Table 2.1 lists the combustion char

Table 2.1 lists the combustion characteristic parameters of all coal gangue samples. From the table, it can be seen that the peak temperature (Tp) of coal gangue is in the range of 450-530S ℃, which is higher than that of coal (about 406-418 ℃). So compared with coal combustion, the entire pyrolysis process of coal gangue is delayed. Table 2.1 also shows that the properties of the raw materials affect the ignition and burnout performance of coal gangue. The ignition temperature (Ti) of S2, S9 and S10 is higher than the ignition temperature of S3 and S11, which is related to the content of volatile matter in coal gangue, because the content of volatile matter affects the number of oxygen-containing functional groups and changes in chemical structure The higher volatile content in S3 and S11 is beneficial to the release process of volatiles. The faster the rate of devolatilization and oxidation of volatiles, the lower the ignition temperature of the particles. However, the change of ignition temperature in the table is not always consistent with the change of volatile matter, which indicates that the ignition temperature may not only be affected by the content of volatile matter, but also by other factors. The ignition performance of coal gangue can be evaluated by the ignition index (Di). For samples S2, S3, S4, S6, S8, and S11, a higher ignition index corresponds to a lower ignition temperature, but samples S1, S5, S7 , S9 and S10 are inconsistent with the above trends, which means that the ignition index may not only be related to the ignition temperature, the ash in coal gangue may have an impact on the ignition performance, because high ash will affect the oxygen diffusion and heat transfer to a certain extent. The high ash content in S1, S5 and S7 (70.8-77%) leads to greater oxygen diffusion resistance and higher temperature gradient inside and outside the particles, which are not conducive to further ignition of the particles. In contrast, the relatively low ash content in S9 and S10 weakens the adverse effect of ash content in coke on its ignition performance. Therefore, the ignition performance of coal gangue is not only related to the ignition humidity, but also to the ash content. It should be pointed out that the results of the burnout performance and the ignition performance are basically consistent, and the delivery and burnout processes are affected by the ignition process.