On using electrokinetics to interpret the flotation and interfacial behavior of manganese dioxide

Abstract

The point of zero charge of manganese dioxide plays an important role in its flotation with physisorbing but not with chemisorbing collectors. Detailed flotation studies with oleate as the collector indicate two flotation and adsorption peaks in this system. The peak at low pH's appears to result from physisorption of oleate ions together with coadsorption of oleic acid molecules on the positively charged solid. At alkaline pH's, there is a second adsorption peak which must result from strong chemical interaction of oleate with the negatively charged surface. Electrokinetic experiments clearly indicate that oleate ions are the active collector species at both peaks. A procedure is proposed for estimating collector adsorption from electrokinetic data.