Recovery of lithium from salt-lake brines using solvent extraction with TBP as extractant and FeCl3 as co-extraction agent

A novel extraction process to recover lithium ions from simulated salt lake brines with high Mg/Li ratio was developed. Tributyl phosphate (TBP), FeCl3 and diethyl succinate were used as extractant, co-extraction agent and diluent, respectively. Effects of extraction conditions containing the volume concentration of TBP, Fe/Li molar ratio and O/A phase ratio on extraction performances were studied. The highest one-stage extraction efficiency of lithium ions and separation factor were about 65% and 350, respectively. In addition, the third phase did not appear over all the volume concentrations of TBP. HCl + MgCl2 and HCl + NaCl were used as washing and stripping agents, respectively. Effects of washing and stripping conditions on washing and stripping performances were investigated too. Mg(OH)2 and MgCO3 were used as regeneration agents to regenerate the organic phase. The extraction efficiency of lithium ions remained at about 53% during reusing the organic phase ten times, demonstrating that the proposed extraction system had good stability and reusability.