Selective Process Steps for the Recovery of Scandium from Jamaican Bauxite Residue (Red Mud)

Abstract

We report the development of a process allowing the selective, sustainable recovery of scandium (Sc) with 75% efficiency from Jamaican bauxite residue (red mud), a waste product from aluminum production. The process design is inspired by green chemistry principles and focuses on establishing highly selective process steps (sulfation, leaching, and precipitation) in order to minimize costs and waste produced. In addition to scandium oxide, the chosen approach produces mixed rare earth oxides as a side product, thus isolating an average of 88% of all rare earth elements contained in red mud. Furthermore, in light of predicted supply shortages of the critical material Sc and the need to establish cost-effective bauxite residue remediation techniques, a systematic Monte Carlo-based economic performance assessment framework is developed in order to evaluate the economic prospects of the proposed process system in the presence of irreducible uncertainty.

Quaternization of algal/PEI beads (a new sorbent): Characterization and application to scandium sorption from aqueous solutions

“…Leaching processes (sometimes associated to roasting, [7]) constitute the first step in the recovery of Sc(III) from solid wastes using acidic solutions [6,[8][9][10]. For valorization of leachates, processes such as selective precipitation [11,12] and solvent extraction [13][14][15][16] are frequently reported for the treatment of concentrated solutions. The loss of expensive and toxic reagents (extractant and solvent being partially dissolved in water) makes solvent extraction environmentally and economically debatable in the case of dilute solutions (i.e., below 100-150 mg Sc L −1 ).…”

Novel Approach for Enhanced Scandium and Titanium Leaching Efficiency from Bauxite Residue with Suppressed Silica Gel Formation

“…Hence, valorization of BR has been in the focus of great interest 8 – 11 . Since the processing route must be tailored in a relation to the geological presence of the BR as a consequence of different mineralogy and association of the phases, several processes have been proposed 12 – 16 . Hydrometallurgical, pyrometallurgical and the combination of these methods have been previously investigated for the recovery of metals from red mud 16 – 20 .…”

Effect of Aqueous Media on the Recovery of Scandium by Selective Precipitation

“…Previously, complete or partial recovery of Sc from bauxite residues was reported to be achieved mainly by solvent extraction, ion exchange, or the combination of these two techniques, as a result of its low concentration in the leachates [14][15][16][17][18][19][20]. Zhang et al recovered 91% of Sc from bauxite residue leachates by inorganic metal(IV)-phosphate ion exchangers, although Fe(III) was found to be an interfering ion in this process [20].…”