Application of McCabe—Thiele for Predicting the Performance of Continuous Ion Exchange Systems in Battery Metal Purification

Abstract

Ion exchange is commonly used for the removal of impurities from solution streams containing battery metals prior to generating the final product. For full scale processing options, the ion exchange technology utilized is a critical consideration for the success of the project. While different design approaches have been adopted for ion exchange systems, few have made use of graphical techniques. This study shows that McCabe—Thiele graphical techniques can be interpreted for the design of continuous ion exchange plants and used as a tool for predicting their performance. An investigation was undertaken to remove a contaminant metal species, MD, from a solution containing a valuable metal of interest, MA. The performances of continuous fixed bed, moving bed and continuous counter-current ion exchange (CCIX) pilot operations under different conditions were compared to the predicted performance based on batch tests conducted at bench scale. Applying McCabe—Thiele graphical techniques to the batch adsorption equilibrium isotherm and interpreting the outcome in conjunction with the results from the bench scale column breakthrough test allow one to accurately predict: 1. The resin loadings and corresponding barren concentrations that are achieved in each extraction stage of the adsorption circuit. 2. The breakthrough profile from each stage of continuous operation This study provides a comprehensive approach to predicting the performance of different continuous ion exchange contacting systems, which enables ease of design and process selection.