Fire-resistant inorganic fiber cotton board and preparation method thereof

Abstract

The invention provides a fire-resistant inorganic fiber cotton board and a preparation method thereof, and belongs to the technical field of fire-resistant materials. The preparation method comprises the following steps: carrying out acid leaching treatment on sepiolite powder by using phosphoric acid, loading ammonium polyphosphate, drying and crushing to obtain a product A; enabling DOPO to react with gamma-aminopropyltriethoxysilane, and stirring and dissolving to obtain a product B; methyltrimethoxysilane and diethanol amine are subjected to hydrolytic polycondensation, dibutyltin dilaurate is added for continuous reaction, and a product C is obtained; combining raw materials including sodium silicate, potassium silicate, the product A, the product B, the product C and the like to prepare a curing liquid; melting and centrifuging the slag into cotton, and carrying out wet forming to obtain an inorganic fiber cotton plate rough blank; and the inorganic fiber cotton board rough blank is subjected to vacuum dehydration, then a curing liquid is sprayed, and the fireproof inorganic fiber cotton board is obtained after drying. The inorganic fiber cotton board is subjected to double-sided spraying by adopting the new curing liquid, so that the fireproof performance is high, and the mechanical property of the inorganic fiber cotton board can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory materials, in particular to a refractory inorganic fiber cotton board and a preparation method thereof. Background Art

[0002] Inorganic fiber wool, also known as mineral fiber wool, is a Class A fireproof material made primarily from mineral fibers such as rock wool, slag wool, and glass wool. This material boasts advantages such as non-combustibility, low thermal conductivity, stable chemical properties, and a long service life, making it recognized both domestically and internationally as an ideal thermal insulation material. The production process typically involves melting ore and coke in appropriate proportions at high temperatures, then forming the fibers through centrifugal or spinneret processes. Its main components include silicon dioxide, aluminum oxide, and calcium oxide.

[0003] Inorganic fiber wool board is formed by processing inorganic fiber wool into sheets with a certain strength and dimensional stability. It is widely used in the construction industry, such as exterior wall insulation, roof insulation, interior fireproof partitions, and acoustic ceilings. It is also used in the industrial sector for high-temperature equipment protection, cold storage insulation, and clean workshops. In transportation infrastructure, inorganic fiber wool board can be used for tunnel fire lining, subway noise reduction, and thermal insulation and fire protection in ships and aerospace. However, inorganic fiber wool board has some practical problems, such as high moisture absorption, which may cause sagging and shedding, and low tensile strength, which may cause it to peel from the wall. Despite this, its excellent fire resistance, thermal insulation, and sound insulation properties make it 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 also exploring new inorganic fiber cotton board preparation processes. Summary of the Invention

[0005] In order to solve the problems mentioned in the background technology, the fire-resistant inorganic fiber cotton board provided by the present invention adopts a new curing liquid to spray the inorganic fiber cotton board rough blank on both sides, which not only has high fire resistance but also can enhance 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: treating sepiolite powder with phosphoric acid, loading ammonium polyphosphate, drying and crushing to obtain product A;

[0009] Step 2: reacting DOPO with γ-aminopropyltriethoxysilane, stirring and dissolving to obtain product B;

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

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

[0012] Step 5: Melting and centrifuging the slag into cotton, and wet forming the cotton to obtain a rough inorganic fiber cotton board;

[0013] Step 6: vacuum dehydrate the inorganic fiber cotton board rough blank obtained in step 5, spray the solidifying liquid prepared in step 4, and then dry it to obtain a fire-resistant inorganic fiber cotton board.

[0014] Furthermore, in step 1, the sepiolite powder is mixed with 10%wt phosphoric acid in a solid-liquid ratio of 1:(7-8), stirred at 68-72°C and 450-500rpm for 3-3.5 hours, and then the filter residue is collected by filtration; the filter residue is mixed with ammonium polyphosphate in a mass ratio of (3-3.3):1, ball milled for 2-3 hours, dried at 100-105°C to constant weight, crushed and sieved to obtain product A.

[0015] Furthermore, in step 2, DOPO and γ-aminopropyltriethoxysilane are mixed in a mass ratio of (1.2-1.4):1, heated to 120-125°C with stirring under nitrogen protection, and reacted for 4-4.5 hours. After the reaction is completed, the reaction product is dissolved in anhydrous ethanol in a mass ratio of 1:(1.5-2) to obtain product B.

[0016] Furthermore, in step 3, methyltrimethoxysilane and diethanolamine are mixed in a mass ratio of (3.8-4):1, hydrolyzed and polycondensed at 60-62° C. for 3-3.5 hours, and then 0.5% wt dibutyltin dilaurate is added, and the temperature is raised to 80-82° C. and the reaction is continued for 1-1.5 hours to obtain product C.

[0017] Furthermore, the curing liquid preparation step in step 4 includes:

[0018] 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 pre-react for 30-35 minutes;

[0019] S2, then add nano-silica sol, product B, and product C, raise the temperature to 50-52°C, and stir to react for 1-1.2h;

[0020] S3, continue to add polyvinyl alcohol and mix for 15-20 minutes;

[0021] S4. Add modified attapulgite powder, product A, and HBP-NH2 under stirring and mix evenly, add organosilicon water repellent, control the temperature at 40-42°C and mature for 2-2.5h;

[0022] S5. Pass through a 200-mesh sieve, control the temperature at 20-25°C, and adjust the viscosity to 4000-4500 mPa·s using a rheometer to prepare a solidifying liquid.

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

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

[0025] Furthermore, in step six, vacuum dehydration is performed to a moisture content of 45%-50%; and curing liquid is sprayed on both sides of the inorganic fiber cotton board rough blank, 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 140-160°C in the initial setting stage and keeping warm for 10-15 minutes; then heating to 180-200°C in the crystallization stage and keeping warm for 20-25 minutes; finally heating to 220°C in the final setting stage and keeping warm 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-mentioned preparation method.

[0028] Product A is phosphoric acid-activated sepiolite powder, the surface phosphate groups of which can react with silicate to generate Si-OP covalent bonds, forming a heat-resistant skeleton.

[0029] Product B is silanized DOPO, whose rigid benzo 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. When forming a film, it can form a dense solidified film, physically blocking the volatilization of moisture and small molecular organic matter.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The fire-resistant inorganic fiber cotton board of the present invention penetrates into the micropores of mineral wool fibers through the small molecular weight characteristics (2-5nm) of product C, and the terminal silanol group (-SiOH) bonds with the hydroxyl group on the fiber surface to form a Si-O-Si chemical anchor point; in addition, the nano-silica sol fills the fiber gaps and cooperates with HBPSi to form a "rigid core-flexible shell" structure; at the same time, the modified attapulgite bridges between the fibers, and enhances the interfacial bonding force through mechanical interlocking + hydrogen bond adsorption; the synergistic effect of the three enhances the bonding strength of the inorganic fiber cotton board, thereby enhancing 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 is thermally decomposed at 200-300°C to release phosphorus oxide free radicals, which quench the H· / OH· free radicals released by the thermal decomposition of the mineral wool, interrupt the combustion chain reaction, and inhibit gas-phase combustion, reduce thermal damage to the mineral wool, and preserve the fiber skeleton strength. In addition, at 300-600°C, the Mg²⁺ in product A reacts with the decomposition product of ammonium polyphosphate (polyphosphoric acid) to form magnesium phosphate glass (high melting point), which simultaneously catalyzes the silicate ceramicization of the mineral wool surface to form a continuous thermal insulation layer, which synergistically inhibits thermal deformation with the rigid structure of DOPO-Si and has a fire-proof effect. The different fire-proof mechanisms of the system components make the fire-proof effect 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 the mineral wool through the three-dimensional network of product C, and the organosilicon hydrophobic agent fills the gaps in the three-dimensional network of product C. The synergistic effect of the two enhances the hydrophobic properties of the inorganic fiber cotton board.

[0035] 4. In the fire-resistant inorganic fiber cotton board of the present invention, on the one hand, the terminal -NH2 of HBP-NH2 in the component can react with Al-OH on the surface of mineral wool fiber to form Al-OC covalent bond to replace traditional physical adsorption, and the branched structure of HBP-NH2 deforms and absorbs energy when subjected to stress, inhibiting crack propagation and further enhancing the mechanical properties of the inorganic fiber cotton board. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in 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 part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In order to facilitate those skilled in the art to implement the present invention, some of the reagents used are now described:

[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 Bost Chemical Technology Co., Ltd.;

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

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

[0044] Dibutyltin dilaurate: Shandong Hui'an 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™ H20;

[0051] Silicone hydrophobic agent: potassium methyl silicate, Shandong Yuxing Fine Chemical Co., Ltd.

[0052] Slag: The mass ratio of calcium oxide to silicon dioxide in the 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: sepiolite powder and 10% wt phosphoric acid were mixed at a solid-liquid ratio of 1:7, stirred at 68°C and 450 rpm for 3 hours, and then filtered to collect the residue; the residue was mixed with ammonium polyphosphate at a mass ratio of 3:1, ball milled for 2 hours, dried at 100°C to constant weight, crushed and sieved to obtain product A;

[0056] Step 2: DOPO and γ-aminopropyltriethoxysilane were mixed at a mass ratio of 1.2:1, heated to 120°C under nitrogen protection, stirred and reacted for 4 hours, and after the reaction was completed, the reaction product was dissolved in anhydrous ethanol at a mass ratio of 1:1.5 to obtain product B;

[0057] Step 3: Methyltrimethoxysilane and diethanolamine were mixed in a mass ratio of 3.8:1, and hydrolyzed and polycondensed at 60°C for 3 hours. Subsequently, 0.5%wt dibutyltin dilaurate was added, and the temperature was raised to 80°C and the reaction was continued for 1 hour to obtain product C;

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

[0059] The steps for preparing the curing liquid 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 pre-react for 30-35 minutes;

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

[0062] S3, continue to add polyvinyl alcohol and mix for 15 minutes;

[0063] S4, adding modified attapulgite powder, product A, and HBP-NH2 under stirring and mixing evenly, adding silicone water repellent, and controlling the temperature at 40°C for aging for 2 hours;

[0064] S5, pass through a 200 mesh sieve, control the temperature at 20°C, and use a rheometer to adjust the viscosity to 4000 mPa·s to prepare a solidifying liquid

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

[0066] Step 6. Vacuum dehydrate the inorganic fiber cotton board rough blank obtained in step 5 to a moisture content of 45%, and spray the curing liquid prepared in step 4 on both sides of the inorganic fiber cotton board rough blank, with a coating amount of 1kg / m² and a penetration time of 100s; then send it to the three-zone tunnel kiln for drying, first heat it to 140°C in the initial setting stage and keep it warm for 10 minutes; continue to heat it to 180°C in the crystallization stage and keep it warm for 25 minutes; finally heat it to 220°C in the final setting stage and keep it warm for 5 minutes, and cool it to obtain a refractory inorganic fiber cotton board.

[0067] Example 2

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

[0069] Step 1: sepiolite powder and 10% wt phosphoric acid were mixed at a solid-liquid ratio of 1:8, stirred at 72°C and 500 rpm for 3.5 hours, and then filtered to collect the residue; the residue was mixed with ammonium polyphosphate at a mass ratio of 3.3:1, ball milled for 3 hours, dried at 105°C to constant weight, crushed and sieved to obtain product A;

[0070] Step 2: DOPO and γ-aminopropyltriethoxysilane were mixed at a mass ratio of 1.4:1, heated to 125°C under nitrogen protection, stirred and reacted for 4.5 hours. After the reaction was completed, the reaction product was dissolved in anhydrous ethanol at a mass ratio of 1:2 to obtain product B;

[0071] Step 3: Methyltrimethoxysilane and diethanolamine were mixed in a mass ratio of 4:1, and hydrolyzed and polycondensed at 62°C for 3.5 hours. Subsequently, 0.5%wt dibutyltin dilaurate was added, and the temperature was raised to 82°C and the reaction was continued for 1.5 hours to obtain product C;

[0072] Step 4: Prepare a curing solution by combining raw materials including 50 parts of sodium silicate, 20 parts of potassium silicate, 8 parts of polyvinyl alcohol, 15 parts of modified attapulgite powder, 5 parts of product A, 5 parts of nano-silica sol, 1.2 parts of an organosilicon hydrophobic agent, 1 part of product B, 3 parts of product C, and 6 parts of HBP-NH2;

[0073] The steps for preparing the curing liquid include:

[0074] S1. Sodium silicate and potassium silicate were dissolved in deionized water to prepare a solution with a solid content of 40%, and the pH was adjusted to 10.5 with sodium citrate. The solution was pre-reacted for 35 minutes.

[0075] S2, then add nano-silica sol, product B, and product C, raise the temperature to 52°C and stir to react for 1.2h;

[0076] S3, continue to add polyvinyl alcohol and mix for 20 minutes;

[0077] S4, adding modified attapulgite powder, product A, and HBP-NH2 under stirring and mixing evenly, adding silicone hydrophobic agent, and controlling the temperature at 42°C for aging for 2.5 hours;

[0078] S5, pass through a 200 mesh sieve, control the temperature at 25°C, and use a rheometer to adjust the viscosity to 4500 mPa·s to prepare a solidifying liquid

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

[0080] Step 6. Vacuum dehydrate the inorganic fiber cotton board rough blank obtained in step 5 to a moisture content of 50%, and spray the curing liquid prepared in step 4 on both sides of the inorganic fiber cotton board rough blank, with a coating amount of 1.2 kg / m² and a penetration time of 120 s; then send it to the three-zone tunnel kiln for drying, first heat it to 160°C in the initial setting stage and keep it warm for 10 minutes; continue to heat it to 200°C in the crystallization stage and keep it warm for 20 minutes; finally heat it to 220°C in the final setting stage and keep it warm for 8 minutes, and cool it to obtain a refractory inorganic fiber cotton board.

[0081] Example 3

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

[0083] Step 1: sepiolite powder and 10% wt phosphoric acid were mixed at a solid-liquid ratio of 1:8, stirred at 70°C and 500 rpm for 3.5 hours, and then filtered to collect the residue; the residue was mixed with ammonium polyphosphate at a mass ratio of 3.3:1, ball milled for 2 hours, dried at 105°C to constant weight, crushed and sieved to obtain product A;

[0084] Step 2: DOPO and γ-aminopropyltriethoxysilane were mixed at a mass ratio of 1.4:1, heated to 120°C under nitrogen protection, stirred and reacted for 4.5 hours, and after the reaction was completed, the reaction product was dissolved in anhydrous ethanol at a mass ratio of 1:1.5 to obtain product B;

[0085] Step 3: Methyltrimethoxysilane and diethanolamine were mixed in a mass ratio of 3.8:1, and hydrolyzed and polycondensed at 60°C for 3.5 hours. Subsequently, 0.5%wt dibutyltin dilaurate was added, and the temperature was raised to 80°C and the reaction was continued for 1.5 hours to obtain product C;

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

[0087] The steps for preparing the curing liquid include:

[0088] S1. Sodium silicate and potassium silicate were dissolved in deionized water to prepare a solution with a solid content of 40%, and the pH was adjusted to 10.5 with sodium citrate, and pre-reacted for 30 minutes;

[0089] S2, then add nano-silica sol, product B, and product C, raise the temperature to 50°C and stir to react for 1.2h;

[0090] S3, continue to add polyvinyl alcohol and mix for 20 minutes;

[0091] S4, adding modified attapulgite powder, product A, and HBP-NH2 under stirring and mixing evenly, adding silicone water repellent, controlling the temperature at 40°C and aging for 2.5h;

[0092] S5, pass through a 200 mesh sieve, control the temperature at 25°C, and use a rheometer to adjust the viscosity to 4500 mPa·s to prepare a solidifying liquid

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

[0094] Step 6. Vacuum dehydrate the inorganic fiber cotton board rough blank obtained in step 5 to a moisture content of 47%, spray the curing liquid prepared in step 4 on both sides of the inorganic fiber cotton board rough blank, with a coating amount of 1.2 kg / m² and a penetration time of 120 s; then send it to the three-zone tunnel kiln for drying, first heat it to 150°C in the initial setting stage and keep it warm for 15 minutes; continue to heat it to 200°C in the crystallization stage and keep it warm for 25 minutes; finally heat it to 220°C in the final setting stage and keep it warm for 5 minutes, and cool it to obtain a refractory inorganic fiber cotton board.

[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. Tensile strength perpendicular to the surface: Determined according to the method in GB / T 30804-2014 "Determination of tensile strength perpendicular to the surface of thermal insulation products for building";

[0097] 2. Compression strength: Refer to GB / T 13480-2014 "Determination of compression properties of thermal insulation products for building use" to test compression strength;

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

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

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

[0101] The test results are shown in the following table

[0102] Tensile strength (Kpa) Compression strength (10% deformation, kPa) Moisture absorption rate (%) Fire rating Example 1 92 104 2.1 A-level Example 2 95 102 1.3 A-level Example 3 91 105 1.6 A-level

[0103] The above experimental results show that the inorganic fiber cotton board prepared in the embodiment 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, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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: treating sepiolite powder with phosphoric acid, loading ammonium polyphosphate, drying and crushing to obtain product A; Step 2: reacting DOPO with γ-aminopropyltriethoxysilane, stirring and dissolving to obtain product B; Step 3: hydrolyze and polycondense methyltrimethoxysilane with diethanolamine, add dibutyltin dilaurate and continue the reaction to obtain product C; Step 4: Prepare a curing solution by combining raw materials including 40-50 parts of sodium silicate, 15-20 parts of potassium silicate, 3-8 parts of polyvinyl alcohol, 10-15 parts of modified attapulgite powder, 5-10 parts of product A, 2-5 parts of nano-silica sol, 0.5-1.2 parts of an organosilicon water repellent, 1-2 parts of product B, 3-5 parts of product C, and 4-6 parts of HBP-NH2; Step 5: Melting and centrifuging the slag into cotton, and wet forming the cotton to obtain a rough inorganic fiber cotton board; Step 6: vacuum dehydrate the inorganic fiber cotton board rough blank obtained in step 5, spray the solidifying liquid prepared in step 4, and then dry it to obtain a fire-resistant inorganic fiber cotton board.

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

3. The preparation method according to claim 1, characterized in that In step 2, DOPO and γ-aminopropyltriethoxysilane are mixed in a mass ratio of (1.2-1.4):1, heated to 120-125°C under nitrogen protection, and stirred for reaction for 4-4.5 hours. After the reaction is completed, the reaction product is dissolved in anhydrous ethanol in 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 3, methyltrimethoxysilane and diethanolamine are mixed in a mass ratio of (3.8-4):1, hydrolyzed and polycondensed at 60-62°C for 3-3.5 hours, and then 0.5%wt dibutyltin dilaurate is added, and the temperature is raised to 80-82°C and the reaction is continued for 1-1.5 hours to obtain product C.

5. The preparation method according to claim 1, characterized in that The curing liquid preparation steps in step 4 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 pre-react for 30-35 minutes; S2, then add nano-silica sol, product B, and product C, raise the temperature to 50-52°C, and stir to react for 1-1.2h; S3, continue to add 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 water repellent, control the temperature at 40-42°C and mature for 2-2.5h; S5. Pass through a 200-mesh sieve, control the temperature at 20-25°C, and adjust the viscosity to 4000-4500 mPa·s using a rheometer to prepare a solidifying liquid.

6. 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.

7. The preparation method according to claim 1, characterized in that In step 5, the fiber diameter of the cotton is 4-6 μm, and the cotton is wet-formed to a thickness of 50 mm to form a rough inorganic fiber cotton board.

8. The preparation method according to claim 1, characterized in that In step 6, vacuum dehydration is performed to a moisture content of 45%-50%. The inorganic fiber cotton board rough 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 seconds.

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

10. A fire-resistant inorganic fiber cotton board, characterized in that: The method is as described in any one of claims 1 to 9.