Abstract:Distribution ratio (D) and separation coefficient (β) of mixed rare earth and aluminum in naphthenic acid system were studied under different acidity of mixed light rare earth materials, aluminum concentration and different saponification values of extractant. The results show that when pH value of the mixed rare earth solution is 0.5, DAl=16, DRE=0.044 8, and βAl/RE=356.9; when Al2O3 concentration in solution is 0.17~0.32 g/L, DAl>1, and βAl/RE exist biger value; when degree of saponification is 0.3 mol/L, not only emulsification caused by oversaponification can be avoided, but also rare earth and aluminum have better separation effect. Therefore, separation effect and higher separation factor of aluminum and mixed rare earth can be obtained in naphthenic acid system with high acidity, low aluminum concentration and low degree of saponification. Organic phase and aqueous phase are easier to stratify, and extraction reaction interface is basically free of three phases under the optimum separation and extraction experiments conditions. Aluminum content in remaining liquid is less than 0.011%, which satisfies requirements for aluminum content in industrial production.