In this study, the effect of alkaline oxides (MgO, CaO, Na2O and K2O) was investigated in porcelain tile compositions. Talc (MgO) and dolomitic clay (CaO, MgO) were added to porcelain tile compositions instead of feldspar (Na2O, K2O). In the experiments 21 × 32 mixed-level factorial design was used, the individual effects of three main factors and their interactions were determined. The effect of the amount of talc (0, 2, 4 wt. %), dolomitic clay (0, 2, 4 wt. %) and firing conditions (1, 2) on porcelain tile properties were examined. Firing shrinkage, water absorption and the strength of samples were studied by means of factorial design. The porosity and bulk density of samples, color measurement and SEM analyses of these samples were also investigated. It was found that the strength increased and water absorption decreased by means of alkaline oxides variation in the porcelain tile body. According to factorial design, it has been found that the amount of dolomitic clay and talc are the main factors affecting the strength, firing shrinkage and water absorption values. It appeared that the magnitude of these properties were dependent on the amount of alkaline-earth oxides (CaO, MgO).

Keywords: Experimental design, Porcelain tile, Talc, Dolomitic clay