resumo
The glass system MgO-Al2O3-SiO2-FeOy has been mentioned as possible electrolyte for pyroelectrolysis of iron. This work was focused on the study of crystallization behaviour of the iron-containing Al-Mg-Si-O glass system under laser floating zone (LFZ) to identify expected changes occurring under freeze lining or other high temperature gradients at large industrial scale. Lower iron content and faster fibre growth were found favourable for the formation of isolated iron cations in the glass after cooling. The crystallization process, accompanied with separation of mullite and cordierite-type phases, is strongly affected by the formation of nanosized iron-containing clusters, confirmed by Mossbauer and EPR spectroscopies. LFZ method shows good prospects for studying crystallization/vitrification mechanisms in silicate-based glasses with additions of redox-active cations, by providing flexibility in tuning their oxidation state and attaining frozen-in conditions. (C) 2014 Elsevier B. V. All rights reserved.
palavras-chave
SODIUM-SILICATE GLASSES; ION DOPED MULLITE; X-RAY-DIFFRACTION; MOSSBAUER-SPECTROSCOPY; ALUMINOSILICATE GLASSES; SUPERCONDUCTING FIBERS; MELTS; METAL; MGO-AL2O3-SIO2; OXIDATION
categoria
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering
autores
Ferreira, NM; Kovalevsky, AV; Waerenborgh, JC; Quevedo-Reyes, M; Timopheev, AA; Costa, FM; Frade, JR
nossos autores
Andrei Kavaleuski
Investigador principal
Jorge Ribeiro Frade
Professor(a) Jubilado(a)
Nuno Miguel Freitas Ferreira
Bolseiro de pós-DoutoramentoProjectos
IERO-Iron production by Electrochemical Reduction of its Oxide for high CO2 mitigation (IERO)
agradecimentos
This work was supported by the European Unions Research Fund for Coal and Steel (RFCS) research program, under grant agreement RFSR-CT-2010-00002, and by FCT, Portugal: pos-doc grant - SFRH/BPD/74086/2010 and FCT Investigator 2012 program - grant IF/00302/2012 and PTDC/CTM-CER/114561/2009, PEst-C/CTM/LA0025/2011, PEst-C/CTM/LA0011/2013 projects.