Calcination-free ceramic fiber board and preparation method thereof

Abstract

The invention provides a calcination-free ceramic fiber board and a preparation method thereof.The method comprises the following steps that S10, ceramic fibers, ceramic filler and a silane coupling agent are dispersed in water, the silane coupling agent is grafted to the surfaces of the ceramic fibers and the ceramic filler, and a first mixed solution is obtained; wherein the silane coupling agent comprises an amino silane coupling agent and / or a fluorine-containing silane coupling agent; s20, adding an epoxy group silane coupling agent into a silica sol binder to graft epoxy groups on the surface of silicon dioxide in the silica sol binder to obtain a second mixed solution; and S30, the first mixed solution and the second mixed solution are mixed to obtain slurry, the slurry is subjected to wet vacuum forming, and the calcination-free ceramic fiber board is obtained after drying. The calcination-free ceramic fiber board has good heat resistance and strength.

Description

Technical Field

[0001] The present application relates to the technical field of ceramic fiberboards, and in particular to a calcination-free ceramic fiberboard and a preparation method thereof. Background Art

[0002] Ceramic fiberboard, a lightweight, high-temperature-resistant insulation material, has been widely used in high-temperature industrial furnace linings, thermal equipment pipeline insulation, and protective materials in specialized applications. Traditionally, ceramic fiberboard is produced using either dry or wet processes. The wet process has become the mainstream due to its uniform fiber distribution and stable board performance. The wet process involves shredding the raw ceramic fiber and mixing it with a binder to create a slurry. This slurry is then vacuum-formed in a water-washed mold. Calcination is then performed to enhance the heat resistance and strength of the ceramic fiberboard, but this significantly increases production costs.

[0003] Calcination-free ceramic fiberboard can be cured at low temperature without going through a high-temperature calcination process, which has low production energy consumption and reduces harmful gas emissions. However, since it has not been calcined, the heat resistance and strength of calcination-free ceramic fiberboard are generally relatively low. Therefore, how to improve the heat resistance and strength of calcination-free ceramic fiberboard is a key research direction in this field.

[0004] For example, patent CN118754653A discloses a high-temperature resistant ceramic fiberboard and its preparation method. The method comprises the following steps: S10: dispersing refractory ceramic fibers, refractory ceramic fillers, and a silica sol binder in water to obtain a mixed solution; S20: adding an acrylamide monomer and a crosslinking agent to the mixed solution, initiating a polymerization reaction to cause flocculation to obtain a slurry; S30: wet vacuum forming the slurry, and drying it to obtain a high-temperature resistant ceramic fiberboard. By using an acrylamide monomer for in-situ crosslinking polymerization and combining it with a silica sol binder, the refractory ceramic fibers and refractory ceramic fillers can be rapidly flocculated and settled. During the subsequent drying process, the crosslinked acrylamide polymer and silica sol binder are less likely to float, thereby effectively improving the heat resistance and strength of the high-temperature resistant ceramic board.

[0005] The above-mentioned high-temperature resistant ceramic fiber board has not been calcined and has certain heat resistance and strength. However, the inventors found that although the addition of acrylamide monomers and cross-linking agents can effectively improve the problem of binder floating, thereby improving the heat resistance and strength of the high-temperature ceramic fiber board, since organic binders are introduced in this process, and organic binders have poor stability at high temperatures, they may affect the stability of the ceramic fiber board at higher temperatures. Therefore, it is necessary to provide a calcination-free ceramic fiber board that does not require the addition of organic binders and has good heat resistance and strength. Summary of the Invention

[0006] The present application provides a calcination-free ceramic fiberboard and a preparation method thereof. The calcination-free ceramic fiberboard does not contain an organic binder and has good heat resistance and strength.

[0007] In a first aspect, the present application provides a method for preparing a calcination-free ceramic fiberboard, comprising the following steps:

[0008] Step S10: dispersing ceramic fibers, ceramic fillers, and a silane coupling agent in water, and grafting the silane coupling agent onto the surfaces of the ceramic fibers and ceramic fillers to obtain a first mixed solution; wherein the silane coupling agent includes an aminosilane coupling agent and / or a fluorine-containing silane coupling agent;

[0009] Step S20: adding an epoxy silane coupling agent to the silica sol binder to graft epoxy groups onto the surface of the silica in the silica sol binder to obtain a second mixed solution;

[0010] Step S30: mixing the first mixed liquid and the second mixed liquid to obtain a slurry, wet vacuum forming the slurry, and drying it to obtain a calcination-free ceramic fiberboard.

[0011] According to the present application, the calcination-free ceramic fiber board can avoid the use of organic binders. By grafting amino groups and / or fluorine atoms on the surface of ceramic fibers and ceramic fillers, the amino groups and / or fluorine atoms can promote the coagulation and precipitation of ceramic fibers and ceramic fillers with silica in the silica sol binder. In the subsequent drying process, the epoxy groups on the surface of silica can react with the hydroxyl groups and / or amino groups on the surface of the ceramic fibers and ceramic fillers, so that the components in the ceramic fiber board are tightly combined, thereby obtaining a calcination-free ceramic fiber board with good heat resistance and strength.

[0012] In some embodiments, the ceramic fiber includes at least one of polycrystalline mullite fiber, zirconia fiber, and magnesium aluminum spinel fiber; and the length of the ceramic fiber is 0.1 to 10 mm.

[0013] In some embodiments, the ceramic filler includes at least one of polycrystalline mullite particles, zirconia particles, and magnesia-aluminum spinel particles; and the average particle size of the ceramic filler is 5 to 200 nm.

[0014] In some embodiments, step S10 specifically includes: dispersing 10 parts by mass of ceramic fiber, 15 to 40 parts by mass of ceramic filler and 5 to 20 parts by mass of silane coupling agent in 300 to 500 parts by mass of water, ultrasonically dispersing, and stirring at 30 to 60° C. for 1 to 4 hours to obtain a first mixed solution.

[0015] In some embodiments, the silane coupling agent includes an aminosilane coupling agent and a fluorine-containing silane coupling agent, and the mass ratio of the aminosilane coupling agent to the fluorine-containing silane coupling agent is 1:0.1-0.4.

[0016] In some embodiments, step S20 specifically includes: adding 1 to 5 parts by mass of an epoxy silane coupling agent to 5 to 20 parts by mass of a silica sol binder having a solid content of 20 wt% to 40 wt%, stirring and reacting at 30 to 60° C. for 1 to 4 hours to obtain a second mixed solution.

[0017] In some embodiments, in step S30, the wet vacuum forming specifically includes: using a vacuum degree of 0.03 to 0.06 MPa for filtration, and using a roller to press with a roller pressure of 0.05 to 0.1 MPa.

[0018] In some embodiments, in step S30, the drying conditions include: drying at 100-150° C. for 5-12 hours.

[0019] In a second aspect, the present application provides a calcination-free ceramic fiberboard, which is prepared according to the method described in any embodiment of the first aspect.

[0020] In some embodiments, the permanent linear change rate of the calcination-free ceramic fiber board in the thickness direction after being kept at 1850° C. for 24 hours is no more than 1%. DETAILED DESCRIPTION

[0021] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0022] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0024] As described in the background art above, the calcination-free ceramic fiberboard can be cured at a low temperature without undergoing a high-temperature calcination process, which reduces production energy consumption and reduces harmful gas emissions.

[0025] The current problem with unfired ceramic fiberboard is that in order to achieve tight bonding of the various components of the ceramic fiberboard without calcination, the relevant technology generally uses inorganic binders and organic binders to achieve bonding of the various components in the ceramic fiberboard. However, the organic binders have poor heat resistance and are easily invalidated at high temperatures, resulting in poor heat resistance and strength of the unfired ceramic fiberboard.

[0026] Based on this, the present application provides a calcined-free ceramic fiberboard and a method for preparing the same. By employing a specific process, the use of organic binders can be avoided. By grafting and modifying the ceramic fibers, ceramic fillers, and silica sol, a tight bond between the components is achieved, effectively improving the heat resistance and strength of the calcined-free ceramic fiberboard. The specific embodiments of the present application are described in detail below.

[0027] In a first aspect, the present application provides a method for preparing a calcination-free ceramic fiberboard, comprising the following steps:

[0028] Step S10: dispersing ceramic fibers, ceramic fillers, and a silane coupling agent in water, and grafting the silane coupling agent onto the surfaces of the ceramic fibers and ceramic fillers to obtain a first mixed solution; wherein the silane coupling agent includes an aminosilane coupling agent and / or a fluorine-containing silane coupling agent;

[0029] Step S20: adding an epoxy silane coupling agent to the silica sol binder to graft epoxy groups onto the surface of the silica in the silica sol binder to obtain a second mixed solution;

[0030] Step S30: mixing the first mixed liquid and the second mixed liquid to obtain a slurry, wet vacuum forming the slurry, and drying it to obtain a calcination-free ceramic fiberboard.

[0031] According to the present application, the calcination-free ceramic fiber board can avoid the use of organic binders. By grafting amino groups and / or fluorine atoms on the surface of ceramic fibers and ceramic fillers, the amino groups and / or fluorine atoms can promote the coagulation and precipitation of ceramic fibers and ceramic fillers with silica in the silica sol binder. In the subsequent drying process, the epoxy groups on the surface of silica can react with the hydroxyl groups and / or amino groups on the surface of the ceramic fibers and ceramic fillers, so that the components in the ceramic fiber board are tightly combined, thereby obtaining a calcination-free ceramic fiber board with good heat resistance and strength.

[0032] Specifically, in step S10, ceramic fiber and ceramic filler are used as the main materials of the unfired ceramic fiber board. Since the heat resistance and strength of the ceramic fiber board are highly correlated with the density of the unfired ceramic fiber board, the combination of ceramic fiber and ceramic filler is conducive to further improving the density of the ceramic fiber board, thereby further improving the heat resistance and strength of the ceramic fiber board. At the same time, a silane coupling agent is used to graft and modify the ceramic fiber and ceramic filler, wherein the silane coupling agent includes an aminosilane coupling agent and / or a fluorine-containing silane coupling agent. Since the silica particles in the silica sol binder are negatively charged, the grafted positively charged amino group can promote the flocculation and adsorption of the ceramic fiber and ceramic filler with the silica particles in the silica sol. The fluorine atoms grafted on the surface of the ceramic fiber and ceramic filler can bind silica to the surface of the ceramic fiber and ceramic filler through a strong interaction with silica, thereby making the silica particles in the silica sol more easily evenly dispersed on the surface of the ceramic fiber and ceramic filler, so that the components are tightly bonded, thereby improving the heat resistance and strength of the ceramic fiber board.

[0033] In step S20, in order to improve the bonding performance of silica sol to ceramic fibers and ceramic fillers, epoxy groups are grafted onto the surface of silica in the silica sol using an epoxy silane coupling agent. The epoxy groups on the surface of silica can react with hydroxyl groups and / or amino groups on the surfaces of ceramic fibers and ceramic fillers during the subsequent drying process, thereby tightly bonding the components in the ceramic fiber board. It can be understood that the reaction of epoxy groups with hydroxyl groups and / or amino groups can form flexible ether bonds and / or etheramine bonds, which can disperse the stress inside the ceramic fiber board to a certain extent, thereby improving the flexural strength of the ceramic fiber board.

[0034] In step S30, the first mixed liquid and the second mixed liquid are mixed to obtain a slurry, and wet vacuum forming is performed, which is beneficial to increasing the density of the wet blank after forming, thereby increasing the density of the unfired ceramic fiber board, and enabling the unfired ceramic fiber board to have good heat resistance and strength; in the subsequent drying process, the ceramic fibers and ceramic fillers react with the groups on the surface of the silica in the silica sol, thereby increasing the bonding force between the components in the ceramic fiber board and improving the strength of the unfired ceramic fiber board.

[0035] In some embodiments, the ceramic fiber includes at least one of polycrystalline mullite fiber, zirconia fiber, and magnesium aluminum spinel fiber; and the length of the ceramic fiber is 0.1 to 10 mm.

[0036] In some of the above embodiments, since the main heat resistance of the calcination-free ceramic fiber board is related to the ceramic fiber raw material, the ceramic fiber with good heat resistance can ensure that it has good heat resistance. An exemplary ceramic fiber with good heat resistance is listed. The use of the above fiber can make the ceramic fiber board have good heat resistance. At the same time, it can be understood that the ceramic fibers include but are not limited to the above-mentioned ones. Those skilled in the art can choose other ceramic fibers according to actual needs. At the same time, the length of the ceramic fiber is limited to 0.1 to 10 mm. Shorter ceramic fibers are conducive to further improving the density of the ceramic fiber board, thereby further improving the heat resistance and strength of the ceramic fiber board.

[0037] In some embodiments, the ceramic filler includes at least one of polycrystalline mullite particles, zirconia particles, and magnesia-aluminum spinel particles; and the average particle size of the ceramic filler is 5 to 200 nm.

[0038] In some of the above embodiments, since the main heat resistance of the calcined-free ceramic fiber board is related to the ceramic fiber raw material, a ceramic filler with good heat resistance can ensure that it has good heat resistance. An example of a ceramic filler with good heat resistance is listed. The use of the above filler can make the ceramic fiber board have good heat resistance. At the same time, it can be understood that the ceramic filler includes but is not limited to the above-mentioned types. Those skilled in the art can select other ceramic fillers according to actual needs. At the same time, the average particle size of the ceramic filler is limited to 5 to 200 nm. Ceramic fillers with smaller particle sizes are conducive to further improving the density of the ceramic fiber board, thereby further improving the heat resistance and strength of the ceramic fiber board.

[0039] In some embodiments, step S10 specifically includes dispersing 10 parts by mass of ceramic fiber, 15-40 parts by mass of ceramic filler, and 5-20 parts by mass of silane coupling agent in 300-500 parts by mass of water, performing ultrasonic dispersion, and stirring at 30-60°C for 1-4 hours to obtain a first mixed solution. Based on the above embodiments, the conditions for modifying the ceramic fiber and ceramic filler with the silane coupling agent are specifically defined, under which the ceramic fiber and ceramic filler can be grafted with the silane coupling agent.

[0040] In some embodiments, the silane coupling agent includes an aminosilane coupling agent and a fluorine-containing silane coupling agent, and the mass ratio of the aminosilane coupling agent to the fluorine-containing silane coupling agent is 1:0.1 to 0.4.

[0041] In some of the above embodiments, the components of the silane coupling agent are further limited, wherein the aminosilane coupling agent can graft amino groups on the surface of the ceramic fiber and ceramic filler. In addition to adsorbing the colloidal particles in the silica sol through electrostatic interaction, the amino group can also cross-link with the epoxy group on the surface of the silica in the silica sol, thereby significantly improving the bonding force of the various components in the ceramic fiber board. However, as the drying proceeds, the electrostatic effect weakens, which will cause the silica in the silica sol to float, resulting in an uneven distribution of silica in the ceramic fiber board, affecting the heat resistance and strength of the ceramic fiber board. In this embodiment, by adding a certain amount of fluorine-containing silane coupling agent, fluorine-containing chain segments are grafted on the surface of the ceramic fiber and ceramic filler. The fluorine atoms on the fluorine-containing chain segments can be used to strongly interact with the silica colloidal particles to adsorb the colloidal particles in the silica sol, and limit the floating of the silica colloidal particles during the drying process, making the silica distribution uneven, and further improving the heat resistance and strength of the calcined ceramic fiber board.

[0042] It should be noted that aminosilane coupling agent and fluorine-containing silane coupling agent have well-known meanings in the art. Aminosilane coupling agent is a silane coupling agent containing an amino group. As an example, the aminosilane coupling agent may be 3-aminopropyltriethoxysilane; fluorine-containing silane coupling agent is a silane coupling agent containing fluorine atoms. As an example, the fluorine-containing silane coupling agent may be (3,3,3,-trifluoropropyl)methyldimethoxysilane.

[0043] In some embodiments, step S20 specifically includes adding 1 to 5 parts by weight of an epoxy silane coupling agent to 5 to 20 parts by weight of a silica sol binder having a solid content of 20 wt% to 40 wt%, stirring the mixture at 30 to 60°C for 1 to 4 hours to obtain a second mixed solution. Based on the above embodiments, the conditions for modifying the silica sol binder with the epoxy silane coupling agent are specifically defined, under which epoxy groups can be grafted onto the silica particles in the silica sol binder. It is understood that the silica sol binder is a silica sol dispersed in water. By way of example, the silica sol binder used in this application is a silica sol with a solid content of 30 wt% and a silica particle size of 10 to 15 nm. The term "epoxy silane coupling agent" has a well-known meaning in the art and is a silane coupling agent containing epoxy groups. By way of example, the epoxy silane coupling agent can be γ-glycidoxypropyltrimethoxysilane.

[0044] In some embodiments, in step S30, the wet vacuum forming process specifically includes: performing filtration using a vacuum degree of 0.03 to 0.06 MPa, and rolling using a pressure roller at a pressure of 0.05 to 0.1 MPa. Based on the above embodiment, performing vacuum filtration and rolling under the above conditions can further increase the density of the ceramic fiber board, thereby further improving the heat resistance and strength of the unfired ceramic fiber board.

[0045] In some embodiments, in step S30, the drying conditions include: drying at 100-150° C. for 5-12 hours.

[0046] In a second aspect, the present application provides a calcination-free ceramic fiberboard prepared according to the method of any embodiment of the first aspect.

[0047] According to the present application, since the calcination-free ceramic fiber board is prepared according to the method of any embodiment of the first aspect, it has the beneficial effects of the first aspect.

[0048] In some embodiments, the permanent linear change rate of the unfired ceramic fiberboard in the thickness direction after being heated at 1850°C for 24 hours is no more than 1%. Based on the above embodiments, the unfired ceramic fiberboard does not require the use of an organic binder. By grafting and modifying the ceramic fibers, ceramic fillers, and silica sol binder, the interaction between the components of the ceramic fiberboard can significantly improve the bonding strength, thereby providing excellent heat resistance and strength.

[0049] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0050] Zirconia fiber: The raw material is zirconia fiber cotton purchased from Jinan Huolong Thermal Ceramics Co., Ltd., with a product code of HLG-911, a diameter of 3 to 6 μm, and a length of 30 to 300 mm. The zirconia fiber cotton is dispersed in water and chopped using a ceramic fiber chopper, and sieved and washed with a filter with a mesh size of 5 mm to obtain zirconia fiber for use.

[0051] Alumina powder was purchased from Zibo Weishuo Fine Ceramic Materials Co., Ltd., model: high-temperature low-sodium alumina powder, with an average particle size of 5-200 nm, α-alumina content >94%, sodium oxide content <0.1%, and iron oxide content <0.2%.

[0052] Silica sol was purchased from Shandong Better New Materials Co., Ltd., model SS3015, particle size 10-15 nm, and silica mass content 30%±1%.

[0053] Example 1

[0054] Preparation of calcined ceramic fiberboard:

[0055] 100 g of zirconia fiber, 350 g of alumina powder, 50 g of 3-aminopropyltriethoxysilane, and 10 g of (3,3,3,-trifluoropropyl)methyldimethoxysilane were ultrasonically dispersed in 4500 g of water, and stirred at 50° C. for 2 h to obtain a first mixed solution.

[0056] 30 g of γ-glycidyloxypropyltrimethoxysilane was added to 120 g of 30 wt % silica sol binder, and the mixture was stirred and reacted at 50° C. for 2 h to obtain a second mixed solution.

[0057] The first mixed liquid and the second mixed liquid were mixed to obtain a slurry, which was filtered using a vacuum degree of 0.05 MPa and rolled using a roller with a rolling pressure of 0.05 MPa to obtain a wet blank, which was then dried at 115° C. for 8 h to obtain a calcination-free ceramic fiber board.

[0058] Example 2

[0059] Preparation of calcined ceramic fiberboard:

[0060] 100 g of zirconia fiber, 350 g of alumina powder, and 60 g of 3-aminopropyltriethoxysilane were ultrasonically dispersed in 4500 g of water, and the mixture was stirred and reacted at 50° C. for 2 h to obtain a first mixed solution.

[0061] 30 g of γ-glycidyloxypropyltrimethoxysilane was added to 120 g of 30 wt % silica sol binder, and the mixture was stirred and reacted at 50° C. for 2 h to obtain a second mixed solution.

[0062] The first mixed liquid and the second mixed liquid were mixed to obtain a slurry, which was filtered using a vacuum degree of 0.05 MPa and rolled using a roller with a rolling pressure of 0.05 MPa to obtain a wet blank, which was then dried at 115° C. for 8 h to obtain a calcination-free ceramic fiber board.

[0063] Example 3

[0064] Preparation of calcined ceramic fiberboard:

[0065] 100 g of zirconia fiber, 350 g of alumina powder, and 60 g of (3,3,3,-trifluoropropyl)methyldimethoxysilane were ultrasonically dispersed in 4500 g of water, and the mixture was stirred at 50° C. for 2 h to obtain a first mixed solution.

[0066] 30 g of γ-glycidyloxypropyltrimethoxysilane was added to 120 g of 30 wt % silica sol binder, and the mixture was stirred and reacted at 50° C. for 2 h to obtain a second mixed solution.

[0067] The first mixed liquid and the second mixed liquid were mixed to obtain a slurry, which was filtered using a vacuum degree of 0.05 MPa and rolled using a roller with a rolling pressure of 0.05 MPa to obtain a wet blank, which was then dried at 115° C. for 8 h to obtain a calcination-free ceramic fiber board.

[0068] Comparative Example 1

[0069] Preparation of calcined ceramic fiberboard:

[0070] 100g of zirconia fiber and 350g of alumina powder were dispersed in 4500g of water. After uniform dispersion, 120g of 30wt% silica sol binder was added to obtain a mixed solution. 20g of polyacrylamide was then added and flocculated and precipitated to obtain a slurry.

[0071] The product was filtered using a vacuum degree of 0.05 MPa and rolled using a roller with a rolling pressure of 0.05 MPa to obtain a wet blank, which was then dried at 115° C. for 8 h to obtain a calcination-free ceramic fiber board.

[0072] The unsintered ceramic fiber boards obtained in Examples 1 to 3 and Comparative Example 1 were tested for their heating permanent linear change rate in the thickness direction after being heated at 1850°C for 24 hours according to GB / T 17911-2018, and for their flexural strength according to GB / T 3001-2017. The results are shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] According to Table 1, the heat resistance and strength of the unsintered ceramic fiber boards obtained in each embodiment of the present application are better than those of the comparative example. The heat resistance and strength of the comparative example 1 are poor. The reason is that it uses polyacrylamide organic binder in combination with silica sol binder to bond the ceramic fiber and ceramic filler. On the one hand, the binder easily floats during the drying process, resulting in poor bonding effect. On the other hand, the organic binder has poor heat resistance. At high temperatures, the organic binder will gradually decompose and become ineffective, resulting in a large heating permanent linear change rate in the thickness direction of the unsintered ceramic fiber board in comparative example 1 and a small flexural strength.

[0077] According to Examples 1 to 3, the heat resistance and strength of the unfired ceramic fiber board obtained in Example 1 are the best. The reason may be that: in Example 2, only aminosilane coupling agent is used to modify the ceramic fiber and ceramic filler. As the drying proceeds, the electrostatic effect weakens, which may lead to uneven distribution of silica gel particles in the ceramic fiber board, resulting in the heat resistance and strength of the obtained unfired ceramic fiber board being inferior to those in Example 1; in Example 3, only fluorine-containing silane coupling agent is used to modify the ceramic fiber and ceramic filler. Although the fluorine-containing chain segments on the surface of the ceramic fiber and ceramic filler can stably adsorb silica gel particles, the reaction activity of the epoxy groups on the surface of the silica gel particles and the hydroxyl groups on the surface of the ceramic fiber and ceramic filler is weaker than that of the amino group, resulting in the bonding force between the components being inferior to that in Example 1. Therefore, the heat resistance and strength of the obtained unfired ceramic fiber board are inferior to those in Example 1.

[0078] In addition, the inventors found that the flexural strength of Examples 1 and 2 was significantly improved compared to that of Example 3, indicating that the cross-linking of ceramic fibers and ceramic fillers with the silica sol binder through amino and epoxy reactions can significantly improve the bonding strength of the components. At the same time, the etheramine bonds formed by the reaction can effectively disperse the stress on the ceramic fiber board, thereby significantly improving the flexural strength of the ceramic fiber board.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a calcination-free ceramic fiberboard, characterized in that: The following steps are involved: step S10: dispersing ceramic fibers, ceramic fillers, and a silane coupling agent in water, and grafting the silane coupling agent onto the surfaces of the ceramic fibers and ceramic fillers to obtain a first mixed solution; wherein the silane coupling agent includes an aminosilane coupling agent and / or a fluorine-containing silane coupling agent; Step S20: adding an epoxy silane coupling agent to the silica sol binder to graft epoxy groups onto the surface of the silica in the silica sol binder to obtain a second mixed solution; Step S30: mixing the first mixed liquid and the second mixed liquid to obtain a slurry, wet vacuum forming the slurry, and drying it to obtain a calcination-free ceramic fiberboard.

2. The method according to claim 1, characterized in that The ceramic fiber includes at least one of polycrystalline mullite fiber, zirconia fiber, and magnesium aluminum spinel fiber; The length of the ceramic fiber is 0.1 to 10 mm.

3. The method according to claim 1, characterized in that The ceramic filler includes at least one of polycrystalline mullite particles, zirconium oxide particles, and magnesium aluminum spinel particles; The average particle size of the ceramic filler is 5 to 200 nm.

4. The method according to claim 1, wherein The step S10 specifically includes: 10 parts by mass of ceramic fiber, 15-40 parts by mass of ceramic filler and 5-20 parts by mass of silane coupling agent are dispersed in 300-500 parts by mass of water, ultrasonically dispersed, and stirred at 30-60° C. for 1-4 hours to obtain a first mixed solution.

5. The method according to claim 1 or 4, characterized in that The silane coupling agent includes an aminosilane coupling agent and a fluorine-containing silane coupling agent, and the mass ratio of the aminosilane coupling agent to the fluorine-containing silane coupling agent is 1:0.1-0.

4.

6. The method according to claim 1 or 4, characterized in that The step S20 specifically includes: Add 1 to 5 parts by mass of epoxy silane coupling agent to 5 to 20 parts by mass of silica sol binder with a solid content of 20 wt% to 40 wt%, and stir at 30 to 60° C. for 1 to 4 hours to obtain a second mixed solution.

7. The method according to claim 6, characterized in that In the step S30, the wet vacuum forming specifically includes: using a vacuum degree of 0.03-0.06 MPa for filtration, and using a roller to press with a roller pressure of 0.05-0.1 MPa.

8. The method according to claim 6, characterized in that In the step S30, the drying conditions include: drying at 100-150° C. for 5-12 hours.

9. A calcination-free ceramic fiberboard, characterized in that: Prepared according to the method according to any one of claims 1 to 8.

10. The calcination-free ceramic fiber board according to claim 9, characterized in that: The calcination-free ceramic fiber board has a heating permanent line change rate of no more than 1% in the thickness direction when kept at 1850° C. for 24 hours.

Images