Production method of large primary crystal 13X molecular sieve

Abstract

The invention relates to a production method of a large primary crystal 13X molecular sieve, and belongs to the technical field of molecular sieve preparation. The method comprises the following steps: mixing water glass with a sodium aluminate solution under a set temperature condition to obtain gel; adding a seed crystal into the gel, and carrying out first-stage crystallization to obtain a first-stage crystallization solution; performing second-stage crystallization on the first-stage crystallization solution to obtain a second-stage crystallization solution; and respectively separating, washing and drying the second-stage crystallization liquid to obtain the 13X molecular sieve product with the original crystal size of 3-4 microns. The technical problem of increasing the original crystal size of the 13X molecular sieve is successfully solved by finely regulating and controlling a plurality of key steps such as gel preparation, seed crystal introduction, segmented crystallization and post-treatment. According to the technical scheme, the adsorption performance and the bulk density of the molecular sieve are improved, and a new thought and method are provided for industrial production of the molecular sieve.

Claims

1. A method for producing large-crystal 13X molecular sieve, the method comprising: Under set temperature conditions, water glass and sodium aluminate solution are mixed to obtain a gel; adding seed crystals to the gel to perform a stage of crystallization to obtain a stage of crystallization liquid; subjecting the first-stage crystallization solution to second-stage crystallization to obtain a second-stage crystallization solution; The second-stage crystallization liquid is separated, washed and dried respectively to obtain a 13X molecular sieve product with an original crystal size of 3 μm to 4 μm.

2. The method according to claim 1, characterized in that In the water glass, the mass concentration of SiO2 is 360g / L to 380g / L, and the mass concentration of Na2O is 105g / L to 120g / L.

3. The method according to claim 1, characterized in that In the sodium aluminate solution, the mass concentration of Al2O3 is 45g / L to 55g / L, and the mass concentration of Na2O is 70g / L to 80g / L.

4. The method according to claim 1, wherein The set temperature is 30°C to 40°C.

5. The method according to claim 1, characterized in that In the gel, the molar ratio of SiO2 to Al2O3 is 2.7-3.2, the molar ratio of Na2O to Al2O3 is 2.6-3.3, and the molar ratio of H2O to Al2O3 is 130-160.

6. The method according to claim 1, characterized in that The added volume of the seed crystals is 0.05‰ to 0.1‰ of the volume of the gel.

7. The method according to claim 1, characterized in that The temperature of the one-stage crystallization is 70° C. to 80° C., and the time of the one-stage crystallization is 14 hours to 20 hours.

8. The method according to claim 1, characterized in that The temperature of the second stage crystallization is 90° C. to 100° C., and the time of the second stage crystallization is 3 hours to 8 hours.

9. The method according to claim 1, characterized in that The seed crystal is a mixture of high alkali diluted solution and water glass.

10. The method according to claim 9, characterized in that The high alkali dilution solution meets the following requirements: the mass concentration of Al2O3 is 25g / L~31g / L, and αk is 13~15; the water glass meets the following requirements: the mass concentration of SiO2 is 180g / L~200g / L.

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