Refractory material for steelmaking and preparation method thereof

Abstract

The invention discloses a refractory material for steelmaking and a preparation method thereof. The refractory material is prepared from the following raw material components in parts by weight: 100 to 200 parts of magnesia-calcium clinker, 30 to 50 parts of graphite, 10 to 15 parts of aluminum oxide micro powder, 10 to 20 parts of mineral powder, 70 to 100 parts of liquid phenolic resin, 30 to 60 parts of antioxidant and 30 to 50 parts of thermal shock resistant additive. The refractory material is prepared by taking the magnesia-calcium sand and the graphite as main materials, is good in performance and is suitable for preparing equipment such as a converter, an electric furnace, a refining furnace and a tundish for steelmaking. The strontium zeolite and the celsian in the components are combined for use, so that the compression resistance of the material is improved, the metal powder and the green silicon carbide are combined for use, the oxidation resistance of the material is improved, and the mullite and the alumina spinel are combined for use, so that the thermal shock resistance of the material is improved, and synergistic interaction is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of steelmaking, and in particular relates to a refractory material for steelmaking and a preparation method thereof. Background Art

[0002] Refractory materials for steelmaking are an indispensable and important part of the steel production process, and their performance directly affects the efficiency of the steelmaking process and the quality of products. There are many types of refractory materials for steelmaking, mainly including magnesia carbon bricks, magnesia calcium bricks, alumina silicon bricks, amorphous refractory materials, etc. These materials are widely used in equipment such as converters, electric furnaces, refining furnaces, and tundishes to meet the requirements of refractory performance in different smelting links. During the steelmaking process, refractory materials need to withstand extremely high temperatures, usually not less than 1580℃, so they must have good refractoriness and mechanical strength at high temperatures. Refractory materials must be able to resist chemical erosion by slag and molten metal, especially for equipment such as converters and electric furnaces, which will produce a large amount of high-temperature slag and molten steel during the smelting process, which puts higher requirements on the erosion resistance of refractory materials. In order to reduce heat loss and prevent damage caused by thermal expansion, refractory materials should have low thermal conductivity and thermal expansion coefficient. Due to the drastic temperature changes during steelmaking, refractory materials must have good thermal shock resistance to prevent cracks and fractures caused by sudden temperature changes.

[0003] During the steelmaking process, refractory materials, especially carbon-containing refractory materials (such as magnesia carbon bricks), are easily oxidized at high temperatures, resulting in a shortened service life. Therefore, improving the oxidation resistance of refractory materials is the key. For example, antioxidants (such as metal aluminum powder, silicon powder, magnesium powder, silicon carbide powder, etc.) are added to enhance the antioxidant capacity of the material. Studies have shown that the addition of metal antioxidants alone has limited effect on improving the antioxidant properties of carbon-containing refractories, while the composite addition of metal and non-metal antioxidants (such as 1% Al + 1% B4C, 2.5% Al + 0.4% TiO2, etc.) can significantly improve the antioxidant properties, with an improvement effect of 60-80%. In addition, the addition of calcium boride can also significantly improve the antioxidant properties of magnesium calcium carbon refractories. The mechanism of action of antioxidants includes both thermodynamics and kinetics. From a thermodynamic point of view, the affinity of antioxidants or their products to oxygen is greater than that of carbon to oxygen, so they are oxidized first, protecting carbon from oxidation; from a kinetic point of view, the compounds generated by the reaction of antioxidants with oxygen and carbon monoxide change the microstructure of the material, increase the density, block the pores, and hinder the diffusion of oxygen and reaction products. The oxidation resistance of current steelmaking refractory materials needs to be further improved. Summary of the invention

[0004] The object of the present invention is to provide a refractory material for steelmaking and a preparation method thereof.

[0005] A refractory material for steelmaking comprises the following raw material components in parts by weight: 100-200 parts of magnesia-calcium sand, 30-50 parts of graphite, 10-15 parts of alumina micropowder, 10-20 parts of mineral powder, 70-100 parts of liquid phenolic resin, 30-60 parts of antioxidant and 30-50 parts of thermal shock resistant additive.

[0006] The chemical composition of the magnesium calcium sand is: MgO 55-72wt%, CaO 25-42wt%, SiO2+Al2O3+Fe2O3≤3wt%.

[0007] The mineral powder is a mixture of strontium zeolite and barium feldspar in a mass ratio of 1:3.

[0008] The antioxidant is a mixture of metal powder and green silicon carbide in a mass ratio of 2:1.

[0009] The metal powder is one or more of aluminum powder, silicon powder, magnesium powder and iron powder.

[0010] The anti-thermal shock additive is a mixture of mullite and alumina spinel in a mass ratio of 1:1.

[0011] The method for preparing the refractory material for steelmaking is carried out according to the following steps:

[0012] (1) According to weight proportions, 100-200 parts of magnesium calcium sand, 30-50 parts of graphite, 10-20 parts of mineral powder, 30-60 parts of antioxidant, and 30-50 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0013] (2) adding 10-15 parts of alumina powder to a wet mill and dry mixing for 2-4 minutes, then adding 70-100 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 20-30 minutes and then discharging;

[0014] (3) Pressing the mixture prepared in step (2) into a shape, baking at 600-900° C. for 2-5 hours, and cooling to room temperature to obtain a refractory material for steelmaking.

[0015] The pressing and molding adopts a 630t electric screw brick press.

[0016] Beneficial effects of the present invention: The present invention uses magnesium calcium sand and graphite as main materials to prepare refractory materials with good performance, and is suitable for preparing converters, electric furnaces, refining furnaces, tundishes and other equipment for steelmaking. The combination of strontium zeolite and barium feldspar in the components improves the compressive performance of the material, the combination of metal powder and green silicon carbide improves the oxidation resistance of the material, and the combination of mullite and Alcoa spinel improves the thermal shock resistance of the material, and synergistically enhances the effect. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0018] Example 1

[0019] A refractory material for steelmaking includes the following raw material components in weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of mineral powder, 90 parts of liquid phenolic resin, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and barium feldspar in a mass ratio of 1:3; the antioxidant is a mixture of aluminum powder and green silicon carbide in a mass ratio of 2:1; and the thermal shock resistant additive is a mixture of mullite and Alcoa spinel in a mass ratio of 1:1.

[0020] The method for preparing the refractory material for steelmaking is carried out according to the following steps:

[0021] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of mineral powder, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive were mixed and then passed through a ball mill to grind to a particle size of <80 μm to prepare a co-ground powder;

[0022] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0023] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0024] Example 2

[0025] A refractory material for steelmaking comprises the following raw material components in parts by weight: 100 parts of magnesia calcium sand, 30 parts of graphite, 10 parts of alumina powder, 10 parts of mineral powder, 70 parts of liquid phenolic resin, 30 parts of antioxidant, and 30 parts of thermal shock resistant additive; the chemical composition of the magnesia calcium sand is: 60wt% of MgO, 39wt% of CaO, and 1wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and celsium feldspar in a mass ratio of 1:3; the antioxidant is a mixture of silicon powder and green silicon carbide in a mass ratio of 2:1; and the thermal shock resistant additive is a mixture of mullite and alcoa spinel in a mass ratio of 1:1.

[0026] The preparation method of the refractory material for steelmaking is carried out according to the following steps:

[0027] (1) According to weight proportions, 100 parts of magnesium calcium sand, 30 parts of graphite, 10 parts of mineral powder, 30 parts of antioxidant, and 30 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0028] (2) adding 10 parts of alumina powder to a wet mill and dry mixing for 2 minutes, then adding 70 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 20 minutes and then discharging;

[0029] (3) Pressing the mixture prepared in step (2) into a shape, baking at 600° C. for 5 h, and cooling to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0030] Example 3

[0031] A refractory material for steelmaking comprises the following raw material components in parts by weight: 200 parts of magnesia-calcium sand, 50 parts of graphite, 15 parts of alumina powder, 20 parts of mineral powder, 100 parts of liquid phenolic resin, 60 parts of antioxidant, and 50 parts of thermal shock resistant additive; the chemical composition of the magnesia-calcium sand is: 70wt% of MgO, 27wt% of CaO, and 3wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and celsium feldspar in a mass ratio of 1:3; the antioxidant is a mixture of magnesium powder and green silicon carbide in a mass ratio of 2:1; and the thermal shock resistant additive is a mixture of mullite and alcoa spinel in a mass ratio of 1:1.

[0032] The preparation method of the refractory material for steelmaking is carried out according to the following steps:

[0033] (1) According to weight proportions, 200 parts of magnesium calcium sand, 50 parts of graphite, 20 parts of mineral powder, 60 parts of antioxidant, and 50 parts of thermal shock resistant additive were mixed and then passed through a ball mill to grind to a particle size of <80 μm to prepare a co-ground powder;

[0034] (2) adding 15 parts of alumina powder to a wet mill and dry mixing for 4 minutes, then adding 100 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 30 minutes and then discharging;

[0035] (3) The mixed material prepared in step (2) is pressed into shape, baked at 900° C. for 2 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0036] Comparative Example 1

[0037] A refractory material for steelmaking includes the following raw material components in weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of strontium zeolite, 90 parts of liquid phenolic resin, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the antioxidant is a mixture of aluminum powder and green silicon carbide in a mass ratio of 2:1; the thermal shock resistant additive is a mixture of mullite and Alcoa spinel in a mass ratio of 1:1.

[0038] The method for preparing the refractory material for steelmaking is carried out according to the following steps:

[0039] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of strontium zeolite, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0040] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0041] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0042] Comparative Example 2

[0043] A refractory material for steelmaking includes the following raw material components in parts by weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of celsium feldspar, 90 parts of liquid phenolic resin, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the antioxidant is a mixture of aluminum powder and green silicon carbide in a mass ratio of 2:1; the thermal shock resistant additive is a mixture of mullite and Alcoa spinel in a mass ratio of 1:1.

[0044] The method for preparing the refractory material for steelmaking is carried out according to the following steps:

[0045] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of celsium feldspar, 45 parts of antioxidant, and 40 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm by a ball mill to prepare a co-ground powder;

[0046] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0047] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0048] Comparative Example 3

[0049] A refractory material for steelmaking includes the following raw material components in weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of mineral powder, 90 parts of liquid phenolic resin, 45 parts of aluminum powder, and 40 parts of thermal shock resistant additive. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and celsium feldspar in a mass ratio of 1:3; and the thermal shock resistant additive is a mixture of mullite and alumina spinel in a mass ratio of 1:1.

[0050] The method for preparing the refractory material for steelmaking is carried out according to the following steps:

[0051] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of mineral powder, 45 parts of aluminum powder, and 40 parts of thermal shock resistant additive were mixed and then passed through a ball mill to grind to a particle size of <80 μm to prepare a co-ground powder;

[0052] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0053] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0054] Comparative Example 4

[0055] A refractory material for steelmaking includes the following raw material components in weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of mineral powder, 90 parts of liquid phenolic resin, 45 parts of green silicon carbide, and 40 parts of thermal shock resistant additive. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and barium feldspar in a mass ratio of 1:3; and the thermal shock resistant additive is a mixture of mullite and alumina spinel in a mass ratio of 1:1.

[0056] The preparation method of the refractory material for steelmaking is carried out according to the following steps:

[0057] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of mineral powder, 45 parts of green silicon carbide, and 40 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0058] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0059] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0060] Comparative Example 5

[0061] A refractory material for steelmaking includes the following raw material components in parts by weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of mineral powder, 90 parts of liquid phenolic resin, 45 parts of antioxidant, and 40 parts of mullite. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and celsium feldspar in a mass ratio of 1:3; the antioxidant is a mixture of aluminum powder and green silicon carbide in a mass ratio of 2:1.

[0062] The preparation method of the refractory material for steelmaking is carried out according to the following steps:

[0063] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of mineral powder, 45 parts of antioxidant, and 40 parts of mullite were mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0064] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0065] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0066] Comparative Example 6

[0067] A refractory material for steelmaking includes the following raw material components in parts by weight: 150 parts of magnesia calcium sand, 40 parts of graphite, 12 parts of alumina powder, 16 parts of mineral powder, 90 parts of liquid phenolic resin, 45 parts of antioxidant, and 40 parts of Alcoa spinel. The chemical composition of the magnesia calcium sand is: 65wt% of MgO, 33wt% of CaO, and 2wt% of SiO2+Al2O3+Fe2O3; the mineral powder is a mixture of strontium zeolite and celsium feldspar in a mass ratio of 1:3; the antioxidant is a mixture of aluminum powder and green silicon carbide in a mass ratio of 2:1.

[0068] The preparation method of the refractory material for steelmaking is carried out according to the following steps:

[0069] (1) According to weight proportions, 150 parts of magnesium calcium sand, 40 parts of graphite, 16 parts of mineral powder, 45 parts of antioxidant, and 40 parts of Alcoa spinel are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder;

[0070] (2) adding 12 parts of alumina powder to a wet mill and dry mixing for 3 minutes, then adding 90 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 25 minutes and then discharging;

[0071] (3) The mixed material prepared in step (2) is pressed into shape, baked at 800° C. for 3 h, and cooled to room temperature to obtain a refractory material for steelmaking; the pressing and molding is performed using a 630t electric screw brick press.

[0072] Experimental example:

[0073] According to the standard GB / T 5072-2008, the refractory materials prepared in Examples 1-3 and Comparative Examples 1-2 were made into cylinders with a diameter of 50 mm, and their room temperature compressive strength was measured. The experimental results were statistically analyzed using SPSS24.0 software, and the measurement data results were expressed as x±(mean±standard deviation). The Kolmogorov-Smirnov test method was used for data normality test. For data that met the normal distribution, the mean difference between the two groups was compared using the t test, and P<0.05 was considered statistically significant. The measurement results are shown in Table 1:

[0074] Table 1

[0075]

[0076] Note: * represents P < 0.05 compared with the group in Example 1.

[0077] The oxidation resistance of the refractory materials prepared in Examples 1-3 and Comparative Examples 3-4 was measured according to the standard GB / T 13244 "Test Method for Oxidation Resistance of Carbon-Containing Refractory Materials". The decarburization layer thickness of the refractory materials at 1000°C and 1200°C is recorded in Table 2:

[0078] Table 2

[0079]

[0080] Note: * represents P < 0.05 compared with the group in Example 1.

[0081] According to GB / T 30873-2014 "Test Method for Thermal Shock Resistance of Refractory Materials", the thermal shock resistance of the refractory materials prepared in Examples 1-3 and Comparative Examples 5-6 was measured, and the number of thermal shock resistance tests and the damage rate of the heated end surface experienced by the refractory materials were recorded in Table 3:

[0082] Table 3

[0083]

[0084] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A refractory material for steelmaking, characterized in that: The invention comprises the following raw material components in parts by weight: 100-200 parts of magnesium calcium sand, 30-50 parts of graphite, 10-15 parts of alumina micropowder, 10-20 parts of mineral powder, 70-100 parts of liquid phenolic resin, 30-60 parts of antioxidant and 30-50 parts of thermal shock resistant additive.

2. The refractory material for steelmaking according to claim 1, characterized in that: The chemical composition of the magnesium calcium sand is: MgO 55-72wt%, CaO 25-42wt%, SiO2+Al2O3+Fe2O3≤3wt%.

3. The refractory material for steelmaking according to claim 1, characterized in that: The mineral powder is a mixture of strontium zeolite and barium feldspar in a mass ratio of 1:

3.

4. The refractory material for steelmaking according to claim 1, characterized in that: The antioxidant is a mixture of metal powder and green silicon carbide in a mass ratio of 2:

1.

5. The refractory material for steelmaking according to claim 1, characterized in that: The metal powder is one or more of aluminum powder, silicon powder, magnesium powder and iron powder.

6. The refractory material for steelmaking according to claim 1, characterized in that: The anti-thermal shock additive is a mixture of mullite and alumina spinel in a mass ratio of 1:

1.

7. The method for preparing the refractory material for steelmaking according to claim 1, characterized in that: Follow these steps: (1) According to weight proportions, 100-200 parts of magnesium calcium sand, 30-50 parts of graphite, 10-20 parts of mineral powder, 30-60 parts of antioxidant, and 30-50 parts of thermal shock resistant additive are mixed and then ground into a particle size of <80 μm in a ball mill to prepare a co-ground powder; (2) adding 10-15 parts of alumina powder to a wet mill and dry mixing for 2-4 minutes, then adding 70-100 parts of liquid phenolic resin, and finally adding the co-ground powder prepared in step (1), mixing for 20-30 minutes and then discharging; (3) Pressing the mixture prepared in step (2) into a shape, baking at 600-900° C. for 2-5 hours, and cooling to room temperature to obtain a refractory material for steelmaking.

8. The method for preparing a refractory material for steelmaking according to claim 7, characterized in that: The pressing and molding adopts a 630t electric screw brick press.

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