Effect of Cr2O3 on the Kinetics Mechanism and Microstructure of Pellet During Oxidation Roasting Process

• DOI: 10.1002/srin.202200735
• Publication Date: 2022-12-29T02:09:51Z
• Authors: Jinge Feng; Jue Tang; Mansheng Chu; Zichuan Zhao; Zhenggen Liu; Xiaobin Li; Xindong Wang; Xiaoai Wang
• Keywords: 0211 other engineering and technologies; 02 engineering and technology

The oxidation process of iron ore with different Cr2O3 contents is separated into two stages. The Coats–Redfern method is applied to conduct the kinetic analysis, and the restriction links between stages I and II correspond to diffusion control. The apparent activation energy (E) progressively decreases at all stages as the contents of Cr2O3 increase, which is favorable for improving the oxidation kinetics. The fluctuation amplitudes of E in stages I and II are 5.450 and 16.021 kJ mol−1, respectively. The interaction of Fe2O3 and Cr2O3 during oxidation forms a Fe–Cr solid solution, which loosens the internal structure of the pellet and thus increases the number and diameters of the inner pores. This phenomenon facilitates the internal diffusion of oxygen and lowers its concentration inside and outside the pellet. Therefore, the utilization of chromium‐bearing iron ore should be comprehensively considered in terms of its kinetics and microstructure.