An environmentally friendly lithium extraction system utilizing Cyanex 272 as iron-fixed reagent

Solvent extraction has emerged as an extremely effective and highly promising approach for extracting lithium ions from salt lake brine, primarily due to its remarkable Li + selectivity, cost-effectiveness, and high efficiency. In this paper, the utilization of bis-(2,4,4-trimethylpentyl)-phosphinic acid (Cyanex 272) as an iron-fixed reagent in an organic solution, along with tributyl phosphate (TBP) as the extractant and FeCl 3 as the co-extractant, is proposed. Compared to the traditional TBP-FeCl 3 system, TBP-Cyanex 272 extraction system holds potential advantages in terms of a more environmentally friendly extraction process. Particularly, during the stripping process, the coordination of Fe 3+ with Cyanex 272 and TBP at a lower Cl − concentration allows Fe 3+ to be retained in the organic phase, thereby facilitating a greener extraction process. This method has effectively overcome the technical challenges associated with TBP-FeCl 3 systems, such as strong acid stripping and strong base saponification. Additionally, as an environmentally friendly extraction system, TBP-Cyanex 272 demonstrates exceptional performance in terms of lithium extraction efficiency and phase separation.