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Coatings 2018, 8(1), 30; https://doi.org/10.3390/coatings8010030

Formation of Phases and Porous System in the Product of Hydrothermal Treatment of χ-Al2O3

1
Alexander Butlerov Institute of Chemistry, Kazan Federal University, Kazan 420008, Russia
2
Institute of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Harbin 150080, China
*
Author to whom correspondence should be addressed.
Received: 7 November 2017 / Revised: 26 December 2017 / Accepted: 9 January 2018 / Published: 11 January 2018
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Abstract

The presence of χ-Al2O3 resulting from thermal decomposition gibbsite as part of alumina catalysts is unfavorable because of its acid characteristics. One of the available techniques of χ-Al2O3 removal is crystallization under hydrothermal conditions into boehmite, which is a main precursor of active γ-Al2O3. The influence of products of the hydrothermal treatment of χ-Al2O3 obtaining in result of thermal decomposition gibbsite under T = 150–200 °C, P = 0.5–1.5 MPa and pH = 4.0–9.2 were studied. The hydrothermal treatment products in these conditions are gibbsite and boehmite phases which are formed coincidently by parallel ways. In the alkaline medium at pH = 8.0–9.2 three-dimensional parallelepiped boehmite crystals with the edge length > 200 nm are formed, at pH = 4.0 two-dimensional rhombic-shaped plates with thickness 20–100 nm and with the edge length ~ 80–500 nm are formed. Crystallization of coarse boehmite particles promotes the formation of large and closed mesoporous. View Full-Text
Keywords: alumina; boehmite; gibbsite; hydrothermal treatment alumina; boehmite; gibbsite; hydrothermal treatment
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Egorova, S.R.; Mukhamed’yarova, A.N.; Nesterova, O.V.; Zhang, Y.; Skibina, J.D.; Lamberov, A.A. Formation of Phases and Porous System in the Product of Hydrothermal Treatment of χ-Al2O3. Coatings 2018, 8, 30.

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