E-wastes derived sustainable Cu recovery using solvent extraction and electrowinning followed by thiosulfate-based gold and silver extraction

Abstract

The sustainable extraction of copper from electronic wastes was investigated using a bioleaching process followed by solvent extraction (SX) and electrowinning (EW). Specific extractant and diluent for selective copper recovery from leach solution, were used. In order to examine how processing parameters affect the extraction coefficient and improve loading/stripping efficiency, the separation factor was analyzed. After SX, electrowinning (EW) was performed using stainless steel blanks and inert anodes. To achieve the best operating conditions and minimize energy consumption, a copper EW model that simulates industrial processing was developed using empirical equations and established fundamental electrode kinetics. Because of its high effectiveness and low cost, cyanide has been frequently utilized in the extraction of gold. But, in this work, thiosulfate leaching-based which is ecologically friendly procedure was established for gold extraction. The effects of concentrations of the reagents such as thiosulfate, copper (II), and ammonia on the leaching of gold/silver were investigated. A response surface methodology modeling of the leaching process based on central composite design was used to optimize the processing parameters. The ideal conditions for gold leaching from PCBs were discovered, and utilizing electrowinning, the gold recovery from the pregnant thiosulfate solution was also examined.