Mineral species as functions of pH and oxidation-reduction potentials, with special reference to the zone of oxidation and secondary enrichment of sulphide ore deposits

Abstract

A series of diagrams has been prepared showing some stability and solubility relations among lead, zinc, and copper minerals found in the zones of oxidation and secondary enrichment of sulphide ore deposits. The stability and solubility relations are expressed as functions of pH and oxidation-reduction potential. These diagrams show theoretical equilibrium relations, and are sufficiently similar to relations found in the natural system to imply that the synthetic approach may be useful in the interpretation of field relations. The diagrams suggest the existence of relationships not previously reported, and provide plausible explanations for some known phenomena. A definition of the boundary between the “zone of oxidation” and “zone of secondary enrichment” is proposed.