A preparation method of a lightweight composite kaolin

Abstract

The present invention discloses a preparation method of lightweight composite kaolin, relating to the field of ceramics. When preparing the lightweight composite kaolin, dopamine is polymerized on the surface of silicon carbide whiskers to obtain modified silicon carbide whiskers; after reacting 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane and methyldiethoxysilane, 2-acryloyl-1-boronic acid is grafted to obtain modified silicone resin; montmorillonite, polyethylene glycol, styrene, 4-vinyl aniline and divinylbenzene are mixed evenly to obtain modified montmorillonite; the modified montmorillonite, modified silicone resin and composite ceramic powder are mixed evenly and then sintered at a gradient temperature to obtain the lightweight composite kaolin. The lightweight composite kaolin prepared by the present invention has excellent plasticity, heat preservation property and crack resistance.

Description

Technical Field

[0001] The present invention relates to the field of ceramics, and specifically to a preparation method of lightweight composite clay. Background Art

[0002] In recent years, with the continuous upsurge of the reform of new wall materials, people have a strong awareness of building energy conservation and insulation, and the requirements for human settlement experience are also getting higher and higher. The development of new energy-saving wall materials with the advantages of lightweight and high strength, heat insulation, fire resistance and earthquake resistance has received great favor. Ceramics have broad prospects in the innovation of new wall materials and the development of new building energy-saving materials. It is expected to replace cement and stones as lightweight and coarse aggregates for precast concrete cast-in-place aggregates such as building reinforced concrete shear walls, beams, columns, and floors. This can not only reduce the self-weight of the building but also improve the building's indoor space insulation, heat insulation, sound absorption, and noise reduction capabilities. Therefore, the present invention prepares a lightweight composite clay with excellent heat preservation performance. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of lightweight composite clay to solve the problems existing in the prior art.

[0004] To solve the above technical problems, the present invention provides the following technical solutions:

[0005] A preparation method of lightweight composite clay includes the following preparation steps:

[0006] (1) Mix silicon carbide whiskers and a 0.02 - 0.03 mol / L aqueous solution of tris(hydroxymethyl)aminomethane in a mass ratio of 1:(1500 - 2500), ultrasonically disperse for 20 - 30 min, add 1 - 3 g / L of dopamine hydrochloride, stir at 20 - 30 °C and 200 - 300 rpm for 15 - 17 h, then filter, wash with deionized water 3 - 5 times, and dry at 60 - 70 °C for 8 - 10 h to obtain modified silicon carbide whiskers;

[0007] (2) Mix 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran evenly, stir at 25 - 35 °C and 200 - 300 rpm for 20 - 30 min, add a hydrochloric acid solution 5 - 6 times the mass of 3-glycidylpropyl(dimethoxy)methylsilane evenly within 6 - 8 min, continue stirring for 23 - 25 h, raise the temperature to 50 - 60 °C and continue stirring for 23 - 25 h, perform rotary evaporation for 1 - 2 h, add ethyl acetate for extraction, wash with saturated sodium hydroxide solution 3 - 5 times, dry with anhydrous calcium chloride for 23 - 25 h to obtain silicone resin; Mix the silicone resin, 2-propen-1-boronic acid, chloroplatinic acid and toluene in a mass ratio of 1:(1 - 2):(0.01 - 0.03):(4 - 6) evenly, stir at 65 - 75 °C and 100 - 200 rpm in a nitrogen atmosphere for 10 - 20 min, raise the temperature to 105 - 115 °C and continue stirring for 11 - 13 h, perform rotary evaporation at 65 - 75 °C for 1 - 2 h, and cool naturally to room temperature to obtain modified silicone resin;

[0008] (3) Mix montmorillonite, polyethylene glycol and deionized water in a mass ratio of 1:(0.06 - 0.07):(60 - 70) evenly, perform ultrasonic dispersion at 20 - 30 °C for 5 - 15 min, raise the temperature to 80 - 90 °C, add styrene 2.2 - 2.4 times the mass of montmorillonite, 4-vinylaniline 0.5 - 1.5 times the mass of montmorillonite, benzoyl peroxide 0.06 - 0.07 times the mass of montmorillonite and divinylbenzene 0.3 - 0.5 times the mass of montmorillonite, stir for 1 - 2 h, raise the temperature to 90 - 100 °C and continue stirring for 0.9 - 1.1 h, cool naturally to room temperature and then filter, wash with deionized water 3 - 5 times, dry at 55 - 65 °C for 23 - 25 h to obtain modified montmorillonite;

[0009] (4) Mix the modified montmorillonite, modified silicone resin and ethanol solution in a mass ratio of 1:(0.1 - 0.2):(0.2 - 0.3) evenly, perform ultrasonic dispersion for 1 - 2 h, add modified silicon carbide whiskers 0.05 - 0.06 times the mass of modified montmorillonite, stir at 900 - 1100 rpm for 11 - 13 h, add composite ceramic powder 0.1 - 0.2 times the mass of modified montmorillonite, use a disk granulator to stir and granulate at 45 - 55 r / min, dry at 80 - 90 °C for 11 - 13 h to obtain a green body; Gradually raise the temperature of the green body and then cool naturally to room temperature to obtain lightweight composite porcelain clay.

[0010] As an optimization, the silicon carbide whiskers described in step (1) are from Qinghe County Chaotai Metal Materials Co., Ltd.

[0011] As an optimization, the reaction equation of the modified silicon carbide whiskers described in step (1) is:

[0012]

[0013] As an optimization, the mixing of 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran described in step (2) is carried out by mixing them in a mass ratio of 1:2:0.7:0.8:19.

[0014] As an optimization, the pH of the hydrochloric acid solution described in step (2) is 1.

[0015] As an optimization, the reaction equation of the silicone resin described in step (2) is:

[0016]

[0017] As an optimization, the reaction equation of the modified silicone resin described in step (2) is:

[0018]

[0019] As an optimization, the polyethylene glycol model in step (3) is PEG-400E, which is from Shanghai Dikai Industry Co., Ltd.

[0020] As an optimization, the volume fraction of the ethanol solution described in step (4) is 50%.

[0021] As an optimization, the composite ceramic powder described in step (4) is obtained by mixing potassium feldspar powder and white gangue powder in a mass ratio of 1:0.3 and ball-milling with corundum balls for 4 h on a planetary ball mill.

[0022] As an optimization, the gradient heating in step (4) is to heat up to 400 °C at a rate of 5 °C / min for preheating for 60 min, then heat up to 1000 °C at a rate of 4 °C / min, keep the temperature for 2 h, and then heat up to 1450 °C at a rate of 2 °C / min and keep the temperature for 4 h.

[0023] As an optimization, the composite ceramic powder described in step (4) is obtained by mixing potassium feldspar powder and white gangue powder.

[0024] As an optimization, the potassium feldspar powder model is 325 mesh, which is from Lingshou Shuangshi Mineral Products Processing Factory.

[0025] As an optimization, the white gangue powder model is 325 mesh, which is from Lingshou Zhanxing Mineral Products Co., Ltd.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0027] When preparing lightweight composite kaolin in the present invention, dopamine is polymerized on the surface of silicon carbide whiskers to obtain modified silicon carbide whiskers; after reacting 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane and methyldiethoxysilane, 2-acryloyl-1-boronic acid is grafted to obtain modified silicone resin; montmorillonite, polyethylene glycol, styrene, 4-vinylaniline and divinylbenzene are mixed evenly to obtain modified montmorillonite; the modified montmorillonite, modified silicone resin and composite ceramic powder are mixed evenly and then sintered by gradient heating to obtain lightweight composite kaolin.

[0028] First, dopamine is polymerized on the surface of silicon carbide whiskers to obtain modified silicon carbide whiskers; after reacting 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane and methyldiethoxysilane, 2-acryloyl-1-boronic acid is grafted to obtain modified silicone resin; a layer of polydopamine is formed on the surface of silicon carbide whiskers. The phenolic hydroxyl group can not only form reversible cross-linking with boric acid, but also form covalent cross-linking with amino groups and coordination binding with metals, improving the plasticity of lightweight composite kaolin; during the sintering process, the carbonization of polydopamine can also generate pores, improving the heat preservation of lightweight composite kaolin; 2-acryloyl-1-boronic acid is grafted by hydrosilylation addition, introducing a boric acid structure. At low temperature, a reversible borate cross-linking network is formed, and at high temperature calcination, a carbothermal reduction reaction occurs with free carbon, filling and supporting the pore structure, improving the plasticity and crack resistance of lightweight composite kaolin.

[0029] Second, montmorillonite, polyethylene glycol, styrene, 4-vinylaniline and divinylbenzene are mixed evenly to obtain modified montmorillonite; the modified montmorillonite, modified silicone resin and composite ceramic powder are mixed evenly and then sintered by gradient heating to obtain lightweight composite kaolin; polyethylene glycol and styrene are used to cooperate in pore formation during high temperature calcination, improving the heat preservation of lightweight composite kaolin; at the same time, 4-vinylaniline participating in surface polymerization introduces an amino group, which reacts with the epoxy group in the silicone resin at low temperature to form a chemical bond and a hydroxyl structure that can be removed at high temperature, further improving the plasticity and heat preservation of lightweight composite kaolin; the modified silicone resin can reduce the thermal conductivity of the ceramic, form pores during high temperature sintering, reduce the ceramic density, and improve the heat preservation of lightweight composite kaolin; gradient heating calcination is used to ensure that the organic matter is fully oxidized to form pores at 400 °C, the montmorillonite undergoes a phase change at 1000 °C, changes the microstructure, inhibits the propagation and expansion of cracks, and boron undergoes a carbothermal reduction reaction with free carbon at 1400 °C, improving the heat preservation and crack resistance of lightweight composite kaolin. Specific embodiments

[0030] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Embodiment 1:

[0032] A preparation method of lightweight composite kaolin, the preparation method of the lightweight composite kaolin includes the following preparation steps:

[0033] (1) Mix silicon carbide whiskers and 0.02 mol / L tris(hydroxymethyl)aminomethane aqueous solution according to a mass ratio of 1:1500, ultrasonically disperse for 20 min, add 1 g / L hydrochloric acid dopamine, stir at 20 °C and 200 rpm for 17 h, then filter, wash 3 times with deionized water, and dry at 60 °C for 10 h to obtain modified silicon carbide whiskers;

[0034] (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran, stir at 25 °C and 200 rpm for 30 min, uniformly add a hydrochloric acid solution 5 times the mass of 3-glycidoxypropyl(dimethoxy)methylsilane within 6 min, continue to stir for 25 h, raise the temperature to 50 °C and continue to stir for 25 h, rotary evaporate for 1 h, add ethyl acetate for extraction, wash 3 times with saturated sodium hydroxide solution, and dry with anhydrous calcium chloride for 23 h to obtain a silicone resin; Mix the silicone resin, 2-propene-1-boronic acid, chloroplatinic acid and toluene according to a mass ratio of 1:1:0.01:4, stir at 65 °C and 100 rpm in a nitrogen atmosphere for 20 min, raise the temperature to 105 °C and continue to stir for 13 h, rotary evaporate at 65 °C for 2 h, and naturally cool to room temperature to obtain a modified silicone resin;

[0035] (3) Mix montmorillonite, polyethylene glycol and deionized water according to a mass ratio of 1:0.06:60, ultrasonically disperse at 20 °C for 5 min, raise the temperature to 80 °C, add styrene 2.2 times the mass of montmorillonite, 4-vinylaniline 0.5 times the mass of montmorillonite, benzoyl peroxide 0.06 times the mass of montmorillonite and divinylbenzene 0.3 times the mass of montmorillonite, stir for 2 h, raise the temperature to 90 °C and continue to stir for 1.1 h, naturally cool to room temperature and then filter, wash 3 times with deionized water, and dry at 55 °C for 25 h to obtain modified montmorillonite;

[0036] (4) Mix the modified montmorillonite, modified silicone resin and ethanol solution in a mass ratio of 1:0.1:0.2, ultrasonically disperse for 1 h, add modified silicon carbide whiskers with a mass 0.05 times that of the modified montmorillonite, stir at 900 rpm for 13 h, add composite ceramic powder with a mass 0.1 times that of the modified montmorillonite, use a disk granulator to stir and granulate at 45 r / min, and dry at 80 °C for 13 h to obtain a green body; Gradually heat the green body and then naturally cool it to room temperature to obtain lightweight composite porcelain clay.

[0037] Example 2:

[0038] A preparation method of lightweight composite porcelain clay, the preparation method of the lightweight composite porcelain clay includes the following preparation steps:

[0039] (1) Mix silicon carbide whiskers and 0.025 mol / L tris(hydroxymethyl)aminomethane aqueous solution in a mass ratio of 1:2000, ultrasonically disperse for 25 min, add 2 g / L hydrochloric acid dopamine, stir at 25 °C and 250 rpm for 16 h, then filter, wash 4 times with deionized water, and dry at 65 °C for 9 h to obtain modified silicon carbide whiskers;

[0040] (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran, stir at 30 °C and 250 rpm for 25 min, uniformly add a hydrochloric acid solution with a mass 5.5 times that of 3-glycidoxypropyl(dimethoxy)methylsilane within 7 min, continue to stir for 24 h, raise the temperature to 55 °C and continue to stir for 24 h, rotary evaporate for 1.5 h, add ethyl acetate for extraction, wash 4 times with saturated sodium hydroxide solution, and dry with anhydrous calcium chloride for 24 h to obtain silicone resin; Mix the silicone resin, 2-propene-1-boronic acid, chloroplatinic acid and toluene in a mass ratio of 1:1.5:0.02:5, stir at 70 °C and 150 rpm for 15 min in a nitrogen atmosphere, raise the temperature to 110 °C and continue to stir for 12 h, rotary evaporate at 70 °C for 1.5 h, and naturally cool to room temperature to obtain modified silicone resin;

[0041] (3) Mix montmorillonite, polyethylene glycol and deionized water in a mass ratio of 1:0.065:65, ultrasonically disperse at 25 °C for 10 min, raise the temperature to 85 °C, add styrene with a mass 2.3 times that of the montmorillonite, 4-vinyl aniline with a mass 1 time that of the montmorillonite, benzoyl peroxide with a mass 0.065 times that of the montmorillonite and divinylbenzene with a mass 0.4 times that of the montmorillonite, stir for 1.5 h, raise the temperature to 95 °C and continue to stir for 1 h, naturally cool to room temperature and then filter, wash 4 times with deionized water, and dry at 60 °C for 24 h to obtain modified montmorillonite;

[0042] (4) Mix the modified montmorillonite, modified silicone resin, and ethanol solution in a mass ratio of 1:0.15:0.25, ultrasonically disperse for 1.5 h, add modified silicon carbide whiskers at 0.055 times the mass of the modified montmorillonite, stir at 1000 rpm for 12 h, add composite ceramic powder at 0.15 times the mass of the modified montmorillonite, use a disk granulator to stir and granulate at 50 r / min, and dry at 85 °C for 12 h to obtain a green body; Gradually heat the green body and then naturally cool it to room temperature to obtain lightweight composite porcelain clay.

[0043] Example 3:

[0044] A preparation method of lightweight composite porcelain clay, the preparation method of the lightweight composite porcelain clay includes the following preparation steps:

[0045] (1) Mix silicon carbide whiskers and 0.03 mol / L tris(hydroxymethyl)aminomethane aqueous solution in a mass ratio of 1:2500, ultrasonically disperse for 30 min, add 3 g / L hydrochloric acid dopamine, stir at 30 °C and 300 rpm for 15 h and then filter, wash with deionized water 5 times, and dry at 70 °C for 8 h to obtain modified silicon carbide whiskers;

[0046] (2) Mix 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane, and tetrahydrofuran, stir at 35 °C and 300 rpm for 20 min, uniformly add a hydrochloric acid solution 6 times the mass of 3-glycidylpropyl(dimethoxy)methylsilane within 8 min, continue to stir for 23 h, raise the temperature to 60 °C and continue to stir for 23 h, rotary evaporate for 2 h, add ethyl acetate for extraction, wash with saturated sodium hydroxide solution 5 times, and dry with anhydrous calcium chloride for 25 h to obtain silicone resin; Mix the silicone resin, 2-propene-1-boronic acid, chloroplatinic acid, and toluene in a mass ratio of 1:2:0.03:6, stir at 75 °C and 200 rpm for 10 min in a nitrogen atmosphere, raise the temperature to 115 °C and continue to stir for 11 h, rotary evaporate at 75 °C for 1 h, and naturally cool to room temperature to obtain modified silicone resin;

[0047] (3) Mix montmorillonite, polyethylene glycol, and deionized water in a mass ratio of 1:0.07:70, ultrasonically disperse at 30 °C for 15 min, raise the temperature to 90 °C, add styrene at 2.4 times the mass of the montmorillonite, 4-vinyl aniline at 1.5 times the mass of the montmorillonite, benzoyl peroxide at 0.07 times the mass of the montmorillonite, and divinylbenzene at 0.5 times the mass of the montmorillonite, stir for 1 h, raise the temperature to 100 °C and continue to stir for 0.9 h, naturally cool to room temperature and then filter, wash with deionized water 5 times, and dry at 65 °C for 23 h to obtain modified montmorillonite;

[0048] (4) Mix the modified montmorillonite, modified silicone resin, and ethanol solution in a mass ratio of 1:0.2:0.3, ultrasonically disperse for 2 h, add modified silicon carbide whiskers at 0.06 times the mass of the modified montmorillonite, stir at 1100 rpm for 11 h, add composite ceramic powder at 0.2 times the mass of the modified montmorillonite, use a disk granulator to stir and granulate at 55 r / min, and dry at 90 °C for 11 h to obtain a green body; Gradually heat the green body and then naturally cool it to room temperature to obtain lightweight composite porcelain clay.

[0049] Comparative Example 1:

[0050] A preparation method of lightweight composite porcelain clay, the preparation method of the lightweight composite porcelain clay includes the following preparation steps:

[0051] (1) Mix 3-glycidylpropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane, and tetrahydrofuran, stir at 30 °C and 250 rpm for 25 min, uniformly add a hydrochloric acid solution at 5.5 times the mass of 3-glycidylpropyl(dimethoxy)methylsilane within 7 min, continue stirring for 24 h, raise the temperature to 55 °C and continue stirring for 24 h, rotary evaporate for 1.5 h, add ethyl acetate for extraction, wash 4 times with saturated sodium hydroxide solution, and dry for 24 h with anhydrous calcium chloride to obtain silicone resin; Mix the silicone resin, 2-propene-1-boronic acid, chloroplatinic acid, and toluene in a mass ratio of 1:1.5:0.02:5, stir at 70 °C and 150 rpm in a nitrogen atmosphere for 15 min, raise the temperature to 110 °C and continue stirring for 12 h, rotary evaporate at 70 °C for 1.5 h, and naturally cool to room temperature to obtain modified silicone resin;

[0052] (2) Mix montmorillonite, polyethylene glycol, and deionized water in a mass ratio of 1:0.065:65, ultrasonically disperse at 25 °C for 10 min, raise the temperature to 85 °C, add styrene at 2.3 times the mass of the montmorillonite, 4-vinyl aniline at 1 time the mass of the montmorillonite, benzoyl peroxide at 0.065 times the mass of the montmorillonite, and divinylbenzene at 0.4 times the mass of the montmorillonite, stir for 1.5 h, raise the temperature to 95 °C and continue stirring for 1 h, naturally cool to room temperature and then filter, wash 4 times with deionized water, and dry at 60 °C for 24 h to obtain modified montmorillonite;

[0053] (3) Mix the modified montmorillonite, modified silicone resin, and ethanol solution in a mass ratio of 1:0.15:0.25, ultrasonically disperse for 1.5 h, add silicon carbide whiskers at 0.055 times the mass of the modified montmorillonite, stir at 1000 rpm for 12 h, add composite ceramic powder at 0.15 times the mass of the modified montmorillonite, use a disk granulator to stir and granulate at 50 r / min, and dry at 85 °C for 12 h to obtain a green body; Gradually heat the green body and then naturally cool it to room temperature to obtain lightweight composite porcelain clay.

[0054] Comparative Example 2:

[0055] A preparation method of lightweight composite kaolin, the preparation method of the lightweight composite kaolin includes the following preparation steps:

[0056] (1) Mix silicon carbide whiskers and 0.025 mol / L tris(hydroxymethyl)aminomethane aqueous solution at a mass ratio of 1:2000, ultrasonically disperse for 25 min, add 2 g / L hydrochloric acid dopamine, stir at 25 °C and 250 rpm for 16 h, then filter, wash 4 times with deionized water, and dry at 65 °C for 9 h to obtain modified silicon carbide whiskers;

[0057] (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran, stir at 30 °C and 250 rpm for 25 min, uniformly add a hydrochloric acid solution 5.5 times the mass of 3-glycidoxypropyl(dimethoxy)methylsilane within 7 min, continue to stir for 24 h, raise the temperature to 55 °C and continue to stir for 24 h, rotary evaporate for 1.5 h, add ethyl acetate for extraction, wash 4 times with saturated sodium hydroxide solution, and dry with anhydrous calcium chloride for 24 h to obtain silicone resin;

[0058] (3) Mix montmorillonite, polyethylene glycol and deionized water at a mass ratio of 1:0.065:65, ultrasonically disperse at 25 °C for 10 min, raise the temperature to 85 °C, add styrene 2.3 times the mass of montmorillonite, 4-vinyl aniline 1 time the mass of montmorillonite, benzoyl peroxide 0.065 times the mass of montmorillonite and divinylbenzene 0.4 times the mass of montmorillonite, stir for 1.5 h, raise the temperature to 95 °C and continue to stir for 1 h, naturally cool to room temperature and then filter, wash 4 times with deionized water, and dry at 60 °C for 24 h to obtain modified montmorillonite;

[0059] (4) Mix the modified montmorillonite, silicone resin and ethanol solution at a mass ratio of 1:0.15:0.25, ultrasonically disperse for 1.5 h, add modified silicon carbide whiskers 0.055 times the mass of the modified montmorillonite, stir at 1000 rpm for 12 h, add composite ceramic powder 0.15 times the mass of the modified montmorillonite, use a disk granulator to stir and granulate at 50 r / min, and dry at 85 °C for 12 h to obtain a green body; Gradually raise the temperature of the green body and then naturally cool to room temperature to obtain lightweight composite kaolin.

[0060] Comparative Example 3:

[0061] A preparation method of lightweight composite kaolin, the preparation method of the lightweight composite kaolin includes the following preparation steps:

[0062] (1) Mix silicon carbide whiskers and 0.025 mol / L tris(hydroxymethyl)aminomethane aqueous solution in a mass ratio of 1:2000, ultrasonically disperse for 25 min, add 2 g / L dopamine hydrochloride, stir at 25 °C and 250 rpm for 16 h, then filter, wash 4 times with deionized water, and dry at 65 °C for 9 h to obtain modified silicon carbide whiskers;

[0063] (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran, stir at 30 °C and 250 rpm for 25 min, uniformly add a hydrochloric acid solution 5.5 times the mass of 3-glycidoxypropyl(dimethoxy)methylsilane within 7 min, continue stirring for 24 h, raise the temperature to 55 °C and continue stirring for 24 h, rotary evaporate for 1.5 h, add ethyl acetate for extraction, wash 4 times with saturated sodium hydroxide solution, and dry with anhydrous calcium chloride for 24 h to obtain silicone resin; Mix the silicone resin, 2-propen-1-boronic acid, chloroplatinic acid and toluene in a mass ratio of 1:1.5:0.02:5, stir at 70 °C and 150 rpm in a nitrogen atmosphere for 15 min, raise the temperature to 110 °C and continue stirring for 12 h, rotary evaporate at 70 °C for 1.5 h, and naturally cool to room temperature to obtain modified silicone resin;

[0064] (3) Mix montmorillonite, modified silicone resin and ethanol solution in a mass ratio of 1:0.15:0.25, ultrasonically disperse for 1.5 h, add modified silicon carbide whiskers 0.055 times the mass of montmorillonite, stir at 1000 rpm for 12 h, add composite ceramic powder 0.15 times the mass of montmorillonite, use a disk granulator to stir and granulate at 50 r / min, and dry at 85 °C for 12 h to obtain a green body; Gradually raise the temperature of the green body and then naturally cool to room temperature to obtain lightweight composite porcelain clay.

[0065] Test Examples

[0066] 1. Plasticity

[0067] Test method: Take spherical samples of the same size from the green bodies obtained in each example and the comparative example, and according to the plasticity index method, test the plasticity index = (sample diameter - height at which cracks appear) × load.

[0068] 2. Heat preservation

[0069] Test method: Take the same samples from the lightweight composite porcelain clay obtained in each example and the comparative example, and according to GB / T11205, use a TC3000 type thermal conductivity measuring instrument to measure the thermal conductivity.

[0070] 3. Crack resistance

[0071] Test method: Samples of 2 cm × 2 cm × 2 cm in size were taken from the lightweight composite kaolin obtained in each example and the comparative examples respectively, and a digital display hydraulic pressure testing machine (YES-600) was used to measure the compressive strength of the specimens under the condition that the pressurization rate was 0.1 kN / s.

[0072] Table 1 below gives the analysis results of the plasticity, heat preservation and crack resistance of the lightweight composite kaolin of Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0073] Table 1

[0074]

[0075] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 1, it can be found that the lightweight composite kaolin prepared by the present invention has good plasticity, heat preservation and crack resistance.

[0076] By comparison, Examples 1, 2, and 3 have higher plastic indexes and lower thermal conductivities than Comparative Example 1, indicating that a layer of polydopamine is formed on the surface of silicon carbide whiskers. The phenolic hydroxyl groups can not only form reversible crosslinks with boric acid, but also form covalent crosslinks with amino groups and coordination bonds with metals, improving the plasticity of lightweight composite kaolin; during the sintering process, the carbonization of polydopamine can also generate pores, improving the heat preservation of lightweight composite kaolin.

[0077] By comparison, Examples 1, 2, and 3 have higher plastic indexes and compressive strengths than Comparative Example 2, indicating that 2-acryloyl-1-boronic acid is grafted by hydrosilylation to introduce a boric acid structure, forming a reversible borate crosslinking network at low temperature and undergoing a carbothermal reduction reaction with free carbon during high-temperature calcination to fill and support the pore structure, improving the plasticity and crack resistance of lightweight composite kaolin.

[0078] By comparison, Examples 1, 2, and 3 have higher plastic indexes and lower thermal conductivities than Comparative Example 3, indicating that polyethylene glycol and styrene cooperate to form pores during high-temperature calcination, improving the heat preservation of lightweight composite kaolin; at the same time, 4-vinyl aniline participating in surface polymerization introduces an amino group, which reacts with the epoxy group in the silicone resin at low temperature to form a chemical bond and a hydroxyl structure that can be removed at high temperature, further improving the plasticity and heat preservation of lightweight composite kaolin.

[0079] The specific embodiments described above further elaborate on the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a lightweight composite kaolin, characterized in that, It includes the following preparation steps: (1) Mix silicon carbide whiskers and dopamine hydrochloride to obtain modified silicon carbide whiskers; (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and hydrochloric acid solution to obtain silicone resin; Mix the silicone resin, 2-propen-1-boronic acid and chloroplatinic acid to obtain modified silicone resin; (3) Mix montmorillonite, polyethylene glycol, styrene, 4-vinylaniline, benzoyl peroxide and divinylbenzene to obtain modified montmorillonite; (4) Gradually increase the temperature for sintering after mixing the modified montmorillonite, modified silicone resin, modified silicon carbide whiskers and composite ceramic powder to obtain lightweight composite porcelain clay.

2. The preparation method of a lightweight composite kaolin according to claim 1, wherein It includes the following preparation steps: (1) Mix silicon carbide whiskers and 0.02 - 0.03 mol / L tris(hydroxymethyl)aminomethane aqueous solution at a mass ratio of 1:(1500 - 2500), ultrasonically disperse for 20 - 30 min, add 1 - 3 g / L dopamine hydrochloride, stir at 20 - 30 °C and 200 - 300 rpm for 15 - 17 h, then filter, wash with deionized water 3 - 5 times, and dry at 60 - 70 °C for 8 - 10 h to obtain modified silicon carbide whiskers; (2) Mix 3-glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane and tetrahydrofuran, stir at 25 - 35 °C and 200 - 300 rpm for 20 - 30 min, uniformly add hydrochloric acid solution 5 - 6 times the mass of 3-glycidoxypropyl(dimethoxy)methylsilane within 6 - 8 min, continue to stir for 23 - 25 h, raise the temperature to 50 - 60 °C and continue to stir for 23 - 25 h, rotary evaporate for 1 - 2 h, add ethyl acetate for extraction, wash with saturated sodium hydroxide solution 3 - 5 times, and dry with anhydrous calcium chloride for 23 - 25 h to obtain silicone resin; Mix the silicone resin, 2-propen-1-boronic acid, chloroplatinic acid and toluene at a mass ratio of 1:(1 - 2):(0.01 - 0.03):(4 - 6), stir in a nitrogen atmosphere at 65 - 75 °C and 100 - 200 rpm for 10 - 20 min, raise the temperature to 105 - 115 °C and continue to stir for 11 - 13 h, rotary evaporate at 65 - 75 °C for 1 - 2 h, and naturally cool to room temperature to obtain modified silicone resin; (3) Mix montmorillonite, polyethylene glycol and deionized water at a mass ratio of 1:(0.06 - 0.07):(60 - 70), ultrasonically disperse at 20 - 30 °C for 5 - 15 min, raise the temperature to 80 - 90 °C, add styrene 2.2 - 2.4 times the mass of montmorillonite, 4-vinylaniline 0.5 - 1.5 times the mass of montmorillonite, benzoyl peroxide 0.06 - 0.07 times the mass of montmorillonite and divinylbenzene 0.3 - 0.5 times the mass of montmorillonite, stir for 1 - 2 h, raise the temperature to 90 - 100 °C and continue to stir for 0.9 - 1.1 h, naturally cool to room temperature and then filter, wash with deionized water 3 - 5 times, and dry at 55 - 65 °C for 23 - 25 h to obtain modified montmorillonite; (4) Mix the modified montmorillonite, modified silicone resin, and ethanol solution in a mass ratio of 1:(0.1 - 0.2):(0.2 - 0.3), ultrasonically disperse for 1 - 2 h, add modified silicon carbide whiskers in an amount 0.05 - 0.06 times the mass of the modified montmorillonite, stir at 900 - 1100 rpm for 11 - 13 h, add composite ceramic powder in an amount 0.1 - 0.2 times the mass of the modified montmorillonite, use a disk granulator to stir and granulate at 45 - 55 r / min, and dry at 80 - 90 °C for 11 - 13 h to obtain a green body; Gradually heat the green body and then naturally cool it to room temperature to obtain lightweight composite porcelain clay.

3. The preparation method of a lightweight composite kaolin according to claim 2, characterized in that The mixing of 3 - glycidoxypropyl(dimethoxy)methylsilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldiethoxysilane, and tetrahydrofuran in step (2) is carried out in a mass ratio of 1:2:0.7:0.8:

19.

4. The preparation method of a lightweight composite kaolin according to claim 2, characterized in that, The pH of the hydrochloric acid solution in step (2) is 1.

5. The preparation method of a lightweight composite kaolin according to claim 2, characterized in that The volume fraction of the ethanol solution in step (4) is 50%.

6. The preparation method of a lightweight composite kaolin according to claim 2, characterized in that, The composite ceramic powder in step (4) is obtained by mixing potassium feldspar powder and white gangue powder in a mass ratio of 1:0.3 and milling with corundum balls on a planetary ball mill for 4 h.

7. The preparation method of a lightweight composite kaolin according to claim 2, characterized in that The gradient heating in step (4) is to heat at a rate of 5 °C / min to 400 °C for preheating for 60 min, heat at a rate of 4 °C / min to 1000 °C, hold for 2 h, and then heat at a rate of 2 °C / min to 1450 °C and hold for 4 h.

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