From the waste: High selective recovery of scandium REEs from the bauxite residue

• This work employed hydrometallurgical techniques, specifically leaching and SX, to recover Sc from RM. • The impact of several parameters on the extraction system have been investigated. • The separation of Sc from the others metal ions was carried out applying several protocols • The optimal Sc recovery efficiency was attained by using triple SX with 10 vol.% TBP. After 5 minutes of extraction, 81% of the Sc, was recovered. Bauxite residue (red mud) is a waste material from alumina refineries in the Bayer process, containing significant quantities of valuable metals, notably scandium (Sc). The objective of this study is to recover Sc (III) from Hungarian bauxite residue by using hydrometallurgical processes, including solvent extraction and leaching. Red mud directly leached with hydrochloric acid to generate the leachate solution. The significant iron content (∼38%) in red mud makes it hard to recover scandium selectively due to comparable physicochemical characteristics. According to the findings, Fe (III) could be effectively extracted from hydrochloric acid leachate as HFeC1 4 using diethyl ether before Sc extraction. Protocol B demonstrated superior recovery efficiency compared to the other recommended protocols. The most effective Sc recovery efficiency was attained with Protocol B, which utilized triple solvent extraction by TBP: 81% of Sc (869 ppm) with trace amounts of related elements like Ti, Fe, La, Y, and Al. Protocol B takes in the subsequent conditions: a triple solvent extraction utilizing 10 vol.% TBP, an aqueous to organic phase volume ratio of 200 mL:75 mL, and an extraction duration of 5 minutes.