Influence of raw materials and forming technique in the manufacture of stoneware ceramic

Abstract

Clay-rich materials and limestone from mines close to the metropolitan area of Cucuta together with materials obtained after firing process of ceramic products (chamotte) were used to form samples of ceramic tiles using ex­trusion and pressing. Once the ceramic process was finished (with firing temperatures between 1050 °C and 1250 °C), the effect of different ceramic pastes on technological characteristics, such as mechanical resistance to flexion, deep abrasion and percentage of water absorption, was evaluated according to the Colombian technical standard. Samples were characterized using X-ray diffraction, X-ray fluorescence and scanning electron microscopy to iden­tify effects caused by presence of raw materials and the type of molding used. The results show that mineralogical composition and forming technique have an impact on the technological properties of the resulting material. Also it can be seen that for mixtures of raw materials employed in the study, the extrusion technique allows faster glassy phase formation, however this molding technique could be one of the reason for faster recrystallization at high tem­peratures. The best values for the technological properties were found at temperature of 1150 °C.