreased with increasing Ws, however, there was no dependence on Ts. At low Ws and low Ts, amorphous films were deposited. In other conditions, the films were polycrystalline. The films prepared at high Ws and low Ts, or at low Ws and high Ts, exhibited only a (h k · 0) peak in the X-ray diffraction profiles. This indicates that the c-axis of crystalline films was oriented parallel to the substrate plane. At high Ws and high Ts, the films with columnar structure were obtained. Hydrogen-absorption capacity of the thin films increased with increasing Ws. The pressure plateau did not appear on the pressure-composition isotherms. The films deposited at high Ts represented a higher equilibrium pressure.IntroductionThin films of hydrogen storage alloys can be applied for an electrode of rechargeable battery or fuel cell, a filter for H1 purification and various kind of sensor. Some studies on the preparation of the thin films of LaNi5 intermetallic compound, which is a typical hydrogen storage material, have been done hitherto. Adachi et al. , 2) and Sakaguchi et al. 3) prepared amorphous and crystalline LaNi5 thin films using flash evaporation of alloy powders and measured the pressure-composition isotherm for the prepared film utilizing a quartz crystal mass monitoring (QC:MM) method. It was found that the prepared amorphous film absorbed hydrogen without disintegrating into the powders and the hydrogen-absorption capacity of the films increased with the degree of crystallinity. Sakai et al. 4) reported that the maximum hydrogen storage capacities of amorphous and crystalline LaNi5 thin films, fabricated by a RF sputtering method using combination targets, were about 40 mA h g-1 (LaNisHo.7) and 160 mA h g-1 (LaNi5H2.6), respectively. Uchida et al. 5, 6) prepared LaNi5 thin films using flash evaporation of alloy powders and measured volumetrically the pressure-composition isotherm for the prepared film. It was reported that the hydrogen-absorption capacity of the films changed by the annealing treatment."

Jan 1, 1998

By He De-wen

Based on the principle of life cycle assessment (LCA), municipal solid waste management (MSWM) was analyzed by life cycle inventory method. According to the system expansion and substitution method, the content and frame of life cycle analysis is summarized and applied to municipal solid waste. On the basic of feasibility research of life cycle analysis on MSWM, the paper put forwards complete and concrete ?three changes? measures under life cycle analysis on MSWM. Some aims of MSWM can be achieved under above conditions of LCA on MSWM: to improve the current system efficiency of MSWM; to enhance the serve quality of MSWM, to increase recycle garbage from MSW; to reduce waste amount and reach minimization and innocuity aim of MSWM; to help the departments of MSWM to get over all difficulties to realize their ideal goals.

Jan 1, 2009

By James C. Foley

In-situ characterizations of green state part density and sintering state have long been desired in the powder metal community. Recent advances in non-contact electromagnetic acoustic transducer (EMAT) technology have enabled in-situ monitoring of acoustic amplitude and velocity as sintering proceeds. Samples were made from elemental powders of Al (99.99%), Al (99.7%), Ag, (99.99%), Cu (99.99%) and Fe (99.9%). The powders were pressed in a uniaxial die and examined with acoustic waves for changes in velocity and amplitude during sintering. The changes in acoustic properties were correlated with mechanical properties. Evolution of a series of reverberating echoes during sintering is shown to provide information on the state of sintering, changes in sintering kinetics as well as having the potential for detection of interior flaws.

Jan 1, 2001

By O. Forsén

A new cell construction was designed for the study of the electrochemical behaviour of additives in conditions that simulate real copper, electrorefining. The behaviour of gelatine and thiourea was studied by applying different electrochemical methods, i.e. polarization resistance and voltametric measurements. In this study, individual galvanostatic electrolysis experiments were carried out for 120 hours. The organic additives were introduced to the electrolyte at certain intervals and their concentration was varied in the range &om zero to four ppm. An optical microscope was applied for the examination of copper cathode deposit microstructures. The results show that gelatine has a polarizing effect on the deposition potential of copper whereas even small amounts of thiourea depolarize the electrodeposition of copper. The maximum inhibitor efficiency of gelatine was obtained at a gelatine concentration of slightly lower than two ppm. When both gelatine and thiourea were present in the electrolyte, the depolarizing effect of thiourea exceeded completely the polarizing effect of gelatine. If chloride ions were added to gelatine and thiourea containing electrolyte, the electrochemical behaviour of the system was altered drastically. Chloride ions resulted in the prevailing of polarization effect caused by gelatine while the depolarizing effect of thiourea disappeared in this system. The polarizing effect of gelatine increased until chloride ion concentration of 30 ppm was reached. Also, the above electrochemical phenomena could be detected in the optical examination of copper deposit microstructure.

Jan 1, 1995

By Kouichi Nakano

Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

Jan 1, 2016

By A. J. Schindler, F-P Sawyer, T. Logan, M. L. Shutey-McCann, R. M. Perry

"Test work on biooxidation pretreatment of low-grade refractory gold ores has been ongoing at Newmont Gold Company since 1988, including laboratory testing and pilot biooxidation heaps (360 to 23,000 tonne). Metallurgical results of the biooxidation process utilizing Thiobacillus ferrooxidans (T. ferrooxiddans) have culminated in the design, construction, and operation of a biooxidation demonstration facility. The facility has processed 708,000 tonnes of refractory ore, using a batched process with separate pads for biooxidation and ammonium thiosulfate gold extraction. Siliceous sulfidic refractory (SSR) and carbonaceous sulfidic refractory (CSR) ores are treated separately during biooxidation pretreatment unit operation. Following biooxidation, the ores are neutralization with lime and placed on oxide leach pads or stacked on the ammonium thiosulfate leach pad. Gold is leached with either cyanide for SSR ores or ammonium thiosulfate for preg-robbing CSR ores.This paper will only address the biooxidation pretreatment process of the SSR and CSR ores.AcknowledgmentsThe authors appreciate the cooperation and approval of Newmont Gold Company Carlin Operations management for its support and permission to publish this paper. The paper draws on efforts and assistance of the following people and several others which are to many to list who participated over the past five years in bringing this project to its fruition: Dr. James A. Brierley, Chief Microbiologist, Newmont Metallurgical Services; Dr. Rong-Yu Wan, Metallurgical Manager, Newmont Metallurgical Services."

Jan 1, 1997

By Yasuhiko Ito

"This talk is concentrated on the topics of compound film formation on the substrate electrode by interdiffusion of substrate element and electrochemically deposited species and/or by direct electrochemical implantation of the component element of the film into the substrate. As a typical example, electrochemical implantation of nitrogen atom into Ti metal to form TiN surface film is described. Another example is the formation of various kinds of intermetallic compound films including Ni2Y, Ni2Dy and Pd3 Y by the electrochemical implantation of lanthanoid elements into transition metal electrodes. By combining these two methods, Sm-Fe-N ternary material film also could be formed. The principle and application of the ""electrochemical implantation"" are discussed in detail.IntroductionGenerally speaking, surface film formation by molten salt electrochemical process can be divided into the following three categories:(i) single element film formation on the electrode by electrodeposition,(ii) compound film formation on the electrode by electrocodepostion of more than two elements, and(iii) compound film formation on the substrate electrode by interdiffusion of substrate element and electrochemically deposited species and/or by direct electrochemical implantation of the component element of the film into the substrate.This talk is .concentrated on the topics of category (iii), especially on the electrochemical implantation. Typical example can be seen in the electrochemical implantation of nitrogen atom into Ti metal to form TiN surface film. Another example is the formation of various kinds of intermetallic compound films including Ni2 Y, Ni2Dy and Pd3 Y by the electrochemical implantation of lanthanoid elements into transition metal electrodes. By combining these two methods, Sm-Fe-N ternary material film also could be formed. The principle and application of the ""electrochemical implantation"" are discussed in detail with examples above as well as other experimental results also obtained very recently in the author's laboratory."

Jan 1, 2000

By Caisa Samuelsson, Taishi Matsushita, Hannes Holmgren, Sina Mostaghel

"Rönnskär Smelter of Boliden Mineral AB, Sweden, is a large end-processor of secondary raw materials and waste, including electronic scrap. Electronic scrap may introduce various impurities to the smelter's flow-sheet, among which alumina is a common and significant one. This article summarizes the results of an ongoing research at Luleä University of Technology, Sweden, to study the influences of alumina on different properties of slag from the zinc fuming process at Rönnskär smelter. A combination of different experimental techniques and thermodynamic calculations have been used to investigate properties such as density, surface tension, effective thermal diffusivity, viscosity, and melting/leaching behaviors. Results show that the addition of alumina to this slag increases the degree of polymerization of the melt, and physical properties vary correspondingly. Mineralogy of the semi-rapidly solidified samples is also changed due to alumina addition. A correlation between mineralogy and leaching behavior can be observed.IntroductionBoliden's Rönnskär Smelter is a base- and precious-metals producer located in north of Sweden. Its main products are copper, zinc clinker, lead, gold, and silver. Sulphuric acid, liquid sulphuric dioxide and iron sand (granulated slag) are some of its main by-products. In order to optimize the overall outcome of the process, different refining units are integrated in the smelter's flow-sheet (Figure 1). Copper concentrates and fluxing materials (mainly silica sand) are charged to the process. The produced matte is sent to the converter and the generated slag is charged to the fuming furnace, where it is treated by reducing gases to produce zinc clinker. The converter's slag is charged to the electric furnace, while the fumed slag is tapped into the settling furnace for further cleaning, where matte, slag and speiss (residual metals) are separated. The matte from the settling furnace is also sent to the converters; its speiss is sold to external customers; and its slag is water granulated and sold as construction material, which is known as iron sand."

Jan 1, 2012