Search Documents

By Jianjun Wang, Jiaqing Peng, Lingen Luo, Zhenbang li, Yinghe Lin

Copper removal from ferronickel by FeS has been exploring studied. It is found that the decopperizing agent FeS makes the copper removal in ferronickel effectively. The effects of FeS addition amount, carbon content in ferronickel and experimental temperature were investigated. The results showed that the removal rate of copper in ferronickel increased with the amount of FeS increasing. When the dosage of FeS is 20% (mass percentage)，the removal rate of copper can reach higher than 11%. The rate of copper removal rises with the amount of carbon content increasing in ferronickel. When the amount of carbon content is 1.86%, the removal ratio of copper is 41.3%. Higher experimental temperature promotes the copper removal reaction in certain extent. The flux is acidity and weak oxidative can also promote the reaction of copper removal.

Jan 1, 2015

By Rainer Schmid-Fetzer

"Isothermal solidification can be used to form strong bonds at low temperature which remain solid at much higher temperatures. The exploitation of this principally known technique for new high temperature processing steps and applications in electronic assemblies is the aim of this study. Three basically different variants of this bonding process are given. A comprehensive metallurgical screening is performed and the feasibility of binary material systems is given on a quantitative scale. Very attractive systems are spotted that have never been studied before. Detailed examples for the realization of bonding with complex ternary and multilayer systems are given. A highly innovative example is the chip stack or wafer to wafer bonding of unmetallized Si or SiC at 250°C. The proposed bond remains stable above the melting point of Si and enables entirely new semiconductor manufacturing steps. An improved die bonding process was proposed and verified experimentally.1. IntroductionIsothermal solidification can be applied to form strong bonds at relatively low temperature which remain solid at higher temperatures. The general principle of this type of joining processes is illustrated in Fig. 1. An interlayer of a low melting component, Lo, is provided as a foil or a thin film coating between the high melting joint components, Hi. The assembly is heated under moderate pressure to the bonding temperature, T 8 , and a liquid filler forms, either because the melting point of Lo is exceeded or due to a eutectic reaction between Lo and Hi. This molten filler initiates a rapid interdiffusion or reaction diffusion between Lo and Hi and the subsequent approach to an equilibrium state results in isothermal solidification. The solid phases formed at T 8 in the joint region exhibit a remelt temperature above T8 •"

Jan 1, 1996

By V. M. Paretsky

The basic work conducted by Prof. A.Yazawa has demonstrated that in order to ensure single-stage white metal production by autogenous smelting of copper sulfide raw materials, it is most favorable to use highly basic slags, in particular oxide systems CaO-FeO-Fe2O3-Sio2. he special studies have been conducted in the Gintsvetmet Institute to investigate the composition and structure of slags produced on a semi-commercial scale when testing the KFP and FBP processes for white metal smelting, as well as the slag obtained in a full-scale KFP furnace at the Almalyk copper smelter. The investigations conducted have demonstrated why production of high-grade matte or white metal is associated with lower loss of copper in slag in a series: silicate slag I silicate-calcium slag I ferrite-calcium slag.

Jan 1, 2003

By D. Morin

A general study of gold refractory arsenopyrite-pyrite concentrate bioleaching has been carried out including two continuous bioleach testworks at different sizes, namely one at a laboratory scale with a 100 I unit at a 2 kg/d dry solid flowrate and the other at a pilot scale at a 100 kg/d dry solid flowrate. Both tests show a 80% bioleaching of arsenopyrite in about four days of treatment and with the same kinetic. Pyrrhotite is attacked at the earlier stage of the bioleaching but pyrite remains unaffected. The weak potential of oxidation associated with the decomposition of arsenopyrite and the abundance of arsenite leads to a high grade of elemental sulfur in the bioresidue which consumes the major part of the cyanide during the gold recovery. Furthermore. the arsenite and ferrous produced in solution have to be oxidized to obtain a stable precipitate in the waste products and as outlined in previous works of other authors on this subject the addition of iron to obtain a Fe/As molar ratio at least above 3 is necessary. The agitation equipment used in the pilot unit allowed an optimization study calculation for scaling-up the design and power requirements of an industrial installation. For the pretreatment of a gold refractory As high-graded concentrate the reagent cost has the greatest part in the operating cost of the biooxidation step due to the necessary retreatment of the biosolution. In that conditions the power cost is quite marginal. actually it is significant for the treatment of pure pyrite.

Jan 1, 1991

By Colin Dessemond

Since 1950, the traditional process has been dominating the production of lithium compounds from spodumene ores to sustain the lithium market because of its economic viability and the markets need for technical grade (99.5% purity) product. This traditional process includes thermal conversion, acid roasting and lithium leaching. However, this process has not been challenged and very few studies have tried to explain its limitation (95% lithium yield) or optimize the thermal treatment. Here, α to β spodumene conversion and lithium extraction were performed in a rotary kiln on a 2 mm to 2 cm spodumene concentrate instead of a micrometric one using a 1050 °C, 30 min conversion treatment and 250 °C, 30 min, 30% H2SO4 excess leaching treatment. X-Ray Diffraction analyses were performed on the converted material to determine the conversion rate by Rietveld analysis. It was observed after thermal treatment that the α-spodumene particles fractured and divided while the impurities remained compact. A sifting was performed after thermal treatment and it was determined that 65% of the initial mass became finer than 180 μm. X-Ray diffraction analyses and lithium content measurement were performed on both fractions and it was determined that the finer fraction had a very high lithium content of 3.24 wt%. Lithium extractions were performed on both fractions separately. While the coarser fraction’s lithium yield was only 61% the finer fraction’s lithium yield went up to 99% without any additional treatment. These observations may open more economical ways for the traditional process by potentially bypassing two third of costly steps such as grinding.

By W. K. Connor, O&apos

Thermal Treatment Technology Division Albany Research Center, U.S. Dept. of Energy Oregon. This evaluation included a characterization study and direct smelting tests conducted in a bench-scale electric arc furnace (EAF). In contrast to other thermal treatment technologies considered for these wastes (i.e., fluidized bed combustion), direct smelting in the EAF can process 100% of the wastes without prior beneficiation, and utilizes solid oxidant additions (in this case iron ore) rather than air to oxidize the carbon. This solid oxidant addition is advantageous because it results in the production of several value-added furnace products. These products include cast iron resulting from the reduction of the iron oxides, baghouse dust containing virtually all of the zinc from the residues, and a clean (nonhazardous) slag product suitable for recycle as concrete aggregate or construction fill. Offgas from the smelting furnace also holds potential as fuel gas for cogeneration. The direct smelting tests conducted thus far were successful at producing the desired furnace products, exhibiting the potential for complete recycle of the waste pile. A cast iron product of comparable quality to conventional cast irons was produced, at nearly 80% iron recovery to the metal. The slag product was determined to be nonhazardous, based on the EPA TCLP. Lead and zinc partitioning to the dust product was greater than 99%. The material balance over the furnace indicates that for every ton of feed processed, 540 lb. of cast iron, 600 lb. of slag, and 150 lb. of dust would be produced. Energy consumption was roughly 1.10 kWxh/lb of feed material. Prior experience suggests that these figures measured in the bench-scale furnace would translate to 0040 to 0.50 kWxh/lb at the industrial-scale.

Jan 1, 2000

By Jacques J. Eksteen

Metallurgical accounting around toll treatment smelters pose a number of challenges. This paper reviews the requirements for good sampling practice, and how conflicting requirements for good furnace operation and design often makes reliable closure of the metallurgical balance tenuous at best. Typical physical causes of variance and bias will be identified. The propagation of error (in the form of variance) will be discussed for a copper smelter.

Jan 1, 2006

By He De-wen

Based on the principle of life cycle assessment (LCA), municipal solid waste management (MSWM) was analyzed by life cycle inventory method. According to the system expansion and substitution method, the content and frame of life cycle analysis is summarized and applied to municipal solid waste. On the basic of feasibility research of life cycle analysis on MSWM, the paper put forwards complete and concrete ?three changes? measures under life cycle analysis on MSWM. Some aims of MSWM can be achieved under above conditions of LCA on MSWM: to improve the current system efficiency of MSWM; to enhance the serve quality of MSWM, to increase recycle garbage from MSW; to reduce waste amount and reach minimization and innocuity aim of MSWM; to help the departments of MSWM to get over all difficulties to realize their ideal goals.

Jan 1, 2009

By Jun Enriquez

Kennecott Utah Copper aims to extend anode furnace campaigns to more than three years. As part of that goal improvements are sought on anode-furnace tuyere-area refractory performance. Kennecott and Praxair developed high pressure nitrogen refining for the Oxidation Stage which shortened anode furnace fire refining cycles by up to two hours per cycle. Future developments include optimizing the Reduction Stage’s steam-gas reforming and achieving coherent jet tuyereless refining.

By Akira Yazawa

Experimental results for the distribution ratios of various elements between the slag, matte and/or copper in the silica-saturated copper smelting system were summarized. The experiments were carried out under an oxidative smelting condition with S02 gas flow, and also a reductive smelting condition equilibrating with metallic copper or iron. To evaluate the results thermodynamically, the availability of one atom cation base expression for the constituent compounds is emphasized from both of theoretical and practical standpoints. Both of oxidic and sulfidic dissolutions in slag are postulated for some elements such as copper, nickel and lead., and the experimental results are reasonably explained thermo-dynamically. The results for the mutual solubility between matte and ferrite slag and the distribution of minor elements between liquid copper and ferrite slag are also discussed.

Jan 1, 1983

By R. Ressel

Keywords: ferrovanadium, thermodynamics, phosphorus Recyclable material is rapidly gaining in importance as a source of raw materials in industrialized countries. This is also the case in the production of ferrovanadium, where, increasingly, materials such as discarded capacitors, spent catalysts, slag, dust and sludge are used. As the V-content in the raw material varies greatly, the demands on process technology are very high. The share of perturbing elements depends very much on the source of the raw materials, which, in turn, makes a corresponding optimization of the various refining steps necessary. The raw materials are mostly available as oxides, which means that carbon, silicon or aluminium are used as reducing agents. Thermodynamic calculations were used to show especially the behavior of vanadium and phosphorus at different process conditions.

Jan 1, 2005

By Vincent Menard

The purpose of the present work is to demonstrate the removal of manganese from a neutral leach zinc-rich solution ([Zn] =150 g/L) at 80°C by oxidative precipitation using a gas mixture of sulphur dioxide (SO2) and oxygen (O2). In order to determine the optimum conditions for manganese removal, several bench-scale semi-batch experiments were performed, where the effects of ORP and gas mixing were investigated. These tests showed that SO2/O2 is a fast and effective oxidant for removing manganese down to ppm level as long as the appropriate ORP is attained/maintained and gas transfer kinetics are optimized.

Jan 1, 2006

By Asmo Vartiainen

Background of Direct-to-Blister Flash Smelting is discussed; especially slag chemistry relating to copper solubility, slag fluidity and impurity behavior. In December, 2000, Mini-pilot Flash Smelting test runs were carried out at Outokumpu Research Oy to produce blister copper from Chilean concentrate and white metal and from a mixture of them. Tested slag types were iron silicate slag, ferrous calcium silicate slag and calcium ferrite slag with different slag compositions and different concentrate/white metal ratios. The test runs were successful. The fluxing effect of copper oxide was clearly demonstrated and ferrous calcium silicate slags remained fluid on a very wide liquidus range. The distribution of arsenic between ferrous calcium silicate slag and blister copper is much higher than between iron silicate slag and blister copper. This successful test run with the new slag type offer new possibilities in Direct- to-Blister process design.

Jan 1, 2003

By Adam Powell, Salvador Barriga, Matthew Earlam

"The inert anode is a key enabling technology for dramatic energy and emissions reduction in extractive metallurgy. In molten salts, the materials challenge is nearly insurmountable: the anode must conduct electrons at high temperature in a pure oxygen and molten salt environment. A solid electrolyte, e.g. zirconia, between the salt and anode removes the molten salt stability constraint, and can act as a container for a liquid metal anode. This can be liquid silver for oxygen-generating inert anodes, or several metals for natural gas-fueled anodes; it is possible to switch between these modes. The solid electrolyte brings several other benefits: it eliminates molten salt contamination of the anode gas, creates a reducing environment enabling low-cost steel vessels, increases current efficiency, and eliminates carbon contamination of the product. New developments presented here, including current collector and low-cost anode designs, amplify these benefits for producing aluminum, magnesium, rare-earths, and other metals.IntroductionReactive metals such as magnesium, aluminum and rare-earths play increasing roles in efficient transportation and clean energy. In response to new fuel economy standards, automotive OEMs are planning large increases in use of aluminum and magnesium to reduce vehicle weight. Rareearth permanent magnet motors and generators exhibit better power-to-weight and efficiency than induction motors and other designs, making this today's primary motor technology for hybrid and electric vehicles, and for wind turbines. Nickel metal hydride (NiMH) batteries with lanthanum are dominant in hybrids. In 2011, transportation comprised 28.6 out of 103.1 EJ of US energy consumption [1] and 1,845 out of 5,471 million metric tonnes (MMT = 109 kg) CO2e of US greenhouse gas (GHG) emissions [1], creating big targets for economy-wide reductions.Unfortunately processes for making reactive metals for these applications are very inefficient and heavily-polluting. In primary aluminum production, Hall-Heroult cell electricity use [2] is more than double the reaction enthalpy due to heat losses through frozen cryolite side-walls and anode gases, graphite anode plants add significant energy use and GHG emissions [2] (see Table 1). Magnesium is even worse: silicothermic reduction by the Pidgeon process in China produces about 85% of the world's magnesium using coal or coke gas [3]. Chloride electrolysis begins with high-purity MgO and requires carbochlorination or hydrochlorination and costly chloride dehydration [4]—rendered unnecessary for aluminum by the Hall-Heroult cell. Production of neodymium and lanthanum with graphite anodes leads to inconsistent carbon content: small cells make 1 kg batches for analysis, sorting and sale by carbon content, with very high labor and analysis costs. And vertical electrodes give no incentive to reduce anode effect: some reports indicate that China's rare-earth metal industry emits more CF4 and C2F6—with global warming potential (GWP) 6500 and 9200 times CO2 respectively—than China's aluminum industry [5]."

Jan 1, 2014

By J. Hamisch

Climate policy regarding perfluorocarbons (PFCs) may have a significant influence on investment decisions in the production of primary aluminum. This work demonstrates an integrated analysis of the effectiveness and likely economic consequences of different climate policy options. In our study we first compare atmospheric observations to the available estimates of PFC emissions for the baseline years 1990 and 1995. We then present projections for regional emissions of PFCs from the aluminum industry using the MIT Emissions Projection and Policy Analysis model under different policy scenarios. Abatement costs for emissions of PFCs and C02 are compared in the context of the Kyoto Protocol.

Jan 1, 1999

By Ji-He Wei

Keywords: stainless steel, AOD refining, side and top combined blowing, mixing characteristics, water modeling The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon-oxygen decarburization) refining process of stainless steel have preliminarily been studied on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model have more reasonably been determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics has been examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a well mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from top lance could make the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27° between each tuyere, and five side tuyeres with an angular separation of 22.5° or 27° between each tuyere. The relationships of the mixing time with the gas blowing rates of main-tuyeres and sub-tuyeres and top lance, the angle between each tuyere, and the tuyere number have been obtained.

Jan 1, 2005

By O. Forsén

In the first part of this paper is studied the behaviour of small amounts of impurity elements? in the solidification of copper anodes. In the second part the dissolution of these impure anodes in sulphate based electrolysis is discussed. The first part is introduced with practical examples, the .model of solidification of impurities during the solidification of anode copper. According to this model the solidification structures of anode copper are strongly influenced by both thermodynamic and kinetic factors. Thermodynamics determine the microstructure of anode copper, but kinetics can alter the composition of melt to such that there is formed unequilibrium structures during the solidification, especially when the residual melt is solidified. The electrolysis experiments have clarified the behaviour of impuririties in the electrochemical dissolution in sulphate. Based copper electrolysis. In this study it is widely investigated to what extent any impurity elements or oxides will dissolve. In copper electrorefining. With the aid of the electrochemtcal experiments it was possible to fulfil quantitatively the qualitative results accomplished by microstructure studies.

Jan 1, 1985

By S. Rick Gilbert

In the course of producing a final metal product, smelters, refineries, and other metallurgical facilities produce wastes which often come under the ?scrutiny of Federal and state regulatory agencies. Many of these wastes contain combinations on zinc, copper, lead, cadmium, nickel or other metals. Frequently in the form of reverts, dusts, or sludges, these metal-containing wastes are often buried in a landfill or speculatively accumulated for future action. Environmental liability can be reduced in many cases by selecting,-a recycling facility which can re-process the waste for.' metal recovery. Encycle, at its hydrometallurgical facility Corpus Christi, has Successfully processed a variety of metallurgical by-products and wastes and returned those contained metals to commerce.

Jan 1, 1995

By Malsuzaki. Kenji

A mathematical simulation model of the Imperial Smelting Furnace operation has been developed for purpose of improving the furnace operation. The model consists of top, shaft and bottom regions. Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rates, and those in the top and the bottom regions are based on heat and materials balances under a steady-state condition. Longitudinal distributions of process variables such as temperatures of gas, sinter and coke, gas composition and fractional conversion under a practical operating condition were calculated. With this model, the furnace performance under various operating conditions also can be shown reasonably predicted.

Jan 1, 2003

By G. L. Liu

"Deformation Banding ( DB ) in cold rolled mild steel has been experimentally established by microstructure investigation. Deformation banding model includes such deformation mode when it is applied to rolling texture simulation. The cause for the occurrence of deformation banding is the reduction of the total work for plastic deformation through a relaxation of the deformation constraints. In the first DB model, all grains are assumed to band from the first deformation step. Such an unrealistic assumption has been eliminated in the new model by the introduction of a banding criterion based on an energy minimizing approach. The prediction is closer to the measured texture by applying banding criterion and setting critical resolved shear stresses (CRSS) ratio for { 110 } and { 112 } slip modes to 0.85.IntroductionBased on the continuum theory of plastic flow and deformation mechanism of crystallographic dislocation slip, Taylor's FC ( Full Constrain ) theory [1] has been widely used in texture modeling. As the process of cold rolling of sheet materials produces a microstructure consisting of elongated or equiaxed flat grain or cell, the ""lath"" and ""pancake"" relaxed constraints ( RC ) models [2, 3] were introduced as the successful improvements over the classical FC model. It has been also recognized that crystals may split into different orientations during deformation and the term deformation banding is used to describe such deformation processes [4, 5]. Lee et al. [6, 7] pointed out that the success of the RC theory in predicting textures depends on the physical processes of deformation banding. They developed so called Deformation Banding ( DB ) model by considering DB in the longitudinal plane to be accounted for by the RC method and allowing DB in the rolling plane. DB model was applied to simulate the texture development in bee case [8], the predicted bee rolling textures are in reasonable agreement with the measured textures. In the first DB model, however, all grains are assumed to band right upon the first deformation step. A banding criterion was formulated [7] which states that DB will occur if the work used in DB model is less than that in RC model. Such criterion has been incorporated into the original DB model for texture simulation and is referred to as DBC ( Deformation Banding Criterion ) model."

Jan 1, 1998