Advertisement

Metallurgical and Materials Transactions B

, Volume 50, Issue 5, pp 2095–2110 | Cite as

TTT Diagram of 10 pct CaO-90 pct Fe2O3 in Low-Temperature Region Below 1499 K

  • Yoshiaki KashiwayaEmail author
  • Sota Yanai
Article
  • 108 Downloads

Abstract

The important property of a sinter is its ability to withstand the load in a blast furnace (BF). During the cooling process, many compounds among CaO(C), FeO(W), and Fe2O3(F) precipitate, thereby affecting the quality of the sinter. In a previous study, the compounds that precipitated at a high quenching rate (7600 K/s) were clarified. In this study, a 10 pct CaO-90 pct Fe2O3 sample was melted and held at the desired temperatures from 1 minute to 168 hours using the hot thermocouple (HTC) method. The precipitated compounds were clarified by X-ray diffraction (XRD), while a time-temperature-transformation (TTT) diagram for the 10 pct CaO sample was determined below 1499 K. Unstable compounds (C2W4F9 and WFSS) were precipitated together with CF and F in the low-temperature region below 1428 K (1155 °C). However, the unstable compounds disappeared when the holding time was long. In the temperature region from 1428 K to 1499 K (1155 °C to 1226 °C), the rate of formation of CF2 was low; over a period longer than 168 hours, CF disappeared. Therefore, the reaction, CF + F = CF2, is very slow because the locations of CF and F are separated during precipitation from the melt.

Notes

References

  1. 1.
    Y. Kashiwaya: Metall. Mater. Trans. B, 2017, 48B, pp. 3228-3238, DOI:10.1007/s11663-017-1094-6CrossRefGoogle Scholar
  2. 2.
    B. Phillips and A. Muan: J. Am. Ceram. Soc., 1958, vol. 41, pp. 445–54.CrossRefGoogle Scholar
  3. 3.
    Y. Kashiwaya, C. E. Cicutti, and A. W. Cramb: ISIJ Int., 1998, vol. 38, pp. 357–65.CrossRefGoogle Scholar
  4. 4.
    Y. Kashiwaya, C. E. Cicutti, A. W. Cramb, and K. Ishii: ISIJ Int., 1998, vol. 38, pp. 348–56.CrossRefGoogle Scholar
  5. 5.
    Y. Kashiwaya, T. Nakauchi, P. Khanhson, S. Akiyama, and K. Ishii: ISIJ Int., 2007, vol. 47, pp. 44–52.CrossRefGoogle Scholar
  6. 6.
    A. Semykina, J. Nakano, S. Seetharaman, V. Shatokha, and S. Seetharaman: Mater. Trans. B, 2010, 41B. pp. 940-45, DOI: 10.1007/s11663-010-9392-2.CrossRefGoogle Scholar
  7. 7.
    K. Kojima, K. Nagano, T. Inazumi, K. Takagi, and K. Shinada: Tetsu-to-Hagane, 1969, vol. 55, pp. 669-81.CrossRefGoogle Scholar
  8. 8.
    B. Bergman: J. Am. Ceram. Soc., 1986, vol. 69, pp. 608-11.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2019

Authors and Affiliations

  1. 1.Department of Energy Science and Technology, Graduate School of Energy ScienceKyoto UniversityKyotoJapan
  2. 2.Faculty of EngineeringKyoto UniversityKyotoJapan

Personalised recommendations