The Adsorption of Sodium Cetyl Sulphate on Cassiterite

Abstract

The adsorption of sodium cetyl sulphate on pure synthetic cassiterite has been measured under various conditions of concentration and pH and the results related to flotation. It was found that only a small proportion of the surface need be covered with collector ions to make flotation possible. At high concentrations of collector no evidence was found of a double layer of collector ions on the mineral surface, and it is concluded that the cessation of flotation at these concentrations is due to " armouring " of the bubble surfaces. A mechanism for the adsorption of cetyl sulphate ions is proposed, in which these ion3 exchange with hydroxyl ions on the hydrated surface. An attempt is made to describe the ionic equilibria at the cassiterite surface. Samples of natural cassiterite differed from one another and from the synthetic mineral in their ability to be floated under certain conditions : this is attributed to the effect of metallic impurities.