Effects of AlF3 and calcination temperature on preparation of hexagonal-shaped α-Al2O3

WANG Ying; YU Xiao-hua; FENG Pan; YU Shuang-lin; XIE Gang; SHI Hui-xian

doi:10.13374/j.issn2095-9389.2018.10.013

Volume 40 Issue 10

Oct. 2018

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WANG Ying, YU Xiao-hua, FENG Pan, YU Shuang-lin, XIE Gang, SHI Hui-xian. Effects of AlF3 and calcination temperature on preparation of hexagonal-shaped α-Al2O3[J]. Chinese Journal of Engineering, 2018, 40(10): 1251-1258. doi: 10.13374/j.issn2095-9389.2018.10.013

Citation:

WANG Ying, YU Xiao-hua, FENG Pan, YU Shuang-lin, XIE Gang, SHI Hui-xian. Effects of AlF₃ and calcination temperature on preparation of hexagonal-shaped α-Al₂O₃[J]. Chinese Journal of Engineering, 2018, 40(10): 1251-1258. doi: 10.13374/j.issn2095-9389.2018.10.013

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Effects of AlF₃ and calcination temperature on preparation of hexagonal-shaped α-Al₂O₃

doi: 10.13374/j.issn2095-9389.2018.10.013

1) Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2) State Key Laboratory of Common Associated Non-ferrous Metal Resources Pressure Hydrometallurgy Technology, Kunming 650500, China

Received Date: 2017-10-13

Abstract

Abstract

A hexagonal α-Al₂O₃ with good crystallinity and regular morphology was prepared at lower calcination temperature by using boehmite (AlOOH) as precursor and AlF₃ seed as additive.The possible mechanisms were investigated by DSC-TG-MS analysis under the condition of AlF₃ seed coefficient 2%, which indicates that a transition compound (Al-O-F) promotes the nucleation phase transition of α-Al₂O₃ through gas-solid reaction, and releases HF simultaneously. Furthermore, the effects of AlF₃ coefficient and calcination temperature (T) on the phase, morphology, size, and specific surface area were investigated. Results show that light AlF₃ seeds can enhance the crystallinity of α-Al₂O₃. When the AlF₃ coefficient increases from 0.5% to 10%, the hexagonal-shaped structure becomes clear, but its size increases and its specific surface area decreases. Boehmite can completely change into high-crystallinity, hexagonal-shaped α-Al₂O₃ under the best condition of T=850℃, AlF₃ seed coefficient 2%, and constant calcination time of 4 h.
- hexagonal-shaped α-Al₂O₃,
- AlF₃ coefficient,
- DSC-TG-MS analysis,
- mechanism of nucleation,
- calcination temperature

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References(11)

References

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