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CN-122010136-A - X-type zeolite molecular sieve with low silicon-aluminum ratio, preparation method and application thereof

CN122010136ACN 122010136 ACN122010136 ACN 122010136ACN-122010136-A

Abstract

The invention provides a low silica to alumina ratio X-type zeolite molecular sieve, which comprises 70-90wt% of raw material X-type zeolite molecular sieve, 10-30wt% of trans-crystal X-type zeolite molecular sieve and not more than 1.5wt% of amorphous phase relative to the total weight of the raw material X-type zeolite molecular sieve, wherein the SiO 2 /Al 2 O 3 molar ratio of the low silica to alumina ratio X-type zeolite molecular sieve is 2.0-2.15, and the particle size distribution is in the range of 4-6 mu m and 400-600 nm. The invention also provides a method for preparing the X-type zeolite molecular sieve with low silicon-aluminum ratio and application thereof. The method has the advantages of easily available raw materials and simple steps, and the prepared zeolite molecular sieve has excellent adsorption performance.

Inventors

  • HU SHEN
  • XU QING
  • Lv Yaowu
  • HUANG SHANDONG
  • ZHANG KUISHAN

Assignees

  • 霍尼韦尔优欧辟工程技术研发有限公司

Dates

Publication Date
20260512
Application Date
20241108

Claims (14)

  1. 1. A low silica to alumina ratio X zeolite molecular sieve comprising, relative to its total weight, 70 to 90wt% of a starting X zeolite molecular sieve, 10 to 30wt% of a trans-crystallized X zeolite molecular sieve, and no more than 1.5wt% of an amorphous phase, said low silica to alumina ratio X zeolite molecular sieve having a SiO 2 /Al 2 O 3 molar ratio of 2.0 to 2.15 and a particle size distribution in the range of 4 to 6 μm and 400 to 600 nm.
  2. 2. The low silica to alumina ratio type X zeolite molecular sieve according to claim 1, comprising 80 to 90wt% of the starting material type X zeolite molecular sieve, 10 to 20wt% of the trans-crystallized type X zeolite molecular sieve, and no more than 1.0wt% of the amorphous phase.
  3. 3. The low silica to alumina ratio X zeolite molecular sieve according to claim 1 or 2, wherein the SiO 2 /Al 2 O 3 molar ratio is from 2.0 to 2.11.
  4. 4. A low silica to alumina ratio type X zeolite molecular sieve according to any one of claims 1 to 3, having a specific surface area of 720 to 870m 2 /g, a micropore area of 666 to 865m 2 /g and a micropore volume of 0.26 to 0.34cm 3 /g.
  5. 5. The low silica to alumina ratio type X zeolite molecular sieve according to any one of claims 1 to 4, wherein the specific surface area is 830 to 864m 2 /g, the micropore area is 750 to 855m 2 /g, and the micropore volume is 0.28 to 0.32cm 3 /g.
  6. 6. The low silica to alumina ratio type X zeolite molecular sieve according to any one of claims 1 to 5, wherein the starting material type X zeolite molecular sieve is selected from the group consisting of sodium type or sodium potassium type X zeolite having a SiO 2 /Al 2 O 3 molar ratio of 2.0 to 2.5 and a particle size in the range of 4 to 6 μm.
  7. 7. The low silica to alumina ratio type X zeolite molecular sieve according to any one of claims 1 to 6, wherein the trans-crystallized type X zeolite molecular sieve is obtained after in situ crystallization treatment with a binder selected from kaolin, montmorillonite, dickite, perlite, fire-resistant stone, halloysite or mixtures thereof, preferably halloysite.
  8. 8. A process for preparing the low silica to alumina ratio X zeolite molecular sieve according to any one of claims 1 to 7, comprising the steps of: 1) Uniformly mixing a raw material X-type zeolite molecular sieve with a binder, forming, drying and roasting; 2) Placing the formed molecular sieve after roasting in the step 1) into inorganic alkali solution to make in-situ crystallization treatment, and 3) Washing, drying and roasting the formed molecular sieve material after in-situ crystallization treatment.
  9. 9. The process according to claim 8, characterized in that in step 1) the raw material X-zeolite molecular sieve and the binder are mixed in a weight ratio of 70:30-90:10, preferably 80:20-90:10, the raw material X-zeolite molecular sieve and the binder being defined in claims 6 and 7, respectively.
  10. 10. The method according to claim 8 or 9, wherein in step 1), the drying temperature is 90-270 ℃, the drying time is 0.3-12h, the firing temperature is 300-650 ℃ and the firing time is 0.2-4h.
  11. 11. The method according to any one of claims 8-10, wherein in step 2) the inorganic base is selected from sodium hydroxide, potassium hydroxide or mixtures thereof, preferably the concentration of the inorganic base solution is 0.4-4mol/L, preferably 1-4mol/L, more preferably 3-4mol/L.
  12. 12. The method according to any one of claims 8 to 11, wherein in step 2), the in-situ crystallization treatment is performed at a liquid/solid ratio of inorganic alkali solution/shaped molecular sieve of 1 to 6L/kg, a treatment temperature of 80 to 100 ℃ and a treatment time of 2 to 24 hours.
  13. 13. The method according to any one of claims 8 to 12, wherein in step 3), the drying temperature is 120 to 250 ℃, the drying time is 0.4 to 3 hours, the firing temperature is 450 to 600 ℃ and the firing time is 0.2 to 2 hours.
  14. 14. Use of the low silica to alumina ratio X zeolite molecular sieve according to any one of claims 1 to 7 as a CO 2 adsorbent.

Description

X-type zeolite molecular sieve with low silicon-aluminum ratio, preparation method and application thereof Technical Field The present invention relates to the field of molecular sieve adsorbents. In particular to an X-type zeolite molecular sieve with low silicon-aluminum ratio, a preparation method and application thereof. Background The molecular sieve material is crystalline aluminosilicate, has ordered pore canal structure, good hydrothermal stability and adjustable functionality, and has wide application in the fields of industrial catalysis, adsorption separation, ion exchange and the like. The X-type zeolite is silicate crystal with FAU-type framework structure, the basic structure is SiO 4 and AlO 4 tetrahedron, and a three-dimensional network structure is formed by shared oxygen atoms, belonging to one of faujasites. The X-type zeolite molecular sieve can be further divided into a low-silicon X-type (SiO 2/Al2O3 =2.0-2.2), a medium-silicon X-type (SiO 2/Al2O3 =2.0-2.4) and a high-silicon X-type (SiO 2/Al2O3 =2.4-3.0) according to the molar ratio of SiO 2/Al2O3. The zeolite with low silicon-aluminum ratio contains a large amount of negative charges due to high aluminum crystal lattice, and has more balanced cations in the crystal lattice, so that the zeolite has higher adsorption capacity and selective adsorption performance, and therefore, the zeolite has very wide application prospect. There are reports on the current research on reducing the silica-alumina ratio of the X-type zeolite. Generally, the artificially synthesized X-type zeolite is in a powder form, and is required to be mixed with a binder, and the mixture is molded, activated and the like to obtain a molded molecular sieve with certain strength, which can be applied to industrial devices. In industrial application, the active ingredient of the molding material is molecular sieve, and the binder mainly plays a role in binding the molecular sieve, so that the molding molecular sieve is endowed with certain strength. The adhesive can endow the material with certain strength, reduce the effective composition of the molding material, and block partial pore canal to reduce the dynamic performance of the molecular sieve, so as to reduce the performance of the molding molecular sieve material in industrial application. Disclosure of Invention In view of the above problems of the prior art, the present invention provides a low silica to alumina ratio X-type zeolite molecular sieve having excellent micropore volume and adsorption capacity, simple preparation, low cost, and effective in solving or at least alleviating one or more of the problems of the prior art, a method for preparing the same, and applications thereof. Thus, according to one aspect of the present invention, there is provided a low silica to alumina ratio X zeolite molecular sieve comprising, relative to its total weight, 70 to 90wt% of a starting X zeolite molecular sieve, 10 to 30wt% of a trans-crystallized X zeolite molecular sieve and not more than 1.5wt% of an amorphous phase, said low silica to alumina ratio X zeolite molecular sieve having a SiO 2/Al2O3 molar ratio of 2.0 to 2.15 and a particle size distribution in the range of 4 to 6 μm and 400 to 600nm. According to another aspect of the present invention, there is provided a process for preparing the above-described low silica to alumina ratio type X zeolite molecular sieve comprising the steps of: 1) Uniformly mixing a raw material X-type zeolite molecular sieve with a binder, forming, drying and roasting; 2) Placing the formed molecular sieve after roasting in the step 1) into inorganic alkali solution to make in-situ crystallization treatment, and 3) Washing, drying and roasting the formed molecular sieve material after in-situ crystallization treatment. According to a further aspect of the present invention there is provided the use of a low silica to alumina ratio type X zeolite molecular sieve as described above as a CO 2 adsorbent. According to the invention, the raw material X-type zeolite molecular sieve is mixed with the binder, formed, dried and roasted, and then the inorganic alkali solution is adopted for in-situ crystallization treatment, so that the binder is converted into the molecular sieve, the finally obtained X-type zeolite molecular sieve has high crystallinity, low amorphous phase impurity (less than or equal to 1.5 wt%) and excellent micropore volume and CO 2 adsorption capacity, and meanwhile, the SiO 2/Al2O3 molar ratio of the X-type zeolite molecular sieve can be reduced to a theoretical value of 2.0, so that the X-type zeolite molecular sieve has a huge application prospect in the CO 2 adsorbent market. In addition, the raw materials for preparing the X-type zeolite molecular sieve with low silicon-aluminum ratio are easy to obtain, the preparation process is simple, and the X-type zeolite molecular sieve can be widely applied to industrial manufacturing processes. Drawings The present inv