Preparation method of green low-heat-conductivity insulating brick suitable for outer wall

Abstract

The invention relates to the technical field of building materials, in particular to a preparation method of a green low-thermal-conductivity insulating brick suitable for an outer wall, which comprises the following steps: S1, weighing industrial waste, clay, a foaming agent and reinforced fibers according to a ratio, and primarily mixing; s2, carrying out wet ball-milling treatment to obtain ball-milled slurry; s3, adding a binder and water into the ball-milled slurry, and carrying out stirring homogenization treatment to obtain homogenized slurry; s4, injecting the homogenized slurry into a mold, and molding through a compression molding process to obtain a green brick body; s5, performing low-temperature sintering treatment to obtain a sintered brick body; and S6, carrying out surface hydrophobic treatment on the sintered brick body to obtain a finished insulating brick product. According to the invention, by optimizing the raw material ratio, controlling the molding and sintering process and introducing the surface hydrophobic treatment, the coordination and unification of green raw material utilization, low thermal conductivity control and the moisture resistance of the brick body are realized.

Description

A method for preparing green low thermal conductivity insulating bricks suitable for exterior walls Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a method for preparing green, low thermal conductivity insulating bricks suitable for exterior walls. Background Technology

[0002] Currently, the continuous improvement of building energy efficiency standards has placed higher performance requirements on exterior wall insulation materials. Exterior wall insulation bricks, as a new type of building material that integrates load-bearing, insulation, and weather resistance, are widely used in green building systems. In order to improve insulation performance and reduce thermal conductivity, porous structures or foaming technology are often introduced to increase thermal resistance. At the same time, in order to ensure the mechanical properties and service life of the bricks, strength, water resistance, and durability must be taken into account. With the popularization of the concept of resource recycling, research on the preparation of green insulation bricks using industrial waste has received attention, but there is still considerable room for optimization in terms of material ratio, molding process, sintering control, and surface functional treatment.

[0003] Current thermal insulation brick manufacturing technologies often face the following key challenges: First, regarding raw material selection and proportion control, while adding waste materials is beneficial for resource utilization, improper control of mixing and ball milling processes can easily lead to uneven brick structure or disordered pore distribution, thus affecting thermal conductivity. Second, during molding and low-temperature sintering, the lack of precise parameters for controlling compaction and internal structure can easily cause cracking or warping. Third, in the hydrophobic treatment stage, high-temperature glazes or coating-type waterproofing agents are often used, but poor adhesion or blockage of the pore structure can affect thermal insulation performance. Therefore, a method for manufacturing green, low-thermal-conductivity thermal insulation bricks suitable for exterior walls is urgently needed to meet the multi-performance requirements of green exterior wall materials. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a method for preparing green low thermal conductivity insulating bricks suitable for use on exterior walls.

[0005] A method for preparing green, low thermal conductivity insulating bricks suitable for exterior walls includes the following steps:

[0006] S1: Weigh out industrial waste, clay, foaming agent and reinforcing fiber in proportion, and mix them in a preliminary manner to obtain a preliminary mixture;

[0007] S2: The preliminary mixture is subjected to wet ball milling to obtain a ball mill slurry;

[0008] S3: Add binder and water to the ball mill slurry and stir to homogenize it to obtain a homogenized slurry;

[0009] S4: The homogenized slurry is injected into the mold and formed by pressing to obtain the green brick body;

[0010] S5: Low-temperature sintering treatment is performed on the green brick body to obtain sintered brick body;

[0011] S6: Perform surface hydrophobic treatment on sintered bricks to obtain finished thermal insulation bricks.

[0012] Optionally, the industrial waste is selected from fly ash, slag, or construction waste powder; the foaming agent is sodium bicarbonate, hydrogen peroxide, or aluminum powder; and the reinforcing fiber is selected from glass fiber or ceramic fiber.

[0013] Optionally, the mass percentages of the industrial waste, clay, foaming agent, and reinforcing fiber are: industrial waste 50-74%; clay 20-30%; foaming agent 5-15%; and reinforcing fiber 1-5%.

[0014] Optionally, S1 specifically includes:

[0015] S11: Weigh industrial waste, clay, foaming agent and reinforcing fiber according to the set mass percentage, and control the feeding error of each raw material within ±1% of the target mass;

[0016] S12: First, put industrial waste and clay into a dry mixing device and premix them at a speed of 100-200 rpm for 3-5 minutes to form a bottom mixture with uniformly distributed powder.

[0017] S13: Add the foaming agent and reinforcing fiber to the bottom mixture in sequence, continue the dry mixing operation, keep the speed constant, and the mixing time is 5-8 minutes;

[0018] S14: The mixture obtained in S13 is sieved with a sieve aperture of 1.5-2.0 mm to remove agglomerates and large particulate impurities, thus obtaining a preliminary mixture.

[0019] Optionally, S2 specifically includes:

[0020] S21: Put the preliminary mixture into a ball mill jar and add deionized water to control the solid-liquid mass ratio at 1:1.2 to 1:1.6;

[0021] S22: Add zirconium oxide ball milling media to the ball mill jar, and control the ball-to-material ratio to be 1:2 to 1:3;

[0022] S23: Set the ball mill speed to 200-300 rpm and the continuous wet ball milling time to 1.5-2.5 hours;

[0023] S24: After ball milling, the slurry is filtered through a 200-mesh sieve to remove coarse particles that have not been fully ground, thus obtaining the ball-milled slurry.

[0024] Optionally, S3 specifically includes:

[0025] S31: Place the ball-milled slurry in a high-speed mixing vessel and add a water-soluble binder at 3-6% of the slurry mass, wherein the binder is polyvinyl alcohol with a molecular weight of 20,000 to 50,000;

[0026] S32: Add deionized water to control the solid content of the slurry at 45-55%;

[0027] S33: Turn on the stirring device, set the stirring speed to 400-600 rpm, and the stirring time to 15-30 minutes;

[0028] S34: After mixing, filter through a 120-mesh sieve to remove any possible lumps or impurities to obtain a homogenized slurry.

[0029] Optionally, the adhesive is polyvinyl alcohol, starch glue, or silicate cement.

[0030] Optionally, S4 specifically includes:

[0031] S41: Slowly inject the homogenized slurry into a metal mold with a breathable drainage hole, control the injection rate to be 10-20 mL / s, and the injection volume to be 95%-98% of the mold cavity volume; and let it stand for 1-3 minutes.

[0032] S42: After grouting is completed, send the mold into the hydraulic pressing equipment, set the pressing pressure to 10-20MPa, and the holding time to 30-90 seconds;

[0033] S43: After pressing is completed, the green body formed in the mold is demolded and transferred to a drying tray to obtain the green brick body.

[0034] Optionally, S5 specifically includes:

[0035] S51: Place the green bricks obtained in S4 into an electric heating sintering furnace, set the heating rate to 2-4℃ / min, raise the temperature from room temperature to 300-350℃, and keep the temperature constant for 20-40 minutes to remove residual moisture and volatile components inside the bricks.

[0036] S52: Continue to raise the temperature at a rate of 3-5℃ / min to the low-temperature sintering temperature of 650-750℃, and maintain the constant temperature for 60-120 minutes to fix the internal structure of the green brick and form a sintered shape.

[0037] S53: After the heat preservation is completed, turn off the heating device and allow it to cool naturally to 80-100℃ at a rate of 1-2℃ / min, then remove it to form sintered bricks.

[0038] Optionally, S6 specifically includes:

[0039] S61: Prepare a hydrophobic treatment solution, wherein the hydrophobic treatment solution is prepared by mixing a silane hydrophobic agent with anhydrous ethanol at a volume ratio of 1:4 to 1:6;

[0040] S62: Clean and dry the surface of the sintered brick to a moisture content of less than 1%, and spray the hydrophobic treatment liquid evenly onto the surface of the brick using a spraying method, with the spraying amount controlled at 80-120mL / m².

[0041] S63: After spraying, let it stand at room temperature for 30-60 minutes to pre-dry;

[0042] S64: Place the brick in a drying oven and heat it at a constant temperature of 80-100℃ for 1-2 hours to complete the cross-linking and curing process of the hydrophobic agent. After taking it out, it becomes the final thermal insulation brick product.

[0043] The beneficial effects of this invention are:

[0044] This invention, by introducing industrial waste, clay, foaming agent and reinforcing fiber in a synergistic ratio at the raw material stage, combined with wet ball milling and homogenization stirring, forms a slurry system with uniform particle distribution and stable structure, effectively controlling the uniformity of raw materials and bonding compatibility before the molding of thermal insulation bricks.

[0045] This invention introduces a surface hydrophobic treatment process through low-temperature thermosetting, which constructs a stable hydrophobic layer. This not only prevents water vapor intrusion that could increase thermal conductivity, but also enhances the moisture resistance and stability of the exterior wall during use. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 is a schematic diagram of the preparation method of green low thermal conductivity insulating brick according to an embodiment of the present invention. Detailed Implementation

[0048] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0049] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0050] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0051] Example 1

[0052] As shown in Figure 1, a method for preparing green low thermal conductivity insulating bricks suitable for exterior walls includes the following steps:

[0053] S1: Weigh out industrial waste, clay, foaming agent and reinforcing fiber in proportion, and mix them in a preliminary manner to obtain a preliminary mixture;

[0054] S2: The preliminary mixture is subjected to wet ball milling to obtain a ball mill slurry;

[0055] S3: Add binder and water to the ball mill slurry and stir to homogenize it to obtain a homogenized slurry;

[0056] S4: The homogenized slurry is injected into the mold and formed by pressing to obtain the green brick body;

[0057] S5: Low-temperature sintering treatment is performed on the green brick body to obtain sintered brick body;

[0058] S6: Perform surface hydrophobic treatment on sintered bricks to obtain finished thermal insulation bricks.

[0059] The industrial waste is selected from fly ash; the foaming agent is sodium bicarbonate; and the reinforcing fiber is selected from glass fiber.

[0060] The mass percentages of industrial waste, clay, foaming agent, and reinforcing fiber are as follows: industrial waste 62%; clay 25%; foaming agent 10%; reinforcing fiber 3%.

[0061] S1 specifically includes:

[0062] S11: Weigh industrial waste, clay, foaming agent and reinforcing fiber according to the set mass percentage, and control the feeding error of each raw material within ±1% of the target mass;

[0063] S12: First, put industrial waste and clay into a dry mixing device and premix them at a speed of 150 rpm for 4 minutes to form a bottom mixture with uniformly distributed powder.

[0064] S13: Add the foaming agent and reinforcing fiber to the bottom mixture in sequence, continue the dry mixing operation, keep the speed constant, and mix for 6 minutes until all raw materials are fully dispersed;

[0065] S14: The mixture obtained in S13 is sieved with a sieve aperture of 1.8 mm to remove agglomerates and large particulate impurities, resulting in a preliminary mixture with uniform particle size distribution.

[0066] S2 specifically includes:

[0067] S21: Put the preliminary mixture into a ball mill jar and add deionized water to control the solid-liquid mass ratio at 1:1.4;

[0068] S22: Add zirconium oxide ball milling media to the ball mill jar, and control the ball-to-material ratio to be 1:2.5;

[0069] S23: Set the ball mill speed to 250 rpm and the continuous wet ball milling time to 2 hours;

[0070] S24: After ball milling, the slurry is filtered through a 200-mesh sieve to remove coarse particles that have not been fully ground, resulting in a ball-milled slurry with a uniform particle size distribution.

[0071] S3 specifically includes:

[0072] S31: Place the ball-milled slurry in a high-speed mixing vessel and add a water-soluble binder at 4% of the slurry mass. The binder is polyvinyl alcohol with a molecular weight of 30,000.

[0073] S32: Add deionized water to control the solid content of the slurry at 50%;

[0074] S33: Turn on the stirring device, set the stirring speed to 500 rpm, and the stirring time to 25 minutes to allow the binder to fully dissolve and be evenly distributed in the system;

[0075] S34: After mixing, filter through a 120-mesh sieve to remove any possible lumps or impurities, resulting in a homogenized slurry with fluidity and uniformity within the set range. By precisely controlling the amount of binder, the water ratio, and the mixing parameters, the slurry maintains its castability while possessing good bonding properties, providing a homogenized base slurry with stable particle size, sufficient bonding, and moderate rheological properties for subsequent pressing and molding processes.

[0076] The adhesive is polyvinyl alcohol.

[0077] S4 specifically includes:

[0078] S41: Slowly inject the homogenized slurry into a metal mold with a breathable drainage hole, control the injection rate at 15mL / s, and the injection volume corresponds to 97% of the mold cavity volume; and let it stand for 2 minutes to allow the slurry to spread fully in the mold cavity and remove air bubbles.

[0079] S42: After grouting is completed, the mold is sent into the hydraulic pressing equipment, and the pressing pressure is set to 15MPa and the holding time is 60 seconds.

[0080] S43: After pressing is completed, the green body formed in the mold is demolded and transferred to a drying tray to obtain a green brick body with initial structural strength and dimensional stability. The above steps achieve the densification and preliminary shaping of the slurry by controlling the grouting speed, pressing pressure and holding time, ensuring that the green brick body meets the process requirements of subsequent sintering in terms of dimensional control, pore distribution and structural integrity, and forming a stable molding foundation.

[0081] S5 specifically includes:

[0082] S51: Place the green bricks obtained in S4 into an electric heating sintering furnace, set the heating rate to 3℃ / min, raise the temperature from room temperature to 330℃, and keep it constant for 30 minutes to remove residual moisture and volatile components inside the bricks.

[0083] S52: Continue to raise the temperature at a rate of 4℃ / min to the low-temperature sintering temperature of 700℃, and maintain the constant temperature for 90 minutes to fix the internal structure of the green brick and form a stable sintering morphology.

[0084] S53: After the heat preservation is completed, turn off the heating device and allow it to cool naturally to 90°C at a rate of 1.5°C / min. Then remove the brick to form a sintered brick.

[0085] S6 specifically includes:

[0086] S61: Prepare a hydrophobic treatment solution, which is prepared by mixing a silane hydrophobic agent with anhydrous ethanol at a volume ratio of 1:5;

[0087] S62: Clean and dry the surface of the sintered bricks until the moisture content is less than 1%, and spray the hydrophobic treatment liquid evenly onto the surface of the bricks using a spraying method, with the spraying amount controlled at 100mL / m².

[0088] S63: After spraying, let it stand at room temperature for 40 minutes to pre-dry;

[0089] S64: Place the brick in a drying oven and heat it at a constant temperature of 90℃ for 1.5 hours to complete the cross-linking and curing process of the hydrophobic agent. After taking it out, it becomes the final thermal insulation brick product.

[0090] Example 2

[0091] S1: Weigh the raw materials according to the mass percentage, namely 74% slag, 20% clay, 5% hydrogen peroxide and 1% ceramic fiber, and control the feeding error to not exceed ±1%; put the fly ash and clay into the dry mixing device and mix for 3 minutes at 100 rpm to form a uniform bottom mixture. Then add sodium bicarbonate and glass fiber, maintain the speed and dry mix for 5 minutes. Then sieve through a 1.5 mm sieve to remove large particles and agglomerates to obtain a preliminary mixture.

[0092] S2: The above preliminary mixture is put into a ball mill jar, and deionized water is added to control the solid-liquid mass ratio at 1:1.2. At the same time, zirconia ball milling media are added to control the ball-to-material ratio at 1:2. The ball mill is set to a speed of 200 rpm and wet ball milling is carried out for 1.5 hours. After ball milling, the mixture is filtered through a 200-mesh sieve to remove coarse particles that are not fully ground, and a homogeneous ball mill slurry is obtained.

[0093] S3: Transfer the ball-milled slurry into a high-speed mixing vessel, add 3% starch binder (molecular weight approximately 20,000) by the slurry mass, and add deionized water to control the solid content of the slurry at 45%; stir at a set speed of 400 rpm for 15 minutes to ensure uniform dispersion of the system, and then further filter through a 120-mesh sieve to remove glue lumps and impurities to obtain a stable and homogenized slurry;

[0094] S4: Inject the homogenized slurry into a metal mold with vents at a grouting rate of 10 mL / s, with the grouting volume accounting for 95% of the mold cavity volume. Let it stand for 1 minute to release the air. Set the pressure to 10 MPa in the hydraulic pressing equipment, hold the pressure for 30 seconds, and then complete the pressing and demolding to obtain a dense green brick.

[0095] S5: Place the obtained green bricks into an electric heating sintering furnace and heat them from room temperature to 300°C at a heating rate of 2°C / min, and maintain the temperature for 20 minutes to remove moisture and volatile components; then heat them to 650°C at a rate of 3°C / min and maintain the temperature for 60 minutes to complete low-temperature sintering; after the holding period, turn off the electric heating device and cool them to 80°C at a rate of 1°C / min before removing them to obtain sintered bricks;

[0096] S6: Prepare a hydrophobic treatment solution by mixing silane hydrophobic agent with anhydrous ethanol at a volume ratio of 1:4; thoroughly clean and dry the surface of the sintered brick until the moisture content is less than 1%; uniformly spray the hydrophobic solution using a spraying method, with the spraying amount controlled at 80mL / m²; after spraying, let it stand at room temperature for 30 minutes, and then place it in a drying oven and heat it at a constant temperature of 80℃ for 1 hour to complete the cross-linking and curing treatment of the hydrophobic agent, and finally obtain the finished green low thermal conductivity insulation brick.

[0097] Example 3

[0098] S1: Weigh the raw materials according to the mass percentage, in the following order: 50% construction waste powder, 30% clay, 15% aluminum powder and 5% glass fiber, and control the feeding error to not exceed ±1%; put the fly ash and clay into the dry mixing device and mix for 5 minutes at a speed of 200 rpm to form a uniform bottom mixture. Then, continue to add sodium bicarbonate and glass fiber, maintain the speed, and dry mix for 8 minutes. Then, sieve through a 2.0 mm sieve to remove large particles and agglomerates to obtain a preliminary mixture.

[0099] S2: The above preliminary mixture is put into a ball mill jar, and deionized water is added to control the solid-liquid mass ratio at 1:1.6. At the same time, zirconia ball milling media are added to control the ball-to-material ratio at 1:3. The ball mill is set to a speed of 300 rpm and wet ball milling is carried out for 2.5 hours. After ball milling, the mixture is filtered through a 200-mesh sieve to remove coarse particles that are not fully ground, and a homogeneous ball mill slurry is obtained.

[0100] S3: Transfer the ball-milled slurry into a high-speed mixing tank, add silicate cement binder (molecular weight approximately 50,000) at 6% of the slurry mass, and add deionized water to control the solid content of the slurry at 55%; stir at a set speed of 600 rpm for 30 minutes to ensure uniform dispersion of the system, and then further filter through a 120-mesh sieve to remove lumps and impurities to obtain a stable and homogenized slurry;

[0101] S4: Inject the homogenized slurry into a metal mold with vents at a slurry injection rate of 20 mL / s, with the slurry volume accounting for 98% of the mold cavity volume. Let it stand for 3 minutes to release the air. Set the pressure to 20 MPa in the hydraulic pressing equipment, hold the pressure for 90 seconds, and then complete the pressing and demolding to obtain a dense green brick.

[0102] S5: The obtained green brick body is placed in an electric heating sintering furnace and heated from room temperature to 350°C at a heating rate of 4°C / min, and kept at a constant temperature for 40 minutes to remove moisture and volatile components; then the temperature is increased to 750°C at 5°C / min and kept at a constant temperature for 120 minutes to complete low-temperature sintering; after the holding time is completed, the electric heating device is turned off, and the brick body is cooled to 100°C at a rate of 2°C / min and then removed to obtain the sintered brick body;

[0103] S6: Prepare a hydrophobic treatment solution by mixing silane hydrophobic agent with anhydrous ethanol at a volume ratio of 1:6; thoroughly clean and dry the surface of the sintered brick to a moisture content of less than 1%; uniformly spray the hydrophobic solution using a spraying method, with the spraying amount controlled at 120mL / m²; after spraying, let it stand at room temperature for 60 minutes, then place it in a drying oven and heat it at a constant temperature of 100℃ for 2 hours to complete the cross-linking and curing treatment of the hydrophobic agent, and finally obtain the finished green low thermal conductivity insulation brick.

[0104] Comparative Example 1

[0105] Raw material mixing: Weigh out 65% expanded perlite, 30% kaolin, and 5% sodium carboxymethyl cellulose as binders; mix all components in a low-speed mixer at 100 rpm for 5 minutes to obtain a dry mix;

[0106] Compression molding: Add water to the dry mix at a mass ratio of 1:0.25, stir evenly to form a compressible wet material; press the wet material directly into a rectangular mold, press with 10MPa pressure for 30 seconds, and demold to obtain the green brick body;

[0107] High-temperature sintering: The green bricks are placed in a tunnel kiln and heated to 1000℃ at a heating rate of 5℃ / min. They are then sintered at this temperature for 90 minutes and then naturally cooled to room temperature to obtain the finished insulation bricks.

[0108] Table 1 Comparison of Performance Parameters of Finished Thermal Insulation Bricks

[0109] Comparative Example 1 | Example 2 | Example 3 | Comparative Example 1 | Thermal Conductivity (W / m·K) | 0.068 | 0.076 | 0.072 | 0.12 | Apparent Density (kg / m³) | 860 | 900 | 880 | 1150 | Compressive Strength (MPa) | 12.5 | 10.3 | 11.1 | 7.2 | Water Absorption (%) | 7.1 | 9.4 | 8.7 | 16.8 | Heat Averaging Deviation (°C) | 1.6 | 2.3 | 24.8 | Freeze-Thaw Cycles (times) | ≥60 | ≥45 | ≥50 | ≥20 | Hydrophobic Contact Angle (°) | 12 | 3.5 | 117.2 | 119.6 | 78.4 | Sintering Energy Consumption (kWh / m²) | 6.2 | 5.8 | 6.5 | 9.5 surface

[0110] As can be seen from Table 1 above, the synergistic optimization of the formula and the control of uniform cell size in Example 1 resulted in a thermal conductivity of 0.068 W / m·K, significantly better than that of the traditional formula in Comparative Example 1 (0.120 W / m·K), with a thermal insulation capacity improvement of over 43%. The use of PVA reinforcement and precise control of pressing parameters in Example 1 increased the compressive strength to 12.5 MPa, approximately 73% higher than Comparative Example 1, resulting in a denser and more stable brick structure. The water absorption rate of Example 1 was only 7.1%, while that of Comparative Example 1 was as high as 16.8%, significantly improving moisture resistance. The bricks produced in Example 1 had a uniform internal structure, good heat conduction balance, and the lowest heat uniformity deviation. Furthermore, they withstood ≥60 freeze-thaw cycles, exhibiting stronger stability in cold or humid regions. Optimized with a silane hydrophobic agent, the surface contact angle of Example 1 reached 123.5°, demonstrating strong water repellency, while the comparative example only had 78.4°, indicating significant surface water adsorption. Although Example 1 employed a two-stage low-temperature sintering strategy, the total energy consumption was controlled at 6.2 kWh. The energy consumption per kWh / m² is significantly lower than that of the comparative high-temperature sintering, demonstrating energy-saving advantages. In summary, Example 1 is superior to Examples 2 and 3 and the traditional comparative scheme in multiple key indicators such as thermal conductivity, mechanical properties, water resistance, and thermal stability. Moreover, it balances energy saving and performance in terms of energy consumption control, making it the optimal implementation method in the technical solution of this invention.

[0111] Table 2 Comparison of other performance parameters

[0112] Comparative Example 1 | Example 2 | Example 3 | Comparative Example 1 | Porosity (%) | 42.3 | 39.5 | 40.1 | 28.4 | Average Pore Diameter (μm) | 85 | 110 | 95 | 180 | Impact Strength (N·m) | 18.6 | 15.4 | 16.7 | 9.8 | Wet Bond Strength (with Cement Mortar / N·mm²) | 0.9 | 60.8 | 10.8 | 50.5 | 6 | Surface Hardness (Shore Type D) | 65 | 61 | 63 | 52 | Strength Retention Rate after UV Aging (%) | 92.8 | 87.3 | 89.5 | 74.2 surface

[0113] As can be seen from Table 2 above, Example 1 is the best in terms of controlling the cell structure, with a porosity of 42.3% and an average pore diameter of 85 μm, balancing low thermal conductivity and mechanical strength. Comparative Example 1 has large and uneven cells, resulting in compromised thermal conductivity and strength. Due to the uniform dispersion of raw material particles and the support structure of reinforcing fibers, Example 1 has an impact strength of 18.6 N·m, which is nearly 90% higher than that of the comparative example, and performs better in handling, transportation, and construction. The bonding strength with cement mortar in the wet state reaches 0.96 N / mm², ensuring that it is not easy to fall off after construction, which is better than other examples and traditional products, improving the overall building stability. The surface hardness of Example 1 reaches Shore 65D, which is higher than that of Examples 2 / 3 and traditional bricks, making it suitable for long-term exposure of exterior walls, with better resistance to wind and sand and abrasion. In the UV accelerated aging test, the strength retention rate of Example 1 is as high as 92.8%, which is significantly better than that of Comparative Example 1 (74.2%), indicating that the material structure is stable and has excellent aging resistance.

[0114] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0115] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing green, low thermal conductivity insulating bricks suitable for exterior walls, characterized in that, Includes the following steps: S1: Weigh out industrial waste, clay, foaming agent, and reinforcing fiber according to the proportions, and mix them initially to obtain a preliminary mixture; S2: Perform wet ball milling on the preliminary mixture to obtain a ball mill slurry; S3: Add binder and water to the ball mill slurry, and stir and homogenize it to obtain a homogenized slurry; S4: Inject the homogenized slurry into a mold, and shape it through a pressing process to obtain a green brick body; S5: Low-temperature sintering treatment is performed on the green brick body to obtain sintered brick body; S6: Perform surface hydrophobic treatment on sintered bricks to obtain finished thermal insulation bricks.

2. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, The industrial waste is selected from fly ash, slag or construction waste powder; the foaming agent is sodium bicarbonate, hydrogen peroxide or aluminum powder; the reinforcing fiber is selected from glass fiber or ceramic fiber.

3. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, The mass percentages of the industrial waste, clay, foaming agent, and reinforcing fiber are as follows: industrial waste 50-74%; clay 20-30%; foaming agent 5-15%; reinforcing fiber 1-5%.

4. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S1 specifically includes: S11: Weighing industrial waste, clay, foaming agent, and reinforcing fiber according to the set mass percentage, with the feeding error of each raw material controlled within ±1% of the target mass; S12: First, putting the industrial waste and clay into a dry mixing device and pre-mixing at a speed of 100-200 rpm for 3-5 minutes to form a bottom mixture with uniformly distributed powder; S13: Adding the foaming agent and reinforcing fiber to the bottom mixture in sequence, continuing the dry mixing operation, maintaining the speed unchanged, and mixing for 5-8 minutes; S14: Sieving the mixture obtained in S13 through a sieve with a sieve aperture size of 1.5-2.0 mm to remove agglomerates and large particulate impurities, obtaining a preliminary mixture.

5. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S2 specifically includes: S21: adding the preliminary mixture into the ball mill jar and adding deionized water to control the solid-liquid mass ratio at 1:1.2 to 1:1.6; S22: adding zirconia ball milling media into the ball mill jar and controlling the ball-to-material ratio at 1:2 to 1:3; S23: setting the ball mill speed to 200-300 rpm and the continuous wet ball milling time to 1.5-2.5 hours; S24: after ball milling, filtering the slurry through a 200-mesh sieve to remove insufficiently ground coarse particles and obtain the ball milled slurry.

6. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S3 specifically includes: S31: placing the ball-milled slurry in a high-speed mixing vessel and adding a water-soluble binder at 3-6% of the slurry mass, wherein the binder is polyvinyl alcohol with a molecular weight of 20,000 to 50,000; S32: adding deionized water to control the solid content of the slurry at 45-55%; S33: turning on the stirring device, setting the stirring speed to 400-600 rpm, and the stirring time to 15-30 minutes; S34: after stirring, filtering through a 120-mesh sieve to remove any possible lumps or impurities to obtain a homogenized slurry.

7. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 6, characterized in that, The adhesive is polyvinyl alcohol, starch glue, or silicate cement.

8. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S4 specifically includes: S41: Slowly injecting the homogenized slurry into a metal mold with a breathable drainage hole, controlling the injection rate to be 10-20 mL / s, and the injection volume corresponding to 95%-98% of the mold cavity volume; and letting it stand for 1-3 minutes; S42: After the injection is completed, sending the mold into a hydraulic pressing device, setting the pressing pressure to 10-20 MPa, and the holding time to 30-90 seconds; S43: After pressing is completed, demolding the formed green brick in the mold and transferring it to a drying tray to obtain the green brick body.

9. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S5 specifically includes: S51: placing the green brick obtained in S4 into an electrically heated sintering furnace, setting the heating rate to 2-4℃ / min, raising the temperature from room temperature to 300-350℃, and maintaining the constant temperature for 20-40 minutes to remove residual moisture and volatile components inside the brick; S52: continuing to raise the temperature at a rate of 3-5℃ / min to a low-temperature sintering temperature of 650-750℃, maintaining the constant temperature for 60-120 minutes to fix the internal structure of the green brick and form a sintered shape; S53: after completing the heat preservation, turning off the heating device, and allowing it to cool naturally to 80-100℃ at a rate of 1-2℃ / min, and then removing it to form a sintered brick.

10. The method for preparing a green low thermal conductivity insulating brick suitable for exterior walls according to claim 1, characterized in that, S6 specifically includes: S61: preparing a hydrophobic treatment solution, which is prepared by mixing a silane hydrophobic agent with anhydrous ethanol at a volume ratio of 1:4 to 1:6; S62: cleaning and drying the surface of the sintered brick to a moisture content of less than 1%, and uniformly spraying the hydrophobic treatment solution onto the surface of the brick using a spraying method, with the spraying amount controlled at 80-120 mL / m²; S63: after spraying, allowing it to stand at room temperature for 30-60 minutes to pre-dry; S64: placing the brick in a drying oven and heating it at a constant temperature of 80-100℃ for 1-2 hours to complete the cross-linking and curing process of the hydrophobic agent, and then removing it to obtain the final thermal insulation brick product.

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