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Oxidation Behavior of Direct Reduced Iron Powder During Ball-Milling Treatment.
Qiao Liu1, Zhikai Liang1, Cheng Zhang1
1Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China.
Materials (Basel, Switzerland)
|April 14, 2026
Summary
Wet ball-milling causes direct reduced iron (DRI) powder to reoxidize, especially with longer grinding times and smaller particle sizes. This oxidation impacts its suitability for various industrial applications.
Area of Science:
- Materials Science
- Powder Metallurgy
- Surface Chemistry
Background:
- Direct reduced iron (DRI) powder is crucial for catalysis, adsorption, and electromagnetic materials.
- Reoxidation of DRI powder during processing is a significant challenge, limiting its applications.
Purpose of the Study:
- To investigate the oxidation behavior of DRI powder during wet ball-milling.
- To understand the influence of grinding time and particle size on DRI oxidation.
Main Methods:
- Characterization using chemical phase dissolution, X-ray diffraction (XRD), SEM-EDS, and XPS.
- Analysis of bulk and surface oxidation states of iron.
Main Results:
- Relative oxidation degree (ROD) increased from 6.08% to 26.81% with grinding time (20-40 min).
- Oxidation was more severe in particles < 10 μm.
- XRD showed Fe 0 transformation to Fe 3O 4; XPS revealed surface oxides (Fe 2O 3, Fe 3O 4, Fe(OH) 3, FeOOH).
Conclusions:
- Wet milling significantly promotes DRI powder reoxidation.
- Particle size and mechanical activation are key factors driving reoxidation during wet milling.
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