
TY  - JOUR
A1  - Filmer, AO 
A1  - Parker, AJ 
A1  - Wadley, LGB 
T1  - Oxidation of Copper Sulfides in Aqueous Ammonia. I. Formation of Sulfur
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1979
VL  - 32
IS  - 5
SP  - 961
EP  - 973
KW  - 
UR  - https://doi.org/10.1071/CH9790961 
N2  - Elemental sulfur, rather than sulfate or thiosulfate ions, is the major sulfur-containing product when CuS or Cu2S are oxidized at temperatures below 40º with oxygen in a large excess of aqueous ammonia containing ammonium sulfate at pH 10-10.5. At temperatures above 60º, or in solutions containing low proportions of ammonia or ammonium sulfate, very little sulfur is formed. Higher partial pressures of oxygen lead to higher proportions of sulfur. These observations are explained in terms of concurrent and consecutive reactions involving copper polysulfides. The high proportion of ammonia to soluble copper ions which is required imposes some practical limitations on any potential leaching process aimed at producing sulfur. Proportions of sulfur from metal sulfide oxidation in aqueous ammonia decrease in the series of metal sulfides, Cu2S > CuS > NiS > FeS > ZnS > CoS. Some aspects of the chemistry of sulfur in aqueous ammonia are discussed. 
ER  -

