Correlation of adsorbed polymer layer properties with depressant performance

Abstract

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined, both through ex situ depletion techniques and in situ ATR-FTIR spectroscopy. Adsorbed layer thicknesses have been determined for the polymers on talc particles (using acoustophoresis), and on cleaved talc surfaces (using the AFM). The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and through single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.