Phase Evolution and Sintering Behavior of Tunisian Kaolin-Based Geomaterials for Ceramic Applications

This study explores the valorization of sustainably sourced Tunisian geomaterials including kaolin, carbonate, granite waste, industrial talc, chert and chamotte for the development of ceramic formulations adapted to specific industrial applications. Three distinct mixtures M1 (87% kaolin and 13% carbonate), M2 (76% kaolin, 21% talc and 3% granite) and M3 (10% kaolin, 85% chamotte and 5% chert) were designed. The initial materials and the phase evolution during sintering up to 1300 °C of the prepared mixtures were carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The evolution of the porosity and the density of the prepared mixtures dependence on the sintering temperature were also determined. The experimental results show that the M1 mixture (rich in gehlenite and anorthite at 1100 °C) could be used for the manufacture of building materials such as bricks and wall tiles, the M2 mixture (rich in cordierite and mullite at 1200 °C) could be used as materials for thermal insulation and the M3 mixture (rich in cristobalite and mullite at 1300 °C) could be used for the manufacture of refractories.