Co-extraction of Mn2+, Co2+, and a part of Ni2+ from sulfuric acid solution containing Li+ using the new ionic liquids

Abstract

In this study, five novel ionic liquids denoted by [RNH3][Cyanex 272] where R = C4H9, C6H13, C8H17, C10H21, and C12H25 were synthesized in a one-step reaction of straight-chain primary amines and Cyanex 272. The singe-stage extraction performance of [RNH3][Cyanex 272] for the separation of Mn2+, Co2+, Ni2+ and Li+ was investigated. Compared with the other [RNH3][Cyanex 272], the [C4H9NH3][Cyanex 272] has good selective extraction and separation of Mn2+, Co2+, and Ni2+ due to the smaller different value between the radius of metal ion and the radius of [C4H9NH3]+. Using a three-stage cross flow extraction, the extraction percentages of Mn2+, Co2+, Ni2+, and Li+ were about 99.4, 99.1, 14.9 and 0.9 %. The [C4H9NH3][Cyanex 272] is a good extraction agent for co-extraction of Mn2+, Co2+, and a part of Ni2+ from Li+ based on a three-stage cross flow extraction. Diluted sulfuric acid was used to strip the organic phase containing Mn2+, Co2+, and Ni2+, and the aqueous phase containing Mn2+, Co2+, and Ni2+ can be used for the preparation of ternary precursor materials. The precipitation method can be used to prepare Ni(OH)2 and Li2CO3 from an aqueous phase containing Ni2+ and Li+. The conceptual recycling flow-sheet for Mn2+, Co2+, Ni2+, and Li+ from spent ternary lithium batteries was presented on basis of the new extraction agent. The slope method was also used to investigate the mechanism of the extractive reaction of Mn2+, Co2+, and Ni2+ using the [C4H9NH3][Cyanex 272].