Thermal behaviours of clay mixtures during brick firing: A combined study of in-situ XRD, TGA and thermal dilatometry

The mineralogical transformation of clay material is critical to the firing process for brick manufacturing. In this study, a series in-situ integrated techniques are used study properties two mixtures routinely production bricks at local factory in Queensland, Australia. In-situ XRD, thermal expansion/contraction, weight loss, and microstructural evolution bodies high temperature have been investigated. Illite/mica persists until 950 °C during process, while K-feldspar transforms into plagioclase with addition Ca cations from starting materials. A slower ramp rate decreases onset many reactions, including decomposition calcite nucleation/crystallisation mullite. An increase 1150 has significantly enhanced compressive strength prepared buttons. addition, six length changing steps identified across range 30 °C. contraction kaolinite between about 420 850 might compensate expansion typical bricks, may minimise potential failure ?- ?-quartz inversion. However, rapid shrinkage metakaolin above increases risk cracking manufactured bricks.