Hydrometallurgy for nano-scientists

Abstract

Hydrometallurgy is a relatively recent subject. Major hydrometallurgical processes started at the end of the 19th century for the leaching of gold ores using a cyanide solution and for leaching of bauxite by sodium hydroxide to get pure aluminum oxide for the expanding aluminum industry. At the beginning of the 20th century leaching of low grade copper oxide ore and leaching of zinc oxide calcites by dilute sulfuric acid were introduced on large scale. It was, however, during World War II that new hydrometallurgical techniques such as ion exchange and solvent extraction were developed for the recovery of uranium for the manufacture of atomic bombs. These new technologies as well as others revolutionized hyfrometallurgy. Hydrometallurgical processes are now competing with the ancient pyrometallurgical routes.