A method for synthesizing MOR zeolite molecular sieve by crystal conversion using natural clinoptilolite as raw material

Abstract

The present invention provides a method for synthesizing MOR zeolite molecular sieve by converting natural clinoptilolite as raw material, which relates to the technical field of zeolite molecular sieves. In the present invention, natural clinoptilolite raw powder, alkali source, silicon source and water are mixed to obtain a synthesis mother liquor; the molar ratio of effective components in the synthesis mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10 - 32.5):1:(1.0 - 5.0):(210 - 500); the synthesis mother liquor is crystallized to obtain MOR zeolite molecular sieve. The present invention first prepares MOR-type zeolite with natural clinoptilolite as raw material, and omits the pretreatment steps of alkali fusion activation and ion exchange on the premise of ensuring the product purity and crystallinity. The process flow is simple, cost-saving, energy-consuming reduced and with high safety. The present invention realizes the resource utilization of natural clinoptilolite, the reduction of zeolite material cost and the synthesis of high-purity and high-crystallinity MOR-type zeolite at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of zeolite molecular sieves, and particularly to a method for synthesizing MOR zeolite molecular sieve by conversion of natural clinoptilolite as raw material. Background Art

[0002] Zeolite molecular sieve is a crystalline inorganic porous silicon-aluminate compound. Due to its regular and ordered pore structure, large specific surface area, and the modifiability of active sites on the framework, it is widely used in many fields such as adsorption separation, ion exchange, and petrochemical industry. Up to now, the Structure Commission of the International Zeolite Association (IZA) has included more than 256 different framework structure types of molecular sieves. As a good adsorption material, molecular sieves can be used as materials for drying, separation, and purification in industrial and environmental engineering. Secondly, by using the ion exchange performance of molecular sieves, purification treatment of industrial waste liquid and nuclear waste liquid, soil treatment, etc. can be carried out. In addition, molecular sieves have good shape selectivity and can be used as catalysts for many processes in the fields of petrochemical industry, coal chemical industry, etc., such as cracking, isomerization, heavy aromatics dealkylation, and methanol to olefins (MTO) reactions.

[0003] In China, the reserves of natural zeolite resources are very rich, especially natural clinoptilolite. Clinoptilolite deposits have been found in many provinces, municipalities, and autonomous regions across the country except Jinyun, Zhejiang. As a multifunctional, efficient, and inexpensive material, clinoptilolite has characteristics such as good thermal stability, short adsorption equilibrium time, low ion residue, wide acidity adaptation range, and recyclability, and has broad application prospects. However, due to the instability of the formation conditions of natural zeolite, defects are easily generated, which will lead to the disorder of some pores in natural zeolite, thereby affecting its adsorption and catalytic performance. If natural clinoptilolite is directly used in the catalytic field, the catalytic performance is poor, and the utilization efficiency of resources is relatively low, resulting in waste of resources. Therefore, it is of great practical significance to comprehensively utilize the cheap and easily available natural clinoptilolite resources to produce synthetic zeolites with more ordered pores, good performance, and greater application value. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for synthesizing MOR zeolite molecular sieve by conversion of natural clinoptilolite as raw material. The present invention uses natural clinoptilolite raw powder as raw material to synthesize high-value-added MOR zeolite molecular sieve products, and the synthesized zeolite molecular sieve has high purity and crystallinity.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for synthesizing MOR zeolite molecular sieve by conversion of natural clinoptilolite as raw material, comprising the following steps:

[0007] Mix natural clinoptilolite raw powder, an alkali source, a silicon source and water to obtain a synthetic mother liquor; the alkali source is an alkali metal hydroxide and / or an alkali metal oxide, and the amounts of the natural clinoptilolite raw powder, the alkali source, the silicon source and water are such that the molar ratio of the active ingredients in the synthetic mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10 - 32.5):1:(1.0 - 5.0):(210 - 500), where M represents an alkali metal;

[0008] Perform hydrothermal crystallization on the synthetic mother liquor to obtain MOR zeolite molecular sieve.

[0009] Preferably, the total mass content of SiO2 and Al2O3 in the natural clinoptilolite raw powder is greater than or equal to 90%.

[0010] Preferably, the alkali source includes one or more of sodium hydroxide, potassium hydroxide, sodium oxide and potassium oxide.

[0011] Preferably, the silicon source includes one or more of silica sol, sodium silicate and white carbon black.

[0012] Preferably, the method of mixing is as follows:

[0013] Perform first stirring and mixing on the alkali source and water to obtain an alkali solution;

[0014] After cooling the alkali solution to room temperature, perform second stirring and mixing with the natural clinoptilolite raw powder to obtain a suspension;

[0015] Perform third stirring and mixing on the suspension and the silicon source to obtain the synthetic mother liquor.

[0016] Preferably, the time of the second stirring and mixing is 2 - 5 h; the time of the third stirring and mixing is 20 - 60 min.

[0017] Preferably, the temperature of the crystallization is 150 - 200 °C and the time is 24 - 72 h.

[0018] Preferably, after the crystallization, it further includes successively filtering, washing the solid phase and drying the obtained reaction solution; the temperature of the drying is 50 - 100 °C and the time is 12 - 48 h.

[0019] The present invention provides a method for synthesizing MOR zeolite molecular sieve by converting natural clinoptilolite as raw material, comprising the following steps: mixing natural clinoptilolite raw powder, an alkali source, a silicon source and water to obtain a synthesis mother liquor; the alkali source is an alkali metal hydroxide, and the amounts of the natural clinoptilolite raw powder, the alkali source, the silicon source and water are such that the molar ratio of the active ingredients in the synthesis mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10 - 32.5):1:(1.0 - 5.0):(210 - 500), where M represents an alkali metal; subjecting the synthesis mother liquor to crystallization to obtain MOR zeolite molecular sieve. The present invention provides a new method for hydrothermally converting unactivated natural clinoptilolite raw powder into MOR zeolite with relatively high crystallinity. Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses natural clinoptilolite as a synthesis raw material, replacing pure chemical raw materials, which can effectively utilize the rich natural clinoptilolite ore resources, reduce the synthesis cost, produce MOR zeolite molecular sieve products with high added value, meet the requirements of green chemistry and sustainable development strategies, and open up a new way for the comprehensive utilization of natural minerals;

[0021] Compared with the process of synthesizing zeolite using most natural minerals as raw materials, which requires a pre-treatment step of ion exchange to remove Ca that inhibits the crystallization of zeolite molecular sieve, 2+ the present invention directly synthesizes zeolite molecular sieve using natural clinoptilolite raw powder, omitting the pre-treatment step of ion exchange to remove Ca, simplifying the steps of synthesizing zeolite from natural minerals, and saving time and raw material costs;

[0022] Compared with the solid-phase molten alkali method (mixing raw materials with alkali and roasting at 600°C) widely used for natural mineral or solid waste zeolitization, the present invention directly obtains MOR zeolite by one-step crystallization without pre-activation treatment, simplifies the steps of synthesizing zeolite from natural minerals, reduces the time cost, improves the safety, and avoids the large amount of energy consumption generated by the solid-phase molten alkali method;

[0023] The present invention can achieve relatively sufficient conversion of natural clinoptilolite, and the obtained MOR zeolite molecular sieve product has high purity and crystallinity. The XRD characterization shows a pure phase of MOR zeolite, and there is almost no un-converted HEU-type zeolite (natural clinoptilolite) phase. Description of the Drawings

[0024] Figure 1 XRD patterns of the zeolite molecular sieve products prepared in Examples 1 - 6 and Comparative Examples 1 - 2;

[0025] Figure 2 SEM electron micrographs of the MOR zeolite molecular sieve products prepared in Examples 1 - 6, Figure 2 in which (A1) - (A6) correspond to Examples 1 - 6 in sequence. Detailed implementation mode

[0026] The present invention provides a method for synthesizing MOR zeolite molecular sieve by converting natural clinoptilolite as raw material, which comprises the following steps:

[0027] Mix natural clinoptilolite raw powder, alkali source, silicon source and water to obtain a synthesis mother liquor; the alkali source is alkali metal hydroxide and / or alkali metal oxide, and the amounts of the natural clinoptilolite raw powder, alkali source, silicon source and water are such that the molar ratio of effective components in the synthesis mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10-32.5):1:(1.0-5.0):(210-500), where M represents alkali metal;

[0028] Perform hydrothermal crystallization on the synthesis mother liquor to obtain MOR zeolite molecular sieve.

[0029] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well-known to those skilled in the art.

[0030] The present invention mixes natural clinoptilolite raw powder, alkali source, silicon source and water to obtain a synthesis mother liquor. In the present invention, the component of the natural clinoptilolite raw powder is mainly HEU-type zeolite, containing a small amount of metal elements such as K and Ca; the total mass content of SiO2 and Al2O3 in the natural clinoptilolite raw powder is preferably greater than or equal to 90%. In the present invention, the alkali source is alkali metal hydroxide and / or alkali metal oxide, preferably including one or more of sodium hydroxide, potassium hydroxide, sodium oxide and potassium oxide. In the present invention, the silicon source preferably includes one or more of silica sol, sodium silicate and white carbon black. In the present invention, the amounts of the natural clinoptilolite raw powder, alkali source, silicon source and water are such that the molar ratio of effective components in the synthesis mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10-32.5):1:(1.0-5.0):(210-500), where M represents alkali metal. When calculating the molar ratio of effective components in the synthesis mother liquor, the silicon source is converted into SiO2, the alkali source is converted into M2O, and the natural clinoptilolite raw powder is converted into SiO2 and Al2O3.

[0031] In the present invention, the preferred method for mixing is:

[0032] Perform first stirring and mixing on the alkali source and water to obtain an alkali solution;

[0033] After cooling the alkali solution to room temperature, perform second stirring and mixing with natural clinoptilolite raw powder to obtain a suspension;

[0034] Perform third stirring and mixing on the suspension and the silicon source to obtain the synthesis mother liquor.

[0035] In the present invention, the time of the first stirring and mixing is based on the complete dissolution of the alkali source; the time of the second stirring and mixing is preferably 2 to 5 h, more preferably 3 h; the time of the third stirring and mixing is preferably 20 to 60 min, more preferably 30 min. In the present invention, the first stirring and mixing, the second stirring and mixing, and the third stirring and mixing are all preferably carried out at room temperature.

[0036] After obtaining the synthesis mother liquor, the present invention hydrothermally crystallizes the synthesis mother liquor to obtain MOR zeolite molecular sieve. In the present invention, the temperature of the hydrothermal crystallization is preferably 150 to 200 °C, more preferably 150 to 160 °C, and the time is preferably 24 to 72 h, more preferably 48 h. The present invention preferably transfers the synthesis mother liquor to a stainless steel autoclave with a polytetrafluoroethylene liner for the hydrothermal crystallization.

[0037] After the hydrothermal crystallization, the present invention preferably filters, solid-phase washes, and dries the obtained reaction solution in sequence to obtain MOR zeolite molecular sieve. In the present invention, the temperature of the drying is preferably 50 to 100 °C, more preferably 75 °C, and the time is preferably 12 to 48 h, more preferably 24 h.

[0038] Currently, some studies on synthesizing zeolite molecular sieves using natural minerals have been reported. However, in most processes for synthesizing zeolites from natural minerals, an alkali fusion activation step is required to treat the inert components therein in order to maximize the utilization of the silicon and aluminum species in the raw materials and improve the crystallinity of the product and the utilization rate of the raw materials. This activation method usually needs to be carried out at high temperature, and its high energy consumption and high risk limit the industrial application of alkali fusion activation. At the same time, the Ca element contained in many natural minerals will inhibit the crystallization process of zeolites in the zeolite synthesis system, which is not conducive to the synthesis process. In most cases, an ion exchange pretreatment step is required to remove Ca to reduce the crystallization time required and ensure the crystallinity of the product. However, this undoubtedly increases the complexity and cost of the synthesis process. In the present invention, since natural clinoptilolite mainly contains components such as HEU-type zeolite and is easily dissolved in the alkaline system, and a certain degree of decomposition can form the active units required for the crystallization of MOR-type molecular sieve, it can participate in the crystallization step after a short-time stirring in the alkaline synthesis system at room temperature. The present invention can directly obtain MOR zeolite molecular sieve by one-step crystallization without prior activation pretreatment. Compared with the solid-phase molten alkali method (mixing raw materials with alkali and calcining at 600 °C) widely used for natural mineral or solid waste zeolitization, the steps of synthesizing zeolites from natural minerals are simplified, the time cost is reduced, the safety is improved, and a large amount of energy consumption generated by the solid-phase molten alkali method is avoided. At the same time, because the content of Ca element in natural clinoptilolite is relatively small, only about 2%, and the synthesis ratio is mature, it is not easily affected by Ca 2+Therefore, the present invention directly synthesizes zeolite molecular sieves using natural clinoptilolite raw powder, which can omit the pretreatment step of removing Ca by ion exchange, further simplifies the steps of synthesizing zeolites from natural minerals, and saves time and raw material costs. The present invention realizes the first preparation of MOR-type zeolite using natural clinoptilolite as the raw material. On the premise of ensuring the product purity and crystallinity, the pretreatment steps of alkali fusion activation and ion exchange are omitted, achieving the purpose of simplifying the process flow, saving costs, reducing energy consumption, and improving safety.

[0039] The present invention also realizes the resource utilization of natural clinoptilolite, the reduction of the cost of zeolite materials, and the synthesis of high-purity and high-crystallinity MOR-type zeolites. The MOR-type molecular sieve, with the chemical formula 4Na2O·4A12O3·40SiO2·24H2O, was first synthesized by Barre et al. in 1952. The idealized MOR framework (space group: Cmcm) is constructed by mor(t-tes) as the building block (CBU). Each mor(t-tes) connects 4-membered rings in space, generating a two-dimensional (2D) channel system with 12-ring pore openings and 8-ring pore openings. The unit cell volume is The framework density is MOR molecular sieves have important applications in the catalytic field, such as methanol to olefins (MTO), dimethyl ether carbonylation, and adsorption. The present invention uses natural clinoptilolite as the synthesis raw material, replacing pure chemical raw materials, which can effectively utilize the rich natural clinoptilolite ore resources, reduce the synthesis cost, and produce high-value-added MOR zeolite molecular sieve products, meeting the requirements of green chemistry and sustainable development strategies, and opening up a new way for the comprehensive utilization of natural minerals.

[0040] To further illustrate the present invention, the following examples will be used to describe in detail the method for converting natural clinoptilolite into MOR zeolite molecular sieve provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0041] In each example, the composition of the raw material natural clinoptilolite: HEU-type zeolite, a small amount of metal elements such as K and Ca, and the total mass fraction of SiO2 + Al2O3 is more than 90%. The element content of natural clinoptilolite is determined by X-ray fluorescence spectroscopy and converted into the molar ratio of effective components in the synthesis mother liquor based on the mass content of SiO2 being 77.76% and the mass content of Al2O3 being 13.83%.

[0042] Example 1

[0043] The conversion of natural clinoptilolite into MOR zeolite molecular sieve is carried out as follows:

[0044] (1) Add 0.11 g of sodium hydroxide to 5.1 mL of water and stir until completely dissolved.

[0045] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0046] (3) Add 0.318 g of silica white to the suspension obtained in step (2), stir evenly at room temperature for 0.5 h to obtain a synthesis mother liquor, and the molar ratio of its active ingredients is 10SiO2:Al2O3:Na2O:210H2O.

[0047] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene lining, crystallize at 150 °C for 48 h; collect the crystallized product by filtration, washing and drying, the drying temperature is 75 °C and the drying time is 24 h to obtain product A1.

[0048] Perform XRD test on product A1, and the results are as Figure 1 (Curve A1) shown, which is consistent with the standard spectrum of MOR zeolite molecular sieve and is a pure phase.

[0049] Perform SEM electron microscopy test on product A1, and the results are as Figure 2 shown ( Figure 2 (A1) in), and it can be seen that the product has a crystal morphology.

[0050] Example 2

[0051] Use natural clinoptilolite as raw material to convert and synthesize MOR zeolite molecular sieve, and the steps are as follows:

[0052] (1) Add 0.18 g of potassium hydroxide to 7.8 mL of water and stir until completely dissolved.

[0053] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0054] (3) Add 5.6 g of silica sol (silicon dioxide mass content 30%) to the suspension obtained in step (2), stir evenly at room temperature for 0.5 h to obtain a synthesis mother liquor, and the molar ratio of its active ingredients is 32.5SiO2:Al2O3:K2O:500H2O.

[0055] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene lining, crystallize at 200 °C for 48 h; collect the crystallized product by filtration, washing and drying, the drying temperature is 75 °C and the drying time is 24 h to obtain product A2.

[0056] XRD test was carried out on product A2, and the results are as Figure 1 (Curve A2) shown, which is consistent with the standard spectrum of MOR zeolite molecular sieve and is a pure phase.

[0057] SEM electron microscopy test was carried out on product A2, and the results are as Figure 2 shown ( Figure 2 in (A2)), it can be seen that the product has a crystal morphology.

[0058] Example 3

[0059] Using natural clinoptilolite as raw material to transform and synthesize MOR zeolite molecular sieve, the steps are as follows:

[0060] (1) Add 0.42 g of sodium oxide to 11.0 mL of water and stir until evenly dissolved.

[0061] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0062] (3) Add 1.1 g of silica sol (silicon dioxide mass content 30%) to the suspension obtained in step (2), stir evenly at room temperature for 0.5 hour to obtain a synthesis mother liquor, and its effective component molar ratio is 10SiO2:Al2O3:5.0Na2O:500H2O.

[0063] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene lining, crystallize at 180 °C for 48 hours; collect the crystallized product by filtration, washing and drying methods, the drying temperature is 75 °C and the drying time is 24 hours to obtain product A3.

[0064] XRD test was carried out on product A3, and the results are as Figure 1 (Curve A3) shown, which is consistent with the standard spectrum of MOR zeolite molecular sieve and is a pure phase.

[0065] SEM electron microscopy test was carried out on product A3, and the results are as Figure 2 shown ( Figure 2 in (A3)), it can be seen that the substance has a crystal morphology.

[0066] Example 4

[0067] Using natural clinoptilolite as raw material to transform and synthesize MOR zeolite molecular sieve, the steps are as follows:

[0068] (1) Add 0.55 g of sodium hydroxide to 1.2 mL of water and stir until evenly dissolved.

[0069] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0070] (3) To the suspension obtained in step (2), add 5.6 g of silica sol (silica mass content 30%), stir evenly at room temperature for 0.5 hours to obtain a synthesis mother liquor, and the molar ratio of its active components is 32.5SiO2:Al2O3:5.0Na2O:210H2O.

[0071] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene lining, crystallize at 160 °C for 48 hours; collect the crystallized product by filtration, washing and drying methods, the drying temperature is 75 °C and the drying time is 24 hours to obtain product A4.

[0072] Perform XRD test on product A4, and the result is as Figure 1 (curve A4) shown, which is consistent with the standard pattern of MOR zeolite molecular sieve and is a pure phase.

[0073] Perform SEM test on product A4, and the result is as Figure 2 shown ( Figure 2 (A4) in it), it can be seen that the product has a crystal morphology.

[0074] Example 5

[0075] Use natural clinoptilolite as raw material to transform and synthesize MOR zeolite molecular sieve, and the steps are as follows:

[0076] (1) Add 0.11 g of sodium hydroxide to 5.1 mL of water and stir until evenly dissolved.

[0077] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0078] (3) To the suspension obtained in step (2), add 0.52 g of sodium silicate, stir evenly at room temperature for 0.5 hours to obtain a synthesis mother liquor, and the molar ratio of its active components is 10SiO2:Al2O3:1.0Na2O:210H2O.

[0079] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene lining, crystallize at 200 °C for 24 hours; collect the crystallized product by filtration, washing and drying methods, the drying temperature is 75 °C and the drying time is 24 hours to obtain product A5.

[0080] Perform XRD test on product A5, and the result is as Figure 1 (curve A5) shown, which is consistent with the standard pattern of MOR zeolite molecular sieve and is a pure phase.

[0081] Perform SEM test on product A5, and the result is as Figure 2As shown Figure 2 in (A5)), it can be seen that the product has a crystalline morphology.

[0082] Example 6

[0083] Using natural clinoptilolite as raw material, MOR zeolite molecular sieve was synthesized by conversion crystallization, and the steps are as follows:

[0084] (1) Add 1.68 g of sodium oxide to 44.0 mL of water and stir until uniformly dissolved.

[0085] (2) After the above solution is cooled to room temperature, add 4.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0086] (3) Add 4.4 g of silica sol (silica mass content 30%) to the suspension obtained in step (2), stir evenly at room temperature for 0.5 h to obtain a synthesis mother liquor, and its effective component molar ratio is 10SiO2:Al2O3:5.0Na2O:500H2O.

[0087] (4) Transfer the synthesis mother liquor obtained in step (3) to a stainless steel autoclave with a polytetrafluoroethylene liner, crystallize at 180 °C for 48 h; collect the crystallized product by filtration, washing and drying methods, and the drying temperature is 75 °C and the drying time is 24 h to obtain product A6.

[0088] Perform XRD test on product A6, and the results are as Figure 1 (Curve A6) shown, which is consistent with the standard pattern of MOR zeolite molecular sieve and is a pure phase.

[0089] Perform SEM electron microscopy test on product A6, and the results are as Figure 2 shown Figure 2 in (A6)), it can be seen that the product has a crystalline morphology.

[0090] Comparative Example 1 (Synthesis ratio of MOR-type zeolite given by the International Zeolite Association, using natural clinoptilolite powder as the aluminum source)

[0091] (1) Add 0.78 g of sodium hydroxide to 18.9 mL of water and stir until uniformly dissolved.

[0092] (2) After the above solution is cooled to room temperature, add 1.0 g of natural clinoptilolite raw powder and stir for 3 h.

[0093] (3) Add 2.94 g of sodium silicate to the suspension obtained in step (2), stir evenly at room temperature for 0.5 h to obtain a synthesis mother liquor, and its effective component molar ratio is 30SiO2:Al2O3:6Na2O:780H2O.

[0094] (4) Transfer the synthetic mother liquor obtained in step (3) to a stainless-steel reactor with a polytetrafluoroethylene lining, and crystallize at 170 °C for 24 hours; collect the crystallized product by filtration, washing, and drying. The pH of the product after washing is 9, the drying temperature is 75 °C, and the drying time is 24 hours to obtain product B1.

[0095] Perform XRD testing on product B1, and the results are as Figure 1 (Curve B1) shown. The product is a mixed phase of MOR and MFI zeolites with poor purity.

[0096] Comparative Example 2 (Synthesis of MOR zeolite using aluminum hydroxide instead of natural clinoptilolite)

[0097] (1) Add 0.18 g of potassium hydroxide to 7.8 mL of water and stir until completely dissolved.

[0098] (2) After the above solution is cooled to room temperature, add 0.211 g of aluminum hydroxide and stir for 3 h.

[0099] (3) Add 5.6 g of silica sol to the suspension obtained in step (2), stir evenly at room temperature for 0.5 hour to obtain a synthetic mother liquor, and the molar ratio of its active components is 32.5SiO2:Al2O3:1.0K2O:500H2O.

[0100] (4) Transfer the synthetic mother liquor obtained in step (3) to a stainless-steel reactor with a polytetrafluoroethylene lining, and crystallize at 200 °C for 48 hours; collect the crystallized product by filtration, washing, and drying. The drying temperature is 75 °C and the drying time is 24 hours to obtain product B2.

[0101] Perform XRD testing on product B2, and the results are as Figure 1 (Curve B2), which is consistent with the standard pattern of MOR zeolite, is a pure phase, but the crystallinity is poor.

[0102] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for synthesizing MOR zeolite molecular sieve by conversion of natural clinoptilolite as raw material, which is characterized in that, Comprising the following steps: Mixing natural clinoptilolite raw powder, an alkali source, a silicon source, and water to obtain a synthetic mother liquor; the alkali source is an alkali metal hydroxide and / or an alkali metal oxide, and the amounts of the natural clinoptilolite raw powder, the alkali source, the silicon source, and water are such that the molar ratio of the active ingredients in the synthetic mother liquor satisfies: SiO2:Al2O3:M2O:H2O = (10 - 32.5):1:(1.0 - 5.0):(210 - 500), where M represents an alkali metal; Subjecting the synthetic mother liquor to hydrothermal crystallization to obtain a MOR zeolite molecular sieve.

2. The method according to claim 1, characterized in that, The total mass content of SiO2 and Al2O3 in the natural clinoptilolite raw powder is greater than or equal to 90%.

3. The method according to claim 1, characterized in that The alkali source includes one or more of sodium hydroxide, potassium hydroxide, sodium oxide, and potassium oxide.

4. The method according to claim 1, wherein The silicon source includes one or more of silica sol, sodium silicate, and fumed silica.

5. The method according to any one of claims 1 to 4, characterized in that The method of mixing is as follows: First stirring and mixing the alkali source and water to obtain an alkali solution; After cooling the alkali solution to room temperature, second stirring and mixing it with the natural clinoptilolite raw powder; Obtaining a suspension; Third stirring and mixing the suspension with the silicon source to obtain the synthetic mother liquor.

6. The method according to claim 5, wherein The time for the second stirring and mixing is 2 - 5 h; the time for the third stirring and mixing is 20 - 60 min.

7. The method according to claim 1, characterized in that, The temperature of the hydrothermal crystallization is 150 - 200 °C, and the time is 24 - 72 h.

8. The method according to claim 1 or 7, characterized in that After the hydrothermal crystallization, it further includes successively filtering, solid-phase washing, and drying the obtained reaction solution; the drying temperature is 50 - 100 °C, and the time is 12 - 48 h.

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