Enhancing the Recovery of Rare Earth Elements from Red Mud

An overview of methods used to enhance the recovery of rare earth elements (REEs) from bauxite residue or red mud (RM) is given. RM is a byproduct of the Bayer alumina production process. The composition of RM depends on the bauxite source and digestion protocol. This study aimed at developing and improving technological steps to recover REEs such as Sc, La, and Y from RM. Parameters such as leaching agent, contact time, temperature, and solid-to-liquid ratio were investigated to achieve optimum REE recovery from RM by combining hydrometallurgical steps such as acid digestion, ion exchange, and solvent extraction. The process was selected by considering its efficiency for selective recovery of Sc, La, and Y and suitability for subsequent solvent extraction and ion exchange of the leaching solution to separate the individual REEs.