Preparation method for crystal transformation synthesis of ANA type molecular sieve

Abstract

The invention belongs to the technical field of molecular sieve synthesis, and discloses a preparation method for crystal transformation synthesis of an ANA type molecular sieve. The preparation method comprises the following steps: mixing an inorganic alkali solution with a Y-type molecular sieve, and crystallizing; and sequentially drying and grinding the crystallized product to obtain the ANA type molecular sieve. Through the key guiding effect provided by Na < + > ions in the molecular sieve crystal transformation process, template-free synthesis of the ANA type molecular sieve is realized, and dependence of ANA type molecular sieve synthesis on an organic template agent is eliminated. Besides, the Y-type molecular sieve is used as a silicon-aluminum source, so that the cost is reduced, the production efficiency is improved, the environmental pollution is reduced, and favorable conditions are provided for large-scale production of the ANA type molecular sieve. The prepared ANA type molecular sieve has the advantages of high purity, good crystallinity and price, and fully meets the market demand.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieve synthesis, and in particular to a method for preparing a crystal-transformed synthetic ANA type molecular sieve. Background Art

[0002] ANA molecular sieve is a molecular sieve with an eight-membered ring structure, micropores, and analcime structure. ANA molecular sieve has selective adsorption and heterogeneous catalysis due to its unique structure composed of aluminosilicate skeleton, and is used in many fields. ANA molecular sieve can be used in water purification and remediation of contaminated soil due to its microporous structure characteristics, and can effectively capture and remove toxic heavy metal ions. At the same time, this type of molecular sieve also shows application prospects in the extraction of trace metals.

[0003] At present, there are few reports on the synthesis of small-pore materials such as ANA molecular sieves. The synthesis method of ANA molecular sieves reported so far is mainly based on the traditional hydrothermal synthesis method using organic templates. However, organic templates are not only expensive but also require additional preparation steps, and organic templates are mostly toxic, and their large-scale application is also prone to environmental pollution problems. For example, the Chinese patent application with publication number CN107902670A discloses an ANA molecular sieve with a plug-in type morphology and a preparation method thereof, and an organic template hexadecyltrimethylammonium bromide is introduced in its preparation process; the Chinese patent application with publication number CN103121697A discloses a pure silicon ANA zeolite molecular sieve and a preparation method thereof, and a quaternary ammonium salt organic template is also used in its preparation process, and it can be observed from the electron microscope image that the ANA zeolite molecular sieve prepared by it has a relatively low crystallinity; the Chinese patent application with publication number CN117923513A discloses a MOR and ANA symbiotic molecular sieve and its preparation method and application, and its preparation product is not a pure ANA molecular sieve, and a quaternary ammonium salt organic template is also required. This greatly hinders the widespread application of ANA type molecular sieves.

[0004] Therefore, it is of practical significance to develop an economical, green and highly crystallinity-rich ANA-type molecular sieve synthesis method. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing ANA type molecular sieve by crystallization synthesis, so as to solve the problem that the existing synthesis method of ANA type molecular sieve cannot avoid the use of organic template and the product has low crystallinity.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing ANA type molecular sieve by crystal transformation synthesis, comprising the following steps:

[0008] The inorganic base solution is mixed with the Y-type molecular sieve for crystallization; the crystallized product is dried and ground in sequence to obtain the ANA-type molecular sieve.

[0009] Preferably, in the preparation method, the inorganic base in the inorganic base solution includes sodium hydroxide, and the solvent in the inorganic base solution is water.

[0010] Preferably, in the preparation method, the molar ratio of the inorganic base in the inorganic base solution to the solvent in the inorganic base solution is 0.6-1.4:30-150.

[0011] Preferably, in the preparation method, the Y-type molecular sieve includes one or more of USY-type molecular sieve, HY-type molecular sieve, and NaY-type molecular sieve.

[0012] Preferably, in the preparation method, the molar ratio of the mass of the Y-type molecular sieve to the inorganic base in the inorganic base solution is 60-100 g: 0.8-1 mol.

[0013] Preferably, in the preparation method, the time for mixing the inorganic base solution and the Y-type molecular sieve is 3 to 5.5 hours, and the speed of mixing the inorganic base solution and the Y-type molecular sieve is 800 to 1200 rpm.

[0014] Preferably, in the preparation method, the crystallization temperature is 160 to 260° C., and the crystallization time is 6 to 96 hours.

[0015] Preferably, in the preparation method, the drying temperature is 70 to 95° C., and the drying time is 10 to 18 hours.

[0016] Preferably, in the preparation method, after the grinding, the step further includes: screening through a 200-mesh sieve.

[0017] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention uses Y-type molecular sieves that can be mass-produced industrially as the silicon-aluminum source. Due to the low price and good effect of the raw materials, this choice is more conducive to the large-scale production of ANA-type molecular sieves, which helps to reduce environmental pollution and reduce costs.

[0019] (2) The synthesis method of the present invention is simple, and only requires mixing an inorganic alkali solution with a Y-type molecular sieve for crystallization, filtration, washing, and drying to obtain an ANA-type molecular sieve. + Key guiding role in template-free synthesis of molecular sieves, Na +In the shape-selective synthesis of gel nanostructures, the crystallization result is directed to ANA molecular sieve by gradually forming a crystal-like coordination environment around the cation, thereby successfully avoiding the dependence on organic templates. The ANA molecular sieve synthesized by the preparation method of the present invention has high purity, good crystallinity, high yield, micron-scale grain size, fixed grain morphology as kite-shaped tetrahedron, competitive price, and can meet market demand.

[0020] (3) The one-step crystallization synthesis method provided by the present invention is to disassemble the framework of the original molecular sieve and then combine it into a new molecular sieve. The crystallization synthesis method for preparing molecular sieve materials is generally to use low-cost and easy-to-prepare molecular sieves, and to promote their crystallization into high-value product molecular sieves by adjusting external factors such as reaction temperature, pressure, and inorganic cations. The principle is as follows: Figure 1 Compared with the traditional in-situ synthesis method, the method provided by the present invention does not rely on the use of organic templates, saves costs, is safe and simple to operate, is pollution-free, has high repeatability, and is highly scalable. It can solve the problem of large-scale production and application of molecular sieves in industry, and realizes economic, green, and environmentally friendly industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below.

[0022] Figure 1 Schematic diagram of the principle of the crystal transformation synthesis method;

[0023] Figure 2 This is a SEM image of the ANA type molecular sieve of Example 1;

[0024] Figure 3 This is the modeling image of the kite-shaped icosahedron;

[0025] Figure 4 This is a SEM image of the ANA type molecular sieve of Example 2;

[0026] Figure 5 It is the XRD diagram of ANA type molecular sieve of Examples 1 to 7. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing ANA type molecular sieve by crystal transformation synthesis, comprising the following steps:

[0028] The inorganic base solution is mixed with the Y-type molecular sieve for crystallization; the crystallized product is dried and ground in sequence to obtain the ANA-type molecular sieve.

[0029] In the present invention, the method for preparing the inorganic base solution preferably comprises the following steps: mixing the inorganic base with the solvent to ensure that the inorganic base is completely dissolved to obtain the inorganic base solution.

[0030] In the present invention, the inorganic base in the inorganic base solution preferably includes sodium hydroxide.

[0031] In the present invention, the solvent in the inorganic alkaline solution is preferably water.

[0032] In the present invention, the molar ratio of the inorganic base in the inorganic base solution to the solvent in the inorganic base solution is preferably 0.6-1.4:30-150, more preferably 0.8-1:70-150, and even more preferably 1:100.

[0033] In the present invention, the mixing rate of the inorganic base and the solvent is preferably 800-1200 rpm, more preferably 900-1100 rpm, and more preferably 1000 rpm; the mixing time of the inorganic base and the solvent is preferably ≥10 min, more preferably ≥12 min, and more preferably ≥14 min.

[0034] In the present invention, the Y-type molecular sieve preferably includes one or more of USY-type molecular sieve, HY-type molecular sieve, and NaY-type molecular sieve, and further preferably includes USY-type molecular sieve, HY-type molecular sieve or NaY-type molecular sieve, and more preferably is USY-type molecular sieve.

[0035] In the present invention, the source of the Y-type molecular sieve is not limited, and it can be obtained by using commercial products, non-commercial products or preparation methods well known in the art.

[0036] In the present invention, the molar ratio of the mass of the Y-type molecular sieve to the inorganic base in the inorganic base solution is preferably 60-100 g: 0.8-1 mol, more preferably 70-90 g: 0.9-1 mol, and more preferably 72-78 g: 1 mol.

[0037] In the present invention, the mixing time of the inorganic base solution and the Y-type molecular sieve is preferably 3 to 5.5 hours, more preferably 4 to 5.5 hours, and more preferably 4 hours; the mixing rate of the inorganic base solution and the Y-type molecular sieve is preferably 800 to 1200 rpm, more preferably 900 to 1100 rpm, and more preferably 1000 rpm.

[0038] In the present invention, the crystallization temperature is preferably 160-260° C., more preferably 180-240° C., and more preferably 220° C.; the crystallization time is preferably 6-96 h, more preferably 24-60 h, and more preferably 48 h.

[0039] In the present invention, the crystallized product is preferably subjected to vacuum filtration and washing in sequence before drying.

[0040] In the present invention, the vacuum degree of the vacuum filtration is preferably 0.06 to 0.12 MPa, more preferably 0.08 to 0.095 MPa, and more preferably 0.09 MPa.

[0041] In the present invention, the washing agent is preferably water.

[0042] In the present invention, the washing method is preferably to use water to wash until neutral.

[0043] In the present invention, the drying temperature is preferably 70 to 95° C., more preferably 75 to 85° C., and more preferably 80° C.; the drying time is preferably 10 to 18 h, more preferably 10 to 15 h, and more preferably 12 h.

[0044] In the present invention, the grinding equipment is preferably an agate mortar.

[0045] In the present invention, the grinding preferably further comprises: screening through a 200-mesh screen.

[0046] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In Examples 1 to 11, the HY molecular sieve, NaY molecular sieve and USY molecular sieve are industrial molecular sieve raw powders, all manufactured by Tianjin Nanhua Catalyst Co., Ltd., and belong to the NKF-7 / NKF-7-2 (Y) series of zeolite molecular sieves.

[0048] Example 1

[0049] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0050] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0051] USY molecular sieves were added to an inorganic alkali solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 48 hours;

[0052] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 96.28% and a purity of 99.84%.

[0053] The ANA molecular sieve prepared in Example 1 was observed by scanning electron microscopy. Figure 2 As shown. Figure 2 It can be seen that the microscopic morphology of the sample crystal particles is a kite-shaped icosahedron that is approximately spherical, and the surface is clean and flat, indicating that the sample has good crystallinity. Figure 3 This is the modeling image of the kite-shaped icosahedron (tricropahedron).

[0054] Example 2

[0055] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0056] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0057] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being fully stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 72 hours;

[0058] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 95.68% and a purity of 99.76%.

[0059] The ANA molecular sieve prepared in Example 2 was observed by scanning electron microscopy. Figure 4 As shown. Figure 4 It can be seen that the microscopic morphology of the sample crystal particles is a kite-shaped icosahedron with a clean and flat surface, indicating that the sample has good crystallinity.

[0060] Example 3

[0061] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0062] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0063] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 6 hours;

[0064] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 96.14% and a purity of 99.87%.

[0065] Example 4

[0066] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0067] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0068] USY molecular sieves were added to an inorganic alkali solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the mixture was stirred at 1000 rpm for 4 hours. The obtained gel was transferred to a reactor and crystallized in an oven at 220°C for 12 hours before being taken out.

[0069] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 95.87% and a purity of 99.56%.

[0070] Example 5

[0071] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0072] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0073] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 24 hours;

[0074] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 96.44% and a purity of 98.64%.

[0075] Example 6

[0076] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0077] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0078] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 36 hours;

[0079] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 97.37% and a purity of 99.84%.

[0080] Example 7

[0081] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0082] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0083] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the obtained gel was transferred to a reactor after being fully stirred at a rate of 1000 rpm for 4 hours, and then taken out after crystallization in an oven at 220°C for 60 hours;

[0084] The obtained product was vacuum filtered under 0.09 MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 95.81% and a purity of 99.06%.

[0085] according to Figure 5 From the XRD test results of Examples 1 to 7, it can be seen that the optimal crystal transformation time of ANA type molecular sieve is 24 to 60 hours.

[0086] Example 8

[0087] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0088] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0089] HY molecular sieve was added into the inorganic alkali solution, the molar ratio of HY molecular sieve to sodium hydroxide was 75.30 g:1 mol, and after being fully stirred at a rate of 1000 rpm for 4 hours, the obtained gel was transferred into a reaction kettle, and crystallized in an oven at 220°C for 48 hours before being taken out;

[0090] The obtained product was vacuum filtered under 0.085MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 96.43% and a purity of 99.33%.

[0091] Example 9

[0092] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0093] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:100, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0094] NaY molecular sieves were added to an inorganic alkaline solution, the molar ratio of the mass of the NaY molecular sieves to the mole of sodium hydroxide was 75.30 g:1 mol, and the mixture was stirred at 1000 rpm for 4 hours. The obtained gel was transferred to a reactor, and crystallized in an oven at 220°C for 48 hours before being taken out.

[0095] The obtained product was vacuum filtered under 0.085MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 95.97% and a purity of 99.42%.

[0096] Example 10

[0097] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0098] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 1:150, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0099] USY molecular sieves were added to an inorganic alkaline solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:1 mol, and the mixture was stirred at 800 rpm for 3 h. The obtained gel was transferred to a reactor and crystallized in an oven at 220°C for 48 h before being taken out.

[0100] The obtained product was vacuum filtered under 0.095MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12 hours, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 96.82% and a purity of 99.77%.

[0101] Embodiment 11

[0102] This embodiment provides a method for preparing ANA type molecular sieve by crystallization synthesis, comprising the following steps:

[0103] Sodium hydroxide was dissolved in water, the molar ratio of sodium hydroxide to water was 0.8:70, and the mixture was stirred at a rate of 1000 rpm for 10 min to ensure that the sodium hydroxide was completely dissolved, thereby obtaining an inorganic alkaline solution;

[0104] USY molecular sieves were added to an inorganic alkali solution, the molar ratio of USY molecular sieves to sodium hydroxide was 75.30 g:0.8 mol, and the mixture was stirred at 1200 rpm for 5.5 h. The obtained gel was transferred to a reactor and crystallized in an oven at 220°C for 48 h before being taken out.

[0105] The obtained product was vacuum filtered under 0.08MPa, and then washed with deionized water until neutral. After washing, it was dried in an oven at 80°C for 12h, taken out and ground in an agate mortar, and passed through a 200-mesh sieve to obtain ANA type molecular sieve with a yield of 97.16% and a purity of 98.53%.

[0106] In summary, the present invention provides a method for preparing ANA type molecular sieve by crystallization. In this process, the present invention uses Na + The key guiding role provided by ions realizes the template-free synthesis of ANA type molecular sieves, and gets rid of the dependence of ANA type molecular sieve synthesis on organic templates. In addition, the present invention adopts the Y-type molecular sieve that can be produced on a large scale industrially as a silicon-aluminum source, which not only reduces the cost, but also improves the production efficiency, reduces environmental pollution, and provides favorable conditions for the large-scale production of ANA type molecular sieves. The prepared ANA type molecular sieve has high purity, good crystallinity and price advantages, which fully meets the market demand. At the same time, the present invention also provides an optional recovery route of industrial waste molecular sieves, which can effectively promote the large-scale production and application of molecular sieves in industry. From the results of the embodiment, the method provided by the present invention can realize the complete crystallization of the original molecular sieve, and is converted into an ANA type molecular sieve with excellent morphology and high crystallinity.

[0107] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing ANA type molecular sieve by crystallization synthesis, characterized in that: The following steps are involved: The inorganic base solution is mixed with the Y-type molecular sieve for crystallization; the crystallized product is dried and ground in sequence to obtain the ANA-type molecular sieve.

2. The preparation method according to claim 1, characterized in that: The inorganic alkali in the inorganic alkali solution includes sodium hydroxide, and the solvent in the inorganic alkali solution is water.

3. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of the inorganic base in the inorganic base solution to the solvent in the inorganic base solution is 0.6-1.4:30-150.

4. The preparation method according to claim 1, characterized in that: The Y-type molecular sieve includes one or more of USY-type molecular sieve, HY-type molecular sieve and NaY-type molecular sieve.

5. The preparation method according to claim 3, characterized in that: The molar ratio of the mass of the Y-type molecular sieve to the inorganic base in the inorganic base solution is 60-100 g: 0.8-1 mol.

6. The preparation method according to claim 1 or 4, characterized in that: The time for mixing the inorganic alkali solution and the Y-type molecular sieve is 3 to 5.5 hours, and the speed for mixing the inorganic alkali solution and the Y-type molecular sieve is 800 to 1200 rpm.

7. The preparation method according to claim 6, characterized in that: The crystallization temperature is 160-260° C., and the crystallization time is 6-96 hours.

8. The preparation method according to claim 1, characterized in that: The drying temperature is 70-95° C., and the drying time is 10-18 hours.

9. The preparation method according to claim 1, characterized in that: The grinding further comprises: screening through a 200-mesh screen.

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