A highly efficient solvent system containing ionic liquid in tributyl phosphate for lithium ion extraction

Application of a room temperature ionic liquid (RTILs), 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]), in the extraction of lithium ion from salt lake brine using tributyl phosphate (TBP) as extractant was investigated. The effects of temperature, pH value of solution, phase ratio and other factors on the extraction were studied in detail. The preliminary experimental results had demonstrated that, compared with using conventional extraction system, the extraction efficiency had been increased greatly in this ionic liquid system. Study on the mechanism revealed that the extraction most likely occurred by a cation exchange mode in this system. This work highlights the vast opportunities in separation applications for ionic liquid.