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


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.



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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

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