Enhanced ceramic filter plate and preparation process thereof

Abstract

The reinforced ceramic filter plate comprises a supporting layer, a transition layer and a surface functional layer which are sequentially arranged from bottom to top, and further comprises a metal net framework, the supporting layer, the transition layer and the surface functional layer take aluminum silicate fibers as reinforcing phases, and take silica sol, modified epoxy resin and nano kaolin as matrix phases; the content of Al2O3 in the aluminum silicate fiber is 45-55%, the content of SiO2 is 45-55%, and the diameter of the aluminum silicate fiber is 6-10 [mu] m; according to the invention, the metal net skeleton is additionally arranged to cooperate with fiber reinforcement, gradient layered structure design and low-temperature curing process, so that the preparation energy consumption is reduced, the filtering performance is improved, and the mechanical strength and impact resistance of the filter plate are further enhanced.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas purification and high-temperature gas filtration technology, specifically to an enhanced ceramic filter plate and its preparation process. Background Technology

[0002] Ceramic filter plates, due to their high temperature resistance, corrosion resistance, and high filtration accuracy, are widely used in industrial flue gas purification and chemical raw material filtration. However, existing ceramic filter plates generally suffer from problems such as difficulty in balancing strength and porosity, poor thermal shock resistance, and high sintering energy consumption. Traditional non-sintered ceramic filter plates typically have a bending strength below 30 MPa, are prone to delamination, and have a long-term operating temperature below 300℃. While sintered ceramic filter plates offer slightly improved strength, they require high-temperature sintering above 1600℃, resulting in extremely high energy consumption. Furthermore, they exhibit high flow resistance during filtration, limited PM2.5 capture efficiency, and a short service life. Additionally, ceramic filter plates are generally brittle and lack impact resistance, making them prone to breakage during installation, transportation, and use, further limiting their industrial application. Therefore, developing a high-strength, impact-resistant, low-energy-consumption, high-performance, and long-life reinforced ceramic filter plate and its preparation process has become an important research direction in the field of ceramic filtration materials. Summary of the Invention

[0003] To address the technical shortcomings of existing ceramic filter plates, such as the prominent contradiction between strength and porosity, poor thermal shock resistance, high sintering energy consumption, low filtration efficiency, high flow resistance, short service life, and insufficient impact resistance, this invention provides an enhanced ceramic filter plate and its preparation process. By adding a metal mesh skeleton in combination with fiber reinforcement, a gradient layered structure design, and a low-temperature curing process, the mechanical strength and impact resistance of the filter plate are further enhanced while reducing preparation energy consumption and improving filtration performance, thus solving many problems existing in the prior art.

[0004] This invention provides the following technical solution: An enhanced ceramic filter plate includes a support layer, a transition layer, and a surface functional layer arranged sequentially from bottom to top, and a metal mesh skeleton. The metal mesh skeleton is embedded inside the ceramic filter plate or covers the surface of the ceramic filter plate. The support layer, transition layer, and surface functional layer all use aluminosilicate fibers as the reinforcing phase and silica sol, modified epoxy resin, and nano-kaolin as the matrix phase. The aluminosilicate fibers contain 45-55% Al2O3 and 45-55% SiO2, and have a diameter of 6-10 μm. The support layer uses chopped fibers with a fiber volume fraction of 10 vol%. The transition layer uses continuous fibers with a fiber volume fraction of 20 vol%. The surface functional layer uses chopped fibers with a fiber length of 150-300 μm and a fiber volume fraction of 15 vol.

[0005] Furthermore, the metal mesh skeleton is made of a high-temperature and corrosion-resistant metal, specifically stainless steel, titanium alloy, or nickel-based alloy; the wire diameter of the metal mesh skeleton is 0.1-0.3 mm, and the aperture is 1-5 mm.

[0006] Furthermore, when the metal mesh skeleton is embedded inside the ceramic filter plate, it is embedded in the support layer or transition layer, and the embedding depth is 1 / 3 to 1 / 2 of the total thickness of the ceramic filter plate.

[0007] Furthermore, when the metal mesh skeleton is covered on the surface of the ceramic filter plate, it is covered on the outside of the surface functional layer or the outside of the support layer, the covering thickness is the same as the thickness of the metal mesh skeleton, and the metal mesh skeleton is tightly attached to the corresponding surface layer.

[0008] Furthermore, the surface of the aluminum silicate fiber is provided with a nano-SiO2 coating layer with a thickness of 100-200nm, which is formed by impregnation and drying of a nano-silica sol solution with a SiO2 content of 30% and a pH of 9.5.

[0009] Furthermore, the thickness of the support layer is 5-6 mm, the thickness of the transition layer is 3-4 mm, the thickness of the surface functional layer is 2-3 mm, and the thickness of the metal mesh skeleton is 0.2-0.5 mm.

[0010] Furthermore, the matrix phase, by weight percentage, comprises 40wt% deionized water, 30wt% silica sol with 30% SiO2 content, 15wt% modified epoxy resin with 40% solid content, 3wt% nano-kaolin with D50=200nm, 0.5wt% dispersant, and 0.3wt% defoamer; the dispersant is ammonium polyacrylate.

[0011] A process for preparing an enhanced ceramic filter plate includes the following steps: Step 1: Raw material pretreatment, the aluminum silicate fiber is subjected to plasma surface activation treatment and nano-coating treatment in sequence, and the metal mesh skeleton is subjected to rust removal and corrosion resistance pretreatment. Step 2: Slurry preparation. Prepare matrix slurries separately, and add different types and contents of pretreated fibers to the matrix slurries to prepare support layer slurries, transition layer slurries and surface functional layer slurries accordingly. Step 3: Gradient molding process. A three-channel molding mold is used. First, the pre-treated metal mesh skeleton is fixed in the mold at a preset position. Then, the corresponding slurry is injected in sequence for vacuum suction molding. The molding parameters of each layer are controlled to achieve the overall structure molding and obtain a wet blank. The layer injection sequence is to inject the corresponding slurry in the order of support layer, transition layer and surface functional layer. When the metal mesh skeleton is fixed in the preset position of the support layer or transition layer, it is fixed in the corresponding layer molding area in the mold before the corresponding layer slurry is injected. Step 4: Post-curing treatment. The wet blank is subjected to pre-curing and main curing treatment in sequence, followed by silica sol impregnation and heat treatment to obtain the reinforced ceramic filter plate.

[0012] Furthermore, in step 1, the pretreatment process of the metal mesh skeleton is as follows: first, the surface rust is removed by sanding with sandpaper, then it is immersed in a corrosion-resistant coating solution for 15-20 minutes, and dried at 80°C for 30 minutes to form a corrosion-resistant coating with a thickness of 50-100nm; the plasma surface activation treatment uses argon plasma with a processing power of 300W, a processing time of 5min, and a gas flow rate of 5L / min; the nano-coating treatment involves immersing the activated fibers in a nano-silica sol solution for 30 minutes and drying at 100°C for 1 hour.

[0013] Further, in step 3, the vacuum degree of the vacuum suction molding is controlled at -0.08MPa; the injection flow rate of the support layer slurry is 0.8L / min, and the molding time is 10min; the injection flow rate of the transition layer slurry is 0.3L / min, and the molding time is 5min; the injection flow rate of the surface functional layer slurry is 0.5L / min, and the molding time is 8min; the moisture content of the wet blank after molding is controlled at 45-50%; in step 4, the pre-curing conditions are: temperature 80℃, time 2 hours, humidity 40%RH, and heating rate 1℃ / min; the main curing is sequentially: 100℃ for 1 hour, 120℃ for 2 hours, and 150℃ for 1 hour, with a heating rate of 2℃ / min; the post-treatment is: impregnation with 20% silica sol for 10 minutes, followed by heat treatment at 150℃ for 1 hour and holding at 180℃ for 30 minutes to remove residual organic matter.

[0014] The present invention has the following beneficial technical effects: 1. The filter plate of this invention has a bending strength of up to 55-60MPa, which is more than 80% higher than that of traditional non-sintered products. The interlayer peel strength is increased to 2.2kN / m. With the reinforcement of the metal mesh skeleton, the impact resistance is increased by more than 3 times. It completely solves the problems of easy delamination and brittleness of traditional products, and the structural stability is significantly enhanced. 2. The invention optimizes thermal performance and weather resistance: the long-term operating temperature is increased to 550℃, far exceeding that of traditional organic adhesive products, and the corrosion rate in 10% HCl is <0.1% after 30 days. The wear resistance is more than twice that of conventional products. After corrosion-resistant treatment, the metal mesh skeleton works together with the ceramic matrix to withstand harsh working conditions, making it more adaptable. 3. The present invention has excellent and stable filtration performance: PM2.5 collection efficiency reaches 99.3%, which is 15 percentage points higher than traditional products; initial pressure drop is only 175Pa, which is more than 40% lower; dust holding capacity reaches 800g / m²; dust cleaning cycle is extended by 50%; the metal mesh skeleton has a reasonable pore size design, which does not affect the filtration flow efficiency, and achieves high-efficiency and low-resistance filtration. 4. The present invention has outstanding energy-saving and consumption-reducing effects: the curing temperature is ≤150℃, which saves 80% energy compared with the traditional sintering process (>1600℃), reduces CO2 emissions by 85%, meets the requirements of carbon neutrality and development, and significantly reduces the preparation cost; 5. The service life of this invention is significantly extended: under normal working conditions, the service life can reach 3-4 years, which is twice that of traditional products. The metal mesh frame effectively reduces damage during installation and transportation as well as structural damage during use, reduces the frequency of replacement, further reduces the cost of use, and has more significant industrial application value. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an enhanced ceramic filter plate structure according to the present invention.

[0016] The attached figures are labeled as follows: 1. Support layer; 2. Transition layer; 3. Surface functional layer; 4. Metal mesh skeleton; Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example See Figure 1 An enhanced ceramic filter plate includes a support layer 1, a transition layer 2, and a surface functional layer 3 arranged sequentially from bottom to top, and a metal mesh skeleton 4. The metal mesh skeleton 4 is embedded inside the ceramic filter plate or covers the surface of the ceramic filter plate. The support layer 1, transition layer 2, and surface functional layer 3 all use aluminosilicate fibers as the reinforcing phase and silica sol, modified epoxy resin, and nano-kaolin as the matrix phase. The aluminosilicate fibers contain 45-55% Al2O3 and 45-55% SiO2, and have a diameter of 6-10 μm. The support layer 1 uses chopped fibers with a fiber volume fraction of 10 vol%. The transition layer 2 uses continuous fibers with a fiber volume fraction of 20 vol%. The surface functional layer 3 uses chopped fibers with a fiber length of 150-300 μm and a fiber volume fraction of 15 vol%.

[0018] Preferably, the metal mesh skeleton 4 is made of high-temperature and corrosion-resistant metal, specifically stainless steel, titanium alloy, or nickel-based alloy; the wire diameter of the metal mesh skeleton 4 is 0.1-0.3 mm, and the aperture is 1-5 mm.

[0019] When the metal mesh skeleton 4 is embedded inside the ceramic filter plate, it is embedded in the support layer 1 or the transition layer 2, and the embedding depth is 1 / 3 to 1 / 2 of the total thickness of the ceramic filter plate.

[0020] When the metal mesh skeleton 4 is covered on the surface of the ceramic filter plate, it is covered on the outside of the surface functional layer 3 or the outside of the support layer 1, and the covering thickness is the same as the thickness of the metal mesh skeleton 4, and the metal mesh skeleton 4 is tightly attached to the corresponding surface layer.

[0021] The surface of the aluminum silicate fiber is provided with a nano-SiO2 coating layer with a thickness of 100-200nm, which is formed by impregnation and drying of a nano-silica sol solution with a SiO2 content of 30% and pH=9.5.

[0022] Preferably, the thickness of the support layer 1 is 5-6 mm, the thickness of the transition layer 2 is 3-4 mm, the thickness of the surface functional layer 3 is 2-3 mm, and the thickness of the metal mesh skeleton 4 is 0.2-0.5 mm.

[0023] The matrix phase, by weight percentage, comprises 40wt% deionized water, 30wt% silica sol with 30% SiO2 content, 15wt% modified epoxy resin with 40% solid content, 3wt% nano-kaolin with D50=200nm, 0.5wt% dispersant, and 0.3wt% defoamer; the dispersant is ammonium polyacrylate.

[0024] A process for preparing an enhanced ceramic filter plate includes the following steps: 1. Raw material preparation Prepare aluminum silicate fiber (50% Al2O3, 50% SiO2, 8μm diameter), silica sol with 30% SiO2 content, modified epoxy resin with 40% solid content, nano-kaolin with D50=200nm, ammonium polyacrylate dispersant, defoamer, deionized water, stainless steel metal mesh skeleton 4 (wire diameter 0.2mm, pore size 3mm, thickness 0.3mm), as well as plasma treatment equipment, three-channel molding die, water ring vacuum pump, feeding system and other equipment.

[0025] 2. Raw material pretreatment (1) Pretreatment of aluminum silicate fiber: Place aluminum silicate fiber in a plasma treatment device, introduce argon gas and adjust the parameters to power 300W and gas flow rate 5L / min, and treat for 5min to complete surface activation; prepare a nano-silica sol solution with SiO2 content of 30% and pH=9.5, immerse the activated fiber in it for 30 minutes, take it out and dry it in an environment of 100℃ for 1 hour to form a nano-SiO2 coating layer with a thickness of about 150nm.

[0026] (2) Pretreatment of metal mesh skeleton 4: Use fine sandpaper to polish the rust on the surface of stainless steel metal mesh skeleton 4 until the surface is smooth. Then immerse it in the corrosion resistant coating solution for 18 minutes, take it out and dry it in an 80℃ environment for 30 minutes to form a corrosion resistant coating with a thickness of 80nm.

[0027] 3. Slurry preparation Weigh the raw materials by weight percentage: 40wt% deionized water, 30wt% silica sol with 30% SiO2 content, 15wt% modified epoxy resin, 3wt% nano-kaolin, 0.5wt% ammonium polyacrylate, and 0.3wt% defoamer. Mix them evenly to obtain the matrix slurry. Use a paddle mixer to stir at 200rpm for 30min. Add pretreated fibers to the matrix slurry: add 10vol% short chopped fibers to prepare support layer 1 slurry, add 20vol% continuous fibers to prepare transition layer 2 slurry, and add 15vol% short chopped fibers with a length of 200μm to prepare surface functional layer 3 slurry. After stirring evenly, store them separately in the feeding system.

[0028] 4. Gradient molding Mold and skeleton positioning: Install and fix the three-channel forming mold. According to the preset requirement that the metal mesh skeleton 4 needs to be fixed in the middle of the transition layer 2, put the pre-treated stainless steel metal mesh skeleton 4 into the forming area of ​​the transition layer 2 in the mold. Fix it by positioning protrusion to ensure that it is about 1.5mm away from the upper and lower end faces of the transition layer 2. Vacuum casting: Start the water ring vacuum pump to stabilize the vacuum level inside the mold at -0.08MPa. First, inject the support layer 1 slurry at a flow rate of 0.8L / min and cast for 10 minutes. Then, inject the transition layer 2 slurry at a flow rate of 0.3L / min and cast for 5 minutes. During the injection process, the slurry evenly coats the metal mesh skeleton 4. Finally, inject the surface functional layer 3 slurry at a flow rate of 0.5L / min and cast for 8 minutes. Wet blank inspection: After molding, the moisture content of the wet blank is tested to ensure it is around 48% to guarantee the curing effect.

[0029] 5. Post-curing treatment The wet blank is transferred to a curing environment and heated to 80°C at a rate of 1°C / min. It is then kept at this temperature for 2 hours under 40%RH conditions to complete pre-curing. The temperature is then increased to 100°C and kept at 1 hour, 120°C and kept at 2 hours, and 150°C and kept at 1 hour at a rate of 2°C / min to complete the main curing. A 20% silica sol is prepared, and the cured blank is immersed in it for 10 minutes. After removal, it is first heat-treated at 150°C for 1 hour, and then heated to 180°C and kept at 30 minutes to remove residual organic matter, finally obtaining the finished reinforced ceramic filter plate.

[0030] The finished filter plate underwent performance testing, and its bending strength was 58MPa, interlaminar peel strength was 2.2kN / m, and its impact resistance was 3.2 times higher than that of the filter plate without the added metal mesh skeleton 4. The long-term operating temperature was 550℃, the PM2.5 collection efficiency was 99.3%, the initial pressure drop was 175Pa, the corrosion rate in 10% HCl was 0.08% after 30 days, and the service life under normal working conditions could reach 3.5 years. All performance characteristics were superior to those of traditional ceramic filter plates and filter plates without the added metal mesh skeleton 4, effectively meeting the needs of harsh working conditions.

[0031] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A reinforced ceramic filter plate, characterized in that, The filter includes a support layer (1), a transition layer (2), and a surface functional layer (3) arranged sequentially from bottom to top, and also includes a metal mesh skeleton (4); the metal mesh skeleton (4) is embedded inside the ceramic filter plate or covers the surface of the ceramic filter plate; the support layer (1), the transition layer (2), and the surface functional layer (3) all use aluminum silicate fiber as the reinforcing phase and silica sol, modified epoxy resin, and nano-kaolin as the matrix phase; the aluminum silicate fiber has an Al2O3 content of 45-55%, an SiO2 content of 45-55%, and a diameter of 6-10μm; the support layer (1) uses short-cut fibers with a fiber volume fraction of 10 vol%; the transition layer (2) uses continuous fibers with a fiber volume fraction of 20 vol%; the surface functional layer (3) uses short-cut fibers with a fiber length of 150-300μm and a fiber volume fraction of 15 vol%.

2. The reinforced ceramic filter plate according to claim 1, characterized in that, The metal mesh skeleton (4) is made of high temperature and corrosion resistant metal, and is made of stainless steel, titanium alloy or nickel-based alloy; the wire diameter of the metal mesh skeleton (4) is 0.1-0.3mm and the aperture is 1-5mm.

3. The reinforced ceramic filter plate according to claim 1, characterized in that, When the metal mesh skeleton (4) is embedded inside the ceramic filter plate, it is embedded in the support layer (1) or the transition layer (2) respectively, and the embedding depth is 1 / 3-1 / 2 of the total thickness of the ceramic filter plate.

4. The reinforced ceramic filter plate according to claim 1, characterized in that, When the metal mesh skeleton (4) is covered on the surface of the ceramic filter plate, it is covered on the outside of the surface functional layer (3) or the outside of the support layer (1), and the covering thickness is consistent with the thickness of the metal mesh skeleton (4), and the metal mesh skeleton (4) is tightly attached to the corresponding surface layer.

5. The reinforced ceramic filter plate according to claim 1, characterized in that, The surface of the aluminum silicate fiber is provided with a nano-SiO2 coating layer with a thickness of 100-200nm, which is formed by impregnation and drying of a nano-silica sol solution with a SiO2 content of 30% and pH=9.

5.

6. The reinforced ceramic filter plate according to claim 1, characterized in that, The thickness of the support layer (1) is 5-6 mm, the thickness of the transition layer (2) is 3-4 mm, the thickness of the surface functional layer (3) is 2-3 mm, and the thickness of the metal mesh skeleton (4) is 0.2-0.5 mm.

7. The reinforced ceramic filter plate according to claim 1, characterized in that, The matrix phase, by weight percentage, comprises 40wt% deionized water, 30wt% silica sol with 30% SiO2 content, 15wt% modified epoxy resin with 40% solid content, 3wt% nano-kaolin with D50=200nm, 0.5wt% dispersant, and 0.3wt% defoamer; the dispersant is ammonium polyacrylate.

8. A preparation process for preparing an enhanced ceramic filter plate as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Raw material pretreatment, plasma surface activation treatment and nano-coating treatment are performed on aluminum silicate fibers in sequence, and rust removal and corrosion resistance pretreatment are performed on metal mesh skeleton (4); Step 2: Slurry preparation. Prepare matrix slurry separately, and add different types and contents of pretreated fibers to the matrix slurry to prepare support layer (1) slurry, transition layer (2) slurry and surface functional layer (3) slurry accordingly. Step 3: Gradient molding process, using a three-channel molding mold, first fix the pre-treated metal mesh skeleton (4) in the mold according to the preset position, then inject the corresponding slurry in the order of layer sequence for vacuum suction molding, control the molding parameters of each layer to achieve the overall structure molding, and obtain a wet blank; the layer sequence injection is to inject the corresponding slurry in the order of support layer (1), transition layer (2), surface functional layer (3). When the metal mesh skeleton (4) is fixed in the preset position of support layer (1) or transition layer (2), it is fixed in the corresponding layer molding area in the mold before the corresponding layer slurry is injected; Step 4: Post-curing treatment. The wet blank is subjected to pre-curing and main curing treatment in sequence, followed by silica sol impregnation and heat treatment to obtain the reinforced ceramic filter plate.

9. The preparation process according to claim 8, characterized in that, In step 1, the pretreatment process of the metal mesh skeleton (4) is as follows: first, the surface rust is removed by sanding with sandpaper, then it is immersed in a corrosion-resistant coating solution for 15-20 minutes, and dried at 80°C for 30 minutes to form a corrosion-resistant coating with a thickness of 50-100nm; the plasma surface activation treatment uses argon plasma with a processing power of 300W, a processing time of 5min, and a gas flow rate of 5L / min; the nano-coating treatment is to immerse the activated fiber in a nano-silica sol solution for 30 minutes and dry it at 100°C for 1 hour.

10. The preparation process according to claim 8, characterized in that, In step 3, the vacuum degree of the vacuum suction filtration molding is controlled at -0.08MPa; the slurry injection flow rate of the support layer (1) is 0.8L / min, and the molding time is 10min; the slurry injection flow rate of the transition layer (2) is 0.3L / min, and the molding time is 5min; the slurry injection flow rate of the surface functional layer (3) is 0.5L / min, and the molding time is 8min; the moisture content of the wet blank after molding is controlled at 45-50%; in step 4, the pre-curing conditions are 80℃ temperature, 2 hours time, 40%RH humidity, and 1℃ / min heating rate; the main curing is 100℃ heat treatment for 1h, 120℃ heat treatment for 2h, and 150℃ heat treatment for 1h, with a heating rate of 2℃ / min; the post-treatment is impregnation with 20% silica sol for 10 minutes, followed by heat treatment at 150℃ for 1 hour and heat treatment at 180℃ for 30 minutes to remove residual organic matter.

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