Sintered spherical mullite-zirconia composite high-temperature kiln lining material

Abstract

This invention discloses a sintered spherical mullite-zirconia composite high-temperature kiln lining material, belonging to the field of high-temperature resistant materials technology. It is prepared by sintering mesoporous spherical mullite particles as the matrix and zirconia hollow fibers as the reinforcing phase. This material belongs to advanced inorganic non-metallic materials and is a fireproof and heat-insulating special brick and tile material, suitable for use in energy-saving furnaces, high-temperature kilns, and other equipment. The combination of mesoporous spherical mullite particles and zirconia hollow fibers significantly increases the apparent porosity of the material, thereby reducing its bulk density and thermal conductivity; and the zirconia hollow fibers significantly enhance the material's strength.

Description

Technical Field

[0001] This invention relates to the field of high-temperature resistant materials technology, specifically to sintered spherical mullite-zirconia composite high-temperature kiln lining materials. Background Technology

[0002] High-temperature kilns are core equipment in industries such as metallurgy, building materials, ceramics, and chemicals. The performance of their lining materials directly determines the kiln's energy consumption, lifespan, and production efficiency. Mullite, due to its excellent high-temperature stability, creep resistance, and chemical corrosion resistance, is widely used in high-temperature kiln linings. However, traditional sintered mullite materials have two main drawbacks: first, their thermal shock resistance needs improvement, as they are prone to cracking and propagation under rapid heating and cooling conditions; second, they are inherently brittle, making them susceptible to structural damage under mechanical impact and material erosion.

[0003] In the existing technology, traditional mullite lining materials have the following drawbacks:

[0004] Structural defects: Conventional mullite is mostly non-porous or microporous, with poor thermal insulation performance (thermal conductivity ≥0.8W / (m•K)) and low density (bulk density ≤2g / cm³), making it susceptible to corrosion by high-temperature molten materials;

[0005] Insufficient thermal shock resistance: Pure mullite is brittle and can only withstand ≤15 cycles of thermal shock in a 1100℃ water cooling cycle. It is prone to cracking and peeling after long-term use.

[0006] Limitations of composite modification: Existing zirconia-modified mullite mostly uses zirconia powder as a dopant, which has poor powder dispersion and is prone to agglomeration, and cannot form a "fiber bridging" structure, resulting in limited improvement in mechanical strength and thermal shock resistance (room temperature compressive strength ≤90MPa); however, directly compositing zirconia hollow fibers with irregularly shaped mullite aggregates often results in uneven fiber dispersion and poor bonding strength with the matrix, leading to unsatisfactory reinforcement effects, and making it difficult to balance the bulk density and strength of the material.

[0007] Porous insulation materials are prone to shrinkage at high temperatures, making it difficult to maintain their original shape and size, which can lead to insulation structure failure.

[0008] The prior art CN117510191B discloses a corrosion-resistant furnace body material, its preparation method, and its application. This invention combines aluminum dihydrogen phosphate, hollow alumina spheres, and zirconium oxide microspheres to obtain a P2O5-Al2O3-ZrO2 composite at a high temperature of 1700℃. This invention utilizes the decomposition of magnesium carbonate powder at high temperature to generate MgO and CO2. MgO reacts with α-Al2O3 micropowder at high temperature to form a certain proportion of Al2O3·MgO spinel, exhibiting a high expansion and porous structure at high temperature, achieving low density and low thermal conductivity. However, the compressive strength of this material at room temperature is still insufficient, and the process makes it difficult to guarantee the stability of the material's performance.

[0009] Therefore, developing a composite lining material that can fully leverage the advantages of both mullite and zirconia fiber, and solve the problems of their interfacial bonding and uniform dispersion, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0010] In order to overcome the shortcomings of the existing technology, the present invention aims to solve the problems of poor thermal insulation, weak thermal shock resistance, low mechanical strength and high material density of existing high temperature kiln lining materials. The present invention provides a sintered spherical mullite-zirconia composite high temperature kiln lining material, which can achieve the technical effects of high thermal insulation, shock resistance, mechanical strength, light weight and suitability for industrial production.

[0011] This invention is achieved through the following technical solution: providing a sintered spherical mullite-zirconia composite high-temperature kiln lining material, which is prepared by sintering with mesoporous spherical mullite particles as the matrix and zirconia hollow fibers as the reinforcing phase. The amount of zirconia hollow fibers is 10%-20% of the mass of the mesoporous spherical mullite.

[0012] The mesoporous spherical mullite has a particle size range of 1μm-2μm, preferably 1.5μm-1.7μm, and an internal mesoporous pore size distribution of 10nm-25nm. This mesoporous structure not only reduces the thermal conductivity of the material but also provides space for stress release during the sintering process. Its spherical morphology ensures the material has the highest packing density and more uniform physical properties, while the mesoporous structure reduces the bulk density of the material.

[0013] Zirconia hollow fiber: diameter 6-10μm, length 200μm, purity: ZrO2:Y2O3=90%:10%, dosage is 10%-20% of the mass of mesoporous spherical mullite particles, preferably 15%-20%.

[0014] The method for preparing the mesoporous spherical mullite is as follows:

[0015] Step 1: Sol preparation: According to the stoichiometric ratio of mullite (Al2O3•2SiO2), aluminum nitrate (Al(NO3)3) and tetraethyl orthosilicate (TEOS) are dissolved in an ethanol-water mixed solvent (volume ratio 1:(1~2)). A template agent is added, the amount of which is 3-8% of the total mass of aluminum nitrate and tetraethyl orthosilicate. After stirring for 5-10 min, ammonia water is added dropwise to adjust the pH to 7.5-8.0 to form a transparent sol.

[0016] The template agent is selected from: P123 and F127.

[0017] Step 2: Granulation. Pass the sol through a spray granulator (0.5mm nozzle, 0.6MPa pressure, 80℃ outlet temperature, 1-1.2m / s) and fluidize and dry for 10-20 minutes, then collect the granules.

[0018] Step 3: Mesoporous formation: The collected particles are vacuum dried at 80℃ for 12h, and then heated to 500-700℃ in a muffle furnace at a heating rate of 5℃ / min and held for 2-3h to remove the template agent and form a mesoporous structure, thus obtaining mesoporous spherical mullite (powder, mesoporous pore size 10-25nm, preferably 15-25nm, 18-25nm, 20-25nm).

[0019] The preparation method of the sintered spherical mullite-zirconia composite high-temperature kiln lining material is as follows:

[0020] S1: Pretreatment of Zirconia Hollow Fibers

[0021] Zirconia hollow fibers were immersed in a 5wt% nitric acid solution and ultrasonically treated at 60℃ for 20-40 min to remove surface impurities and introduce hydroxyl groups. They were then washed with deionized water until neutral and dried at 100℃-120℃ for 1-4 h to obtain dispersibility-modified zirconia hollow fibers.

[0022] S2: Composite molding and sintering

[0023] Mixing and formulation: Mix mesoporous spherical mullite powder with pretreated zirconia hollow fibers in a certain amount, add 1-2 wt% polyvinyl alcohol (PVA) binder, and ball mill in a planetary ball mill at 150-300 r / min for 0.5 h-1 h to obtain a uniform composite powder;

[0024] Compression molding: The composite powder is loaded into a mold and pressed into a blank on a hydraulic press under a pressure of 20-30MPa;

[0025] High-temperature sintering: The green body is placed in a high-temperature sintering furnace and heated to 1550-1650℃ at a heating rate of 3℃ / min. It is held at this temperature for 4-6 hours and then cooled to room temperature with the furnace to obtain sintered spherical mullite-zirconia composite high-temperature kiln lining material.

[0026] Beneficial effects

[0027] This invention provides a sintered spherical mullite-zirconia composite high-temperature kiln lining material, which is prepared by sintering using mesoporous spherical mullite particles as the matrix and zirconia hollow fibers as the reinforcing phase. By combining mesoporous spherical mullite particles with zirconia hollow fibers, the apparent porosity of the material is greatly increased, thereby reducing the material's bulk density and thermal conductivity.

[0028] Significantly improved thermal insulation performance: The 10-25nm mesoporous structure of the mesoporous spherical mullite significantly reduces the thermal conductivity, with a room temperature thermal conductivity ≤0.4W / (m•K). Simultaneously, the low-density zirconia hollow fibers further reduce the overall density of the material, resulting in a lightweight advantage. Significantly enhanced thermal shock resistance: The zirconia hollow fibers form a "bridging network" within the material, withstanding ≥35 thermal shock cycles under 1100℃ water cooling. Optimized mechanical strength: The fiber-mullite interface is tightly bonded, achieving a room temperature compressive strength ≥110MPa and a high-temperature (1500℃) flexural strength ≥26.1MPa. Good process economy: The spray granulation process is easily industrialized, and the particle size of the prepared mesoporous spherical mullite particles is relatively controllable and uniform, reducing batch-to-batch variations and ensuring product quality. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The described embodiments are only some preferred embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise specified, the experimental methods used in the embodiments are conventional or common methods in the art, and the materials and reagents used are commercially available unless otherwise specified.

[0031] The raw materials used in the examples and comparative examples are described below:

[0032] Zirconia hollow fiber: Forsmann, specifications Φ: 6-10μm, L: 200μm, purity ZrO2:Y2O3=90%:10%.

[0033] Zirconia fiber: Forsmann, specifications Φ: 3-5μm, L: 200μm.

[0034] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0035] Preparation Example 1

[0036] Preparation of mesoporous spherical mullite:

[0037] Step 1: Sol preparation. Aluminum nitrate (Al(NO3)3) and tetraethyl orthosilicate (TEOS) were dissolved in an ethanol-water mixture (volume ratio 1:1.5) at a stoichiometric ratio of 1:10 (g / mL). Template agent P123 was added at 4% of the total mass of aluminum nitrate and tetraethyl orthosilicate. After stirring at 800 rpm for 10 min, ammonia was added dropwise to adjust the pH to 7.5, forming a transparent sol.

[0038] Step 2: Granulation. Pass the sol through a spray granulator (0.5mm nozzle, 0.6MPa pressure, 80℃ outlet temperature, 1-1.2m / s) and fluidize and dry for 10 minutes, then collect the granules.

[0039] Step 3: Mesoporous Formation. The collected particles were vacuum dried at 80℃ for 12h, and then heated to 600℃ in a muffle furnace at a heating rate of 5℃ / min and held for 3h to remove the template agent and form a mesoporous structure, obtaining mesoporous spherical mullite 1 (powder).

[0040] Preparation Examples 2-3

[0041] Preparation Examples 2-3 are the same as Preparation Example 1, except that the amount of template agent P123 is adjusted.

[0042] Preparation Examples 4-5

[0043] Preparation Examples 4-5 are the same as Preparation Example 1, except that the template agent P123 is replaced with F127 and the dosage is adjusted.

[0044] Comparative Preparation Example 1

[0045] Comparative Preparation Example 1 is the same as Preparation Example 1, except that the template agent P123 is replaced with hexadecyltrimethylammonium bromide (CTAB).

[0046] Comparative Preparation Example 2

[0047] Preparation Example 2 was the same as Preparation Example 1, except that no template agent was added.

[0048] Comparative preparation examples 3-4 are the same as preparation example 1, except that the heating temperature of the muffle furnace is adjusted to 400℃ or 900℃, while other parameters remain unchanged.

[0049] Table 1 Comparison of process parameter changes between the preparation example and the control preparation example

[0050]

[0051] Example 1

[0052] A method for preparing sintered spherical mullite-zirconia composite high-temperature kiln lining material.

[0053] S1: Pretreatment of Zirconia Hollow Fibers

[0054] Zirconia hollow fibers were immersed in a 5 wt% nitric acid solution and ultrasonically treated at 60°C for 30 min to remove surface impurities and introduce hydroxyl groups. They were then washed with deionized water until neutral and dried at 120°C for 2 h to obtain dispersibility-modified zirconia hollow fibers.

[0055] S2: Composite molding and sintering

[0056] Mixing and formulation: Mesoporous spherical mullite 1 and pretreated zirconia hollow fibers are mixed in a certain amount, and 2wt% polyvinyl alcohol (PVA) binder is added. The mixture is then ball-milled in a planetary ball mill at 200r / min for 1h to obtain a uniform composite powder.

[0057] Compression molding: The composite powder is loaded into a mold and pressed into a blank on a hydraulic press with a pressure of 25MPa; High-temperature sintering: The blank is placed in a high-temperature sintering furnace and heated to 1600℃ at a heating rate of 3℃ / min, held for 6h, and cooled to room temperature with the furnace to obtain sintered spherical mullite-zirconia composite high-temperature kiln lining material.

[0058] Example 2-3

[0059] Examples 2-3 were prepared using the same method as Example 1, except that the amount of zirconium hollow fiber was adjusted.

[0060] Examples 4-7

[0061] Examples 4-7 were prepared using the same method as Example 1, except that the mesoporous spherical mullite 1 was replaced with mesoporous spherical mullite 2, mesoporous spherical mullite 3, mesoporous spherical mullite 4, and mesoporous spherical mullite 5, respectively. Furthermore, the sintering temperatures in Examples 6 and 7 were adjusted to 1550℃ or 1650℃, respectively.

[0062] Comparative Examples 1-2

[0063] Comparative Examples 1-2 were prepared using the same method as Example 1, except that the amount of mesoporous spherical mullite 1 was adjusted.

[0064] Comparative Examples 3-6

[0065] Comparative Examples 3-6 were prepared using the same method as Example 1, except that the mesoporous spherical mullite 1 was replaced with mesoporous spherical mullite 6, mesoporous spherical mullite 7, mesoporous spherical mullite 8, and mesoporous spherical mullite 9, respectively.

[0066] Comparative Example 7

[0067] Comparative Example 7 was prepared using the same method as Example 1, except that the zirconia hollow fibers were replaced with zirconia fibers.

[0068] Comparative Example 8

[0069] Comparative Example 8 was prepared using the same method as Example 1, except that the 5% nitric acid solution in step S1 was replaced with an equal volume of deionized water.

[0070] Comparative Example 9

[0071] Comparative Example 9 was prepared using the same method as Example 1, except that no binder was added in step S2.

[0072] Table 2 Comparison of preparation methods in the examples and comparative examples

[0073]

[0074] Performance testing

[0075] 1. Determination of grain size and mesopore size of mesoporous mullite

[0076] Table 3. Particle size (μm) and mesoporous range (nm) of mesoporous spherical mullite 1-9

[0077]

[0078] According to the data in Table 3, 1) the difference in the preparation methods of mesoporous spherical mullite 1-3 lies in the amount of template agent P123 used, which is 4%, 3%, and 5% of the total mass of aluminum nitrate and tetraethyl orthosilicate, respectively. That is, the amount of template agent P123 is different, and the mesoporous pore size of the resulting mesoporous spherical mullite is positively correlated with the amount of template agent. However, when the amount of template agent P123 is 4% of the total mass of aluminum nitrate and tetraethyl orthosilicate, the particle size uniformity (PDI) is better. Mesoporous spherical mullite with uniform particle size is more conducive to the mixing with zirconium hollow fibers. 2) Compared with mesoporous spherical mullite 1, based on the particle size and mesoporous pore size range, template agents F127 and P123 can achieve similar technical effects. 3) Compared to mesoporous spherical mullite 1, mesoporous spherical mullite 6 exhibits a significantly smaller mesopore size range. This suggests that hexadecyltrimethylammonium bromide (CTAB) forms smaller mesopores compared to the template agent P123, which may explain the increased material density and thermal conductivity. 4) Since no template agent was added during the preparation of spherical mullite 7, it lacks a mesoporous structure. 5) Due to the relatively low sintering temperature of 400℃ during the preparation of mesoporous spherical mullite 8, grain growth was insufficient. Grain growth involves the chemical reaction and shrinkage of the raw materials. Therefore, the insufficient overall shrinkage of the mesoporous spherical mullite 8 (particles) after sintering resulted in a larger particle size compared to mesoporous spherical mullite 1. Furthermore, the insufficient expansion of the mesopores on the particles during sintering led to a smaller mesopore size. Due to the sintering temperature being set to 900℃ during the preparation process, the grains of the mesoporous spherical mullite 9 were overgrown. As a result, the overall size of the mesoporous spherical mullite 9 (particles) after sintering was too large, resulting in a smaller particle size compared to the mesoporous spherical mullite 1. Furthermore, the mesoporous pore size was also smaller due to the over-sintering.

[0079] 2. Tests for bulk density, compressive strength, high-temperature flexural strength, thermal conductivity, and thermal shock resistance.

[0080] Bulk density: Tested according to GB / T2997-2015 "Bulk density, apparent porosity and true porosity of dense shaped refractory products" (water displacement method);

[0081] Room temperature compressive strength: Tested according to GB / T5072-2008 "Test Method for Room Temperature Compressive Strength of Refractory Materials";

[0082] High-temperature flexural strength: Tested according to GB / T3002-2017 "Test Method for High-Temperature Flexural Strength of Refractory Materials" (1500℃);

[0083] Thermal conductivity: Tested according to GB / T10294-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - protective hot plate method" (room temperature);

[0084] Thermal shock resistance: According to GB / T30873-2014 "Test method for thermal shock resistance of refractory materials - water quenching method", the material was kept at 1100℃ for 30 minutes and then water-cooled. The number of cycles before cracking was recorded.

[0085] Table 4 Performance Test Results

[0086]

[0087] According to the data in Table 4, the sintered spherical mullite-zirconia composite high-temperature kiln lining materials prepared in Examples 1-7 have a strength of 1.02-1.18 g / cm³. 3The bulk density ranges from 114 to 120 MPa, the room temperature compressive strength ranges from 0.33 to 0.38 W / (m•K), and the number of thermal shocks at 1100℃ ranges from 36 to 40. 1) Compared with Example 1, Comparative Example 1 reduced the amount of zirconia hollow fiber, resulting in a significant decrease in room temperature compressive strength and flexural strength at 1500℃. This indicates that zirconia hollow fiber can improve the strength of the composite high-temperature kiln lining material. The number of thermal shock cycles at 1100℃ decreased to 21, which also indicates that zirconia hollow fiber forms a three-dimensional network in the composite high-temperature kiln lining material, improving strength and thermal shock resistance through phase transformation toughening. Compared with Example 1, Comparative Example 2 increased the amount of zirconia hollow fiber. However, the room temperature compressive strength and flexural strength at 1500℃ did not improve but instead decreased slightly. This may be related to the difficulty in mixing a large amount of zirconia hollow fiber with mesoporous spherical mullite. Some zirconia hollow fiber agglomerates, resulting in a relatively uneven internal composition of the composite high-temperature kiln lining material, which affects the strength. 2) In Comparative Example 3, compared to Example 1, mesoporous spherical mullite 1 was replaced with mesoporous spherical mullite 6. Because the particle size and mesoporous range of mesoporous spherical mullite 6 are smaller, it is easier to compact during the preparation of composite high-temperature kiln lining materials, thus reducing apparent porosity and resulting in increased bulk density and room-temperature thermal conductivity. 3) In Comparative Example 4, compared to Example 1, mesoporous spherical mullite 1 was replaced with spherical mullite 7. Because spherical mullite 7 has a smaller particle size, the composite high-temperature kiln lining material prepared using it has even lower apparent porosity, resulting in a significant increase in bulk density and room-temperature thermal conductivity. 4) In Comparative Example 5, compared to Example 1, mesoporous spherical mullite 1 was replaced with mesoporous spherical mullite 8. Because the sintering temperature (400°C) of mesoporous spherical mullite 8 during preparation was relatively low, the prepared mesoporous spherical mullite 8 was not fully sintered, resulting in low structural strength. Therefore, when preparing composite high-temperature kiln lining materials, the structure of the mesoporous spherical mullite 8 may collapse due to compression, leading to low apparent porosity, thus increasing the bulk density and room-temperature thermal conductivity. However, in Comparative Example 6, the mesoporous spherical mullite 9, due to its higher sintering temperature (800°C), resulted in smaller particle size. Consequently, the mesoporous spherical mullite 8 was more easily compressed and compacted, leading to low apparent porosity, thus increasing the bulk density and room-temperature thermal conductivity. 5) In Comparative Example 7, the hollow zirconia fiber was replaced with zirconia fiber (non-hollow structure) because the zirconia fiber does not have a hollow structure and has a higher density, which leads to a significant increase in bulk density and room temperature thermal conductivity.6) Compared to Example 1, in Comparative Example 8, when preparing the composite high-temperature kiln lining material, the 5% nitric acid solution in step S1 was replaced with an equal volume of deionized water. This resulted in the lack of hydroxyl groups in the zirconia hollow fibers, reducing the bonding strength with the mesoporous spherical mullite, and consequently leading to a significant decrease in bulk compressive strength at room temperature, flexural strength at 1500℃, and thermal shock resistance at 1100℃. 7) Compared to Example 1, in Comparative Example 9, when preparing the composite high-temperature kiln lining material, no binder was added in step S2, resulting in a decrease in thermal shock resistance, mechanical strength, and other properties. It is evident that the binder can ensure that the zirconia hollow fiber reinforcing phase exists uniformly and stably in the mullite matrix and forms a strong interfacial bond with it, thereby jointly achieving the material's comprehensive excellent performance of high thermal shock resistance, high mechanical strength, and low thermal conductivity.

[0088] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A sintered spherical mullite-zirconia composite high-temperature kiln lining material, characterized in that, The mullite is prepared by sintering using mesoporous spherical mullite particles as the matrix and zirconia hollow fibers as the reinforcing phase. The amount of zirconia hollow fibers is 10%-20% of the mass of the mesoporous spherical mullite. The zirconia hollow fibers have a diameter of 6-10 μm, a length of 200 μm, and a purity of ZrO2:Y2O3 = 90 wt%:10 wt%. The mesoporous spherical mullite has a particle size range of 1 μm-2 μm and an internal mesoporous pore size distribution of 10 nm-25 nm. The preparation method of the mesoporous spherical mullite is as follows: Step 1: Sol preparation: According to the stoichiometric ratio of mullite Al2O3•2SiO2, aluminum nitrate (Al(NO3)3) and tetraethyl orthosilicate are dissolved in an ethanol-water mixed solvent with a volume ratio of ethanol to water of 1:(1-2). A template agent is added, with an amount of 3-8% of the total mass of aluminum nitrate and tetraethyl orthosilicate. After stirring for 5-10 minutes, ammonia water is added dropwise to adjust the pH to 7.5-8.0 to form a transparent sol. Step 2: Granulation: Spray the sol into granules using a spray granulator, fluidize and dry for 10-20 minutes, and collect the granules; Step 3: Mesoporous forming: The collected particles are vacuum dried at 60-80℃ for 10-12h, and then heated to 500-700℃ in a muffle furnace at a heating rate of 5℃ / min and held for 2-3h to obtain mesoporous spherical mullite.

2. The sintered spherical mullite-zirconia composite high-temperature kiln lining material according to claim 1, characterized in that, The mesoporous spherical mullite has a particle size range of 1.5μm-1.7μm and an internal mesoporous pore size distribution of 15-25nm, 18-25nm or 20-25nm.

3. The sintered spherical mullite-zirconia composite high-temperature kiln lining material according to claim 1, characterized in that, The template agent mentioned in step 1 is selected from: P123 and F127.

4. The method for preparing sintered spherical mullite-zirconia composite high-temperature kiln lining material according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Pretreatment of zirconium oxide hollow fibers; S2: Composite molding and sintering.

5. The method for preparing sintered spherical mullite-zirconia composite high-temperature kiln lining material according to claim 4, characterized in that, Step S1: The specific method for pretreatment of zirconium oxide hollow fibers is as follows: Zirconia hollow fibers were immersed in a 5wt% nitric acid solution and ultrasonically treated at 60℃ for 20-40 min to remove surface impurities and introduce hydroxyl groups. They were then washed with deionized water until neutral and dried at 100℃-120℃ for 1-4 h to obtain dispersibility-modified zirconia hollow fibers.

6. The method for preparing sintered spherical mullite-zirconia composite high-temperature kiln lining material according to claim 4, characterized in that, Step S2: The specific methods for composite molding and sintering are as follows: Mixing and formulation: Mix mesoporous spherical mullite powder with pretreated zirconia hollow fibers in a certain amount, add 1-2 wt% polyvinyl alcohol (PVA) binder, and ball mill in a planetary ball mill at 150-300 r / min for 0.5 h-1 h to obtain a uniform composite powder; Compression molding: The composite powder is loaded into a mold and pressed into a blank on a hydraulic press under a pressure of 20-30MPa; High-temperature sintering: The green body is placed in a high-temperature sintering furnace and heated to 1550-1650℃ at a heating rate of 3℃ / min. It is held at this temperature for 4-6 hours and then cooled to room temperature with the furnace to obtain sintered spherical mullite-zirconia composite high-temperature kiln lining material.

Images