Liquid–liquid extraction and separation of lanthanum(III) from titanium(IV), zirconium(IV), hafnium(IV), thorium(IV) and uranium(VI)

Abstract

A method for the solvent extraction of lanthanum from salicylate media by using triphenylphosphine oxide is presented. Lanthanum is extracted quantitatively from 2.0 × 10^–2–5.0 × 10^–2 mol dm^–3 sodium salicylate solution at pH 4.0–5.0 using 1.5% triphenylphosphine oxide dissolved in toluene. The extracted metal ion is stripped using water and estimated spectrophotometrically following complexation with Thoron-I. A possible mechanism of extraction is discussed. The method permits the separation of lanthanum from titanium, zirconium, hafnium, thorium and uranium.