A non-isothermal kinetic analysis of processes occurring during thermal treatment of kaolinite is carried out using differential thermal analysis on powder samples with heating rates from 1 to 10°C min~(-1) in static air atmosphere. For the parameterization of dehydroxylation process and crystallization of Al-Si spinel phase from metakaolinite the Kissinger method is used. The determined values of apparent activation energy for the dehydroxylation of kaolinite and formation of Al-Si spinel phase are (163 ± 11) kJ mol~(-1) and (826 ± 16) kJ mol~(-1), respectively. For the dehydroxylation of kaolinite the diffusion controlled growth of a new phase with a decreasing nucleation rate is determined as a mechanism of the process. The results also show that the formation of Al-Si spinel phase from metakaolinite is controlled by grain edge nucleation after saturation.
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