Selection of a hydrometallurgical process for rare earths extraction from a Brazilian monazite

This work describes the processing of a monazite concentrate containing iron mineral phases in order to recover the rare earth elements (lanthanum was taken as representative for REEs) with minimum iron interference. Three classical routes were tested: acid leaching, alkaline conversion and acid bak...

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Veröffentlicht in:Hydrometallurgy 2021-03, Vol.200, p.105556, Article 105556
Hauptverfasser: Alves, Raphael Cruz, Nascimento, Marisa, Paulino, Jéssica Frontino, Afonso, Júlio Carlos
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Sprache:eng
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Zusammenfassung:This work describes the processing of a monazite concentrate containing iron mineral phases in order to recover the rare earth elements (lanthanum was taken as representative for REEs) with minimum iron interference. Three classical routes were tested: acid leaching, alkaline conversion and acid baking. Control of iron bearing mineral phases was performed during REEs leaching. The most important variables of each process were determinated using experimental design planning. The acid leaching presented high lanthanum extraction but this route was not selective as high Fe extraction was found. Leaching temperature was the most important variable. Alkaline conversion presented medium-to-high lanthanum extraction and a relatively selectivity for iron. Temperature was also the most important variable. Temperature was also the most important variable for the acid baking route, but the amount of acid added to the system and the leaching time were also relevant for iron extraction. High yields were achieved for lanthanum, together with moderate yields for iron. The choice of the best route was determined using the Desirability Function as multiresponse methodology. The alkaline conversion route presented the best combined recovery and selectivity results for lanthanum (with a maximum of 77 wt%) and iron extraction (below 5 wt%). •Testing of three classical routes to recover REE from monazite concentrate.•Influence of experimental parameters on iron interference.•Temperature as the most importante variable in all routes.•Feasibility of the desirability function method to identify the best route.•Alkaline conversion route combined high REE recovery and low iron extraction.
ISSN:0304-386X
1879-1158
DOI:10.1016/j.hydromet.2021.105556