Toward greener comprehensive utilization of bastnaesite: Simultaneous recovery of cerium, fluorine, and thorium from bastnaesite leach liquor using HEH(EHP)

This paper describes a novel process for conducting the extraction and recovery of cerium, fluorine, and thorium from a bastnaesite sulfuric leaching solution using HEH(EHP) (2-ethylhexylphosphonic mono-2-ethylhexyl ester) as the solvent, and investigates the effects of HEH(EHP) concentration, the stoichiometric quantity of H2O2, and H2SO4 concentration in the Th(IV) stripping liquor on extraction quantity and purity. Analysis of the process shows that Ce(III) extraction capacity with HEH(EHP) is negligible, and extraction efficiency for the elements is in order of Ce(IV) > F(I) > Th(IV) >> Ce(III). After coordination scrubbing of F(I) with AI(III), Ce(IV) is reductively stripped with H2O2 and HCI, allowing recovery of CeO2 with a purity of 99.95%. Furthermore, this paper provides appropriate technical parameters for industrial application of the extraction system-confirmed by a multistage countercurrent extraction test-showing that this process provides a more environmentally sound integrated separation and recovery flow of rare earths from bastnaesite. (C) 2012 Elsevier B.V. All rights reserved.