High-temperature ceramic bonded wear-resistant refractory brick as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of refractory materials, and discloses a high-temperature ceramic bonded wear-resistant refractory brick and a preparation method and application thereof. The high-temperature ceramic bonded wear-resistant refractory brick comprises the following raw materials in percentage by mass: 55-63% of white corundum particles; 18%-23% of silicon carbide fine powder; 8%-12% of rho-Al2O3; 4%-6% of a composite sintering promoter; 2%-4% of metal silicon powder; 3%-5% of an early strength agent; 1%-3% of stainless steel fiber; and 1%-3% of aluminum nitride. The refractory brick disclosed by the invention has ultrahigh high-temperature strength, extreme wear resistance and excellent thermal shock resistance, and is particularly suitable for industrial kiln key parts, such as a downcomer of a belt type roasting machine and the like, which have extreme requirements on high-temperature mechanical properties and wear resistance.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, specifically relating to a high-temperature ceramic-bonded wear-resistant refractory brick, its preparation method, and its application. Background Technology

[0002] In industrial production, core components of industrial kilns, such as the downcomer of belt calciners and key passages in high-temperature calcining kilns, operate under extremely harsh conditions for extended periods. These components not only endure the intense erosion and wear from high-speed, dust-laden flue gas but also face frequent and drastic temperature fluctuations during production, placing extremely high demands on the high-temperature mechanical properties, wear resistance, and thermal shock resistance of refractory materials. Traditional, widely used cement-bonded refractory castables rely primarily on the formation of hydration products for their bonding strength. While they exhibit good performance in medium- and low-temperature environments, under prolonged high-temperature operation or repeated temperature cycling, these hydration products are prone to dehydration and decomposition. This leads to a sharp decline in the material's bonding strength, a loose internal structure, and consequently, accelerated wear and spalling, making it difficult to meet the long-term stable operation requirements of critical components in industrial kilns.

[0003] To address the shortcomings of traditional materials, ceramic-bonded refractories have attracted attention due to their unique advantages. These materials, through a high-temperature sintering process, can form a ceramic phase bonded by covalent or ionic bonds between particles. This bonded phase remains stable within a temperature range close to its melting point, endowing the material with excellent high-temperature strength, creep resistance, and volume stability. However, achieving complete ceramic bonding in existing technologies often requires extremely high sintering temperatures exceeding 1600℃ or relies on special sintering aids. This not only significantly increases energy consumption and process complexity but also frequently results in excessive compression of the material's internal structure during the densification process, leading to a substantial sacrifice in thermal shock resistance. Therefore, developing a refractory material that can form a strong ceramic bond at a relatively moderate temperature while simultaneously possessing high wear resistance, high strength, and excellent thermal shock resistance has become a core direction for solving the long-term operational challenges of critical components in industrial kilns such as belt kiln downcomers. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology by providing a high-temperature ceramic-bonded wear-resistant refractory brick, its preparation method and application. The refractory brick has extremely high high-temperature strength, extreme wear resistance and excellent thermal shock resistance, and is particularly suitable for key parts of industrial kilns such as the downcomer of belt kilns where there are extreme requirements for high-temperature mechanical properties and wear resistance.

[0005] To address the technical problem presented in this invention, this invention provides a high-temperature ceramic-bonded wear-resistant refractory brick, comprising the following raw materials in weight percentages: 55-63% white corundum particles; 18-23% silicon carbide fine powder; and p-Al2O3. 8~12%; composite sintering accelerator 4~6%; metallic silicon powder 2~4%; early strength agent 3~5%; stainless steel fiber 1~3%; aluminum nitride 1~3%.

[0006] In the above scheme, the white corundum particles are graded in a weight ratio of 35:(25~40):(15~35) for three particle sizes of 5~3mm, 3~1mm and 1~0mm.

[0007] In the above scheme, the white fused alumina particles have an Al2O3 content of 99.14~99.81wt%, a SiO2 content of <0.10wt%, and a Fe2O3 content of <0.10wt%.

[0008] In the above scheme, the particle size of the silicon carbide fine powder is ≤0.044mm and the SiC content is ≥98wt%.

[0009] In the above scheme, the ρ-Al2O3 has a ρ-Al2O3 content ≥ 80 wt%, a SiO2 content < 0.05 wt%, a Fe2O3 content < 0.03 wt%, a Na2O content < 0.4 wt%, and a loss on ignition ≤ 10%.

[0010] In the above scheme, the silicon content of the metallic silicon powder is ≥99.9 wt%, and the particle size distribution is 1~10μm.

[0011] In the above scheme, the stainless steel fiber has a length of 25~30mm and a diameter of 1~2.5mm.

[0012] In the above scheme, the stainless steel fiber is heat-resistant stainless steel, which can withstand high temperatures above 1000℃ for a long time, and is preferably one or more of AISI330, AISI430 and AISI446 stainless steel.

[0013] In the above scheme, the aluminum nitride has a particle size of 20~80μm and a purity of >99%.

[0014] In the above scheme, the composite sintering accelerator is composed of kaolin, silica micro powder, sodium oxide and yttrium cerium oxide composite micro powder.

[0015] Furthermore, the mass ratio of the composite micro powder of kaolin, silica powder, sodium oxide and yttrium cerium oxide is 5: (1.8~2.1): (0.8~1.1): (0.1~0.3).

[0016] Furthermore, the yttrium cerium oxide composite micro powder is composed of CeO2 and Y2O3 in a mass ratio of 2:(4~8).

[0017] Furthermore, the kaolin has a particle size ≤ 2 μm; the silica micro powder has a particle size of 0.1~1 μm and a SiO2 content > 99 wt%; the sodium oxide has a particle size ≤ 0.074 mm and a purity ≥ 85%; the yttrium cerium oxide composite micro powder has a particle size ≤ 0.5 μm, wherein the Y2O3 purity ≥ 99.9% and the CeO2 purity ≥ 99.9%.

[0018] In the above scheme, the early strength agent is composed of modified alumina fiber, magnesium aluminate sol binder and triethanolamine.

[0019] Furthermore, the mass ratio of the modified alumina fiber, magnesium aluminate sol binder, and triethanolamine is 5:(3~8):(2~5).

[0020] Furthermore, the modified alumina fiber is prepared by dispersing alumina fiber in an ethanol aqueous solution of silane coupling agent, adding an initiator, then adding a mixed solution of styrene and methyl methacrylate dropwise and heating to react. After the reaction, the fiber is removed and heated to cure, thus obtaining the modified alumina fiber.

[0021] Furthermore, the alumina fiber has a length of 15~25mm and a diameter of 10~12μm.

[0022] Furthermore, the silane coupling agent is one of γ-methacryloxypropyltrimethoxysilane (KH-570), γ-aminopropyltriethoxysilane (KH-550), and vinyltrimethoxysilane.

[0023] Furthermore, the ethanol aqueous solution of the silane coupling agent is composed of the silane coupling agent and the ethanol aqueous solution at a mass ratio of 2:(10~15); the volume fraction of ethanol in the ethanol aqueous solution is 90~95%.

[0024] Furthermore, the mass ratio of the alumina fiber to the silane coupling agent is 10:(1~4).

[0025] Furthermore, the initiator is one of benzoyl peroxide and methyl ethyl ketone peroxide, and the amount added is 1 to 3% of the mass of alumina fiber.

[0026] Furthermore, the mass ratio of styrene to methyl methacrylate in the mixed solution of styrene and methyl methacrylate is 3:(5~8).

[0027] Furthermore, the amount of the mixed solution of styrene and methyl methacrylate added is 3-7% of the mass of the alumina fiber.

[0028] Furthermore, the heating temperature of the heating reaction is 70~90℃, the mixed solution of styrene and methyl methacrylate is added dropwise within 5~30 minutes, and the total reaction time (including the dropwise addition time) is 2~4 hours.

[0029] Furthermore, the heating temperature for heat curing is 100~120℃, and the curing time is 8~12h.

[0030] Furthermore, the magnesium aluminate sol binder has an MgO content of ≥45% and an Al2O3 content of ≥1.5%.

[0031] Furthermore, the purity of the triethanolamine is ≥96%.

[0032] This invention also provides a method for preparing high-temperature ceramic-bonded wear-resistant refractory bricks, comprising the following steps: 1) Dry mix all raw materials except early strength agent and stainless steel fiber evenly, then add early strength agent and wet mix, and finally add stainless steel fiber and mix evenly to obtain a mixture. 2) After the mixture is trapped in a closed environment, water is added to the surface and then heated and pressed into a refractory brick blank. After drying, it is sintered to obtain a high-temperature ceramic-bonded wear-resistant refractory brick.

[0033] In the above scheme, the material trapping time is 12~24h.

[0034] In the above scheme, the amount of water added is 0.5% to 1.5% of the mass of the mixture.

[0035] In the above scheme, the heating temperature for heating and pressing is 180~200℃, and the pressing pressure is 100~150MPa.

[0036] In the above scheme, the drying temperature is 100~120℃ and the drying time is 24~48h.

[0037] In the above scheme, the sintering temperature is 1450~1550℃, the holding time is 6~12h, and the furnace is cooled after sintering.

[0038] In the above scheme, the sintering process first introduces an argon-nitrogen mixed gas, and then raises the temperature to 950-1050℃ at a rate of 200-250℃ / h, followed by raising the temperature to 1300-1400℃ at a rate of 40-50℃ / h and holding it for 0.4-0.6h. Then, the process is changed to introducing a nitrogen-hydrogen mixed atmosphere, and the temperature is raised to the sintering temperature at a rate of 30-40℃ / h and held.

[0039] Furthermore, the volume percentage of argon in the argon-nitrogen mixed gas is 60%~68%, and the volume percentage of nitrogen is 32%~40%.

[0040] Furthermore, the nitrogen-hydrogen mixture contains 90-95% nitrogen by volume and 5-10% hydrogen by volume.

[0041] Furthermore, the nitrogen-hydrogen mixed gas has a water content of ≤0.5% and an oxygen content of ≤0.5%.

[0042] In the above scheme, the bulk density of the high-temperature ceramic-bonded wear-resistant refractory brick is 3.5~3.7 g / cm³. 3 The compressive strength at room temperature is 120~148MPa, and the compressive strength after holding at 1400℃ for 3 hours is 184~215MPa. The abrasion resistance is 3~4cm. 3 The water-cooled thermal shock at 1100℃ has been repeated more than 30 times.

[0043] The present invention also provides an application of high-temperature ceramic-bonded wear-resistant refractory bricks, which can be used as lining material for downcomers in industrial kilns such as belt kilns.

[0044] The main technical concepts of this invention include: This invention relates to a high-temperature ceramic-bonded wear-resistant refractory brick using wear-resistant white corundum and silicon carbide as aggregates. Early body strength is provided through the hydration bonding effect of ρ-Al₂O₃. Metallic silicon powder is sintered under a nitrogen atmosphere to form silicon nitride ceramics. A composite sintering agent is introduced, in which sodium oxide acts as a flux and reacts with submicron silica powder at a lower temperature to generate liquid sodium silicate, promoting subsequent rearrangement of silicon nitride particles and liquid phase filling, thus improving the degree of ceramic sintering and achieving a strong ceramic bond at a relatively moderate temperature. Kaolin provides plasticity and bonding properties while generating a mullite phase during high-temperature sintering. Yttrium cerium oxide composite micropowder forms a network structure at grain boundaries, hindering crack propagation and simultaneously generating phase transformation toughening. Through the interaction between these composite sintering agents, a more uniform and dense microstructure is formed, significantly improving the strength and toughness of the ceramic. Early strength agents are introduced, with modified alumina fibers forming molecular bridges between the alumina fiber surface and organic polymers via silane coupling agents. This cross-linking polymerization reaction creates a three-dimensional network structure on the alumina fiber surface, achieving early strength. Magnesium aluminate sol binder provides early bonding strength, and the formation of magnesium aluminum spinel phase during high-temperature sintering enhances high-temperature strength. Triethanolamine, acting as a complexing catalyst, does not directly constitute the final product but significantly accelerates the early strength formation process. It also activates the magnesium aluminate sol, improving the interfacial bonding between the fiber and the matrix, allowing the toughening and strengthening effects of the alumina fibers to be fully realized. Stainless steel fibers are introduced; their bridging and pull-out mechanisms dissipate fracture energy, improving the material's thermal shock resistance and extending its service life. Aluminum nitride is introduced; after the mixture is cured, water is added, and the mixture is heated to above 180°C. Under mechanical pressure, the aluminum nitride powder and water undergo a hydration-dehydration reaction to generate boehmite in situ, enhancing the densification of both aluminum nitride and silicon nitride ceramics, thereby increasing the material's strength.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention's refractory bricks possess ultra-high high-temperature strength, exceptional wear resistance, and outstanding thermal shock resistance through the synergistic effect of their components. They are particularly suitable for critical components of industrial kilns, such as the downcomer of belt-type calciners, where extreme requirements for high-temperature mechanical properties and wear resistance are present. These refractory bricks do not require extremely high sintering temperatures exceeding 1600℃; complete ceramic bonding between material particles can be achieved under relatively mild temperature conditions. This significantly reduces heat consumption during sintering, lowers carbon emissions and energy costs in the production stage, aligns with the current trend of low-carbon and green development in the industrial sector, and offers significant economic and environmental benefits. Detailed Implementation

[0046] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0047] In the following examples, the raw materials used include: white corundum particles with particle sizes of 5-3 mm, 3-1 mm, and 1-0 mm, Al2O3 content of 99.14-99.81 wt%, SiO2 content of <0.10 wt%, and Fe2O3 content of <0.10 wt%; silicon carbide fine powder with a particle size ≤0.044 mm and SiC content ≥98 wt%; p-Al2O3 with a p-Al2O3 content ≥80 wt%, SiO2 content of <0.05 wt%, Fe2O3 content of <0.03 wt%, Na2O of <0.4 wt%, and loss on ignition ≤10%; kaolin with a particle size ≤2 μm; silica micro powder with a particle size of 0.1-1 μm and SiO2 content >99 wt%; sodium oxide with a particle size ≤0.074 mm and purity ≥85%; Y2O3 with purity ≥99.9%; CeO2 with purity ≥99.9%; and metallic silicon powder with Si content ≥99.9%. wt%, particle size 1~10μm; alumina fiber, length 15~25mm, diameter 10~12μm; magnesium aluminate sol binder, model W3297BX, MgO content ≥45%, Al2O3 content ≥1.5%; triethanolamine, purity 96%~98%; AISI330 stainless steel fiber, length 25~30mm, diameter 1~2.5mm; aluminum nitride, particle size 20~80μm, purity >99%.

[0048] Example 1 The high-temperature ceramic-bonded wear-resistant refractory brick of this embodiment comprises the following raw materials in the following mass percentages: 60% white fused alumina particles, of which 21% are 5-3mm white fused alumina particles, 18% are 3-1mm white fused alumina particles, and 21% are 1-0mm white fused alumina particles, with a mass ratio of 35:30:35; 18% silicon carbide fine powder; and p-Al2O3. 11%; composite sintering accelerator 4%; metallic silicon powder 2%; early strength agent 3%; stainless steel fiber 1%; aluminum nitride 1%.

[0049] The composite sintering accelerator is composed of kaolin, silica micro powder, sodium oxide and yttrium cerium oxide composite micro powder in a mass ratio of 5:1.8:0.9:0.1; wherein, the yttrium cerium oxide composite micro powder is composed of CeO2 and Y2O3 in a mass ratio of 2:4, and the particle size is ≤0.5μm.

[0050] The early strength agent is composed of modified alumina fiber, magnesium aluminate sol binder, and triethanolamine in a mass ratio of 5:3:2. The modified alumina fiber is prepared by dispersing alumina fiber in a solution composed of γ-methacryloyloxypropyltrimethoxysilane (KH-570) and 95% ethanol aqueous solution in a mass ratio of 2:10, with the mass ratio of alumina fiber to silane coupling agent being 10:4. 1% benzoyl peroxide by mass of alumina fiber is added, followed by dropwise addition of a solution composed of styrene and methyl methacrylate in a mass ratio of 3:5 by mass of alumina fiber. The mixture is heated to 80°C and the reaction is completed in 20 minutes. The total reaction time is 2 hours. After the reaction, the fiber is removed and cured at 110°C for 8 hours to obtain the modified alumina fiber.

[0051] The preparation method of high-temperature ceramic-bonded wear-resistant refractory bricks in this embodiment includes the following steps: 1) Dry mix all raw materials except early strength agent and stainless steel fiber for 12 minutes, then add early strength agent and wet mix for 18 minutes, and finally add stainless steel fiber and continue mixing for 5 minutes to obtain the mixture. 2) After the mixture is conditioned in a closed environment for 18 hours, 0.5% water by weight of the mixture is added to the surface. The mixture is then heated to 180℃ and pressed into refractory brick blanks under a pressure of 120MPa. After drying at 110℃ for 36 hours, the blanks are sintered. During the sintering process, an argon-nitrogen mixed gas (65% argon + 35% nitrogen) is first introduced, and the temperature is raised to 1000℃ at a rate of 250℃ / h. Then, the temperature is raised to 1350℃ at a rate of 40℃ / h and held for 0.5 hours. Then, a nitrogen-hydrogen mixed atmosphere (95% nitrogen + 5% hydrogen, water content ≤0.5%, oxygen content ≤0.5%) is introduced, and the temperature is raised to 1450℃ at a rate of 30℃ / h and held for 6 hours. After sintering, the blanks are cooled with the furnace to obtain high-temperature ceramic-bonded wear-resistant refractory bricks.

[0052] The bulk density (after firing at 1500℃) of the obtained high-temperature ceramic-bonded wear-resistant refractory brick was tested to be 3.55 g / cm³. 3 The compressive strength at room temperature is 131.65 MPa, and the compressive strength after holding at 1400℃ for 3 hours is 195 MPa. The abrasion resistance is 3.6 cm. 3 The thermal shock resistance (1100℃, water cooling) is >30 cycles. This high-temperature ceramic-bonded wear-resistant refractory brick can be applied to the downcomer of a belt calender, specifically as the inner lining material of the downcomer.

[0053] Example 2 The high-temperature ceramic-bonded wear-resistant refractory brick of this embodiment comprises the following raw materials in weight percentage: 55% white fused alumina particles, of which 19.25% are 5-3mm white fused alumina particles, 16.5% are 3-1mm white fused alumina particles, and 19.25% are 1-0mm white fused alumina particles, with a weight ratio of 35:30:35; 19% silicon carbide fine powder; and p-Al2O3. 8%; composite sintering accelerator 6%; metallic silicon powder 4%; early strength agent 5%; stainless steel fiber 1%; aluminum nitride 2%.

[0054] The composite sintering accelerator is composed of kaolin, silica micro powder, sodium oxide and yttrium cerium oxide composite micro powder in a mass ratio of 5:1.9:1.0:0.1; wherein, the yttrium cerium oxide composite micro powder is composed of CeO2 and Y2O3 in a mass ratio of 2:6, and the particle size is ≤0.5μm.

[0055] The early strength agent is composed of modified alumina fiber, magnesium aluminate sol binder, and triethanolamine in a mass ratio of 5:7:3. The modified alumina fiber is prepared by dispersing alumina fiber in a solution of γ-aminopropyltriethoxysilane (KH-550) and 95% ethanol aqueous solution in a mass ratio of 2:11, with the mass ratio of alumina fiber to silane coupling agent being 10:2. 1% of the mass of alumina fiber is added with methyl ethyl ketone peroxide, followed by dropwise addition of 5% of the mass of alumina fiber in a solution of styrene and methyl methacrylate in a mass ratio of 3:6. The mixture is heated to 80°C and the reaction is completed in 8 minutes. The total reaction time is 4 hours. After the reaction, the fiber is removed and cured at 110°C for 9 hours to obtain the modified alumina fiber.

[0056] The preparation method of high-temperature ceramic-bonded wear-resistant refractory bricks in this embodiment includes the following steps: 1) Dry mix all raw materials except early strength agent and stainless steel fiber for 12 minutes, then add early strength agent and wet mix for 18 minutes, and finally add stainless steel fiber and continue mixing for 5 minutes to obtain the mixture. 2) After the mixture is conditioned in a closed environment for 18 hours, 1.0% water by weight of the mixture is added to the surface, and then heated to 200℃ and pressed into refractory brick blanks under 120MPa pressure. After drying at 110℃ for 36 hours, sintering is carried out. During the sintering process, an argon-nitrogen mixed gas (68% argon + 32% nitrogen) is first introduced, and the temperature is raised to 1000℃ at a rate of 200℃ / h, then raised to 1350℃ at a rate of 50℃ / h and held for 0.5 hours. Then, a nitrogen-hydrogen mixed atmosphere (90% nitrogen + 10% hydrogen, water content ≤0.5%, oxygen content ≤0.5%) is introduced, and the temperature is raised to 1550℃ at a rate of 30℃ / h and held for 10 hours. After sintering, the mixture is cooled with the furnace to obtain high-temperature ceramic-bonded wear-resistant refractory bricks.

[0057] The bulk density (after firing at 1500℃) of the obtained high-temperature ceramic-bonded wear-resistant refractory brick was tested to be 3.61 g / cm³. 3 The compressive strength at room temperature is 145.35 MPa, and the compressive strength after holding at 1400℃ for 3 hours is 204 MPa. The abrasion resistance is 3.2 cm. 3 The thermal shock resistance (1100℃, water cooling) is >30 cycles. This high-temperature ceramic-bonded wear-resistant refractory brick can be applied to the downcomer of a belt calender, specifically as the inner lining material of the downcomer.

[0058] Example 3 The high-temperature ceramic-bonded wear-resistant refractory brick of this embodiment comprises the following raw materials in weight percentage: 61% white fused alumina particles, of which 21.35% are 5-3mm white fused alumina particles, 21.35% are 3-1mm white fused alumina particles, and 18.3% are 1-0mm white fused alumina particles, with a weight ratio of 35:35:30; 18% silicon carbide fine powder; and p-Al2O3. 8%; composite sintering accelerator 4%; metallic silicon powder 2%; early strength agent 3%; stainless steel fiber 1%; aluminum nitride 3%.

[0059] The composite sintering accelerator is composed of kaolin, silica micro powder, sodium oxide and yttrium cerium oxide composite micro powder in a mass ratio of 5:2.0:1.1:0.3; wherein, the yttrium cerium oxide composite micro powder is composed of CeO2 and Y2O3 in a mass ratio of 2:7, and the particle size is ≤0.5μm.

[0060] The early strength agent is composed of modified alumina fiber, magnesium aluminate sol binder, and triethanolamine in a mass ratio of 5:8:2. The modified alumina fiber is prepared by dispersing alumina fiber in a solution of vinyltrimethoxysilane and 95% ethanol aqueous solution in a mass ratio of 2:15, with the mass ratio of alumina fiber to silane coupling agent being 10:4. 3% benzoyl peroxide by mass of alumina fiber is added, followed by dropwise addition of a solution of styrene and methyl methacrylate in a mass ratio of 3:7 by mass of alumina fiber. The mixture is heated to 80°C and the reaction is completed in 15 minutes. The total reaction time is 4 hours. After the reaction, the fiber is removed and cured at 120°C for 12 hours to obtain the modified alumina fiber.

[0061] The preparation method of high-temperature ceramic-bonded wear-resistant refractory bricks in this embodiment includes the following steps: 1) Dry mix all raw materials except early strength agent and stainless steel fiber for 12 minutes, then add early strength agent and wet mix for 18 minutes, and finally add stainless steel fiber and continue mixing for 5 minutes to obtain the mixture. 2) After the mixture is conditioned in a closed environment for 18 hours, 1.5% water by weight of the mixture is added to the surface, and then heated to 200℃ and pressed into refractory brick blanks under 100MPa pressure. After drying at 110℃ for 36 hours, sintering is carried out. During the sintering process, an argon-nitrogen mixed gas (60% argon + 40% nitrogen) is first introduced, and the temperature is raised to 1000℃ at a rate of 250℃ / h, then raised to 1350℃ at a rate of 50℃ / h and held for 0.5 hours. Then, a nitrogen-hydrogen mixed atmosphere (95% nitrogen + 5% hydrogen, water content ≤0.5%, oxygen content ≤0.5%) is introduced, and the temperature is raised to 1500℃ at a rate of 40℃ / h and held for 8 hours. After sintering, the mixture is cooled with the furnace to obtain high-temperature ceramic-bonded wear-resistant refractory bricks.

[0062] The bulk density (after firing at 1500℃) of the obtained high-temperature ceramic-bonded wear-resistant refractory brick was tested to be 3.59 g / cm³. 3 The compressive strength at room temperature is 130.14 MPa, and the compressive strength after holding at 1400℃ for 3 hours is 183 MPa. The abrasion resistance is 3.7 cm. 3 The thermal shock resistance (1100℃, water cooling) is >30 cycles. This high-temperature ceramic-bonded wear-resistant refractory brick can be applied to the downcomer of a belt calender, specifically as the inner lining material of the downcomer.

[0063] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the composite sintering accelerator in the raw materials of the refractory bricks is composed of kaolin and yttrium cerium oxide composite micro powder mixed in a mass ratio of 5:0.1.

[0064] The bulk density of the obtained refractory bricks (after firing at 1500℃) was measured to be 3.51 g / cm³. 3 The compressive strength at room temperature is 111.24 MPa, and the compressive strength after holding at 1400℃ for 3 hours is 173.45 MPa. The abrasion resistance is 3.9 cm. 3 Cracks appeared after 24 cycles of thermal shock resistance test (1100℃, water cooling). Compared with Example 1, the bulk density, room temperature compressive strength, high temperature firing compressive strength, and wear resistance of this refractory brick were significantly reduced.

[0065] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that in the preparation of refractory bricks, after the material is trapped, no water is added to the surface, and it is directly pressed into refractory brick blanks, and then subsequent drying and sintering are carried out.

[0066] The bulk density of the obtained refractory bricks (after firing at 1500℃) was measured to be 3.49 g / cm³. 3 The compressive strength at room temperature is 108.78 MPa, and the compressive strength after holding at 1400℃ for 3 hours is 157.71 MPa. The abrasion resistance is 4.1 cm. 3The refractory brick exhibited cracks after 28 thermal shock tests (1100℃, water cooling). Compared with Example 1, the bulk density, room temperature compressive strength, high temperature compressive strength after firing, and wear resistance of the refractory brick were significantly reduced.

[0067] The above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A high-temperature ceramic-bonded wear-resistant refractory brick, characterized in that, Raw materials include the following percentages by weight: 55-63% white fused alumina particles, 18-23% silicon carbide fine powder, and p-Al2O3. 8~12%, composite sintering accelerator 4~6%, metallic silicon powder 2~4%, early strength agent 3~5%, stainless steel fiber 1~3%, aluminum nitride 1~3%; The composite sintering accelerator is composed of kaolin, silica micro powder, sodium oxide and yttrium cerium oxide composite micro powder; the early strength agent is composed of modified alumina fiber, magnesium aluminate sol binder and triethanolamine; The modified alumina fiber is prepared by dispersing alumina fiber in an ethanol aqueous solution of silane coupling agent, adding an initiator, then adding a mixed solution of styrene and methyl methacrylate dropwise and heating to react. After the reaction, the fiber is removed and heated to cure, thus obtaining the modified alumina fiber.

2. The high-temperature ceramic-bonded wear-resistant refractory brick according to claim 1, characterized in that, The mass ratio of the composite micro-powder of kaolin, silica, sodium oxide, and yttrium cerium oxide is 5:(1.8~2.1):(0.8~1.1):(0.1~0.3); the composite micro-powder of yttrium cerium oxide is composed of CeO2 and Y2O3 in a mass ratio of 2:(4~8); the particle size of the kaolin is ≤2μm; the particle size of the silica is 0.1~1μm, and the SiO2 content is >99%; the particle size of the sodium oxide is ≤0.074mm, and the purity is ≥85%; the particle size of the composite micro-powder of yttrium cerium oxide is ≤0.5μm, the purity of Y2O3 is ≥99.9%, and the purity of CeO2 is ≥99.9%.

3. The high-temperature ceramic-bonded wear-resistant refractory brick according to claim 1, characterized in that, The mass ratio of alumina fiber to silane coupling agent is 10:(1~4); the mixed solution of styrene and methyl methacrylate is composed of styrene and methyl methacrylate in a mass ratio of 3:(5~8), and the amount added is 3~7% of the mass of alumina fiber; the heating temperature of the heating reaction is 70~90℃, and the reaction time is 2~4h; the mass ratio of modified alumina fiber, magnesium aluminate sol binder and triethanolamine is 5:(3~8):(2~5).

4. The high-temperature ceramic-bonded wear-resistant refractory brick according to claim 1, characterized in that, The silane coupling agent is one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and vinyltrimethoxysilane; the initiator is benzoyl peroxide or methyl ethyl ketone peroxide, and the amount added is 1-3% of the mass of alumina fiber; the ethanol aqueous solution of the silane coupling agent is composed of the silane coupling agent and the ethanol aqueous solution at a mass ratio of 2:(10-15); the volume fraction of ethanol in the ethanol aqueous solution is 90-95%; the heating curing temperature is 100-120℃, and the time is 8-12h.

5. The high-temperature ceramic-bonded wear-resistant refractory brick according to claim 1, characterized in that, The white fused alumina particles are graded in a weight ratio of 35:(25~40):(15~35) for three particle sizes: 5~3mm, 3~1mm, and 1~0mm; the white fused alumina particles have an Al2O3 content of 99.14~99.81wt%, SiO2 content <0.10wt%, and Fe2O3 content <0.10wt%; the silicon carbide fine powder has a particle size ≤0.044mm and a SiC content ≥98wt%; the p-Al2O3 has a p-Al2O3 content ≥80wt%, SiO2 content <0.05wt%, Fe2O3 content <0.03wt%, Na2O <0.4wt%, and a loss on ignition ≤10%.

6. The high-temperature ceramic-bonded wear-resistant refractory brick according to claim 1, characterized in that, The silicon powder has a Si content ≥99.9 wt% and a particle size distribution of 1~10 μm; the stainless steel fiber is heat-resistant stainless steel with a length of 25~30 mm and a diameter of 1~2.5 mm; the aluminum nitride has a particle size of 20~80 μm and a purity >99%; the alumina fiber has a length of 15~25 mm and a diameter of 10~12 μm; the magnesium aluminate sol binder has an MgO content ≥45% and an Al2O3 content ≥1.5%; and the triethanolamine has a purity ≥96%.

7. A method for preparing a high-temperature ceramic-bonded wear-resistant refractory brick as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) Dry mix all raw materials except early strength agent and stainless steel fiber evenly, then add early strength agent and wet mix, and finally add stainless steel fiber and mix evenly to obtain a mixture. 2) After the mixture is trapped in a closed environment, water is added to the surface and then heated and pressed into a refractory brick blank. After drying, it is sintered to obtain a high-temperature ceramic-bonded wear-resistant refractory brick.

8. The method for preparing high-temperature ceramic-bonded wear-resistant refractory bricks according to claim 7, characterized in that, The material is allowed to linger for 12 to 24 hours; the amount of water added is 0.5% to 1.5% of the mass of the mixture; the heating temperature for heating and pressing is 180 to 200°C, and the pressing pressure is 100 to 150 MPa; the sintering temperature is 1450 to 1550°C, the holding time is 6 to 12 hours, and the material is cooled with the furnace after sintering.

9. The method for preparing high-temperature ceramic-bonded wear-resistant refractory bricks according to claim 7, characterized in that, The sintering process begins by introducing an argon-nitrogen mixed gas and heating the temperature to 950-1050°C at a rate of 200-250°C / h. Then, the temperature is increased to 1300-1400°C at a rate of 40-50°C / h and held for 0.4-0.6h. After that, a nitrogen-hydrogen mixed atmosphere is introduced and the temperature is further increased to the sintering temperature at a rate of 30-40°C / h and held.

10. The application of a high-temperature ceramic-bonded wear-resistant refractory brick as described in any one of claims 1 to 6 in the downcomer of an industrial kiln.

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