A Comparative Study of the Leaching Processfor Extraction of Scandium from Red Mud Slag

Scandiumisclassifiedas arare earth element. Its existencesaregeochemically in small amounts as associate minerals. Consequently,scandiumproductionis minimally from processing residues of major minerals. Indonesia has large bauxite deposits, and it is processed into alumina, producing bauxite residueas a by-product. The bauxite residuecontains rare earth metals, including scandium. In this study, various ways of extracting scandiumfrom bauxite residueslagwere carried out. The bauxite residue beneficiation processwas donethrough a smelting reduction process followed by magnetic separation. Scandiumextractions werecarried out fromthebauxite residue slag througha leaching process with concentrated sulfuric, sulfation, alkali fusion, and a 2-stage acid leaching. The best percentage of scandium extracted was obtained at 88.40%, using the 2-stageacid leaching at the acid concentration of 500 g/kg, the temperatureof 90oC, and the leaching time at 3 hours for each leaching stage. In addition, the best neodymium extracted achieved 76,97%, using the alkali fusion, fused in NaOH at 700oC for 3 hours.