Grinding Assistance in the Transformation of Gibbsite to Corundum

After gibbsite was milled for 5 min in a Cr-steel oscillating mill, corundum was obtained by heating the powder for 3 h at 800 °C. We found that iron contamination, produced by the milling process, is essential to attain the transformation at this low temperature and is located at the surface of the...

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Autores principales: Torres Sánchez, Rosa María, Boix, A., Mercader, Roberto Carlos
Formato: Articulo
Lenguaje:Inglés
Publicado: 2002
Materias:
Química
Física
gibbsite
corundum
iron contamination
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/136992
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-136992
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Química
Física
gibbsite
corundum
iron contamination
spellingShingle Química
Física
gibbsite
corundum
iron contamination
Torres Sánchez, Rosa María
Boix, A.
Mercader, Roberto Carlos
Grinding Assistance in the Transformation of Gibbsite to Corundum
topic_facet Química
Física
gibbsite
corundum
iron contamination
description After gibbsite was milled for 5 min in a Cr-steel oscillating mill, corundum was obtained by heating the powder for 3 h at 800 °C. We found that iron contamination, produced by the milling process, is essential to attain the transformation at this low temperature and is located at the surface of the gibbsite particles. The knowledge of the oxidation state and location of the contaminant elements, necessary to control the solid-state reactions and/or phase transformations induced by the milling, was realized in this work by a characterization performed by chemical analysis, x-ray photoelectron spectroscopy, Mossbauer spectroscopy, and isoelectric point determination. The iron contamination amounted to about 3% (as Fe₂O₃) for the sample milled for 60 min. That the iron contamination that occurred mainly on the gibbsite amorphous surface was concluded after a comparison of the isoelectric point determination of the milled samples with that of a mechanical mixture of gibbsite and hematite. X-ray diffraction studies showed that gibbsite looses its crystallinity after the first 5 min of milling.
format Articulo
Articulo
author Torres Sánchez, Rosa María
Boix, A.
Mercader, Roberto Carlos
author_facet Torres Sánchez, Rosa María
Boix, A.
Mercader, Roberto Carlos
author_sort Torres Sánchez, Rosa María
title Grinding Assistance in the Transformation of Gibbsite to Corundum
title_short Grinding Assistance in the Transformation of Gibbsite to Corundum
title_full Grinding Assistance in the Transformation of Gibbsite to Corundum
title_fullStr Grinding Assistance in the Transformation of Gibbsite to Corundum
title_full_unstemmed Grinding Assistance in the Transformation of Gibbsite to Corundum
title_sort grinding assistance in the transformation of gibbsite to corundum
publishDate 2002
url http://sedici.unlp.edu.ar/handle/10915/136992
work_keys_str_mv AT torressanchezrosamaria grindingassistanceinthetransformationofgibbsitetocorundum
AT boixa grindingassistanceinthetransformationofgibbsitetocorundum
AT mercaderrobertocarlos grindingassistanceinthetransformationofgibbsitetocorundum
bdutipo_str Repositorios
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