Method for recycling molecular sieve mother solution

Abstract

The invention discloses a method for recycling molecular sieve crystallization mother solution, which comprises the following steps of: (1) preparing a material for synthesizing a molecular sieve, gelatinizing, crystallizing, filtering, and collecting all molecular sieve crystallization mother solution; (2) using the obtained all molecular sieve crystallization mother solution for synthesis of the molecular sieve directly, mixing with a solid silicon source, an aluminum source and alkali, and adding or not adding molecular sieve seed crystals and a template agent to obtain a reaction mixture; and (3) crystallizing the obtained reaction mixture according to the conventional hydrothermal method, obtaining a filter cake, namely a molecular sieve product, and filtering and collecting all molecular sieve crystallization mother solution, wherein the obtained all molecular sieve crystallization mother solution can be circularly utilized according to the sequence of steps (2) and (3). In the synthesis of the molecular sieve, alkaline waste liquor is not discharged basically, the total silicon utilization rate is more than or equal to 90 percent, and the yield of the molecular sieve product is over 90 percent.

Description

technical field [0001] The invention relates to the technical field of molecular sieve synthesis, and more specifically relates to a method for recycling molecular sieve synthesis by using the molecular sieve crystallization mother liquor synthesized by silicon-aluminum molecular sieves. Background technique [0002] Molecular sieves are important catalysts or catalyst active components in petroleum refining and chemical processes. In the prior art, when synthesizing silica-alumina molecular sieves, silicon-containing compounds (water glass, silica sol, and organosilicon ester, etc.), aluminum-containing compounds (hydrated alumina, aluminum salts, etc.), alkalis (sodium hydroxide, potassium hydroxide, etc.) ) and water in an appropriate proportion, adding or not adding an organic template and heating in an autoclave for a certain period of time to obtain molecular sieve crystals. Under alkaline conditions, some silicon will remain in the mother liquor and not be fully util...

AI Technical Summary

Problems solved by technology

If you continue to add more water-containing silicon source, aluminum source or template solution in the molecular sieve synthesis feed, the water-to-silicon ratio of the system will increase, thereby reducing the single-pot yield of molecular sieve synthesis.

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