The liquid-liquid extraction of copper (II) by mixtures containing tri-n-octyl phosphine oxide (TOPO) and lauric acid (LA) was studied. The effects of the concentration of the extracting agent in the organic phase and KCl in the water phase were investigated. The comparison between the results of extraction tests obtained with each separate extracting agent and those obtained with their mixtures, showed a synergistic effect. Yield of 100% in a single stage was attained in the cases of mixture. The ratio TOPO/LA in the complex in cyclohexane solution was determinated as 1: 1. The complex formed in the organic phase may be (CuCl)2 TOPO (LA-H)2. The coordination bonds of the Cu-complex were determined by infrared spectroscopy.
