各種の酸性抽出剤によるインジウム（ＩＩＩ）とガリウム（ＩＩＩ）の溶媒抽出

Abstract

Solvent extraction of indium (III) and gallium (III) from nitric acid or aqueous mixture of nitric acid and sodium nitrate solution was investigated using four kinds of acidic extractants, i. e. di (2-ethylhexyl) phosphoric acid (D2EHPA), 2 ethylhexyl 2-ethylhexylphosphonic acid (EHEHPA), di (2, 4, 4'-trimethylpentyl) phosphinic acid (DTMPPA) and 2 bromododecanoic acid (2-BDA), and using toluene as a diluent to identify the extracted species and to evaluate their extraction equilibrium constants. Indium (III) was extracted as the monomeric complex of the type, InR3.3HR, with all extractants. On the other hand, gallium (III) was extracted as the monomeric complex of the type, GaR3, with D2EHPA and EHEHPA while as the complex of the type, GaR3, with DTMPPA and 2-BDA.For both metals, the extraction equilibrium constant increases in the sequence, 2-BDA<DTMPPA<EHEHPA <D2EHPA, which is in accordance with the sequence of acidity of these extractants. The equilibrium constants of indium (III) are greater than those of gallium (III) with all extractants and their ratio increases also in the same sequence as mentioned earlier; the ratio with D2EHPA is above as great as 105.