Journal of Sustainable Metallurgy | 2021
Recovery of Lithium from Brine with a High Mg/Li Ratio Using Hydroxyl-Functionalized Ionic Liquid and Tri-n-butyl Phosphate
Abstract
Abstract In this study, a hydroxyl-functionalized ionic liquid 1-hydroxyethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide ([OHEMIM][NTf 2 ]) and tri- n -butyl phosphate (TBP) were used as co-extraction reagent and extractant, respectively, to improve the extraction efficiency of Li + and the separation factor of Li–Mg from brine with a high Mg/Li ratio. The extraction efficiency of Li + is 94.2% and the separation factor of Li–Mg is 539 under the optimal condition. The washing efficiency of Mg 2+ and K + is close to 100% using 0.6\xa0mol L −1 LiCl and 1.8\xa0mol L −1 NaCl as the washing solution at an organic-to-aqueous phase ratio ( O / A ) of 4, and the stripping efficiency of Li + is about 98.0% using 1.0\xa0mol L −1 HCl as the stripping agent at an O / A phase ratio of 1. The extraction efficiency of Li + is reduced by less than 4.4% after seven cycles, indicating that the extraction system is stable and reusable. Graphical Abstract