Al2O3-SiO2 refractory brick for hazardous waste incinerator and preparation method of Al2O3-SiO2 refractory brick

Abstract

The invention relates to the technical field of preparation of refractory materials, in particular to an Al2O3-SiO2 refractory brick for a hazardous waste incinerator and a preparation method of the Al2O3-SiO2 refractory brick. The refractory brick is prepared from the following raw materials: sintered mullite, high-alumina bauxite, silicon carbide, a fiber material, a refractory additive, a binding agent and a fluxing agent, the preparation method of the refractory brick comprises the following steps: 1, mixing sintered mullite and high bauxite, adding silicon carbide, a refractory additive and a fluxing agent, uniformly stirring, adding a binding agent and a fiber material, adding deionized water, and uniformly dispersing to obtain slurry; step 2, adding the slurry into a mold, and performing compression molding to obtain a green brick; 3, after the green bricks are dried, sintering is carried out through a temperature programming sintering technology, natural cooling along with a furnace is carried out, and the refractory bricks are obtained, the prepared refractory bricks are excellent in comprehensive performance, high in mechanical strength, good in fire resistance and excellent in thermal shock resistance and can effectively cope with temperature fluctuation, and it is guaranteed that an incinerator operates stably and reliably.

Description

Technical Field

[0001] The present application relates to the technical field of refractory material preparation, and more specifically, to an Al2O3-SiO2 refractory brick for a hazardous waste incinerator and a preparation method thereof. Background Art

[0002] With the acceleration of industrialization, the amount of hazardous waste generated continues to rise, and its treatment and disposal has become a key challenge in the field of environmental protection. Hazardous waste incineration, with its efficient reduction and harmless treatment characteristics, occupies a very important position in the field of hazardous waste disposal. As the core equipment for hazardous waste incineration, the performance and lifespan of the incinerator are directly related to the effectiveness and cost of hazardous waste treatment. Refractory bricks, as the key material for the lining of incinerators, have many important tasks, such as withstanding high temperatures, resisting corrosion, and protecting the furnace structure. Therefore, the development of high-performance refractory bricks for hazardous waste incinerators is of great significance for improving hazardous waste incineration efficiency, reducing operating costs, and ensuring environmental safety.

[0003] The refractory bricks commonly used in hazardous waste incinerators mainly include high-alumina bricks, corundum bricks, silicon carbide bricks, etc. Although the commonly used refractory bricks have their own advantages, they also have many shortcomings. High-alumina bricks have poor corrosion resistance and are easily corroded by acidic gases and slag, which limits their service life; corundum bricks are expensive and have corrosion risks in the incineration environment of hazardous waste containing alkali metals; silicon carbide bricks have poor oxidation resistance and are easily oxidized in an oxidizing atmosphere, which affects their service life. In addition, during the hazardous waste incineration process, the temperature in the incinerator will fluctuate frequently due to factors such as the unevenness of the feed and the stability of combustion. This rapid change in temperature will generate thermal stress inside the refractory bricks. When the thermal stress exceeds the bearing capacity of the refractory bricks, the refractory bricks will crack, peel off, etc., which seriously affect their service life. Based on the above statements, the present application provides an Al2O3-SiO2 refractory brick for hazardous waste incinerators with high refractoriness, excellent corrosion resistance, and good thermal shock resistance, and a preparation method thereof to meet the growing demand for hazardous waste incineration treatment. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the present application provides an Al2O3-SiO2 refractory brick for a hazardous waste incinerator and a preparation method thereof.

[0005] In the first aspect, the present application provides an Al2O3-SiO2 refractory brick for a hazardous waste incinerator, which adopts the following technical solution: An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65-80 parts of sintered mullite, 12-15 parts of high-alumina bauxite, 3-5 parts of silicon carbide, 1-3 parts of fiber material, 10-15 parts of refractory additive, 4-6 parts of binder, and 2-5 parts of flux.

[0006] Preferably, the Al2O3 content in the sintered mullite is 40-50%, the SiO2 content is 45-52%, and the iron content is ≤0.5%.

[0007] Preferably, the high-alumina bauxite includes three particle size specifications: 2-5 mm, 0.5-2 mm and ≤0.088 mm.

[0008] Preferably, the mass ratio of high alumina with a particle size of 2-5 mm, high alumina with a particle size of 0.5-2 mm and particle size ≤0.088 mm in the high alumina is 30-42:25-35:30-40.

[0009] Preferably, the fiber material is one or more of polyacrylonitrile fiber, graphene fiber, and carbon fiber.

[0010] Preferably, the refractory additive is composed of magnesiaite, magnesia-alumina spinel and lithium carbonate in a mass ratio of 30-45:40-60:10-18.

[0011] Preferably, the binder consists of aluminate cement, aluminum dihydrogen phosphate, silica sol and deionized water in a mass ratio of 10-15:8-12:3-6:100-200.

[0012] Preferably, the flux is one or more of gehelite, forsterite, and borosilicate glass powder.

[0013] In a second aspect, the present application provides a method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators, comprising the following steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, obtain slurry, and adjust the moisture content of the slurry to 18-25%; Step 2: Add the slurry into the mold and press it into shape to obtain a brick; Step 3: After the bricks are dried, they are sintered using a programmed temperature sintering process and naturally cooled in the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0014] Preferably, the pressing pressure in step 2 is 80-120 MPa, and the pressure is maintained for 8-15 seconds.

[0015] Preferably, the programmed temperature sintering process is: heating from room temperature to 200-300°C at a heating rate of 5-8°C, keeping warm for 1-2 hours, heating to 400-600°C at a heating rate of 3-5°C, keeping warm for 2-4 hours, heating to 800-1000°C at a heating rate of 5-10°C, keeping warm for 3-5 hours, heating to 1200-1350°C at a heating rate of 2-5°C, and keeping warm for 6-8 hours.

[0016] In summary, this application has the following beneficial effects: This application uses high-alumina bauxite of different particle sizes for compounding, where different particle sizes can form a tightly packed structure to improve density and mechanical strength. Coarse particles mainly serve as the structural skeleton of refractory bricks, providing initial strength and deformation resistance, and preventing cracking caused by stress during molding and sintering. The gaps between coarse particles can be filled with medium and fine particles to avoid the loose stacking problem caused by a single particle size, reduce porosity, and make the green body structure more compact, thereby improving compressive strength. In addition, fine powder has a large specific surface area, which can promote solid-phase diffusion between particles during sintering and enhance the bonding force between particles.

[0017] This application uses aluminate cement, aluminum dihydrogen phosphate and silica sol to compound and prepare a binder, wherein the aluminate cement can quickly provide the initial strength of the green body to prevent the brick from cracking during the drying process, the aluminum dihydrogen phosphate forms a weak bond with the hydration product of the aluminate cement, improves the fluidity of the slurry, dehydrates and condenses under medium and low temperature conditions to form a polyphosphate network, and reacts with Al2O3 and SiO2 at high temperature to form an aluminum phosphate glass phase, so that the strength of the brick body continues to increase, and the silica sol dehydrates to form amorphous SiO2, which reacts with Al2O3 in mullite and high-alumina bauxite to form a low-melting-point glass phase, promotes sintering bonding between particles, and enhances the flexural strength of the brick body.

[0018] This application uses a combination of magnesiaite, magnesia-aluminate spinel, and lithium carbonate to create a refractory additive. Magnesiaite and magnesia-aluminate spinel stabilize the high-temperature structure, while lithium carbonate balances the liquid phase with thermal expansion, controlling the apparent porosity of the brick and balancing density with thermal shock resistance. Magnesiaite resists acidic gas corrosion, while magnesia-aluminate spinel resists alkaline slag. Lithium carbonate passivates the erosion interface through a glassy phase, significantly improving corrosion resistance. DETAILED DESCRIPTION

[0019] The present application is further described in detail below with reference to the embodiments.

[0020] The sintered mullite (model: CY050317) used in the examples and comparative examples of the present application was purchased from Lingshou County Chengyang Mining Co., Ltd.; high-alumina bauxite was purchased from Lingshou County Erping Mineral Products Processing Plant; magnesia (particle size: 200 mesh) was purchased from Zibo Ruixi Energy Co., Ltd.; magnesia-alumina spinel was purchased from Henan Hengyang Refractory Materials Co., Ltd.; lithium carbonate was purchased from Shanghai Oujin Industrial Co., Ltd.; aluminate cement was purchased from Zhengzhou Xutai Refractory Materials Co., Ltd.; aluminum dihydrogen phosphate was purchased from Jiangsu Leien Environmental Protection Technology Co., Ltd.; and silica sol was purchased from Jinan Feiyue Chemical Co., Ltd.

[0021] Examples 1-3 provide an Al2O3-SiO2 refractory brick for a hazardous waste incinerator and a preparation method thereof.

[0022] Example 1 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 30:25:30. The fiber material is carbon fiber. The refractory additive consists of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 30:40:10. The binder consists of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 10:8:3:100. The flux is borosilicate glass powder.

[0023] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 200°C at a heating rate of 5°C, kept warm for 1 hour, then raised to 400°C at a heating rate of 3°C, kept warm for 2 hours, then raised to 800°C at a heating rate of 5°C, kept warm for 3 hours, then raised to 1200°C at a heating rate of 2°C, kept warm for 6 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0024] Example 2 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 72 parts of sintered mullite, 13 parts of high-alumina bauxite, 4 parts of silicon carbide, 2 parts of organic fiber, 12 parts of a refractory additive, 5 parts of a binder, and 3 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 36:30:35, the fiber material is carbon fiber, the refractory additive is composed of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 38:50:15, the binder is composed of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 12:10:5:150, and the flux is borosilicate glass powder.

[0025] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 150 rpm to obtain a slurry, and adjust the moisture content of the slurry to 22%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 100 MPa and hold the pressure for 12 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 250°C at a heating rate of 7°C, and kept warm for 1.5 hours. The temperature is then raised to 500°C at a heating rate of 4°C, and kept warm for 3 hours. The temperature is then raised to 900°C at a heating rate of 8°C, and kept warm for 4 hours. The temperature is then raised to 1300°C at a heating rate of 4°C, and kept warm for 7 hours. The bricks are then naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0026] Example 3 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 80 parts of sintered mullite, 15 parts of high-alumina bauxite, 5 parts of silicon carbide, 3 parts of organic fiber, 15 parts of a refractory additive, 6 parts of a binder, and 5 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 42:35:40, the fiber material is carbon fiber, the refractory additive is composed of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 45:60:18, the binder is composed of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 15:12:6:200, and the flux is borosilicate glass powder.

[0027] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 200 rpm to obtain a slurry, and adjust the moisture content of the slurry to 25%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 120 MPa and hold the pressure for 15 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 300°C at a heating rate of 8°C, kept warm for 2 hours, then raised to 600°C at a heating rate of 5°C, kept warm for 4 hours, then raised to 1000°C at a heating rate of 10°C, kept warm for 5 hours, then raised to 1350°C at a heating rate of 5°C, kept warm for 8 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0028] Comparative Example 1 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The high-alumina bauxite has a particle size of 200 mesh, the fiber material is carbon fiber, the refractory additive consists of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 30:40:10, the binder consists of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 10:8:3:100, and the flux is borosilicate glass powder.

[0029] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 200°C at a heating rate of 5°C, kept warm for 1 hour, then raised to 400°C at a heating rate of 3°C, kept warm for 2 hours, then raised to 800°C at a heating rate of 5°C, kept warm for 3 hours, then raised to 1200°C at a heating rate of 2°C, kept warm for 6 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0030] Comparative Example 2 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 30:25:30, the fiber material is carbon fiber, the refractory additive is composed of magnesia borax and magnesia-alumina spinel in a mass ratio of 30:40, the binder is composed of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 10:8:3:100, and the flux is borosilicate glass powder.

[0031] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 200°C at a heating rate of 5°C, kept warm for 1 hour, then raised to 400°C at a heating rate of 3°C, kept warm for 2 hours, then raised to 800°C at a heating rate of 5°C, kept warm for 3 hours, then raised to 1200°C at a heating rate of 2°C, kept warm for 6 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0032] Comparative Example 3 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 30:25:30, the fiber material is carbon fiber, the refractory additive consists of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 30:40:10, the binder consists of aluminate cement, silica sol, and deionized water in a mass ratio of 10:3:100, and the flux is borosilicate glass powder.

[0033] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 200°C at a heating rate of 5°C, kept warm for 1 hour, then raised to 400°C at a heating rate of 3°C, kept warm for 2 hours, then raised to 800°C at a heating rate of 5°C, kept warm for 3 hours, then raised to 1200°C at a heating rate of 2°C, kept warm for 6 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0034] Comparative Example 4 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 30:25:30, the fiber material is carbon fiber, the refractory additive consists of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 30:40:10, the binder consists of aluminate cement, aluminum dihydrogen phosphate, and deionized water in a mass ratio of 10:8:100, and the flux is borosilicate glass powder.

[0035] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After the bricks are dried, they are sintered using a programmed temperature rising sintering process. The temperature is raised from room temperature to 200°C at a heating rate of 5°C, kept warm for 1 hour, then raised to 400°C at a heating rate of 3°C, kept warm for 2 hours, then raised to 800°C at a heating rate of 5°C, kept warm for 3 hours, then raised to 1200°C at a heating rate of 2°C, kept warm for 6 hours, and naturally cooled with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0036] Comparative Example 5 An Al2O3-SiO2 refractory brick for a hazardous waste incinerator comprises the following raw materials in parts by weight: 65 parts of sintered mullite, 12 parts of high-alumina bauxite, 3 parts of silicon carbide, 1 part of organic fiber, 10 parts of a refractory additive, 4 parts of a binder, and 2 parts of a flux. The mass ratio of the high-alumina bauxite with a particle size of 2-5 mm, the high-alumina bauxite with a particle size of 0.5-2 mm, and the particle size ≤0.088 mm is 30:25:30, the fiber material is carbon fiber, the refractory additive consists of magnesia borax, magnesia-alumina spinel, and lithium carbonate in a mass ratio of 30:40:10, the binder consists of aluminate cement, aluminum dihydrogen phosphate, silica sol, and deionized water in a mass ratio of 10:8:3:100, and the flux is borosilicate glass powder.

[0037] A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, control the stirring speed to 100 rpm to obtain a slurry, and adjust the moisture content of the slurry to 18%; Step 2: Add the slurry into the mold and press it into shape at a pressure of 80 MPa and hold the pressure for 8 seconds to obtain a green brick. Step 3: After drying the bricks, heat them to 1200°C at a heating rate of 5°C, keep them warm for 12 hours, and cool them naturally with the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

[0038] Performance Testing The performance tests of the Al2O3-SiO2 refractory bricks for hazardous waste incinerators prepared in Examples 1-3 and Comparative Examples 1-5 were conducted as follows: Bulk density: Tested in accordance with the national standard GB / T 2998-2015 "Test method for bulk density and true porosity of shaped thermal insulating refractory products": Compressive strength: Tested in accordance with the national standard GB / T 5072-2008 "Test method for compressive strength of refractory materials at room temperature"; Thermal shock stability: Tested in accordance with the national standard GB / T 30873-2014 "Test method for thermal shock resistance of refractory materials"; The test results are shown in Table 1.

[0039] Table 1 Performance of refractory bricks prepared in Examples 1-3 and Comparative Examples 1-5

[0040] As shown in Table 1, the Al2O3-SiO2 refractory bricks prepared in this application for hazardous waste incinerators exhibit excellent overall performance. They not only possess high mechanical strength and the ability to withstand strong stresses, but also possess excellent fire resistance, enabling long-term stable operation in high-temperature environments. Furthermore, their excellent thermal shock resistance effectively handles temperature fluctuations, ensuring stable and reliable operation of the incinerator.

[0041] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An Al2O3-SiO2 refractory brick for a hazardous waste incinerator, characterized in that: The invention comprises the following raw materials in parts by weight: 65-80 parts of sintered mullite, 12-15 parts of high-alumina bauxite, 3-5 parts of silicon carbide, 1-3 parts of fiber material, 10-15 parts of refractory additive, 4-6 parts of binder and 2-5 parts of flux.

2. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The Al2O3 content of the sintered mullite is 40-50%, the SiO2 content is 45-52%, and the iron content is ≤0.5%.

3. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The high-alumina bauxite includes three particle size specifications: 2-5mm, 0.5-2mm and ≤0.088mm; the mass ratio of the high-alumina bauxite with a particle size of 2-5mm, the high-alumina bauxite with a particle size of 0.5-2mm and the particle size ≤0.088mm in the high-alumina bauxite is 30-42:25-35:30-40.

4. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The fiber material is one or more of polyacrylonitrile fiber, graphene fiber, and carbon fiber.

5. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The refractory additive consists of magnesia borax, magnesia-alumina spinel and lithium carbonate in a mass ratio of 30-45:40-60:10-18.

6. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The binder consists of aluminate cement, aluminum dihydrogen phosphate, silica sol and deionized water in a mass ratio of 10-15:8-12:3-6:100-200.

7. The Al2O3-SiO2 refractory brick for hazardous waste incinerator according to claim 1, characterized in that: The flux is one or more of gehelite, forsterite, and borosilicate glass powder.

8. A method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: Step 1: Mix sintered mullite and high-alumina bauxite, then add silicon carbide, refractory additives, and flux, stir evenly, add binder and fiber material, add deionized water, and after uniform dispersion, obtain slurry, and adjust the moisture content of the slurry to 18-25%; Step 2: Add the slurry into the mold and press it into shape to obtain a brick; Step 3: After the bricks are dried, they are sintered using a programmed temperature sintering process and naturally cooled in the furnace to obtain Al2O3-SiO2 refractory bricks for hazardous waste incinerators.

9. The method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators according to claim 8, characterized in that: The pressing pressure in step 2 is 80-120 MPa, and the pressure is maintained for 8-15 seconds.

10. The method for preparing Al2O3-SiO2 refractory bricks for hazardous waste incinerators according to claim 8, characterized in that: The programmed temperature sintering process is as follows: heating from room temperature to 200-300°C at a heating rate of 5-8°C, keeping warm for 1-2 hours, heating to 400-600°C at a heating rate of 3-5°C, keeping warm for 2-4 hours, heating to 800-1000°C at a heating rate of 5-10°C, keeping warm for 3-5 hours, heating to 1200-1350°C at a heating rate of 2-5°C, and keeping warm for 6-8 hours.

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