Abstract: Using thermogravimetric experiments, the kinetic characteristics of magnesite thermal decomposition were investigated under the condition of 10% (vol) CO₂ in the actual production atmosphere of an entrained-flow dynamic roasting furnace. Based on a multi - method collaborative framework, the three kinetic factors in the magnesite thermal decomposition process were systematically calculated through parameter cross - verification between the Hu - Gao - Zhang integral method and the Kissinger differential method. The kinetic mechanism was initially screened by the double equal and double step method and further determined by combining with the Malek maximum probability method. The study revealed that CO₂ in the atmosphere exerts an inhibitory effect on the decomposition of carbonate species within magnesite. Furthermore, the presence of impurities (e.g., calcium carbonate) was found to interfere with the determination of reaction mechanisms via Malek's method at elevated temperatures. The results show that in a 10% (vol) CO₂ atmosphere, the main decomposition temperature of magnesite ranges from 550°C to 650 °C, the average activation energy is 66.00 kJ·mol^-1, the pre-exponential factor is 1.05 × 10⁵ s^-1, and the decomposition process conforms to the random nucleation and growth model.

Key words: Carbon dioxide, Reaction kinetics, Magnesite, Pyrolysis, Thermogravimetry

摘要： Using thermogravimetric experiments, the kinetic characteristics of magnesite thermal decomposition were investigated under the condition of 10% (vol) CO₂ in the actual production atmosphere of an entrained-flow dynamic roasting furnace. Based on a multi - method collaborative framework, the three kinetic factors in the magnesite thermal decomposition process were systematically calculated through parameter cross - verification between the Hu - Gao - Zhang integral method and the Kissinger differential method. The kinetic mechanism was initially screened by the double equal and double step method and further determined by combining with the Malek maximum probability method. The study revealed that CO₂ in the atmosphere exerts an inhibitory effect on the decomposition of carbonate species within magnesite. Furthermore, the presence of impurities (e.g., calcium carbonate) was found to interfere with the determination of reaction mechanisms via Malek's method at elevated temperatures. The results show that in a 10% (vol) CO₂ atmosphere, the main decomposition temperature of magnesite ranges from 550°C to 650 °C, the average activation energy is 66.00 kJ·mol^-1, the pre-exponential factor is 1.05 × 10⁵ s^-1, and the decomposition process conforms to the random nucleation and growth model.

关键词: Carbon dioxide, Reaction kinetics, Magnesite, Pyrolysis, Thermogravimetry