Processing of copper electrorefining anode slime: a review

Anode slime is the insoluble product deposited at the bottom of the electrorefining tank during electrorefining of copper. It generally contains Cu, Ni, Se, Te, Ag, Au, platinum group metals (PGM), Pb, Ba, Fe, etc. Owing to the presence of valuable metals and metalloids in the anode slime, numerous approaches have been made by the researchers to extract them following pyro-, pyrohydro-, hydropyro-, hydrometallurgical, etc. routes. In the present paper the various processing routes with the special emphasis on plant practice and precious metals recovery from anode slime have been described systematically. Since the understanding of the process chemistry is considerably aided by the formation and characterisation studies of the slime, these aspects have also been included.