A fire-resistant inorganic fiber wool board and a method for manufacturing the same

Abstract

The application provides a fire-resistant inorganic fiber cotton board and a preparation method thereof, and belongs to the technical field of refractory materials. The preparation method comprises the following steps: loading ammonium polyphosphate on sepiolite powder after acid immersion treatment by phosphoric acid, drying and crushing to obtain product A; reacting DOPO with gamma-aminopropyl triethoxysilane, stirring and dissolving to obtain product B; hydrolyzing and polycondensing methyltrimethoxysilane and diethanolamine, adding dibutyltin dilaurate to continue the reaction to obtain product C; combining and configuring raw materials including sodium silicate, potassium silicate, product A, product B and product C into a curing liquid; forming inorganic fiber cotton board roughcast by melting and centrifuging slag into cotton and wet forming; spraying the curing liquid on the inorganic fiber cotton board roughcast after vacuum dewatering, and drying to obtain the fire-resistant inorganic fiber cotton board. The inorganic fiber cotton board is sprayed on both sides by using a new curing liquid, so that the fireproof performance is high, and the mechanical properties of the inorganic fiber cotton board are enhanced.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, and in particular to a refractory inorganic fiber cotton board and its preparation method. Background Technology

[0002] Inorganic fiber cotton, also known as mineral fiber cotton, is a Class A fire-resistant material made primarily of mineral fibers such as rock wool, slag wool, and glass wool. This type of material has advantages such as non-combustibility upon contact with fire, low thermal conductivity, stable chemical properties, and a long service life, making it a recognized ideal insulation material both domestically and internationally. The production process of inorganic fiber cotton typically involves melting ores and coke in a specific ratio at high temperatures, followed by fiber formation through centrifugal or spin-drying processes. Its main components include silicon dioxide, aluminum oxide, and calcium oxide.

[0003] Inorganic fiber cotton boards are manufactured by processing inorganic fiber cotton into boards with certain strength and dimensional stability. They are widely used in the construction industry, such as for exterior wall insulation, roof insulation, interior fireproof partitions, and acoustic ceilings. In addition, they are used in industrial applications such as high-temperature equipment protection, cold storage insulation, and cleanrooms. In transportation infrastructure, inorganic fiber cotton boards can be used for tunnel fireproof lining, subway noise reduction, and thermal insulation and fireproofing in shipbuilding and aerospace. However, inorganic fiber cotton boards also have some problems in practical applications, such as high moisture absorption which may lead to sagging and detachment, and low tensile strength which may cause them to peel off from walls. Nevertheless, their excellent fireproof, thermal insulation, and sound insulation properties make them irreplaceable in the construction and industrial fields.

[0004] Traditional inorganic fiber cotton boards are mostly bonded with phenolic resin, which poses a risk of formaldehyde release. To overcome this problem, industry researchers are exploring new manufacturing processes for inorganic fiber cotton boards. Summary of the Invention

[0005] To address the problems mentioned in the background art, the fire-resistant inorganic fiber cotton board provided by this invention uses a new curing liquid to spray the inorganic fiber cotton board blank on both sides, which not only has high fire resistance but also enhances the mechanical properties of the inorganic fiber cotton board.

[0006] Specifically:

[0007] A method for preparing a fire-resistant inorganic fiber cotton board, comprising the following steps:

[0008] Step 1: After leaching sepiolite powder with phosphoric acid, load it with ammonium polyphosphate, dry and pulverize it to obtain product A;

[0009] Step 2: React DOPO with γ-aminopropyltriethoxysilane, stir to dissolve, and obtain product B;

[0010] Step 3: Hydrolyze and condense methyltrimethoxysilane with diethanolamine, add dibutyltin dilaurate to continue the reaction, and obtain product C;

[0011] Step 4: Prepare a curing solution by combining the following raw materials: 40-50 parts sodium silicate, 15-20 parts potassium silicate, 3-8 parts polyvinyl alcohol, 10-15 parts modified attapulgite powder, 5-10 parts product A, 2-5 parts nano silica sol, 0.5-1.2 parts organosilicon hydrophobic agent, 1-2 parts product B, 3-5 parts product C, and 4-6 parts HBP-NH2.

[0012] The curing solution preparation steps include:

[0013] S1. Dissolve sodium silicate and potassium silicate in deionized water to prepare a solution with a solid content of 35%-40%, adjust the pH to 10.5 with sodium citrate, and allow the pre-reaction to proceed for 30-35 minutes.

[0014] S2, then add nano silica sol, product B, and product C, and heat to 50-52℃ and stir to react for 1-1.2 hours;

[0015] S3. Continue adding polyvinyl alcohol and mix for 15-20 minutes.

[0016] S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly. Add organosilicon hydrophobic agent and mature at 40-42℃ for 2-2.5 hours.

[0017] S5. Pass through a 200-mesh sieve, maintain the temperature at 20-25℃, and adjust the viscosity to 4000-4500 mPa·s using a rheometer to prepare a curing liquid.

[0018] Step 5: Melt and centrifuge the slag into cotton, then wet-form it to obtain a rough blank of inorganic fiber cotton board;

[0019] Step 6: After vacuum dehydration, the inorganic fiber cotton board blank obtained in Step 5 is sprayed with the curing liquid prepared in Step 4, and then dried to obtain a fire-resistant inorganic fiber cotton board.

[0020] Further, in step one, sepiolite powder and 10% wt phosphoric acid are mixed at a solid-liquid ratio of 1:(7-8), stirred at 68-72℃ and 450-500 rpm for 3-3.5 hours, and then filtered to collect the filter residue; the filter residue is mixed with ammonium polyphosphate at a mass ratio of (3-3.3):1, ball-milled for 2-3 hours, dried at 100-105℃ to constant weight, pulverized and sieved to obtain product A.

[0021] Further, in step two, DOPO and γ-aminopropyltriethoxysilane are mixed at a mass ratio of (1.2-1.4):1, heated to 120-125℃ and stirred for 4-4.5 h under nitrogen protection. After the reaction is completed, the reaction product is dissolved in anhydrous ethanol at a mass ratio of 1:(1.5-2) to obtain product B.

[0022] Further, in step three, methyltrimethoxysilane and diethanolamine are mixed at a mass ratio of (3.8-4):1 and hydrolyzed and polycondensed at 60-62℃ for 3-3.5h. Then, 0.5%wt dibutyltin dilaurate is added, and the temperature is raised to 80-82℃ to continue the reaction for 1-1.5h to obtain product C.

[0023] Furthermore, in step five, the mass ratio of calcium oxide to silicon dioxide in the slag is (1-1.2):1.

[0024] Furthermore, in step five, the cotton fibers have a diameter of 4-6 μm and are wet-formed to a thickness of 50 mm to form an inorganic fiber cotton board blank.

[0025] Further, in step six, vacuum dehydration is carried out until the moisture content is 45%-50%; the inorganic fiber cotton board blank is sprayed with curing liquid on both sides, with a coating amount of 1-1.2 kg / m² and a penetration time of 100-120 s.

[0026] Furthermore, the drying process in step six includes: first, heating to the initial solidification stage at 140-160℃ and holding for 10-15 minutes; then heating to the crystallization stage at 180-200℃ and holding for 20-25 minutes; and finally heating to the final solidification stage at 220℃ and holding for 5-8 minutes.

[0027] On the other hand, the present invention also provides a fire-resistant inorganic fiber cotton board, which is prepared by the above-described preparation method.

[0028] Product A is phosphoric acid activated sepiolite powder. Its surface phosphate groups can react with silicates to form Si-OP covalent bonds, forming a heat-resistant framework.

[0029] Product B is silanized DOPO, whose rigid benzo[a] ring can be embedded in the silicate network, restricting the thermal motion of the molecular chain.

[0030] Product C is a hyperbranched polysiloxane with a three-dimensional network structure that fills the silicate pores. During film formation, it can form a dense and solidified film that physically blocks the volatilization of moisture and small molecule organic matter.

[0031] Compared with the prior art, the beneficial features of the present invention are as follows:

[0032] 1. The fire-resistant inorganic fiber cotton board of the present invention, through the low molecular weight characteristics (2-5nm) of the product C, penetrates into the micropores of mineral wool fibers, and the terminal silanol groups (-SiOH) bond with the hydroxyl groups on the fiber surface to form Si-O-Si chemical anchoring points; in addition, nano-silica sol fills the fiber gaps, and together with HBPSi, forms a "rigid core-flexible shell" structure; at the same time, modified attapulgite bridges between fibers, and enhances the interfacial bonding force through mechanical interlocking and hydrogen bond adsorption; through the synergistic effect of the three, the bonding strength of the inorganic fiber cotton board is improved, thereby improving the compressive strength of the inorganic fiber cotton board.

[0033] 2. In the fire-resistant inorganic fiber cotton board of the present invention, product B decomposes upon heating at 200-300℃, releasing phosphorus and oxygen free radicals, which quench the H· / OH· free radicals released by the thermal decomposition of mineral wool, interrupting the combustion chain reaction, thereby suppressing gas-phase combustion, reducing thermal damage to mineral wool, and preserving the strength of the fiber skeleton; furthermore, in product A at 300-600℃, Mg²⁺… + It reacts with the decomposition products of ammonium polyphosphate (polyphosphoric acid) to form magnesium phosphate glass (high melting point), and at the same time catalyzes the silicate ceramicization of the mineral wool surface to form a continuous heat insulation layer. This layer works synergistically with the rigid structure of DOPO-Si to suppress thermal deformation and achieve fireproofing. Through the different fireproofing mechanisms of the system components, the fireproofing effect is even better.

[0034] 3. The fire-resistant inorganic fiber cotton board of the present invention forms a cross-linked hydrophobic film on the surface of mineral wool through the product C three-dimensional network, and the organosilicon hydrophobic agent fills the gaps in the product C three-dimensional network. The two work together to improve the hydrophobic properties of the inorganic fiber cotton board.

[0035] 4. The fire-resistant inorganic fiber cotton board of the present invention, on the one hand, the -NH2 at the end of HBP-NH2 in the component can react with Al-OH on the surface of mineral wool fiber to generate Al-OC covalent bonds to replace traditional physical adsorption, and the branched structure of HBP-NH2 deforms and absorbs energy when subjected to force, inhibiting crack propagation, thereby further enhancing the mechanical properties of the inorganic fiber cotton board. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0037] To facilitate implementation of this invention by those skilled in the art, some of the reagents used are described below:

[0038] Sepiolite powder: Lingshou County Malin Mineral Products Processing Plant;

[0039] Ammonium polyphosphate: Zhengzhou Jiajie Chemical Products Co., Ltd.;

[0040] DOPO: Hubei Shineng Chemical Technology Co., Ltd.

[0041] γ-Aminopropyltriethoxysilane: Jiangsu Bosite Chemical Technology Co., Ltd.;

[0042] Methyltrimethoxysilane: Shandong Qiangsen Chemical Co., Ltd.;

[0043] Diethanolamine: Shandong Kejian Chemical Co., Ltd.;

[0044] Dibutyltin dilaurate: Shandong Huian Chemical Co., Ltd.;

[0045] Sodium silicate: Jinan Yuanyi Environmental Protection Technology Co., Ltd.;

[0046] Potassium silicate: Jinan Yuanyi Environmental Protection Technology Co., Ltd.;

[0047] Nano-silica sol: Hangzhou Jiupeng New Materials Co., Ltd.;

[0048] Polyvinyl alcohol: Nantong Changchen Chemical Co., Ltd.;

[0049] Modified attapulgite powder: Lingshou County Malin Mineral Products Processing Plant;

[0050] HBP-NH2: Boltorn™ H2O;

[0051] Organosilicon water-repellent agent: Potassium methylsilicate, Shandong Yuxing Fine Chemical Co., Ltd.

[0052] Slag: The mass ratio of calcium oxide to silicon dioxide in slag is 1.2:1. Lingshou County Malin Mineral Products Processing Plant.

[0053] Example 1

[0054] A fire-resistant inorganic fiber cotton board, the preparation steps of which include:

[0055] Step 1: Mix sepiolite powder and 10%wt phosphoric acid at a solid-liquid ratio of 1:7, stir at 68℃ and 450rpm for 3h, then filter and collect the filter residue; mix the filter residue with ammonium polyphosphate at a mass ratio of 3:1, ball mill for 2h, dry at 100℃ to constant weight, pulverize and sieve to obtain product A;

[0056] Step 2: Mix DOPO and γ-aminopropyltriethoxysilane at a mass ratio of 1.2:1, heat to 120°C and stir for 4 hours under nitrogen protection. After the reaction is complete, dissolve the reaction product in anhydrous ethanol at a mass ratio of 1:1.5 to obtain product B.

[0057] Step 3: Mix methyltrimethoxysilane and diethanolamine at a mass ratio of 3.8:1, and hydrolyze and polycondense at 60°C for 3 hours. Then add 0.5%wt dibutyltin dilaurate, raise the temperature to 80°C and continue the reaction for 1 hour to obtain product C.

[0058] Step 4: Prepare a curing solution by combining the following raw materials: 40 parts sodium silicate, 15 parts potassium silicate, 8 parts polyvinyl alcohol, 15 parts modified attapulgite powder, 10 parts product A, 5 parts nano silica sol, 1.2 parts organosilicon hydrophobic agent, 2 parts product B, 5 parts product C, and 6 parts HBP-NH2.

[0059] The curing solution preparation steps include:

[0060] S1. Dissolve sodium silicate and potassium silicate in deionized water to prepare a solution with a solid content of 35%. Adjust the pH to 10.5 with sodium citrate and allow it to react for 30-35 minutes.

[0061] S2, then add nano silica sol, product B, and product C, and heat to 50°C and stir to react for 1 hour;

[0062] S3. Continue adding polyvinyl alcohol and mix for 15 minutes.

[0063] S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly. Add organosilicon water-repellent agent and aging at 40℃ for 2 hours.

[0064] S5. Pass through a 200-mesh sieve, maintain the temperature at 20℃, and adjust the viscosity to 4000 mPa·s using a rheometer to prepare a curing liquid.

[0065] Step 5: Melt and centrifuge the slag into cotton with a fiber diameter of 4-6μm, and wet-form it into a board with a thickness of 50mm to obtain an inorganic fiber cotton board blank.

[0066] Step Six: The inorganic fiber cotton board blank obtained in Step Five is vacuum dehydrated to a moisture content of 45%. The curing liquid prepared in Step Four is sprayed onto both sides of the inorganic fiber cotton board blank at a coating amount of 1 kg / m² and a penetration time of 100 s. Then it is sent to the tunnel kiln in Zone Three for drying. First, the temperature is raised to the initial setting stage of 140°C and held for 10 min. Then, the temperature is raised to the crystallization stage of 180°C and held for 25 min. Finally, the temperature is raised to the final setting stage of 220°C and held for 5 min. After cooling, the refractory inorganic fiber cotton board is obtained.

[0067] Example 2

[0068] A fire-resistant inorganic fiber cotton board, the preparation steps of which include:

[0069] Step 1: Mix sepiolite powder with 10%wt phosphoric acid at a solid-liquid ratio of 1:8, stir at 72℃ and 500rpm for 3.5h, then filter and collect the filter residue; mix the filter residue with ammonium polyphosphate at a mass ratio of 3.3:1, ball mill for 3h, dry at 105℃ to constant weight, pulverize and sieve to obtain product A;

[0070] Step 2: Mix DOPO and γ-aminopropyltriethoxysilane at a mass ratio of 1.4:1, heat to 125°C and stir for 4.5 h under nitrogen protection. After the reaction is complete, dissolve the reaction product in anhydrous ethanol at a mass ratio of 1:2 to obtain product B.

[0071] Step 3: Mix methyltrimethoxysilane and diethanolamine at a mass ratio of 4:1, and hydrolyze and polycondense at 62°C for 3.5 h. Then add 0.5%wt dibutyltin dilaurate, raise the temperature to 82°C and continue the reaction for 1.5 h to obtain product C.

[0072] Step 4: Combine the raw materials containing 50 parts sodium silicate, 20 parts potassium silicate, 8 parts polyvinyl alcohol, 15 parts modified attapulgite powder, 5 parts product A, 5 parts nano silica sol, 1.2 parts organosilicon hydrophobic agent, 1 part product B, 3 parts product C, and 6 parts HBP-NH2 to prepare a curing solution.

[0073] The curing solution preparation steps include:

[0074] S1. Dissolve sodium silicate and potassium silicate in deionized water to prepare a solution with a solid content of 40%. Adjust the pH to 10.5 with sodium citrate and allow it to react for 35 minutes.

[0075] S2, then add nano silica sol, product B, and product C, and heat to 52°C and stir for 1.2 h;

[0076] S3. Continue adding polyvinyl alcohol and mix for 20 minutes.

[0077] S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly. Add organosilicon hydrophobic agent and cure at 42℃ for 2.5h.

[0078] S5. Pass through a 200-mesh sieve, maintain the temperature at 25℃, and adjust the viscosity to 4500 mPa·s using a rheometer to prepare a curing liquid.

[0079] Step 5: Melt and centrifuge the slag into cotton with a fiber diameter of 4-6μm, and wet-form it into a board with a thickness of 50mm to obtain an inorganic fiber cotton board blank.

[0080] Step Six: The inorganic fiber cotton board blank obtained in Step Five is vacuum dehydrated to a moisture content of 50%. The curing liquid prepared in Step Four is sprayed onto both sides of the inorganic fiber cotton board blank at a coating amount of 1.2 kg / m² and a penetration time of 120 s. Then it is sent to the tunnel kiln in Zone Three for drying. First, the temperature is raised to the initial setting stage of 160°C and held for 10 min. Then, the temperature is raised to the crystallization stage of 200°C and held for 20 min. Finally, the temperature is raised to the final setting stage of 220°C and held for 8 min. After cooling, the refractory inorganic fiber cotton board is obtained.

[0081] Example 3

[0082] A fire-resistant inorganic fiber cotton board, the preparation steps of which include:

[0083] Step 1: Mix sepiolite powder with 10%wt phosphoric acid at a solid-liquid ratio of 1:8, stir at 70℃ and 500rpm for 3.5h, then filter and collect the filter residue; mix the filter residue with ammonium polyphosphate at a mass ratio of 3.3:1, ball mill for 2h, dry at 105℃ to constant weight, pulverize and sieve to obtain product A;

[0084] Step 2: Mix DOPO and γ-aminopropyltriethoxysilane at a mass ratio of 1.4:1, heat to 120°C and stir for 4.5 h under nitrogen protection. After the reaction is complete, dissolve the reaction product in anhydrous ethanol at a mass ratio of 1:1.5 to obtain product B.

[0085] Step 3: Mix methyltrimethoxysilane and diethanolamine at a mass ratio of 3.8:1, and hydrolyze and polycondense at 60°C for 3.5 h. Then add 0.5%wt dibutyltin dilaurate, raise the temperature to 80°C and continue the reaction for 1.5 h to obtain product C.

[0086] Step 4: Prepare a curing solution by combining the following raw materials: 50 parts sodium silicate, 20 parts potassium silicate, 3 parts polyvinyl alcohol, 10 parts modified attapulgite powder, 10 parts product A, 2 parts nano silica sol, 0.5 parts organosilicon hydrophobic agent, 2 parts product B, 5 parts product C, and 4 parts HBP-NH2.

[0087] The curing solution preparation steps include:

[0088] S1. Dissolve sodium silicate and potassium silicate in deionized water to prepare a solution with a solid content of 40%. Adjust the pH to 10.5 with sodium citrate and allow it to react for 30 minutes.

[0089] S2, then add nano silica sol, product B, and product C, and heat to 50°C and stir for 1.2 h;

[0090] S3. Continue adding polyvinyl alcohol and mix for 20 minutes.

[0091] S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly. Add organosilicon hydrophobic agent and cure at 40℃ for 2.5h.

[0092] S5. Pass through a 200-mesh sieve, maintain the temperature at 25℃, and adjust the viscosity to 4500 mPa·s using a rheometer to prepare a curing liquid.

[0093] Step 5: Melt and centrifuge the slag into cotton with a fiber diameter of 4-6μm, and wet-form it into a board with a thickness of 50mm to obtain an inorganic fiber cotton board blank.

[0094] Step Six: The inorganic fiber cotton board blank obtained in Step Five is vacuum dehydrated to a moisture content of 47%. The curing liquid prepared in Step Four is sprayed onto both sides of the inorganic fiber cotton board blank at a coating amount of 1.2 kg / m² and a penetration time of 120 s. Then it is sent to the tunnel kiln in Zone Three for drying. First, the temperature is raised to the initial setting stage of 150°C and held for 15 min. Then, the temperature is raised to the crystallization stage of 200°C and held for 25 min. Finally, the temperature is raised to the final setting stage of 220°C and held for 5 min. After cooling, the refractory inorganic fiber cotton board is obtained.

[0095] The fire-resistant inorganic fiber cotton boards obtained in Examples 1-3 were subjected to the following tests to verify their product performance.

[0096] 1. Perpendicular tensile strength: Determined according to the method in GB / T 30804-2014 "Determination of Perpendicular Tensile Strength of Thermal Insulation Products for Buildings";

[0097] 2. Compressive strength: The compressive strength was tested in accordance with GB / T 13480-2014 "Determination of compressive properties of thermal insulation products for building".

[0098] 3. Moisture absorption rate: Cut the inorganic fiber cotton board into samples (100mm×100mm×50mm), dry them at 110℃ to a constant weight m1, place them in a sealed container at 50℃ / 95% relative humidity, and weigh them m2 after 96 hours. Calculate the moisture absorption rate according to the following formula:

[0099] Moisture absorption rate (%) = (m2-m1) / m1×100;

[0100] 4. Fire resistance test: The test shall be conducted in accordance with the method specified in GB / T 8624-2012 "Classification of Combustion Performance of Building Materials and Products".

[0101] The test results are shown in the table below.

[0102] Example 1 92 104 2.1 Grade A Example 2 95 102 1.3 Grade A Example 3 91 105 1.6 Grade A

[0103] The experimental results above show that the inorganic fiber cotton board prepared in the embodiments of the present invention exhibits excellent mechanical properties, fire resistance, and hydrophobic properties.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a fire-resistant inorganic fiber cotton board, characterized in that, The steps include: Step 1: After leaching sepiolite powder with phosphoric acid, load it with ammonium polyphosphate, dry and pulverize it to obtain product A; Step 2: React DOPO with γ-aminopropyltriethoxysilane, stir to dissolve, and obtain product B; Step 3: Hydrolyze and condense methyltrimethoxysilane with diethanolamine, add dibutyltin dilaurate to continue the reaction, and obtain product C; Step 4: Prepare a curing solution by combining the following raw materials: 40-50 parts sodium silicate, 15-20 parts potassium silicate, 3-8 parts polyvinyl alcohol, 10-15 parts modified attapulgite powder, 5-10 parts product A, 2-5 parts nano silica sol, 0.5-1.2 parts organosilicon hydrophobic agent, 1-2 parts product B, 3-5 parts product C, and 4-6 parts HBP-NH2. The curing solution preparation steps include: S1. Dissolve sodium silicate and potassium silicate in deionized water to prepare a solution with a solid content of 35%-40%, adjust the pH to 10.5 with sodium citrate, and allow the pre-reaction to proceed for 30-35 minutes. S2, then add nano silica sol, product B, and product C, and heat to 50-52℃ and stir to react for 1-1.2 hours; S3. Continue adding polyvinyl alcohol and mix for 15-20 minutes. S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly. Add organosilicon hydrophobic agent and mature at 40-42℃ for 2-2.5 hours. S5. Pass through a 200-mesh sieve, control the temperature at 20-25℃, and adjust the viscosity to 4000-4500 mPa·s using a rheometer to prepare a curing liquid; Step 5: Melt and centrifuge the slag into cotton, then wet-form it to obtain a rough blank of inorganic fiber cotton board; Step 6: After vacuum dehydration, the inorganic fiber cotton board blank obtained in Step 5 is sprayed with the curing liquid prepared in Step 4, and then dried to obtain a fire-resistant inorganic fiber cotton board.

2. The preparation method according to claim 1, characterized in that, In step one, sepiolite powder and 10% wt phosphoric acid are mixed at a solid-liquid ratio of 1:(7-8) and stirred at 68-72℃ and 450-500 rpm for 3-3.5 hours. The mixture is then filtered and the residue is collected. The residue is mixed with ammonium polyphosphate at a mass ratio of (3-3.3):1, ball-milled for 2-3 hours, dried at 100-105℃ to constant weight, pulverized and sieved to obtain product A.

3. The preparation method according to claim 1, characterized in that, In step two, DOPO and γ-aminopropyltriethoxysilane are mixed at a mass ratio of (1.2-1.4):1 and heated to 120-125℃ under nitrogen protection and stirred for 4-4.5 hours. After the reaction is completed, the reaction product is dissolved in anhydrous ethanol at a mass ratio of 1:(1.5-2) to obtain product B.

4. The preparation method according to claim 1, characterized in that, In step three, methyltrimethoxysilane and diethanolamine are mixed at a mass ratio of (3.8-4):1 and hydrolyzed and polycondensed at 60-62℃ for 3-3.5h. Then, 0.5%wt dibutyltin dilaurate is added, and the temperature is raised to 80-82℃ to continue the reaction for 1-1.5h to obtain product C.

5. The preparation method according to claim 1, characterized in that, The mass ratio of calcium oxide to silicon dioxide in the slag of step five is (1-1.2):

1.

6. The preparation method according to claim 1, characterized in that, In step five, the cotton fibers have a diameter of 4-6μm and are wet-formed to a thickness of 50mm to form an inorganic fiber cotton board blank.

7. The preparation method according to claim 1, characterized in that, In step six, vacuum dehydration is carried out until the moisture content is 45%-50%; the inorganic fiber cotton board blank is sprayed with curing liquid on both sides, with a coating amount of 1-1.2 kg / m² and a penetration time of 100-120 s.

8. The preparation method according to claim 1, characterized in that, The drying process in step six includes: first, heating to the initial solidification stage at 140-160℃ and holding for 10-15 minutes; then heating to the crystallization stage at 180-200℃ and holding for 20-25 minutes; finally, heating to the final solidification stage at 220℃ and holding for 5-8 minutes.

9. A fire-resistant inorganic fiber cotton board, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.