Composite non-asbestos board and method for producing the same

Abstract

The application belongs to the field of building materials, and discloses a composite non-asbestos board and a preparation method thereof, which are prepared from the following raw materials in parts by weight: 50-70 parts of a composite inorganic base material, 10-20 parts of a natural modified binder, 5-15 parts of a functional regulator, and 8-12 parts of water; the composite inorganic base material is a compound of red mud and talcum powder, and the natural modified binder is a compound of konjac glucomannan and guar gum; the functional regulator comprises nano-silica sol and sodium citrate; the application aims to overcome the shortcomings of the prior art and provide a composite non-asbestos board and a preparation method thereof. The non-asbestos board uses industrial waste such as red mud as the main raw material, and is combined with the natural modified binder and the functional regulator, so that the non-asbestos board has the characteristics of high strength, good toughness, excellent waterproof performance and the like, and the preparation process is simple and stable, and meets the environmental protection requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a composite non-asbestos board and a preparation method thereof. BACKGROUND

[0002] Asbestos boards have been widely used in the field of construction due to their good fireproof, heat-insulating and sound-insulating properties. However, asbestos fibers are highly carcinogenic, and long-term exposure can cause lung cancer, mesothelioma and other serious diseases. Therefore, many countries have banned the production and use of asbestos materials. Therefore, it is an inevitable trend for the industry to develop non-asbestos substitute materials.

[0003] At present, there are mainly the following types of non-asbestos boards on the market: non-asbestos cement boards using cement as the base material, which have high strength but poor toughness, are prone to cracking, and have poor waterproof performance and are prone to deformation in humid environments; non-asbestos gypsum boards using gypsum as the base material, which have good fireproof performance but low strength and poor water resistance, and can only be used in dry environments; and non-asbestos boards using plant fibers as reinforcing materials, which have good environmental friendliness but insufficient aging resistance and are prone to performance degradation over time.

[0004] There are still many problems in the preparation process of existing non-asbestos boards: first, traditional organic binders such as urea-formaldehyde resin and phenol-formaldehyde resin are commonly used, which release harmful gases such as formaldehyde during production and use, have insufficient environmental friendliness, and have high costs; second, some non-asbestos boards use industrial waste such as fly ash and slag as raw materials, but due to imperfect waste pretreatment processes, effective alkali removal and impurity removal are not performed, resulting in large fluctuations in product performance and difficulty in ensuring strength and stability; third, problems such as uneven mixing of slurry, improper control of molding pressure, and unreasonable curing system in the preparation process further affect the comprehensive performance of non-asbestos boards.

[0005] In addition, existing non-asbestos boards also have deficiencies in functionality, such as insufficient antibacterial and mildew-resistant performance, which can easily breed bacteria and mold in humid environments, affecting safety and durability. At the same time, the production efficiency of existing non-asbestos boards is low, the energy consumption is high, and it does not meet the development concept of green manufacturing. Based on the above status, it is urgent to develop a composite non-asbestos board with excellent performance, good environmental friendliness, stable preparation process and multiple functions. SUMMARY

[0006] The present application aims to overcome the shortcomings of the prior art and provide a composite non-asbestos board and a preparation method thereof. The non-asbestos board uses industrial waste such as red mud as the main raw material, and is combined with natural modified binders and functional regulators, has the characteristics of high strength, good toughness, excellent waterproof performance, and has a simple and stable preparation process that meets environmental requirements.

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] The technical scheme provided by the present application is: a composite non-asbestos board is made from the following raw materials by weight: 50-70 parts of a composite inorganic base material, 10-20 parts of a natural modified binder, 5-15 parts of a functional regulator, and 8-12 parts of water;

[0009] The composite inorganic base material is a compound of red mud and talcum powder, wherein the mass ratio of red mud to talcum powder is 3-4:1, the loss on ignition of the red mud after pretreatment is ≤5%, the fineness is ≤10% on a 0.08mm square mesh sieve, the whiteness of the talcum powder is ≥90%, and the particle size is 10-20μm;

[0010] The natural modified binder is a compound of modified konjac glucomannan and guar gum, and the mass ratio of the two is 2-3:1, and the modified konjac glucomannan is modified by cross-linking with epichlorohydrin.

[0011] The functional regulator includes nano-silica sol and sodium citrate, and the mass ratio of nano-silica sol to sodium citrate is 3-4:1.

[0012] Further, the red mud pretreatment method is: mixing red mud and water at a mass ratio of 1:3-5, stirring for 30-60min, and then standing for 2-4h, discarding the supernatant, and repeating the operation until the pH of the leaching solution is ≤9; the filter cake after filtration is dried in a blast drying oven at 105-110℃ for 12-24h, and then ball milled in a ball mill at a speed of 300-400r / min for 2-3h to reach the fineness standard.

[0013] Further, the preparation method of modified konjac glucomannan is: dissolving konjac glucomannan in deionized water to prepare a solution with a mass fraction of 5-8%, adjusting the pH to 8-9 with a 10% sodium hydroxide solution, adding 3-5% of the mass of konjac glucomannan of epichlorohydrin, stirring at a speed of 200-300r / min in a constant temperature water bath at 60-70℃ for 2-3h, adjusting the pH to 7 with a 10% hydrochloric acid after reaction, and then pulverizing to 80-100 mesh after spray drying, wherein the spray drying inlet air temperature is 180-200℃, and the outlet air temperature is 80-90℃.

[0014] Further, the particle size of the nano-silica sol is 20-40nm, the solid content is 25-35wt%, and the pH value is 8-9, and the nano-silica sol is an acidic silica sol neutralized to the pH value range by ammonia water.

[0015] Further, the composite inorganic base material further includes 5-10 parts by weight of mica powder, the diameter-thickness ratio of the mica powder is 50-80:1, and the mica powder is a sheet structure mica powder prepared by wet grinding.

[0016] The present application also provides a preparation method of a composite non-asbestos board, comprising the following steps:

[0017] S1: substrate activation: mix the pretreated red mud with talc powder, add 0.5-1% silane coupling agent KH-570 (previously diluted with ethanol to 10% by mass) based on the mass of the composite inorganic substrate, and stir in a high-speed mixer at a speed of 800-1000 r / min for 15-20 min for surface activation. The material temperature is controlled at 40-50°C during stirring;

[0018] S2: binder preparation: mix the modified konjac glucomannan with guar gum in proportion, add 3-5 times the weight of 50-60°C deionized water, and stir in an electric mixer (speed 300-400 r / min) until completely dissolved. Keep at 50°C for standby;

[0019] S3: slurry preparation: add the activated composite inorganic substrate to a double-blade stirring device, dry mix for 5-10 min (blade speed 200-300 r / min), add the natural modified binder solution and 50% by weight of water, adjust the blade speed to 400-500 r / min and stir for 15-20 min, then add the functional regulator and the remaining water, and continue stirring for 25-35 min until the slurry is uniform. The slurry temperature is controlled at 30-40°C;

[0020] S4: vacuum forming: pour the slurry into a steel mold with air holes (size customized according to product requirements), degas in a vacuum drying oven at a vacuum degree of -0.07 to -0.08 MPa for 1-2 min, then transfer to a flat vulcanizing machine, press at a pressure rate of 1-2 MPa / min to 8-12 MPa, press at a temperature of 45-55°C, and hold for 5-7 min;

[0021] S5: gradient curing: place the formed blank in a constant temperature and humidity curing box, first at 50-60°C, relative humidity 75-80%, for 16-20h, then increase the temperature to 75-85°C at a rate of 2-4°C / h, relative humidity adjusted to 50-60%, continue to cure for 20-28h. In the later stage of curing, turn on the air blowing device in the box (air speed 1-2 m / s), cool to room temperature, and then sand with a sander (sandpaper grit 120-180 grit).

[0022] Further, the stirring paddle of the high-speed mixer in S1 is a Z-shaped paddle, and the paddle clearance with the cylinder is 5-10 mm.

[0023] Further, the paddles of the double-blade stirring device in S3 are installed at an angle of 90°.

[0024] Further, in S5, the blank is turned over every 8h during curing, and high-temperature resistant silicone pads are used to support the blank during turning over.

[0025] The beneficial effects of the technical solution are:

[0026] (1) The application uses red mud and talcum powder as a composite inorganic base material. The red mud is pre-processed to have stable performance, and cooperates with talcum powder to improve the strength and hardness of the board. The addition of mica powder can enhance the toughness and bending resistance of the board, and reduce cracking. The modified natural adhesive is modified by cross-linking with epichlorohydrin, and the bonding performance is significantly improved. The composite of guar gum can further improve the integrity and stability of the board. The nano-silica sol in the functional regulator can fill the internal pores of the board, improve the density and strength, and sodium citrate can adjust the fluidity of the slurry and improve the forming performance. The synergistic effect of the two makes the asbestos-free board have high strength, high toughness, good waterproof performance and durability.

[0027] (2) The application uses industrial waste such as red mud as the main raw material, realizes the resource utilization of industrial waste, reduces solid waste pollution, and reduces production cost. The natural modified adhesive replaces the traditional organic adhesive, avoiding the release of harmful gases such as formaldehyde, and meeting the environmental protection requirements. The energy consumption in the preparation process is low, and there is no emission of toxic and harmful substances, which meets the development concept of green manufacturing.

[0028] (3) The application strictly pre-processes the red mud through water washing, drying, ball milling and other processes to ensure the stability of the raw material. The surface of the inorganic base material is treated by silane coupling agent in the base material activation step to improve the compatibility of the inorganic base material and the organic adhesive. The uniformity of the slurry is ensured by controlling the stirring speed, time and temperature during the slurry preparation process. The vacuum forming and gradient curing process can make the internal structure of the board dense, stable and repeatable, which is suitable for industrial production.

[0029] (4) The application can adjust the raw material ratio and process parameters according to actual needs to prepare asbestos-free boards with different properties. For example, by increasing the amount of nano-silica sol, the strength and wear resistance of the board can be improved, and by adding antibacterial agents, the board can be given antibacterial and mildew-resistant properties, expanding its application range.

[0030] (5) The preparation process of the application is simple, convenient to operate, and the parameters of each step are clear and easy to control, which can improve production efficiency and reduce production cost. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The performance comparison parameter table of a composite asbestos-free board and its preparation method proposed by the application;

[0032] Figure 2 The preparation difference comparison table of a composite asbestos-free board and its preparation method proposed by the application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0034] The implementation process is as follows:

[0035] Embodiment 1

[0036] Please refer to Figures 1-2 The present application provides a technical solution: a composite non-asbestos board is made of the following raw materials by actual mass: 50 kg of composite inorganic base material, 10 kg of natural modified binder, 5 kg of functional regulator, and 8 kg of water.

[0037] The composite inorganic base material is a compound of red mud and talcum powder, and the mass ratio of the red mud to the talcum powder is 3:1. The loss on ignition of the red mud after pretreatment is 4%, and the fineness is 8% of the 0.08 mm square hole sieve. The whiteness of the talcum powder is 91%, and the particle size is 10-15 μm.

[0038] The natural modified binder is a compound of konjac glucomannan and guar gum, and the mass ratio of the two is 2:1. The konjac glucomannan is crosslinked and modified by epoxy chloropropane.

[0039] The crosslinking modification method of the above-mentioned konjac glucomannan by epoxy chloropropane is as follows:

[0040] Konjac glucomannan powder is dissolved in deionized water to prepare a solution with a mass fraction of 5%. The solution is stirred in a 30℃ constant temperature water bath at a speed of 200 r / min until it is completely dissolved. The pH is adjusted to 8.5 with a 10% sodium hydroxide solution. 3% of epoxy chloropropane (previously diluted with anhydrous ethanol to a concentration of 20%) of the mass of konjac glucomannan is slowly added dropwise at a speed of 1 mL / min. The temperature is maintained at 60℃ and the stirring speed is maintained at 300 r / min during the dropwise addition process. After the dropwise addition is completed, the reaction is continued for 2 h. During this period, samples are taken every 15 min for viscosity detection. When the viscosity reaches 3 times the initial value, the reaction is terminated. After the reaction is completed, the pH is adjusted to 7 with a 10% hydrochloric acid solution. The solution is then spray dried (inlet air temperature 180℃, outlet air temperature 85℃) to obtain crosslinked modified konjac glucomannan. The product is pulverized to 80 mesh for use.

[0041] The functional regulator includes nano-silica sol and sodium citrate, and the mass ratio of the two is 3:1. The particle size of the nano-silica sol is 20-25 nm, the solid content is 25 wt%, and the pH value is 8-8.5. The sodium citrate is commercially available analytical pure.

[0042] The composite inorganic base material further comprises 5 kg of mica powder, the diameter-thickness ratio of the mica powder is 50-60:1, and the mica powder is a lamellar structure mica powder prepared by wet grinding;

[0043] The preparation method of the composite asbestos-free board comprises the following steps:

[0044] S1: base material activation: the pretreated red mud is mixed with talcum powder, and 0.5% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) of the mass of the composite inorganic base material is added, and surface activation is carried out in a high-speed mixer at a speed of 800 r / min for 15 min, and the material temperature is controlled at 40-45°C during stirring, and the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the paddle clearance is 5-6 mm;

[0045] S2: preparation of the binder: the modified konjac glucomannan is mixed with guar gum in proportion, 3 times the weight of 50-55°C deionized water is added, and stirring is carried out in an electric stirrer (speed 300 r / min) until complete dissolution, and the temperature is kept at 50°C for standby;

[0046] S3: slurry preparation: the activated composite inorganic base material is added to a double-paddle stirring device, dry mixing is carried out for 5 min (paddle speed 200 r / min), natural modified binder solution and 50% of water by weight are added, the paddle speed is adjusted to 400 r / min, stirring is carried out for 15 min, functional regulators and the remaining water are added, and stirring is continued for 25 min until the slurry is uniform, the slurry temperature is controlled at 30-35°C, and the paddles of the double-paddle stirring device are installed in a staggered manner with an included angle of 90°;

[0047] S4: vacuum forming: the slurry is injected into a steel mold with air holes, degassing is carried out in a vacuum drying box at a vacuum degree of -0.07 MPa for 1 min, then transferred to a flat plate vulcanizing machine, and pressurized to 8 MPa at a pressure increasing rate of 1 MPa / min, the pressing temperature is 45-50°C, and the pressure holding time is 5 min;

[0048] S5: gradient curing: the formed blank is placed in a constant temperature and humidity curing box, first cured at 50-55°C and a relative humidity of 75-78% for 16 h, then raised to 75-80°C at a temperature increasing rate of 2°C / h, and the relative humidity is adjusted to 50-55% for continued curing for 20 h, the air blowing device in the box is turned on (air speed 1 m / s) during the later curing period, the blank is turned over every 8 h during the curing process, high-temperature resistant silicone rubber pads are used for support during turning over, and after cooling to room temperature, sanding is carried out on a sander (sanding paper grit 120 grit) to obtain the product;

[0049] The composite asbestos-free board prepared in the embodiment uses red mud and talcum powder as the composite inorganic base material, realizes the resource utilization of industrial waste, and reduces the production cost; the addition of mica powder improves the toughness and bending strength of the board; the use of natural modified adhesive ensures the bonding performance of the board and has good environmental protection; the addition of the functional regulator further improves the comprehensive performance of the board; and all performance indicators can meet the basic requirements of building materials.

[0050] Embodiment 2:

[0051] Please refer to Figures 1-2 The application provides a technical scheme: a composite asbestos-free board is prepared from the following raw materials by actual mass: 60 kg of a composite inorganic base material, 15 kg of a natural modified adhesive, 10 kg of a functional regulator, and 10 kg of water.

[0052] The composite inorganic base material is a compound of red mud and talcum powder, the mass ratio of the red mud to the talcum powder is 3.5:1, the loss on ignition of the red mud after pretreatment is 3.5%, and the fineness is 7% of a 0.08 mm square hole screen residue; the whiteness of the talcum powder is 92%, and the particle size is 15-20 μm.

[0053] The natural modified adhesive is a compound of konjac glucomannan and guar gum, the mass ratio of the two is 2.5:1, and the konjac glucomannan is crosslinked and modified by epoxy chloropropane;

[0054] The crosslinking modification method of the konjac glucomannan by epoxy chloropropane is the same as that in embodiment 1.

[0055] The functional regulator includes nano-silica sol and sodium citrate, the mass ratio of the two is 3.5:1, the particle size of the nano-silica sol is 25-30 nm, the solid content is 30 wt%, and the pH value is 8.5-9; the sodium citrate is commercially available analytical pure;

[0056] The composite inorganic base material further includes 7 kg of mica powder, the diameter-thickness ratio of the mica powder is 60-70:1, and the mica powder is a sheet structure mica powder prepared by wet grinding;

[0057] The preparation method of the composite asbestos-free board includes the following steps:

[0058] S1: base material activation: the pretreated red mud and talcum powder are mixed, 0.8% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) of the mass of the composite inorganic base material is added, surface activation is performed in a high-speed mixer at a speed of 900 r / min for 18 min, the material temperature is controlled at 45-50 DEG C during the stirring process, the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the paddle clearance is 7-8 mm;

[0059] S2: Adhesive preparation: mix modified konjac glucomannan with guar gum in proportion, add 4 times weight of 55-60℃ deionized water, stir to complete dissolution in an electric mixer (350r / min), and keep at 50℃ for standby;

[0060] S3: Slurry preparation: add activated composite inorganic base material to a double-paddle stirring device, dry mix for 8min (paddle speed 250r / min), add natural modified adhesive solution and 50% weight of water, adjust paddle speed to 450r / min, stir for 18min, then add functional regulator and the remaining water, continue to stir for 30min until the slurry is uniform, the slurry temperature is controlled at 35-40℃, the paddles of the double-paddle stirring device are installed in a staggered manner with an included angle of 90°;

[0061] S4: Vacuum forming: pour the slurry into a steel mold with air holes, degas in a vacuum drying box at a vacuum degree of-0.075MPa for 1.5min, then transfer to a flat plate vulcanizing machine, pressurize to 10MPa at a pressure increasing rate of 1.5MPa / min, the pressing temperature is 50-55℃, and the pressure holding time is 6min;

[0062] S5: Gradient curing: place the formed blank in a constant temperature and humidity curing box, first cure at 55-60℃ and a relative humidity of 78-80% for 18h, then increase the temperature to 80-85℃ at a rate of 3℃ / h and adjust the relative humidity to 55-60%, continue to cure for 24h, open the air blowing device (air speed 1.5m / s) in the box during the later curing period, turn over the blank every 8h during the curing process, use high-temperature resistant silicone rubber pads for support during turning over, and after cooling to room temperature, sand the surface with a sanding machine (sandpaper grit 150) to obtain the product;

[0063] In this embodiment, the ratio of raw materials and the preparation process parameters are adjusted based on Example 1; the amount of composite inorganic base material and functional regulator is increased, which improves the strength and functionality of the board; by optimizing the stirring time, pressing pressure and curing time, the raw materials are more uniformly mixed, the board structure is more dense, and the performance is more stable; the prepared non-asbestos board has better comprehensive performance than Example 1.

[0064] Example 3:

[0065] Please refer to Figures 1-2 The present application provides a technical solution: a composite non-asbestos board is made from the following actual mass of raw materials: composite inorganic base material 65kg, natural modified adhesive 18kg, functional regulator 12kg, and water 11kg.

[0066] The composite inorganic base material is a compound of red mud and talcum powder, the mass ratio of red mud to talcum powder is 3.8:1, the loss on ignition of the red mud after pretreatment is 4.5%, and the fineness is 9% through 0.08 mm square hole screen; the whiteness of the talcum powder is 93%, and the particle size is 18-20 μm;

[0067] The natural modified binder is a compound of konjac glucomannan and guar gum, the mass ratio of the two is 2.8:1, and the konjac glucomannan is modified by cross-linking with epichlorohydrin;

[0068] The above-mentioned method for modifying konjac glucomannan by cross-linking with epichlorohydrin is the same as that in Example 1.

[0069] The functional regulator includes nano-silica sol and sodium citrate, the mass ratio of the two is 3.8:1, the particle size of the nano-silica sol is 35-40 nm, the solid content is 32 wt%, and the pH value is 8.5-9; the sodium citrate is commercially available analytical pure;

[0070] The composite inorganic base material further includes 8 kg of mica powder, the diameter-thickness ratio of the mica powder is 70-80:1, and the mica powder is a sheet structure mica powder prepared by wet grinding;

[0071] The above-mentioned method for preparing the composite non-asbestos board includes the following steps:

[0072] S1: Base material activation: mix the pretreated red mud and talcum powder, add 0.8% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) based on the mass of the composite inorganic base material, and perform surface activation by stirring at a speed of 950 r / min for 18 min in a high-speed mixer, the material temperature is controlled at 45-50°C during stirring, the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the gap between the paddle and the cylinder is 8-9 mm;

[0073] S2: Binder preparation: mix the modified konjac glucomannan and guar gum according to the proportion, add 4.5 times the weight of deionized water at 55-60°C, and stir until completely dissolved in an electric stirrer (speed 380 r / min), and keep at 50°C for standby;

[0074] S3: Slurry preparation: add the activated composite inorganic base material to a double-paddle stirring device, dry mix for 8 min (paddle speed 280 r / min), add the natural modified binder solution and 50% of the water, adjust the paddle speed to 480 r / min and stir for 18 min, then add the functional regulator and the remaining water, and continue stirring for 32 min until the slurry is uniform, the slurry temperature is controlled at 35-40°C, and the paddles of the double-paddle stirring device are installed at an angle of 90°;

[0075] S4: vacuum forming: the slurry is injected into a steel mold with air holes, degassed in a vacuum drying oven at a vacuum degree of-0.08 MPa for 1.8 min, then transferred to a flat plate vulcanizing machine, and pressurized to 11 MPa at a pressure increasing rate of 1.8 MPa / min, the pressing temperature is 50-55℃, and the pressure holding time is 6.5 min;

[0076] S5: gradient curing: the formed blank is placed in a constant temperature and humidity curing box, first cured at 55-60℃ and a relative humidity of 78-80% for 19h, then raised to 80-85℃ at a temperature increasing rate of 3.5℃ / h, and the relative humidity is adjusted to 55-60%, and cured for another 26h, during the later curing period, the air blowing device in the box is turned on (air speed 1.8m / s), and the blank is turned over every 8h during the curing process, and a high-temperature resistant silicone rubber pad is used for support during turning over, and after cooling to room temperature, the blank is sanded by a sander (sandpaper grit 160) to obtain the product;

[0077] The embodiment further improves the use amount of the composite inorganic base material, the natural modified binder and the functional regulator, optimizes the stirring speed and the pressing pressure and the like process parameters; the higher base material use amount ensures the structural stability of the board, the increased binder use amount makes the board more integral, and the reasonable proportioning of the functional regulator further improves the strength and waterproof performance of the board; the prepared non-asbestos board is excellent in the key indicators such as the bending strength, the compressive strength and the water absorption.

[0078] Example 4:

[0079] Please refer to Figures 1-2 The application provides a composite non-asbestos board which is made of the following raw materials in actual mass: 70kg of a composite inorganic base material, 20kg of a natural modified binder, 15kg of a functional regulator and 12kg of water.

[0080] The composite inorganic base material is a compound of red mud and talcum powder, the mass ratio of the red mud to the talcum powder is 4:1, the loss on ignition of the red mud after pretreatment is 5%, and the fineness is 10% of the 0.08mm square hole sieve; the whiteness of the talcum powder is 94%, and the particle size is 15-20μm.

[0081] The natural modified binder is a compound of konjac glucomannan and guar gum, the mass ratio of the two is 3:1, and the konjac glucomannan is modified by crosslinking with epichlorohydrin.

[0082] The method for modifying the above konjac glucomannan by crosslinking with epichlorohydrin is the same as that in Example 1.

[0083] The functional regulator includes nano-silica sol and sodium citrate, the mass ratio of the two is 4:1, the particle size of the nano-silica sol is 30-40nm, the solid content is 35wt%, and the pH value is 8.5-9; the sodium citrate is commercially available analytical pure;

[0084] The composite inorganic base material further comprises 10 kg of mica powder, the diameter-thickness ratio of the mica powder is 75-80:1, and the mica powder is a lamellar structure mica powder prepared by wet grinding;

[0085] The preparation method of the composite non-asbestos board comprises the following steps:

[0086] S1: base material activation: the pretreated red mud is mixed with talcum powder, 1% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) of the mass of the composite inorganic base material is added, and surface activation is carried out in a high-speed mixer at a speed of 1000 r / min for 20 min, the material temperature is controlled at 45-50°C during stirring, the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the gap between the paddle and the cylinder is 9-10 mm;

[0087] S2: preparation of the binder: the modified konjac glucomannan is mixed with guar gum in proportion, 5 times the weight of 55-60°C deionized water is added, and stirring is carried out in an electric stirrer (speed 400 r / min) until complete dissolution, and the mixture is kept at 50°C for standby;

[0088] S3: slurry preparation: the activated composite inorganic base material is added to a double-paddle stirring device, dry mixing is carried out for 10 min (paddle speed 300 r / min), natural modified binder solution and 50% of water by weight are added, the paddle speed is adjusted to 500 r / min, stirring is carried out for 20 min, functional regulators and the remaining water are added, and stirring is continued for 35 min until the slurry is uniform, the slurry temperature is controlled at 35-40°C, and the paddles of the double-paddle stirring device are installed in a staggered manner with an included angle of 90°;

[0089] S4: vacuum forming: the slurry is injected into a steel mold with air vents, degassing is carried out in a vacuum drying box at a vacuum degree of -0.08 MPa for 2 min, then the slurry is transferred to a flat plate vulcanizing machine, the pressure is increased to 12 MPa at a pressure increasing rate of 2 MPa / min, the pressing temperature is 50-55°C, and the pressure holding time is 7 min;

[0090] S5: gradient curing: the formed blank is placed in a constant temperature and humidity curing box, first cured at 55-60°C and a relative humidity of 78-80% for 20 h, then the temperature is increased to 80-85°C at a temperature increasing rate of 4°C / h, the relative humidity is adjusted to 55-60%, and the curing is continued for 28 h, the air blowing device in the box is turned on (air speed 2 m / s) during the later stage of curing, the blank is turned over every 8 h during the curing process, high-temperature resistant silicone rubber pads are used for support during turning over, and after cooling to room temperature, sanding is carried out on the blank by a sander (sandpaper grit 180 grit) to obtain the product;

[0091] The embodiment adopts the highest proportion of raw material ratio and optimized process parameters, the highest amount of composite inorganic base material, ensures the high strength basis of the plate; the largest amount of natural modified binder, further enhances the bonding performance and integrity of the plate; the highest amount of functional regulator, effectively improves the density and waterproof performance of the plate; through high-strength pressing and sufficient curing, the internal structure of the plate is more dense, and the performance reaches the optimum, which can meet the application scene with high requirements for strength and durability.

[0092] Embodiment 5:

[0093] Please refer to Figures 1-2 The application provides a technical scheme: a composite non-asbestos plate is made of the following raw materials by actual mass: 55 kg of composite inorganic base material, 12 kg of natural modified binder, 8 kg of functional regulator, and 9 kg of water.

[0094] The composite inorganic base material is a compound of red mud and talcum powder, the mass ratio of the red mud to the talcum powder is 3.2:1, the loss on ignition of the red mud after pretreatment is 3.8%, and the fineness is 0.08 mm square hole screen residue of 7%; the whiteness of the talcum powder is 91.5%, and the particle size is 12-18 μm;

[0095] The natural modified binder is a compound of konjac glucomannan and guar gum, the mass ratio of the two is 2.2:1, and the konjac glucomannan is cross-linked and modified by epoxy chloropropane;

[0096] The cross-linking modification method of the above-mentioned konjac glucomannan by epoxy chloropropane is the same as that in embodiment 1.

[0097] The functional regulator includes nano-silica sol and sodium citrate, and the mass ratio of the two is 3.2:1, the particle size of the nano-silica sol is 22-30 nm, the solid content is 28 wt%, and the pH value is 8-8.5; the sodium citrate is commercially available analytical pure;

[0098] The composite inorganic base material further includes 6 kg of mica powder, the diameter-thickness ratio of the mica powder is 55-65:1, and the mica powder is a lamellar structure mica powder prepared by wet grinding;

[0099] The preparation method of the above-mentioned composite non-asbestos plate includes the following steps:

[0100] S1: base material activation: the pretreated red mud and talcum powder are mixed, 0.6% of silane coupling agent KH-570 (previously diluted with ethanol to 10% by mass) of the composite inorganic base material is added, surface activation is carried out in a high-speed mixer at a speed of 850 r / min for 16 min, the material temperature is controlled at 42-47 DEG C during stirring, the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the paddle clearance is 6-7 mm;

[0101] S2: Adhesive preparation: Mix modified konjac glucomannan with guar gum in proportion, add 3.5 times weight of 52-57℃ deionized water, stir to complete dissolution in an electric mixer (speed 320r / min), and keep at 50℃ for standby;

[0102] S3: Slurry preparation: Add activated composite inorganic base material to a double-paddle stirring device, dry mix for 6min (paddle speed 220r / min), add natural modified adhesive solution and 50% weight of water, adjust the paddle speed to 420r / min and stir for 16min, then add functional regulator and the remaining water, continue to stir for 28min until the slurry is uniform, the slurry temperature is controlled at 32-37℃, and the paddles of the double-paddle stirring device are installed at an angle of 90°;

[0103] S4: Vacuum forming: Pour the slurry into a steel mold with air holes, degas in a vacuum drying box at a vacuum degree of-0.072MPa for 1.2min, then transfer to a flat plate vulcanizing machine, press at a pressure increasing rate of 1.2MPa / min to 9MPa, press at a temperature of 46-52℃, and keep the pressure for 5.5min;

[0104] S5: Gradient curing: Place the formed blank in a constant temperature and humidity curing box, first cure at 52-57℃ and 76-79% relative humidity for 17h, then increase the temperature to 76-82℃ at a rate of 2.5℃ / h and adjust the relative humidity to 52-57%, continue to cure for 22h, open the air blowing device (air speed 1.2m / s) in the box during the later curing period, turn the blank over every 8h during the curing process, use high-temperature resistant silicone pads for support during turning, and sand the blank after cooling to room temperature (sandpaper grit 130) to obtain the product;

[0105] This example uses a moderate to low raw material ratio and a relatively mild process parameter setting; by reasonably controlling the ratio of red mud and talcum powder, the amount of adhesive, and the ratio of functional regulator, the production cost is reduced while the basic performance of the board is ensured; the optimization of slurry preparation and forming process parameters makes the raw materials mix evenly, the board structure stable, and suitable for general building scene applications which are more sensitive to cost.

[0106] Example 6:

[0107] Please refer to Figures 1-2 The present application provides a technical solution: a composite asbestos-free board made from the following actual mass of raw materials: composite inorganic base material 62kg, natural modified adhesive 16kg, functional regulator 10kg, water 10.5kg;

[0108] The composite inorganic base material is a compound of red mud and talc powder, the mass ratio of red mud to talc powder is 3.6:1, the loss on ignition of the red mud after pretreatment is 4.2%, and the fineness is 8.5% of 0.08mm square hole screen residue; the whiteness of the talc powder is 92.5%, and the particle size is 14-20μm;

[0109] The natural modified binder is a compound of konjac glucomannan and guar gum, the mass ratio of the two is 2.6:1, and the konjac glucomannan is modified by crosslinking with epichlorohydrin;

[0110] The above-mentioned method for crosslinking modification of konjac glucomannan with epichlorohydrin is the same as that in Example 1.

[0111] The functional regulator includes nano-silica sol and sodium citrate, the mass ratio of the two is 3.6:1, the particle size of the nano-silica sol is 28-35nm, the solid content is 31wt%, and the pH value is 8.2-8.8; the sodium citrate is commercially available analytical pure;

[0112] The composite inorganic base material also includes 9kg of mica powder, the diameter-thickness ratio of the mica powder is 65-75:1, and the mica powder is a lamellar structure mica powder prepared by wet grinding;

[0113] The above-mentioned method for preparing the composite non-asbestos board includes the following steps:

[0114] S1: base material activation: mix the pretreated red mud and talc powder, add 0.9% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) based on the mass of the composite inorganic base material, and stir in a high-speed mixer at a speed of 950r / min for 19min for surface activation, the material temperature is controlled at 44-48℃ during stirring, the stirring paddle of the high-speed mixer is a Z-shaped paddle, and the paddle clearance from the cylinder is 8-9mm;

[0115] S2: binder preparation: mix the modified konjac glucomannan and guar gum according to the proportion, add 4.2 times the weight of 54-58℃ deionized water, and stir in an electric stirrer (speed 360r / min) until completely dissolved, and keep at 50℃ for standby;

[0116] S3: slurry preparation: add the activated composite inorganic base material to a double-paddle stirring device, dry mix for 9min (paddle speed 270r / min), add the natural modified binder solution and 50% of the water, adjust the paddle speed to 460r / min and stir for 17min, then add the functional regulator and the remaining water, and continue to stir for 32min until the slurry is uniform, the slurry temperature is controlled at 34-38℃, and the paddles of the double-paddle stirring device are installed at an angle of 90°;

[0117] S4: vacuum forming: the slurry was injected into a steel mold with air vents, degassed in a vacuum drying oven at a vacuum degree of-0.078 MPa for 1.7 min, then transferred to a flat plate vulcanizing machine, and pressurized to 10.5 MPa at a pressure increasing rate of 1.7 MPa / min, the pressing temperature was 48-53℃, and the pressure holding time was 6.2 min;

[0118] S5: gradient curing: the formed blank was placed in a constant temperature and humidity curing box, first cured at 53-58℃ and a relative humidity of 77-79% for 18.5h, then raised to 78-83℃ at a temperature increasing rate of 3.2℃ / h, and the relative humidity was adjusted to 54-58% for further curing for 25h, during the later stage of curing, the air blowing device in the box was turned on (air speed 1.6m / s), and the blank was turned over every 8h during the curing process, and high-temperature resistant silicone rubber pads were used for support during turning over, and after cooling to room temperature, sanding was performed on the blank using a sander (sandpaper grit 160) to obtain the product;

[0119] In this embodiment, the raw material ratio is moderately high, and the process parameters are set accurately; by optimizing the red mud pretreatment process and substrate activation parameters, the activity and compatibility of the inorganic substrate are improved; the reasonable ratio of the binder and the functional regulator balances the strength, toughness and waterproof performance of the board; the precise control of the gradient curing process further reduces the internal stress of the board and reduces the risk of cracking, which is suitable for building scenarios with high comprehensive performance requirements.

[0120] Comparative Example 1

[0121] For reference Figures 1-2 The present application provides a kind of comparative technical scheme: a kind of non-asbestos board is made of the following actual mass of raw materials: composite inorganic substrate 60kg (only red mud is used, no talc powder is added), natural modified binder 15kg, functional regulator 10kg, water 10kg;

[0122] The loss on ignition of the red mud after pretreatment is 3.5%, and the fineness is 7% on a 0.08mm square mesh sieve; the types and parameters of the natural modified binder and the functional regulator are the same as in Example 2; the composite inorganic substrate also includes 7kg of mica powder;

[0123] The preparation method is the same as in Example 2 except that no talc powder is added to the substrate;

[0124] This comparative example does not add talc powder, and only uses red mud as the inorganic substrate; compared with Example 2, the strength and toughness of the board are significantly reduced, the bending strength is reduced by about 20%, the compressive strength is reduced by about 15%, and the surface flatness is poor; the reason is that the absence of talc powder leads to an unreasonable particle size distribution of the substrate, which cannot form a dense structure, and the absence of the lubricating effect of talc powder reduces the flowability of the slurry, affecting the forming effect.

[0125] Comparative Example 2

[0126] For reference Figures 1-2 , the present application provides a kind of contrast technical solutions: a kind of asbestosis board is made of following actual mass of raw materials: 60kg of composite inorganic base material, binder 15kg (using unmodified konjac glucomannan, without adding guar gum), functional regulator 10kg, water 10kg;

[0127] The type and parameter of composite inorganic base material are same with example 2;The type and parameter of functional regulator are same with example 2;Composite inorganic base material also includes 7kg of mica powder;

[0128] Preparation method is except that binder is unmodified konjac glucomannan, and the remaining steps and parameters are same with example 2;

[0129] This example uses unmodified konjac glucomannan as binder, and does not add guar gum;Compared with example 2, the bonding performance of board material decreases significantly, and the bending strength decreases by about 25%, and the board material is prone to delamination phenomenon;Reason is that unmodified konjac glucomannan has insufficient bonding force, and lacks the synergistic thickening effect of guar gum, which leads to poor slurry stability and poor integrity of board material.

[0130] Comparative example 3

[0131] For reference Figures 1-2 , the present application provides a kind of contrast technical solutions: a kind of asbestosis board is made of following actual mass of raw materials: 60kg of composite inorganic base material, natural modified binder 15kg, functional regulator 10kg (only add nano-silica sol, without adding sodium citrate), water 10kg;

[0132] The type and parameter of composite inorganic base material are same with example 2;The type and parameter of natural modified binder are same with example 2;Composite inorganic base material also includes 7kg of mica powder;

[0133] Preparation method is except that functional regulator does not add sodium citrate, and the remaining steps and parameters are same with example 2;

[0134] This example does not add sodium citrate, and only uses nano-silica sol as functional regulator;Compared with example 2, the slurry fluidity decreases significantly, and the agglomeration phenomenon is prone to appear in stirring process, the porosity of board material after forming increases by about 10%, and the water absorption increases by about 15%;Reason is that the absence of sodium citrate leads to the inability to effectively regulate slurry pH value and dispersibility, nano-silica sol is easy to agglomerate, and cannot fully play the filling role, which affects the density and waterproof performance of board material.

[0135] For reference Figures 1-2 :

[0136] Through the system comparison and analysis of six embodiments and three comparative examples, it can be clearly found that the composite non-asbestos board technical scheme proposed in the application overcomes many defects existing in the prior art in raw material synergistic design, process parameter optimization and performance improvement.

[0137] From the synergistic effect of the raw material system, the application forms a multi-phase synergistically enhanced material system by scientifically compounding the composite inorganic base material, the naturally modified binder and the functional regulator, which is a substantial difference from the prior art; in the embodiments 1-6, the red mud and talcum powder are compounded as the inorganic base material at a mass ratio of 3-4:1, wherein the red mud is strictly pretreated (washed with water to remove alkali to pH≤9, ball milled to 0.08mm square hole screen residue≤10%), which effectively solves the problems of high impurity and low activity of the red mud; the introduction of talcum powder fills the gap between the red mud particles through particle grading optimization, and at the same time, the layered structure of talcum powder improves the fluidity of the slurry; comparative example 1 does not add talcum powder, but only uses red mud as the inorganic base material, which reduces the bending strength of the board by about 20% and the compressive strength by about 15%, and the surface flatness is poor, which fully proves the necessity of compounding red mud and talcum powder; in the binder system, the modified konjac glucomannan crosslinked with epoxy chloropropane is compounded with guar gum at a ratio of 2-3:1, the modified konjac glucomannan forms a three-dimensional network structure through crosslinking reaction, and the synergistic effect with guar gum significantly improves the bonding strength and water resistance; comparative example 2 uses unmodified konjac glucomannan and does not add guar gum, the board shows obvious delamination, the bending strength decreases by about 25%, which highlights the creative value of the binder modification and compounding technology; the 3-4:1 ratio design of nano-silica sol and sodium citrate in the functional regulator also reflects the synergistic advantage, the nano-silica fills the pores to improve the density, and the sodium citrate adjusts the slurry pH value to optimize the dispersibility, and comparative example 3 lacks sodium citrate, which leads to serious slurry agglomeration, and the water absorption rate increases by about 15%, which further verifies the effectiveness of this synergistic mechanism;

[0138] The preparation process of the present application solves the technical problems of uneven mixing of slurry, loose structure and large performance fluctuation in the prior art through the synergistic optimization of core processes such as substrate activation, gradient pressing and precise curing. In the substrate activation step, the silane coupling agent KH-570 is used to modify the surface of the inorganic substrate (the amount is 0.5-1% of the mass of the substrate), and the coupling agent molecules form chemical bonds with the hydroxyl groups on the surface of the red mud and talcum powder in a high-speed mixer at 800-1000 r / min for 15-20 min, which significantly improves the interfacial compatibility of the inorganic and organic phases. Compared with the direct mixing method in the traditional process, this technology improves the interfacial bonding strength of the board by about 30%, effectively reducing the risk of delamination; In the vacuum forming stage, -0.07 to -0.08 MPa vacuum degassing combined with 1-2 MPa / min gradient pressure pressing (final pressure 8-12 MPa) is used to effectively remove the bubbles in the slurry, which increases the density of the board by 15-20%, and the porosity of the board in the comparative example without vacuum degassing process increases significantly; The gradient curing process is a major innovation of the present application, which first cures at 50-60℃ and 75-80% relative humidity for 16-20h to promote the preliminary crosslinking of the binder, and then increases the temperature to 75-85℃ at a rate of 2-4℃ / h and adjusts the humidity to 50-60% to continue curing for 20-28h. By precisely controlling the temperature and humidity gradient, the stress concentration in the board is reduced, and the cracking rate is reduced to below 5%; Compared with the single curing system in the prior art, this process design improves the dimensional stability of the board by more than 25%, fully embodying the significant progress brought by process optimization;

[0139] From the system comparison of performance data, the composite asbestos-free board of the present application comprehensively surpasses the comparative examples and the prior art in key performance indicators; in terms of mechanical properties, the flexural strength of Example 4 (with the highest raw material ratio) reaches 18.5 MPa, and the compressive strength reaches 65 MPa, which is increased by 35% and 40% respectively compared with Comparative Example 1 (without talc), and increased by 42% and 45% respectively compared with Comparative Example 2 (without modified binder); even for Example 1 with the lowest ratio, the flexural strength and compressive strength reach 12.8 MPa and 48 MPa respectively, which meets the requirements of high-grade in GB / T23451-2009 “Lightweight Partition Board for Building”; in terms of durability, the water absorption rate of Example 2 is only 8.5%, which is reduced by 40% compared with Comparative Example 3 (without sodium citrate), and the strength loss rate is less than 10% after 200 freeze-thaw cycles, which is much lower than the loss rate of 15-20% of the existing asbestos-free board; in terms of environmental performance, the present application uses industrial waste such as red mud (accounting for 75-80% of the inorganic base material) to realize the resource utilization of solid waste, and in terms of production efficiency, the curing period of the present application is shortened by 20-30% compared with the traditional process, and the energy consumption is reduced by about 15%, which meets the green manufacturing concept; these performance advantages not only prove the creativity of the technical solution, but also highlight its application value and promotion prospect in the field of building materials, and provide a new technical path for the development of asbestos-free replacement materials.

[0140] The test method is as follows:

[0141] Flexural strength test: tested according to GB / T7019-2014 “Test Methods for Fiber Cement Products”; samples with a size of 250mm×50mm×10mm were cut from the asbestos-free boards prepared in the examples and comparative examples, and at least 5 samples were prepared for each test; the samples were cured in an environment with a temperature of (23±2)℃ and a relative humidity of (50±5)% for 24h before the test; a three-point bending test device was used, the span was set to 200mm, and the loading rate was (5±1)mm / min, and the maximum load at the time of sample fracture was recorded; 1.2 Compressive strength test;

[0142] Compressive strength test: tested according to GB / T17671-2021 “Cement and Concrete Mortar Strength Test Methods (ISO Method)”; the sample size was 40mm×40mm×40mm, and 6 samples were prepared for each group, which were cured in an environment with a temperature of (23±2)℃ and a relative humidity of (50±5)% for 24h, and then loaded with a cement mortar compressive strength testing machine, the loading rate was controlled at (2400±200)N / s, and the maximum pressure at the time of sample failure was recorded.

[0143] Interface bonding strength test: the interface bonding strength was determined by a splitting test method; a layered sample (simulating the interface between the inorganic phase and the organic phase inside the board) with a size of 100 mm x 100 mm x 20 mm was prepared, a vertical pressure was applied in the center of the sample along the interface direction, the loading rate was (2 ± 0.5) mm / min, and the maximum load at the interface separation was recorded;

[0144] Water absorption test: the test was carried out according to GB / T 17657-2022 "Test methods of physical and chemical properties of wood-based panels and veneered wood-based panels"; the sample size was (50 ± 1) mm x (50 ± 1) mm x original thickness, and at least 5 samples were used in each group; before the test, the sample was dried to constant weight in a (103 ± 2) ℃ air drying oven (the interval between two weighings was 2 h, and the mass difference was not more than 0.02 g), and then was cooled to room temperature in a desiccator, and the dry mass m1 was weighed (accurate to 0.01 g); the sample was completely immersed in (23 ± 2) ℃ distilled water, and the water surface should be at least 20 mm higher than the sample, and after soaking (24 ± 1) h, the sample was taken out, and the surface water was wiped off with a wrung wet towel, and then the mass m2 after water absorption was immediately weighed (accurate to 0.01 g); the water absorption was calculated according to the formula W = (m2-m1) / m1 x 100%, and the arithmetic mean of 5 samples was taken as the test result, and the result was rounded to one decimal place;

[0145] Freeze-thaw cycle test: the test was carried out according to the fast freezing method in GB / T 50082-2009 "Standard for testing methods of long-term performance and durability of ordinary concrete"; the sample size was 100 mm x 100 mm x 100 mm, and 3 samples were used in each group; after the sample was soaked in (23 ± 2) ℃ water for 4 d, it was placed in a freeze-thaw test box, frozen at -18 ℃ for 4 h, and then thawed in 20 ℃ water for 4 h, which was one cycle; a total of 200 cycles were carried out, and the mass loss rate and strength loss rate of the sample were determined after every 50 cycles; the mass loss rate was calculated according to the formula Δm = (m0-mn) / m0 x 100%, wherein m0 was the initial mass, and mn was the mass after n cycles; the strength loss rate was calculated according to the formula Δσ = (σ0-σn) / σ0 x 100%, wherein σ0 was the initial strength, and σn was the strength after n cycles;

[0146] Water resistance test: the sample with a size of 100 mm x 100 mm x 10 mm was soaked in (23 ± 2) ℃ distilled water for 7 d, and then the bending strength retention rate was measured.

[0147] The above-mentioned are only embodiments of the present application, and common technical solutions or common knowledge in the scheme are not described in detail. It should be pointed out that, for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be regarded as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope claimed in the present application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A composite asbestos-free board, characterized in that, It is made from the following raw materials by weight: 50-70 parts of a composite inorganic base material, 10-20 parts of a natural modified binder, 5-15 parts of a functional regulator, and 8-12 parts of water; The composite inorganic base material is a complex of red mud and talcum powder, wherein the mass ratio of red mud to talcum powder is 3-4:1, the loss on ignition of the red mud after pretreatment is ≤5%, the fineness is ≤10% on a 0.08 mm square mesh sieve, the whiteness of the talcum powder is ≥90%, and the particle size is 10-20 μm; The natural modified binder is a complex of modified konjac glucomannan and guar gum, and the mass ratio of the two is 2-3:1, wherein the modified konjac glucomannan is modified by cross-linking of epichlorohydrin; The functional regulator includes nano-silica sol and sodium citrate, and the mass ratio of nano-silica sol to sodium citrate is 3-4:1; The red mud pretreatment method is as follows: red mud and water are mixed at a mass ratio of 1:3-5, stirred for 30-60 min, and then statically deposited for 2-4 h, the supernatant is discarded, and the operation is repeated until the pH of the leaching solution is ≤9; the filter cake is dried in a 105-110°C air-drying oven for 12-24 h, and then ball-milled in a ball mill at a speed of 300-400 r / min for 2-3 h to achieve the required fineness.

2. The composite non-asbestos plate according to claim 1, wherein The preparation method of the modified konjac glucomannan is as follows: konjac glucomannan is dissolved in deionized water to prepare a solution with a mass fraction of 5-8%, the pH is adjusted to 8-9 with a 10% sodium hydroxide solution, 3-5% of epichlorohydrin based on the mass of the konjac glucomannan is added, and the mixture is stirred at a speed of 200-300 r / min in a constant-temperature water bath at 60-70°C for 2-3 h; after the reaction, the pH is adjusted to 7 with a 10% hydrochloric acid solution, and the product is obtained after spray drying and pulverization to 80-100 mesh, wherein the spray drying is carried out at an inlet air temperature of 180-200°C and an outlet air temperature of 80-90°C.

3. The composite non-asbestos plate according to claim 1, wherein The nano-silica sol has a particle size of 20-40 nm, a solid content of 25-35 wt%, and a pH value of 8-9, and is an acidic silica sol neutralized to the pH value range with ammonia water.

4. The composite non-asbestos plate according to claim 1, wherein The composite inorganic base material further includes 5-10 parts by weight of mica powder, the mica powder has a diameter-thickness ratio of 50-80:1, and is a sheet structure mica powder prepared by wet grinding.

5. A method of producing a composite non-asbestos sheet according to any one of claims 1 to 4, characterized by, The method includes the following steps: S1: base material activation: the pretreated red mud and talcum powder are mixed, 0.5-1% of silane coupling agent KH-570 (previously diluted with ethanol to a mass fraction of 10%) based on the mass of the composite inorganic base material is added, and surface activation is performed by stirring at a speed of 800-1000 r / min in a high-speed mixer for 15-20 min, and the material temperature is controlled at 40-50°C during stirring; S2: binder preparation: the modified konjac glucomannan and guar gum are mixed in proportion, 3-5 times the weight of 50-60°C deionized water is added, and stirring is performed at a speed of 300-400 r / min in an electric stirrer until complete dissolution, and the mixture is kept at 50°C for standby use; S3: slurry preparation: after the activation of the composite inorganic substrate into the double paddle stirring equipment, dry mixing 5-10 min, the paddle speed 200-300 r / min, add natural modified binder solution and 50% by weight of water, adjust the paddle speed to 400-500 r / min stirring 15-20 min, then add function regulator and the rest of the water, continue to stir 25-35 min to the slurry uniform, slurry temperature control for 30-40℃; S4: vacuum forming: the slurry into the steel mold with air holes, in the vacuum drying oven with vacuum degree-0.07 to-0.08 MPa conditions degassing 1-2 min, then transferred to the flat plate curing machine, with 1-2 MPa / min pressure rate to 8-12 MPa, pressure temperature 45-55℃, pressure holding time 5-7 min; S5: gradient curing: the forming body is placed in the constant temperature and humidity curing box, first in 50-60℃, relative humidity 75-80% conditions curing 16-20h, then with 2-4℃ / h heating rate to 75-85℃, relative humidity adjusted to 50-60% continue to cure 20-28h, the curing period open the box air blowing device, air blowing device wind speed 1-2 m / s, cooling to room temperature after sanding machine sanding, sandpaper mesh 120-180 mesh.

6. The production method according to claim 5, wherein The stirring paddle of the high-speed mixer in S1 is Z-shaped paddle, the gap between the paddle and the cylinder is 5-10 mm.

7. The preparation method according to claim 5, characterized in that, The paddle of the double paddle stirring equipment in S3 is installed in a staggered manner, with an included angle of 90°.

8. The preparation method according to claim 5, characterized in that, In the curing process in S5, the blank is turned over every 8h, and high-temperature resistant silicone rubber pad is used to support when turning over.

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