Evaluation of kinetic parameters from a single TG curve based on the similarity theory and process symmetry

The equation for calculation of the activation energy of the diffusion of the evolved products through the matrix (E) from a single TG curve were proposed by solving Fick's laws. The solution is based on the similarly theory by utilizing a Fourier number.The proposed method was examined by using mass loss data for the dehydroxylation of some micas with and without FeO (muscovite and its varieties and lepidolite) as determined from their TG curves. TheE values for the first stage of the dehydroxylation of these micas areE ₁,=85±10 kJ mol^–1; for the final stageE ₂=380±40 kJ mol^–1 and for the mass loss connected with fluorineE _F=85±10 kJ mol^–1.Dedicated to Prof. Menachem Steinberg on the occasion of his 65th birthdayPart of this work was carried out in the Institute of Geochemistry of the USSR Academy Science (Irkutsk). I wish to thank Dr. S. B. Brandt for helpful discussions.I am pleased to express my gratitude to Prof. S. Yariv for his important comments.I am grateful to the Ministry of Absorption of the Government of Israel for financial support of this work.