Study on the thermal kinetics of anthracite oxidation induced by water and associated pyrite

Abstract

Pyrite and water in coal have considerable influence on coal spontaneous combustion and threaten the safety of mine production gravely. To reveal the influence mechanism of water and associated pyrite on oxidation kinetics of coal–oxygen composite reaction, the pyrite of 0%, 1%, 2%, 4%, 6% and the moisture of 1%, 5%, 10%, 15% and 20% were mixed with the coal samples to obtain 25 coal samples. Thermogravimetric analysis technology was conducted to explore the changes of mass and characteristic temperatures of coal samples treated with water and associated pyrite during the low–temperature oxidation, and kinetic analysis of the oxidation process was discussed based on multiple heating rates(5 °C/min, 10 °C/min and15 °C/min).The results show that water and associated pyrite had a great influence on coal in oxygen absorption and weight gain stage ( T 3 ~ T 5 ), and there was a proportion range with the largest synergistic oxidation contribution. The apparent activation energy of the coal sample appeared changes, but the mechanism model did not, indicating that water and pyrite could affect the oxidation process of the coal sample externally. When water and associated pyrite exhibit synergistic interaction, there have a range that water was 10~15% and associate pyrite was 2~4% had the largest promotion and contribution to anthracite oxidation. The results have important scientific value and practical guiding significance for the further study on prediction, prevention and control of high sulfur anthracite spontaneous combustion.