Selective separation of thorium from rare earths, zirconium and other elements by cation-exchange chromatography in hydrobromic acid media

Abstract

Thorium can be separated from La, Sc, Zr, Ti(IV), Ba, Ca, Mg, Al, Mn(II), Fe(IlI), Bi(lII), Pb(Il), Pd(II), Zn, Cu(II), Ni(II), U(VI) and V(V) by eluting these elements with 5.5 M hydrobromic acid from a column of AG50W-X4 cationexchange resin. Thorium is retained and can be eluted with 5 M nitric acid with recoveries of better than 99.9% for amounts from about 200μg to more than 400 mg. Au(III) and Ga(III) can be eluted with 0.5 M hydrobromic acid in 90% acetone before the elution with 5.5 M hydrobromic acid. Y, Ce, the other rare earths, Sr, Be, Hf, Cr(III), Co(II), Cd, In, Hg(II), Li, Na, K, Rb, Cs, Sn(IV), Ge(IV), Se(IV), Te(IV), As(III), Sb(III), Pt(IV), Ir(III), Ir(IV), and Rh(III) have not been investigated quantitatively, but should also be separated according to their distribution coefficients and elution curves. Some relevant distribution coefficients, elution curves and results for the analysis of synthetic mixtures are presented.