High-purity high-strength corundum brick and preparation method thereof

Abstract

The invention discloses a high-purity and high-strength corundum brick and a preparation method thereof, and the high-purity and high-strength corundum brick is characterized by comprising the following components in percentage by weight: 10-30% of a high-strength corundum brick body, 10-30% of a high-strength corundum brick body and 10-30 The high-temperature-resistant ceramic glaze is prepared from, by weight, 30%-50% of white corundum with the particle size being 1-2 mm, 10%-30% of white corundum with the particle size being 0-1 mm, 20%-40% of white corundum with the particle size being 180 meshes, 1%-10% of alpha-Al2O3, 1%-5% of Guangxi white mud, 1%-5% of aluminum dihydrogen phosphate dry powder, 1%-5% of petalite and 1%-5% of pseudo-boehmite. According to the invention, petalite and pseudo-boehmite are adopted as a composite mineralizer, so that the firing temperature of the high-purity and high-strength corundum brick can be reduced from 1700 DEG C to 1450 DEG C, fuel can be saved by 30-40%, the corundum brick is more energy-saving and environment-friendly, and the cost can be reduced by 10-20%.

Description

Technical Field

[0001] The present invention relates to the technical field of refractory material processing, in particular to a high-purity and high-strength corundum brick and a preparation method thereof. Background Art

[0002] In order to improve the performance of fused white corundum, appropriately extend the crystal development time of white corundum after smelting, and allow the corundum grains to have more sufficient growth time, it is necessary to pour the smelted white corundum solution into a corundum ladle for slow cooling. At the same time, in order to prevent the corundum ladle lining material from introducing impurities to contaminate the white corundum solution, the corundum ladle lining material needs to be able to withstand the high temperature impact of 2000℃ and not precipitate other substances into the white corundum solution to contaminate the white corundum solution. Therefore, the development of a corundum ladle lining material that meets the above requirements is an urgent need in the white corundum smelting industry. Hydrogen, as the lightest and most active element known, will undergo a substitution reaction with oxides such as silicon dioxide and magnesium oxide, continuously taking away oxygen atoms from silicon dioxide and magnesium oxide. Among the currently known refractory materials, high-purity corundum products have the strongest resistance to hydrogen. Therefore, the development of a high-purity and more economical corundum product is of great significance to promoting the development of the hydrogen-containing thermal equipment industry.

[0003] The main problem in preparing high-purity and high-strength corundum bricks at present is that the sintering temperature is high and needs to be above 1700℃ for full sintering, the sintering cost is high, the requirements for the kiln used for sintering are high, and the construction cost is high. Summary of the Invention

[0004] The present invention aims to provide a high-purity, high-strength corundum brick and its preparation method. By adding a mineralizer, the firing temperature of the corundum brick can be reduced from the current 1700°C to below 1500°C, thereby saving energy and improving its economic efficiency. The high-purity, high-strength corundum brick should have better high-temperature performance, longevity, cost-effectiveness, and improved resistance to hydrogen corrosion.

[0005] The object of the present invention is achieved like this: A high-purity and high-strength corundum brick, characterized in that it comprises the following components, calculated by weight percentage, 30-50% of white corundum with a particle size of 1-2 mm, 10-30% of white corundum with a particle size of 0-1 mm, 20-40% of white corundum with a particle size of 180 mesh, 1-10% of α-Al2O3, 1-5% of Guangxi white mud, 1-5% of aluminum dihydrogen phosphate dry powder, 1-5% of petalite, and 1-5% of pseudo-boehmite.

[0006] The particle size of the α-Al2O3 is ≤50 μm.

[0007] The particle size of the Guangxi white mud is ≤180 meshes.

[0008] The particle size of the aluminum dihydrogen phosphate dry powder is ≤200 mesh.

[0009] The particle size of the eucryptite is ≤325 mesh, and the particle size of the pseudoboehmite is ≤325 mesh.

[0010] A preparation method of high-purity high-strength corundum brick comprises the following steps: S1, α-Al2O3, Guangxi white mud, aluminum dihydrogen phosphate dry powder, pseudoboehmite and eucryptite are premixed to obtain a premix; S2, the premix obtained in S1 is added into tap water and put into a ball mill for grinding to obtain a ground material; S3, the ground material obtained in S2 is put into a double-wheel wet mill and mixed with white corundum with a particle size of 1-2 mm, white corundum with a particle size of 0-1 mm and white corundum with a particle size of 180 mesh for 6-10 minutes to obtain a wet milled material; S4, the wet milled material obtained in S3 is put into an air compressor grinding tool for pressing to obtain a pressed piece; S5, the pressed piece is fired to obtain a high-purity high-strength corundum brick.

[0011] In S2, the weight of the tap water is 6% of the premix, and the grinding time is 6-7 hours.

[0012] The beneficial effects of the present application are: 1. The eucryptite and pseudoboehmite are used as composite mineralizers in the present application, so that the firing temperature of the high-purity high-strength corundum brick can be reduced from 1700℃ to 1450℃, which can save fuel by 30-40%, is more energy-saving and environmentally friendly, and can reduce the cost by 10-20%, which has significant economic benefits. Pseudoboehmite is a key material for preparing high-efficiency catalyst carriers due to its high specific surface area and controllable pore structure, and as a precursor of alumina ceramic, low-temperature calcination (500-800℃) can generate high-purity α-Al2O3, and eucryptite as a strong cosolvent can form a liquid phase with pseudoboehmite powder at about 1300℃, which can wrap corundum particles to form a network structure, thereby achieving the purpose of reducing the sintering temperature. The simultaneous addition of both has the best effect on reducing the sintering temperature and improving the sintering efficiency, the addition of eucryptite only has a secondary effect, and the addition of pseudoboehmite only has a very limited effect, thereby reducing the sintering temperature and accelerating the sintering rate.

[0013] 2. Due to the liquid phase filling into the gaps of corundum particles during firing, a network structure is formed, which greatly improves the structural strength of the high-purity high-strength corundum brick, and the cold compressive strength can reach more than 180Mpa, which has a longer service life and better effect.

[0014] 3. Due to the high mineralization efficiency of the composite mineralizer, the content of other components introduced is greatly reduced, the Al2O3 content of the high-purity high-strength corundum brick is improved, and the actual measurement of the newly developed high-purity high-strength corundum brick shows that the Al2O3 content can reach 99.3%. The improvement of the Al2O3 content improves the resistance of the high-purity high-strength corundum brick to hydrogen element corrosion. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the examples.

[0016] A method for preparing high-purity and high-strength corundum bricks comprises the following steps: S1. Premixing α-Al2O3, Guangxi white mud, aluminum dihydrogen phosphate dry powder, pseudo-boehmite and petalite to obtain a premix.

[0017] S2. The premix obtained in S1 was added with tap water and ground in a ball mill to obtain a grind; the weight of the tap water was 6% of the premix, and the grinding time was 6 h.

[0018] S3. The ground material obtained in S2 is placed in a double-wheel wet mill and mixed with white corundum with a particle size of 1-2 mm, white corundum with a particle size of 0-1 mm, and white corundum with a particle size of 180 mesh for 6 to 10 minutes to obtain a wet-milled material.

[0019] S4. Put the wet milled material obtained in S3 into an air compressor mold for compaction to obtain a compacted part.

[0020] S5. Firing the pressed part to obtain high-purity and high-strength corundum bricks. The firing temperature and time are shown in Table 2.

[0021] The ingredients of Example 1 to Example 5 are shown in Table 1 Result analysis: From the experimental data analysis of Example 1, Example 2, Example 3, Example 4 and Example 5, it can be seen that: By comparing Example 1 and Example 2, except that Example 2 lacks the composite mineralizer (petalite and pseudo-boehmite), the rest use the same ratio, adopt the same production and firing process, and the test results show that Example 1 is significantly better than Example 2, indicating that the composite mineralizer has a significant improvement effect on the sintering and performance of high-purity and high-strength corundum bricks.

[0022] From the comparison between Example 2 and Example 5, it can be seen that in order to achieve sintering without adding a composite mineralizer, the sintering temperature needs to reach at least 1700°C. The porosity, pressure resistance, flexural strength and load softening temperature of Example 2 all indicate that it has not been fully sintered, which can also be found from the cross-section of the product after sintering.

[0023] From the comparison between Example 1 and Example 5, it can be seen that the addition of the composite mineralizer can not only reduce the sintering temperature from 1700°C to 1450°C, but the network structure formed at high temperature also makes the porosity, pressure resistance and flexural strength of the high-purity and high-strength corundum bricks of Example 1 significantly better than those of Example 5.

[0024] From the comparison of Example 1, Example 2, Example 3 and Example 4, it can be seen that Example 3, in which petalite is added alone, can achieve a certain effect of lowering the sintering temperature, but the effect is limited. Under the same firing conditions as Example 1, the performance of the fired product is significantly inferior to that of Example 1, but compared with Example 2 in which no mineralizer is added, the performance of the fired product is better than that of Example 2, indicating that the addition of petalite alone can achieve a mineralization effect, but the effect is not good enough. From the comparison of Example 4 in which pseudo-boehmite is added alone and Example 2 without adding a mineralizer, there is no obvious effect.

[0025] In summary, from the comparison between Example 1 in which a composite mineralizer of petalite and pseudo-boehmite is added and other examples, it can be seen that pseudo-boehmite is a key material for preparing a high-efficiency catalyst carrier due to its high specific surface area and controllable pore structure. As a precursor of alumina ceramics, low-temperature calcination (500-800°C) can generate high-purity α-Al2O3, while petalite, as a strong co-solvent, can form a liquid phase with pseudo-boehmite powder at around 1300°C, wrapping the corundum particles to form a network structure, thereby achieving the purpose of lowering the sintering temperature. The simultaneous addition of both has the best effect on lowering the sintering temperature and improving the sintering efficiency. The effect of adding only petalite is second only to that of adding only pseudo-boehmite, and the effect of adding only pseudo-boehmite is very limited.

Claims

1. A high-purity and high-strength corundum brick, characterized in that: The invention comprises the following components by weight percentage: 30-50% of white corundum with a particle size of 1-2 mm, 10-30% of white corundum with a particle size of 0-1 mm, 20-40% of white corundum with a particle size of 180 mesh, 1-10% of α-Al2O3, 1-5% of Guangxi white mud, 1-5% of dry aluminum dihydrogen phosphate powder, 1-5% of petalite and 1-5% of pseudo-boehmite.

2. The high-purity and high-strength corundum brick according to claim 1, characterized in that: The particle size of the α-Al2O3 is ≤50 μm.

3. The high-purity and high-strength corundum brick according to claim 1, characterized in that: The particle size of the Guangxi white mud is ≤180 meshes.

4. The high-purity and high-strength corundum brick according to claim 1, characterized in that: The particle size of the aluminum dihydrogen phosphate dry powder is ≤200 mesh.

5. The high-purity and high-strength corundum brick according to claim 1, characterized in that: The particle size of the petalite is ≤325 mesh, and the particle size of the pseudo-boehmite is ≤325 mesh.

6. A method for preparing high-purity and high-strength corundum bricks, characterized in that: The following steps are involved: S1. Premixing α-Al2O3, Guangxi white mud, aluminum dihydrogen phosphate dry powder, pseudo-boehmite and petalite to obtain a premix; S2, adding tap water to the premix obtained in S1 and grinding it in a ball mill to obtain a grind; S3, the grinding material obtained in S2 is placed in a double-wheel wet mill and mixed with white corundum with a particle size of 1-2 mm, white corundum with a particle size of 0-1 mm, and white corundum with a particle size of 180 mesh for 6 to 10 minutes to obtain a wet grinding material; S4, placing the wet-milled material obtained in S3 into an air compressor mold for compaction to obtain a compacted part; S5. sinter the pressed parts to obtain high-purity and high-strength corundum bricks.

7. The method for preparing high-purity and high-strength corundum bricks according to claim 6, characterized in that: In S2, the weight of tap water is 6% of the premix, and the grinding time is 6-7 hours.

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