Effect of firing temperature on sintering of cordierite-mullite refractories from raw materials and Narathiwat clay in Thailand

Abstract

Cordierite-Mullite is a refractory material produced by a fast firing process of kaolinitic clay (33%), quartz (62%) and talc (5%). This research aimed to study the effect of firing temperature on sintering of cordierite-mullite refractories from raw materials and Narathiwat clay in Thailand. An electric kiln was used to sintering took place temperature was 1300°C. Soaking temperature took for 1 hour. Then, they were characterized by physical properties, chemical analysis by X-ray fluorescence (XRF), phase change by X-ray diffraction (XRD), thermal changing of clay cordierite-mullite body by scanning electron microscopy (SEM). The results showed that raw refractories material can be used for the experiment. It was sintered at temperature of 1300°C and showed the phase of mullite and quartz. NRT specimens showed water absorption of 4.16% with bulk density of 2.27 g/cm3, apparent porosity of 9.2% after firing at 1300°C. This firing temperature, the flexural strength in NRT clay reached the highest value of 330.82 kg/cm3. The evidence indicated that the vitrification is completed.