Gas release during clay firing and evolution of ceramic properties

Gas release, crystalline structure and ceramic properties were analysed during firing of clay raw materials and extruded bricks. Carbon monoxide, carbon dioxide, nitrogen oxides, and methane emissions were measured during the firing cycle. Ammonia and sulphur dioxide were not observed within the detection limits. The evolution of crystalline phases, open porosity, volumetric shrinkage, rupture tension and apparent density were correlated to the amount of gases produced at different temperatures, ranging from 300 to 1200 °C. These results can be applied for optimising the production process.