Recovery of Selected Rare Earths from Bauxite Residue by Dry Digestion with Multi-stage Circulation of Leach liquor

The combination of HCl-based dry digestion of bauxite residue and multi-stage circulation of the leach liquor was studied. The proposed processing technology allows to achieve a high selectivity for rare-earth elements with a limited co-dissolution of silica (< 5 wt%). The scandium concentration increased from 7 mg L-1 in stage 1 to 19 mg L-1 in stage 5, while the concentration of yttrium, lanthanum and neodymium increased from an average value of 7 mg L-1 in stage 1 to an average of 18 mg L-1 in stage 5, more than twice the concentration observed for single-stage leaching after dry digestion, and four times higher than the concentration achieved by a conventional direct acid leaching method. The water consumption was reduced by 60% in comparison to the conventional direct acid leaching method.

ISBN:9789082825923

Publication year:2018

Accessibility:Open