Mullitization, microstructure and physical properties of mechanically activated andalusite sintered by microwave

In this work, the effects of mechanical activation and microwave heating of andalusite on mullite formation have been investigated. XRD results revealed that andalusite peaks disappeared after 60 h of milling and the peaks of alumina were observed. The formation of mullite from activated and as-received andalusite occurred at 800° and 1250 °C, respectively, while mullitization was completed at 1100° and 1400 °C in the former and latter, respectively. Mullite samples prepared from activated andalusite showed better densification with an elongated morphology.