Removal of Impurities from Saturated Ion-Exchange Resins by Frontal-Gradient Purification in Schemes for Recovery of Nonferrous, Rare, and Rare Earth Metals

Abstract

In this study, we investigate the conditions for metal separation or removal of impurities from ion exchangers using the method based on frontal-gradient treatment of the phase of ion exchangers saturated with solutions of metal compounds, which exhibit enhanced selectivity with respect to functional groups of these ion exchangers. The efficiency of frontal-gradient removal is demonstrated for the rhenium–selenium, rhenium–molybdenum, cerium(IV)–lanthanum, and cerium(IV)–scandium systems. Proper selection of an ion exchanger used for saturation with a target component and the nature of its functional groups are the key factors for these separation processes. Industrial separation technologies to be implemented at a number of enterprises have been developed on the basis of studies conducted using these systems.