Process for preparing NaY molecular sieve by using synthetic mother liquor

Abstract

The invention relates to a method for preparing NaY molecular sieve by using the synthesis mother liquor, comprising the following steps: 1. adding the aluminium salt solution into the synthesis mother liquor to form a precipitating silicon-aluminium gel, then filtering it to obtain a silicon-aluminium gel filter cake; 2. mixing the silicon-aluminium gel filter cake with the soluble silica resource, aluminium resource and guiding agent evenly, after that, pre-crystallizing it under 30 to 100 degrees centigrade for 0.5 to 30 hours; 3. mixing the pre-crystallized product with the soluble silica resource, aluminium resource to form a crystallization mixture, after that, crystallizing it under 90 to 100 degrees centigrade for 8 to 65 hours, then filtering, washing and drying to obtain a NaY molecular sieve with large crystal grain and large granule. The invention overcomes the bias of the existed techniques by adding the pre-crystallizing step before the conventional crystallizing step to prepare NaY molecular sieve with large crystal grain and large granule, and solves slow filtering rate in post treatment.

Description

technical field [0001] The present invention relates to catalytic cracking catalyst, especially the preparation method of NaY molecular sieve. Background technique [0002] NaY molecular sieves are the main source of active components in catalytic cracking catalysts, and the composition of NaY molecular sieves is (0.9±0.2)Na 2 O:Al 2 o 3 :(3~6)SiO 2 :xH 2 O, where the value of x is generally 1-9. At present, the method for industrially producing Y-type molecular sieve basically adopts the directing agent method (US3639099, US3671191) proposed by Grace Company of the United States. That is to say, the soluble silicon source and aluminum source will be (15-17)Na according to a certain order of addition and composition. 2 O:Al 2 o 3 :(14~16)SiO 2 :(280~360)H 2 The directing agent with O grains smaller than 0.1μm is mixed to form a ratio of (1.8~4)Na 2 O:Al 2 o 3 :(7~12)SiO 2 :(120~350)H 2 The reaction mixture of O then crystallized at about 100 °C. The disadvant...

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Problems solved by technology

[0005] The present invention overcomes the defects of the prior art, adds a pre-crystallization step before the conventional crystallization step in the molecular sieve synthesis process, and solves the problem of molecular sieve crystal grains being small , The problem of small particles and slow filtration rate during continuous exchange water washing not only improves industrial production efficiency, but also can prepare NaY molecular sieves with large grains and large particles

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