97682 20210118122853.0 TAZ-TFG-2020-5193 spa Herrero Cambra, Guillermo Mineral transformations during bauxitic clays firing process related with physical properties of refractory materials Transformaciones minerales durante el proceso de cocción de arcillas bauxíticas y su relación con propiedades físicas de refractarios Zaragoza Universidad de Zaragoza 2020 by-nc-sa Creative Commons 3.0 http://creativecommons.org/licenses/by-nc-sa/3.0/ This research focuses on the mineral and textural transformations during the firing process (from 1000 to 1300ºC) of a bauxite sample from the Sant Mamet Mountain Range (Lérida). This sample, mainly made of bohemite, iron oxides and kaolinite, was mixed in a 90/10 ratio with a clay from the Escucha Fm, mainly composed by quartz and illite. Both the raw and the fired samples at different temperatures were analyzed by X-ray diffraction, optical and electronic microscopy aswell as geochemically characterized by X-ray fluorescence. Also, their physical<br />properties were determined, including density, linear shrinkage, colour, porosity and point load resistance. The clays were destabilized at 1000º and transformed to mullite but they kept their morphologies at this temperature. At this temperature, Fe and Al oxyhydroxides were destabilized too. At increasing firing temperatures, more mineral phases as quartz and hematite began to destabilize leading to the formation of a vitreous phase, which gave rise to the crystallization of abundant mullite, clearly the most abundant phase at 1200 and 1300ºC. With increasing temperature, mullite composition shows lower Si/Al rate and thus, it is closer to empirical mullite formula. With regard to physical properties, variations in density, linear shrinkage, weight loss, total porosity, average pores size and results in point load test are related to the destabilization of the initial mineral phases, the formation of the vitreous phase and the subsequent crystallization of mullite. Changes in colour are due to the initial crystallization of hematite and its subsequent destabilization.<br /><br /> Graduado en Geología Derechos regulados por licencia Creative Commons Yuste Oliete, Alfonso dir. Universidad de Zaragoza 680726@unizar.es 1770024 http://zaguan.unizar.es/record/97682/files/TAZ-TFG-2020-5193.pdf Memoria (spa) oai:zaguan.unizar.es:97682 driver trabajos-fin-grado deposita:2021-01-18 TAZ TFG CIEN 20201204094957.CREATION_DATE