Environment-friendly method for preparing mullite fiber based porous ceramic through gel casting

Abstract

The invention belongs to the field of porous ceramic and in particular relates to an environment-friendly method for preparing mullite fiber based porous ceramic through gel casting. The mullite fiberbased porous ceramic is prepared from the following raw materials in percentage by mass: 11 to 32 percent of rho-Al2O3 powder, 13 to 36 percent of kaolin or zircon powder and 33 to 75 percent of mullite fiber. The method comprises the following steps: taking the rho-Al2O3 powder and the kaolin or zircon powder; adding a certain amount of de-ionized water; mechanically stirring and carrying out ultrasonic oscillation to obtain stable and uniform ceramic slurry; then uniformly adding the mullite fibers into the ceramic slurry; continually stirring and oscillating to obtain gel ceramic-fiber slurry; then carrying out injection molding and curing at room temperature; putting a molded biscuit into a constant-temperature drying box and drying; after de-molding, putting into a high-temperature furnace; sintering under an air atmosphere to obtain mullite combined or ZrO2-mullite combined mullite fiber based porous ceramic. The environment-friendly method has a simple and feasible technology and is environmentally friendly; the prepared mullite fiber based porous ceramic has high porosity, low heat conductivity and relatively high strength.

Description

technical field

[0001] The invention belongs to the field of porous ceramics, in particular to an environment-friendly method for preparing mullite fiber-based porous ceramics by gel injection molding. Background technique

[0002] Mullite fiber-based porous ceramics are widely used in high-temperature kilns because of their good thermal stability, low thermal conductivity and thermal expansion coefficient, excellent mechanical strength and excellent chemical stability, and their low cost. Furnace insulation refractories, chemical catalyst carriers, high-temperature flue gas filters and oil-water separation ceramic carriers and other fields. At present, mullite fiber-based porous ceramics are mostly prepared by gel injection molding. This is because the porous ceramics prepared by gel injection molding have the advantages of uniform body, reasonable pore structure, and complex components with near-net shape dimensions. .

[0003] However, the currently used gel casting pro...

Examples

Embodiment 1

[0021] In this example, the raw material adopts ρ-Al 2 o 3 powder, kaolin powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 5 μm, the particle size of the kaolin powder is 25 μm, and the specification size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. Firstly, ρ-Al with a mass percentage of 23.5% 2 o 3 powder, 26.5% kaolin powder for mixing and batching, adding deionized water with 150% of the total mass of raw materials, stirring in a mechanical stirrer and ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then adding a mass percentage of 50% % mullite fiber is evenly added to the ceramic slurry, and the stirring and vibration are continued for 30 minutes to obtain a gel-type ceramic-fiber slurry, which is then injection molded and solidified at room temperature, and the molded green body is placed in a 70°C Dry in a constant temperature drying oven for 96 hours, place in a high-temp...

Embodiment 2

[0024] In this example, the raw material adopts ρ-Al 2 o 3 powder, kaolin powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 3 μm, the particle size of the kaolin powder is 45 μm, and the specification size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. First, ρ-Al with a mass percentage of 15.7% 2 o 3 powder, 17.7% kaolin powder for mixing and batching, adding deionized water with 170% of the total mass of raw materials, stirring in a mechanical stirrer and ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then adding a mass percentage of 66.6 % mullite fiber is evenly added to the ceramic slurry, and the stirring and vibration are continued for 30 minutes to obtain a gel-type ceramic-fiber slurry, which is then injection molded and solidified at room temperature, and the molded green body is placed in a 70°C Dry it in a constant temperature drying oven for 72 hours, place it in a high...

Embodiment 3

[0027] In this example, the raw material adopts ρ-Al 2 o 3 powder, zircon powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 10 μm, the particle size of the zircon powder is 45 μm, and the standard size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. Firstly, ρ-Al with a mass percentage of 11.9% 2 o 3 powder, 13.1% zircon powder for mixing and batching, adding deionized water with 160% of the total mass of raw materials, stirring in a mechanical stirrer and performing ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then the mass percentage Add 75% mullite fiber evenly into the ceramic slurry, continue to stir and vibrate for 30 minutes to obtain a gel-type ceramic-fiber slurry, then injection mold and solidify at room temperature, and mold the green body at 70 ℃ in a constant temperature drying oven for 48 hours, after demoulding, put it in a high-temperature furnace and sinter at a te...

technical field

[0001] The invention belongs to the field of porous ceramics, in particular to an environment-friendly method for preparing mullite fiber-based porous ceramics by gel injection molding. Background technique

[0002] Mullite fiber-based porous ceramics are widely used in high-temperature kilns because of their good thermal stability, low thermal conductivity and thermal expansion coefficient, excellent mechanical strength and excellent chemical stability, and their low cost. Furnace insulation refractories, chemical catalyst carriers, high-temperature flue gas filters and oil-water separation ceramic carriers and other fields. At present, mullite fiber-based porous ceramics are mostly prepared by gel injection molding. This is because the porous ceramics prepared by gel injection molding have the advantages of uniform body, reasonable pore structure, and complex components with near-net shape dimensions. .

[0003] However, the currently used gel casting pro...

Examples

Embodiment 1

[0021] In this example, the raw material adopts ρ-Al 2 o 3 powder, kaolin powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 5 μm, the particle size of the kaolin powder is 25 μm, and the specification size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. Firstly, ρ-Al with a mass percentage of 23.5% 2 o 3 powder, 26.5% kaolin powder for mixing and batching, adding deionized water with 150% of the total mass of raw materials, stirring in a mechanical stirrer and ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then adding a mass percentage of 50% % mullite fiber is evenly added to the ceramic slurry, and the stirring and vibration are continued for 30 minutes to obtain a gel-type ceramic-fiber slurry, which is then injection molded and solidified at room temperature, and the molded green body is placed in a 70°C Dry in a constant temperature drying oven for 96 hours, place in a high-temp...

Embodiment 2

[0024] In this example, the raw material adopts ρ-Al 2 o 3 powder, kaolin powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 3 μm, the particle size of the kaolin powder is 45 μm, and the specification size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. First, ρ-Al with a mass percentage of 15.7% 2 o 3 powder, 17.7% kaolin powder for mixing and batching, adding deionized water with 170% of the total mass of raw materials, stirring in a mechanical stirrer and ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then adding a mass percentage of 66.6 % mullite fiber is evenly added to the ceramic slurry, and the stirring and vibration are continued for 30 minutes to obtain a gel-type ceramic-fiber slurry, which is then injection molded and solidified at room temperature, and the molded green body is placed in a 70°C Dry it in a constant temperature drying oven for 72 hours, place it in a high...

Embodiment 3

[0027] In this example, the raw material adopts ρ-Al 2 o 3 powder, zircon powder and mullite fiber, ρ-Al 2 o 3 The particle size of the powder is 10 μm, the particle size of the zircon powder is 45 μm, and the standard size range of the mullite fiber is 5-10 μm in diameter and 50-125 μm in length. Firstly, ρ-Al with a mass percentage of 11.9% 2 o 3 powder, 13.1% zircon powder for mixing and batching, adding deionized water with 160% of the total mass of raw materials, stirring in a mechanical stirrer and performing ultrasonic oscillation for 5 minutes to obtain a stable and uniform ceramic slurry, and then the mass percentage Add 75% mullite fiber evenly into the ceramic slurry, continue to stir and vibrate for 30 minutes to obtain a gel-type ceramic-fiber slurry, then injection mold and solidify at room temperature, and mold the green body at 70 ℃ in a constant temperature drying oven for 48 hours, after demoulding, put it in a high-temperature furnace and sinter at a te...

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