Abstract
Rare earth elements (REEs) are critical raw materials underpinning advanced manufacturing, clean energy technologies, electronics, and defense applications. As global demand accelerates and supply-chain risks intensify, governments and industry are seeking separation technologies that are more sustainable, flexible, and resilient than conventional solvent extraction. While solvent extraction remains the industrial standard, it is capital-intensive, chemically complex, and associated with significant environmental and permitting challenges. This study evaluates electrodialysis as a potential alternative or complementary separation technology for REE processing. Using synthetic solutions representative of industrial REE leachates, a multi-stage electrodialysis separation circuit was developed to mirror the functional performance of conventional solvent extraction flowsheets. The system was assessed using different chelating agents commonly employed in REE processing, enabling systematic evaluation of separation efficiency across individual stages. Experimental results demonstrate that electrodialysis can achieve stage-wise separation factors that are competitive with those reported for solvent extraction under comparable conditions, supporting its technical feasibility for REE fractionation. For industry stakeholders, these findings indicate that electrodialysis may offer advantages in process modularity, chemical inventory reduction, and operational simplicity. For government and policy stakeholders, the technology presents opportunities to lower environmental impact and improve regulatory compliance in critical-mineral processing. This work establishes electrodialysis as a promising candidate for next-generation REE separation circuits and provides a quantitative basis for further scale-up, technoeconomic evaluation, and integration into sustainable critical-materials supply chains.