Cyanex 272萃取分离硫酸钴溶液中镍钴的试验研究

采用Cyanex 272萃取剂从硫酸钴溶液中分离去除镍,在有机相组成为25%Cyanex 272+75%航空煤油(用30%NaOH皂化,皂化率75%)、萃原液pH值4.5～5.0、温度25～35 ℃、相比1.5～2条件下,经5级逆流萃取,混合萃取时间5 min,然后用1 mol/L硫酸溶液4级反萃取获得反萃取液,钴直收率达99.86%,Ni去除率达95.20%,钴镍分离效果较好。反萃取后的硫酸钴溶液中杂质含量很低,Co/Ni比达368 95,可以满足生产精制CoSO₄·7H₂O和电钴的要求。

Extraction of Nickel and Cobalt from Cobalt Sulphate Solution with Cyanex 272

Extractant of Cyanex 272 was adopted for removing nickel from cobalt sulfate solution by separation. With the organic phase consisting of 25% Cyanex 272 and 75% aviation kerosene (saponification with 30% NaOH, saponification rate at 75%), pH value of extraction solution at 4.5～5.0, temperature at 25~35 ℃ and phase ratio(O/A) at 1.5~2, the cobalt sulfate solution went through 5-stage counter-current extraction for 5 min, followed by a 4-stage back extraction with 1 mol/L sulfuric acid solution, resulting in the stripping solution with the direct yield of cobalt at 99.86% and nickel removal rate at 95.20%, indicating a good separation of cobalt and nickel. It is shown that the cobalt sulfate solution after back extraction, with very low content of impurities and Co/Ni ratio at 36 895, can meet the requirement for the production of refined CoSO₄·7H₂O and electrolytic cobalt.