Hydrometallurgy is a field of chemical technology concerned with the production of metals from their ores and secondary sources. Modern hydrometallurgy began with the need to obtain uranium in the 1940s and extended into new areas with the development of pressure hydrometallurgy in the mid-1950s and acceptance of solvent extraction as an industrial scale process for copper production in the late 1960s to early 1970s. With the introduction of new processes for many metals, the present stage of development of hydrometallurgy has come to maturity and a survey of the current state of the field is...