The objective of this study is to present firstly the preparation of atomically ultra-homogeneous mullite precursors by ultrasonic spray pyrolysis technique and then to investigate the evaluation of mullite formation via calcination temperature and soaking time. At a temperature of as low as 500 oC for 15 days, the temperature was very close to the formation temperature of mullite (477 oC) is energetically possible; the structure of the precursor has been preserved as amorphous. It is possible to obtain single phase of mullite crystals at a temperature of 1000 oC without soaking time, while the crystallization required a temperature of 900 oC for 12 hours.

Keywords: Amorphous, Mullite, Pyrolysis, Crystallization, Calcination.