Improved Technology of Scandium Recovery from Solutions of Bauxite Residue Carbonation Leaching

Scandium is considered to be the best alloying metal for aluminium. Aluminum-scandium alloys are characterized by unique properties: high thermal and corrosion resistance, durability, superplasticity, self-hardening capacity, fine weldability, and have potential for application in such industries as aerospace, automotive and shipbuilding. RUSAL has developed a series of technologies to promote wide application of scandium alloys, including the environmentally and Bayer process-friendly technology of scandium oxide extraction from bauxite residue. This paper shows the results of research on scandium sorption from bauxite residue carbonation leaching solutions at laboratory and at pilot plant scales at one of Rusal's alumina refineries. Optimum conditions for sorption and desorption processes were defined not only assuring improved scandium concentrate quality but also allowing to obtain the lowest cost of scandium oxide as compared to other industrial scandium oxide production technologies.