Recovery of lithium from salt-lake brine by liquid–liquid extraction using TBP-FeCl3 based mixture solvent

In this study, a complete cyclic process was developed for the lithium extraction from high-concentration salt-lake brine by using a high flash point, low water solubility, and low toxicity diluent mixed with the TBP-FeCl 3 -based organic solvent. The process was composed of four sections, including extraction, scrubbing, stripping, and regeneration. The optimal conditions for each section were determined first. Then, a 13-stage cyclic extraction process was designed and validated experimentally for the high lithium concentration brine, which reached 8.612 g/L. By using the diluent at the optimized conditions, the overall recovery of lithium was higher than 96%. The stripping liquid contained 38.87 g/L Li + , while all the ratios of impurities of sodium, potassium, and magnesium to lithium were less than 0.1. The aims of enrichment and purification of Li + from the complicated brine system were achieved by the developed extraction process with little Fe loss, which provided the technical support for the development of the salt-lake lithium resource.