THE EFFECT OF SHAPING AND FIRING TECHNOLOGY ON THE PROPERTIES OF CERAMIC TILES BASED ON TWO DIFFERENT KAOLINIC CLAYS

摘要

Two types of different kaolinic clays currently used in a Czech refractory and the ceramic-tile industry in particular, with different ratios between the main non-plastic (quartz) and the main plastic components (kaolinite), were tested for their applicability in the production of ceramic bodies by dry pressing and extruding from a plastic body. Depending on different firing cycles (fast and slow firing processes) at 1090-1170 °C, the opportunities for using both clays for dry pressing and moulding from a plastic body were documented. Fired bodies made from a plastic body have a lower porosity than dry-pressed bodies after the utilization of the same firing cycle. Plastic moulding is not a very suitable technology for fast firing due to the fact that the test samples are more inclined to bloating during the fast-firing process. According to the theoretical models using the pore-size distribution, dry-pressed bodies have a higher probability of frost resistance than the moulded bodies.