Method for synthesizing molecular sieve by modified kaolin

Abstract

The invention discloses a method for synthesizing a molecular sieve by modified kaolin. The method comprises the following steps of: dividing the raw powder of kaolin into two parts, roasting one part of raw powder of kaolin at the temperature of between 300 and 600 DEG C for 1 to 5 hours to obtain roasted soil, performing acid treatment on the obtained roasted soil, filtrating, washing and drying, and then roasting at the temperature of between 700 and 900 DEG C for 1 to 5 hours to obtain secondary roasted soil; roasting the other part of raw powder of kaolin at the temperature of between 920 and 1,050 DEG C to obtain kaolin; and mixing the secondary roasted soil and the kaolin in a weight ratio of 5:1-1:5 to prepare the synthetic raw materials, crystallizing the synthetic raw materials to obtain the products containing an NaY molecular sieve. By the method, the kaolin is properly modified, and the NaY molecular sieve is synthesized in situ by the modified kaolin, so that the NaY molecular sieve content of the crystallized products is improved.

Description

technical field [0001] The invention belongs to the field of molecular sieve synthesis, and specifically relates to a method for synthesizing NaY molecular sieves by using kaolin as a raw material through modification treatment. Background technique [0002] The usual method for preparing NaY molecular sieves is to synthesize them using an alkaline silica-alumina gel system. Generally, the raw materials used are sodium silicate, aluminum sulfate, sodium metaaluminate, and guiding agent as raw materials. In this way, the synthetic molecular sieve has the characteristics of high molecular sieve content and high silicon-aluminum ratio. Different modification methods can be used to make the modified molecular sieve have multiple properties. characteristics of the response. [0003] In the field of catalytic cracking, NaY molecular sieves are still the most important source of active components, especially the in-situ synthesis of kaolin is an important technology for the prepar...

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Problems solved by technology

[0006] USP4493902 describes the technology of synthesizing crystallized products with high zeolite content containing partial soil and high soil and seed crystals in the same microsphere, the crystallization product crystallinity is higher than 40%, but the raw materials used for spray molding are very demanding in this technology High, use superfine high soil and superfine original soil ASP~600, this kind of superfine soil is expensive, and it is not easy to buy in the market

[0007] In the above method, the synthesis of molecular sieves is carried out after the kaolin is spray-molded into microspheres. When preparing the catalyst, the modulation flexibility of the components is poor.

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