电镍含钴渣萃取分离钴的研究

EXTRACTION AND SEPARATION OF COBALT FROM LEACHING SOLUTION OF ELECTROLYSIS NICKEL SEDIMENT BY ALKYLPHOSPHONIC ACID MONOESTER

以电镍含钴渣为原料，通过酸溶浸出，氧化还原除铜、铁矾除铁及氟化盐除碱土金属工序得到含高镍低钴混合料液；研究了采用２－乙基己基膦酸２－乙基己基酯萃取剂对钴、镍的萃取性能和分离系数的影响；探讨了钴、镍萃合物的电子光谱，并对所得到的固体萃合物的热性质进行测定，说明在不同萃取温度条件下，利用钴、镍萃合物的不同构型，在工艺上能有效地提高钴、镍的分离效率；对负载钴、镍有机相采用洗涤、反萃工艺，可使萃取余液中的钴、镍比达３００以上．

A raw solution containing cobalt,nickel and other metal ions was obtained by leaching electrolysis nickel sediment with sulforic acid.Copper,iron and alkaline earth metal ions were removed from the solution by precipitation method.The solution containing a large amount of nickel and a small amount of cobalt(Ni/Co ratio up to 5∶1) were treated by solvent extraction with organic phosphonic ester in kerosene.The effect of 2 ethylhexyl phosphonic acid mono 2 ethylhexyl ester (HEHEHP) on the extraction and separation of cobalt and nickel was investigated.The extracted compounds were studied by electronic spectroscopy in kerosene and thermal analysis in solid state.On the basis of the measurements,it was found that the extracted compounds of cobalt were in different structures as temperature ranged from 25 ℃ to 50 ℃.The separation ratio of cobalt and nickel in the raffinate was up to 300 by the process of extracting the raw solution,scrubbing and stripping loaded organic phase which contained cobalt and nickel ions.