Rare Earth Element Recovery Using Monoethanolamine

Current methods of rare earth element (REE) recovery from industrial solutions are environmentally untenable and have significant waste management challenges. Increasing global REE consumption necessitates the development of new, sustainable means of production. Herein, we report a means of recovering aqueous REEs using monoethanolamine and carbon dioxide as predicted using the Mixed-Solvent Electrolyte thermodynamic model. Validation experiments have demonstrated the > 99% recovery of Nd³⁺ as its normal carbonate, with the filtrate containing monoethanolamine hydrogen chloride. Additional experimentation also demonstrated the > 99% recovery of aqueous La³⁺ and Y³⁺ as their respective normal carbonates. These findings demonstrate that a thermodynamic simulation engine may be used to decrease the number of empirically driven experiments required to develop a new, high yield REE recovery unit operation that is applicable to concentrated and dilute aqueous solutions typical of industrial streams.