Solvent extraction of Cu, Zn, Co from nickel sulphate solution applying P507

Fornickel sulfate solution after the removing of iron, arsenic, calcium and magnesium, sodium-saponified P507 extractant was used to separate copper, zinc, cobalt. The effects of saponification efficiency, P507 volume fraction, equilibrium pH, phase ratio, time, temperature and countercurrent extraction stage on extraction and separation were investigated. The effects of sulfuric acid concentration, stripping ratio and time on the recovery rate of copper, zinc and cobalt were also investigated. Experimental results showed that, with the extractant of 35 % P507 + 65 % sulfonated kerosene, the saponification rate of sodium of 65 %, the phase ratio of 1:1, the equilibrium pH of 4, the reaction temperature of 25 ℃ for 5min, the extraction rates of copper, zinc, cobalt after three-stage countercurrent extraction were 96.73 %, 99.87 % and 94.17 %, respectively. The loaded organic phase after extraction was washed with acidic deionized water (pH=3~4) and then stripping with 1mol/L sulfuric acid solution for 5 min under the stripping ratio (V_O/V_A)of 1: 1. Under these reaction conditions, the stripping rates of copper, zinc, and cobalt were 99.94 %, 99.94 % and 99.86 %, respectively.