Preparation method of foamed ceramic filter based on flocking process

Abstract

The invention relates to the technical field of foamed ceramic filters, and provides a preparation method of a foamed ceramic filter based on a flocking process, and the preparation method comprises the following steps: S1, flocking cotton velvet on a sponge to prepare a flocked sponge; s2, firstly coating the flocking sponge with the main slurry, performing air drying to obtain primary slurry sponge, then spraying the guniting slurry on the primary slurry sponge, and finally performing air drying to obtain the filter sponge, and S3, sintering the filter sponge by adopting a staged heating mode to prepare the foamed ceramic filter. According to the invention, the cotton velvet is flocked on the sponge, and then the sponge is subjected to slurry hanging and sintering operation, so that the slurry is easier to hang on the flocked sponge, the processing efficiency of the foamed ceramic filter is improved, the processing cost of the foamed ceramic filter is reduced, the thickness of the connecting ribs of the flocked sponge is uniform, and the service life of the foamed ceramic filter is prolonged. And fine holes are formed in the surface of the foamed ceramic filter, so that the through hole rate and the overall performance of the foamed ceramic filter are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic foam filters, and particularly to a preparation method of a ceramic foam filter based on a flocking process. Background Art

[0002] Ceramic foam filters are commonly used filtration devices in the casting process. Their main function is to filter impurities in molten aluminum, molten iron, and molten steel. At the same time, the molten metal is resisted when passing through the ceramic foam filter, so that the flow velocity of the molten metal is more evenly distributed across the entire filter cross-section, avoiding the disordered flow caused by the direct impact of the molten metal on the cavity or the too-fast local flow velocity.

[0003] There are various preparation methods for ceramic foam filters, including the organic foam impregnation method, the foaming method, the sol-gel method, the method of adding pore-forming agents, and the 3D printing method, etc. Among them, the organic foam impregnation method does not require complex equipment and process conditions, has high feasibility for large-scale production and laboratory research, and the energy consumption during the whole preparation process is relatively low, without the need for special extreme conditions such as high temperature and high pressure, thus reducing the production cost and improving the market competitiveness of the product.

[0004] For example, a method for preparing a multi-layer ceramic foam filter by recycling waste chromic corundum disclosed in the invention patent with the publication number of CN118993763A impregnates soft polyurethane foam in the first slurry and the second slurry in sequence, and obtains the ceramic foam filter through sintering and cooling. However, the polyurethane foam is a three-dimensional network through-hole sponge generated by first longitudinally foaming polyurethane in a long foaming tank and then introducing hydrogen and oxygen for blasting. Limited by the foaming process and the blasting process, it is very difficult to achieve uniform thickness of the sponge connecting ribs, resulting in difficult slurry hanging on the sponge and affecting the filtration performance of the ceramic foam filter. Summary of the Invention

[0005] In view of this, the present invention proposes a preparation method of a ceramic foam filter based on a flocking process, which can improve the uniformity of the sponge connecting ribs and ensure the overall performance of the ceramic foam filter.

[0006] The technical solution of the present invention is realized as follows: The present invention provides a preparation method of a foam ceramic filter based on a flocking process, including the following steps: S1, spraying flocking glue on a sponge, flocking cotton velvet onto the sponge, and obtaining a flocked sponge through air drying and cutting; S2, first coating a primary slurry on the flocked sponge, obtaining a primary slurry sponge through air drying, then spraying a spraying slurry on the primary slurry sponge and making the spraying slurry cover the primary slurry sponge, and finally obtaining the filter sponge through air drying, wherein the components of the primary slurry include magnesia-stabilized zirconia, zirconia, polyvinyl alcohol, alumina, preservative, defoaming agent, dispersant and microsilica powder, and the components of the spraying slurry include polyvinyl alcohol, monoclinic zirconia, mullite sand, alumina and microsilica powder; S3, first drying the filter sponge at a constant temperature, and then sintering the filter sponge in a stepwise heating manner to obtain a foam ceramic filter.

[0007] Based on the above technical solution, preferably, the composition of the primary slurry is 280 - 320 parts of magnesia-stabilized zirconia, 180 - 220 parts of zirconia with a mesh size of 140 - 160, 90 - 110 parts of zirconia with a mesh size of 90 - 110, 110 - 130 parts of polyvinyl alcohol, 16 - 24 parts of alumina with a mesh size of 90 - 110, 2 - 4 parts of preservative, 2 - 4 parts of defoaming agent, 4 - 8 parts of dispersant and 16 - 24 parts of microsilica powder.

[0008] More preferably, the composition of the spraying slurry is 140 - 180 parts of polyvinyl alcohol, 180 - 220 parts of monoclinic zirconia with a mesh size of 280 - 320, 25 - 35 parts of mullite sand with a mesh size of 180 - 220, 35 - 45 parts of alumina with a mesh size of 90 - 110 and 16 - 24 parts of microsilica powder.

[0009] Based on the above technical solution, preferably, the viscosity of the primary slurry is 2200 - 2400 mPa·s, and the viscosity of the spraying slurry is 80 - 120 mPa·s.

[0010] Based on the above technical solution, preferably, the difference in bulk density between the primary slurry sponge and the flocked sponge is 0.25 - 0.35 g / cm 3 .

[0011] Based on the above technical solution, preferably, in step S2, the primary slurry is coated on the flocked sponge by a roll pressing method.

[0012] Based on the above technical solution, preferably, in step S1, the dosage of the flocking glue is 40 - 60 g / cm 2 , and the length of the cotton velvet is 0.3 mm - 0.8 mm.

[0013] Based on the above technical solutions, preferably, in step S3, the drying temperature of the filter sponge is 130 - 150 °C.

[0014] Even more preferably, in step S3, the temperature range for stage heating is 0 - 1650 °C, and the sintering time is 20 - 22 h.

[0015] Based on the above technical solutions, preferably, it further includes S4, performing an appearance inspection on the foam ceramic filter and removing defective products.

[0016] The preparation method of a foam ceramic filter based on the flocking process of the present invention has the following beneficial effects compared with the prior art:

[0017] (1) By first flocking cotton velvet onto the sponge and then performing sizing and sintering operations on the sponge, not only is the sizing more likely to adhere to the flocked sponge, improving the processing efficiency of the foam ceramic filter and reducing the processing cost of the foam ceramic filter, but also the connecting ribs of the flocked sponge can be made uniform in thickness, and fine pores can be created on the surface of the foam ceramic filter, improving the through-hole rate and overall performance of the foam ceramic filter.

[0018] (2) By setting the sizing to include main sizing and spraying sizing, the uneven sizing positions of the sponge can be repaired, reducing the slag dropout rate of the foam filter. By adding monoclinic zirconia and mullite sand to the spraying sizing and adjusting the dosage of the dispersant, the processing quality and processing efficiency of the foam ceramic filter can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is the surface morphology of the sponge in the preparation method of a foam ceramic filter based on the flocking process of the present invention.

[0021] Figure 2 It is the surface morphology of the flocked sponge in the preparation method of a foam ceramic filter based on the flocking process of the present invention.

[0022] Figure 3 It is the surface morphology of the disc-shaped foam ceramic filter prepared by the preparation method of a foam ceramic filter based on the flocking process of the present invention.

[0023] Figure 4The surface morphology of the square flake foam ceramic filter prepared by the preparation method of the foam ceramic filter based on the flocking process of the present invention.

[0024] Figure 5 The surface morphology of the circular flake foam ceramic filter prepared in the prior art.

[0025] Figure 6 The surface morphology of the square flake foam ceramic filter prepared in the prior art. Specific embodiments

[0026] Next, in combination with the specific embodiments of the present invention, the technical solutions in the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0027] The foam ceramic filter is a commonly used filtering device in the casting process, mainly used to filter impurities in molten aluminum, molten iron, and molten steel, and to achieve a steady flow of the cast metal liquid. The filtering mechanism of the foam ceramic filter mainly has two methods: adsorption and physical blocking. In the field of steel casting, since the pouring temperature of the cast steel is generally between 1500-1750 °C, a filter with a higher heat resistance temperature and a larger thermal pressure resistance is required. Filters made of zirconia material are usually selected in the industry.

[0028] A preparation method of a foam ceramic filter based on the flocking process of the present invention includes the following steps:

[0029] S1, material preparation: Select a polyurethane sponge with a suitable pore size and porosity as the matrix material according to the specifications and porosity of the foam ceramic filter to be processed. The number of pores per inch of the sponge is between 10 and 100, and the porosity of the sponge is above 90%, so as to ensure that the foam ceramic filter has a high filtration efficiency and flux.

[0030] Put the sponge into an aqueous solution containing an appropriate amount of surfactant and perform ultrasonic cleaning for 15-30 min to remove impurities such as oil stains and dust on the surface of the sponge. The surfactant can be selected as sodium dodecylbenzenesulfonate, and its concentration is controlled at 0.5%-1%.

[0031] The cleaned sponge is rinsed with deionized water and then placed in an oven and dried at 60-80 °C for 2-4 h until completely dry; according to actual needs, the dried sponge is cut into appropriate sizes and shapes. During the cutting process, it is necessary to ensure that the edges of the sponge are neat to avoid damage or deformation.

[0032] Apply flocking glue on both sides of the sponge, fix the glued sponge on a mobile tooling, and let the sponge pass through the flocking window of the flocking machine. At this time, the cotton flocks are charged under the action of the high-voltage electric field of the flocking machine, and are attracted and firmly adhered to the sponge coated with flocking glue, completing the flocking process.

[0033] Dry the flocked sponge to cure the flocking glue. The drying methods include natural drying, hot air drying, infrared drying, etc. Natural drying takes a long time but has low cost; hot air drying and infrared drying are fast and efficient. The drying temperature and time are determined according to the type of flocking glue and the requirements of the product. Generally, the drying temperature is between 60 - 150 °C, and the drying time ranges from several minutes to dozens of minutes.

[0034] Stamp and cut the dried sponge to obtain a flocked sponge with a fixed size, and the size of the flocked sponge is the same as that of the foam ceramic filter to be processed.

[0035] S2, Slurry Coating: Select a suitable slurry according to the operating conditions of the foam ceramic filter to be processed, evenly coat the slurry on the flocked sponge, and use an air drying line to air-dry the flocked sponge after slurry coating to obtain a filter sponge.

[0036] S3, Sintering: First, bake the filter sponge at a constant temperature, and then sinter the filter sponge in a stepwise heating manner to cause a sintering reaction between ceramic particles to form a firm structure, thus obtaining the required foam ceramic filter.

[0037] S4, Post-treatment: Inspect the appearance of the sintered foam ceramic filter, and remove products with defects such as cracks and deformations. At the same time, performance tests can also be carried out, such as porosity, compressive strength, filtration efficiency, etc. tests, to ensure that the product quality meets the requirements. Package the qualified foam ceramic filters, and the packaging materials can be selected as plastic films, cardboard boxes, etc. to prevent damage during transportation and storage.

[0038] In this preparation method, compared with the prior art, the flocking process is added. As Figure 2 shown, cotton flocks are implanted on the connecting ribs of the flocked sponge, and the cotton flocks stand upright on the surface of the connecting ribs.

[0039] First of all, the flocking process thickens the originally thinner connecting ribs of the sponge, especially the connecting ribs located at the edge of the sponge, which can not only strengthen the overall structural strength of the foam ceramic filter, but also improve the through-hole rate and overall quality of the foam ceramic filter.

[0040] Secondly, the flocking sponge has a larger surface area, making it easier for the slurry to hang on the flocking sponge, which not only reduces the slurry's requirements for glue and aggregate particle size, effectively solving problems such as insufficient slurry hanging and high processing costs, but also makes it easier to produce thicker slurry ribs. In the use scenarios where the molten steel temperature is high and the casting time is long, the foam ceramic filter processed by this preparation method has better filtering effect and filtering strength.

[0041] Finally, due to the flocking process, the cotton wool will be numerous, and after sintering, there will be a large number of blind holes with extremely small pore sizes on the surface of the foam ceramic filter. At this time, the foam ceramic filter prepared by this process has three layers of filtering function. The first layer of filtering function is the filtering holes of the foam ceramic filter itself, which can filter impurities with larger particle sizes. The second layer of filtering function is the gaps between the materials accumulated in the filtering holes of the foam ceramic filter, which can filter impurities with smaller particle sizes. The third layer of filtering function is the blind holes on the surface of the foam ceramic filter, which can absorb impurities with extremely small particle sizes in molten steel. The mutual cooperation of the three layers of filtering functions can provide the foam ceramic filter with more reliable filtering performance.

[0042] In some embodiments, the amount of flocking glue used is 40-60 g / cm 2 The length of the cotton wool is 0.3mm -0.8mm, and the bulk density difference between the primary sponge and the flocking sponge is 0.25-0.35g / cm 3 , preferably 0.3 g / cm 3 , in order to prepare a foam ceramic filter with better performance.

[0043] In step S2, the slurry includes a main slurry and a spray slurry. When the flocking sponge is coated with the slurry, it is preferably coated with the slurry by rolling, that is, the main slurry is first coated on the roller of the roller press, and then the flocking sponge is rolled by the roller to coat the main slurry on the roller, thereby achieving the effect of coating the main slurry on the flocking sponge. The flocking sponge coated with the main slurry can be air-dried to obtain a primary slurry sponge. By coating the slurry by rolling, the amount of main slurry on the primary slurry sponge can be accurately controlled, and the consistency of each primary slurry sponge can be improved, thereby effectively improving the processing accuracy of the foam ceramic filter.

[0044] After the primary slurry sponge is prepared, the spray slurry is sprayed on the primary slurry sponge, and the spray slurry covers the primary slurry sponge. Finally, the filter sponge can be obtained by air drying, and the foam ceramic filter can be obtained by subsequent drying and sintering operations.

[0045] There are two layers of slurries on the filter sponge. Both are melted and boiled with polyvinyl alcohol and water, and then transferred to a high-speed disperser for ball milling and uniform dispersion. The viscosity of the main slurry is 2200 - 2400 mPa·s, and the viscosity of the spraying slurry is 80 - 120 mPa·s. The higher viscosity of the main slurry can better roll it onto the flocked sponge, and the lower viscosity of the spraying slurry can be sprayed on the surface of the primary slurry sponge through a nozzle. When spraying the spraying slurry on the primary slurry sponge, first spray it back and forth on both sides of the primary slurry sponge once, and then spray it rotationally on the periphery of the primary slurry sponge once to improve the spraying uniformity of the spraying slurry.

[0046] The composition of the spraying slurry is different from that of the main slurry. The composition and dosage of the main slurry are 280 - 320 parts of magnesia-stabilized zirconia, 180 - 220 parts of zirconia with a mesh size of 140 - 160, 90 - 110 parts of zirconia with a mesh size of 90 - 110, 110 - 130 parts of polyvinyl alcohol, 16 - 24 parts of alumina with a mesh size of 90 - 110, 2 - 4 parts of preservative, 2 - 4 parts of defoamer, 4 - 8 parts of dispersant, and 16 - 24 parts of microsilica powder; the composition and dosage of the spraying slurry are 140 - 180 parts of polyvinyl alcohol, 180 - 220 parts of monoclinic zirconia with a mesh size of 280 - 320, 25 - 35 parts of mullite sand with a mesh size of 180 - 220, 35 - 45 parts of alumina with a mesh size of 90 - 110, and 16 - 24 parts of microsilica powder. The preservative is such as isothiazolinone, and the defoamer is such as mineral oil defoamer.

[0047] Zirconia in the existing technology is used in the main slurry, while monoclinic zirconia is used in the spraying slurry. Monoclinic zirconia can achieve higher stability in terms of crystal form, which is convenient for spraying and will not block the nozzle; mullite sand is additionally added to the spraying slurry. Mullite sand is obtained by high-temperature sintering of kaolin and is a aluminosilicate refractory material with better heat resistance strength, which can improve the heat resistance performance and structural strength of the foam ceramic filter; alkyl sulfonate is preferably used as the dispersant in the slurry to make the viscosity lower and easier to disperse; the content of microsilica powder in the slurry is higher, which is convenient for forming obvious mullite phase transformation on the surface of the foam ceramic filter to enhance the surface strength and heat resistance temperature.

[0048] The drying temperature of the filter sponge is preferably 130 - 150 °C. Due to the addition of the flocking process, in addition to wrapping the sponge, the slurry also wraps the flocking glue and cotton floss, so a longer degumming period is required; and by introducing microsilica powder, low-temperature sintering can be achieved.

[0049] The filter sponge is sintered by means of staged heating. The sintering temperature range is 0 - 1650 °C, and the sintering time is 20 - 22 h. Specifically, the preferred sintering process parameters are as follows: maintaining at 0 °C - 130 °C for 60 min; maintaining at 130 °C - 220 °C for 120 min; maintaining at 220 °C - 550 °C for 240 min; maintaining at 550 °C - 700 °C for 180 min; maintaining at 700 °C - 900 °C for 120 min; maintaining at 900 °C - 1150 °C for 90 min; maintaining at 1150 °C - 1400 °C for 180 min; maintaining at 1400 °C - 1650 °C for 210 min. The staged heating method can enable the organic components such as polyvinyl alcohol, defoamer, dispersant, and preservative in the sponge and the slurry to separate from the filter at different sintering stages, improving the separation efficiency of the sponge and the organic components, and ensuring the color consistency and overall performance of the filter. At the same time, the staged heating method can also alleviate the volume shrinkage of the material during sintering, further reducing the cracking risk of the filter.

[0050] By improving the slurry, the sintering time can also be reduced, increasing the output while reducing the energy consumption cost. At the same time, the flocking process can improve the strength and thermal shock resistance of the foam ceramic filter, and the spraying process can increase the surface heat resistance temperature, while reducing the risk of slag dropping and reducing casting defects.

[0051] Example 1

[0052] The sponge is in a square sheet shape, with a side length of 75 mm and a thickness of 20 mm. The number of pores per inch of the sponge is 15. In the flocking process, the flocking amount of the flocked sponge is 10%. The composition and dosage of the main slurry include 300 parts of 300 - mesh magnesia - stabilized zirconia, 200 parts of 150 - mesh zirconia, 100 parts of 100 - mesh zirconia, 120 parts of polyvinyl alcohol, 20 parts of 100 - mesh alumina, 3 parts of preservative, 3 parts of defoamer, 6 parts of dispersant, and 20 parts of microsilica powder. The composition and dosage of the spraying slurry include 160 parts of polyvinyl alcohol, 200 parts of 300 - mesh monoclinic zirconia, 30 parts of 200 - mesh mullite sand, 40 parts of 100 - mesh alumina, and 20 parts of microsilica powder. The foam ceramic filter is prepared by using the preparation method of the present invention.

[0053] Comparative Example 1

[0054] Compared with Example 1, the difference in this example is that the flocking amount of the flocked sponge in the flocking process is 5%.

[0055] Comparative Example 2

[0056] Compared with Example 1, the difference in this example is that the flocking process is not carried out.

[0057] Example 2

[0058] Compared with Example 1, the difference in this example is that the number of pores per inch of the sponge is 10.

[0059] Comparative Example 3

[0060] Compared with Example 2, the difference in this example is that the flocking amount of the flocked sponge in the flocking process is 5%.

[0061] Comparative Example 4

[0062] Compared with Example 2, the difference in this example is that the flocking process is not carried out.

[0063] Example 3

[0064] Compared with Example 1, the difference in this example is that the sponge is in a round sheet shape with a diameter of 90 mm.

[0065] Comparative Example 5

[0066] Compared with Example 3, the difference in this example is that the flocking amount of the flocked sponge in the flocking process is 5%.

[0067] Comparative Example 6

[0068] Compared with Example 3, the difference in this example is that the flocking process is not carried out.

[0069] Example 4

[0070] Compared with Example 3, the difference in this example is that the number of pores per inch of the sponge is 10.

[0071] Comparative Example 7

[0072] Compared with Example 4, the difference in this example is that the flocking amount of the flocked sponge in the flocking process is 5%.

[0073] Comparative Example 8

[0074] Compared with Example 4, the difference in this example is that the flocking process is not carried out.

[0075] Experimental Example 1

[0076] Prepare 10 foam ceramic filter samples for Examples 1 - 4 and Comparative Examples 1 - 8 respectively, and observe their appearances. Examples 1 - 4, Comparative Example 1, Comparative Example 3, Comparative Example 5, and Comparative Example 7 all use the flocking process. For the foam ceramic filters prepared thereby, the foam ceramic filters prepared in Example 3 and Example 1 are respectively as Figure 3 and Figure 4 shown. Comparative Examples 2, 4, 6, and 8 do not use the flocking process. For the foam ceramic filters prepared thereby, the foam ceramic filters prepared in Comparative Example 6 and Comparative Example 2 are respectively as Figure 5 andFigure 6 As shown, through comparison, it can be seen that the slurry ribs of the foam ceramic filter prepared by the flocking process are thicker, the through holes are more uniform, and the surface is pitted and not smooth, with better structural strength and filtration performance; especially at the edge position of the foam ceramic filter, the effect is more obvious.

[0077] Experimental Example 2

[0078] For Examples 1-4 and Comparative Examples 1-8, 10 foam ceramic filter samples were prepared respectively, and the normal temperature compressive strength, normal temperature shear strength, porosity, slag loss rate of the above samples were detected respectively, and the number of thermal cycles that the foam ceramic filter could withstand at 1100 °C. The test results are shown in Table 1.

[0079] Table 1

[0080]

[0081] In Examples 1-4, the flocking amount in the flocked sponge is 10%, in Comparative Examples 1, 3, 5 and 7, the flocking amount in the flocked sponge is 5%, and in Comparative Examples 2, 4, 6 and 8, the flocking amount in the flocked sponge is 0%. As can be seen from Table 1, the normal temperature compressive strength, normal temperature shear strength, porosity, thermal shock resistance and slag loss rate of the samples prepared in Examples 1-4 are the best, the performance of the samples prepared in Comparative Examples 1, 3, 5 and 7 is weakened, and the performance of the samples prepared in Comparative Examples 2, 4, 6 and 8 is the worst. Therefore, the flocking process can significantly improve the comprehensive performance of the foam ceramic filter and ensure the effective operation of the foam ceramic filter.

[0082] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a foamed ceramic filter based on a flocking process, characterized in that, It includes the following steps: S1. Spray flocking glue on the sponge, flock cotton velvet onto the sponge, and obtain the flocked sponge after air drying and cutting; S2. First, coat the main slurry on the flocked sponge, and obtain the primary slurry sponge after air drying. Then, spray the spraying slurry on the primary slurry sponge, and make the spraying slurry cover the primary slurry sponge. Finally, obtain the filter sponge after air drying, where the components of the main slurry include magnesia-stabilized zirconia, zirconia, polyvinyl alcohol, alumina, preservative, defoaming agent, dispersant, and microsilica powder, and the components of the spraying slurry include polyvinyl alcohol, monoclinic zirconia, mullite sand, alumina, and microsilica powder; S3. First, bake the filter sponge at a constant temperature, and then sinter the filter sponge in a staged heating manner to obtain the foam ceramic filter.

2. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, wherein: The composition of the main slurry is 280 - 320 parts of magnesia-stabilized zirconia, 180 - 220 parts of zirconia with a mesh size of 140 - 160, 90 - 110 parts of zirconia with a mesh size of 90 - 110, 110 - 130 parts of polyvinyl alcohol, 16 - 24 parts of alumina with a mesh size of 90 - 110, 2 - 4 parts of preservative, 2 - 4 parts of defoaming agent, 4 - 8 parts of dispersant, and 16 - 24 parts of microsilica powder.

3. The preparation method of a foamed ceramic filter based on a flocking process according to claim 2, characterized in that: The composition of the spraying slurry is 140 - 180 parts of polyvinyl alcohol, 180 - 220 parts of monoclinic zirconia with a mesh size of 280 - 320, 25 - 35 parts of mullite sand with a mesh size of 180 - 220, 35 - 45 parts of alumina with a mesh size of 90 - 110, and 16 - 24 parts of microsilica powder.

4. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: The viscosity of the main slurry is 2200 - 2400 mPa·s, and the viscosity of the spraying slurry is 80 - 120 mPa·s.

5. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: The difference in bulk density between the primary pulp sponge and the flocked sponge is 0.25 - 0.35 g / cm 3 .

6. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: In step S2, the main slurry is coated on the flocked sponge by means of roll pressing.

7. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: In step S1, the dosage of the flocking glue is 40 - 60 g / cm 2 , and the length of the cotton floss is 0.3 mm - 0.8 mm.

8. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: In step S3, the drying temperature of the filter sponge is 130 - 150 °C.

9. The preparation method of a foamed ceramic filter based on a flocking process according to claim 8, wherein: In step S3, the temperature range of staged heating is 0 - 1650 °C, and the sintering time is 20 - 22 h.

10. The preparation method of a foamed ceramic filter based on a flocking process according to claim 1, characterized in that: It also includes S4. Conduct an appearance inspection on the foam ceramic filter and remove defective products.

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