Critical surface tension of wetting and of floatability of molybdenite and sulfur

Abstract

Molybdenite and sulfur samples have been used for adhesion tension determinations in aqueous methanol solutions. The critical surface tension of wetting, γ c, of the crystal faces of molybdenite and sulfur was found to be 29 and 27 mN/m, respectively. Both γ c and β, the slope of the adhesion tension line, increased as the polar nature of the sample increased. Polar characteristics of various specimens were estimated from the octane contact angle measurements. These were related to the β values of respective samples. The adhesion tension behavior of aqueous solutions of Syntex (a commercial surfactant consisting of sulfonated monolgycerides of coconut oil) on molybdenite was also studied and compared to that of methanol. A good correlation has been observed between wettability and floatability of the samples. The flotation test data have been employed to illustrate the effect of grinding on the critical surface tension distributions of molybdenite.