• Resources Recycling
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• v.21 no.1
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• pp.3-16
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• 2012

In order to review the technological modulus of the recycling of urban mine resources and non-ferrous smelting process in Korea, key point of recycling process, physical separation, non-ferrous smelting process, unit operation for the recycling technology, recycling process of LS-Nikko Copper and Korea Zinc were studied. Finally, metal recycling processes of the typical non-ferrous smelters in Japan such sa DOWA Holdings and JX Holdings were compared with those of LS-Nikko Copper and Korea Zinc.

• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.223-228
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• 2006

The current efficiency of copper anode containing impurities in copper sulfate solution for electrorefining was studied at various current type such as direct current, variable current and periodic reverse current. The passivity behavior was investigated by galvanostatic technique. The results obtained were that current efficiency of variable current was higher than those of direct current and periodic reverse current. The increased current efficiency could be explained by the formation of slime structure with lower average resistance due to variable current. The frequency of various factors in variable current condition has a greatest effect on current efficiency. It appeared that frequency increased current efficiency when increased from 1 to 4, but further increases did not have an effect.

• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.215-222
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• 2006

The passivity behavior of copper anode containing impurities in copper sulfate solution for electrorefining process was studied at several different levels of impurities such as As, Sb, Bi and Pb. The passivity behavior was investigated by electrochemical techniques (galvanostatic, potentiodynamic and cyclic voltammetry tests) and surface analysis (optical microscopy, electron probe microanalysis, scanning electron microscopy). The results were that arsenic, antimony inhibited passivation and bismuth accelerated it and lead containing anode showed different passivity behavior from above anodes. The improved passivity characteristics could be explained by decrease in oxygen content in passivity film which resulted from a reaction among the impurities, oxygen and copper in the anode. The SEM image revealed that arsenic or antimony containing anode exhibited a porous passivity film and bismuth containing anode showed the compact passivity film and lead containing anode had loose passivity film on anode.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1370-1376
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• 2010

In this study, usability and stability in the caisson filling material were reviewed that copper salg(one million tons per one-year) were produced by smelter. In order to complete these studies, chemical and physical comparing analyses were performed by sea-sand materials as to the materials suitability, After construction, the structural displacement of caisson was measured by the instrument and was examined for stability. As a result of analysis, it was determined that copper slag is eco-friendly, and can be used as recycled alternative to aggregates materials.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.1
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• pp.29-33
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• 2011

The current density in copper electroplating is directly related with the productivity and then to increase the productivity, the increase in current density is required. To obtain the high mass flow rate, rotating disk electrode(RDE) was employed. High rotational speed in RDE can increase the mass flow rate and then high speed electroplating was possible using RDE to control mass flow. Two types of cathode were used. One is RDE and another is rotating cylindrical electrode(RCE). A constant-current, constant-voltage and linear sweep voltammetry were applied to investigate current and voltage relationship. The maximum current density without evolution of hydrogen gas was increased with rotational speed. Over 400 rpm, maximum current density was higher than 1000 A/$m^2$. The diffusion coefficients of copper calculated from the slope of the plots are $5.5{\times}10^6\;cm^2\;s^{-1}$ at $25^{\circ}C$ and $10.5{\times}10^6\;cm^2\;s^{-1}$ at $62^{\circ}C$. The stable voltage without evolution of hydrogen gas was -0.05 V(vs Ag/AgCl). Additives were added to prevent dendritic growth on cathode deposits. The surface roughness was analyzed with UV-Vis Spectrophotometer. The reflectance of the copper surface over 600 nm was measured and was related with the surface roughness. As the surface roughness improved, the reflectance was also increased.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.27-33
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• 2007

It is very important in the view point of resource recycling to recover valuable metals such as copper and tin from waste electric and electronic scrap. The waste electric and electronic scrap contains significant amounts of copper, tin, and so on. In this study, a new process for extracting copper and tin contained in the waste electric and electronic scrap using waste copper slag which is generated from the melting furnace of copper smelter was presented. Advantage of the proposed process is to reuse waste copper slag instead of new fluxes as slag formatives. In each experiment, the waste electric and electronic scrap and waste copper slag were melted inputting suitable amount of CaO as an additional flux. Up to 95% of copper and 85% of tin in the raw material were extracted in a Cu-Fe-Sn alloy phase.

• Resources Recycling
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• v.17 no.1
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• pp.51-58
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• 2008

Artificial mattes were prepared with adding pyrite or chalcopyrite as sulfur sources with Cu-Ni-Co-Fe alloy. The major phases identified by X-ray diffraction pattern were $(FeSi)_9S_8$, $CuFeS_2$, FeS, $Co_4S_3$, $Ni_3S_2$ and $Cu_2S$ for both mattes, and the matte prepared by adding chalcopyrite showed the higher peak of $Cu_2S$ due to high content of copper. Under optimum conditions, more than 95% copper, 90% nickel and 90% cobalt were extracted into leaching solution and sulfur concentration in the mattes did not much affect the leaching efficiency of the metals. The increase of the amount of pyrite or chalcopyrite added decreased pH in leaching solution and increased the concentration of iron ion dissolved in the leaching solution and the amount of residue.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.2
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• pp.43-48
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• 2011

The maximum current density of copper electrorefining is 350 A/$m^2$ and the higher current density is required to promote the copper productivity. The 1000 A/$m^2$ high current density is possible when rotating disc electrode is employed to reduce diffusion thickness. The copper electroplating with 1000 A/$m^2$ is possible at 400 rpm. Thiourea and glue were used to improve the electrodeposition behaviors during copper electrorefining process. Potentiodynamic polarization tests were conducted to investigate the effects of additives on copper electrodeposition. Galvanostatic tests were also conducted at 1000 A/$m^2$. Copper were electroplated on cylindrical rotating electrodes to give the uniform flow on the electrode surface. The lowest surface roughness was obtained when 16 ppm thiourea was added to the electrolytes. The surface roughness was increased with glue concentration. The surface hardness was not influenced by addition of glue. The copper nuclei were getting smaller with thiourea concentration, however there is no glue effects on copper nucleation.