Leaching of Silver (Ag) from Electronic Scrap by Thiourea

Abstract

In order to apply the silver cementation method using Fe powder from pregnant thiourea leaching solution. Parameters such as the amount of Fe powder addition, agitation speed, and temperature were investigated. The silver cementation rate was increased by the increasing of Fe powder addition, agitation speed, and temperature. The highest silver cementation rate was found when the addition of Fe powder was 50 g/L at the agitation speed of 500 rpm. The silver cementation rate increase with increasing temperature according to the Arrhenius equation and obeys 1 st order kinetics. The activation energy from the kinetics data was found to be between 13.73 KJ/mol and 17.02 KJ/mol. In the XRD analysis, goethite was detected in the precipitate of the thiourea leach solution. This indicates that an oxidation-reduction reaction had occurred in the thiourea solution due to the addition of the Fe powder.

Improvement of Alumina Dissolution from the Mechanically Activated Dross Using Ultrasound-Assisted Leaching

“…In the hydrometallurgical process, alumina and other oxides are dissolved from the black dross by employing either acid or alkaline solutions [2][3][4]. Alkaline leaching offers the selective leaching of alumina over other oxides from black dross, but the leaching percentage of alumina is generally low [4,5]. In order to improve the leaching percentage of alumina without affecting the purity in the leaching solution, the choice of chemicals and the selection of effective methods are key to developing a new process.…”