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Extraction and separation of titanium(IV) with D2EHPA and PC-88A from aqueous perchloric acid solutions

Singh Rajeev K. (Inorganic Chemistry Laboratory, Applied Chemistry Division - Department of Chemical Technology, Matunga, Mumbai, India)
Dhadke Purshottamm M. (Inorganic Chemistry Laboratory, Applied Chemistry Division - Department of Chemical Technology, Matunga, Mumbai, India)

The liquid-liquid extraction of Ti(IV) from perchlorate media using di(2-ethylhexyl) phosphoric acid (D2EHPA) and 2-ethylhexyl prosphonic acid mono-2-ethylhexyl ester (PC-88A) in toluene as the extractant was studied Quantitative extraction of Ti(IV) was observed in the lower acidity range of 0.01 to 0.1 mol dm-3 with 0.003 mol dm-3 D2EHPA and 0.01 mol dm-3 PC-88A in toluene, respectively, and in the higher acidity range of 9.0 to 10.0 mol dm-3 with 0.1 mol dm-3 D2EHPA and PC-88A in toluene. Ti(IV) was completely stripped from the metal loaded organic phase of both the extractants with 3%H2O2 in 1M H2SO4 and determined spectrophotometrically. The stoichiometry of the extracted species was determined on the basis of slope analysis. The extraction in the lower acidity range was found to proceed by a cation-exchange mechanism with the extracted species being TiOR2.2HR while in the higher acidity range it was by solvation with the extracted species being Ti(OH)3ClO4.4HR. Separation of Ti(IV) was also carried out from some associated metals like Fe(III), Al(III), V(V), Ce(IV), Mg(II) and Mn(II). The developed methods were extended for the determination of Ti(IV) in real samples like ilmenite, magnetite and red mud in order to show the practical utility of the extractants.

Keywords: extraction, titanium, separation, D2EHPA, PC-88A and stripping