Separation and recovery of titanium and scandium from the red mud

Abstract

In this study, a full process in recovery of titanium and rare earth elements (REEs) from the red mud was developed. The suggested route consists of four main stages in the process flow diagram: sample preparation, leaching, hydrolysis, and solvent extraction. Sample preparation is proposed using a two-stage water washing followed by calcination to remove the acid-consuming components of the red mud. Dissolution of the Ti and REEs (with a focus on Sc) was developed using sulfuric acid followed by a hydrolysis process for the titanium precipitation. Concentration of the REEs in the solution was performed using a solvent extraction process. The dissolution efficiency of Ti and Sc were found 91 % and 93 %, respectively. Ti precipitation efficiency was about 86 %, and the final TiO2 product had a purity of 92 %, with the main impurities of a mixed iron and titanium oxide. After recovering Ti, Sc concentration using solvent extraction was studied. Using D2EHPA and alkaline stripping, Sc was concentrated from 69 ppm in the red mud to 1125 ppm in the obtained precipitate. The proposed process has the potential to be considered industrially due to its relative simplicity, high recovery yield, integrity, and utilization of low-cost reagents.