High-strength building ceramic material and preparation method thereof

Abstract

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. The high-strength building ceramic material is prepared from the following raw materials in parts by weight: 20 to 30 parts of potassium feldspar, 15 to 23 parts of kaolin, 37 to 45 parts of solid waste-based silicon carbide, 1 to 4 parts of talc, 3 to 8 parts of modified mullite whisker and 2 to 5 parts of filler, a preparation process of the modified mullite crystal whiskers comprises the following steps: (1) adding mullite crystal whiskers into an ethanol water solution containing a silane coupling agent, and heating for reaction to obtain pretreated mullite crystal whiskers; and (2) adding the mullite whiskers pretreated in the step (1) into a nickel sulfate aqueous solution, then adding triethylamine and sodium thiosulfate, and carrying out a heating reaction to obtain the modified mullite whiskers. After the raw material components are combined, preparation of a high-strength ceramic material is facilitated, the heat conductivity coefficient can be increased, the heat conduction effect can be enhanced, and the ceramic material is suitable for common home decoration and high-heat-conductivity floor heating ceramic tiles.

Description

Technical Field

[0001] The present 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 day by day. As an important building material, architectural ceramics are widely used in the fields of building exterior walls, floors, decoration, etc. Ordinary architectural ceramics usually use natural minerals such as clay, feldspar, and quartz as raw materials and are sintered at high temperature to form a dense structure. However, their flexural strength is generally low and their thermal conductivity is poor, making it difficult to meet the requirements of high-strength load-bearing scenarios or high-thermal-conductivity floor heating systems. Moreover, due to the low thermal conductivity of traditional ceramics, the heat transfer efficiency is insufficient, significantly affecting 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, significant progress has been made in the research of high-strength building ceramic materials. Researchers have successfully improved the strength, hardness, wear resistance and other properties of ceramic materials by optimizing the material composition, improving the preparation process and other means. For example, by introducing nanomaterials, fiber reinforcement and other technologies, the mechanical properties of ceramic materials have been effectively improved. As a new type of ceramic reinforcement material, waste-based silicon carbide not only realizes the resource utilization of solid waste, reduces the production cost, but also endows the ceramic material with excellent mechanical properties. At present, the application research of waste-based silicon carbide in architectural ceramics is still in its infancy. The existing high-strength building ceramic technologies have 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 waste raw materials faces challenges in sintering performance and impurity control.

[0004] In view of the above problems, it is urgent to develop a new 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] The 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: A high-strength building ceramic material, comprising the following raw materials in parts by weight: 20-30 parts of potassium feldspar, 15-23 parts of kaolin, 37-45 parts of 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) Add mullite whiskers to an ethanol aqueous solution containing a silane coupling agent, heat and react to obtain pretreated mullite whiskers; (2) Add the mullite whiskers pretreated in step (1) to an aqueous solution of nickel sulfate, then add triethylamine and sodium thiosulfate, and obtain modified mullite whiskers after heating and reacting.

[0007] Further, in step (1), the dosage ratio of the mullite whiskers, silane coupling agent, and ethanol aqueous solution is 1 g: 0.05 - 0.15 g: 10 mL; 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 - 18 h.

[0008] Further, the diameter of the mullite whiskers is 1 - 2 microns, and the aspect ratio is 20 - 30; the silane coupling agent is KH550 or KH560.

[0009] Further, 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 h.

[0010] Further, the preparation process of the filler is as follows: Take graphene and disperse it in water, then add polyvinyl alcohol and konjac glucomannan, ultrasonically disperse evenly, and spray dry to obtain the filler.

[0011] Further, the mass ratio of graphene, polyvinyl alcohol, konjac glucomannan, and water is 1: (3 - 5): (2 - 3): (16 - 20).

[0012] Further, the preparation process of the solid waste-based silicon carbide is as follows: Grind the photovoltaic cutting waste, sieve it, pickle it with acid, and dry it to obtain the solid waste-based silicon carbide.

[0013] Further, the solvent used for pickling is a hydrofluoric acid solution with a mass concentration of 6 - 10%; the pickling time is 10 - 12 h.

[0014] The solid waste-based silicon carbide of the present invention is prepared by a mechanical grinding - spray powder making process. Mechanical grinding can control the particle size of silicon carbide below 0.06 mm, reduce the concentration of stress, and accelerate the solid-phase reaction rate.

[0015] The second object of the present invention is to provide a preparation method of a high-strength building ceramic material.

[0016] To achieve the above object, the technical solution adopted by the present invention is: A preparation method of a high-strength building ceramic material, comprising the following steps: a. Wet ball mill potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler, remove iron and sieve to obtain a slurry; b. Inject the slurry into the mold, let it stand at room temperature for 28 h; dry and shape it; then carry out gradient sintering; thus obtained.

[0017] Further, the gradient sintering is carried out by first holding at 800 °C for 2 - 3 h; then heating up to 1150 °C at a heating rate of 20 °C / min, pressurizing to 2 - 6 MPa after reaching the target temperature, and holding for 1 - 2 h.

[0018] Compared with the prior art, the beneficial effects of the present invention mainly lie in: 1. The present invention provides a high-strength building ceramic material; the modified mullite whiskers introduced in the present invention: a nickel sulfide layer is formed on the surface of the mullite whiskers for modification. On the one hand, during the sintering process, the nickel sulfide coating reaches a molten state, reducing bubbles and bulges in the ceramic matrix, improving the thermal conductivity and densification of the ceramic material, and improving the mechanical strength of the ceramic material; on the other hand, it can also increase the surface roughness of the mullite whiskers and the mechanical interlocking effect between the mullite whiskers and other components, improving the uniformity of the dispersion of the mullite whiskers.

[0019] The filler prepared by the present invention: by coating polyvinyl alcohol and konjac glucomannan on the surface of graphene, a flexible network structure is formed, avoiding the agglomeration of graphene, improving the dispersion strengthening effect of graphene in the ceramic, and cooperating with the modified mullite whiskers to improve the thermal conductivity and mechanical strength of the ceramic material.

[0020] 2. The present invention provides a preparation method of a high-strength building ceramic material. Through the regulation of the gradient sintering process of low-temperature pre-sintering, rapid heating, and constant-pressure heat preservation, the densification of the ceramic material and the balance of comprehensive properties are realized. Among them, in the pre-sintering stage, it helps to remove organic substances and avoid the generation of bubbles. In the rapid heating stage, the kiln adopts a slightly oxidizing atmosphere, which can prevent excessive oxidation of SiC into SiO2; in the high-temperature pressure-holding stage, it promotes the diffusion of grain boundaries and helps to improve the density of the ceramic material.

[0021] 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

[0022] Figure 1 It is the SEM diagram of the modified mullite whiskers obtained in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following further describes the technical solutions of the present invention in conjunction with specific embodiments. However, those skilled in the art should understand that the following embodiments are only used to illustrate the present invention and should not be regarded as a limitation to the present invention. The specific conditions not specified in the embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, unless otherwise specified, are all conventional products obtained through commercial channels.

[0024] The diameter of the mullite whiskers is 1 - 2 μm, and the aspect ratio is 20 - 30; the silane coupling agent is KH550 or KH560. The photovoltaic cutting waste is the waste generated during the production of silicon wafers.

[0025] Example 1 A high-strength building ceramic material, comprising 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; The preparation process of the modified mullite whiskers is as follows: (1) Prepare an ethanol aqueous solution by mixing anhydrous ethanol and water at a volume ratio of 4:1. Add the mullite whiskers to the ethanol aqueous solution containing KH550. The mass ratio of the mullite whiskers to KH550 is 1:0.1, and the dosage ratio of the mullite whiskers to the ethanol aqueous solution is 1 g:10 mL. Heat and react at 60 °C for 16 h. Filter, wash, and dry the reaction solution to obtain pretreated mullite whiskers; (2) Prepare an aqueous solution of nickel sulfate with a mass concentration of 5%. Add the pretreated mullite whiskers from step (1) to the aqueous solution of nickel sulfate, and then add triethylamine and sodium thiosulfate. The mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine, and sodium thiosulfate is 1:10:1.5:4. Heat and react at 95 °C for 2.5 h. Then filter, wash, and dry the reaction solution to obtain modified mullite whiskers.

[0026] The preparation process of the filler is as follows: Take graphene and disperse it in water, and then add polyvinyl alcohol and konjac glucomannan. The mass ratio of graphene, polyvinyl alcohol, konjac glucomannan, and water is 1:4:2.5:18. Ultrasonically disperse evenly and spray-dry at 75 °C to obtain the filler.

[0027] The preparation process of the solid waste-based silicon carbide is as follows: Take the photovoltaic cutting waste, grind it and then screen it, and then put it into a 10% hydrofluoric acid solution, stir evenly, let it stand at room temperature for 12 h, and then filter the standing solution. Dry the filtered solid to obtain the solid waste-based silicon carbide.

[0028] The preparation method of the above high-strength building ceramic material includes the following steps: a. Wet ball-mill potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler to obtain a slurry; b. Inject the slurry into a mold, let it stand at room temperature for 28 h; dry and shape it; heat it to 800 °C and keep it warm for 2.5 h; then raise the temperature to 1150 °C at a heating rate of 20 °C / min. After reaching the target temperature, pressurize it to 5 MPa and keep it warm for 1.5 h; thus obtained.

[0029] Example 2 A high-strength building ceramic material, comprising 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; The preparation process of the modified mullite whiskers is as follows: (1) Prepare an ethanol aqueous solution by mixing absolute ethanol and water at a volume ratio of 4:1. Add mullite whiskers to the ethanol aqueous solution containing KH550. The mass ratio of the mullite whiskers to KH550 is 1:0.05, and the dosage ratio of the mullite whiskers to the ethanol aqueous solution is 1 g:10 mL. Heat and react at 55 °C for 18 h. Filter, wash, and dry the reacted solution to obtain pretreated mullite whiskers; (2) Prepare an aqueous solution of nickel sulfate with a mass concentration of 3%. Add the pretreated mullite whiskers obtained in step (1) to the aqueous solution of nickel sulfate, and then add triethylamine and sodium thiosulfate. The mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine, and sodium thiosulfate is 1:6:1:3. Heat and react at 90 °C for 3.5 h. Then filter, wash, and dry the reaction solution to obtain modified mullite whiskers.

[0030] The preparation process of the filler is as follows: Take graphene and disperse it in water, and then add polyvinyl alcohol and konjac glucomannan. The mass ratio of graphene, polyvinyl alcohol, konjac glucomannan, and water is 1:3:2:16. Ultrasonically disperse evenly and spray-dry at 80 °C to obtain the filler.

[0031] The preparation process of the solid waste-based silicon carbide is as follows: Take photovoltaic cutting waste, grind it and then screen it. Put it into a 10% hydrofluoric acid solution, stir evenly, stand at room temperature for 12 h, and then filter the standing solution. Dry the filtered solid to obtain the solid waste-based silicon carbide.

[0032] The preparation method of the above high-strength building ceramic material comprises the following steps: a. Wet ball-mill potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and filler to obtain a slurry; b. Inject the slurry into a mold, stand at room temperature for 28 h; dry and shape; keep warm at 800 °C for 2 h; then raise the temperature to 1150 °C at a heating rate of 20 °C / min. After reaching the target temperature, apply a pressure of 3 MPa and keep warm for 2 h; thus obtained.

[0033] Example 3 A high-strength building ceramic material, comprising 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; The preparation process of the modified mullite whiskers is as follows: (1) Prepare an ethanol aqueous solution by mixing anhydrous ethanol and water at a volume ratio of 4:1. Add mullite whiskers to the ethanol aqueous solution containing KH550. The mass ratio of the mullite whiskers to KH550 is 1:0.15, and the dosage ratio of the mullite whiskers to the ethanol aqueous solution is 1 g:10 mL. Heat and react at 65 °C for 12 h. Filter, wash, and dry the reaction solution to obtain pretreated mullite whiskers. (2) Prepare an aqueous nickel sulfate solution with a mass concentration of 8%. Add the pretreated mullite whiskers from step (1) to the aqueous nickel sulfate solution, and then add triethylamine and sodium thiosulfate. The mass ratio of the pretreated mullite whiskers, nickel sulfate, triethylamine, and sodium thiosulfate is 1:12:2:5. Heat and react at 100 °C for 1.5 h. Then filter, wash, and dry the reaction solution to obtain modified mullite whiskers.

[0034] The preparation process of the filler is as follows: Disperse graphene in water, and then add polyvinyl alcohol and konjac glucomannan. The mass ratio of graphene, polyvinyl alcohol, konjac glucomannan, and water is 1:5:3:20. Ultrasonically disperse evenly and spray-dry at 85 °C to obtain the filler.

[0035] The preparation process of solid waste-based silicon carbide is as follows: Grind photovoltaic cutting waste and sieve it, put it into a 10% hydrofluoric acid solution, stir evenly, stand at room temperature for 12 h, then filter the standing solution, and dry the filtered solid to obtain solid waste-based silicon carbide.

[0036] The preparation method of the above high-strength building ceramic material includes the following steps: a. Wet ball-mill potassium feldspar, kaolin, solid waste-based silicon carbide, talc, modified mullite whiskers, and the filler to obtain a slurry. b. Inject the slurry into a mold, stand at room temperature for 28 h; dry and shape; keep warm at 800 °C for 3 h; then raise the temperature to 1150 °C at a heating rate of 20 °C / min, apply pressure to 6 MPa after reaching the target temperature, and keep warm for 1 h; thus obtained.

[0037] Comparative Example 1 This Comparative Example 1 is basically the same as Example 1, the difference is that the modified mullite whiskers are replaced with mullite whiskers and nickel sulfide (mass ratio 1:4).

[0038] Comparative Example 2 This Comparative Example 2 is basically the same as Example 1, the difference is that the filler is replaced with graphene and konjac glucomannan (mass ratio 1:2.5).

[0039] Figure 1This is the SEM image of the modified mullite whiskers of the present invention. It can be observed that the diameters of the modified mullite whiskers are relatively uniform, and a relatively dense nickel sulfide layer is evenly deposited on the surface, indicating that nickel sulfide has been successfully coated on the surface of the mullite whiskers.

[0040] Test Example 1 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 carried out: (1) Thermal conductivity efficiency test: The hot wire method was used to test the thermal conductivity of the samples in each group of Examples 1-3 and Comparative Examples 1-2. 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.

[0041] (2) Flexural strength test: The three-point bending method was used to test the flexural strength of the samples in each group of Examples 1-3 and Comparative Examples 1-2 on a universal testing machine. The experimental results are shown in Table 1.

[0042] Table 1 The higher the thermal conductivity, the stronger the heat conduction ability of the material, that is, the faster the rate of heat transfer inside the material. From the data in Table 1, it can be seen that the thermal conductivity and flexural strength of the ceramic tiles in Examples 1-3 of the present invention are higher than those in Comparative Examples 1 and 2, indicating that the ceramic tiles of the present invention have good heat conduction ability and excellent mechanical strength, and are suitable for ordinary home decoration and high thermal conductivity floor heating ceramic tiles.

[0043] Compared with Example 1, in Comparative Example 1, the modified mullite whiskers were replaced with mullite whiskers and nickel sulfide; in Comparative Example 2, the filler was replaced with graphene and konjac glucomannan, and the thermal conductivity and flexural strength of the ceramic materials became worse, 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 heat conduction, help to increase the room temperature and keep warm, which is of great significance for improving the comprehensive performance of ceramic tiles.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. The basic principles and main features of the present invention have been described with specific implementation schemes above. On the basis of the present invention, some modifications or replacements can be made, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the present invention claimed.

Claims

1. A high-strength building ceramic material, characterized in that, It comprises the following raw materials in parts by weight: 20 - 30 parts of potassium feldspar, 15 - 23 parts of kaolin, 37 - 45 parts of 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) Add mullite whiskers to an ethanol aqueous solution containing a silane coupling agent, and heat for reaction to obtain pretreated mullite whiskers; (2) Add the pretreated mullite whiskers obtained in step (1) to an aqueous solution of nickel sulfate, then add triethylamine and sodium thiosulfate, and heat for reaction to obtain modified mullite whiskers.

2. The high-strength building ceramic material according to claim 1, characterized in that, In step (1), the dosage ratio of the mullite whiskers, silane coupling agent, and ethanol aqueous solution is 1 g: 0.05 - 0.15 g: 10 mL; 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 - 18 h.

3. The high-strength building ceramic material according to claim 1, wherein, The diameter of the mullite whiskers 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 h.

5. The high-strength building ceramic material according to claim 1, characterized in that, The preparation process of the filler is as follows: Take graphene and disperse it in water, then add polyvinyl alcohol and konjac glucomannan, and ultrasonically disperse evenly, and spray dry to obtain the filler.

6. The high-strength building ceramic material according to claim 5, characterized in that, The mass ratio of the graphene, polyvinyl alcohol, konjac glucomannan, and water is 1: (3 - 5): (2 - 3): (16 - 20).

7. The high-strength building ceramic material according to claim 1, wherein, The preparation process of the waste-based silicon carbide is as follows: Grind the photovoltaic cutting waste, sieve it, pickle it, and dry it to obtain the waste-based silicon carbide.

8. The high-strength building ceramic material according to claim 7, wherein, The solvent used for pickling is a hydrofluoric acid solution with a mass concentration of 6 - 10%; the pickling time is 10 - 12 h.

9. The preparation method of a high-strength building ceramic material according to any one of claims 1-8, characterized in that, It includes the following steps: a. Wet ball mill potassium feldspar, kaolin, waste-based silicon carbide, talc, modified mullite whiskers, and filler, remove iron and sieve to obtain a slurry; b. Inject the slurry into a mold, let it stand at room temperature for 28 h; dry and shape it; then carry out gradient sintering; thus obtained.

10. The preparation method of a high-strength building ceramic material according to claim 9, characterized in that, The gradient sintering is to first keep the temperature at 800 °C for 2 - 3 h; then raise the temperature to 1150 °C, with a heating rate of 20 °C / min. After reaching the target temperature, pressurize to 2 - 6 MPa and keep the temperature for 1 - 2 h.

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