Current trends in gold recovery from electronic wastes

Electronic wastes (e-wastes) refer to abandoned electrical and electronic equipment (EEE). E-waste contains significant concentration of gold which is 10 times more than its concentration in gold ores. It approximately contains 10–10,000 g of gold/ton, whereas the gold ore contains barely 0.5–13.5 g of gold/ton. In this chapter, insights on the importance of precious metal recovery (PMR) from e-waste are emphasized. Also, an overview of various technologies available to recover precious metals from e-waste was presented and the hydrometallurgy process was emphasized in view of economic and environmental aspects. Hydrometallurgical techniques involving leaching and purification have been discussed by analyzing the pros and cons of potential leaching reagents such as cyanide, halide, thiourea, and thiosulfate. A useful discussion on current technological advancements in the field of PMR from e-waste is included to understand the progress made by industries and technologists. In addition, the future scope of PMR pertaining to the small-scale recovery of gold from low karatage gold jewelry and industrial scraps is provided.