| Texto completo | |
| Autor(es): |
Pereira, Barbara Da Rocha
;
Gijon, Diego Teuber
;
Garjulli, Franco
;
Espinosa, Denise Crocce Romano
;
Tenorio, Jorge Alberto Soares
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | MINERALS ENGINEERING; v. 237, p. 21-pg., 2026-03-01. |
| Resumo | |
This study presents an integrated hydrometallurgical route for recovering and purifying rare earth elements (REEs) from a real columbite leachate highly contaminated with Fe, Nb, Th, and U. The process comprises aqueous complexation, solvent extraction (SX), multi-contact stripping, and oxalate precipitation-calcination to obtain high-purity mixed oxides. Different complexing agents (EDTA, oxalic, lactic, and citric acids) were evaluated in combination with D2EHPA as extractant. Sodium citrate (2.5x stoichiometric ratio) was identified as the most effective, reducing Fe co-extraction from 80 % to 29.5 %. The use of 5 % v/v TBP as modifier prevented third-phase formation and improved phase disengagement. Optimized conditions (10) % v/v D2EHPA, pH 1.5, A/O = 1:1) achieved >90 % extraction for HREEs (Dy 90.9 %, Er 94.5 %, Yb 99.0 %) and <35 % Fe and Nb extraction. Three contacts with 5 mol L-1 HNO3 ensured 80-95 % stripping efficiency. Oxalate precipitation assisted by H2O2 oxidation produced two solids. Product B1 (from the organic phase) reached 99.22 wt% total REO, with 78.8 % HREE enrichment (Y2O3 + Dy2O3 50 wt%) and Fe2O3 0.78 wt%. Product B2 (from the raffinate) was LREE-dominated (95.1 wt% purity), containing Th2O3 = 4.6 wt%. Subsequent lime precipitation at pH 5 selectively removed Fe (97 %) and Nb (91 %), yielding a clean effluent. The proposed process demonstrates high selectivity, purity, and environmental compatibility for sustainable REE recovery from sulfate-rich residues. (AU) | |
| Processo FAPESP: | 21/14842-0 - Elucidação do mecanismo de complexação de organometálicos entre extratantes orgânicos e elementos terras raras |
| Beneficiário: | Amilton Barbosa Botelho Junior |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 23/01032-5 - Separação de metais críticos através de membranas suportadas com líquidos: avaliação da interação sinérgica entre organofosforados e membranas |
| Beneficiário: | Amilton Barbosa Botelho Junior |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado |
| Processo FAPESP: | 19/11866-5 - Desenvolvimento de processos inovadores para recuperação de metais críticos |
| Beneficiário: | Denise Crocce Romano Espinosa |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 22/01159-2 - Avaliação de uma rota de recuperação de metais terras raras a partir de resíduo eletroeletrônico |
| Beneficiário: | Fernanda Fajardo Nacif Petraglia |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado Direto |