Metallurgical processes for scandium recovery from various resources: A review

Metallurgical processes for scandium recovery from various resources are reviewed. Scandium is mainly recovered as by-product from residues, tailings and waste liquors in the production of other metals such as rare earths, uranium, titanium, tungsten, aluminium, nickel, tantalum and niobium. Bauxite and nickel laterite ores are proposed as the most promising scandium resources for its production. Currently, the methods combined with hydro- and pyro-metallurgical processes, including ore pre-treatment, leaching, solvent extraction, precipitation and calcination, are commonly used for scandium recovery. New technologies for scandium recovery such as selective leaching and solvent extraction are possible development direction in the future. ► This paper comprehensively reviews the metallurgical processes to recover scandium from various sources. ► Residues, tailings and waste liquors in the production of other metals are the resources for scandium. ► The most promising scandium resources for its production are bauxite and nickel laterite ores. ► Combined hydro- and pyro-metallurgical processes are commonly used for scandium recovery.