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By Chang-Young Choi

Korea Zinc commenced zinc production in 1978 with a capacity of 50,000 tpa. Since then, continuous investments have been made and resulted in Korea Zinc now being the biggest zinc and lead producer in the world. In the course of increasing zinc production capacity, the company management realized that the company needed a lead smelter to prevent the solid waste disposal problems by treating the lead containing solid waste. This paper begins by briefly stating the objectives and the roles of the lead smelter at Onsan. It describes the QSL process and the TSL process, and further extends the description of the TSL process, through which harmless inert solid waste could be produced for secure final disposal. It is also mentioned that the TSL process plays an important role in the integration of zinc and lead production. Throughout the paper, a positive attitude in handling the environmental issues in the non-ferrous smelting industry is emphasized. Finally, a solution for the solid waste disposal problem in the zinc and lead industry is proposed, with which the environmental issues can be an opportunity rather than a crisis. The current operation at Ousan suggests the future direction of the non-ferrous smelting technology that all of the zinc and lead producers should pursue.

Jan 1, 2003

By R. Luo, R. V. Kumar

"The co-deposition of cobalt and nickel as a binary alloy has been studied by both cyclic voltammetry and long-period controlled-potential electrolysis. Cyclic voltammetry experiments showed that the cathodic current density for the mixed Co-Ni (Co-Ni=1:3) electrolyte is noticeably higher than that obtained on electrolyte containing single CO2+ or Ni2+ (II) salt of the same ionic strength. The onset potential observed for the mixed salts electrolyte was also less cathodic (negative) than that for the single metal salts, respectively. The effects of a number of operational and compositional parameters on the co-deposition of cobalt and nickel were studied. The parameters under investigation include cathode (deposition) potential, temperature, CI-/Sol ratio in the electrolyte, the amount of additives such as H3B03, and acidity of the electrolyte.Optimum operational conditions were established for the deposition of cobalt and nickel binary alloy. These results are discussed with respect to feasibility of reclaiming cobalt, nickel and chromium from mixed superalloy scraps by melt-refining (under nitrogen and/or ammonia), followed by electrorerining of cast anode for co-depositing Co/Ni and thermal decomposition of chromium nitride for recovering chromium metal."

Jan 1, 1997

By Wei-ling Wang, Ryosuke O. Suzuki, Xiang-ning Meng, Miao-yong Zhu

"A finite-element thermal-stress model of continuous casting mold is conducted to predict deformation of copper plates and its change with different cooling structure. The results show that deformation behavior of copper plates is mainly governed by cooling structure and thermal- mechanical conditions, deformation amount is related to structure geometry, and a small deformation mutation occurs in cooper-nickel boundary due to different properties. The maximum deformation of hot surface centricities of wide face locate at 100 mm below meniscus and that of narrow face locate at meniscus and terminal of water slots and significant curvature fluctuations on both sides of copper-nickel boundary. The maximum deformation of centricities is increased up to 0.05 mm with thickness increment 5 mm of copper plates, and maximum deformations are only depressed 0.01 mm and 0.02 mm with increments of 1 mm nickel layer thickness and 2 mm water slot depth respectively.IntroductionIn conventional continuous casting of steel, a large amount of sensible and latent heat of molten steel dissipate in primary cooling zone and make continuous casting mold under enormous heating load giving rise to thermal stress, deformation, high-temperature fatigue and creep not only depress mold life-span, but reduce casting stability [1] Many studies focused more on heat transfer, solidification and shrinkage of solidifying shell to provide inverse proposals for optimizing cooling system and even designing new taper of mold [2,3], but it is generally useless to those of having been manufactured or being put into production. Therefore, mold-related forward problems show necessity to be discussed deeply, and stress and deformation distributions based on special thermal conditions in mold should be analyzed in order to explore suitable cooling structure of mold directly. Samarasekera et al. [4] examined heat flow and distortion of two-dimensional longitudinal sections and investigated effect of cooling water velocity, copper plates thickness and carbon content on formation of rhomboidity and longitudinal comer cracks. O'Connor et al. [5] developed a three-dimensional mathematical model to compute thermo-mechanical state in thin-slab mold and calculated temperature and deformation of mold wall to assess roles of various process parameters on impacting mold life. Thomas et al. [6] predicted temperature, distortion and residual stress in mold and indicated increased distortion requires increased remachining, which reduces mold life and increased residual stress increases the probability of a catastrophic crack failure. Park et al. [7l determined heat-flux profiles in funnel-shaped and parallel thin-slab molds based on an inverse heat conduction model and thermocouple temperature measured in-plant and put them into three- dimensional finite-element thermal-stress model to predict temperature, distortion and residual stress of mold wall. Korie et al. [SJ focused on prediction of temperature, distortion and residual stress in mold and in particular to clarify that mold life is significantly affected by temperature and its rigidity, but little effect by mechanical including clamping force, bolt prestress, friction and ferrostatic pressure. Meng et al. [9l predicted temperature and thermal stress in a slab mold and analyzed effect by cooling system geometry and casting speed quantitatively. In present study, a three-dimensional finite-element thermo-mechanical model with type-switched element is transformed from previous heat-transfer finite-element model [9l, and mold deformation is simulated in order to shed light on thermo-mechanical behavior with special thermal conditions and different mold geometry at high casting speed."

Jan 1, 2013

By Markus Aspiala, Fiseha Tesfaye, Pekka Taskinen

In this paper, the standard thermodynamic properties of Ag3Sb and Ag6Sb intermetallic compounds have been studied by the solid state EMF-method, using Ag+ ion conducting β- alumina and AgI. The intermetallic compounds were synthesized from pure substances in evacuated silica ampoules and their formation were confirmed by the SEM-EDS analyses. The EMF measurements were made on electrochemical cells of the type [Ag | β-alumina | Ag-Sb] and [Ag | AgI | Ag-Sb]. The usage of β-alumina electrolyte, in this study, enabled thermodynamic measurements of the Ag-Sb-intermetallic compounds above 710 K, hitherto unreported. Based on the new experimental data, thermodynamic properties of the Ag-Sb-intermetallic compounds have been determined. The obtained experimental values have been compared with the available literature data.

Jan 1, 2015

By M. A. Neri

A lead-free solder alloy Sn-57.5Bi-0.5Ag has been developed by mechanical alloying and foundry processes, and has great potential as a lead-free solder system, to low temperature applications. The mechanical alloying powders show a microstructure different to the microstructure obtained by the foundry process for the same alloy. Its melting point of 142°C is slightly higher than that of eutectic tin- bismuth solder. Examination of the microstructure revealed that eutectic microstructure is refined by the mechanical alloying process Ag additions. The lamellar structure of tin-bismuth gradually disappeared with the process of mechanical alloying, while intermetallic compounds AgaSn phase was formed. The Cu-Sn intermetallic compound layer formed at solder-copper interface is the Cu6Sn5 phase. Keywords: Lead-free solder, Microstructure. Mechanical alloying

Jan 1, 2003

By A. E. Torma

In recent years the copper industry has gained considerable economic stability. An essential part of this industrial wealth is attributable to the successful application of bio-mediated heap and dump leaching techniques in the recovery of copper from low-grade resources. This study evaluated the leachability of a chalcopyrite conlentrate using naturally occurring mixed culture of predominantly Thiobacillusferrooxidans and Thiobacillus thiooxidans. For the effects-of pulp density, the overall reaction rate constant (k) and the order of reaction (n) have been determined to be 1.93 h-1 and 1.36, respectively. Cyclic voltammetric measurements revealed that intermediate reactions are involved in the chalcopyrite oxidation. Using the Price approach, it was shown that the dissolution of chalcopyrite is solid state diffusion controlled.

Jan 1, 1992

By Kenneth P. Michalek, James E. Kelly, Jonathan A. Dantzig

"Many investigations have been reported regarding the simulation of continuous casting with emphasis on in-mold heat transfer. These analyses have been limited, however, because they require either estimation or measurement of the characteristic heat transfer between the ingot and the mold. In this paper, a self-consistent model 'is presented for calculating the heat transfer between a solidifying continuous casting and the mold, in the context of the continuous casting of steel. Using both thermal and stress analyses, the air gap formed during continuous casting is calculated and used to compute the heat transfer coefficients. Iteration between the thermal and stress analyses is used to determine a self-consistent solution. IntroductionThe continuous casting process for steel is illustrated schematically in Fig. 1. Molten steel is tapped into a tundish from which it flows at a controlled rate into the continuous casting mold. The initial shell of the casting forms in the mold by transfer of heat from the metal through the mold wall to the cooling water. The remainder of the casting is solidified by application of water sprays, and/or radiation cooling below the mold.Heat transfer in the mold portion of the process is important because it controls the formation of various defects which are deleterious to subsequent processing. Examples of defects formed in this region are surface irregularities, such as cold folding and oscillation marks, and more serious defects, such as longitudinal or transverse cracks. A more catastrophic problem which may occur is a breakout, in which the shell ruptures and molten steel is discharged in an uncontrolled way."

Jan 1, 1986

By G. S. Hill

A large amount of the stereological error associated with liberation studies can he eliminated by assessing areas instead of linear intercepts. The presentation of a simple geometrical model as a stereological 'worst case' allows calculation of the worst possible grade/recovery curve for a given assemblage of areas. The true results are expected to lie in the window between this worst case and the hest possible case, represented by uncorrected data. The width of this window typically corresponds to an error margin of about 5% grade at a given recovery. An indication of where the data lies within the range of possible grade/recovery results may he obtained from a qualitative analysis of the locked section complexity. Assemblages consisting of texturally complex locked sections (ie. containing many mineral nuclei) are likely to exhibit minimal stereological bias and therefore will tend to lie close to the uncorrected side of the grade/recovery window.

Jan 11, 2011

By K. Tozwa

The electrical conductivity of electrolytes for copper electrorefining and electrowinning processes has been reported by many researchers since 1911. The experimental results show that the conductivity increases with an increase in sulfuric acid concentration and decreascs with an increase in copper concentration. In pure copper sulfate solution, however, the conductivity increases with an increase in the copper concentration. After confirming the conductivity of pure and acidified copper sulfate solutions experimentally, the concentrations of hydrogen ion and free (not hydrated) water in the electrolytes were estimated and it was found that the relation between the conductivity of acidified copper sulfate electrolytes and the products of concentration of hydrogen ion and free water is linear. Accordingly, the conductivity of acidified copper sulfate electrolytes increases with an increase in sulfuric acid concentration and decreases with an increase in copper concentration.

Jan 1, 2003

By J. D. Miller

Gold adsorption from cyanide solutions by activated carbon has been studied at great length during the past decade. Findings from past research are reviewed and discussed with respect to structural features of various carbons, including carbon black, activated carbon, graphite and diamond.

Jan 1, 1991

By Young-Chul Kang

The Onsan Copper Smelter of LG-Nikko Copper Inc. is a unique plant, which has been operating two smelting processes since 1998. The operation of the first one was started in 1979 with a capacity of 80,000tpy of copper in concentrates utilizing Outokumpu flash- smelting technology. The other one was started in 1998 based on Mitsubishi continuous process with a capacity of 160,000tpy of copper in concentrates. Through several expansion projects, the total smelting capacity of both processes is expected to reach 430,000tpy of copper in concentrates towards the end of 2002. This article describes operation advantages of having two different processes at one plant and comparative operation results in terms of productivity, impurity distribution, energy consumption and environment issues and etc?

Jan 1, 2003

By Yuanbo Zhang, Zhixiong You, Li Qin, Guanghui Li, Tao Jiang

Low-grade manganese oxide ore is generally characterized by high iron content. In this work, sulfidation roasting of an iron-rich manganese oxide ore with elemental sulfur was characterized. The experimental results indicated that manganese dioxide can be selectively reduced over iron oxide by using elemental sulfur. The manganese phases in roasted product included low-valence manganese oxide, manganese sulfide and manganese sulfate, while those of iron mainly depended on the sulfur addition. Iron oxide would only be reduced or sulfidized at larger sulfur additions. The effect of roasting temperature and S/Mn mole ratio on the phase transformations was also investigated; extractions of Mn/Fe by sulfuric acid were evaluated. An extraction of Mn greater than 95% was obtained while that of Fe was controlled less than 10% under the optimal conditions.

Jan 1, 2016

By Kliment Y. Hakobyan

A new technology for treating molybdenum sulfide concentrates has been developed. It includes roasting the concentrate in a special regime with water vapor, cooling and neutralizing exit gas, oxidation roasting of rhenium containing MoO2, and the extraction of rhenium from exit gases. This technology allows economically efficient and environmentally safe processing of molybdenum concentrates: The degree of molybdenum extraction is 98.8%, rhenium-90%, sulphur-98.4%. The technology also ensures high extents of extraction of selenium and tellurium as well as the fixation of sulfur in the form of sodium sulfide or elemental sulfur.

Jan 1, 2006

By Anna Franzkowiak, Dean Gregurek, Alfred Spanring, Angelika Ressler

In order to determine the most suitable refractory products and improve the lining lifetime for the diverse furnaces used in the nonferrous metal industry, corrosion tests are performed at RHI’s Technology Center. The practical facilities include the cup test, induction furnace, rotary kiln, and drip slag test described in this paper, which enable a comprehensive understanding of the chemo-thermal brick wear on a pilot scale. The corrosion trials are performed with actual slags generated during operations at a customer’s plant. To determine the highest influencing wear parameter, every single test is combined with a detailed mineralogical investigation and thermochemical calculations performed using FactSage. Based on the results, tailored refractory solutions for the nonferrous metal industry can be provided in combination with trials conducted at the customer’s site.

Jan 1, 2014

By G. D. Sandrock

The science and technology of roan temperature rechargeable metal hydrides began about 1969 with the discoveries that the intermetallic Compounds LaNi5 and TiFe could be, conveniently hydrided and dehydrided at roan temperature and modest H2 pressures. Subsequently, this lead to the development of a broad family of REE-containing AB5 hydrides and numerous applications that make use of the extraordinary H2-absorption and reaction-heat properties of these materials. Some of the applications include H2 storage, compression and separation, as well as heat pumping, heat to mechanical energy conversion and electric energy storage. This paper briefly reviews the fundamental phenomenology of metal hydrides, the history of the use of REE's in rechargeable metal hydrides, the practical engineering properties of these materials and the applications that have evolved around them. The rechargeable nickel metal hydride battery, a new vial alternative to NiCd cells, stands at the forefront of the applications.

Jan 1, 1992

By Yuanbo Zhang, Yongbin Yang, Guanghui Li, Zhengwei Yu, Yufeng Guo, Tao Jiang, Xiaohui Fan, Youming Hu

"Composite agglomeration process (CAP), as an innovative method for preparing blast furnace burden, was developed and has been put into operation in China. CAP is different from traditional agglomeration processes of iron-bearing materials involving sintering and pelletizing. Compared to the traditional agglomeration processes, CAP is characterized by several strengths such as permission of diverse iron-bearing materials in production, obvious improvement of permeability in the feed bed, decreasing the fuel consumption and remarkably increasing the productivity of sintering machine. Furthermore, the use of the composite agglomerates prepared with CAP is capable of obviating the negative effects caused by the differences in quality of sinter and pellets on the operation of blast furnaces. This paper mainly presents an overview of the principle and applications of CAP.Development Background and Principle of CAPhe traditional agglomeration processes including sintering and pelletizing have been the two predominant methods for preparing ironmaking burden from iron-bearing materials. Sintering is a way for agglomeration by heating the coarser fine ores (general granularity 0~10mm). The mechanical strength of irregular porous sinter is obtained by the solidification of molten phase at high temperature process. It has been shown that the production of high basicity sinter (R=1.8~2.2) is characterized by low energy consumption and high efficiency compared to low basicity sintering. Meantime, the finished high basicity sinter is characterized by good mechanical strength and metallurgical performance. Pelletizing is another way for agglomeration by firing wet green pellets, which are balled from the fine grained iron ores or concentrates. Based on the differences of chemical compositions, the finished pellets can be divided into acidic oxidized pellets, fluxed pellets, magnesium-bearing pellets, and so on. The acidic oxidized pellets are the dominant products of modern pelletizing."

Jan 1, 2012

By P. Maraboutis

Iron removal by precipitation as jarosite from Fe-Ni-Co sulfate solutions, (synthetic or real, resulting from laterites leaching) has been investigated. Precipitation was carried out at 95 C, and at an initial pH 1.6, which was either kept constant with CaCO3 or Li2CO3 additions, or left to drift with the evolution of the reaction to lower values. The precipitation of K-, NH4- and Na- jarosite was initially examined using synthetic solutions. In all cases, hydronium ions were incorporated into the precipitate as well. Residual iron in solution was lower (0.2-1 g/1) and equilibrium was achieved faster (within 4-8 h) when precipitating K¬jarosite at constant pH, using CaCO3 for neutralization. Nickel and cobalt losses were small. Na- jarosite precipitation was also studied from real solutions with high initial iron content, under constant pH=1.5, controlled with CaCO3 additions, and it was shown that low residual iron concentration in solution (0.3-0.5 g/1) can be achieved again, with relatively small nickel and cobalt losses. The thickening and filtration characteristics of the precipitates were excellent in all cases examined.

Jan 1, 1988

By Denise C. R. Espinosa

Rechargeable lithium batteries are one of the most promISIng technology in battery development. Although Li ion batteries have been used as an alternative to the more polluting and less performing Ni-Cd batteries, Li ion batteries have limited life and their disposal is uncertain. It is imperative that valuables from wastes, such as lithium, should be recovered. The main objective of the present work was to characterize secondary lithium batteries for cellular phones. This was done using unit operations of mining processing, x-ray diffraction (XRD), chemical analyses and the rmogravimetric analysis (TG). The unit operations were hammer mill grinding, knife mill grinding, size separation and magnetic separation. After the hammer grinding process, the plastic cases were almost intact, however, they have released the cylindrical lithium batteries themselves and these parts correspond to 70% of the total battery weight.

Jan 1, 2001

By K. Sarveswara Rao

"Any innovative approach made in non-ferrous metallurgical industry centers upon developing new processes, saving materials, improving production quality, and bornagain materials. Aqueous processing is commonly used to treat lean grade or more complex ore bodies. Its sustenance largely depends on energy and environmental compliance including water and wastewater management. The present paper focuses the importance of using particle size distribution and surface area measurements during ammoniacal dissolution of a Cu-Pb-Zn sulphide bulk concentrate and with an overview of the effect of water salinity on the process chemistry and residue mineralogy. Accordingly, an effort is made here to discuss the emerging perspective and highlight the recent successes and trends in terms of energy savings in non-ferrous hydrometallurgy.IntroductionThe nature and structure of the global energy industry is likely to change significantly in the 21st Century. Rabago et al [1] have comprehensively discussed how the mining and minerals industries can adapt to the challenges and opportunities posed by trends and drivers in global energy use. According to the authors, the drivers of sustainability include water, efficient energy use, climate modification, transportation technologies and energy security. Sustainability and competitiveness for the minerals industry will depend on natural capitalism, resource efficiency, new processes, saving materials, improving production quality, born-again materials and the solutions economy. Based on this motivation, the theme of the present paper is centered upon applications as relevant to energy and sustainable development in non-ferrous hydrometallurgy."

Jan 1, 2009

By P. K. N. Raghavan

This paper identifies potential technologies for Carbon dioxide abatement from the mining and metal industry with special reference to the Aluminium industry. Mine reclamation could contribute to this effort to successfully reach the greenhouse gas (GHG) emissions reduction commitments for a nation. An overview of GHG production by the mining and metal industry together with a review of principles used to set the context in which specific options for GHG reduction are described. Options for GHG reduction in the mining and metal industry include reforestation, Addition of soil amendments or neutralizing agents, CO2 capture and storage, initiatives towards energy reduction, waste heat recovery and alternative energy use. An analysis and quantification of the potential GHG reduction of potential carbon sinks and sequestration options for the mining and metal industry are provided. Cost estimates for different options are provided. The paper also identifies sources that could fund research regarding GHG reduction options. The paper concludes with recommendations.

Jan 1, 2011