Zinc Oxide

Zinc oxide material reacts with sulphides to form Zinc Sulphide, ZnS under normal operating conditions. This precipitate is an insoluble, inert, fine solid which remains harmlessly in the mud system or is removed by the solids control equipment. Zinc oxide is effective at the pH levels found in drilling fluids. It is recommended that a pH above 11 be maintained whenever H2S is expected. This high alkalinity converts the dangerous H2S gas to less toxic disulphide (HS-) and sulphide (S2-) ions. The alkaline pH >11 allows an extra margin of safety.