Separation of cobalt and lithium from mixed sulphate solution using Na-Cyanex 272

The paper embodies the solvent extraction behavior of cobalt and lithium from mixed sulphate solution using Na-Cyanex 272 as an extractant. The effect of different parameters such as pH of feed solution, extractant concentration, cobalt and lithium ion concentrations in the feed solution and stripping behavior using different mineral acids such as H2SO4, HC1, HNO3 have been studied. The highest separation factor of 62 was obtained with 0.03 M Na-Cyanex 272 at an equilibrium pH of 6.90 from mixed solution of 0.01 M cobalt and lithium sulphate. About 84% of cobalt was extracted with a minimum of 8% lithium co-extraction at this condition. Cobalt was extracted as [CoA(2) - 3HA](org) with 65% Na-Cyanex 272. 2 mol of Na-Cyanex 272 are required for the extraction of I mol of cobalt. A complete stripping of cobalt can be achieved from the loaded organic with 0.01 M sulfuric acid solution. Cobalt sulphate solution with >99% purity can be obtained. (C) 2006 Elsevier B.V. All rights reserved.