Hydrometallurgy

Hydrometallurgy is a process of separating, concentrating, and extracting valuable metals from different raw materials (crude ore, concentrate, or roasted product), intermediate products, or secondary renewable resources through oxidation, reduction, neutralization, hydrolysis, replacement, and coordination reactions in aqueous solutions by use of the chemical actions of solvents. It is also called wet metallurgy as the process is mostly carried out in aqueous solutions. Hydrometallurgy and pyrometallurgy are two fundamental metallurgical processes, and both belong to chemical metallurgy or extractive metallurgy.

The basic steps of obtaining metals from ores by hydrometallurgy are as follows: (1) transfer of useful components from raw materials to the solution, namely, leaching, also called infiltration, infusion, dissolution, or wet decomposition. The leaching process is classified into water leaching, acid leaching, and alkaline leaching according to solvents; it can also be...