Aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers, and its preparation method and application

Abstract

The present invention provides an aluminum oxide-silicon carbide-carbon unburned refractory material reinforced with carbon silicide aluminum whiskers, and a preparation method and application thereof, belonging to the technical field of refractory materials. The present invention controls the composition of the unburned refractory material and the amount of each component used. Silicon powder, aluminum powder and graphite powder are used as raw materials for Al4SiC4 whiskers. Under the action of a catalyst, during high-temperature use, Al4SiC4 whiskers grow in situ in the refractory material. Compared with one-dimensional granular Al4SiC4, Al4SiC4 whiskers have a two-dimensional linear structure and a larger surface area. They have better wrapping properties inside the unburned refractory material, are preferentially oxidized during oxidation, and have a better protection effect on other easily oxidized substances inside the unburned refractory material during the oxidation process. Al4SiC4 whiskers also have the characteristics of whiskers themselves, which can not only improve the oxidation resistance of the unburned refractory material, but also enhance the mechanical properties of the unburned refractory material.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory materials, and in particular to an aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers, and a preparation method and application thereof. Background Art

[0002] Refractory materials are in high demand as base materials for high-temperature industries, but the production process of refractory materials consumes a large amount of mineral resources and energy. Compared with fired refractory products, unfired refractory materials can be used directly after baking without firing. They are sintered under high temperature conditions, and the phase composition changes, re-forming new phases to obtain high-temperature performance. The use of unfired refractory materials greatly reduces the consumption of energy and resources. Carbon-containing composite unfired refractory materials have excellent thermal shock resistance and slag erosion resistance, and are widely used in converters, electric furnaces, refining furnace linings, and ladle slag lines. However, the problems of poor oxidation resistance and high-temperature mechanical properties of carbon-containing composite unfired refractory materials need to be urgently addressed.

[0003] The ternary carbide Al4SiC4 has a hexagonal crystal structure similar to SiC, and has high strength, high melting point (about 2037°C), high chemical stability, low density, low thermal expansion coefficient and excellent antioxidant properties. It can be used as an antioxidant for high-temperature ceramics and refractory materials, and has an antioxidant protection effect on high-temperature ceramics and refractory materials under high-temperature use conditions. At present, the synthesis and preparation of Al4SiC4 materials are all one-dimensional grains. For example, Chinese patent CN202111464425.4 discloses an Al4SiC4-SiC composite refractory material for blast furnace body and its preparation method, using SiC as aggregate, adding metal Al powder, Si powder and C powder to prepare Al-Si-C-SiC green body, and synthesizing Al4SiC4 grains in situ in SiC matrix through chemical reaction between Al, Si and C at high temperature; Chinese patent CN115894037A discloses an Al4SiC4 combined with silicon carbide porous ceramic and its preparation method, using metal aluminum powder, elemental silicon powder, liquid phenolic resin and carbon black powder as raw materials for staged heat treatment to obtain Al4SiC4 grains combined with silicon carbide porous ceramics. However, the low specific surface area of ​​one-dimensional Al4SiC4 grains has limited improvement on the oxidation resistance of refractory materials, and the improvement on the mechanical properties of refractory materials is also insufficient. Therefore, there is an urgent need for a fire-free refractory material with higher oxidation resistance and mechanical properties. Summary of the Invention

[0004] The present invention aims to provide an aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers, as well as its preparation method and application. The aluminum carbon silicide in the refractory provided by the present invention has a two-dimensional whisker structure, resulting in the refractory material having improved oxidation resistance and mechanical properties.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides an aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers. The material comprises a matrix material and water. Calculated by mass percentage, the matrix material comprises: 4-10% large-particle brown corundum, 4-10% medium-particle brown corundum, 12-18% small-particle brown corundum, 29-35% fine-powder brown corundum, 14-20% silicon carbide, 1-5% high-alumina cement, 0.5-3% white corundum, 1-5% α-alumina, 2-8% aluminum powder, 0.6-1.4% silicon powder, 1-5% thermosetting phenolic resin, 1-7% graphite powder and 0.6-1.4% catalyst.

[0007] Preferably, the mass content of Al2O3 in the high alumina cement is ≥70%.

[0008] Preferably, the carbon content of the thermosetting phenolic resin is 40-50%.

[0009] Preferably, the catalyst comprises one or more of nickel nitrate, nickel oxide and nickel powder.

[0010] Preferably, the mass ratio of water to matrix material is (3-9):100.

[0011] The present invention provides a method for preparing the non-fired refractory material described in the above technical solution, comprising the following steps:

[0012] (1) mixing a base material and water to obtain a mixed material;

[0013] (2) The mixture obtained in step (1) is sequentially molded, vibrated, cured and dried to obtain a fire-free refractory material.

[0014] Preferably, the frequency of the molding and vibration in step (2) is 2700 to 2900 times / min, the amplitude of the molding and vibration is ±(0.4 to 0.6) mm, and the time of the molding and vibration is 10 to 30 minutes.

[0015] Preferably, the curing temperature in step (2) is 20-30° C., and the curing time is 24-48 hours.

[0016] Preferably, the drying temperature in step (2) is 100-120° C., and the drying time is 10-15 hours.

[0017] The present invention also provides the use of the unburned refractory material described in the above technical solution or the unburned refractory material prepared according to the preparation method described in the above technical solution in high-temperature industries.

[0018] The invention provides an aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers. The material comprises a matrix material and water. Calculated by mass percentage, the matrix material comprises: 4-10% large-particle brown corundum, 4-10% medium-particle brown corundum, 12-18% small-particle brown corundum, 29-35% fine-powder brown corundum, 14-20% silicon carbide, 1-5% high-alumina cement, 0.5-3% white corundum, 1-5% α-alumina, 2-8% aluminum powder, 0.6-1.4% silicon powder, 1-5% thermosetting phenolic resin, 1-7% graphite powder and 0.6-1.4% catalyst. During high-temperature use of the refractory material provided by the present invention, under the action of a catalyst, brown corundum, silicon carbide, high-alumina cement, white corundum and α-alumina form an alumina-silicon carbide matrix, and silicon powder, aluminum powder and graphite powder grow in situ to form Al4SiC4 whiskers; the Al4SiC4 material itself has an antioxidant effect. Compared with one-dimensional granular Al4SiC4, the Al4SiC4 whiskers have a two-dimensional linear structure and a larger surface area, and have better wrapping properties for matrix components inside the unfired refractory material. They are preferentially oxidized during oxidation, and have a better protection effect on other easily oxidized substances inside the unfired refractory material during the oxidation process. The Al4SiC4 whiskers also have the characteristics of the whiskers themselves, which can not only improve the oxidation resistance of the unfired refractory material, but also enhance the mechanical properties of the unfired refractory material; the thermosetting phenolic resin is used as a binder, has good high-temperature resistance, is carbonized during high-temperature use, and forms a carbon-containing refractory material with excellent thermal shock resistance and slag erosion resistance. The results of the examples show that the non-fired refractory material provided by the present invention has a compressive strength of more than 45 MPa, a flexural strength of more than 8 MPa, and an oxide layer thickness of less than 10 mm after high-temperature sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an SEM image of a sample of the unfired refractory material prepared in Example 1 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours;

[0020] Figure 2 This is an SEM image of a sample of the unfired refractory material prepared in Example 2 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours;

[0021] Figure 3 This is an SEM image of a sample of the unfired refractory material prepared in Example 3 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours;

[0022] Figure 4 This is an SEM image of a sample of the unfired refractory material prepared in Comparative Example 1 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours;

[0023] Figure 5SEM image of a sample of the unfired refractory material prepared in Example 1 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours, and an EDS image of Al4SiC4 whiskers in the sample;

[0024] Figure 6 This is the XRD pattern of a sample of the unfired refractory material prepared in Example 1 of the present invention after sintering at 1450° C. in a tube furnace with argon for 2.5 hours. DETAILED DESCRIPTION

[0025] The invention provides an aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers. The material comprises a matrix material and water. Calculated by mass percentage, the matrix material comprises: 4-10% large-particle brown corundum, 4-10% medium-particle brown corundum, 12-18% small-particle brown corundum, 29-35% fine-powder brown corundum, 14-20% silicon carbide, 1-5% high-alumina cement, 0.5-3% white corundum, 1-5% α-alumina, 2-8% aluminum powder, 0.6-1.4% silicon powder, 1-5% thermosetting phenolic resin, 1-7% graphite powder and 0.6-1.4% catalyst.

[0026] Unless otherwise specified, the present invention has no particular limitation on the sources of the components, and commercially available products known to those skilled in the art may be used.

[0027] The aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers provided by the present invention comprises a base material.

[0028] Calculated by mass percentage, the matrix material includes 4-10% of large-grained brown corundum, preferably 5-9%, more preferably 6-8%.

[0029] In the present invention, the particle size of the large-particle brown corundum is preferably 5 to 8 mm, more preferably 5.5 to 7.8 mm, and most preferably 5.5 to 7.5 mm.

[0030] Calculated by mass percentage, the matrix material includes 4-10% of medium-sized brown corundum, preferably 5-9%, and more preferably 6-8%.

[0031] In the present invention, the particle size of the medium-sized brown corundum is preferably 3 to 5 mm, more preferably 3.2 to 4.8 mm, and most preferably 3.5 to 4.5 mm.

[0032] Calculated by mass percentage, the matrix material includes 12-18% of small-grained brown corundum, preferably 13-17%, and more preferably 14-16%.

[0033] In the present invention, the particle size of the small-particle brown corundum is preferably 1 to 3 mm, more preferably 1.2 to 2.8 mm, and most preferably 1.5 to 2.5 mm.

[0034] Calculated by mass percentage, the matrix material includes 29-35% fine powdered brown corundum, preferably 30-34%, more preferably 31-33%.

[0035] In the present invention, the particle size of the fine powdered brown corundum is preferably ≤1 mm, more preferably 0.01 to 1 mm, and most preferably 0.09 to 1 mm.

[0036] In the present invention, the mass content of aluminum oxide in the large-grained brown corundum, medium-grained brown corundum, small-grained brown corundum and fine powdered brown corundum is preferably ≥90%, more preferably ≥92%, and most preferably ≥95%.

[0037] The present invention limits the particle size of brown corundum and the ratio of each particle size within the above range, and can achieve the most compact packing through the grading of different particle sizes. Large particles can resist high-temperature thermal shock, while small particles can fill gaps, making the refractory material present the densest state and improving the thermal shock resistance of the refractory material.

[0038] Calculated by mass percentage, the matrix material includes 14-20% silicon carbide, preferably 15-19%, more preferably 16-18%.

[0039] In the present invention, the silicon carbide particle size is preferably ≤1 mm, more preferably 0.01 to 1 mm, and most preferably 0.05 to 1 mm. The silicon carbide purity is preferably ≥98%, more preferably 98 to 99%, and most preferably 99%. In the present invention, the silicon carbide forms the refractory matrix, exhibiting excellent refractory properties. By limiting parameters such as the amount and particle size of silicon carbide within the aforementioned ranges, the present invention can ensure that the refractory contains an appropriate amount of silicon carbide, further improving the refractory's high-temperature resistance.

[0040] Calculated by mass percentage, the matrix material includes 1-5% high alumina cement, preferably 2-4%, more preferably 2.5-3.5%.

[0041] In the present invention, the Al2O3 mass content of the high-alumina cement is preferably ≥70%; the particle size of the high-alumina cement is preferably ≤50 nm, more preferably 10-50 nm, and most preferably 20-50 nm; and the purity of the high-alumina cement is preferably ≥98%, more preferably 98-99%, and most preferably 99%. In the present invention, the high-alumina cement is used to form an alumina-silicon carbide-carbon refractory matrix. By limiting the amount of high-alumina cement and other parameters within the aforementioned ranges, the present invention can further improve the high-temperature resistance of the refractory material.

[0042] Calculated by mass percentage, the matrix material includes 0.5-3% white corundum, preferably 1-2.5%, more preferably 1.5-2%.

[0043] In the present invention, the particle size of the white corundum is preferably ≤0.08 mm, more preferably 0.01 to 0.08 mm, and most preferably 0.02 to 0.08 mm. The purity of the white corundum is preferably ≥98%, more preferably 98 to 99%, and most preferably 99%. In the present invention, the white corundum itself has a high hardness and is added to the refractory material to improve the hardness and wear resistance of the refractory material. By limiting the amount of white corundum and other parameters within the above range, the hardness and wear resistance of the refractory material can be further improved.

[0044] Calculated by mass percentage, the matrix material includes 1-5% of α-alumina, preferably 2-4%, and more preferably 2.5-3.5%.

[0045] In the present invention, the particle size of the α-alumina is preferably ≤100 μm, more preferably 1 to 100 μm, and most preferably 50 to 100 μm. The purity of the α-alumina is preferably ≥98%, more preferably 98 to 99%, and most preferably 99%. In the present invention, the α-alumina can promote the densification of the refractory during high-temperature sintering, improving its high-temperature resistance. By limiting the amount of α-alumina and other parameters within the above ranges, the present invention can further improve the density of the refractory after sintering and enhance its high-temperature resistance.

[0046] Calculated by mass percentage, the matrix material includes 2-8% aluminum powder, more preferably 3-7%, and more preferably 4-6%.

[0047] In the present invention, the particle size of the aluminum powder is preferably ≤0.074mm, more preferably 0.01-0.074mm, and most preferably 0.02-0.074mm; the purity of the aluminum powder is preferably ≥98%, more preferably 98%-99%, and most preferably 99%. In the present invention, during the high-temperature use of the refractory material, the aluminum powder, silicon powder, and graphite powder are sintered under the action of a catalyst to generate Al4SiC4 whiskers in situ, thereby improving the oxidation resistance and mechanical properties of the refractory material. The present invention limits the parameters such as the amount of aluminum powder to the above range, so that the refractory material contains more Al4SiC4 whiskers, and the Al4SiC4 whiskers are uniform in thickness, further improving the performance of the refractory material.

[0048] Calculated by mass percentage, the matrix material includes 0.6-1.4% silicon powder, preferably 0.8-1.2%, and most preferably 0.9-1.1%.

[0049] In the present invention, the particle size of the silicon powder is preferably ≤0.074mm, more preferably 0.01-0.074mm, and most preferably 0.02-0.074mm; the purity of the silicon powder is preferably ≥2N, more preferably 2-3N. In the present invention, during the high-temperature use of the refractory material, the silicon powder, aluminum powder and graphite powder, under the action of a catalyst, are sintered to generate Al4SiC4 whiskers in situ, thereby improving the oxidation resistance and mechanical properties of the refractory material. The present invention limits the parameters such as the amount of silicon powder to the above range, so that the refractory material contains more Al4SiC4 whiskers, and the Al4SiC4 whiskers are uniform in thickness, further improving the performance of the refractory material.

[0050] Calculated by mass percentage, the matrix material includes 1-7% graphite powder, preferably 2-6%, more preferably 3-5%.

[0051] In the present invention, the particle size of the graphite powder is preferably ≤0.074mm, more preferably 0.01-0.074mm, and most preferably 0.02-0.074mm; the purity of the graphite powder is preferably ≥98%, more preferably 98%-99%, and most preferably 99%. In the present invention, during high-temperature use of the refractory material, the graphite powder, aluminum powder, and silicon powder, under the action of a catalyst, are sintered to generate Al4SiC4 whiskers in situ, thereby improving the oxidation resistance and mechanical properties of the refractory material. The present invention limits the amount of graphite powder and other parameters within the above range, which can ensure that the refractory material contains a large amount of Al4SiC4 whiskers, and the Al4SiC4 whiskers are uniform in thickness, further improving the performance of the refractory material.

[0052] Calculated by mass percentage, the matrix material includes 0.6-1.4% of the catalyst, preferably 0.8-1.2%, more preferably 0.9-1.1%.

[0053] In the present invention, the catalyst preferably comprises one or more of nickel nitrate, nickel oxide, and nickel powder. In the present invention, the catalyst particle size is preferably ≥200 nm, more preferably 200 nm to 2 μm, and most preferably 300 nm to 1 μm; the catalyst purity is preferably ≥98%, more preferably 98% to 99%, and most preferably 99%. In the present invention, the catalyst is used to catalyze the in-situ formation of Al4SiC4 whiskers during the high-temperature sintering process of graphite powder, aluminum powder, and silicon powder, thereby improving the oxidation resistance and mechanical properties of the refractory material. By limiting the catalyst dosage to the aforementioned range, the present invention enables the graphite powder to fully react with the aluminum powder and silicon powder, further improving the performance of the refractory material.

[0054] In terms of mass percentage, the matrix material comprises 1-5%, preferably 2-4%, and more preferably 2.5-3.5% of a thermosetting phenolic resin. In the present invention, the thermosetting phenolic resin is preferably thermosetting phenolic resin 2130. In the present invention, the thermosetting phenolic resin is used as a binder to shape the refractory material. The use of the thermosetting phenolic resin as a binder in the present invention is not only conducive to the shaping of the refractory material, but also has excellent high temperature resistance, can maintain the integrity of the refractory material structure under high temperature conditions, and the carbon formed after carbonization can further improve the performance of the refractory material.

[0055] In the present invention, the carbon content of the thermosetting phenolic resin is preferably 40-50%. The present invention limits the carbon content of the thermosetting phenolic resin to the above range. Thermosetting phenolic resin will carbonize and form voids under high temperature conditions. Too low a carbon content will result in larger voids, which is not conducive to the density of the material, while too high a carbon content will result in poor bonding effect.

[0056] The aluminum oxide-silicon carbide-carbon unfired refractory material reinforced with aluminum carbon silicide whiskers provided by the present invention also includes water.

[0057] In the present invention, the water preferably includes purified water, ultrapure water or tap water.

[0058] In the present invention, the mass ratio of water to matrix material is preferably (3-9):100, more preferably (4-8):100, and most preferably (5-7):100. By limiting the mass ratio of water to matrix material to the above range, the present invention can ensure that the two have suitable fluidity after mixing, which is beneficial for subsequent molding.

[0059] During high-temperature use of the refractory material provided by the present invention, silicon powder, aluminum powder and graphite powder grow in situ under the action of a catalyst to form Al4SiC4 whiskers. Compared with one-dimensional granular Al4SiC4, the Al4SiC4 whiskers have a two-dimensional linear structure and a larger surface area, and can better wrap the matrix components inside the unfired refractory material. By controlling the composition and dosage of each component and cooperating with each component, not only can the oxidation resistance of the unfired refractory material be improved, but also the mechanical properties of the unfired refractory material can be enhanced.

[0060] The present invention provides a method for preparing the non-fired refractory material described in the above technical solution, comprising the following steps:

[0061] (1) mixing a base material and water to obtain a mixed material;

[0062] (2) The mixture obtained in step (1) is sequentially molded, vibrated, cured and dried to obtain a fire-free refractory material.

[0063] The present invention mixes the base material and water to obtain a mixed material.

[0064] In the present invention, the base material and water are preferably mixed by: dissolving the thermosetting phenolic resin in water to obtain a mixture A; dry-mixing the remaining other components in the base material to obtain a mixture B; and then adding the mixture A to the mixture B and stirring.

[0065] In the present invention, the dry mixing time is preferably 30 to 60 minutes, preferably 40 to 60 minutes, and most preferably 50 to 60 minutes; the stirring time is preferably 5 to 10 minutes, more preferably 6 to 9 minutes, and most preferably 7 to 8 minutes. The mixing method and mixing time of the present invention can make the components mix more evenly.

[0066] After obtaining the mixture material, the present invention sequentially performs molding, vibration, curing and drying on the mixture material to obtain the unfired refractory material.

[0067] In the present invention, the frequency of the molding and compaction is preferably 2700 to 2900 times / min, more preferably 2700 to 2800 times / min; the amplitude of the molding and compaction is preferably ±(0.4 to 0.6) mm, more preferably ±(0.4 to 0.5) mm; and the time of the molding and compaction is preferably 10 to 30 minutes, more preferably 20 to 30 minutes. The present invention limits the molding and compaction parameters to the above ranges, which can ensure that the mixed material is fully compacted.

[0068] In the present invention, the molding and compaction is preferably carried out in a mold. The present invention has no special limitation on the structure and size of the mold, which can be selected according to actual needs.

[0069] In the present invention, the curing temperature is preferably 20-30°C, more preferably 25-30°C; the curing time is preferably 24-48 hours, more preferably 30-45 hours, and most preferably 35-40 hours. In the present invention, oxidation is used to accelerate material hardening, slow water loss, prevent cracking, and increase material hardness. By limiting the curing parameters to the above ranges, the present invention can further improve the hardness of the refractory material.

[0070] In the present invention, the drying temperature is preferably 100-120° C., more preferably 105-115° C., and most preferably 110° C.; the drying time is preferably 10-15 h, more preferably 12-14 h, and most preferably 13 h.

[0071] The present invention controls parameters such as the temperature and time of molding, curing and drying, thereby improving the density and hardness of the refractory material and further improving its high-temperature resistance during high-temperature use.

[0072] The present invention also provides the use of the unburned refractory material described in the above technical solution or the unburned refractory material prepared according to the preparation method described in the above technical solution in high-temperature industries.

[0073] In the present invention, the temperature of the unfired refractory material when used in high-temperature industries is preferably ≤1600°C.

[0074] The present invention has no special limitation on the operation of using the unburned refractory material or the unburned refractory material prepared according to the preparation method described in the above technical solution in high temperature industries. The technical solution for the application of unburned refractory materials in high temperature industries that is familiar to those skilled in the art can be adopted.

[0075] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0076] In each embodiment: the particle size of large-particle brown corundum is 5-8 mm, the particle size of medium-particle brown corundum is 3-5 mm, the particle size of small-particle brown corundum is 1-3 mm, the particle size of fine powder brown corundum is 0.09-1 mm, and the mass content of aluminum oxide in the brown corundum is 95%; the particle size of silicon carbide fine powder is 0.074 mm, the purity is 99%, the particle size of high alumina cement is 30 nm, the purity is 99%, and the mass content of aluminum oxide in the high alumina cement is 75%; white The particle size of corundum is 0.08mm and the purity is 99%; the particle size of α-alumina is 0.074mm and the purity is 99%; the particle size of aluminum powder is 0.074mm and the purity is 99%; the particle size of silicon powder is 0.074mm and the purity is 2N; the thermosetting phenolic resin is 2130 type, with a purity of 70% and a carbon content of 45%; the particle size of graphite powder is 0.074mm and the purity is 99%; the particle size of catalyst is 200nm and the purity is 99%.

[0077] Example 1

[0078] In this embodiment, the Al4SiC4 whisker reinforced Al2O3-SiC-C unfired refractory material is composed of a matrix material and water. In terms of mass percentage, the matrix material is composed of 7% large-particle brown corundum, 7% medium-particle brown corundum, 15% small-particle brown corundum, 32% fine brown corundum, 17% fine silicon carbide powder, 3% high-alumina cement, 2% white corundum, 3% α-alumina, 5% aluminum powder, 1% silicon powder, 3% thermosetting phenolic resin, 4% graphite powder and 1% nickel nitrate catalyst; the mass ratio of water to matrix material is 6:100;

[0079] The preparation method of the non-burning refractory material is as follows:

[0080] Thermosetting phenolic resin was dissolved in water to obtain mixture A. The remaining components in the matrix material were dry-mixed in a mixer according to the proportion for 55 minutes, and then mixture A was added and stirred for 8 minutes. After uniform mixing, the mixture was poured into a 40mm×40mm×160mm mold. The filled mold was placed on a vibration table and vibrated at a frequency of 2700 times / min and an amplitude of 0.4mm for 30 minutes to form the mold. The vibrated sample was placed in the mold and cured at 30°C for 40 hours, and then dried in an oven at 110°C for 13 hours.

[0081] Example 2

[0082] The catalyst in Example 1 was replaced with nickel oxide, and other parameters were the same as those in Example 1.

[0083] Example 3

[0084] The catalyst in Example 1 was replaced with nickel powder, and other parameters were the same as those in Example 1.

[0085] Comparative Example 1

[0086] The catalyst in Example 1 was omitted, and other parameters were the same as those in Example 1.

[0087] Application Examples

[0088] The unfired refractory materials prepared in Examples 1 to 3 and Comparative Example 1 were sintered in a tubular furnace at 1450° C. for 2.5 hours while introducing argon gas.

[0089] The samples of the unfired refractory materials prepared in Examples 1 to 3 and Comparative Example 1 were observed by scanning electron microscopy after sintering at 1450°C in a tube furnace with argon for 2.5 hours. The SEM images obtained are as follows: Figures 1 to 4 As shown. Figure 1 It can be seen that when nickel nitrate is used as a catalyst, Al4SiC4 whiskers grow in large quantities in the weak parts of the matrix and pores, with the largest whisker diameter and surface area. It can be observed that there are obvious catalyst alloy balls on the top of the catalytically grown Al4SiC4 whiskers, which proves that the Al4SiC4 whiskers grow by a gas-liquid-solid catalytic mechanism. The large aspect ratio and specific surface area of ​​Al4SiC4 whiskers make the Al2O3-SiC-C unfired refractory material have excellent mechanical properties and high-temperature oxidation resistance. Figure 2 It can be seen from the graph that when nickel oxide is used as the catalyst, the aspect ratio of the Al4SiC4 whiskers is smaller than that of Example 1. Figure 3 It can be seen that when nickel powder is used as catalyst, the aspect ratio of Al4SiC4 whiskers is the smallest. Figure 4 It can be seen that when the raw material does not contain a catalyst, no Al4SiC4 whiskers are generated.

[0090] By comparing the SEM results of Examples 1 to 3 and Comparative Example 1, it can be seen that by changing the type of catalyst, the diameters of the Al4SiC4 whiskers grown inside the Al2O3-SiC-C unfired refractory material are also different. Due to the high-temperature decomposition of the nickel nitrate catalyst, the local oxygen partial pressure inside the refractory material increases. According to the gas-liquid-solid whisker growth mechanism, the increase in gaseous silicon monoxide and carbon monoxide prolongs the growth time of the Al4SiC4 whiskers. Therefore, the Al4SiC4 whisker diameter and specific surface area prepared with the nickel nitrate catalyst are the largest, and Al4SiC4 cannot grow into whiskers without a catalyst.

[0091] The SEM image of the sample of the fire-free refractory material prepared in Example 1 after sintering at 1450℃ in a tube furnace with argon for 2.5h and the EDS image of the Al4SiC4 whiskers in the sample are as follows: Figure 5 As shown. Figure 5 It can be seen that the whiskers are composed of four elements: Al, Si, C and Ni.

[0092] The XRD pattern of the sample of the fire-free refractory material prepared in Example 1 after sintering at 1450°C in a tube furnace with argon for 2.5 hours is as follows: Figure 6 As shown. Figure 6 The XRD test results prove that Al4SiC4 whiskers were synthesized. Since the brown corundum raw material contains alumina and a small amount of impurity silica, there are also characteristic peaks of alumina and silica in the XRD. However, due to the small amount of catalyst added, no characteristic peaks of the catalyst were found.

[0093] The Al4SiC4 whisker reinforced Al2O3-SiC-C unfired refractory materials prepared in Examples 1 to 3 and Comparative Example 1 were tested for room temperature compressive strength, room temperature flexural strength and oxidation resistance. The room temperature compressive strength test of the refractory materials was carried out in accordance with the standard test method of GB / T 5072-2008, and the room temperature flexural strength test of the refractory materials was carried out in accordance with the standard test method of GB / T 3001-2007. The above two tests were carried out on a YAW300D compression and flexural integrated machine. The high-temperature oxidation resistance of the samples was tested in an open tube furnace at a temperature of 1500°C, a heating rate of 5°C / min, and a test time of 2 hours. The test results are shown in Table 1.

[0094] Table 1 Room temperature compressive strength, room temperature flexural strength and high temperature oxidation resistance of Al4SiC4 whisker reinforced Al2O3-SiC-C unfired refractory materials prepared in Examples 1 to 3 and Comparative Example 1

[0095] sample Compressive strength at room temperature Flexural strength at room temperature Oxide layer thickness Example 1 <![CDATA[55.31 MPa ]]> <![CDATA[13.52 MPa ]]> 4.8mm Example 2 <![CDATA[48.95 MPa ]]> <![CDATA[10.84 MPa ]]> 7.4mm Example 3 <![CDATA[45.32 MPa ]]> <![CDATA[8.93 MPa ]]> 9.5mm Comparative Example 1 <![CDATA[34.21 MPa ]]> <![CDATA[6.21 MPa ]]> 22.9mm

[0096] By comparing the performance test results of Examples 1 to 3 and Comparative Example 1 in Table 1, it can be seen that the Al4SiC4 whisker reinforced Al2O3-SiC-C unfired refractory material prepared by the present invention has excellent mechanical properties and oxidation resistance, while after omitting the catalyst, the mechanical properties and oxidation resistance of the obtained Al2O3-SiC-C unfired refractory material are significantly reduced.

[0097] In summary, the aluminum carbide in the refractory material provided by the present invention has a two-dimensional whisker structure, and the refractory material has better oxidation resistance and mechanical properties.

[0098] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A carbon silicide aluminum whisker reinforced alumina-silicon carbide-carbon unfired refractory material, composed of a matrix material and water; the matrix material comprises, by mass percentage, 4-10% large-particle brown corundum, 4-10% medium-particle brown corundum, 12-18% small-particle brown corundum, 29-35% fine-powder brown corundum, 14-20% silicon carbide, 1-5% high-alumina cement, 0.5-3% white corundum, 1-5% α-alumina, 2-8% aluminum powder, 0.6-1.4% silicon powder, 1-5% thermosetting phenolic resin, and graphite powder. 1-7% of aluminum and 0.6-1.4% of a catalyst; the catalyst comprises one or more of nickel nitrate, nickel oxide and nickel powder; the particle size of the large-particle brown corundum is 5-8 mm, the particle size of the medium-particle brown corundum is 3-5 mm, the particle size of the small-particle brown corundum is 1-3 mm, the particle size of the fine powder brown corundum is 0.09-1 mm, the particle size of the silicon carbide is 0.05-1 mm, the particle size of the white corundum is 0.02-0.08 mm, and the particle size of the α-alumina is 50-100 μm; The method for preparing the unburned refractory material comprises the following steps: (1) mixing a base material and water to obtain a mixture; the mixing of the base material and water comprises: dissolving a thermosetting phenolic resin in water to obtain a mixture A; dry-mixing the remaining other components in the base material to obtain a mixture B; and then adding the mixture A to the mixture B and stirring; (2) The mixture obtained in step (1) is sequentially molded, vibrated, cured and dried to obtain a fire-free refractory material.

2. The fire-free refractory material according to claim 1, characterized in that: The mass content of Al2O3 in the high alumina cement is ≥70%.

3. The fire-free refractory material according to claim 1, characterized in that: The carbon content of the thermosetting phenolic resin is 40-50%.

4. The fire-free refractory material according to claim 1, characterized in that: The mass ratio of the water to the matrix material is (3-9):

100.

5. The method for preparing the unburned refractory material according to any one of claims 1 to 4, comprising the following steps: (1) mixing a base material and water to obtain a mixture; the mixing of the base material and water comprises: dissolving a thermosetting phenolic resin in water to obtain a mixture A; dry-mixing the remaining other components in the base material to obtain a mixture B; and then adding the mixture A to the mixture B and stirring; (2) The mixture obtained in step (1) is sequentially molded, vibrated, cured and dried to obtain a fire-free refractory material.

6. The preparation method according to claim 5, characterized in that The frequency of the molding and vibration in the step (2) is 2700 to 2900 times / min, the amplitude of the molding and vibration is ±(0.4 to 0.6) mm, and the time of the molding and vibration is 10 to 30 minutes.

7. The preparation method according to claim 5, characterized in that The curing temperature in step (2) is 20-30° C., and the curing time is 24-48 hours.

8. The preparation method according to claim 5, characterized in that The drying temperature in step (2) is 100-120° C., and the drying time is 10-15 hours.

9. Use of the unburned refractory material according to any one of claims 1 to 4 or the unburned refractory material prepared according to the preparation method according to any one of claims 5 to 8 in high-temperature industries.

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