Effect of Mechanical Activation on the Kinetics of Kyanite Mullitization
The kinetics of mullitization of kyanite samples, both initial and mechanically activated in high-energy grinding devices within temperature range 1273-1573 K was investigated. It was shown that the kinetics of kyanite mullitization formally corresponds to the equation of monomolecular decomposition. The activation energy of this transformation is (630±10) kJ/mol. It was established that mechanical activation of kyanite accelerates mullitization processes during subsequent thermal treatment. The yield of mullite per unit surface area is almost two times higher for mechanically activated sample than for non-activated one. Possible mechanism of mullitization process and technological aspects of the implementation of this process in industry are discussed.