Influence of scrap glass powders and the maturing process in the unfired state on the body properties of a kaolinitic clay after firing

For the ceramic and brick industry as an energy-intensive sector solutions to diminish the energy consumption are of crucial importance. One possibility to affect the energy consumption of the firing process is the use of sintering aids, e.g. secondary raw materials like scrap glass powders.The knowledge of the mineral and liquid phase formation during firing is a basic requirement to assess the physical properties of the fired body. The impact of the scrap glass powders depends to a great extent on the respective clay composition, but also on both the chemical composition and the degree of preparation of the glass. The present paper discusses phase formations during firing and the resulting body properties, both of which depend significantly on interactions between clay and glass during maturation. A material model for describing the mode of action of scrap glass powders within kaolinitic clays is presented.