Enhancing lithium stripping from the solvent extraction system of tributyl phosphate and FeCl3 using amines

 Lithium is an essential element in lithium-ion-batteries (LIBs) for electric vehicles and portable devices. Currently, the majority of global Li2CO3 is produced from salt lake brines, which contain over 70% of the exploitable lithium reserves. The existing hydrometallurgical processes for the separation of lithium from the associated magnesium in brines suffer from low recovery rate and create a heavy environmental burden. The synergistic solvent extraction (SX) system consisting of tri-butyl phosphate (TBP) and FeCl3 has a high lithium selectivity over magnesium and shows potential for developing a more sustainable process for lithium and magnesium separation. However, the stripping of lithium from the loaded organic phase is very difficult and consumes large amounts of acids. This project proposes a new strategy to enhance lithium stripping by regulating metal coordination in the organic phase. The improved new synergistic SX system will combine efficient lithium extraction, high lithium selectivity and easy stripping. In addition, all the chemicals used in the new SX system are commercially available in large scales at a low price, which ensures easy scaling-up of the process. The new synergistic SX system is expected to display potential for implementation in industry for sustainable production of Li2CO3 from brine, which would be beneficial to every user of LIBs.
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