As a fundamental study on the recovery of fine particles of valuable minerals by liquid-liquid extraction, the concentration of fine quartz particles (0.24 mum average diameter) at the oil-water interface in the absence of a surfactant collector has been investigated. Isooctane and water were used as the two liquid phases. The recovery percentage of the quartz fines was determined as a function of the concentration of an added electrolyte (sodium, calcium and lanthanum chloride) and the pH value of the aqueous suspension. Based upon electrokinetic measurements, the liquid-liquid extraction results are interpreted in terms of colloid stability theory. Calculations of the total potential energy of interaction between isooctane and quartz indicate that height of the primary potential energy peak, which acts as an energy barrier in the quartz-isooctane coagulation process, correlates closely with the collectorless liquid-liquid extraction recovery of the quartz fines.