Extraction of lithium with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester

The extraction equilibrium of lithium with 2-ethylhexyl phosphonic acid mon o-2-ethylhexyl ester, commercial name PC-88A, was investigated, as well as the extraction kinetics of lithium using a hollow fiber membrane extractor, in order to develop a recovery process for lithium from geothermal water o r wastewater from lithium carbonate precipitation in the recycling process for spent lithium batteries. It was found that lithium is extracted by a heptane solution containing PC- 88A, (HR), according to the following equation, Li+,(aq) + 2(HR)(2,org) --> LiR(HR)(3,org) + H+,(aq) where (HR)(2) is the dimer of PC-88A. Furthermore, the extraction mechanism of lithium through the hollow fiber m embrane was elucidated.