Preparation method of high-temperature-resistant ceramic fiber insulation board

Abstract

The invention discloses a preparation method of a high-temperature-resistant ceramic fiber insulation board, which comprises the following steps: injecting a first suspension corresponding to ceramic fibers into an insulation board model, and carrying out vacuum dehydration and compression molding on the first suspension in the insulation board model to obtain a first wet blank; the first wet blank is placed in a first drying chamber, the first drying chamber is controlled to preliminarily heat the first wet blank, a temperature field corresponding to the surface of the first wet blank is captured through an infrared thermal imager, and the moisture distribution difference of all areas on the first wet blank is obtained; further obtaining the humidification amount required by each area and applying the corresponding humidification amount, so that the moisture of each area on the first wet blank is uniformly distributed; a first drying chamber is controlled to evenly heat the first wet blank at intervals, and a heat preservation plate rough blank is obtained; and transferring the insulation board rough blank to a sintering furnace for sintering to obtain the high-temperature-resistant ceramic fiber insulation board. The drying quality of the ceramic fiber insulation board wet blank can be improved, so that the quality of the ceramic fiber insulation board finished product is improved.

Description

Technical Field

[0001] The present invention relates to the field of ceramic fiber insulation boards, and particularly to a preparation method for high-temperature resistant ceramic fiber insulation boards. Background Art

[0002] Due to high thermal stability and low thermal conductivity, ceramic fiber insulation boards are widely used in various high-temperature occasions, including belt sintering machines, heat treatment furnaces, and aluminum electrolytic cells in the metallurgical industry, firing kilns for ceramics and building materials products, and various petrochemical industrial heating furnaces.

[0003] Drying is a key step in the preparation of ceramic fiber insulation boards, aiming to gradually remove the moisture in the wet blank and avoid material cracking and structural damage caused by rapid dehydration. However, due to the forming process, slurry characteristics, and dehydration process of the wet blank of the ceramic fiber insulation board, the moisture distribution in each area of the wet blank of the ceramic fiber insulation board is uneven, resulting in local shrinkage differences during the drying process, that is, high-moisture area: when drying, the moisture evaporates violently, the volume shrinks greatly, and a shrinkage stress concentration area is formed; low-moisture area: the shrinkage degree is small, and shear stress is formed with the high-moisture area, leading to the initiation of microcracks. Therefore, the uneven initial moisture distribution of the wet blank of the ceramic fiber insulation board is not only the starting point problem of the drying process, but also the "domino" source that causes subsequent cracking, deformation, and performance fluctuations. Summary of the Invention

[0004] In view of the above-mentioned partial defects of the prior art, the technical problem to be solved by the present invention is to provide a preparation method for high-temperature resistant ceramic fiber insulation boards, aiming to improve the drying quality of the wet blank of the ceramic fiber insulation board, thereby improving the finished product quality of the ceramic fiber insulation board.

[0005] To achieve the above object, the present invention discloses a preparation method for high-temperature resistant ceramic fiber insulation boards, and the method includes:

[0006] Step S1: Mix ceramic fiber and deionized water in a first preset ratio, and add a first amount of dispersant, and obtain a first suspension through high-speed shear stirring;

[0007] Step S2: Inject the first suspension into a insulation board mold, and perform vacuum dehydration and pressing on the first suspension in the insulation board mold to obtain a first wet blank with a water content less than the first preset water content;

[0008] Step S3: Place the first wet blank in a first drying chamber, control the first drying chamber to initially heat the first wet blank at a first temperature, capture the temperature field corresponding to the surface of the first wet blank through an infrared thermal imager, and obtain the moisture distribution difference in each area of the first wet blank; wherein, the evaporation of moisture absorbs heat, and the temperature rise degrees of areas with different moisture contents are different;

[0009] Step S4: Obtain the humidification amounts required for each area on the first green blank according to the moisture distribution differences in each area on the first green blank; control the humidification device to apply the corresponding humidification amounts to each area on the first green blank, so as to make the moisture distribution in each area on the first green blank uniform;

[0010] Step S5: Control the first drying chamber to uniformly heat the first green blank intermittently at a second temperature, so that the moisture inside the first green blank diffuses to the surface during the period without heat, and obtain a rough blank of the insulating board; wherein, the second temperature is greater than the first temperature;

[0011] Step S6: Transfer the rough blank of the insulating board to a sintering furnace for sintering to obtain a high-temperature resistant ceramic fiber insulating board.

[0012] Optionally, a plurality of heaters are arranged in the first drying chamber, the heaters are evenly distributed to uniformly heat the first green blank, an infrared thermal imager is arranged at the top of the first drying chamber, the infrared thermal imager has different imaging colors for objects at different temperatures, and a humidification device is further arranged in the first drying chamber, and the humidification device is used to perform corresponding humidification on the first green blank.

[0013] Optionally, step S3 includes:

[0014] Step S301: Place the first green blank into the first drying chamber, and control the first drying chamber to perform preliminary heating on the first green blank at a first temperature;

[0015] Step S302: After the preliminary heating for a first duration, stop heating, and control the infrared thermal imager to collect and capture the temperature field on the surface of the first green blank;

[0016] Step S303: Obtain the moisture distribution in each area on the first green blank according to the color distribution corresponding to the temperature field, and further obtain the moisture distribution differences in each area on the first green blank.

[0017] Optionally, step S4 includes:

[0018] Step S401: Obtain the area with the highest moisture content according to the moisture distribution differences in each area on the first green blank;

[0019] Step S402: Determine the difference in moisture content between other areas and the area with the highest moisture content as the corresponding humidification amount;

[0020] Step S403: Control the humidifying device to apply the corresponding humidification amount to each area of the first wet blank, so as to make the moisture distribution in each area of the first wet blank uniform; wherein, when there is one humidifying device, control the humidifying device to move for humidifying each area, and when there are multiple humidifying devices, control the humidifying devices to humidify the corresponding areas.

[0021] Optionally, the ceramic fiber composition in the step S1 includes: alumina, silica and zirconia; wherein, alumina and silica are the main components, and the zirconia is used to improve the temperature resistance of the ceramic fiber.

[0022] Optionally, the heating method in the step S5 is microwave heating, and the microwave heating makes the internal temperature of the first wet blank higher than the surface temperature, so as to ensure that the internal and external evaporation efficiencies are consistent.

[0023] Optionally, the step S5 further includes:

[0024] Control the first drying chamber to perform three-stage gradient heating on the first wet blank in sequence at a third temperature, a fourth temperature and a fifth temperature; wherein, the fifth temperature is greater than the fourth temperature, and the fourth temperature is greater than the third temperature.

[0025] Optionally, the step S6 includes:

[0026] Step S601: Transfer the rough blank of the heat-insulating board to the sintering furnace, and control the sintering furnace to heat up to 370 °C to remove the organic matter inside the rough blank of the heat-insulating board;

[0027] Step S602: In a reducing or inert atmosphere, control the sintering furnace to heat up to 1000 °C for sintering; then control the sintering furnace to cool down to 800 °C to enhance the crystallinity of the rough blank of the heat-insulating board and obtain the high-temperature resistant ceramic fiber heat-insulating board.

[0028] Optionally, after the step S6, the method further includes:

[0029] Cut and polish the high-temperature resistant ceramic fiber heat-insulating board.

[0030] Advantages of the present invention: 1. During drying, the present invention collects the moisture content in each area of the wet blank of the ceramic fiber heat-insulating board, and performs humidity compensation on each area of the wet blank of the ceramic fiber heat-insulating board according to the difference in moisture distribution, so as to make the moisture distribution in each area of the wet blank of the ceramic fiber heat-insulating board uniform. In the above manner, the present invention effectively avoids the local shrinkage difference caused by uneven moisture distribution during the drying process, which reduces the quality of the finished ceramic fiber heat-insulating board. 2. The present invention dries the wet blank of the ceramic fiber heat-insulating board by intermittent and uniform heating, so that the moisture inside the wet blank of the ceramic fiber heat-insulating board diffuses to the surface during the period without heat, which can effectively avoid the surface moisture of the wet blank of the ceramic fiber heat-insulating board evaporating faster than the internal moisture migration speed, resulting in uneven internal and external shrinkage and stress generation. 3. By designing the structure of the drying chamber, the present invention enables it to have the functions of collecting moisture distribution, drying, and humidifying, reducing redundant equipment and processes. 4. The humidification of the present invention is based on the area with the highest water content, which can ensure uniform humidification in each area.

[0031] In summary, the present invention can improve the drying quality of the wet blank of the ceramic fiber heat-insulating board, avoid problems such as cracking and stress concentration, and thus improve the quality of the finished ceramic fiber heat-insulating board. Brief Description of the Drawings

[0032] Figure 1 It is a schematic flow chart of a method for preparing a high-temperature resistant ceramic fiber heat-insulating board provided by a specific embodiment of the present invention. Detailed Embodiments

[0033] The present invention discloses a method for preparing a high-temperature resistant ceramic fiber heat-insulating board. Those skilled in the art can draw on the content of this article and appropriately improve the technical details to implement it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments. Relevant personnel can obviously make changes or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0034] After research by the applicant, it is found that: existing drying technologies often only consider the problem that "when the wet blank of ceramic fiber insulation board is dried, the surface moisture evaporates faster than the internal moisture migration speed, resulting in uneven shrinkage inside and outside, generating stress, and thus causing the ceramic fiber insulation board to crack". Therefore, existing technologies often make improvements around this problem. However, little consideration is given to the problem that the moisture distribution on each area of the wet blank of ceramic fiber insulation board is uneven due to the forming process, slurry characteristics and dehydration process. This problem leads to local shrinkage differences during the drying process, that is, high moisture area: when drying, the moisture evaporates violently, the volume shrinks greatly, forming a shrinkage stress concentration area; low moisture area: the shrinkage degree is small, and shear stress is formed with the high moisture area, resulting in the initiation of microcracks. Therefore, the uneven initial moisture distribution of the wet blank of ceramic fiber insulation board is not only the starting point problem of the drying process, but also the "domino" source that causes subsequent cracking, deformation and performance fluctuations.

[0035] Therefore, the embodiment of the present invention provides a preparation method of a high-temperature resistant ceramic fiber insulation board, as Figure 1 shown, the method includes:

[0036] Step S1: Mix ceramic fiber and deionized water according to a first preset ratio, and add a first amount of dispersant, and obtain a first suspension through high-speed shear stirring.

[0037] It should be noted that high-speed shearing can cut the ceramic fiber into particles of corresponding size for mixing into the suspension. High-speed shear stirring can be carried out by using a high-speed shearer.

[0038] In this specific embodiment, the ceramic fiber components in step S1 include: alumina, silica and zirconia; among them, alumina and silica are the main components, and zirconia is used to improve the temperature resistance of the ceramic fiber.

[0039] Specifically, the specific components of the ceramic fiber include: Al2O3 (35-55%), SiO2 (45-65%), zirconia (10-15%).

[0040] In a specific embodiment, step S1 is specifically:

[0041] Mix the fiber and deionized water in a ratio of 1:10, add 0.5% dispersant, and perform high-speed shearing (2000 rpm, 30 min) to form a uniform suspension.

[0042] Step S2: Inject the first suspension into the insulation board mold, and perform vacuum dehydration and pressing on the first suspension in the insulation board mold to obtain a first wet blank with a moisture content less than the first preset moisture content.

[0043] In this specific embodiment, the pressing and forming includes: cold isostatic pressing (100 - 200 MPa) or hot pressing (200 - 300 °C, 10 - 20 MPa).

[0044] In this specific embodiment, the vacuum degree of vacuum dehydration is -0.08 Mpa, and the first preset moisture content is 40%.

[0045] Step S3: Place the first green compact into the first drying chamber, control the first drying chamber to preliminarily heat the first green compact at the first temperature, capture the corresponding temperature field on the surface of the first green compact through an infrared thermal imager, and obtain the moisture distribution difference in each area of the first green compact.

[0046] Among them, water evaporation absorbs heat, and the temperature rise degrees of areas with different water contents are different.

[0047] It should be noted that because the water content in each area of the first green compact is different, when absorbing the same amount of heat, the temperature increase is different. Therefore, after preliminary heating, there will be a temperature distribution difference in each area of the first green compact, and the temperature distribution difference corresponds to the moisture distribution difference. Among them, the area with a lower temperature has a higher water content.

[0048] In this specific embodiment, each area of the present invention is a uniformly divided area.

[0049] In this specific embodiment, step S3 includes:

[0050] Step S301: Place the first green compact into the first drying chamber, control the first drying chamber to preliminarily heat the first green compact at the first temperature;

[0051] Step S302: After the preliminary heating for the first duration, stop heating, and control the infrared thermal imager to collect and capture the temperature field on the surface of the first green compact;

[0052] Step S303: According to the color distribution corresponding to the temperature field, obtain the moisture distribution in each area of the first green compact, and then obtain the moisture distribution difference in each area of the first green compact.

[0053] It should be noted that a lower temperature tends to be blue, and a higher temperature tends to be red.

[0054] In a specific application, the first temperature is 50 - 60 °C, and the preliminary heating duration is 10 min.

[0055] Step S4: According to the moisture distribution difference in each area of the first green compact, obtain the humidification amount required for each area of the first green compact; control the humidification device to apply the corresponding humidification amount to each area of the first green compact, so as to make the moisture distribution in each area of the first green compact uniform.

[0056] It should be noted that when the overall moisture distribution of the first green blank is uniform, it is very difficult to have the problem of "low moisture area: small shrinkage degree, and high moisture area: forming shear stress, resulting in the initiation of microcracks" during the drying process.

[0057] In this specific embodiment, step S4 includes:

[0058] Step S401: Obtain the area with the highest moisture content according to the moisture distribution differences in each area of the first green blank;

[0059] Step S402: Determine the moisture content difference between other areas and the area with the highest moisture content as the corresponding humidification amount;

[0060] Step S403: Control the humidification equipment to apply the corresponding humidification amount to each area of the first green blank so that the moisture distribution in each area of the first green blank is uniform.

[0061] Wherein, when there is one humidification equipment, control the humidification equipment to move for humidifying each area. When there are multiple humidification equipments, control the humidification equipments to humidify their corresponding areas.

[0062] It should be noted that using the area with the highest moisture content as a reference can avoid the situation where some humidities are higher than the reference and cannot be humidified.

[0063] In this specific embodiment, a plurality of heaters are arranged in the first drying chamber, and the heaters are evenly distributed to uniformly heat the first green blank. An infrared thermal imager is arranged at the top of the first drying chamber. The infrared thermal imager has different imaging colors for objects at different temperatures. A humidification equipment is also arranged in the first drying chamber, and the humidification equipment is used to perform corresponding humidification on the first green blank.

[0064] It should be noted that the embodiment of the present invention improves the structure of the drying chamber, which can effectively improve its drying effect and avoid the problem of quality decline of the ceramic fiber insulation board due to drying.

[0065] Step S5: Control the first drying chamber to uniformly heat the first green blank at a second temperature intermittently so that the internal moisture of the first green blank diffuses to the surface during the non-heating period, and a rough blank of the insulation board is obtained.

[0066] Wherein, the second temperature is greater than the first temperature.

[0067] In a specific application, the second temperature is 120 °C and the drying duration is 7 h.

[0068] In this specific embodiment, the heating method in step S5 is microwave heating. Microwave heating makes the internal temperature of the first green blank higher than the surface temperature, thus ensuring the same evaporation efficiency inside and outside.

[0069] It should be noted that microwave heating can cause the surface moisture to evaporate faster than the internal moisture migration speed, resulting in uneven internal and external shrinkage, stress concentration, cracking and other problems.

[0070] In this specific embodiment, step S5 further includes:

[0071] Controlling the first drying chamber to perform three-stage gradient heating on the first green blank in sequence at a third temperature, a fourth temperature, and a fifth temperature; wherein, the fifth temperature is greater than the fourth temperature, and the fourth temperature is greater than the third temperature.

[0072] It should be noted that gradient heating can sequentially remove the surface free water, internal capillary water, and internal bound water, and can also avoid the problem that the surface moisture evaporates faster than the internal moisture migration speed.

[0073] Step S6: Transfer the green blank of the insulation board to a sintering furnace for sintering to obtain a high-temperature resistant ceramic fiber insulation board.

[0074] In this specific embodiment, step S601: Transfer the green blank of the insulation board to a sintering furnace, and control the sintering furnace to heat up to 370 °C to remove the organic matter inside the green blank of the insulation board;

[0075] Step S602: In a reducing or inert atmosphere, control the sintering furnace to heat up to 1000 °C for sintering; then control the sintering furnace to cool down to 800 °C to enhance the crystallinity of the green blank of the insulation board and obtain a high-temperature resistant ceramic fiber insulation board.

[0076] In this specific embodiment, after step S6, the method further includes:

[0077] Cutting and polishing the high-temperature resistant ceramic fiber insulation board.

[0078] In the embodiment of the present invention, during drying, by collecting the moisture content of each area on the green blank of the ceramic fiber insulation board, and performing humidity compensation on each area of the green blank of the ceramic fiber insulation board according to the difference in moisture distribution, so that the moisture distribution of each area of the green blank of the ceramic fiber insulation board is uniform. By the above method, the embodiment of the present invention effectively avoids local shrinkage differences caused by uneven moisture distribution during the drying process, and reduces the quality of the finished product of the ceramic fiber insulation board.

[0079] In the embodiment of the present invention, the green blank of the ceramic fiber insulation board is dried by intermittent uniform heating, so that the internal moisture of the green blank of the ceramic fiber insulation board diffuses to the surface during the non-heating period, which can effectively avoid the surface moisture of the green blank of the ceramic fiber insulation board evaporating faster than the internal moisture migration speed, resulting in uneven internal and external shrinkage and generating stress.

[0080] In the embodiment of the present invention, by designing the structure of the drying chamber, it can have the functions of collecting moisture distribution, drying, and humidifying, reducing redundant equipment and processes.

[0081] The humidification in the embodiments of the present invention is based on the region with the highest water content, which can ensure uniform humidification in each region.

[0082] In summary, the embodiments of the present invention can improve the drying quality of the wet blanks of ceramic fiber insulation boards, avoid problems such as cracking and stress concentration, and thus improve the quality of the finished ceramic fiber insulation boards.

[0083] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0084] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

[0085] The above are only the preferred embodiments of the present invention and are not intended 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 are included in the protection scope of the present invention.

Claims

1. A preparation method of a high-temperature resistant ceramic fiber insulation board, characterized in that, The method includes: Step S1: Mix ceramic fiber and deionized water according to a first preset ratio, add a first amount of dispersant, and obtain a first suspension through high-speed shear stirring. Step S2: Inject the first suspension into a thermal insulation board model, and perform vacuum dehydration and pressing on the first suspension in the thermal insulation board model to obtain a first green body with a water content less than a first preset water content. Step S3: Place the first green body in a first drying chamber, control the first drying chamber to preliminarily heat the first green body at a first temperature, capture the temperature field corresponding to the surface of the first green body through an infrared thermal imager, and obtain the moisture distribution difference in each area of the first green body; wherein, moisture evaporation absorbs heat, and areas with different moisture contents have different heating degrees. Step S4: Obtain the humidification amount required for each area of the first green body according to the moisture distribution difference in each area of the first green body; control the humidification device to apply the corresponding humidification amount to each area of the first green body to make the moisture distribution in each area of the first green body uniform. Step S5: Control the first drying chamber to uniformly heat the first green body intermittently at a second temperature, so that the internal moisture of the first green body diffuses to the surface during the period without heating to obtain a rough thermal insulation board; wherein, the second temperature is greater than the first temperature. Step S6: Transfer the rough thermal insulation board to a sintering furnace for sintering to obtain a high-temperature resistant ceramic fiber thermal insulation board.

2. The preparation method of the high-temperature resistant ceramic fiber insulation board according to claim 1, wherein, A plurality of heaters are arranged in the first drying chamber, and the heaters are uniformly distributed to uniformly heat the first green body. An infrared thermal imager is arranged at the top of the first drying chamber. The infrared thermal imager has different imaging colors for objects with different temperatures. A humidification device is also arranged in the first drying chamber, and the humidification device is used to perform corresponding humidification on the first green body.

3. The preparation method of the high-temperature resistant ceramic fiber heat preservation board according to claim 1, characterized in that, The said Step S3 includes: Step S301: Place the first green body in the first drying chamber, and control the first drying chamber to preliminarily heat the first green body at a first temperature. Step S302: After the preliminary heating for a first period of time, stop heating, and control the infrared thermal imager to collect and capture the temperature field on the surface of the first green body. Step S303: Obtain the moisture distribution in each area of the first green body according to the color distribution corresponding to the temperature field, and further obtain the moisture distribution difference in each area of the first green body.

4. The method for preparing a high-temperature resistant ceramic fiber insulation board according to claim 1, characterized in that, The said Step S4 includes: Step S401: Obtain the area with the highest moisture content according to the moisture distribution difference in each area of the first green body. Step S402: Determine the difference in moisture content between other areas and the area with the highest moisture content as the corresponding humidification amount. Step S403: Control the humidification device to apply the corresponding humidification amount to each area of the first green body to make the moisture distribution in each area of the first green body uniform; wherein, when there is one humidification device, control the humidification device to move for humidifying each area, and when there are multiple humidification devices, control the humidification devices to humidify their corresponding areas.

5. The preparation method of the high-temperature resistant ceramic fiber heat insulation board according to claim 1, characterized in that, The ceramic fiber composition in the step S1 includes: alumina, silica and zirconia; wherein, alumina and silica are the main components, and the zirconia is used to improve the temperature resistance of the ceramic fiber.

6. The preparation method of the high-temperature resistant ceramic fiber heat preservation board according to claim 1, characterized in that, The heating method in the step S5 is microwave heating, and the microwave heating makes the internal temperature of the first green blank higher than the surface temperature, so as to ensure the same evaporation efficiency inside and outside.

7. The preparation method of the high-temperature resistant ceramic fiber insulation board according to claim 1, characterized in that The step S5 further includes: Controlling the first drying chamber to perform three-stage gradient heating on the first green blank at a third temperature, a fourth temperature and a fifth temperature in sequence; wherein, the fifth temperature is higher than the fourth temperature, and the fourth temperature is higher than the third temperature.

8. The preparation method of the high-temperature resistant ceramic fiber insulation board according to claim 1, characterized in that, The step S6 includes: Step S601: Transfer the rough blank of the heat preservation board to the sintering furnace, control the sintering furnace to heat up to 370 °C, and remove the organic matter inside the rough blank of the heat preservation board; Step S602: In a reducing or inert atmosphere, control the sintering furnace to heat up to 1000 °C for sintering; then control the sintering furnace to cool down to 800 °C to enhance the crystallinity of the rough blank of the heat preservation board and obtain the high-temperature resistant ceramic fiber heat preservation board.

9. The method for preparing a high-temperature resistant ceramic fiber insulation board according to claim 1, characterized in that, After the step S6, the method further includes: Cutting and polishing the high-temperature resistant ceramic fiber heat preservation board.

Images