Firing transformations and properties of tiles from a clay from Burkina Faso

A clay from Burkina Faso consisting of poorly crystallised kaolinite (66 mass %), illite (10 mass %) and quartz (13 mass %) was used in the production of tiles. The changes during the sintering process were investigated by X-ray diffraction (XRD), dilatometric measurements and scanning electron microscopy (SEM). Mainly metakaolinite, Al-spinel and mullite were formed when the temperature increased to 1100 °C. The tiles formed at 1100 °C had an acceptable flexural strength value (27.3 MPa), a slightly high water absorption value (16.9%) and a linear shrinkage value of 2.5% at 1100 °C. Because of its high water absorption value, the clay should be amended with sand, feldspar and talc as fluxing agents to obtain the required tile performances.