阅读说明：本技术 一种高结晶度sapo-20沸石分子筛的制备方法 (Preparation method of SAPO-20 zeolite molecular sieve with high crystallinity ) 是由 季筱楠 向梅 吴泽颖 邓瑶瑶 于 2021-08-24 设计创作，主要内容包括：本发明涉及一种高结晶度SAPO-20沸石分子筛的制备方法,其特征在于,包括如下步骤：(1)将铝源溶于水中,加入磷源,搅拌均匀,加入水玻璃溶液,继续搅拌均匀,然后加入胺类模板剂,再搅拌24h；所述铝源以Al-(2)O-(3)计,所述磷源以P-(2)O-(5)计,所述水玻璃以SiO-(2)计,各原材料投料摩尔量之比为Al-(2)O-(3):H-(2)O:P-(2)O-(5):SiO-(2):胺类模板剂＝0.8:40:1.0:(0.8-1):(1.1-1.5)；(2)转移至高压反应釜中,于180～220℃下进行晶化反应36-96h后,得到高结晶度SAPO-20沸石分子筛。本发明方法制得的SAPO-20沸石分子筛结晶度可高达99.99％。(The invention relates to a preparation method of a high-crystallinity SAPO-20 zeolite molecular sieve, which is characterized by comprising the following steps: (1) dissolving an aluminum source in water, adding a phosphorus source, uniformly stirring, adding a water glass solution, continuously uniformly stirring, adding an amine template, and stirring for 24 hours; the aluminum source is Al 2 O 3 In terms of P, the phosphorus source is 2 O 5 The water glass is calculated by SiO 2 The molar weight ratio of the raw materials is Al 2 O 3 :H 2 O:P 2 O 5 :SiO 2 Amine template agent 0.8:40:1.0, (0.8-1) and (1.1-1.5); (2) and transferring the mixture into a high-pressure reaction kettle, and carrying out crystallization reaction at 180-220 ℃ for 36-96h to obtain the SAPO-20 zeolite molecular sieve with high crystallinity. The crystallinity of the SAPO-20 zeolite molecular sieve prepared by the method can reach as high as 99.99 percent.)

1. A preparation method of a high-crystallinity SAPO-20 zeolite molecular sieve is characterized by comprising the following steps:

(1) dissolving an aluminum source in water, adding a phosphorus source, uniformly stirring, adding a water glass solution, continuously uniformly stirring, adding an amine template, and stirring for 24 hours; the aluminum source is Al₂O₃In terms of P, the phosphorus source is₂O₅The water glass is calculated by SiO₂The molar weight ratio of the raw materials is Al₂O₃:H₂O:P₂O₅:SiO₂Amine template agent 0.8:40:1.0, (0.8-1) and (1.1-1.5);

(2) and transferring the mixture into a high-pressure reaction kettle, performing crystallization reaction at 180-220 ℃ for 36-96h, taking out the product, washing the product to be neutral, performing suction filtration and drying to obtain the high-crystallinity SAPO-20 zeolite molecular sieve.

2. The method for preparing the SAPO-20 zeolite molecular sieve with high crystallinity as claimed in claim 1, wherein the aluminum source is pseudoboehmite and the phosphorus source is phosphoric acid solution with 85 wt% concentration; the amine template agent is N, N, N ', N' -tetramethyl-1, 6-ethylenediamine.

3. The method of claim 1, wherein the SiO in the water glass solution is used as a material for preparing the SAPO-20 zeolite molecular sieve with high crystallinity₂The concentration is 4.9581mol/L, Na₂O concentration is 1.5357mol/L, H₂The O concentration was 51.0692 mol/L.

4. The method of claim 1, wherein the molar ratio of the raw materials is Al₂O₃:H₂O:P₂O₅:SiO₂Amine templating agent 0.8:40:1.0:0.6: 1.2.

5. The method for preparing the SAPO-20 zeolite molecular sieve with high crystallinity according to claim 1, wherein the temperature of the crystallization reaction is 200 to 210 ℃ and the time is 48 to 72 hours.

6. The method for preparing the SAPO-20 zeolite molecular sieve with high crystallinity according to claim 5, wherein the temperature of the crystallization reaction is 210 ℃ and the time is 48 h.

Technical Field

The invention relates to the technical field of synthesis of zeolite molecular sieves, in particular to a preparation method of a high-crystallinity SAPO-20 zeolite molecular sieve.

Background

SAPO-20, AlPO-20 and sodalite are heterogeneous and isomorphous, belong to a cubic system, have a pore size of 0.3nm (six-membered ring), have an acidic surface, and can be well used as a catalyst, a catalyst carrier, an ion exchanger and an adsorbent for separating and purifying molecules, so that the SAPO-20, the AlPO-20 and the sodalite are widely concerned in the fields of industrial catalysis, adsorption separation, ion exchange and the like.

The synthesis of microporous SAPO-20 zeolite molecular sieve mainly includes hydrothermal crystallization, dry gel conversion, liquid phase crystallization and other methods. The dry gel conversion method and the liquid phase crystallization method need to grind the prepared molecular sieve precursor, and the size of the ground dry gel particles greatly affects the crystallinity of the molecular sieve, so that the process is complicated and uncontrollable. SAPO-34 molecular sieve is also used as a raw material to synthesize SAPO-20 by high-temperature crystallization with an alkali fusion method, but the method has large equipment loss due to overhigh alkalinity of a synthesis system and is difficult to operate. In other related researches, the SAPO-20 is synthesized by a hydrothermal crystallization method, but the hydrothermal crystallization method is accompanied by mixed crystals and eutectic phenomena, and the crystallinity is not high.

Therefore, we tried to develop a method for directly synthesizing a high-purity SAPO-20 zeolite molecular sieve. The water glass is used as a silicon source, so that the dependence of a synthesis system on strong alkaline inorganic salt is reduced, the guiding effect of an anion structure is further utilized, the synthesis process is simple, the corrosion to equipment is reduced, and the cost is greatly saved.

Disclosure of Invention

In order to solve the problem that the prior method can not directly synthesize SAPO-20 with high crystallinity, the preparation method of the SAPO-20 zeolite molecular sieve with high crystallinity is provided. The invention synthesizes the pure-phase SAPO-20 molecular sieve by using water glass as a silicon source and fully utilizing the structure-oriented action of anions.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a preparation method of a high-crystallinity SAPO-20 zeolite molecular sieve comprises the following steps:

(1) dissolving an aluminum source in water, adding a phosphorus source, uniformly stirring, adding a water glass solution, continuously uniformly stirring, adding an amine template, and stirring for 24 hours; the aluminum source is Al₂O₃In terms of P, the phosphorus source is₂O₅The water glass is calculated by SiO₂The molar weight ratio of the raw materials is Al₂O₃:H₂O:P₂O₅:SiO₂Amine (A)The template-like agent is 0.8:40:1.0, (0.8-1) and (1.1-1.5);

(2) and transferring the mixture into a high-pressure reaction kettle, performing crystallization reaction at 180-220 ℃ for 36-96h, taking out the product, washing the product to be neutral, performing suction filtration and drying to obtain the high-crystallinity SAPO-20 zeolite molecular sieve.

Further, the aluminum source is pseudo-boehmite, and the phosphorus source is a phosphoric acid solution with the concentration of 85 wt%; the amine template agent is N, N, N ', N' -tetramethyl-1, 6-ethylenediamine (TMHD).

Further, SiO in the water glass solution₂The concentration is 4.9581mol/L, Na₂O concentration is 1.5357mol/L, H₂The O concentration was 51.0692 mol/L.

Preferably, the molar ratio of the raw materials is Al₂O₃:H₂O:P₂O₅:SiO₂Amine templating agent 0.8:40:1.0:0.6: 1.2.

Preferably, the temperature of the crystallization reaction is 200-210 ℃ and the time is 48-72 h.

More preferably, the temperature of the crystallization reaction is 210 ℃ and the time is 48 h. The hydrothermal time of the SAPO-20 molecular sieve synthesis process reported at present is 3-5 days, the crystallization time is increased to be beneficial to improving the crystallinity, and the crystallization time can be greatly reduced to 48 hours in the invention.

The beneficial technical effects are as follows:

the invention utilizes water glass as a silicon source, directly synthesizes SAPO-20 zeolite by a hydrothermal crystallization method, does not need a large amount of template agent and longer hydrothermal crystallization time, greatly improves the synthesis efficiency and reduces the synthesis cost. The synthetic method is simple and has low requirements on equipment, and enterprises producing the zeolite molecular sieve can put into production by utilizing the existing equipment.

Drawings

FIG. 1 is an XRD pattern of the product of examples 1-2, wherein curve a represents example 1 using silica gel and curve b represents example 2 using water glass.

FIG. 2 is an XRD pattern of the products of examples 2-6, wherein curve a represents example 2 with a silicon to phosphorus ratio of 0.6, curve b represents example 3 with a silicon to phosphorus ratio of 0.7, curve c represents example 4 with a silicon to phosphorus ratio of 0.8, curve d represents example 5 with a silicon to phosphorus ratio of 0.9, and curve e represents example 6 with a silicon to phosphorus ratio of 1.0.

FIG. 3 is an XRD pattern of the products of examples 6-10, wherein curve a shows nTMHD: nP₂O₅Example 6 with 1.5, curve b indicates nTMHD nP₂O₅Example 7 with 1.4, curve c indicates nTMHD nP₂O₅Example 8 with 1.3, curve d indicates nTMHD nP₂O₅Example 9 with 1.2, curve e indicates nTMHD nP₂O₅Example 10 of 1.1.

FIG. 4 is an XRD pattern of the products of examples 11-15, wherein curve a shows example 11 with a crystallization temperature of 180 deg.C, curve b shows example 12 with a crystallization temperature of 190 deg.C, curve c shows example 13 with a crystallization temperature of 200 deg.C, curve d shows example 14 with a crystallization temperature of 210 deg.C, and curve e shows example 15 with a crystallization temperature of 220 deg.C.

FIG. 5 is an XRD pattern of the products of examples 14 and 16-21, wherein curve a shows example 16 with crystallization time 24h, curve b shows example 17 with crystallization time 36h, curve c shows example 14 with crystallization time 48h, curve d shows example 18 with crystallization time 60h, curve e shows example 19 with crystallization time 72h, curve f shows example 20 with crystallization time 84h, and curve g shows example 21 with crystallization time 96 h.

Figure 6 is an XRD pattern of the product of example 14, comparative example 1, where curve a represents comparative example 1 and curve b represents example 14.

FIG. 7 is a SEM image of the product of example 14.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless specifically stated otherwise, the numerical values set forth in these examples do not limit the scope of the invention. Techniques, methods known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

The experimental methods of the following examples, which are not specified under specific conditions, are generally determined according to national standards; if no corresponding national standard exists, the method is carried out according to the universal international standard or the standard requirement proposed by related enterprises. Unless otherwise indicated, all parts are parts by weight and all percentages are percentages by weight.

Used as follows H₃PO₄The solution concentration was 85 wt%.

Example 1

Taking 3.25g of pseudo-boehmite and using 21mL of H₂O dilution and 4.2mL of H was added₃PO₄The solution was stirred for 30 min. Silica gel 1.86g was added, followed by stirring with 9.8mL of TMHD for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out the product, washing with water to be neutral, and performing suction filtration and drying to obtain the product.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:0.6:1.5。

Example 2

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 3.7mL of water glass to 5.7mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

want to dissolve4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.8mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:0.6:1.5。

Example 3

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 4.3mL of water glass to 5.6mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.8mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:0.7:1.5。

Example 4

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 4.9mL of water glass to 5.5mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.8mL TMHD was added and stirred for 24 h. Then the mixture is moved into a high-pressure reaction kettle for sealing, after the mixture reacts for 48 hours at the temperature of 220 ℃, the product is taken out, washed by water to be neutral, and pumped outFiltering and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:0.8:1.5。

Example 5

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 5.6mL of water glass to 5.4mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.8mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:0.9:1.5。

Example 6

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 6.2mL of water glass to 5.4mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.8mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:1.0:1.5。

Example 7

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 6.2mL of water glass to 5.4mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 9.2mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:1.0:1.4。

Example 8

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 6.2mL of water glass to 5.4mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 8.5mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:1.0:1.3。

Example 9

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 6.2mL of water glass to 5.4mLH₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 7.9mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:1.0:1.2。

Example 10

Water glass composition, SiO₂:4.9581mol/L，Na₂O:1.5357mol/L，H₂O:51.0692mol/L；

Solution A: dissolve 6.2mL of water glass to 5.4mL of H₂O is in;

solution B: 3.25g of pseudo-boehmite was dissolved in 15mL of H₂O is in;

4.2mL of H was added to solution B₃PO₄The solution was stirred for 30min, then solution A was added dropwise, stirred for another 30min, then 7.2mL TMHD was added and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 220 ℃ for 48 hours, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

Molar ratio of materials in the system Al₂O₃:H₂O:P₂O₅:SiO₂:TMHD＝0.8:40:1.0:1.0:1.1。

Examples 11 to 15

The products of examples 11 to 15 were prepared in the same manner as in example 9 except that the crystallization reaction temperature was different.

The crystallization reaction temperature of example 11 was 180 ℃.

The crystallization reaction temperature of example 12 was 190 ℃.

The crystallization reaction temperature of example 13 was 200 ℃.

The crystallization reaction temperature of example 14 was 210 ℃.

The crystallization reaction temperature of example 15 was 220 ℃.

Examples 16 to 21

The products of examples 16-21 were prepared in the same manner as in example 14, except that the crystallization reaction time was varied.

The crystallization reaction time of example 16 was 24 h.

The crystallization reaction time of example 17 was 36 h.

The crystallization reaction time of example 18 was 60 h.

The crystallization reaction time of example 19 was 72 h.

The crystallization reaction time of example 20 was 84 h.

The crystallization reaction time of example 21 was 96 h.

Comparative example 1

The preparation method is reported in the literature synthesis of silicoaluminophosphate molecular sieves SAPO-11, SAPO-34 and SAPO-20, and comprises dissolving 3.25g of pseudo-boehmite in 16.8mL of H₂O, and 4.2mL of H was added thereto₃PO₄The solution was stirred for 30min, after which 1.49gSiO were added₂Then, the mixture was stirred for another 30min, and then 9.8mL of TMAOH was added thereto and stirred for 24 h. And then transferring the mixture into a high-pressure reaction kettle, sealing, reacting at 200 ℃ for 120h, taking out a product, washing to be neutral, performing suction filtration and drying to obtain the SAPO-20 zeolite molecular sieve.

The molar ratio of all materials in the system is Al₂O₃:H₂O:P₂O₅:SiO₂:TMAOH＝1.0:40:1.0:1.0:3.75。

The reaction parameters of the above examples and comparative examples are shown in Table 1.

XRD tests were performed on the products of the above examples and comparative examples and the crystallinity was calculated, and the results are shown in Table 1.

TABLE 1 reaction parameters of examples and comparative examples

Results and discussion:

experimental example 1-2 compares whether different silicon sources can synthesize SAPO-20 zeolite in the system, and it can be known from the crystallinity of Table 1 and the XRD pattern of FIG. 1 that SAPO-20 zeolite can be synthesized only by using water glass as the silicon source. In the experiment that only the silicon source is changed and treated under the same hydrothermal condition, silica gel is used as the silicon source (example 1), and the strong diffraction peak of AFX type (SAPO-56) zeolite and the weak diffraction peak of SOD type (SAPO-20) zeolite are observed on the corresponding XRD spectrogram; using water glass as the silicon source (example 2), strong diffraction peaks of the SOD type (SAPO-20) zeolite were observed on the corresponding XRD spectrum. Thus, the present invention balances the cations (i.e., Na) of the negative charge of the backbone⁺) The process of promoting the crystal transformation of the SAPO-56 zeolite into the SAPO-20 has a significant influence.

Experimental examples 2-6 compare whether SAPO-20 zeolite can be synthesized in the system with different phosphorus-silicon ratios, and it can be known from the crystallinity of Table 1 and the XRD pattern of FIG. 2 that SAPO-20 zeolite can be synthesized with a phosphorus-silicon ratio of 0.7-1.0, and the crystallinity of SAPO-20 zeolite synthesized with a phosphorus-silicon ratio of 1.0 is slightly higher than that of SAPO-20 zeolite synthesized with phosphorus-silicon ratios of 0.9, 0.8 and 0.7. Therefore, the phosphorus-silicon ratio of 1.0 is the best mixture ratio.

Experimental examples 6-10 comparing whether SAPO-20 zeolite can be synthesized in the system by different amounts of template agent, it can be seen from the crystallinity of Table 1 and XRD pattern of FIG. 3 that at nTMHD/nP₂O₅SAPO-20 zeolite, nTMHD/nP, can be synthesized when 1.5, 1.4, 1.3, 1.2 and 1.1₂O₅The crystallinity of SAPO-20 zeolite synthesized when the zeolite is 1.2 is higher than nTMHD/nP₂O₅SAPO-20 zeolites synthesized 1.4 and 1.3, thus nTMHD/nP₂O₅The best is 1.2.

Experimental examples 11-15 comparing whether SAPO-20 zeolite can be synthesized in the system at different crystallization temperatures, it can be seen from the crystallinity of Table 1 and the XRD pattern of FIG. 4 that the crystallinity of SAPO-20 zeolite gradually increases with the increase of crystallization temperature. However, at excessively high temperatures, e.g., above 240 ℃, the characteristic peak intensity of the XRD pattern is much lower, and the corresponding crystallinity is considerably lower. Therefore, the crystallization temperature is selected to be 210 ℃ as the optimum temperature.

Example 14 and experimental examples 16 to 21, comparing whether SAPO-20 zeolite can be synthesized in the system with different crystallization times, it can be seen from the crystallinity of table 1 and the XRD pattern of fig. 5 that SAPO-20 can be synthesized with a crystallization time of 36 to 72 hours, and as the crystallization time is increased, the crystallinity of SAPO-20 zeolite is increased and then decreased, and therefore, the optimum crystallization time is selected as 48 hours.

Comparative example 1 and experimental example 14 compare the crystallinity of SAPO-20 zeolite prepared by the prior art synthesis method and the optimal synthesis scheme of the present invention, and it can be known from the crystallinity of table 1 and the XRD spectrum of fig. 6 that the crystallinity of SAPO-20 zeolite is significantly different in different formulations and different material ratios, compared with the literature test scheme, the present invention replaces the silicon source with water glass, replaces the template agent with the synthesis condition of TMHD, and can still synthesize SAPO-20 zeolite with high crystallinity in a shorter hydrothermal time, and the crystallinity of SAPO-20 zeolite synthesized by the present invention reaches 99.99%.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.