Urban Mining of Precious Metals with Cyanide as Lixiviant

This chapter is devoted to investigations and developments in precious metal leaching from urban mines using cyanide as lixiviant. Factors affecting platinum, palladium, gold, and rhodium leaching are the characteristics of the particular reagent and process chemistry. Extraction mechanisms are discussed in depth. The cyanide leaching order of platinum, palladium, and rhodium, and its correlation with metal bonding strength, is also explained. Additionally, this chapter reviews the feasibility of biogenic cyanidation of precious metals, process fundamentals, the microbial biogenic cyanidation pathway, and its potential as a chemical cyanide alternative. The limitations and challenges, as well as the environmental footprint of the process, are reviewed comprehensively.