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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 John O. Marsden

The past fifteen years have seen a number of important developments in copper hydrometallurgy, including the commercial application of biological heap leaching of secondary (chalcocite-dominant) copper ores, the commercial demonstration of chalcopyrite concentrate leaching technology using pressure leaching and biological processes, and the application of novel configurations of solution extraction circuits. Significant emphasis is now being placed on the development of effective stockpile leaching practices for primary ores (chalcopyrite and bornite-dominant mineralization). Some of these developments have been highly successful, and will pave the way for further development and commercialization. Others have been less successful. These developments are reviewed in the context of the metal price cycle and trends for the future are identified.

Jan 1, 2006

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21" century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, arc being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21 st century arc copper producers. The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers arc looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery. Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology. New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources. It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By A. V. Tarasov

The proposed process is based on creating a controlled frothed layer of molten slag, in which fine particles of carbonaceous reductant and raw material to be processed are mixed with emulsified iron. Frothing of the slag layer without external blowing occurs as a result of intensive evolution of gaseous reduction products. The froth reaction process is maintained due to the heat of an electric arc in the slag layer. When the metal bath is heated by the arc to 1400- 1 500°C, the low temperature of the slag surface of about 1200-1 300°C is maintained due to low thermal conductivity of slag froth preventing heat loss. In order to maintain the required slag froth level and control the process temperature, air tuyeres are installed above the slag bath; blowing air serves also for oxidation of zinc in fumes and for its transportation. High adsorption and thermal insulating properties of slag froth ensure virtually complete elimination of dust and mist entrainment along with low heat losses. The main macrokinetic regularities of the carbon thermal reduction of zinc-containing slag melts have been studied under frothing conditions. The mechanism of formation of gas-slag emulsion has been identified under the conditions of reaction [C]+[O]=CO occurring locally at the slag-metal interface. It has been demonstrated that under the froth reduction conditions the zinc removal rate from the melt increases on the average by 3 to 5 times. Based on the physical and chemical data obtained, basic principles of the dezincing technology have been developed for different intermediate oxide iron-containing products produced in the process of ferrous and non-ferrous metals production.

Jan 1, 2002

By Shaohua Ju, Jin-hui Peng, Ya-jian Wang, Shuai-dan Lu, Li-bo Zhang, Lei Guo

"The granulation of a red mud is of great importance for recycling this material as an adsorbent for waste water or gas. A new granulating process was developed and its effect was evaluated. To reduce the cost of the granulation process, the wet filter cake (containing 25% water) was directly mixed with different cement contents (4%, 6%, 8% and 10% based on wet material). The mixtures were placed in a moist environment for 4 days, and then were washed with deionized water until the pH values of leachants were lower than 9.0. The efflorescence ratio, surface area and particle size of the aged mixture were determined, respectively, by bottle shaking experiments, N2 adsorption and screening. The results showed that the best addition of cement is 2%, and this yielded granulated material with a particle size of less than 2 mm, an efflorescence ratio of 4.83% and a specific surface area of 17.42 m2/g.IntroductionRed mud is a residue of the aluminium industry that is produced during the alkaline extraction of alumina from bauxite by the Bayer process. For every ton of alumina that is produced, the amount of red mud generated can vary from 0.3 to 2.5 tons, depending on the characteristics of the bauxite. In its typical form, red mud is brick red in colour, caustic, about three times as dense as water and, when un-neutralised, has a high pH, typically around pH 13 [1]. It is primarily composed of iron oxide, silica and alumina, along with traces of heavy metals. Red mud particles are quite small; typically 99% will pass through a 0.6 mm sieve and 87% through a 0.038 mm sieve [2],"

Jan 1, 2012

By Lichao Ding, Chunhua Liu, Yunnen Chen

"In this paper the simulated acid magenta dye discoloring the reaction process was researched. The results showed that it attained highest decolorization efficiency for acidic magenta simulation dye wastewater when pH 9 and reaction time 10 min. With the initial dye wastewater concentration increased, the decolored rate decreased. The decolored rate in general kept a tendency to increase with the temperature increased. Kinetics researches showed that when pH 9, reaction temperature 20 and 35 ?, the decoloring reaction process for the dyes accorded with the First-order dynamic equation. The decoloring reaction rate constant was influenced by initial concentration of dye wastewater and temperature.1. IntroductionIn China, textile printing and dyeing industry is one of industrial departments which using more water and discharging more wastewater. There is about 7 billion tons of waste water discharge each year, of which 80% from the process of printing and dyeing. Being complex ingredients, high chroma, more toxic substances and severe environment pollution, the treatment of printing and dyeing wastewater becomes problem urgent to be resolved. The traditional treatment methods such as adsorption [1], coagulation [2], biochemical method [3,4], which has advantages of simple equipment, simple operation and mature process, but they can cause waste accumulation and secondary pollution [5,6].Magenta is a kind of organic compounds, which classified into acid and alkaline magenta. Considering the advantages of simple operation, low cost, simple experiment equipment and friendly to environment, acid magenta dyes wastewater was chose as object in this paper. Some parameters such as pH, contact time, temperature and the initial concentration on of simulative acid magenta dyes wastewater were studied."

Jan 1, 2012

By Susumu Nagae, Hajime Ikeda

Recently, a number of mine development projects have been setback by social, economic and, environmental circumstances that had not been seen before. Many of these problems do not always originate from direct mine pollution. Typical examples of these are· conflicts between the exploration company and the local residents, sudden objections just before the development is to begin, and unexpected tightening of environmental regulations. The common background to these problems is expanding global environmental awareness. This includes complex factors ·such as the expansion of exploration to remote regions, the brisk activities of environmental NGOs, the increase of international environmental laws and, governmental policy changes. Today, the range of issues concerning mine development is widening significantly. The participation of local residents arid NGOs in the development planning, together with the company and government, has become essential for smoothly carrying out mine projects and making them more beneficial for stakeholders. Introduction The common image of the environmental problem with respect to mining is direct mine pollution, such as the collapse of tailings dams, pollution from refineries, and acid mine drainage. All over the world, the mining industry has made large investments in capital and technology to solve and prevent mine pollution, and these efforts have been making steady achievements. However in recent years, new cypes of environmental problems which are not originating directly from mine pollution are emerging frequently. Most of the problems are concentrated at the exploration stage to early stage of development, which have less impact on the environment. In the worst case, mining project may be forced to cancel and could cause serious damage to the industry because they could not collect their investment. I would like to take a general view of the examples of new types of trouble, their characters, background, and strategies against these problems.

Jan 1, 2000

By Gaifeng Xue, Lei Zhang, Xia Liu, Lina Wang, Pu Liu, Benquan Fu

"Experiments were conducted to investigate the behavior of the integrated process with a three-dimensional electrode reactor combined with Fenton process for coking wastewater treatment. Effects of initial pH value, reaction time, H20 2 dosage, Fe2+ dosage on Total organic carbon (f OC) removal rate were investigated. The kinetics of degradation of TOC from coking wastewater by three-dimensional fluid bed electrode reactor combined with Fenton process was also studied. Experimental results shows that three-dimensional fluid bed electrode reactor combined with Fenton process had better synergic effect, average 17.4% TOC removal rate was improved within an hour. It was found that TOC degradation in coking wastewater followed a pseudo-first-order reaction kinetic model. The optimum degradation efficiencies of TOC were up to 60% as pH3.4, 3.5 mM ofFe2+ andl.2-1.8ml/L H20 2 in 90min reaction period. Furthermore, the integrated process showed a rapid reaction performance at a low temperature within a short reaction time and remained high efficiencies for TOC removal. Overall, the integrated process was proved feasible for coking wastewater treatment in practical applications.IntroductionCoking wastewater is generated from coal coking, coal gas purification, and by-product recovery processes of coking, which is composed of phenolic compounds, heterocyclic compounds, polycyclic aromatic hydrocarbons, ammonia, cyanide, polycyclic nitrogen-containing aromatics, acyclic compounds, etc. Most of these constituents are refractory, poor biodegradability, toxic and carcinogenic['-31. Currently, coking wastewater is usually treated by different forms of A/O biological nitrogen removal process as the primary treatment process, but the aforementioned processes are not efficient enough to meet the requirements from the National Discharge Standard in China (GB13456-1992). According to the continuous requirement on improving environmental protection for coking industry (revised 2008), increasing wastewater utilization ratio and reducing discharge of effluent in the coke industry has to be implemented for cleaner production and sustainable development. Therefore, advanced technologies need to be developed to treat coking wastewater and reutilize the product as industrial cooling water, which would be one of the best choices to achieve zero discharge of wastewater and reduce water consumption per ton of steel [4-51 . In this study, three-dimensional fluidized bed electrode reactor combined with Fenton process was adopted to advanced treatment of coking wastewater, and the effects of operating conditions, including H2O 2 dosage, Fe2+ dosage, initial pH, and reaction time on TOC removal rate, were investigated. Meantime, study of kinetics of reaction was estimated."

Jan 1, 2013

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 Jiangtao Li, Zhongwei Zhao, Xingyu Chen, Xuheng Liu

In order to produce good quality ammonium paratungstate, Sn needs be removed efficiently from the tungstate processing solution. The nascent hydrous ferric oxide has excellent adsorption ability and is often used as an adsorbent to remove metal ions from aqueous solution. In this paper, nascent hydrous ferric oxide is used to remove Sn from tungstate solution. Through experimental, the effects of pH value, reagent amount of adsorbent, reaction temperature and reaction time on the Sn removal are investigated. The study shows that 98% of Sn can be removed effectively from sodium tungstate solution and only 2% of W is lost during process under the conditions of pH 9~12, reagent amount of Fe addition 40 times Sn amount, reaction time 30min and room temperature. As the Fe addition reaches 90 times of Sn concentration in the ammonium tungstate solution, 99% of Sn is removed and APT with zero level purity national standard is obtained.

Jan 1, 2014

By Samson Adeosun, Sanmbo Balogun, David Esezobor

"Iron and steel making processes give rise to large amounts of usable and unusable materials, the latter generally being termed wastes. It is sometimes difficult to distinguish between re-usable by-products and wastes which cannot be sold or land-filled. Much depends on circumstances such as the local market for the material. This can itself vary from time to time with by-products which cannot be used or sold becoming wastes and vice versa. This paper defines the concept of “waste-free technology”, discusses its development in the steel industry and highlights the benefits of the technology to the manufacturing sector and the environment. The paper also articulates how the “waste-free” technology could be applied in the proposed Ajaokuta integrated steel plant in Nigeria.IntroductionIn the past, nature was considered an inexhaustible store. Its resources were consequently exploited and waste products therefrom were discarded. Today, attitudes have not changed appreciably even as raw materials cost rise by the year to pose a series of socio-economic problems, which, among others, may include the rational and optimum utilization of resources, environmental protection and reduction of waste formation. Consequently, industrialists now face unexpected regulatory pressure in areas of pollution prevention, waste minimization and hazardous waste disposal.Iron and steel making processes give rise to significant amounts of usable and un-usable materials, the latter generally being termed waste. It is sometimes difficult to distinguish between re-usable by-products and wastes which cannot be sold or land-filled. Much depends on circumstances such as the local market for the material. This can itself vary from time to time with by-products which cannot be used or sold becoming wastes and vice versa. In this paper, the term waste refers to those materials that are either irrationally utilized or, land-filled and part of the byproducts that are not utilized. It includes that part of used materials which is not incorporated into the products manufactured during a process stage and which in contrast to reuseable materials, is considered not suitable for any further use, owing to technical or economic factors. In general, these materials are inorganic and parts of them are either utilized or passed to the other processes; the other part should be disposed of using well-established waste disposal practices to avoid any environmental threat.Thus, creative methods must be developed to modify the manufacturing processes to reduce emissions and process wastes by fully utilizing all resources. One method of eliminating the negative effect of waste formation is the use of purification and cleaning structures (pollution control system, PCS). These are, however, quite expensive."

Jan 1, 2008

By Afshin Sadri

Acousto Ultrasonic-Echo (AU-E) is a technique developed to provide accurate measurements of the refractory lining wear in operating smelters based on the principles of stress wave propagation. The objective of the system is to provide feedback for the continuous optimization of the overall smelter operation. In some cases, the AU-E refractory lining measurements have allowed clients to extend their smelter campaigns and operate safely for several years beyond their planned reline schedule. In other cases, AU-E results inform clients of serious issues within their furnace allowing them to shut down their smelters ahead of predicted failures and possible disasters. This paper presents the results of several smelter AU-E inspections of the hearth and sidewall. These case studies demonstrate how the AU-E results were used to positively affect the smelter operation.

By David Tisdale, Phillip Mackey, Nagendra Tripathi, Matthew Kreuh, Pascal Coursol

Xstrata Nickel’s Sudbury smelter operation is based on fluid bed roasting of Ni-Cu sulphide concentrate, followed by electric furnace reductive smelting and Peirce-Smith converting to produce a Bessemer matte for electro refining, along with sulphuric acid produced from smelter gas. While the site dates back to the 1930s, the present smelter configuration has been operational since 1978, and currently has a nominal capacity of about 67,000 tpy of contained nickel and is investigating options to expand in future up to 85,000 tpy. As part of a review of plant capacity options, a new metallurgical model of the plant was developed in order to examine a number of processing alternatives. Based on the METSIM™ platform, the present model includes the ability to examine the impact of a number of plant parameters on potential plant performance including; for example, the following: percent of sulphur elimination in roasting, matte grade, degree of matte metallization, temperature, coke requirements, sulphuric acid production, CO2 emissions and overall energy requirements. The process model also includes a number of special features adopted; for example, approaches to effectively model the complex Ni-Cu-Co-Fe-S-O matte system. This paper provides a description of the model and gives an overview of the results. As well as presenting the results of the present study, the applicability of this modeling approach to pyrometallurgical systems in general is also briefly discussed in the paper.

Jan 1, 2009

By Jan A. Aune

The paper describes a number of electric furnace equipment modules especially developed or modified for slag furnace applications. Both the resulting design concept for a modern electric sulfide smelter and some of the changes in traditional process-concepts made possible are outlined.

Jan 1, 1983

By Aiyuan Ma, Kun Yang, Weiheng Chen, Jinhui Peng, Shiwei Li, Feng Xie, Libo Zhang

In this thesis, a new process of recovering zinc sulfide ores was developed. The novel synthetic coordination leaching process mainly included two steps: microwave assisted phase reconstruction and compound coordination leaching. By applying various techniques, such as chemical composition analysis, X-ray diffractometry (XRD) and Raman spectroscopy, it could be concluded that sulfide phases would directly oxidized to zinc oxides under the 500 ºC microwave roasting and adding 30% Na2O2. What’s more, zinc leaching rate reached to 61.16% within 2 hours. Compared to the current technologies, this procedure had the advantage of avoiding SO2 emission, high leaching efficiency, simple process, manipulate easily, and low cost, which could be expected tremendous application potentials.

Jan 1, 2016

By C. J. Boreiko

Traditional patterns of lead and zinc utilization are being evaluated in accordance with new paradigms that seek to ensure the long-term compatibility of global industrial activity with precepts of sustainable development and sustainable consumption. As a consequence, both industry sectors are experiencing intense scrutiny from the international community, and numerous regulatory options are being considered that may impact upon international industry practice. This paper reviews the growing expectations being placed upon industry, and highlights some of the common regulatory concerns being expressed regarding both metals despite their differing toxicological profiles.

Jan 1, 2000

By Federica Paglietti

In this work is presented SEX (Structural & Elemental X-Ray Instrument), the first spectrometer completely portable which make non-destructive X-ray fluorescence and diffraction analysis, in contemporary and in real time. This instrument has been realized using miniaturized detectors, the same model installed on the mission Pathfinder NASA, and X-ray microtubes. SEX allows the chemical and mineplogical characterization of all kind of solid materials and allows to make chemical stratigraphy and liquids analysis.

Jan 1, 1998

By Joo Hyun Park, Kyu Yeol Ko

The viscosity of the CaO-SiO2-xMnO-yCaF2 slags (C/S=1.0; x=10, 40%; y=0 to 15%) was measured to clarify the effect of CaF2 on the viscous flow of molten slags at high temperatures. Furthermore, the Raman spectra of the quenched glass samples were quantitatively analyzed to investigate the structural role of CaF2 in a depolymerization of silicate networks. The critical temperature of the slags abruptly increased at 15%CaF2, which was confirmed to originate from a crystallization of cuspidine using XRD analysis. The viscosity of the slags continuously decreased by CaF2 addition in the 10%MnO system, whereas the viscosity of the 40%MnO system was not significantly affected by CaF2 addition. The effect of CaF2 on the viscosity of the slags was quantitatively analyzed using micro-Raman spectra of quenched glass samples accompanying with a concept of silicate polymerization index, Q3/Q2 ratio. A polymerization index continuously decreased with increasing content of CaF2 in the 10%MnO system, whereas it was not affected by CaF2 in the 40%MnO system. Consequently, the bulk thermophysical property of the CaO-SiO2-MnO-CaF2 slags was quantitatively correlated to the structural information.

Jan 1, 2014

By Xinghua He, Shujing Zhu

"Cycled fluidized bed ash (CFBA), a significant portion of fly ash produced from coal-fired power plants and rejected from the ash classifying process, has remained unused due to its high free CaO and S03 content. It is necessary to extend research on the method to reduce the expansion and improve the compressive strength by some effective chemical activator. This paper presents experimental results on the expansion by Le chaterlier tester and the compressive strength. Hydraulic ash-zeolite (HAZ) cementitious material was blended as the chemical activator to study the effects of the activator on the expansion and the compressive strength. The results show that HAZ can not only reduce the expansion, but also increase the prisms compressive strength. Scanning electron microscope observation and X-ray diffraction analysis indicate that the main hydrated products of the sample are calcium hydroxide, ettringite, zeolite and calcite, which can explain the results of the expansion and the strength tests.IntroductionNearly 80% of the electricity in China is produced by coal-fired plants, which results in the production of a large quantity of coal combustion residues, among which coal fly ash is the major component. Because of that the air-pollution becomes heavier as time going on. Cycle-fluidized-bed-combustion systems are retrofitted to meet air-emission standards mandated by China Clean Air Act. Cycle fluidized bed ash (CFBA) will present new challenges for coal-combustion byproduct management. The use of cycle-fluidized-bed ash as a cement replacement in concrete is the most attractive one because of its high volume utilization and widespread construction. However, the replacement of cement with cycle fluidized bed ash in Portland cement concrete usually increases the expansion and decreases the early strength of concrete. In many research of this field, most of them were focus on the activation of pozzolanic activity of CFBA and to make all kinds of blend cement. A number of studies had been carried out on the activation of CFBA using chemical activators. These studies involved using different activating methods including alkali activation and sulfate activation 11, 2]. The former involved the breaking down of the glass phases in an elevated alkaline environment to accelerate the reaction [3, 4]. The later is based on the ability of sulfates to react with aluminum oxide in the glass phase of CFBA to produce ettringite that contributes to the strength at early ages [5-7]. With respect to sulfate activation, the use of gypsum and sodium sulfate had been well studied [5-8]. HAZ is one of HAS sub-products which is a patentd chemical activator made by Wuhan University (ZL98113594.3). It had been used to activate CFBA to produce blend cement in many Chinese engineering projects and time has told us that it is a good activator."

Jan 1, 2012

By Giuseppe Granata

An innovative process using titanium tetrachloride (TiCl4) gas as reactant has shown successfully to obtain titanium through electro-winning of TiCl2 formed in-situ on titanium cathode. The process involves a continuous feed of TiCl4 gas reacting onto a titanium cathode immersed in a molten salt (NaCl-KCl), whereby in-situ formation of titanium dichloride (TiCl2) through a disproportion reaction. Simultaneously, the TiCl2, thus in-situ formed in the molten salt media, has been reacted into chlorine gas and titanium, the latest electrodeposited on the titanium cathode by electrowinning. The reaction kinetic of this innovative process was investigated in terms of TiCl2 in-situ formation rate and galvanostatic electrodeposition rate, where, in particular, the effect of operating variables such as TiCl4 partial pressure and flow rate, as well as temperature and galvanic potential applied was investigated.

Jan 1, 2014