Solvent extraction separation of gallium, indium and thallium with high relative molecular mass amine from citrate solutions

Abstract

A novel method is proposed for the solvent extraction separation of aluminium, gallium, indium, thallium(I) and thallium(III). Gallium was quantitatively extracted from 0.01 M citric acid between pH 2.0 and 3.5 with 0.1 M Amberlite LA-2 in xylene, stripped with 0.5 M hydrochloric acid and determined spectrophotometrically at 505 nm as its complex with 4-(2-pyridylazo)resorcinol (PAR). Indium was quantitatively extracted from 0.01 M citric acid between pH 2.5 and 3.6 with 0.1 M Aliquat 336S in xylene, stripped with 0.5 M hydrochloric acid and determined spectrophotometrically at 510 nm with PAR. Thallium was quantitatively extracted with 0.1 M Aliquat 336S in xylene from 0.01 M citric acid between pH 2.0 and 6.0, stripped with 0.5 M perchloric acid and determined spectrophotometrically at 610 nm as its complex with crystal violet. The separation of aluminium, gallium, indium, thallium(I) and thallium(III) was effected after extraction by stripping aluminium or thallium(I) with water followed by stripping of gallium with 2.5 M hydrobromic acid, indium with 0.5 M hydrochloric acid and finally thallium(III) with 0.5 M perchloric acid. These elements were also separated from several multi-component mixtures. The method was extended to the analysis of real samples.