Preparation method of small-particle-size ceramsite for sound absorption material of sound barrier

Abstract

The invention discloses a preparation method of small-particle-size ceramsite for a sound-absorbing material of a sound barrier, the small-particle-size ceramsite is obtained by adjusting the iron content, the aluminum content and the water content of a soil source and enabling a granulator to meet the conditions that 0.25 < = K1 < = 0.4 and 0.55 < = K2 < = 0.8, and an efficient and optimized solution is provided for preparation of the high-performance ceramsite sound-absorbing material of the sound barrier.

Description

Technical Field

[0001] The invention belongs to the technical field of sound-absorbing materials, and in particular relates to a method for preparing small-particle ceramsite used as sound-absorbing material for sound barriers. Technical Background

[0002] In the field of noise control for high-speed railways and urban rail transit, traditional sound barrier sound-absorbing materials mostly use fiber materials such as rock wool, and are presented in the form of a structure wrapped with hydrophobic cloth. However, such materials have many significant defects, such as the difficulty of quality control. Rock wool and hydrophobic cloth are prone to damage, powdering and collapse due to production processes or environmental factors, resulting in the loss of acoustic function of the sound barrier. Traditional cement-based sound-absorbing materials have poor acoustic performance, low sound absorption coefficient, insufficient sound insulation, and mechanical strength (compression and flexural strength) and durability that cannot meet long-term use requirements. From an environmental perspective, the production of traditional materials relies on natural resources and fails to effectively solve the problem of resource utilization of solid waste such as construction waste and sludge, which is contrary to the requirements of green and low-carbon development.

[0003] In contrast, the ceramsite firing process has been widely used in the construction field due to its light weight, high strength, high sound absorption, high seismic resistance, and high stability. Its stable properties, high sound absorption, light weight, and high pressure resistance make it promising as a sound-absorbing material for high-speed railway sound barriers. However, the existing ceramsite firing process has some limitations. On the one hand, the prepared ceramsite particle size is often large, which makes it difficult to fully exert its acoustic function when the thickness of the sound barrier is limited. On the other hand, ceramsite of different particle sizes and gradations has different absorption effects on noise of different frequencies, making it difficult to effectively reduce high-speed railway noise, thus limiting the application of ceramsite in railway sound barriers.

[0004] In summary, how to introduce expanded clay into railway sound barriers and give full play to its advantages while solving the problems of large particle size, heavy volume, limited absorption frequency range and insufficient mechanical properties of existing expanded clay has become a hot topic of current research. Summary of the Invention

[0005] In response to the problems in the prior art, the present invention provides a method for preparing small-particle ceramsite for sound barrier sound-absorbing materials, which solves the limitation that ceramsite is difficult to apply to sound barriers, and obtains small-particle ceramsite for sound barrier sound-absorbing materials and a preparation method thereof.

[0006] In a first aspect, the present invention provides a method for preparing small-sized ceramsite for use as a sound barrier and sound-absorbing material, comprising the following steps:

[0007] S1: Detect and classify the soil components, and then adjust the iron content of the classified soil to 5%-8% and the aluminum content to 1%-19%;

[0008] S2: Mix the soil source and adjust the moisture content of the mixed soil source to 20%-30%, make the soil source into a precursor adobe with a particle size of 0.4-4.75mm, wherein the sludge mass accounts for less than 30%, and add the precursor adobe into a pelletizer to prepare adobe pellets, wherein the pelletizer meets 0.25≤K1≤0.4,

[0009]

[0010] 0.55≤K2≤0.8, where the disk diameter is d, in meters, and the angle between the disk axis and the plumb line is The speed of the pelletizer is V, in rad / s, and the feeding speed is Q (m 3 / h);

[0011] S3: calcining the adobe particles to obtain small-size ceramsite.

[0012] As a further preferred solution, in step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein, 1.5≤d≤3, 23°≤φ≤38°, 0.3≤v≤0.9, 5≤Q≤15.

[0013] As a further preferred solution, in step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein, 2≤d<3, 25°≤φ≤35°, 0.4≤v≤0.9, 8≤Q≤15.

[0014] As a further solution, the method for detecting the soil source in step S1 is not limited in principle, including but not limited to any one or more of chemical analysis and spectral analysis.

[0015] As a further solution, in step S1, the soil source is not limited in principle, and technicians can select available soil sources, including but not limited to any one or more of construction waste, clay, sludge, shale, and slag.

[0016] As a further solution, in step S2, the step of adjusting the moisture content of the mixed soil source is: adjusting the moisture content of the classified soil sources respectively, and then mixing the soil sources with different moisture contents so that the moisture content of the mixed soil source is maintained between 20% and 30%.

[0017] Specifically, in this plan, according to different types of soil, the moisture content will be adjusted separately:

[0018] Among them, the moisture content of clay is adjusted to 18%-22%;

[0019] The sludge moisture content is adjusted to 28-32%;

[0020] The moisture content of other types of soil except clay and sludge is adjusted to 3% or less. The other types of soil include but are not limited to construction waste, shale, slag and one or more other soils.

[0021] As a further solution, in step S1, the method for adjusting the moisture content of the classified soil source is not limited in principle. Technicians can choose different methods to adjust the moisture content of the soil source according to needs. The adjustment methods include but are not limited to any one or more methods such as watering, drying, kiln heat recovery drying, etc.

[0022] As a further solution, in step S1, the method for adjusting the iron / aluminum content of the classified soil source is to add iron / aluminum compounds or low iron / aluminum content soil of the corresponding type of classified soil into the classified soil source.

[0023] As some preferred cases, the iron content of the classified soil source is adjusted to 5%-8%, and the aluminum content is adjusted to 10%-18%.

[0024] As a further solution, the iron / aluminum-containing compound refers to any one or more of iron / aluminum oxides and iron / aluminates.

[0025] As a further solution, in step S2, before preparing the adobe pellets by the granulator, the step of preparing the precursor adobe is as follows: preparing according to different soil sources, when the soil source contains only clay, crushing the clay, then extruding it into pellets, and screening out particles with a particle size of 0.4-4.75 mm to obtain the precursor adobe;

[0026] When the soil source contains other types of soil, the clay is crushed, then mixed with the other types of soil, extruded into granules, and sieved to obtain particles with a particle size of 0.4-4.75 mm to obtain a precursor adobe;

[0027] The particles that do not meet the requirements after screening are re-extruded into particles and screened.

[0028] As a further solution, the method of crushing the clay is not limited in principle, and technicians can choose a corresponding method to crush it, such as using a vertical soil granulator to crush the clay.

[0029] As a further solution, the method of extruding the mixed soil source into granules is not limited in principle, and technicians can select different methods and extrusion equipment to prepare granules according to needs.

[0030] As a further solution, the mass proportion of sludge in the precursor adobe is less than or equal to 25%.

[0031] As a further solution, the calcination temperature in step S3 is selected from 950° C. to 1300° C., and the calcination time is greater than 60 minutes.

[0032] As some preferred cases, the calcination temperature in step S3 is selected from 1000° C. to 1200° C., and the calcination time is selected from 80 to 180 min.

[0033] In the second aspect, the present invention provides a small-size ceramsite prepared by the above-mentioned small-size ceramsite preparation method, with a particle size of 0.6 to 5 mm and a bulk density of less than or equal to 600 g / m 3 .

[0034] In a third aspect, the present invention provides a small-particle ceramsite sound baffle, comprising small-particle ceramsite.

[0035] As a further solution, the thickness of the sound-absorbing board prepared from the small-particle ceramsite in the small-particle ceramsite sound baffle is greater than 45 mm;

[0036] As a further solution, the small-particle expanded clay sound barrier has a noise absorption coefficient greater than 0.3 at 125 Hz and a noise absorption coefficient greater than 0.6 at 125 Hz.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] This solution achieves precise control of the particle size of lightweight, small-sized ceramsite and significantly improves its sound absorption performance by precisely controlling the iron, aluminum, and moisture content of the soil source, combined with the optimization of the pelletizer process parameters. Specifically, controlling the soil source iron content to 5% to 8% and the aluminum content to 1% to 19% can enhance the binding force and compressive strength of the adobe particles, avoid particle breakage and adhesion problems, and optimize the bulk density and overall performance of the ceramsite. Controlling the soil source moisture content to 20% to 30% effectively prevents crushing and sticking during the pelletizing process, ensuring the quality and particle size stability of the ceramsite after calcination. In addition, through multi-parameter coupling optimization (K1≤0.4, 0.55≤K2≤0.8), the synergistic optimization of the pelletizer process parameters and the soil source physical properties is achieved, resulting in ceramsite with good particle size gradation and excellent sound absorption performance, with sound absorption coefficients greater than 0.3 and 0.6 for noise in the 125Hz and 250Hz frequency bands, respectively. Ultimately, this solution significantly broadens the application scope of expanded clay in sound baffles, solves the problems of difficult-to-control particle size and limited sound absorption performance in traditional preparation methods, and provides an efficient and optimized solution for the development of high-performance expanded clay sound baffles with broad application prospects. DETAILED DESCRIPTION

[0039] For ease of understanding, the present invention will be described in more detail below, and examples of the present invention are given, but the scope of the present invention is not limited thereby.

[0040] The following is a description of terms or words, and unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0041] Unless otherwise specified, the moisture content, iron content and aluminum content mentioned in the present invention refer to mass content.

[0042] The present invention provides a method for preparing small-size ceramsite for use as a sound barrier and sound-absorbing material, comprising the following steps:

[0043] S1: Detect and classify the soil components, and then adjust the soil to have an iron content of 5% to 8% and an aluminum content of 1% to 19% after classification;

[0044] S2: Mix the soil source and adjust the moisture content of the mixed soil source to 20%-30%, and make the soil source into a precursor adobe with a particle size of 0.4-4.75 mm, wherein the sludge mass accounts for less than 30%, and add the precursor adobe into the pelletizer to prepare adobe pellets.

[0045] Among them, the granulator meets

[0046] 0.25≤K1≤0.4,

[0047]

[0048] 0.55≤K2≤0.8, where the disk diameter is d, in meters, and the angle between the disk axis and the plumb line is The speed of the pelletizer is V, in rad / s, and the feeding speed is Q (m 3 / h);

[0049] S3: calcining the adobe particles to obtain small-size ceramsite.

[0050] The frequency range of ceramsite sound absorption is closely related to its particle size. By controlling the particle size of ceramsite, on the one hand, it helps to increase the density of ceramsite when preparing sound barriers and exert the sound absorption ability of ceramsite. On the other hand, it also helps to optimize the sound absorption range of ceramsite and broaden the application of ceramsite in sound barriers. However, it is not easy to control the particle size of ceramsite during the firing process. During the firing process, the particle size of ceramsite is often affected by many factors such as the moisture content of the soil source, the metal content in the soil source, the granulation speed, the feeding speed, the diameter of the granulator and even the calcination conditions. In this scheme, the iron content and aluminum content of the classified soil source are controlled. Since the iron element in the soil can be used as a natural binder, the cohesion and compressive strength of the adobe particles are improved. The synergistic aluminum element can improve the expansion performance and shear capacity of the soil. By adjusting the iron content of the classified soil source to 5% to 8% and the aluminum content to 1% to 19%, the iron and aluminum elements in the soil source are controlled, so that the iron content and aluminum content in the precursor adobe can effectively optimize the binding force between soil particles, avoid the particles from being broken due to mechanical stress (such as pelletizer disc friction, centrifugal force), and also avoid the situation of adhering to the inside of the pelletizer, thereby effectively regulating the size of small-particle ceramsite in conjunction with the pelletizer parameters. In addition, the control of the iron content and aluminum content is also helpful to optimize the bulk density of small-particle ceramsite, thereby further optimizing the comprehensive performance of small-particle ceramsite; at the same time, this scheme also regulates the moisture content in the mixed soil source, by controlling the mixed The moisture content of the soil source after combination is 20%-30%. This scheme helps to avoid the prepared precursor adobe from being crushed or sticky in the pelletizer, and at the same time, it cooperates with the pelletizer parameters to control the particle size of small-particle ceramsite; at the same time, it avoids sticking into agglomerates or affecting the weight of small-particle ceramsite during the calcination process, thereby affecting the quality of small-particle ceramsite; after regulating the moisture content of the soil source and the iron content and aluminum content, this scheme comprehensively considers various parameters for preparing adobe particles, including the disc diameter, the angle between the disc axis and the plumb line direction, the pelletizer speed and the feeding speed. In a large number of experiments, the researchers found that the disc diameter will affect the material distribution; the angle between the disc axis and the plumb line direction will affect the material movement trajectory, and the pelletizer speed can represent the centrifugal force. The relationship between gravity and the feed speed is to regulate the balance between the two. The feeding speed will affect the nucleation density of the precursor adobe. In formulas K1 and K2, this scheme comprehensively considers the interaction of the above factors. Through multi-parameter coupling constraints, the coordinated optimization of the pelletizer process parameters and the soil source properties (such as iron content, aluminum content, and moisture content) is achieved. When 0.25≤K1≤0.4 and 0.55≤K2≤0.8, the small-sized ceramsite prepared by this scheme has a good particle size gradation and has good absorption capacity for noise in different frequency bands such as 125Hz and 250Hz (when used for sound baffles with a thickness greater than 45mm, the noise absorption coefficient of 125Hz is greater than 0.3, and the noise absorption coefficient of 125Hz is greater than 0.6).

[0051] As some preferred cases, in step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein, 1.5≤d≤3, 23°≤φ≤38°, 0.3≤v≤0.9, 5≤Q≤15.

[0052] As some preferred cases, in step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein, 2≤d<3, 25°≤φ≤35°, 0.4≤v≤0.9, 8≤Q≤15.

[0053] As some cases, the method for detecting the soil source in step S1 is not limited in principle, including but not limited to any one or more of chemical analysis and spectral analysis.

[0054] As some examples, the chemical analysis method is selected from any one or more of a potentiometric method, a potassium dichromate oxidation method, and a heavy metal detection method.

[0055] As some examples, the spectral analysis method is selected from any one or more of near-infrared spectroscopy and X-ray fluorescence spectroscopy.

[0056] As some cases, in step S1, the soil source is not limited in principle, and technicians can select available soil sources, including but not limited to any one or more of construction waste soil, clay, sludge, shale, and slag.

[0057] As some examples, in step S2, the step of adjusting the moisture content of the mixed soil source is: adjusting the moisture content of the classified soil sources respectively, and then mixing the soil sources with different moisture contents so that the moisture content of the mixed soil source is maintained between 20% and 30%.

[0058] Specifically, in this plan, according to different types of soil, the moisture content will be adjusted separately:

[0059] Among them, the moisture content of clay is adjusted to 18%-22%;

[0060] The sludge moisture content is adjusted to 28-32%;

[0061] The moisture content of other types of soil except clay and sludge is adjusted to 3% or less. The other types of soil include but are not limited to construction waste, shale, slag and one or more other soils.

[0062] As some cases, in step S1, the method for adjusting the moisture content of the classified soil source is not limited in principle. Technical personnel can choose different methods to adjust the moisture content of the soil source according to needs. The adjustment methods include but are not limited to any one or more methods such as watering, drying, kiln heat recovery drying, etc.

[0063] As some cases, in step S1, the method for adjusting the iron / aluminum content of the classified soil source is to add iron / aluminum compounds to the classified soil source or to add low iron / aluminum content soil of the corresponding type of soil after classification. The low iron content soil source here refers to a soil source with an iron content of less than 5%, and the low aluminum content soil source refers to a soil source with an aluminum content of less than 15%.

[0064] As some preferred cases, the iron content of the soil source after adjustment and classification is 5% to 8%, and the aluminum content is 1% to 19%.

[0065] As some examples, the iron / aluminum-containing compound refers to any one or more of iron / aluminum oxides and iron / aluminates.

[0066] As some examples, the iron and aluminum oxides refer to oxides of different valence states containing only iron, aluminum and oxygen elements, including any one or more of ferrous oxide, ferric oxide, ferroferric oxide, ferric dioxide, ferric oxide and aluminum oxide.

[0067] As some examples, the ferrites and aluminates refer to oxides containing iron and other metals, including any one or more of calcium ferrite, sodium ferrite, potassium ferrite, lithium ferrite, magnesium ferrite, aluminum ferrite, zinc ferrite, barium ferrite, manganese ferrite, copper ferrite, and magnesium aluminate.

[0068] As some examples, in step S2, before preparing adobe pellets by a granulator, the steps of preparing a precursor adobe are as follows: preparing according to different soil sources, when the soil source contains only clay, crushing the clay, then extruding it into pellets, and screening out particles with a particle size of 0.4-4.75 mm to obtain a precursor adobe;

[0069] When the soil source contains other types of soil, the clay is crushed, then mixed with the other types of soil, extruded into granules, and sieved to obtain particles with a particle size of 0.4-4.75 mm to obtain a precursor adobe;

[0070] The particles that do not meet the requirements after screening are re-extruded into particles and screened.

[0071] As some examples, the method of crushing clay is not limited in principle, and technicians can choose a corresponding method to crush it, such as using a vertical soil granulator to crush the clay.

[0072] As some examples, the method of extruding the mixed soil source into granules is not limited in principle, and technicians can choose different methods and extrusion equipment to prepare granules according to needs.

[0073] As some examples, the sludge mass proportion in the precursor adobe is less than or equal to 25%, which helps to regulate the proportion of organic matter by controlling the sludge, thereby optimizing the internal pores of small-particle ceramsite and improving the sound absorption performance and compressive resistance of small-particle ceramsite.

[0074] As some examples, the calcination temperature in step S3 is selected from 950° C. to 1300° C., and the calcination time is greater than 60 minutes.

[0075] As some preferred cases, the calcination temperature in step S3 is selected from 1000° C. to 1200° C., and the calcination time is selected from 80 to 180 min, which helps to further improve the pore uniformity of the small-particle ceramsite, thereby improving the sound absorption performance of the small-particle ceramsite.

[0076] In the second aspect, the present invention provides a small-size ceramsite prepared by the above-mentioned small-size ceramsite preparation method, with a particle size of 0.6 to 5 mm and a bulk density of less than or equal to 600 g / m 3 .

[0077] In a third aspect, the present invention provides a small-particle ceramsite sound baffle, comprising small-particle ceramsite.

[0078] As a further solution, the thickness of the sound-absorbing board prepared from the small-particle ceramsite in the small-particle ceramsite sound baffle is greater than 45 mm;

[0079] As a further solution, the small-particle expanded clay sound barrier has a noise absorption coefficient greater than 0.3 at 125 Hz and a noise absorption coefficient greater than 0.6 at 125 Hz.

[0080] The following will be a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application and do not represent all possible embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0081] The chemical raw materials involved in the following examples and comparative examples are all prior art and are commercially available. The experimental devices, test devices, etc. involved in the following examples and comparative examples are all conventional devices in the art and are not particularly limited.

[0082] Example 1

[0083] S1: By detecting the soil source components, the soil is divided into clay, sludge, shale, and slag. The clay, sludge, shale, and slag are then aired to adjust the moisture content of the clay to 20%; the moisture content of the sludge to 30%; and the moisture content of the shale and slag to 2%. Ferric oxide, aluminum oxide, or their compounds are added to the clay, sludge, shale, and slag, respectively, and mixed evenly to adjust the iron content of the clay, sludge, shale, and slag to approximately 6% and the aluminum content to approximately 14%.

[0084] S4: Clay was crushed using a vertical soil granulator and mixed with sludge, shale, and slag, wherein the sludge accounted for 20% of the total mixed soil mass and the mixed soil had a moisture content of 25%. Pellets were prepared using a double-roll granulator and then sieved through a 4.75 mm aperture sieve to obtain a precursor adobe with a particle size of 0.4-4.75 mm. The precursor adobe was added to a disc granulator for granulation, wherein the disc diameter was 2.5 m, the angle between the disc axis and the plumb line was 30°, the granulator speed was 0.628 rad / s, and the feed speed was 10 m 3 / h;

[0085] S5: The soil pellets granulated by the disc machine are sent to the rotary kiln and calcined at 1100°C for 60 minutes to obtain small-size ceramsite.

[0086] Example 2

[0087] The synthesis method and preparation steps are the same as those in Example 1, except that the diameter of the disc is 2 m.

[0088] Example 3

[0089] The synthesis method and preparation steps are the same as those in Example 1, except that the diameter of the disc is 3 m.

[0090] Example 4

[0091] The synthesis method and preparation steps are the same as those in Example 1, except that the angle between the axis of the disk and the plumb line is 23°.

[0092] Example 5

[0093] The synthesis method and preparation steps are the same as those in Example 1, except that the angle between the axis of the disk and the plumb line is 38°.

[0094] Example 6

[0095] The synthesis method and preparation steps are the same as those in Example 1, except that the granulator speed is 0.3 rad / s.

[0096] Example 7

[0097] The synthesis method and preparation steps are the same as those in Example 1, except that the granulator speed is 0.9 rad / s.

[0098] Example 8

[0099] The synthesis method and preparation steps are the same as in Example 1, except that the feeding speed is 5m 3 / h.

[0100] Example 9

[0101] The synthesis method and preparation steps are the same as in Example 1, except that the feeding speed is 15m 3 / h.

[0102] Example 10

[0103] The synthesis method and preparation steps are the same as those in Example 1, except that the mass proportion of sludge is 30%.

[0104] Example 11

[0105] The synthesis method and preparation steps are the same as those in Example 1, except that the calcination temperature is 1000° C. and the calcination time is 40 min.

[0106] Comparative Example 1

[0107] The synthesis method and preparation steps are the same as those in Example 1, except that the moisture content of the clay is 70% and the moisture content of the mixed soil is 45%.

[0108] Comparative Example 2

[0109] The synthesis method and preparation steps are the same as those in Example 1, except that the moisture content of the sludge is 50% and the moisture content of the mixed soil is 47%.

[0110] Comparative Example 3

[0111] The synthesis method and preparation steps are the same as those in Example 1, except that the iron content is 1% and the aluminum content is 10%.

[0112] Comparative Example 4

[0113] The synthesis method and preparation steps are the same as those in Example 1, except that the iron content is 15% and the aluminum content is 25%.

[0114] Comparative Example 5

[0115] The synthesis method and preparation steps are the same as those in Example 1, except that the particle size of the precursor adobe is 5-10 mm.

[0116] Comparative Example 6

[0117] The synthesis method and preparation steps are the same as those in Example 1, except that the mass proportion of silt in the precursor adobe particles is 50%.

[0118] Comparative Example 7

[0119] The synthesis method and preparation steps are the same as those in Example 1, except that the diameter of the disc is 2.5 m, the angle between the disc axis and the plumb line is 23°, the granulator speed is 0.4 rad / s, and the feeding speed is 6 m 3 / h, K1 is 0.23, K2 is 0.78.

[0120] Comparative Example 8

[0121] The synthesis method and preparation steps are the same as those in Example 1, except that the diameter of the disc is 2.5 m, the angle between the disc axis and the plumb line is 23°, the granulator speed is 0.4 rad / s, and the feeding speed is 6 m 3 / h, K1 is 0.19, K2 is 0.85.

[0122] Test Method

[0123] Ceramic aggregate was mixed with water, cement and latex powder in a ratio of 6:1:0.15 to prepare a 50 mm thick ceramic aggregate sound-absorbing board, which was installed in the ceramic aggregate metal sound barrier structure with the air layer thickness of 54.5 mm behind it. The sound absorption coefficients at 125 Hz and 250 Hz were measured according to the standard "Measurement of Sound Absorption in Acoustic Reverberation Chambers" (GB / T20247-2006).

[0124] The test results are shown in Table 1

[0125] Table 1

[0126]

[0127]

[0128]

[0129] It can be observed from Examples 1-11 and Comparative Examples 1-8 that Example 1-11 exhibits better comprehensive sound absorption capabilities at 125 Hz and 250 Hz than Comparative Examples 1-8, indicating that the preparation method proposed in this scheme can effectively absorb sound waves in different frequency bands in railway noise, thereby broadening the application of expanded clay in railway sound baffles.

[0130] First, it can be observed from Example 1 and Comparative Examples 1-4 that when the moisture content or iron / aluminum content in the comparative examples does not meet the requirement that the soil source moisture content after mixing is 20%-30% (the clay moisture content is 18-22%, the sludge moisture content is 28-32%, and the remaining soil source moisture content is less than 2%), the soil source iron content is 5% to 8%, and the aluminum content is 1%-19%, Comparative Examples 1-4 all exhibit a comprehensive sound absorption capacity far lower than that of Example 1. This may be because when the moisture content of any one of the soil sources is higher than the set moisture content (the clay moisture content is 18-22%, the sludge moisture content is 28-32%, and the remaining soil source moisture content is less than 4-2%) (Comparative Examples 1 and 2), it is impossible to cooperate with the granulator to successfully prepare small-particle ceramsite, nor is it possible to control the particle size of the small-particle ceramsite. Therefore, the average particle size of Comparative Examples 1 and 2 is significantly worse than that of Example 1, and the sound absorption capacity is also worse than that of Example 1. At the same time, Comparative Examples 3-4 that do not meet the iron / aluminum ratio may affect the bonding ability of the soil and the mechanical properties of the particles, thereby affecting the performance of small-particle ceramsite. Therefore, Comparative Examples 3-4 exhibit weaker sound absorption performance and worse bulk density.

[0131] In Example 1 and Comparative Example 5, it can be observed that when the particle size of the precursor adobe is 5-10 mm, the average particle size of Comparative Example 5 is greatly affected, and the sound absorption capacity is also significantly weaker than that of Example 1. This may be because the 0.4-4.75 mm precursor adobe serves as the basis of the adobe particles, and can better respond to the process parameters of the pelletizer in the subsequent pelletizing process, thereby achieving precise control of the particle size of small-particle ceramsite. When the particle size of the precursor adobe is 5-10 mm, the conditions of the pelletizer will not be able to achieve effective control of the precursor adobe, thereby affecting the performance of Comparative Example 5.

[0132] Sludge usually contains a large amount of organic matter. When the content exceeds 30%, a large amount of gas will be released during the calcination process, thereby affecting the pores and surface glaze layer of small-particle ceramsite. Therefore, it is necessary to control the mass proportion of the sludge. It can be observed from Example 1 and Comparative Example 6 that when the mass proportion of the sludge is 50%, the average particle size and comprehensive sound absorption capacity of Comparative Example 6 are greatly affected. Therefore, in the raw materials for preparing small-particle ceramsite, the mass proportion of the sludge should be controlled to be less than 30%.

[0133] On the basis of the above conditions, it can be observed from Example 1 and Comparative Examples 7-8 that even if the moisture content, iron content, aluminum content, silt mass ratio, and precursor adobe particle size in the soil source all meet the requirements, when any one of the conditions of K1 and K2 cannot be met, Comparative Examples 7-8 still cannot obtain the ideal small-particle ceramsite. This is because the parameters affecting the particle size of small-particle ceramsite are very complex. Only when the above conditions are combined with each other can the ideal results be obtained. In Comparative Examples 7-8, K1 and K2 cannot be met, so Comparative Examples 7-8 cannot simultaneously achieve absorption of 125Hz and 250Hz.

[0134] In Examples 1-9, the present scheme further optimizes the parameters in K1 and K2. It can be observed that in Examples 1-3, as the disc diameter gradually increases, the sound absorption coefficient of the small-particle ceramsite at 250 Hz gradually increases. In Examples 1, 4, and 5, the increase in the angle φ between the disc axis and the plumb line direction is accompanied by an increase in the 125 Hz sound absorption coefficient. The increase in the granulator speed is also accompanied by an enhancement of the 125 Hz sound absorption capacity (Examples 1, 6, and 7). The increase in the feed speed Q can also bring about the optimization of the 125 Hz sound absorption capacity (Examples 1, 8, and 9). After comprehensively considering the sound absorption performance of the small-particle ceramsite at 125 Hz and 250 Hz, from Examples 1-9, the present scheme preferably satisfies the following conditions: 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein 2≤d<3, 25°≤φ≤35°, 0.4≤v≤0.9, and 8≤Q≤15.

[0135] In Example 10, this solution further optimizes the mass proportion of sludge in the precursor adobe. It can be observed from Examples 1 and 10 that Example 1 exhibits better sound absorption capacity than Example 10. This may be because when the mass proportion of sludge in the precursor adobe is less than 25%, it helps to further optimize the internal pore structure of small-particle ceramsite and improve the sound absorption performance of small-particle ceramsite.

[0136] The effect of calcination temperature on the performance of small-particle ceramsite is discussed in Examples 1 and 11. When the calcination temperature is selected from 1000°C to 1200°C and the calcination time is selected from 80 to 180 minutes, Example 1 exhibits better sound absorption performance than Example 11.

[0137] The various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. Although the embodiments of the present invention have been shown and described above, it can be understood that the above-described embodiments are exemplary and cannot be understood as limitations of the present invention. Those skilled in the art can change, modify, replace and deform the above-described embodiments within the scope of the present invention. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

Claims

1. A method for preparing small-size ceramsite for sound barrier sound-absorbing materials, characterized in that: The steps include: S1: Detect and classify the soil components, and then adjust the iron content of the classified soil to 5%-8% and the aluminum content of the soil to 1%-19%; S2: Mix the soil source and adjust the moisture content of the mixed soil source to 20%-30%, make the soil source into a precursor adobe with a particle size of 0.4-4.75mm, wherein the sludge mass accounts for less than 30%, and add the precursor adobe into a pelletizer to prepare adobe pellets, wherein the pelletizer meets 0.55≤K2≤0.8, where the disk diameter is d, in meters, and the angle between the disk axis and the plumb line is The unit is degree, the granulator speed is V, the unit is rad / s, the feeding speed is Q (m 3 / h); S3: calcining the adobe particles to obtain small-size ceramsite.

2. The preparation method according to claim 1, characterized in that In step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein 1.5≤d≤3, 23°≤φ≤38°, 0.3≤v≤0.9, 5≤Q≤15; Preferably, in step S3, the granulator satisfies 0.3≤K1≤0.4, 0.6≤K2≤0.8, wherein, 2≤d<3, 25°≤φ≤35°, 0.4≤v≤0.9, 8≤Q≤15.

3. The preparation method according to claim 1, characterized in that The method for detecting the soil source in step S1 is selected from any one or more of chemical analysis and spectral analysis; In step S1, the soil source is selected from any one or more of construction waste soil, clay, sludge, shale, and slag.

4. The preparation method according to claim 1, characterized in that In step S2, the step of adjusting the moisture content of the mixed soil source comprises: adjusting the moisture content of the classified soil sources respectively, and then mixing the soil sources with different moisture contents so that the moisture content of the mixed soil sources is maintained between 20% and 30%; Preferably, the moisture content of the soil is adjusted according to the different types of soil: Adjust the clay moisture content to 18%-22%; The sludge moisture content is adjusted to 28-32%; Adjust the moisture content of other types of soil, except clay and sludge, to 3% or less. Such other types of soil include but are not limited to construction waste, shale, slag, and one or more other soils; In step S1, the method for adjusting the moisture content of the classified soil source is selected from any one or more methods such as watering, airing, kiln heat recovery drying, etc.

5. The preparation method according to claim 1, characterized in that: In step S1, the method for adjusting the iron / aluminum content of the classified soil source is to add iron / aluminum compounds or low iron / aluminum content soil of the corresponding type of soil after classification into the classified soil source; Preferably, the iron content of the classified soil source is adjusted to 5%-8%, and the aluminum content is adjusted to 10%-18%; Preferably, the iron / aluminum-containing compound refers to any one or more of iron / aluminum oxides and iron / aluminates.

6. The preparation method according to claim 1, characterized in that: In step S2, before preparing adobe pellets by a granulator, the steps of preparing a precursor adobe are as follows: preparing according to different soil sources, when the soil source contains only clay, crushing the clay, then extruding it into pellets, and screening out particles with a particle size of 0.4-4.75 mm to obtain a precursor adobe; When the soil source contains other types of soil, the clay is crushed, then mixed with the other types of soil, extruded into granules, and sieved to obtain particles with a particle size of 0.4-4.75 mm to obtain a precursor adobe; The particles that do not meet the requirements after screening are re-extruded into particles and screened.

7. The preparation method according to claim 1, characterized in that: The method of crushing clay is to use a vertical soil granulator to break up the soil into clay; Preferably, the mass proportion of sludge in the precursor adobe is less than or equal to 25%.

8. The preparation method according to claim 1, characterized in that: In the step S3, the calcination temperature in the step S3 is selected from 950° C. to 1300° C., and the calcination time is greater than 30 minutes; Preferably, the calcination temperature in step S3 is selected from 1000° C. to 1200° C., and the calcination time is selected from 50 to 100 minutes.

9. A small-particle ceramsite, characterized in that: Prepared by the method of any one of claims 1 to 8; Preferably, the particle size of the small-sized ceramsite is 0.6-5 mm, and the bulk density is less than or equal to 600 g / m 3 .

10. A small-size ceramsite sound baffle, characterized in that: The small-particle ceramsite prepared by the method according to any one of claims 1 to 8 or the small-particle ceramsite according to claim 9; Preferably, the thickness of the sound absorbing board prepared from the small-particle ceramsite in the small-particle ceramsite sound baffle is greater than 45 mm; The sound absorption coefficient of small-size ceramsite sound baffles for 125Hz noise is greater than 0.3, and the sound absorption coefficient of 125Hz noise is greater than 0.6.

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