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The present work focuses on the mineralogical analysis of sedimentary clay material samples collected from deposits located in the Campos dos Goytacazes-RJ (Brazil) region. These samples are representative and widely used by the ceramic plants in production of bricks and roofing tiles. The samples were selected with the objective of analyzing their characteristics regarding chemical composition, loss on ignition, X-ray diffraction, morphology, particle size, plasticity and thermal analysis. The sedimentary red clays have low amount of SiO 2 , high amount of Al 2 O 3 , and high loss on ignition. In addition, it was found that the character of the clays is typically kaolinitic. ResumoO presente trabalho é focado sobre a análise mineralógica de amostras de argilas sedimentares coletadas de depósitos localizados na região de Campos dos Goytacazes-RJ (Brasil). Estas amostras são representativas e largamente usadas na produção de blocos cerâmicos e telhas. As amostras foram selecionadas com o intuito de analisar suas características com respeito à composição química, perda ao fogo, difração de raios X, morfologia, análise de tamanho de partícula, plasticidade e análise térmica. As argilas vermelhas sedimentares têm baixa quantidade de SiO 2 , alta quantidade de Al 2 O 3 e alta perda ao fogo. Além disso, foi determinado que o caráter das argilas é tipicamente caulinítico. Palavras-chave: argilas sedimentares, mineralogia, minerais industriais.Cerâmica 51 (2005) ) 381-386

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Large quantities of eggshell waste are discarded in the food processing industry. This work investigates the incorporation of eggshell waste as a raw material into a wall tile body, replacing natural carbonate material by up to 15 wt%. Formulations containing eggshell were uniaxially dry pressed and fired at 1150°C using a fast-firing cycle. Physico-mechanical properties of the fired tiles (e.g. linear shrinkage, water absorption, apparent density, flexural strength) were then determined. Development of the microstructure was followed by scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses. The results showed that eggshell waste could be used in wall tiles, in the range 5–10 wt%, as a partial replacement for traditional carbonate-based materials with only a slight decrease in the end product properties.

In this work the use of "thin" red clay from south-eastern Brazil (Campos dos Goytacazes, RJ) as raw material for the manufacture of wall tile was investigated. A wide range of characterization techniques was employed, including X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), grain-size analysis, and thermogravimetric analysis. The wall tile body was prepared by the dry process. The tile pieces were uniaxially pressed and fired between 1080 -1180 ºC using a fast-firing cycle. The following technological properties were determined: linear shrinkage, water absorption, apparent density, and flexural strength. The development of the microstructure was followed by SEM and XRD analyses. It was found that the "thin" red clay is kaolinitic type containing a substantial amount of quartz. The results also showed that the "thin" red clay could be used in the manufacture of wall tiles, as they present properties compatible with those specified for class BIII of ISO 13006 standard.