Specific Features of Formation of Crystalline Silicoaluminophosphates in Grains Based on Kaolin and Phosphoric Acid

Transformations of granules based on kaolin and phosphoric acid under the conditions of vapor-phase crystallization at 170°C were studied. Specific features of the individual and cooperative action of a water vapor and a template dipropylamine on the granules were determined. It is shown that the re...

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Published inRussian journal of applied chemistry Vol. 91; no. 6; pp. 948 - 958
Main Authors Bok, T. O., Knyazeva, E. E., Ivanova, I. I.
Format Journal Article
LanguageEnglish
Published Moscow Pleiades Publishing 01.06.2018
Springer Nature B.V
Subjects
Berlinite
Catalysis
Chemical composition
Chemistry
Chemistry and Materials Science
Chemistry/Food Science
Cristobalite
Crystal structure
Crystallinity
Crystallization
Granular materials
Hydroxyethyl celluloses
Industrial Chemistry/Chemical Engineering
Kaolin
Morphology
Nanospheres
Organic chemistry
Phosphoric acid
Silicoaluminophosphates
Transport
Tridymite
Water vapor
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Summary:Transformations of granules based on kaolin and phosphoric acid under the conditions of vapor-phase crystallization at 170°C were studied. Specific features of the individual and cooperative action of a water vapor and a template dipropylamine on the granules were determined. It is shown that the regulation of competing processes of formation of dense non-porous phases (tridymite, cristobalite, berlinite) and microporous crystalline silicoaluminophosphates of structural types ATL and ATN can be carried out by creating transport pores in the volume of the initial granules. The formation of transport pores was provided by using of porogens (hydroxyethyl cellulose and carbon nanospheres) with the subsequent calcination of the granules. The presence of 40- and 60- nm macropores in the porous structure favored intensification of mass-exchange processes occurring within the granules under the vapor-phase crystallization conditions. This led to an increase in the selectivity of crystallization of the materials with crystal structure types AEL and ATN. The morphology of the crystals with the AEL and ATN structure and their chemical composition depend on the porogen used to prepare the starting granules.
ISSN:1070-4272
1608-3296
DOI:10.1134/S1070427218060113