Title: Application of various extractants for liquid-liquid extraction of lithium
Abstract: The extraction of lithium is presently too inefficient to be economically or commercially viable. In this piece of work, the effectiveness of several extraction methods was analyzed. The various extractants engaged for extraction of Li were TOPO, TOA, Cyanex 272, D2EHPA, Aliquat 336, [Aliquat 336][Cyanex 272], [Aliquat 336][D2EHPA] and [Cyphos IL 101][D2EHPA]. Experiments are performed with the variation of operating parameters such as pH of the aqueous solution and concentration of extractants, etc. With all extractants and kerosene as the diluent, maximum lithium extraction was obtained between pH 6 to 7. About 27 % and 30 % of lithium were extracted using 0.1 mol/L Cyanex 272 and 0.1 mol/L TOPO respectively. Similarly, using 0.1 mol/L Aliquat 336 and 0.1 mol/L TOA as an extractant, below 20 % lithium was extracted. About 53 % of lithium was extracted by using the functionalized ionic liquid [Cyphos IL101][D2EHPA]. However, by adding lactic acid to the aqueous phase, 0.1 mol/L D2EHPA showed enhanced lithium extraction. When the O/A ratio was maintained at 2:1, about 70 % of lithium was extracted at pH 6. Also, the extraction of lithium was studied in the presence of several alkali and alkaline-earth metals such as Na+, K+, Mg2+, and Ca2+.