Multi-composite-phase corundum mullite brick and preparation method thereof

Abstract

The invention relates to a multi-composite-phase corundum mullite brick, and relates to the technical field of refractory materials. The multi-composite-phase corundum mullite brick is prepared by firing tabular corundum, white corundum, andalusite, chrome green, electric smelting chromic oxide sand, zirconite powder and calcined alumina powder. According to the multi-composite-phase corundum-mullite brick disclosed by the invention, the multi-phase composite corundum-mullite brick prepared from corundum, mullite, aluminum-chromium eutectic melt, zirconium oxide and the like is formed through conversion and solid melting at high temperature according to the raw material components and content design, and the multi-composite-phase corundum-mullite brick has excellent erosion resistance and thermal shock resistance and has excellent use performance. The invention also relates to a preparation method of the multi-composite-phase corundum mullite brick.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically relating to a multi-phase corundum-mullite brick. In particular, this invention relates to a refractory material that can be used in key components such as kiln linings, kiln furniture, and insulation layers in high-temperature industries such as metallurgy and building materials, and improves their service life. Background Technology

[0002] Mullite (3Al2O3·2SiO2) is a high-quality refractory material with low thermal expansion, high melting point, high creep resistance, good high-temperature mechanical stability, and corrosion resistance, but it is difficult to completely densify. Corundum, on the other hand, is a second-phase material that can significantly improve the mechanical properties and density of mullite ceramic materials. Combining corundum with mullite ceramic materials allows for the control of glass phase formation. Corundum-mullite materials are multiphase materials composed of corundum and mullite phases, combining the excellent properties of both. Due to their good high-temperature mechanical properties and thermal shock resistance, they are widely used in key components such as kiln linings, kiln furniture, and insulation layers in high-temperature industries such as metallurgy and building materials.

[0003] Chinese invention patent CN112573932B discloses a homogeneous resintered electrofused zircon-mullite brick, in which the aggregate and matrix are both zircon-mullite mineral phases. The raw materials include 35-50% electrofused zircon-mullite with a particle size of 1mm < ≤ 3mm, 20-30% electrofused zircon-mullite with a particle size of 0.1mm ≤ ≤ 1mm, 0-35% electrofused zircon-mullite with a particle size ≤ 0.045mm, 0-20% electrofused white corundum with a particle size ≤ 0.045mm, 0-10% 65 zircon powder with a particle size ≤ 0.045mm, and 0-5% Suzhou clay with a particle size ≤ 0.045mm. The slurry is shaped into green bodies, then dried and fired to obtain homogeneous resintered electrofused zircon-mullite bricks. The drying temperature is 80-120℃ for 24-48 hours; the firing temperature is 1500-1600℃ for 6-12 hours. The homogeneous resintered electrofused zircon-mullite bricks have good resistance to steam erosion in glass kilns and thermal shock.

[0004] Chinese invention patent CN103496992B discloses a chromium-zirconium mullite refractory brick, which uses fused or sintered mullite as aggregate and zircon powder, corundum powder, and chromium oxide green as the matrix. The weight ratio of the refractory material raw materials is 65% mullite, 10% corundum powder, 15% zircon powder, and 10% chromium oxide green, with approximately 3% pulp as a binder. After thorough mixing, the mixture is allowed to stand for 8 hours, or directly formed using a press. After drying, the brick is fired at approximately 1650℃ for 4 hours. The sintered chromium-zirconium mullite refractory products are mainly used in glass kilns and steel and chemical kilns, exhibiting good thermal shock resistance, high-temperature crack resistance, and strong high-temperature slag resistance.

[0005] However, in modern manufacturing processes, due to harsh operating environments, existing composite phase corundum-mullite bricks face severe challenges. For example, in melting furnaces where temperatures fluctuate significantly, existing chromium-zirconium composite phase corundum-mullite refractory materials struggle to achieve stable and excellent thermal shock resistance while maintaining good erosion resistance. Summary of the Invention

[0006] In order to obtain a combination of excellent erosion resistance and thermal shock resistance, the present invention aims to provide a multi-composite phase corundum mullite brick and its preparation method.

[0007] The present invention discloses a multi-phase corundum-mullite brick, which is prepared by adding a binder to the following components and firing at a high temperature of 1500-1600℃, wherein:

[0008] Plate-shaped corundum particles with a diameter of 5-3 mm, 5-10%;

[0009] Particles with a diameter of 3–1 mm, 10–25%;

[0010] White corundum particles with a diameter of 3-1 mm, 5-15%;

[0011] Particles with a diameter of 1–0.1 mm, 10–20%;

[0012] Fine powder with a particle size of less than 74μm, 10-15%;

[0013] andalusite particles with a diameter of 1–0.1 mm, accounting for 5–15%;

[0014] Fine powder with a particle size of less than 74μm, 3-15%;

[0015] Chromium green fine powder with a particle size of less than 30 μm, 3-5%;

[0016] Electrofused chromium oxide particles with a diameter of 1–0.1 mm, 0–10%;

[0017] Zircon powder with a particle size of less than 15μm, 5-20%;

[0018] 1-10% of fine powder of calcined alumina with a particle size of less than 15μm;

[0019] The sum of the weight percentages of the above components is 100%.

[0020] The composite addition of tabular corundum and white corundum is 50-75%, andalusite is 10-25%, chrome green is 3-5%, fused chromium oxide sand is 0-10%, zircon is 5-20%, and calcined alumina powder is 1-10%, and the sum of the weight percentages of the above components is 100%.

[0021] The composite addition of tabular corundum and white corundum is 60-75%, andalusite is 10-20%, chrome green is 3-5%, fused chromium oxide sand is 0-10%, zircon is 5-15%, and calcined alumina powder is 1-5%, and the sum of the weight percentages of the above components is 100%.

[0022] Specifically, when the amount of chrome green added is less than 5%, the fused chromium oxide is not added; when the amount of chrome green added is 5%, the amount of fused chromium oxide added is 0-10%.

[0023] The tabular corundum contains >99% Al2O3 and has a bulk density ≥3.5 g / cm³. 3 White fused alumina has an Al2O3 content >99% and a bulk density ≥3.5 g / cm³. 3 The calcined alumina powder has an Al2O3 content of ≥99%.

[0024] The andalusite contains ≥57% Al2O3 and ≤1.0% Fe2O3.

[0025] The zircon contains ZrO2+HfO2≥65%, SiO2≥32%, and Fe2O3 content≤0.5%.

[0026] The Cr2O3 content in the fused chromium oxide is ≥99%, and the Cr2O3 content in the chromium green is ≥99%.

[0027] This invention also relates to a method for preparing the above-mentioned multi-phase corundum-mullite bricks, comprising the following steps:

[0028] a. Weigh each raw material according to the component ratio of the above claims, place the fine powder of each raw material in a premixer for premixing for a time of not less than 30 minutes, and obtain premixed powder;

[0029] b. Place the granules of each raw material in a mixer and mix them, then add a binder and mix, then add the premixed powder from step a and mix to obtain a mixture.

[0030] c. Add the mixture obtained in step b into the assembled mold and press it to form a brick blank;

[0031] d. After drying, the formed brick blanks are fired at a high temperature of 1500-1600℃ and held for 8-12 hours to obtain the multi-composite phase corundum mullite bricks.

[0032] The binder is aluminum dihydrogen phosphate, and the amount added is 3-5% of the total weight of the above raw materials.

[0033] Compared with the prior art, the multi-composite phase corundum mullite brick and its preparation method of the present invention have the following beneficial effects:

[0034] The multi-phase corundum-mullite brick of this invention uses tabular corundum, white corundum, andalusite, chromium oxide, desilicationized zirconium, and other main raw materials. It employs phosphate bonding and is formed at high temperatures through conversion and solidification into a multi-phase composite of corundum, mullite, aluminum-chromium eutectic, and zirconium oxide. The product is predominantly corundum, exhibiting high melting point, high strength, and high wear resistance. The high-temperature conversion and eutectic process, forming mullite and aluminum-chromium eutectic, imparts excellent thermal shock resistance and corrosion resistance. It is suitable as a refractory material for critical components such as kiln linings, kiln furniture, and insulation layers in high-temperature industries such as metallurgy and building materials, thereby extending their service life. Attached Figure Description

[0035] Figure 1 Typical microstructure of the multi-phase corundum-mullite brick of the present invention.

[0036] Figure 2 The image shows the XRD pattern of the multi-phase corundum-mullite brick of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solution will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0038] To further improve the performance of mullite to cope with more demanding application environments and extend its service life, as mentioned above, multi-phase mullite refractory materials have been developed in the prior art. Mullite itself has good mechanical properties and a low coefficient of thermal expansion, while zirconia, utilizing its phase transformation toughening mechanism, can improve the material's toughness, prevent crack propagation, and resist the erosion of molten slag and glass melt. The addition of chromium oxide can further improve the material's resistance to alkali metal corrosion. However, in practice, in areas with drastic temperature fluctuations, its corrosion resistance, thermal shock resistance, and high-temperature slag resistance sometimes do not meet expectations, and its performance still needs further improvement. Therefore, the purpose of this invention is to provide a multi-phase corundum-mullite refractory material that combines excellent corrosion resistance and thermal shock resistance, making it suitable for applications with large temperature variations within kilns and where the material is subject to erosion by molten slag or melt. The multi-phase corundum-mullite brick of this invention comprises, by weight percentage, 50-70% tabular corundum and white corundum, 5-20% andalusite, 3-5% chrome green, 0-10% fused chromium oxide sand, 5-20% zircon powder, and 1-10% calcined alumina powder, with the sum of the weight percentages of the above components being 100%. Tabular corundum is added in granular form, and its addition amount is not less than 20% of the total raw materials. White corundum is added in the form of graded granules and fine powder. This fully utilizes the role of corundum aggregate as the main crystalline phase, providing high-temperature strength, hardness, and corrosion resistance. The added andalusite can transform into mullite at high temperatures, and the decomposed silica and zircon powder can react with corundum, calcined alumina powder, etc., to generate mullite, zirconium dioxide, aluminum-chromium solid solution, etc., fully and synergistically exerting the effects of toughening and inhibiting microcrack development, not only ensuring high-temperature stability but also greatly improving thermal shock resistance. Figure 1 The microstructure of the multi-phase corundum-mullite brick of the present invention is shown. Figure 2The XRD pattern shows that the main phase structure is corundum, and it also contains composite phases such as mullite, aluminum-chromium solid solution, and zirconium dioxide. The addition of chromium oxide significantly improves erosion resistance. For the multi-phase corundum-mullite refractory material of this invention, the amount of chromium-aluminum or further fused chromium oxide can be added according to different erosion resistance requirements. When the amount of chromium green added is <5%, it is added in the form of fine powder. When the amount of chromium green added is 5%, the amount of fused chromium oxide added is 0-10%, which can further form phase structures such as chromium-aluminum solid solution. Specifically, the multi-phase corundum-mullite refractory material of this invention contains, by weight percentage, 5-10% tabular corundum particles with a particle size of 5-3 mm and 10-25% tabular corundum particles with a particle size of 3-1 mm. The composition comprises: 5-15% white fused alumina particles with a diameter of 3-1 mm, 10-20% white fused alumina particles with a diameter of 3-0.1 mm, and 10-15% fine white fused alumina powder with a diameter less than 74 μm. Also comprises: 5-15% andalusite particles with a diameter of 1-0.1 mm, and 3-15% fine andalusite powder with a diameter less than 74 μm. Additionally, it includes: 3-5% chrome green with a diameter less than 30 μm, 0-10% fused chromium oxide particles with a diameter of 1-0.1 mm, 3-15% fine zircon powder with a diameter less than 15 μm, and 1-10% calcined alumina powder with a diameter less than 15 μm. The total weight percentage of all components is 100%. The tabular fused alumina contains >99% Al₂O₃ and has a bulk density ≥3.5 g / cm³. 3 White fused alumina has an Al2O3 content >99% and a bulk density ≥3.5 g / cm³. 3 The calcined alumina powder has an Al2O3 content ≥99%. The andalusite has an Al2O3 content ≥57% and an Fe2O3 content ≤1.0%. The zircon has ZrO2+HfO2 ≥65%, SiO2 ≥32%, and Fe2O3 content ≤0.5%. The fused chromium oxide has a Cr2O3 content ≥99%, and the chromium green has a Cr2O3 content ≥99%.

[0039] The preparation method of the multi-composite phase corundum mullite brick of the present invention includes the following steps:

[0040] a. Weigh the raw materials according to the proportion, and place the white corundum fine powder, andalusite powder, fused chromium oxide powder, chrome green, desiliconized zirconium, and calcined alumina powder into a twin-helix premixer for premixing for no less than 30 minutes to obtain premixed powder;

[0041] b. Place the granular material in a high-strength mixer and mix for 1-10 minutes, then add the binder and mix for 3-5 minutes, then add the premixed powder from step a and mix for 10-30 minutes to obtain the mixture.

[0042] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton or 1000-ton press.

[0043] d. After drying, the formed brick blanks are fired at a high temperature of 1500-1600℃ and held for 8-12 hours to obtain multi-phase corundum mullite bricks.

[0044] The tabular corundum used in the following examples and comparative examples has an Al2O3 content of 99.31% and a bulk density of 3.53 g / m³. 3 The white fused alumina, with particle sizes of 5–3 mm and 3–1 mm, was purchased from Shandong Hengjia High-Purity Refractory Raw Materials Co., Ltd. The white fused alumina used had an Al₂O₃ content of 99.48% and a bulk density of 3.5 L / m³. 3 The following materials were purchased from Kaifeng Datong Refractory Materials Co., Ltd. Andalusite (Al₂O₃ 57.87%, Fe₂O₃ 0.97%, particle size 1-0.1mm and 200 mesh) was purchased from Gongyi Mingtai Refractory Materials Co., Ltd. Fused chromium oxide (Cr₂O₃ content 99.34%, 1-0.1mm) and chrome green (Cr₂O₃ content 99.54%, 500 mesh) were purchased from Luoyang Zhengjie Science & Technology Industry & Trade Co., Ltd. Zircon (ZrO₂+HfO₂ 67.3%, SiO₂ 33.4%, Fe₂O₃ 0.37%, 1000 mesh) was purchased from Sanxiang New Materials Co., Ltd. Calcined alumina powder (Al₂O₃ 99.31%, 1000 mesh) was purchased from Kaifeng Hecheng Inorganic Non-Further Materials Co., Ltd.

[0045] Example 1

[0046] The multi-phase corundum mullite brick of this embodiment is composed of the following components in weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5-3mm tabular corundum particles: 5%, 3-1mm tabular corundum particles: 15%, white corundum: 3-1mm particles: 15%, 1-0.1mm white corundum particles: 20%, 200-mesh white corundum powder: 10%, andalusite: 1-0.1mm particles: 5%, 200-mesh andalusite powder: 10%, chrome green: 3%, zircon powder: 10%, and alumina powder: 7%.

[0047] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0048] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 10 kg of andalusite, 3 kg of chrome green, 10 kg of zircon fine powder and 7 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0049] b. Place the remaining 60 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0050] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0051] d. After drying, the formed brick blanks are fired in a kiln at 1550°C and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this embodiment.

[0052] Example 2

[0053] The multi-phase corundum mullite brick of this embodiment is composed of the following components in weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5-3mm tabular corundum particles: 5%; 3-1mm tabular corundum particles: 25%; white corundum: 10% 3-1mm particles; 1-0.1mm white corundum particles: 15%; 200-mesh white corundum powder: 10%; andalusite: 7.5% 1-0.1mm particles; 200-mesh andalusite powder: 7.5%; chrome green: 5%; zircon powder: 10%; alumina powder: 5%.

[0054] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0055] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 7.5 kg of andalusite, 5 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0056] b. Place the remaining 62.5 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0057] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0058] d. After drying, the formed brick blanks are fired in a kiln at 1550°C and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this embodiment.

[0059] Example 3

[0060] The multi-phase corundum mullite brick of this embodiment is composed of the following components in weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5-3mm tabular corundum particles: 5%; 3-1mm tabular corundum particles: 15%; white corundum: 3-1mm particles: 20%; white corundum: 1-0.1mm particles: 15%; 200-mesh white corundum powder: 10%; andalusite: 1-0.1mm particles: 5%; 200-mesh andalusite powder: 10%; chrome green: 5%; zircon powder: 10%; alumina powder: 5%.

[0061] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0062] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 10 kg of andalusite, 5 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0063] b. Place the remaining 60 kg of granular raw materials into a high-strength mixer and mix for 3 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 20 minutes to obtain the mixture.

[0064] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0065] d. After drying, the formed brick blanks are fired in a kiln at 1550°C and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this embodiment.

[0066] Example 4

[0067] The multi-phase corundum mullite brick of this embodiment is composed of the following components in weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5-3mm tabular corundum particles: 5%; 3-1mm tabular corundum particles: 15%; 3-1mm white corundum particles: 20%; 1-0.1mm white corundum particles: 10%; 200-mesh white corundum powder: 10%; 1-0.1mm andalusite particles: 7.5%; 200-mesh andalusite powder: 7.5%; 1-0.1mm fused chromium oxide particles: 5%; chrome green: 5%; zircon powder: 10%; alumina powder: 5%.

[0068] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0069] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 7.5 kg of andalusite, 5 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0070] b. Place the remaining 62.5 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 15 minutes to obtain the mixture.

[0071] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0072] d. After drying, the formed brick blanks are fired in a kiln at 1550°C and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this embodiment.

[0073] Example 5

[0074] The multi-phase corundum mullite brick of this embodiment is composed of the following components in weight percentages, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5% tabular corundum 5-3mm particles, 25% tabular corundum 3-1mm particles, 5% white corundum 3-1mm particles, 10% white corundum 1-0.1mm particles, 10% white corundum 200-mesh fine powder, 10% andalusite 1-0.1mm particles, 10% andalusite 200-mesh fine powder, 5% fused chromium oxide 1-0.1mm particles, 5% chrome green, 10% zircon fine powder, and 5% alumina fine powder.

[0075] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0076] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 10 kg of andalusite, 5 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0077] b. Place the remaining 60 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 15 minutes to obtain the mixture.

[0078] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0079] d. After drying, the formed brick blanks are fired in a kiln at 1550°C and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this embodiment.

[0080] Comparative Example 1

[0081] This comparative example of a multi-phase corundum brick consists of the following components in weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) of the total weight of the following components: 5-3mm tabular corundum particles: 15%; 3-1mm tabular corundum particles: 25%; white corundum: 3-1mm particles: 10%; white corundum: 1-0.1mm particles: 15%; 200-mesh white corundum powder: 10%; chrome green: 10%; desilicationized zirconium powder (ZrO2>99%): 10%; alumina powder: 5%.

[0082] The preparation method of the above-mentioned multi-phase corundum brick includes the following steps:

[0083] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 10 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0084] b. Place the remaining 65 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0085] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0086] d. After drying, the formed brick blanks are fired in a kiln at 1550℃ and held for 10 hours to obtain the multi-phase corundum bricks of this comparative example.

[0087] Comparative Example 2

[0088] This comparative example of a multi-phase corundum mullite brick is composed of the following components by weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) by weight of the total components: 5% tabular corundum 5–3 mm particles, 25% tabular corundum 3–1 mm particles, 10% white corundum 3–1 mm particles, 15% white corundum 1–0.1 mm particles, 10% white corundum 200 mesh fine powder, 7.5% andalusite 1–0.1 mm particles, 7.5% andalusite 200 mesh fine powder, 5% chrome green, 10% desilicationized zirconium fine powder (ZrO2>99%), and 5% alumina fine powder.

[0089] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0090] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 7.5 kg of andalusite, 5 kg of chrome green, 10 kg of desilicationized zirconium fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0091] b. Place the remaining 62.5 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0092] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press;

[0093] d. After drying, the formed brick blanks are fired in a kiln at 1550℃ and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this comparative example.

[0094] Comparative Example 3

[0095] This comparative example of a multi-phase corundum mullite brick is composed of the following components by weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) by weight of the total components: 5-3mm tabular corundum particles: 15%; 3-1mm tabular corundum particles: 25%; white corundum: 3-1mm particles: 10%; white corundum: 1-0.1mm particles: 15%; 200-mesh white corundum powder: 10%; chrome green: 5%; zircon powder: 10%; alumina powder: 10%.

[0096] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0097] a. Weigh the raw materials according to the above proportions. Place 10 kg of white corundum, 5 kg of chrome green, 10 kg of zircon fine powder and 10 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0098] b. Place the remaining 65 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0099] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press.

[0100] After drying, the shaped brick blanks were fired in a kiln at 1550℃ and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this comparative example.

[0101] Comparative Example 4

[0102] This comparative example of a multi-phase corundum mullite brick is composed of the following components by weight percentage, plus 3.2% aluminum dihydrogen phosphate (specific gravity 1.38) by weight of the total components: white corundum 5-3mm particles: 25%, white corundum 3-1mm particles: 25%, tabular corundum 1-0.1mm particles: 5%, tabular corundum 200-mesh fine powder: 10%, andalusite 1-0.1mm particles: 7.5%, andalusite 200-mesh fine powder: 7.5%, chrome green: 5%, zircon fine powder: 10%, and alumina fine powder: 5%.

[0103] The preparation method of the above-mentioned multi-phase corundum-mullite bricks includes the following steps:

[0104] a. Weigh the raw materials according to the above proportions. Place 10 kg of tabular corundum, 7.5 kg of andalusite, 5 kg of chrome green, 10 kg of zircon fine powder and 5 kg of calcined alumina powder into a double helix premixer and premix for 35 minutes to obtain premixed powder.

[0105] b. Place the remaining 62.5 kg of granular raw materials into a high-strength mixer and mix for 2 minutes. Then add 3.2 kg of aluminum dihydrogen phosphate and mix for 4 minutes. Finally, add the premixed powder from step a and mix for 12 minutes to obtain the mixture.

[0106] c. Add the mixture obtained in step b into the assembled mold, and press it into brick blanks using a 630-ton press.

[0107] After drying, the shaped brick blanks were fired in a kiln at 1550℃ and held for 10 hours to obtain the multi-phase corundum-mullite bricks of this comparative example.

[0108] The sample bricks prepared in the above embodiments and comparative examples were tested according to the testing standards for dense refractory materials for room temperature compressive strength, load softening temperature of 0.2 MPa, high temperature flexural strength (1400℃×0.5h), and thermal shock resistance (1100℃ water cooling). The results are shown in Table 1 below.

[0109] Table 1

[0110]

[0111] A static crucible method was used. Crucibles with a diameter of Φ50mm × 50mm were prepared using the refractory materials of Example 2 and Comparative Examples 1-4. 25g of RH refining slag with a particle size less than 0.5mm was placed inside the crucible and then placed in an electric furnace. The furnace was heated to 1650℃ at a heating rate of 5℃ / min and held for 3 hours. This cycle was repeated 5 times. The maximum penetration depth was then measured by longitudinally cutting the crucible. The results are shown in Table 2 below.

[0112] Table 2

[0113] Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Maximum depth of the permeable layer (mm) 4.8 8.6 6.9 7.5 6.3

[0114] The above description is merely a preferred embodiment of the present invention. The features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the principles of the present invention, and any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A multi-phase corundum-mullite brick, characterized in that: It is prepared by adding a binder to the following components and firing at a high temperature of 1500-1600℃, wherein: Plate-shaped corundum particles with a diameter of 5-3 mm, 5-10%; Particles with a diameter of 3–1 mm, 10–25%; White corundum particles with a diameter of 3-1 mm, 5-15%; Particles with a diameter of 1–0.1 mm, 10–20%; Fine powder with a particle size of less than 74μm, 10-15%; andalusite particles with a diameter of 1–0.1 mm, accounting for 5–15%; Fine powder with a particle size of less than 74μm, 3-15%; Chromium green fine powder with a particle size of less than 30 μm, 3-5%; Electrofused chromium oxide particles with a diameter of 1–0.1 mm, 0–10%; Zircon powder with a particle size of less than 15μm, 5-20%; 1-10% of fine powder of calcined alumina with a particle size of less than 15μm; The sum of the weight percentages of the above components is 100%.

2. The multi-phase corundum-mullite brick according to claim 1, characterized in that: The composite addition of tabular corundum and white corundum is 60-75%, andalusite is 10-25%, chrome green is 3-5%, fused chromium oxide sand is 0-10%, zircon is 5-20%, and calcined alumina powder is 1-10%, and the sum of the weight percentages of the above components is 100%.

3. The multi-phase corundum-mullite brick according to claim 2, characterized in that: The composite addition of tabular corundum and white corundum is 60-75%, andalusite is 10-20%, chrome green is 3-5%, fused chromium oxide sand is 0-10%, zircon is 5-15%, and calcined alumina powder is 1-5%, and the sum of the weight percentages of the above components is 100%.

4. The multi-phase corundum-mullite brick according to any one of claims 1-3, characterized in that: When the amount of chrome green added is less than 5%, the fused chromium oxide is not added; when the amount of chrome green added is 5%, the amount of fused chromium oxide added is 0-10%.

5. The multi-phase corundum-mullite brick according to claim 4, characterized in that: The tabular corundum has an Al2O3 content >99% and a bulk density ≥3.5 g / cm³. 3 White fused alumina has an Al2O3 content >99% and a bulk density ≥3.5 g / cm³. 3 The calcined alumina powder has an Al2O3 content of ≥99%.

6. The multi-phase corundum-mullite brick according to claim 4, characterized in that: The andalusite contains ≥57% Al2O3 and ≤1.0% Fe2O3.

7. The multi-phase corundum-mullite brick according to claim 4, characterized in that: The zircon contains ZrO2+HfO2≥65%, SiO2≥32%, and Fe2O3 content≤0.5%.

8. The multi-phase corundum-mullite brick according to claim 4, characterized in that: The fused chromium oxide contains ≥99% Cr2O3, and the chromium green contains ≥99% Cr2O3.

9. The method for preparing multi-phase corundum-mullite bricks according to any one of claims 1-8, characterized in that... Includes the following steps: a. Weigh each raw material according to the component ratio of the above claims, place the fine powder of each raw material in a premixer for premixing for a time of not less than 30 minutes, and obtain premixed powder; b. Place the granules of each raw material in a mixer and mix them, then add a binder and mix, then add the premixed powder from step a and mix to obtain a mixture. c. Add the mixture obtained in step b into the assembled mold and press it to form a brick blank; d. After drying, the formed brick blanks are fired at a high temperature of 1500-1600℃ and held for 8-12 hours to obtain the multi-composite phase corundum mullite bricks.

10. The method for preparing multi-phase corundum-mullite bricks according to claim 9, characterized in that: The binder is aluminum dihydrogen phosphate, and the amount added is 3-5% of the total weight of the above raw materials.

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