Method capable of reducing crystal grain size of aluminum phosphate molecular sieve

Abstract

The invention discloses a method capable of reducing a crystal grain size of an aluminum phosphate molecular sieve. The method comprises the steps of adding a seed crystal into a crystallization liquid and performing secondary hydrothermal crystallization. Specifically, the method comprises the following steps: uniformly mixing a silicon source, an aluminum source, a phosphorus source, a phosphorus-aluminum molecular sieve capable of being used as a seed crystal, a metal salt solution, and water or a crystallization mother liquid obtained after a seed crystal is prepared, and mixing the mixedsolution and an organic amine templating agent R to prepare an initial gel crystallization solution; and putting the crystallization solution into a hydrothermal synthesis kettle, performing crystallization, and performing separation to obtain a small-particle-size molecular sieve. The method provided by the invention is simple and high-efficiency, and can prepare the small-particle-size molecularsieve with a crystal grain size reduced by at least 50% or more in at least one dimension without using an expensive tetraethylammonium hydroxide organic amine templating agent, and has universality.

Description

technical field [0001] The invention relates to the field of preparation methods of molecular sieve materials, in particular to a preparation method for reducing the grain size of aluminum phosphate molecular sieves. Background technique [0002] In 1982, United Carbide Corporation (UCC) successfully developed a series of aluminum phosphate molecular sieves, known as the third generation molecular sieves. This type of molecular sieve has a regular pore structure and good thermal and hydrothermal stability. At the same time, by introducing heteroatoms into the framework of the molecular sieve to replace Al or P atoms, the acidity modulation of the molecular sieve can be realized, thereby broadening its range. Application in petrochemical, coal chemical and other processes. At present, this type of molecular sieve has been widely used as catalyst, adsorbent and catalyst carrier, and has been highly valued by the field of material science research and industry at home and abro...

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Problems solved by technology

[0009] In the preparation of the above-mentioned small-grain aluminum phosphate molecular sieve, there are problems such as high raw material cost, complex synthesis process, and low yield, which are not conducive to the actual production and application of the product. Therefore, a simple, efficient, and low-cost method is sought. , and a new method for preparing aluminum phosphate molecular sieves that can improve catalytic performance is of great significance

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