Abstract
The extraction of rare earth elements is becoming increasingly essential due to their many applications in current and emerging advanced material technologies. However, in many rare earth deposits, rare earth minerals are associated with radionuclides; specifically, thorium and uranium. The radioactive nature of these elements is a major concern during processing. Techniques such as solvent extraction and precipitation have been employed in this regard to minimize the radioactivity levels and address any related processing or environmental concerns. However, they face various challenges such as high chemical reagent consumption, secondary waste generation, and limited selectivity, which hinder either their scalability or sustainability. The current study provides a literature review about these technologies to provide critical insights on their applications and discuss the challenges hampering their extensive use in the mining industry. Biotechnology is also evaluated and highlighted as a promising, cost-effective, and low-environmental-impact option for the selective recovery of radionuclides from rare earth elements. Specifically, pyoverdine siderophores were discussed due to their catecholates and hydroxamate moieties which have high affinity for radionuclides to enhance selective recovery during rare earth processing. Conversely, integration of this approach into existing mineral processing flowsheets is a constraint. Hence, future studies should focus on optimizing the kinetics of siderophore synthesis and explore a hybrid approach to combine the biotechnological and conventional techniques.