Lithium 7 Isotope (Li) desorption from a degraded amberlite IRN 217 lithiated mixed-bed ion-exchange resin

Abstract

This study investigated the possibility of desorpting the lithium isotope (7Li+) from the cation part of an Amberlite IRN 217 lithiated mixed-bed resin that had been deemed unsuitable for use as a result of anion degradation and the release of organically bound impurities. The desorption of the isotope from the cation part of the mixed-bed resin was studied using dilute hydrochloric (HCl) and sulphuric acid (H2SO4) solutions. The initial experiments were carried out in a batch reactor in order to determine the best eluent acid concentration to be used in a continuous ion-exchange packed-bed column. The favorable eluant concentration was found to be 1 M HCl and 1 M H2SO4, respectively. In the continuous desorption ion-exchange column, a desorption rate >90% was achieved within 18 bed volumes (BV) of HCl and H2SO4 eluants. The concentration of the released anion and cation leachates in the effluent that had been recovered was also determined. The mathematical model developed and the kinetic parameters used in the model represented the desorption kinetics of the 7Li+ isotope from the cation part of the lithiated resin. The correlation coefficient (R2) between the experimental and the simulated data proved to be 0.99 and 0.94 for 1 M HCl and 1 M H2SO4, respectively. This revealed a sufficient correlation for comparison between the experimental and simulated data.