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By James Vaughan

Ionic liquids are solvents of interest for applications such as electro- plating, winning and refining of metals. Of particular interest is the possibility of processing reactive metals such as aluminium, magnesium and titanium that cannot be deposited from aqueous solutions. Aluminium has been electro deposited from AlCl3 : ionic liquid mixtures at low temperatures relative to conventional Hall-Héroult smelting. Imidazolium ionic liquids are have been used in the past due to their relatively high ionic conductivity and cation stability. The less studied and less expensive phosphonium ionic liquids systems may provide a viable alternative to imidazolium ionic liquids for certain applications. New information regarding the physical properties and electrochemical behaviour of phosphonium ionic liquid systems is presented.

Jan 1, 2006

By Juan Patricio Ibáñez

Separation of arsenic and copper from Cu-As-H2S04 electrolytes by electrodialysis has been investigated at room temperature. The effects of current density and pH were studied. An arsenic-free copper solution was obtained for all the tested conditions. The transport efficiency for copper ions was found to be higher than 98% after 3 hours' test. Transport of arsenic and copper through the ion exchange membranes was increased by increasing pH and current density. Solution pH was found to be a key parameter for the separation process, since it controls the speciation of the ions to be transported and the formation of unwanted precipitates which reduce the global efficiency of the electrodialysis process. The main conclusion is that electrodialysis is a promising technique to be used in separating and/or concentrating ions of interest in copper electrometallurgy.

Jan 1, 2003

By James R. Craig

The slags generated during gasification of petroleum coke are heterogeneous and con-sist of many different phases. These phases are important because their physical properties affect the operability of gasifiers and because they concentrate many elements that are present in the petroleum coke feed in only minor to trace quantities. An understanding of the chemistry and physical nature of these slag phases is necessary to predict behavior in the gasifier and in considering the ultimate use or disposal of the materials. Slags typically consist of silicate glasses, calcium-silicates, free iron-nickel metallic phases, iron sulfides, and aluminum oxide spinels enriched in iron, chromium, and vanadium. The partitioning of elements among these phases has been analyzed and will be discussed.

Jan 1, 1989

By Dale Zacherl, Andreas Buhr, Rainer Kockegey-Lorenz

"The microporous calcium hexaluminate insulating material SLA-92 has been introduced as an alternative to refractory ceramic fiber and other insulating refractory materials. Key properties associated with this product include: high chemical purity, long term high temperature stability up to 1500 °C, low thermal conductivity up to 1500 °C, and high thermal shock resistance. The properties of the new material and various applications in the steel and ceramic industries have been reported in previous papers. The current paper summarizes the industrial application experiences with innovative refractories based on SLA- 92 and discusses potential new applications in various manufacturing as well as energyrelated industries.IntroductionSLA-92 was introduced to the refractories industry in 1998 by van Garsel, et al. [1] as a new insulating raw material for high temperature applications, followed by investigations [2] of long term temperature stability for this new lightweight aggregate up to 1500°C.SLA-92 was developed as an innovative alternative to commonly used refractory ceramic fibers. It has unique properties regarding chemical purity and mineral composition and is a microporous, silica-free calcium hexaluminate (CA6 – mineral name: hibonite)."

Jan 1, 2010

By R. Kola

Since more than 15 years the Waelz process at "Berzelius" in Duisburg has proved suitable for reprocessing the zinc and lead containing dust and .sludge which inevitably occur in making steel in EAF-plants. The produced Waelz-oxide is agglomerated in a hot-briquetting plant and charged to an Imperial Smelting Shaft Furnace to recover the valuable elements in form of metallic zinc and lead. In view of the actual importance of the dumping problems of the EAF wastes a description of the "Berzelius" treatment route is given but also the situation in Western Europe is illustrated. Dust from stainless steel production is successfully treated in the Scan Dust Plasma Process in order to recycle Chromium and Nickel, while the resulting Zinc-Dust is treated via the Waelz-ISF-Route. For treatment of low Zinc-containing dust, sludge and fines from integrated steelworks, pilot scale tests have been carried out successfully in the Circulating Fluid Bed in order to recover metalized iron and .zinc/lead fume. A 30,000 tpy Demonstration Plant is planned?.

Jan 1, 1990

By Steven I. Baskin

Cyanides are utilized in many industrial applications including preparation of chemical intermediates, electroplating, and' mining, Cyanide has been utilized in chemical warfare operations as well Cyanide is also synthesized and found in plants and animals including man where it is thought to perform multiple functions. A variety of enzymes are known to detoxify cyanide under different conditions. These include rhodanese, 3-mercaptopyruvate-sulfur transferase, thiosulfate reductase, cystathionaseand albumin. Cyanide appears tQ exert its toxic effect primarily by inhibiting cytochrome oxidase? although other enzymes are also inhibited. Therapeutic antagonist categories to treat cyanide include methemoglobin formers such as nitrite, sulfane-sulfur donors such as thiosulfate, metal salts or complexes such as cobalt and cyanohydrin-forming compounds such as dihydroxyacetone or alpha keto-glutaric acid. Advantages and disadvantages of each category will be discussed. Newer compounds under development have been found that may allow for prophylactic therapy for cyanide poisoning with minimal side effects; In addition, portable co-oximetry devices may provide real-time measurement of cyanide in field units.

Jan 1, 1998

By Shilai Yuan, Huimin Lu, Zhijiang Gao, Panpan Wang

"Solvent refining of silicon through using Si-Al melts is a valid method to remove the impurities from metallurgical grade silicon (MG-Si) melt. The thermodynamic behavior of impurities Fe, Al, Ca, Ti, Cu, C, B and P in MG-Si during the solidification of MG-Si was studied based on the available thermodynamic parameters and experimental data. The morphology of inclusions was investigated by Scanning Electron Microscope (SEM). The chemical composition of inclusions in MG-Si and Al-Si melt was analyzed by EPMA. It is found that the amount of white inclusion reduces and most impurities are solved into the Al-Si melts. After solidification of Si–Al alloy using induction heating and acid leaching, impurities can be effectively removed. The solidification of silicon from the Si–Al melt is found to be more effective for purification than general silicon solidification.IntroductionPhotovoltaic energy is one of promising energy resources in a sustainable society because of its inexhaustibility and cleanliness. Although the production and installation of solar cells have increased significantly during the last decade, the cost of solar cell installation is still high. Multicrystalline silicon has now become the main material in the photovoltaic market because of its low production cost and because of the relative high conversion efficiency of solar cells made from this material, which has been studied for a long time [1-3].Electronic grade (EG) silicon (99.9999999% Si) is commonly used as the raw material to produce SOG-Si (99.9999% Si). Silicon produced from the chemical routes restricts the development of solar cells due to environment threaten, high energy consumption and low productivity. Purification of metallurgical grade silicon (MG-Si) is a low cost, environment friendly method. Although several metallurgical processes such as directional solidification, vacuum refining and electron beam melting [4], have been developed, the cost reduction and refining efficiencies for manufacturing silicon is still have to be further optimized.In the purification process, it is difficult to remove boron and phosphorus by the conventional metal refining method. The refining efficiency depends on the segregation behavior of different elements in solid silicon and the liquid phase. The segregation ratios of all investigated impurities were found to be much smaller than the segregation coefficients between solid and liquid Al-Si melts [5]. For instance, the segregation coefficient of B in Si is 0.8 at the silicon melting point (1687K), whereas it is around 0.2 when silicon is solidified from Si-Al melt at 1273K. For phosphorus the segregation coefficient is 0.06 when silicon is solidified from Si-Al melt at 973K°C, which is much less than 0.35 for recrystallization from liquid silicon. Since the segregation coefficient of boron in silicon is 0.8, it cannot be removed by directional solidification."

Jan 1, 2014

By Nickolas J. Themelis

Nearly thirty two million tons of municipal solid wastes (MSW) are combusted annually in over one hundred U.S. Waste-to-Energy (WTE) power plants, thus reducing the use of fuel oil by about 1.6 billion gallons of fuel oil One of the advanced WTE processes is the 0.9-million ton/y SEMASS facility at Rochester, Mass. Most of the combustion in the three giant combustion chambers occurs while the injected shredded wastes are in suspension, i.e., in flash combustion mode. The velocity, temperature, and concentration profiles in the SEMASS combustion chamber were simulated by representing the combustible fraction of MSW by the simplified formula C6HIO04 and using the CFD program Fluent to solve the turbulent energy and mass transport equations. After validation against plant data, this model will be used to examine options for increasing the productivity of WTE combustion chambers, such as optimum distribution of primary and secondary air and oxygen enrichment.

Jan 1, 2003

By Takahiro Furuzono

Saganoseki Smelter and Refinery of Pan Pacific Copper Co., Ltd. started treating copper anode slimes using a unique hydrometallurgical process in chloride media in 1997. The process comprises the following stages, decopperizing, wet chlorination, solvent extraction for gold, silver chloride reduction, and separate reduction stages that treat the gold extraction raffinate with sulfur dioxide gas. Precious metals and rare metals in the copper anode slimes are dissolved in an aqueous solution of hydrochloric acid by oxidative leaching, which is termed wet chlorination. Gold is efficiently extracted from the chlorination liquor by dibutyl carbitol in the solvent extraction stage. Gold is reduced by oxalic acid from goldloaded dibutyl carbitol and recovered as gold powder. The gold powder is cast directly into granules or ingots of more than 99.99% purity without electrorefining. Selenium is recovered as a selenium residue by reduction with sulfur dioxide gas and refined through vacuum distillation. The plant was designed to process 132 tonnes of copper anode slimes per month and has a current capacity of 206 tonnes per month due to several enhancements. Compared with the conventional process, the hydrometallurgical process described here provides some advantages, in particular, a higher product quality, shorter gold-retention time, and reduction in environmental load.

By Travis Knight

Mixed uranium and refractory metal carbide systems have been proposed for space nuclear power and propulsion applications. Solid-core space nuclear reactors could be utilized for low- earth-orbit (LEO) to geosynchronous-earth-orbit (GEO) transfers, manned missions to the moon or mars, and orbiter missions to the outer planets. However, these high performance space nuclear reactors present some challenging materials engineering requirements for operating in a high temperature, high radiation, and hot hydrogen environment. Since the RoverNERVA programs were concluded in 1973, significant advances in ultrahigh temperature materials technology have been made which can be applied to the development of an advanced solid-core nuclear fuel. Nuclear thermal propulsion (NTP) was first studied in the U.S. beginning in the mid-1950's during the RoverNERVA programs. During that time, about 20 rocket reactors were built and tested. More recently, Russian nuclear rocket reactor tests with pseudo-ternary carbide nuclear fuels (U, Zr, Nb)C and (U, Zr, Ta)C have been operated at temperatures as high as 3300 K for one hour. This study examined the processing parameters for fabricating the pseudo-ternary carbide, (U, Zr, Nb)C.

Jan 1, 1999

By Khalid Hattar, Alexander McGinnis, Buchheitm Thomas, Paul Kotula, Luke Brewer

"Understanding the effects of extensive radiation damage in structural metals provides necessary insight for predicting the performance of those metals considered for application in the extreme radiation environment. Predicting mechanical performance after long term radiation exposure is of great importance to extending the life of current nuclear reactors and for developing future materials for the next generation of reactors. A combination of finite element modeling, nanoindentation, and TEM characterization were used to rapidly determine the microstructure and mechanical properties influences of ion irradiation on a standard 3 l 6L stainless steel sample. The results of this study found that ion irradiation and small scale mechanical property testing can be used to characterize extensive levels of radiation damage structure, only when significant consideration is given to ion irradiation depth, surface roughness and polishing condition, the irradiation temperature, and many other experimental parameters.IntroductionFor either the success of next generation nuclear reactors or the extension of current nuclear reactors significantly beyond their designed lifetimes, research is needed into the degradation of the microstructure and mechanical properties governing the performance of the reactor alloys exposed to extreme environments. Although the exact dose and temperature of these nuclear reactor plans may vary, the cladding and other structural components will be exposed to greater dose and at elevated temperatures. To acco=odate these severe exposures, established cladding materials are being testing to longer exposure and new alloy compositions are being considered. [1-3] For neutron test facilities to reach 100 dpa level, exposure times often span several years, significantly limiting the down-select process of potential new materials for extreme radiation environments. Ion irradiation has been used as a technique to provide a look at the effect of irradiation damage on materials in a significantly shorter time frame. Previous work using proton irradiation provides a deep, broad, and relatively uniform defect profile compared to heavy ion irradiation; however, using this type of radiation still requires weeks to months to reach the 100 dpa level. [4] In this research, we investigated the feasibility of using heavy ion (nickel) irradiation and small scale mechanical testing to provide in a few days a first order screening technique for potential alloys that are being considered for advanced testing."

Jan 1, 2012

By C. Hennesmann, D. Maijer, S. L. Cockcroft, P. Yo

"Die cast aluminum wheels are one of the most difficult automotive castings to produce because of stringent cast surface and internal quality requirements. As part of a collaborative research agreement between researchers at the University of British Columbia and Canadian Auto Parts Toyota Incorporated, work has been underway to predict heat transport and porosity formation in die cast A356 wheels. The basic heat transfer equations have been solved using the commercial finite element package ABAQUS to which specialized routines have been added to predict porosity. Preliminary work on predicting porosity formation focused on using the Niyama parameter as a measure of the probability of porosity. The latest version of the model incorporates a new fundamentally based porosity criterion, which takes into account the effect of hydrogen concentration. The development of this model together with its application to a series of cylindrical test castings as well as a production cast wheel are presented.I. IntroductionDie cast aluminum wheels are one of the most difficult automotive castings to produce because of stringent cast surface and internal quality requirements. Microporosity, in particular, is a common defect that can adversely affect wheel quality. The mechanism of microporosity formation in aluminum alloys is complex owing to its dependence on the interaction of a number of phenomena occurring during solidification including the decrease in hydrogen solubility, the decrease in volume, the development of the solidification structure, and the increase in difficulty in interdendritic feeding [1]. As a result, the amount, size, and distribution of microporosity is affected by a large number of casting parameters including thermal variables, melt composition, grain structure, modification, and inclusion content, making optimization by trial-and-error methodologies difficult.The use of criteria functions, based on thermal conditions during casting, offers a relatively simple approach to predicting microporosity. In practical terms, they are useful because they provide a straightforward method of assessing the impact of varying casting parameters on porosity through various thermal parametersl21 such as thermal gradient, cooling rate, solidification time, and solidus velocity. Drawbacks of criteria functions include insensitivity to varying hydrogen concentration and the limitation to qualitative predictions. Consequently, in aluminum alloys, attempts have been made to develop models incorporating the effects of hydrogen gas and microstructure evolution. However, these types of models represent a significant increase in complexity and sacrifice the simplicity and ease of application of the thermally based criteria functions."

Jan 1, 2001

By Tadafumi Adschiri

"Supercritical water can provide an unique reaction atmosphere for synthesizing metal oxide nanoparticles. Due to the drastic change of properties of water around the critical point, including density, dielectric constant and ionic product, the reaction phase with O 2 or H2 gas and the reaction rate and equilibrium can be varied to synthesize new materials or define particle morphologies. In this work, hydrothermal crystallization experiments are performed with several types of flow apparatus that allow convenient manipulation of variables such as temperature, pressure, and residence time. Key features in the flow modes and material preparation are discussed. The proposed supercritical hydrothermal synthesis method has the following desirable features: i) nanoparticles can be produced, ii) morphology of the produced particles can be controlled with small changes in pressure or temperature, and iii) a reducing or oxidizing atmosphere can be applied by introducing oxygen or hydrogen or other gases. An overview of this method is given for functional material synthesis of significant industrial interest including barium hexaferrite magnetic particles, YAO/Tb phosphor fine particles and lithium cobalt fine crystals.IntroductionHydrothermal crystallization, a method of metal oxide formation from metal salt solutions, is typically used at temperatures ranging from 373 K to 473 K. We are developing a new process for hydrothermal crystallizations that uses temperatures in the range of 673 K to 723 K, which is just above the critical temperature of water1 • 8 • In this work, we refer to this process as supercritical hydrothermal synthesis. The supercritical state of water allows one to vary reaction rate and reaction equilibrium by shifting the dielectric constant and solvent density with pressure and temperature. From of our research on material production in supercritical water, we have identified the following specific features of the supercritical hydrothermal synthesis method: (i) ultrafine particles can be produced, (ii) morphology of the produced particles can be controlled to some extent with pressure and/or temperature, and (iii) a homogeneous reducing or oxidizing atmospheres can be provided by introducing gases, such as O 2, H2, H2O 2• and so on.1"

Jan 1, 2000

By Jan Smit

Sulphidic copper concentrates are generally processed by pyrometallurgical means; while oxidative pressure leach processing of such materials has been shown to be technically feasible, there has traditionally been little incentive to choose this route in favour of a smelting option. However, for concentrates with elevated arsenic levels, oxidative pressure leaching offers distinct advantages, as smelter air emission standards and restrictions on concentrate importation have tightened. The current state of pressure leach technology allows for high copper extractions from arsenical copper concentrates, while producing an environmentally stable process residue, without atmospheric emissions of sulphur dioxide or arsenic. In its studies on pressure leaching of copper concentrates, Sherritt has shown that arsenical feed materials can be converted into environmentally stable residues, with excellent copper extractions. The results of recent batch and pilot plant test work are discussed, including the deportments of copper, arsenic and precious metals.

By Zhihe Dou

SHS reaction system has advantages of heat flux density, energy concentration and reaction speed, with sufficient conditions in thermodynamic and kinetic reaction. This paper invented a new technology of SHS metallurgy of preparing melting point alloys and refractory compounds using its own chemical energy. SHS-leaching process for preparing nano boron powder or ultrafine boride powder and SHS-casting process for preparing titanium-based alloy and immiscible alloy were studied. The results indicate that highly active boron powder of greater than purity of 93%, particle size less than 100nm and purity greater than 98.5%, particle size less than 400nm REB6 can be prepared. With SHS-Casting process, the oxygen content of less than 0.59% ferrotitanium, oxygen content of less than 0.5% titanium alloy and ?40-80*100mm large size of CuCr, Cu-Fe alloy ingots were prepared. This technology has greatly enhanced the thermal reduction method added values of preparing metallurgical products and its competitiveness.

Jan 1, 2014

By D. H. H. Quon

Results of a study conducted to determine the properties of iron ore pellets made from Mount Wright and Carol Lake ore concentrate fines with partial and full substitution of bentonite by several organic binders are presented. Carboxy methyl celluloses 7H and 6TL, hydroxy ethyl cellulose (natrosol) and modified guar gum all produce pellets of acceptable wet, green and dry strength. However, when fully substituted, an inorganic binder such as calcium carbonate is required for satisfactory strength development after induration. Mixing the Carol Lake ore with Mount Wright ore in a 50-50 ratio also achieves the same result. The failure of the Carol Lake ore in the pelletization process is attributed to the low hematite content of the ore. The results are very similar to those from the extrusion studies reported earlier (8).

Jan 1, 1989

By T. E. Warner

In order to detect arsenic and antimony in zinc, various electrochemcial experiments were performed involving the electrochemical introduction of sodium atoms into molten zinc using a solid electrolyte. Under high rates, the formation of the intermetallic phase NaZn13 was assumed to form. Under more moderate injection rates of sodium, employing a symmetric "zinc/zinc cell", a qualitative relationship between the current generated during cyclic voltammeuy and the arsenic and antimony concentrations in molten zinc was observed.

Jan 1, 1999

By F. G. Caballero, J. L. Gonzalez-Carrasco, S. Barrius, H. Carreon, M. Lieblich

"The grit blasting is a low-cost technique successfully used to enhance mechanical fixation of the implants through increasing their roughness. As a result of the severe plastic surface deformation, it produces subsurface effects such as grain refinement, hardening and compressive residual stresses which are generally evaluated with destructive techniques. In this research work, non-contacting and contacting thermoelectric power measurements are performed in blasted 316L VM and Ti-6AI-4V specimens using Ah03 and Zr02 particles which yield a coarse and a fine rough surface, respectively. This study correlates the microstructural changes induced by the grit blasting treatment and the limitations and advantages of each of the nondestructive thermoelectric techniques based on the Seebeck effect used to evaluate these biomaterials.IntroductionIt is well known that surface properties play an important role in metallic materials used in bio-medical applications. Since the biological response is correlated directly with surface properties it is comprehensible the intense activity in superficial modification by physics or chemistry methods in this field. Grit blasting, one of the most popular surface modification of metallic biomaterials, enhances the mechanical fixation of the implant through the increase in roughness [1-3]. Roughening is developed by bombarding the surface with a high-velocity jet of ceramic particles, being the final roughness a function of the processing parameters (pressure, distance, time, ... ) and blasting particles (nature, shape, size). As the plastically deformed surface layer tries to expand relatively to the intact interior of the specimen, residual compressive stress gradients develops perpendicular to the surface at shallow depths with a maximum value at a depth in the range of 5 to 60 µm. This surface treatment also may cause subtle variations in the subsurface material properties, such as increased hardness and grain size refinement, which are consequences of the significant plastic deformation through cold work. Blasted affected zones may extend to a depth of up to about 200 µm. The subsurface hardening and the near-surface compressive stress gradient playa beneficial role by retarding fatigue crack nucleation and further growth, ultimately extending the fatigue life of the metallic part [4]. In this work, two non-destructive thermoelectric techniques (NDTT), the non-contacting and contacting thermoelectric power measurements were used to analyze the subsurface induced changes on blasted Ti-6AI-4V and 316L VM specimens using Al2O3 and Zr02 particles. Detailed information on the microstructural induced effects and subsurface mechanical properties were published elsewhere [5-8]. Here the nondestructive evaluation of the involved microstructural changes is used to assess the global subsurface damage. Advantages of using nondestructive techniques during manufacturing are envisaged."

Jan 1, 2012

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 C. E. Abbey

Cobalt, iron and manganese play various roles in copper electrowinning using lead–calcium–tin alloyed anodes. Cobalt catalyzes electrochemical water decomposition resulting in lower anode potential and reduced corrosion rates. Iron reduces cathodic current efficiency, but is used to reduce higher oxidation states of manganese that oxidize organics in solvent extraction. Manganese also produces anode scale and is generally considered a problematic impurity. The effect of the combined interaction of these three metal ions on the anode potential has not been quantified yet. The current work used a three factor, two level, three replicate central composite design of experiments to analyze the effects and potential interactions among cobalt, iron and manganese. The experiments consisted of chronopotentiometric analysis to assess anode potential after 24 h of operation. Higher [Co], lower [Mn] and either high or low [Fe] yielded lower anode potentials. Two regression models were developed to predict anode potential as a function of [Co], [Fe] and [Mn]. A method to estimate electrical energy consumption for copper electrowinning is also presented.