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Extraction and separation studies of Ga(III), In(III) and Tl(III) using the neutral organophosphorous extractant, Cyanex-923

Pawar S.D. (Inorganic Chemical Laboratory, Institute of Chemical Technology Uninversity of Mumbai, Matunga, Mumbai-400 019 India)
Dhadke P.M. (Inorganic Chemical Laboratory, Institute of Chemical Technology Uninversity of Mumbai, Matunga, Mumbai-400 019 India)

The neutral extractant, Cyanes-923 has been used for the extraction and separation of gallium(III), indium(III) and thallium(III) from acidic solution. These metal ions were found to be quantitatively extracted with Cyanex-923 in toluene in the pH range 4.5–5.5, 5.0–6.5 and 1.5–3.0 respectively, and from the organic phase they can be stripped with 2.0 mol dm-3 HNO3, 3.0 mol dm-3 HNO3 and 3.0 mol dm-3 HCl, respectively. The effect of pH equilibration period, diluents, diverse ions and stripping agents on the extraction of Ga(III), In(III) and Tl(III) has been studied. The stroichiometry of the extracted species of these metal ions was determined on the basis of the slope analysis method. The reaction proceed by solvation and the probable extracted species found were [MCl3. 3Cyanex-923][where M = Ga(III) or In(III)]and [HTlCl4. 3Cyanex-923]. Based on these results a sequential procedure for the separation of Ga(III), In(III) and Tl(III) from each other was developed.

Keywords: solvent extraction, Cyanex-923, Ga(III), In(III), Tl(III), stripping, separation.