This paper investigates the kinetic characteristics of sponge iron powder reoxidation under two different oxidation atmospheres by examining the reoxidation process from thermodynamic, microstructural, and kinetic perspectives. It reveals the changes in the surface microstructure and oxide content of sponge iron under different
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This paper investigates the kinetic characteristics of sponge iron powder reoxidation under two different oxidation atmospheres by examining the reoxidation process from thermodynamic, microstructural, and kinetic perspectives. It reveals the changes in the surface microstructure and oxide content of sponge iron under different oxidation conditions. The results indicate that the thermodynamic conditions for the formation of Fe
2O
3 were more relaxed than those for Fe
3O
4. As the oxidation time increased, the surface microstructure of the sponge iron transitioned from a porous granular form (Fe) to a dense blocky structure (Fe
3O
4), eventually forming a rod-like product (Fe
2O
3). Under an atmosphere of O
2/Ar = 21/79, the oxide content was significantly higher compared to an atmosphere of O
2/Ar = 11/89. Under an atmosphere of O
2/Ar = 11/89, the oxidation rate index (
n) remained at 0.68 throughout all stages, indicating a consistently higher oxidation rate. Conversely, under an atmosphere of O
2/Ar = 21/79, the initial oxidation rate index (
n1) was 1.17, reflecting a slower initial oxidation rate, while in the final stage, the oxidation rate index (
n2) dripped to 0.33, indicating a substantial increase in the oxidation rate. The research results provide basic research ideas and references for an in-depth study of the antioxidant storage of sponge iron.
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