COLLECTORLESS LIQUID-LIQUID-EXTRACTION OF FINE MINERAL PARTICLES USING VARIOUS ORGANIC LIQUIDS AS THE OIL PHASE

As part of the fundamental studies on the recovery of fine mineral par ticles by liquid-liquid extraction, the transfer of fine quartz and ga lena particles from a water phase to an oil phase or to the oil-water interface was investigated in the absence of a surfactant collector. V arious organic liquids of paraffin, aromatic hydrocarbons, ether, keto ne, and higher alcohols were test oils. High recoveries of the galena particles were obtained using comparatively low polar liquids, while t he recovery of quartz was impossible using any organic liquids. Calcul ations of the wetting property, the work of adhesion, of these solid s urfaces with the liquids, based upon contact-angle measurement and the liquid surface free energy, indicated that the wetting on the quartz surface with water was most likely to occur, while the wettabilities o f the two solids with the organic liquids were comparable. In addition , a thermodynamic criterion of collectorless liquid-liquid extraction were discussed in terms of the surface free energy change in the oil-w ater-solid, three-phase system during the oil-to-solid adhesion in wat er.