Investigations into Optimized Industrial Pilot Scale BR Leaching for Sc Extraction

ScandiumScandium is a critical metalCritical metal with increasing demand in modern technologies, like solid oxide fuel cells and light-weight Al-Sc alloys. Sc is present at considerably high concentrations in various metallurgical by-products, including the bauxite residueBauxite residue (BR). ScandiumScandium extraction from the Greek bauxite residueBauxite residue (BR) that contains 70–100 mg/kg Sc has been demonstrated at an industrial pilot plant at MYTILINEOS. BR has been treated with sulfuric acid at conditions that allow for low acid consumption. In such conditions, high Sc leaching selectivity is achieved over Fe and Ti, which are the main impurities for the further purification of the leachate through the ion-exchange technique. This paper reports on the recent investigations on the effect of pH control during the leaching process, which can lead to optimized results. Moreover, the treatment of the produced leachate solution is also studied, in order to further refine it, prior to the ion-exchange.