Integrated technology for recovering Au from waste memory module by chlorination process: Selective leaching, extraction, and distillation

Abstract

Waste Memory Modules (WMMs), a particular kind of waste printed circuit boards (WPCBs), contain a large amount of precious metals like gold, which drives crude processes to retrieve gold with serious adverse consequences to the environment and human health, demanding innovative strategies to solve this problem. A safe and efficient technology for recovering gold from WMMs is proposed: firstly, selective leaching of gold and other metals by controlling the redox potential of the solution; then, producing sponge gold by extraction-distillation-calcination process. The results showed that the removing rate of copper was 96.5% under the conditions: reaction temperature of 80 °C, reaction period of 8 h, and redox potential of 0.4±0.01V; the leaching rate of gold reached 92.85% under the conditions: reaction temperature 50 °C, reaction period of 80 min, redox potential of 1.1V, and 17 g/L sodium chloride concentration; the extraction rate of gold was 95% when the volume ratio between organic phase and aqueous phase was 0.3; finally, the sponge gold with purity of 99.747% was produced via the courses of distillation and calcination. On the basis of these results, a sustainable continuous strategy to recycle gold from WMMs is put forward, providing an efficient and promising method for precious metals recovery from e-waste.