Kinetic Analysis of Isothermal Crystallization of Potassium Aluminosilicate Ceramics (Leucite and Kalsilite) from Amorphous Potassium Aluminosilicate Precursors

Kinetics of the isothermal crystallization of tetragonal modification of leucite and hexagonal modification of kalsilite from differently prepared precipitated amorphous aluminosilicate precursors were investigated at three different temperatures. Kinetic analyses of the transformation processes have shown that the crystallization of leucite occurs the same way as the crystallization of kalsilite and follows a pseudo-zero-rate kinetic equation. The apparent activation energies calculated by the Arrhenius equation were 373 kJ/mol for the crystallization of kalsilite and 403 kJ/mol for the crystallization of leucite, which is explained by the different microstructures of the prepared precursors.