Effect of Zinc-Containing Dust on the Thermal Behavior and Kinetics of Coal–Dust Briquettes During Co-coking Process

The effect of zinc-containing dust on the thermal behavior and kinetics of coal–dust briquettes (CDB) in coking process was studied by thermogravimetric analysis. The coking briquettes with different temperature gradients were characterized by SEM, XRD, CT, IR, and Raman. The results show that with the increase of the proportion of zinc-containing dust, the interaction between zinc-containing dust and pulverized coal in the middle and late stages is continuously enhanced. At 500 °C to 850 °C, the addition of zinc-containing dust will hinder the pyrolysis of coal powder. After 850 °C, it will promote the pyrolysis of coal powder. After 907 °C, Zn began to gasify and hinder the polycondensation of coal. The whole process of coal dust reduction: ZnFe₂O₄–ZnO, Fe₂O₃–FeO₂–Fe, Zn. The kinetic fitting results show that compared with the first stage and the second stage of coal powder, the speed control link of CDB pyrolysis changed from chemical reaction control to diffusion control and nucleation and nuclear growth control. With the increase of temperature, the height of microcrystalline accumulation in CDB coke increases, the degree of dehydrogenation condensation and graphitization of the surface aromatic structure is enhanced, increased degree of ordering, and the active point or defect position is reduced.