Refractory brick and method of making same

Abstract

This invention belongs to the field of refractory material preparation technology, specifically relating to a refractory brick and its preparation method. The refractory brick of this invention uses calcined bauxite and fused white corundum as the main raw materials, providing a high-strength refractory skeleton to ensure the basic compressive strength of the refractory brick. The addition of kyanite and andalusite, through a kyanite-andalusite composite, achieves gradient control of the expansion rate; kyanite rapidly responds to mid-temperature shrinkage, while andalusite sustains high-temperature expansion, synergistically achieving volume stability. Secondary alumina ash, hematite tailings, and serpentine tailings are also added to the raw materials to promote the formation of magnesium iron spinel and mullite phases; lanthanum oxide, yttrium aluminum garnet, titanium silicon carbide, and yttrium titanate are added to further improve the strength and crack resistance of the refractory brick; calcium hexaaluminate micron powder, p-Al2O3 micron powder, and deionized water are used as composite binders. Thus, the synergistic effect between the raw materials ensures that the prepared refractory brick has excellent strength and crack resistance.

Description

Technical Field

[0001] This invention belongs to the field of refractory material preparation technology, specifically relating to a refractory brick and its preparation method. Background Technology

[0002] Refractory materials are essential basic materials in the industrial field. Currently, refractory materials are required for industrial furnaces and kilns in steel smelting, coking, and mechanical heat treatment systems, as well as their linings. Large quantities of refractory bricks are needed for the interior and lining of these furnaces. Most existing refractory bricks are clay-based insulating refractory bricks, primarily composed of mullite, glass phase, cristobalite, and quartz. They are typically made from hard clay, pre-calcined into clinker, then mixed with soft clay and molded using semi-dry or plastic methods, and fired at 1300-1400℃ to produce clay brick products. Small amounts of water glass, cement, and other binders can also be added to create unfired products and amorphous materials, mainly used in blast furnaces, hot blast stoves, heating furnaces, power boilers, lime kilns, rotary kilns, glass kilns, and ceramic and refractory brick firing kilns.

[0003] Patent CN201210520207.2 discloses a composite thermal shock resistant high-alumina refractory brick and its preparation method. The formula is reasonable, the cost is relatively low, and the preparation method is simple and easy to operate. The thermal shock stability of the fired refractory brick is greatly improved, extending the service life of the hot blast stove and improving the economic benefits for enterprises. However, the refractory brick in this patent does not possess high strength and cannot solve the problem of cracking during use.

[0004] Therefore, in view of the problems of insufficient strength and easy cracking of refractory bricks currently on the market, it is necessary to explore a new type of refractory brick. Summary of the Invention

[0005] The purpose of this invention is to provide a refractory brick with high strength and resistance to cracking. In addition, this invention also provides a method for its preparation.

[0006] The refractory brick of the present invention is composed of the following raw materials in parts by weight: 43-45 parts calcined bauxite, 3.3-3.5 parts kyanite, 2-3 parts andalusite, 16-18 parts fused white corundum, 5-6 parts secondary alumina, 7-8 parts hematite tailings, 5-6 parts serpentine tailings, 1.2-1.5 parts lanthanum oxide, 2.0-3.0 parts yttrium aluminum garnet, 1.8-2.5 parts silicon carbide, 1.3-1.5 parts yttrium titanate, 3.0-4.0 parts p-Al₂O₃ micro powder, 1.8-2.2 parts calcium hexaaluminate micro powder, and 1.5-2.0 parts deionized water.

[0007] The secondary aluminum ash, by mass percentage, has the following chemical composition: Al2O3 83.54%, MgO 8.99%, SiO2 1.21%, K2O 0.75%, Na2O 1.83%, CaO 0.48%, TiO2 0.20%, Fe2O3 0.24%, and loss on ignition 2.76%.

[0008] The serpentine tailings, by mass percentage, have the following chemical composition: MgO 37.27%, SiO2 40.86%, TFe 8.64%, Al2O3 2.23%, CaO 1.42%, and loss on ignition 9.58%.

[0009] The hematite tailings, by mass percentage, have the following chemical composition: Fe2O3 45.28%, SiO2 26.40%, Al2O3 12.59%, CaO 2.20%, MgO 1.29%, P2O5 2.95%, K2O 0.81%, TiO2 0.52%, Na2O 0.22%, MnO 0.28%, and loss on ignition 7.46%.

[0010] The method for preparing refractory bricks according to the present invention comprises the following steps: (1) Place the secondary aluminum ash in hot water at 80-90℃ and stir for 3.5-4h. After vacuum filtration, wash with water 3 times and then dry at 110℃ for 3.5-4h. Crush and pass through a 200-mesh sieve to prepare pretreated secondary aluminum ash. (2) The pretreated secondary aluminum ash, calcined bauxite, kyanite, andalusite, fused white corundum, hematite tailings, serpentine tailings, lanthanum oxide, yttrium aluminum garnet, yttrium titanate, titanium silicon carbide, p-Al2O3 micro powder and calcium hexaaluminate micro powder prepared in step (1) are added to the mixer and dry-mixed evenly. (3) Spray deionized water into the mixture prepared in step (2) and mix evenly to obtain mud. Pack the mud into a sealed bag for curing. (4) The clay material after being trapped in step (3) is placed into a mold and dry-pressed to obtain a green body; (5) The green body is dried, sintered at high temperature, and finally cooled to room temperature in the furnace to prepare refractory bricks.

[0011] In step (1), the mass ratio of secondary aluminum ash to hot water is 1:6.

[0012] In step (2), the dry mixing temperature is room temperature and the dry mixing time is 15-20 min.

[0013] In step (3), the wet mixing temperature is room temperature and the wet mixing time is 20-23 min.

[0014] In step (3), the material is trapped at room temperature for 24-26 hours.

[0015] In step (4), the pressure for dry pressing is 220 MPa and the time for dry pressing is 25 s.

[0016] The drying process described in step (5) involves first allowing the product to stand naturally at room temperature for 6 hours, then drying it at a constant temperature of 60°C for 12 hours, and finally drying it at a constant temperature of 110°C for 8 hours.

[0017] The sintering described in step (5) is carried out under a nitrogen atmosphere by first heating from room temperature to 300-320℃ at a heating rate of 1.5℃ / min, then heating from 300-320℃ to 800-810℃ at a heating rate of 3℃ / min, then heating from 800-810℃ to 1350-1360℃ at a heating rate of 2.0℃ / min, and finally heating from 1350-1360℃ to 1510-1530℃ at a heating rate of 2.0℃ / min and holding at that temperature for 3 hours.

[0018] Compared with the prior art, the present invention has the following advantages: (1) The refractory bricks of the present invention use calcined bauxite and fused white corundum as the main raw materials to provide a high-strength refractory skeleton for the refractory bricks, ensuring the basic compressive strength of the refractory bricks. Kyanite and andalusite are added, and the kyanite-andalusite compound realizes the gradient control of the expansion rate. Kyanite responds quickly to the mid-temperature shrinkage, and andalusite continues the high-temperature expansion, thus achieving volume stability in synergy. Secondary alumina ash, hematite tailings and serpentine tailings are also added to the raw materials to promote the formation of magnesium iron spinel and mullite phases; lanthanum oxide, yttrium aluminum garnet, titanium silicon carbide and yttrium titanate are added to further improve the strength and crack resistance of the refractory bricks; calcium hexaaluminate micro powder, p-Al2O3 micro powder and deionized water are used as composite binders; thus, the synergistic effect between the raw materials ensures that the prepared refractory bricks have excellent strength and crack resistance.

[0019] (2) The refractory bricks of the present invention exhibit a synergistic effect among secondary alumina ash, hematite tailings, and serpentine tailings. Specifically, the active MgO in the serpentine tailings reacts with the active Fe2O3 in the hematite tailings to generate MgFe2O4 spinel in situ at high temperature. This phase is both a high-strength phase and a micro-expansion, crack-resistant phase. The active Al2O3 in the secondary alumina ash reacts with silica in other raw materials (kyanite, andalusite) to generate mullite in situ, which fills the gaps between aggregates and increases density. Thus, the density and strength of the refractory bricks are improved by introducing waste tailings.

[0020] (3) The refractory brick of the present invention uses lanthanum oxide, yttrium aluminum garnet, titanium silicon carbide (Ti3SiC2), and yttrium titanate as fillers. The four components work synergistically to further improve the strength and crack resistance of the refractory brick. Lanthanum oxide agglomerates at the grain boundaries of magnesium iron spinel to form a grain boundary barrier layer, and reacts with alumina in the raw material to generate lanthanum aluminate grain boundary pinning phase, which inhibits abnormal growth of spinel grains; at the same time, lanthanum oxide reacts with iron oxide to generate lanthanum ferrite, which stabilizes the iron phase and reduces thermal stress cracking. Yttrium aluminum garnet and yttrium titanate work synergistically. Yttrium aluminum garnet, with its good thermal expansion matching with corundum and high-temperature chemical stability, fills the grain boundaries to eliminate pores and relieve thermal cycling stress; yttrium titanate, with its high-temperature chemical inertness, further stabilizes the grain boundary structure, hinders grain boundary dislocation movement, and improves the high-temperature creep resistance of the refractory brick. Under a nitrogen atmosphere, the layered crystal structure of titanium silicon carbide exhibits crack deflection, lamellar pull-out, and interlaminar slip toughening effects, actively inhibiting crack propagation and significantly improving fracture toughness and thermal shock resistance, thus solving the brittleness problem of refractory bricks. Therefore, the synergistic effect between the raw materials ensures the strength and crack resistance of the prepared refractory bricks.

[0021] (4) The refractory brick of the present invention uses a compound of calcium hexaaluminate micro powder, p-Al2O3 micro powder and deionized water as a binder. At room temperature, the hydrated alumina gel formed by p-Al2O3 in water provides the green body bonding strength and ensures the molding performance. During high-temperature sintering, the hydrated phase dehydrates and transforms into active alumina, which undergoes a solid-phase sintering reaction with calcium hexaaluminate to form a continuous, high-melting-point corundum-calcium hexaaluminate ceramic network. This avoids the generation of low-melting-point glass phase and further offsets the matrix sintering shrinkage through the micro-expansion effect of calcium hexaaluminate, achieving a stable bond with high strength, high temperature resistance and no cracking.

[0022] (5) The method for preparing refractory bricks described in this invention involves adding a large amount of solid waste to the raw materials, which helps to alleviate environmental pressure. The preparation process is simple, the parameters are easy to control, and the performance of the prepared refractory bricks is stable. Detailed Implementation

[0023] Example 1

[0024] The refractory brick described in Example 1 is composed of the following raw materials by weight: 44 parts calcined bauxite, 3.4 parts kyanite, 2.5 parts andalusite, 17 parts fused white corundum, 5.5 parts secondary alumina, 7.5 parts hematite tailings, 5.5 parts serpentine tailings, 1.3 parts lanthanum oxide, 2.5 parts yttrium aluminum garnet, 2.1 parts silicon carbide, 1.4 parts yttrium titanate, 3.5 parts p-Al₂O₃ micro powder, 2.0 parts calcium hexaaluminate micro powder, and 1.7 parts deionized water.

[0025] The secondary aluminum ash, by mass percentage, has the following chemical composition: Al2O3 83.54%, MgO 8.99%, SiO2 1.21%, K2O 0.75%, Na2O 1.83%, CaO 0.48%, TiO2 0.20%, Fe2O3 0.24%, and loss on ignition 2.76%.

[0026] The serpentine tailings, by mass percentage, have the following chemical composition: MgO 37.27%, SiO2 40.86%, TFe 8.64%, Al2O3 2.23%, CaO 1.42%, and loss on ignition 9.58%.

[0027] The hematite tailings, by mass percentage, have the following chemical composition: Fe2O3 45.28%, SiO2 26.40%, Al2O3 12.59%, CaO 2.20%, MgO 1.29%, P2O5 2.95%, K2O 0.81%, TiO2 0.52%, Na2O 0.22%, MnO 0.28%, and loss on ignition 7.46%.

[0028] The method for preparing refractory bricks described in Example 1 consists of the following steps: (1) The secondary aluminum ash was placed in hot water at 85℃ and stirred for 3.7h. After vacuum filtration, it was washed with water 3 times and then dried at 110℃ for 3.7h. It was then crushed and passed through a 200-mesh sieve to prepare the pretreated secondary aluminum ash. (2) The pretreated secondary aluminum ash, calcined bauxite, kyanite, andalusite, fused white corundum, hematite tailings, serpentine tailings, lanthanum oxide, yttrium aluminum garnet, yttrium titanate, titanium silicon carbide, p-Al2O3 micro powder and calcium hexaaluminate micro powder prepared in step (1) are added to the mixer and dry-mixed evenly. (3) Spray deionized water into the mixture prepared in step (2) and mix evenly to obtain mud. Pack the mud into a sealed bag for curing. (4) The clay material after being trapped in step (3) is placed into a mold and dry-pressed to obtain a green body; (5) The green body is dried, sintered at high temperature, and finally cooled to room temperature in the furnace to prepare refractory bricks.

[0029] In step (1), the mass ratio of secondary aluminum ash to hot water is 1:6.

[0030] In step (2), the dry mixing temperature is room temperature and the dry mixing time is 17 min.

[0031] In step (3), the wet mixing temperature is room temperature and the wet mixing time is 22 min.

[0032] In step (3), the material is trapped at room temperature for 25 hours.

[0033] In step (4), the pressure for dry pressing is 220 MPa and the time for dry pressing is 25 s.

[0034] The drying process described in step (5) involves first allowing the product to stand naturally at room temperature for 6 hours, then drying it at a constant temperature of 60°C for 12 hours, and finally drying it at a constant temperature of 110°C for 8 hours.

[0035] The sintering described in step (5) is carried out under a nitrogen atmosphere by first heating from room temperature to 310°C at a heating rate of 1.5°C / min, then heating from 310°C to 805°C at a heating rate of 3°C / min, then heating from 805°C to 1355°C at a heating rate of 2.0°C / min, and finally heating from 1355°C to 1520°C at a heating rate of 2.0°C / min and holding at that temperature for 3 hours. Example 2

[0036] The refractory brick described in Example 2 is composed of the following raw materials by weight: 43 parts calcined bauxite, 3.3 parts kyanite, 2 parts andalusite, 18 parts fused white corundum, 6 parts secondary aluminum ash, 7 parts hematite tailings, 5 parts serpentine tailings, 1.2 parts lanthanum oxide, 2.0 parts yttrium aluminum garnet, 1.8 parts silicon carbide, 1.5 parts yttrium titanate, 4.0 parts p-Al2O3 micro powder, 1.8 parts calcium hexaaluminate micro powder, and 1.5 parts deionized water.

[0037] The secondary aluminum ash, by mass percentage, has the following chemical composition: Al2O3 83.54%, MgO 8.99%, SiO2 1.21%, K2O 0.75%, Na2O 1.83%, CaO 0.48%, TiO2 0.20%, Fe2O3 0.24%, and loss on ignition 2.76%.

[0038] The serpentine tailings, by mass percentage, have the following chemical composition: MgO 37.27%, SiO2 40.86%, TFe 8.64%, Al2O3 2.23%, CaO 1.42%, and loss on ignition 9.58%.

[0039] The hematite tailings, by mass percentage, have the following chemical composition: Fe2O3 45.28%, SiO2 26.40%, Al2O3 12.59%, CaO 2.20%, MgO 1.29%, P2O5 2.95%, K2O 0.81%, TiO2 0.52%, Na2O 0.22%, MnO 0.28%, and loss on ignition 7.46%.

[0040] The method for preparing refractory bricks described in Example 2 consists of the following steps: (1) The secondary aluminum ash was placed in hot water at 90℃ and stirred for 3.5h. After vacuum filtration, it was washed with water 3 times and then dried at 110℃ for 3.5h. It was then crushed and passed through a 200-mesh sieve to prepare the pretreated secondary aluminum ash. (2) The pretreated secondary aluminum ash, calcined bauxite, kyanite, andalusite, fused white corundum, hematite tailings, serpentine tailings, lanthanum oxide, yttrium aluminum garnet, yttrium titanate, titanium silicon carbide, p-Al2O3 micro powder and calcium hexaaluminate micro powder prepared in step (1) are added to the mixer and dry-mixed evenly. (3) Spray deionized water into the mixture prepared in step (2) and mix evenly to obtain mud. Pack the mud into a sealed bag for curing. (4) The clay material after being trapped in step (3) is placed into a mold and dry-pressed to obtain a green body; (5) The green body is dried, sintered at high temperature, and finally cooled to room temperature in the furnace to prepare refractory bricks.

[0041] In step (1), the mass ratio of secondary aluminum ash to hot water is 1:6.

[0042] In step (2), the dry mixing temperature is room temperature and the dry mixing time is 15 min.

[0043] In step (3), the wet mixing temperature is room temperature and the wet mixing time is 20 min.

[0044] In step (3), the material temperature is room temperature and the material is trapped for 24 hours.

[0045] In step (4), the pressure for dry pressing is 220 MPa and the time for dry pressing is 25 s.

[0046] The drying process described in step (5) involves first allowing the product to stand naturally at room temperature for 6 hours, then drying it at a constant temperature of 60°C for 12 hours, and finally drying it at a constant temperature of 110°C for 8 hours.

[0047] The sintering described in step (5) is carried out under a nitrogen atmosphere by first heating from room temperature to 300°C at a heating rate of 1.5°C / min, then heating from 300°C to 800°C at a heating rate of 3°C / min, then heating from 800°C to 1350°C at a heating rate of 2.0°C / min, and finally heating from 1350°C to 1510°C at a heating rate of 2.0°C / min and holding at that temperature for 3 hours. Example 3

[0048] The refractory brick described in Example 3 is composed of the following raw materials by weight: 45 parts calcined bauxite, 3.5 parts kyanite, 3 parts andalusite, 16 parts fused white corundum, 5 parts secondary alumina, 8 parts hematite tailings, 6 parts serpentine tailings, 1.5 parts lanthanum oxide, 3.0 parts yttrium aluminum garnet, 2.5 parts silicon carbide, 1.3 parts yttrium titanate, 3.0 parts p-Al2O3 micro powder, 2.2 parts calcium hexaaluminate micro powder, and 2.0 parts deionized water.

[0049] The secondary aluminum ash, by mass percentage, has the following chemical composition: Al2O3 83.54%, MgO 8.99%, SiO2 1.21%, K2O 0.75%, Na2O 1.83%, CaO 0.48%, TiO2 0.20%, Fe2O3 0.24%, and loss on ignition 2.76%.

[0050] The serpentine tailings, by mass percentage, have the following chemical composition: MgO 37.27%, SiO2 40.86%, TFe 8.64%, Al2O3 2.23%, CaO 1.42%, and loss on ignition 9.58%.

[0051] The hematite tailings, by mass percentage, have the following chemical composition: Fe2O3 45.28%, SiO2 26.40%, Al2O3 12.59%, CaO 2.20%, MgO 1.29%, P2O5 2.95%, K2O 0.81%, TiO2 0.52%, Na2O 0.22%, MnO 0.28%, and loss on ignition 7.46%.

[0052] The method for preparing refractory bricks described in Example 3 consists of the following steps: (1) The secondary aluminum ash was placed in hot water at 80℃ and stirred for 4 hours. After vacuum filtration, it was washed 3 times with water and then dried at 110℃ for 4 hours. It was then crushed and passed through a 200-mesh sieve to prepare the pretreated secondary aluminum ash. (2) The pretreated secondary aluminum ash, calcined bauxite, kyanite, andalusite, fused white corundum, hematite tailings, serpentine tailings, lanthanum oxide, yttrium aluminum garnet, yttrium titanate, titanium silicon carbide, p-Al2O3 micro powder and calcium hexaaluminate micro powder prepared in step (1) are added to the mixer and dry-mixed evenly. (3) Spray deionized water into the mixture prepared in step (2) and mix evenly to obtain mud. Pack the mud into a sealed bag for curing. (4) The clay material after being trapped in step (3) is placed into a mold and dry-pressed to obtain a green body; (5) The green body is dried, sintered at high temperature, and finally cooled to room temperature in the furnace to prepare refractory bricks.

[0053] In step (1), the mass ratio of secondary aluminum ash to hot water is 1:6.

[0054] In step (2), the dry mixing temperature is room temperature and the dry mixing time is 20 min.

[0055] In step (3), the wet mixing temperature is room temperature and the wet mixing time is 23 min.

[0056] In step (3), the material temperature is room temperature and the material is trapped for 26 hours.

[0057] In step (4), the pressure for dry pressing is 220 MPa and the time for dry pressing is 25 s.

[0058] The drying process described in step (5) involves first allowing the product to stand naturally at room temperature for 6 hours, then drying it at a constant temperature of 60°C for 12 hours, and finally drying it at a constant temperature of 110°C for 8 hours.

[0059] The sintering described in step (5) is carried out under a nitrogen atmosphere by first heating from room temperature to 320°C at a heating rate of 1.5°C / min, then heating from 320°C to 810°C at a heating rate of 3°C / min, then heating from 810°C to 1360°C at a heating rate of 2.0°C / min, and finally heating from 1360°C to 1530°C at a heating rate of 2.0°C / min and holding at that temperature for 3 hours.

[0060] Comparative Example 1 The preparation method of the refractory brick described in Comparative Example 1 is the same as that in Example 1, the only difference being the composition of the raw materials. The refractory brick described in Comparative Example 1, by weight, consists of the following raw materials: 44 parts calcined bauxite, 3.4 parts kyanite, 2.5 parts andalusite, 17 parts fused white corundum, 5.5 parts secondary alumina, 7.5 parts hematite tailings, 5.5 parts serpentine tailings, 2.5 parts yttrium aluminum garnet, 2.1 parts silicon carbide, 1.4 parts yttrium titanate, 3.5 parts p-Al₂O₃ micro powder, 2.0 parts calcium hexaaluminate micro powder, and 1.7 parts deionized water.

[0061] Comparative Example 2 The preparation method of the refractory bricks described in Comparative Example 2 is the same as that in Example 1, the only difference being the composition of the raw materials. The refractory bricks described in Comparative Example 2, by weight, consist of the following raw materials: 44 parts calcined bauxite, 3.4 parts kyanite, 2.5 parts andalusite, 17 parts fused white corundum, 5.5 parts secondary alumina, 7.5 parts hematite tailings, 5.5 parts serpentine tailings, 1.3 parts lanthanum oxide, 2.1 parts silicon carbide titanium, 3.5 parts p-Al₂O₃ micro powder, 2.0 parts calcium hexaaluminate micro powder, and 1.7 parts deionized water.

[0062] Comparative Example 3 The preparation method of the refractory brick described in Comparative Example 3 is the same as that in Example 1, the only difference being the composition of the raw materials. The refractory brick described in Comparative Example 3, by weight, consists of the following raw materials: 44 parts calcined bauxite, 3.4 parts kyanite, 2.5 parts andalusite, 17 parts fused white corundum, 5.5 parts secondary alumina, 7.5 parts hematite tailings, 5.5 parts serpentine tailings, 1.3 parts lanthanum oxide, 2.5 parts yttrium aluminum garnet, 1.4 parts yttrium titanate, 3.5 parts p-Al₂O₃ micro powder, 2.0 parts calcium hexaaluminate micro powder, and 1.7 parts deionized water.

[0063] The refractory bricks prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The room temperature compressive strength was tested according to GB / T5072-2023 "Test Method for Room Temperature Compressive Strength of Refractory Materials"; the high temperature flexural strength was tested according to GB / T 3002-2017 "Test Method for High Temperature Flexural Strength of Refractory Materials"; and the thermal shock resistance was tested according to GB / T 30873-2014 "Test Method for Thermal Shock Resistance of Refractory Materials". The test method was the water quenching method: the sample was held at 1100℃ for 15 min, then immersed in flowing water at 25℃ for 3 min to cool, and this process was repeated, recording the number of cycles at which the first crack appeared. The results are shown in Table 1 below. Table 1 Test Results of Refractory Brick Performance As shown in Table 1, the refractory bricks prepared in Examples 1-3 have significantly better performance than those in Comparative Examples 1-3. The performance of the refractory bricks prepared in Comparative Examples 1-3 is reduced due to the absence of any of the components, such as lanthanum oxide, yttrium aluminum garnet, yttrium titanate, and titanium silicon carbide.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A refractory brick, characterized in that: By weight, it is composed of the following raw materials: calcined bauxite 43-45 parts, kyanite 3.3-3.5 parts, andalusite 2-3 parts, fused white corundum 16-18 parts, secondary aluminum ash 5-6 parts, hematite tailings 7-8 parts, serpentine tailings 5-6 parts, lanthanum oxide 1.2-1.5 parts, yttrium aluminum garnet 2.0-3.0 parts, titanium silicon carbide 1.8-2.5 parts, yttrium titanate 1.3-1.5 parts, p-Al2O3 micro powder 3.0-4.0 parts, calcium hexaaluminate micro powder 1.8-2.2 parts, and deionized water 1.5-2.0 parts.

2. The refractory brick according to claim 1, characterized in that: The secondary aluminum ash, by mass percentage, has the following chemical composition: Al2O3 83.54%, MgO 8.99%, SiO2 1.21%, K2O 0.75%, Na2O 1.83%, CaO 0.48%, TiO2 0.20%, Fe2O3 0.24%, and loss on ignition 2.76%.

3. The refractory brick according to claim 1, characterized in that: The serpentine tailings, by mass percentage, have the following chemical composition: MgO 37.27%, SiO2 40.86%, TFe 8.64%, Al2O3 2.23%, CaO 1.42%, and loss on ignition 9.58%.

4. The refractory brick according to claim 1, characterized in that: The hematite tailings, by mass percentage, have the following chemical composition: Fe2O3 45.28%, SiO2 26.40%, Al2O3 12.59%, CaO 2.20%, MgO 1.29%, P2O5 2.95%, K2O 0.81%, TiO2 0.52%, Na2O 0.22%, MnO 0.28%, and loss on ignition 7.46%.

5. A method for preparing the refractory brick according to claim 1, characterized in that: It consists of the following steps: (1) Place the secondary aluminum ash in hot water at 80-90℃ and stir for 3.5-4h. After vacuum filtration, wash with water 3 times and then dry at 110℃ for 3.5-4h. Crush and pass through a 200-mesh sieve to prepare pretreated secondary aluminum ash. (2) The pretreated secondary aluminum ash, calcined bauxite, kyanite, andalusite, fused white corundum, hematite tailings, serpentine tailings, lanthanum oxide, yttrium aluminum garnet, yttrium titanate, titanium silicon carbide, p-Al2O3 micro powder and calcium hexaaluminate micro powder prepared in step (1) are added to the mixer and dry-mixed evenly. (3) Spray deionized water into the mixture prepared in step (2) and mix evenly to obtain mud. Pack the mud into a sealed bag for curing. (4) The clay material after being trapped in step (3) is placed into a mold and dry-pressed to obtain a green body; (5) The green body is dried, sintered at high temperature, and finally cooled to room temperature in the furnace to prepare refractory bricks.

6. The method for preparing refractory bricks according to claim 1, characterized in that: In step (1), the mass ratio of secondary aluminum ash to hot water is 1:6; In step (2), the dry mixing temperature is room temperature and the dry mixing time is 15-20 min.

7. The method for preparing refractory bricks according to claim 1, characterized in that: In step (3), the wet mixing temperature is room temperature and the wet mixing time is 20-23 min; In step (3), the material is trapped at room temperature for 24-26 hours.

8. The method for preparing refractory bricks according to claim 1, characterized in that: In step (4), the pressure for dry pressing is 220 MPa and the time for dry pressing is 25 s.

9. The method for preparing refractory bricks according to claim 1, characterized in that: The drying process described in step (5) involves first allowing the product to stand naturally at room temperature for 6 hours, then drying it at a constant temperature of 60°C for 12 hours, and finally drying it at a constant temperature of 110°C for 8 hours.

10. The method for preparing refractory bricks according to claim 1, characterized in that: The sintering described in step (5) is carried out under a nitrogen atmosphere by first heating from room temperature to 300-320℃ at a heating rate of 1.5℃ / min, then heating from 300-320℃ to 800-810℃ at a heating rate of 3℃ / min, then heating from 800-810℃ to 1350-1360℃ at a heating rate of 2.0℃ / min, and finally heating from 1350-1360℃ to 1510-1530℃ at a heating rate of 2.0℃ / min and holding at that temperature for 3 hours.

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