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( Minsoo Kim ),( Sanghyuk Han ),( Jiwoong Jeon ),( Sangwoon Woo ),( Jun Won Yang ),( Sungyoon Park ),( Yejee Lim ),( Nway Oo Khin ),( Jimin Yu ),( Han S. Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-
To date, demand for valuable metals continuously increasing due to electronic industries in Korea, and as a result, the generation of wastes are dramatically increasing. Along with aluminum, copper is one of the most demanding metals in most industries, and therefore, their recovery and recycling have received extensive interests. High-purity copper is critically required for electronic and electrical industries. A number of purification processes have been developed for the purity level-up of low-degree copper recycling resources. In this study, copper was recovered from acidic wastewaters generated in plating processes by electrolysis. Copper extraction was conducted in a 1.5L batch type reactor (90×120×170 mm, L×W×H) made of plexiglass. Cathode was made of a stainless-steel plate and anode was prepared by coating iridium/ruthenium onto a titanium plate (100×100×0.4 mm, L×W×T for both electrodes). The electronic wastewaters used in this study were highly acidic (mainly composed of sulfuric and nitric acids, respectively) and contained a considerable amount of copper. The metals contained in the sulfuric acid wastewater were 92.95% of copper, 2.89% of iron, 1.19% of lead, and 2.97% of other trace metals and those in the nitric acid wastewater were 49.87% of aluminum, 45.97% of copper, and 4.16% of other trace metals. Inductively coupled plasma-optical emission spectroscopy was used to determine the recovery rate and purity of copper during electrolysis. Recovery rate of copper from sulfuric acid wastewater and its purity were 99.98% and 99.47%, respectively. Recovered copper was obtained in the form of thin foil at the high recovery rate. Furthermore, it was found that the recovery rate of copper from the sulfuric acid wastewater can be effectively enhanced by optimizing reaction run time, current density, and chemical additives. On the contrary, copper in nitric acid wastewater was not recovered by electrolysis. Instead, a precipitation method was employed for the recovery, and 86.54% of recovery rate was achieved as a copper hydroxide form. This copper can be recovered by dissolving into sulfuric acid wastewater followed by electrolysis process. Voltage and temperature did not change significantly, and the pH was maintained at the low level due to the H+ formation in the electrolysis process. The results of this study will be useful for the development of a process that efficiently recovers high purity copper from waste acids and wastewaters of plating process.