Effects of Aluminium Oxide Content on the Regenerated Magnesia-Calcium Bricks for Cement Rotary Kiln

Regenerated magnesia-calcium brick samples with different aluminium oxide (Al2O3) contents were prepared using spent magnesia-calcium bricks and fused magnesia as the main raw materials and Al2O3 powders as the additive. The phase compositions, microstructures, room temperature, hot flexural strengt...

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Bibliographic Details
Published in:Processes 2023-10, Vol.11 (10), p.3018
Main Authors: Qiu, Gui-Bo, Hao, Yi-Dang, Hou, Jia, Wang, Hui-Gang, Zhang, Xuan-Hao, Peng, Ben, Zhang, Mei
Format: Article
Language:English
Subjects:
Aluminum compounds
Aluminum oxide
Bricks
Bulk density
Calcium
Calcium aluminate
Carbonate minerals
Cement
Clinker
Coatings
Corrosion
Corrosion resistance
Environmental impact
Flexural strength
Glycerol
Hydration
Investigations
Kilns
Liquid phases
Magnesium compounds
Melting points
Molybdenum
Particle size
Phase composition
Protective coatings
Raw materials
Reagents
Room temperature
Sinterability
Test methods
Tricalcium aluminate
Tricalcium aluminum ferrite
Wettability
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Summary:Regenerated magnesia-calcium brick samples with different aluminium oxide (Al2O3) contents were prepared using spent magnesia-calcium bricks and fused magnesia as the main raw materials and Al2O3 powders as the additive. The phase compositions, microstructures, room temperature, hot flexural strength, and kiln coating adherence of the regenerated samples were investigated. This indicates that the Al2O3 content increased, mainly resulting in the content of tetracalcium aluminoferrite (C4AF) and tricalcium aluminate (C3A) increasing in the regenerated samples. The bulk density, room temperature flexural strength, and kiln coating adherence all increased, whereas the hot flexural strength and corrosion resistance to cement clinker both deteriorated with an increase in the Al2O3 content. This was because, on the one hand, the low melting point phases of C4AF and C3A improved the sinterability of the regenerated samples during the burning stage, and on the other hand, they melted or existed in the liquid phase at the experimental temperature, which degraded the hot flexural strength and corrosion resistance but enhanced the kiln coating adherence as the wettability of the liquid phase. The content of Al2O3 in the regenerated magnesia-calcium brick should not be higher than 1.1 wt.%, considering its comprehensive performance for cement rotary kiln.
ISSN:2227-9717
2227-9717
DOI:10.3390/pr11103018