A kind of method utilizing beta molecular sieve mother liquor to synthesize beta molecular sieve

Abstract

The invention discloses a method for synthesizing a beta molecular sieve by utilizing a beta molecular sieve mother solution. The method comprises the following steps: performing equal-pH coprecipitation on a crystallized mother solution and dilute acid parallel flow to synthesize silica gel in bottom water containing a gel accelerator, adding a template-agent-containing BETA molecular sieve milled by a colloid mill to serve as a seed crystal, and performing hydrothermal crystallization to synthesize the BETA molecular sieve according to the ratio of low addition amount of organic template agents. According to the production method disclosed by the invention, the batching amount of a fresh silicon source and the template agent in beta molecular sieve synthesis is reduced, and due to the existence of a molecular sieve microcrystal, the crystallization process of the molecular sieve is accelerated, and the crystallization period is shortened. Moreover, the synthesized beta molecular sieve is high in crystallinity degree, the milled seed crystal contains lots of micro grains and organic template agents with secondary structures, the crystallization induction period can be effectively shortened, and the use amount of the template agent is reduced. Therefore, the synthetic cost is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of molecular sieve synthesis, in particular to a method for synthesizing a beta molecular sieve mother liquor. Background technique [0002] In the process of synthesizing β molecular sieve by hydrothermal method, the template agent plays a guiding role. If the amount of template agent added is small, the initial gel viscosity of the solution is high, and it is difficult to stir, resulting in unstable product quality; some production processes increase the product quality by prolonging the crystallization time. The stability of quality, the crystallization time is usually about 50 hours to 15 days, and the crystallization time is too long, which seriously increases the production cycle of β molecular sieve products. Therefore, in industrial production, a large amount of template agent and excessive silicon source are generally used. Promote the realization of the crystallization process, so the β molecular s...

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Problems solved by technology

[0002] In the process of synthesizing β molecular sieve by hydrothermal method, the template agent plays a guiding role. If the amount of template agent added is small, the initial gel viscosity of the solution is high, and it is difficult to stir, resulting in unstable product quality; some production processes increase the product quality by prolonging the crystallization time. The stability of quality, the crystallization time is usually about 50 hours to 15 days, and the crystallization time is too long, which seriously increases the production cycle of β molecular sieve products. Therefore, in industrial production, a large amount of template agent and excessive silicon source are generally used. Promote the realization of the crystallization process, so the β molecular sieve mother liquor after crystallization contains a large amount of unreacted silicon source and template agent. If the mother liquor is directly discharged, it will not only lead to waste of raw materials, but also lead to COD and COD in water. Ammonia nitrogen NH3-N seriously exceeds the standard, causing pollution to the environment