<p>The shift toward sustainable and low-carbon ironmaking has driven the need for innovative approaches. Key strategies include establishing a circular economy by recycling iron-rich waste (by-products) from steel production and using hydrogen (H<sub>2</sub>) as a clean reducing agent to minimize the CO<sub>2</sub> emissions. Mill scale from hot rolling mills during steelmaking is an attractive industrial waste due to its high iron content (about 72&#xa0;wt.%) in the form of wustite (FeO), hematite (Fe<sub>2</sub>O<sub>3</sub>), and magnetite (Fe<sub>3</sub>O<sub>4</sub>). This study employs a one-step thermo-chemical treatment to partially reduce the mill scale to synthesize iron-iron oxide composites. The direct reduction of mill scale is carried out at 500℃ and 650°C for 90&#xa0;min in flowing H<sub>2</sub> gas. Such partially reduced mill scale powder was then consolidated by spark plasma sintering. Detailed characterizations were carried out using X-ray diffraction, optical microscopy, and scanning electron microscopy of treated and untreated mill scale at various stages of the process, before and after compaction. A discussion of environmentally friendly hydrogen reduction as a process for converting mill scale into useful powder metallurgy steel products is presented.</p>

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Iron-Iron Oxide Composites via Hydrogen Reduction of Mill Scale Followed by Spark Plasma Sintering

  • Anupama Kashyap,
  • Krishnakant Phand,
  • Jagadeesh Neduri,
  • Sai Ramudu Meka

摘要

The shift toward sustainable and low-carbon ironmaking has driven the need for innovative approaches. Key strategies include establishing a circular economy by recycling iron-rich waste (by-products) from steel production and using hydrogen (H2) as a clean reducing agent to minimize the CO2 emissions. Mill scale from hot rolling mills during steelmaking is an attractive industrial waste due to its high iron content (about 72 wt.%) in the form of wustite (FeO), hematite (Fe2O3), and magnetite (Fe3O4). This study employs a one-step thermo-chemical treatment to partially reduce the mill scale to synthesize iron-iron oxide composites. The direct reduction of mill scale is carried out at 500℃ and 650°C for 90 min in flowing H2 gas. Such partially reduced mill scale powder was then consolidated by spark plasma sintering. Detailed characterizations were carried out using X-ray diffraction, optical microscopy, and scanning electron microscopy of treated and untreated mill scale at various stages of the process, before and after compaction. A discussion of environmentally friendly hydrogen reduction as a process for converting mill scale into useful powder metallurgy steel products is presented.