All-fiber lightweight fire-resistant chute cover and its preparation process

Abstract

This invention discloses a lightweight, all-fiber refractory chute cover and its manufacturing process. The chute cover body includes a skeleton and a working layer covering the skeleton. The skeleton consists of an arc-shaped steel mesh and anchors welded inside the steel mesh. The working layer is made of refractory fiber and aluminum dihydrogen phosphate, and the inner arc surface of the working layer is sprayed with a nano-silicon carbide coating. The chute cover of this invention uses a steel mesh and V-shaped anchors to form a three-dimensional channel, which facilitates the discharge of moisture during baking and prevents blistering and cracking. The working layer uses aluminum silicate fiber, high-alumina fiber, or zirconium-containing high-alumina fiber refractory fiber, which has good thermal stability, withstands at least 100 thermal shock cycles, and is not easily peeled off. The surface is sprayed with a nano-silicon carbide coating, which enhances slag resistance, provides high hardness, wear resistance, and erosion resistance, and can withstand long-term impact from high-temperature gases, significantly extending its service life. The chute cover of this invention abandons the traditional aggregate plus powder structure, using all-fiber lightweight material, which has low density, excellent thermal insulation, low load, and stable performance.

Description

Technical Field

[0001] This invention relates to the field of refractory components for high-temperature industrial use, specifically to a lightweight all-fiber refractory chute cover and its manufacturing process. Background Technology

[0002] A chute cover is a protective and sealing cover placed on top of a chute, commonly used in non-ferrous metallurgy, metallurgy, and building materials industries. Its functions include: 1. Preventing material splashing, personnel falls, and debris from affecting flow; 2. Enclosing dust and reducing fugitive emissions; 3. Providing thermal insulation, reducing heat loss, providing heating and insulation, and preventing burns; 4. Allowing for inspection, unclogging, and maintenance of the lining; 5. Resisting thermal shock. Traditional chute covers often use heavy or lightweight castable refractories, which have the following drawbacks: 1. Simple frame structure, making it difficult for internal moisture to escape during baking, leading to cracking and deformation; 2. Traditional castable refractories are mainly composed of aggregate and powder, resulting in high density, poor insulation, and insufficient thermal shock resistance; 3. High labor intensity for workers and difficulty in replacement; 4. Although hollow alumina spheres have a lower bulk density, their high cost limits their widespread application. Currently, the density of finished chute covers made from hollow alumina spheres is only 1.3-1.7, clearly failing to meet the requirements for lightweight construction. In order to overcome the problems of existing chute covers, such as high density, poor thermal insulation, weak thermal shock resistance, easy erosion damage, and easy cracking during molding, it is urgent to develop a new type of chute cover that is lightweight, high-strength, high-temperature resistant, fire-resistant, thermal shock resistant, and erosion resistant. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of high density, poor thermal insulation, weak thermal shock resistance, easy erosion damage, and easy cracking in the existing chute cover plate, and to provide a lightweight all-fiber refractory chute cover plate and its preparation process.

[0004] The technical solution adopted in this invention is: a lightweight, all-fiber refractory chute cover, comprising a chute cover body, a burner hole on the chute cover body, and a handle on the top of the chute cover body. The chute cover body includes a skeleton and a working layer covering the skeleton. The skeleton is composed of an arc-shaped steel mesh and anchors welded inside the steel mesh. The working layer is made of refractory fiber, aluminum dihydrogen phosphate, and a composite binder. The inner arc surface of the working layer is sprayed with a nano-silicon carbide coating. The refractory fiber is any one or more of aluminum silicate fiber, high-alumina fiber, and zirconium-containing high-alumina fiber.

[0005] As a further optimization of the all-fiber lightweight fire-resistant chute cover of the present invention, the thickness of the steel mesh is 3-5mm.

[0006] As a further optimization of the all-fiber lightweight fire-resistant chute cover of the present invention, the anchor is a V-shaped stainless steel anchor nail.

[0007] As a further optimization of the all-fiber lightweight fire-resistant chute cover of the present invention, the thickness of the working layer is 20-800 mm, and the bulk density of the working layer does not exceed 1200 kg / m³. 3 .

[0008] As a further optimization of the all-fiber lightweight fire-resistant chute cover of the present invention, the thickness of the nano-silicon carbide coating does not exceed 5 mm.

[0009] As a further optimization of the all-fiber lightweight refractory chute cover of the present invention, 20-50 kg of aluminum dihydrogen phosphate aqueous solution is added to each ton of refractory fiber, and the mass fraction of aluminum dihydrogen phosphate aqueous solution is 50%.

[0010] As a further optimization of the all-fiber lightweight refractory chute cover of the present invention, the composite binder comprises, by weight, 0.2-0.3 parts of sodium hexametaphosphate, 0.15-0.25 parts of sodium carboxymethyl cellulose, 0.04-0.06 parts of lithium carbonate, and 0.08-0.12 parts of organosilicon defoamer; and 4.2-7.3 kg of composite binder is added per ton of refractory fiber.

[0011] The manufacturing process of the all-fiber lightweight fire-resistant chute cover includes the following steps: S1. Process the steel mesh into an arc shape, and weld anchors inside the steel mesh to form a skeleton; S2. Add refractory fiber, aluminum dihydrogen phosphate and composite binder to the aqueous solution, stir evenly to obtain fiber lightweight slurry; S3. Place the skeleton in the mold, add the fiber lightweight slurry, cover the skeleton, and form the working layer by vacuum suction filtration. S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, and then at 150-200℃ for more than 12 hours. Next, the temperature is raised to 300℃ and held for 24-72 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking, and then naturally cooled to obtain a full-fiber lightweight fire-resistant chute cover plate.

[0012] As a further optimization of the preparation process of the all-fiber lightweight refractory chute cover of the present invention, the fiber lightweight slurry described in step S3 is fixedly wrapped on the skeleton in a three-dimensional state after being integrally formed by vacuum filtration.

[0013] As a further optimization of the preparation process of the all-fiber lightweight fire-resistant chute cover of the present invention, the nano silicon carbide coating in step S5 is formed by spraying after mixing nano-sized silicon carbide powder with a binder, and the binder is silica sol or aluminum sol; the ratio of nano-sized silicon carbide powder to binder is 1:5.5-6.5.

[0014] Compared with the prior art, the present invention has the following beneficial effects: I. The chute cover plate disclosed in this invention adopts a steel mesh + V-shaped anchor nail to form a three-dimensional channel, which is conducive to the discharge of moisture during baking and is not easy to blister or crack. The working layer is made of aluminum silicate refractory fiber, which has good thermal stability, resists thermal shock cycles of no less than 100 times, and has a thermal conductivity that is significantly lower than that of aggregate plus powder chute cover plates, which is far superior to traditional castables and is not easy to peel off. The surface of the chute cover plate is sprayed with a nano silicon carbide coating to enhance slag resistance, hardness, wear resistance, and erosion resistance. It can withstand long-term impact of high temperature gas and significantly extend its service life.

[0015] II. The chute cover of this invention abandons the traditional aggregate plus powder structure and adopts a lightweight all-fiber material with low density, excellent thermal insulation, and low load. The preparation process of this invention is stable and simple, resulting in a cover with stable performance and strong bonding. The waste heat is used for thermal spraying of a nano-silicon carbide coating, which adheres firmly to the working surface. The process is compact and suitable for industrial production, and can be widely used in the protection of high-temperature chutes in metallurgy, building materials, chemical and other fields. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the chute cover plate of the present invention; Figure 2 This is a schematic diagram of the skeleton of the chute cover plate of the present invention; Figure 3 This is a partial enlarged view of part A of the chute cover plate of the present invention; Reference numerals: 1. Burner hole, 2. Handle, 3. Working layer, 4. Steel mesh, 5. Anchor, 6. Nano silicon carbide coating. Detailed Implementation

[0017] 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.

[0018] like Figure 1-3As shown, a lightweight, all-fiber refractory chute cover includes a chute cover body with burner holes 1 and a handle 2 on the top. The chute cover body includes a skeleton and a working layer 3 covering the skeleton. The skeleton is composed of an arc-shaped steel mesh 4 and anchors 5 welded inside the steel mesh 4. The working layer 3 is made of refractory fiber, aluminum dihydrogen phosphate, and a composite binder. The inner arc surface of the working layer 3 is sprayed with a nano-silicon carbide coating 6. The refractory fiber is any one or more of aluminum silicate fiber, high-alumina fiber, and zirconium-containing high-alumina fiber.

[0019] To improve the implementation effect of the chute cover of the present invention, the thickness of the steel mesh is 3-5 mm. The thickness of the working layer is 20-800 mm, and the bulk density of the working layer does not exceed 1200 kg / m³. 3 The thickness of the nano-silicon carbide coating does not exceed 5 mm.

[0020] Furthermore, the anchor 5 is a V-shaped stainless steel anchor stud.

[0021] To improve the thermal stability of the working layer of this invention, 20-50 kg of an aqueous solution of aluminum dihydrogen phosphate is added per ton of the refractory fiber, with the aluminum dihydrogen phosphate aqueous solution having a mass fraction of 50%. The composite binder comprises, by weight, 0.2-0.3 parts of sodium hexametaphosphate, 0.15-0.25 parts of sodium carboxymethyl cellulose, 0.04-0.06 parts of lithium carbonate, and 0.08-0.12 parts of organosilicon defoamer; 4.2-7.3 kg of the composite binder is added per ton of refractory fiber.

[0022] The manufacturing process of the all-fiber lightweight fire-resistant chute cover includes the following steps: S1. Process the steel mesh into an arc shape, and weld anchors inside the steel mesh to form a skeleton; S2. Add refractory fiber, aluminum dihydrogen phosphate and composite binder to the aqueous solution, stir evenly to obtain fiber lightweight slurry; S3. Place the skeleton in the mold, add the lightweight fiber slurry to cover the skeleton, and then vacuum filter to form an integrated working layer; further, after vacuum filter and integrated molding, the lightweight fiber slurry is fixedly wrapped on the skeleton in a three-dimensional state.

[0023] S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, and then at 150-200℃ for more than 12 hours. Next, the temperature is raised to 300℃ and held for 24-72 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking, and then naturally cooled to obtain a full-fiber lightweight fire-resistant chute cover plate.

[0024] Furthermore, the nano-silicon carbide coating is formed by spraying nano-sized silicon carbide powder mixed with a binder, and the binder is silica sol or aluminum sol; the ratio of nano-sized silicon carbide powder to binder is 1:5.5-6.5.

[0025] Example 1:

[0026] A manufacturing process for a zirconium-containing high-alumina fiber lightweight refractory chute cover includes the following steps: S1. Process the steel mesh into an arc shape with a radius of curvature and an arch height of 300mm. The length of the chute cover is 500mm. A burner hole with a diameter of 80mm is reserved in the center. Weld anchors inside the steel mesh with a height of 20mm to form a skeleton. S2. Zirconium-containing high-alumina fiber, aluminum dihydrogen phosphate, and composite binder are added to an aqueous solution and stirred evenly to obtain a lightweight fiber slurry. The refractory fiber is a zirconium-containing high-alumina fiber. 20 kg of aluminum dihydrogen phosphate aqueous solution is added to each ton of refractory fiber. The aluminum dihydrogen phosphate aqueous solution is commercially available PA-80 aluminum dihydrogen phosphate. The composite binder comprises, by weight, 0.2 parts sodium hexametaphosphate, 0.15 parts sodium carboxymethyl cellulose, 0.04 parts lithium carbonate, and 0.08 parts organosilicon defoamer. 4.2 kg of composite binder is added to each ton of refractory fiber. S3. Place the skeleton in the mold, add the lightweight fiber slurry to cover the skeleton, and then vacuum filter to form an integrated working layer; after vacuum filtration and integrated forming, the lightweight fiber slurry is fixedly wrapped on the skeleton in a three-dimensional state. S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, then at 150-200℃ for 24 hours, then heated to 300℃ and held for 24 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking. The nano-silicon carbide coating is formed by spraying a mixture of nano-sized silicon carbide powder and a binder. The binder is silica sol or aluminum sol. The ratio of nano-sized silicon carbide powder to binder is 1:5.5. Natural cooling yields a full-fiber lightweight refractory chute cover plate.

[0027] In this embodiment, the working layer 3 of the all-fiber lightweight fire-resistant chute cover has a thickness of 20 mm, and the bulk density of the working layer 3 does not exceed 800 kg / m³. 3The thickness of the nano-silicon carbide coating 6 is 3mm; the length of the chute cover in this embodiment is 500mm, the radius of the arc and the height of the arch are both 300mm, and the diameter of the burner is 80mm.

[0028] Example 2:

[0029] A manufacturing process for a high-alumina fiber lightweight refractory chute cover includes the following steps: S1. Process the steel mesh into an arc shape with a radius of curvature and an arch height of 600mm. The length of the chute cover is 500mm. A burner hole with a diameter of 120mm is reserved in the center. Weld anchors inside the steel mesh with an anchor height of 120mm to form a skeleton. S2. High-alumina fiber, aluminum dihydrogen phosphate, and composite binder are added to an aqueous solution and stirred evenly to obtain a lightweight fiber slurry. 50 kg of aluminum dihydrogen phosphate aqueous solution is added to each ton of refractory fiber. The aluminum dihydrogen phosphate aqueous solution is commercially available PA-80 aluminum dihydrogen phosphate. The composite binder comprises, by weight, 0.25 parts sodium hexametaphosphate, 0.20 parts sodium carboxymethyl cellulose, 0.05 parts lithium carbonate, and 0.10 parts organosilicon defoamer. 6 kg of composite binder is added to each ton of refractory fiber. S3. Place the skeleton in the mold, add the lightweight fiber slurry to cover the skeleton, and then vacuum filter to form an integrated working layer; after vacuum filtration and integrated forming, the lightweight fiber slurry is fixedly wrapped on the skeleton in a three-dimensional state. S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, then at 150-200℃ for 12 hours, then the temperature is raised to 300℃ and held for 48 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking. The nano-silicon carbide coating is formed by spraying nano-sized silicon carbide powder mixed with a binder. The binder is silica sol or aluminum sol. The ratio of nano-sized silicon carbide powder to binder is 1:6.1. Natural cooling yields a full-fiber lightweight refractory chute cover plate.

[0030] In this embodiment, the working layer 3 of the all-fiber lightweight refractory chute cover has a thickness of 120 mm, and the bulk density of the working layer 3 does not exceed 600 kg / m³. 3 The thickness of the nano-silicon carbide coating 6 is 4mm; in this embodiment, the chute cover plate is 500mm long, the arc radius and the arch height are both 600mm, and the burner diameter is 120mm.

[0031] Example 3:

[0032] A manufacturing process for a lightweight refractory chute cover made of aluminosilicate fiber includes the following steps: S1. Process the steel mesh into an arc shape with a radius of curvature and an arch height of 1000mm. The chute cover is 600mm long. A burner hole with a diameter of 200mm is reserved in the center. Weld anchors inside the steel mesh with an anchor height of not less than 500mm to form a skeleton. S2. Refractory fibers, aluminum dihydrogen phosphate, and a composite binder are added to an aqueous solution and stirred evenly to obtain a lightweight fiber slurry. The refractory fibers are a mixture of equal weights of aluminosilicate fibers, high-alumina fibers, and zirconium-containing high-alumina fibers. 35 kg of aluminum dihydrogen phosphate aqueous solution is added to each ton of refractory fibers. The aluminum dihydrogen phosphate aqueous solution is commercially available PA-80 aluminum dihydrogen phosphate. The composite binder comprises, by weight, 0.3 parts sodium hexametaphosphate, 0.25 parts sodium carboxymethyl cellulose, 0.06 parts lithium carbonate, and 0.12 parts organosilicon defoamer. 7.3 kg of composite binder is added to each ton of refractory fibers. S3. Place the skeleton in the mold, add the lightweight fiber slurry to cover the skeleton, and then vacuum filter to form an integrated working layer; after vacuum filtration and integrated forming, the lightweight fiber slurry is fixedly wrapped on the skeleton in a three-dimensional state. S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, then at 150-200℃ for 12 hours, then the temperature is raised to 300℃ and held for 72 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking. The nano-silicon carbide coating is formed by mixing nano-sized silicon carbide powder with a binder and then spraying it. The binder is silica sol or aluminum sol. The ratio of nano-sized silicon carbide powder to binder is 1:6. Natural cooling yields a full-fiber lightweight refractory chute cover plate.

[0033] In this embodiment, the working layer 3 of the all-fiber lightweight refractory chute cover has a thickness of 800 mm, and the bulk density of the working layer 3 does not exceed 1200 kg / m³. 3 The thickness of the nano-silicon carbide coating 6 is 5mm; in this embodiment, the chute cover plate is 600mm long, the arc radius and the arch height are both 1000mm, and the burner diameter is 200mm.

[0034] The chute cover plate disclosed in this invention uses steel mesh and V-shaped anchor nails to form a three-dimensional channel, which facilitates the discharge of moisture during baking and is not prone to blistering or cracking. The working layer is made of aluminum silicate refractory fiber, which has good thermal stability. The main working layer can withstand no less than 100 thermal shock cycles, and its thermal conductivity is significantly lower than that of aggregate-powder chute cover plates. Its thermal shock stability is much better than that of traditional castables, and it is not easy to peel off. The surface of the chute cover plate is sprayed with a nano-silicon carbide coating, which enhances slag resistance, hardness, wear resistance, and erosion resistance. It can withstand long-term impact from high-temperature gases, and its service life is significantly extended. The chute cover plate of this invention abandons the traditional aggregate-powder structure and uses all-fiber lightweight material, which has low density, excellent thermal insulation effect, and low load. The preparation process of this invention is stable and simple. The resulting cover plate has stable performance and strong bonding force. The nano-silicon carbide coating is thermally sprayed using waste heat, and the coating is firmly bonded to the working surface. The process is compact and suitable for industrial production. It can be widely used in the protection of high-temperature chute plates in metallurgy, building materials, chemical and other fields.

[0035] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A lightweight, all-fiber refractory chute cover, comprising a chute cover body, wherein a burner hole (1) is provided on the chute cover body, and a handle (2) is provided on the top of the chute cover body, characterized in that: The chute cover body includes a skeleton and a working layer (3) covering the skeleton. The frame is composed of an arc-shaped steel mesh (4) and anchors (5) welded inside the steel mesh (4); The working layer (3) is made of refractory fiber, aluminum dihydrogen phosphate and composite binder, and the inner arc surface of the working layer (3) is sprayed with a nano silicon carbide coating (6). The refractory fiber is any one or more of aluminosilicate fiber, high-alumina fiber, and zirconium-containing high-alumina fiber.

2. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The thickness of the steel mesh (4) is 3-5 mm.

3. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The anchor (5) is a V-shaped stainless steel anchor.

4. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The thickness of the working layer (3) is 20-800 mm, and the bulk density of the working layer (3) does not exceed 1200 kg / m³. 3 .

5. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The thickness of the nano-silicon carbide coating (6) does not exceed 5 mm.

6. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The refractory fiber contains 20-50 kg of an aqueous solution of aluminum dihydrogen phosphate per ton, and the aluminum dihydrogen phosphate aqueous solution has a mass fraction of 50%.

7. The all-fiber lightweight fire-resistant chute cover as described in claim 1, characterized in that: The composite binder comprises, by weight, 0.2-0.3 parts sodium hexametaphosphate, 0.15-0.25 parts sodium carboxymethyl cellulose, 0.04-0.06 parts lithium carbonate, and 0.08-0.12 parts organosilicon defoamer; 4.2-7.3 kg of the composite binder is added per ton of refractory fiber.

8. The preparation process of the all-fiber lightweight fire-resistant chute cover as described in claims 1-7, characterized in that: Includes the following steps: S1. Process the steel mesh into an arc shape, and weld anchors inside the steel mesh to form a skeleton; S2. Add refractory fiber, aluminum dihydrogen phosphate and composite binder to the aqueous solution, stir evenly to obtain fiber lightweight slurry; S3. Place the skeleton in the mold, add the fiber lightweight slurry, cover the skeleton, and form the working layer by vacuum suction filtration. S4. After the working layer is vacuum filtered and formed, it is demolded and placed in an oven for gradual heating and baking. First, it is baked at 50-80℃ for 6 hours to dry free water; then it is baked at 80-150℃ for 6 hours, and then at 150-200℃ for more than 12 hours. Next, the temperature is raised to 300℃ and held for 24-72 hours to remove bound water; then it continues to bake until the moisture content of the cover plate does not exceed 1% and the temperature does not exceed 400℃. S5. Using residual heat, a nano-silicon carbide coating is sprayed onto the inner arc surface of the working layer of the cover plate after baking, and then naturally cooled to obtain a full-fiber lightweight fire-resistant chute cover plate.

9. The manufacturing process of a full-fiber lightweight fire-resistant chute cover as described in claim 8, characterized in that: The lightweight fiber slurry described in step S3 is vacuum filtered and integrally molded, and then fixedly coated onto the skeleton in a three-dimensional state.

10. The manufacturing process of a full-fiber lightweight fire-resistant chute cover as described in claim 8, characterized in that: The nano-silicon carbide coating described in step S5 is formed by spraying a mixture of nano-sized silicon carbide powder and a binder. The binder is either silica sol or aluminum sol. The ratio of nano-sized silicon carbide powder to binder is 1:5.5-6.5.

Images