Abstract:The thermodynamics, kinetics, phase transformation, and microstructure evolution of vanadium-bearing stone coal during suspension roasting were systematically investigated. Thermodynamic calculations showed that the carbon in the stone coal burned and produced CO₂ in sufficient oxygen during roasting. The mass loss of stone coal mainly occurred within the temperature range from 600 to 840 °C, and the thermal decomposition reaction rate increased to the peak at approximately 700 °C. Verified by the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira- Sunose (KAS) methods, the thermal decomposition reaction of stone coal was described by the Ginstling-Brounshtein equation. The apparent activation energy and pre-exponential factors were 136.09 kJ/mol and 12.40 s^-1, respectively. The illite in stone coal lost hydroxyl groups and produced dehydrated illite at 650 °C, and the structure of sericite was gradually destroyed. The surface of stone coal became rough and irregular as the temperature increased. Severe sintering occurred at the roasting temperature of 850 °C.

Key words: vanadium-bearing stone coal; thermodynamics; thermal decomposition kinetics; phase transformation; microstructure evolution