EXTRACTIVE SEPARATION OF ALUMINUM(III), GALLIUM(III) AND INDIUM(III) USING BIS(1,1,3,3-TETRAMETHYLBUTYL)PHOSPHINIC ACID AND ITS SULFUR ANALOGS

The extraction behavior of AI(III), Ga(III) and In(III) was investigat ed using bis(1,1,3,3-tetramethylbutyl)phosphinic acid (MBP) and its su lfur analogues, bis(1,1,3,3-tetramethylbutyl)monothiophinic acid (M-TP ) and bis(1,1,3,3-tetramethylbutyl)dithiophosphinic acid (DTP) as extr actants. A typical chelate extraction behavior was observed in these e xtraction systems in the pH range examined. The degree of extraction w as in the order of In(III) > Ga(III) > Al(III). Moreover, the ability of extractants for mutual separation of these metals from one another decreased in the following order: DTP > MTP > MBP. The quantitative mu tual separation of these metals can be achieved using DTP/hexane with single extraction. In the higher HCl concentration range, however, sli ght extraction of Ga(III) and In(III) was observed; this is due to the extraction of GaCl4- and InCl4- pairing with the protonated extractan ts.