| Texto completo | |
| Autor(es): |
Garjulli, Franco
;
de Carvalho, Thamyres Cardoso
;
Tenorio, Jorge Alberto Soares
;
Coleti, Jorge Luis
;
Espinosa, Denise Crocce Romano
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF SUSTAINABLE METALLURGY; v. N/A, p. 15-pg., 2025-01-24. |
| Resumo | |
Cobalt catalysts are fundamental in the chemical industry in accelerating reactions due to their resistance to oxidation and thermal stability. However, over time, they lose effectiveness and are discarded, generating environmental waste. Traditionally, the recovery of these catalysts involves methods that emit CO2, worsening environmental problems. This study used hydrogen (H-2) as a reductant in the pyrometallurgical recovery of metallic cobalt from spent catalysts, avoiding CO2 emissions. Different temperatures and flow rates were tested, and it was observed that sintering influences the reduction rate. The reduction process occurred in two distinct steps: first, cobalt(III) was reduced to cobalt(II), followed by reduction to metallic cobalt. The SEM-EDS, XRF, and XRD techniques confirmed the effectiveness of the process, and kinetic studies indicated that diffusion in the solid-gas layer is the main mechanism controlling the reactions. The reduction route with H-2 proved to be an efficient, simple, and applicable method for recycling exhausted mixed cobalt oxide (Co3O4) catalysts compared to methods proposed in the literature, as the use of H-2 avoids the emission of CO2 during the recovery process. This aspect is relevant to growing global concerns about reducing the carbon footprint and increasing environmental sustainability. [GRAPHICS] . (AU) | |
| 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: | 20/00493-0 - Mineração sustentável: recuperação de matérias-primas críticas de baterias usando tecnologias ambientalmente amigáveis |
| Beneficiário: | Jorge Alberto Soares Tenório |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |