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By R. P. King

The central idea presented in this paper is straight forward. Some fairly obscure mathematical techniques are presented from the fields of integral geometry and stereology and these techniques are shown to provide workable quantitative relationships from which the liberation spectrum of an ore after comminution can be determined. The experimental data that is required can be obtained very accurately and conveniently by image analysis of polished sections of the original ore. This quantitative mineralogical analysis provides a bridge that can link the worlds of the mineralogist and the mineral process engineer. This paper has been written to introduce this quantitative approach to a wider audience in the hope that the approach will be used more widely and that the basic linear intercept analysis data will be measured for a wider range of mineralogical textures. This could lead to a more comprehensive characterization of typical mineral ores that will be of considerable use in practical mineral processing.

Jan 1, 1991

By L. W. Beckstead

The use of acid ferric sulfate solution as a lixiviant for chalcopyrite concentrates has been of little interest from a practical standpoint due to the formation of a tenacious layer of elemental sulfur which severely impedes the reaction progress. CuFeS2 + 4Fe+3 ?Cu+2 + 5Fe+2 +2s° For example, an acid ferric sulfate leach of chalcopyrite concentrate results in only 12% copper extraction in a three hour leach at 93°C. Experimental results suggest that particle size is the only controllable variable which has a significant effect on the rate of acid ferric sulfate leaching at ambient pressure. Size reduction of the concentrate prior to leaching was exam¬ined using various methods of grinding. Of the grinding methods considered, attrition grinding was found to be the most effective. Leaching of an attritor-ground product (median particle size 0.5 microns) resulted in approximately 90% copper extraction in a three hour leach at 93°C. Energy measurements suggest that the costs associated with attrition mill¬ing are not unreasonable. Evidence indicates that "activation" or stored strain energy is not responsibile for the enhanced reaction kinetics of the finely ground concentrate, but rather the experimental results can be explained simply in terms of the increased surface area due to size reduction. Leaching reaction mech¬anisms operative in the acid ferric sulfate system are discussed and the application of ultra-fine grinding technology to other systems is considered.

Jan 1, 1976

By Yoshisada Michiura, Junko Umeda, Katsuyoshi Kondoh

Rice husks or straws, one of the main agricultural wastes in South-east Asia, have a large possibility to be employed as usefully renewable resources to produce energy and high-purity silica (SiO2), because they consist of about 70% organics such as cellulose or hemi-cellulose, and 20% amorphous SiO2. The former is utilized as bio-mass energy; for example, thermal or electric energy, and bio-mass ethanol. High-purity silica can be used as raw materials in the industrial uses. It would be possible to extract silica elements from rice husks and straws by burning them in air because their main contents are organics. In the previous studies, a strong acid leaching treatment on rice husks before burning was carried out by using H2SO4, HCl and HNO3 to prepare high-purity silica materials. This was available to accelerate the hydrolysis of celluloses and hemicelluloses contained in rice husks, and remove the above metallic impurities. A strong acid leaching treatment, however, is significantly hazardous to environment and human life, and causes an increase of the process cost. In this study, the environmentally benign, harmless to human and economically effective process to produce high-purity amorphous SiO2 materials from rice husks has been established without using strong acids. From a viewpoint of the harmless influence on human body, the carboxylic acids were used in the leaching treatment on rice husks. TG-DTA measurement and GCMS analysis indicated that the leaching was effective for the hydrolysis of celluloses and hemicelluloses contained in rice husks at 473K~873K, which produced the same results in using the conventional sulfuric acid. The metallic impurities could be also removed from the husks via a chelate reaction between carboxyl groups (-COOH) and the metal elements. In particular, it was clarified that cadmium (Cd) were completely removed from rice straws by this reaction. Concerning the burning conditions of rice husks after the acid leaching, it was necessary to supply a suitable amount of air to completely combust organics; for example it required air supplement of 50 ml/min. or more. The burning temperature should be less than 1273K to obtain amorphous structured silica. High-purity amorphous silica materials with 99% or more were prepared from rich husks by applying the citric acid leaching treatment and burning process at 1073K in air.

Jan 1, 2008

By Denise C. R. Espinosa

The amount of secondary batteries are increasing about 15% by year. Among these batteries, it can be highlighted the NiCd ones, due to their high consumption. In Brazil, the consumption of NiCd batteries grown quickly in the last 5 years, due to the dissemination of cellular telephones and other electronic devices. The first step of a process to recycle spent NiCd batteries is the pretreatment through unit operations of mining treatment. The aim of this work is to define a physical pretreatment to conditioning the waste to a pyrornetallurgical recycling process of spent NiCd batteries used in cellular telephones. Batteries were disassembled by hand to release the different components. The studied batteries are basically composed (by weight) of: 78% nucleus, 18% plastic case and 2% circuits. The grinding of the batteries was performed by knife mill and also by hammer mill. After grinding the material was screened and submitted to a magnetic separator.

Jan 1, 2001

By Shubin Wang

Copper(II) and nickel(II) are often recovered from ammoniacal alkaline solutions by solvent extraction using hydroxyoxime extractants: both copper(II) and nickel(II) are extracted from ammoniacal alkaline solutions and, from the loaded organic phase, nickel(II) is selectively stripped with a dilute acid followed by copper(II) stripping with an acid of higher concentration. Since a small portion of ammonia is co-extracted with copper and nickel, the extracted ammonia should be scrubbed using a dilute acid before metal stripping. In the present study, a mechanistic model has been developed in order to support design and control of this process. The equilibrium distribution ratios of copper(II), nickel(II), and ammonia at 298 K using LIX® 84-I (active component, 2-hydroxy-5-nonylacetophenone oxime) as the extractant are successfully correlated by considering the relevant equilibria. Based on these results, quantitative prediction of equilibrium distribution ratios in the process has been made possible, and suitable conditions for the efficient separation of copper(II) and nickel(II) are discussed.

By Satoshi Itoh

Phase equilibria and activities of the components in the liquid lead-antimony-oxygen temary system, which is of fundamental importance for discussing the recovery of lead and antimony from a used lead-battery, have been investigated at 1173 and 1223 K. The two liquid phases of metal and oxide were observed at the temperatures studied, and the tie lines indicating isoactivities were determined. The activities of PbO, Sb015 and Sb203 in the PbO-SbOu and PbO-Sb203 pseudo-binary systems were then obtained by applying the Gibbs-Duhem equation to the phase relation of metal-oxide equilibrium. Both in the pseudo-binary systems the activities exhibit negative deviations from Raoult's law. The vapor pressures of lead, antimony and lead oxide, antimony oxide were calculated by using the activities of the components in the lead-antimony-oxygen ternary system. As a result, an oxidation of antimony concentrated in an anode slime followed by evaporation as antimony oxide Sb406 was found to be considerably effective for the recovery of lead and antimony from a used lead-battery.

Jan 1, 2003

By W. Riekehof

The paper explains required practice and equipment for capturing airborne fumes and particulates in hot-dip zinc galvanizing plants. An economic and technical comparison of enclosure and tank rim suction options is presented. The paper also compares the performance of various filter media in filtering fumes, to determine the effect of changes in flux as well as changes in filter finishlcoating methods. This includes a recommendation for how to achieve the best result with respect to pressure loss and cleaning behavior of the filter.

Jan 1, 1992

By Robin D. Rogers

Room temperature ionic liquids (RTIL) can replace certain traditional organic solvents in liquid/liquid extraction of metal ions from aqueous systems. The very low vapor pressure and non-flammable nature of RTIL warrant consideration of these neoteric solvents for new processing technologies which will reduce pollution, Increase safety, and lower costs. Metal ion separations in RTIL, however, will typically require the use of an extractant and research is needed to identify suitable selective extractants which have appreciable solubility in the RTIL and low solubility In the aqueous phase. Choice of extractant should also take into account the toxicity, expense, and disposal of the ligand.

Jan 1, 1999

By A. V. Tarasov, V. M. Paretsky

"A mathematical model of the low-temperature (soft) nickel oxide reduction (SNOR) in a tubular kiln has been developed including an equation describing changes in the nickel oxide content of the solid material along the length of the kiln; an equation describing the changes in the content of reagents ensuring nickel reduction (i.e., hydrogen and carbon monoxide) in the gas phase along the kiln length; as well as the temperature along the kiln length. The kinetic relationships used for the development of the model had been determined based on experiments conducted specially for this purpose. Model investigations were conducted to determine the distribution of such parameters along the length of the kiln as the contents of metals oxides in the solids, partial pressure of hydrogen and carbon monoxide, variations of the temperature depending on the SNOR process conditions, including the kiln rotation speed. Based on the data obtained, a simplified regression model of the reducing roasting process was developed.IntroductionAt the SeveroNickel complex (Russia) a technology has been developed and is being introduced on a commercial scale for low-temperature (soft) nickel oxide reduction (SNOR) in tubular kilns.The SNOR process has a number of advantages, the main of which are the higher degree of metallization and higher chemical activity of reduced nickel oxide attributable to the lower fusion of the surface of the grains of reduced material due to lower process temperature (800-1000°C) and improved reducing ability of the gaseous phase. However, the fact that the process is conducted in a gaseous phase sets higher requirements to the consistency of its composition necessitating careful continuous monitoring and control of the main process parameters."

Jan 1, 2001

By D. Norman, D. J. Hughes, R. Dashwood, I. McGregor, N. D. Raath

"This paper develops a methodology for predicting spot weld fractures in automotive boron steel grades, such that fracture modes can be predicted accurately in a vehicle or sub-assembly structure. To achieve this, it was necessary to understand the range of complex fracture modes observed in boron steel spot welds and how these are linked to the Heat Affected Zone (HAZ) microstructures and hardness distributions and residual stress.Material data for the HAZ was extracted by simulating the spot welding process using a Gleeble machine; achieving specific weld microstructure in a larger volume which was used in destructive testing. Neutron diffraction was employed to accurately characterize the post-weld residual stresses found inside the weld. The constitutive relations of specific areas in the HAZ where fracture is thought to occur is being incorporated into finite element software to improve fracture prediction of boron steel welds.IntroductionWith the drive for light-weighting and improving passenger safety, lighter and stronger materials are being continuously sought in the automotive industry. The application of boron steel in the Body-In-White (BIW) meets both these criteria by down-gauging thickness of the steel and increasing the strength. As an example, when applied to crash-relevant areas in cars, components have an ultimate tensile strength of 1500 MPa, minimum springback and reduced sheet thickness.To achieve high strength and low springback, boron steel components must be formed and hardened at the same time. This is typically achieved by austenitizing the steel around 900 °C and simultaneously quenching and forming, usually with a hydraulic press and tool-set. Trace amounts of boron, typically 0.005wt%, increase the hardenability of the steel dramatically. This is attributed to the grain boundary segregation of boron, which hinders the formation of ferrite during cooling and forces the transformation of austenite to martensite at high cooling rates, a minimum of25 °C/s."

Jan 1, 2013

By Yuuki Yoshida

Electrolytic manganese dioxide, EMD, is the positive electrode material of primary batteries and the raw material of LMC used as the positive mass of lithium ion batteries and is currently produced by anodic deposition on and harvesting from a titanium anode in acidic manganese sulfate solutions prepared by dissolving high purity of manganese sulfate into sulfuric acid solutions. This paper presents an alternative method of EMD production using a novel anode, Mn2O3 coated titanium, at lower operating temperature than the current process to explore a possibility of manganese recovery from zinc electrowinning solutions. The Mn2O3/ Ti anode prepared by thermal decomposition of a precursor solution containing Mn (II) showed the anodic deposition of MnO2 by constant current electrolysis and the current efficiency was 95% in maximum, while the current efficiency and the crystallographic structure of deposited MnO2 depended on the current density, the electrolysis time, the bath temperature, and the concentration of Mn(II). The deposited MnO2 was successfully harvested from the anode and the recovery rate was 98%.

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

Bottom blown oxygen copper smelting process developed at Dongying Fangyuan Nonferrous Metals shows many advantages such as flexible feed requirement, high productivity, low energy consumption and high direct copper recovery. However, the weak acid generated during the process is not stable which influences the waste management and continuous operation. The amount of the weak acid is determined by SO3 formed in copper smelting process. SO3 can be formed inside copper smelting furnace and boiler at different conditions. Effects of temperature and oxygen partial pressure on the formation of SO3 during copper smelting process have been discussed thermodynamically. Understanding of the mechanisms for SO3 formation will enable the operation of bottom blown copper smelting furnace to be optimized and generation of the weak acid in the process can be managed. The fundamentals developed in this study can also be applied to other copper smelting processes.

Jan 1, 2016

By Norihisa Iida, Yutaka Koshiba, Tsutoipu Masui

"Mitsubishi Materials has many years of experience in the production of oxygen free copper (OFC) and its alloys with a fully continuous-casting process. Four grades of OFC, commercial, electronic, superconductor, and ASTM class I are available according to user needs such as stabilizer for superconductivity, magnetron, and ultra-vacuum systems. Along with Cu-Ag and CuSn, we offer OFC based copper alloys such ·as Cu-Cr-Zr, Cu-Fe-P, Cu-Ni-Si and others, that are suitable for lead frame and connectors. Within the maximum sizes of 260mm X 1050mm for cakes and 385mm diameter for billets, we are very flexible and can adjust the ingot size to customer’s requirements. Other products that we can supply are semi-finished products such as hot rolled sheet, ·forged blank, extruded rod and finished products like mold for continuous casting of steel, ring mold for non-ferrous casting and backing plate for sputtering target.IntroductionMitsubishi Materials Corporation developed mass produced high quality oxygen free copper and. high copper alloy ingots in the 1960's. We produce 60,000 - 70,000 tons annually giving us 22 - 23% share of the world's market.Our oxygen free copper and. copper alloys are produced with a fully continuous casting process using only high-grade copper cathodes from our Naoshima and Onahama refineries. The raw material is melted and cast in' a carefully controlled atmosphere resulting in a product with low impurities and excellent properties.Using a controlled atmosphere it is possible to produce high quality copper alloys including active elements like chromium (Cr), zirconium (Zr), titanium (Ti), and magnesium (Mg) which are difficult to produce using standard batch casting methods.Using our own cakes and ·billets we produce and supply worldwide wrought materials like molds for ferrous and non-femous casting. These products receive special patented thermo-mechanical· treatments resulting in high strength and excellent conductivity with low cost."

Jan 1, 2000

By R. Nilsson

In the present work the sulphide capacities of Ca0-Mn0-Si0, ternary slags have been measured in the temperature range 1798 - 1873 K by equilibrating the slag with a gas-mixture containing CO, CO,, SO, and Ar. The results are compared with the data reported in literature. A theoretical model has been developed in the present work where the sulphide capacity is expressed as a function of the slag composition and temperature. The model enables the estimation of sulphide capacities of complex slags with a knowledge of the capacities of simpler systems.

Jan 1, 1994

By C. A. Pickles

At the present time, pyrometallurgical processes are employed for the recovery of lead from battery scrap. These processes have serious pollution problems, primarily due to the emfssion of sulphur dioxide and airborne lead in the form of dust and fume. In addition it is necessary to dispose of solid wastes and liquid effluents which contain lead and in some cases sodium sulfide-containing compounds. In this work an improved process was investigated for the recovery of lead from battery residue. This involved pelletization of the residue with sodium carbonate and moisture. Then, the pellets were melted without carbon and the .sodium sulphate salt was removed. Subsequently, the molten lead oxide was reduced with carbon. This process minimizes the sulphur dioxide emissions and leads to very low sulfide contents of the sodium sulfate salt

Jan 1, 1992

By Daoxin Wu, Zhong Cao, Yan Shi, Yu Ding, Huanli Yang, Zhongliang Xiao

"2-substituted benzimidazole-zinc and 2-substituted benzimidazole-copper complexes were main components of organic solderability preservative (OSP) in PCB producing process and affect the thermal stability of OSP film. So these four complexes were prepared by 2-substitutedbenzimidazole reacting with zinc ion and copper ion, the complexes crystals were determined by IR, its thermal stabilities were studied by TG method. The results indicated that the thermal stability of 2-substituted benzimidazole-zinc is higher than the 2-substituted benzimidazole copper,and the thermal decomposition mechanism was presentedIntroductionImidazole compounds which is an important heterocyclic compound shows the important value and outstanding prospects[I-3l in field of biological engineering, medicine, and high-performance composites. It's said that imidazole compounds is an excellent new metal surface treatment[4] agent, because it has good reaction activity with metals and can form a chemical layer on the metal surface. The complexes of imidazole were main components of organic solderability preservative (OSP) in PCB producing process and affect the thermal stability of OSP film. The mechanism of imodazole combined with metal and film deposited has been reported, but the opinions about thermal stability of film have bifurcation, let alone the thermal decomposition mechanism of film at high temperature. The complexes were prepared by combining of 2- substituted-benzimidazole with zinc and copper iron, which were studied by IR and TG method, in order to get thermal stability of different complexes."

Jan 1, 2011

By T. Manlyama

The Tamano Smelter of Hibi Kyodo Smelting CO., Ltd. went into operation in 1972. The Flash Smelting Furnace that was originally adapted was equipped with electrodes that were attached to the settler substitute of the slag cleaning furnace. Later the development of our own original coke combustion technology was promoted and a new Tamano Type Flash Smelting Furnace (T-FSF), without electrodes, was put into operation in 1988, T he technology of coke combustion and combustion the burner have continued to improve. As a result the copper losses in the Wag have been reduced as well as a stable operation has been achieved, Furthermore; this has been accomplished while increasing the concentration feed and the matte grade. The current objective is to continue to strive for high matte grade operation and to raise production efficiency while paying attention to the important subject of copper losses in the slag. In this report, the data related to the copper loss in the slag reduction are presented along with the influence of the thickness, settling time and coke. The recent operation conditions of the T-FSF are also presented.

Jan 1, 2003

By Guo Xian Jian

In this paper, an alternative process to recover the value metals from polymetallic gold ore by FeCh leaching was proposed. In the process, gold was recovered by direct cyanidation from the leaching residue, the isolative electrolyte in chloride solution was selected to recover lead, the cementation with copper powder was used to recover silver and the solvent extracting was applied to recover copper and zinc. The total recovery of gold, lead, copper, silver and zinc in the process is 90.8%,96.05%,84.3%,81.98% and 54% to the bullion of gold, lead and silver and sulfate of copper and zinc, respectively. The process conditions selected for FeCh leaching are the temperature of 104°C, leaching time of 6 hours, Fe3+ content of 140 g/l and stoichiometry of FeCl3.

Jan 1, 1996

Lead removal has been problematic in nickel production by electrowinning from chloride solutions, as developed by Falconbridge. The C12 leach liquor needs to be diluted by electrolyte to allow precipitation of the lead prior to electrowinning. This results in higher solution purification costs and an aversion to consider lead contaminated (secondary) feeds. In this paper, the electrowinning of nickel chloride is carried out in a membrane equipped electrolytic cell. When lead containing nickel solutions are fed into the anode compartment and the anolyte is separated from the catholyte with a cation exchange membrane, lead remains in the anolyte due to the presence of a negatively charged chloride complex. The positive nickel ions migrate preferentially through the membrane to the catholyte, allowing a lower lead nickel cathode to be produced. Lead concentration in the catholyte and the cathode product has been tested as a function of lead concentration in the anolyte. Results are presented and discussed.

Jan 1, 1998

By A. P. Paiva

With the aim of establishing a valuable alternative to the conventional methods, studies regarding the recovery of precious metals by solvent extraction have been increasing over the past few years. In this work, the selectivity of extraction presented by Cyanex 471X toward silver is investigated. Simulated chloride solutions considering contents of iron and copper usually present in actual leaching practice were used. The characterization of the aqueous solutions - in terms of the multiple equilibria established by the chlorocomplexes of the different metals and their relation to the total chloride concentration of the base-electrolyte - was successfully carried out by cyclic voltammetry. The results obtained support the important contribution of the electrochemical techniques for the understanding of the overall extraction phenomena.

Jan 1, 1994