Question

Describe the role of the following in the process mentioned.

Sodium cyanide in froth floatation.

Answer 1

Sodium cyanide acts as a depressing agent in the froth floatation process. It prevents other metal sulphides from coming to the froth.

eg: NaCN depresses the floatation property ZnS present in Galena (PbS) by forming a layer of Zinc complex Na₂[Zn(CN)₄] on the surface of Zinc sulphide.