E-waste recycling: An overview of hydrometallurgical processes used for metal recovery

Exponential population growth resulted in exponential demands for metals, especially for production of electronic devices, which are mainly sent to landfills at the end of their functional life. This practice poses a significant environmental hazard due to the presence of metals within these discarded materials, termed electronic waste or e-waste, which necessitate appropriate management strategies to avert adverse effects on both the ecosystem and human health. E-waste contains valuable metals often in concentrations rendering their recovery economically viable. Furthermore, the escalating demand for metals, driven by technological progress, has made the recycling of e-waste a crucial element of sustainable resource management. This work provides an overview of hydrometallurgical processing techniques for the recovery of valuable metals from the waste from electrical and electronic equipment, where hydrometallurgy plays a determinant role in the recovery of valuable metals such as copper, gold, and silver. These methodologies employ aqueous chemistry to facilitate the metal extraction, presenting a cost-effective and environmentally sustainable alternative when compared to production of metals by conventional mining practices. However, the economic viability of these alternative processes may fluctuate based on the specific type and concentration of metals present within the waste.