Dasmi Maharaj Dasmi Maharaj

Project Title: Exploration of the thiosulphate process for the dissolution of gold from electronic waste and its recovery via ion-exchange.

Research Theme: Value from Waste

Supervisors: Jochen Petersen and Thandazile Moyo

Abstract

E-waste is formed when electronic and electrical equipment reaches the end of its life with no use. It contains precious metals such as gold. Waste printed circuit boards (PCBs) are a small part of e-waste and contain a variety of metals thus PCBs have various advantages, if treated and recycled properly. This project incorporates both the extraction and recovery of gold from PCBs in alkaline system thus eliminating the need for other toxic processes utilised for gold extraction (cyanide leaching).

Pre-treatment (shredding/sawing) of the PCBs is required as the first step before extraction. Leaching experimentation will be conducted on gold powder to determine the kinetics and thermodynamics. Further experimentation involves changing parameters to investigate the gold concentration in solution. Experimentation on the gold from the leached solutions will also be investigated. Two different resin types (strong- and medium-base) are to be tested from standardised solutions containing gold powder. Loading of the resin will be conducted before elution. Two eluants will be utilised to determine the effect on gold recovery.Recovering gold from PCBs will prove to be vital in comparison to other ore processes thus playing a part in the circular economy through the recycling of e-waste.