Refractory brick for a steelmaking furnace lining and method for manufacturing the same

Abstract

The application provides a kind of firebrick for steelmaking furnace lining and a preparation method thereof, and the firebrick comprises the following components and the mass percentage of each component is as follows: 35-40% of macrocrystalline fused magnesia; 20-25% of coarse fused magnesia; 15-20% of fine fused magnesia; 4-8% of fused spinel; 4-8% of sintered spinel; 4-8% of bimodal alumina; 5-10% of AlSi12 alloy; 2-5% of Al-Mg alloy; and 2-5% of boron carbide, and the sum of the mass percentages of the components is 100%. The firebrick can be used in steel desulfurization smelting, is suitable for different desulfurization requirements and different smelting conditions, and has the advantages of long service life, good corrosion resistance and peeling resistance.

Description

Technical Field

[0001] This invention relates to the field of refractory brick technology, specifically to a refractory brick for steelmaking furnace lining and its preparation method. Background Technology

[0002] The sulfur content in steel products directly affects the corrosion resistance, fatigue characteristics, weldability, toughness, and plasticity of the structure. Therefore, it is necessary to control the sulfur content in the raw materials of steel products and remove it using steel refining desulfurization technologies such as RH, LF, and KR. A common desulfurization process uses lime powder as a desulfurizing agent, which can contact sulfur diffused to the surface, undergo a chemical reaction, and allow desulfurization products to diffuse at the reaction interface. The desulfurization reaction equation is: S + O₂ 2- =S 2- +O.

[0003] Alkaline oxides can provide oxygen ions to slag, so appropriately increasing the basicity of slag can promote the desulfurization reaction process. Moreover, the desulfurization reaction is an endothermic reaction at the slag-metal interface. To improve the desulfurization effect, it is necessary to increase the mass transfer coefficient and the reaction interface area. Therefore, strengthening stirring and increasing the reaction temperature are necessary parts of the desulfurization process.

[0004] The smelting process for high-quality, low-sulfur steel is mostly based on a CaO-CaF2 slag system, with the addition of appropriate amounts of Al2O3, MgO, and SiO2. The proportion of CaF2 is adjusted according to the sulfur content requirements of different steel grades. However, the addition of large amounts of CaO and CaF2 causes severe corrosion to the furnace lining refractory bricks, and the extremely high smelting temperatures place higher performance demands on the furnace lining materials. Furthermore, refractory bricks currently used in the smelting of low-sulfur steel generally suffer from short service life, poor erosion resistance, and poor spalling resistance, leading to increased maintenance costs and potential safety hazards. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a refractory brick for steelmaking furnace lining and its preparation method. This refractory brick can be used in steel desulfurization smelting, is suitable for different desulfurization requirements and different smelting conditions, and has the advantages of long service life, good erosion resistance, and good anti-spasting effect.

[0006] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides a refractory brick for steelmaking furnace lining, wherein the components and their mass percentages are as follows:

[0008] Large-crystal fused magnesia 35-40%;

[0009] 20-25% coarse dicalcium fused magnesia;

[0010] 15-20% fine dicalcium fused magnesia;

[0011] 4-8% fused spinel;

[0012] Sintered spinel 4-8%;

[0013] Bimodal alumina 4-8%;

[0014] 5-10% AlSi12 alloy;

[0015] 2-5% Al-Mg alloy;

[0016] Boron carbide 2-5%;

[0017] The sum of the mass percentages of all components is 100%.

[0018] Furthermore, the refractory bricks also contain a binder comprising 3-7% of the total mass of the refractory bricks, wherein the binder is any one of the following:

[0019] (a) Phenolic resin;

[0020] (ii) Phenolic resin and magnesium aluminum gel are mixed at a mass percentage of 1:0.43 to obtain the product;

[0021] (III) The magnesium-aluminum gel powder and deionized water are mixed at a mass ratio of 1:0.3 to obtain the product.

[0022] Among them, the phenolic resin used in (I) and (II) has a viscosity of 22000-24000 MPa·s and a residual carbon content of 6%; the magnesium aluminum gel used in (II) is made by mixing magnesium aluminum gel dry powder and water at a mass ratio of 1:0.18, and the particle size of the magnesium aluminum gel dry powder is less than 100 nm.

[0023] Furthermore, the particle size of the large-crystal fused magnesia is 4–1 mm;

[0024] The particle size of coarse dicalcium fused magnesia is 1-0 mm;

[0025] The particle size of fine dicalcium fused magnesia is 200 mesh;

[0026] 5μm fused spinel;

[0027] Sintered spinel 2-5μm;

[0028] Bimodal alumina 5μm;

[0029] AlSi12 alloy 10μm;

[0030] Al-Mg alloy 100μm;

[0031] Boron carbide, 350 mesh.

[0032] Furthermore, in the large-crystal fused magnesia, the content of periclase is >97%;

[0033] In dicalcium fused magnesia, the MgO content is 96-99%, and the ratio of impurity phase CaO to SiO2 is 2.

[0034] In fused spinel, the MgO content is >78%;

[0035] Bimodal alumina is an active alumina powder with a particle size distribution exhibiting a bimodal distribution;

[0036] In sintered spinel, the Al2O3 content is greater than 76%;

[0037] In Al-Mg alloys, the Al content is greater than 47%.

[0038] On the other hand, the present invention provides a method for preparing refractory bricks for steelmaking furnace linings, which mainly includes the following steps:

[0039] Step 1: Place the large-crystal fused magnesia, coarse dicalcium fused magnesia, fused spinel, sintered spinel, bimodal alumina, AlSi12 alloy and Al-Mg alloy into a mixer according to the mass percentage and stir evenly to obtain a granular mixture.

[0040] Fine dicalcium fused magnesia and boron carbide were placed in a mixer and stirred evenly to obtain a fine powder mixture;

[0041] Step 2: Add a binder to the granular mixture and knead until uniform. Then add the fine powder mixture and knead until uniform to obtain mud.

[0042] Step 3: Perform a binding process on the mud material;

[0043] Step 4: Place the mud in a mixer and mix it to obtain a mixture;

[0044] Step 5: The mixture is subjected to high-pressure molding at a pressure of 630T to 2500T to obtain brick blanks;

[0045] Step 6: Bake the brick blanks to obtain refractory bricks.

[0046] Furthermore, in step three, the material is kept in a state of stagnation for 3-4 days.

[0047] Furthermore, in step four, during the mixing and kneading process, 0-5% binder is added according to the bonding condition of the clay. The total amount of binder added in steps two and four accounts for 3-7% of the sum of the mass of the refractory bricks.

[0048] Furthermore, the binder is any one of the following:

[0049] (a) Phenolic resin;

[0050] (ii) Phenolic resin and magnesium aluminum gel are mixed at a mass percentage of 1:0.43 to obtain the product;

[0051] (III) The magnesium-aluminum gel powder and deionized water are mixed at a mass ratio of 1:0.3 to obtain the product.

[0052] The phenolic resin used in (i) and (ii) has a viscosity of 22000-24000 MPa·s and a residual carbon content of 6%.

[0053] (ii) The magnesium-aluminum gel used is made by mixing magnesium-aluminum gel powder and water at a mass ratio of 1:0.18, and the particle size of the magnesium-aluminum gel powder is less than 100nm.

[0054] Furthermore, the baking parameters differ depending on the binder added, including:

[0055] Case 1: When phenolic resin is used as the binder, the baking parameters are: 80-100℃ for 8 hours in air atmosphere, and 190-200℃ for 16 hours.

[0056] Scenario 2: When the binder is a mixture of phenolic resin and magnesium aluminum gel, the baking parameters are: 330-350℃ for 16 hours in air atmosphere.

[0057] Scenario 3: When the binder is a mixture of magnesium aluminum gel dry powder and deionized water, the baking parameters are: 100-110℃ for 24 hours in air atmosphere.

[0058] Furthermore, the refractory bricks obtained in step six are subjected to high-temperature firing in a nitrogen atmosphere. The firing temperature is 1600-1750℃, and the holding time is 1-3 hours.

[0059] Among them, large-crystal fused magnesia, coarse dicalcium fused magnesia, and fine dicalcium fused magnesia are used as aggregates, fused spinel, sintered spinel, and bimodal alumina are used as matrices, and AlSi12 alloy, Al-Mg alloy, and boron carbide are used as reaction precursors.

[0060] This invention selects large-crystal fused magnesia with a periclase content greater than 97% and good crystal development, and coarse dicalcium fused magnesia with an MgO content of 96-99% and an impurity phase CaO to SiO2 ratio of approximately 2 as aggregate. Due to the excellent high-temperature resistance of periclase, selecting large-crystal fused magnesia with good crystal development directly improves the high-temperature performance of the product. In this invention, the impurity composition of the coarse dicalcium fused magnesia selected has the following characteristics: when the calcium-silicon ratio is less than 1.87, the periclase bonding phase is low-melting-point calcium magnesium olivine or magnesium rhodochrosite; when it is greater than 1.87, the bonding phase is high-melting-point dicalcium silicate or tricalcium silicate. Strict control of the impurity content of the product helps to improve various properties of the product. Free calcium oxide and silicon dioxide, due to their low melting points, exist in liquid phase at high temperatures and can diffuse into the interior of the green body matrix, forming transgranular cracks inside the periclase, which are then dispersed and filled by the binder, greatly improving the high-temperature mechanical properties of the product. Selecting coarse dicalcium fused magnesia with a calcium-silicon ratio close to 2 can further improve the high-temperature performance of the product while ensuring the degree of periclase development.

[0061] In selecting matrix raw materials, this invention uses a compound of fine dicalcium fused magnesia, fused spinel, sintered spinel, and bimodal alumina, added in ultrafine powder form. The compound contains highly reactive periclase or corundum phases, which can undergo in-situ spinelization at high temperatures, promoting high-temperature sintering and improving product strength. The reason for choosing bimodal alumina is that its laser particle size distribution curve shows two peaks, compared to single-peak alumina with only one peak and a more concentrated particle size. Bimodal alumina has a wider and more uniform particle size distribution, better satisfying the principle of closest packing and improving product densification. Furthermore, bimodal alumina has higher reactivity, participating in the reaction to generate the spinel phase under medium-temperature conditions, promoting product sintering.

[0062] This invention selects AlSi12 alloy with 11% Si content, Al-Mg alloy with 47% Al content, and boron carbide as reaction precursors. Among them, AlSi12 alloy improves the product's resistance to molten steel erosion and extends its service life; magnesium-aluminum alloy can participate in the formation of intermediate products in the MgAlON structural reaction; boron carbide, as a carbide, has a large wetting angle and poor wettability with oxide slag, which can improve the product's resistance to slag erosion. The combination of these three materials has the following advantages: (1) During high-temperature firing in a nitrogen atmosphere with low oxygen partial pressure, as the temperature rises, metallic Al can react to generate AlN and Al2O, and metallic Mg, after vaporization, participates in the formation of the MgAlON phase in the matrix, which greatly improves the erosion resistance and thermal stability of the refractory bricks, thereby extending their service life; (2) This invention selects AlSi12 alloy and Al-Mg alloy instead of directly using elemental magnesium and aluminum. This is because elemental aluminum and magnesium are highly reactive, and a dense oxide film is easily formed on their surface under normal temperature conditions, which is not conducive to the subsequent formation of aluminum nitride or aluminum carbide, and is not conducive to the subsequent reaction or the formation of the MgAlON structure. The alloy has a high reaction initiation temperature, which is more conducive to the formation of the MgAlON structure.

[0063] The binder is any one of the following: phenolic resin, a mixture of phenolic resin and magnesium aluminum gel at a mass percentage of 1:0.43, or a mixture of magnesium aluminum gel powder and deionized water at a mass percentage of 1:0.3. The phenolic resin has a viscosity of 22000-24000 MPa·s and a residual carbon content of 6%. Using a high-viscosity phenolic resin (viscosity 22000-24000 MPa·s) with a residual carbon content of approximately 6% as the binder improves the product's room-temperature performance and prevents it from participating in matrix reactions under service conditions. Nanoscale magnesium aluminum gel powder is selected, utilizing its nano-effect and ultra-high reactivity to promote product sintering.

[0064] The high-temperature firing of the bricks is carried out under a nitrogen atmosphere. Under the nitrogen-dominated reducing atmosphere, the metallic aluminum in the brick matrix is ​​nitrided to form AlN, and due to the low oxygen partial pressure, it is partially and incompletely oxidized to form Al2O. The overall reaction equation is as follows:

[0065] AlN(g)+3Al2O(g)+7Mg(g)+3N2(g)+2O2(g)→7MgAlON(s)

[0066] AlON(g) + Mg(g) → MgAlON(s)

[0067] The MgAlON structure is woven in a crisscross pattern within the cavities of the refractory brick, forming a dense, erosion-resistant layer that significantly improves product performance.

[0068] Beneficial effects:

[0069] 1) The specific supply form of the refractory bricks of this invention is determined according to the actual working conditions. They can be supplied as unfired bricks (only requiring baking) or as fired bricks (fired bricks) produced by high-temperature firing under a nitrogen atmosphere. Specifically, unfired bricks are supplied when the on-site working conditions are rough vacuum (<53 Pa) and the smelting temperature is above 1700℃; otherwise, fired bricks are required. The ultimate goal is to create an environment more suitable for the development of the MgAlON structure. Determining whether to supply fired or unfired bricks based on actual working conditions reduces product energy consumption to some extent and meets the concept of green and sustainable development.

[0070] 2) The fired bricks of the present invention are fired at high temperature under nitrogen protection. The refractory bricks with MgAlON structure have higher high temperature resistance and stability, and can adapt to a wider range of smelting process requirements.

[0071] 3) When the binder of the refractory bricks in this invention is a mixture of phenolic resin and magnesium aluminum gel, a smoke-generating and environmentally friendly baking process can be adopted to meet the concept of green and sustainable development.

[0072] 4) The refractory bricks of this invention can effectively improve the production efficiency and quality of steel smelting, making steel smelting more environmentally friendly, energy-saving, safe, and sustainable. Compared with existing technologies, this new type of refractory brick has higher performance and a wider range of applications. At the same time, its preparation process is more optimized, effectively improving production efficiency and quality while reducing production costs, demonstrating significant advantages. Attached Figure Description

[0073] Figure 1 The image shows the microstructure of the unfired bricks prepared in Example 1 after their use in a steelmaking furnace. Detailed Implementation

[0074] The technical solution of the present invention will be clearly and completely described below with reference to specific 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 protection scope of the present invention.

[0075] Example 1

[0076] For the RH slag system of a certain steel plant, the amount of electrofused spinel added is adjusted.

[0077] In order to prepare refractory bricks with good refractory properties, the preparation method of refractory bricks in this embodiment is as follows:

[0078] Step 1: Raw material processing: Weigh the raw materials according to the mass percentage in Table 1. Place the large crystal fused magnesia, coarse dicalcium fused magnesia, fused spinel, sintered spinel, bimodal alumina, AlSi12 alloy and Al-Mg alloy into a mixer according to the mass percentage and stir evenly to obtain a granular mixture.

[0079] Fine dicalcium fused magnesia and boron carbide were placed in a mixer and stirred evenly to obtain a fine powder mixture;

[0080] Step 2: Add a binder to the granular mixture and knead until uniform. Then add the fine powder mixture and knead until uniform to obtain mud.

[0081] Step 3: Allow the mud to rest for 3-4 days;

[0082] Step 4: Place the mud in a mixer, add a binder depending on the binding condition of the mud, and mix and knead to obtain a mixture;

[0083] Step 5: The mixture is subjected to high-pressure molding under a pressure of 1000T to obtain brick blanks;

[0084] Step 6: Place the brick blanks in a drying oven for baking. First, keep them at 100℃ for 8 hours, and then keep them at 200℃ for 16 hours to fully dry the refractory brick blanks, thereby improving their room temperature strength and resistance to slag erosion, thus obtaining unfired bricks.

[0085] Table 1. Raw materials used in Example 1

[0086]

[0087] Figure 1 The image shows the microstructure of the unburned bricks prepared in this embodiment after use in a steelmaking furnace. As can be seen from the image, there are many lamellar MgAlON structures distributed in a crisscross pattern inside the brick (as indicated by the arrows), which can improve the erosion resistance of the refractory bricks.

[0088] The refractory bricks obtained in this embodiment have a room temperature compressive strength of 120 MPa and a bulk density of 3.15 g / cm³. 3 The prepared refractory bricks are applied to the industrial production of high-quality, low-sulfur steel. This product has been used in the RH furnace of the steel plant. The maximum number of times the lower trough furnace is used is 476 times per day, and the maximum number of times the circulating tube impregnation tube is used is 147 times per day.

[0089] Example 2

[0090] For the LF slag system of a certain steel plant, magnesium aluminum gel was selected as a binder to control the firing atmosphere and temperature.

[0091] In order to prepare refractory bricks with good refractory properties, the following method is used in this embodiment:

[0092] Step 1: Raw material processing: Weigh the raw materials according to the mass percentage in Table 2. Place the large crystal fused magnesia, coarse dicalcium fused magnesia, fused spinel, sintered spinel, bimodal alumina, AlSi12 alloy and Al-Mg alloy into a mixer according to the mass percentage and stir evenly to obtain a granular mixture.

[0093] Fine dicalcium fused magnesia and boron carbide were placed in a mixer and stirred evenly to obtain a fine powder mixture;

[0094] Step 2: Add a binder to the granular mixture and knead until uniform. Then add the fine powder mixture and knead until uniform to obtain mud.

[0095] Step 3: Allow the mud to rest for 3-4 days;

[0096] Step 4: Place the mud in a mixer, add a binder depending on the binding condition of the mud, and mix and knead to obtain a mixture;

[0097] Step 5: The mixture is subjected to high-pressure molding at 2000T to obtain brick blanks;

[0098] Step 6: Place the brick blanks in a drying oven for baking, and keep them at 110℃ for 24 hours to ensure that the refractory brick blanks are fully dried.

[0099] Step 7: Place the completely dried refractory bricks into a sagger and fire them under a nitrogen protective atmosphere at a maximum firing temperature of 1700℃ for 2 hours to promote the formation of MgAlON structures in the green body matrix, thus obtaining the fired bricks.

[0100] Table 2. Raw materials used in Example 2

[0101]

[0102]

[0103] The refractory bricks obtained in this embodiment have a strength of 130 MPa and a bulk density of 3.12 g / cm³. 3 The prepared refractory bricks are applied to the industrial production of high-quality, low-sulfur steel. This product has been used in the LF furnace of the steel plant, and customer feedback indicates high satisfaction.

[0104] Example 3

[0105] For the LF slag system of a certain steel plant, phenolic resin + magnesium aluminum gel was selected as the binder, and the drying process was adjusted.

[0106] In order to prepare refractory bricks with good refractory properties, the following method is used in this embodiment:

[0107] Step 1: Raw material processing: Weigh the raw materials according to the mass percentage in Table 3. Place the large crystal fused magnesia, coarse dicalcium fused magnesia, fused spinel, sintered spinel, bimodal alumina, AlSi12 alloy and Al-Mg alloy into a mixer according to the mass percentage and stir evenly to obtain a granular mixture.

[0108] Fine dicalcium fused magnesia and boron carbide were placed in a mixer and stirred evenly to obtain a fine powder mixture;

[0109] Step 2: Add a binder to the granular mixture and knead until uniform. Then add the fine powder mixture and knead until uniform to obtain mud.

[0110] Step 3: Allow the mud to rest for 3-4 days;

[0111] Step 4: Place the mud in a mixer, add a binder according to the binding condition of the mud, and mix and knead to obtain a mixture;

[0112] Step 5: The mixture is subjected to high-pressure molding at 2500T to obtain brick blanks;

[0113] Step 6: Place the brick blanks in a drying oven for baking. Keep them at 350℃ for 16 hours to fully dry the refractory brick blanks, thereby improving their room temperature strength and resistance to slag erosion, thus obtaining unfired bricks.

[0114] Table 3. Raw materials used in Example 3

[0115]

[0116]

[0117] The refractory bricks obtained in this embodiment have a strength of 150 MPa and a bulk density of 3.15 g / cm³. 3 The prepared refractory bricks are applied to the industrial production of high-quality, low-sulfur steel. This product has been used in the LF furnace of a steel plant, and the customer has reported that the on-site environment has been improved.

[0118] It should be noted that during the preparation of refractory bricks in Examples 1-3, an appropriate amount of binder can be added during the mixing process in step four, depending on the state of the clay, to improve the molding performance of the clay. However, the total amount of binder added in steps two and four should be 3-7% of the mass of the refractory bricks.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention in any way. All equivalent transformations or modifications made in accordance with the essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A refractory brick for steelmaking furnace lining, characterized in that, The components and their mass percentages are as follows: Large-crystal fused magnesia 35-40%; 20-25% coarse dicalcium fused magnesia; Fine dicalcium fused magnesia 15-20%; 4-8% fused spinel; Sintered spinel 4-8%; Bimodal alumina 4~8%; AlSi12 alloy 5~10%; Al-Mg alloy 2~5%; Boron carbide 2~5%; The sum of the mass percentages of all components is 100%. The refractory bricks also contain a binder comprising 3-7% of the total mass of the refractory bricks, wherein the binder is any one of the following: (a) Phenolic resin; (ii) Phenolic resin and magnesium aluminum gel are mixed at a mass ratio of 1:0.43 to obtain the product; (iii) The magnesium-aluminum gel powder and deionized water are mixed at a mass ratio of 1:0.3 to obtain the product; The phenolic resin used in (i) and (ii) has a viscosity of 22000-24000 MPa·s and a residual carbon content of 6%. (ii) The magnesium-aluminum gel used is made by mixing magnesium-aluminum gel powder and water at a mass ratio of 1:0.18, and the particle size of the magnesium-aluminum gel powder is less than 100nm.

2. The refractory brick for steelmaking furnace lining according to claim 1, characterized in that, The particle size of large-crystal fused magnesia is 4~1mm; The particle size of coarse dicalcium fused magnesia is 1-0 mm; The particle size of fine dicalcium fused magnesia is 200 mesh; 5μm fused spinel; Sintered spinel 2-5μm; Bimodal alumina 5μm; AlSi12 alloy 10μm; Al-Mg alloy 100μm; Boron carbide, 350 mesh.

3. The refractory brick for steelmaking furnace lining according to claim 1, characterized in that, In large-crystal fused magnesia, the content of periclase is >97%; In dicalcium fused magnesia, the MgO content is 96-99%, and the ratio of impurity phase CaO to SiO2 is 2. In fused spinel, the MgO content is >78%; Bimodal alumina is an active alumina powder with a particle size distribution exhibiting a bimodal distribution; In sintered spinel, the Al2O3 content is greater than 76%; In Al-Mg alloys, the Al content is greater than 47%.

4. A method for preparing refractory bricks for steelmaking furnace linings as described in any one of claims 1-3, characterized in that, The main steps include the following: Step 1: Place the large-crystal fused magnesia, coarse dicalcium fused magnesia, fused spinel, sintered spinel, bimodal alumina, AlSi12 alloy and Al-Mg alloy into a mixer according to the mass percentage and stir evenly to obtain a granular mixture. Fine dicalcium fused magnesia and boron carbide were placed in a mixer and stirred evenly to obtain a fine powder mixture; Step 2: Add a binder to the granular mixture and knead until uniform. Then add the fine powder mixture and knead until uniform to obtain mud. Step 3: Perform a binding process on the mud material; Step 4: Place the mud in a mixer and mix it to obtain a mixture; Step 5: The mixture is subjected to high-pressure molding at a pressure of 630T~2500T to obtain brick blanks; Step 6: Bake the brick blanks to obtain refractory bricks.

5. The method for preparing refractory bricks for steelmaking furnace lining according to claim 4, characterized in that, In step three, the material is kept in a state of stagnation for 3-4 days.

6. The method for preparing refractory bricks for steelmaking furnace lining according to claim 4, characterized in that, In step four, during the mixing and kneading process, 0-5% binder is added according to the bonding condition of the clay. The total amount of binder added in steps two and four accounts for 3-7% of the total mass of the refractory bricks.

7. The method for preparing refractory bricks for steelmaking furnace lining according to claim 6, characterized in that, The binder is any one of the following: (a) Phenolic resin; (ii) Phenolic resin and magnesium aluminum gel are mixed at a mass ratio of 1:0.43 to obtain the product; (iii) The magnesium-aluminum gel powder and deionized water are mixed at a mass ratio of 1:0.3 to obtain the product; The phenolic resin used in (i) and (ii) has a viscosity of 22000-24000 MPa·s and a residual carbon content of 6%. (ii) The magnesium-aluminum gel used is made by mixing magnesium-aluminum gel powder and water at a mass ratio of 1:0.18, and the particle size of the magnesium-aluminum gel powder is less than 100nm.

8. The method for preparing refractory bricks for steelmaking furnace lining according to claim 7, characterized in that, Different binders require different baking parameters, including: Case 1: When phenolic resin is used as the binder, the baking parameters are: 80-100℃ for 8 hours in air atmosphere, and 190-200℃ for 16 hours. Scenario 2: When the binder is a mixture of phenolic resin and magnesium aluminum gel, the baking parameters are: 330-350℃ for 16 hours in air atmosphere. Scenario 3: When the binder is a mixture of magnesium aluminum gel dry powder and deionized water, the baking parameters are: 100-110℃ for 24 hours in air atmosphere.

9. The method for preparing refractory bricks for steelmaking furnace lining according to claim 4, characterized in that, The refractory bricks obtained in step six are subjected to high-temperature firing in a nitrogen atmosphere. The firing temperature is 1600-1750℃, and the holding time is 1-3 hours.

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