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 particles by liquid-liquid extraction, the transfer of fine quartz and galena particles from a water phase to an oil phase or to the oil-water interface was investigated in the absence of a surfactant collector. Various organic liquids of paraffin, aromatic hydrocarbons, ether, ketone, and higher alcohols were test oils. High recoveries of the galena particles were obtained using comparatively low polar liquids, while the recovery of quartz was impossible using any organic liquids. Calculations of the wetting property, the work of adhesion, of these solid surfaces 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 of 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-water-solid, three-phase system during the oil-to-solid adhesion in water.