Temperature-responsive liquid-liquid extraction of Li+ from high Mg/Li ratio brine

Abstract

Exploring a facile method to recover Li+ is crucial for liquid-liquid extraction from high Mg/Li ratio brine for energy conversion and storage. A simple and effective approach herein that involves the lithium recovery from high Mg/Li ratio brine at a controlled temperature is proposed. Liquid-liquid extraction of Li+ from high Mg/Li ratio brine was carried out using tributyl phosphate (TBP) diluted in temperature-responsive ionic liquid as the extraction organic phase. The introduction of this ionic liquid allows for the solid-liquid conversion of the extraction phase by adjusting the temperature, and then achieves effective phase separation after liquid-liquid extraction. The parameters such as pH value, the dosage of IL, and phase ratio were optimized by experiments to achieve more than 80% of lithium recovery from a high Mg/Li ratio solution. The loaded organic phase was regenerated by HCl stripping, and the stripped organic phase can be recovered with no crud or emulsification during the process. In this work, a novel and green method was developed for lithium selectivity recovery by using a switchable temperature-responsive TBP-IL system.