Preparation method of high-silicon y-type molecular sieve

Abstract

The present application relates to a kind of preparation methods of high-silicon Y type molecular sieve, comprising the following steps: preparation of directing agent, with ultrastable Y molecular sieve as seed gel preparation silicon source;Metal silicon powder is mixed with hot lye and is reacted to prepare high-activity silicon source, immediately sodium metaaluminate solution, lye, directing agent solution and seed gel are added to high-activity silicon source, after being mixed uniformly, direct current is introduced to carry out processing, after aging, it is transferred to crystallization kettle and is crystallized to obtain high-silicon Y type molecular sieve.The method described in the present application significantly improves the utilization rate of synthesis system silicon source, can directly synthesize high-silicon Y type molecular sieve under the condition of lower feed silicon-aluminum ratio, greatly shortens crystallization time, and is conducive to industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of molecular sieve synthesis, and relates to a preparation method of high-silicon Y-type molecular sieve. BACKGROUND

[0002] Y-type molecular sieve has a FAU framework topology and has a supercage structure arranged by beta cages, and has a pore size of about 0.74 nm. When the framework silicon-aluminum ratio (all below are SiO2 / Al2O3 molar ratio) of NaY molecular sieve > 6, it is called high-silicon Y-type molecular sieve, which often has stronger hydrothermal stability, catalytic activity and adsorption performance, and therefore, the high-silicon Y-type molecular sieve has more extensive applications in the fields of catalysis, adsorption purification and separation.

[0003] The preparation of high-silicon Y-type molecular sieve mainly includes a direct synthesis method and a secondary synthesis method. The secondary synthesis method needs to perform dealumination and silicon supplementation on the conventional NaY molecular sieve through multiple high-temperature hydrothermal reactions or high-temperature gas phase reactions, which can easily cause a serious decrease in the crystallinity of the molecular sieve, in addition, the process is complicated, has high energy consumption and causes serious pollution. Compared with the secondary synthesis method, the direct synthesis method has simple steps, high efficiency and small pollution, and therefore, becomes a research hotspot for the preparation of high-silicon Y-type molecular sieve.

[0004] Currently, the direct synthesis method mainly includes template method and template-free method. The template method needs to add expensive crown ethers, imidazoles or organic ammonium substances as templates in the preparation system, which significantly increases the production cost and causes serious pollution, and is not conducive to large-scale industrial production. The template-free method has simple process, low production cost, small environmental pollution and better industrial application prospect. In 1972, the US Grace Company first proposed in US3639099 to use water glass as the silicon source and add a crystallization directing agent in the synthesis system to prepare Y molecular sieve, but the prepared Y molecular sieve has a framework silicon-aluminum ratio of less than 5.2. Since then, researchers have improved the method for preparing high-silicon Y molecular sieve by template-free method on this basis. CN108569705B adds organosiloxane as a promoter in the directing agent and reaction gel, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio of 5.5-6.5 after aging for 12-192 hours and crystallization for 18-72 hours at a feeding silicon-aluminum ratio of 7-10. CN110078084B uses solid silicic acid, microspherical silica gel or white carbon black and polymer treated at high temperature to obtain a high-activity silicon source as raw material, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio of 5.5-7.0 by adding a directing agent, aging for 24-180 hours and crystallizing for 2-24 hours at a feeding silicon-aluminum ratio of 7.5-10.5. CN101468804B introduces an ester or alcohol additive in the system with the added directing agent, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio of 5.5-6.0 after crystallization for 10-55 hours at a feeding silicon-aluminum ratio of 6-10. CN101767799B uses water glass as the silicon source, and synthesizes high-silicon Y molecular sieve with a silicon-aluminum ratio higher than 6.0 and a crystal grain size of 50-150 nm by adding a directing agent aged at 0-10℃ for 50-120 hours at a feeding silicon-aluminum ratio of 6-10. CN1033503C prepares an improved directing agent with a light transmittance of >75% by supplementing a silicon source in a conventional directing agent, and obtains Y molecular sieve with a silicon-aluminum ratio of 5.8 at a feeding silicon-aluminum ratio higher than 12 by using conventional hydrothermal method. CN102198950B uses water glass as the silicon source, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio of 5.6-6.2 by separately crystallizing different proportioned gels for more than 16 hours and then mixing and re-crystallizing for more than 24 hours. CN103896303B uses water glass as the silicon source, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio higher than 6.5 and an average particle size of 100-500 nm by adding a directing agent and performing three-stage dynamic crystallization at a feeding silicon-aluminum ratio of 10-25. CN101251929B uses water glass as the raw material, and prepares high-silicon Y molecular sieve with a silicon-aluminum ratio of 5.5-6.0 by adding low-alkalinity silicon-aluminum gel to high-alkalinity silicon-aluminum gel after crystallization for a period of time.

[0005] In summary, the current direct preparation of high-silicon Y molecular sieve technology can improve the product silicon aluminum ratio, but there are still high feed silicon aluminum ratio, low silicon source utilization rate, limited improvement of framework silicon aluminum ratio, long crystallization time, complex process flow, and the need for additional organic substances, etc. Therefore, it is urgent to study a simple and efficient high-silicon Y molecular sieve preparation process. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of high-silicon Y molecular sieve, which can significantly improve the silicon source utilization rate of the synthesis system, can directly synthesize high-silicon Y molecular sieve under the condition of lower feed silicon aluminum ratio, and greatly shorten the crystallization time.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] A preparation method of high-silicon Y molecular sieve, characterized in that it comprises the following steps:

[0009] S1, mixing sodium aluminate solution, sodium hydroxide and deionized water, then adding ultrastable Y molecular sieve (ultrastable Y for short) in the mixed solution, stirring uniformly, once crystallization, and preparing seed gel;

[0010] S2, placing water glass, sodium aluminate solution and water according to the molar ratio of SiO2:Al2O3:Na2O:H2O = 15-20:1:15-20:280-360, and aging to obtain a directing agent solution;

[0011] S3, mixing silicon powder, alkali source and deionized water under heating and stirring for one-time reaction, then adding aluminate, sodium aluminate solution and deionized water for mixing to obtain a reaction gel, then continuously adding the seed gel in S1 and the directing agent solution in S2, mixing uniformly, and then passing direct current for aging treatment;

[0012] S4, aging the aged material, then transferring to a crystallization kettle for secondary crystallization to obtain high-silicon Y molecular sieve.

[0013] Further, in S1, the addition amount of sodium aluminate solution, sodium hydroxide and deionized water satisfies: Al2O3:Na2O:H2O = 1:8-25:100-350, it should be pointed out here that Al2O3:Na2O:H2O is only a measurement form adopted for the convenience of calculating the ratio of different components, and does not mean that the components in the solution exist in the form of "Al2O3, Na2O", etc., which is the common knowledge in the art.

[0014] The weight ratio of the mixed solution to the ultrastable Y molecular sieve is 2-10:1.

[0015] Further, in S1, the temperature of the primary crystallization is 70-120℃, and the crystallization time is 2-8 hours.

[0016] Further, in S1, the ultra-stable Y molecular sieve, i.e. the Y-type molecular sieve with high silicon-to-aluminum ratio, has a framework silicon-to-aluminum ratio higher than 20. Specifically, a conventional commercially available product meeting the above-mentioned condition can be used, and since the specific source is not the innovation of the present application, no further description is given herein.

[0017] Further, in S2, the temperature of the standing and aging is room temperature to 60℃, and the time is 12-48 hours.

[0018] Further, in S3, the molar ratio of the silicon powder, the alkali source and the deionized water is 1:0.6-0.8:7-13.

[0019] The temperature of the primary reaction is 50-70℃, and the time is 3-8 hours. Preferably, the alkali source is one or more of NaOH, KOH or ammonia water, and more preferably, the alkali source is NaOH.

[0020] Further, the metal silicon powder has a size of 150-500 mesh, and the silicon content is higher than 97.0%.

[0021] Further, in S3, the addition amounts of the aluminate, the sodium aluminate solution and the deionized water satisfy the following condition: SiO2:Al2O3:M x O:H2O=5-12:1:0.5-4:80-300, the addition amount of the seed gel is 1-15wt% of the reaction gel, and the addition amount of the directing agent solution is 1-15wt% of the reaction gel. Preferably, the aluminate is one or more of aluminum sulfate, aluminum chloride or aluminum nitrate, and further preferably, the aluminate is aluminum sulfate. Specifically, M includes Na and other alkali metal cations possibly contained in the alkali source, for example, when the alkali source is sodium hydroxide, M is Na; and when the alkali source is KOH, M includes Na and K.

[0022] Further, in S3, during the aging treatment, the current density of the direct current is 50-100mA / cm 2 , and the treatment time is 0.5-3h.

[0023] Further, in S4, the temperature of the aging treatment is room temperature-60℃, and the aging time is 2-12h.

[0024] Further, in S4, the temperature of the secondary crystallization is 80-120℃, and the crystallization time is 6-30h.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1. In the synthesis process, the present invention utilizes the reaction of metallic silicon powder and alkaline solution to prepare a highly active silicon source. The silicate anions have a low degree of polymerization and are concentrated, making them more likely to dissolve, polymerize and rearrange in a low-alkalinity reaction system, thus accelerating the formation of crystal nuclei and improving the utilization rate of the silicon source.

[0027] 2. This invention uses a seed gel that introduces incomplete crystallization into the crystallization system, with ultrastable Y as the silicon source. Due to its high framework silicon content, after a short period of incomplete crystallization, the gel contains a large number of uncrystallized high-silicon crystal nuclei and scattered high-silicon secondary structural unit fragments, which play a certain guiding role in the synthesis of high-silicon Y-type molecular sieves. It can accelerate the crystallization process while increasing the silicon-to-aluminum ratio of the Y molecular sieve framework.

[0028] 3. In this invention, direct current is introduced into the crystallization system. The hydroxyl radicals generated by electrolysis can promote the depolymerization and reconstruction of polysilicate. Furthermore, due to the presence of hydroxyl radicals during the nucleation stage, the self-assembly polymerization and rearrangement process of Si-O-Si bonds around the crystal nucleus or secondary structural units can be accelerated, thereby increasing the skeletal silicon-aluminum ratio of Y molecular sieve.

[0029] 4. The present invention has simple steps, can reduce the alkalinity of the system, and improve the utilization rate of silicon source, so as to realize the rapid preparation of high silicon Y-type molecular sieve under the condition of low silicon-aluminum ratio. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0031] In the following embodiments, the cell constant of NaY molecular sieve was determined by X-ray diffraction. First, the cell constant a of Y zeolite was determined according to the standard method of SH / T0339-92. Then, the silicon-to-aluminum ratio of NaY molecular sieve was calculated according to the Breck-Flanigen formula: SiO2 / Al2O3=2(25.858-a) / (a-24.191).

[0032] Furthermore, the ultra-stable Y used in this embodiment was purchased from Fuyu (Zhangjiagang) New Materials Co., Ltd., and its models corresponding to different silicon-to-aluminum ratios in Examples 1 to 3 are SAR-30, SAR-60, and SAR-20, respectively. Of course, in the following embodiments, other commercially available products can also be used, and under the condition of meeting the same silicon-to-aluminum ratio, there is basically no impact on the performance of the final product.

[0033] Unless otherwise specified, all other raw materials or processing techniques are commercially available materials or conventional processing techniques in the field.

[0034] Example 1:

[0035] Seed gel preparation: 10.0 g NaOH was dissolved in 26.2 g deionized water according to the molar ratio of Al2O3:Na2O:H2O = 1:15:200, after stirring uniformly, 12.4 g sodium aluminate solution (the concentration of Na2O is 12.43%, the concentration of Al2O3 is 8.25%, the same below) was added, stirred uniformly, then 8.1 g of ultra-stable Y with a framework silica-alumina ratio of 30 was added according to the ratio of mixed solution:ultra-stable Y = 6:1, after stirring uniformly for 2 h, it was crystallized at 90 ℃ for 3 h to obtain the seed gel.

[0036] Directing agent solution preparation: 7.2 g NaOH was dissolved in 24.0 g deionized water, then 12.4 g of sodium aluminate solution was added, finally 35.7 g of conventional 3.2 M water glass (SiO2 content is 25.2%, Na2O content is 8.1%) was added, after stirring uniformly, it was aged at 30 ℃ for 24 h to obtain the directing agent solution, wherein the molar ratio of the composition is SiO2:Al2O3:Na2O:H2O = 15:1:16:320.

[0037] According to the molar ratio of metal silicon powder, NaOH and deionized water 1:0.6:10.5, 4.9 g NaOH was dissolved in 38.3 g deionized water, after stirring uniformly at 60 ℃, 5.7 g of 200 mesh metal silicon powder was added, and refluxed for 4 h, after the reaction was completed, 5.7 g of aluminum sulfate octadecahydrate, 20.4 g of sodium aluminate solution and 31.5 g of deionized water were added, and stirred uniformly, the molar ratio of the composition was SiO2:Al2O3:Na2O:H2O = 8:1:2.0:180, 10.0 g of seed gel and 10.0 g of directing agent solution were added according to 8% of the weight of the reaction gel respectively, and stirred uniformly, then direct current with a current density of 80 mA / cm2was passed in, and treated for 1 h. Finally, the treated reaction gel was aged at 50 ℃ for 6 h and then transferred to a crystallization kettle for crystallization at 100 ℃ for 24 h, after the reaction was completed, it was filtered, washed and dried to obtain Y type molecular sieve. The silica-alumina ratio measured by XRD was 6.5, and the relative crystallinity was 97%. 2

[0038] Example 2

[0039] The directing agent solution was prepared as in Example 1.

[0040] ​Seed gel preparation: 14.2 g NaOH was dissolved in 17.2 g deionized water according to the molar ratio of Al2O3:Na2O:H2O = 1:20:150, and after stirring uniformly, 12.4 g sodium metaaluminate solution was added, and stirred uniformly, then 10.9 g of the Y zeolite with a framework silica-alumina ratio of 60 was added according to the ratio of mixed solution: Y = 4:1, and after stirring uniformly for 2 h, crystallization was carried out at 110 °C for 3 h to obtain the seed gel.

[0041] According to the molar ratio of metal silicon powder, KOH and deionized water 1:0.8:13, 6.7 g KOH was dissolved in 35.2 g deionized water, and after stirring uniformly at 70 °C, 4.2 g of 200 mesh metal silicon powder was added, and refluxed for 6 h, then 13.3 g of aluminum sulfate octadecahydrate, 6.2 g of sodium metaaluminate solution and 4.1 g of deionized water were added, and stirred until uniform, the composition molar ratio was SiO2:Al2O3:(Na2O+K2O):H2O = 6:1:1.0:90, 7.0 g of seed gel was added according to 10% of the weight of the reaction gel, 2.1 g of directing agent solution was added according to 3.0% of the weight of the reaction gel, and stirred until uniform, then direct current with a current density of 90 mA / cm 2 was introduced, and treated for 0.5 h. Finally, the treated reaction gel was transferred to a crystallization kettle and crystallized at 100 °C for 24 h after aging at 50 °C for 8 h, and after filtration, washing and drying, Y type molecular sieve was obtained. The silica-alumina ratio was 5.6, and the relative crystallinity was 93% as measured by XRD.

[0042] Example 3

[0043] The directing agent solution was prepared as in Example 1.

[0044] Seed gel preparation: 14.2 g NaOH was dissolved in 17.2 g deionized water according to the molar ratio of Al2O3:Na2O:H2O = 1:20:150, and after stirring uniformly, 12.4 g sodium metaaluminate solution was added, and stirred uniformly, then 10.9 g of the Y zeolite with a framework silica-alumina ratio of 60 was added according to the ratio of mixed solution: Y = 4:1, and after stirring uniformly for 2 h, crystallization was carried out at 110 °C for 3 h to obtain the seed gel.

[0045] According to the molar ratio of metal silicon powder, alkali source and deionized water 1:0.6:7, 4.0 g NaOH was weighed into 29.1 g deionized water, 3.4 g ammonia water with a concentration of 25% was added and stirred uniformly at 50°C, then 7.0 g of 500 mesh metal silicon powder was added, and refluxed for 8 h. After the reaction was completed, 3.0 g of aluminum sulfate octadecahydrate, 25.4 g of sodium metaaluminate solution and 65.6 g of deionized water were added and stirred uniformly. The molar ratio of the composition was SiO2:Al2O3:Na2O:H2O=10:1:3.0:250. According to 3.0% of the weight of the reaction gel, 4.1 g of seed gel was added. According to 10.0% of the weight of the reaction gel, 13.8 g of directing agent solution was added and stirred uniformly. Then direct current with a current density of 60 mA / cm2was passed for 2 h. Finally, the treated reaction gel was transferred to a crystallization kettle and crystallized at 100°C for 12 h after aging at 40°C for 8 h. After the reaction was completed, the product was filtered, washed and dried to obtain Y molecular sieve. The silicon-aluminum ratio was 7.1 and the relative crystallinity was 94% as measured by XRD. 2

[0046] Example 4

[0047] The directing agent solution and the seed gel were prepared as in Example 1.

[0048] According to the molar ratio of metal silicon powder, alkali source and deionized water 1:0.6:7, 4.0 g NaOH was weighed into 29.1 g deionized water, 3.4 g ammonia water with a concentration of 25% was added and stirred uniformly at 50°C, then 7.0 g of 500 mesh metal silicon powder was added, and refluxed for 8 h. After the reaction was completed, 3.0 g of aluminum sulfate octadecahydrate, 25.4 g of sodium metaaluminate solution and 65.6 g of deionized water were added and stirred uniformly. The molar ratio of the composition was SiO2:Al2O3:Na2O:H2O=10:1:3.0:250. According to 3.0% of the weight of the reaction gel, 4.1 g of seed gel was added. According to 10.0% of the weight of the reaction gel, 13.8 g of directing agent solution was added and stirred uniformly. Then direct current with a current density of 60 mA / cm2was passed for 2 h. Finally, the treated reaction gel was transferred to a crystallization kettle and crystallized at 100°C for 12 h after aging at 40°C for 8 h. After the reaction was completed, the product was filtered, washed and dried to obtain Y molecular sieve. The silicon-aluminum ratio was 7.1 and the relative crystallinity was 94% as measured by XRD. 2

[0049] Comparative Example 1

[0050] The directing agent was prepared as in Example 1.

[0051] The reaction gel was prepared as in Example 1, but no seed gel was added to the reaction gel.

[0052] Specifically as follows:​​

[0053] According to the molar ratio of metal silicon powder, NaOH and deionized water being 1:0.6:10.5, 4.9g NaOH was dissolved in 38.3g deionized water, stirred uniformly at 60°C, then 5.7g 200 mesh metal silicon powder was added, refluxed for 4h, after the reaction was completed, 5.7g aluminum sulfate octadecahydrate, 20.4g sodium aluminate solution and 31.5g deionized water were added, stirred until uniform, the molar ratio of the composition was SiO2:Al2O3:Na2O:H2O=8:1:2.0:180, 10.0g directing agent solution was added according to 8% of the weight of the reaction gel, stirred until uniform, then direct current with current density of 80mA / cm2was passed in, treated for 1h. Finally, the treated reaction gel was transferred to a crystallization kettle after aging at 50°C for 6h and crystallized at 100°C for 24h, after the reaction was completed, it was filtered, washed and dried to obtain Y molecular sieve. The silicon to aluminum ratio measured by XRD was 5.9, and the relative crystallinity was 95%. 2

[0054] Comparative Example 2

[0055] The preparation method of the directing agent was the same as that of Example 1.

[0056] The preparation method of the reaction gel was the same as that of Example 1, but direct current was not introduced during the preparation process. Specifically as follows:

[0057] According to the molar ratio of metal silicon powder, NaOH and deionized water being 1:0.6:10.5, 4.9g NaOH was dissolved in 38.3g deionized water, stirred uniformly at 60°C, then 5.7g 200 mesh metal silicon powder was added, refluxed for 4h, after the reaction was completed, 5.7g aluminum sulfate octadecahydrate, 20.4g sodium aluminate solution and 31.5g deionized water were added, stirred until uniform, the molar ratio of the composition was SiO2:Al2O3:Na2O:H2O=8:1:2.0:180, 10.0g directing agent solution was added according to 8% of the weight of the reaction gel, stirred until uniform, then direct current with current density of 80mA / cm2was passed in, treated for 1h. Finally, the treated reaction gel was transferred to a crystallization kettle after aging at 50°C for 6h and crystallized at 100°C for 24h, after the reaction was completed, it was filtered, washed and dried to obtain Y molecular sieve. The silicon to aluminum ratio measured by XRD was 5.9, and the relative crystallinity was 95%.

[0058] Comparative Example 3

[0059] The preparation method of the directing agent and the seed gel was the same as that of Example 1

[0060] ​The reaction gel was prepared according to the method of Example 1. However, the silicon source used in the preparation process was conventional 3.2M water glass having a SiO2content of 25.2% and a Na2O content of 8.1%. The preparation was as follows:

[0061] A 47.6g sample of conventional 3.2M water glass was weighed out and 4.0g of aluminium sulfate octadecahydrate, 23.5g of sodium metaaluminate solution and 30.6g of deionized water were added thereto with stirring to homogeneity. The molar ratio of the composition was SiO2:Al2O3:Na2O:H2O = 8:1:2.0:180. 8.5g of seed gel was added at 8% by weight of the reaction gel, and 8.5g of directing agent solution was added at 8% by weight of the reaction gel with stirring to homogeneity. Then direct current was passed at a current density of 80mA / cm2for 1h. Finally, the treated reaction gel was aged at 50°C for 6h and then transferred to a crystallization kettle for crystallization at 100°C for 24h. After the reaction was completed, the product was filtered, washed and dried to obtain Y molecular sieve. XRD analysis showed that the silica-alumina ratio was 5.7 and the relative crystallinity was 92%. 2

[0062] Comparative Example 4

[0063] The directing agent was prepared according to the method of Example 1 and the reaction gel had the same composition ratio as in Example 1.

[0064] Y molecular sieve was prepared according to the conventional directing agent method using conventional 3.2M water glass as the silicon source (SiO2content of 25.2% and Na2O content of 8.1%). The preparation was as follows:

[0065] A 47.6g sample of conventional 3.2M water glass was weighed out and 4.0g of aluminium sulfate octadecahydrate, 23.5g of sodium metaaluminate solution and 30.6g of deionized water were added thereto with stirring to homogeneity. The molar ratio of the composition was SiO2:Al2O3:Na2O:H2O = 8:1:2.0:180. 8.5g of directing agent solution was added at 8% by weight of the reaction gel with stirring to homogeneity. The reaction gel was aged at 50°C for 6h and then transferred to a crystallization kettle for crystallization at 100°C for 24h. After the reaction was completed, the product was filtered, washed and dried to obtain Y molecular sieve. XRD analysis showed that the silica-alumina ratio was 5.2 and the relative crystallinity was 95%.

[0066] The foregoing description of the working examples is to enable one of ordinary skill in the art to understand and use the invention. Various modifications to these examples can be readily made and will be apparent to those skilled in the art, and thus, the scope of the invention is not to be limited to the examples described herein. Rather, it is intended to cover all modifications and variations within the scope of the invention.​

Claims

1. A process for preparing a high-silica Y-type molecular sieve, characterized by, The method comprises the following steps: S1, mixing sodium metaaluminate solution, sodium hydroxide and deionized water, then adding ultrastable Y molecular sieve in the mixed solution, stirring uniformly, once crystallization, and preparing seed gel; S2, according to the molar ratio of SiO2:Al2O3:Na2O:H2O=15-20:1:15-20:280-360, aging and curing the water glass, sodium metaaluminate solution and water to obtain a directing agent solution; S3, mixing silicon powder, alkali source and deionized water under heating and stirring for once reaction, then adding aluminate, sodium metaaluminate solution and deionized water for mixing to obtain a reaction gel, then continuously adding the seed gel in S1 and the directing agent solution in S2, mixing uniformly, and then passing direct current for aging treatment; S4, aging the material after aging, then transferring to a crystallization kettle for secondary crystallization to obtain high-silicon Y type molecular sieve.

2. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S1, the addition amount of sodium metaaluminate solution, sodium hydroxide and deionized water satisfies the molar ratio of Al2O3:Na2O:H2O=1:8-25:100-350, The weight ratio of the mixed solution to the ultrastable Y molecular sieve is 2-10:

1.

3. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S1, the temperature of once crystallization is 70-120℃, and the crystallization time is 2-8 hours.

4. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S1, the skeleton silicon aluminum ratio of the ultrastable Y molecular sieve is higher than 20.

5. The method of making a high-silica Y-type molecular sieve of claim 1, wherein, In S2, the temperature of static aging is room temperature to 60℃, and the time is 12-48h.

6. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S3, the molar ratio of silicon powder, alkali source and deionized water is 1:0.6-0.8:7-13; The temperature of once reaction is 50-70℃, and the time is 3-8 hours; The alkali source is one or more of NaOH, KOH or ammonia.

7. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S3, the added amounts of aluminate, sodium metaaluminate solution and deionized water satisfy the molar ratio: SiO2:Al2O3:M=1:0.5-2:0.5-2 x O:H2O=5-12:1:0.5-4:80-300, the added amount of the seed gel accounts for 1-15wt% of the mass of the reaction gel, the added amount of the directing agent solution accounts for 1-15wt% of the mass of the reaction gel, M includes Na and the alkaline metal cations contained in the alkali source; The aluminate is one or more of aluminum sulfate, aluminum chloride or aluminum nitrate.

8. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S3, the current density of the direct current is 50-100 mA / cm2 during the aging treatment process, and the treatment time is 0.5-3 h. 2 , the treatment time is 0.5-3 h.

9. The method for preparing a high-silica Y-type molecular sieve according to claim 1, characterized in that, In S4, the temperature of aging treatment is room temperature to 60℃, and the aging time is 2-12h.

10. The method of making a high-silica Y-type molecular sieve of claim 1, wherein, In S4, the temperature of secondary crystallization is 80-120℃, and the crystallization time is 6-30h.