A long-life electric furnace cover and its preparation method

Abstract

This invention discloses a long-life electric furnace cover and its preparation method. 60-80% silicon carbide particles and 20-40% vanadium-containing steel slag powder are mixed uniformly by mass percentage to obtain granulated material. The granulated material is then granulated, and the resulting particles are dried at 70-90℃ for 5-10 hours, followed by heat treatment at 600-800℃ for 1-3 hours. The particles are then sieved to obtain composite silicon carbide granulated material with a particle size of 1-0 mm. 20-40% 8-1 mm mullite particles, 15-25% 3-1 mm tabular corundum, and 15-25%... The following ingredients are used: 1-0 mm plate-shaped corundum, 1-3% silicon carbide particles, 3-5% composite silicon carbide granules, 1-5% fused white corundum powder, 5-10% corundum micro powder, 1-5% silica micro powder, 0.2-0.6% explosion-proof fiber, 0.5-1% water-reducing agent, and 1-3% calcium aluminate cement. 4-7% water is added and mixed evenly. The mixture is poured into a mold and vibrated to form the desired shape. After natural curing in the mold for 24 hours, the mixture is demolded, then naturally cured for 2-3 days, and baked at 200-250℃ for 30-40 hours. The furnace lid of this invention has a long service life.

Description

Technical fields:

[0001] This invention belongs to the field of refractory materials technology, and specifically relates to a long-life electric furnace cover and its preparation method. Background technology:

[0002] Electric arc furnace (EAF) steelmaking refers to the smelting process that uses induction heating to generate an electric arc between graphite electrodes and the furnace charge, melting alloys and scrap steel through arc radiation, convection, and heat conduction, followed by oxidation and reduction. It boasts advantages such as short processes, simple equipment, low energy consumption, high utilization rate, and significant energy-saving and emission-reduction effects. However, the harsh conditions of EAF steelmaking, including high temperatures, erosion, and melting, cause severe damage to the refractory materials used in the furnace, affecting operational efficiency. The furnace cover is a crucial component, enduring complex conditions such as high temperatures, rapid heating and cooling, and high-temperature molten metal splashing / erosion during operation. This can easily lead to cracking, peeling, and damage of the refractory materials in the furnace cover, resulting in reduced performance and lifespan. To address these issues, researchers have improved the structure, mechanical strength, and thermal shock stability of electric furnace cover refractory materials by introducing alumina hollow spheres, andalusite, controlled mullite, and binders. However, the low-melting-point phases generated in the refractory matrix at high temperatures are difficult to control, resulting in unstable high-temperature performance and low resistance to high-temperature melt erosion, leading to a decrease in service life.

[0003] Vanadium-containing steel slag typically refers to the water-quenched slag produced after blast furnace smelting of vanadium-titanium magnetite, and is classified as general solid waste. Up to 3 million tons of vanadium-containing steel slag are produced annually from blast furnaces, and are generally discarded as waste. Current research on the resource utilization of vanadium-containing steel slag mainly focuses on extracting vanadium, iron, calcium, and other metallic elements using various methods. However, how to effectively utilize the valuable components of vanadium-containing steel slag to achieve resource recycling still requires in-depth research and engineering applications.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention:

[0005] The purpose of this invention is to provide a long-life electric furnace cover and its preparation method, thereby overcoming the defects in the prior art.

[0006] To achieve the above objectives, the present invention provides a long-life electric furnace cover and its preparation method, the steps of which are: (1) mixing 60-80% silicon carbide particles and 20-40% vanadium-containing steel slag powder evenly according to mass percentage to obtain granulation material;

[0007] (2) Granulate the granules obtained in step (1), dry the granules at 70-90℃ for 5-10 hours, heat treat the granules at 600-800℃ for 1-3 hours, and sieve the granules to obtain composite silicon carbide granules with a particle size of 1-0 mm.

[0008] (3) Mix 20-40% of 8-1mm mullite particles, 15-25% of 3-1mm tabular corundum, 15-25% of 1-0mm tabular corundum, 1-3% of silicon carbide particles, 3-5% of composite silicon carbide granules, 1-5% of fused white corundum powder, 5-10% of corundum micro powder, 1-5% of silica micro powder, 0.2-0.6% of explosion-proof fiber, 0.5-1% of water-reducing agent, 1-3% of calcium aluminate cement, and 4-7% of water evenly, pour into a mold and vibrate to form.

[0009] (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 2-3 days and baked at 200-250℃ for 30-40 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

[0010] Preferably, in the technical solution, the particle size of the silicon carbide particles is less than 0.5 mm, and the mass percentage of silicon carbide in the silicon carbide particles is ≥97.0%.

[0011] Preferably, in the technical solution, the particle size of the vanadium-containing steel slag powder is less than 45 micrometers, and its composition by percentage is: V2O5 1.5-3%, SiO2 <13%, and CaO 35-40%.

[0012] Preferably, in the technical solution, 10-20% water mist is sprayed onto the granulated material during the granulation process.

[0013] Preferably, in the technical solution, the mass percentage of Al2O3 in the mullite particles is greater than 70.0% and the mass percentage of Fe2O3 is less than 1.0%.

[0014] Preferably, in the technical solution, the mass percentage of Al2O3 in the tabular corundum is greater than 99%.

[0015] Preferably, in the technical solution, the particle size of the fused white fused alumina powder is ≤0.088 mm, and the mass percentage of Al2O3 in the fused white fused alumina powder is greater than 99%.

[0016] Preferably, in the technical solution, the particle size of the corundum micro powder is ≤0.002 mm, and the mass percentage content of Al2O3 in the corundum micro powder is ≥99.5%.

[0017] Preferably, in the technical solution, the particle size of the silicon micro powder is ≤0.005 mm, and the mass percentage content of SiO2 in the silicon micro powder is ≥94 wt%.

[0018] Preferably, in the technical solution, the length of the explosion-proof fiber is 5-7 mm and the melting point is 160±5℃.

[0019] Preferably, in the technical solution, the water-reducing agent is sodium tripolyphosphate or sodium hexametaphosphate.

[0020] Preferably, in the technical solution, the particle size of the calcium aluminate cement is ≤0.044 mm, and the mass percentage of Al2O3 in the calcium aluminate cement is ≥75%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] By utilizing the regulatory effect of vanadium-containing steel slag in pre-formed composite silicon carbide granules on the oxidation and reaction behavior of silicon carbide particles, the composition and microstructure of the prepared refractory material are controlled. This leverages the advantages of silicon carbide in thermal shock stability and slag erosion resistance while avoiding its tendency to oxidize at high temperatures. Consequently, the resulting long-life electric furnace cover exhibits high thermal shock stability and excellent resistance to molten slag erosion. Furthermore, the distribution and development of phases such as corundum, mullite, and silicon carbide are controlled to enhance the microstructure, resulting in a long-life electric furnace cover with moderate density and high mechanical strength. Detailed implementation method:

[0023] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0024] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0025] Example 1

[0026] A long-life electric furnace cover and its preparation method, the steps of which are: (1) Mixing 60% silicon carbide particles and 40% vanadium-containing steel slag powder evenly according to mass percentage to obtain granulation material;

[0027] (2) Granulate the granules obtained in step (1), dry the granules at 70°C for 5 hours, heat treat the granules at 600°C for 3 hours, and sieve the granules to obtain composite silicon carbide granules with a particle size of 1-0 mm.

[0028] (3) Mix 30% of 8-1mm mullite particles, 25% of 3-1mm tabular corundum, 24% of 1-0mm tabular corundum, 2% of silicon carbide particles, 3% of composite silicon carbide granules, 2% of fused white corundum powder, 8% of corundum micro powder, 3% of silica micro powder, 0.2% of explosion-proof fiber, 0.8% of sodium tripolyphosphate, 2% of calcium aluminate cement, and 5% of water evenly, pour into a mold and vibrate to form.

[0029] (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 3 days and baked at 220℃ for 30 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

[0030] The long-life electric furnace cover prepared in this embodiment was tested and found to have the following characteristics: bulk density 2.85 g / cm3; flexural strength 22 MPa and compressive strength 60 MPa after 24 hours at 110℃; flexural strength retention rate of 62% after 5 water cooling cycles at 1100℃; and excellent resistance to molten slag erosion.

[0031] Example 2

[0032] A long-life electric furnace cover and its preparation method, the steps of which are: (1) Mixing 60% silicon carbide particles and 40% vanadium-containing steel slag powder evenly according to mass percentage to obtain granulation material;

[0033] (2) The granulated material obtained in step (1) is granulated, the obtained material particles are dried at 90°C for 10 hours, the material particles are then heat-treated at 800°C for 2 hours, and the material particles are screened to obtain composite silicon carbide granulated material with a particle size of 1-0 mm.

[0034] (3) Mix 28% of 8-1mm mullite particles, 22% of 3-1mm tabular corundum, 20% of 1-0mm tabular corundum, 3% of silicon carbide particles, 5% of composite silicon carbide granules, 3% of fused white corundum powder, 10% of corundum micro powder, 5% of silica micro powder, 0.5% of explosion-proof fiber, 0.5% of sodium tripolyphosphate, 3% of calcium aluminate cement, and 7% of water evenly, pour into a mold and vibrate to form.

[0035] (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 2 days and baked at 200℃ for 40 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

[0036] The long-life electric furnace cover prepared in this embodiment was tested and found to have the following characteristics: bulk density 2.90 g / cm3; flexural strength 28 MPa and compressive strength 66 MPa after 24 hours at 110℃; flexural strength retention rate of 75% after 5 water cooling cycles at 1100℃; and excellent resistance to molten slag erosion.

[0037] Example 3

[0038] A long-life electric furnace cover and its preparation method, the steps of which are: (1) 80% silicon carbide particles and 20% vanadium-containing steel slag powder are mixed evenly according to mass percentage to obtain granulation material;

[0039] (2) Granulate the granules obtained in step (1), dry the granules at 80°C for 8 hours, heat treat the granules at 800°C for 1 hour, and sieve the granules to obtain composite silicon carbide granules with a particle size of 1-0 mm.

[0040] (3) Mix 37% of 8-1mm mullite particles, 20% of 3-1mm tabular corundum, 15% of 1-0mm tabular corundum, 3% of silicon carbide particles, 5% of composite silicon carbide granules, 3% of fused white corundum powder, 9% of corundum micro powder, 4% of silica micro powder, 0.5% of explosion-proof fiber, 0.5% of sodium hexametaphosphate, 3% of calcium aluminate cement, and 7% of water evenly, pour into a mold and vibrate to form.

[0041] (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 2 days and baked at 250℃ for 40 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

[0042] The long-life electric furnace cover prepared in this embodiment was tested and found to have the following characteristics: bulk density 2.83 g / cm3; flexural strength 22 MPa and compressive strength 58 MPa after 24 hours at 110℃; flexural strength retention rate of 65% after 5 water cooling cycles at 1100℃; and excellent resistance to molten slag erosion.

[0043] Example 4

[0044] A long-life electric furnace cover and its preparation method, the steps of which are: (1) 80% silicon carbide particles and 20% vanadium-containing steel slag powder are mixed evenly according to mass percentage to obtain granulation material;

[0045] (2) Granulate the granules obtained in step (1), dry the granules at 80°C for 5 hours, heat treat the granules at 600°C for 2 hours, and sieve the granules to obtain composite silicon carbide granules with a particle size of 1-0 mm.

[0046] (3) Mix 38% of 8-1mm mullite particles, 22% of 3-1mm tabular corundum, 16% of 1-0mm tabular corundum, 1% of silicon carbide particles, 3% of composite silicon carbide granules, 3% of fused white corundum powder, 9% of corundum micro powder, 4% of silica micro powder, 0.5% of explosion-proof fiber, 0.5% of sodium hexametaphosphate, 3% of calcium aluminate cement, and 6% of water evenly, pour into a mold and vibrate to form.

[0047] (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 3 days and baked at 200℃ for 30 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

[0048] The long-life electric furnace cover prepared in this embodiment was tested and found to have the following characteristics: bulk density 2.84 g / cm3; flexural strength 26 MPa and compressive strength 65 MPa after 24 hours at 110℃; flexural strength retention rate of 63% after 5 water cooling cycles at 1100℃; and excellent resistance to molten slag erosion.

[0049] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A long-life electric furnace cover, characterized in that: (1) Mix 60-80% silicon carbide particles and 20-40% vanadium-containing steel slag powder evenly by mass percentage to obtain granulation material; wherein the particle size of the vanadium-containing steel slag powder is less than 45 micrometers, and its composition by percentage content is: V2O5 1.5-3%, SiO2 <13%, CaO 35-40%; (2) Granulate the granules obtained in step (1), dry the granules at 70-90℃ for 5-10 hours, heat treat the granules at 600-800℃ for 1-3 hours, and sieve the granules to obtain composite silicon carbide granules with a particle size of 1-0 mm. (3) Mix 20-40% of 8-1 mm mullite particles, 15-25% of 3-1 mm tabular corundum, 15-25% of 1-0 mm tabular corundum, 1-3% of silicon carbide particles, 3-5% of composite silicon carbide granules, 1-5% of fused white corundum powder, 5-10% of corundum micro powder, 1-5% of silica micro powder, 0.2-0.6% of explosion-proof fiber, 0.5-1% of water-reducing agent, and 1-3% of calcium aluminate cement by mass percentage, and add 4-7% water. Pour the mixture into a mold and vibrate to form the product. The mullite particles contain more than 70.0% Al2O3 and less than 1.0% Fe2O3 by mass percentage. (4) After curing naturally in the mold for 24 hours, the mold is removed and then cured naturally for 2-3 days and baked at 200-250℃ for 30-40 hours. The mold is then cooled to room temperature to obtain a long-life electric furnace cover.

2. The long-life electric furnace cover according to claim 1, characterized in that: The mass percentage of Al2O3 in tabular corundum is greater than 99%.

3. The long-life electric furnace cover according to claim 1, characterized in that: The particle size of the fused white fused alumina powder is ≤0.088 mm, and the mass percentage of Al2O3 in the fused white fused alumina powder is greater than 99%.

4. The long-life electric furnace cover according to claim 1, characterized in that: The particle size of corundum micro powder is ≤0.002 mm, and the mass percentage of Al2O3 in the corundum micro powder is ≥99.5%.

5. The long-life electric furnace cover according to claim 1, characterized in that: The particle size of the silicon micro powder is ≤0.005 mm, and the mass percentage of SiO2 in the silicon micro powder is ≥94 wt%.

6. The long-life electric furnace cover according to claim 1, characterized in that: The water-reducing agent is sodium tripolyphosphate or sodium hexametaphosphate.

7. The long-life electric furnace cover according to claim 1, characterized in that: The particle size of calcium aluminate cement is ≤0.044 mm, and the mass percentage of Al2O3 in calcium aluminate cement is ≥75%.