Low-carbon alumina-magnesia carbon brick and preparation method thereof

Abstract

The invention relates to a low-carbon alumina-magnesia carbon brick and a preparation method thereof. The low-carbon alumina-magnesia carbon brick is prepared from the following raw materials in parts by weight: 60-80 parts of brown aluminum oxide with the particle size of 2-5mm; 30-45 parts of brown fused alumina with the particle size of 0.088-2 mm; 20-30 parts of brown fused alumina with a particle size of less than 0.088 mm; 30 to 40 parts of bauxite; 15 to 20 parts of fused magnesite; 5-10 parts of crystalline flake graphite; 2-3 parts of aluminum powder; 1-3 parts of liquid thermosetting phenolic resin; 1-2 parts of a composite additive; 0.5 to 1 part of silicon powder; the composite additive is formed by compounding dolomite and industrial alumina. The slag corrosion resistance of the alumina-magnesia carbon brick can be improved by adjusting the content of brown fused alumina and bauxite, and the thermal shock resistance of the alumina-magnesia carbon brick can be improved by adding the composite additive.

Description

Technical Field

[0001] The invention relates to the technical field of refractory materials, and in particular to a low-carbon aluminum-magnesia-carbon brick and a preparation method thereof. Background Art

[0002] Alumina-magnesia carbon bricks refer to refractory products made of super-high-alumina bauxite or corundum sand, magnesia sand and flaky graphite as the main raw materials. Alumina-magnesia carbon bricks have the advantages of anti-erosion, anti-stripping, balanced erosion, safe use, less steel and slag adhesion, and easy unpacking.

[0003] However, due to the high carbon content of the current aluminum-magnesium-carbon brick, it is easily oxidized during use. With the development of clean steel smelting technology, traditional aluminum-magnesium-carbon bricks have a certain carbon-enhancing effect on molten steel during use, which brings certain difficulties to the smelting of certain steel grades. However, if the carbon content in aluminum-magnesium-carbon bricks is simply reduced, the slag resistance and thermal shock resistance of aluminum-magnesium-carbon bricks will deteriorate, affecting the use requirements. Summary of the invention

[0004] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide a low-carbon aluminum-magnesium-carbon brick and a preparation method thereof. The present invention can improve the slag erosion resistance of the aluminum-magnesium-carbon brick by adjusting the content of brown corundum and bauxite, and can improve the thermal shock resistance of the aluminum-magnesium-carbon brick by adding composite additives.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A low-carbon aluminum-magnesium carbon brick, wherein the low-carbon aluminum-magnesium carbon brick is made of the following raw materials in parts by weight:

[0007]

[0008]

[0009] The composite additive is composited from dolomite and industrial alumina.

[0010] The particle sizes of the bauxite, fused magnesia, flake graphite, aluminum powder and silicon powder are all less than 0.088 mm.

[0011] The Al2O3 content of the brown corundum is ≥95%; the Al2O3 content of the bauxite is ≥90%; the MgO content of the fused magnesia is ≥97%; and the fixed carbon content of the flake graphite is ≥97%.

[0012] A method for preparing a low-carbon aluminum-magnesium-carbon brick comprises the following steps:

[0013] 1) Weigh the ingredients according to the above ratio, add brown corundum with a particle size of 2 to 5 mm, bauxite and fused magnesia into a mixer, and mix for 3 to 5 minutes;

[0014] 2) adding liquid thermosetting phenolic resin to the mixture of step 1) and mixing for 2 to 3 minutes;

[0015] 3) adding brown corundum with a particle size of 0.088 to 2 mm, aluminum powder, flake graphite, and silicon powder to the mixture of step 2) and mixing for 5 to 10 minutes;

[0016] 4) adding brown corundum with a particle size of less than 0.088 mm and the composite additive to the mixture in step 3) and mixing for 2 to 3 minutes;

[0017] 5) Finally, the mixed finished product is molded and fired.

[0018] In the step 5), a hydraulic forming machine is used to press the bricks into green bricks, and the green bricks are placed on a kiln car and subjected to heat treatment at 210-230° C. for 12-18 hours.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention can generate Al2O3 and MgAl2O4 and produce volume expansion by adding antioxidant metal aluminum powder, filling the pores and effectively preventing the oxidation of graphite. Since the presence of graphite increases the wetting angle between the brick and the slag, hindering the penetration of the slag into the brick, the slag erosion resistance of the brick is significantly improved. In addition, by increasing the content of brown corundum and reducing the content of bauxite, the resulting crystals are large, the crystals are tightly connected, the impurity content is low, and it is relatively stable at high temperatures, which is conducive to improving the slag erosion resistance of aluminum-magnesium-carbon bricks.

[0021] (2) The composite additive of the present invention is composed of dolomite and industrial alumina. The component of the composite additive is calcium aluminate-magnesium aluminum spinel, which can reduce the thermal expansion coefficient and is beneficial to improving the thermal shock resistance of aluminum-magnesium carbon bricks.

[0022] (3) The present invention adds a certain amount of Si powder to generate SiC which can block the channels or fill the pores, thereby densifying the surface layer structure of the material, thereby reducing the effective contact area between water vapor and the material and improving its anti-hydration performance; and the high-temperature phase 2MgO·SiO2 generated by the reaction can improve the density, strength and anti-hydration ability of the brick. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are further described below:

[0024] Example 1

[0025] A low-carbon aluminum-magnesium carbon brick, wherein the low-carbon aluminum-magnesium carbon brick is made of the following raw materials in parts by weight:

[0026]

[0027] The composite additive is composited from dolomite and industrial alumina.

[0028] The particle sizes of the bauxite, fused magnesia, flake graphite, aluminum powder and silicon powder are all less than 0.088 mm.

[0029] The Al2O3 content of the brown corundum is ≥95%; the Al2O3 content of the bauxite is ≥90%; the MgO content of the fused magnesia is ≥97%; and the fixed carbon content of the flake graphite is ≥97%.

[0030] A method for preparing a low-carbon aluminum-magnesium-carbon brick comprises the following steps:

[0031] 1) Weigh the ingredients according to the above ratio, add brown corundum with a particle size of 2 to 5 mm, bauxite and fused magnesia into a mixer, and mix for 3 minutes;

[0032] 2) adding liquid thermosetting phenolic resin to the mixture of step 1) and mixing for 2 minutes;

[0033] 3) Add brown corundum with a particle size of 0.088-2 mm, aluminum powder, flake graphite, and silicon powder to the mixture of step 2) and mix for 8 minutes;

[0034] 4) adding brown corundum with a particle size of less than 0.088 mm and the composite additive to the mixture in step 3) and mixing for 2 minutes;

[0035] 5) Finally, the mixed finished product is molded and fired.

[0036] In the step 5), a hydraulic forming machine is used to press the bricks into green bricks, and the green bricks are placed on a kiln car and subjected to heat treatment at 230° C. for 15 hours.

[0037] Example 2

[0038] A low-carbon aluminum-magnesium carbon brick, wherein the low-carbon aluminum-magnesium carbon brick is made of the following raw materials in parts by weight:

[0039]

[0040]

[0041] The composite additive is composited from dolomite and industrial alumina.

[0042] The particle sizes of the bauxite, fused magnesia, flake graphite, aluminum powder and silicon powder are all less than 0.088 mm.

[0043] The Al2O3 content of the brown corundum is ≥95%; the Al2O3 content of the bauxite is ≥90%; the MgO content of the fused magnesia is ≥97%; and the fixed carbon content of the flake graphite is ≥97%.

[0044] A method for preparing a low-carbon aluminum-magnesium-carbon brick comprises the following steps:

[0045] 1) Weigh the ingredients according to the above ratio, add brown corundum with a particle size of 2 to 5 mm, bauxite and fused magnesia into a mixer, and mix for 3 minutes;

[0046] 2) adding liquid thermosetting phenolic resin to the mixture of step 1) and mixing for 2 minutes;

[0047] 3) Add brown corundum with a particle size of 0.088-2 mm, aluminum powder, flake graphite, and silicon powder to the mixture of step 2) and mix for 8 minutes;

[0048] 4) adding brown corundum with a particle size of less than 0.088 mm and the composite additive to the mixture in step 3) and mixing for 2 minutes;

[0049] 5) Finally, the mixed finished product is molded and fired.

[0050] In the step 5), a hydraulic forming machine is used to press the bricks into green bricks, and the green bricks are placed on a kiln car and subjected to heat treatment at 230° C. for 15 hours.

[0051] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further explain various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A low carbon aluminum-magnesium-carbon brick, characterized in that: The low carbon aluminum magnesium carbon brick is made of the following raw materials in parts by weight: The composite additive is composited from dolomite and industrial alumina.

2. A low carbon aluminum-magnesium-carbon brick according to claim 1, characterized in that: The particle sizes of the bauxite, fused magnesia, flake graphite, aluminum powder and silicon powder are all less than 0.088 mm.

3. A low carbon aluminum-magnesium-carbon brick according to claim 1, characterized in that: The Al2O3 content of the brown corundum is ≥95%; the Al2O3 content of the bauxite is ≥90%; the MgO content of the fused magnesia is ≥97%; and the fixed carbon content of the flake graphite is ≥97%.

4. A method for preparing a low-carbon aluminum-magnesium-carbon brick according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Weigh the ingredients according to the above ratio, add brown corundum with a particle size of 2 to 5 mm, bauxite and fused magnesia into a mixer, and mix for 3 to 5 minutes; 2) adding liquid thermosetting phenolic resin to the mixture of step 1) and mixing for 2 to 3 minutes; 3) adding brown corundum with a particle size of 0.088 to 2 mm, aluminum powder, flake graphite, and silicon powder to the mixture of step 2) and mixing for 5 to 10 minutes; 4) adding brown corundum with a particle size of less than 0.088 mm and the composite additive to the mixture in step 3) and mixing for 2 to 3 minutes; 5) Finally, the mixed finished product is molded and fired.

5. The method for preparing a low-carbon aluminum-magnesium-carbon brick according to claim 4, characterized in that: In the step 5), a hydraulic forming machine is used to press the bricks into green bricks, and the green bricks are placed on a kiln car and subjected to heat treatment at 210-230° C. for 12-18 hours.

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