A hollow alumina silicate ceramic fiber and a method of making the same
By using natural kapok fiber as a template to prepare hollow aluminosilicate ceramic fiber, the problem of insufficient thermal insulation performance of solid aluminosilicate fiber is solved, achieving a lower thermal conductivity and better thermal insulation effect, and the process is simple and environmentally friendly.
Patent Information
- Application Number
- CN202510004292.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2026-07-03
AI Technical Summary
The aluminum silicate fibers prepared by existing methods have a solid structure, which limits the further improvement of their thermal insulation performance, and the traditional methods are not environmentally friendly.
Hollow aluminosilicate ceramic fibers were prepared by using natural kapok fibers as templates and a residual method. By combining the low thermal conductivity of aluminosilicate materials with the hollow structure of natural fibers, hollow aluminosilicate ceramic fibers with excellent thermal insulation properties were prepared.
The hollow structure restricts heat transfer, improves insulation, has a lower thermal conductivity, provides better heat preservation, and is simple to operate and environmentally friendly.
Smart Images
Figure CN122327412A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of thermal insulation ceramic fibers, and relates to a hollow aluminosilicate ceramic fiber and its preparation method. Background Technology
[0002] Alumina silicate materials, as important thermal insulation and refractory materials in high-temperature industries, play a crucial role in energy conservation, emission reduction, and green production. Thermal insulation alumina silicate materials are not only core foundation materials for high-temperature equipment, but their research and technological advancements are also closely related to the green development of high-temperature industries. Therefore, technological innovation in alumina silicate materials is indispensable for promoting the development of high-temperature industries. Thermal insulation alumina silicate ceramics mainly include two categories: oxides and non-oxides. The former, primarily composed of Al₂O₃ and SiO₂, is resistant to high temperatures and corrosion, possesses low thermal conductivity, and is an important refractory material.
[0003] Currently, there are various methods for preparing aluminosilicate fibers, such as melt spinning, sol-gel spinning, and electrospinning. However, aluminosilicate fibers prepared by traditional methods are all solid structures, which is not conducive to further improving their thermal insulation properties. Observation has revealed that there are many plant and animal fibers in nature with excellent thermal insulation properties, such as milkweed, kapok, reeds, and cattails. The microstructure of these fibers is hollow tubular. Because the hollow structure is not conducive to heat transfer, these fibers have excellent thermal insulation properties. Summary of the Invention
[0004] The purpose of this invention is to provide a hollow aluminosilicate ceramic fiber and its preparation method. The method uses natural kapok fiber as a template and adopts a residual state method to prepare hollow aluminosilicate fibers that can preserve the original morphology of natural kapok fibers. Combined with the low thermal conductivity of aluminosilicate materials, hollow aluminosilicate ceramic fibers with excellent thermal insulation properties are prepared.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] In a first aspect, the present invention provides a method for preparing hollow aluminosilicate ceramic fibers, comprising the following steps:
[0007] (1) Preparation of impregnation solution:
[0008] In an anhydrous ethanol solution of Al(NO3)3, according to the aluminum-silicon molar ratio n(Al 3+ ):n(Si 4+ Add tetraethyl orthosilicate at a ratio of 1.8:1, stir evenly, and the precursor impregnation solution is obtained;
[0009] (2) Preparation of precursor fibers:
[0010] Clean kapok fibers are immersed in a precursor impregnation solution, removed and squeezed to remove excess solution, and then vacuum dried to obtain precursor fibers.
[0011] (3) Preparation of hollow aluminosilicate ceramic fibers:
[0012] The precursor fibers are placed in a muffle furnace and heated to 1100–1300°C, and held for 1.5–2 hours to obtain hollow aluminosilicate ceramic fibers.
[0013] Preferably, in step (1), the concentration of aluminum nitrate in the precursor impregnation solution is 6 wt%.
[0014] Preferably, in step (2), clean kapok fibers refer to those that have been washed three times.
[0015] Preferably, in step (2), the soaking time is 1.5 to 2 hours; the vacuum drying temperature is 60°C and the drying time is 12 hours.
[0016] Preferably, in step (3), the sintering temperature is 1300℃, the holding time is 1.5h, and the heating rate during the sintering process is 5℃ / min.
[0017] Preferably, in step (3), the annealing temperature is 1100℃ and the holding time is 3 to 5 hours.
[0018] In a second aspect, the present invention provides hollow aluminosilicate ceramic fibers prepared by the method described in the first aspect.
[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0020] 1. Using kapok fiber as a template, the hollow structure of the natural fiber is preserved.
[0021] 2. Compared with solid aluminum silicate fiber, it has a unique hollow structure. The hollow structure can restrict air flow and reduce convective and radiative heat transfer, thereby improving the heat insulation effect. It also has a lower thermal conductivity and better heat preservation effect.
[0022] 3. Simple operation and easy to repeat. This invention has low cost, readily available template materials, and a simple preparation process.
[0023] 4. Green and environmentally friendly, making it more friendly to the environment. Attached Figure Description
[0024] Figure 1 This is a high-magnification SEM image of the morphology of natural hollow fiber kapok.
[0025] Figure 2 This is a low-magnification SEM image of the morphology of natural hollow fiber kapok.
[0026] Figure 3This is a microscopic morphology image of the hollow aluminum silicate fiber obtained in Example 1.
[0027] Figure 4 This is the XRD pattern of the hollow aluminum silicate fiber obtained in Example 1.
[0028] Figure 5 The value is the thermal conductivity of the hollow aluminum silicate fiber obtained in Example 1.
[0029] Figure 6 This is the XRD pattern of the hollow aluminum silicate fiber obtained in Example 2.
[0030] Figure 7 This is a microscopic morphology image of the hollow aluminum silicate fiber obtained in Example 2.
[0031] Figure 8 This is the XRD pattern of the hollow aluminum silicate fiber obtained in Example 3.
[0032] Figure 9 This is a microscopic morphology image of the hollow aluminum silicate fiber obtained in Example 3.
[0033] Figure 10 This is the XRD pattern of the hollow aluminum silicate fiber obtained in Example 4.
[0034] Figure 11 This is a microscopic morphology image of the hollow aluminum silicate fiber obtained in Example 4. Detailed Implementation
[0035] The present application will be further described below with reference to specific embodiments.
[0036] It should be noted that terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of this application.
[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.
[0038] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0039] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.
[0040] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.
[0041] Concentration, amount, and other numerical data may be presented in range format herein. It should be understood that such range format is used solely for convenience and brevity and should be flexibly interpreted to include not only the values explicitly stated as the limits of the range, but also all individual values or subranges encompassed within the range, as if each value and subrange were explicitly stated. For example, a range of values from about 1 to about 4.5 should be interpreted to include not only the explicitly stated limits of 1 to 4.5, but also individual numbers (such as 2, 3, 4) and subranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that describe only a single value, such as “less than about 4.5,” which should be interpreted to include all the aforementioned values and ranges. Furthermore, this interpretation should apply regardless of the breadth of the range or characteristic described.
[0042] To clean the natural hollow fiber kapok, a preliminary treatment is performed: the natural fiber kapok is washed with water three times. Figure 1 This is a high-magnification microscopic image of kapok fiber. As can be seen from the image, the fiber is smooth and flat under a microscopic scale, exhibiting a hollow structure. Figure 2 This is a low-magnification SEM image of the morphology of natural hollow fiber kapok, which is generally flat.
[0043] Example 1
[0044] Preparation of hollow aluminosilicate ceramic fibers (n(Al) 3+ ):n(Si 4+ The method with a ratio of 1.8:1 is as follows:
[0045] (1) Dissolve 111.936g of aluminum nitrate nonahydrate and 34.536g of tetraethyl orthosilicate in 1.2L of ethanol to prepare an impregnation solution with an aluminum nitrate concentration of 6wt%.
[0046] (2) The pre-treated kapok fibers were immersed in the impregnation solution for 2 hours, then removed and squeezed to remove excess solution. They were then dried in a vacuum drying oven (to prevent uneven shrinkage and cracking during the sintering process). The drying temperature was 60℃ and the drying time was 12 hours to obtain the precursor fibers.
[0047] (3) The precursor fiber was placed in a muffle furnace and sintered to 1300℃ at a heating rate of 5℃ / min. After holding for 2 hours, it was cooled with the furnace to obtain hollow aluminosilicate ceramic fiber.
[0048] from Figure 3 It can be seen that the hollow aluminosilicate ceramic fibers prepared in Example 1 have well inherited the hollow structure.
[0049] from Figure 4 As can be seen, the aluminum silicate crystalline phase was successfully synthesized in Example 1.
[0050] from Figure 5 It can be seen that the thermal conductivity of the hollow aluminosilicate ceramic fiber prepared in Example 1 is significantly improved compared with that of the solid aluminosilicate fiber.
[0051] Example 2
[0052] Preparation of hollow aluminosilicate ceramic fibers (n(Al) 3+ ):n(Si 4+ The method with a ratio of 2:1 is as follows:
[0053] (1) Dissolve 111.936g of aluminum nitrate nonahydrate and 31.08g of tetraethyl orthosilicate in 1.2L of ethanol to prepare an impregnation solution with an aluminum nitrate concentration of 6wt%.
[0054] (2) The remaining steps are the same as in Example 1.
[0055] from Figure 6 It can be seen that the hollow aluminosilicate ceramic fiber prepared in Example 2 contains an alumina impurity phase.
[0056] from Figure 7 It can be seen that the hollow aluminosilicate ceramic fiber prepared in Example 2 inherits the hollow structure very well, but the fiber wall has obvious defects.
[0057] Example 3
[0058] Preparation of hollow aluminosilicate ceramic fibers (n(Al) 3+ ):n(Si 4+ The method with a ratio of 1.9:1 is as follows:
[0059] (1) Dissolve 111.936g of aluminum nitrate nonahydrate and 32.716g of tetraethyl orthosilicate in 1.2L of ethanol to prepare an impregnation solution with an aluminum nitrate concentration of 6wt%.
[0060] (2) The remaining steps are the same as in Example 1.
[0061] from Figure 8 It can be seen that the hollow aluminosilicate ceramic fibers prepared in Example 3 contain an alumina impurity phase.
[0062] from Figure 9 It can be seen that the hollow aluminosilicate ceramic fiber prepared in Example 3 inherits the hollow structure very well, but the fiber wall has obvious defects.
[0063] Example 4
[0064] The method for preparing hollow aluminosilicate ceramic fibers (sintering temperature 1200℃) is as follows:
[0065] (1) Dissolve 111.936g of aluminum nitrate nonahydrate and 34.536g of tetraethyl orthosilicate in 1.2L of ethanol to prepare an impregnation solution with an aluminum nitrate concentration of 6wt%.
[0066] (2) The pre-treated kapok fibers were immersed in the impregnation solution for 2 hours, then removed and squeezed to remove excess solution. Subsequently, they were dried in a vacuum drying oven at a temperature of 60°C for 12 hours to obtain precursor fibers.
[0067] (3) The precursor fiber was placed in a muffle furnace and sintered to 1200℃ at a heating rate of 5℃ / min. After holding for 2 hours, it was cooled with the furnace to obtain hollow aluminosilicate ceramic fiber.
[0068] from Figure 10 It can be seen that the hollow aluminosilicate ceramic fiber prepared in Example 4 contains an alumina impurity phase.
[0069] from Figure 11 It can be seen that the hollow aluminosilicate ceramic fiber prepared in Example 4 inherits the hollow structure very well, but the fiber wall has obvious defects.
[0070] The above embodiments are merely preferred embodiments of the present invention, but the implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, or combinations made without departing from the spirit and principle of the present invention, such as various combinations of solutions in the embodiments, should be considered equivalent replacements and are all within the protection scope of the present invention.
Claims
1. A method for preparing hollow aluminosilicate ceramic fibers, characterized in that, Including the following steps: (1) Preparation of impregnation solution: In an anhydrous ethanol solution of Al(NO3)3, according to the aluminum-silicon molar ratio n(Al 3+ ):n(Si 4+ Add tetraethyl orthosilicate at a ratio of 1.8:1, stir evenly, and the precursor impregnation solution is obtained; (2) Preparation of precursor fibers: Clean kapok fibers are immersed in a precursor impregnation solution, removed and squeezed to remove excess solution, and then vacuum dried to obtain precursor fibers. (3) Preparation of hollow aluminosilicate ceramic fibers: The precursor fibers are placed in a muffle furnace and heated to 1100~1300 ℃, and held for 1.5~2 hours to obtain hollow aluminosilicate ceramic fibers.
2. The method as described in claim 1, characterized in that, The concentration of aluminum nitrate in the precursor impregnation solution was 6 wt%.
3. The method as described in claim 1, characterized in that, Clean kapok fibers refer to those that have been washed three times.
4. The method as described in claim 1, characterized in that, In step (2), soak for 1.5 to 2 hours.
5. The method as described in claim 1, characterized in that, In step (2), the vacuum drying temperature is 60 °C and the drying time is 12 h.
6. The method as described in claim 1, characterized in that, In step (3), the sintering temperature is 1300 ℃, the holding time is 1.5 h, and the heating rate during the sintering process is 5 ℃ / min.
7. The method as described in claim 1, characterized in that, In step (3), the annealing temperature is 1100℃ and the holding time is 3~5h.
8. A hollow aluminosilicate ceramic fiber prepared by the method according to any one of claims 1-7.