Reduction of iron oxides in mould fluxes with additions of CaSi2

Min Wang; Rie Endo; Yoshinao Kobayashi; Zuoyong Dou; Masahiro Susa

doi:10.1007/978-3-319-48769-4_39

Reduction of iron oxides in mould fluxes with additions of CaSi₂

Min Wang, Rie Endo, Yoshinao Kobayashi, Zuoyong Dou, Masahiro Susa

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

1 Citation (Scopus)

Abstract

Iron oxides in mould fluxes enhance heat extraction from the molten steel to the mould due to energy absorption by d-d transitions of Fe²⁺ and re-emission. Thus, the existence of iron oxides is against mild cooling of molten steel. In this study, mould flux powders containing ca 2 mass% Fe₂O₃ were mixed with sufficient amounts of CaSi₂. The mixtures were contained in alumina crucibles and melted at 1673 K in Ar-H₂ atmosphere. The melts were poured into brass moulds to obtain glassy samples 5 mm thick. The Fe₂O₃ concentration was analysed by a scanning electron microscope with an energy dispersive spectrometer. The concentration decreased from ca 1.71 mass% to 0.49 mass% within 5 min and then settled down. Mass transfer of Fe₂O₃ is supposed to be the rate-controlling step at high temperature. The mass transfer coefficient has been calculated to be 1.8×10^-3 cm・s^-1, which seems reasonable. Since crystallisation of mould flux enhance heat reflection from the molten steel to reduce heat transfer, crystallisation kinetics of mould fluxes has been investigated using the Avrami equation, which suggests that additions of reducing agents such as CaSi₂ suppress the crystallisation process. In addition, CaSi₂ additions result in a dramatic decrease in the total radiative heat flux across mould fluxes in glassy state and would be effective for mild cooling of molten steel.

Original language	English
Title of host publication	Advances in Molten Slags, Fluxes, and Salts
Subtitle of host publication	Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016
Editors	Ramana G. Reddy, Pinakin Chaubal, P. Chris Pistorius, Uday Pal
Publisher	Springer International Publishing AG
Pages	357-365
Number of pages	9
ISBN (Print)	9783319486253
DOIs	https://doi.org/10.1007/978-3-319-48769-4_39
Publication status	Published - 2017
Externally published	Yes
Event	10th International Conference on Molten Slags, Fluxes and Salts, MOLTEN 2016 - Seattle, United States Duration: 2016 May 22 → 2016 May 25

Publication series

Name	Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016

Conference

Conference	10th International Conference on Molten Slags, Fluxes and Salts, MOLTEN 2016
Country/Territory	United States
City	Seattle
Period	16/5/22 → 16/5/25

Keywords

Calcium silicide
Iron oxide
Mould flux
Reduction

ASJC Scopus subject areas

Mechanical Engineering
Mechanics of Materials
Materials Chemistry
Metals and Alloys

Access to Document

10.1007/978-3-319-48769-4_39

Cite this

Wang, M., Endo, R., Kobayashi, Y., Dou, Z., & Susa, M. (2017). Reduction of iron oxides in mould fluxes with additions of CaSi₂. In R. G. Reddy, P. Chaubal, P. C. Pistorius, & U. Pal (Eds.), Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016 (pp. 357-365). (Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016). Springer International Publishing AG. https://doi.org/10.1007/978-3-319-48769-4_39

Reduction of iron oxides in mould fluxes with additions of CaSi₂. / Wang, Min; Endo, Rie; Kobayashi, Yoshinao et al.

Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016. ed. / Ramana G. Reddy; Pinakin Chaubal; P. Chris Pistorius; Uday Pal. Springer International Publishing AG, 2017. p. 357-365 (Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Wang, M, Endo, R, Kobayashi, Y, Dou, Z & Susa, M 2017, Reduction of iron oxides in mould fluxes with additions of CaSi₂. in RG Reddy, P Chaubal, PC Pistorius & U Pal (eds), Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016. Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016, Springer International Publishing AG, pp. 357-365, 10th International Conference on Molten Slags, Fluxes and Salts, MOLTEN 2016, Seattle, United States, 16/5/22. https://doi.org/10.1007/978-3-319-48769-4_39

Wang M, Endo R, Kobayashi Y, Dou Z, Susa M. Reduction of iron oxides in mould fluxes with additions of CaSi₂. In Reddy RG, Chaubal P, Pistorius PC, Pal U, editors, Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016. Springer International Publishing AG. 2017. p. 357-365. (Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016). doi: 10.1007/978-3-319-48769-4_39

Wang, Min ; Endo, Rie ; Kobayashi, Yoshinao et al. / Reduction of iron oxides in mould fluxes with additions of CaSi₂. Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016. editor / Ramana G. Reddy ; Pinakin Chaubal ; P. Chris Pistorius ; Uday Pal. Springer International Publishing AG, 2017. pp. 357-365 (Advances in Molten Slags, Fluxes, and Salts: Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016).

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abstract = "Iron oxides in mould fluxes enhance heat extraction from the molten steel to the mould due to energy absorption by d-d transitions of Fe2+ and re-emission. Thus, the existence of iron oxides is against mild cooling of molten steel. In this study, mould flux powders containing ca 2 mass% Fe2O3 were mixed with sufficient amounts of CaSi2. The mixtures were contained in alumina crucibles and melted at 1673 K in Ar-H2 atmosphere. The melts were poured into brass moulds to obtain glassy samples 5 mm thick. The Fe2O3 concentration was analysed by a scanning electron microscope with an energy dispersive spectrometer. The concentration decreased from ca 1.71 mass% to 0.49 mass% within 5 min and then settled down. Mass transfer of Fe2O3 is supposed to be the rate-controlling step at high temperature. The mass transfer coefficient has been calculated to be 1.8×10-3 cm・s-1, which seems reasonable. Since crystallisation of mould flux enhance heat reflection from the molten steel to reduce heat transfer, crystallisation kinetics of mould fluxes has been investigated using the Avrami equation, which suggests that additions of reducing agents such as CaSi2 suppress the crystallisation process. In addition, CaSi2 additions result in a dramatic decrease in the total radiative heat flux across mould fluxes in glassy state and would be effective for mild cooling of molten steel.",

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AB - Iron oxides in mould fluxes enhance heat extraction from the molten steel to the mould due to energy absorption by d-d transitions of Fe2+ and re-emission. Thus, the existence of iron oxides is against mild cooling of molten steel. In this study, mould flux powders containing ca 2 mass% Fe2O3 were mixed with sufficient amounts of CaSi2. The mixtures were contained in alumina crucibles and melted at 1673 K in Ar-H2 atmosphere. The melts were poured into brass moulds to obtain glassy samples 5 mm thick. The Fe2O3 concentration was analysed by a scanning electron microscope with an energy dispersive spectrometer. The concentration decreased from ca 1.71 mass% to 0.49 mass% within 5 min and then settled down. Mass transfer of Fe2O3 is supposed to be the rate-controlling step at high temperature. The mass transfer coefficient has been calculated to be 1.8×10-3 cm・s-1, which seems reasonable. Since crystallisation of mould flux enhance heat reflection from the molten steel to reduce heat transfer, crystallisation kinetics of mould fluxes has been investigated using the Avrami equation, which suggests that additions of reducing agents such as CaSi2 suppress the crystallisation process. In addition, CaSi2 additions result in a dramatic decrease in the total radiative heat flux across mould fluxes in glassy state and would be effective for mild cooling of molten steel.

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