DEGEO - Departamento de Geologia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/8

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2006 - 20072

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Autor: search.filters.author.Sousa, Daniel José Lima deAssunto: search.filters.subject.Kaolinite

Resultados da Pesquisa

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    Mineralogical, micromorphological and geochemical evolution of the kaolin facies deposit from the Capim region (northern Brazil).
    (2007) Sousa, Daniel José Lima de; Varajão, Angélica Fortes Drummond Chicarino; Jacques, Yvon; Costa, Geraldo Magela da
    The Capim Kaolin District (eastern Brazilian Amazon), is one of the largest kaolin deposits in the world; with the kaolin used mainly for paper coating. The kaolin developed at the expense of Cretaceous sandy-clayey sediments of the Ipixuna formation, through intense lateritization from the Mesozoic to Cenozoic times. This work describes the morphological, mineralogical, crystallochemical and geochemical evolution of the Capim kaolin facies. Based on the profile analysis in the open pit fronts, it encompasses X-ray diffraction, thin-section optical analysis, EDS-assisted scanning electron microscopy and transmission electron microscopy, chemical analysis, infrared and Mo¨ssbauer spectroscopies. Six facies were defined as different stages of the supergene process. Ferruginization led to a thick duricrust on the soft kaolin, which in turn evolved from sandy-clayey sediments of the Ipixuna Formation. A subsequent deferruginization event degraded the duricrust, resulting in the flint kaolin facies.
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    Geochemical evolution of the capim river kaolin, northern Brazil.
    (2006) Sousa, Daniel José Lima de; Varajão, Angélica Fortes Drummond Chicarino; Yvon, Jacques
    The Capim River kaolin, located in the eastern Brazilian Amazon, constitutes one of the most important kaolin deposits in the world. Known for its high whiteness, its noble application is in the paper industry. Studies were carried out on samples from the six facies of the deposit (sand kaolin, soft kaolin, lower transition facies, ferruginous crust, upper transition facies and flint kaolin) in order to trace its geochemical evolution. The kaolin developed at the expense of Cretaceous sandy–clayey sediments of the Ipixuna Formation. Intense lateritic processes characterized by ferruginization and deferruginization mechanisms led to the distinction of the different facies.