ABSTRACT
Precious metals are increasingly being used in many industries. Limited natural resources, increasing demand, and the associated economic value make it essential to efficiently extract precious metals from urban mine sources. During the last decade, rapid global technological development and the strict implementation of environmental legislation have led to the increased production of electronic and catalytic waste, presenting both challenges and opportunities in recycling for value-added precious metals. This chapter describes halide leaching of precious metals from urban mine sources such as spent printed circuit boards and catalytic converters. The coordination complexes of various precious metals with halide-based lixiviant, plausible mechanistic routes, process thermodynamics, and kinetic aspects are discussed in detail. The results of leach tests and the influence of various process parameters are explained. The limitations and challenges of halide leaching are reviewed.
