Chemical composition, mineralogical and thermal characterization of clays in a red ceramic pole in ES (Brazil)

The state of Espírito Santo, located in the southeast region of Brazil, has stood out on the national scene in the non-metallic mineral transformation industry for the production of red ceramics. Its main and most important conglomerate of companies in the sector is located in the ceramic hub of São Roque do Canaã, located in the central region of the state, marked by its state pioneering in the red ceramic sector. The present work aims to present the chemical composition, mineralogical and thermal characterization of clays. The clay materials were collected in the ceramic industry yard at the center, then taken to the laboratory. The chemical composition of the materials was carried out using x-ray fluorescence (XRF), the mineralogical characterization was carried out using x-ray diffractometry (XRD), and the thermal characterization was carried out using thermogravimetric analysis (ATG). In general, no significant differences were recorded between the constitutions of the clays, in which the chemical composition mostly consists of oxides of SiO₂, Al₂O₃, Na₂O, TiO₂, K₂O and high levels of Fe₂O₃ which, when purchased together, have relatively similar proportions. The thermogravimetric characterization shows typical behavior of kaolinite clays. As for mineralogical characterizations, they present a similar crystalline structure with sharp and clearly evident peaks, with emphasis on the clay minerals kaolinite and gibbsite. (author)