双萃取剂浸渍树脂色层分离硫酸体系中镍钴的研究

Separation of Nickel and Cobalt by Extraction Chromatography in Sulfuric Acid System

目前分离镍钴最主要的方法是溶剂萃取法,但是对于高镍低钴溶液,溶剂萃取法不能取得高效而经济的分离效果。研究采用HZ818苯乙烯二乙烯基苯大孔树脂和P507,Cyanex 272萃取剂自制双萃取剂浸渍树脂,利用萃取剂的协同作用和树脂色层萃取的高分离级数分离硫酸体系中的Ni^(2+)和Co^(2+),考察了树脂的萃取容量、萃取温度、萃取pH值、淋洗温度、淋洗pH值以及淋洗速度等因素对镍钴分离效果的影响。研究表明:在Φ20 mm×200 mm的色层柱中,选用一定浓度的HAc-NaAc作为缓冲体系,控制料液pH值为4.8,以5.0 ml·min^(-1)的进料流速能取得较好的吸附效果;控制温度为28℃,淋洗流速为5.0 ml·min^(-1),用pH为4.0的HAc-NaAc缓冲溶液淋洗Ni^(2+),当淋出体积为200 ml时,改用pH 1.0的硫酸淋洗Co^(2+),并收集淋出液,得到净化的硫酸钴溶液。

The main method for separating cobalt and nickel is solvent extraction,but with this method it is difficult to achieve efficient and economical effect for high nickel and low cobalt solution. Ni^（2＋）and Co^（2＋）in sulfate system were separated by the solvent impregnating resin which wassynthesized from HZ818 type of ethylene benzene-divinylbenzene porous adsorption resin,P507 and Cyanex272 extractant,and the resin had synergy and high separation series at the same time. The effects of extractive content of resin,extraction temperature,extraction pH value,elution temperature,elution pH value,and elution speed on the separation of nickel and cobalt were studied. The results indicated that the better absorption efficiency could be got when buffer system was HAc-NaAc,feed liquid pH value was 4. 8,current velocity of feed liquid was 5. 0 ml·min（-1）in Φ20 mm × 200 mm chromatography column. Ni（2＋）and Co（2＋）were separated when temperature was 28 ℃,elution speed was 5. 0 ml·min（-1）,buffer elution pH value of 4. 0. After eluting Co（2＋）by hydrochloric acid with pH of 1. 0 when eluting volume was 200 ml and collecting cobalt sulphate solution,the purified cobalt sulphate solution was obtained.