A microporous sound-absorbing ceramic made from river and lake sediment and coal-based solid waste

Abstract

The invention discloses a microporous sound-absorbing ceramic using river and lake bottom mud and coal-based solid waste as raw materials, belonging to the field of environmentally friendly materials. The raw material composition and mass percentage of the high-sound-absorbing microporous ceramic are as follows: 30% to 50% lake bottom mud; 25% to 40% coal gangue; 15% to 20% diatomaceous earth; 40% to 60% water; 1%-3% dispersant; 1%-3% gelling agent; and 3%-5% foaming agent. The preparation method comprises the following steps: drying and grinding the lake bottom mud to prepare uniform bottom mud powder with a mesh size of more than 100; mixing the bottom mud powder, coal gangue powder, and diatomaceous earth powder to prepare a mixed powder; adding water, a dispersant, and a gelling agent to the mixed powder, placing the mixed powder in a ball mill, and milling the mixed powder to obtain a uniform mixed slurry; then adding a foaming agent, stirring, and foaming the mixed slurry; then performing injection molding, vibration, and demoulding to obtain a green embryo; and finally sintering and cooling the green embryo to obtain a finished product. The sound-absorbing ceramic of the present invention is a through-hole material with high porosity, small pore size and good medium and high frequency sound absorption performance.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection materials, and in particular to a microporous sound-absorbing ceramic prepared by utilizing river and lake bottom mud and coal-based solid waste. Background Art

[0002] Noise pollution has become a global issue, listed alongside water and air pollution as one of the world's three major pollution problems. It seriously harms the human auditory system, causing fatigue and deafness. It also accelerates the aging of buildings and mechanical structures, affecting the accuracy and service life of equipment and instruments. With the rapid development of industry and transportation, noise pollution is becoming increasingly serious, especially in densely populated and economically developed large and medium-sized cities, and particularly in areas along highways and railways, making it a hot topic of concern in environmental governance.

[0003] Currently, noise pollution is primarily controlled through passive noise control, using sound absorption. Sound-absorbing materials are the most fundamental material means of controlling the quality of the acoustic environment. Proper placement of these materials can improve the indoor acoustic environment. Porous sound-absorbing materials are a widely used type of sound-absorbing material. Compared to other sound-absorbing materials, porous sound-absorbing materials offer advantages such as light weight, a wide frequency range, and excellent overall sound absorption.

[0004] Existing research on porous ceramics focuses primarily on materials, including improved preparation methods, improved performance through different microstructures, geometric parameters, and composite materials, and the impact of changes in the raw materials used to prepare porous ceramics on sound absorption. Existing porous ceramic sound-absorbing materials suffer from expensive raw materials, complex preparation processes, low porosity, and poor sound absorption, making them difficult to promote and apply on a large scale. Relatively little attention has been paid to and research has been conducted on the use of lake sediments and coal-based solid waste to prepare porous ceramics for noise control. This is particularly true when using fly ash and coal gangue to prepare porous ceramics, which are often prepared using pore-forming agents and powder stacking methods. Patent application number CN 110342956 B is a low-cost ecological ceramic material with multiple sound-absorbing structures and its preparation method. This patent uses fly ash, coal gangue, red mud, etc. as raw materials, and forms perforated plate sound-absorbing structures, micro-perforated resonant sound-absorbing structures, and thin plate resonant sound-absorbing structures through ball milling, adding surfactants and viscose pore-forming agents, and then light pressing, punching, drying, sintering, etc., thereby obtaining porous ceramics that can be used for sound absorption and noise reduction. However, the sound absorption performance of this porous ceramic is mainly reflected below 1000Hz; Patent application number CN 204079799U, 2015.01.07 is a kind of particle sound-absorbing board and its preparation method. This patent selects sound-absorbing particles with appropriate diameters. The sound-absorbing board is obtained by adding skeleton particles and mixing with a binder. The particle sound-absorbing board prepared by this patent has poor sound absorption performance. The sound absorption coefficient at the sound absorption peak of 700Hz is less than 0.3, and the half-sound absorption bandwidth of the normal incidence sound absorption coefficient is 1000Hz-1600Hz, which is a narrow sound absorption bandwidth. Patent number CN 104177119 B. A method for preparing lightweight fly ash thermal insulation porous ceramics. This patent uses fly ash as the main raw material, adds auxiliary materials, and prepares it into thermal insulation material through ball milling dispersion, water bath stirring foaming, gel curing, drying and sintering. The thermal insulation material is characterized by large pore size and closed pores, and cannot be used as a sound-absorbing material; Dai Yonggang et al. used coal gangue and fly ash from a certain area in the north as the main raw materials, bentonite and waste baking soda as auxiliary materials, and silicon carbide micropowder as a foaming agent, and prepared foamed ceramic plates by powder stacking method (Dai Yonggang, Zhang Guotao, Yang Jingqi. Preparation and performance study of coal gangue-fly ash based foamed ceramics [J]. Foshan Ceramics, 2019, 29(11): 24-28.). This study discussed the pore size, compressive strength, and preparation process of porous ceramics, but did not mention the acoustic properties of the porous ceramics. Zhang Jixiang et al. attempted to use coal gangue as the main raw material, added foaming agents and other additives, and used gel injection molding to prepare porous sound-absorbing materials with excellent high-frequency sound absorption performance (Zhang Jixiang, Liu Wei, Dong Yingge et al. Preparation of porous ceramic sound-absorbing materials using coal gangue [J] China Ceramics, 2010, 46(06): 50-51.). The factors that affect the porosity, sound absorption performance, and compressive strength of the samples were discussed. The sound absorption coefficient of the sound-absorbing ceramic reached a peak of approximately 0.7 at 2000Hz.Therefore, this field urgently needs to propose a circular solution that combines environmental noise control and solid waste disposal, reduce raw material costs, and prepare high-sound-absorbing open-pore sound-absorbing ceramics through a simple preparation process, so as to eliminate the limitations of existing technologies and achieve the effect of environmental protection and noise pollution control. Summary of the Invention

[0005] To address these issues, the present invention discloses a microporous sound-absorbing ceramic made from river and lake sediments and coal-based solid waste. This through-pore material features high porosity, tiny pores, and excellent mid- and high-frequency sound absorption. The raw materials for this high-performance open-pore sound-absorbing ceramic are low-carbon, environmentally friendly, readily available, resource-efficient, and low-cost. This addresses existing porous ceramic sound-absorbing materials, which suffer from expensive raw materials, complex preparation processes, low porosity, poor sound absorption, and difficulty in large-scale promotion and application.

[0006] The technical solution adopted by the present invention is a microporous sound-absorbing ceramic prepared using river and lake sediments and coal-based solid waste, comprising the following raw materials in percentage by mass: sediment powder: 20 to 60 parts, coal gangue: 30 to 60 parts, diatomaceous earth: 10 to 30 parts, water: 40 to 60 parts, dispersant: 0.1 wt% to 0.5 wt%, gelling agent: 0.3 wt% to 1.2 wt%, and foaming agent: 0.4 wt% to 0.7 wt%.

[0007] Furthermore, the dispersant is one or both of sodium lignin sulfonate and sodium polyacrylate. The weight of sodium lignin sulfonate is 0.1wt% to 0.3wt% of water, and the weight of sodium polyacrylate is 0.1wt% to 0.4wt% of sodium polyacrylate. Both sodium lignin sulfonate and sodium polyacrylate have dispersing effects. Their combined use has a stronger dispersing effect, requires less dosage, and provides better dispersion stability, resulting in a slurry with high solid content, good fluidity, and good dispersibility.

[0008] The sodium lignin sulfonate used in the present invention is an anionic surfactant with strong dispersing ability, suitable for dispersing solids in aqueous media, soluble in aqueous solutions of various pH values, and environmentally friendly. At the same time, the sodium polyacrylate is stable to temperature changes, has the function of fixing metal ions, and can prevent the negative effects of metal ions on products. It is a surfactant with multiple special properties and a ceramic processing aid. It plays a dispersing role, makes the slurry have lower viscosity, and can increase the fluidity of the slurry.

[0009] A method for preparing microporous sound-absorbing ceramics using river and lake bottom mud and coal-based solid waste comprises the following steps:

[0010] Step 1, raw material sludge powder;

[0011] The lake bottom mud is taken out, dried, crushed, sieved and made into dry and uniform powder;

[0012] Step 2, slurry preparation;

[0013] Mixing raw material bottom mud powder, coal gangue, and diatomaceous earth to obtain a mixed powder, mixing the mixed powder with water, adding a dispersant, and ball milling for the first time, then adding a gelling agent, and ball milling for the second time to obtain a slurry with a solid content of 40wt% to 75wt%;

[0014] Step 3, foam injection molding;

[0015] The slurry obtained in step 2 is transferred to a beaker, a foaming agent is added, and then stirred in a water bath to obtain a foamed slurry; the foamed slurry is then injected into a mold and allowed to stand for 2 to 4 hours;

[0016] Step 4, drying and sintering;

[0017] Remove the mold in step 3 to obtain a sample;

[0018] The sample is placed in an oven for drying to obtain a green body;

[0019] The green body is placed in a high-temperature sintering furnace for sintering, and then the furnace is cooled to room temperature to obtain the desired high sound-absorbing microporous ceramic.

[0020] A further improvement of the present invention is:

[0021] The drying method of the bottom mud in step 1 is to dry it at room temperature, and the particle size range of the bottom mud powder after screening is 38 to 74 microns.

[0022] In step 2, the mass ratio of the mixture of sludge powder, coal gangue, and diatomaceous earth is (2-6):(3-6):(1-3);

[0023] The weight ratio of the mixed powder to water is (2-4):(1-3).

[0024] In step 2, the dispersant is specifically sodium hexametaphosphate and sodium polyacrylate, and the weight thereof is 0.1wt% to 0.5wt% of water; the weight of sodium lignin sulfonate is 0.1wt% to 0.3wt% of water, and the weight of sodium polyacrylate salt is 0.1wt% to 0.4wt%; the weight of the gelling agent is 0.3wt% to 1.2wt% of water, and the gelling agent is specifically acrylamide.

[0025] The parameters of the first ball milling in step 2 are: ball milling at a speed of 200-400 rpm for 1 h to 2 h; the parameters of the second ball milling are: ball milling at a speed of 200-400 rpm for 2 h to 3 h.

[0026] In step 3, the foaming agent adopts the AM-MBAM system, wherein acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) are compounded in a ratio of 7:3, and the weight is 0.4wt% to 0.7wt% of the water in step 2. At this time, the foaming ability is optimal, and the obtained microporous sound-absorbing ceramic has high porosity and excellent sound absorption performance.

[0027] In step 3, the water bath temperature is 70°C to 80°C, and the stirring time is 5 to 10 minutes. The addition of water bath heating shortens the stirring time, improves the stirring efficiency, and improves the foaming effect. The parameters of the oven drying in step 4 are: oven temperature 70°C to 80°C, and drying time 6 hours to 8 hours.

[0028] In step 4, the sintering parameters of the high-temperature sintering furnace are as follows: the high-temperature sintering furnace is heated to 500°C at a rate of 10°C / min, kept at this temperature for 60min-120min, then heated to 1450°C-1650°C at a rate of 15°C / min, kept at this temperature for 1h-2h, and then cooled to room temperature.

[0029] Beneficial effects of the present invention:

[0030] 1. The present invention utilizes lake sediment and coal-based solid waste to prepare microporous sound-absorbing ceramics. Combining lake sediment disposal, coal-based solid waste treatment, and noise control, the invention provides a circular solution. Lake sediment and coal gangue are used as the main raw materials to prepare microporous sound-absorbing ceramics for use in noise control through a gel foaming injection molding process. The use of coal gangue, as one of the raw materials in the microporous sound-absorbing ceramics, effectively enhances the strength of the ceramics, making them more suitable for practical engineering applications.

[0031] 2. The present invention adopts a gel foaming method and heats the water bath during the stirring process to make the foaming more complete, shorten the stirring and foaming time, and improve the preparation efficiency; the foaming agent adopts the AM-MBAM system, in which acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) are compounded in a ratio of 7:3, which is beneficial to improving the sound absorption performance of the microporous ceramic.

[0032] 3. The microporous sound-absorbing ceramic of this patent is an open-pore material with high porosity and small pore size, so it has high sound absorption characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 , is a preparation flow chart of a microporous sound-absorbing ceramic prepared by using river and lake bottom mud and coal-based solid waste;

[0034] Figure 2 , is a microscopic pore morphology of a microporous sound-absorbing ceramic prepared using river and lake sediment and coal-based solid waste obtained in an embodiment of the preparation method of the present invention;

[0035] Figure 3, is a curve diagram of sound absorption coefficients at different frequencies of microporous sound-absorbing ceramics prepared using river and lake bottom mud and coal-based solid waste obtained in an embodiment of the preparation method of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0037] Preparation process as Figure 1 As shown, specifically:

[0038] Step 1, obtaining sediment powder;

[0039] The lake bottom mud is salvaged, dried, crushed, and passed through a 400-mesh sieve to form a dry and uniform powder;

[0040] Step 2, slurry preparation;

[0041] Weigh 40 parts of lake sediment powder, 40 parts of coal gangue, 20 parts of diatomaceous earth, and 40 parts of water, mix them, add dispersant sodium lignin sulfonate at a weight of 0.2wt% of water, and sodium polyacrylate at a weight of 0.3wt% of water; ball mill at a speed of 300rpm for 1h, then add a gelling agent, and ball mill at a speed of 300rpm for 1h to obtain a slurry; the gelling agent is specifically acrylamide, with a weight of 0.7wt% of water.

[0042] Step 3, foam injection molding;

[0043] The slurry obtained in step 2 was transferred to a beaker, and 0.5 wt% of the foaming agent acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) were added in a ratio of 7:3 based on the weight of water. The mixture was then stirred for 10 minutes in a water bath at 80°C to obtain a foaming slurry. The foaming slurry was then injected into a mold and allowed to stand for 8 hours.

[0044] Step 4, drying and sintering;

[0045] The mold in step 3 is removed to obtain a sample; the sample is placed in an oven at a temperature of 70°C and dried for 6 hours to obtain a green body; the green body is placed in a high-temperature sintering furnace, heated to 200°C at a rate of 10°C / min, kept warm for 60 minutes, then heated to 1450°C at a rate of 15°C / min, kept warm for 1 hour, and the furnace is cooled to room temperature to obtain the required microporous sound-absorbing ceramics prepared using river and lake bottom mud and coal-based solid waste.

[0046] According to the method of Example 1, high sound absorption microporous ceramic samples with a thickness of 20 mm were prepared. Figure 2 As shown, there are many tiny micropores distributed in the sample, and the pore size is evenly distributed, with the pore size concentrated between 50μm and 150μm.

[0047] like Figure 3 As shown in the figure, the noise reduction coefficient of the sample with a thickness of 20 mm reaches above 0.8 in the range of 0 to 5000 Hz, which meets the requirements for the use of sound-absorbing materials.

[0048] Example 2

[0049] Step 1, obtaining sediment powder;

[0050] The lake bottom mud is salvaged, dried, crushed, and passed through a 400-mesh sieve to form a dry and uniform powder;

[0051] Step 2, slurry preparation;

[0052] Weigh 30 parts of lake sediment powder, 40 parts of coal gangue, 30 parts of diatomaceous earth, and 50 parts of water, mix them, add dispersant sodium lignin sulfonate at a weight of 0.2wt% of water, and sodium polyacrylate at a weight of 0.4wt% of water; ball mill at a speed of 300rpm for 1h, then add a gelling agent, and ball mill at a speed of 300rpm for 2h to obtain a slurry; the gelling agent is specifically acrylamide, with a weight of 0.7wt% of water.

[0053] Step 3, foam injection molding;

[0054] The slurry obtained in step 2 was transferred to a beaker, and 0.6 wt% of acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) as foaming agents were added in a ratio of 7:3 based on the weight of water. The mixture was then stirred for 10 minutes in a water bath at 70°C to obtain a foaming slurry. The foaming slurry was then injected into a mold and allowed to stand for 10 hours.

[0055] Step 4, drying and sintering;

[0056] The mold in step 3 is removed to obtain a sample; the sample is placed in an oven at a temperature of 70°C and dried for 6 hours to obtain a green body; the green body is placed in a high-temperature sintering furnace, heated to 200°C at a rate of 10°C / min, kept warm for 60 minutes, then heated to 1450°C at a rate of 15°C / min, kept warm for 1 hour, and the furnace is cooled to room temperature to obtain the required microporous sound-absorbing ceramics prepared using river and lake bottom mud and coal-based solid waste.

[0057] According to the method of Example 2, a sample of highly sound-absorbing microporous ceramic with a thickness of 20 mm and a diameter of 30 mm was prepared. The test results showed that the noise reduction coefficient reached 0.7 in the range of 0 to 5000 Hz.

[0058] Example 3

[0059] Step 1, obtaining sediment powder;

[0060] The lake bottom mud is salvaged, dried, crushed, and passed through a 200-mesh sieve to form a dry and uniform powder;

[0061] Step 2, slurry preparation;

[0062] Weigh 50 parts of lake sediment powder, 40 parts of coal gangue, 10 parts of diatomaceous earth, and 55 parts of water, mix them, add dispersant sodium lignin sulfonate at a weight of 0.1wt% of water, and sodium polyacrylate at a weight of 0.2wt% of water; ball mill at a speed of 300rpm for 2h, then add a gelling agent, and ball mill at a speed of 300rpm for 3h to obtain a slurry; the gelling agent is specifically acrylamide, with a weight of 0.8wt% of water.

[0063] Step 3, foam injection molding;

[0064] The slurry obtained in step 2 was transferred to a beaker, and 0.7 wt% of acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) as foaming agents were added in a ratio of 7:3 based on the weight of water. The mixture was then stirred for 10 minutes in a water bath at 70°C to obtain a foaming slurry. The foaming slurry was then injected into a mold and allowed to stand for 12 hours.

[0065] Step 4, drying and sintering;

[0066] The mold in step 3 is removed to obtain a sample; the sample is placed in an oven at a temperature of 70°C and dried for 6 hours to obtain a green body; the green body is placed in a high-temperature sintering furnace, heated to 200°C at a rate of 10°C / min, kept warm for 1200 minutes, then heated to 1450°C at a rate of 15°C / min, kept warm for 1 hour, and the furnace is cooled to room temperature to obtain the required microporous sound-absorbing ceramics prepared using river and lake bottom mud and coal-based solid waste.

[0067] According to the method of Example 2, a sample of highly sound-absorbing microporous ceramic with a thickness of 20 mm and a diameter of 30 mm was prepared. The test results showed that the noise reduction coefficient reached 0.6 in the range of 0 to 5000 Hz.

[0068] Example 4

[0069] Step 1, obtaining sediment powder;

[0070] The lake bottom mud is salvaged, dried, crushed, and passed through a 200-mesh sieve to form a dry and uniform powder;

[0071] Step 2, slurry preparation;

[0072] Weigh 60 parts of lake sediment powder, 20 parts of coal gangue, 20 parts of diatomaceous earth, and 60 parts of water, mix them, add dispersant sodium lignin sulfonate at a weight of 0.1wt% of water, and sodium polyacrylate at a weight of 0.3wt% of water; ball mill at a speed of 300rpm for 1h, then add a gelling agent, and ball mill at a speed of 400rpm for 3h to obtain a slurry; the gelling agent is specifically acrylamide, with a weight of 0.5wt% of water.

[0073] Step 3, foam injection molding;

[0074] The slurry obtained in step 2 was transferred to a beaker, and 0.4 wt% of acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) as foaming agents were added in a ratio of 7:3 based on the weight of water. The mixture was then stirred for 10 minutes in a water bath at 80°C to obtain a foaming slurry. The foaming slurry was then injected into a mold and allowed to stand for 8 hours.

[0075] Step 4: Drying and sintering

[0076] The mold in step 3 is removed to obtain a sample; the sample is placed in an oven at a temperature of 70°C and dried for 6 hours to obtain a green body; the green body is placed in a high-temperature sintering furnace, heated to 200°C at a rate of 10°C / min, kept warm for 80 minutes, then heated to 1450°C at a rate of 15°C / min, kept warm for 1 hour, and the furnace is cooled to room temperature to obtain the required microporous sound-absorbing ceramics prepared using river and lake bottom mud and coal-based solid waste.

[0077] According to the method of Example 2, a sample of highly sound-absorbing microporous ceramic with a thickness of 20 mm and a diameter of 30 mm was prepared. The test results showed that the noise reduction coefficient reached 0.75 in the range of 0 to 5000 Hz.

[0078] like Figure 3 Figure 2 shows the sound absorption coefficient curves at different frequencies for the microporous sound-absorbing ceramics prepared from river and lake sediments and coal-based solid waste in the examples. Example 1 achieved a maximum sound absorption coefficient of 0.99 at a frequency of approximately 2000 Hz, Example 2 achieved a maximum sound absorption coefficient of 0.97 at approximately 1000 Hz, Example 3 achieved a maximum sound absorption coefficient of 0.98 at approximately 1800 Hz, and Example 4 achieved a maximum sound absorption coefficient of 0.89 at approximately 1200 Hz. The microporous sound-absorbing ceramics in the examples all exhibited high sound absorption properties over a wide frequency band, with Example 1 achieving the highest sound absorption performance at a frequency of 2000 Hz.

[0079] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above-mentioned embodiment, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A method for preparing microporous sound-absorbing ceramics using river and lake sediments and coal-based solid waste, characterized in that: The following steps are involved: Step 1: Raw sediment powder: Take out the lake sediment, dry it, crush it, sieve it, and make it into dry and uniform powder; Step 2: slurry preparation: mixing raw material bottom mud powder, coal gangue, and diatomaceous earth to obtain a mixed powder, mixing the mixed powder with water and adding a dispersant, ball milling for the first time, then adding a gelling agent, and ball milling for the second time to obtain a slurry with a solid content of 40wt% to 75wt%; the mass ratio of the bottom mud powder, coal gangue, and diatomaceous earth in the step 2 is (2 to 6): (3 to 6): (1 to 3); the weight ratio of the mixed powder to water is (2 to 4): (1 to 3); the dispersant in step 2 is specifically sodium hexametaphosphate and sodium polyacrylate, and the weight is 0.1wt% to 0.5wt% of water; the weight of sodium lignin sulfonate is 0.1wt% to 0.3wt% of water, and the weight of sodium polyacrylate is 0.1wt% to 0.4wt% of water; the weight of the gelling agent is 0.3wt% to 1.2wt% of water, and the gelling agent is specifically acrylamide; Step 3: Foam injection molding: transfer the slurry obtained in step 1 to a beaker, add a foaming agent, and then stir under water bath conditions to obtain a foamed slurry; then inject the foamed slurry into the mold and let it stand for 2 hours to 4 hours; the foaming agent in step 3 adopts an AM-MBAM system, wherein acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) are compounded in a ratio of 7:3, and the weight is 0.4wt% to 0.7wt% of the water in step 2; Step 4: Drying and sintering, removing the mold in step 3 to obtain a sample; placing the sample in an oven for drying to obtain a green body; placing the green body in a high-temperature sintering furnace for sintering, and then cooling the furnace to room temperature to obtain the microporous sound-absorbing ceramic prepared using river and lake bottom mud and coal-based solid waste.

2. The method for preparing microporous sound-absorbing ceramics using river and lake sediments and coal-based solid waste according to claim 1, characterized in that: The drying method of the bottom mud in step 1 is to dry it at room temperature, and the particle size range of the bottom mud powder after screening is 38 to 74 microns.

3. The method for preparing microporous sound-absorbing ceramics using river and lake sediments and coal-based solid waste according to claim 1, characterized in that: The parameters of the first ball milling in step 2 are: ball milling at a speed of 200-400 rpm for 1 h to 2 h; the parameters of the second ball milling are: ball milling at a speed of 200-400 rpm for 2 h to 3 h.

4. The method for preparing microporous sound-absorbing ceramics using river and lake sediments and coal-based solid waste according to claim 1, characterized in that: In step 5, the sintering parameters of the high-temperature sintering furnace are as follows: the high-temperature sintering furnace is heated to 500°C at a rate of 10°C / min, kept warm for 60min-120min, then heated to 1450°C-1650°C at a rate of 15°C / min, kept warm for 1h-2h, and then cooled to room temperature.

5. A microporous sound-absorbing ceramic prepared from river and lake sediments and coal-based solid waste, characterized by: The microporous sound-absorbing ceramic is prepared by using the preparation method of any one of claims 1 to 4 using river and lake bottom mud and coal-based solid waste.

Images