Influence mechanism of Ca-Fe flux on fusibility and crystallization behavior of coal fly ash

WANG Ji; GUO Hanghao; LU Guangjun; QU Yongping; MA Zhibin

doi:10.19906/j.cnki.JFCT.2023050

Volume 52 Issue 1

Jan. 2024

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WANG Ji, GUO Hanghao, LU Guangjun, QU Yongping, MA Zhibin. Influence mechanism of Ca-Fe flux on fusibility and crystallization behavior of coal fly ash[J]. Journal of Fuel Chemistry and Technology, 2024, 52(1): 1-8. doi: 10.19906/j.cnki.JFCT.2023050

Citation:

WANG Ji, GUO Hanghao, LU Guangjun, QU Yongping, MA Zhibin. Influence mechanism of Ca-Fe flux on fusibility and crystallization behavior of coal fly ash[J]. Journal of Fuel Chemistry and Technology, 2024, 52(1): 1-8. doi: 10.19906/j.cnki.JFCT.2023050

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Influence mechanism of Ca-Fe flux on fusibility and crystallization behavior of coal fly ash

doi: 10.19906/j.cnki.JFCT.2023050

WANG Ji^1
,,
GUO Hanghao^2
,,
LU Guangjun^2
,,
QU Yongping^3
,,
MA Zhibin^{2
,
,}

1.
School of Chemistry and Chemical Engineering of North University of China, Taiyuan 030051, China
2.
Institute of Resources and Environmental Engineering of Shanxi University, State Environmental Protection Key Laboratory on Efficient Resource-utilization Techniques of Coal Waste, Taiyuan 030006, China
3.
School of Materials Science and Engineering of North University of China, Taiyuan 030051, China

Funds: The project was supported by the Shanxi Province Science Foundation for Youths (202203021212135), National Natural Science Foundation of China (22078181), Shanxi Province Key Research and Development Program (202102090301004, 202102090301024 and 202102090301025) and Shanxi Province Graduate Innovation Project (2022Y131).

Received Date: 2023-05-18
Accepted Date: 2023-06-13
Rev Recd Date: 2023-06-13

Available Online: 2023-06-27

Publish Date: 2024-01-09

Abstract

Abstract

The preparation of high-strength inorganic fibers by coal fly ash is an important method to achieve its high-value utilization. Due to high content of SiO₂ and Al₂O₃ in coal fly ash, it is necessary that Ca-Fe flux should be added to decrease melting temperature of coal fly ash during homogenization of slag and avoid crystallization behavior during preparation of fibers. In this paper, the influence mechanism of Ca-Fe flux on the fusibility and crystallization behavior of coal fly ash under air atmosphere was investigated. The results show that calcium oxide (CaO) and iron oxide (Fe₂O₃) does not show synergistic fluxing effect on fusibility of coal fly ash under air atmosphere, moreover, the fluxing effect of CaO on fusibility is more obvious than that of Fe₂O₃. At high temperature, Fe₂O₃ cannot react with silicon-aluminum components to form low melting point minerals, while CaO is beneficial to transform refractory mullite into anorthite, which greatly reduces the melting point of fly ash. However, excess CaO (>30%) leads to formation of calcium feldspar, which increases melting point of fly ash obviously. During the cooling process, iron precipitates in the form of hematite while calcium precipitates in the form of anorthite, and the crystallization temperature of hematite is lower than that of anorthite. When content of CaO is 32.46%, the melting point of coal fly ash is the lowest, and there is no crystallization during the cooling process. Therefore, CaO is suitable to adjust fusibility and crystallization behavior of coal fly ash during preparation of inorganic fiber.
- coal fly ash,
- inorganic fiber,
- Ca-Fe flux,
- ash fusion temperature,
- crystallization

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References(21)

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