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By Zbigniew Smieszek, Ryszard Chamer, Ryszard Prajsnar, Zygmunt Kurek

"Lead-containing wastes processed at the IMN’s Division in Legnica originate mainly from dry and wet dedusting installations of the technological lines for copper production. These are lead dusts and lead-zinc dusts characterised by the specific properties resulting from the chemical composition of the Polish copper concentrates. Besides lead, they contain many accompanying metals and impurities such as zinc, copper, sulfur, chlorine, potassium, sodium, and also bituminous substances. Processing of lead-containing dusts is conducted in the installations of rotary-rocking furnaces heated with gas-oxygen burners fitted with auxiliary systems for cleaning process gases and refining re-circulating dusts. The processing technology utilizes innovative process and technical solutions enabling disposal of lead-containing wastes from copper metallurgy and from non-ferrous metals industry according to the BAT recommendations and to the guidelines specified in integrated permission. In this paper, the main technological aspects of processing lead-containing dusts at the IMN’s Division in Legnica have been presented.IntroductionCrude lead is obtained in Polish lead metallurgy from various primary and secondary materials, such as Zn-Pb concentrates, lead-bearing dusts of copper metallurgy and battery scrap. In zinc smelter Miasteczko Slaskie S.A. crude lead is produced from sulfide and oxide Pb-Zn concentrates in ISP process. Orzel Bialy S.A. and Baterpol Ltd. produce crude lead in short rotary furnaces in the process of smelting products of mechanical battery scrap separation– desulfurised or not desulfurised paste and metallic fraction. KGHM Polska Miedz S.A. and IMN Divison in Legnica produce crude lead in rotary furnaces in the process of smelting of polymetallic dusts and slimes from copper production processes."

Jan 1, 2008

By M. I. Zinigrad

A model of an ideal associated solution is presented. This model takes into account the existence of complexes of various compositions, sizes and geometries and allows calculating thermodynamic properties and phase diagrams of binary alloys. The model has been used formerly to calculate thermodynamic parameters and the position of the liquidus line for binary eutectic systems and also those having a stable compound in the solid phase. In all the cases the model parameters were not adjusted rather estimated from melting temperatures of the components. The recent studies dealt with the influence of arbitrary-stoichiometry associates on the equilibrium thermodynamic properties of liquid alloys. The application of the model to eutectic systems and systems having an unlimited solubility in solid and liquid states close to liquidus has been considered. It was shown that if the difference in melting temperatures of the components was small, different types of fusibility diagrams were possible: eutectic diagrams, cigar-shaped diagrams or diagrams with upper or lower azeotropic points. Peritectic transformations could take place when the difference in melting temperatures of the components was large. The present work is devoted to calculation of phase diagrams and thermodynamic properties of binary systems on the basis of chrome.

Jan 1, 2006

By Johan Sundström

Anhydrous DyC13 was prepared by dehydration of DyCl3?6H20 in a fluidized bed using both batch- wise and continuous feeding. A gas mixture with varied composition of argon and HCl was used. The productivity was high, reaching values of 0.25 mol H20/m2-st during the reaction step 6- 1 and 0.062 mol H2O/m2.s during the reaction step 1-0. The product was free from hydrolytic compounds, such as DyOCI, if control of inlet gas composition versus temperature was achieved. From the results of various experiments, some relations between HCI-concentration and temperature in order to avoid hydrolysis have been deduced. The fluidization process efficiency decreases drastically after the dehydration has proceeded down to about 10 mol% of remaining water. Therefore, in a final treatment the last traces of water were removed by slowly purging gas through a packed bed. The water content could thereby be reduced to less than 1 mol%.

Jan 1, 1997

By S. F. Cheng

Among the many extraordinary features of the rare earths are their magnetic and magnetoelastic properties. The rare earths, e.g. Tb, Dy, Nd, Sm, are known worldwide for their large magnetocrystalline anisotropy and magnetization, which has led to the importance of magnetic rare earths as vital ingredients of modem permanent magnets. In this paper, we focus on the strain dependence of these giant effects which gives rise to huge magnetostrictions, magnetomechanical couplings, and ?E effects. Magnetostrictions greater than 10-3 have been measured at temperatures as high as 500 K. At low temperatures magnetostrictions reaches -1%. ?E effects - 10. No other solid state material has matched these values. A proper balance of magnetic anisotropy and magnetostriction, plus a proper choice of crystal axes lead to alloys which can switch large quantities of energy between the internal (magnetic) and external (mechanical) states with the application of small triggering magnetic fields. In addition to the traditional use of these materials in transduction, they are particularly valuable for smart systems where reliability and robustness are needed such as active structure stiffening and active vibration control.

Jan 1, 1997

"Silver is traditionally recovered in base metal smelters (lead and copper), or as a by-product of other precious metals (gold and/or PGM's). This paper presents the results of non-conventional techniques to recover silver from complex materials. The PLATSOL® process has been developed to recover, in one step and without the use of cyanide, base metals (copper, cobalt, nickel) and precious metals (gold, PGM's) from sulphide concentrates too low in grade to enter the mainstream extraction processes. Silver is only partially recovered in solution with gold and the PGM's during the PLATSOL® process. However, the silver minerals are transformed into silver chloride, which can then be recovered from the PLATSOL® residue using conventional techniques. Some South American silver concentrates contain levels of impurity (mostly arsenic) so elevated that the penalties incurred significantly affect the process economics. The present results have shown that a low temperature calcination process transforms the concentrate into a product well suited for traditional recovery treatments. Metallurgical details will be provided, as well as the results of mineralogical studies that helped clarify the process mechanisms.IntroductionSilver occurrences in nature are very diversified, and, therefore, primary silver is produced as a by-product of many base metal and precious metal operations [1], as well as a co-product of most gold ores. However, difficulties can arise when high temperature processes are used for refractory gold ores or copper concentrates, or when the silver concentrate contains impurity elements such as arsenic that trigger high penalties."

Jan 1, 2012

By P. Chris Pistorius

Calcium treatment of alumina inclusions, to convert the alumina to molten or partially molten calcium aluminates, is a well-established treatment for steel, to improve the castability of aluminium-killed steel. However, the role of magnesium in calcium-treated steel is not fully clear, nor is the origin of the several percent of magnesium oxide that is often present in calcium-treated inclusions. To study this, steel was sampled after calcium treatment at an industrial steel plant, and the inclusions identified by energy-dispersive X-ray microanalysis (EDX) on polished sections of the samples (analysing the samples in a scanning electron microscope). The predicted fraction liquid in the inclusion was estimated from the ternary alumina-magnesia-lime phase diagram. Inclusions with higher CaO contents generally had lower MgO contents, indicating that the calcium wire is not the origin of the magnesium in the inclusions; this was also confirmed by wet chemical analysis of the calcium wire. Instead, it appears that magnesium-alumina spinel inclusions form during extended ladle contact after aluminium killing and before calcium treatment. While such spinels have been stated to cause poor castability (clogging the submerged-entry nozzle), it is clear that calcium treatment successfully modifies the spinel inclusions to mixed alumina-lime-magnesia inclusions, where the magnesia content contributes substantially to liquefaction of the inclusions: for typical MgO contents of around 10%, the range of Ca:O ratios which yield liquid (or partially liquid) inclusions is extended substantially to lower Ca:O ratios.

Jan 1, 2006

By Bo Yan, Jiaquan Zhang, Haibo Sun

"Based on the validation of steady-state isothermal mathematical model by a 0.4-scale water model for the single-strand slab casting tundish, the effect of varying pouring temperature on the flow, temperature field, and residence time distribution(RTD) of the liquid steel was studied by a transient hydrodynamic model. Due to the decreasing temperature of ladle stream over a casting period of 50 min, the direction of vortex flow at the downstream side of dam changes to clockwise from the anticlockwise at 4 min after the new teeming, and reverts to anticlockwise direction again at 43 min. Meanwhile, the melt flow state in the dam hole is also varying with time. For conventional isothermal water modeling, the RTD parameters obtained are much different as compared with the non-isothermal ones. For the flow control devices(FCD) design, however, the identical optimal scheme can be concluded from the point of view of isothermal modeling.IntroductionOriginally, tundish was adopted as a buffer and distributor to hold and allocate molten steel for sequence casting upon ladle exchange and to provide a desired steel flow rate to the mould below. With the increasing demand to strand quality, the tundish has become a critical metallurgical reactor to enhance inclusions removal, avoid reoxidation of molten steel, and prevent slag entrapment. The general trends to obtain these metallurgical effects are to optimize steel flow pattern and to extend the residence time of molten steel in the tundish through increasing the volume of tundish and/or using FCDs in the interior of the tundish."

Jan 1, 2012

By Alex Moyano

Due to very demanding environmental rules, and to the incrementing impurities contents in the processed concentrates, Codelco Norte smelter permanently faces new demands for planning the production program with the present fulfillment of the environmental regulation. Accordingly, the CN smelter along with IM2, developed an impurity distribution simulation model, M-DICE, which predicts the impurities behavior for each of the process units of the smelter under different process configurations and concentrates quality. The development of the M-DICE included the gathering of operational data for the process units of the CN smelter, including temperature, oxygen enriched air, matte grade, etc. Then based on a mass balance for each of the process units involved in the smelter a thermodynamic evaluation was done to derive the arsenic fractional distribution among the condensed (matte/white metal/copper/slag) and gas phases. Then, the validated M-DICE was able to predict the arsenic behavior in the Teniente converter processing complex concentrates with high arsenic content, among others. At present, M-DICE is in its last stage of development, and is expected to be a suitable environmental and process management?s tool for the Codelco-Chile?s smelters.

Jan 1, 2006

By Laurentiu Nastac

"This paper describes the development and validation of a comprehensive multiscale modeling approach capable of predicting at the mesoscopic scale level the ingot solidification structure and solidification-related defects commonly occurring during the vacuum arc remelting (VAR) process. The approach consists of a coupling between a fully transient macroscopic code and a mesoscopic solidification structure code. The predictions from the multiscale model, including grain morphology and size, primary and secondary dendrite arm spacings, Laves and NbC phases, tendency for freckling and columnar-to-equiaxed transition, were validated against experimental measurements for a 20-inch diameter VAR alloy 718 ingots. The validated model was then used to investigate the effects of melting rate and ingot diameter on the solidification structure of VAR processed 718 ingots.IntroductionThe objective of this work was to develop a fully transient multiscale modeling approach to get an insight into the effect of processing parameters on the cast micro- and macro-structure during VAR processing. The developed model assists in achieving better control of the ingot solidification structure and to determine trends in the macrosegregation in these ingots. Another objective of this work was to analyze the transient effects of production rate and ingot size on the resultant ingot microstructures. This objective was met by first understanding the effects of the full range of processing parameters typically used in the VAR process. Processing parameters such as power input and heat extraction rate significantly influence the ingot liquid pool size and shape as well as the ingot structure, which in turn will greatly impacts the final ingot quality."

Jan 1, 2012

By Heinz Böni, Christian Ludwig, Bernhard Steubing, Uca Silva

"Chile will soon have to find solutions for dealing with rapidly growing quantities of Waste Electrical and Electronic Equipment (WEEE) due to its strong economy and fast increase of internet and communications technology usage. To support this process, the state of the Chilean recycling infrastructure as well as government, industry and consumer efforts to deal with ewaste were analyzed. Current e-waste quantities were assessed and future flows were predicted using a material flow analysis model. In this model computer hardware was used as tracer equipment for WEEE. Best available numbers indicate that today’s formal recycling infrastructure receives less than 3% of the annual quantities of computer waste. This study represents the most comprehensive analysis regarding e-waste in Chile, identifying relevant streams of e-waste and providing a basis for authorities and producers of electronic goods in order to take the necessary actions to establish an adequate recycling system.IntroductionSince 1991, Chile has experienced a period of strong economic growth. It is amongst the countries with the fastest development in the sector of Information and Communication Technologies (ICT) in Latin America and the number of people with access to ICT has been growing rapidly. The high growth rates of the computer market over the last years are representative for the ICT sector with the consequence that the generated quantities of electronic waste are increasing rapidly [1, 2].Waste Electrical and Electronic Equipment (WEEE) or e-waste is “any appliance using an electric power supply that has reached its end-of-life” as defined by the OECD [3]. Even though the overall waste management in Chile has improved much over the last decade, the issue of ewaste was hardly addressed. Due to the value of the materials contained in computer waste - such as precious metals, basic metals as copper or plastics - it may be assumed that an important quantity is already being recovered. This usually takes place on the informal market under questionable conditions for human health and the environment [1, 2, 4]."

Jan 1, 2008

By Nicola Baldo, Marco Pasetto

"The paper discusses the results of a laboratory study, aimed to evaluate the suitability of the bottom ash from Municipal Solid Waste Incineration (MSWI), obtained from different Italian plants, to be recycled in the lithic skeleton of bituminous mixtures, for base layers of road and airport pavements. The research involved a preliminary study of the physical and geotechnical properties of the bottom ash by itself; it was followed by a mechanical characterization of the bituminous concretes. The traditional Marshall methodology was used to identify the optimum bitumen content; the mixtures were also mechanically checked by means of the stiffness modulus test, repeated load axial test and fatigue test. Because the requisites for acceptance in the Italian Specifications and Standards have been satisfied and given the positive mechanical performances, it has been verified that the MSWI bottom ash can be used as substitution of the lithic materials in the road bases, also with very high contents (up to 81% on the weight of the aggregate). Introduction The incineration of Municipal Solid Wastes (MSWs) provides for by-products which can be mainly classified as bottom ash and fly ash. The first one, corresponding to the 25% on the weight of the wastes to be incinerated, so resulting the principal product of the process, is mainly composed by Silica (Si), Iron (Fe), Calcium (Ca), Aluminium (Al), Sodium (Na) and Potassium (K) oxides, so presenting a composition similar to that of different natural materials. Its metallic fraction can be recovered; the remaining part is usually stocked in dumping or, less frequently, recycled. Bottom ash can be re-utilised in the construction of new infrastructures, especially in bitumen bounded mixtures, because of the inert properties of the binder which covers the grains with a subtle film, that prevents the release of heavy metals. The paper describes a study aimed to design new bituminous mixes for flexible road and airport pavements, realised with the highest content of 4 types of bottom ashes, deriving from different MSWI plants of the Northern Italy. The ashes will be named as BA1, BA2, BA3, BA4 respectively (the origin cannot be specified)."

Jan 1, 2008

By Florian Kongoli

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them. The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags. It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified. The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature. Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

Jan 1, 2006

By Amanda C. Lima, Luiz Augusto H. Terrones, Sergio N. Monteiro

"Fabric from weaved yarns made of jute fibers have been considered as reinforcement for polymeric composites. In particular, these fabrics obtained from discarded sackcloth are presently being investigated as environmentally friendly composites with recycled polyethylene matrix. The objective of the present work was to compare the practical properties and economical aspects of these composites with those of conventional materials such as wooden board and gypsum panels for building application. The comparison showed that, depending on the amount of post-used jute fabric, a cost/benefit analysis favors these composites over the conventional materials.IntroductionThe increasing amount of wastes generated by human activities is becoming a worldwide problem of pollution with growing consequences to the environment. The question on how to dispose these wastes is, therefore, a major global issue. Among the possibilities of it gating the problem, the use of materials with characteristics of being renewable, biodegradable and recyclable is considered an environmentally correct solution. Examples of this type of materials are left over lignocellulosic fiber from coconut husks and sugarcane bagasse [1] that, after the primary extraction of edible pulp and juices, can be recover for industrial application. Nowadays, the main use of these fibers is to reinforce polymeric composites applied as components for building construction and automobile parts [2,3]. In addition to these applications, composites reinforced with residual lignocellulosic fibers may replace conventional furniture and panels made of wood and thus help to reduce deforestation [4].Environmental protection is not the only motivation for recycling natural fiber wastes. In developing regions activities associate with collecting and processing residual fibers provide job opportunities for low-income people. Moreover, if the lignocellulosic fiber is collected as a recyclable waste, it hes the economic advantage of a comparatively cost, which constitutes in a relevant difference as a choice for commercial utilization."

Jan 1, 2008

By Magdelinka Padenkova-Yaneva, Emilia Christova Kostakeva

"One of the methods for waste treatment is composting during which as a result of controlled biological decomposition of organic waste in aerobic conditions harmless materials are received. Composting takes place in suitably designed premises which ensure the optimal conditions for biochemical decomposition of the waste. A usual way to process composting is the spreading of the waste on a base made from reinforced concrete.In the paper the phases and basic technical features of the process of composting, the requirements and properties of the base and the ways of protection of concrete base against corrosion are revealed. Technical decisions for a specific construction site in Bulgaria are shown and the advantage of achieving durability of the concrete constructions in the plant while achieving simultaneous environment protection from pollution is discussed.IntroductionComposting is the process of controlled biochemical decomposition of vegetable and animal organic waste in aerobic conditions as a result of which harmless materials are obtained. The latter have better stability and are rich in humus substances which are useful for agricultural crops and can be used for restoring the soil fertility [1, 2, 3, 4].In modern waste treatment plants a composting technology is adopted in which the waste is spread on a concrete base as piles with certain dimensions [1, 3]. These piles are periodically stirred or air is blown through them in order to ensure the quantity of oxygen required for the process of aerobic decomposition of the organic matter. The fluids and gases formed in the course of the composting are take away in order not to pollute the environment – air, water, and soils. For this purpose the base on which the waste is spread must satisfy certain requirements, and the gases must be taken away and rendered harmless in order to protect the atmospheric air from pollution. This paper discusses the need for protecting the concrete base from corrosion and characterizes the stages and main parameters of the composting process and the possibilities for primary and secondary protection of the concrete base from corrosion. Specific technical decisions applied in a composting facility in the area of the town of Plovdiv are presented."

Jan 1, 2008

By Petr Sulovsky, Pavel Leber, Jaroslava Ledererova, Miroslav Svoboda

"The properties of raw materials used for the production of building materials play an essential role in their choice. Industrial waste materials can in some cases improve the performance of new building materials, when compared with classical raw materials. The addition of waste can however negatively impact some of the building material´s characteristics, influencing its stability, service time, durability, and can introduce undesirable variation of certain characteristics over time. It is necessary that each secondary raw material intended for such use be thoroughly investigated in terms of its chemical, physical, and mechanical properties, with special attention paid to the risk components and risk parameters. It is necessary to make many- sided technological tests in relation to the required characteristics of the resulting materials for each chosen application. Moreover, the limit values for the critical (risk) parameters, which the given secondary raw material must satisfy to be used in a specific technology, need to be defined. Introduction The risk components in the industrial waste materials to be used in the production of building materials fall into two groups: - components that pose a risk of development (instant or delayed) of a process deleterious to the utility properties and durability of the resulting materials. Such processes include volume change (expansion as well as shrinkage), alkali-silica reaction, delayed ettringite formation, thaumassite attack, aggressive carbonation, etc. - elements or components that can, if released from the waste-containing building material, pollute the environment. They involve the so called potentially hazardous elements as well as compounds like fenols, PCB, PAHs etc. From the viewpoint of the presence of both groups of risk components, the wastes can be classified as: • environmentally inert waste materials. They are produced in the largest volumes and do not pose a threat to human health. Their physical and/or chemical characteristics fail to satisfy all requirements for utilization in ordinary production. The aim of technology design is to work them into the building products with suitable utility properties. • easier workable waste materials containing toxic components are produced in large volumes. In spite of the content of toxic components, their physical and chemical properties make them suitable for ordinary production, provided that the harmful substances are immobilized by the chosen technology."

Jan 1, 2008

By Felipe P. D. Lopes, Jr. dos Santos, Sergio N. Monteiro, Frederico M. Margem

"Continuous and aligned fiber composites provide the highest possible reinforcement for a polymeric matrix. In particular, the impact resistance is significantly increased in comparison with a low energy absorbed brittle polymer. For this reason, investigations have been carried out with both synthetic and natural fibers as a way to improve the toughness of polymeric composites. Among the natural fibers, ramie was not yet been studied for its reinforcement effect to make tougher polyester composites. Thus, the present work assesses the impact toughness of polyester composites incorporated with different amounts of ramie waste fibers.IntroductionIn most engineering and other technological areas, the use of materials associated with low energy processing conditions is gaining attention for the possible environmental benefits. This offered an incentive towards the substitution of natural renewable and biodegradable materials for the traditional energy intensive synthetic materials [1]. Natural fibers from both origins: animal, such as silk and wool, and vegetable, such as cotton and jute, are typical examples of those environmentally friendly materials. Low cost and highly reduced processing machinery wear are important advantages of the natural fibers over the most common synthetic ones such as glass fiber and nylon. For these reasons, polymeric composites reinforced with natural lignocellulosic fibers have nowadays been the subject of investigation [2,3].The mechanical strength is one important property of lignocellulosic composites to access the possibility of uses like structural materials for building parts such as doors and panels, as well as furniture. In this case, mechanically strong fibers like sisal, jute, curaua and ramie [4-7] are most convenient. Moreover, the relatively low fiber/matrix interfacial shear stress in these composites is associated with higher impact energy. In fact, a greater energy has to be expended for the rupture of a weak interface. The many cracks that are formed by impact tend to branch during the fiber pullout from the matrix [8]. A larger number of cracks correspond to a greater fracture surface and consequently higher toughness."

Jan 1, 2008

By Tobias Pröll, Bernhard Kronberger, Joachim Rohovec, Werner Hölt, Hermann Hofbauer

"As this is only a first draft, more precise explanations as well as detailed schemes, figures and plots will be included in the final draft. The description og the 100 kW test rig will also be mor detailed as construction is ongoing and will be finished during the summer. Furthermore simulations are to be finished shortly; so details on combustibles and gas concentrations will also be included in the final draft.AbstractOxyFuel combustion is a key technology for the efficient separation of CO2 from fuel combus¬tion (especially coal). Since coal plays a minor role in the Austrian energy mix the application of OxyFuel towards other fuels (biomass, waste fuels) is interesting to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alter¬native fuels is also interesting from a strategic point of view in order to generate knowledge for operation of capture ready cofiring and waste/sludge-incineration plants. OxyFuel uses a synthetic mixture of 02 and recycled exhaust gas where the 02 content may vary. This supplementary degree of freedom allows improved operation especially for low calorific fuels. Heavy fuel oil addition for low calorific combustibles can be omitted when using OxyFuel combustion. Application of alternative fuels (wood, waste wood, municipal waste, sewage sludge) in a 100-kW CFB plant is investigated in combination with process simulation.IntroductionOxyFuel combustion is discussed as one of the key technologies for the efficient separation of CO2 from combustion of fossil fuels (especially coal). Since coal plays only a minor role as primary energy source in Austria, the broadening of the scope towards OxyFuel of other fuels like biomass or waste fuels is necessary to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alternative fuels besides the large coal-oriented projects is interesting also from the strategic point of view. The presented project aims at the generation of knowledge in order to design and operate capture ready cofiring and waste/sludge incineration plants."

Jan 1, 2008

By Daniel Kim, Michael Free, Justin McAllister, Urian Marshall, Shijie Wang

"Cathode impurity levels of electrorefined copper were evaluated based on 1/10* scale laboratory electrorefining tests. Cathodes were evaluated near the top, mid-section, and bottom sections of cathodes on both the set and mold sides and strip and scrap cycles. Slime weights were measured, and slime and electrolyte samples were also evaluated for impurities. Results from these tests have been compiled and compared to evaluate the effects of changes in operating conditions and electrode location on cathode impurities.IntroductionMany types of impurities are commonly found in commercial copper electrorefining anodes. The smelter operations that produce the anodes process concentrates that contain a wide variety of impurities that vary based on the mineralogy of the ore. Most anode impurities are removed during electrorefining. However, a portion of the anode impurities is incorporated into the copper cathode product. The mechanisms by which impurities are transported from the anode to the cathode are not well understood. Some impurities can be transported as anode slime particles to the cathode where they are incorporated into the cathode. Other impurities can be transported as dissolved species that are electrochemically reduced with the copper to become part of the cathode. Although research has been performed on anode slimes and impurities [1-4], there is a need for additional information regarding the relationships associated with electrorefining cycles, electrode faces, local electrode positions, anode impurities and specific cathode impurities. The objective of this study was to evaluate lead, arsenic, and antimony cathode impurity trends associated with electrorefining cycles, electrode faces, local electrode positions, and anode impurities. A variety of techniques including electrolyte filtering, anode heat treatment, high electrolyte arsenic concentration, high arsenic and/or lead in anodes, flocculation of slime particles, and appropriate current density control were used to vary cathode impurity levels. Each test was performed only once for a strip cycle and once for a scrap cycle. Consequently, the results for the individual conditions are preliminary and are not the focus of this study. However, the collective set of data with varying impurity modifying techniques provides a broad range of impurity levels, and the associated trends with respect to lead, arsenic, and antimony are discussed in this paper. Approximately 180 analyses of copper cathode were used to track the antimony, arsenic, and lead impurities. Eighteen anode slime samples were also analyzed for antimony, arsenic, and lead."

Jan 1, 2012

By Yavuz Ali Topkaya, Aydin Rusen

"In this study, zinc and lead recovery from zinc plant leach residue obtained from Çinkur using hydrometallurgical methods have been investigated by laboratory scale experiments. Considering more than one million tons leach residue (LR) rich in Zn (12.43%) and Pb (15.51%) in the stockyard and environmentally hazardous, it is essentially necessary to process Çinkur LR. Zinc and lead have been recovered in two main stages. As a first step, Çinkur LR was releached by using hot sulphuric acid for zinc recovery. About 72 % Zn was recovered by using 150 g/l H2SO4 at 95 oC in 2 hours with a pulp density of 200 g/l. Secondly, for lead recovery brine (NaCl) leaching tests were performed on the secondary Çinkur LR obtained after acid leaching process. In brine leaching while lead recoveries up to 95 % could be attained at a low pulp density, the maximum recovery obtained was 84.9 % at a high pulp density (200 g/l) with 300 g/l NaCl concentration in 10 minutes at 95 oC. Introduction Zinc and lead have been known and used by humans since ancient times and also they are important nonferrous metals [1]. Zinc and lead have different properties thus they are used in various application areas, ranging from automobiles to construction, from batteries to textile. Zinc and lead deposits are widely distributed in the Earth’s crust. The principal ore mineral for zinc is zinc sulfide, Sphalerite (ZnS), and lead sulphide, Galena (PbS), is the main source of lead in the world [2].Although zinc is generally produced from sulphidic ores (ZnS) or concentrates by Roast – Leach – Electrowinning (RLE) in the world, in Turkey, zinc production is based on zinc carbonate ores (ZnCO3), and at the Çinkur plant zinc was produced from zinc carbonate from its establishment to 1997 due to high reserves of zinc carbonate in that region. Çinkur is the only plant in Turkey that produces Zn from primary ore containing ZnCO3 by Waelz – Leach - Electrowinning route [3]. However, due to depletion of local high grade ores, oxidized ore concentrates were imported from Iran after 1997, until this plant was shut down. Therefore, there are two different leach residues (LR) which are Turkish LR (TLR) and Iranian LR (ILR) in Çinkur stockpiles. It has been estimated that the total amount of leach residue is more than one million tons of which the major part is Turkish leach residue (TLR)."

Jan 1, 2008

By Emilia Visileanu, Eftalea Carpus

"Due to the demographic explosion and development without precedent of the consumer society, the capacity to destroy the ecological balance the entire planet life depends on, acquire new dimensions. In this context new approaches on society development are imposing as well as special responsibilities for stopping and preventing Earth destruction and repairing the damage already done. The zero waste is a call to action that has as an aim the changing of current mentality of human society. ”take, use, throw away”. The zero waste is a policy, a way, an aim and represents a new approach planned for the XXI century that include the resources preservation principles, pollution reducing, increasing of the opportunities to create new work places and providing the highest degree of the.1. INTRODUCTIONThe zero waste is a call to action that has as an aim the changing of current mentality of human society. ”take, use, throw away”. The zero waste is a policy, a way, an aim and represents a new approach planned for the XXI century that include the resources preservation principles, pollution reducing, increasing of the opportunities to create new work places and providing the highest degree of the economy stability.2. ECOLOGICAL CONCEPTSA long-living Romania means:The closing of the production cycles, by waste reusing and recycling; the reducing of the use of fossil fuel; the improving of the material qualities, for extending the economical life of the products made by these materials; the reducing of the transport traffic.In this context, ecology, the star science with the ability to conserving and renewal of the environment is making its way, having the following principles:•,everything is bind by everything – is referring to the importance which the environment has for a great number of allied fields;•,everything leads to somewhere – the principle of the indestructible property of material (in nature, there must not exist wastes);•,nature does it the best – ecology becomes the responsible science with the governing of the strategic laws between man and nature, man takes advantage of the natural resources which he cannot create by himself and nature must feel guarded and not destroyed by this alliance;•,nothing is for free – the polluter pays.The protection of the natural environment means:•, its strong knowledge and that of the interactions between the social economic system and the natural system, the foreseen of the most close and most distant consequences of these interactions;•,the rational usage with maximum economical character of the natural resources not depending on their origin;•,preventing and direct fighting against as well on the degradation of the environment caused by man, as on those produced by natural causes;•,the ability to harmonize immediate interest of the human society on long and permanent term, using the natural factors of the environment."

Jan 1, 2008