Abstract:The reaction process for leaching gold from sulfide gold concentrates containing copper with ammonia-ammonium thiosulfate solution containing copper(Ⅱ)can be divided into initial stage and later stage of reaction.Initial stage of reaction is controlled by interface reaction.Lat- er stage of reaction is controlled by diffusion process of reaction through solid products layer. Whole leaching process is under the control of corrosion reaction of pyrite bearing gold.Action of ammonium sulfate in the system is probably as follows:(1)NH₄⁺ and NH₃ forms a buffer so- lution;(2)SO₄~(2-)ion inhibites the oxidation and decomposition of S₂O₃ ~(2-)ion.Cu~(2+)ion in the system acts as an oxidant and oxygen makes the Cu~(2-)regenerate.

Key words: thiosulfate; gold; leaching kinetics; sulfide ore