Apparatus and method for producing zeolite by staged reaction of fly ash

Abstract

This invention provides an apparatus and method for preparing zeolite by staged reaction of fly ash. The apparatus includes: a grading and screening unit that separates fly ash into fine, medium, and coarse particles according to particle size; a multi-stage reaction unit composed of at least three independently temperature-controlled jacketed reactors corresponding to the fine, medium, and coarse fly ash particles; and an online analysis unit for real-time detection of Si in the reaction solution. 4+ Al 3+ The system calculates the ion concentration and silicon-to-aluminum ratio; the feedback mixing unit receives the data from the online analysis unit and automatically adds aluminum or silicon sources based on the results; the crystallization and drying unit crystallizes the reaction solution prepared by the feedback mixing unit, and the crystallized product is then centrifuged, washed, and dried. This invention, through particle size classification and differentiated reaction condition design, ensures that all particle sizes of fly ash reach the optimal reaction state, making it economical and practical.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to an apparatus and method for preparing zeolite by staged reaction of fly ash. Background Technology

[0002] Fly ash, a major industrial solid waste emitted by coal-fired power plants, accounts for over 600 million tons annually in my country. Its main chemical components are SiO2 (40%-60%) and Al2O3 (20%-30%), providing a natural chemical basis for synthesizing zeolite molecular sieves. Zeolite molecular sieves, due to their regular pore structure and excellent adsorption properties, are widely used in water purification, gas separation, and catalyst carriers. Converting fly ash into zeolite achieves the resource utilization goal of "turning waste into treasure." However, existing fly ash-to-zeolite preparation technologies have the following shortcomings: The problem of uneven reaction is prominent: fly ash particles have a wide particle size distribution (usually 1-100μm). Fine particles have a large specific surface area and high reactivity, while coarse particles are difficult to activate due to the internal quartz and mullite crystals. Under uniform reaction conditions, fine particles often react excessively to generate amorphous impurities, while coarse particles react insufficiently, leading to waste of raw materials.

[0003] Insufficient precision in controlling the silicon-to-aluminum ratio: Zeolite performance (such as adsorption capacity and pore size distribution) is highly dependent on the product's silicon-to-aluminum ratio (Si / Al). For example, NaA-type zeolite has a Si / Al ratio of approximately 1, while NaX-type zeolite has a Si / Al ratio of approximately 2.5. However, the composition of fly ash from different power plants varies greatly (Si / Al ratio is usually between 1.5 and 3.5). Traditional methods only preset the silicon-to-aluminum ratio before the reaction, lacking a real-time monitoring and dynamic adjustment mechanism during the reaction process. This results in poor product performance stability, making it difficult to meet the requirements of industrial applications.

[0004] Low resource and energy efficiency: To ensure complete reaction of coarse particles, existing technologies generally use excessive alkali (NaOH is often 30%-50% of the fly ash mass) and long-term high-temperature reaction (10-24 hours), which not only increases alkali consumption and energy costs, but also generates a large amount of high-concentration alkaline waste liquid, which is difficult to treat and does not conform to the green and low-carbon industrial development direction.

[0005] Therefore, developing a technology and device for preparing zeolite from fly ash that can achieve precise particle size classification, controllable reaction process, and efficient resource utilization has become a key issue that the industry urgently needs to address.

[0006] Based on this, an apparatus and method for preparing zeolite by staged reaction of fly ash are proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an apparatus and method for preparing zeolite by staged reaction of fly ash, in order to address the shortcomings of the prior art mentioned above.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, an apparatus for the staged reaction of fly ash to prepare zeolite includes: The grading and screening unit separates fly ash into fine particles ≤45μm, medium particles 45~90μm, and coarse particles >90μm based on particle size, with a grading efficiency ≥95%. A multi-stage reaction unit, wherein the multi-stage reaction unit consists of at least three jacketed reactors with independent temperature control corresponding to fine-grained, medium-grained, and coarse-grained fly ash; The online analysis unit detects Si in the reaction solution in real time. 4+ Al 3+ Data on ion concentration and calculation of the silicon-to-aluminum ratio; A feedback adjustment unit receives the result data from the online analysis unit and automatically adds an aluminum source or a silicon source based on the result data; The crystallization and drying unit performs crystallization treatment on the reaction solution prepared by the feedback mixing unit, and the crystallized product is dried after centrifugation and washing. The control system is connected to the graded screening unit, the multi-stage reaction unit, the online analysis unit, the feedback mixing unit, and the crystallization drying unit to complete the control operation.

[0009] As a further explanation of the present invention, the grading and screening unit is specifically an air classifier, which is used to grade fly ash after removing metal impurities.

[0010] As a further explanation of the present invention, the three types of jacketed reactors are fine-grained reactors, medium-grained reactors, and coarse-grained reactors.

[0011] As a further explanation of the present invention, the fine-grained fly ash corresponds to a fine-grained reactor, the medium-grained fly ash corresponds to a medium-grained reactor, and the coarse-grained fly ash corresponds to a coarse-grained reactor.

[0012] As a further explanation of the present invention, after placing the corresponding fly ash into the fine-particle-grade reactor, the medium-particle-grade reactor and the coarse-particle-grade reactor respectively, a 10 mol / L NaOH solution is added at a solid-liquid ratio of 1:8 to carry out a staged reaction. The fine-particle reactor was set to a temperature of 110°C and the reaction time was 2.5 hours. The medium-particle size reactor was set to a temperature of 130°C and the reaction time was 3.5 hours. The coarse-grained reactor was set to 180°C, ultrasonic assistance was turned on, and the reaction was carried out for 5 hours.

[0013] As a further explanation of the present invention, the online analysis unit is specifically an ICP-OES online analyzer.

[0014] As a further explanation of the present invention, the feedback mixing unit consists of an Al sheet dissolving tank and a SiO2 powder feeding bin. Using the Al sheet dissolving tank and the SiO2 powder feeding bin, Al or Si sources are quantitatively added to the reaction liquids of the fine-particle-grade reaction vessel, the medium-particle-grade reaction vessel, and the coarse-particle-grade reaction vessel for adjustment, so that the Si / Al ratio of the mixed reaction liquid is stabilized at 1.0±0.05.

[0015] As a further explanation of the present invention, the crystallization process is carried out in a high-pressure sealed reactor at a pressure of 0.1-0.8 MPa, a crystallization temperature of 90-180°C, and a crystallization time of 2-24 hours. The reactor is equipped with an adjustable stirring device with a stirring speed of 150 rpm.

[0016] As a further explanation of the present invention, the centrifugation, washing and drying treatment of the crystallized product specifically involves separating the crystallized product by centrifugation, sending the obtained filter cake to a washing tower and washing it with deionized water until pH=7.5, and then sending it to a dryer to dry at 105°C for 3 hours.

[0017] Secondly, a method for preparing an apparatus for the staged reaction of fly ash to prepare zeolite includes the following steps: S1. After removing metal impurities, the fly ash is graded to obtain three particle sizes: fine, medium, and coarse. S2. The three particle sizes of fly ash—fine, medium, and coarse—are fed into the fine-particle reactor, medium-particle reactor, and coarse-particle reactor, respectively. NaOH solution is added, and the mixture is reacted for 2-6 hours under different temperature conditions. S3. After the reaction is completed, the silicon-to-aluminum ratio of the reaction liquid in the fine-particle-scale reactor, medium-particle-scale reactor and coarse-particle-scale reactor is detected by the online analysis unit, and Al source or Si source is added by the feedback adjustment unit to adjust it to the target value. S4. The adjusted reaction solution enters the crystallization and drying unit for crystallization treatment. After centrifugation, washing, and drying, the crystallized product is obtained as zeolite product. The crystallization temperature is controlled at 100-120℃, and the crystallization time is 4-6 hours to obtain NaA type zeolite; The crystallization temperature is controlled at 150-180℃, and the crystallization time is 12-16 hours to obtain P-type zeolite.

[0018] Compared with the prior art, the present invention has the following advantages: This invention achieves optimal reaction conditions for all fly ash particle sizes through particle size classification and differentiated reaction condition design. The conversion rate of coarse particles is increased from 60%-70% in the prior art to over 90%, while the over-reaction rate of fine particles is controlled within 5%, resulting in an overall increase in raw material utilization of 25%-30%.

[0019] This invention achieves precise control of the silicon-to-aluminum ratio through an online analysis unit and a feedback adjustment unit, enabling the directional synthesis of NaA or P-type zeolites with a product crystallinity ≥85% and a specific surface area ≥300m². 2 / g, ammonia nitrogen adsorption capacity ≥120mg / g, and performance stability is improved by 40% compared with traditional methods. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of this application, not all of them. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] like Figure 1 As shown, the present invention provides a technical solution: an apparatus for the staged reaction of fly ash to prepare zeolite, comprising: The grading and screening unit, specifically an air classifier, classifies the fly ash after removing metal impurities. The grading and screening unit separates the fly ash into fine particles ≤45μm, medium particles 45~90μm, and coarse particles >90μm based on particle size, with a grading efficiency ≥95%. A multi-stage reaction unit, wherein the multi-stage reaction unit consists of at least three jacketed reactors with independent temperature control corresponding to fine-grained, medium-grained, and coarse-grained fly ash; The three types of jacketed reactors are fine-particle reactor, medium-particle reactor, and coarse-particle reactor; The fine-grained fly ash corresponds to the fine-grained reactor, the medium-grained fly ash corresponds to the medium-grained reactor, and the coarse-grained fly ash corresponds to the coarse-grained reactor. After the corresponding fly ash is placed in the fine-grained reactor, the medium-grained reactor, and the coarse-grained reactor, a 10mol / L NaOH solution is added at a solid-liquid ratio of 1:8 to carry out the staged reaction. The fine-particle reactor was set to 110°C and reacted for 2.5 hours. The medium-particle size reactor was set to 130°C and reacted for 3.5 hours. The coarse-grained reactor was set to 180°C, ultrasonic assistance was turned on, and the reaction was carried out for 5 hours.

[0023] The online analysis unit, specifically an ICP-OES online analyzer, detects Si in the reaction solution in real time. 4+ Al 3+ Data on ion concentration and calculation of the silicon-to-aluminum ratio; A feedback adjustment unit receives the result data from the online analysis unit and automatically adds an aluminum source or a silicon source based on the result data; The feedback mixing unit consists of an Al sheet dissolving tank and a SiO2 powder feeding bin. Using the Al sheet dissolving tank and the SiO2 powder feeding bin, Al or Si sources are quantitatively added to the reaction liquids of the fine-particle-grade reaction vessel, the medium-particle-grade reaction vessel, and the coarse-particle-grade reaction vessel for adjustment, so that the Si / Al ratio of the mixed reaction liquid is stabilized at 1.0±0.05. The crystallization and drying unit performs crystallization treatment on the reaction solution after being prepared by the feedback preparation unit. The crystallization treatment is carried out in a high-pressure sealed reactor at a pressure of 0.1-0.8 MPa, a crystallization temperature of 90-180°C, and a crystallization time of 2-24 hours. It is equipped with an adjustable stirring device with a stirring speed of 150 rpm. The crystallized product is centrifuged, washed, and then dried. Specifically, the crystallized product is separated by a centrifuge, and the resulting filter cake is sent to a washing tower and washed with deionized water until pH=7.5. Then it is sent to a dryer and dried at 105°C for 3 hours.

[0024] The control system is connected to the graded screening unit, the multi-stage reaction unit, the online analysis unit, the feedback mixing unit, and the crystallization drying unit to complete the control operation.

[0025] The preparation method of the above-mentioned apparatus for the staged reaction of fly ash to prepare zeolite includes the following steps: S1. After removing metal impurities, the fly ash is graded to obtain three particle sizes: fine, medium, and coarse. S2. The three particle sizes of fly ash—fine, medium, and coarse—are fed into the fine-particle reactor, medium-particle reactor, and coarse-particle reactor, respectively. NaOH solution is added, and the mixture is reacted for 2-6 hours under different temperature conditions. S3. After the reaction is completed, the silicon-to-aluminum ratio of the reaction liquid in the fine-particle-scale reactor, medium-particle-scale reactor and coarse-particle-scale reactor is detected by the online analysis unit, and Al source or Si source is added by the feedback adjustment unit to adjust it to the target value. S4. The adjusted reaction solution enters the crystallization and drying unit for crystallization treatment. After centrifugation, washing, and drying, the crystallized product is obtained as zeolite product. The crystallization treatment temperature was controlled at 100-120℃, and the crystallization time was 4-6 hours to obtain NaA type zeolite with a crystallinity of 88.6% and a specific surface area of ​​325 m². 2 / g, with an ammonia nitrogen adsorption capacity of 128mg / g, all indicators are superior to similar products prepared by traditional methods.

[0026] The crystallization treatment temperature is controlled at 150-180℃, and the crystallization time is 12-16 hours to obtain P-type zeolite with a crystallinity of 87.5% and a specific surface area of ​​332 m². 2 / g, ammonia nitrogen adsorption capacity of 122mg / g, and performance stability improved by 40% compared with traditional methods.

[0027] Moreover, the targeted reaction condition design reduces NaOH usage by 30%-40%, shortens the total reaction time by 40%-50%, reduces waste liquid discharge by 60%, and reduces energy consumption per ton of product by about 200 kWh, meeting the requirements of low-carbon development. The fully automated control of the process reduces labor costs, and it can handle fly ash from different power plants and with different compositions. It is suitable for Si / Al fluctuations of 1.5-3.5, and the zeolite product type can be flexibly adjusted according to market demand, possessing broad industrial application prospects.

[0028] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0029] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0030] The directional terms "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," or "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0031] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for the staged reaction of fly ash to prepare zeolite, characterized in that, include: The grading and screening unit separates fly ash into fine particles ≤45μm, medium particles 45~90μm, and coarse particles >90μm based on particle size, with a grading efficiency ≥95%. A multi-stage reaction unit, wherein the multi-stage reaction unit consists of at least three jacketed reactors with independent temperature control corresponding to fine-grained, medium-grained, and coarse-grained fly ash; The online analysis unit detects Si in the reaction solution in real time. 4+ Al 3+ Data on ion concentration and calculation of the silicon-to-aluminum ratio; A feedback adjustment unit receives the result data from the online analysis unit and automatically adds an aluminum source or a silicon source based on the result data; The crystallization and drying unit performs crystallization treatment on the reaction solution prepared by the feedback mixing unit, and the crystallized product is dried after centrifugation and washing. The control system is connected to the graded screening unit, the multi-stage reaction unit, the online analysis unit, the feedback mixing unit, and the crystallization drying unit to complete the control operation.

2. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 1, characterized in that, The grading and screening unit is specifically an air classifier, which is used to classify fly ash after removing metal impurities.

3. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 1, characterized in that, The three types of jacketed reactors are fine-particle reactor, medium-particle reactor, and coarse-particle reactor.

4. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 3, characterized in that, The fine-grained fly ash corresponds to the fine-grained reactor, the medium-grained fly ash corresponds to the medium-grained reactor, and the coarse-grained fly ash corresponds to the coarse-grained reactor.

5. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 4, characterized in that, After placing the corresponding fly ash into the fine-particle-scale reactor, medium-particle-scale reactor, and coarse-particle-scale reactor respectively, 10 mol / L NaOH solution was added at a solid-liquid ratio of 1:8 to carry out the staged reaction. The fine-particle reactor was set to 110°C and reacted for 2.5 hours. The medium-particle size reactor was set to 130°C and reacted for 3.5 hours. The coarse-grained reactor was set to 180°C, ultrasonic assistance was turned on, and the reaction was carried out for 5 hours.

6. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 1, characterized in that, The online analysis unit is specifically an ICP-OES online analyzer.

7. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 6, characterized in that, The feedback mixing unit consists of an Al sheet dissolving tank and a SiO2 powder feeding bin. Using the Al sheet dissolving tank and the SiO2 powder feeding bin, Al or Si sources are quantitatively added to the reaction liquids of the fine-particle-grade reaction vessel, the medium-particle-grade reaction vessel, and the coarse-particle-grade reaction vessel for adjustment, so that the Si / Al ratio of the mixed reaction liquid is stabilized at 1.0±0.

05.

8. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 1, characterized in that, The crystallization process is carried out in a high-pressure sealed reactor at a pressure of 0.1-0.8 MPa, a crystallization temperature of 90-180°C, and a crystallization time of 2-24 hours. The reactor is equipped with an adjustable stirring device with a stirring speed of 150 rpm.

9. The apparatus for staged reaction of fly ash to prepare zeolite according to claim 1, characterized in that, The specific process of centrifugation, washing and drying of the crystallized product is as follows: the crystallized product is separated by centrifuge, the resulting filter cake is sent to a washing tower and washed with deionized water until pH=7.5, and then sent to a dryer and dried at 105°C for 3 hours.

10. A method for preparing an apparatus for the staged reaction of fly ash to prepare zeolite according to any one of claims 1-9, characterized in that, Includes the following steps: S1. After removing metal impurities, the fly ash is graded to obtain three particle sizes: fine, medium, and coarse. S2. The three particle sizes of fly ash—fine, medium, and coarse—are fed into the fine-particle reactor, medium-particle reactor, and coarse-particle reactor, respectively. NaOH solution is added, and the mixture is reacted for 2-6 hours under different temperature conditions. S3. After the reaction is completed, the silicon-to-aluminum ratio of the reaction liquid in the fine-particle-scale reactor, medium-particle-scale reactor and coarse-particle-scale reactor is detected by the online analysis unit, and Al source or Si source is added by the feedback adjustment unit to adjust it to the target value. S4. The adjusted reaction solution enters the crystallization and drying unit for crystallization treatment. After centrifugation, washing, and drying, the crystallized product is obtained as zeolite product. The crystallization temperature is controlled at 100-120℃, and crystallization is carried out for 4-6 hours to obtain NaA type zeolite; The crystallization temperature is controlled at 150-180℃, and crystallization is carried out for 12-16 hours to obtain P-type zeolite.

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