A high-strength building ceramic material and preparation method thereof

Abstract

The present invention belongs to the technical field of ceramic materials, and specifically relates to a high-strength building ceramic material and a preparation method thereof. A high-strength building ceramic material comprises the following raw materials in parts by weight: 20-30 parts of potassium feldspar, 15-23 parts of kaolin, 37-45 parts of solid waste-based silicon carbide, 1-4 parts of talc, 3-8 parts of modified mullite whiskers, and 2-5 parts of filler; the preparation process of the modified mullite whiskers is as follows: (1) adding mullite whiskers to an ethanol aqueous solution containing a silane coupling agent, heating and reacting to obtain pretreated mullite whiskers; (2) adding the mullite whiskers pretreated in step (1) to a nickel sulfate aqueous solution, then adding triethylamine and sodium thiosulfate, heating and reacting to obtain modified mullite whiskers. The combination of the above raw material components helps to prepare a high-strength ceramic material, and can improve the thermal conductivity and enhance the thermal conductivity effect, and is suitable for ordinary home decoration and high thermal conductivity floor heating ceramic tiles.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and particularly relates to a high-strength building ceramic material and a preparation method thereof. Background Art

[0002] With the rapid development of the construction industry, the requirements for the performance of building materials are increasing. As an important building material, building ceramics are widely used in building exterior walls, floors, decorations and other fields. Ordinary building ceramics usually use natural minerals such as clay, feldspar, quartz as raw materials, and are sintered at high temperatures to form a dense structure, but their flexural strength is generally low and their thermal conductivity is poor, making it difficult to meet the needs of high-intensity load-bearing scenarios or high-thermal conductivity floor heating systems. In addition, the low thermal conductivity of traditional ceramics leads to insufficient heat energy transfer efficiency, which significantly affects the heating effect and energy consumption economy. Therefore, the research and development of high-strength building ceramic materials has become a research hotspot in the current field of building materials.

[0003] In recent years, the research on high-strength building ceramic materials has made significant progress. Researchers have successfully improved the strength, hardness, wear resistance and other properties of ceramic materials by optimizing material composition and improving preparation processes. For example, by introducing nanomaterials and fiber reinforcement technologies, the mechanical properties of ceramic materials have been effectively improved. Solid waste-based silicon carbide, as a new type of ceramic reinforcement material, not only realizes the resource utilization of solid waste and reduces production costs, but also gives ceramic materials excellent mechanical properties. At present, the application research of solid waste-based silicon carbide in building ceramics is still in its infancy. The existing high-strength building ceramic technology has the following core problems: (1) It is difficult to balance strength and thermal conductivity, and the introduction of fillers often leads to a decrease in thermal conductivity; (2) The utilization of solid waste raw materials faces challenges in sintering performance and impurity control.

[0004] To address the above problems, it is urgent to develop a new type of composite ceramic system to break through the performance bottleneck by optimizing the raw material ratio, high-value utilization of solid waste and improving the preparation process. Summary of the Invention

[0005] A first object of the present invention is to provide a high-strength building ceramic material.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A high-strength building ceramic material comprises the following raw materials in parts by weight: 20-30 parts of potassium feldspar, 15-23 parts of kaolin, 37-45 parts of solid waste-based silicon carbide, 1-4 parts of talc, 3-8 parts of modified mullite whiskers, and 2-5 parts of filler;

[0008] The preparation process of the modified mullite whisker is as follows:

[0009] (1) adding mullite whiskers to an ethanol aqueous solution containing a silane coupling agent, heating the solution to react, and obtaining pretreated mullite whiskers;

[0010] (2) Adding the mullite whiskers pretreated in step (1) to a nickel sulfate aqueous solution, and then adding triethylamine and sodium thiosulfate, heating the reaction to obtain modified mullite whiskers.

[0011] Furthermore, in step (1), the amount ratio of the mullite whisker, the silane coupling agent and the ethanol aqueous solution is 1g:0.05-0.15g:10mL; the volume ratio of ethanol to water in the ethanol aqueous solution is 4:1; the temperature of the heating reaction is 55-65°C, and the time is 12-18h.

[0012] Furthermore, the diameter of the mullite whisker is 1-2 microns, and the aspect ratio is 20-30; and the silane coupling agent is KH550 or KH560.

[0013] Furthermore, in step (2), the mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine and sodium thiosulfate is 1:(6-12):(1-2):(3-5); the mass concentration of the nickel sulfate aqueous solution is 3-12%; the temperature of the heating reaction is 90-100°C, and the time is 1.5-3.5h.

[0014] Furthermore, the preparation process of the filler is as follows: graphene is dispersed in water, polyvinyl alcohol and konjac glucomannan are added, ultrasonic dispersion is performed, and spray drying is performed to obtain the filler.

[0015] Furthermore, the mass ratio of the graphene, polyvinyl alcohol, konjac glucomannan and water is 1: (3-5): (2-3): (16-20).

[0016] Furthermore, the preparation process of the solid waste-based silicon carbide is as follows: photovoltaic cutting waste is ground, sieved, pickled, and dried to obtain solid waste-based silicon carbide.

[0017] Furthermore, the solvent used for pickling is a hydrofluoric acid solution with a mass concentration of 6-10%; and the pickling time is 10-12 hours.

[0018] The solid waste-based silicon carbide of the present invention is prepared by a mechanical grinding-spray powdering process. Mechanical grinding can control the silicon carbide particle size to be lower than 0.06 mm, reduce stress concentration, and accelerate the solid phase reaction speed.

[0019] The second object of the present invention is to provide a method for preparing a high-strength building ceramic material.

[0020] In order to achieve the above object, the technical solution adopted by the present invention is:

[0021] A method for preparing a high-strength building ceramic material comprises the following steps:

[0022] a. Wet ball milling of potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and fillers, and sieving to remove iron to obtain a slurry;

[0023] b. Inject the slurry into the mold and let it stand at room temperature for 28 hours; dry it to set it; then perform gradient sintering to obtain it.

[0024] Furthermore, the gradient sintering is first kept at 800°C for 2-3 hours; then heated to 1150°C at a heating rate of 20°C / min; after reaching the target temperature, pressurized to 2-6MPa and kept warm for 1-2 hours.

[0025] Compared with the prior art, the beneficial effects of the present invention are mainly:

[0026] 1. The present invention provides a high-strength building ceramic material. The modified mullite whiskers introduced in the present invention are modified by forming a nickel sulfide layer on the surface of the mullite whiskers. On the one hand, the nickel sulfide coating reaches a molten state during the sintering process, reducing bubbles and bulging in the ceramic matrix, improving the thermal conductivity and density of the ceramic material, and improving the mechanical strength of the ceramic material. On the other hand, the surface roughness of the mullite whiskers is increased, and the mechanical interlocking effect between the mullite whiskers and other components is improved, thereby improving the uniformity of the mullite whisker dispersion.

[0027] The filler prepared by the present invention forms a flexible network structure by coating polyvinyl alcohol and konjac glucomannan on the surface of graphene, thereby preventing graphene from agglomerating and improving the dispersion strengthening effect of graphene in ceramics. In combination with modified mullite whiskers, the filler improves the thermal conductivity and mechanical strength of the ceramic material.

[0028] 2. The present invention provides a method for preparing high-strength building ceramic materials. This method achieves densification and balanced overall performance of the ceramic material through a gradient sintering process involving low-temperature pre-firing, rapid heating, and constant pressure holding. The pre-firing stage helps remove organic matter and prevents the formation of bubbles. The rapid heating stage utilizes a slightly oxidizing atmosphere in the kiln to prevent excessive SiC oxidation to SiO2. The high-temperature pressure holding stage promotes grain boundary diffusion, helping to increase the density of the ceramic material.

[0029] 3. The present invention not only solves the problem of insufficient strength of ceramic materials, but also realizes the resource utilization of solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the modified mullite whisker obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be further described below in conjunction with specific embodiments. However, it should be understood by those skilled in the art that the following examples are only intended to illustrate the present invention and should not be construed as limiting the present invention. Specific conditions not specified in the examples are to be followed according to conventional conditions or the conditions recommended by the manufacturer. All reagents or instruments used, unless otherwise specified, are conventional products obtained from commercial channels.

[0032] The diameter of the mullite whiskers is 1-2 microns, with an aspect ratio of 20-30; the silane coupling agent is KH550 or KH560. Photovoltaic cutting waste is waste generated during the silicon wafer production process.

[0033] Example 1

[0034] A high-strength building ceramic material comprises the following raw materials in parts by weight: 25 parts of potassium feldspar, 20 parts of kaolin, 40 parts of solid waste-based silicon carbide, 3 parts of talc, 5 parts of modified mullite whiskers, and 4 parts of filler;

[0035] The preparation process of the modified mullite whisker is as follows:

[0036] (1) An ethanol-water solution is prepared by mixing anhydrous ethanol and water in a volume ratio of 4:1, and mullite whiskers are added to the ethanol-water solution containing KH550, wherein the mass ratio of the mullite whiskers to KH550 is 1:0.1, and the amount ratio of the mullite whiskers to the ethanol-water solution is 1 g:10 mL; the reaction is heated at 60°C for 16 hours, and the reaction solution is filtered, washed, and dried to obtain pretreated mullite whiskers;

[0037] (2) preparing a nickel sulfate aqueous solution with a mass concentration of 5%, adding the mullite whiskers pretreated in step (1) to the nickel sulfate aqueous solution, and then adding triethylamine and sodium thiosulfate, wherein the mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine and sodium thiosulfate is 1:10:1.5:4; heating the reaction at 95°C for 2.5 hours; and then filtering, washing and drying the reaction solution to obtain modified mullite whiskers.

[0038] The preparation process of the filler is as follows: graphene is dispersed in water, and then polyvinyl alcohol and konjac glucomannan are added, wherein the mass ratio of graphene, polyvinyl alcohol, konjac glucomannan and water is 1:4:2.5:18; ultrasonic dispersion is uniform, and spray drying is performed at 75°C to obtain the filler.

[0039] The preparation process of solid waste-based silicon carbide is as follows: take photovoltaic cutting waste, grind it and sieve it, then put it into a 10% hydrofluoric acid solution, stir it evenly, let it stand at room temperature for 12 hours, then filter the solution after standing, and dry the filtered solid to obtain solid waste-based silicon carbide.

[0040] The method for preparing the above-mentioned high-strength building ceramic material comprises the following steps:

[0041] a. Potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler are wet-milled to obtain a slurry;

[0042] b. Inject the slurry into the mold and let it stand at room temperature for 28 hours; then dry and shape it; keep it at 800℃ for 2.5 hours; then heat it to 1150℃ at a heating rate of 20℃ / min. After reaching the target temperature, pressurize it to 5MPa and keep it at this temperature for 1.5 hours.

[0043] Example 2

[0044] A high-strength building ceramic material comprises the following raw materials in parts by weight: 20 parts of potassium feldspar, 15 parts of kaolin, 37 parts of solid waste-based silicon carbide, 1 part of talc, 3 parts of modified mullite whiskers, and 2 parts of filler;

[0045] The preparation process of the modified mullite whisker is as follows:

[0046] (1) An ethanol-water solution is prepared by mixing anhydrous ethanol and water in a volume ratio of 4:1, and mullite whiskers are added to the ethanol-water solution containing KH550, wherein the mass ratio of the mullite whiskers to KH550 is 1:0.05, and the amount ratio of the mullite whiskers to the ethanol-water solution is 1 g:10 mL; the reaction is heated at 55° C. for 18 h, and the reaction solution is filtered, washed, and dried to obtain pretreated mullite whiskers;

[0047] (2) preparing a nickel sulfate aqueous solution with a mass concentration of 3%, adding the mullite whiskers pretreated in step (1) to the nickel sulfate aqueous solution, and then adding triethylamine and sodium thiosulfate, wherein the mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine and sodium thiosulfate is 1:6:1:3; heating the reaction at 90°C for 3.5h; and then filtering, washing and drying the reaction solution to obtain modified mullite whiskers.

[0048] The preparation process of the filler is as follows: graphene is dispersed in water, and then polyvinyl alcohol and konjac glucomannan are added, wherein the mass ratio of graphene, polyvinyl alcohol, konjac glucomannan and water is 1:3:2:16; ultrasonic dispersion is performed uniformly, and spray drying is performed at 80°C to obtain the filler.

[0049] The preparation process of solid waste-based silicon carbide is as follows: take photovoltaic cutting waste, grind it, sieve it, put it into a 10% hydrofluoric acid solution, stir it evenly, let it stand at room temperature for 12 hours, then filter the solution after standing, and dry the filtered solid to obtain solid waste-based silicon carbide.

[0050] The method for preparing the above-mentioned high-strength building ceramic material comprises the following steps:

[0051] a. Potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler are wet-milled to obtain a slurry;

[0052] b. Inject the slurry into the mold and let it stand at room temperature for 28 hours; dry and shape it; keep it at 800℃ for 2 hours; then heat it to 1150℃ at a heating rate of 20℃ / min. After reaching the target temperature, pressurize it to 3MPa and keep it at this temperature for 2 hours.

[0053] Example 3

[0054] A high-strength building ceramic material comprises the following raw materials in parts by weight: 30 parts of potassium feldspar, 23 parts of kaolin, 45 parts of solid waste-based silicon carbide, 4 parts of talc, 8 parts of modified mullite whiskers, and 5 parts of filler;

[0055] The preparation process of the modified mullite whisker is as follows:

[0056] (1) An ethanol-water solution was prepared by mixing anhydrous ethanol and water in a volume ratio of 4:1, and mullite whiskers were added to the ethanol-water solution containing KH550, wherein the mass ratio of the mullite whiskers to KH550 was 1:0.15, and the amount ratio of the mullite whiskers to the ethanol-water solution was 1 g:10 mL; the reaction was heated at 65°C for 12 hours, and the reaction solution was filtered, washed, and dried to obtain pretreated mullite whiskers;

[0057] (2) preparing an 8% nickel sulfate aqueous solution, adding the mullite whiskers pretreated in step (1) to the nickel sulfate aqueous solution, and then adding triethylamine and sodium thiosulfate, wherein the mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine and sodium thiosulfate is 1:12:2:5; heating the reaction at 100° C. for 1.5 h; and then filtering, washing and drying the reaction solution to obtain modified mullite whiskers.

[0058] The preparation process of the filler is as follows: graphene is dispersed in water, and then polyvinyl alcohol and konjac glucomannan are added, wherein the mass ratio of graphene, polyvinyl alcohol, konjac glucomannan and water is 1:5:3:20; ultrasonic dispersion is performed uniformly, and spray drying is performed at 85°C to obtain the filler.

[0059] The preparation process of solid waste-based silicon carbide is as follows: take photovoltaic cutting waste, grind it, sieve it, put it into a 10% hydrofluoric acid solution, stir it evenly, let it stand at room temperature for 12 hours, then filter the solution after standing, and dry the filtered solid to obtain solid waste-based silicon carbide.

[0060] The method for preparing the above-mentioned high-strength building ceramic material comprises the following steps:

[0061] a. Potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler are wet-milled to obtain a slurry;

[0062] b. Inject the slurry into the mold and let it stand at room temperature for 28 hours; dry and shape it; keep it at 800℃ for 3 hours; then heat it to 1150℃ at a heating rate of 20℃ / min. After reaching the target temperature, pressurize it to 6MPa and keep it at this temperature for 1 hour.

[0063] Comparative Example 1

[0064] Comparative Example 1 is substantially the same as Example 1, except that the modified mullite whiskers are replaced with mullite whiskers and nickel sulfide (mass ratio is 1:4).

[0065] Comparative Example 2

[0066] Comparative Example 2 is substantially the same as Example 1, except that the filler is replaced with graphene and konjac glucomannan (mass ratio is 1:2.5).

[0067] Figure 1 This is the SEM image of the modified mullite whisker of the present invention. It can be observed that the diameter of the modified mullite whisker is relatively uniform, and a relatively dense nickel sulfide layer is uniformly deposited on the surface, indicating that nickel sulfide is successfully coated on the surface of the mullite whisker.

[0068] Test Example 1

[0069] In order to characterize the architectural ceramic materials of Examples 1-3 and Comparative Examples 1-2 of the present invention, the following performance tests were performed:

[0070] (1) Thermal conductivity test: The thermal conductivity of each group of samples in Examples 1-3 and Comparative Examples 1-2 was tested using the hot wire method. Each group was tested three times, and the average value was taken as the final test result. The experimental results are shown in Table 1.

[0071] (2) Flexural strength test: The flexural strength of each group of samples of Examples 1-3 and Comparative Examples 1-2 was tested on a universal mechanical testing machine using a three-point bending method. The experimental results are shown in Table 1.

[0072] Table 1

[0073]

[0074] A higher thermal conductivity indicates a stronger material's thermal conductivity, meaning that heat transfer is faster within the material. As shown in Table 1, the thermal conductivity and flexural strength of the ceramic tiles of Examples 1-3 of the present invention are higher than those of Comparative Examples 1 and 2. This demonstrates that the ceramic tiles of the present invention possess excellent thermal conductivity and mechanical strength, making them suitable for general home decoration and high-thermal-conductivity floor heating ceramic tiles.

[0075] Compared with Example 1, Comparative Example 1 replaces the modified mullite whiskers with mullite whiskers and nickel sulfide; Comparative Example 2 replaces the filler with graphene and konjac glucomannan, and the thermal conductivity and flexural strength of the ceramic material are both deteriorated, indicating that the introduction of modified mullite whiskers and fillers can improve the mechanical strength and thermal conductivity of ceramics. When used as floor heating ceramic tiles, it can enhance thermal conductivity, help to increase the temperature of the room, and provide insulation, which is of great significance for improving the comprehensive performance of ceramic tiles.

[0076] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the same. The basic principles and main features of the present invention have been described above using specific implementation schemes. Modifications or substitutions may be made based on the present invention, but such modifications or substitutions do not detract from the essence of the corresponding technical solutions from the scope of protection claimed by the present invention.

Claims

1. A high-strength building ceramic material, characterized in that: The invention comprises the following raw materials in parts by weight: 20-30 parts of potassium feldspar, 15-23 parts of kaolin, 37-45 parts of solid waste-based silicon carbide, 1-4 parts of talc, 3-8 parts of modified mullite whiskers, and 2-5 parts of filler; The preparation process of the modified mullite whisker is as follows: (1) adding mullite whiskers to an ethanol aqueous solution containing a silane coupling agent, heating the solution to react, and obtaining pretreated mullite whiskers; (2) adding the mullite whiskers pretreated in step (1) to a nickel sulfate aqueous solution, then adding triethylamine and sodium thiosulfate, and heating the reaction to obtain modified mullite whiskers; The preparation process of the filler is as follows: graphene is dispersed in water, polyvinyl alcohol and konjac glucomannan are added, ultrasonic dispersion is performed, and spray drying is performed to obtain the filler; The mass ratio of graphene, polyvinyl alcohol, konjac glucomannan and water is 1: (3-5): (2-3): (16-20); The preparation process of the solid waste-based silicon carbide is as follows: photovoltaic cutting waste is ground, sieved, pickled, and dried to obtain solid waste-based silicon carbide.

2. A high-strength building ceramic material according to claim 1, characterized in that: In step (1), the amount ratio of the mullite whisker, the silane coupling agent and the ethanol aqueous solution is 1g:0.05-0.15g:10mL; the volume ratio of ethanol to water in the ethanol aqueous solution is 4:1; the temperature of the heating reaction is 55-65°C, and the time is 12-18h.

3. The high-strength building ceramic material according to claim 1, characterized in that: The diameter of the mullite whisker before pretreatment is 1-2 microns, and the aspect ratio is 20-30; the silane coupling agent is KH550 or KH560.

4. The high-strength building ceramic material according to claim 1, characterized in that: In step (2), the mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine and sodium thiosulfate is 1: (6-12): (1-2): (3-5); the mass concentration of the nickel sulfate aqueous solution is 3-12%; the temperature of the heating reaction is 90-100° C., and the time is 1.5-3.5 hours.

5. The high-strength building ceramic material according to claim 1, characterized in that: The solvent used for pickling is a hydrofluoric acid solution with a mass concentration of 6-10%; the pickling time is 10-12 hours.

6. The method for preparing a high-strength building ceramic material according to any one of claims 1 to 5, characterized in that: The steps include: a. The potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler are wet ball-milled, deironed, and sieved to obtain a slurry; b. Inject the slurry into the mold and let it stand at room temperature for 28 hours; dry it to set it; then perform gradient sintering to obtain it.

7. The method for preparing a high-strength building ceramic material according to claim 6, characterized in that: The gradient sintering is firstly kept at 800°C for 2-3 hours; then heated to 1150°C at a heating rate of 20°C / min; after reaching the target temperature, pressurized to 2-6MPa and kept at this temperature for 1-2 hours.

Images