Influences of quartz and muscovite on the formation of mullite from kaolinite

Abstract A kaolin containing muscovite and quartz (K-SZ) and a pure kaolin (K-SX) with the addition of potassium feldspar, K 2 SO 4 and quartz, respectively, were used to investigate the influences of muscovite and quartz on the formation of mullite from kaolinite in the temperature range 1000–1500 °C. In K-SZ formation of mullite began at 1100 °C, and in K-SX at 1000 °C. In K-SZ quartz accelerated the formation of cristobalite and restrained the reaction of mullite and silica. Muscovite in K-SZ acted as a fluxing agent for silica and mullite before 1400 °C and accelerated the formation of cristobalite. The FTIR band at 896.8 cm − 1 was used to monitor the formation of orthorhombic mullite.