Graphene calcium silicate plate and preparation method and use method thereof

Abstract

This invention provides a graphene calcium silicate board, its preparation method, and its usage method. The graphene calcium silicate board is made of siliceous materials, calcareous materials, fibers, and graphene; the graphene content in the graphene calcium silicate board is 0.1-0.5‰ by mass. In this invention, by adding a specific amount of graphene to the graphene calcium silicate board and ensuring its uniform distribution, the board achieves a low freezing temperature, can melt thick ice layers in a short time, and has low energy consumption. It is particularly suitable for exterior walls in northern and extremely cold regions, and has a long service life.

Description

Technical Field

[0001] This invention belongs to the technical field of calcium silicate board materials, specifically relating to a graphene calcium silicate board and its preparation and usage methods. Background Technology

[0002] Calcium silicate board is a type of board made by mixing siliceous materials, calcareous materials, and plant fibers in a certain proportion, and then producing it using a controlled process involving slurry casting or sheet forming, followed by high-pressure oxygen steaming. Calcium silicate board has advantages such as Class A fire resistance, high strength, and low density; therefore, it is increasingly being used in exterior wall construction, replacing marble or ceramic slabs. However, because calcium silicate board has a water absorption rate greater than 20%, in northern regions, the accumulation of snow and condensation on the walls during winter causes the board to absorb water and freeze-thaw, leading to damage. This damage can range from minor delamination to severe powdering, with the surface finish peeling off, making repairs very difficult.

[0003] In existing technologies, waterproofing agents are typically applied to the surface of the boards. These waterproofing agents mainly fall into two categories: oil-based waterproofing agents, which are generally organosilane compounds containing harmful substances such as toluene and xylene, and are diluted with butyl diformate or ketone diluents. These agents have a strong odor, making them difficult to handle in the workshop. The second category is silicate-based waterproofing agents. While these are environmentally friendly, they leave white spots on the boards after application, and the water absorption does not significantly decrease after immersion in water, resulting in poor waterproofing. Existing technologies disclose the addition of waterproofing agents during production for overall waterproofing. However, since the slurry concentration during calcium silicate board production is around 10%, which is mostly water, the added waterproofing agent is easily washed away with the water, making it difficult to improve the production process.

[0004] Therefore, developing a graphene-calcium silicate board that does not freeze at low temperatures, can melt a thick ice layer in a short time, and has a feasible production process is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a graphene calcium silicate board, its preparation method, and its usage method. By adding a specific amount of graphene to the calcium silicate board, and ensuring the graphene is uniformly distributed throughout the board, the calcium silicate board exhibits a low freezing temperature, can melt thick ice layers in a short time, and has low energy consumption. It is particularly suitable for exterior walls in northern and extremely cold regions, and has a long service life.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a graphene calcium silicate board, wherein the material of the graphene calcium silicate board includes siliceous materials, calcareous materials, fibers and graphene; the mass content of graphene in the graphene calcium silicate board is 0.1 to 0.5‰.

[0008] Graphene possesses excellent strength, flexibility, and electrical and thermal conductivity. It can generate heat when energized. When electrodes are connected to both ends of a graphene electrothermal film and electricity is applied, carbon molecules in the film generate phonons, ions, and electrons within the resistance. Heat is generated through friction and collisions between these carbon molecule clusters (Brownian motion). This heat can be uniformly radiated in a planar manner by controlling far-infrared radiation. After being energized, graphene achieves an effective total electrothermal energy conversion rate of over 99%, and its unique superconductivity ensures stable heating performance. In this invention, by adding a specific amount of graphene to a calcium silicate board, which is uniformly distributed within the board and combined with other components, the resulting calcium silicate board exhibits high strength, is non-deformable, and has a low freezing point. It can melt thick ice deposits quickly with low energy consumption, resulting in a long service life, making it particularly suitable for exterior wall materials in extremely cold regions.

[0009] Preferably, the graphene content in the graphene calcium silicate board is 0.1-0.5‰ by mass, for example, it can be 0.12‰, 0.14‰, 0.16‰, 0.18‰, 0.2‰, 0.22‰, 0.24‰, 0.26‰, 0.28‰, 0.3‰, 0.32‰, 0.34‰, 0.36‰, 0.38‰, 0.4‰, 0.42‰, 0.44‰, 0.46‰, 0.48‰, etc.

[0010] Preferably, the mass ratio of the siliceous material, the calcareous material, and the fiber is (500-600):(400-500):(7-8); wherein, the specific values ​​of (500-600) can be, for example, 510, 520, 530, 540, 550, 560, 570, 580, 590, etc.; the specific values ​​of (400-500) can be, for example, 410, 420, 430, 440, 450, 460, 470, 480, 490, etc.; and the specific values ​​of (7-8) can be, for example, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, etc.

[0011] Preferably, the siliceous material includes at least one of quartz sand, fly ash, or diatomaceous earth.

[0012] Preferably, the calcareous material includes at least one of cement, quicklime, or hydrated lime.

[0013] Preferably, the fiber comprises wood fiber.

[0014] In a second aspect, the present invention provides a method for preparing a graphene calcium silicate board according to the first aspect, the method comprising the following steps:

[0015] (1) A slurry is obtained by mixing siliceous materials, calcareous materials and fibers with a solvent; the slurry is then filtered through a screen wheel to obtain a slab.

[0016] (2) After vacuum dehydration of the slab obtained in step (1), graphene is evenly sprinkled on the surface of the slab, wound into shape, and steam-cured to obtain the graphene calcium silicate board.

[0017] Preferably, the mixing temperature in step (1) is 5 to 35°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, etc.; the mixing rate is 100 to 250 rpm, for example, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, etc.

[0018] Preferably, the solid content of the slurry is 6-10%, for example, it can be 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

[0019] Preferably, the thickness of the slab in step (1) is 0.5 to 1.5 mm, for example, it can be 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, etc.

[0020] Preferably, step (2) further includes conveying the slab onto a blanket before vacuum dehydration.

[0021] Preferably, the conveying speed of the blanket is 30 to 50 meters per minute, for example, it can be 32 meters per minute, 34 meters per minute, 36 meters per minute, 38 meters per minute, 40 meters per minute, 42 meters per minute, 44 meters per minute, 46 meters per minute, 48 meters per minute, etc.

[0022] Preferably, the device for uniformly spreading graphene on the surface of the slab includes a graphene vibrating screen.

[0023] Preferably, the vibration frequency of the graphene vibrating screen is 50 to 100 times / min, for example, it can be 55 times / min, 60 times / min, 65 times / min, 70 times / min, 75 times / min, 80 times / min, 85 times / min, 90 times / min, 95 times / min, etc.

[0024] Preferably, the winding forming equipment includes a forming cylinder.

[0025] Preferably, the molding process further includes cutting, stacking, and laminating steps.

[0026] Preferably, the lamination time is 15 to 25 minutes, for example, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, etc.

[0027] In this invention, the formed graphene wet preform is cut into fixed-size stacks, stainless steel pads are added between each layer, and then lamination is performed.

[0028] Preferably, the autoclaving process includes a pre-curing step.

[0029] Preferably, the pre-curing temperature is 40-60℃, for example, 45℃, 50℃, 55℃, etc.

[0030] Preferably, the pre-curing time is 4 to 5 hours, for example, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, etc.

[0031] Preferably, the temperature for autoclaving is 180–190°C, for example, 182°C, 184°C, 186°C, 188°C, etc.

[0032] Preferably, the autoclaving time is 8 to 16 hours, for example, 10 hours, 12 hours, 14 hours, etc.

[0033] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0034] (1) The siliceous material, calcareous material and fiber are mixed with solvent at 5-35°C and 100-250 rpm to obtain a slurry with a solid content of 6-10%; the slurry is filtered through a screen wheel to obtain a slab.

[0035] (2) The slab obtained in step (1) is transported to a blanket, and after vacuum dehydration, graphene is evenly sprinkled on the surface of the slab using a graphene vibrating screen with a vibration frequency of 50 to 100 times / min. The slab is wound and shaped, pre-cured at 40 to 60°C for 4 to 5 hours, and then steam-cured at 180 to 190°C for 8 to 16 hours to obtain the graphene calcium silicate board.

[0036] This invention employs a specific preparation method that enables graphene to be uniformly dispersed in calcium silicate boards, thereby further improving the cold resistance of the calcium silicate boards.

[0037] In this invention, at high temperatures, the Ca in cement... + It reacts with SiO2 in quartz sand to form hydrated CaSiO3, also known as tobermorite, with the molecular formula Ca5Si6O. 16 (OH)2·4H2O C5S6H5, graphene is stable and does not participate in the reaction, while tobermorite has high strength and does not deform, making it suitable for use on exterior walls.

[0038] Thirdly, the present invention provides a method of using a graphene calcium silicate board as described in the first aspect, wherein the graphene calcium silicate board is used under energized conditions.

[0039] Preferably, the voltage applied is 6 to 9V, for example, 6.5V, 7V, 7.5V, 8V, 8.5V, etc.

[0040] In this invention, the graphene calcium silicate board is used in the exterior walls of buildings in extremely cold regions.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] The graphene calcium silicate board provided by this invention, by adding a specific amount of graphene and ensuring that the graphene is evenly distributed in the calcium silicate board, results in a low freezing temperature. It can melt 3-5cm thick ice with an applied voltage of 6-9V, has low energy consumption, and its cold resistance will not deteriorate over time. It is especially suitable for exterior walls in northern and extremely cold regions and has a long service life. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the power-on installation of the graphene calcium silicate board provided by the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] Example 1

[0047] This embodiment provides a graphene calcium silicate board, the materials of which include quartz sand, cement, wood fiber and graphene; the mass ratio of quartz sand, cement and wood fiber is 550:450:7.5, and the mass content of graphene in the graphene calcium silicate board is 0.3‰.

[0048] This embodiment provides a method for preparing a graphene calcium silicate board, specifically including the following steps:

[0049] (1) According to the formula, quartz sand, cement and wood fiber are mixed with water at 25°C and 200 rpm to obtain a slurry with a solid content of 6%; the slurry is filtered through a mesh wheel to obtain a slab with a thickness of 1 mm.

[0050] (2) The slab obtained in step (1) is transferred to a blanket (the blanket conveying speed is 40 m / min) by rotating a mesh wheel. After vacuum dehydration, graphene is evenly sprinkled on the surface of the slab using a graphene vibrating screen with a vibration frequency of 70 times / min. The slab is wound into a set thickness by a forming cylinder. Once a certain thickness is reached, it is automatically cut into wet slabs. The wet slabs are cut into fixed sizes and stacked. Stainless steel pads are added between each layer. The slabs are then pressed on a press for 20 minutes, pre-cured at 50°C for 5 hours, and then steam-cured at 180°C for 10 hours to obtain the graphene calcium silicate board.

[0051] Example 2

[0052] This embodiment provides a graphene calcium silicate board, the materials of which include quartz sand, cement, wood fiber and graphene; the mass ratio of quartz sand, cement and wood fiber is 550:450:7.5, and the mass content of graphene in the graphene calcium silicate board is 0.1‰.

[0053] This embodiment provides a method for preparing a graphene calcium silicate board, specifically including the following steps:

[0054] (1) According to the formula, quartz sand, cement and wood fiber are mixed with water at 30°C and 100 rpm to obtain a slurry with a solid content of 6%; the slurry is filtered through a mesh wheel to obtain a slab with a thickness of 1 mm.

[0055] (2) The slab obtained in step (1) is transferred to a blanket (the blanket conveying speed is 30 m / min) by rotating a mesh wheel. After vacuum dehydration, graphene is evenly sprinkled on the surface of the slab using a graphene vibrating screen with a vibration frequency of 60 times / min. The slab is wound into a set thickness by a forming cylinder. Once a certain thickness is reached, it is automatically cut into wet slabs. The wet slabs are cut into fixed sizes and stacked. Stainless steel pads are added between each layer. The slabs are then pressed on a press for 20 minutes, pre-cured at 50°C for 4 hours, and then steam-cured at 180°C for 12 hours to obtain the graphene calcium silicate board.

[0056] Example 3

[0057] This embodiment provides a graphene calcium silicate board, the materials of which include quartz sand, cement, wood fiber and graphene; the mass ratio of quartz sand, cement and wood fiber is 550:450:7.5, and the mass content of graphene in the graphene calcium silicate board is 0.5‰.

[0058] This embodiment provides a method for preparing a graphene calcium silicate board, specifically including the following steps:

[0059] (1) According to the formula, quartz sand, cement and wood fiber are mixed with water at 15°C and 250 rpm to obtain a slurry with a solid content of 6%; the slurry is filtered through a mesh wheel to obtain a slab with a thickness of 1 mm.

[0060] (2) The slab obtained in step (1) is transferred to a blanket (the blanket conveying speed is 50 m / min) by rotating a mesh wheel. After vacuum dehydration, graphene is evenly sprinkled on the surface of the slab using a graphene vibrating screen with a vibration frequency of 80 times / min. The slab is wound into a set thickness by a forming cylinder. Once a certain thickness is reached, it is automatically cut into wet slabs. The wet slabs are cut into fixed sizes and stacked. Stainless steel pads are added between each layer. The slabs are then pressed on a press for 20 minutes, pre-cured at 50°C for 5 hours, and then steam-cured at 190°C for 8 hours to obtain the graphene calcium silicate board.

[0061] Example 4

[0062] This embodiment provides a graphene calcium silicate board, the materials of which include quartz sand, cement, wood fiber and graphene; the mass ratio of quartz sand, cement and wood fiber is 520:480:7.2, and the mass content of graphene in the graphene calcium silicate board is 0.3‰.

[0063] This embodiment provides a method for preparing a graphene calcium silicate board, and the specific steps are the same as in Embodiment 1.

[0064] Example 5

[0065] This embodiment provides a graphene calcium silicate board, the materials of which include quartz sand, cement, wood fiber and graphene; the mass ratio of quartz sand, cement and wood fiber is 580:420:7.8, and the mass content of graphene in the graphene calcium silicate board is 0.4‰.

[0066] This embodiment provides a method for preparing a graphene calcium silicate board, and the specific steps are the same as in Embodiment 1.

[0067] Example 6

[0068] This embodiment provides a graphene calcium silicate board, which differs from Embodiment 1 only in that the total amount of quartz sand, cement and wood fiber remains unchanged, the mass ratio is 600:400:10, and the mass content of graphene in the graphene calcium silicate board is 0.3‰.

[0069] This embodiment provides a method for preparing a graphene calcium silicate board, and the specific steps are the same as in Embodiment 1.

[0070] Example 7

[0071] This embodiment provides a graphene calcium silicate board, which differs from Embodiment 1 only in that the vibration frequency of the graphene vibrating screen in the preparation method of the graphene calcium silicate board is 30 times / min, while the other materials, dosages and step parameters are the same as in Embodiment 1.

[0072] Example 8

[0073] This embodiment provides a graphene calcium silicate board, which differs from Embodiment 1 only in that the vibration frequency of the graphene vibrating screen in the preparation method of the graphene calcium silicate board is 150 times / min, while the other materials, dosages and step parameters are the same as in Embodiment 1.

[0074] Example 9

[0075] This embodiment provides a graphene calcium silicate board, which differs from Embodiment 1 only in that the slurry mixed in step (1) of the preparation method of the graphene calcium silicate board also includes graphene, and the step (2) does not use a graphene vibrating screen with a vibration frequency of 70 times / min to evenly sprinkle graphene on the surface of the board blank. Other materials, dosages and step parameters are the same as in Embodiment 1.

[0076] Comparative Example 1

[0077] This comparative example provides a graphene calcium silicate board, which differs from Example 1 only in that the graphene content in the graphene calcium silicate board is 1‰ by mass, while the other materials, amounts, and step parameters are the same as in Example 1.

[0078] Performance testing

[0079] The graphene calcium silicate boards provided in the above embodiments and comparative examples were connected to a power source. Under voltage conditions of 6V and 9V, the time required for the calcium silicate board to melt a 3cm thick ice layer and the temperature at which ice began to form on the surface of the calcium silicate board were recorded. A schematic diagram of the graphene calcium silicate board connected to a power source is shown below. Figure 1 As shown, each wall is connected to a 6V or 9V low-voltage power supply, and the other side can be directly connected to the ground. The 6V or 9V power supply can be directly powered and stored by solar energy, consuming little energy.

[0080] The specific test results are shown in Table 1:

[0081] Table 1

[0082]

[0083]

[0084] As shown in the table above, the graphene calcium silicate board provided by this invention, by adding a specific amount of graphene and ensuring that the graphene is evenly distributed in the calcium silicate board, results in a low freezing temperature of -5 to -26°C. With an applied voltage of 6 to 9V, it can melt 3 to 5 cm thick ice within 3 to 30 minutes. It has low energy consumption and its cold resistance does not deteriorate over time, making it particularly suitable for exterior walls in northern and extremely cold regions, with a long service life.

[0085] Examples 1 and 6-9, which are not specific material ratios or preparation processes, show that the calcium silicate boards have poor performance.

[0086] As can be seen from Example 1 and Comparative Example 1, increasing the amount of graphene has little effect on improving the cold resistance of calcium silicate board, and the cost is high.

[0087] In summary, the graphene-calcium silicate board provided by this invention does not freeze or get damaged by freezing when used at low temperatures. The graphene content in the board is 0.3‰, and it uses a 6V power supply, offering the best cost-effectiveness. This solves the problems of high raw material costs, easy deformation, and unsatisfactory energy-saving effects associated with using metal sheets to increase cold resistance in existing technologies. The surface of the board can be coated with various decorative paints for use in building exterior walls or tunnels, replacing stone. It has a long service life and is suitable as an exterior wall material in extremely cold regions.

[0088] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A graphene-calcium silicate board, characterized in that, The graphene calcium silicate board is made of siliceous materials, calcareous materials, fibers, and graphene. The graphene content in the graphene-calcium silicate board is 0.1-0.5‰ by mass. The graphene-calcium silicate board is prepared by the following method, which includes the following steps: (1) Mix siliceous materials, calcareous materials and fibers with a solvent to obtain a slurry; filter the slurry through a screen wheel to obtain a slab; (2) After vacuum dehydration of the slab obtained in step (1), graphene is evenly sprinkled on the surface of the slab, wound into shape, and steam-cured to obtain the graphene calcium silicate board.

2. The graphene-calcium silicate board according to claim 1, characterized in that, The mass ratio of the siliceous material, the calcareous material and the fiber is (500~600):(400~500):(7~8).

3. The graphene-calcium silicate board according to claim 1, characterized in that, The siliceous material includes at least one of quartz sand, fly ash, or diatomaceous earth.

4. The graphene calcium silicate board according to claim 1, characterized in that, The calcareous material includes at least one of cement, quicklime, or hydrated lime.

5. The graphene-calcium silicate board according to claim 1, characterized in that, The fibers include wood fibers.

6. A method for preparing a graphene-calcium silicate board according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Mix siliceous materials, calcareous materials and fibers with a solvent to obtain a slurry; filter the slurry through a screen wheel to obtain a slab; (2) After vacuum dehydration of the slab obtained in step (1), graphene is evenly sprinkled on the surface of the slab, wound into shape, and steam-cured to obtain the graphene calcium silicate board.

7. The preparation method according to claim 6, characterized in that, The mixing temperature in step (1) is 5~35℃ and the mixing rate is 100~250 rpm.

8. The preparation method according to claim 6, characterized in that, The solid content of the slurry is 6-10%.

9. The preparation method according to claim 6, characterized in that, The thickness of the slab in step (1) is 0.5~1.5mm.

10. The preparation method according to claim 6, characterized in that, Step (2) before vacuum dehydration also includes conveying the slab onto a blanket.

11. The preparation method according to claim 10, characterized in that, The blanket is conveyed at a speed of 30-50 meters per minute.

12. The preparation method according to claim 6, characterized in that, The device for uniformly spreading graphene on the surface of the slab includes a graphene vibrating screen.

13. The preparation method according to claim 12, characterized in that, The vibration frequency of the graphene vibrating screen is 50~100 times / min.

14. The preparation method according to claim 6, characterized in that, The winding forming equipment includes a forming cylinder.

15. The preparation method according to claim 6, characterized in that, The molding process also includes cutting, stacking, and laminating steps.

16. The preparation method according to claim 15, characterized in that, The lamination time is 15-25 minutes.

17. The preparation method according to claim 6, characterized in that, The autoclaving process also includes a pre-curing step.

18. The preparation method according to claim 17, characterized in that, The pre-curing temperature is 40~60℃.

19. The preparation method according to claim 17, characterized in that, The pre-conditioning time is 4-5 hours.

20. The preparation method according to claim 6, characterized in that, The temperature for autoclaving is 180~190℃.

21. The preparation method according to claim 6, characterized in that, The autoclaving time is 8-16 hours.

22. The preparation method according to claim 6, characterized in that, The preparation method includes the following steps: (1) The siliceous material, calcareous material and fiber are mixed with solvent at 5~35℃ and 100~250 rpm to obtain a slurry with a solid content of 6~10%; the slurry is filtered through a screen wheel to obtain a slab. (2) The slab obtained in step (1) is transported to a blanket, and after vacuum dehydration, graphene is evenly sprinkled on the surface of the slab using a graphene vibrating screen with a vibration frequency of 50~100 times / min. The slab is wound and shaped, pre-cured at 40~60℃ for 4~5 h, and then steam-cured at 180~190℃ for 8~16 h to obtain the graphene calcium silicate board.

23. A method of using a graphene calcium silicate board as described in any one of claims 1-5, characterized in that, The graphene calcium silicate board is used under energized conditions.

24. The method of use according to claim 23, characterized in that, The voltage applied is 6~9 V.

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