Application of oil shale mining by-products as raw materials in the determination of the vitrification curve of red porcelain stoneware tiles by dilatometric method

Oil shale mining by-products were used as raw materials in a ceramic composition containing high amounts of kaolinitic clay materials developed for red stoneware tiles. The vitrification curve and linear shrinkage of the composition were determined by from dilatometry data. The microstructural changes of composition after sintering were analyzed by scanning electron microscopy. Red ceramic tiles were produced at low maximum firing temperature (water absorption < 0.5% at 1050 °C) and high mechanical strength (> 70 N/mm2) using this class of non-conventional raw materials.