Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore

Yong-sheng Sun; Yue-xin Han; Yan-feng Li; Yan-jun Li

doi:10.1007/s12613-017-1386-5

Volume 24 Issue 2

Feb. 2017

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2017 > 24(2): 123-129

Yong-sheng Sun, Yue-xin Han, Yan-feng Li, and Yan-jun Li, Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore, Int. J. Miner. Metall. Mater., 24(2017), No. 2, pp. 123-129. https://doi.org/10.1007/s12613-017-1386-5

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Yong-sheng Sun, Yue-xin Han, Yan-feng Li, and Yan-jun Li, Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore, Int. J. Miner. Metall. Mater., 24(2017), No. 2, pp. 123-129. https://doi.org/10.1007/s12613-017-1386-5

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Research Article

Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore

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Corresponding author:
Yong-sheng Sun E-mail: yongshengsun@mail.neu.edu.cn
Received: 13 May 2016; Revised: 23 June 2016; Accepted: 6 July 2016

Abstract

Abstract

To reveal the formation and characteristics of metallic iron grains in coal-based reduction, oolitic iron ore was isothermally reduced in various reduction times at various reduction temperatures. The microstructure and size of the metallic iron phase were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and a Bgrimm process mineralogy analyzer. In the results, the reduced Fe separates from the ore and forms metallic iron protuberances, and then the subsequent reduced Fe diffuses to the protuberances and grows into metallic iron grains. Most of the metallic iron grains exist in the quasi-spherical shape and inlaid in the slag matrix. The cumulative frequency of metallic iron grain size is markedly influenced by both reduction time and temperature. With increasing reduction temperature and time, the grain size of metallic iron obviously increases. According to the classical grain growth equation, the growth kinetic parameters, i.e., time exponent, growth activation energy, and pre-exponential constant, are estimated to be 1.3759 ±0.0374, 103.18 kJ·mol^-1, and 922.05, respectively. Using these calculated parameters, a growth model is established to describe the growth behavior of metallic iron grains.
- iron ore reduction;
- metallic iron;
- grain size;
- growth kinetics;
- activation energy

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