A periclase spinel carbon brick for RH refining furnace and its preparation method

Abstract

This invention relates to the field of refractory materials technology, and discloses a magnesia-spinel carbon brick for RH refining furnaces and its preparation method. This low-carbon brick is made from mixed granular materials, magnesia-alumina spinel powder, etc., through a mixing, molding, and baking process. The low-carbon brick of this invention exhibits strong slag penetration resistance and good thermal shock resistance. High-density fused magnesia has good slag resistance and hydration resistance, while large-grain fused magnesia has good erosion resistance. High-purity, high-density large-grain fused magnesia requires high-quality raw materials and high-temperature melting; therefore, the selection of granular materials should be based on different application requirements, choosing appropriate fused magnesia. Fused magnesia-alumina spinel has good slag penetration resistance and thermal shock resistance. Furthermore, the matrix portion uses magnesia-alumina spinel micro-powder instead of magnesia powder, reducing the reaction rate between magnesium oxide and carbon above 1600℃ and improving the high-temperature resistance of the product.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, specifically to a periclase spinel carbon brick for RH refining furnace and its preparation method. Background Technology

[0002] Currently, the RH vacuum refining furnace is the dominant technology in ladle refining processes, and this technology has developed rapidly. The RH refining furnace utilizes a vacuum circulation degassing method, employing the bubble pump effect to drive the circulation of molten steel, achieving refining functions such as degassing and decarburization in a vacuum environment. Commonly used refractory materials include high-temperature fired magnesia-chrome bricks and unfired magnesia-alumina spinel bricks, which possess high-temperature stability, erosion resistance, and good thermal shock resistance. However, with the development of high-temperature smelting technology and increasingly stringent environmental protection requirements, RH vacuum refining furnaces need bricks with superior performance to replace magnesia-chrome bricks and magnesia-alumina spinel bricks.

[0003] Magnesia-spinel carbon bricks possess excellent thermal shock resistance, resistance to molten steel erosion, and resistance to steel slag corrosion, making them suitable for intermittent production and extending service life and efficiency requirements in RH refining furnaces. Chinese patent document CN118812241A discloses a method for preparing unfired magnesia-alumina spinel bricks for impregnated tubes in RH refining furnaces. By adding composite additives and then mixing, rolling, pressing, and baking, unfired magnesia-alumina spinel bricks are obtained, exhibiting excellent corrosion resistance, high-temperature resistance, and wear resistance, and can replace magnesia-chrome bricks in RH refining furnace production. However, with the increasing variety of refined steels and changes in smelting processes, especially prolonged high-temperature and high-intensity production, problems such as spalling and damage at the top of the circulating tube bricks and circumferential cracks appearing in impregnated tube bricks in the later stages of use have emerged. Therefore, how to further improve the thermal shock resistance, resistance to molten steel erosion, and resistance to steel slag corrosion of magnesia-alumina spinel bricks by introducing additives such as carbon black powder and boron carbide powder is a problem that needs to be solved. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide a periclase spinel carbon brick for RH refining furnace and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions: A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: The mixture consists of 67-95 parts of granular material, 13-20 parts of magnesium aluminum spinel powder, 3-6 parts of metallic aluminum powder, 0.05-1 part of carbon black, 0.1-3 parts of titanium dioxide micro powder, 0.1-1 part of boron carbide micro powder, 0.3-1 part of phenolic resin powder, and 2-3 parts of liquid phenolic resin.

[0006] As a further embodiment of the present invention, the mixed granular material is composed of fused magnesia or magnesium aluminum spinel with a particle size of 3-6 mm, fused magnesia or magnesium aluminum spinel with a particle size of 1-3 mm, and fused magnesia or magnesium aluminum spinel with a particle size of 0.1-1 mm, in a mass ratio of 7-15:30-40:30-40.

[0007] As a further aspect of the present invention, the fused magnesia with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm has an MgO content ≥ 97.8 wt%, a SiO2 content ≤ 0.5 wt%, a CaO content ≤ 1.0 wt%, and a bulk density ≥ 3.50 g / cm³. 3 Magnesium aluminum spinel with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm has an Al₂O₃ content ≥ 48 wt%, an MgO content of 35 wt%-52 wt%, a CaO content ≤ 0.7 wt%, a SiO₂ content ≤ 0.5 wt%, and a bulk density ≥ 3.30 g / cm³. 3 .

[0008] As a further aspect of the present invention, the magnesium aluminum spinel powder contains 35wt%-52wt% MgO and 48wt%-65wt% Al2O3.

[0009] As a further embodiment of the present invention, the particle size of the magnesium aluminum spinel powder is 325 mesh; the particle size of the metallic aluminum powder is 325 mesh; the particle size of the boron carbide micro powder is 325 mesh; the particle size of the titanium dioxide micro powder is 325 mesh; the particle size of the carbon black is 325 mesh; and the particle size of the phenolic resin powder is 100 mesh.

[0010] A method for preparing periclase spinel carbon bricks for RH refining furnaces includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir at a speed of 100-200 r / min until evenly mixed. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 800-1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0011] The beneficial effects of this invention are: The perforated magnesia-spinel carbon brick for RH refining furnaces of this invention has several advantages. First, perforated magnesia-spinel exhibits a dual-solid phase at 1700℃, resulting in excellent high-temperature performance, strong resistance to slag penetration, and good thermal shock resistance. High-density fused magnesia has good slag resistance and hydration resistance, while large-grain fused magnesia has good erosion resistance. However, high-purity, high-density large-grain fused magnesia requires high-quality raw materials for high-temperature melting, which is energy-intensive and resource-limited. Therefore, the selection of granular materials should be based on different application requirements. Second, the matrix uses magnesium aluminate spinel micro-powder instead of magnesia powder, reducing the reaction rate between magnesium oxide and carbon above 1600℃, improving the high-temperature resistance of the product. Adding a small amount of carbon black effectively improves the thermal shock stability of the brick. Similarly, boron carbide is typically oxidized at 420℃, which can inhibit oxidation damage to the carbon structure. Boron carbide oxidizes to B₂O₃, which, under specific conditions, reacts with carbon black and titanium dioxide to form titanium diboride. Titanium diboride exhibits good resistance to slag corrosion. The slurry, when mixed with a small amount of solid resin powder and liquid phenolic resin, shows good stability and strengthens the carbon bonding of the matrix. Aluminum powder can reduce titanium dioxide to titanium dioxide, forming alumina. Alumina reacts with magnesium oxide to produce a spinel bonding phase. Under specific conditions, aluminum and titanium react with carbon and nitrogen to form compounds that enhance the matrix's erosion resistance and corrosion resistance. Therefore, periclase-spinel carbon bricks possess excellent thermal shock stability, resistance to molten steel erosion, and resistance to steel slag corrosion.

[0012] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Detailed Implementation

[0013] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Example 1 A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: 10 parts of fused magnesia with a particle size of 3-6 mm, 39 parts of fused magnesia with a particle size of 1-3 mm, 33 parts of magnesium aluminum spinel with a particle size of 0.1-3 mm, 13 parts of magnesium aluminum spinel powder, 3 parts of metallic aluminum powder, 0.2 parts of carbon black, 1 part of titanium dioxide micro powder, 0.3 parts of boron carbide micro powder, 0.5 parts of phenolic resin powder, and 2.5 parts of liquid phenolic resin; The method for preparing the carbon brick includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir and mix them evenly at a speed of 150 r / min. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0015] Among the fused magnesia with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm, the MgO content is ≥97.8 wt%, the SiO2 content is ≤0.5 wt%, the CaO content is ≤1.0 wt%, and the bulk density is ≥3.50 g / cm³. 3 Magnesium aluminum spinel with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm has an Al₂O₃ content ≥ 48 wt%, an MgO content of 35 wt%-52 wt%, a CaO content ≤ 0.7 wt%, a SiO₂ content ≤ 0.5 wt%, and a bulk density ≥ 3.30 g / cm³. 3 The magnesium aluminum spinel powder contains 35wt%-52wt% MgO and 48wt%-65wt% Al2O3. The particle size of the magnesium aluminum spinel powder is 325 mesh. The particle size of the metallic aluminum powder is 325 mesh. The particle size of the boron carbide micro powder is 325 mesh. The particle size of the titanium dioxide micro powder is 325 mesh. The particle size of the carbon black is 325 mesh, and the type is N330. The phenolic resin powder is type 4012 solid phenolic resin powder with a particle size of 100 mesh. All other components are the same.

[0016] Example 2 A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: 10 parts of fused magnesia with a particle size of 3-6 mm, 39 parts of fused magnesia with a particle size of 1-3 mm, 28 parts of fused magnesia with a particle size of 0.1-3 mm, 5 parts of magnesium aluminum spinel with a particle size of 0.1-3 mm, 13 parts of magnesium aluminum spinel powder, 3 parts of metallic aluminum powder, 0.2 parts of carbon black, 1 part of titanium dioxide micro powder, 0.3 parts of boron carbide micro powder, 0.5 parts of phenolic resin powder, and 2.5 parts of liquid phenolic resin; The method for preparing the carbon brick includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir and mix them evenly at a speed of 150 r / min. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0017] Example 3 A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: 10 parts of fused magnesia with a particle size of 3-6 mm, 39 parts of fused magnesia with a particle size of 1-3 mm, 23 parts of fused magnesia with a particle size of 0.1-3 mm, 10 parts of magnesium aluminum spinel with a particle size of 0.1-3 mm, 13 parts of magnesium aluminum spinel powder, 3 parts of metallic aluminum powder, 0.2 parts of carbon black, 1 part of titanium dioxide micro powder, 0.3 parts of boron carbide micro powder, 0.5 parts of phenolic resin powder, and 2.5 parts of liquid phenolic resin; The method for preparing the carbon brick includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir and mix them evenly at a speed of 150 r / min. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0018] Example 4 A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: 11 parts of fused magnesia with a particle size of 3-6 mm, 37 parts of fused magnesia with a particle size of 1-3 mm, 31 parts of fused magnesia with a particle size of 0.1-3 mm, 16 parts of magnesium aluminum spinel powder, 3.5 parts of metallic aluminum powder, 0.2 parts of carbon black, 0.5 parts of titanium dioxide micro powder, 0.3 parts of boron carbide micro powder, 0.5 parts of phenolic resin powder, and 2.5 parts of liquid phenolic resin; The method for preparing the carbon brick includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir and mix them evenly at a speed of 150 r / min. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0019] Example 5 A periclase spinel carbon brick for an RH refining furnace comprises the following raw materials measured in parts by weight: 11 parts of magnesium aluminum spinel with a particle size of 3-6 mm, 37 parts of magnesium aluminum spinel with a particle size of 1-3 mm, 31 parts of magnesium aluminum spinel with a particle size of 0.1-3 mm, 16 parts of magnesium aluminum spinel powder, 3.5 parts of metallic aluminum powder, 0.2 parts of carbon black, 0.5 parts of titanium dioxide micro powder, 0.3 parts of boron carbide micro powder, 0.5 parts of phenolic resin powder, and 2.5 parts of liquid phenolic resin; The method for preparing the carbon brick includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir and mix them evenly at a speed of 150 r / min. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

[0020] Test case According to standard GB / T 7321, the various properties of the carbon bricks in the examples and comparative examples were tested, and the results are recorded in the table below:

[0021] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

[0022] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A periclase spinel carbon brick for an RH refining furnace, characterized in that, Includes the following raw materials measured in parts by weight: The mixture consists of 67-95 parts of granular material, 13-20 parts of magnesium aluminum spinel powder, 3-6 parts of metallic aluminum powder, 0.05-1 part of carbon black, 0.1-3 parts of titanium dioxide micro powder, 0.1-1 part of boron carbide micro powder, 0.3-1 part of phenolic resin powder, and 2-3 parts of liquid phenolic resin.

2. The periclase spinel carbon brick for an RH refining furnace according to claim 1, characterized in that, The mixed granular material is composed of fused magnesia or magnesium aluminum spinel with a particle size of 3-6 mm, fused magnesia or magnesium aluminum spinel with a particle size of 1-3 mm, and fused magnesia or magnesium aluminum spinel with a particle size of 0.1-1 mm, with a mass ratio of 7-15:30-40:30-40.

3. The periclase spinel carbon brick for an RH refining furnace according to claim 2, characterized in that, The fused magnesia with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm has the following composition: MgO content ≥ 97.8 wt%, SiO2 content ≤ 0.5 wt%, CaO content ≤ 1.0 wt%, and bulk density ≥ 3.50 g / cm³. 3 Magnesium aluminum spinel with particle sizes of 3-6 mm, 1-3 mm, and 0.1-1 mm has an Al₂O₃ content ≥ 48 wt%, an MgO content of 35 wt%-52 wt%, a CaO content ≤ 0.7 wt%, a SiO₂ content ≤ 0.5 wt%, and a bulk density ≥ 3.30 g / cm³. 3 .

4. The periclase spinel carbon brick for an RH refining furnace according to claim 1, characterized in that, The magnesium aluminum spinel powder has a particle size of 325 mesh, an MgO content of 35wt%-52wt%, and an Al2O3 content of 48wt%-65wt%.

5. The periclase spinel carbon brick for an RH refining furnace according to claim 1, characterized in that, The magnesium aluminum spinel powder has a particle size of 325 mesh; the aluminum powder has a particle size of 325 mesh; the boron carbide micro powder has a particle size of 325 mesh; the titanium dioxide micro powder has a particle size of 325 mesh; the carbon black has a particle size of 325 mesh; and the phenolic resin powder has a particle size of 100 mesh.

6. A method for preparing periclase spinel carbon bricks for RH refining furnaces as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh and prepare all raw materials according to their respective weight proportions; Step 2: First, add the granular material and liquid phenolic resin to the mixer and mechanically stir at a speed of 100-200 r / min until evenly mixed. Then, add magnesium aluminum spinel powder, metallic aluminum powder, carbon black, titanium dioxide micro powder, boron carbide micro powder, and solid resin powder. After adding, adjust the speed to 800-1000 r / min and mix evenly. Finally, use a friction brick press to press the mixed mud into shape, and then bake it in a roller kiln and inspect it on an automatic packaging line.

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