The reversed-phase extraction chromatography of the rare earths, thorium, uranium and zirconium with a high-molecular-weight amine in sulphuric acid and ammonium sulphate media

Abstract

The column chromatographic behaviour on silica gel impregnated with a high-molecular-weight amine, Amberlite LA-2 (SO 4 2−), of the trivalent rare earths and thorium(IV) in sulphuric acid and acid ammonium sulphate media was investigated. The distribution coefficients of these metal ions decrease with increasing concentration of the acid and sulphate, particularly in the acid system. The separation factor of thorium(IV) to the trivalent rare earths is large enough to separate two metals on the Amberlite LA-2 column in 0.025 M sulphuric acid-1.0 M ammonium sulphate solution. Thorium(IV), zirconium(IV) and uranium(VI) are adsorbed on the column in the same solution. Thorium(IV) is removed easily from the column by elution with 0.1 M sulphuric acid, while uranium(VI) and zirconium(IV) are strongly adsorbed. A separation procedure on the Amberlite LA-2-silica gel column was developed for the trivalent rare earths, thorium(IV), zirconium(IV) and uranium (VI), in which all four of the metal ions can be chromatographically separated by consecutive elution with sulphuric, hydrochloric and perchloric acids.