ABSTRACT
As a potential alternative to cyanide with a low environmental footprint, the thiosulphate and thiourea leaching of precious metals from spent printed circuit boards and spent catalytic converters is the prime focus of this chapter. The complexation chemistry of metal–thiosulphate complexes and the mechanistic aspects, the impact of temperature, oxygen, ammonia, and copper along with other associated metal ions on thiosulphate leaching of precious metals from urban mine sources are explained in detail. Thiosulphate process limitations, challenges, and environmental impacts are also addressed.
