Nucleation and Growth Mechanism of Iron Grains in Oolitic Hematite Reduced via Microwave Heating

Xin WANG; Ying LEI; Rui LIU; Wen CHEN; Yu LI; Chao YONG; Zhenhong LIAO

doi:10.13779/j.cnki.issn1001-0076.2020.04.007

2020 Vol. 40, No. 4

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Xin WANG, Ying LEI, Rui LIU, Wen CHEN, Yu LI, Chao YONG, Zhenhong LIAO. Nucleation and Growth Mechanism of Iron Grains in Oolitic Hematite Reduced via Microwave Heating[J]. Conservation and Utilization of Mineral Resources, 2020, 40(4): 46-51. doi: 10.13779/j.cnki.issn1001-0076.2020.04.007

Citation:

Xin WANG, Ying LEI, Rui LIU, Wen CHEN, Yu LI, Chao YONG, Zhenhong LIAO. Nucleation and Growth Mechanism of Iron Grains in Oolitic Hematite Reduced via Microwave Heating[J]. Conservation and Utilization of Mineral Resources, 2020, 40(4): 46-51. doi: 10.13779/j.cnki.issn1001-0076.2020.04.007

Nucleation and Growth Mechanism of Iron Grains in Oolitic Hematite Reduced via Microwave Heating

1.
School of Metallurgical Engineering, Anhui University of Technology, Ma'anshan 243032, Anhui, China
2.
Department of Mineral Resources Development and Utilization Technology, Changsha Research Institute of Mining and Metallurgy Co. Ltd., Changsha 410012, Hunan, China

More Information

Corresponding author: Ying LEI, leiyingahut@163.com

Received Date: 09 June 2020

Abstract

Abstract

The nucleation and growth kinetics of iron grains in oolitic hematite coke-bearing pellets reduced by microwave heating were studied by Avrami-Erofeyev model. The phase composition, morphology and grain size, element composition and distribution of reduced sample were analyzed by XRD, SEM and EDX techniques. The results showed that the metallization rate was 77.6~92.6% at 1 173~1 473 K in 20 minutes. The nucleation and growth rate of iron grains in oolitic hematite coke-bearing pellets reduced at 1 173~1 473 K were found well-fitting to the selected model with the corresponding R² coefficient ranges of 0.9411~0.9977 and 0.9484~0.9848, respectively. The kinetic parameters were obtained by fitting. The nucleation activation energy and growth activation energy were given as 51.21 kJ/mol and 18.05 kJ/mol, which indicated that the reduction process was controlled by iron grain nucleation rate. Compared with the conventional heating conducted by previous researchers, it could be found that the nucleation and growth rate of iron grains was faster in microwave field. The analysis of SEM showed that the morphologies of iron grains were spherical and partly vermicular, and the maximum single iron grain size in the field of view was about 10 micrometers.
- oolitic hematite /
- coke-bearing pellet /
- microwave heating /
- iron grain /
- nucleation and growth

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References

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