Wetting behavior of molybdenite and talc in lignosulphonate/MIBC solutions and their separation by flotation

Flotation characteristics of molybdenite and talc are controlled by surface properties of their cleavage planes. Because the inherent hydrophobicity is common to the cleavage planes of both of these minerals, their separation by flotation is relatively more difficult compared to other mineral separation systems. Wettabilities of molybdenite and talc samples in sodium lignosulphonate/MlBC solutions have been investigated using both cleavage and disc specimens at a pH of about 7.2. The variation of adhesion tension, gamma (1v) cos theta with interfacial tension, gamma (1v), was found to be linear. The slope value, beta for each case has been utilized as an indicator of relative adsorption densities. This approach has indicated that the adsorption density of sodium lignosulphonate at the solid/liquid interface of molybdenite face was significantly larger than that of talc by a factor of 2.7. The difference in adsorption densities/wettability has been exploited to demonstrate highly efficient separation of these minerals in this surfactant system. The results of current investigation are consistent with the industrial practice of talc-molybdenite separation and provide some insight into the mechanism of depression behavior of molydenite.