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Metallurgical and Materials Transactions B

, Volume 46, Issue 4, pp 1751–1759 | Cite as

Structure, Growth Process, and Growth Mechanism of Perovskite in High-Titanium-Bearing Blast Furnace Slag

  • Lu Liu
  • Meilong HuEmail author
  • Yuzhou Xu
  • Chenguang Bai
  • Yunhua GanEmail author
Article

Abstract

The isothermal crystallization of perovskite in TiO2-CaO-SiO2-Al2O3-MgO high-titanium-bearing blast furnace slag was observed in situ at 1698 K (1425 °C) using a confocal scanning laser microscope. The dendrite structure of perovskite (CaTiO3) thus obtained showed vividly the primary dendrite trunks and secondary dendrite arms. Furthermore, the dendritic growth of perovskite in liquid slag was clearly observed on line. The results showed that the dendrite arrays in which the primary dendrite trunks observed on slag surface were parallel with each other grew toward the same direction. The secondary dendrite arms grew in the perpendicular direction with the primary trucks and stopped growing when they encounter. The perovskite dendrites showed a linear growth at two stages. The dendrites grew faster at early stage at about 5 to 7 μm/s and grew with a lower growth rate at about 1 to 2 μm/s in later stage. Finally, the growth mechanism of perovskite in melt was analyzed with the solidification theory. Based on the theoretical calculation of equilibrium phases in slag, the initial slag could be considered as a binary component system. One component was perovskite and the other component was the sum of all the other species that did not attend the crystallization of perovskite (included SiO2, Al2O3, and MgO, as well as CaO and TiO2 that were not involved in the solid formation). The formation of perovskite required the diffusion of CaO and TiO2 to the solid/liquid interface and the rejection of the other species from the interface. The solid/liquid equilibrium schematic diagram was made based on the calculation.

Keywords

Perovskite Confocal Scanning Laser Microscope Isothermal Crystallization Blast Furnace Slag Liquid Slag 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgment

Project 51404044 was supported by National Natural Science Foundation of China. Project 20130191110015 was supported by Doctoral Fund.

Supplementary material

Supplementary material 1 (MP4 26241 kb)

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Copyright information

© The Minerals, Metals & Materials Society and ASM International 2015

Authors and Affiliations

  1. 1.College of Materials Science and Engineering Chongqing UniversityChongqingP.R. China
  2. 2.School of Electric PowerSouth China University of TechnologyGuangzhouP.R. China

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