Abstract
Some critical interfacial properties of talc and its behavior in aqueous suspension have been studied in relationship to mineral processing, where reagent talc and four kinds of talc ore were used.
The pH of talc suspension with time was measured, and the results showed that the equilibrium pH of talc suspension was 7.5-7.9, but the value was slightly higher with talc accompanying dolomite and magnesite. As the initial pH of the suspension was lowered, the amounts of dissolved calcium and magnesium increased. With ore accompanying dolomite and magnesite, the amounts became very large, 3×10-3kmol/m3, when initial pH was 2. The isoelectric point of talc was found to be a pH of about 2.8. The coagulation phenomena were closely related to the zeta potential value, and the coagulation occurred below 10-15mV of the absolute value. With sodium carboxymethyl cellulose (CMC), the zeta potential values became extremely more negative. Flotation recovery of talc with methyl isobutyl carbinol (MIBC) alone and din-butylamine alone was high over the whole pH region, respectively. The adsorption of dodecylammonium acetate (DAA) on the talc surface was mainly electrostatic, and below pH 8 the recovery of talc with DAA alone was high. By CMC addition the recovery with MIBC was reduced to 10% or less
