Unburned aluminum-magnesium-carbon brick and its preparation method

Abstract

The application provides an unfired aluminum-magnesium-carbon brick and a preparation method thereof. The unfired aluminum-magnesium-carbon brick is prepared from the following components in parts by weight: 40-70 parts of brown corundum, 5-12 parts of fused magnesite, 4-7 parts of graphene oxide, 1-3 parts of aluminum powder, 0.5-2 parts of nano vanadium pentoxide, 0.5-1 part of active lime, and 2-4 parts of phenolic resin. The unfired aluminum-magnesium-carbon brick provided by the application has low porosity, high bulk density, high cold compressive strength and high thermal shock stability.

Description

Technical Field

[0001] This invention relates to the field of refractory brick technology, specifically to a non-fired alumina-magnesia-carbon brick and its preparation method. Background Technology

[0002] Unburned alumina-magnesia-carbon bricks were developed based on carbon-containing bricks such as magnesia-carbon bricks and alumina-carbon bricks, incorporating the characteristics of alumina-magnesia refractories. They combine the advantages of both carbon-containing and alumina-magnesia refractories. Unburned alumina-magnesia-carbon bricks possess good strength, low porosity, excellent erosion resistance, slag resistance, and good thermal shock stability, and are widely used in electric furnaces, converter linings, and steel ladles. In recent years, with the high-quality development of the steel industry, the performance requirements for unburned alumina-magnesia-carbon bricks have been continuously increasing.

[0003] With the high-quality development of the steel industry, the demand for high-quality steel is increasing, which places higher demands on the performance of refractory materials used for ladle linings. Traditional unburned alumina-magnesia-carbon bricks use graphite as a carbon source, and the large amount of graphite used can easily lead to a high carbon content in the molten steel, thus affecting the quality of steel products. Secondly, unburned alumina-magnesia-carbon bricks made from high-alumina bauxite often have poor slag resistance because high-alumina bauxite contains more SiO2 impurities than brown corundum. Therefore, how to obtain unburned alumina-magnesia-carbon bricks with better performance by improving the composition and ratio, and improving the preparation process, is an urgent problem to be solved. Summary of the Invention

[0004] To address the problems existing in the background art, the present invention provides a non-fired aluminum-magnesium-carbon brick and its preparation method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] In a first aspect, the present invention provides a non-fired aluminum-magnesium-carbon brick, which is made of the following components in parts by weight: 40-70 parts brown corundum, 5-12 parts fused magnesia, 4-7 parts graphene oxide, 1-3 parts metallic aluminum powder, 0.5-2 parts nano-sized vanadium pentoxide, 0.5-1 part active lime, and 2-4 parts phenolic resin.

[0007] According to the above scheme, the brown fused alumina is composed of brown fused alumina of different particle sizes in the following parts by weight: 20-40 parts of 5-3 mm brown fused alumina, 10-15 parts of 3-1 mm brown fused alumina, and 10-15 parts of brown fused alumina with a particle size of less than 200.

[0008] According to the above scheme, the content of aluminum oxide in the brown fused alumina is not less than 95%, and the content of magnesium oxide in the fused magnesia is not less than 97%.

[0009] According to the above scheme, the particle size of the aluminum powder is within 200 mesh, and the particle size of the active lime is within 200 mesh.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned non-fired aluminum-magnesium-carbon brick, comprising the following steps: S1. Batching: Weigh each raw material component according to the weight parts;

[0011] S2. Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin to 40-50°C, then mix the raw materials in a mixer and discharge them.

[0012] S3. Molding: The clay obtained after mixing is added into a steel mold and pressed to form a brick blank;

[0013] S4. Drying: The brick blank obtained in step S3 is baked and cured at 180-220℃ for 18-24 hours to obtain the unburned aluminum-magnesium-carbon brick.

[0014] According to the above scheme, the brown fused alumina is composed of brown fused alumina of different particle sizes in the following weight parts: 20-40 parts of 5-3mm brown fused alumina, 10-15 parts of 3-1mm brown fused alumina, and 10-15 parts of brown fused alumina within 200 mesh. During mixing, the 5-3mm and 3-1mm brown fused alumina and fused magnesia are first added to the mixer and stirred for 3-5 minutes to make them evenly mixed. Then, the 200-mesh brown fused alumina, graphene oxide, aluminum powder, nano-grade vanadium pentoxide, active lime and phenolic resin are added and mixed for 10-15 minutes before being discharged.

[0015] According to the above scheme, the rotation speed of the mixer in step S2 is 970 r / min.

[0016] According to the above scheme, the forming pressure in step S2 is 800-900t, and the bulk density of the resulting brick blank is 3.05-3.15g / cm³. 3 .

[0017] The beneficial effects of this invention are:

[0018] 1) The non-fired aluminum magnesium carbon brick of the present invention uses graphene oxide as a carbon source. The surface of graphene oxide contains a large number of oxygen-containing functional groups, which have excellent antioxidant properties. This can prevent the carbon in the non-fired aluminum magnesium carbon brick from forming pores after oxidation, thus avoiding erosion by molten slag and greatly improving the slag resistance of the material.

[0019] 2) Nano-grade vanadium pentoxide is used as one of the additives. Vanadium pentoxide has highly efficient catalytic properties and can convert carbon and sulfur into carbon dioxide and sulfur dioxide through a series of adsorption and redox reactions. Therefore, using the unburned alumina-magnesia-carbon brick of this invention as a ladle lining can effectively reduce the content of carbon and sulfur impurities in molten steel and improve the quality of steel products. Furthermore, nano-grade vanadium pentoxide can be partially embedded in the interlayer of graphene oxide at high temperatures, and the two have a strong interfacial bond. This composite material has excellent chemical stability, strong structural stability and mechanical properties, which can significantly reduce the stress generated when the refractory material undergoes volume changes, inhibit the growth and aggregation of microcracks, thereby improving the hardness and toughness of the material. The resulting unburned alumina-magnesia-carbon brick has higher strength and thermal shock resistance. In addition, this composite material also has excellent thermal conductivity. Using the unburned alumina-magnesia-carbon brick provided by this invention as a ladle lining can make the temperature of molten steel more uniform and can also improve the quality of steel products to a certain extent.

[0020] 3) Using active lime as one of the additives, an appropriate amount of CaO can react with SiO2 and Al2O3 under high temperature conditions to generate stable low-melting-point CaO-Al2O3-SiO2 compounds. These low-melting-point compounds can enter the pores, which can block the pores and increase the viscosity of the melt, significantly improving the slag resistance of the brick, promoting the sintering of the material, and contributing to the densification of the brick structure.

[0021] 4) The preparation method of the present invention uses readily available raw materials, has simple process steps, and does not require high-end production equipment, making it suitable for mass production. The resulting unburned alumina-magnesia-carbon bricks have low porosity, high bulk density, high room temperature compressive strength, and high thermal shock stability. Detailed Implementation

[0022] The principles and features of the present invention are described below with reference to specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0023] This invention provides a non-fired aluminum-magnesium-carbon brick, which is made of the following components in parts by weight: 40-70 parts brown corundum, 5-12 parts fused magnesia, 4-7 parts graphene oxide, 1-3 parts metallic aluminum powder, 0.5-2 parts nano-sized vanadium pentoxide, 0.5-1 part active lime, and 2-4 parts phenolic resin.

[0024] Preferably, the brown fused alumina is composed of the following parts by weight of brown fused alumina of different particle sizes: 20-40 parts of 5-3 mm brown fused alumina, 10-15 parts of 3-1 mm brown fused alumina, and 10-15 parts of brown fused alumina within 200 mesh.

[0025] Preferably, the content of aluminum oxide in the brown fused alumina is not less than 95%, and the content of magnesium oxide in the fused magnesia is not less than 97%.

[0026] Preferably, the particle size of the aluminum powder is less than 200 mesh, and the particle size of the activated lime is less than 200 mesh.

[0027] Secondly, the present invention provides a method for preparing the above-mentioned non-fired aluminum-magnesium-carbon brick, comprising the following steps: S1. Batching: Weigh each raw material component according to the weight parts;

[0028] S2. Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin to 40-50°C, then mix the raw materials in a mixer and discharge them.

[0029] S3. Molding: The clay obtained after mixing is added into a steel mold and pressed to form a brick blank;

[0030] S4. Drying: The brick blank obtained in step S3 is baked and cured at 180-220℃ for 18-24 hours to obtain the unburned aluminum-magnesium-carbon brick.

[0031] Preferably, during the mixing process, brown fused alumina with particle sizes of 5-3 mm and 3-1 mm and fused magnesia are first added to the mixer and stirred for 3-5 minutes to ensure uniform mixing. Then, brown fused alumina with a particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime, and phenolic resin are added and mixed for 10-15 minutes before being discharged.

[0032] Preferably, the speed of the mixer in step S2 is 970 r / min.

[0033] Preferably, the forming pressure in step S2 is 800–900 t, and the resulting brick blank has a bulk density of 3.05–3.15 g / cm³. 3 .

[0034] The following description is based on specific embodiments.

[0035] Example 1

[0036] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0037] 1) Ingredients: Accurately weigh 25 parts of 5-3mm brown fused alumina, 10 parts of 3-1mm brown fused alumina, 15 parts of brown fused alumina within 200 mesh, 6 parts of fused magnesia, 5 parts of graphene oxide, 1 part of metallic aluminum powder, 1 part of nano-grade vanadium pentoxide, 0.5 parts of active lime, and 3 parts of phenolic resin.

[0038] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0039] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 800t. The resulting brick blanks have a bulk density of 3.07g / cm³. 3 ;

[0040] 4) Drying: Bake the brick blank at 180℃ for 18 hours and let it cool naturally to room temperature before taking it out to obtain the brick.

[0041] In step 2), the mixing mill speed is 970 r / min.

[0042] Example 2

[0043] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0044] 1) Ingredients: Accurately weigh 32 parts of 5-3mm brown fused alumina, 11 parts of 3-1mm brown fused alumina, 14 parts of brown fused alumina within 200 mesh, 10 parts of fused magnesia, 7 parts of graphene oxide, 3 parts of metallic aluminum powder, 0.5 parts of nano-grade vanadium pentoxide, 0.6 parts of active lime, and 4 parts of phenolic resin.

[0045] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0046] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 800t. The resulting brick blanks have a bulk density of 3.12g / cm³. 3 ;

[0047] 4) Drying: The brick blanks are baked and cured at 200℃ for 22 hours, and then naturally cooled to room temperature before being taken out to obtain bricks.

[0048] In step 2), the mixing mill speed is 970 r / min.

[0049] Example 3

[0050] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0051] 1) Ingredients: Accurately weigh 30 parts of 5-3mm brown fused alumina, 12 parts of 3-1mm brown fused alumina, 13 parts of brown fused alumina within 200 mesh, 8 parts of fused magnesia, 6 parts of graphene oxide, 2 parts of metallic aluminum powder, 0.8 parts of nano-grade vanadium pentoxide, 0.7 parts of active lime, and 3 parts of phenolic resin.

[0052] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0053] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 900t. The resulting brick blanks have a bulk density of 3.15g / cm³. 3 ;

[0054] 4) Drying: Bake the brick blank at 200℃ for 24 hours to cure it. After naturally cooling to room temperature, take it out to obtain the brick.

[0055] In step 2), the mixing mill speed is 970 r / min.

[0056] Example 4

[0057] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0058] 1) Ingredients: Accurately weigh 22 parts of 5-3mm brown fused alumina, 12 parts of 3-1mm brown fused alumina, 15 parts of brown fused alumina within 200 mesh, 8 parts of fused magnesia, 5 parts of graphene oxide, 2 parts of metallic aluminum powder, 1.5 parts of nano-grade vanadium pentoxide, 0.8 parts of active lime, and 2 parts of phenolic resin.

[0059] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0060] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 900t. The resulting brick blanks have a bulk density of 3.12g / cm³. 3 ;

[0061] 4) Drying: Bake the brick blank at 240℃ for 20 hours to cure it. After naturally cooling to room temperature, take it out to obtain the brick.

[0062] In step 2), the mixing mill speed is 970 r / min.

[0063] Example 5

[0064] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0065] 1) Ingredients: Accurately weigh 35 parts of 5-3mm brown fused alumina, 13 parts of 3-1mm brown fused alumina, 12 parts of brown fused alumina within 200 mesh, 6 parts of fused magnesia, 4 parts of graphene oxide, 1 part of metallic aluminum powder, 2 parts of nano-grade vanadium pentoxide, 1 part of active lime, and 2 parts of phenolic resin.

[0066] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0067] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 900t. The resulting brick blanks have a bulk density of 3.13g / cm³. 3 ;

[0068] 4) Drying: Bake the brick blank at 220℃ for 18 hours and let it cool naturally to room temperature before taking it out to obtain the brick.

[0069] In step (2), the speed of the mixer is 970 r / min.

[0070] Example 6

[0071] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0072] 1) Ingredients: Accurately weigh 30 parts of 5-3mm brown fused alumina, 15 parts of 3-1mm brown fused alumina, 10 parts of brown fused alumina within 200 mesh, 12 parts of fused magnesia, 6 parts of graphene oxide, 3 parts of metallic aluminum powder, 1 part of nano-grade vanadium pentoxide, 0.7 parts of active lime, and 3 parts of phenolic resin.

[0073] 2) Mixing: Preheat brown fused alumina, fused magnesia, graphene oxide and phenolic resin of various particle sizes to 40-50℃. First, add brown fused alumina with particle sizes of 5-3mm and 3-1mm and fused magnesia to the mixer and stir for 3-5 minutes to make them evenly mixed. Then add brown fused alumina with particle size of less than 200 mesh, graphene oxide, aluminum powder, nano-sized vanadium pentoxide, active lime and phenolic resin, mix and stir for 10-15 minutes and then discharge.

[0074] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 850t. The resulting brick blanks have a bulk density of 3.10g / cm³. 3 ;

[0075] 4) Drying: Bake the brick blank at 180℃ for 24 hours to cure it. After naturally cooling to room temperature, take it out to obtain the brick.

[0076] In step 2), the mixing mill speed is 970 r / min.

[0077] Comparative Example 1

[0078] A method for preparing non-fired alumina-magnesia-carbon bricks, the specific steps of which are as follows:

[0079] 1) Ingredients: Accurately weigh 30 parts of high-alumina bauxite clinker, 5 parts of fused magnesia granules, 5 parts of fused magnesia fine powder, 4.5 parts of flake graphite, 5 parts of metallic aluminum powder, and 3 parts of phenolic resin.

[0080] 2) Mixing: Add high-alumina bauxite clinker, fused magnesia granules, fused magnesia fine powder, flake graphite, metallic aluminum powder and phenolic resin into a mixer, mix and stir for 20 minutes and then discharge.

[0081] 3) Molding: The mixed clay is pressed into brick blanks using a press with a pressure of 900t. The resulting brick blanks have a bulk density of 3.08g / cm³. 3 ;

[0082] 4) Drying: The brick blanks obtained in step 3) are baked and cured at 200℃ for 16 hours, and then naturally cooled to room temperature before being taken out to obtain bricks.

[0083] Among them, the particle size of the fused magnesia particles is 3-1mm, the particle size of the fused magnesia fine powder is 180-200 mesh, and the speed of the mixer in step (2) is 970r / min.

[0084] The apparent porosity, bulk density, room temperature compressive strength, and softening start temperature under 0.2 MPa load of the unburned alumina-magnesia-carbon bricks prepared in Examples 1, 2, 3, 4, 5, 6, and Comparative Example 1 were tested with reference to GB / T 2997-2015, GB / T 5072-2008, and GB / T 5989-2008.

[0085] Thermal shock stability test: The unburned alumina-magnesia-carbon bricks prepared in Examples 1, 2, 3, 4, 5, 6 and Comparative Example 1 were made into samples of 40mm×40mm×160mm. The samples were heated to 1100℃ and held for 30min. The samples were then removed and quickly placed in room temperature water for rapid cooling. The above process was repeated until the samples broke. The number of repetitions was recorded to evaluate the thermal shock stability of the samples.

[0086] The test data are shown in the table below:

[0087]

[0088]

[0089] Data from the unburned alumina-magnesia-carbon bricks prepared in Examples 1, 2, 3, 4, 5, 6, and Comparative Example 1 show that the unburned alumina-magnesia-carbon brick provided by this invention uses brown corundum with a specific particle size distribution, selects graphene oxide as the carbon source, and employs three additives: metallic aluminum powder, nano-sized vanadium pentoxide, and active lime. Finally, a specific preparation method is used, resulting in unburned alumina-magnesia-carbon bricks with low porosity, excellent erosion resistance, slag resistance, and good thermal shock stability. Using the unburned alumina-magnesia-carbon bricks provided by this invention as ladle linings can effectively reduce the content of carbon and sulfur impurities in molten steel, improving the quality of steel products. The preparation method of this invention uses readily available raw materials, has simple process steps, and does not require sophisticated production equipment, making it suitable for mass production.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A not-burned aluminum magnesium carbon brick, characterized by, The brown corundum, the fused magnesite, the graphene oxide, the metal aluminum powder, the nano vanadium pentoxide, the active lime and the phenolic resin are prepared from the following components by weight parts: 40-70 parts of brown corundum, 5-12 parts of fused magnesite, 4-7 parts of graphene oxide, 1-3 parts of metal aluminum powder, 0.5-2 parts of nano vanadium pentoxide, 0.5-1 part of active lime, and 2-4 parts of phenolic resin. The content of alumina in the brown corundum is not less than 95%, and the content of magnesia in the fused magnesite is not less than 97%.

2. The dead burned aluminum magnesia carbon brick according to claim 1, characterized in that, The brown corundum is composed of the following weight parts of brown corundum with different particle sizes: 20-40 parts of 5-3mm brown corundum, 10-15 parts of 3-1mm brown corundum, and 10-15 parts of brown corundum with a particle size of less than 200 mesh.

3. The unburned aluminum magnesium carbon brick according to claim 1 or 2, characterized in that, The particle size of the metal aluminum powder is less than 200 mesh, and the particle size of the active lime is less than 200 mesh.

4. The method of producing unburnt Al2O3-MgO-C brick according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: S1. batching: weighing each raw material component by weight parts; S2. mixing: preheating the brown corundum, the fused magnesite, the graphene oxide and the phenolic resin to 40-50℃, and then mixing each raw material in a mixer and discharging after mixing; S3. forming: adding the mud obtained after mixing to a steel mold to press and form a green brick; S4. drying: baking and curing the green brick obtained in step S3 at 180-220℃ for 18-24h to obtain the unburned aluminum-magnesia-carbon brick.

5. The method of producing dead burned aluminum magnesia carbon brick according to claim 4, characterized by, The brown corundum is composed of the following weight parts of brown corundum with different particle sizes: 20-40 parts of 5-3mm brown corundum, 10-15 parts of 3-1mm brown corundum, and 10-15 parts of brown corundum with a particle size of less than 200 mesh. During mixing, the brown corundum with a particle size of 5-3mm and 3-1mm and the fused magnesite are first added to the mixer and stirred for 3-5min to mix uniformly, and then the brown corundum with a particle size of 200 mesh, the graphene oxide, the metal aluminum powder, the nano vanadium pentoxide, the active lime and the phenolic resin are added, and mixed and stirred for 10-15min before discharging.

6. The method of producing unburned aluminum magnesium carbon brick according to claim 4 or 5, characterized by, The rotating speed of the mixer in step S2 is 970r / min.

7. The method of producing unburned aluminum magnesium carbon brick according to claim 4 or 5, characterized by, The pressure in the step S2 is 800-900 t, and the volume density of the green brick is 3.05-3.15 g / cm 3 .

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