Fly ash high-temperature thermal insulation material and preparation method thereof

Abstract

The application discloses a fly ash high-temperature heat insulation material and a preparation method thereof, relates to the technical field of heat insulation materials, and comprises the following raw materials: 40-50 parts of fly ash floating beads, 20-28 parts of vermiculite, 15-21 parts of slag wool, 17-25 parts of borax, 0.17-0.26 parts of aluminum oxide and 15-20 parts of water glass; the mass ratio of the borax and the aluminum oxide is 1:0.01-0.015; the borax and the aluminum oxide are uniformly mixed, then the vermiculite and the slag wool are added and uniformly mixed to obtain mixture A; the fly ash floating beads and the water glass are mixed to obtain mixture B; the mixture A and the mixture B are uniformly mixed and calcined to obtain a fly ash high-temperature heat insulation blank; the blank is subjected to acidification treatment and is modified by polyaniline; and then, a YSZ / La2O3 composite coating is coated on the surface of the blank, so that the fly ash high-temperature heat insulation material is obtained. The application has excellent high-temperature heat insulation effect and pressure resistance.

Description

Technical Field

[0001] This application relates to the field of thermal insulation materials technology, and in particular to a high-temperature thermal insulation material made from fly ash and its preparation method. Background Technology

[0002] Industrial solid waste mainly refers to solid waste generated or left over from industrial production processes, such as tailings from mining operations, smelting slag, coal gangue from the coal-fired power industry, and fly ash. Statistics show that with the development of industries such as chemicals, steel, coal power, and non-ferrous metals, annual industrial solid waste emissions exceed 4 billion tons. If industrial solid waste is not properly treated, its long-term accumulation not only occupies a large amount of land and increases economic costs, but also seriously harms the ecological environment. Fly ash is a solid waste emitted after coal combustion in thermal power plants. Fly ash cenospheres are hollow microspheres that float on water, obtained by removing iron-rich ash from fly ash through sorting and electrostatic separation. Utilizing the hollow, thin-walled structure of fly ash cenospheres, their aluminum-silicon raw materials are mixed and sintered at high temperatures to produce thermal insulation materials, which are widely used in construction, petrochemicals, metallurgy, and machinery.

[0003] However, due to the hollow, thin-walled structure of fly ash cenospheres, their strength is relatively low. In some applications that require high mechanical stress or pressure, such as the load-bearing parts of building structures, fly ash cenosphere insulation materials may not meet the requirements and are prone to damage, thus limiting their application range. Summary of the Invention

[0004] To address the problems in the prior art, this application provides a high-temperature thermal insulation material made from fly ash and its preparation method.

[0005] This application provides a high-temperature thermal insulation material made from fly ash, which adopts the following technical solution:

[0006] A high-temperature thermal insulation material made of fly ash, comprising, by weight, 40-50 parts fly ash cenospheres, 20-28 parts vermiculite, 15-21 parts slag wool, 17-25 parts borax, 0.17-0.26 parts alumina, and 15-20 parts water glass; wherein the mass ratio of borax to alumina is 1:0.01-0.015.

[0007] Preferably, the particle size of the fly ash cenospheres is 150-850 μm.

[0008] This application also provides a method for preparing high-temperature thermal insulation material from fly ash, using the following technical solution:

[0009] A method for preparing a high-temperature thermal insulation material from fly ash includes the following steps:

[0010] S1. Mix 17-25 parts of borax and 0.17-0.25 parts of alumina evenly by weight, then add 20-28 parts of vermiculite and 15-21 parts of slag wool, and mix evenly to obtain mixture A; mix 40-50 parts of fly ash cenospheres with 15-20 parts of water glass to obtain mixture B;

[0011] S2. Mix mixture A and mixture B, stir for 20-30 minutes, then pre-dry at 110-130℃ for 10-16 hours; then calcine at 800-1000℃ for 3-6 hours to obtain high-temperature insulating fly ash billet;

[0012] S3. After acidification treatment of the high-temperature insulation blank of fly ash, an acidified high-temperature insulation blank of fly ash is obtained; the acidified high-temperature insulation blank of fly ash is modified by polyaniline to obtain polyaniline modified high-temperature insulation blank of fly ash.

[0013] S4. A YSZ / La2O3 composite coating is applied to the surface of polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition, and then sintered at 800-1000℃ for 4-6 hours in an argon atmosphere to obtain fly ash high-temperature insulation material.

[0014] Preferably, the acidification treatment of the high-temperature insulating fly ash billet in step S3 includes the following steps:

[0015] The high-temperature insulating material of fly ash is mixed in dilute acid and then heated at 75-85℃ for 7-9 hours. The product is filtered and washed with water until neutral. After vacuum drying, the acid-treated high-temperature insulating material of fly ash is obtained.

[0016] Preferably, the dilute acid is a 1-3 mol / L aqueous solution of HCl.

[0017] Preferably, the solid-liquid ratio of the fly ash high-temperature insulating blank to the dilute acid is 1:10-12 g / mL.

[0018] Preferably, the polyaniline-modified fly ash high-temperature insulating blank in S3 includes the following steps:

[0019] Weigh hexadecyltrimethylammonium bromide and stir it evenly with distilled water to obtain a hexadecyltrimethylammonium bromide solution; add distilled water to acidified fly ash high-temperature insulation billet and stir evenly, then add hexadecyltrimethylammonium bromide solution and react at 75-85℃ for 1-2 hours; filter the reactants under reduced pressure, wash and dry them to obtain hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation billet;

[0020] Aniline, hexadecyltrimethylammonium bromide-modified high-temperature insulating material from fly ash, and dodecylbenzene sulfonic acid were added to distilled water and stirred at room temperature to form an emulsion. Ammonium persulfate was dissolved in water and added dropwise to the emulsion. The reaction was carried out continuously at 4-6℃ for 12-14 hours. After the reaction was completed, the material was filtered under reduced pressure, washed, and dried to obtain polyaniline-modified high-temperature insulating material from fly ash.

[0021] Preferably, the mass ratio of the acidified fly ash high-temperature insulation blank to polyaniline is 1:0.0075-0.01.

[0022] Preferably, the mass ratio of the hexadecyltrimethylammonium bromide modified fly ash high-temperature insulating blank, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate is 1:0.7-0.9:0.8-0.9:1.5-2.5.

[0023] Preferably, the coating of the YSZ / La2O3 composite coating onto the surface of the polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition as described in S4 includes the following steps:

[0024] Yttrium-stabilized zirconium oxide powder and lanthanum oxide powder were dispersed in anhydrous ethanol and homogenized using an ultrasonic bath for 15-20 min. A dispersant was added, and the mixture was ultrasonically treated for 2-3 h to obtain a YSZ / La2O3 suspension. A polyaniline-modified fly ash high-temperature insulating blank was used as the cathode, and a graphite plate was used as the anode. The suspension was deposited at a voltage of 40-60V for 8-12 min.

[0025] Preferably, the dispersant is iodine; the mass ratio of the yttrium oxide stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 18-20:1:1.5-1.7.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. This application uses a mixture of alumina and borax, which effectively improves the high-temperature stability of borax. By introducing boron through borax, the diffusion and rearrangement between mineral particles can be promoted during the sintering process, making the sintering process more uniform and efficient, which helps to form a dense material structure and improve the mechanical properties and stability of the material.

[0028] 2. This application first uses the cationic surfactant hexadecyltrimethylammonium bromide as a modifier, and then uses electrostatic adsorption to adsorb hexadecyltrimethylammonium bromide onto the surface of the fly ash high-temperature insulation material. Then, using the principle of similar compatibility, aniline is introduced into the surface of the fly ash beads, and the aniline is polymerized by emulsion polymerization, thereby coating the hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation blank to obtain a polyaniline modified fly ash high-temperature insulation blank. The polyaniline modified fly ash high-temperature insulation blank can significantly improve the thermal stability of the material, and at the same time, it can also effectively improve the electrical conductivity, which is beneficial to the subsequent electrophoretic deposition coating.

[0029] 3. This application uses electrophoretic deposition to coat the surface of fly ash high-temperature resistant insulation material with a YSZ coating doped with rare earth La2O3, which can effectively enhance the high-temperature stability of fly ash high-temperature resistant insulation material; at the same time, the YSZ coating doped with rare earth La2O3 has high mechanical strength and good wear resistance, which helps to reduce the wear of the material during use, enhance its mechanical properties, and extend its service life. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments.

[0031] The chemical reagents used in the embodiments and comparative examples provided in this invention are all commercially available products.

[0032] Example 1

[0033] S1. Mix 17g of borax and 0.17g of alumina evenly (the mass ratio of borax to alumina is 1:0.01), add 20g of vermiculite and 15g of slag wool, and mix evenly to obtain mixture A; mix 40g of fly ash cenospheres with a particle size of 150-850μm with 15g of water glass to obtain mixture B;

[0034] S2. Mix mixture A and mixture B, stir for 20 minutes to form a uniformly mixed mud; after accumulating for 12 hours, press it into a cylindrical sample with a diameter of φ50mm×50mm under a pressure of 5MPa, then pre-dry it at 110℃ for 10 hours; then calcine it at 800℃ for 6 hours to obtain a high-temperature insulating fly ash billet.

[0035] S3. After acidification treatment of the high-temperature insulation blank made of fly ash, the acidified high-temperature insulation blank made of fly ash is obtained. The specific operation is as follows:

[0036] 20g of fly ash high-temperature insulation billet was mixed in 200mL of 1mol / L HCl aqueous solution, and then heated at 75℃ for 7h. The product was filtered and washed with water until neutral. After vacuum drying at 60℃, acid-treated fly ash high-temperature insulation billet was obtained.

[0037] Acidified fly ash high-temperature insulation blanks are modified with polyaniline to obtain polyaniline-modified fly ash high-temperature insulation blanks. The specific operation is as follows:

[0038] Weigh 0.075 g of hexadecyltrimethylammonium bromide and stir it evenly with 150 mL of distilled water to obtain a hexadecyltrimethylammonium bromide solution; add 200 mL of distilled water to 10 g of acid-treated high-temperature insulation blank of fly ash (i.e., the mass ratio of acid-treated high-temperature insulation blank of fly ash to hexadecyltrimethylammonium bromide is 1:0.0075), stir evenly, then add the hexadecyltrimethylammonium bromide solution, and react at 75 °C for 1 h; filter the reactants under reduced pressure, wash them with distilled water and dry them to obtain high-temperature insulation blank of fly ash modified with hexadecyltrimethylammonium bromide;

[0039] 7g of aniline, 10g of hexadecyltrimethylammonium bromide-modified high-temperature insulating material from fly ash, and 8g of dodecylbenzenesulfonic acid were added to 200g of distilled water and stirred at room temperature to form an emulsion. 15g of ammonium persulfate (i.e., the mass ratio of hexadecyltrimethylammonium bromide-modified high-temperature insulating material from fly ash, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate was 1:0.7:0.8:1.5) was dissolved in 100g of water and added dropwise to the emulsion. The reaction was carried out continuously at 4℃ for 14h. After the reaction was completed, the material was filtered under reduced pressure, washed with acetone, and dried to obtain polyaniline-modified high-temperature insulating material from fly ash.

[0040] S4. A YSZ / La2O3 composite coating is applied to the surface of polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition. The specific operation is as follows:

[0041] 1.8 g of yttrium-stabilized zirconium oxide powder and 0.1 g of lanthanum oxide powder were dispersed in 300 mL of anhydrous ethanol and homogenized in an ultrasonic bath for 15 min. 0.15 g of dispersant iodine was added (i.e., the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine was 18:1:1.5), and the mixture was ultrasonically treated for 2 h to obtain a YSZ / La2O3 suspension. Using polyaniline-modified fly ash high-temperature insulating blank as the cathode and graphite plate as the anode, the suspension was deposited at 40 V for 8 min.

[0042] After sintering at 800℃ for 6 hours in an argon atmosphere, high-temperature thermal insulation material made from fly ash is obtained.

[0043] Example 2

[0044] S1. Mix 21g of borax and 0.21g of alumina evenly (the mass ratio of borax to alumina is 1:0.01), add 24g of vermiculite and 18g of slag wool, and mix evenly to obtain mixture A; mix 45g of fly ash cenospheres with a particle size of 150-850μm with 18.5g of water glass to obtain mixture B;

[0045] S2. Mix mixture A and mixture B, stir for 25 minutes to form a uniformly mixed mud; after acclimation for 13 hours, press it into a cylindrical sample of φ50mm×50mm under a pressure of 5MPa, then pre-dry it at 120℃ for 13 hours; then calcine it at 900℃ for 4.5 hours to obtain a high-temperature insulating fly ash billet.

[0046] S3. After acidification treatment of the high-temperature insulation blank made of fly ash, the acidified high-temperature insulation blank made of fly ash is obtained. The specific operation is as follows:

[0047] 20g of fly ash high-temperature insulation billet was mixed in 220mL of 2mol / L HCl aqueous solution, and then heated at 80℃ for 8h. The product was filtered and washed with water until neutral. After vacuum drying at 65℃, acid-treated fly ash high-temperature insulation billet was obtained.

[0048] Acidified fly ash high-temperature insulation blanks are modified with polyaniline to obtain polyaniline-modified fly ash high-temperature insulation blanks. The specific operation is as follows:

[0049] Weigh 0.075 g of hexadecyltrimethylammonium bromide and stir it evenly with 175 mL of distilled water to obtain a hexadecyltrimethylammonium bromide solution; add 250 mL of distilled water to 10 g of acid-treated high-temperature insulating fly ash billet (i.e., the mass ratio of acid-treated high-temperature insulating fly ash billet to hexadecyltrimethylammonium bromide is 1:0.0075), stir evenly, then add the hexadecyltrimethylammonium bromide solution, and react at 80 °C for 1.5 h; filter the reactants under reduced pressure, wash them with distilled water and dry them to obtain hexadecyltrimethylammonium bromide modified high-temperature insulating fly ash billet;

[0050] 7g of aniline, 10g of hexadecyltrimethylammonium bromide-modified high-temperature insulating raw material of fly ash and 8g of dodecylbenzenesulfonic acid were added to 220g of distilled water and stirred at room temperature to form an emulsion. 15g of ammonium persulfate (i.e., the mass ratio of hexadecyltrimethylammonium bromide-modified high-temperature insulating raw material of fly ash, aniline, dodecylbenzenesulfonic acid and ammonium persulfate is 1:0.7:0.8:1.5) was dissolved in 120g of water and added dropwise to the emulsion. The reaction was carried out continuously at 5℃ for 13h. After the reaction was completed, the material was filtered under reduced pressure, washed with acetone and dried to obtain polyaniline-modified high-temperature insulating raw material of fly ash.

[0051] S4. A YSZ / La2O3 composite coating is applied to the surface of polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition. The specific operation is as follows:

[0052] 1.8 g of yttrium-stabilized zirconium oxide powder and 0.1 g of lanthanum oxide powder were dispersed in 350 mL of anhydrous ethanol and homogenized using an ultrasonic bath for 18 min. 0.15 g of dispersant iodine was added (i.e., the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine was 18:1:1.5), and the mixture was ultrasonically treated for 2.5 h to obtain a YSZ / La2O3 suspension. Using polyaniline-modified fly ash high-temperature insulating blank as the cathode and graphite plate as the anode, the suspension was deposited at 50 V for 10 min.

[0053] After sintering at 900℃ for 5 hours in an argon atmosphere, high-temperature thermal insulation material made from fly ash is obtained.

[0054] Example 3

[0055] S1. Mix 25g of borax and 0.25g of alumina evenly (the mass ratio of borax to alumina is 1:0.01), add 28g of vermiculite and 21g of slag wool, and mix evenly to obtain mixture A; mix 50g of fly ash cenospheres with a particle size of 150-850μm with 20g of water glass to obtain mixture B;

[0056] S2. Mix mixture A and mixture B, stir for 30 minutes to form a uniformly mixed mud; after acclimation for 14 hours, press it into a cylindrical sample with a diameter of φ50mm×50mm under a pressure of 5MPa, then pre-dry it at 130℃ for 16 hours; then calcine it at 1000℃ for 3 hours to obtain a high-temperature insulating fly ash billet.

[0057] S3. After acidification treatment of the high-temperature insulation blank made of fly ash, the acidified high-temperature insulation blank made of fly ash is obtained. The specific operation is as follows:

[0058] 20g of fly ash high-temperature insulation billet was mixed in 240mL of 3mol / L HCl aqueous solution, and then heated at 85℃ for 9h. The product was filtered and washed with water until neutral. After vacuum drying at 70℃, acid-treated fly ash high-temperature insulation billet was obtained.

[0059] Acidified fly ash high-temperature insulation blanks are modified with polyaniline to obtain polyaniline-modified fly ash high-temperature insulation blanks. The specific operation is as follows:

[0060] Weigh 0.075 g of hexadecyltrimethylammonium bromide and stir it evenly with 200 mL of distilled water to obtain a hexadecyltrimethylammonium bromide solution; add 300 mL of distilled water to 10 g of acid-treated high-temperature insulating material of fly ash (i.e., the mass ratio of acid-treated high-temperature insulating material of fly ash to hexadecyltrimethylammonium bromide is 1:0.0075), stir evenly, then add the hexadecyltrimethylammonium bromide solution, and react at 85 °C for 2 h; filter the reactants under reduced pressure, wash them with distilled water and dry them to obtain hexadecyltrimethylammonium bromide modified high-temperature insulating material of fly ash;

[0061] 7g of aniline, 10g of hexadecyltrimethylammonium bromide-modified high-temperature insulating raw material of fly ash and 8g of dodecylbenzenesulfonic acid were added to 250g of distilled water and stirred at room temperature to form an emulsion. 15g of ammonium persulfate (i.e., the mass ratio of hexadecyltrimethylammonium bromide-modified high-temperature insulating raw material of fly ash, aniline, dodecylbenzenesulfonic acid and ammonium persulfate is 1:0.7:0.8:1.5) was dissolved in 150g of water and added dropwise to the emulsion. The reaction was carried out continuously at 6℃ for 12h. After the reaction was completed, the material was filtered under reduced pressure, washed with acetone and dried to obtain polyaniline-modified high-temperature insulating raw material of fly ash.

[0062] S4. A YSZ / La2O3 composite coating is applied to the surface of polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition. The specific operation is as follows:

[0063] 1.8 g of yttrium-stabilized zirconium oxide powder and 0.1 g of lanthanum oxide powder were dispersed in 400 mL of anhydrous ethanol and homogenized in an ultrasonic bath for 20 min. 0.15 g of dispersant iodine was added (i.e., the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine was 18:1:1.5), and the mixture was ultrasonically treated for 3 h to obtain a YSZ / La2O3 suspension. Using polyaniline-modified fly ash high-temperature insulating blank as the cathode and graphite plate as the anode, the suspension was deposited at 60 V for 12 min.

[0064] After sintering at 1000℃ for 4 hours in an argon atmosphere, high-temperature thermal insulation material made from fly ash is obtained.

[0065] Example 4

[0066] The difference between Example 4 and Example 1 is that in Example 4, 17g of borax and 0.221g of alumina were used, that is, the mass ratio of borax to alumina was 1:0.013.

[0067] Example 5

[0068] The difference between Example 5 and Example 1 is that in Example 5, 17g of borax and 0.255g of alumina were used, that is, the mass ratio of borax to alumina was 1:0.015.

[0069] Example 6

[0070] The difference between Example 6 and Example 1 is that in Example 6, the acid-treated high-temperature insulation blank of fly ash used in S3 is 10g and hexadecyltrimethylammonium bromide is 0.085g, that is, the mass ratio of high-temperature insulation blank of fly ash to hexadecyltrimethylammonium bromide is 1:0.0085.

[0071] Example 7

[0072] The difference between Example 7 and Example 1 is that in Example 7, the acid-treated high-temperature insulation blank of fly ash used in S3 is 10g and hexadecyltrimethylammonium bromide is 0.1g, that is, the mass ratio of high-temperature insulation blank of fly ash to hexadecyltrimethylammonium bromide is 1:0.01.

[0073] Example 8

[0074] The difference between Example 8 and Example 1 is that in Example 8, the acid-treated high-temperature insulation blank of fly ash used in S3 is 10g and hexadecyltrimethylammonium bromide is 0.06g, that is, the mass ratio of high-temperature insulation blank of fly ash to hexadecyltrimethylammonium bromide is 1:0.006.

[0075] Example 9

[0076] The difference between Example 9 and Example 1 is that in Example 9, the acid-treated high-temperature insulation blank of fly ash used in S3 is 10g and hexadecyltrimethylammonium bromide is 0.115g, that is, the mass ratio of high-temperature insulation blank of fly ash to hexadecyltrimethylammonium bromide is 1:0.0115.

[0077] Example 10

[0078] The difference between Example 10 and Example 1 is that in Example 10, the amount of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine used in S4 is 1.9g, that is, the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 19:1:1.6.

[0079] Example 11

[0080] The difference between Example 11 and Example 1 is that in Example 10, the amount of yttrium-stabilized zirconium oxide powder used in S4 is 2g, lanthanum oxide powder is 0.1g, and iodine is 0.17g, that is, the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 20:1:1.7.

[0081] Example 12

[0082] The difference between Example 12 and Example 1 is that in Example 12, the amount of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine used in S4 is 1.7g, that is, the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 17:1:1.4.

[0083] Example 13

[0084] The difference between Example 13 and Example 1 is that in Example 13, the amount of yttrium-stabilized zirconium oxide powder used in S4 is 2.1g, lanthanum oxide powder is 0.1g, and iodine is 0.18g, that is, the mass ratio of yttrium-stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 21:1:1.8.

[0085] Example 14

[0086] The difference between Example 14 and Example 1 is that in Example 14, the amount of hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation blank used in S3 is 10g, aniline is 8g, dodecylbenzenesulfonic acid is 8.5g, and ammonium persulfate is 20g. That is, the mass ratio of the hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation blank, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate is 1:0.8:0.85:2.

[0087] Example 15

[0088] The difference between Example 15 and Example 1 is that in Example 15, the amount of hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation blank used in S3 is 10g, aniline is 9g, dodecylbenzenesulfonic acid is 9g, and ammonium persulfate is 25g, that is, the mass ratio of the hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation blank, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate is 1:0.9:0.9:2.5.

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Example 1 is that no aluminum oxide was added in Comparative Example 1.

[0091] Comparative Example 2

[0092] The difference between Comparative Example 2 and Example 1 is that 17g of borax and 0.085g of alumina were used in Comparative Example 2, that is, the mass ratio of borax to alumina was 1:0.005.

[0093] Comparative Example 3

[0094] The difference between Comparative Example 3 and Example 1 is that 17g of borax and 0.34g of alumina were used in Comparative Example 3, that is, the mass ratio of borax to alumina was 1:0.02.

[0095] Comparative Example 4

[0096] The difference between Comparative Example 4 and Example 1 is that no slag wool was added in Comparative Example 4.

[0097] Comparative Example 5

[0098] The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 did not have a YSZ / La2O3 composite coating.

[0099] Comparative Example 6

[0100] The difference between Comparative Example 6 and Example 1 is that no polyaniline modification was performed in Comparative Example 6.

[0101] Performance testing

[0102] I. The room temperature compressive strength of the fired specimens was measured using a YAW-1000D microcomputer-controlled pressure testing machine according to GB / T 5072-2008. The results are shown in Table 1.

[0103] II. The thermal conductivity of the sample after firing at 300℃ was measured using a flat plate thermal conductivity meter according to YB / T 4130-2005. The results are shown in Table 1.

[0104] The specific test results are as follows:

[0105] Table 1 Performance Test Results

[0106]

[0107]

[0108] As can be seen from the test results in Table 1, the high-temperature thermal insulation material and its preparation method provided in this application produce a high room temperature compressive strength, indicating that the high-temperature thermal insulation material provided in this application has strong mechanical properties; the low thermal conductivity indicates that it has excellent thermal insulation capabilities.

[0109] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a high temperature thermal insulation material from fly ash, characterized in that: Includes the following steps: S1. Mix 17-25 parts of borax and 0.17-0.25 parts of alumina evenly by weight, then add 20-28 parts of vermiculite and 15-21 parts of slag wool, and mix evenly to obtain mixture A; mix 40-50 parts of fly ash cenospheres with 15-20 parts of water glass to obtain mixture B; S2. Mix mixture A and mixture B, stir for 20-30 minutes, then pre-dry at 110-130℃ for 10-16 hours; then calcine at 800-1000℃ for 3-6 hours to obtain high-temperature insulating fly ash billet; S3. After acidification treatment of the high-temperature insulation blank of fly ash, an acidified high-temperature insulation blank of fly ash is obtained; the acidified high-temperature insulation blank of fly ash is modified by polyaniline to obtain polyaniline modified high-temperature insulation blank of fly ash. S4. A YSZ / La2O3 composite coating is applied to the surface of polyaniline-modified fly ash high-temperature insulation blank by electrophoretic deposition, and then sintered at 800-1000℃ for 4-6 hours in an argon atmosphere to obtain fly ash high-temperature insulation material. The process of coating the surface of polyaniline-modified fly ash high-temperature insulation blank with a YSZ / La2O3 composite coating by electrophoretic deposition includes the following steps: Yttrium-stabilized zirconium oxide powder and lanthanum oxide powder were dispersed in anhydrous ethanol and homogenized using an ultrasonic bath for 15-20 min. A dispersant was added, and the mixture was ultrasonically treated for 2-3 h to obtain a YSZ / La2O3 suspension. A polyaniline-modified fly ash high-temperature insulating blank was used as the cathode, and a graphite plate was used as the anode. The suspension was deposited at a voltage of 40-60V for 8-12 min.

2. The method for preparing fly ash high temperature insulation material according to claim 1, characterized in that: The particle size of the fly ash cenospheres is 150-850 μm.

3. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 1, characterized in that: The acidification treatment of high-temperature insulating fly ash billets described in S3 includes the following steps: The high-temperature insulating material of fly ash is mixed in dilute acid and then heated at 75-85℃ for 7-9 hours. The product is filtered and washed with water until neutral. After vacuum drying, the acid-treated high-temperature insulating material of fly ash is obtained.

4. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 3, characterized in that: The dilute acid is a 1-3 mol / L HCl aqueous solution; the solid-liquid ratio of the fly ash high-temperature insulating billet to the dilute acid is 1:10-12 g / mL.

5. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 1, characterized in that: The polyaniline-modified fly ash high-temperature insulating blank described in S3 includes the following steps: Weigh hexadecyltrimethylammonium bromide and stir it evenly with distilled water to obtain a hexadecyltrimethylammonium bromide solution; add distilled water to acidified fly ash high-temperature insulation billet and stir evenly, then add hexadecyltrimethylammonium bromide solution and react at 75-85℃ for 1-2 hours; filter the reactants under reduced pressure, wash and dry them to obtain hexadecyltrimethylammonium bromide modified fly ash high-temperature insulation billet; Aniline, hexadecyltrimethylammonium bromide-modified high-temperature insulating material from fly ash, and dodecylbenzene sulfonic acid were added to distilled water and stirred at room temperature to form an emulsion. Ammonium persulfate was dissolved in water and added dropwise to the emulsion. The reaction was carried out continuously at 4-6℃ for 12-14 hours. After the reaction was completed, the material was filtered under reduced pressure, washed, and dried to obtain polyaniline-modified high-temperature insulating material from fly ash.

6. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 5, characterized in that: The mass ratio of the acidified fly ash high-temperature insulating billet to cetyltrimethylammonium bromide is 1:0.0075-0.

01.

7. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 5, characterized in that: The mass ratio of the hexadecyltrimethylammonium bromide modified fly ash high-temperature insulating blank, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate is 1:0.7-0.9:0.8-0.9:1.5-2.

5.

8. The method for preparing a high-temperature thermal insulation material from fly ash according to claim 1, characterized in that: The dispersant is iodine; the mass ratio of yttrium oxide stabilized zirconium oxide powder, lanthanum oxide powder, and iodine is 18-20:1:1.5-1.7.

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