Thermal Decomposition Reaction Kinetics of Hematite Ore

In order to understand the thermal decomposition kinetics of hematite particles in inert atmosphere, thermogravimetriy was employed for isoconversional analysis. The kinetic triplet was estimated from the experimental data and the isothermal reaction kinetics was predicted. The results indicated that the thermal decomposition could be divided into two stages, of which the activation energies were 636 kJ/mol and 325 kJ/mol, respectively. The exponential form of pre-exponential factor, In(A/s(-1)), for the two stages were estimated to be 42.9 +/- 6.6 and 14.1 +/- 3.08. At last, the kinetic mechanism of the first stage was suggested to match Sestak-Berggren model as f(alpha)=(1 - alpha)(1.38). The relatively slow reaction rate of the second stage was due to the slag formation during the reaction.