Kinetics of Dehydroxylation and Decarburization of Coal Series Kaolinite during Calcination: A Novel Kinetic Method Based on Gaseous Products

The analysis of gaseous products reveals the characteristics, mechanisms, and kinetic equations describing the dehydroxylation and decarburization in coal series kaolinite. The results show that the dehydroxylation of coal series kaolinite arises from the calcination of kaolinite and boehmite within the temperature range of 350-850 degrees C. The activation energy for dehydroxylation is 182.71 kJ center dot mol(-1), and the mechanism conforms to the A2/3 model. Decarburization is a two-step reaction, occurring as a result of the combustion of carbon and the decomposition of a small amount of calcite. The temperature range in the first step is 350-550 degrees C, and in the second is 580-830 degrees C. The first step decarburization reaction conforms to the A2/3 mechanism function, and the activation energy is 160.94 kJ center dot mol(-1). The second step decarburization reaction follows the B3 mechanism function, wherein the activation energy is 215.47 kJ center dot mol(-1). A comparison with the traditional methods proves that the kinetics method utilizing TG-FTIR-MS is feasible.