Hydrometallurgy describes the aqueous chemistry, thermodynamics, kinetics, reactor design and engineering of extracting metals by hydrometallurgical routes. The book includes the techniques by which gold, copper, nickel, cobalt and the platinum-group metals are produced as highly-pure metals to meet the exact needs of the market. In addition, the book covers the scientific and engineering principles of these types of processes, the industrial practice used to produce such high-value metals, and the factors that make these processes so successful. Finally, the recovery of valuable metals through recycling of waste materials is discussed.