Al-al2o3 slide plate brick with titanium concentrate added and production method thereof

Abstract

The application relates to a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate and a production method thereof, raw materials being as follows: 46-62% tabular corundum, 10-20% fused dense corundum, 6-10% active alumina micropowder, 5-8% silicon carbide micropowder, 7-10% titanium concentrate, 4-8% metal aluminum powder and 1-3% boron glass powder, plus 3-4% phenolic resin and 1-2% boron-modified phenolic resin powder of the total weight of the above raw materials. The product has an apparent porosity of 5-8%, a bulk density of 3.10-3.20 g / cm 3 , a normal-temperature compressive strength of 160-260 MPa, a normal-temperature bending strength of 25-36 MPa and a high-temperature bending strength of 25-35 MPa; the product has good compactness and strength. The slide plate brick of the application has low carbon content, only contains combined carbon SiC and residual carbon of the resin, and does not need to be impregnated with pitch and dry distillation after sintering, so that the environmental pollution caused by pitch volatilization in the production and use processes is avoided.

Description

TECHNICAL FIELD

[0001] The application relates to a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate and a production method thereof, and belongs to the technical field of functional refractory materials. BACKGROUND

[0002] A slide gate is a device for controlling the flow of molten steel in the steel smelting process, has good controllability, and can improve the steelmaking production efficiency. With the development of rapid and efficient continuous casting and secondary refining technology and process, the slide gate system becomes more and more important in the modern steel smelting process and becomes an indispensable part in smelting. The slide plate brick is a key component of the slide gate, directly controls the flow of molten steel, and determines the function of the slide gate. In the service process, the working temperature difference between the closing and opening of the slide plate is extremely large, so the high-temperature strength, thermal shock resistance and erosion resistance of the refractory material are extremely high.

[0003] Traditional slide plate bricks are usually carbon-containing refractory materials. Different metal raw materials are used for slide plate bricks prepared by different processes. The unburned slide plate brick uses metal aluminum as the main raw material, and the high-temperature sintered slide plate brick uses metal silicon as the main raw material. With the requirement of low carbonization of carbon-containing refractory materials, a slide plate material with unique microstructure and performance is prepared by adopting multi-metal composite addition, an in-situ reaction mechanism based on temperature gradient is formed, a non-metallic reinforcing phase is generated, the high-temperature strength and thermal shock resistance of the material are improved, the carbon content of the slide plate material is reduced, and a low-carbon slide plate brick with excellent performance is developed.

[0004] The low carbonization of the carbon-containing material system of the slide plate brick is the requirement of special steel smelting. Due to the role of carbon in the material system, the reduction of the carbon content will cause the performance of the slide plate brick to decrease, and the non-oxide material has excellent performance and is an ideal substitute for carbon. The abundance of titanium ranks fourth among metals, only next to iron, aluminum and magnesium. The non-oxide TiN, TiC and Ti(C, N) of titanium have excellent performance and can replace carbon sources to significantly improve the comprehensive performance of the slide plate brick. However, the raw material is expensive and the cost is high. The in-situ synthesis technology is adopted to generate the non-oxide reinforcing phase of titanium in the material in-situ, which is an effective way to prepare a low-cost high-performance low-carbon slide plate brick product.

[0005] The patent application with the title of a slide plate brick added with composite alumina powder and carbon source and a preparation method thereof and the publication number CN108484138A adopts high-temperature sintering and dry distillation impregnation processes, adds the composite alumina powder and the carbon source, changes the adjustment of the alumina powder, thereby improving the thermal shock resistance, erosion resistance and corrosion resistance of the slide plate brick, and prolonging the service life. However, the carbon content is high, and the dry distillation impregnation process is not conducive to environmental protection. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a high-temperature sintered Al-Al2O3 slide plate brick with titanium concentrate and a production method thereof.The method of high-temperature sintering oil-impregnated low-carbon slide plate brick overcomes the dependence of traditional slide plate bricks on carbon and solves the adverse effects of the reduction of carbon content in carbon-containing refractory materials on their thermal shock resistance and high-temperature resistance.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0008] A high-temperature sintered Al-Al2O3 slide plate brick with titanium concentrate, the raw material composition is: 46-62% tabular corundum, 10-20% fused dense corundum, 6-10% active alumina powder, 5-8% silicon carbide powder, 7-10% titanium concentrate, 4-8% aluminum powder, 1-3% boron glass powder, plus 3-4% phenolic resin, 1%-2% boron modified phenolic resin powder of the total weight of the above-mentioned raw materials.

[0009] The tabular corundum includes three kinds of granules: 1mm < particle size 1 ≤ 2mm, 0.6mm < particle size 2 ≤ 1mm, 0.2mm < particle size 3 ≤ 0.6mm, and the weight ratio of different particle sizes is: particle size 1: particle size 2: particle size 3 = 20:20:6-22.

[0010] The particle size of the fused dense corundum is: 0.044mm < particle size 4 ≤ 0.2mm, particle size 5 ≤ 0.044mm, and the weight ratio of different particle sizes is: particle size 4: particle size 5 = 5-20:0-5.

[0011] The active alumina powder is CL370 and RG4000 produced by Anmai Aluminum Industry (Qingdao) Co., Ltd., and the weight ratio of the two is 1:1.

[0012] The SiC content in the silicon carbide powder is ≥98%, D 50 ≈2.0μm.

[0013] The particle size of the titanium concentrate is ≤0.074mm, and the main components are: TiO2 ≥40%, Fe2O3 ≥30%, CaO ≤1.5%, MgO ≤2%, Al2O3 ≤2%, and MnO ≤1%.

[0014] The particle size of the aluminum powder is ≤0.044mm.

[0015] The particle size of the boron glass powder is ≤0.044mm, the B2O3 content is ≥14%, and the melting point is 400-800℃.

[0016] The type of the phenolic resin is PF5323, the decomposition temperature of the boron modified phenolic resin powder is ≥500℃, and the carbon residue rate at 1000℃ is ≥50%.

[0017] The preparation method of the slide plate brick comprises the following steps:

[0018] (1) proportionally weigh each raw material and prepare;

[0019] (2) first, the raw material ≤0.6mm and the boron modified phenolic resin powder are added into the conical mixer in the order of light first and heavy later, and mixed for 20-30min to obtain the premixed powder;

[0020] (3) then, the particle material greater than 0.6mm in the raw material is added into the wheel mill and stirred for 3-5min, the phenolic resin is added and stirred for 5-8min, after the particles are completely wetted, the premixed powder is added, and the mixing is continued for 30-40min to obtain the mixed mud;

[0021] (4) the mud is stored for 8-24 hours under the conditions of temperature 25-35℃ and humidity 40-50%, and then is pressed to form a slide plate brick body;

[0022] (5) after the body is naturally dried for 24h, the body is dried in a dryer, the heating rate is 10-15℃ / h, the drying temperature is 230-280℃, and after the temperature reaches the drying temperature, the temperature is kept for 8-10h;

[0023] (6) the dried body is fired in a nitriding furnace under the nitrogen atmosphere, the firing temperature is 1200-1400℃, and the holding time is 8-12h;

[0024] (7) after the body is fired, the body is subjected to the hoop adding, grinding and coating processes to obtain the target product.

[0025] The present application has the following beneficial effects:

[0026] (1) the present application is a low-carbon slide plate brick fired at high temperature, the carbon content is relatively low, only the combined carbon SiC and the residual carbon of the resin are contained in the product, and after the product is fired, it is not necessary to be impregnated with pitch and dry distillation, so that the pollution of pitch volatilization to the environment in the production and use processes is avoided, and the present application is a low-carbon and green preparation technology of the slide plate brick.

[0027] (2) the electrically fused dense corundum in the present application is introduced in the form of particles less than 0.2mm and fine powder, the dense corundum has the characteristics of high bulk density and good crystallization, so that the bulk density and the corrosion resistance of the product are improved, and two kinds of active alumina powder are introduced to adjust the reaction activity of the product at high temperature, and the micropowder is better filled in the pores to improve the density and the strength of the product.

[0028] (3) Using titanium concentrate as raw material, while introducing metal aluminum powder, in the process of high temperature heat treatment in nitrogen atmosphere, titanium concentrate and part of metal aluminum occur aluminothermic reduction reaction, in-situ generating titanium-iron alloy, aluminum oxide and titanium trioxide, etc. The titanium-iron alloy generated by the reaction has a high melting point and is uniformly distributed in the system, replacing metal aluminum as a high-temperature plastic phase to improve the high-temperature performance of the product. At the same time, the titanium trioxide generated by the aluminothermic reaction further reacts with the residual carbon in the resin to generate a non-oxide titanium carbide reinforcing phase, improving the performance of the slide plate. Compared with directly introducing titanium-iron alloy and titanium trioxide, the cost of introducing titanium concentrate is significantly reduced (see Figure 1 ).

[0029] (4) Using metal aluminum as the metal raw material, on the one hand, the aluminothermic reduction reaction occurs between metal aluminum and titanium concentrate, and on the other hand, at high temperature, metal aluminum reacts with nitrogen, residual carbon in the resin and silicon carbide powder to generate non-oxide reinforcing phases such as AlN-SiC solid solution, etc. At the same time, the transformation of metal aluminum into easily hydrated products such as aluminum carbide and aluminum nitride is avoided, improving the anti-hydration performance of the product (see Figure 2 ).

[0030] (5) Using silicon carbide powder can improve the thermal shock stability of the product. At the same time, the silicon carbide powder has high activity and generates active oxidation reaction in the high-temperature sintering process, generating gaseous SiO, which reacts with metal aluminum, residual carbon in the resin, etc. to generate Al4SiC4 non-oxide reinforcing phase, which can improve the performance of the product (see Figure 3 ).

[0031] (6) Compound use of boron glass powder and boron modified phenolic resin as antioxidant can prevent the oxidation of residual carbon in the resin and silicon carbide. On the other hand, boron glass powder generates liquid phase at high temperature, promoting sintering and improving product strength. At the same time, it can block the pores and hinder the entry of external oxygen into the interior of the sample. In addition, boron reacts with oxygen preferentially, significantly reducing the oxygen partial pressure in the interior of the sample, promoting the occurrence of active oxidation reaction of silicon carbide powder, and improving the performance of the product.

[0032] (7) The slide plate brick of the present application has the advantages of high strength, good thermal shock stability, strong adaptability to steel grades, long service life, etc. The specific performance indicators are: apparent porosity 5-8%, bulk density 3.10-3.20 g / cm 3 , cold crushing strength 160-260 MPa, cold modulus of rupture 25-36 MPa, and high-temperature modulus of rupture (1400℃×0.5h, buried carbon) 25-35 MPa. The product has good density and strength.

[0033] The performance indicators of the present application meet the requirements of the HBLT-80 grade (non-impregnated) indicators in the YB / T 5049-2019 “Slide Plate Brick” industry standard: apparent porosity ≤13%, bulk density ≥2.90 g / cm 3Compared with the normal temperature pressure strength ≥ 80MPa, it has significant advantages. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 One of SEM images of the product of the present application;

[0035] Figure 2 Two of SEM images of the product of the present application,

[0036] Figure 2 In the figure, the right is a local enlarged view of the left;

[0037] Figure 3 Three of SEM images of the product of the present application. DETAILED DESCRIPTION

[0038] The specific embodiments of the present application are further described in detail below in conjunction with examples.

[0039] Example 1

[0040] An Al-Al2O3 slide plate brick added with titanium concentrate, the raw material composition is as follows in percentage by weight: 62% tabular corundum, 10% fused dense corundum, 6% active alumina powder, 8% silicon carbide powder, 7% titanium concentrate, 4% metal aluminum powder, 3% boron glass powder, plus 3% PF5323 phenolic resin, 2% boron modified phenolic resin powder binder in total weight of the above raw materials.

[0041] Tabular corundum: including three kinds of 1mm < particle size 1 ≤ 2mm, 0.6mm < particle size 2 ≤ 1mm, 0.2mm < particle size 3 ≤ 0.6mm; different particle size weight ratio: particle size 1: particle size 2: particle size 3 = 20:20:22.

[0042] Fused dense corundum particle size: 0.044mm < particle size 4 ≤ 0.2mm, particle size 5 ≤ 0.044mm; two kinds of particle size are mixed in equal proportion.

[0043] Active alumina powder is CL370 and RG4000 produced by Anmai Aluminum Industry (Qingdao) Co., Ltd., wherein CL370: Al2O3 ≥ 99.5%, specific surface area ≈ 7.2m 2 / g, D 50 ≈0.6μm, RG4000: Al2O3 ≥ 99.5%, specific surface area ≈ 3.0m 2 / g, D 50 ≈2.5μm, both are mixed in equal proportion.

[0044] The SiC content in silicon carbide powder is ≥ 98%, particle size D 50 ≈2.0μm.

[0045] Titanium concentrate particle size ≤0.074mm, its main components are: TiO2≥40%, Fe2O3≥30%, CaO≤1.5%, MgO≤2%, Al2O3≤2%, MnO≤1%.

[0046] Metallic aluminum powder particle size ≤0.044mm.

[0047] Boron glass powder particle size ≤0.044mm, B2O3 content ≥14%, melting point 400-800℃.

[0048] Phenolic resin: model PF5323, viscosity / 25℃ 16000-19000mPa·s, solid content 78-83%, carbon residue at 800℃ 43-47%, moisture 2-3%, produced by Shandong Shengquan New Material Co., Ltd.

[0049] Boron-modified phenolic resin powder: decomposition temperature ≥500℃, carbon residue rate at 1000℃ ≥50%, free phenol ≤7%.

[0050] The production method of the Al-Al2O3 slide plate brick comprises the following steps:

[0051] (1) weigh each raw material according to the proportion, and prepare for use;

[0052] (2) first, the materials ≤0.6mm in the raw materials and the boron-modified phenolic resin powder are added into the conical mixer in the order of light first and heavy last, and mixed for 20-30min to obtain a premixed powder;

[0053] (3) the granular material greater than 0.6mm in the raw materials is added into the wheel mill and stirred for 3-5min, then the phenolic resin is added and stirred for 5-8min, after the granular material is completely wetted, the premixed powder is added, and the mixing is continued for 30-40min to obtain the mixed mud;

[0054] (4) the mud is stored for 16-24 hours under the conditions of temperature 25-35℃ and humidity 40-50%, and then is pressed into a green body of the slide plate brick;

[0055] (5) after the green body is naturally dried for 24h, it is dried in a dryer, the heating rate is 10-15℃ / h, the drying temperature is 230-280℃, and after the temperature reaches the drying temperature, it is kept for 8-10h;

[0056] (6) the dried green body is fired in a nitrogen atmosphere in a nitriding furnace, the firing temperature is 1300℃, and the holding time is 12h;

[0057] (7) the fired green body is subjected to the processes of hoop adding, grinding, coating, etc. to obtain the target product.

[0058] The scanning electron microscope analysis of the product of the example shows that the non-oxide reinforcing phase in-situ generated in different areas of the sample has a typical structure as shown in Figures 1-3 .

[0059] As can be seen from Figure 1 , the polyhedral and granular titanium carbide reinforcing phase is generated by the reaction of the di-titanium trioxide and the carbon residue of the resin, and the titanium carbide has excellent properties such as high melting point, good chemical stability and good oxidation resistance, and can improve the comprehensive performance of the product.

[0060] As can be seen from Figure 2 , the AlN-SiC solid solution reinforcing phase is in-situ generated in the product, and the solid solution is in the form of granules, and there are needle-like structures around the granules, which form a "pinned" structure in the matrix and can improve the strength of the product.

[0061] As can be seen from Figure 3 , the flaky Al4SiC4 is generated by the reaction of SiO, metallic aluminum and carbon residue of the resin, and the flaky structure can improve the bonding strength between the matrix and the granules, and has a flaky toughening effect, and at the same time, the flaky Al4SiC4 is in-situ generated at the pores, which can fill the pores, improve the strength and bulk density of the product, and reduce the apparent porosity.

[0062] The SEM images of the products of other examples are similar to this.

[0063] The performance indicators of the obtained product are as follows: apparent porosity 8%, bulk density 3.10 g / cm 3 , cold crushing strength 160 MPa, cold modulus of rupture 25 MPa, and high-temperature modulus of rupture (1400℃×0.5h, buried carbon) 25 MPa.

[0064] Example 2

[0065] An Al-Al2O3 slide plate brick with titanium concentrate added, the raw material composition is as follows in terms of weight percentage: 55% tabular corundum, 15% fused dense corundum, 8% active alumina powder, 6% silicon carbide powder, 8% titanium concentrate, 6% metallic aluminum powder, 2% boron glass powder, plus 3.5% PF5323 phenolic resin and 1.5% boron-modified phenolic resin powder binders of the total weight of the above raw materials.

[0066] The tabular corundum includes three kinds of 1mm<particle size 1≤2mm, 0.6mm<particle size 2≤1mm, 0.2mm<particle size 3≤0.6mm, and the weight ratio is: particle size 1: particle size 2: particle size 3 = 20:20:15.

[0067] The particle size of the fused dense corundum is: 0.044mm<particle size 4≤0.2mm, particle size 5≤0.044mm; and the weight ratio is: particle size 4: particle size 5 = 10:5.

[0068] The performance requirements and production method of other raw material components are the same as those of Example 1.

[0069] The performance indexes of the obtained product are: apparent porosity 6.8%, bulk density 3.16 g / cm 3 , cold crushing strength 234 MPa, cold modulus of rupture 31 MPa, and hot modulus of rupture (1400℃×0.5h, carbon embedded) 29 MPa.

[0070] Example 3

[0071] An Al-Al2O3 slide plate brick with titanium concentrate added, the raw material components are as follows in percentage by weight: 46% tabular corundum, 20% fused dense corundum, 10% active alumina micropowder, 5% silicon carbide micropowder, 10% titanium concentrate, 8% metallic aluminum powder, and 1% boron glass powder, plus 4% PF5323 phenolic resin and 1% boron modified phenolic resin powder of the total weight of the above raw materials.

[0072] The tabular corundum includes three kinds of: 1mm<particle size 1≤2mm, 0.6mm<particle size 2≤1mm, and 0.2mm<particle size 3≤0.6mm; the weight ratio of different particle sizes is: particle size 1: particle size 2: particle size 3=20:20:6.

[0073] The particle size of the fused dense corundum is: 0.044mm<particle size 4≤0.2mm.

[0074] The performance requirements and production method of other raw material components are the same as those of Example 1.

[0075] The performance indexes of the obtained product are: apparent porosity 5%, bulk density 3.20 g / cm 3 , cold crushing strength 260 MPa, cold modulus of rupture 36 MPa, and hot modulus of rupture (1400℃×0.5h, carbon embedded) 35 MPa.

Claims

1. A method for producing a high-temperature sintered Al-Al2O3 slide plate brick to which a titanium concentrate is added, characterized by, The raw material composition by weight percentage is: 46-62% tabular corundum, 10-20% fused dense corundum, 6-10% active alumina powder, 5-8% silicon carbide powder, 7-10% titanium concentrate, 4-8% metal aluminum powder, 1-3% boron glass powder, plus 3-4% phenolic resin, 1%-2% boron modified phenolic resin powder of the total weight of the above raw materials; The tabular corundum includes three kinds of granules: 1mm < particle size 1 ≤ 2mm, 0.6mm < particle size 2 ≤ 1mm, 0.2mm < particle size 3 ≤ 0.6mm, and the weight ratio of different particle sizes is particle size 1: particle size 2: particle size 3 = 20:20:6-22; The fused dense corundum particle size is: 0.044mm < particle size 4 ≤ 0.2mm, particle size 5 ≤ 0.044mm, and the weight ratio of different particle sizes is: particle size 4: particle size 5 = 5-20:0-5; The active alumina powder is CL370 and RG4000 produced by Anmai Aluminum Industry (Qingdao) Co., Ltd., and the weight ratio of the two is 1:1; The titanium concentrate particle size is ≤0.074mm, and the main components are: TiO2 ≥40%, Fe2O3 ≥30%, CaO ≤1.5%, MgO ≤2%, Al2O3 ≤2%, MnO ≤1%; The specific steps of the preparation method are: (1) weigh the raw materials according to the proportion, and reserve; (2) first, add the raw materials ≤0.6mm and boron modified phenolic resin powder to the conical mixer in the order of light first and heavy last, mix for 20-30min, and get the premixed powder; (3) then add the granules larger than 0.6mm to the wheel mill, stir for 3-5min, add phenolic resin, stir for 5-8min, add the premixed powder after the granules are completely wet, and continue to mix for 30-40min to get the mixed mud; (4) the mud is pressed under the conditions of temperature 25-35℃ and humidity 40-50% for 8-24h to get the slide plate brick body; (5) after the body is naturally dried for 24h, it is dried in the dryer, the heating rate is 10-15℃ / h, the drying temperature is 230-280℃, and after the temperature reaches the drying temperature, it is kept for 8-10h; (6) the dried body is fired in a nitrogen atmosphere in a nitriding furnace, the firing temperature is 1200-1400℃, and the holding time is 8-12h; (7) after the body is fired, it is subjected to the processes of hoop adding, grinding and coating to become the target product.

2. The method of producing a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate according to claim 1, characterized by, The SiC content in the silicon carbide micropowder is ≥98%, D 50 ≈2.0 μm.

3. The method of producing a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate according to claim 1, characterized by, The metal aluminum powder particle size is ≤0.044mm.

4. The method of producing a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate according to claim 1, characterized by, The boron glass powder particle size is ≤0.044mm, the B2O3 content is ≥14%, and the melting point is 400-800℃.

5. The method of producing a high-temperature sintered Al-Al2O3 slide plate brick added with titanium concentrate according to claim 1, characterized by, The phenolic resin type is PF5323, the boron modified phenolic resin powder decomposition temperature is ≥500℃, the carbon residue rate at 1000℃ is ≥50%, and the free phenol is ≤7%.

Images