Investigation of use of investment casting waste sand in production of wall tile, porcelain tile and opaque glaze

Recycling has gained great importance today in order to protect the environment and contribute to the economy. In this thesis, the valuable components contained in the ceramic pieces that emerge as waste material as a result of the investment casting process were used. It is aimed to reduce raw material consumption and obtain better or the same physical and mechanical properties. In the study, certain amounts of clay, kaolin or zirconia were removed from the bodies of wall tiles, porcelain tiles and opaque glazed tiles, and precision casting waste sand, used in the production of three different types of steel, was added instead. Density, water absorption, dry shrinkage, firing shrinkage, dry strength, firing strength, color and brightness values of the samples were compared. XRD, XRF and microstructure analyzes were performed. In the studies carried out within the porcelain tile; An average 27% decrease in body sludge viscosity was observed. If the viscosity of the body sludge is high, air gap errors occur in the body. An average of 6% increase in the firing strength value of the tile was observed. High strength is an important quality criterion for porcelain tile bodies. In the studies carried out within the wall tiles; The whiteness value (L*) in the color values of the tile bodies to which investment casting waste sand was added was higher than the reference due to the zirconia crystal phase coming from the waste and lower porosity. With the addition of waste, the density, firing shrinkage and strength values of the wall tile bodies increased, while the water absorption decreased. In the studies carried out within opaque glaze; Reducing zirconium dioxide, which has a high density value compared to other compounds, by 5% caused a decrease in the density and viscosity of the glaze mud. However, the same values as the reference were obtained in terms of surface abrasion resistance, linear thermal expansion, heat shock resistance, color and gloss, which are important quality criteria for opaque glaze. The use of valuable raw materials has been reduced in accordance with the purpose.