Thermodynamic model of dephosphorization of CaO-SiO2-MgO-Al2O3-FeO-P2O5-TiO2 slag system based on IMCT theory

Liu Ran; Liu Yanting; Gao Yanjia; Lan Chenchen; Yan Guangshi; Lü Qing

doi:10.7513/j.issn.1004-7638.2024.04.016

Volume 45 Issue 4

Aug. 2024

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Article Navigation > IRON STEEL VANADIUM TITANIUM > 2024 > 45(4): 113-122

Liu Ran, Liu Yanting, Gao Yanjia, Lan Chenchen, Yan Guangshi, Lü Qing. Thermodynamic model of dephosphorization of CaO-SiO2-MgO-Al2O3-FeO-P2O5-TiO2 slag system based on IMCT theory[J]. IRON STEEL VANADIUM TITANIUM, 2024, 45(4): 113-122. doi: 10.7513/j.issn.1004-7638.2024.04.016

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Liu Ran, Liu Yanting, Gao Yanjia, Lan Chenchen, Yan Guangshi, Lü Qing. Thermodynamic model of dephosphorization of CaO-SiO₂-MgO-Al₂O₃-FeO-P₂O₅-TiO₂ slag system based on IMCT theory[J]. IRON STEEL VANADIUM TITANIUM, 2024, 45(4): 113-122. doi: 10.7513/j.issn.1004-7638.2024.04.016

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Thermodynamic model of dephosphorization of CaO-SiO₂-MgO-Al₂O₃-FeO-P₂O₅-TiO₂ slag system based on IMCT theory

doi: 10.7513/j.issn.1004-7638.2024.04.016

1.
College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063000, Hebei, China
2.
Chengde Iron and Steel Group Co., Ltd., Chengde 067102, Hebei, China

Received Date: 2023-10-31
Publish Date: 2024-08-30

Abstract

Abstract

Based on the theory of ionic-molecular coexistence (IMCT), a seven-component slag phosphorus distribution ratio (L_P) model for CaO-SiO₂-MgO-Al₂O₃-FeO-P₂O₅-TiO₂ was established. This model has been validated in multiple slag systems and has the ability to accurately predict the enrichment behavior of phosphorus. The influence of each component on activity and L_P was further analyzed, and the reasonable slag composition for smelting vanadium-titanium magnetite was summarized through this model. The results show that within the temperature range of 1000 to 1600 °C, as the temperature increases, the activities of FeO, MgO and CaO increase, while those of SiO₂ and Al₂O₃ decrease, with no significant effect on TiO₂. As the basicity increases from 0.92 to 1.32, the activities of CaO and MgO significantly increase, while those of SiO₂ and Al₂O₃ decrease significantly, with a gradual increase in the activity of FeO and a nearly constant activity of TiO₂. As the mass fraction of CaO in the slag increases, the activities of Al₂O₃ and SiO₂ decrease, while those of CaO, MgO and FeO increase. As the mass fraction of SiO₂ in the slag increases, the activities of basic oxides CaO, MgO and FeO decrease, while those of acidic oxides SiO₂, Al₂O₃ and TiO₂ increase. After increasing the mass fraction of MgO in the slag from 4% to 14.5%, the variation law of each component activity is basically the same as that of CaO, but the influence is weaker than that of CaO. After increasing the mass fraction of Al₂O₃, FeO and TiO₂ in the slag, only their own activities significantly increase, with relatively small effects on the activities of other components. As the basicity and FeO mass fraction increase, L_P gradually increases. As the MgO mass fraction increases, L_p first decreases and then increases. As the Al₂O₃ and TiO₂ mass fractions increase, L_P gradually decreases. When the TiO₂ mass fraction is around 10%, the slag composition of CaO (35.5%)-SiO₂ (26%)-MgO (10.2%)-Al₂O₃ (12.5%)-FeO (5%)-TiO₂ is selected, and the [P] in the molten iron can be controlled below 0.01%.
- vanadium titanium magnetite,
- HIsmelt process,
- slag,
- phosphorus ratio,
- thermodynamic model,
- ion and molecule coexistence theory

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References

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