EARTHポスター発表（Poster：EARTH）

[PE1-040] Recovery of silver by hydrometallurgical process from electrode scraps

○Jaewoo Ahn¹, Yeon-Chul Cho¹, Hong-il So¹, Joo-Eun Lee¹ (1. Daejin University)

キーワード：Silver, Recovery, Solvent extraction, Electrowinning

Solvent extraction and cyclone electrolysis were used to recover silver from the nitric acid leach solution of electrode scraps. In order to investigate the extraction behavior of silver by Cyanex 301 in nitric acid leaching solution, the effect of nitric acid concentration, extractant concentration and the phase ratio(A/O) was examined. Above 99% of silver was extracted efficiently from the 3.0 M nitric acid leaching solution by two stages at 1.0 of phase ratio(A/O) using 5% Cyanex 301. Some co-extracted impurities were effectively removed by hydrochloric acid solution of 4.0 M or less. A pure silver solution was obtained from the loaded extractant by using a mixed solution of thiourea and hydrochloric acid as a stripping agent. In order to recover silver as an electrodeposited precipitates from the stripping solution, modified cyclone type electrowinning methode was adapted. From the experimental result, more than 99% of electrodeposited silver metal was obtained as a powdery form at a flow rate of 12 L/min., current density of 0.75 A/dm² and 35 ℃ for 6 hours in the 0.5 M Thiourea and 0.1 M HCl mixed solution.