Thorium adsorption behaviour on mixed ammonium lanthanum oxalate, LAOX

The cation-exchange properties of mixed ammonium lanthanum oxalate, LAOX, w ere studied by batch equilibration as a function of the concentration of so me cations, such as alkaline earths or ammonium and of some anions and acid s. The distribution coefficients for thorium are high, while U(VI) is not a dsorbed over a large acidity range, Thus, the separation of thorium from ur anium may be successfully carried out. The experimental conditions of adsor ption, elution and recovery of thorium were investigated as well, by using chromatographic columns filled with LAOX, in order to set best the separati on conditions from uranyl ions. Instrumental neutron activation analysis, I CP emission spectrometry and the UV spectrometry were used to evaluate the thorium, uranium and lanthanum concentrations. (C) 1999 Elsevier Science Lt d. All rights reserved.