Thermodynamic aspects of steel reoxidation behavior by the ladle slag system of CaO-MgO-SiO{sub 2}-Al{sub 2}O{sub 3}-Fe{sub t}O-MnO-P{sub 2}O{sub 5}

Journal Article · Tue Jun 01 04:00:00 EDT 1999 · Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/s11663-999-0076-8· OSTI ID:364010

Kim, S H; Song, B ^[1]

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1. Pohang Univ. of Science and Technology, Kyungbuk (Korea, Republic of). Dept. of Materials Science and Engineering

The reoxidation behavior of steels by slag in the secondary steelmaking process was addressed by investigating the thermodynamic equilibria between the liquid iron containing Mn and P and CaO-MgO-SiO{sub 2}-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}-MnO-Fe{sub t}O ladle slag at 1873 K. The activity coefficient of Fe{sub t}O shows a maximum value in the vicinity of the basicity ((X{sub CaO} + X{sub MgO} + X{sub MnO})/(X{sub SiO{sub 2}} + X{sub Al{sub 2}O{sub 3}} + XP{sub 2}O{sub 5})) = 2.5 at the specific mole fraction range of Fe{sub t}O, while that of MnO seems to increase gradually with increasing the basicity. However, the values of {gamma}{sub Fe{sub t}O} and {gamma}{sub MnO} showed minima with respect to P{sub 2}O{sub 5} content of slag. In addition, the values of {gamma}{sub Fe{sub t}O} and {gamma}{sub MnO} increased as (pct CaO)/(pct Al{sub 2}O{sub 3}) ratio increased at given SiO{sub 2}, MgO, and P{sub 2}O{sub 5} contents. The conversion equations between the Fe{sub t}O and MnO activities and their calculated activities via regular solution model were derived by the correlation between the measured and calculated activities over the limited ranges of Fe{sub t}O and MnO contents. The regular solution model was used to estimate the oxygen potential in the slag. For MgO saturated slags, a{sub Fe{sub t}O{sub (l)}} = 0.864a{sub FeO{sub (R.S.)}}, a{sub MnO{sub (l)}} = 6.38a{sub MnO{sub (R.S.)}}. For Al{sub 2}O{sub 3} saturated slags, a{sub Fe{sub t}O{sub (l)}} = 2.086a{sub FeO{sub (R.S.)}}, a{sub MnO{sub (l)}} = 14.39a{sub MnO{sub (R.S.)}}.

• OSTI ID: 364010
• Journal Information: Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science Journal Issue: 3 Vol. 30; ISSN MTBSEO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CORRELATIONS
EQUILIBRIUM
LIQUID METALS
MANUFACTURING
OXIDATION
SLAGS
STEELS
THERMODYNAMIC ACTIVITY
THERMODYNAMICS