Preparation of porcelain building tiles using “K2O–Na2O” feldspar flux as a modifier agent of low-temperature firing

In this paper, to save energy and reduce consumption in building ceramic process, the low temperature porcelain building tiles were prepared by fast firing process using two kinds of “K2O–Na2O” feldspar with different amounts of alkaline and alkaline earth oxides fluxing agents, Si/Al ratio and melting point. The sintering properties of the samples were evaluated by linear shrinkage, water absorption and bulk density. The crystalline phase and microstructure of the samples were characterized by X-ray diffraction and scanning electron microscope. The results showed that the optimum linear shrinkage of 7.55%, water absorption of 0.03% and bending strength of 78.3–85.8 MPa can be achieved for the sample fired at 1170–1190°C, which is attributed to the effect of the combined “K2O–Na2O” feldspar flux system.