Mechanisms of Phase and Microstructure Formation during the Cooling of “Fe₂O₃”–CaO–SiO₂–Al₂O₃ Melts in Air and Implications for Iron Ore Sintering

• Nicol Stuart

  Pyrometallurgy Innovation Centre (PYROSEARCH), School of Chemical Engineering, The University of Queensland

• Cheng Siyu

  Pyrometallurgy Innovation Centre (PYROSEARCH), School of Chemical Engineering, The University of Queensland

• Jak Evgueni

  Pyrometallurgy Innovation Centre (PYROSEARCH), School of Chemical Engineering, The University of Queensland

• Hayes Peter Charles

  Pyrometallurgy Innovation Centre (PYROSEARCH), School of Chemical Engineering, The University of Queensland

抄録

Experimental studies have been undertaken on the controlled solidification of iron oxide-rich melts in the system “Fe₂O₃”–CaO–SiO₂–Al₂O₃ in air to determine the mechanisms of phase and microstructure formation during the cooling. Selected bulk compositions, containing approximately 2 wt% Al₂O₃ and CaO/SiO₂ = 3.5, were cooled at a fixed rate of 2K/s from fully liquid melts. The samples were rapidly quenched from selected temperatures, and the microstructures and phases present were examined using scanning electron microscopy (SEM) and electron probe X-ray microanalysis (EPMA). It has been shown that, on non-equilibrium cooling in air, the magnetite and hematite phases are retained to sub-solidus temperatures despite the presence of the pseudo-ternary peritectic reaction H + L → SFCA + L that would occur under equilibrium cooling. The SFCA and SFC-I phases appear to nucleate preferentially at the interfaces between the magnetite and liquid phases; this phenomenon appears to be associated with common crystallographic features in the magnetite and the SFCA phases. It has also been shown that rapid formation of secondary hematite can take place through the liquid phase assisted oxidation of the primary magnetite grains. The mechanism of this reaction has not been previously reported.

収録刊行物

• ＩＳＩＪ　Ｉｎｔｅｒｎａｔｉｏｎａｌ

  ＩＳＩＪ　Ｉｎｔｅｒｎａｔｉｏｎａｌ 60 (12), 2659-2668, 2020-12-15

  一般社団法人 日本鉄鋼協会

キーワード

• Iron ore sinter
• microstructure
• SFC
• SFC-I
• SFCA
• secondary hematite
• magnetite
• solidification
• “Fe₂O₃”–CaO–SiO₂–Al₂O₃
• nucleation
• oxidation
• SEM
• EPMA

詳細情報

• CRID: 1390849931313659392
• NII論文ID: 130007956948
• DOI: 10.2355/isijinternational.isijint-2020-182
• ISSN: 13475460
• ISSN: 09151559
• Web Site: https://www.jstage.jst.go.jp/article/isijinternational/60/12/60_ISIJINT-2020-182/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可