Preparation method of mesoporous Y-type molecular sieve

Abstract

The invention discloses a preparation method of a Y-type molecular sieve containing mesopores, which comprises the following steps: uniformly mixing a silicon source, a guiding agent and silica-alumina gel, sequentially adding an aluminum source and a sodium metaaluminate solution to form gel, and crystallizing and post-treating to obtain the Y-type molecular sieve, the guiding agent is obtained by mixing and aging a sodium metaaluminate solution, silicon powder, a silicon source and an alkaline compound; the silica-alumina gel is obtained by performing activation and acid treatment on natural minerals, mixing the natural minerals with NaY mother liquor, and performing aging; the same sodium metaaluminate solution is adopted when the gel is formed and the guiding agent is prepared, the sodium metaaluminate solution contains a stabilizer, and the molar ratio of Na2O to Al2O3 to SiO2 in the gel is (1.0-1.9): 1: (5-7). The Y-type molecular sieve synthesis method provided by the invention can form mesopores without a structural auxiliary agent or a template agent, and has the outstanding advantages of low cost, simple process flow, high quality of the synthesized Y-type molecular sieve and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve synthesis, and in particular relates to a method for preparing a mesoporous Y-type molecular sieve. Background Art

[0002] Y-type zeolite (also known as Y-type molecular sieve) is widely used in the petroleum refining industry due to its developed three-dimensional pores and adjustable acidity. Crystallinity and silicon-aluminum ratio (SiO2 / Al2O3) are one of the most important factors affecting the properties and functions of Y-type zeolite. Currently, most mature Y-type molecular sieve production methods use a directing agent method similar to that proposed by Grace Company in US3639099 and US3671191. This method can synthesize Y-type molecular sieve products with a crystallinity of more than 83% and a silicon-aluminum ratio of about 5.0 within 28 hours.

[0003] In order to improve the reaction performance of Y-type molecular sieve, most of the improvements are made from improving the pore structure of Y-type molecular sieve. The methods for improving the pore structure of Y-type molecular sieve can be roughly divided into pore formation during the synthesis process and post-modification pore formation. The pore formation during the synthesis process generally adds different substances and templates to form mesopores during the synthesis process. The post-modification pore formation is generally carried out by chemical methods, hydrothermal superstabilization, hydrothermal superstabilization-acid treatment and other methods. At present, the hydrothermal superstabilization method is mostly used in industry. Through hydrothermal superstabilization, part of the skeleton aluminum of the molecular sieve is removed, and Al in Si-O-Al is replaced by Si, which reduces the acid center density of the active component Y-type molecular sieve and increases the acid strength. More importantly, through the hydrothermal superstabilization modification process, the molecular sieve has more abundant secondary pores, and the presence of secondary pores improves the mass transfer and diffusion of macromolecular reactants and the accessibility of active centers on the inner pore surface, thereby bringing better reaction results. However, the framework of the zeolite will be significantly damaged after hydrothermal superstabilization, and the large amount of non-framework aluminum formed will block the pores, making it easier to form carbon deposits on the catalyst surface, which is not conducive to the reaction. Therefore, many researchers use acid dealumination to control the acidity of the catalyst and clean the catalyst pores.

[0004] Grace Company uses an inorganic template method to add cesium ions and a conventionally prepared directing agent to the reactant gel to synthesize octahedral molecular sieves CSZ-1, CSZ-3, etc., hoping to improve the molecular sieve pore structure (USP4333859, USP4309313), but the cesium ions in the product obtained by this method are not easy to remove and need to be exchanged and roasted multiple times. Organic templates are usually removed by high-temperature roasting and cannot be recycled, which increases the synthesis cost and brings environmental burden. In addition, the crystallization time required for the template method to synthesize Y-type molecular sieves is long, and the secondary use of the template is still a difficult problem. The so-called template-free direct synthesis method refers to the preparation of directing agents, gels, and crystallization. No template is added in any preparation process, but by adjusting the conditions of the preparation system, adding different functional components, etc., so as to achieve the purpose of improving the mesopores of the product. Therefore, manufacturing mesopores from the synthesis process has become a very important method for improving the pore structure of Y-type molecular sieves.

[0005] For example, in Chinese patent document CN109665539B, the generated Y-type molecular sieve is re-pulped, then mixed with a silane coupling agent and a quaternary ammonium salt surfactant and reacted at a temperature of 60 to 200°C and autogenous pressure for 4 to 48 hours to obtain a NaY molecular sieve, which is to volatilize organic matter to create a certain mesopore, but under this condition, the synthesis will produce a large amount of organic matter released, affecting the environment. Chinese patent document CN104891523A also discloses a preparation method for preparing a mesoporous Y-type molecular sieve using a template agent, and Chinese patent document CN101468801 discloses the use of modified bentonite for activation and modification, and then replaces a part of the silicon and aluminum sources to prepare the Y-type molecular sieve, and the mesopore volume of the obtained Y-type molecular sieve is 0.10-0.40 ml / g; the method uses modified bentonite as a part of the silicon and aluminum sources. Chinese patent document CN114426286A discloses a method for repeatedly hydrothermally crystallizing to obtain a mesoporous Y-type molecular sieve. Chinese patent document CN114956117A discloses a method for synthesizing mesoporous molecular sieves by supplementing a template agent in a mother liquor. Chinese patent document CN113149028A discloses a method for preparing NaY molecular sieves using active silicon powder and recycling the mother liquor, comprising the following steps: S1. Preparation of active silicon powder: Select one or more of waste FCC catalyst, bentonite, kaolin, and fly ash, add hydrochloric acid or sulfuric acid at 1.0-1.5 times the theoretical acid consumption, stir and acid-lyze for 1-6 hours, filter and separate, and use the solution for preparation of finished products such as polyaluminum; after washing the solid, it is active silicon slag, which is dried and crushed to obtain active silicon powder; S2. Preparation of NaY molecular sieve crystallization directing agent; S 3. Colloidation: Mix active silicon powder, low-alkali sodium aluminate and directing agent in a certain proportion, stir evenly at 10-80°C for 0.5-5 hours, then add a calculated amount of water to make the total molar ratio of the mixed solution Na2O: Al2O3: SiO2: H2O = 2-6: 1: 8-15: 90-350, and stir at 10-60°C for 0.5-5 hours; S4. Crystallization: Crystallize the mixture at 80-120°C in a reactor for 6-48h, and then filter, wash and dry to obtain the product NaY, and collect the mother liquor after filtration. This method uses the silicon powder obtained after treatment as a silicon source, but there are problems such as complex preparation process and difficulty in filtration, and the quality of the Y-type molecular sieve obtained by this synthesis method is lower than that of the conventional gel method, and there are impurity crystals, which is not suitable for continuous industrial processes.

[0006] Chinese patent documents CN101767799A, CN1621348A, CN1621349A, and CN101254929A all disclose methods for preparing NaY molecular sieves by two or more stages of crystallization. However, the above-mentioned methods for preparing NaY molecular sieves mainly involve how to improve the silicon-aluminum ratio, and there is no mention of preparing mesoporous NaY molecular sieves by synthesis. Chinese patent document CN110862096A uses a guiding gel after water glass dispersion treatment to synthesize NaY. The prepared NaY molecular sieve has a high silicon-aluminum ratio, good hydrothermal stability, large pore size, and high specific surface area. However, this method requires the preparation of a guiding gel first, and the process flow is long and complicated.

[0007] In addition, there are also mesoporous structures achieved by post-modification methods. For example, Chinese patent document CN110862097A discloses that the pore volume of Y-type molecular sieve is increased to 0.40mL / g or more by combining multiple hydrothermal ultra-stabilization, roasting and acid treatment, but there are problems such as cumbersome steps and high cost. CN111099615B discloses that a mesoporous molecular sieve is obtained under certain conditions after full contact between Y molecular sieve and an ordered mesoporous directing agent. CN110540213A discloses that a Y molecular sieve rich in mesopores on the surface is obtained by repeated ammonium exchange and other methods. CN114713271A discloses that at least one of methylamine, ethylamine, ethylenediamine, 1-propylamine, and isopropylamine is mixed with a Y-type molecular sieve to prepare mesopores. CN107973313B discloses that a mesoporous Y-type molecular sieve is obtained by multiple treatments with organic acid, sodium hydroxide, and ammonium nitrate. CN106927481A and CN106927477A both report a method of mixing a Y-type molecular sieve with glycerol, and then treating it with an inorganic directing agent, a quaternary ammonium compound, ethanol and cellulose at a certain temperature and time to obtain a Y-type molecular sieve containing mesopores. CN110871102A discloses a composite structure molecular sieve obtained by in-situ growth of aluminum oxide on a Y-type molecular sieve, CN115594193A discloses a method of simultaneously performing dealumination, mesopore formation and unit cell shrinkage in an oxygen-free environment by treating it with high-temperature acid steam to obtain a mesoporous Y-type molecular sieve, and CN107777697B discloses a method of preparing a Y-type molecular sieve containing mesopores by alkali treatment. CN101108736 discloses a method of forming mesopores by combining dilute acid treatment with silicon source recrystallization, CN104760973A discloses a method of preparing Y-type molecular sieve with ultra-high mesopore content by utilizing gas phase ultra-stable method, CN114477217A discloses post-modification by treating with ammonium fluorosilicate or hydrofluoric acid, CN111086999A and CN106672997B report a method of forming pores by high temperature and high pressure modification, and CN109775716A, CN112661166B, and CN112850742A respectively disclose a method of obtaining mesopores by treating with organic bases and mixing multiple template solutions and then calcining.

[0008] In summary, the formation of multi-level pores or mesopores in the synthesis stage of Y-type molecular sieves is mainly achieved by introducing organic or inorganic templates and structural additives, which has the problems of high cost, inconvenience in implementation, environmental problems caused by the removal of templates, and difficulty in industrial continuous implementation. The subsequent modification to form mesopores mainly focuses on acid-base pretreatment, chemical dealumination such as ammonium fluorosilicate dealumination and gas-phase ultra-stable dealumination, which has the prominent problems of complex process flow and severe degree of crystallinity destruction. Summary of the invention

[0009] Based on the problems existing in the prior art and the directions for improvement, the present invention provides a method for preparing a Y-type molecular sieve containing mesopores. Compared with the existing synthesis method of a Y-type molecular sieve that forms multi-level pores or mesopores in the synthesis stage, the Y-type molecular sieve synthesis method provided by the present invention can form mesopores without the need for structural additives or templates, and has outstanding advantages such as low cost, simple process flow, and high quality of synthesized Y-type molecular sieves.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A method for preparing a mesoporous Y-type molecular sieve comprises the following steps:

[0012] After the silicon source, the directing agent and the silica-alumina gel are uniformly mixed, the aluminum source and the sodium metaaluminate solution are added in sequence to form a gel, and after crystallization and post-treatment, a Y-type molecular sieve is obtained;

[0013] The guiding agent is obtained by mixing and aging sodium aluminate solution, silicon powder, water glass and alkaline compounds;

[0014] The silica-alumina gel is obtained by activating and acid-treating natural minerals and mixing with NaY mother liquor for aging;

[0015] The sodium aluminate solution used in forming the gel and preparing the guiding agent is the same, the sodium aluminate solution contains a stabilizer, and the concentration of Al2O3 is 190-400g / L, and the concentration of Na2O is 210-400g / L; the molar ratio of Na2O to Al2O3 is controlled to be 0.86-3.46:1.

[0016] The molar ratio of Na2O, Al2O3 and SiO2 in the gel is (1.0-1.9):1:(5-7).

[0017] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, during the preparation of the silica-alumina gel, the acid treatment is to treat the activated natural mineral with an acid solution at a pH of 2.8 to 6.0 and 20 to 100° C. for 10 to 90 minutes;

[0018] The concentration of the acid solution is 0.1 to 15 mol / L.

[0019] The liquid-to-solid ratio of the activated natural mineral to the acid solution is 4-15.

[0020] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, during the preparation of the silica-alumina gel, the activation temperature is 600-900° C. and the activation time is 20-100 min.

[0021] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, during the preparation of the silica-alumina gel, the aging temperature is 20 to 100° C. and the time is 10 to 240 min.

[0022] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the SiO2 concentration in the NaY mother liquor is 40 to 65 g / L, and the Na2O concentration is 20 to 40 g / L;

[0023] The quality data of the silica-alumina gel are: SiO2 50%-65%, Al2O3 15%-20%, Na2O 12%-15%, solid content 10%-50%, and density 1.0-1.4.

[0024] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the natural mineral is selected from one or more of soft and hard kaolinite, coal-based kaolinite, halloysite, attapulgite, sepiolite and palygorskite;

[0025] The acid solution is selected from an inorganic acid solution or an organic acid solution, the inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, and the organic acid is selected from one or more of formic acid, citric acid, oxalic acid, and acetic acid.

[0026] Optionally, in the preparation method of the mesoporous Y-type molecular sieve provided by the present invention, the sodium aluminate solution is obtained by stirring a 25wt% to 50wt% sodium hydroxide solution and an aluminum hydroxide powder with an Al2O3 content of not less than 60wt% at 0.1 to 0.4MPa and 100 to 140°C for 2 to 6 hours, and then adding a stabilizer.

[0027] Optionally, in the preparation of the sodium aluminate solution provided by the present invention, the stabilizer is selected from one or more of sodium carbonate, sodium bicarbonate, and ammonia water;

[0028] Based on the total mass of the sodium hydroxide solution and the aluminum hydroxide powder being 100%, the added mass of the stabilizer is 1% to 10%.

[0029] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the molar ratio of Na2O, Al2O3 and SiO2 in the directing agent is (10-20):1:(10-20).

[0030] Optionally, in the preparation method of the mesoporous Y-type molecular sieve provided by the present invention, the preparation of the directing agent includes the following steps: adding the alkaline compound and the silicon powder to the sodium aluminate solution, adding the silicon source after mixing evenly, and aging at 30-40°C for 6-24 hours.

[0031] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, during the preparation of the directing agent, the alkaline compound is selected from any one of sodium hydroxide, sodium carbonate and sodium bicarbonate;

[0032] The mass ratio of the alkaline compound to the directing agent is 0.01 to 0.1 based on Al2O3;

[0033] Calculated in terms of SiO2, the molar ratio of the silicon powder to the directing agent is 0.01 to 0.2.

[0034] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, based on the mass of the gel as 100%, the content of the directing agent is 1wt% to 30wt%, preferably 1wt% to 20wt%.

[0035] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the post-treatment includes the steps of separation, washing and drying; the washing step is carried out with deionized water until the pH value of the filtrate is 10.0-10.5.

[0036] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the crystallization is hydrothermal crystallization, and the temperature of the hydrothermal crystallization is 90 to 100° C. and the time is 16 to 40 hours.

[0037] Optionally, in the method for preparing the mesoporous Y-type molecular sieve provided by the present invention, the silicon source is selected from one or more of silica alumina powder, silica sol, water glass, white carbon black and sodium silicate; the SiO2 concentration in the water glass is 260-350 g / L and the modulus is 2.96-3.40.

[0038] The aluminum source is selected from one or more of aluminum sulfate, aluminum phosphate, aluminum chloride, aluminum nitrate, aluminum fluoride, aluminum formate and aluminum acetate.

[0039] Optionally, the method for preparing the mesoporous Y-type molecular sieve provided by the present invention comprises the following steps:

[0040] Slowly add the directing agent and silica-alumina gel to the silicon source in sequence, mix evenly (such as stirring and mixing for 30min to 60min), then add the aluminum source and mix thoroughly (such as mixing for 30min to 60min), and finally add the sodium aluminate solution to form a gel, and obtain the Y-type molecular sieve through crystallization, filtration, washing and drying.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Beneficial effect 1: The preparation method of the mesoporous Y-type molecular sieve provided by the present invention overcomes the problem of poor stability of the main raw material sodium aluminate solution through the mutual coordination between the various raw material steps. Combined with the low-sodium gel formula, compared with the conventional formula, it can achieve the goal of reducing the total synthesis cost by 30% to 50% and reducing salt emissions by 40% to 50%.

[0043] Beneficial effect 2: The preparation method of the mesoporous Y-type molecular sieve provided by the present invention changes the idea of ​​adding an organic template or an inorganic compound to the traditional Y-type molecular sieve. The modified natural minerals are not only used to provide a silicon and aluminum source, but also are aged with the crystallization mother liquor to prepare molecular sieve precursors and structural units. The high-quality Y-type molecular sieve (silicon-aluminum ratio of 5.2 or more, crystallinity of 90% to 99%, and total pore volume of 0.4 to 0.5 mL / g) is synthesized by combining hydrothermal crystallization, and is successfully applied in industry.

[0044] Specifically, 1) In the prior art, in order to realize the pore formation of Y-type molecular sieve, most of them adopt the post-modification method, that is, first synthesize the Y-type molecular sieve, and then modify and form the pores. Not only is the process long, but also the processing cost is high. The present invention combines the product rich in activated alumina after natural mineral activation and acid treatment with the NaY mother liquor to form a silica-alumina gel with a multi-level pore distribution, strengthens the silica-alumina mass transfer and combined growth during the synthesis process, not only improves the pore structure of the Y-type molecular sieve in situ, but also increases the molecular sieve precursor and structural unit after aging with the crystallized mother liquor, and the utilization rate of the NaY mother liquor is also improved, effectively saving process steps and reducing costs. 2) In the traditional Y-type molecular sieve synthesis process, different concentrations of sodium aluminate solutions are used in the directing agent configuration process and the gel preparation process, respectively, which increases the complexity of the process operation, energy consumption and various raw material consumption. The present invention uses only one concentration of sodium aluminate solution when preparing the directing agent and the gel, which reduces the introduction of sodium and the type of synthetic solution from the source, thereby reducing the sodium, sulfate and other ions that may form salts brought in by the synthesis, and greatly reduces the energy consumption of the production enterprise, the consumption and transportation of various raw materials while reducing the types of synthetic solutions and the sodium oxide brought in by the synthesis, and significantly reduces the synthesis cost. 3) Sodium aluminate solution is a very important aluminum source in the synthesis of Y-type molecular sieves. Under normal conditions, the preparation of the solution strictly controls the temperature, and the concentration control of the sodium oxide and aluminum oxide ratio in the solution is very strict. In addition, the stability of the sodium aluminate solution is poor, and the general storage time cannot exceed 72 hours, which greatly limits the efficiency of the synthesis and causes energy consumption and waste of raw materials. Sodium aluminate exists in the form of Na[Al(OH)4] (sodium tetrahydroxyaluminate) in the aqueous solution, is in an unstable state, and is easily precipitated in the form of Al(OH)3, causing the sodium aluminate solution to decompose and deteriorate. The present invention starts from the root cause of the poor stability of sodium aluminate solution, adds a stabilizer, and the stabilizer dissociates into OH in the solution. - Preventing the decomposition of Na[Al(OH)4], thereby achieving the purpose of stabilizing the sodium aluminate solution, making the obtained sodium aluminate solution more stable and convenient for storage and transportation, reducing raw material and production costs, and reducing the amount of wastewater and waste residue generated. 4) The present invention adds silicon powder to the directing agent, which not only plays the role of supplementing the silicon source, but more importantly, after the silicon powder is added, countless "silicon islands" are formed. During the aging stage of the directing agent, aluminum ions are more easily adsorbed on the silicon islands to form the initial structural units of silicon and aluminum, thereby increasing the crystal nucleus, promoting crystal growth, and increasing the relative crystallinity of the molecular sieve. 5) On the basis of the above three raw materials, a gel ratio with lower sodium is adopted, the utilization rate of the silicon and aluminum source is high, the crystallization time is short, the entire process operation is simple and efficient, and the obtained Y-type molecular sieve has high crystallinity and a developed pore structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the XRD diagram of the Y-type molecular sieve prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0047] If no specific experimental steps or conditions are specified in the examples and comparative examples, the conventional experimental steps or conditions described in the literature in the art can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0048] Source of raw materials or equipment: (including raw material name, specifications, manufacturer, etc.)

[0049] Sodium silicate: industrial product, sourced from the Catalyst Division of Lanzhou Petrochemical Company (SiO2: 19.60%, Na2O: 6.86%)

[0050] Sodium aluminate: industrial product, sourced from the catalyst division of Lanzhou Petrochemical Company (Na2O: 12.10%, Al2O3: 8.06%)

[0051] Aluminum sulfate: industrial product, sourced from the Catalyst Division of Lanzhou Petrochemical Company (Al2O3: 7.10%)

[0052] Sodium hydroxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum phosphate, aluminum nitrate, aluminum acetate, aluminum formate, aluminum fluoride, sodium carbonate, sodium bicarbonate, silica sol, soft kaolin, hard kaolin, coal-based kaolin, halloysite, attapulgite, sepiolite, palygorskite, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, citric acid, oxalic acid, acetic acid: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0053] Silica fume: chemically pure, Qingdao Jinyang Fine Chemical Co., Ltd.

[0054] Preparation of sodium aluminate solution

[0055] Sodium aluminate solution 1: 25wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 60wt% were reacted in an autoclave at 0.4MPa and 140℃ for 6 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:0.86. The Al2O3 concentration in the sodium aluminate solution was 400g / L, and the Na2O concentration was 210g / L. Then, solid sodium hydroxide accounting for 1% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0056] Sodium aluminate solution 2: 50wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 80wt% were reacted in an autoclave at 0.1MPa and 100℃ for 2 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:3.46. The Al2O3 concentration in the sodium aluminate solution was 190g / L, and the Na2O concentration was 400g / L. Then, solid sodium bicarbonate accounting for 5% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0057] Sodium aluminate solution 3: 40wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 90wt% were reacted in an autoclave at 0.3MPa and 100℃ for 2 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.08. The Al2O3 concentration in the sodium aluminate solution was 380g / L, and the Na2O concentration was 250g / L. Then, solid sodium carbonate accounting for 10% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0058] Sodium aluminate solution 4: 30wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 95wt% were reacted in an autoclave at 0.2MPa and 100℃ for 4 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:84. The Al2O3 concentration in the sodium aluminate solution was 250g / L, and the Na2O concentration was 280g / L. Then, an ammonia solution (mass concentration of 20%) accounting for 8% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for standby use.

[0059] Sodium aluminate solution 5: 35wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 95wt% were reacted in an autoclave at 0.1MPa and 120℃ for 5 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:2.08. The Al2O3 concentration in the sodium aluminate solution was 210g / L, and the Na2O concentration was 265g / L. Then, an ammonia solution (mass concentration of 20%) accounting for 7% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0060] Sodium aluminate solution 6: 45wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 60wt% were reacted in an autoclave at 0.4MPa and 140℃ for 2 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.65. The Al2O3 concentration in the sodium aluminate solution was 300g / L, and the Na2O concentration was 300g / L. Then, solid sodium hydroxide accounting for 3% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0061] Sodium aluminate solution 7: 33wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 70wt% were reacted in an autoclave at 0.3MPa and 130℃ for 3 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.88. The Al2O3 concentration in the sodium aluminate solution was 280g / L, and the Na2O concentration was 320g / L. Then, solid sodium bicarbonate accounting for 2% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and set aside.

[0062] Sodium aluminate solution 8: 37wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 77wt% were reacted in an autoclave at 0.2MPa and 110℃ for 5 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.72. The Al2O3 concentration in the sodium aluminate solution was 330g / L, and the Na2O concentration was 345g / L. Then, solid sodium carbonate accounting for 4% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and set aside.

[0063] Sodium aluminate solution 9: 32wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 73wt% were reacted in an autoclave at 0.1MPa and 135°C for 5 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.79. The Al2O3 concentration in the sodium aluminate solution was 350g / L, and the Na2O concentration was 380g / L. Then, an ammonia solution (mass concentration 20%) accounting for 6% of the total mass of the sodium aluminate solution was added, and the mixture was fully stirred and mixed for use.

[0064] Sodium aluminate solution 10: react 25wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 72wt% in an autoclave at 0.1MPa and 135°C for 6 hours, control the molar ratio of Al2O3 to Na2O to be 1:1.69, the Al2O3 concentration in the sodium aluminate solution is 365g / L, and the Na2O concentration is 375g / L, then add solid sodium hydroxide accounting for 9% of the total mass of the sodium aluminate solution, stir and mix thoroughly for standby use.

[0065] Preparation of silica-alumina gel

[0066] The element content in silica-alumina gel is calculated after being determined by chemical titration, and the density is determined by a pycnometer.

[0067] Silica-alumina gel 1: 900 g of coal-based kaolin was activated at 900°C for 120 min, then mixed with 15 mol / L formic acid solution, treated at a liquid-to-solid ratio of 4 and 100°C for 90 min, with a pH value of 2.8, and then slowly added with NaY mother liquor with a SiO2 concentration of 40 g / L and a Na2O concentration of 20 g / L. The mixture was aged at 30°C for 240 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 50%, Al2O3 15%, Na2O 12%, solid content 46%, and density 1.1.

[0068] Silica-alumina gel 2: 500 g of soft kaolin was activated at 600°C for 100 min, then mixed with 0.1 mol / L hydrochloric acid solution, treated at 50°C for 10 min at a liquid-to-solid ratio of 15, with a pH value of 3.9, and then slowly added with NaY mother liquor with a SiO2 concentration of 60 g / L and a Na2O concentration of 30 g / L. The mixture was aged at 100°C for 10 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 65%, Al2O3 20%, Na2O 14%, solid content 21%, and density 1.4.

[0069] Silica-alumina gel 3: 300 g of halloysite was activated at 700°C for 20 min, mixed with 3 mol / L sulfuric acid solution, treated at 80°C for 30 min at a liquid-to-solid ratio of 10, with a pH value of 3.5, and then NaY mother liquor with a SiO2 concentration of 52 g / L and a Na2O concentration of 23 g / L was slowly added. The mixture was aged at 80°C for 30 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 60%, Al2O3 18%, Na2O 13%, solid content 33%, and density 1.1.

[0070] Silica-alumina gel 4: 400 g of attapulgite was activated at 800°C for 80 min, then mixed with 10 mol / L citric acid solution, treated at 60°C for 60 min at a liquid-to-solid ratio of 8, pH value was 4.1, then NaY mother liquor with SiO2 concentration of 41 g / L and Na2O concentration of 32 g / L was slowly added, aged at 50°C for 200 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 58%, Al2O3 16%, Na2O 12%, solid content 20%, and density 1.23.

[0071] Silica-alumina gel 5: 300 g of sepiolite was activated at 650°C for 40 min, mixed with 5 mol / L phosphoric acid solution, treated at 70°C for 70 min at a liquid-to-solid ratio of 13, with a pH value of 4.5, and then NaY mother liquor with a SiO2 concentration of 44 g / L and a Na2O concentration of 24 g / L was slowly added. The mixture was aged at 50°C for 150 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 63%, Al2O3 19%, Na2O 12%, solid content 10%, and density 1.13.

[0072] Silica-alumina gel 6: 500 g of palygorskite was activated at 750°C for 60 min, mixed with 8 mol / L oxalic acid solution, treated at 40°C for 20 min at a liquid-to-solid ratio of 6, with a pH value of 4.8, and then slowly added with NaY mother liquor with a SiO2 content of 53 g / L and a Na2O concentration of 27 g / L. The mixture was aged at 70°C for 100 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 62%, Al2O3 15%, Na2O 12%, solid content 32%, and density 1.33.

[0073] Silica-alumina gel 7: 600 g of hard kaolin was activated at 850°C for 30 min, mixed with 2 mol / L acetic acid solution, treated at a liquid-to-solid ratio of 14 and 90°C for 40 min, with a pH value of 5.7, and then slowly added with NaY mother liquor with a SiO2 content of 43 g / L and a Na2O concentration of 23 g / L. The mixture was aged at 50°C for 170 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 58%, Al2O3 15%, Na2O 12%, solid content 18%, and density 1.17.

[0074] Silica-alumina gel 8: 300 g of soft kaolin was activated at 700°C for 70 min, mixed with 14 mol / L citric acid solution, treated at a liquid-to-solid ratio of 12 and 30°C for 90 min, with a pH value of 5.9, and then slowly added with NaY mother liquor with a SiO2 content of 45 g / L and a Na2O concentration of 25 g / L. The mixture was aged at 60°C for 130 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 59%, Al2O3 17%, Na2O 12%, solid content 25%, and density 1.25.

[0075] Silica-alumina gel 9: 500 g of halloysite was activated at 600°C for 50 min, mixed with 4 mol / L phosphoric acid solution, treated at 80°C for 50 min at a liquid-to-solid ratio of 4, pH value of 3.0, then slowly added with NaY mother liquor with SiO2 of 64 g / L and Na2O concentration of 30 g / L, aged at 90°C for 60 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 64%, Al2O3 19%, Na2O 14%, solid content 10%, and density 1.10.

[0076] Silica-alumina gel 10: 300 g of sepiolite was activated at 800°C for 90 min, mixed with 12 mol / L oxalic acid solution, treated at a liquid-to-solid ratio of 7 and 50°C for 90 min, with a pH value of 3.3, and then NaY mother liquor with a SiO2 content of 56 g / L and a Na2O concentration of 26 g / L was slowly added. The mixture was aged at 20°C for 90 min, and then filtered and washed to prepare silica-alumina gel. The quality data of the silica-alumina gel are: SiO2 55%, Al2O3 16%, Na2O 12%, solid content 26%, and density 1.34.

[0077] Preparation of directing agent

[0078] Directing agent 1: Weigh 100g of the above-mentioned fresh sodium aluminate solution 1, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.2), water glass and solid sodium hydroxide (calculated as alumina as the directing agent, the amount of the alkali added accounts for 1% of the total mass of the directing agent), and age at 35°C for 23 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 10:1:10.

[0079] Directing agent 2: Weigh 130g of the above-mentioned fresh sodium aluminate solution 2, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.1), water glass and solid sodium carbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 10% of the total mass of the directing agent), and age at 30°C for 20 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 20:1:20.

[0080] Directing agent 3: Weigh 180g of the above-mentioned fresh sodium aluminate solution 3, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.01), water glass and solid sodium bicarbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 5% of the total mass of the directing agent), and age at 33°C for 18 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 20:1:15.

[0081] Directing agent 4: Weigh 140 g of the above-mentioned fresh sodium aluminate solution 4, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.03), water glass and solid sodium carbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 8% of the total mass of the directing agent), and age at 30°C for 16 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 15:1:10.

[0082] Directing agent 5: Weigh 170g of the above-mentioned fresh sodium aluminate solution 5, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.15), water glass and solid sodium hydroxide (calculated as alumina as the directing agent, the amount of the alkali added accounts for 6% of the total mass of the directing agent), and age at 37°C for 12 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 15:1:20.

[0083] Directing agent 6: Weigh 130 g of the above-mentioned fresh sodium aluminate solution 6, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.18), water glass, solid sodium carbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 4% of the total mass of the directing agent), and age at 40°C for 8 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 10:1:20.

[0084] Directing agent 7: Weigh 200 g of the above-mentioned fresh sodium aluminate solution 7, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.05), water glass and solid sodium bicarbonate (the directing agent is calculated as alumina, and the amount of the alkali added accounts for 3% of the total mass of the directing agent), and age at 32°C for 13 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 18:1:16.

[0085] Directing agent 8: Weigh 400 g of the above-mentioned fresh sodium aluminate solution 8, and add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.08), water glass and solid sodium carbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 9% of the total mass of the directing agent), and age at 36°C for 10 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 13:1:18.

[0086] Directing agent 9: Weigh 500 g of the fresh sodium aluminate solution 9, add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.17), water glass and solid sodium bicarbonate (calculated as alumina as the directing agent, the amount of the alkali added accounts for 7% of the total mass of the directing agent), and age at 38°C for 22 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 19:1:13.

[0087] Directing agent 10: Weigh 300 g of the fresh sodium aluminate solution 10, add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.12), water glass, solid sodium hydroxide (calculated as alumina for the directing agent, the amount of alkali added accounts for 2% of the total mass of the directing agent), and age at 31°C for 24 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 12:1:17.

[0088] Specific analysis method:

[0089] The crystallinity of the Y-type molecular sieve is determined by X-ray diffraction method on a D / max-3C X-ray powder diffractometer manufactured by Rigaku Corporation of Japan. The specific operation method refers to the standard Q / SYLS 0596-2002.

[0090] The silicon-aluminum ratio of Y-type molecular sieve is tested by X-ray powder diffraction method, and the specific operation method refers to standard Q / SYLS0573~2002.

[0091] The total pore volume of the Y-type molecular sieve was measured using an ASAP 2460 fully automatic specific surface area analyzer produced by Micromeritics, USA.

[0092] Example 1

[0093] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0094] Weigh 500g of silica sol, slowly add 400g of the above-mentioned silica-alumina gel 1, then add 123g of the above-mentioned directing agent 1, stir thoroughly for 30min, then slowly add an aluminum sulfate solution with a concentration of 88g / L, stir for 20min, and finally add sodium aluminate solution 1 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1:1:6; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 100°C for 40 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.5, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0095] The Y-type molecular sieve was subjected to XRD test, and the results were as follows Figure 1 As shown by Figure 1 It can be seen that the molecular sieve prepared in the present invention has a complete crystal form and does not contain other impurity crystals.

[0096] Example 2

[0097] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0098] Weigh 200g of white carbon black, slowly add 100g of the above-mentioned silica-alumina gel 2, then add 78g of the above-mentioned directing agent 2, stir thoroughly for 30min, then slowly add aluminum chloride, stir for 20min, finally add sodium aluminate solution 2 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.9:1:5.7; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 96°C for 36 hours, filter the solid, wash with deionized water until the pH of the washing liquid is 10.2, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0099] Example 3

[0100] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0101] Weigh 300g of water glass, slowly add 140g of the above-mentioned silica-alumina gel 3, then add 112g of the above-mentioned directing agent 3, stir thoroughly for 30min, then slowly add aluminum phosphate, stir for 20min, add the above-mentioned fresh sodium aluminate solution 3 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.5:1:5.8; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 96°C for 36 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.1, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0102] Example 4

[0103] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0104] Weigh 500g of water glass, slowly add 300g of the above-mentioned silica-alumina gel 4, then add 132g of the above-mentioned directing agent 4, fully stir for 30min, then slowly add aluminum nitrate, stir for 20min, and finally add sodium aluminate solution 4 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.1:1:6.0; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 98°C for 32 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.3, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0105] Example 5

[0106] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0107] Weigh 550g of water glass, slowly add 340g of the above-mentioned silica-alumina gel 5, then add 148g of the above-mentioned directing agent 5, fully stir for 30min, then slowly add aluminum acetate, stir for 20min, and finally add the above-mentioned fresh sodium aluminate solution 5 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.6:1:5.3; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 97°C for 26 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.4, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0108] Example 6

[0109] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0110] Weigh 350g of water glass, slowly add 167g of the above-mentioned silica-alumina gel 6, then add 102g of the above-mentioned directing agent 6, stir thoroughly for 30min, then slowly add aluminum formate, stir for 20min, and finally add sodium aluminate solution 6 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.8:1:5.9; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 95°C for 22 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.5, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0111] Example 7

[0112] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0113] Weigh 550g of water glass, slowly add 345g of the above-mentioned silica-alumina gel 7, then add 190g of the above-mentioned directing agent 7, fully stir for 30min, then slowly add a 90g / L aluminum sulfate solution, stir for 20min, and finally add sodium aluminate solution 7 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.4:1:5.0; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 97°C for 20 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.0, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0114] Example 8

[0115] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0116] Weigh 350g of water glass, slowly add 167g of the above-mentioned silica-alumina gel 8, then add 100g of the above-mentioned directing agent 8, stir thoroughly for 30min, then slowly add aluminum fluoride, stir for 20min, and finally add sodium aluminate solution 8 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.4; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 92°C for 38 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.3, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0117] Example 9

[0118] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0119] Weigh 390g of water glass, slowly add 160g of the above-mentioned silica-alumina gel 9, then add 140g of the above-mentioned directing agent 9, stir thoroughly for 30min, then slowly add aluminum formate, stir for 20min, and finally add sodium aluminate solution 9 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.7; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 100°C for 20 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.2, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0120] Example 10

[0121] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0122] Weigh 290g of water glass, slowly add 120g of the above-mentioned silica-alumina gel 10, then add 110g of the above-mentioned directing agent 10, stir thoroughly for 30min, then slowly add aluminum nitrate, stir for 20min, and finally add the above-mentioned fresh sodium aluminate solution 10 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.2:1:5.6; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 94°C for 30 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.4, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0123] Embodiment 11

[0124] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0125] Weigh 500g of silica sol, slowly add 400g of the above-mentioned silica-alumina gel 1, then add 123g of the above-mentioned directing agent 1, stir thoroughly for 30min, then slowly add an aluminum sulfate solution with a concentration of 88g / L, stir for 20min, and finally add a sodium aluminate solution 1 that has been placed at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1:1:6; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 100°C for 40 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.5, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0126] Example 12

[0127] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0128] Weigh 200g of white carbon black, slowly add 100g of the above-mentioned silica-alumina gel 2, then add 78g of the above-mentioned directing agent 2, stir thoroughly for 30min, then slowly add aluminum chloride, stir for 20min, add sodium aluminate solution 2 that has been left at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.9:1:5.8; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 96°C for 36 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.2, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0129] Embodiment 13

[0130] This embodiment provides a method for synthesizing a Y-type molecular sieve, and the specific steps are as follows:

[0131] Weigh 350g of water glass, slowly add 167g of the above-mentioned silica-alumina gel 8, then add 100g of the above-mentioned directing agent 8, stir thoroughly for 30min, then slowly add aluminum fluoride, stir for 20min, finally add sodium aluminate solution 8 that has been left at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.4; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 92°C for 38 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.3, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0132] Comparative Example 1

[0133] The Y-type molecular sieve synthesis method provided in this comparative example is similar to that in Example 3, except that the sodium aluminate solution is different, and the sodium aluminate solution in this comparative example is used when preparing the directing agent. The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0134] Sodium aluminate solution D-1: 40wt% sodium hydroxide solution and aluminum hydroxide powder with an Al2O3 content of 90wt% were reacted in an autoclave at 0.3MPa and 100°C for 2 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:1.08. The Al2O3 concentration in the sodium aluminate solution was 150g / L, and the Na2O concentration was 99g / L.

[0135] Directing agent D-1: Weigh 180g of the above-mentioned fresh sodium aluminate solution D-1, and slowly add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.01), water glass, solid sodium bicarbonate (the directing agent is calculated as alumina, and the amount of this alkali added accounts for 5% of the total mass of the directing agent) thereto, and age at 33°C for 18 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 20:1:15.

[0136] Weigh 300g of water glass, slowly add 140g of the above-mentioned silica-alumina gel 3, then add 112g of the above-mentioned directing agent D-1, stir thoroughly for 30min, then slowly add aluminum phosphate, stir for 20min, add the above-mentioned fresh sodium aluminate solution D-1 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.5:1:5.8; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 96°C for 36 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.1, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0137] Comparative Example 2

[0138] This comparative example is similar to Example 8, except that silicon powder is not added when preparing the directing agent. The Y-type molecular sieve synthesis method provided in this comparative example includes the following steps:

[0139] Directing agent D-2: Weigh 400 g of the fresh sodium aluminate solution 8, add water glass and solid sodium carbonate (the amount of the directing agent based on alumina accounts for 9% of the total mass of the directing agent), and age at 36° C. for 10 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 13:1:18.

[0140] Weigh 350g of water glass, slowly add 167g of the above-mentioned silica-alumina gel 8, then add 100g of the above-mentioned directing agent D-2, fully stir for 30min, then slowly add aluminum fluoride, stir for 20min, and finally add sodium aluminate solution 8 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.4; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 92°C for 38 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.3, and then dry at 120°C to obtain a Y-type molecular sieve.

[0141] Comparative Example 3

[0142] The Y-type molecular sieve synthesis method provided in this comparative example is similar to that in Example 1, except that a different sodium aluminate solution is used. The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0143] Sodium aluminate solution D-3: 25wt% sodium hydroxide solution and aluminum hydroxide powder with an Al2O3 content of 60wt% were reacted in an autoclave at 0.4MPa and 140°C for 6 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:0.86. The Al2O3 concentration in the sodium aluminate solution was 150g / L, and the Na2O concentration was 79g / L.

[0144] Directing agent D-3: Weigh 100 g of the fresh sodium aluminate solution D-3, add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.2), water glass and solid sodium hydroxide (calculated as alumina as the directing agent, the amount of the alkali added accounts for 1% of the total mass of the directing agent), and age at 35°C for 23 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 10:1:10.

[0145] Weigh 500g of silica sol, slowly add 400g of the above-mentioned silica-alumina gel 1, then add 123g of the above-mentioned directing agent D-3, stir thoroughly for 30min, then slowly add an aluminum sulfate solution with a concentration of 88g / L, stir for 20min, add the above-mentioned sodium aluminate solution D-3 that has been placed at room temperature for 10 days to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1:1:6; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 100℃ for 40 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.5, and then dry at 120℃ for 12h to obtain a Y-type molecular sieve.

[0146] Comparative Example 4

[0147] This comparative example is similar to Example 5, except that the silica-alumina gel is different. The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0148] Silica-alumina gel D-4: NaY mother liquor with SiO2 content of 44 g / L and Na2O concentration of 24 g / L was used and aged with aluminum acetate at 50°C for 150 min. Silica-alumina gel was prepared by filtration and washing. The quality data of the silica-alumina gel are: SiO2 63%, Al2O3 19%, Na2O 12%, solid content 10%, and density 1.13.

[0149] Weigh 550g of water glass, slowly add 340g of the above-mentioned silica-alumina gel D-4, then add 148g of the above-mentioned directing agent 5, fully stir for 30min, then slowly add aluminum acetate, stir for 20min, add the above-mentioned fresh sodium aluminate solution 5 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.6:1:5.3; after rapid stirring for 30min, transfer to a synthesis kettle, crystallize at 97°C for 26 hours, wash the filtered solid with deionized water until the pH of the washing liquid is 10.4, and then dry at 120°C for 12h to obtain a Y-type molecular sieve.

[0150] Comparative Example 5

[0151] The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0152] Sodium aluminate solution D-5: 500 ml of a 31.8% sodium hydroxide solution and 223.8 g of aluminum hydroxide powder with an Al2O3 content of 62.7% were added to a stirred reactor at a pressure of 0.2 MPa; the reaction temperature was 125°C, and the reaction time was 6 hours to prepare the sodium aluminate solution used.

[0153] Silica-alumina gel D-5: The filtrate of the aged qualified material in the NaY preparation step with a SiO2 concentration of 45.8 g / L and a Na2O concentration of 25.2 g / L was reacted with an aluminum sulfate solution with an Al2O3 concentration of 90.2 g / L, and silica-alumina gel was prepared after filtration and washing. The quality data of the silica-alumina gel are: SiO2 61.9%, Al2O3 16.6%, Na2O 13.7%, solid content 11.9%, and density 1.0956.

[0154] Directing agent D-5: 135.6 ml of sodium aluminate solution with an Al2O3 concentration of 150.5 g / L and a Na2O concentration of 180.3 g / L and 270.6 ml of liquid caustic soda with a concentration of 31% are added to a stirred reactor. After stirring evenly, 718.2 ml of water glass solution with a SiO2 concentration of 250.6 g / L and a modulus of 3.25 are added. The aging temperature is controlled at 28°C and the product is aged for 20 hours. After aging, 169 ml of chemical water is added. The resulting product is the directing agent solution.

[0155] Take 255.9 ml of the above-mentioned silica-alumina gel D-5, 294.2 ml of water glass solution (the SiO2 concentration in the water glass solution is 250.6 g / L and the modulus is 3.25), 52.8 ml of the above-mentioned fresh sodium aluminate solution D-5, 50 ml of the directing agent D-5 and 65.8 ml of aluminum sulfate solution with an Al2O3 concentration of 90.5 g / L, and add them into the colloid reaction kettle at a certain flow rate to ensure that the molar ratio of Na2O, Al2O3 and SiO2 is 2-3.5:1:8-10. The stirring time is 40 minutes, the temperature is raised to 98°C, and it is aged for 28 hours. The obtained product is washed and filtered to obtain a Y-type molecular sieve.

[0156] The Y-type molecular sieves prepared in each embodiment and comparative example were respectively compared in detail in terms of crystallinity, silicon-aluminum ratio, total pore volume, reduction in salt emissions and total cost reduction, wherein the reduction in salt emissions and total cost reduction were based on comparative example 5. The specific results are shown in Table 1 below.

[0157] Table 1

[0158]

[0159]

[0160] It can be seen from the data in the above table that, when Example 3 is compared with Comparative Example 1, after adding a stabilizer, the instability problem of the sodium aluminate solution is fundamentally solved. While ensuring the high crystallinity of the molecular sieve, the salt discharge and total cost are reduced by about 12% and 16% respectively compared with Comparative Example 1. In addition, it can be seen from the comparison results of Example 8 and Comparative Example 2 that after adding silicon powder in the preparation process of the guiding agent, the role of "silicon island" aggregation and promoting crystallization synthesis is fully utilized, so that the crystallinity of the Y-type molecular sieve is increased by 17 units. And by comparing Example 1 and Comparative Example 3, it can be seen that if no stabilizer is added, the sodium aluminate solution can easily parse out aluminum-containing compounds, resulting in failure, poor synthesis efficiency, and thus affecting the synthesis effect. The crystallinity is reduced from 90% to 80%, which significantly affects the synthesis effect, and the total cost reduction rate is low. Comparative Example 4 is compared with Example 5. It can be seen that the present invention uses natural minerals after activation and acid treatment, which can not only be used as an aluminum source, but also significantly increase the total pore volume. Although Comparative Example 5 can ensure smooth crystallization, it has no advantages in terms of salt emission and total cost reduction because it is not a low-sodium gel ratio.

[0161] In summary, the molecular sieve prepared by the preparation method of the Y-type molecular sieve provided by the present invention has a high silicon-aluminum ratio and mesopores, and the salt emission is greatly reduced, and the total synthesis cost is also significantly reduced, which reduces costs and increases efficiency while having broader application prospects.

[0162] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a mesoporous Y-type molecular sieve, characterized in that: The steps include: After the silicon source, the directing agent and the silica-alumina gel are uniformly mixed, the aluminum source and the sodium metaaluminate solution are added in sequence to form a gel, and after crystallization and post-treatment, a Y-type molecular sieve is obtained; Wherein, the guiding agent is obtained by mixing and aging sodium aluminate solution, silicon powder, silicon source and alkaline compound; The silica-alumina gel is obtained by activating and acid-treating natural minerals and mixing with NaY mother liquor for aging; The sodium aluminate solution used in forming the gel and preparing the guiding agent is the same, the sodium aluminate solution contains a stabilizer, the concentration of Al2O3 is 190-400g / L, the concentration of Na2O is 210-400g / L, and the molar ratio of Na2O to Al2O3 is controlled to be 0.86-3.46:

1. The molar ratio of Na2O, Al2O3 and SiO2 in the gel is (1.0-1.9):1:(5-7).

2. The preparation method according to claim 1, characterized in that The acid treatment is to treat the activated natural mineral with an acid solution at a pH of 2.8 to 6.0 and 20 to 100° C. for 10 to 90 minutes; The concentration of the acid solution is 0.1 to 15 mol / L; The liquid-to-solid ratio of the activated natural mineral to the acid solution is 4-15.

3. The preparation method according to claim 1, characterized in that: The activation temperature is 600-900° C. and the activation time is 20-100 minutes.

4. The preparation method according to claim 2, characterized in that: The natural mineral is selected from one or more of soft and hard kaolin, coal-based kaolin, halloysite, attapulgite, sepiolite and palygorskite; The acid solution is selected from an inorganic acid solution or an organic acid solution, the inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, and the organic acid is selected from one or more of formic acid, citric acid, oxalic acid, and acetic acid.

5. The preparation method according to claim 1, characterized in that: During the preparation of the silica-alumina gel, the aging temperature is 20-100° C. and the aging time is 10-240 min.

6. The preparation method according to claim 1, characterized in that: The NaY mother liquor has a SiO2 concentration of 40 to 65 g / L and a Na2O concentration of 20 to 40 g / L; The quality data of the silica-alumina gel are: SiO2 50%-65%, Al2O3 15%-20%, Na2O 12-15%, solid content 10%-50%, and density 1.0-1.

4.

7. The preparation method according to claim 1, characterized in that: The sodium aluminate solution is obtained by reacting 25wt% to 50wt% sodium hydroxide solution with aluminum hydroxide powder having an Al2O3 content of not less than 60wt% at 0.1 to 0.4MPa and 100 to 140°C, and then adding a stabilizer; The stabilizer is selected from one or more of sodium carbonate, sodium bicarbonate, and ammonia water; Based on the total mass of the sodium hydroxide solution and the aluminum hydroxide powder being 100%, the added mass of the stabilizer is 1% to 10%.

8. The preparation method according to claim 1, characterized in that: The molar ratio of Na2O, Al2O3 and SiO2 in the directing agent is (10-20):1:(10-20); The preparation of the directing agent comprises the following steps: adding the alkaline compound, the silicon powder and the silicon source into the sodium aluminate solution, mixing them evenly, and then standing and aging at 30-40° C. for 6-24 hours.

9. The preparation method according to claim 8, characterized in that: The alkaline compound is selected from any one of sodium hydroxide, sodium carbonate and sodium bicarbonate; The mass ratio of the alkaline compound to the directing agent is 0.01 to 0.1 based on Al2O3; Calculated in terms of SiO2, the molar ratio of the silicon powder to the directing agent is 0.01 to 0.

2.

10. The preparation method according to claim 1, characterized in that: The crystallization is hydrothermal crystallization, the temperature of the hydrothermal crystallization is 90-100° C., and the time is 16-40 hours.

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