13X zeolite molecular sieve combining crystallization process and forming process and preparation method thereof

Abstract

The invention relates to the technical field of zeolite molecular sieve preparation, in particular to a 13X zeolite molecular sieve combining a crystallization process and a forming process and a preparation method. The preparation method comprises the following steps: mixing a silicate solution and an aluminate solution to obtain mixed gel; mixing a 13X zeolite molecular sieve seed crystal with the mixed gel to obtain a gel mixed raw material; carrying out gradient crystallization on the gel mixed raw material to obtain a crystallization solution with a regular octahedral solid-phase substance; wherein the gradient crystallization comprises first crystallization, second crystallization and third crystallization, and the temperature of the first crystallization is larger than or equal to the temperature of the third crystallization and smaller than or equal to the temperature of the second crystallization; and sequentially washing, filtering and drying the crystallization liquid to obtain 13X zeolite molecular sieve raw powder. According to the preparation method, through the synergistic effect of three-stage crystallization temperature gradient innovation, a seed crystal directional induction mechanism and a defect regulation and control process, the stacking density of the 13X zeolite molecular sieve is finally remarkably improved.

Description

Technical Field

[0001] This application relates to the field of zeolite molecular sieve preparation technology, and in particular to a 13X zeolite molecular sieve combining crystallization and molding processes and its preparation method. Background Technology

[0002] 13X zeolite molecular sieves are an important branch of octahedral zeolite structures. The silica-to-alumina ratio of 13X zeolite molecular sieves is typically between 2.0 and 3.0, and they possess uniform pore size (approximately 1.0 nm) and a large specific surface area (≥650 m²). 2 Due to its excellent adsorption performance and ion exchange capacity, 13X zeolite molecular sieve is currently widely used in applications such as feed gas purification (removal of H2O, CO2 and hydrocarbons), natural gas desulfurization, and liquid hydrocarbon drying in air separation equipment.

[0003] The bulk density (or packing ratio) is a key industrial indicator for 13X zeolite molecular sieves, directly affecting the packing efficiency of equipment and the adsorption capacity per unit volume of zeolite molecular sieve. However, the bulk density of 13X zeolite molecular sieves is currently generally below 0.65 g / cm³. 3 This affects the use of 13X zeolite molecular sieve. Summary of the Invention

[0004] This application provides a 13X zeolite molecular sieve combining crystallization and molding processes and its preparation method to solve the following technical problem: how to improve the bulk density of 13X zeolite molecular sieve. In a first aspect, embodiments of this application provide a method for preparing 13X zeolite molecular sieves that combines crystallization and molding processes, the preparation method comprising: A silicate solution and an aluminate solution are mixed to obtain a mixed gel; The 13X zeolite molecular sieve seed crystals and the mixed gel were mixed to obtain a gel mixture raw material; The gel mixture is subjected to gradient crystallization to obtain a crystallized liquid with a regular octahedral solid phase; wherein the gradient crystallization includes a first crystallization, a second crystallization and a third crystallization, and the temperature of the first crystallization is ≤ the temperature of the third crystallization is ≤ the temperature of the second crystallization; The crystallization solution was washed, filtered, and dried sequentially to obtain 13X zeolite molecular sieve raw powder.

[0005] Optionally, the temperature of the first crystallization is 60°C to 70°C; and / or The second crystallization temperature is 80°C to 90°C; and / or The temperature for the third crystallization is 70°C to 80°C.

[0006] Optionally, the first crystallization time is 4 hours to 6 hours; and / or The second crystallization time is 6 to 8 hours; and / or The third crystallization time is 2 to 3 hours.

[0007] Optionally, the silicate solution uses silicon dioxide as the first solid phase and the aluminate solution uses aluminum oxide as the second solid phase, wherein the amount of the first solid phase n1 and the amount of the second solid phase n2 satisfy: n1:n2 = (2 to 3): (0.9 to 1.1).

[0008] Optionally, the mass of the first solid phase is 20% to 30% of the mass of the silicate solution.

[0009] Optionally, the mass m1 of the second solid and the volume V1 of the aluminate solution satisfy: m1:V1 = (50 to 80):1, and if the unit of m1 is g, then V1 is L.

[0010] Optionally, the particle size of the 13X zeolite molecular sieve seed crystals is 1 μm to 3 μm; and / or The mass m2 of the 13X zeolite molecular sieve seed crystals and the mass m3 of the mixed gel satisfy the following condition: m2:m3 = (1.5 to 2.5):100.

[0011] Optionally, the size of the octahedral solid phase in the crystallization solution having a regular octahedral solid phase is 3.5 μm to 4.5 μm.

[0012] Optionally, the drying temperature is between 80°C and 110°C.

[0013] Secondly, embodiments of this application provide a 13X zeolite molecular sieve combining crystallization and molding processes. The 13X zeolite molecular sieve is obtained by the preparation method described in the first aspect, and its bulk density is 0.72 g / cm³. 3 Up to 0.80 g / cm 3 The static water adsorption capacity of the 13X zeolite molecular sieve is ≥28%, and the specific surface area of ​​the 13X zeolite molecular sieve is ≥650 m². 2 / g.

[0014] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for preparing 13X zeolite molecular sieves that combines crystallization and molding processes. The method first uses a silicate solution as the silicon source and an aluminate solution as the aluminum source, mixing them to induce a hydrolysis reaction and form a mixed gel. Then, 13X zeolite molecular sieve seed crystals are mixed with the mixed gel to obtain a gel-mixed raw material. A gradient crystallization process is then applied to the gel-mixed raw material: the first stage involves low-temperature crystallization combined with the directional induction effect of the 13X seed crystals, promoting the directional generation of 13X zeolite molecular sieve nuclei; the second stage involves high-temperature crystallization, which promotes the synchronous and rapid growth of the nuclei, improving the stacking efficiency; the third stage involves cooling and heat preservation, during which the aluminosilicate species in the crystallization liquid slowly repair the irregular structure on the crystal surface, improving the uniformity of crystal size distribution and effectively reducing ineffective voids during stacking, ultimately forming a crystallization liquid containing regular octahedral solid phases; finally, after washing, filtration, and drying, 13X zeolite molecular sieve raw powder with a regular octahedral morphology is obtained. Therefore, this preparation method optimizes the structure from three dimensions: crystal size uniformity, particle morphology, and internal density, significantly improving the bulk density of the 13X zeolite molecular sieve powder. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a method for preparing 13X zeolite molecular sieve that combines crystallization and molding processes, provided as an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared by existing methods.

[0020] It should be noted that the preparation of 13X zeolite molecular sieves currently faces the following main technical bottlenecks: (1) High dispersion of primary crystals during crystallization: Traditional single-stage crystallization process (80℃ to 100℃ constant temperature crystallization for 8h to 12h) easily leads to uneven size of primary crystals (1μm to 2μm), and a large number of irregular gaps are easily formed when the crystals are stacked, making it difficult to build a dense stacked structure; (2) High crystal defect rate: The existing segmented crystallization technology lacks a defect control link, and micropore defects are easily generated inside the crystal, which reduces the density of the original crystal and affects the improvement of the packing density of 13X zeolite molecular sieve. (3) Poor controllability of primary crystal morphology: Under traditional processes, the growth direction of 13X zeolite molecular sieve crystals is random, resulting in irregular morphology of 13X zeolite molecular sieves. This further increases the packing gap of 13X zeolite molecular sieves, leading to a general bulk density of 13X zeolite molecular sieve powder that is lower than 0.65 g / cm³. 3 .

[0021] In view of the shortcomings of the existing methods for preparing 13X zeolite molecular sieves, the embodiments of this application provide the following technical solutions: Figure 1 An exemplary schematic diagram of a method for preparing 13X zeolite molecular sieve combining crystallization and molding processes provided in this application embodiment is shown. like Figure 1 As shown in the embodiments of this application, a method for preparing 13X zeolite molecular sieve combining crystallization and molding processes is provided. The preparation method includes: S1. Mix the silicate solution and the aluminate solution to obtain a mixed gel; S2. Mix the 13X zeolite molecular sieve seed crystals and the mixed gel to obtain a gel mixture raw material; S3. The gel mixture is subjected to gradient crystallization to obtain a crystallized liquid with a regular octahedral solid phase; wherein the gradient crystallization includes a first crystallization, a second crystallization and a third crystallization, and the temperature of the first crystallization is ≤ the temperature of the third crystallization is ≤ the temperature of the second crystallization; S4. The crystallization liquid is washed, filtered and dried sequentially to obtain 13X zeolite molecular sieve powder.

[0022] It should be noted that the mixing process of silicate solution and aluminate solution can be carried out under stirring conditions, and this mixing process can last for 30 minutes.

[0023] It should be noted that the first crystallization and the second crystallization can be carried out under stirring conditions, and the stirring speed during the first crystallization and the second crystallization can be 30 r / min.

[0024] It should be noted that this application provides a method for preparing 13X zeolite molecular sieves that combines crystallization and molding processes. This method, through the synergistic effect of a three-stage crystallization temperature gradient innovation, a seed-directed induction mechanism, and a defect control process, constructs a high-density structural foundation from three core dimensions: crystal size and distribution, particle morphology, and internal structure, ultimately achieving a significant increase in the packing density of 13X zeolite molecular sieves. The specific mechanism is as follows: I. Innovation of three-stage crystallization temperature gradient: laying the foundation for the high packing density size and distribution of 13X zeolite molecular sieves.

[0025] This preparation method is designed with a temperature curve of low-temperature directional nucleation → high-temperature uniform growth → low-temperature defect elimination, which directly optimizes the stacking efficiency from both the aspects of crystal size and uniformity.

[0026] 1. Low-temperature directional nucleation (first crystallization, lowest temperature): The low-temperature conditions of the first crystallization allow the crystal nucleus generation rate of 13X zeolite molecular sieve to be slow and controllable, avoiding excessive and disordered generation of 13X zeolite molecular sieve crystal nuclei, ensuring that the number of crystal nuclei in the crystallization solution is moderate and the initial size is consistent, laying the foundation for the uniform growth of 13X zeolite molecular sieve crystals and reducing the problem of inconsistent crystal size caused by differences in crystal nucleus size.

[0027] 2. High-Temperature Uniform Growth (Second Crystallization, Highest Temperature): The high temperature of the second crystallization provides sufficient power for the crystal growth of 13X zeolite molecular sieves, enabling the crystal nuclei of 13X zeolite molecular sieves to grow synchronously and rapidly, resulting in a 40% to 50% increase in crystal size compared to traditional single-stage crystallization. Furthermore, during the stacking stage of larger 13X zeolite molecular sieve crystals, the proportion of small voids between 13X zeolite molecular sieve particles decreases, making it easier to fill the gaps between larger particles and improving the stacking efficiency of 13X zeolite molecular sieves.

[0028] 3. Low-Temperature Defect Elimination (Third Crystallization, temperature between the first and second crystallization): During the cooling and holding process of the third crystallization, the crystal growth rate of 13X zeolite molecular sieve slows down. The aluminosilicate species in the crystallization liquid system can slowly repair the irregular structure on the crystal surface, improving the uniformity of crystal size distribution. The uniform crystal size of the 13X zeolite molecular sieve avoids bridging or voids when small crystals fill the gaps between large crystals, resulting in a more compact particle arrangement and effectively reducing ineffective voids in the packing.

[0029] II. Seed orientation induction mechanism: Optimize particle morphology to reduce packing gaps.

[0030] 13X zeolite molecular sieve seed crystals of a specific size can provide a clear orientation template for crystal growth, guiding the 13X zeolite molecular sieve crystals to grow along a specific orientation crystal plane and form a regular octahedral shape. This is a key structural optimization step to reduce packing gaps.

[0031] 1. Directed crystal face growth: The lattice structure and surface energy characteristics of the seed crystals promote the preferential deposition of silicon and aluminum species in the gel on specific crystal faces, inhibiting the growth of other random crystal faces, and ultimately forming a well-structured octahedral crystal. The octahedral particles have a more regular geometry, and compared with irregularly shaped crystals, the contact between particles is closer during stacking, and the gaps are more easily "filled".

[0032] 2. Reduced packing gaps: When 13X zeolite molecular sieve particles are packed in regular octahedral form, the ineffective gaps between the particles are reduced by 15% to 20%. This reduction in gaps directly translates to an increase in the crystal mass of 13X zeolite molecular sieve that can be accommodated per unit volume, thus increasing the packing density of the 13X zeolite molecular sieve. For example, wedge-shaped or conical voids that may form when irregular particles are packed are significantly compressed in regular octahedral packing.

[0033] III. Defect Control Process: Increasing the crystal density of 13X zeolite molecular sieve to strengthen the support of the packing structure.

[0034] The cooling and holding stages of the three-stage crystallization process (third crystallization) also have the function of defect elimination. It can improve the density by starting from the internal structure of the 13X zeolite molecular sieve crystal, and provide structural guarantee for the packing density.

[0035] 1. Elimination of microporous defects: Under low-temperature conditions, the atomic diffusion rate of 13X zeolite molecular sieve crystals is moderate, which can gradually fill internal defects such as micropores and lattice vacancies formed during crystal growth, eliminating more than 50% of the microporous defects inside the crystal. The reduction of internal defects leads to a decrease in the porosity of the 13X zeolite molecular sieve crystals themselves, resulting in a smaller crystal volume per unit mass and the ability to accommodate more crystals in the same packing space.

[0036] 2. Improved Original Crystal Density: After defect elimination, the atomic arrangement of the 13X zeolite molecular sieve crystals is more compact, increasing the original crystal density by 20% to 25%. With higher density, the 13X zeolite molecular sieve particles are less prone to deformation during the packing stage, maintaining a stable geometric shape. This avoids loose packing structures caused by crystal compression and deformation, and reduces false density issues due to internal crystal porosity, ensuring a genuine increase in the packing density of the 13X zeolite molecular sieve.

[0037] IV. The final effect of synergy The three mechanisms—the three-stage crystallization temperature gradient, the seed-directed induction mechanism, and the defect control process—are not isolated, but... They promote each other and work together to increase packing density: 1. Three-stage crystallization temperature gradient: (1) Core function: to optimize the crystal size and uniformity of 13X zeolite molecular sieve; (2) Contribution to packing density: Reduces voids caused by the difference in grain size of 13X zeolite molecular sieve, and improves packing efficiency; (3) Synergistic effect: It provides a basis for the directional growth of 13X zeolite molecular sieve seed crystals with controllable size and creates temperature conditions for defect elimination.

[0038] 2. Seed orientation induction: (1) Core function: to form a regular octahedral morphology; (2) Contribution to bulk density: Reduces ineffective interparticle gaps in 13X zeolite molecular sieves by 15% to 20%; (3) Synergistic effect: The regular morphology makes the crystals of 13X zeolite molecular sieve with uniform size more compact, amplifying the advantage of size uniformity.

[0039] 3. Defect control process: (1) Core function: to improve the crystal density of 13X zeolite molecular sieve; (2) Contribution to packing density: Reduced internal defects increase the crystal mass per unit volume of 13X zeolite molecular sieve; (3) Synergistic effect: Dense crystals enhance the stability of the stacked structure and avoid new voids caused by crystal breakage during stacking.

[0040] In summary, this application provides a method for preparing 13X zeolite molecular sieves that combines crystallization and molding processes. This method utilizes three mechanisms—a three-stage crystallization temperature gradient, a seed-directed induction mechanism, and a defect control process—to achieve a significant increase in the packing density of 13X zeolite molecular sieves. Compared to traditional preparation methods, this method provides reliable support for high packing density in terms of crystal size, morphology, and internal structure.

[0041] In some alternative embodiments, the temperature of the first crystallization is 60°C to 70°C; and / or The second crystallization temperature is 80°C to 90°C; and / or The temperature for the third crystallization is 70°C to 80°C.

[0042] In these embodiments, the first crystallization at a temperature of 60°C to 70°C can be conducted in a low-temperature environment. This low-temperature environment allows for a slow and controllable nucleus generation rate of the 13X zeolite molecular sieve, ensuring a moderate number and initially uniform size of nuclei in the crystallization solution, laying the foundation for the subsequent uniform growth of 13X zeolite molecular sieve crystals. The second crystallization at a temperature of 80°C to 90°C can be conducted in a high-temperature environment. This high-temperature environment allows for synchronous and rapid growth of 13X zeolite molecular sieve nuclei, and facilitates the filling of gaps between large particles, thereby improving the packing efficiency of the 13X zeolite molecular sieve. Furthermore, the third crystallization at a temperature of 70°C to 80°C can be conducted during a cooling and heat preservation process, slowing down the crystal growth rate of the 13X zeolite molecular sieve, improving the uniformity of crystal size distribution, and resulting in a denser particle arrangement, effectively reducing ineffective voids in the packing.

[0043] The temperature for the first crystallization can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, or 70°C.

[0044] The temperature for the second crystallization can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃ or 90℃.

[0045] The temperature for the third crystallization can be 70℃, 71℃, 72℃, 73℃, 74℃, 75℃ or 80℃.

[0046] It should be noted that the temperature for the first crystallization can be 65°C to 68°C; the temperature for the second crystallization can be 83°C to 87°C; and the temperature for the third crystallization can be 74°C to 77°C.

[0047] In some alternative embodiments, the first crystallization time is 4 hours to 6 hours; and / or The second crystallization time is 6 to 8 hours; and / or The third crystallization time is 2 to 3 hours.

[0048] In these embodiments, the first crystallization, lasting 4 to 6 hours, allows for a slow and controllable nucleus generation rate of the 13X zeolite molecular sieve, ensuring a moderate number and initially uniform size of nuclei in the crystallization solution, laying the foundation for uniform crystal growth of the subsequent 13X zeolite molecular sieve. Furthermore, the second crystallization, lasting 6 to 8 hours, enables synchronous and rapid growth of the 13X zeolite molecular sieve nuclei and facilitates the filling of gaps between large particles, thereby improving the packing efficiency of the 13X zeolite molecular sieve. Additionally, the third crystallization, lasting 2 to 3 hours, slows down the crystal growth rate of the 13X zeolite molecular sieve, improves the uniformity of crystal size distribution, and results in a more compact particle arrangement, effectively reducing ineffective voids in the packing.

[0049] The time for the first crystallization can be 4h, 4.5h, 5.0h, 5.5h or 6.0h.

[0050] The second crystallization time can be 6h, 6.5h, 7.0h, 7.5h or 8.0h.

[0051] The time for the third crystallization can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h or 3.0h.

[0052] In some optional embodiments, the silicate solution uses silicon dioxide as the first solid phase and the aluminate solution uses aluminum oxide as the second solid phase, wherein the amount of the first solid phase n1 and the amount of the second solid phase n2 satisfy: n1:n2 = (2 to 3): (0.9 to 1.1).

[0053] In these embodiments, silicon dioxide in a silicate solution is used as the first solid phase, and aluminum oxide in an aluminate solution is used as the second solid phase. The first solid phase and the second solid phase are in a molar ratio of (2 to 3): (0.9 to 1.1), which allows for sufficient hydrolysis between the silicate solution and the aluminate solution to form a dense mixed gel, which is beneficial for subsequent gradient crystallization.

[0054] The amount of substance n1 of the first solid phase can be 2, 2.1, 2.2, 2.3, 2.4, 2.5 or 3.0.

[0055] The amount of substance n2 of the second solid phase can be 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 1.00, 1.05 or 1.10.

[0056] In some alternative embodiments, the mass of the first solid phase is 20% to 30% of the mass of the silicate solution.

[0057] In these embodiments, the first solid phase, which is 20% to 30% of the mass of the silicate solution, ensures that the silicate solution contains sufficient silica, which facilitates sufficient hydrolysis between the silicate and aluminate solutions and the formation of a dense mixed gel.

[0058] The mass of the first solid phase can be 20%, 21%, 22%, 23%, 24%, 25%, or 30% of the mass of the silicate solution.

[0059] It should be noted that the mass of the first solid phase can be 23% to 28% of the mass of the silicate solution.

[0060] In some alternative embodiments, the mass m1 of the second solid phase and the volume V1 of the aluminate solution satisfy: m1:V1 = (50 to 80):1, and if the unit of m1 is g, then V1 is L.

[0061] In these embodiments, the ratio of the mass of the second solid to the volume of the aluminate solution is (50 to 80):1, which allows the aluminate solution to contain sufficient alumina, which is beneficial for the thorough hydrolysis between the silicate solution and the aluminate solution, and the formation of a dense mixed gel.

[0062] The mass m1 of the second solid phase can be 50, 51, 52, 53, 54, 55, 60, 65, 70, 75 or 80.

[0063] It should be noted that the ratio of the mass of the second solid phase to the volume of the aluminate solution can be (60 to 70):1.

[0064] In some optional embodiments, the 13X zeolite molecular sieve seed crystals have a particle size of 1 μm to 3 μm; and / or The mass m2 of the 13X zeolite molecular sieve seed crystals and the mass m3 of the mixed gel satisfy the following condition: m2:m3 = (1.5 to 2.5):100.

[0065] In these embodiments, 13X zeolite molecular sieve seed crystals with a particle size of 1 μm to 3 μm have a high specific surface area, which can provide a clear orientation template for crystal growth, guiding the 13X zeolite molecular sieve crystals to grow along specific orientation crystal faces, forming a regular octahedral shape, which is beneficial for forming 13X zeolite molecular sieve raw powder with high packing density. In addition, a mass ratio of 13X zeolite molecular sieve seed crystals and mixed gel of (1.5 to 2.5):100 allows the mixed gel to grow along specific orientation crystal faces under the orientation effect of the 13X zeolite molecular sieve seed crystals, forming a regular octahedral shape, which is beneficial for forming 13X zeolite molecular sieve raw powder with high packing density.

[0066] The particle size of the 13X zeolite molecular sieve seed crystals can be 1μm, 1.5μm, 2μm, 2.5μm or 3μm.

[0067] The mass m2 of the 13X zeolite molecular sieve seed crystal can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 or 2.5.

[0068] It should be noted that the particle size of the 13X zeolite molecular sieve seed crystals can be from 1.3 μm to 2.0 μm.

[0069] In some alternative embodiments, the size of the octahedral solid phase in the crystallization liquid is 3.5 μm to 4.5 μm.

[0070] In these embodiments, the presence of octahedral solids with a size of 3.5 μm to 4.5 μm in the crystallization solution indicates that the gradient crystallization process has resulted in well-formed 13X zeolite molecular sieve crystals without internal defects, which is beneficial for the subsequent formation of high-density 13X zeolite molecular sieve raw powder.

[0071] The size of the octahedral solid phase in the crystallization solution can be 3.5μm, 3.6μm, 3.7μm, 3.8μm, 3.9μm, 4.0μm or 4.5μm.

[0072] In some alternative embodiments, the drying temperature is 80°C to 110°C.

[0073] In these embodiments, drying at a temperature of 80°C to 110°C allows for the complete removal of moisture from the crystallization solution containing a regular octahedral solid phase, resulting in high-density 13X zeolite molecular sieve raw powder.

[0074] The drying temperature can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃ or 110℃.

[0075] It should be noted that the drying temperature can be between 90℃ and 100℃.

[0076] Based on a general inventive concept, embodiments of this application provide a 13X zeolite molecular sieve combining crystallization and molding processes. The 13X zeolite molecular sieve is obtained by the preparation method described in the first aspect, and the bulk density of the 13X zeolite molecular sieve is 0.72 g / cm³. 3 Up to 0.80 g / cm 3 The static water adsorption capacity of the 13X zeolite molecular sieve is ≥28%, and the specific surface area of ​​the 13X zeolite molecular sieve is ≥650 m². 2 / g.

[0077] The 13X zeolite molecular sieve is prepared based on the above preparation method. The specific steps of the preparation method can be referred to the above embodiments. Since the 13X zeolite molecular sieve adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0078] It should be noted that the bulk density is 0.72 g / cm³. 3 Up to 0.80 g / cm 3 Static water adsorption capacity ≥28% and specific surface area ≥650m² 2 The 13X zeolite molecular sieve with a density of / g demonstrates that the preparation method provided in the embodiments of this application can form 13X zeolite molecular sieves with high packing density, static water adsorption capacity, and specific surface area.

[0079] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0080] Example 1 like Figure 1 As shown in the embodiments of this application, a method for preparing 13X zeolite molecular sieve combining crystallization and molding processes is provided, including: S1. Mix the silicate solution and the aluminate solution to obtain a mixed gel; S2. Mix 13X zeolite molecular sieve seed crystals and mixed gel to obtain a gel mixture raw material; S3. The gel mixture is subjected to gradient crystallization to obtain a crystallized liquid with a regular octahedral solid phase; wherein, the gradient crystallization includes a first crystallization, a second crystallization and a third crystallization, and the temperature of the first crystallization is ≤ the temperature of the third crystallization is ≤ the temperature of the second crystallization; S4. The crystallization solution is washed, filtered and dried in sequence to obtain 13X zeolite molecular sieve powder.

[0081] The temperature for the first crystallization is 65℃; The temperature for the second crystallization is 8℃; The temperature for the third crystallization is 70℃.

[0082] The first crystallization time is 5 hours; The second crystallization time is 7 hours; The third crystallization time is 3 hours.

[0083] The silicate solution uses silicon dioxide as the first solid phase, and the aluminate solution uses aluminum oxide as the second solid phase. The amount of the first solid phase n1 and the amount of the second solid phase n2 satisfy the following: n1:n2=2.7:1.

[0084] The mass of the first solid phase is 25% of the mass of the silicate solution.

[0085] The mass m1 of the second solid phase and the volume V1 of the aluminate solution satisfy the following condition: m1:V1=60:1. If the unit of m1 is g, then V1 is L.

[0086] The particle size of the 13X zeolite molecular sieve seed crystals is 1.5 μm; The mass m2 of the 13X zeolite molecular sieve seed crystals and the mass m3 of the mixed gel satisfy the following condition: m2:m3=2.0:100.

[0087] The size of the octahedral solid phase in the crystallization solution of the regular octahedral solid phase is 3.5 μm to 4.5 μm.

[0088] The drying temperature is 90℃ to 100℃.

[0089] Example 2 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The temperature for the first crystallization is 67℃; The temperature for the second crystallization is 85℃; The temperature for the third crystallization is 75℃.

[0090] The first crystallization time is 6 hours; The second crystallization time is 7 hours; The third crystallization time is 3 hours.

[0091] The silicate solution uses silicon dioxide as the first solid phase, and the aluminate solution uses aluminum oxide as the second solid phase. The amount of the first solid phase n1 and the amount of the second solid phase n2 satisfy the following: n1:n2=2.85:1.

[0092] The mass of the first solid phase is 27% of the mass of the silicate solution.

[0093] The mass m1 of the second solid phase and the volume V1 of the aluminate solution satisfy the following condition: m1:V1=80:1. If the unit of m1 is g, then V1 is L.

[0094] The particle size of the 13X zeolite molecular sieve seed crystals is 1.7 μm.

[0095] Example 3 Compared to Example 1, the differences in this example are as follows, while the rest are the same: The temperature for the first crystallization is 67℃; The temperature for the second crystallization is 85℃; The temperature for the third crystallization is 75℃.

[0096] The first crystallization time is 6 hours; The second crystallization time is 7 hours; The third crystallization time is 3 hours.

[0097] The silicate solution uses silicon dioxide as the first solid phase, and the aluminate solution uses aluminum oxide as the second solid phase. The amount of the first solid phase n1 and the amount of the second solid phase n2 satisfy the following ratio: n1:n2=2.2:1.05.

[0098] The mass of the first solid phase is 28% of the mass of the silicate solution.

[0099] The mass m1 of the second solid phase and the volume V1 of the aluminate solution satisfy the following condition: m1:V1=70:1. If the unit of m1 is g, then V1 is L.

[0100] The particle size of the 13X zeolite molecular sieve seed crystals is 2 μm.

[0101] Comparative Example 1 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: Gradient crystallization is not performed; only a single-stage crystallization is used. The temperature of this single-stage crystallization is 80℃, and the crystallization time is 12h.

[0102] Comparative Example 2 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The particle size of the 13X zeolite molecular sieve seed crystals is 5 μm.

[0103] Comparative Example 3 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The mass m2 of the 13X zeolite molecular sieve seed crystals and the mass m3 of the mixed gel satisfy the following condition: m2:m3=1.0:100.

[0104] Comparative Example 4 Compared to Example 1, the differences in this comparative example are as follows, while the rest are the same: The mass m2 of the 13X zeolite molecular sieve seed crystals and the mass m3 of the mixed gel satisfy the following condition: m2:m3=3.5:100.

[0105] Relevant experimental and effect data: The performance of the 13X zeolite molecular sieve raw powder obtained from each embodiment and comparative example was tested, and the results are shown in Table 1.

[0106] Table 1 Performance test results of 13X zeolite molecular sieve raw powder

[0107] As shown in Table 1, the method for preparing 13X zeolite molecular sieves combining crystallization and molding processes provided in this application utilizes three mechanisms: a three-stage crystallization temperature gradient, a seed-directed induction mechanism, and a defect control process. Through the combined effect of these mechanisms, a significant increase in the packing density of the 13X zeolite molecular sieve is achieved. Compared to traditional preparation methods, this method provides reliable support for high packing density in terms of crystal size, morphology, and internal structure. The final packing density obtained by this method is 0.72 g / cm³. 3 Up to 0.80 g / cm 3 between.

[0108] Compared to Example 1, Comparative Example 1 only undergoes a single crystallization process, which makes it difficult for the gel-mixed raw materials to form a high-density 13X zeolite molecular sieve, and also affects the static water adsorption capacity, specific surface area, and crystal defect rate.

[0109] Compared to Example 1, Comparative Example 2 uses 13X zeolite molecular sieve seeds with a larger seed size. This results in poor orientation induction of the 13X zeolite molecular sieve seeds, leading to irregular morphology of the 13X zeolite molecular sieve crystals and increased packing gaps. Consequently, the packing density of the 13X zeolite molecular sieve powder is significantly lower than that of Example 1, and the defect rate of the 13X zeolite molecular sieve crystals is increased.

[0110] Compared to Example 1, Comparative Example 3 used fewer 13X zeolite molecular sieve seeds, resulting in insufficient orientation induction of the 13X zeolite molecular sieve and disordered crystal morphology. This reduced the packing density of the 13X zeolite molecular sieve raw material and significantly increased the defect rate of the 13X zeolite molecular sieve crystals. In contrast, Comparative Example 4 used more 13X zeolite molecular sieve seeds, leading to increased silicon content in the 13X zeolite molecular sieve nuclei. This resulted in smaller crystal sizes, increased interfacial space in the 13X zeolite molecular sieve powder, and a decrease in the packing density of the 13X zeolite molecular sieve powder, thus affecting its defect rate.

[0111] In summary, the embodiments of this application provide a method for preparing 13X zeolite molecular sieves that combines crystallization and molding processes. This method, through the synergistic effect of a three-stage crystallization temperature gradient innovation, a seed-directed induction mechanism, and a defect control process, constructs a high-density structural foundation from three core dimensions: crystal size and distribution, particle morphology, and internal structure, ultimately achieving a significant increase in the packing density of 13X zeolite molecular sieves.

[0112] Furthermore, this application provides a method for preparing 13X zeolite molecular sieve that combines crystallization and molding processes. This method can increase the bulk density of the 13X zeolite molecular sieve powder to 0.72 g / cm³. 3 Up to 0.80 g / cm 3 Meanwhile, the 13X zeolite molecular sieve raw powder prepared can also maintain excellent adsorption performance and structural stability.

[0113] Furthermore, this application provides a method for preparing 13X zeolite molecular sieve that combines crystallization and molding processes. The packing density of this method is 0.1 g / cm³ higher than that of conventional processes (e.g., the single-stage crystallization process in Comparative Example 1). 3 Up to 0.18 g / cm 3 The level, while the bulk density increases by 0.1 g / cm³. 3 The volume of the adsorption tower used can be reduced by 15% to 20%, which significantly reduces the investment cost of the equipment used in this preparation method.

[0114] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for preparing 13X zeolite molecular sieves by combining a crystallization process with a shaping process, characterized in that, The preparation method comprises: mixing a silicate solution and an aluminate solution to obtain a mixed gel; mixing 13X zeolite molecular sieve seeds and the mixed gel to obtain a gel mixed raw material; gradient crystallization of the gel mixed raw material to obtain a crystallization liquid with regular octahedral solid phases; wherein the gradient crystallization comprises first crystallization, second crystallization and third crystallization, and the temperature of the first crystallization ≤ the temperature of the third crystallization ≤ the temperature of the second crystallization; washing, filtering and drying the crystallization liquid in sequence to obtain 13X zeolite molecular sieve raw powder.

2. The production method according to claim 1, characterized by, The temperature of the first crystallization is 60-70°C; and / or The temperature of the second crystallization is 80-90°C; and / or The temperature of the third crystallization is 70-80°C.

3. The production method according to claim 1 or 2, characterized by, The time of the first crystallization is 4-6h; and / or The time of the second crystallization is 6-8h; and / or The time of the third crystallization is 2-3h.

4. The method of claim 1, wherein, The silicate solution takes silicon dioxide as a first solid phase, the aluminate solution takes aluminum oxide as a second solid phase, and the amount of substance n1 of the first solid phase and the amount of substance n2 of the second solid phase satisfy: n1:n2=(2-3):(0.9-1.1).

5. The preparation method according to claim 4, characterized in that, The mass of the first solid phase is 20-30% of the mass of the silicate solution.

6. The preparation method according to claim 4, characterized in that, The mass m1 of the second solid phase and the volume V1 of the aluminate solution satisfy: m1:V1=(50-80):1, if the unit of m1 is g, then V1 is L.

7. The preparation method according to claim 1, characterized in that, The particle size of the 13X zeolite molecular sieve seeds is 1-3μm; and / or The mass m2 of the 13X zeolite molecular sieve seeds and the mass m3 of the mixed gel satisfy: m2:m3=(1.5-2.5):

100.

8. The preparation method according to claim 1, characterized in that, The size of the octahedral solid phase in the crystallization liquid with regular octahedral solid phases is 3.5-4.5μm.

9. The method of claim 1, wherein, The temperature of the drying is 80-110°C.

10. A 13X zeolite molecular sieve combining a crystallization process with a shaping process, characterized in that, The 13X zeolite molecular sieve is obtained by the preparation method in any one of claims 1 to 9, the bulk density of the 13X zeolite molecular sieve is 0.72 g / cm 3 to 0.80 g / cm 3 , the static water adsorption amount of the 13X zeolite molecular sieve is ≥28%, and the specific surface area of the 13X zeolite molecular sieve is ≥650 m 2 / g.

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