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By Tang Chaobo

According to the principles of simultaneous chemical equilibrium and electronic charge neutrality, the system of Mg(II)-NH3-CO32--SO42--H2O at 25°C has been thermodynamically analyzed. And the rule of solubility of MgCO3(s) in the system is discovered, the high dissolution field of MgCO3(s) is discovered too. Furthermore, the solubility of MgCO3(s) is increased with the increase of the concentration of SO42-, but it is decreased first then increased with the increase of the concentration of all the CO32- and the total concentration of ammonia and ammonium, and decreased with the value of pH being higher. Those results will has important significance on prepare magnesium chemical products and other salts carbonate that are strict with the content of magnesium with carburization method.

Jan 1, 2006

By K. S. Jeong

Since the start-up of the Onsan Smelter in 1979, LS-Nikko Copper has grown into a competitive smelter through continuous development. Several environmental improvements have been carried out, in particular, intensive investments in reducing SOx emissions, such as de-sulfurization plants, fugitive gas capturing and TMS(Tele Metering System). In addition, in recent years LS-Nikko Copper has spent more than 10 million USD every year to improve environmental conditions. In order to be a global leading smelter in every aspect especially environmentally, LS-Nikko Copper plans to inspire environment-friendly minds, co-operate with shareholders, and participate in global conventions. This paper describes the environment improvements carried out at Onsan and briefly introduces a sustainable vision for a green smelter.

Jan 1, 2006

By Masatsugu Morimitsu, Tian Zhang

"This paper presents a novel anode for oxygen evolution in acidic aqueous solutions to produce non-ferrous metals by electrowinning. The method to prepare the anode was thermal decomposition of a precursor solution, and the obtained anode consisted of Ru02-based oxide catalytic layers formed on a titanium substrate, in which the catalytic layer contains nano-oxide particles as the active component. The oxygen evolution potential was lower than amorphous lr02-Ta20s coated titanium anodes so that the cell voltage of electrowinning was further reduced with the amorphous Ru02-based electrode.IntroductionElectrowinning (EW) is used to produce high purity of non-ferrous metals, and the primary metal production of copper, zinc, nickel, and cobalt by EW consumes huge electric energy worldwide, which tends to increase with increasing demand of such metals. The reduction of electric energy consumption is a significant issue for electrowinning industry, which means that the cell voltage reduction is needed to realize more energy-efficient EW processes. Another issue is also indicated from environmental perspectives; i.e., an improvement in EW plant environment by eliminating hazardous byproducts and wastes. Such byproducts and wastes include lead oxide, manganese oxide, and acid mist.We have been developing the anodes for energy-efficient and environmentally friendly electrowinning processes [ 1-11]. The development has been successfully done with the invention of the smart anode, MSA TM (Morimitsu Smart Anode) [ 1-5], which has low polarization for the main reaction and high polarization for the side reaction, in which the main reaction is oxygen or chlorine evolution, while the side reaction is the anodic deposition of each or both of lead oxide, manganese oxide, and cobalt oxide. The anode consists of a valve metal substrate coated with amorphous or less crystalline oxide catalytic layers. One of the typical examples of such oxides is amorphous lr02-Ta20s, and the substrate is normally titanium plate or mesh. The most important point of the oxide is that the amorphization or less crystallinity induce the increase in the active surface area only to the main reaction, not to the side reaction, thereby the polarization of the main reaction being reduced.In this paper, we present the smart anode consisting of RuO2-based catalyst formed on titanium substrates for oxygen evolution in electrowinning. The preparation, characterization, and polarization behaviors of the anodes are shown, and the cell voltage data for zinc or copper electrowinning using the anodes are also presented."

Jan 1, 2012

By Xuewei Lv, Maojun Zhou, Xiaobo Huang, Rende Zhang

"The characterization of the surface roughness of the mineral particles is of vital importance for the studies of the mineral processing. In this study, an evaluation of the roughness of the iron ore particles, with the measurements of size distribution and the measurements of specific surface area with the liquid nitrogen absorption, was developed. The main theory of this method is the fact that the roughness of the particle influences the specific surface area apparently. The specific surface area of the particles can be measured with the laser diffraction method and the liquid nitrogen absorption method. The influence of the surface roughness of the particle can be measured with the nitrogen absorption and cannot be measured with the laser diffraction. Therefore, the roughness can be got by comparing the specific surface area with two measurement methods.IntroductionThe characterization of the surface roughness of the mineral particles is of vital importance for the studies of the mineral processing. There are three main methods for measuring the size distribution of mineral particles: sieving, laser diffraction, and sedimentationl). Many techniques involve sedimentation such as the Horiba2, 3) and the Cyclo-sizer1). In the mineral industry, size distribution is usually determined by sieving because it can be carried out accurately for all particle sizes larger than 45 . The preferred method to obtain the size distribution of finer particles is laser diffractometry. The technique has several advantages: it produces measurements in a few minutes with considerably less labor compared with the cyclo-sizer and for a range of sizes considerably wider in comparison with the sedigraph4). The equivalent-sphere size distribution reported by laser diffractometry is valid for metallurgical calculations and can be routinely used in mineral processing plants. The surface area of the particles can be measured by the BET method of nitrogen adsorption, or it can be calculated from the size distribution. However, the latter calculation requires the size distribution to be accurately known across the whole size range, and assumptions have to be made about the shapes and surface roughness of the particles and presence or absence of pores (see below). The BET method is based on the physical adsorption of gas over the whole exposed surface area and measures the surface area stemming from the roughness and open pores on the surface of the particle5). The calculation of the surface area from the size distribution is usually based on the assumption that all the particles are smooth spheres, without considering the shape and/or roughness of the particles. Determining the surface roughness of the particle with these methods, is the objective of this study."

Jan 1, 2012

By Ruirui Wei, Yanhui Liu, Fangqing Yin, Meilong Hu

In China, Basic Oxygen Furnace (BOF) slag is traditionally used as an aggregate for civil engineering, for road engineering and fertilizer. In order to make full use of BOF slag, the experiments of BOF slag with high temperature roasting has been carried out and the phase transformation is studied. The BOF slag from Chongqing Iron & Steel is roasted in the electric muffle furnace at three different temperature. The influences of the high temperature roasting on change the phase composition of BOF slag was characterized by XRD. The results revealed that SFCA was produced at the high temperature in air atmosphere and melting temperature of slag was lowered. Therefore, if the BOF slag which treated by roasting was utilized in the sintering process, it is advantageous to improve the sintering strength and the formation of the liquid phase and reduce fuel consumption in the sintering production process.

Jan 1, 2015

By Vinay Kumar, Jae-Chun Lee, Abhishek Kumar, Manis Kumar Jha

However, India is rich in ores and mineral, but E-waste recycling is necessary due to the report of national and international studies, which cautioned on the generation, treatment and accumulation of e-waste in India. Current data indicate that the total domestic e-waste generation including imports is around 382979 MT, however waste available for recycling and actually recycled are 144143 MT and 19000 MT, respectively. In which recycling by non-formal and formal sector are 95% and 5%, respectively. On the other hand, India has developed expertise in handling verities of metallic wastes in an organized and safe manner. The development of individual process or combined processes for handling the e-waste is underway. Eco- friendly and energy-saving processes are necessary to comply with stringent environmental regulations. The paper includes the recent trend of e-waste generation, recycling process and its future prospects particularly in India.

Jan 1, 2011

By Anil Saigal, Jr. Fuller, Said Jahanmir

"All-ceramic crowns, including glass-infiltrated spinel composites, are coming into widespread use because of their superior aesthetics and chemical inertness. This study investigates the residual stresses that are developed in these composites as a result of cool down from the glass-infiltration temperature to room temperature due to slight mismatch in the coefficients of thermal expansion and its effect on the mechanical behavior of these composites. Two-dimensional finite element simulations were performed using an object oriented finite element program OOF. The OOF program is a combination of two programs. The first program, PPM200F, is designed to read an image file such as a micrograph. The individual pixels that constitute the micrograph may be collected into groups and their material properties assigned. PPM200F is then used to create the finite element model/mesh that OOF then reads. The average residual stresses are found to be tensile in the spinel matrix and compressive in the infiltrated-glass. There is large variation in residual stresses and strains from location to location with presence of locations at which the glass is under tensile stress. The crack initiation and initial propagation in glass-spinel composites is at the glass-spinel interface in both the glass and the spinel. The presence of residual stresses can lead to lower crack initiation stresses and degrade the mechanical properties of the composites.IntroductionGlass-infiltrated spinel ceramics are in clinical use as core materials in all-ceramic crowns and as inlays and onlays (1-3). Advantages of ceramic composites include near net-shape forming with high strength in the infiltrated state. Besides, spinel is quite translucent and may potentially be used without a veneer. However, these ceramic composites are subject to damage accumulation from repeat oral contact loading and often fail after a few years of use (4). This paper examines the residual stresses that are developed in these composites, after cooldown from the glass infiltration temperature to room temperature, due to the slight mismatch in the coefficients of the thermal expansion of the two phases."

Jan 1, 2001

By L. B. Tsymbulov

Sulphide melts formed in the course of smelting of nickel and copper-nickel feed (matte) actually are sulphide-metallic melts since sulphur contained in the melts is in deficiency with respect to metals. The level of metallization is rather relevant feature of sulphide melts and is widely used in calculating material and heat balances for pyrometallurgical processes. Despite of the above parameter? importance, the investigators have no single opinion on what should be understood under metallization level and the method of its determination. In the present study we present the results of our own experimental and theoretical researches that have allowed determination of some mechanisms of sulphide melts? crystallization. Based on the mechanisms revealed new scientifically justified approach has been offered for determining level of metallization of the components present in sulphide melts. It has been demonstrated that sulphur distribution between the melts is substantially different from generally accepted concept.

Jan 1, 2006

By J. C. Riani

The release of heavy metals into the environment is increasing among others due to human activities such paint and pigment industries, tanneries, and metal finishing industries. Among metal releases, chromium is notable because this metal is carcinogenic. Thus, the aim of this work is to use an ion exchange system composed of one cationic resin column and one anionic resin column in order to adsorb the chromium (III, VI) from chromium electroplating effluents with the objective of recycling the water. The methodology consists of chromium adsorption tests using the ion exchange resins system with Purolite the 850 (polystyrene matrix, functional group quaternary amine) and Purolite C 150 (polystyrene matrix, functional group sulfonic acid). The contaminated solutions were passed through the columns with the assistance of peristaltic pump. Samples of the outgoing solution were taken in order to control the conductivity and pH and analyze the metals. The effects of the feeding outflow on the chromium adsorption were evaluated. The results show that the quality of the water collected at the end of the process is within the Brazilian standards about the discarding of toxic substances in the environment (CONAMA 357/05). This makes possible the recycling of water into the process and also its discharge in the rivers.

Jan 1, 2006

By Thomas Gliick, Jianming Lu, David Dreisinger

"The Boleo project of Baja Mining (Vancouver) will process a mixed oxide-sulfide ore using an acid oxidation and reduction process in seawater to extract copper, zinc, cobalt and manganese. Copper will be extracted via SX-EW as copper cathode, zinc will be recovered as a zinc sulphate monohydrate crystal and cobalt will be produced as a cobalt cathode product after phosphinic acid extraction. Manganese may be recovered from the final solvent extraction raffinate by precipitation as manganese carbonate.The development of the cobalt recovery process (solvent extraction and electrowinning) will be discussed. The pilot plant solvent extraction circuit and subsequent bench and small pilot testing of cobalt electrowinning will be discussed. The Boleo project will produce approximately 1708 tonnes per armum of cobalt metal when fully commissioned.INTRODUCTIONThe Boleo property is held by the Mexican company, Minera y Metalllrgica del Boleo S.A. de C.V. (MMB). MMB is owned 70% by Baja Mining Corp. and 30% by a consortium of Korean companies consisting of KORES - Korea Resources Corporation, LS Nikko Copper, Hyundai Hysco, SK Networks and Iljin Copper. The project is fully financed and is now under construction with an expected startup in early 2013 .Average annual production, for the first six years for each of the metals is forecast as: 56,697 tonnes of copper cathode, 1,708 tonnes of cobalt cathode and 25,364 tonnes of zinc sulphate monohydrate. The project has an average life-of-mine cash cost (based on the three year trailing average metal prices, as of December 31, 2009, in accordance with SEC guidelines) of -$0.29/lb Cu, net of by-product credits for cobalt and zinc and with no credit for manganese production. There is the potential to produce up to 220,000 tonnes per armum of manganese carbonate (- 100,000 tpa contained Mn) via the relatively simple addition of a small number of unit operations to the proposed plant. The recovery of manganese metals from the manganese carbonate intermediate material is discussed in a separate paper in this proceeding."

Jan 1, 2012

By John A. S. Green, J. Gilbert Kaufman, Subodh K. Das

"The aluminum industry is a leading proponent of global sustainability and strongly advocates the use of recycled metal. As the North American primary aluminum industry continues to move offshore to other geographic areas, such as Iceland and the Middle East, where energy is more readily available at lower cost, the importance of the secondary (i.e., recycled metal) market in the U.S. will continue to increase. In the past, the recycling industry had been synonymous with the collection of aluminum beverage cans. However, as the opportunities for aluminum recycling have multiplied in motor vehicles, building and construction, and aerospace, these market are getting additional scrutiny for optimization of recycling strategies.Accordingly, the secondary industry can now draw upon a much wider range of product forms and alloys for its raw material, but this in turn brings issues of alloy sorting, impurity content, and control as the material is remelted and recycled into new product forms. The purpose of this paper is to take an integrated, industry-wide approach to look at the recovery of material from demolished buildings, shredded automobiles, and aging aircraft, as well as from traditional cans and other rigid containers. Attempts will be made to assess how the different alloys used in these separate markets can be recycled in the most energy efficient manner.IntroductionIn his recent book “Aluminum Recycling”[1], Mark Schlesinger points out that in traditional extractive metallurgy, the raw material used to produce a metal is mined from the earth and then is separated from other gangue minerals and impurities. In aluminum recycling, however, the ore body consists of scrap metal found on the ground, rather than in it. He further notes that scrap comes with its own variety of gangue and impurities such as painted coatings, other metal attachments, and even dirt and other contaminants. So, while the recycling process still requires some refinement and expenditure of energy, the effort and energy involved is much less than traditional mining."

Jan 1, 2008

By Reuben John Mathew

"Oxygen evolution is the main anode reaction in industrial copper electrowinning. The oxygen bubbles do not conduct electricity, thus increasing the electrolyte resistance. The oxygen bubbles formed at the anode rise to the surface, occupying a larger volume of the electrolyte at the top of the cell than at the bottom. This oxygen bubble concentration gradient contributes to a gradient in electrolyte resistance and consequently a tendency toward uneven current distribution. This phenomenon increases the chance for uneven growth on the cathode and/or short-circuits, particularly on the lower portions of the cathode. This issue may be ameliorated by increasing the charge transfer resistance for oxygen evolution down the height of the anode. This concept was studied by solving the current distribution for a 2-D model of a copper electrowinning cell using COMSOL.IntroductionA copper electrowinning tankhouse aims to operate at the highest current density that will deposit on the cathode a layer of copper metal possessing the desired physical and chemical characteristics. The operating current density is directly related to the physical nature of the copper deposit on the cathode (Figure 1), limiting a copper electrowinning tankhouse to some operating current density that produces acceptable copper deposits.[!] The ratio of the operating current density to the limiting current density is typically around 0.3.[2] If the limiting current density for a cell could be raised, the operating current density could also be raised and thus result in savings in capital cost for a tankhouse. [3]The average operating current density in a copper electrowinning plant is 270A·m- 2 .[4] The value for average current density, however, obscures the fact that the face of a cathode does not experience this value equally. Indeed, the current density varies along the height of an electrode and is independent of the height of the electrode.[5] This phenomenon partly explains why the lower portions of a cathode tend to display a rougher copper deposit.In order to utilize a higher operating current density but still remain at 30% of the limiting current density, the limiting current density must be raised, but it is affected by the mass transfer regime at the electrodes. The mass transfer regime is currently poorest at the lower portions of the cathode and this is part of the reason for the tendency for poor cathode deposits to occur at the lower portion of the cathode.[6]"

Jan 1, 2012

By Dao Su, Kelang Mu, Yufeng Guo, Jinghua Zeng, Tao Jiang

"The influence of high pressure roller grinding (HPRG) on sintering of iron concentrate fines was investigated. Results of mini-sintering tests showed that assimilation temperature of iron concentrate fines decreased from 1230 ? to 1220 ? and assimilation time was shortened from 10 min to 5 min when the iron concentrate fines was pretreated by HPRG. Sinter pot tests showed that the yield of sinter increased from 60.33% to 72.92% , tumble index increased from 44.35% to 46.66%. The investigation indicated that, after being pretreated by HPRG, iron concentrate fines are improved in ballability and the fraction of fine particles increased, resulting in the improvement of granulation property and reactiveness in solid state reaction. As a result, sintering of iron concentrate fines were strengthened.IntroductionWith the rapid development of iron and steel industry and the decrease of high-grade ores, the imports of iron ore are increasing continually. It is of immensely strategic importance for development of iron and steel industry and energy security in our country to make good use of iron concentrate fine which is low price, high grade and has a refractory sintering property. When iron concentrate fine is used in sintering, granulation property of sinter mixture and permeability of sinter bed get poor. As a result, yield and quality of sinter fall down. Many researches show that, when HPRG is used in pelletization, quality of pellets is improved dramatically. Meanwhile, HPRG has a low energy consume, a large handing capacity and it is benefit for environment protect. At this theme, strengthening of sintering of iron concentrate fine pretreated by HPRG was investigated in this paper."

Jan 1, 2012

By Ahmadzadegan. Arash, Anil Saigal, Michael A. Zimmerman

"In this study, the rheology of liquid crystalline polymer (LCP) melts through simplified 2-D and 3-D die geometries is simulated using Polyflow™. It is known that rheological properties of LCPs are close to long chain polymers and their directionality is close to those of small molecule liquid crystals (SMLCs). As a result, different rheological models (both viscoelastic and generalized Newtonian) for long chain polymers in Polyflow™ were investigated based on the available capillary rheometer data. By varying the parameters in these models, it is possible to adjust the effect of shear viscosity, normal stress differences and relaxations times on the rheology of the polymer. The free surface of the extrudate coming out of the die is simulated and the amount of die swell for different types of rheological models is compared. This study indicates that the Bird-Carreau model best applies to thermotropic LCP materials as quantified by die swell. Since the rheology of the LCPs affects the orientation of the crystals, the result of this simulation can be further used to predict the orientation of crystallines inside and outside the die.IntroductionAny rod like molecule or crystal tends to orient itself in the direction of shear as it moves within a flow. Since polymers consist of long chains of molecules, they experience the same phenomena when flowing in the melt condition. For most polymers, the molecules change direction and distribute uniformly in space during the solidification. However due to the higher inertia of the crystals in the liquid crystalline polymers, the oriented crystals will keep their order during the solidification and as a result the final product will show anisotropy in material properties."

Jan 1, 2012

By S. Redik, C. Wenzl, D. Gregurek, A. Spanring

Zinc is a component of many input materials used in various pyrometallurgical processes, for example primary lead and zinc production from Pb/Zn ores and recycling processes dealing with zinc-containing residues (e.g., copper recycling, WAELZ process). Hence, zinc and its compounds are present in the respective metallurgical vessels and interact with the refractory lining. In the present work the zinc attack on the refractories out of various primary and secondary furnaces is briefly introduced and discussed. At the prevailing processing temperatures in the metallurgical vessels, zinc oxide is highly corrosive for the brick components. The knowledge of the wear behavior is based not only on a detailed chemical and mineralogical characterization carried out on provided post mortem samples, but also on FactSage calculations. This together with results obtained by practical testing in the RHI pilot plant represents an important prerequisite for product development and brick selection for the individual customer application.

Jan 1, 2016

By Mao Chen, Baojun Zhao, Zhixiang Cui, Leonel Contreras

Viscosity is one of the important physiochemical properties of metallurgical slags which is important for slag tapping, metal loss in slag, freeze lining and fluid dynamics. High temperature viscosity measurements are time- and cost-consuming and the number of experiments is limited. Viscosity model is an effective way to predict the viscosities of the complex slags at high temperature. However, a reliable viscosity model can only be developed on the base of accurate experimental data. A unique high-temperature viscosity measurement apparatus developed at The University of Queensland enabled accurate viscosity data to be measured for the “FeO”-SiO2-CaO-MgO-Al2O3 system in equilibrium with Fe. An accurate viscosity model has been developed based on Eyring’s theory and extensive viscosity measurements. The viscosities of copper smelting, converting and cleaning slags over a wide range of compositions and temperatures can be predicted and applied in the process control.

Jan 1, 2016

By P. P. Knight

The Parkes Process is an important step in the pyrometallurgical refining of lead bullion and it is estimated that more than 50% of the Free world's primary silver production is processed by this route. The metallurgical efficiency of the process can have a significant impact on the overall refining costs, particularly with regard to zinc consumption and the costs of working up the silver-rich crusts?. Several authors have used mathematical or graphical methods in order to calculate the minimum required zinc additions and to study the merits. of alternative. operating procedures, but these methods are of necessity very cumbersome and are only able to deal with relatively simple systems. The paper explains how a computer model was developed which simulates the Parkes Process accurately and can predict the effects of changes made in operating methods. Examples are given of some of the findings and their relevance to the practical conduct of the process is? discussed.

Jan 1, 1990

By Mituo Tougo, Mitsuo Tokunoh, Takayasu Kisaragi, Fuminori Chiba

We have about 200,000 tons/year of dross residue produced after the collection of aluminum from the dross generated during the aluminum remelting process. 130,000 tons of the dross residue is used as a steel deoxidant or a cement material, and the remaining 70,000 tons is abolished and buried in the ground at authorized places. The dross residue is increasing along with the increase in the aluminum production. This situation will grow more serious with a large amount of aluminum window sashes which have been mass-produced since 60's and will return before long as scraps. Our effort is being directed to the development of technologies which enable the dross residue to be recycled and reused for some purposes such as road aggregates, refractories and others, in such a way as to comply with the social requirement which gives prfority to the recycling industry, as well as to the environmental preservation.

Jan 1, 2000

By H. U. R. Kattentidt, W. L. Dalmijn, T. P. R. de Jong

Sensor controlled sorting is a promising technique for the upgrading of scrap aluminium alloys. In a universal detection system of Delft University characteristic features are extracted · from the material particles by means of cameras. Examples are size, texture, edge-structure, homogeneity, and colour pattern. Additional sensors are added for higher selectivity: electromagnetic detection, light transmission, spectral reflection and more. Signal processing theory learns that a classification of particles fundamentally improves as the number of independent features increases. At the laboratories of the Delft University a test bench is available for the development of advanced multi-sensor quality control and sorting systems. It is based on a software system for detection, segmentation and classification of particles, which was especially developed for this application. Work is now in progress for high-speed detection and sorting of non-ferrous alloys, including aluminium casting and wrought alloys. A recently developed actuator design enables positive sorting into more than 3 fractions of particles that are randomly orientated on a flat conveyor belt.

Jan 1, 2000

By Matti Hämäläinen

Outokumpu has developed a new chloride leaching process, HydroCopper?, for copper concentrates. The process utilizes the cupric ion as oxidant, which is able to dissolve chalcopyrite. After solution purification monovalent copper is precipitated as cuprous oxide, Cu2O, using sodium hydroxide. Copper product is produced from Cu2O by reduction, melting and casting. An essential part of the new process is chlor-alkali electrolysis, which regenerates the reagents used. All impurity metals are removed before Cu2O precipitation, because otherwise they would report to the copper product, impairing its quality. A multistage solution purification scheme has been developed consisting of firstly, chemical precipitation of impurity metals by pH increase, secondly, cementation of silver and thirdly, removal of trace multivalent ions using ion exchange. This paper describes the characteristics of solution purification in the HydroCopper? process based on the laboratory tests and pilot runs made by Outokumpu Research Oy.

Jan 1, 2003