Biohydrometallurgical processes for the recovery of precious and base metals from waste electrical and electronic equipments: Current trends and perspectives

Abstract

The acceleration in technological and economic development in the 21st century has fuelled a rise in electrical and electronic equipment (EEE) production and its use, which combined with the short life span of such devices and a high demand for cutting edge electronics, has increased the disposal of such devices. Such EEE contains highly toxic compounds that can damage the environment, but also highly valuable materials such as base and precious metals that can be recovered. Nevertheless, only 20% of waste EEE (WEEE) was recycled in recent years, a number that shows the need for further research on technologies in the field of WEEE recycling. While pyrometallurgy and hydrometallurgy have been recycling alternatives to recover metals from WEEE, biohydrometallurgy, or bioleaching, constitutes a more eco-friendly and cost-effective option. This review presents the basic mechanisms of bioleaching, the current state of research on base and precious metals bioleaching from WEEE, the effect of process parameters on the bioleaching efficiency and challenges linked to the performance and scaling up of this technology.