Research On Body And Glaze For Low Temperature Fast Single-firing Glazed Roof Tile

Glazed roof tile is one kind of practical construction materials with high technicalperformance and unique style. Therefore it is accepted and used by people universally, andhas bright future. A lot of mineralogical materials would be consumed for making glazed rooftile and the energy consumption in its traditional sintering system is high. Its production costincreases sharply due to markup of raw materials, induced by decrease of high-grade rawmaterials. The glazed roof tile with high performance and low cost could be obtained on theterms of cheap materials and effective sintering system.There is no special requirement on color of body for glazed roof tile, so, the low gradematerials can be taken into use. Coal gangue is an industry solid waste with biggest piled inChina, causing great environment pollution. The coal gangue in Baishan was tested to be theargillaceous coal gangue, which could be used as the main material in body mix for glazed rooftile after having XRD test and chemical analysis. Low temperature fast single-firing hasbecome the new trend of construction ceramics, and the reasonable body mix and glaze mixare the most important elements. Thus, a low temperature fast single-firing body for glazedroof tile was prepared based in CaO-MgO-Al₂O₃-SiO₂quaternary system, taking coal gangueand local materials as the main raw materials, and then a matching glaze mix is also obtained.The results indicate that the optimal body mix is the one containing34%CG,38%Chinastone,6%Bentonite,4%Talc,16%Wollastonite,4%Jilin clay and2%Quartz. The optimalsintering temperature is tested to be1170℃and the sintering system is0℃-80℃at rate of3℃/min,180℃-950℃at rate of7℃/min，keep950℃for8min,950℃-1170℃at rate of5℃/min, keep1170℃for10min.The optimal experiment conditions were also gained afterseries of experiments. The thermal behavior of optimizing body mix was examined by DSC.The body and glaze sintered at different temperatures were examined concerning their phasechange by X-ray diffraction （XRD） and the microstructure for body sintered at differenttemperatures and final product were observed by scanning electron microscopy （SEM）. Theresults show that quartz，anorthite and mullite are the major crystalline phase in the sintered body at1170℃, and wollastonite and quartz in glaze. The body and glaze joined tightly and astratum intermedium in good shape formed between them.The glossiness of the glaze surface is89and the Moh’s hardness is over level6, and thecoefficient of expansion of glaze is6.6×10^-6/℃. The final product has a bending strength of43MPa and water absorption of0.22%. Its frost resistance is excellent and it doesn’t spiltafter15cycles （from-15to20℃）, and its thermal shock resistance is good too and it doesn’tspilt after15cycles （from180to20℃）. All the characteristics meet the national standardJC709-1998and JC/T665-1997.