Hard inorganic porous material for pipeline heat preservation and preparation method thereof
By optimizing the proportions and processes of aluminate cement, lightweight aggregate, and reinforcing fibers, a rigid inorganic porous material was prepared that maintains its strength at high temperatures. This solves the problem of unstable performance of existing materials at high temperatures, enabling the preparation of low-energy-consumption and large-size irregularly shaped products, which are suitable for high-temperature thermal pipelines.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-03
AI Technical Summary
Existing rigid pipe insulation materials have unstable performance in high-temperature environments, high energy consumption, and are difficult to manufacture large-size and irregularly shaped products.
Rigid inorganic porous materials are prepared by using raw materials such as aluminate cement, lightweight aggregate and reinforcing fiber through dry mixing, wet mixing and foaming molding processes. High temperature and high pressure curing is avoided, and the raw material ratio and process steps are optimized to improve the temperature resistance and formability of the materials.
The prepared material maintains good strength at high temperatures, has low energy consumption, and is suitable for insulation of large and irregularly shaped pipes. It has high density, high hardness and excellent insulation performance, and is suitable for harsh scenarios such as high-temperature thermal pipelines.
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Figure CN121779077A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of rigid thermal insulation materials, specifically a rigid inorganic porous material for pipe insulation and its preparation method. Background Technology
[0002] Pipe insulation materials are widely used in heat transmission, industrial pipelines, and other fields. Their performance directly affects the insulation effect, safety, and service life. Currently, the mainstream rigid pipe insulation materials on the market mainly include microporous calcium silicate pipe shells, expanded perlite pipe shells, and rigid polyurethane pipe shells. Microporous calcium silicate pipe shells utilize a hydrothermal synthesis process, requiring the calcium silicate raw materials and reinforcing fibers to be mixed into a slurry, pressed, and then cured in an autoclave. This process has three major problems: First, autoclaving is time-consuming and energy-intensive, leading to higher product costs; second, the pipe shell strength is extremely low before autoclaving, allowing only small-sized products to be produced, which cannot meet the insulation requirements of large and irregularly shaped pipelines; third, a large amount of residual crystal water remains inside the material, and under long-term high-temperature operation, the evaporation of this crystal water causes a sharp decrease in material strength, affecting its stability in use.
[0003] Expanded perlite tube shells are manufactured using a die-casting process, in which expanded perlite granules sprayed with adhesive are pressed into shape and then fixed at high temperature to remove the solvent. The drawbacks of this process are: the tube shells have low strength before solvent removal, limiting the production of large-size products; and the adhesive is prone to aging and failure at high temperatures, causing the product to crumble back into powder, resulting in a short service life.
[0004] The rigid polyurethane pipe shell is made by mixing black and white materials in a foaming process. Because polyurethane is an organic material, it has poor heat resistance and will carbonize in environments above 120°C. It can only be used at temperatures below 100°C and is not suitable for high-temperature pipeline insulation scenarios.
[0005] Therefore, there is an urgent need to develop a pipe insulation material with good temperature resistance, low energy consumption, the ability to manufacture large-size and irregularly shaped products, and stable performance, as well as its preparation method. Summary of the Invention
[0006] In response to the above situation, this invention proposes a rigid inorganic porous material for pipe insulation and its preparation method. By optimizing the raw material ratio and preparation steps, the prepared material has high density and high hardness, and maintains its strength performance in high-temperature environments.
[0007] To solve the above problems, the technical solution provided by the present invention is as follows: A method for preparing a rigid inorganic porous material for pipe insulation, characterized by comprising the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mix; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:(0.1~0.3):(0.1~0.3):(0.005~0.015); (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, then mix with dry mixture, add reinforcing fiber, continue mixing, add hydrogen peroxide, stir to obtain wet mixture; (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0008] Furthermore, in step (1), the admixture is one or more of fly ash, silica fume and slag; the lightweight aggregate is one or more of vitrified microspheres, aerogel powder and expanded perlite; wherein the particle size of the vitrified microspheres is 50-120 mesh, the particle size of the aerogel powder is 300-500 mesh, and the particle size of the expanded perlite is 50-120 mesh.
[0009] Furthermore, in step (2), the mass of water added is 35-70% of the dry mixture, the mass of foam stabilizer added is 0.05-0.25% of the dry mixture, and the mass of water glass added is 0.1-2% of the water; the foam stabilizer is one or more of HPMC (hydroxypropyl methylcellulose), polyvinyl alcohol, and 901 adhesive powder; Furthermore, in step (2), the reinforcing fiber is one or both of glass fiber and basalt fiber, the amount of reinforcing fiber added is 0.5-1.5% of the total mass of aluminate cement and admixture, and the length of the reinforcing fiber is 9-12 mm; the concentration of hydrogen peroxide is 30-50%, and the added mass of hydrogen peroxide is 5-8% of the total mass of aluminate cement and admixture.
[0010] Furthermore, in step (3), the semi-finished product is left to stand naturally for ≥24 hours, the humidity of the demolding and curing environment is ≥80%RH, the temperature is 15~30℃, and the curing time is ≥3 days.
[0011] Furthermore, the drying temperature in step (4) is 100-200℃.
[0012] Beneficial effects: (1) Excellent temperature resistance: Aluminate cement is used as the matrix material, and the temperature resistance can reach 1000℃, which is much higher than that of rigid polyurethane pipe shell (≤100℃). There is no problem of evaporation of crystal water or carbonization of organic matter at high temperature. After treatment at 450℃ for 8 hours, the compressive strength retention rate is ≥75%, which is suitable for harsh scenarios such as high temperature thermal pipelines.
[0013] (2) Low energy consumption in preparation: No need for high temperature and high pressure curing equipment such as autoclave, only room temperature and pressure curing is required. Compared with the hydrothermal synthesis process of microporous calcium silicate tube shell, it greatly reduces energy consumption and production cost.
[0014] (3) Good formability: The slurry casting foaming molding process is adopted. The slurry has excellent fluidity and can fill molds of different sizes and shapes. This solves the limitation that existing microporous calcium silicate pipe shells and expanded perlite pipe shells can only produce small-sized products. Large and irregular pipe shells can be mass-produced to meet diverse pipeline insulation needs.
[0015] (4) Stable overall performance: The density of the finished material is 200-300 kg / m³, the compressive strength is 0.15-0.80 MPa, and the thermal conductivity at room temperature is 0.055-0.070 W / (m·K). It has the advantages of being lightweight, high-strength and excellent thermal insulation performance. Moreover, the raw materials are widely available, the preparation process is simple, and it is easy to promote industrialization. Attached Figure Description
[0016] Figure 1 This is a microscopic image of the hard inorganic porous material prepared in Example 1 of the present invention; Figure 2 This is a microscopic image of the hard inorganic porous material prepared in Example 1 of the present invention; Figure 3 This is a flowchart illustrating a method for preparing a rigid inorganic porous material for pipe insulation according to the present invention. Detailed Implementation
[0017] The present invention will be further described in detail below with reference to specific preferred embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] Example 1 The basics are as follows: Figure 3 As shown, this embodiment provides a method for preparing a rigid inorganic porous material for pipe insulation, including the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.1:0.3:0.012; Specifically, add 1000g of aluminate cement, 100g of fly ash, 300g of aerogel powder and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0019] (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.2g of HPMC and 4.2g of water glass to 700g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of glass fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber, and raw material dry mixture are evenly mixed. Finally, add 70g of hydrogen peroxide and stir for 10 seconds to obtain a wet mixture.
[0020] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0021] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0022] Specifically, the cured hard inorganic porous material semi-finished product is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material. The prepared hard inorganic porous material finished product is shown in the attached figure. Figure 1 and 2 As shown.
[0023] Example 2 This embodiment provides a method for preparing a rigid inorganic porous material for pipe insulation, including the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.1:0.3:0.012; Specifically, add 1000g of aluminate cement, 100g of slag powder, 100g of expanded perlite and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0024] (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.2g of polyvinyl alcohol and 4.2g of water glass to 650g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of glass fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber and raw material dry mixture are evenly mixed. Finally, add 75g of hydrogen peroxide and stir for 15 seconds to obtain a wet mixture.
[0025] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0026] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0027] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0028] Example 3 This embodiment provides a method for preparing a rigid inorganic porous material for pipe insulation, including the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.1:0.1:0.012; Specifically, add 1000g of aluminate cement, 100g of fly ash, 100g of vitrified microspheres and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0029] (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.2g of HPMC and 4.2g of water glass to 550g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of basalt fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber and raw material dry mixture are evenly mixed. Finally, add 60g of hydrogen peroxide and stir for 20 seconds to obtain a wet mixture.
[0030] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0031] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0032] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0033] Example 4 This embodiment provides a method for preparing a rigid inorganic porous material for pipe insulation, including the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mix; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.2:0.15:0.01; Specifically, add 1000g of aluminate cement, 200g of fly ash, 150g of vitrified microspheres and 10g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0034] (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.4g of HPMC and 4.5g of water glass to 550g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of basalt fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber and raw material dry mixture are evenly mixed. Finally, add 60g of hydrogen peroxide and stir for 20 seconds to obtain a wet mixture.
[0035] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0036] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0037] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0038] Example 5 This embodiment provides a method for preparing a rigid inorganic porous material for pipe insulation, including the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.2:0.3:0.012; Specifically, add 1000g of aluminate cement, 200g of fly ash, 300g of vitrified microspheres and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0039] (2) Raw material wet mixing: Add foam stabilizer and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.4g of HPMC and 4.5g of water glass to 700g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of basalt fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber and raw material dry mixture are evenly mixed. Finally, add 60g of hydrogen peroxide and stir for 20 seconds to obtain a wet mixture.
[0040] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0041] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0042] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0043] Comparative Example 1 This comparative example provides a method for preparing a rigid inorganic porous material for pipe insulation without adding lightweight aggregate, comprising the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture and calcium stearate is 1:0.2:0.012; Specifically, add 1000g of aluminate cement, 200g of fly ash and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute to obtain a dry mix.
[0044] (2) Raw material wet mixing: Add HPMC and water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 1.4g of HPMC and 4.5g of water glass to 600g of water, stir to dissolve, and then add to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of basalt fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber and raw material dry mixture are evenly mixed. Finally, add 60g of hydrogen peroxide and stir for 20 seconds to obtain a wet mixture.
[0045] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0046] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0047] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0048] Comparative Example 2 This comparative example provides a method for preparing a rigid inorganic porous material for pipe insulation without adding a foam stabilizer, comprising the following steps: (1) Dry mixing of raw materials: Add the preset amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; the mass ratio of aluminate cement, admixture, lightweight aggregate and calcium stearate is 1:0.1:0.1:0.012; Specifically, add 1000g of aluminate cement, 100g of fly ash, 100g of vitrified microspheres and 12g of calcium stearate to the mixing tank, mix and stir for more than 1 minute, and stir the raw materials until they are evenly mixed to obtain a dry mix.
[0049] (2) Raw material wet mixing: Add water glass to water, stir to dissolve, and then mix with dry mixture. Then add reinforcing fiber, continue mixing, add hydrogen peroxide, and stir to obtain wet mixture; Specifically, add 4.5g of water glass to 600g of water, stir to dissolve, and then add it to a mixing tank. Next, add the dry mixture to the mixing tank and start stirring for more than 1 minute. Then, add 10g of basalt fiber in three or more equal batches to the mixing tank and mix for more than 1 minute to ensure that the water, fiber, and raw material dry mixture are evenly mixed. Finally, add 60g of hydrogen peroxide and stir for 20 seconds to obtain a wet mixture.
[0050] (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. Specifically, the obtained wet mixture is transferred to a molding die within 2 minutes of stopping the mixing. The wet mixture foams and molds in the molding die to obtain a rigid inorganic porous material semi-finished product. The rigid inorganic porous material semi-finished product and the molding die are placed naturally under a ventilated shelter for more than 24 hours, and then demolded and cured in an environment with a humidity of not less than 80% RH and a temperature of 15-30℃ for at least 3 days.
[0051] (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
[0052] Specifically, the semi-finished hard inorganic porous material after curing is dried to constant weight at 100℃~200℃ and then cooled to room temperature to obtain the finished hard inorganic porous material.
[0053] The materials prepared in the above embodiments and comparative examples were subjected to performance tests, and the test results are shown in Table 1 below: Table 1. Performance test results of hard inorganic porous materials in the examples and comparative examples. The results in Table 1 show that the hard inorganic porous material prepared in the embodiments of the present invention has a moderate density. The prepared hard inorganic porous material can have both suitable compressive strength and good thermal conductivity, and the compressive strength can still be retained by more than 75% after being treated at 450℃ for 8 hours.
[0054] Compared to the example, Comparative Example 1 did not add lightweight aggregate. Lightweight aggregate is a material with a porous structure. Adding an appropriate amount of lightweight aggregate can fill the gaps in the cement paste, and the cement hydration products can penetrate into the pores of the lightweight aggregate to form mechanical interlocking, avoiding the formation of large pores in the cement skeleton, thereby improving the overall strength of the material. Excessive lightweight aggregate will lead to an increase in defects in the transition zone between the lightweight aggregate and the paste, reducing the strength.
[0055] Lightweight aggregates have high porosity and low thermal conductivity. Furthermore, cement hydration products can seal the openings of lightweight aggregates to form a closed-cell structure, which can significantly reduce the overall thermal conductivity of the material.
[0056] Comparative Example 2, unlike the Example, did not contain a foam stabilizer. A foam stabilizer reduces the gas-liquid interfacial tension, resulting in smaller, more uniformly distributed bubbles and preventing the formation of large-diameter interconnected pores. The formation of more fine, uniform pores reduces stress concentration points in the material, improves structural uniformity, and thus enhances compressive strength. Increased closed-cell structures and smaller pore sizes in the material also reduce thermal conductivity.
Claims
1. A method for preparing a rigid inorganic porous material for pipe insulation, characterized in that, Includes the following steps: (1) Dry mixing of raw materials: Add the pre-set amount of aluminate cement, admixture, lightweight aggregate and calcium stearate to the mixing tank, mix and stir until uniform to obtain dry mixture; The mass ratio of the aluminate cement, admixture, lightweight aggregate, and calcium stearate is 1:(0.1-0.3):(0.1-0.3):(0.005-0.015). (2) Raw material wet mixing: Add foam stabilizer and water glass to water and stir to dissolve. Then stir and mix with dry mixture. Then add reinforcing fiber, continue mixing and add hydrogen peroxide. Stir to obtain wet mixture. (3) Molding preparation: The wet mixture is transferred to the molding mold for foaming and molding to obtain a hard inorganic porous material semi-finished product. The semi-finished product is placed naturally, demolded and cured. (4) Drying the finished product: Dry the cured semi-finished product to constant weight and cool it to room temperature to obtain the hard inorganic porous material finished product.
2. The method for preparing a rigid inorganic porous material for pipe insulation according to claim 1, characterized in that, In step (1), the admixture is one or more of fly ash, silica fume and slag; the lightweight aggregate is one or more of vitrified microspheres, aerogel powder and expanded perlite; wherein the particle size of the vitrified microspheres is 50-120 mesh, the particle size of the aerogel powder is 300-500 mesh, and the particle size of the expanded perlite is 50-120 mesh.
3. The method for preparing a rigid inorganic porous material for pipe insulation according to claim 1, characterized in that, In step (2), the water added is 35-70% of the dry mixture mass, the foam stabilizer added is 0.05-0.25% of the dry mixture mass, and the water glass added is 0.1-2% of the water mass; the foam stabilizer is one or more of HPMC, polyvinyl alcohol, and 901 adhesive powder.
4. The method for preparing a rigid inorganic porous material for pipe insulation according to claim 3, characterized in that, In step (2), the reinforcing fiber is one or both of glass fiber and basalt fiber. The amount of reinforcing fiber added is 0.5-1.5% of the total mass of aluminate cement and admixture, and the length of the reinforcing fiber is 9-12 mm. The concentration of hydrogen peroxide is 30-50%, and the mass of hydrogen peroxide added is 5-8% of the total mass of aluminate cement and admixture.
5. The method for preparing a rigid inorganic porous material for pipe insulation according to claim 1, characterized in that, In step (3), the semi-finished product is left to stand naturally for ≥24 hours, the humidity of the demolding and curing environment is ≥80%RH, the temperature is 15~30℃, and the curing time is ≥3 days.
6. The method for preparing a rigid inorganic porous material for pipe insulation according to claim 1, characterized in that, The drying temperature in step (4) is 100-200℃.
7. A rigid inorganic porous material for pipe insulation prepared by the preparation method according to any one of claims 1-6.