A 1350 degree celsius biodegradable high-temperature-resistant ceramic fiber and a preparation method thereof

Abstract

This invention discloses a 1350℃ biosoluble high-temperature resistant ceramic fiber and its preparation method, belonging to the field of soluble fiber technology. The key technical point is a 1350℃ biosoluble high-temperature resistant ceramic fiber, wherein the ceramic fiber comprises the following raw materials by weight percentage: SiO2: 75-78%, MgO: 18-23%, Al2O3: 1.5-2.8%, LiO2: 0.4-0.6%, SrO: 0.4-0.8%, with the balance being other metal oxides. This achieves the effect of meeting the requirements for higher operating temperatures and replacing traditional ceramic fibers.

Description

Technical Field

[0001] This invention relates to the field of soluble fiber technology, and in particular to a 1350℃ biosoluble high-temperature resistant ceramic fiber and its preparation method. Background Technology

[0002] In industrial production and high-temperature applications, the performance of thermal insulation materials is crucial. With the continuous development of industrial technology, the demand for high-temperature resistant materials is increasing, especially those that can function stably under high-temperature conditions. These materials are of great significance for improving production efficiency and reducing energy consumption. Materials such as ceramic fibers and soluble fibers are increasingly being used in high-temperature insulation, providing effective solutions for numerous high-temperature operating conditions and driving the development of related industries.

[0003] In previous applications of high-temperature insulation materials, common solutions included the use of ceramic fibers and soluble fibers. Ceramic fibers generally refer to aluminosilicate fibers of Al2O3-SiO2 and Al2O3-SiO2-ZrO2, also known as refractory ceramic fibers. They provide a certain degree of insulation in high-temperature environments and are widely used in various high-temperature equipment. Soluble fibers, as a substitute for ceramic fibers, refer to artificial glass silicate fibers with an alkali and alkaline earth metal oxide content >18%. Currently, soluble fibers with temperature ratings of 1200℃ and 1300℃ are available on the market, which also meet some high-temperature requirements to a certain extent.

[0004] However, these existing materials have significant drawbacks. The inhalable dust generated by refractory ceramic fibers is similar to that of most glass fibers and mineral wool, and is considered an inhalable substance by the World Health Organization. As a durable fiber, it has been classified as a Group 2B carcinogen by many organizations and faces increasingly stringent airborne dust restrictions. While soluble fibers have certain advantages, they currently cannot meet the higher operating temperature requirements. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a 1350℃ biosoluble high-temperature resistant ceramic fiber and its preparation method, thereby meeting the requirements for higher operating temperatures and replacing traditional ceramic fibers.

[0006] The first aspect of this invention is to provide a 1350℃ biosoluble high-temperature resistant ceramic fiber, which adopts the following technical solution: A biosoluble high-temperature resistant ceramic fiber with a temperature of 1350℃, the ceramic fiber comprising the following raw materials by weight percentage: SiO2: 75-78%, MgO: 18-23%, Al2O3: 1.5-2.8%, LiO2: 0.4-0.6%, SrO: 0.4-0.8%, with the balance being other metal oxides.

[0007] In a preferred embodiment, the ceramic fiber comprises the following raw materials by weight percentage: SiO2: 75-77%, MgO: 18-20%, Al2O3: 2.4-2.8%, LiO2: 0.4-0.5%, SrO: 0.4-0.6%, with the balance being other metal oxides.

[0008] By employing the above technical solution, SiO2, MgO, Al2O3, LiO2, SrO, and other impurity metal oxides work together to enable ceramic fibers to achieve an operating temperature of 1350℃. The SiO2 content is 75-78%, forming the basic three-dimensional network skeleton of the ceramic fiber and maintaining its basic structure. A moderate increase in SiO2 content enhances the fiber's high-temperature resistance, but excessive content may reduce its flexibility, making it brittle and prone to breakage. The MgO content is 18-23%, improving the fiber's structural stability and corrosion resistance. Working synergistically with SiO2, it can partially enter the network or fill the gaps between networks, improving the fiber's high-temperature resistance. Higher MgO content helps enhance the fiber's resistance to chemical corrosion at high temperatures, but excessive content may affect the fiber's formability. The Al2O3 content is 1.5-2.8%, improving the fiber's mechanical strength and thermal stability. A moderate increase further enhances the fiber's stability at high temperatures, but excessive content may increase production costs and affect the solubility of the ceramic fiber. The LiO2 content... With a content of 0.4-0.6%, lithium oxide can form eutectic compounds with silicon oxide and aluminum oxide with very low melting points, thereby lowering the melting point and promoting the melting of raw materials. Too low a content is not conducive to the melting process, while too high a content may reduce the high-temperature resistance of the fiber. This is because when the lithium oxide content is low, small-radius lithium ions can enter the gaps in the glass network structure, which can play a certain role in repairing the broken network. At the same time, it can reduce the high-temperature viscosity and crystallization tendency of the glass melt, help the fiber maintain a uniform glassy state during molding, and promote the formation of fine and stable high-melting-point spodumene crystals at high temperatures. These crystals have a low coefficient of thermal expansion and can be well bonded to the glass matrix, effectively pinning the fiber structure, thus helping to resist shrinkage at high temperatures. However, too high a lithium oxide content may induce liquid-phase separation of the glass, forming a silicon-rich phase and a lithium-rich phase. The lithium-rich phase will soften first at high temperatures, becoming the source of shrinkage.

[0009] A SrO content of 0.4-0.8% helps improve the crystallinity and high-temperature strength of the fiber. The combination of LiO2 and SrO optimizes the fiber structure, enabling the fiber to withstand higher temperatures. Furthermore, the combination of LiO2 and SrO can mutually restrain each other within the three-dimensional network framework, slowing down ion diffusion and thus inhibiting shrinkage. When the lithium content exceeds the limits specified in this application, this balance is disrupted or even disappears, and the diffusion of single, high-concentration lithium ions accelerates structural rearrangement and shrinkage at high temperatures. Appropriately increasing the SrO content can enhance the fiber's strength at high temperatures, but excessive amounts may affect the temperature resistance of the ceramic fiber. The specific proportions of these raw materials not only improve the service temperature of the ceramic fiber but also ensure its excellent overall performance. Simultaneously, the ceramic fiber is biosoluble, avoiding the potential carcinogenic risks associated with traditional refractory ceramic fibers.

[0010] In a preferred embodiment, the weight percentages of the other metal oxides are CaO: 0.3-0.5%, Fe2O3: 0.1-0.3%, and K2O: 0.05-0.20%.

[0011] By adopting the above technical solution, CaO, Fe2O3, and K2O serve as impurity metal oxides, working in conjunction with other metal oxides such as SiO2, MgO, Al2O3, LiO2, and SrO. Based on the basic high-temperature resistant structure formed by SiO2 and MgO, an appropriate amount of CaO helps improve the high-temperature stability of the ceramic fiber, preventing the collapse and deformation of the fiber structure at 1350℃. However, excessive addition of calcium oxide loosens the three-dimensional network structure of silica and reduces the high-temperature viscosity of the glass melt. Lower viscosity reduces the resistance to atomic rearrangement, making it easier to flow at 1350℃, thus significantly reducing its resistance to linear shrinkage and affecting the high-temperature resistance of the ceramic fiber. Fe2O3 can lower the melting point of the fiber to a certain extent, giving it better fluidity and formability at high temperatures while ensuring the stability of the overall structure. K2O can improve the chemical activity of the fiber and enhance the bonding force between the fiber and other components, enabling the ceramic fiber to meet the 1350℃ operating temperature requirement. When the CaO content is below 0.3%, high-temperature stability may be insufficient, and the fiber may become structurally unstable at 1350℃; above 0.5%, it may affect the fiber's toughness and flexibility. When the Fe2O3 content is below 0.1%, the fiber's formability may deteriorate; above 0.3%, it may lead to a decrease in the fiber's high-temperature resistance. When the K2O content is below 0.05%, the bonding force between the fiber's components may be insufficient; above 0.20%, it may increase the fiber's chemical activity at high temperatures, accelerating fiber aging and damage.

[0012] A second aspect of the present invention is to provide a method for preparing 1350℃ biosoluble high-temperature resistant ceramic fibers as described above, comprising the following steps: S1. Mix the above-mentioned raw materials and add them to the resistance furnace for melting; S2. After melting, the fibers are spun into fibers by a spinning roller. The fibers are collected to form a continuous fiber felt, which is then needle-punched and calcined at high temperature to form a fiber blanket.

[0013] In a preferred embodiment, the melting temperature is 1850-2000°C.

[0014] In a preferred embodiment, the spinning speed of the spinning roller is 9500-11500 rpm.

[0015] By adopting the above technical solution, the spinning speed of the spinning roller is controlled between 9500-11500 rpm. If the speed is too low, the fiber forming effect may be poor, the fiber thickness may be uneven, and the slag ball rate may increase. If the speed is too high, the fibers may be too thin and short, affecting the strength of the fiber blanket. This speed range ensures good fiber forming, which helps to ensure that the fiber blanket has high strength, low slag ball rate, and good high temperature resistance.

[0016] In a preferred embodiment, the fiber blanket has a strength >50 kPa, a slag ball ratio (>45 μm) <48%, and a linear shrinkage rate of <4% after heating at 1350°C for 24 hours.

[0017] In summary, the present invention has the following beneficial effects: the combination of raw materials in this application can ensure that the fiber has good viscosity and structural stability at high temperature, so that the service temperature of the obtained soluble ceramic fiber can meet the service requirement of 1350℃. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments. All reagents, unless otherwise specified, are commercially available conventional reagent products. Example 1

[0019] A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃ comprises the following raw materials by weight percentage: SiO2: 76.77%, MgO: 19.11%, Al2O3: 2.56%, LiO2: 0.46%, SrO: 0.44%, CaO: 0.46%, Fe2O3: 0.14%, K2O: 0.06%; Its preparation method adopts the following steps: S1. Mix the above raw materials and add them to a resistance furnace for melting, controlling the temperature of the molten liquid to be 1860±10℃; S2. The molten liquid is poured into the spinning roller of the spinning machine through the outlet of the resistance furnace. The spinning speed of the spinning roller is controlled at 9500 rpm. After being spun into fibers, the fibers are collected in the cotton collection box to form a continuous fiber felt. The fiber felt is then needle-punched and calcined at high temperature to shape it into a fiber blanket. Example 2

[0020] A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃ comprises the following raw materials by weight percentage: SiO2: 76.93%, MgO: 18.59%, Al2O3: 2.80%, LiO2: 0.43%, SrO: 0.56%, CaO: 0.37%, Fe2O3: 0.17%, K2O: 0.15%; Its preparation method adopts the following steps: S1. Mix the above raw materials and add them to a resistance furnace for melting, controlling the temperature of the molten liquid to be 1890±10℃; S2. The molten liquid is poured into the spinning roller of the spinning machine through the outlet of the resistance furnace. The spinning speed of the spinning roller is controlled at 11,500 rpm. After being spun into fibers, the fibers are collected in the cotton collection box to form a continuous fiber felt. The fiber felt is then needle-punched and calcined at high temperature to shape it into a fiber blanket. Example 3

[0021] A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃ comprises the following raw materials by weight percentage: SiO2: 75.50%, MgO: 20.38%, Al2O3: 2.47%, LiO2: 0.42%, SrO: 0.42%, CaO: 0.44%, Fe2O3: 0.21%, K2O: 0.16%; Its preparation method adopts the following steps: S1. Mix the above raw materials and add them to a resistance furnace for melting, controlling the temperature of the molten liquid to be 1890±10℃; S2. The molten liquid is poured into the spinning roller of the spinning machine through the outlet of the resistance furnace. The spinning speed of the spinning roller is controlled at 11,500 rpm. After being spun into fibers, the fibers are collected in the cotton collection box to form a continuous fiber felt. The fiber felt is then needle-punched and calcined at high temperature to shape it into a fiber blanket. Example 4

[0022] A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃ comprises the following raw materials by weight percentage: SiO2: 75.03%, MgO: 20.06%, Al2O3: 1.50%, LiO2: 0.41%, SrO: 0.42%, CaO: 0.38%, Fe2O3: 0.14%, K2O: 0.06%; Its preparation method adopts the following steps: S1. Mix the above raw materials and add them to a resistance furnace for melting, controlling the temperature of the molten liquid to be 1890±10℃; S2. The molten liquid is poured into the spinning roller of the spinning machine through the outlet of the resistance furnace. The spinning speed of the spinning roller is controlled at 11,500 rpm. After being spun into fibers, the fibers are collected in the cotton collection box to form a continuous fiber felt. The fiber felt is then needle-punched and calcined at high temperature to shape it into a fiber blanket. Example 5

[0023] A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃ comprises the following raw materials by weight percentage: SiO2: 77.96%, MgO: 18.48%, Al2O3: 1.56%, LiO2: 0.57%, SrO: 0.78%, CaO: 0.40%, Fe2O3: 0.15%, K2O: 0.10%; Its preparation method adopts the following steps: S1. Mix the above raw materials and add them to a resistance furnace for melting, controlling the temperature of the molten liquid to be 1890±10℃; S2. The molten liquid is poured into the spinning roller of the spinning machine through the outlet of the resistance furnace. The spinning speed of the spinning roller is controlled at 11,500 rpm. After being spun into fibers, the fibers are collected in the cotton collection box to form a continuous fiber felt. The fiber felt is then needle-punched and calcined at high temperature to shape it into a fiber blanket. Comparative Example 1

[0024] A biosoluble ceramic fiber differs from Example 1 in the amount of raw materials used, specifically as follows: SiO2: 75.42%, MgO: 19.79%, Al2O3: 2.22%, LiO2: 0.43%, SrO: 0.47%, CaO: 1.45%, Fe2O3: 0.15%, K2O: 0.07%. Its preparation method is the same as that in Example 1. Comparative Example 2

[0025] A biosoluble ceramic fiber differs from Example 1 in the amount of raw materials used, specifically as follows: SiO2: 76.28%, MgO: 17.35%, Al2O3: 1.57%, LiO2: 0.42%, SrO: 0.54%, CaO: 3.57%, Fe2O3: 0.21%, K2O: 0.06%. Its preparation method is the same as that in Example 1. Comparative Example 3

[0026] A bio-soluble ceramic fiber, which is different from that of Example 1 in that the dosages of raw materials are different, specifically as follows: SiO2: 76.30%, MgO: 0.41%, Al2O3: 1.63%, LiO2: 0.43%, SrO: 0.52%, CaO: 20.53%, Fe2O3: 0.06%, K2O: 0.12%, and its preparation method is the same as that in Example 1. Comparative Example 4

[0027] A bio-soluble ceramic fiber, which is different from that of Example 1 in that the content of LiO2 exceeds the limit, and the dosages of each raw material are specifically as follows: SiO2: 76.08%, MgO: 19.11%, Al2O3: 2.56%, LiO2: 1.15%, SrO: 0.44%, CaO: 0.46%, Fe2O3: 0.14%, K2O: 0.06%, and its preparation method is the same as that in Example 1. Performance testing

[0028] The bulk density, slag ball content, tensile strength and high temperature resistance of the soluble ceramic fiber blankets obtained from the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0029] The tensile speed during the tensile strength test was 20 mm / min.

[0030] The high temperature resistance is to test the permanent linear shrinkage rate after burning the soluble ceramic fiber blanket at a specified temperature for 24 h. The test standard is GB / T17911-2006, and the permanent linear shrinkage rate less than 4% is qualified.

[0031] The slag ball content refers to the weight ratio of substances above 45 μm sieve holes.

[0032] Table 1 Performance test results of soluble ceramic fiber blankets project Thickness (mm) <![CDATA[Unit weight kg / m 3 > slag ball rate % Tensile strength (kPa) Permanent linear shrinkage rate at 1300℃ (%) Permanent linear shrinkage rate at 1350℃ (%) Example 1 24 127 38.8 65 1.89 3.53 Example 2 25 130 36.7 69 1.99 3.65 Example 3 24 128 38.7 72 1.93 3.72 Example 4 24 128 37.2 71 1.91 3.57 Example 5 25 130 36.4 70 1.95 3.62 Comparative Example 1 25 128 39.6 69 3.31 7.67 Comparative Example 2 25 130 32.0 67 6.73 / Comparative Example 3 26 133 36.1 84 2.87 11.83 Comparative Example 4 25 130 38.5 68 2.79 6.92 Note: " / " indicates not detected.

[0033] Combined with the test results in Table 1: The soluble ceramic fiber blankets obtained in Examples 1-5 of the present application have appropriate slag ball content and tensile strength, and at the same time, the permanent linear shrinkage rate is <4% after being treated at 1350 °C for 24 h, thus meeting the usage requirements in high temperature environments.

[0034] Compared with Example 1, when the amount of calcium oxide added was increased beyond the limits of this application, the permanent linear shrinkage rate of the soluble ceramic fiber blanket obtained in Comparative Example 1 after treatment at 1300°C for 24 hours was significantly increased, and the permanent linear shrinkage rate after treatment at 1350°C for 24 hours was much higher than 4%. The reason is that in silicate glass, calcium oxide does not form a skeleton like silicon dioxide, but rather cuts off the Si-O-Si connection, making the originally tight three-dimensional network structure loose. In addition, the addition of calcium oxide reduces the high-temperature viscosity of the glass melt. The reduction in viscosity means that the resistance to atomic rearrangement is reduced. At 1350°C, the fibers are more likely to undergo viscous flow, which leads to a sharp increase in linear shrinkage.

[0035] Compared with Example 1, Comparative Example 2 has a magnesium oxide content lower than the range defined in this application, while the calcium oxide content is further increased. The permanent linear shrinkage rate of the ceramic fiber after being treated at 1300°C for 24 hours is much higher than 4%, indicating that the glass network at 1300°C has begun to collapse or soften on a large scale, and the high temperature resistance of the ceramic fiber is already unqualified at 1300°C.

[0036] Compared with Example 1, Comparative Example 3, when the magnesium oxide content is extremely low relative to the impurity content and the calcium oxide content is >18%, after treatment at 1300°C for 24 hours, due to the extremely high calcium oxide content, it reacts with silicon dioxide and aluminum oxide to precipitate a large amount of anorthite and wollastonite crystals. These calcium crystals have a high melting point and good thermal stability, and the crystal growth rate may be very fast. The crystals precipitate rapidly at 1300°C, forming a dense crystal skeleton that firmly locks the fibers, thus giving the ceramic fibers obtained in Comparative Example 3 good high-temperature resistance at 1300°C. Although anorthite has a high melting point, due to the excessive calcium oxide content in the system, the remaining glassy phase is already extremely rich in calcium, resulting in a very low eutectic point. Therefore, as the processing temperature increases, the previously formed anorthite crystal framework may begin to undergo a crystal transformation and reintegrate into the glassy phase. As the crystal framework collapses, a large number of calcium and aluminum ions are released and enter the melt, causing the viscosity of the entire system to drop sharply and forming a large amount of liquid phase. This results in the linear shrinkage rate of ceramic fibers at 1350℃ being much higher than 4%.

[0037] Compared with Example 1, when the lithium oxide content exceeded the limit, the permanent linear shrinkage rate of the ceramic fiber at 1350°C was also higher than 4%. This is because when the lithium ion content is extremely low, it can enter the gaps in the network structure and play a certain repair role in the broken network. It can reduce the high-temperature viscosity and crystallization tendency of the glass melt, help the fiber maintain a uniform glassy state during molding, and promote the formation of fine and stable crystals at high temperatures, thereby helping to resist shrinkage at high temperatures. However, when the lithium content increases, the excess lithium cannot be accommodated by the network gaps. At this time, the free oxygen provided by lithium oxide begins to destroy the silicon-oxygen bonds on a large scale, which severely damages the originally strong three-dimensional network structure. Furthermore, due to the excessive addition of lithium oxide, the balance between lithium oxide and strontium oxide is broken, and the high concentration of lithium ions diffuses rapidly, accelerating the structural rearrangement and shrinkage at high temperatures, which significantly reduces the high-temperature resistance at 1350°C.

[0038] The embodiments described herein are merely illustrative of preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A biosoluble, high-temperature resistant ceramic fiber with a temperature range of 1350℃, characterized in that, The ceramic fiber comprises the following raw materials by weight percentage: SiO2: 75-78%, MgO: 18-23%, Al2O3: 1.5-2.8%, LiO2: 0.4-0.6%, SrO: 0.4-0.8%, with the balance being other metal oxides.

2. The 1350℃ biosoluble high-temperature resistant ceramic fiber according to claim 1, characterized in that: The ceramic fiber comprises the following raw materials by weight percentage: SiO2: 75-77%, MgO: 18-20%, Al2O3: 2.4-2.8%, LiO2: 0.4-0.5%, SrO: 0.4-0.6%, with the balance being other metal oxides.

3. A 1350℃ biosoluble high-temperature resistant ceramic fiber according to claim 1 or 2, characterized in that: The weight percentages of the other metal oxides are: CaO: 0.3-0.5%, Fe2O3: 0.1-0.3%, K2O: 0.05-0.20%.

4. A method for preparing 1350℃ biosoluble high-temperature resistant ceramic fibers as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Mix the above-mentioned raw materials and add them to the resistance furnace for melting; S2. After melting, the fibers are spun into fibers by a spinning roller. The fibers are collected to form a continuous fiber felt, which is then needle-punched and calcined at high temperature to shape it into a fiber blanket.

5. The method for preparing a 1350℃ biosoluble high-temperature resistant ceramic fiber according to claim 4, characterized in that: The melting temperature is 1850-2000℃.

6. The method for preparing a 1350℃ biosoluble high-temperature resistant ceramic fiber according to claim 4, characterized in that: The spinning speed of the spinning roller is 9500-11500 rpm.

7. The method for preparing a 1350℃ biosoluble high-temperature resistant ceramic fiber according to claim 4, characterized in that: The fiber blanket has a strength >50KPa, a slag ball ratio (>45μm) <48%, and a linear shrinkage rate <4% when heated at 1350℃ for 24h.