Copper, Nickel, and Cobalt Production: Impurity Control and Removal

摘要

An ongoing challenge in the smelting and refining of copper, nickel, and cobalt has been to produce high-purity metals from a diverse range of concentrates containing various impurities at different concentration levels. This purification challenge has been met by using pyro-, hydro-, and electrometallurgy either individually or in combination. In pyrometallurgy, the removal of impurities-invariably to a slag phase for discard-is limited by equilibrium conditions; in hydrometallurgy, impurities are removed by precipitation, ion exchange (IX), and solvent extraction (SX). The precipitation step produces a residue for disposal in an environmentally acceptable manner, while IX and SX enable the possible recovery of the impurity metal either as a metal or salt. In electrometallurgy-both electrorefining and electro winning-the treatment of a bleed stream results in the removal of the impurities either as a product or residue thereby providing control of the same in the main circuit.