Journal of Chemical Technology and Biotechnology, Vol.86, No.10, 1237-1246, 2011
Separation and purification of scandium by solvent extraction and related technologies: a review
The technologies of solvent extraction, ion exchange, and liquid membrane for the separation and purification of scandium are reviewed. Acidic and neutral organo-phosphorus extractants are most widely used in practice, with high extraction efficiencies. Their disadvantages originate from the high stripping acidity required for the former and the poor selectivity for the latter. Carboxylic acids, amines, and acidic beta-diketone have also been widely used to extract scandium from solutions with low acidities. Mixed extractants or synergistic systems for the solvent extraction of scandium have been developed. Extraction efficiencies are influenced by extraction conditions such as aqueous matrixes and acidities, types of diluents and A/O ratios. Scandium(III) extractions are interfered with by commonly associated elements such as iron(III), zirconium(IV), titanium(IV), thorium(IV), yttrium(III) and lanthanides(III). The advantages and disadvantages of applications of ion exchange and liquid membrane technologies for scandium recovery are reviewed and compared with solvent extraction. (C) 2011 Society of Chemical Industry