Reduction by hydrogen of the waste rock minerals constituents of a vanadium ore.

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Autor(es): dc.creatorFerreira, Túlio Simplício-
Autor(es): dc.creatorRodrigues, Isabel Cristina Braga-
Autor(es): dc.creatorLeite, Adilson do Lago-
Autor(es): dc.creatorOliveira, Victor de Andrade Alvarenga-
Data de aceite: dc.date.accessioned2025-08-21T15:14:26Z-
Data de disponibilização: dc.date.available2025-08-21T15:14:26Z-
Data de envio: dc.date.issued2024-11-20-
Data de envio: dc.date.issued2024-11-20-
Data de envio: dc.date.issued2022-
Fonte completa do material: dc.identifierhttps://www.repositorio.ufop.br/handle/123456789/19061-
Fonte completa do material: dc.identifierhttps://doi.org/10.20021/sjr.v3i2.66-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/1007517-
Descrição: dc.descriptionA sample of vanadium ore has been characterized by X-ray diffractometry (XRD), scanning electron microscopy coupled with dispersive energy spectrometry (SEM-EDS) and thermogravimetric analysis (TG). The mineral composition was determined by the Rietveld method and the results showed that the major mineral constituents are maghemite (52.32%) and magnetite (15.73%). The SEM-EDS images showed that the vanadium is diffused over the crystal structure of almost all the minerals. Hydrogen reduction was assessed by thermogravimetry (TG), where three thermal events has been identified in the TG curves. The first event was probably related to two chemical reactions: (i) the oxidation of the mineral ulvospinel by different vanadium oxides, followed by the reduction of the products of this redox reaction by the hydrogen, and (ii) the reduction of the mineral magnesioferrite by the hydrogen. The other two events were attributed to the dehydroxylation of the phyllosilicates (greenalite, cronstedtite and sudoite) and the reduction of maghemite, magnetite, titanium oxides and vanadium oxides. Finally, the integration isoconversional method was used to determine the apparent activation energy (Ea), which ranged from 44.28kJ.mol-1 to 82.47 kJ.mol-1 for the Kissinger-Akahira-Sunose method (KAS), and from 33.44kJ.mol-1 to 65.54kJ.mol-1 for the Ozawa-Flynn-Wall method (OFW). These values imply that the reduction is controlled by mixed process for low conversion values (diffusion and chemical reaction are the controlling steps) and by chemical reaction for high conversion values.-
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Idioma: dc.languageen-
Direitos: dc.rightsaberto-
Direitos: dc.rightsFor all articles published in SJR, copyright is retained by the authors. Articles are licensed under an open access Creative Commons CC BY-NC 4.0 license, meaning that anyone may download and read the paper for non-commerical use. In addition, the article may be reused and quoted provided that the original published version is cited. These conditions allow for maximum use and exposure of the work, while ensuring that the authors receive proper credit. However, author has to sign a form agreeing to the publication of their article under the CC BY-NC license. Fonte: Southern Journal of Research (SJR) <https://sjr.isp.edu.pk/index.php/journal/Policy>. Acesso em: 28 set. 2022.-
Palavras-chave: dc.subjectIsoconversional method-
Palavras-chave: dc.subjectVanadium ore-
Palavras-chave: dc.subjectReduction by hydrogen-
Palavras-chave: dc.subjectNATURAL SCIENCES::Chemistry::Physical chemistry::Kinetics-
Título: dc.titleReduction by hydrogen of the waste rock minerals constituents of a vanadium ore.-
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