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Title: | Thermal behaviour of kaolinitic raw materials from San José (Oruro, Bolivia) |
Author: | Alfonso Abella, María Pura Penedo, L.A. Garcia Vallès, Maite Martínez Manent, Salvador Martinez, A. Trujillo, J.E. |
Keywords: | Mineralogia Caolí Bolívia Mineralogy Kaolin Bolivia |
Issue Date: | 1-Feb-2022 |
Publisher: | Springer |
Abstract: | Kaolin is widespread as a result of the alteration in the San José Sn-Ag deposit located in Oruro, Bolivia. This study presents a chemical, mineralogical and thermal characterization of the San José kaolinitic deposit, which is necessary to determine their optimal applications. Mineral phases of these white silty kaolinitic materials were determined by X-ray diffraction (XRD) and are quartz, kaolinite, K-feldspar, muscovite, illite and minor halloysite, dickite, plagioclase, jarosite, rutile, alunite and gypsum. The fraction < 63 µm contains 20-27 mass% of kaolinite. Differential thermal analysis (DTA) shows an endothermic peak at 520 °C associated with the dehydroxylation of kaolinite and an exothermic peak at ~ 980 °C related to the crystallization of mullite. TG curves show a total mass loss up to 1300 °C of about 8 mass%. The dilatometric curves show a shrinkage at about 890 °C produced by the collapse of metakaolinite into a spinel-like structure, and another shrinkage starts at 1010 °C, at the beginning of the sintering, when the spinel-like phase is transformed to mullite and amorphous SiO2. Lightness L* is 80-92, but only the mined materials have b* < 4, suitable for paper filling applications. |
Note: | Reproducció del document publicat a: https://doi.org/10.1007/s10973-022-11245-3 |
It is part of: | Journal of Thermal Analysis and Calorimetry, 2022, vol. 147, num. 9, p. 5413-5421 |
URI: | http://hdl.handle.net/2445/194014 |
Related resource: | https://doi.org/10.1007/s10973-022-11245-3 |
ISSN: | 1388-6150 |
Appears in Collections: | Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada) |
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