Copper transport and sulphide sequestration during copper corrosion in anaerobic aqueous sulphide solutions

The corrosion of copper in aqueous solutions containing ≥5 × 10−4 mol/L sulphide and the ensuing accumulation of corrosion product deposits (as chalcocite Cu2S) occurs non-uniformly indicating the occurrence of microgalvanic coupling between net anodic and net cathodic surface locations. A series of novel electrochemical experiments were designed to confirm the occurrence of this process and a series of analytical procedures used to identify the chemical nature of the transported Cu species. Transport was found to occur as copper sulphide complexes and clusters. It was also demonstrated that all the available sulphide was sequestered as deposited Cu2S.