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摘要
Acid leach liquors from spent lithium-ion batteries that use lithium cobalt dioxide (LiCoO2) as a cathode active material contain valuable metals such as cobalt and lithium, as well as common metals such as aluminum and copper. The objective of this study was to develop a hydrometallurgical process that provides a degree of high selectivity between aluminum, cobalt, copper, and lithium from acidic sulfate media. %26lt;br%26gt;The results from batch experiments showed that a selective hydroxide precipitation approach was not suitable because a significant amount of cobalt was coprecipitated with aluminum and/or copper hydroxides. In contrast, batch experiments and the subsequent data analysis indicated that the sequence of solvent extraction circuits using PC-88A, Acorga M5640, and tri-n-octylamine (TOA) extractants effectively separates four metals of interest. In the first circuit of the proposed process, copper was selectively extracted by Acorga M5640 at pH 1.5-2.0. Aluminum, cobalt, and lithium remained in the aqueous phase. In the second circuit, aluminum was selectively extracted by PC-88A at pH 2.5-3.0. For separation of the remaining cobalt and lithium, Acorga M5640 provided higher cobalt selectivity (separation factor could not be accurately obtained due to negligible lithium extraction) compared to PC-88A (beta(Co. 90%/Li) = 350 at pH 4.5) and PC-88A/TOA (beta(Co. 90%/Li) = 1,170 at pH 5.4). However, the stripping efficiency of cobalt from the Acorga M5640 organic phase was found to be low (less than 10%). Therefore, the PC-88A/TOA mixed extractant rather than Acorga M5640 is a suitable choice for the separation of cobalt and lithium.
- 出版日期2012-9-19
