Solvent extraction of samarium from aqueous nitrate solution by Cyanex301 and D2EHPA

Solvent extraction studies of Sm (III) from aqueous nitrate solution have been focused on using Cyanex301 (bis-2,4,4 trimethylpentyl dithiophosphinic acid) alone and in combination with D2EHPA (di-2-ethylhexyl phosphoric acid). The effect of operating parameters, such as time, nitrate ion, aqueous phase acidity, concentration of the extractant, temperature on the samarium extraction and various acid solutions on the metal stripping from the loaded organic phase were investigated. The synergistic effect showed that addition of D2EHPA to Cyanex301 extraction system led to an increase in extraction efficiency of Cyanex301 in low concentration range (0.01-0.05 M). Furthermore, mixtures of the extractant provided better stripping performance at low acid concentration in comparison with D2EHPA system. The values of the thermodynamic parameters, equilibrium constants and stoichiometric coefficients for both extractants and their mixtures were calculated. (C) 2013 Elsevier B.V. All rights reserved.