Method for preparing coal gangue / aluminum ash-based SAPO-20 zeolite by regulating alkali-ash ratio

Abstract

The invention discloses a method for preparing coal gangue / aluminum ash-based SAPO-20 zeolite by regulating the alkali-ash ratio, belongs to the field of resource recycling, is used for zeolite, and comprises the following steps: mixing a mixture of coal gangue sample powder and aluminum ash sample powder in a silicon-aluminum molar ratio of (1: 1)-(2: 1) with alkali-ash mixed powder in which the mass ratio of sodium hydroxide to coal gangue is 0.4-2.0; the preparation method comprises the following steps: putting the raw materials into a muffle furnace, roasting, naturally cooling to room temperature, grinding, filtering to be neutral, grinding to pass through a 200-mesh sieve, mixing with deionized water according to a weight ratio, thermally sealing in a hydrothermal reaction kettle, naturally cooling to room temperature, washing, filtering to be neutral, drying, passing through the 200-mesh sieve, and sealing and storing. According to the technical scheme, the SAPO-20 zeolite with high specific surface area and good crystallinity can be synthesized more stably by optimizing the alkali-ash ratio, simplifying the production process and reducing the dependence on accurate control in the production process, and the method is suitable for large-scale industrial application.

Description

Technical Field

[0001] This application belongs to the field of resource recycling. Specifically, it particularly relates to a method for regulating the alkali-ash ratio to prepare coal gangue / aluminum ash-based SAPO-20 zeolite. Background Art

[0002] Coal gangue is one of the by-products of coal mining, and aluminum ash is one of the by-products of industrial production. If the above two are not properly treated, it will lead to serious environmental problems. First of all, coal gangue is generally stacked in storage sites, which not only occupies a large amount of land resources, but also has safety hazards such as fires, landslides, collapses, and dust explosions. Secondly, the heavy metals contained in coal gangue may seep into the soil of the stacking site, causing soil and water pollution and endangering the ecological environment.

[0003] If aluminum ash is not properly treated, it will cause air, water, and soil pollution, and aluminum ash dust may also cause respiratory diseases or skin diseases, and even lead to metal poisoning.

[0004] Therefore, the treatment of coal gangue and aluminum ash can not only realize the effective recycling of solid waste resources, but also reduce environmental pollution, which has important economic and social value.

[0005] As a silicate crystal with a unique pore structure, zeolite's good gas adsorption performance makes it perform excellently in the field of CO2 capture and separation. The traditional zeolite synthesis method has high complexity and high cost. For example, the patent document with the Chinese patent publication number CN118439627A discloses the following technical content: ball-milling and pulverizing coal gangue to obtain coal gangue powder, performing decarbonization activation treatment on the coal gangue powder to obtain carbon-free coal gangue powder; mixing the carbon-free coal gangue powder with sodium hydroxide powder according to the ratio to obtain the first mixed powder, performing alkali melting activation treatment on the first mixed powder to obtain activated carbon-free coal gangue powder; mixing the activated carbon-free coal gangue powder with aluminum ash powder according to the ratio to obtain the second mixed powder, aging the second mixed powder with deionized water according to the ratio to obtain the aged material; performing crystallization treatment on the aged material to obtain the crystallized material, and washing and drying to obtain the lamellar stacked spherical molecular sieve.

[0006] In the prior art document of CN118439627A, the prepared molecular sieve is mainly used for specific catalytic and adsorption applications and cannot perform better in a wider range of industrial applications, especially in fields such as CO2 adsorption that require high surface area and stability.

[0007] Therefore, the applicant of this application endeavors to provide a zeolite synthesis method that can simplify the process, reduce costs, and also realize the recycling of coal gangue and aluminum ash. Summary of the Invention

[0008] The purpose of the present application is to provide a method for regulating the alkali-ash ratio to prepare coal gangue / aluminum ash-based SAPO-20 zeolite, which can optimize the alkali-ash ratio, simplify the production process, reduce the dependence on precise control in the production process, and can more stably synthesize SAPO-20 zeolite with a high specific surface area and good crystallinity, being suitable for large-scale industrial applications.

[0009] To achieve the above object, the present application is realized through the following technical solutions: A method for regulating the alkali-ash ratio to prepare coal gangue / aluminum ash-based SAPO-20 zeolite described in the present application has the following steps: S1. Respectively use 3 mol / L - 7 mol / L HCl for coal gangue and aluminum ash, according to a solid-liquid ratio of 1:5 - 1:10, and magnetically stir at room temperature for 1 h - 5 h to remove the metal impurities contained in the coal gangue and aluminum ash respectively, and obtain pickled coal gangue finished product and pickled aluminum ash finished product; S2. Wash and filter the pickled coal gangue finished product and pickled aluminum ash finished product obtained in step S1 with deionized water repeatedly until the pH is close to 7, then place them in an oven at a temperature of 60°C - 110°C for drying. After drying, grind them at room temperature and pass through a 200-mesh sieve respectively to obtain coal gangue sample powder and aluminum ash sample powder; S3. Take an appropriate amount of the coal gangue sample powder and aluminum ash sample powder prepared in step S2, regulate the silicon-aluminum molar ratio to 1:1 - 2:1, and obtain a mixed sample after uniform mixing; S4. Respectively take a mixed powder with an alkali-ash ratio of 0.4 - 2.0 of sodium hydroxide to coal gangue by mass, mix it evenly with the mixed sample obtained in step S3, and place it in a muffle furnace to be heated uniformly at a heating rate of 3°C / min - 10°C / min to 500°C - 800°C, roast for 2 h - 4 h, and then naturally cool to room temperature; S5. Take out the roasted product obtained in step S4, grind it, wash and filter it with deionized water repeatedly until the pH is close to 7, dry it at a temperature of 60°C - 110°C, naturally cool to room temperature, then grind it and pass through a 200-mesh sieve for standby; S6. Mix the product obtained in step S5 with deionized water according to a weight ratio of 1:5 - 1:10 and mix it evenly, and place it in a hydrothermal reaction kettle. Under the temperature condition of 80°C - 200°C, carry out hydrothermal synthesis for 6 h - 48 h, and then naturally cool to room temperature; S7. Take out the synthetic product obtained in step S6, wash and filter it with deionized water until the pH is close to 7, dry it at a temperature of 60 - 110°C, naturally cool to room temperature, then grind it to pass through a 200-mesh sieve, and store it sealed.

[0010] As a preferred technical solution, in the present application, it further includes: S8. Activation of the adsorbed sample: Take the finished product sealed and stored in step S7. First, heat it to 80°C to 120°C under the atmosphere of N2, keep it at a constant temperature for 30 min to 60 min under the condition that the gas flow rate is 50 ml / min to 100 ml / min, and record the relevant experimental data; S9. When the sample in step S8 naturally cools down to below 50°C under the N2 atmosphere, start to introduce CO2 gas. The flow rate of the introduced CO2 gas is 50 ml / min to 100 ml / min, keep it at a constant temperature for 60 min to 120 min, and record the relevant data.

[0011] As a preferred technical solution, in the present application, under the condition of an alkali-ash ratio of 1:1.6 of the mass of coal gangue powder to the mass of sodium hydroxide powder, the specific surface area of the synthesized SAP-20 zeolite is 175.62 m 2 / g, and the CO2 adsorption capacity is 27.92 mg / g.

[0012] Compared with the prior art, the beneficial effects of the present application are as follows: 1. When the alkali-ash ratio of the SAPO-20 zeolite prepared in the present application is 1.6, the obtained zeolite has the largest specific surface area, which is 175.62 m² / g, and the CO2 adsorption capacity is 27.92 mg / g. It has a relatively high specific surface area and good crystallinity, and is suitable for the capture and emission reduction of greenhouse gases.

[0013] 2. By adjusting the alkali-ash ratio in the present application, the preparation process of the zeolite is simplified, making the preparation process of the zeolite simpler and the cost lower, and it is suitable for large-scale industrial production.

[0014] 3. The present application can realize the resource utilization of coal gangue and aluminum ash solid waste. Using coal gangue and aluminum ash as raw materials to produce SAPO-20 zeolite conforms to the concept of green environmental protection. Description of the Drawings

[0015] Figure 1 It is the SEM image of the coal gangue / aluminum ash-based SAPO-20 zeolite synthesized under the condition of an alkali-ash ratio of 1.6:1.

[0016] Figure 2 It is the XRD pattern of Examples 1 to 5.

[0017] Figure 3 It is the CO2 adsorption curve of Example 6.

[0018] Figure 4 It is the comparison table of BET data and CO2 adsorption capacity of coal gangue and SAPO-20 zeolite. Detailed Embodiments

[0019] The technical solution described in this application is further described below in conjunction with the accompanying drawings and embodiments.

[0020] Example 1

[0021] S1. Use 3mol / L~7mol / L HCl for coal gangue and aluminum ash respectively, according to the solid-liquid ratio of 1:5~1:10 (mass: volume), at room temperature, and stir magnetically for 1h~5h to remove metal and other impurities contained in the coal gangue and aluminum ash through the HCl solution, and obtain the coal gangue pickling product and aluminum ash pickling product that can be used for subsequent steps.

[0022] S2. The finished pickled coal gangue product and the finished pickled aluminum ash product obtained in step S1 are repeatedly washed and filtered with deionized water until the pH value of the washed pickled coal gangue product approaches 7 and the pH value of the washed aluminum ash product approaches 7, and then both are placed at a temperature of 60°C to 110°C for drying. After drying, they are cooled to room temperature, and ground at room temperature and passed through a 200-mesh sieve to obtain coal gangue sample powder and aluminum ash sample powder for use in subsequent steps.

[0023] Step S3, taking a portion of the coal gangue sample powder and the aluminum ash sample powder and mixing them thoroughly in a silicon-aluminum molar ratio of 1:1 to 2:1; S4, take part of the gangue sample powder obtained in step S2 and mix it evenly with the sodium hydroxide powder, the ratio of the mass of the sodium hydroxide powder to the mass of the gangue powder is equal to 0.4; and mix it evenly with the powder with a silicon-aluminum molar ratio of 1:1 in step S3, and place it in a muffle furnace, and heat it uniformly to 800°C at a heating rate of 10°C / min in the muffle furnace and roast it for 2h, and then cool it naturally to room temperature; S5, washing and filtering the calcined product obtained in step S4 until the pH value is close to 7 (i.e., the product after washing and filtering is neutral), drying at 105° C., grinding and passing through a 200-mesh sieve; S6, mixing the product obtained in step S5 with deionized water in a mass ratio of 1:6, placing the mixture in a hydrothermal reactor for hydrothermal synthesis at 150° C. for 12 h, and then cooling the mixture naturally to room temperature; S7. Take out the synthetic product obtained in step S6, wash it with deionized water until the pH value is close to 7 (that is, the product after washing and filtration is neutral), dry it at 105° C., grind it through a 200-mesh sieve, and obtain a finished product of coal gangue / aluminum ash-based SAPO-20 zeolite, which is recorded as the product of Example 1 and sealed for storage.

[0024] Example 2

[0025] Compared with the technical solution described in Example 1, adjust the mass of the added sodium hydroxide powder, that is, adjust the mass ratio of the sodium hydroxide powder to the coal gangue powder to 0.8. The remaining steps and parameters are the same as those described in Example 1. Denote the finally obtained finished coal gangue / aluminum ash-based SAPO-20 zeolite as the product of Example 2, and store it in a sealed manner.

[0026] Example 3

[0027] Compared with Example 2, adjust the mass ratio of the sodium hydroxide powder to the coal gangue powder in Example 2 to 1.2. The remaining steps and parameters are the same as those described in Example 2. Denote the finally obtained finished coal gangue / aluminum ash-based SAPO-20 zeolite as the product of Example 3, and store it in a sealed manner.

[0028] Example 4

[0029] Compared with Example 3, adjust the mass ratio of the sodium hydroxide powder to the coal gangue powder in Example 3 to 1.6. The remaining steps and parameters are the same as those described in Example 3. Denote the finally obtained finished coal gangue / aluminum ash-based SAPO-20 zeolite as the product of Example 4, and store it in a sealed manner.

[0030] Example 5

[0031] Compared with Example 4, adjust the mass ratio of the sodium hydroxide powder to the coal gangue powder in Example 4 to 2.0. The remaining steps and parameters are the same as those described in Example 4. Denote the finally obtained finished coal gangue / aluminum ash-based SAPO-20 zeolite as the product of Example 5, and store it in a sealed manner.

[0032] Example 6

[0033] In this example, select the condition that the mass ratio of the sodium hydroxide powder to the coal gangue powder in Step S2 is adjusted to 1.6, and measure the CO2 adsorption capacity of the prepared coal gangue / aluminum ash-based SAPO-20 zeolite: (1) Activation of the adsorption sample: Take 10 mg to 20 mg of the finished product, heat it to 80 °C to 120 °C in an N2 atmosphere, with a gas flow rate of 50 ml / min to 100 ml / min, keep it at a constant temperature for 30 min to 60 min, and record the relevant data.

[0034] (2) When the sample in Step (1) cools down to below 50 °C in an N2 atmosphere, start to introduce CO2 gas, with a gas flow rate of 50 ml / min to 100 ml / min, keep it at a constant temperature for 60 min to 120 min, and record the relevant data to obtain Figure 3 the CO2 gas adsorption curve shown.

[0035] Finally, although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for regulating the alkali-ash ratio to prepare coal gangue / aluminum ash-based SAPO-20 zeolite, which is characterized in that, The method has the following steps: S1. Respectively use HCl with a concentration of 3 mol / L to 7 mol / L to treat coal gangue and aluminum ash according to a solid-liquid ratio of 1:5 to 1:10, and magnetically stir for 1 h to 5 h at room temperature to remove the metal impurities contained in the coal gangue and aluminum ash respectively, and obtain pickled coal gangue products and pickled aluminum ash products; S2. Repeatedly wash and filter the pickled coal gangue products and pickled aluminum ash products prepared in step S1 with deionized water until the pH is close to 7, then dry them at a temperature of 60°C to 110°C, and after drying, grind them and pass through a 200-mesh sieve at room temperature to obtain coal gangue sample powder and aluminum ash sample powder; S3. Take an appropriate amount of the coal gangue sample powder and aluminum ash sample powder prepared in step S2, adjust the silicon-aluminum molar ratio to 1:1 to 2:1, and obtain a mixed sample after uniform mixing; S4. Respectively take a mixed powder with an alkali-ash ratio of 0.4 to 2.0 of sodium hydroxide to coal gangue, mix it evenly with the mixed sample obtained in step S3, and place it in a muffle furnace and heat it up uniformly at a heating rate of 3°C / min to 10°C / min to 500°C to 800°C, calcine for 2 h to 4 h, and then naturally cool to room temperature; S5. Take out the calcined product obtained in step S4, grind it, and repeatedly wash and filter it with deionized water until the pH is close to 7, dry it at a temperature of 60°C to 110°C, naturally cool to room temperature, grind it and pass through a 200-mesh sieve for standby; S6. Mix the product obtained in step S5 with deionized water according to a weight ratio of 1:5 to 1:10, place it in a hydrothermal reaction kettle, and carry out hydrothermal synthesis for 6 h to 48 h at a temperature of 80°C to 200°C, and then naturally cool to room temperature; S7. Take out the synthetic product obtained in step S6, wash and filter it with deionized water until the pH is close to 7, dry it at a temperature of 60 to 110°C, naturally cool to room temperature, grind it to pass through a 200-mesh sieve, and store it sealed.

2. A method for regulating the alkali-ash ratio to prepare coal gangue / aluminum ash-based SAPO-20 zeolite according to claim 1, characterized in that, It also includes: S8. Activation of the adsorption sample: Take the sealed product in step S7, first heat it up to 80°C to 120°C in an N2 atmosphere, keep it at a constant temperature for 30 min to 60 min under the condition of a gas flow rate of 50 ml / min to 100 ml / min, and record relevant experimental data; S9. When the sample in step S8 naturally cools to below 50°C in an N2 atmosphere, start to introduce CO2 gas, the flow rate of the introduced CO2 gas is 50 ml / min to 100 ml / min, keep it at a constant temperature for 60 min to 120 min, and record relevant data.

3. A method for preparing coal gangue / aluminum ash-based SAPO-20 zeolite by regulating the alkali-ash ratio according to claim 2, characterized in that: Under the condition of an alkali-ash ratio where the mass ratio of the coal gangue powder to the sodium hydroxide powder is 1:1.6, the specific surface area of the synthesized SAP-20 zeolite is 175.62 m 2 / g, and the CO2 adsorption capacity is 27.92 mg / g.

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