Mechanism of Ferric Chloride Facilitating Efficient Lithium Extraction from Magnesium-Rich Brine with Tri-<i>n</i>-butyl Phosphate

The synergistic solvent extraction system comprising tri-n-butyl phosphate (TBP) and FeCl3 has been intensively studied for selective of Li(I) from Mg(II)-rich brine. occurs via the formation an ion-pair complex [Li(TBP)x][FeCl4] in which negatively charged [FeCl4]? neutralizes positively [Li(TBP)x]+. Counterintuitively, many other metal chlorides give much lower efficiency than FeCl3, although they can also form chlorometallate anions similar to [FeCl4]?. In this study, capabilities CuCl2, AlCl3, InCl3, SnCl4 with TBP were examined compared that accompanied by speciation studies. It was found (1) AlCl3 does not [AlCl4]? while (CuCl2, SnCl4) could facilitate (2) neutral solvation complexes strongly, hinders anions, but TBP. Concurrently being able avoid forming facilitates efficient