Preparation method of high-adsorption-capacity and high-strength LSX molecular sieve under low partial pressure of carbon dioxide

Abstract

The invention discloses a preparation method of a high-adsorption-capacity and high-strength LSX molecular sieve under low partial pressure of carbon dioxide, and belongs to the technical field of molecular sieve preparation. The preparation method of the high-adsorption-capacity and high-strength LSX molecular sieve under the low partial pressure of carbon dioxide comprises the following steps: supplementing water or a colloidal solution into LSX molecular sieve granulation molding waste, mixing and shaping to obtain an LSX molecular sieve granulation sample; and sequentially carrying out roasting and crystallization treatment on the LSX molecular sieve granulation sample to obtain the LSX molecular sieve with high adsorption capacity and high strength under the CO2 low partial pressure. Compared with a molecular sieve product prepared by a traditional production process, the product prepared by the method disclosed by the invention is high in compressive strength, low in abrasion and high in CO2 adsorption capacity under low CO2 partial pressure (2.5-5torr).

Description

Technical Field

[0001] The present invention belongs to the technical field of molecular sieve preparation, and more particularly relates to a method for preparing a high-adsorption-high-strength LSX molecular sieve under low partial pressure of carbon dioxide. Background Art

[0002] During the granulation and molding process of molecular sieve using equipment such as disc granulation, extruder, and high-speed granulator, granulation molding waste will be generated, including dry materials with different water content, flat particles, oversized particles, materials sticking to the bottom of the disc, and materials with unqualified intermediate control process indicators. Currently, manufacturers mainly use the following methods to deal with granulation molding waste: using seed powder machines, seed crushers and other equipment to crush the materials to less than 0.5mm and use them as molecular sieve seeds, and then perform disc granulation to roll the particles to grow to the required qualified particle size. The granulation time is often long and the production efficiency is low.

[0003] Chinese patent CN110237771A discloses a method of first rapidly granulating small core particles using a stirring granulator. These are then coated with a disc granulator by adding a mixed dry material and spraying water, gradually growing the core particles to the desired molecular sieve particle size. This method primarily produces small particles, followed by the addition of a dry mixed powder to adjust the molecular sieve particle size. However, the dry coating method produces a large amount of dust, resulting in low granulation efficiency and low compressive strength.

[0004] Chinese patent CN116493042A discloses a method of using titanium silicalite, a binder and a surfactant as raw materials, first preparing a mixed solution of the surfactant and the siliceous binder, adopting a rapid mixing granulation method, adjusting the moisture content by adding dry powder and rotating at a low speed, and finally using a screening method to prepare molecular sieve particles with a small particle size of 1 to 1.5 mm. The invention first stirs the surfactant and the binder into a mixed solution, and the use of a surfactant increases the cost of raw material preparation, and does not explain how to adjust materials with an unsuitable particle size (less than 1 mm and greater than 1.5 mm) to high-strength molecular sieve particles with a suitable particle size. The method of treating unsuitable particle sizes is not specifically disclosed, and the influence of a high-speed granulator on strength is not involved.

[0005] Chinese patent CN118904199A discloses adding molecular sieve powder, clay, and a water / colloidal solution to an inclined intensive mixer to prepare a block mixture. The block mixture is then supplemented with molecular sieve powder and clay, and fine wet material is added to the wet material with a certain particle size distribution. The mixture is then shaped by a rotating disc to obtain a high-strength, high-sphericity spherical molecular sieve. This method primarily utilizes raw powder and clay as raw materials, then performs high-speed granulation to directly obtain a molecular sieve product of suitable particle size. However, the method for handling unqualified waste is not described.

[0006] Chinese patent CN109485058A discloses a method for preparing a binder-free LSX molecular sieve using LSX molecular sieve powder and kaolin as raw materials. The sieve is directly granulated and formed, then treated with a sodium-potassium mixed alkali solution, subjected to sodium ion exchange, and other processes. The sieve undergoes low-temperature aging and high-temperature crystallization treatments. The method can achieve a carbon dioxide adsorption capacity of 9.5-10.2% at 25°C and a carbon dioxide partial pressure of 4-5 torr. However, the molding strength of the material obtained by this method is low, resulting in low strength and high abrasion of the final product. The increased aging process also causes the crystallization treatment time to be longer.

[0007] Therefore, it is of great significance to prepare a molecular sieve with high adsorption capacity and high strength. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for preparing LSX molecular sieves with high adsorption capacity and high strength under low partial pressure of carbon dioxide, so as to solve the problems existing in the above-mentioned prior art and realize the successful preparation of LSX molecular sieves with high adsorption capacity and high strength under low partial pressure of CO2.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] One of the technical solutions of the present invention is to provide a method for preparing LSX molecular sieve with high adsorption capacity and high strength under low partial pressure of carbon dioxide, comprising the following steps:

[0011] Water or colloidal solution is added to the LSX molecular sieve granulation molding waste, and after mixing and shaping, an LSX molecular sieve granulation sample is obtained; the LSX molecular sieve granulation sample is sequentially calcined and crystallized to obtain the LSX molecular sieve with high adsorption capacity and high strength under low CO2 partial pressure.

[0012] Preferably, the water content of the LSX molecular sieve granulation waste is 15 to 45 wt%, more preferably 25 to 40 wt%.

[0013] Preferably, the amount of water or colloidal solution added is determined by the mass ratio of clay and LSX molecular sieve raw powder during the formation of the LSX molecular sieve granulation molding waste, and the determination method is as follows: the water content of the product obtained after adding water or colloidal solution to the LSX molecular sieve granulation molding waste is 35-50wt%; the clay includes kaolin or halloysite; and the colloidal solution includes one or more of sodium carboxymethyl cellulose aqueous solution, silica sol and water glass solution.

[0014] Furthermore, the solid content of the colloidal solution is 20-40 wt%.

[0015] Furthermore, the mass ratio of clay to LSX molecular sieve raw powder in the process of forming the LSX molecular sieve granulation molding waste is preferably 0.1-0.3:0.7-0.9.

[0016] Furthermore, the method of the present invention is also applicable to other types of molecular sieves such as type A and type X.

[0017] Preferably, the mixing speed is 800-3000 r / min, and the mixing time is 1-23 min; the shaping method includes disc rolling shaping, and the shaping time is 0.5-2 h.

[0018] Preferably, the calcination temperature is 500-650° C., and the calcination time is 0.5-3 h.

[0019] After calcination, the kaolin or halloysite in the molecular sieve is converted into amorphous silicon oxide and aluminum oxide.

[0020] Preferably, the crystallization treatment is carried out in a reagent containing silicon oxide and an alkali; the concentration of silicon oxide in the reagent containing silicon oxide and an alkali is 0.08 to 0.5 mol / L, and the concentration of the alkali is 1 to 4 mol / L; the alkali is sodium hydroxide and / or sodium metaaluminate.

[0021] Preferably, the crystallization treatment is performed at a temperature of 80 to 100° C. and for a time of 3 to 9 hours.

[0022] The crystallization treatment of the present invention is carried out in a crystallization device with uniform temperature and concentration fields, such as a stirred reactor or a tubular reactor.

[0023] After crystallization, amorphous silicon oxide and aluminum oxide are converted into molecular sieves.

[0024] Preferably, the calcined molecular sieve is placed in air for 1 to 3 days before the crystallization treatment.

[0025] The second technical solution of the present invention is to provide an LSX molecular sieve with high adsorption capacity and high strength under low partial pressure of carbon dioxide, which is prepared by the above preparation method.

[0026] The high-strength LSX molecular sieve with high adsorption capacity under low partial pressure of carbon dioxide prepared by the present invention has a compressive strength of ≥50N, a wear loss of ≤0.01wt%, and a CO2 adsorption capacity of 9.3-11.5wt% at 15°C and 2.5-5torr.

[0027] The technical mechanism of the present invention is as follows:

[0028] The method of the present invention can significantly improve the compressive strength of the obtained LSX molecular sieve. Specifically, the LSX molecular sieve granulation waste is re-crushed into small particles with a certain strength after high-speed rotation. Then, the small particles gradually seep out water during the process of re-growth during extrusion, which increases the extrusion density of the finally formed LSX molecular sieve and improves the compressive strength of the LSX molecular sieve.

[0029] The method of the present invention can significantly improve the CO2 adsorption capacity of the obtained LSX molecular sieve under low CO2 partial pressure. Specifically, after crystallization, the LSX molecular sieve granulation sample generates high-purity 0.5-2μm X-type molecular sieve fine crystals, which is beneficial to improving the low-partial-pressure carbon dioxide adsorption capacity.

[0030] The present invention discloses the following technical effects:

[0031] (1) The traditional method mainly uses molecular sieve waste as seeds and then adds mixed powder for granulation and molding. The molecular sieve granulation molding time period is long and the granulation molding strength is low. The present invention adjusts the water content or colloidal solution content in the granulation molding and uses a high-speed granulator for rapid molding, and the high-speed granulation time is short. In addition, when the high-speed granulator is used to break the waste, small particles with a certain hardness are re-aggregated and extruded, which can significantly improve the compressive strength.

[0032] (2) The process flow of the present invention is simple. After granulation and molding, high-temperature crystallization treatment is directly adopted without low-temperature aging treatment. The crystallization treatment time is short, which significantly reduces the production cycle. At the same time, since concentration and temperature fluctuations have a great influence on the crystallization of molecular sieves, the use of crystallization devices with uniform temperature and concentration fields such as stirred reactors and tubular reactors can avoid the influence of concentration and temperature fluctuations on the adsorption performance of molecular sieves during the crystallization process of the material, thereby maintaining the stability of product performance.

[0033] (3) Compared with the molecular sieve products prepared by the traditional production process, the product of the present invention has high compressive strength, low abrasion, and high CO2 adsorption capacity under low CO2 partial pressure (2.5 to 5 torr). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The CO2 adsorption capacity of the LSX molecular sieve prepared in Example 1 at 15°C and 2.5-5 torr. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0037] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0038] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0041] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are all commercially available products, and the sources of the commercially available products do not affect the technical effects of the present invention.

[0042] The compressive strength of the LSX molecular sieve prepared in the present invention is tested according to HGT 2783-2020; the water adsorption and abrasion of the LSX molecular sieve are tested according to GB / T 13550-2015; and the CO2 adsorption capacity of the LSX molecular sieve is tested using a physical adsorption instrument.

[0043] The crystallization treatment described in the following examples and comparative examples of the present invention was carried out in a tubular reactor.

[0044] Example 1

[0045] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.15:0.85, and after high-speed granulation and molding, take particles with a particle size greater than 2.5 mm (not meeting product requirements), which are the granulation molding waste.

[0046] Take 60 kg of granulation molding waste (water content is 30 wt%), add 16 kg of water, first adjust the high-speed granulator parameters to 2500 r / min for 2 minutes, then adjust the high-speed granulator parameters to 900 r / min for 15 minutes, after disc rolling shaping for 0.5 hours, calcined at 600 ° C for 2 hours; the calcined molecular sieve is placed in air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.2 mol / L and a sodium hydroxide concentration of 1.5 mol / L, and crystallized at 80 ° C for 9 hours to obtain a 1.6-2.5 mm LSX molecular sieve product.

[0047] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 57N, the water absorption of the molded product accounts for 98.5wt% of the water absorption of the pure original powder, the abrasion is 0.01wt%, and the CO2 adsorption capacity is 9.7-11.5wt% at 15°C and 2.5-5torr.

[0048] Example 2

[0049] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.15:0.85, and after high-speed granulation and molding, take particles with a particle size of less than 1 mm (not meeting product requirements), which are the granulation molding waste.

[0050] Take 60 kg of granulation molding waste (water content is 25wt%), add 18 kg of water, first adjust the high-speed granulator parameters to 2000r / min for 3 minutes, then adjust the high-speed granulator parameters to 800r / min for 20 minutes, after disc rolling shaping for 0.5 hours, calcined at 600℃ for 2 hours; the calcined molecular sieve is placed in air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.15mol / L and a sodium hydroxide concentration of 1.75mol / L, and crystallized at 90℃ for 7 hours to obtain a 1.6-2.5mm LSX molecular sieve product.

[0051] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 55N, the water absorption of the molded product accounts for 99wt% of the water absorption of the pure original powder, the abrasion is 0.01wt%, and the CO2 adsorption capacity is 9.8-11.3wt% at 15°C and 2.5-5torr.

[0052] Example 3

[0053] The difference from Example 1 is that the water supplement in Example 1 is replaced by the supplement of 16 kg of a colloidal solution containing 30 wt% silica sol, and the concentration of silicon oxide in the alkali solution is adjusted to 0.1 mol / L. The remaining steps are the same as in Example 1.

[0054] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 55N, the water absorption of the molded product accounts for 98wt% of the water absorption of the pure original powder, the abrasion is 0.01wt%, and the CO2 adsorption capacity is 9.5-11wt% at 15°C and 2.5-5torr.

[0055] Example 4

[0056] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.2:0.8, and after high-speed granulation and molding, take particles with a particle size of less than 1mm (not meeting product requirements), which are the granulation molding waste.

[0057] Take 60 kg of granulation molding waste (water content is 25wt%), add 13 kg of water, first adjust the high-speed granulator parameters to 1800 r / min for 3 minutes, then adjust the high-speed granulator parameters to 900 r / min for 15 minutes, after disc rolling shaping for 1 hour, calcined at 550°C for 2 hours; the calcined molecular sieve is placed in air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.17 mol / L and a sodium hydroxide concentration of 1.75 mol / L, and crystallized at 90°C for 7 hours to obtain a 1.6-2.5 mm LSX molecular sieve product.

[0058] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 65N, the water absorption of the molded product accounts for 97wt% of the water absorption of the pure original powder, the abrasion is 0.006wt%, and the CO2 adsorption capacity is 9.5-11wt% at 15°C and 2.5-5torr.

[0059] Example 5

[0060] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.2:0.8, and after high-speed granulation and molding, take particles with a particle size greater than 2.5 mm (not meeting product requirements), which are the granulation molding waste.

[0061] Take 60 kg of granulation molding waste (water content of 33 wt%), add 15 kg of water, first adjust the high-speed granulator parameters to 2000 r / min for 2 minutes, then adjust the high-speed granulator parameters to 1100 r / min for 8 minutes, and after disc rolling shaping for 1 hour, calcinate at 550 ° C for 2 hours; the calcined molecular sieve is placed in the air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.15 mol / L and a sodium hydroxide concentration of 2.25 mol / L, and crystallized at 80 ° C for 7 hours to obtain a 1.6-2.5 mm LSX molecular sieve product.

[0062] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 70N, the water absorption of the molded product accounts for 97wt% of the water absorption of the pure original powder, the abrasion is 0.005wt%, and the CO2 adsorption capacity is 9.5-11wt% at 15°C and 2.5-5torr.

[0063] Example 6

[0064] The difference from Example 4 is that the water supplement in Example 4 is replaced by 13 kg of water glass (wherein the SiO2 content is 29 wt% and the Na2O content is 9 wt%), and the silicon oxide concentration in the alkali solution is adjusted to 0.07 mol / L. The remaining steps are the same as in Example 4.

[0065] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 60N, the water absorption of the molded product accounts for 96.5wt% of the water absorption of the pure original powder, the abrasion is 0.006wt%, and the CO2 adsorption capacity is 9.3-11wt% at 15°C and 2.5-5torr.

[0066] Comparative Example 1: After the seeds were prepared from the granulation waste, they were granulated by a disc

[0067] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.15:0.85, and after high-speed granulation and molding, take particles with a particle size greater than 2.5 mm (not meeting product requirements), which are the granulation molding waste.

[0068] 20 kg of granulation waste (water content of 30%) was taken and crushed into seeds (crushed to less than 0.5 mm) using a crusher for 0.5 h. Water was added to the dry mixture while disc rolling was performed. After 18 h of disc rolling, molded molecular sieve balls were prepared with a final water content of 39%. The calcined molecular sieve was placed in air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.2 mol / L and a sodium hydroxide concentration of 1.5 mol / L, and crystallized at 80 ° C for 9 h to obtain a 1.6-2.5 mm LSX molecular sieve product.

[0069] After testing, the compressive strength of the LSX molecular sieve obtained in this comparative example is 35N, the water absorption of the molded product accounts for 98.5wt% of the water absorption of the pure original powder, the abrasion is 0.03wt%, and the CO2 adsorption capacity is 9.0-10wt% at 15°C and 2.5-5torr.

[0070] Comparison of Example 1 with Comparative Example 1 shows that the crystallized sample obtained by the disc rolling granulation method after preparing seeds using granulation waste has low compressive strength, high abrasion, and requires a long granulation time. In addition, the method described in Comparative Example 1 requires 18 hours of granulation time to process 20 kg of granulation waste, while the method described in Example 1 only requires 0.5 hours of granulation time to process 60 kg of granulation waste. This shows that the method of the present invention can greatly save granulation time and increase the processing capacity of granulation waste.

[0071] Comparative Example 2: Using molecular sieve powder and clay for high-speed granulation and then disc rolling shaping

[0072] The molecular sieve raw powder, clay and water are added into an inclined strong mixer in a ratio of 0.85:0.15:0.45, and processed at 2500r / min for 2min. Then, the high-speed granulator parameters are adjusted to 900r / min for 15min. After disc rolling shaping for 0.5h, the disc shaping and rolling are used to prepare the formed molecular sieve balls. The adsorption saturated sample after drying and calcining is introduced into a high-temperature alkaline solution with a silicon oxide concentration of 0.2mol / L and a sodium hydroxide concentration of 1.5mol / L, and crystallized at 80℃ for 9h to obtain a 1.6-2.5mm product.

[0073] After testing, the compressive strength of the product obtained in this comparative example is 40N, the water absorption of the molded product accounts for 98.5wt% of the water absorption of the pure original powder; the abrasion is 0.02wt%, and the CO2 adsorption capacity is 9-10wt% at 15°C and 2.5-5torr.

[0074] Comparison of Example 1 and Comparative Example 2 shows that after high-speed granulation of molecular sieve raw powder and clay, the crystallized sample has low compressive strength and high abrasion compared with high-speed granulation of waste materials.

[0075] Comparative Example 3: Low temperature aging treatment first, then crystallization treatment

[0076] Take kaolin and LSX molecular sieve raw powder with a mass ratio of 0.15:0.85, and after high-speed granulation and molding, take particles with a particle size greater than 2.5 mm (not meeting product requirements), which are the granulation molding waste.

[0077] Take 60 kg of granulation molding waste (water content is 30 wt%), add 16 kg of water, first adjust the high-speed granulator parameters to 2500 r / min for 2 minutes, then adjust the high-speed granulator parameters to 900 r / min for 15 minutes, after disc rolling shaping for 0.5 hours, calcined at 600 ° C for 2 hours; the calcined molecular sieve is placed in air for 3 days, and then placed in an alkaline solution with a silicon oxide concentration of 0.2 mol / L and a sodium hydroxide concentration of 1.5 mol / L, first low-temperature aging at 50 ° C for 2 hours, and then crystallization treatment at 80 ° C for 8 hours to obtain a 1.6-2.5 mm LSX molecular sieve product.

[0078] After testing, the compressive strength of the LSX molecular sieve obtained in this embodiment is 45N, the water absorption of the molded product accounts for 97wt% of the water absorption of the pure original powder, the abrasion is 0.03wt%, and the CO2 adsorption capacity is 8.8-9.8wt% at 15°C and 2.5-5torr.

[0079] By comparing Example 1 with Comparative Example 3, it can be seen that the low-temperature aging treatment reduces the adsorption capacity and compressive strength of the molecular sieve, which is not conducive to the production of a molecular sieve with a high adsorption capacity.

[0080] Comparative Example 4 Commercially available LSX molecular sieve product

[0081] After testing, the compressive strength of the commercially available LSX molecular sieve product is 31N, the water absorption of the molded product accounts for 96wt% of the water absorption of the pure original powder, the abrasion is 0.04wt%, and the CO2 adsorption capacity is 8.5-10wt% at 15°C and 2.5-5torr.

[0082] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0083] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-strength LSX molecular sieve with high adsorption capacity at low partial pressure of carbon dioxide, characterized in that: The steps include: Water or colloidal solution is added to the LSX molecular sieve granulation molding waste, and the mixture is mixed and shaped to obtain an LSX molecular sieve granulation sample; the LSX molecular sieve granulation sample is sequentially calcined and crystallized to obtain the LSX molecular sieve with high adsorption capacity and high strength under low partial pressure of carbon dioxide.

2. The preparation method according to claim 1, characterized in that The water content of the LSX molecular sieve granulation waste is 15-45wt%.

3. The preparation method according to claim 1, characterized in that The amount of water or colloidal solution added is determined by the mass ratio of clay and LSX molecular sieve raw powder during the formation of the LSX molecular sieve granulation molding waste, and the determination method is as follows: the water content of the product obtained after adding water or colloidal solution to the LSX molecular sieve granulation molding waste is 35-50wt%; the clay includes kaolin or halloysite; and the colloidal solution includes one or more of sodium carboxymethyl cellulose aqueous solution, silica sol and water glass solution.

4. The preparation method according to claim 1, characterized in that The mixing speed is 800-3000 r / min, and the mixing time is 1-23 min; and / or the shaping method includes disc rolling shaping, and the shaping time is 0.5-2 h.

5. The preparation method according to claim 1, characterized in that The calcination temperature is 500-650° C., and the calcination time is 0.5-3 hours.

6. The preparation method according to claim 1, characterized in that The crystallization treatment is carried out in a reagent containing silicon oxide and alkali; the concentration of silicon oxide in the reagent containing silicon oxide and alkali is 0.08-0.5 mol / L, and the concentration of alkali is 1-4 mol / L; the alkali is sodium hydroxide and / or sodium metaaluminate.

7. The preparation method according to claim 6, characterized in that The crystallization treatment is performed at a temperature of 80 to 100° C. and for a time of 3 to 9 hours.

8. The preparation method according to claim 1, characterized in that The crystallization process also includes a step of absorbing water to a saturated state on the molecular sieve obtained by calcination before the crystallization process.

9. The LSX molecular sieve with high adsorption capacity and high strength at low carbon dioxide partial pressure prepared by the preparation method according to any one of claims 1 to 8.

10. The LSX molecular sieve with high adsorption capacity and high strength at low partial pressure of carbon dioxide according to claim 9, characterized in that: The high-adsorption capacity and high-strength LSX molecular sieve at low carbon dioxide partial pressure has a compressive strength of ≥50N, an abrasion loss of ≤0.01wt%, and a CO2 adsorption capacity of 9.3-11.5wt% at 15°C and 2.5-5 torr.

Images