Mass balance study of a multistage process for the purification of a fluorspar by-product from a rare earth element carbonatite deposit.

Nguyen, Thi Yen Chau; Tran, Lan Huong; Coudert, Lucie; Mueller, Kristin K.; Mercier, Guy et Blais, Jean-François ORCID: https://orcid.org/0000-0003-3087-4318 (2021). Mass balance study of a multistage process for the purification of a fluorspar by-product from a rare earth element carbonatite deposit. Minerals Engineering , vol. 171 . p. 107122. DOI: 10.1016/j.mineng.2021.107122.

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Résumé

Fluorspar, also known as fluorite (CaF₂), is commercially important in metallurgical (e.g. used as slag viscosity modifier), ceramic (e.g. used to manufacture glass), and chemical industries (e.g. production of commercial HF). In the present study, a process has been developed to produce a ceramic grade fluorspar by-product from a rare earth element (REE)-bearing carbonatite deposit. The objective of the present study was to conduce a mass balance assessment of a CaF₂ by-product purification process as well as an economic evaluation of the final flotation step to determine the advantage/limitation of this additional step to improve the purity of CaF₂ from metallurgical to ceramic grade. After an initial flotation step to produce feed, the fluorspar purification process consisted of four steps. Firstly, a magnetic separation step was conducted to pre-concentrate the fluorspar into a non-magnetic fraction, while concentrating Fe- and REE-bearing minerals in the magnetic fraction. Secondly, the non-magnetic fraction was subjected to an acid leaching step to solubilize carbonates. Thirdly, the leached solid was treated again by magnetic separation to remove the further liberated REE-bearing minerals from the fluorspar minerals. Finally, a flotation step was performed to depress silicate minerals in the tailings fraction and thus to improve fluorspar grade in the concentrate. The purity of fluorspar increased from 15.6% in the feed (no commercial value, residue to be disposed of) to 95.1% in the final product (ceramic grade). According to the mass balance calculations, approximately 98.6 g of ceramic grade CaF₂ was recovered from 1 kg of feed material and the output/input ratio of fluorspar was estimated at 94.0%. The costs of the flotation process develop to improve the purity of CaF₂ from metallurgical to ceramic grade were estimated at 194 $CAD.t⁻¹, while the revenue to be generated by the ceramic grade fluorspar obtained were estimated at 244 $CAD.t⁻¹, indicating that the additional flotation step is economically feasible and beneficial to the company, not only to upgrade fluorspar by-product (from commercial to ceramic grade), but also to generate a profit of at least 50 $CAD.t⁻¹.

Type de document:	Article
Mots-clés libres:	fluorite; fluorspar; carbonatite; REEs; magnetic separation; acid leaching
Centre:	Centre Eau Terre Environnement
Date de dépôt:	15 sept. 2021 17:36
Dernière modification:	16 août 2023 04:00
URI:	https://espace.inrs.ca/id/eprint/11941

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