In 1997, a 24-tonne per annum gold refinery was commissioned at Harmony Gold Mine in South Africa making use of solvent-extraction technology to produce gold of 99.99% purity. Feed material for the refinery was cathode sludge arising from carbon-in-pulp/electrowinning circuits, zinc precipitate or atomised dore bullion. Following Harmony's purchase of a further five gold mines, a larger refinery capable of producing 70 tonnes per year of high-purity gold, has been installed. Implementation of this process results in significant cost benefits compared with conventional smelting/toll-refining. Any premiums on the sale of high-purity gold products are realised. Harmony has established its own brand name.
展开▼
