Role of iron ore in enhancing gasification of iron coke: structural evolution, influence mechanism, and kinetic analysis

The utilization of iron coke provides a green pathway for low-carbon ironmaking. To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification, the effect of iron ore on the microstructure of iron coke was investigated. Furthermore, a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method. The findings indicate that compared to coke, iron coke exhibits an augmentation in micropores and specific surface area, and the micropores further extend and interconnect. This provides more adsorption sites for CO2 molecules during the gasification process, resulting in a reduction in the initial gasification temperature of iron coke. Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke. The metallic iron reduced from iron ore is embedded in the carbon matrix, reducing the orderliness of the carbon structure, which is primarily responsible for the heightened reactivity of the carbon atoms. The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure. Moreover, as the proportion of iron ore increases, the activation energy for the carbon gasification gradually decreases, from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15%.