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Effect of Na2O on Viscosity, Structure and Crystallization of CaF2–CaO–Al2O3–MgO–TiO2 Slag in Electroslag Remelting

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Abstract

The effect of Na2O on the viscosity, structure, and crystallization behavior of CaF2–CaO–Al2O3–MgO–TiO2 slag was studied using the rotating cylinder method, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction analyses. The analyses demonstrated that with increasing Na2O content, the viscosity and melting temperature of the slag decreased; however, the crystallization temperature increased. Na2O acted as a network modifier to decrease the degree of polymerization in the titanoaluminate structure and consequently increased the mobility of ions in the slag structure. The network structures in the [AlOnF4 – n]-tetrahedral complexes and [AlO4]-tetrahedra are depolymerized with the addition of Na2O; however, the depolymerization had a minimal effect on the Ti–O stretching vibration. During the continuous cooling process of the slag without Na2O, the crystalline phases of 11CaO·7Al2O3·CaF2 were dominant, followed by CaF2 and CaTiO3. In addition to the first three phases, a new precipitated phase of NaAlO2 was observed in the slag when Na2O was added, and the sequence of crystallized precipitation during the continuous cooling process was 11CaO·7Al2O3·CaF2, CaF2, CaTiO3, and NaAlO2. The effective activation energy of 11CaO·7Al2O3·CaF2 increased with increase in Na2O content (0–3.9 wt %) and reached a maximum; however, a further increase in Na2O content (6.6 wt %) decreased the effective activation energy of 11CaO·7Al2O3·CaF2.

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REFERENCES

  1. Shi, C.B., Deoxidation of electroslag remelting (ESR)—a review, ISIJ Int., 2020, vol. 60, pp. 1083–1096. https://doi.org/10.2355/isijinternational.ISIJINT-2019-661

    Article  CAS  Google Scholar 

  2. Ju, J.T., Yang, K.S., Zhu, Z.H., and Gu, Y., Effect of CaF2 and CaO/Al2O3 on viscosity and structure of TiO2-bearing slag for electroslag, J. Iron Steel Res. Int., 2021, vol. 28, pp. 1541–1550. https://doi.org/10.1007/s42243-021-00683-2

    Article  CAS  Google Scholar 

  3. Arh, B., Podgornik, B., and Burja, J., Electroslag remelting: A process overview, Mater. Technol., 2016, vol. 50, pp. 971–979. https://doi.org/10.17222/mit.2016.108

    Article  Google Scholar 

  4. Xiong, Y.L., Song, Z.W., Wang, A.G., and Lou, Y.C., Factors influencing power consumption and power-saving measures in ESR process, China Foundry, 2019, vol. 16, pp. 1–7. https://doi.org/10.1007/s41230-019-8135-5

    Article  Google Scholar 

  5. Shi, C.B., Huang, Y., Zhang, J.X., Li, J., and Zheng, X., Review on desulfurization in electroslag remelting, Int. J. Miner., Metall. Mater., 2021, vol. 28, pp. 18–29. https://doi.org/10.1007/s12613-020-2075-3

    Article  CAS  Google Scholar 

  6. Zheng, D.L., Li, J., Shi, C.B., and Ju, J.T., Effect of TiO2 on the crystallization behaviour of CaF2–CaO–Al2O3–MgO slag for electroslag remelting of Ti-containing tool steel, Ironmaking Steelmaking, 2016, vol. 45, pp. 135–144. https://doi.org/10.1080/03019233.2016.1248699

    Article  CAS  Google Scholar 

  7. Shi, C.B., Li, J., Cho, J.W., Jiang, F., and Jung, I.H., Effect of SiO2 on the crystallization behaviors and In-mold performance of CaF2–CaO–Al2O3 slag for drawing-ingot-type electroslag remelting, Metall. Mater. Trans. B, 2015, vol. 46, pp. 2110–2120. https://doi.org/10.1007/s11663-015-0402-2

    Article  CAS  Google Scholar 

  8. Li, Q.H., Yang, S.F., Zhang, Y.L., An, Z.Q., and Guo, Z.C., Effect of MgO, Na2O, and B2O3 on the viscosity and structure of Cr2O3-bearing CaO–SiO2–Al2O3 slags, ISIJ Int., 2017, vol. 57, pp. 689–696. https://doi.org/10.2355/isijinternational.ISIJINT-2016-569

    Article  CAS  Google Scholar 

  9. Li, W.L. and Xue, X.X., Effects of Na2O and B2O3 addition on viscosity and electrical conductivity of CaO–Al2O3–MgO–SiO2 system, ISIJ Int., 2018, vol. 58, pp. 1751–1760. https://doi.org/10.2355/isijinternational.ISIJINT-2018-212

    Article  Google Scholar 

  10. Kim, H., Kim, W.H., Park, J.H., and Min, D.J., A study on the effect of Na2O on the viscosity for ironmaking slags, Steel Res. Int., 2010, vol. 81, pp. 17–24. https://doi.org/10.1002/srin.200900118

    Article  CAS  Google Scholar 

  11. Wang, Q., Yang, J.A., Zhang, C., Cai, D.X., Zhang, J.Q., and Ostrovski, O., Effect of CaO/Al2O3 ratio on viscosity and structure of CaO–Al2O3-based fluoride-free mould fluxes, J. Iron Steel Res. Int., 2019, vol. 26, pp. 374–384. https://doi.org/10.1007/S42243-019-00248-4

    Article  CAS  Google Scholar 

  12. Jiang, C.H., Zhang, H.X., Xiong, Z.X., Cheng, S., Li, K.J., Zhang, J.L., Liang, W., Sun, M.M., Wang, Z.M., and Wang, L., Molecular dynamics investigations on the effect of Na2O on the structure and properties of blast furnace slag under different basicity conditions, J. Mol. Liq., 2020, vol. 299, p. 112195. https://doi.org/10.1016/j.molliq.2019.112195

    Article  CAS  Google Scholar 

  13. Ju, J.T., Yang, K.S., Ji, G.H., Zhu, Z.H., and Liu, S.W., Effect of TiO2 on viscosity and structure of low-fluoride CaF2–CaO–Al2O3–MgO–Li2O slag for electroslag remelting, Rare Met. Mater. Eng., 2022, vol. 49, pp. 3676–3682.

    Google Scholar 

  14. Zheng, D.L., Li, J., Shi, C.B., and Ju, J.T., Crystallization characteristics and in-mold performance of electroslag remelting-type TiO2-bearing slag, Metall. Mater. Trans. B, 2019, vol. 50, pp. 1148–1160. https://doi.org/10.1007/s11663-019-01536-w

    Article  CAS  Google Scholar 

  15. Ju, J.T., Ji, G.H., Tang, C.M., and An, J.L., Fluoride evaporation and melting characteristics of CaF2–CaO–Al2O3–MgO–Li2O–(TiO2) slag for electroslag remelting, Steel Res. Int., 2020, vol. 91, p. 2000111. https://doi.org/10.1002/srin.202000111

    Article  CAS  Google Scholar 

  16. Wang, Q., Yang, J., Zhang, J.Q., Ostrovski, O., Zhang, C., and Cai, D.X., Effect of Na2O on properties, structure, and crystallization of CaO–Al2O3-based mold fluxes, Steel Res. Int., 2022, vol. 93, p. 2100193. https://doi.org/10.1002/srin.202100193

    Article  CAS  Google Scholar 

  17. Kim, J.B. and Sohn, I., Influence of TiO2/SiO2 and MnO on the viscosity and structure in the TiO2–MnO–SiO2 welding flux system, J. Non-Cryst. Solids, 2013, vol. 379, pp. 235–243. https://doi.org/10.1016/j.jnoncrysol.2013.08.010

    Article  CAS  Google Scholar 

  18. Zhang, G.H., Chou, K.C., and Mills, K., A structurally based viscosity model for oxide melts, Metall. Mater. Trans. B, 2014, vol. 45, pp. 698–706. https://doi.org/10.1007/s11663-013-9980-z

    Article  CAS  Google Scholar 

  19. Xu, R.Z., Zhang, J.L., Han, W.X., Chang, Z.Y., and Jiao, K.X., Effect of BaO and Na2O on the viscosity and structure of blast furnace slag, Ironmaking Steelmaking, 2018, vol. 47, pp. 168–172. https://doi.org/10.1080/03019233.2018.1498761

    Article  CAS  Google Scholar 

  20. Kim, G.H. and Sohn, I., Influence of Li2O on the viscous behavior of CaO–Al2O3–12 mass % Na2O–12 mass % CaF2 based slags, ISIJ Int., 2012, vol. 52, pp. 68–73. https://doi.org/10.2355/isijinternational.52.68

    Article  CAS  Google Scholar 

  21. Park, J.H., Min, D.J., and Song, H.S., Structural investigation of CaO–Al2O3 and CaO–Al2O3–CaF2 slags via Fourier transform infrared spectra, ISIJ Int., 2002, vol. 42, pp. 38–43. https://doi.org/10.2355/isijinternational.42.38

    Article  CAS  Google Scholar 

  22. Zhang, Y.Y., Coetsee, T., Yang, H.F., Zhao, T., and Wang, C., Structural roles of TiO2 in CaF2–SiO2–CaO–TiO2 submerged arc welding fluxes, Metall. Mater. Trans. B, 2020, vol. 51, pp. 1947–1952. https://doi.org/10.1007/s11663-020-01935-4

    Article  CAS  Google Scholar 

  23. Sohn, I. and Min, D.J., A review of the relationship between viscosity and the structure of calcium-silicate-based slags in ironmaking, Steel Res. Int., 2012, vol. 83, pp. 611–630. https://doi.org/10.1002/srin.201200040

    Article  CAS  Google Scholar 

  24. Li, J., Wang, W.L., Wei, J., Huang, D.Y., and Matsuura, H., A kinetic study of the effect of Na2O on the crystallization behavior of mold fluxes for casting medium carbon steel, ISIJ Int., 2012, vol. 52, pp. 2220–2225. https://doi.org/10.2355/isijinternational.52.2220

    Article  CAS  Google Scholar 

  25. Zheng, D.L., Li, J. and Shi, C.B., Development of low-fluoride slag for electroslag remelting: role of Li2O on the crystallization and evaporation of the slag, ISIJ Int., 2020, vol. 60, pp. 840–847. https://doi.org/10.2355/isijinternational.ISIJINT-2019-575

    Article  CAS  Google Scholar 

  26. Shu, Q.F., Klug, J.L., Medeiros, S.L.S., Heck, N.C., and Liu, Y., Crystallization control for fluorine-free mold fluxes: effect of Na2O content on non-isothermal melt crystallization kinetics, ISIJ Int., 2020, vol. 60, pp. 2425–2435. https://doi.org/10.2355/isijinternational.ISIJINT-2020-132

    Article  CAS  Google Scholar 

  27. Watanabe, T., Hashimoto, H., Hayashi, M., and Nagata, K., Effect of alkali oxides on crystallization in CaO–SiO2–CaF2 glasses, ISIJ Int., 2008, vol. 48, pp. 925–933. https://doi.org/10.2355/isijinternational.48.925

    Article  CAS  Google Scholar 

  28. Xu, R.Z., Zhang, J.L., Han, W.X., Chang, Z.Y., and Jiao, K.X., Effect of BaO and Na2O on the viscosity and structure of blast furnace slag, Ironmaking Steelmaking, 2020, vol. 47, pp. 168–172. https://doi.org/10.1080/03019233.2018.1498761

    Article  CAS  Google Scholar 

  29. Chang, Z.Y., Jiao, K.X., Ning, X.J., and Zhang, J.L., Novel approach to studying influences of Na2O and K2O additions on viscosity and thermodynamic properties of BF slags, Metall. Mater. Trans. B, 2019, vol. 50, pp. 1399–1406. https://doi.org/10.1007/s11663-019-01565-5

    Article  CAS  Google Scholar 

  30. Friedman, H.L., Kinetics of thermal degradation of char-forming plastics from thermogravimetry, J. Polym. Sci., Part C: Polym. Symp., 1964, vol. 6, pp. 183–195. https://doi.org/10.1002/polc.5070060121

    Article  Google Scholar 

  31. Vyazovkin, S. and Sbirrazzuoli, N., Isoconversional analysis of the nonisothermal crystallization of a polymer melt, Macromol. Rapid Commun., 2002, vol. 23, pp. 766–770. https://doi.org/10.1002/1521-3927(20020901)23:13<766::AIMARC766>3.0.CO;2-0

    Article  CAS  Google Scholar 

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ACKNOWLEDGMENTS

This study was funded by the National Natural Science Foundation of China (no. 51774225).

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Authors and Affiliations

  1. School of Metallurgical Engineering, Xi’an University of Architecture and Technology, 710055, Xi’an, China

    Jian-tao Ju, Kang-shuai Yang, Yue Gu & Kun He

  2. Shaanxi Engineering Research Center of Metallurgical, 710055, Xi’an, China

    Jian-tao Ju

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Ju, Jt., Yang, Ks., Gu, Y. et al. Effect of Na2O on Viscosity, Structure and Crystallization of CaF2–CaO–Al2O3–MgO–TiO2 Slag in Electroslag Remelting. Russ. J. Non-ferrous Metals 63, 599–609 (2022). https://doi.org/10.3103/S1067821222060098

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