Thermodynamic properties of manganese oxide in BOF slags

Sung Mo Jung, Chang Hee Rhee, Dong Joon Min

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28 Citations (Scopus)


It is necessary to understand the thermodynamic properties of MnO in steelmaking slags for the smelting reduction of Mn ore in BOF process. Studies of the manganese distribution between CaO-SiO2-FetO-MnO slags and liquid silver in equilibrium with solid Fe in the temperature range of 1 623 to 1 723 K were carried out under a CO/CO2 atmosphere. The FetO content in (32.4∼36.3)%CaO-(31.6∼44.0)%SiO2- (9.9∼24.1)%FeO-(0.4∼2.6)%Fe2O3-(8.9∼10.8)% MnO slags was found to have a linear relationship with oxygen partial pressure. The values of Fe3+/Fe2+ in the same slag system increase by increasing the FetO content. The Mn distribution ratio between slag and metal, (%MnO)/[%MN]Fe-Csat, increases with FeO content in a linear relationship over the measured FeO concentration range (6.7-24.1 mass%). The Mn distribution ratio decreases with increasing CaF2, which is believed to have the effect of increasing the activities of MnO and FeO. Temperature dependence of equilibrium manganese distribution at pO2 = 6.6 × 10-12 atm in the temperature range of 1 623 to 1 723 K can be expressed as follows: log (MnO)/[%Mn]Fe-Csat = 14 270/T - 6.55 The relative partial heat of solution of MnO into (32.7∼39.1) %CaO-(32.7∼38.8)%SiO2-(10.2∼20.2∼20.78)%FeO- (1.0∼2.4)%Fe2O3-(9.4∼10.8)%-MnO slags was estimated to be 198 kJ/mol.

Original languageEnglish
Pages (from-to)63-70
Number of pages8
JournalISIJ International
Issue number1
Publication statusPublished - 2002

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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