Clays are raw materials with properties that are necessary for the manufacture of ceramic tiles. The characteristics of clay ceramic raw materials may vary within the same mineral deposit. Clay blending promotes better use of clay reserves, thereby increasing the applicability and life cycle of raw materials. Therefore, it is important to understand the mechanisms controlling the firing of ceramic tiles. In this study, three different clays from a clay deposit were assessed and ten formulations were prepared using the mixture design method. The formulations were analysed using differential thermal and thermogravimetric analyses and dilatometric analysis. Subsequently, the most refractory and fluxing formulations were subjected to thermal tests under various heating rates, similar to the process used for the calculation of apparent sintering activation energy for the densification of clays and for pyroplasticity tests. It is suggested that a mineral deposit can be assessed based on activation energy and thermal kinetics, expanding the alternatives available to the miner through the planning of mixtures with various clays and thus reducing the energy costs of the industrial process.

No abstract

Raw materials with different technological properties found in the same geological region can constitute a ceramic formulation upon proper mixing. This study aims to demonstrate the best way to develop a mixture using a mixture design method, emphasizing the geology of three clays in the Rio Bonito Formation/Paraná Basin. The mineralogical and chemical characteristics of these clays were investigated by X‐ray diffraction and X‐ray fluorescence, respectively, along with elementary (CNH), differential thermal and thermogravimetric analysis, and dilatometry. Ten formulations and their technological properties, including apparent density, shrinkage, water absorption, and mechanical resistance, were investigated. The results showed the potential of the studied mineral deposit clays for application in the ceramic industry in different materials. Clay 1 showed refractory characteristics, and Clay 3 was more plastic. The mixtures with higher contents of Clay 1 showed ideal for monoporosa tile recipes. The mixtures with higher contents of Clay 3 were ideal for porcelain tile pastes.