Cationic flotation of nonsulfide minerals

Abstract

From the analysis of information on flotation of quartz, barite, hematite and diamond spar using cationic reagents (amines), the authors show deficiency of thermodynamic approach to explain flotation results by one type of adsorption due to ion–electrostatic mechanism. The discussion offers hypothesis that says that at low pH collecting ability of a reagent is connected with hydrophobic attachment of the reagent ions in adsorption layer. In alkaline range of pH, the collecting ability is conditioned by formation and precipitation of ionomolecular associates in the adsorption layer of a mineral. These types of adsorption attach particle surface which is preliminarily made hydrophobic by ion–electrostatic mechanism. These adsorption types are active at bubble–liquid interface and can go to this interface upon rupture of water film between a particle and a bubble. According to the suggested hypothesis, liquid tension in the film becomes nonuniform and a surface force arises and expels kinematic constraint for particle–bubble attachment. The analytical review of the collected test data on cationic reagents proves the suggested hypothesis. The causes of breakdown of correlation between surface pressure and collecting ability for initial conditions of flotation are explained.