2nd International Bauxite Residue Valorisation and Best Practices Conference, Date: 2018/05/07 - 2018/05/10, Location: Athens (Greece)
Proceedings of the 2nd International Bauxite Residue Valorisation and Best Practices Conference, Athens (Greece), 7-10 May 2018
Author:
Keywords:
rare earths, bauxite residue, red mud
Abstract:
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.