Conical diffuser combined sound-absorbing material for building and preparation method of conical diffuser combined sound-absorbing material

Abstract

The invention relates to a building sound-absorbing material combined with a conical diffuser and a preparation method of the building sound-absorbing material, in particular to the technical field of building sound-absorbing materials.The building sound-absorbing material structurally comprises a first outer protective plate, a second outer protective plate and a sound-absorbing part, and the conical diffuser is formed between the top end of the sound-absorbing part and the first outer protective plate; the sound-absorbing part comprises a plurality of circular-ring-shaped fins which are concentrically arranged by taking the center of the outer protective plate II as the circle center; the conical diffuser is formed by filling sound-absorbing blocks between the adjacent circular-ring-shaped fins and between the outermost circular-ring-shaped fin and the outer protective plate I; the sound-absorbing block is prepared from the following raw materials: a porous material, coal gangue powder, amino modified silicon dioxide aerogel powder, a gelling agent, a cross-linking agent, a binder, a foaming agent and a solvent. According to the sound-absorbing material combined with the conical diffuser design, the using amount of the sound-absorbing block material can be effectively reduced while the excellent sound-absorbing performance is guaranteed, more material cost is saved, and the material is lighter.

Description

Technical Field

[0001] The present invention belongs to the technical field of building sound-absorbing materials, and in particular relates to a building sound-absorbing material combined with a conical diffuser and a preparation method thereof. Background Art

[0002] Sound-absorbing materials are a type of material specifically designed to improve the acoustic environment of a space. When sound waves strike the surface of a sound-absorbing material, some of the sound energy is reflected, while the remainder penetrates the material and continues to propagate. Inside the material, due to the effects of air molecules and viscous resistance, the sound energy is gradually converted into heat and absorbed. This energy conversion process hinders the propagation of sound waves through the material, thereby reducing sound reflection and transmission. Common types of sound-absorbing materials used in construction include mineral wool panels, foam plastics, perforated panels, and spatial absorbers. These materials are widely used in places where noise and reverberation time must be controlled, such as concert halls, theaters, recording studios, and conference rooms.

[0003] Sound diffusers utilize the scattering properties of sound waves to disperse incident sound wave energy in multiple directions, aiming to reduce reverberation, control echoes, and improve sound clarity and uniformity. They can be configured in various shapes, such as wedge-shaped diffusers, multi-prism diffusers, conical diffusers, and inclined plane diffusers. Currently, the primary function of sound diffusers is to make the sound field more uniform and control echoes, but their application in the field of sound-absorbing and noise-reducing materials has been rarely reported. Utilizing the scattering effect of sound diffusers in combination with sound-absorbing materials to create architectural sound-absorbing materials with excellent sound absorption properties has positive research significance for promoting the development of architectural sound-absorbing materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a building sound-absorbing material combined with a conical diffuser and a preparation method thereof in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: The present invention provides a building sound-absorbing material combined with a conical diffuser, comprising an outer guard plate 1 and an outer guard plate 2 that are interlocked and installed, and a sound-absorbing portion forming a conical diffuser between the top end and the outer guard plate 1; the sound-absorbing portion comprises a plurality of annular fins concentrically arranged with the center of the outer guard plate 2 as the center of the circle; the conical diffuser is formed by filling sound-absorbing blocks between adjacent annular fins and between the outermost annular fin and the outer guard plate 1; the raw materials for preparing the sound-absorbing blocks include porous material, coal gangue powder, amino-modified silica aerogel powder, a gelling agent, a cross-linking agent, a binder, a foaming agent and a solvent.

[0006] As a further optimization solution of the present invention, the annular wing is arranged in a hollow shape with an open top.

[0007] As a further optimization solution of the present invention, the height of the annular wing is arranged to increase gradually from the center of the inner side of the second outer guard plate toward the outside.

[0008] As a further optimization scheme of the present invention, the amount of the gelling agent is 1-5wt% of the mass of the porous material, the amount of the cross-linking agent is 5-10wt% of the mass of the gelling agent, the amount of the binder is 2-8wt% of the mass of the porous material, the amount of the foaming agent is 1-5wt% of the mass of the porous material, and the amount of the solvent is 80-100wt% of the mass of the porous material.

[0009] As a further optimized solution of the present invention, the porous material is zeolite molecular sieve or honeycomb stone, and the particle size is less than 10 μm.

[0010] As a further optimized solution of the present invention, the gelling agent is any one of sodium hydroxymethyl cellulose, hydroxypropyl methyl cellulose or chitosan; and the cross-linking agent is any one of glutaraldehyde, boric acid or calcium chloride.

[0011] As a further optimized solution of the present invention, the binder is any one of polyacrylate, styrene-butadiene emulsion, polystyrene acrylate or polyurethane resin.

[0012] As a further optimized solution of the present invention, the foaming agent is ammonium bicarbonate or sodium bicarbonate.

[0013] As a further optimized solution of the present invention, the solvent is any one of methanol, ethanol or ethyl acetate.

[0014] As a second aspect of the present invention, there is also provided a method for preparing any of the above-mentioned sound-absorbing materials for construction, comprising the following steps: (1) Obtaining an integrally formed outer guard plate 1, an outer guard plate 2, and a plurality of annular fins concentrically arranged with the center of the outer guard plate 2 as the center; (2) The porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, binder, foaming agent and solvent are stirred and blended according to the formula amount to obtain a slurry, and the cross-linking agent in the formula amount is added to the slurry and continued to stir and blend to obtain a mixed paste; (3) First, obtain a mold that is consistent with the shape of the conical diffuser to be formed. Then, fill the mixed paste between adjacent annular fins and between the outermost annular fin and the mold, and then press mold it at a pressure of 30-40 MPa for 30-50 minutes. Then, remove the mold, and finally fit the outer guard plate 2 and the outer guard plate 1 together to obtain the sound-absorbing material.

[0015] The beneficial effects of the present invention are: (1) The sound-absorbing material for construction provided by the present invention incorporates a sound diffuser into the structure of the sound-absorbing material. The structure specifically includes an outer guard plate 1 and an outer guard plate 2 that are interlocked and installed, and a sound-absorbing portion that forms a conical diffuser between the top and the outer guard plate 1. The sound-absorbing material can effectively utilize the scattering effect of sound waves to disperse the sound wave energy in multiple directions, reduce sound focusing, and through the arrangement of hollow annular fins with an opening at the top, the sound wave energy can be fully absorbed by the sound-absorbing block, thereby improving the sound absorption performance of the material. In addition, the sound-absorbing material combined with the conical diffuser design can effectively reduce the amount of sound-absorbing block material while ensuring excellent sound absorption performance, thereby saving material costs and making the material lighter.

[0016] (2) The materials of the sound-absorbing block of the present invention include porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, cross-linking agent, binder, foaming agent and solvent. The addition of coal gangue powder and amino-modified silica aerogel powder not only improves the sound absorption performance of the sound-absorbing block, but also helps to improve the compressive performance of the material, thereby improving its quality and enhancing its application prospects. (3) The structure of the sound-absorbing material provided by the present invention can be installed in a modular manner, with low construction difficulty and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the sound-absorbing material for construction provided in Examples 1-5 of the present invention; Figure 2 A structural stereogram of the outer guard plate 1, outer guard plate 2, and annular winglets provided in Examples 1-5 of the present invention; Figure 3 Schematic diagram of the structure of the sound-absorbing material for construction provided in Comparative Example 1 (A), Comparative Example 2 (B) and Comparative Example 3 (C) of the present invention. DETAILED DESCRIPTION

[0018] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0019] The present invention provides a building sound-absorbing material combined with a conical diffuser, such as Figure 1-2 As shown, the structure includes an outer guard plate 1 and an outer guard plate 2 that are installed in an interlocking manner, and a sound-absorbing portion that forms a conical diffuser between the top end and the outer guard plate 1. The sound-absorbing portion includes a plurality of annular fins that are concentrically arranged with the center of the outer guard plate 2 as the center of the circle. The conical diffuser is formed by filling sound-absorbing blocks between adjacent annular fins and between the outermost annular fin and the outer guard plate 1.

[0020] In the present invention, there is no restriction on the materials of outer guard plate 1, outer guard plate 2 and the annular wing, which can be common wood materials, mineral wool materials or polyester fiber materials in this field. To ensure that outer guard plate 1 and outer guard plate 2 can be installed in a chimeric pattern, both can be formed as one piece through a mold, and modular installation can be achieved through the special chimeric structure design of outer guard plate 1 and outer guard plate 2, with low difficulty and high efficiency in later construction. The annular wing can be installed on outer guard plate 2 in a later installation manner or the annular wing can be formed as one piece with outer guard plate 2 through a special design of the mold when outer guard plate 2 is prepared. In order to optimize the sound wave propagation path, the annular wing is further configured as a hollow structure with an opening at the top, and the height of the annular wing is configured to increase from the inner center of outer guard plate 2 to the outside.

[0021] In the present invention, the raw materials for preparing the sound-absorbing block further include a porous material, coal gangue powder, amino-modified silica aerogel powder, a gelling agent, a cross-linking agent, a binder, a foaming agent, and a solvent. The porous material is a zeolite molecular sieve or honeycomb stone with a particle size of less than 10 μm, the coal gangue powder has a particle size of 20-200 mesh, and the zeolite molecular sieve can further be an MFI molecular sieve. The preparation steps of amino-modified silica aerogel powder are as follows: first, γ-aminopropyltriethoxysilane, anhydrous ethanol and water are mixed and stirred to hydrolyze the silicon source for 12 hours; then, ethyl orthosilicate is added to the hydrolyzed solution and mixed and stirred for 10 minutes, and then transferred to a gel mold and placed in a -20°C environment for gelation. The obtained wet gel is aged in anhydrous ethanol at 60°C for 24 hours; finally, the aged wet gel is directly subjected to CO2 supercritical drying to obtain amino-modified silica aerogel blocks, which can be crushed to a particle size range of 10-25μm.

[0022] The gelling agent is any one of sodium hydroxymethyl cellulose, hydroxypropyl methyl cellulose or chitosan, the cross-linking agent is any one of glutaraldehyde, boric acid or calcium chloride, the binder is any one of polyacrylate, styrene-butadiene emulsion, polystyrene acrylate or polyurethane resin, the foaming agent is ammonium bicarbonate or sodium bicarbonate, and the solvent is any one of methanol, ethanol or ethyl acetate.

[0023] Furthermore, the amount of gelling agent is 1-5wt% of the mass of the porous material, the amount of cross-linking agent is 5-10wt% of the mass of the gelling agent, the amount of binder is 2-8wt% of the mass of the porous material, the amount of foaming agent is 1-5wt% of the mass of the porous material, and the volume amount of solvent is 80-100wt% of the mass of the porous material.

[0024] Furthermore, the present invention also provides a method for preparing the above-mentioned sound-absorbing material for construction, comprising the following steps: (1) Obtaining an integrally formed outer guard plate 1, an outer guard plate 2, and a plurality of annular fins concentrically arranged with the center of the outer guard plate 2 as the center; (2) The porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, binder, foaming agent and solvent are stirred and blended according to the formula amount to obtain a slurry, and the cross-linking agent in the formula amount is added to the slurry and continued to stir and blend to obtain a mixed paste; (3) First, obtain a mold that is consistent with the shape of the conical diffuser to be formed. Then, fill the mixed paste between adjacent annular fins and between the outermost annular fin and the mold, and then press mold it at a pressure of 30-40 MPa for 30-50 minutes. Then, remove the mold, and finally fit the outer guard plate 2 and the outer guard plate 1 together to obtain the sound-absorbing material.

[0025] The beneficial effects of the present invention are described below through specific examples.

[0026] Examples 1-5 The sound-absorbing materials for construction provided in Examples 1-5 all have structures including an outer guard plate 1 and an outer guard plate 2 that are interlocked and installed with each other, and a sound-absorbing portion that forms a conical diffuser between the top and the outer guard plate 1; the sound-absorbing portion includes a plurality of annular fins that are concentrically arranged with the center of the outer guard plate 2 as the center of the circle, the annular fins are hollow with an open top, and the height is arranged to increase outward from the inner center of the outer guard plate 2, and the conical diffuser is formed by filling sound-absorbing blocks between adjacent annular fins and between the outermost annular fin and the outer guard plate 1.

[0027] The difference between Examples 1-5 is that the raw materials and proportions for preparing the sound-absorbing blocks are different, and the specific adjustments are shown in Table 1.

[0028] Table 1. Raw material selection and ratio adjustment of sound-absorbing blocks ; The preparation method of the sound-absorbing material for construction provided in Examples 1-5 comprises the following steps: (1) Obtaining an integrally formed outer guard plate 1, an outer guard plate 2, and a plurality of annular fins concentrically arranged with the center of the outer guard plate 2 as the center; (2) According to the formula amount, the porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, binder, foaming agent and solvent are stirred and blended to obtain a slurry, and the cross-linking agent in the formula amount is added to the slurry and continued to stir and blend to obtain a mixed paste; (3) First, obtain a mold that is consistent with the shape of the conical diffuser to be formed. Then, fill the mixed paste between adjacent annular fins and between the outermost annular fin and the mold, and then press mold it at a pressure of 40 MPa for 30 minutes. Then, remove the mold, and finally fit the outer guard plate 2 and the outer guard plate 1 together to obtain the sound-absorbing material.

[0029] Comparative Example 1 The sound-absorbing material for construction provided in this comparative example is Figure 3 As shown in Figure A, the structure includes outer guard plate 1, outer guard plate 2, and a sound-absorbing portion that are interlocked and mounted. The sound-absorbing portion includes multiple annular fins concentrically arranged around the center of outer guard plate 2. The annular fins are hollow with open tops. The multiple annular fins are of uniform height and one end of each contacts the inner wall of outer guard plate 1. There is no conical diffuser between the top of the sound-absorbing portion and outer guard plate 1. Sound-absorbing blocks are filled between adjacent annular fins and between the outermost annular fin and outer guard plate 1. The raw material composition and ratio used to prepare the sound-absorbing blocks are consistent with those used in Example 1.

[0030] The preparation method of the architectural sound-absorbing material of this comparative example is similar to that of Examples 1-5, and adaptive adjustments are made to the preparation methods provided in Examples 1-5 based on the structural differences of the sound-absorbing material of this comparative example.

[0031] Comparative Example 2 The building sound-absorbing material provided in this comparative example is Figure 3 As shown in Example B, the structure comprises interlocking outer panel 1, outer panel 2, and a sound-absorbing portion. The sound-absorbing portion comprises a plurality of annular fins concentrically arranged about the center of outer panel 2. The annular fins are hollow with open tops, and their height increases outward from the inner center of outer panel 2. No conical diffuser is formed between the top of the sound-absorbing portion and outer panel 1. Sound-absorbing blocks fill the spaces between adjacent annular fins and between the outermost annular fin and outer panel 1. The raw material composition and ratio of the sound-absorbing blocks in this comparative example are consistent with those used in Example 2.

[0032] The preparation method of the architectural sound-absorbing material of this comparative example is similar to that of Examples 1-5, and adaptive adjustments are made to the preparation methods provided in Examples 1-5 based on the structural differences of the sound-absorbing material of this comparative example.

[0033] Comparative Example 3 The sound-absorbing material for construction provided in this comparative example is Figure 3 As shown in Figure C, the structure includes outer panel 1 and outer panel 2 interlockingly mounted together, and a sound-absorbing portion. The sound-absorbing portion does not include annular wings, and the sound-absorbing block is directly filled into the cavity formed by the interlocking installation of outer panel 1 and outer panel 2. The raw material composition and ratio of the sound-absorbing block in this comparative example are consistent with those used in Example 4.

[0034] The preparation method of the sound-absorbing material for construction in this comparative example is similar to that of Examples 1-5, and adaptive adjustments are made according to the structural differences of the sound-absorbing material in this comparative example.

[0035] Comparative Example 4 The sound-absorbing material for construction provided in this comparative example has the same structure as Examples 1-5, but the raw material composition of the sound-absorbing blocks used therein differs from that of Examples 1-5. Comparative Example 4 provides a common commercially available sound-absorbing material block formulation: 70% by weight ceramsite; 20% by weight cement; 8% by weight fly ash; and 2% by weight inorganic foaming agent. The preparation method comprises mixing ceramsite, cement, and fly ash according to the formulated amounts to obtain a mixture, then diluting the inorganic foaming agent (hydrogen peroxide) with water and adding it to the mixture, stirring.

[0036] The preparation method of the sound-absorbing material for construction in this comparative example is similar to that of Examples 1-5.

[0037] The architectural sound-absorbing materials from Examples 1-5 and Comparative Examples 1-4 were fabricated into test specimens of uniform size. The sound absorption coefficients were tested using the standing wave tube method. The test method involved using a 100mm diameter acoustic impedance tube to measure the sound absorption performance of each specimen at different frequencies. During the test, a random standing wave was generated within the tube. The sound pressure levels at corresponding locations were measured using multiple microphone probes positioned close to the specimen. The acoustic performance of the materials was evaluated by analyzing the emission and transmission of the sound waves from the specimen surface. The sound absorption coefficients of the specimens were obtained, as shown in Table 2.

[0038] Table 2. Comparison of sound absorption coefficients ; The results in the table show that the sound-absorbing materials of Examples 1-5 of the present invention have high sound absorption coefficients and a wide frequency distribution, exhibiting excellent sound absorption at low frequencies (below 500 Hz), mid-frequency frequencies (500-200 Hz), and high frequencies (above 2000 Hz), thus having a wide range of applications. Examples 1, 2, and 4 are compared with Comparative Examples 1, 2, and 3, respectively. The difference lies in the internal structural design of the sound-absorbing materials. The sound-absorbing materials of Examples 1, 2, and 4 have conical diffusers formed within them, while the sound-absorbing materials of Comparative Examples 1 through 3 do not. The results show that while Comparative Examples 1-3 also achieve good sound absorption coefficients at low, mid-frequency, and high frequencies, and are comparable to those of Examples 1, 2, and 4, from a practical application perspective, Examples 1, 2, and 4 achieve superior sound absorption while using relatively few sound-absorbing blocks, saving raw material costs while making the sound-absorbing materials more lightweight.

[0039] Comparative Example 4, compared to Examples 1-5, replaces the sound-absorbing material structure disclosed in Examples 1-5 with a commercially available sound-absorbing material block formulation. The results show that the sound-absorbing effect is unsatisfactory, not as good as that of Examples 1-5. This demonstrates that the sound-absorbing block formulation provided by the present invention also has a positive impact on improving the sound-absorbing effect of sound-absorbing materials.

[0040] The sound absorption coefficients of the specimens in Examples 1-5 and Comparative Example 4 at different frequencies demonstrate that, for sound-absorbing materials with the same structure, the raw material selection of the sound-absorbing blocks within the structure affects the sound absorption performance of the material. To further optimize the sound absorption performance and improve the material quality, the raw material composition of the sound-absorbing blocks of the present invention was further optimized. The adjusted raw material composition of the sound-absorbing blocks is shown in Table 3.

[0041] Table 3. Raw material composition design of sound-absorbing blocks ; According to the raw material selection and proportion of each sound-absorbing block given in Table 3, the raw materials except the cross-linking agent were stirred and blended with the solvent according to the formula amount to obtain a slurry. Then, the cross-linking agent was added to the slurry in the formula amount and continued to be stirred and blended to obtain a mixed paste. The mixed paste was prepared into a cylindrical specimen using a mold. The specimen had a thickness of 15 mm and a diameter of 100 mm.

[0042] The cylindrical specimens prepared in Example 4 and Comparative Examples 5-8 were first tested for sound absorption performance (taking 500 Hz as an example). The compressive strength test was then carried out. The sound absorption test was the same as above, and the compressive strength test method was as follows: The test was conducted at room temperature using an LD26.105 universal testing machine. The machine compressed the sample at a speed of 1.5 mm / min. Three samples were selected from each group for testing, and the average value was taken as the final result. The compressive strength was calculated according to the following formula: ; Where: is the compressive stress under the specified strain, in MPa; p is the load value of the corresponding stress, in N; S is the original cross-sectional area of the specimen, in mm².

[0043] The results are shown in Table 4.

[0044] Table 4. Comparison of sound absorption coefficient and mechanical properties ; The results in the table show that the raw material composition design of the sound-absorbing block has varying degrees of influence on its sound absorption performance. Compared with Example 4, Comparative Example 5 uses silica aerogel powder instead of amine-modified silica aerogel powder. The sound absorption coefficient is significantly reduced, but the compressive strength of the specimen is not significantly changed compared with Example 4. Compared with Example 4, Comparative Example 6 does not add amine-modified silica aerogel powder but increases the amount of coal gangue powder. The sound absorption coefficient is significantly reduced, and the compressive strength of the specimen is also reduced to a certain extent. Compared with Example 4, Comparative Example 7 does not add coal gangue powder but increases the amount of amine-modified silica aerogel powder. The sound absorption coefficient and compressive strength are both reduced to a certain extent. Compared with Example 4, Comparative Example 8 uses the same amount of fly ash instead of coal gangue powder. It can be seen that the sound absorption coefficient of the specimen is significantly reduced, and the compressive strength of the specimen is also reduced to a certain extent.

[0045] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A sound-absorbing material for construction combined with a conical diffuser, characterized by: The invention relates to a sound-absorbing part comprising an outer guard plate 1 and an outer guard plate 2 which are fitted together and a conical diffuser formed between the top end and the outer guard plate 1; the sound-absorbing part comprises a plurality of annular fins which are concentrically arranged with the center of the outer guard plate 2 as the center of the circle; the conical diffuser is formed by filling sound-absorbing blocks between adjacent annular fins and between the outermost annular fin and the outer guard plate 1; the raw materials for preparing the sound-absorbing blocks include porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, cross-linking agent, adhesive, foaming agent and solvent.

2. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The annular wing is arranged in a hollow shape with an open top.

3. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The height of the annular wing is arranged to increase gradually from the center of the inner side of the second outer guard plate toward the outside.

4. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The amount of the gelling agent is 1-5wt% of the mass of the porous material, the amount of the cross-linking agent is 5-10wt% of the mass of the gelling agent, the amount of the binder is 2-8wt% of the mass of the porous material, the amount of the foaming agent is 1-5wt% of the mass of the porous material, and the amount of the solvent is 80-100wt% of the mass of the porous material.

5. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The porous material is zeolite molecular sieve or honeycomb stone, and the particle size is less than 10 μm.

6. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The gelling agent is any one of sodium hydroxymethylcellulose, hydroxypropyl methylcellulose or chitosan; and the cross-linking agent is any one of glutaraldehyde, boric acid or calcium chloride.

7. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The binder is any one of polyacrylate, styrene-butadiene emulsion, polystyrene acrylate or polyurethane resin.

8. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The foaming agent is ammonium bicarbonate or sodium bicarbonate.

9. The sound-absorbing material for construction combined with a conical diffuser according to claim 1, characterized in that: The solvent is any one of methanol, ethanol or ethyl acetate.

10. A method for preparing a sound-absorbing material for construction according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Obtaining an integrally formed outer guard plate 1, an outer guard plate 2, and a plurality of annular fins concentrically arranged with the center of the outer guard plate 2 as the center; (2) The porous material, coal gangue powder, amino-modified silica aerogel powder, gelling agent, binder, foaming agent and solvent are stirred and blended according to the formula amount to obtain a slurry, and the cross-linking agent in the formula amount is added to the slurry and continued to stir and blend to obtain a mixed paste; (3) First, obtain a mold that is consistent with the shape of the conical diffuser to be formed. Then, fill the mixed paste between adjacent annular fins and between the outermost annular fin and the mold, and then press mold it at a pressure of 30-40 MPa for 30-50 minutes. Then, remove the mold, and finally fit the outer guard plate 2 and the outer guard plate 1 together to obtain the sound-absorbing material.

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