Abstract:Address to complex extraction process and a large number of extraction stages of cobalt extraction by step extraction method, P204+P507 was applied as complex extraction agent to separate Zn2+, Ca2+, Mn2+, Cu2+ from the industrial cobalt sulfate leaching solution in one time. Effects of equilibrium pH value, ratio of complex extractant, extraction phase ratio O/A, and saponification rate of organic phase on the extraction rate of elements were investigated. The results show that with 28%P204+7%P507 as complex extractant and 65% solvent oil as diluent, the saponification rate of organic phase is 50%, extraction equilibrium pH=3.57, and O/A=2, the single stage extraction rate of Zn2+, Ca2+, Mn2+ and Cu2+ is 99.97%, 94.65%, 88.42% and 87.18%, respectively, while extraction rate of Co2+ is only 17.42%. 99% of cobalt can be washed after two times washing by 1.5 mol/L sulfuric acid with stripping ratio O/A=20.