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Sintering inhibition and oil-absorption properties of calcined coal-series kaolin

Published online by Cambridge University Press:  18 April 2023

Jiaquan Li
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Zhiwei Huang
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Qian Wang
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Fengnian Zhang
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Yang Miao*
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Feng Gao
College of Material Science and Engineering, Taiyuan University of Technology, Taiyuan, P.R. China
Corresponding author: Yang Miao; Email:


In this study, aluminium fluoride trihydrate (AlF3⋅3H2O) was used to inhibit the sintering of calcined coal-series kaolin (CCSK). In addition, the oil absorption properties of CCSK were studied. The particle-size distribution, specific surface area and porosity of the samples were investigated as a function of calcination temperature and the addition of AlF3⋅3H2O. Moreover, the ability of AlF3⋅3H2O to improve the oil absorption of CCSK was explored. The morphology, structure and phase composition of the specimens were investigated using scanning electron microscopy and X-ray diffraction. The phase transition during heating of the samples was studied using thermogravimetric analysis. The preparation with 10 wt.% AlF3⋅3H2O had the optimal sintering inhibition effect on CCSK at 1000°C. The release of SiF4 gas during heating and the formation of mullite whiskers on the particle surface caused by AlF3⋅3H2O moderated the formation of molten-phase liquid bridges between particles and inhibited sintering of the raw material powder. Furthermore, the formation of submicron mullite whiskers on the surface of the CCSK particles enhanced the oil-absorption properties of the sample significantly.

Copyright © The Author(s), 2023. Published by Cambridge University Press on behalf of The Mineralogical Society of the United Kingdom and Ireland

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Contributed equally to this work and should be considered co-first authors

editor: George Christidis


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