Converter lower nozzle added with Al2O3-MgO composite powder and preparation method thereof

Abstract

This invention discloses a converter outlet with Al2O3-MgO composite powder and its preparation method, belonging to the field of refractory materials technology. The drain outlet comprises 60%-65% MAS-76 aluminum-magnesium spinel and 35%-40% co-milled powder, with the sum of their weight percentages being 100%; an additional 4%-5% thermosetting phenolic resin binder is added to the total weight percentage; the co-milled powder comprises 6%-12% MAS-76 aluminum-magnesium spinel fine powder, 18%-28% Al2O3-MgO composite fine powder, 4%-5% zircon fine powder, and 1%-2% metallic silicon powder; the chemical composition and content of the Al2O3-MgO composite fine powder are as follows: MgO content is 56%-66%, Al2O3 content is 25%-35%, SiO2 content is 8%-9%, CaO content is 0.03-0.05%, and Fe2O3 content is 0.09-0.12%. This invention uses a specially treated Al2O3-MgO composite powder to replace α-Al2O3 micro powder, carbon black, and graphite, forming a novel clean steel outlet material system for converters. This system possesses excellent slag corrosion resistance that meets current steelmaking requirements and has an excellent service life.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials technology, and more specifically, relates to a converter outlet with Al2O3-MgO composite powder and its preparation method. Background Technology

[0002] Currently, the material used for the outlet of ordinary converters is generally aluminum-carbon, whose main components are alumina, metallic aluminum and aluminum-carbon materials such as carbon black and graphite. It can meet the requirements for smelting ordinary carbon steel, but it cannot meet the requirements for the rapidly growing clean steel and special steel smelting. It has poor resistance to alkaline steel slag erosion and corrosion, and carbon black, graphite, α-Al2O3 micro powder and tabular corundum are relatively expensive.

[0003] The applicant previously filed a Chinese patent application with the number CN202011634315.3, published on May 7, 2021, which disclosed a carbon-free steel ladle drain outlet and its preparation method, belonging to the field of refractory materials technology. Its composition and weight percentage are: 60%-64% MAS-76 aluminum-magnesium spinel and 36%-40% co-milled powder, with a total percentage of 100%; an additional 4%-5% thermosetting phenolic resin binder is added to the total weight percentage, wherein the co-milled powder includes 10%-18% MAS-76 aluminum-magnesium spinel fine powder, 7%-13% α-Al2O3 micro powder, 8%-10% zircon fine powder and 5% metallic silicon powder. This invention introduces MAS-76 aluminum-magnesium spinel as particulate aggregate, which improves the cleanliness and quality of molten steel, enhances product performance, and reduces production costs through carbon-free steel ladle outlet. The outlet of the carbon-free steel ladle has high temperature resistance, slag resistance, and spalling resistance, and the surface of the outlet has more MAS-76 aluminum-magnesium spinel particles and fine powder, which have excellent erosion resistance.

[0004] However, while the above-mentioned solutions have improved the high-temperature resistance and slag corrosion resistance of the outlet to some extent, when used in large converters, the average service life of the outlet can no longer meet the current steelmaking needs. Therefore, it is necessary to further improve the performance of the outlet to cope with the increasing steelmaking demands.

[0005] This product uses a specially treated, renewable Al2O3-MgO composite powder to replace alumina powder, carbon black, and graphite, forming a completely new material system for clean steel outlets in converters. This meets the requirements for cleanliness and high-quality steel grades in steelmaking, while simultaneously reusing resources and reducing production costs. The renewable Al2O3-MgO composite powder is recycled, sorted, and iron-removed, then sintered at temperatures above 1800℃ in an ultra-high temperature tunnel kiln. It has high bulk density, high mineral phase content, well-developed grains, uniform structure, and stable quality, providing a high-performance converter outlet with excellent resistance to erosion, spalling, slag corrosion, and thermal shock. Summary of the Invention

[0006] 1. The problem to be solved

[0007] To address the issue that the performance of existing downpipes can no longer meet the steelmaking requirements of large converters, this invention provides a converter downpipe with added Al2O3-MgO composite powder and its preparation method. Through research and experiments on the composition of existing downpipe materials, a specially treated Al2O3-MgO composite powder is used to replace α-Al2O3 micro powder, carbon black, and graphite, forming a novel clean steel downpipe material system for converters. This system possesses excellent slag corrosion resistance that meets current steelmaking requirements and has an exceptionally long service life.

[0008] 2. Technical Solution

[0009] To solve the above problems, the present invention adopts the following technical solution.

[0010] A converter outlet with added Al2O3-MgO composite powder, the raw materials of which include 60%-65% MAS-76 aluminum-magnesium spinel and 35%-40% co-milled powder, the sum of the weight percentages of the two is 100%; and an additional thermosetting phenolic resin binder accounting for 4% to 5% of the total weight percentage.

[0011] The co-milled powder comprises 6%–12% MAS-76 aluminum-magnesium spinel fine powder, 18%–28% Al2O3-MgO composite fine powder, 4%–5% zircon fine powder, and 1%–2% metallic silicon powder.

[0012] The chemical composition and content of the Al2O3-MgO composite powder are as follows: MgO content is 56% to 66%, Al2O3 content is 25% to 35%, SiO2 content is 8% to 9%, CaO content is 0.03% to 0.05%, and Fe2O3 content is 0.09% to 0.12%.

[0013] As an optional implementation, the fine powder of the Al2O3-MgO composite powder has a particle size of 500 mesh.

[0014] As an optional implementation, the Al2O3-MgO composite powder is obtained by recycling steel ladle slides used in steel plants, sorting them, sintering them at 1380°C in an oxidizing atmosphere, and then grinding them in a ball mill after passing through a jaw crusher, hammer crusher, and iron removal.

[0015] As an optional implementation, the 60%-65% MAS-76 aluminum-magnesium spinel comprises 15% MAS-76 aluminum-magnesium spinel with a grain size of 5-3 mm, 30% MAS-76 aluminum-magnesium spinel with a grain size of 3-1 mm, and 15%-20% MAS-76 aluminum-magnesium spinel with a grain size of 1-0 mm.

[0016] As an optional implementation, the MAS-76 aluminum-magnesium spinel fine powder has a particle size of 325 mesh, and the chemical composition and content of the MAS-76 aluminum-magnesium spinel are as follows: Al2O3 content is 75.58%, MgO content is 23.54%, CaO content is 0.3%, SiO2 content is 0.25%, and Fe2O3 content is 0.23%.

[0017] As an optional implementation, the MAS-76 aluminum-magnesium spinel and MAS-76 aluminum-magnesium spinel fine powder are industrial MAS-76 aluminum-magnesium spinel that has undergone a multi-stage homogenization process and has been sintered at a high temperature of over 1800°C in an ultra-high temperature tunnel kiln.

[0018] As an optional embodiment, the zircon fine powder has a particle size of 325 mesh, and the chemical composition and content of the zircon fine powder are as follows: ZrO2 content 66.25%, SiO2 content 32.50%, TiO2 content 0.33%, Al2O3 content 0.37%, Fe2O3 content 0.16%, CaO content 0.05%, MgO content 0.02%, Na2O content 0.01%, and K2O content 0.01%.

[0019] As an optional implementation, the particle size of the metallic silicon powder is 325 mesh, and the chemical composition and content of the metallic silicon powder are as follows: Si content is 98.6%, Fe content is 0.54%, Al content is 0.49%, and Ca content is 0.36%.

[0020] The above-mentioned method for preparing the converter drain nozzle with added Al2O3-MgO composite powder includes the following steps:

[0021] Step 1: Preparation of co-milled powder: MAS-76 aluminum-magnesium spinel fine powder, regenerated Al2O3-MgO composite powder, zircon fine powder and metallic silicon powder are mixed evenly according to weight percentage to obtain co-milled powder;

[0022] Step 2, Granular Material Batching: Mix MAS-76 aluminum-magnesium spinel with a particle size of 5-3mm, MAS-76 aluminum-magnesium spinel with a particle size of 3-1mm, and MAS-76 aluminum-magnesium spinel with a particle size of 1-0mm evenly according to the weight percentage to obtain granular material.

[0023] Step 3, Mixing: After dry mixing the granules for 3-5 minutes, slowly add the thermosetting phenolic resin binder and wet mix for 6-8 minutes. Finally, add the co-milling powder and mix for 40-50 minutes before milling to obtain the mixture.

[0024] Step 4: Molding: Press the mixture into a semi-finished blank;

[0025] Step 5, Drying: After air-drying the billets naturally for 24 hours, place them in a tunnel natural gas drying kiln and dry them according to the set curve: the initial temperature upon entering the kiln is 20℃; in the first 0-3 hours, the temperature increases from 20℃ to 90℃; in the 3rd-6th hours, the temperature increases from 90℃ to 120℃; in the 6th-8th hours, the temperature increases from 120℃ to 150℃; in the 8th-10th hours, the temperature increases from 150℃ to 180℃; in the 10th-12th hours, the temperature increases from 180℃ to 210℃, and is held at this temperature for 12 hours; the total drying time is 24 hours.

[0026] Step Six: Shelling: Shell the blank obtained in Step Five. Rotate and apply fire clay to the outer wall of the sprue, then put on the steel shell. Invert the sprue into the fixture and press it to the set position. Remove the sprue. Press the shell and clean the fire clay overflowing from the upper part of the sprue. Remove the sprue from the fixture. After removing the sprue, place it with the upper opening facing down to clean the fire clay from the other opening. Perform the first inspection on the product. If the inspection is qualified, place the sprue with the larger end facing down on the frame. If the inspection is not qualified, adjust the limit block or use a tool to gently tap the iron shell to make it qualified.

[0027] Step 7, Shell Drying: After shelling, the product is naturally cured at room temperature for 4-8 hours before drying. Currently, a natural gas tunnel drying kiln is used for drying. The drying temperature curve is as follows: In the first 0-1 hour, the temperature rises from 30℃ to 80℃; in the second-3 hours, the temperature rises from 80℃ to 120℃; in the fourth-5 hours, the temperature rises from 120℃ to 150℃ and is held at this temperature for 8 hours; the total drying time is 13 hours.

[0028] Step 8, Packaging: After drying, remove from the kiln and let it air dry to room temperature. Check the dimensions and appearance according to the drawing requirements and appearance standards, and then pack it into boxes.

[0029] As an alternative implementation, in step three, the granular material is added to a wet mill for dry mixing, and in step four, the mixture is pressed into shape on a 1200t electric screw press.

[0030] 3. Beneficial effects

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The present invention provides a converter drain outlet with Al2O3-MgO composite powder. The Al2O3-MgO composite powder with special treatment is used to replace α-Al2O3 micro powder, carbon black and graphite, which can form a brand-new clean steel drain outlet material system for converters. Compared with the existing converter drain outlets, the average erosion rate is ≤1mm / time, which is lower than the erosion rate of existing aluminum-carbon products ≥3mm / time. The average service life reaches about 20 times / piece, which meets the rapidly growing requirements for clean steel and special steelmaking.

[0033] (2) The present invention provides a converter outlet with added Al2O3-MgO composite powder. MAS-76 aluminum-magnesium spinel has a high bulk density, high mineral phase content, well-developed grains, uniform structure, and stable quality. Compared with the traditional technology that uses magnesia or corundum, the performance of the outlet is more stable.

[0034] (3) The present invention provides a converter outlet with added Al2O3-MgO composite powder. MAS-76 aluminum-magnesium spinel has a high density. During the mixing process, it can be dispersed on the periphery of the mixture under longitudinal pressure. After molding, the outlet surface has more MAS-76 aluminum-magnesium spinel particles and fine powder. The outlet surface is in direct contact with molten steel and has good anti-erosion performance.

[0035] (4) The present invention provides a converter outlet with Al2O3-MgO composite powder. The Al2O3-MgO composite powder is prepared by recycling the ladle slide used in steel plants, sorting it, firing it at 1380°C in an oxidizing atmosphere, and then grinding it in a ball mill after passing through a jaw crusher, hammer crusher, iron removal, etc. The above process, especially the high temperature pretreatment process, results in high mineral phase content, well-developed grains, uniform structure, stable quality, and good resistance to erosion, spalling, slag corrosion and thermal shock. Detailed Implementation

[0036] Exemplary embodiments of the present invention are described in detail below. While these exemplary embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be implemented and various changes may be made to the invention without departing from its spirit and scope. The more detailed description of embodiments of the invention below is not intended to limit the scope of the claimed invention, but is merely illustrative and does not limit the description of the features and characteristics of the invention, in order to suggest the best mode for carrying out the invention and to enable those skilled in the art to practice it. Therefore, the scope of the invention is defined only by the appended claims.

[0037] Table 1 shows the particle shape and percentage of the ingredients used in each embodiment of the present invention; Table 2 shows the physicochemical properties and average service life parameters of the converter drain outlet with added recycled Al2O3-MgO composite powder obtained in Examples 1 to 4 and the existing aluminum-carbon converter drain outlet.

[0038] Example 1

[0039] A converter outlet with added recycled Al2O3-MgO composite powder has the following raw material composition and weight percentage: 65% MAS-76 aluminum-magnesium spinel, 35% co-milled powder, and the sum of the total weight percentages is 100%; an additional 4% thermosetting phenolic resin binder is added to the total weight percentage. The co-milled powder is prepared by uniformly mixing 6% MAS-76 aluminum-magnesium spinel fine powder, 23% Al2O3-MgO composite powder fine powder, 4% zircon fine powder and 2% metallic silicon powder.

[0040] The MAS-76 aluminum-magnesium spinel and MAS-76 aluminum-magnesium spinel fine powder are produced by multi-stage homogenization of MAS-76 aluminum-magnesium spinel and sintering at high temperatures above 1800℃ in an ultra-high temperature tunnel kiln. They have high bulk density, high mineral phase content, well-developed grains, uniform structure, stable quality, and good resistance to erosion, spalling, slag corrosion and thermal shock.

[0041] The MAS-76 aluminum-magnesium spinel has a particle size of 5-3 mm, 3-1 mm, and 1-0 mm, with the following weight percentages for each particle size: 15% MAS-76 aluminum-magnesium spinel with a particle size of 5-3 mm, 30% MAS-76 aluminum-magnesium spinel with a particle size of 3-1 mm, and 20% MAS-76 aluminum-magnesium spinel with a particle size of 1-0 mm. The chemical composition and content of the MAS-76 aluminum-magnesium spinel are as follows: Al2O3 content is 75.58%, MgO content is 23.54%, CaO content is 0.3%, SiO2 content is 0.25%, and Fe2O3 content is 0.23%.

[0042] The MAS-76 aluminum-magnesium spinel fine powder has a particle size of 325 mesh and a weight percentage of 6%. The chemical composition and content of the MAS-76 aluminum-magnesium spinel fine powder are as follows: Al2O3 content is 75.58%, MgO content is 23.54%, CaO content is 0.3%, SiO2 content is 0.25%, and Fe2O3 content is 0.23%.

[0043] The particle size of the Al2O3-MgO composite powder is 500 mesh; the chemical composition and content of the Al2O3-MgO composite powder are as follows: MgO content is 56%, Al2O3 content is 34.85%, SiO2 content is 9%, CaO content is 0.03%, and Fe2O3 content is 0.12%.

[0044] The content of MgO is 56%–66%, the content of Al2O3 is 25%–35%, the content of SiO2 is 8%–9%, ​​the content of CaO is 0.03%–0.05%, and the content of Fe2O3 is 0.09%–0.12%.

[0045] The chemical composition and content of the zircon fine powder are as follows: ZrO2 content 66.25%, SiO2 content 32.50%, TiO2 content 0.33%, Al2O3 content 0.37%, Fe2O3 content 0.16%, CaO content 0.05%, MgO content 0.02%, Na2O content 0.01%, and K2O content 0.01%; the particle size of the zircon fine powder is 325 mesh.

[0046] The chemical composition and content of the silicon metal powder are as follows: Si content is 98.6%, Fe content is 0.54%, Al content is 0.49%, and Ca content is 0.36%; the silicon metal powder is 98% silicon metal with a particle size of 325 mesh and a Si content of 98%.

[0047] The above-mentioned method for preparing the converter drain outlet with added recycled Al2O3-MgO composite powder includes the following steps:

[0048] Step 1: Preparation of co-milled powder: MAS-76 aluminum-magnesium spinel fine powder, regenerated Al2O3-MgO composite powder, zircon fine powder and metallic silicon powder are mixed evenly according to weight percentage to obtain co-milled powder;

[0049] Step 2, Granular Material Batching: Mix MAS-76 aluminum-magnesium spinel with a particle size of 5-3mm, MAS-76 aluminum-magnesium spinel with a particle size of 3-1mm, and MAS-76 aluminum-magnesium spinel with a particle size of 1-0mm evenly according to the weight percentage to obtain granular material.

[0050] Step 3, Mixing: After dry mixing the granules for 3-5 minutes, slowly add the thermosetting phenolic resin binder and wet mix for 6-8 minutes. Finally, add the co-milling powder and mix for 40-50 minutes before milling to obtain the mixture.

[0051] Step 4: Molding: Press the mixture into a semi-finished blank;

[0052] Step 5, Drying: After air-drying the billets naturally for 24 hours, place them in a tunnel natural gas drying kiln and dry them according to the set curve: the initial temperature upon entering the kiln is 20℃; in the first 0-3 hours, the temperature increases from 20℃ to 90℃; in the 3rd-6th hours, the temperature increases from 90℃ to 120℃; in the 6th-8th hours, the temperature increases from 120℃ to 150℃; in the 8th-10th hours, the temperature increases from 150℃ to 180℃; in the 10th-12th hours, the temperature increases from 180℃ to 210℃, and is held at this temperature for 12 hours; the total drying time is 24 hours.

[0053] Step Six: Shelling: Shell the blank obtained in Step Five. Rotate and apply fire clay to the outer wall of the sprue, then put on the steel shell. Invert the sprue into the fixture and press it to the set position. Remove the sprue. Press the shell and clean the fire clay overflowing from the upper part of the sprue. Remove the sprue from the fixture. After removing the sprue, place it with the upper opening facing down to clean the fire clay from the other opening. Perform the first inspection on the product. If the inspection is qualified, place the sprue with the larger end facing down on the frame. If the inspection is not qualified, adjust the limit block or use a tool to gently tap the iron shell to make it qualified.

[0054] Step 7, Shell Drying: After shelling, the product is naturally cured at room temperature for 4-8 hours before drying. Currently, a natural gas tunnel drying kiln is used for drying. The drying temperature curve is as follows: In the first 0-1 hour, the temperature rises from 30℃ to 80℃; in the second-3 hours, the temperature rises from 80℃ to 120℃; in the fourth-5 hours, the temperature rises from 120℃ to 150℃ and is held at this temperature for 8 hours; the total drying time is 13 hours.

[0055] Step 8, Packaging: After drying, remove from the kiln and let it air dry to room temperature. Check the dimensions and appearance according to the drawing requirements and appearance standards, and then pack it into boxes.

[0056] Example 2

[0057] In this embodiment, the converter outlet with recycled Al2O3-MgO composite powder is added. Its composition and weight percentages are as shown in Table 1. The chemical composition and content of the fine Al2O3-MgO composite powder are: MgO content 60.34%, Al2O3 content 31.25%, SiO2 content 8.27%, CaO content 0.04%, and Fe2O3 content 0.10%. The preparation method is the same as in Example 1.

[0058] Example 3

[0059] In this embodiment, the converter outlet with recycled Al2O3-MgO composite powder is added. Its composition and weight percentages are as shown in Table 1. The chemical composition and content of the fine Al2O3-MgO composite powder are: MgO content 63.15%, Al2O3 content 28.24%, SiO2 content 8.46%, CaO content 0.05%, and Fe2O3 content 0.12%. The preparation method is the same as in Example 1.

[0060] Example 4

[0061] In this embodiment, the converter outlet with recycled Al2O3-MgO composite powder is added. Its composition and weight percentages are as shown in Table 1. The chemical composition and content of the fine Al2O3-MgO composite powder are: MgO 65.95%, Al2O3 25.24%, SiO2 8.67%, CaO 0.05%, and Fe2O3 0.09%. The preparation method is the same as in Example 1.

[0062] Table 1. Particle type and percentage of ingredients used in each embodiment of the present invention.

[0063]

[0064]

[0065] The converter outlet with added recycled Al2O3-MgO composite powder was prepared according to the above examples.

[0066] Table 2. Physicochemical properties and average service life parameters of the converter drain outlets with added recycled Al2O3-MgO composite powder obtained in Examples 1-4 compared with existing aluminum-carbon converter drain outlets.

[0067]

[0068] Table 2 shows that the converter drain nozzle with recycled Al2O3-MgO composite powder of this invention was tested on a large converter. After the test, the drain nozzle with recycled Al2O3-MgO composite powder was compared with existing products in terms of hole expansion and cracking. The average service life was 22 cycles / piece, the hole expansion rate was 15 mm / piece on average, and the average erosion rate was 0.68 mm / cycle. Through batch use, the results were statistically compared with existing products. The average erosion rate of the converter drain nozzle with recycled Al2O3-MgO composite powder of this invention was ≤1 mm / cycle, which is lower than the erosion rate of existing aluminum-carbon products ≥3 mm / cycle. The hole expansion and internal condition of the drain nozzles that were disassembled after use were good, and no steel leakage, breakage, or cracking was found. Therefore, the converter drain nozzle with recycled Al2O3-MgO composite powder of this invention has excellent high temperature resistance, excellent thermal shock resistance, and slag corrosion resistance.

[0069] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A converter outlet with added Al2O3-MgO composite powder, characterized in that: Its raw materials include 60%-65% MAS-76 aluminum magnesium spinel and 35%-40% co-ground powder, the sum of the weight percentages of the two is 100%; plus 4% to 5% thermosetting phenolic resin binder of the total weight percentage; Of the 60%-65% MAS-76 aluminum-magnesium spinel, 15% is MAS-76 aluminum-magnesium spinel with a grain size of 5-3 mm, 30% is MAS-76 aluminum-magnesium spinel with a grain size of 3-1 mm, and 15%-20% is MAS-76 aluminum-magnesium spinel with a grain size of 1-0 mm. The co-milled powder comprises 6%–12% MAS-76 aluminum-magnesium spinel fine powder, 18%–28% Al2O3-MgO composite fine powder, 4%–5% zircon fine powder, and 1%–2% metallic silicon powder; the particle size of the MAS-76 aluminum-magnesium spinel fine powder is 325 mesh. The chemical composition and content of the Al2O3-MgO composite fine powder are as follows: MgO content is 56%–66%, Al2O3 content is 25%–35%, SiO2 content is 8%–9%, ​​CaO content is 0.03–0.05%, and Fe2O3 content is 0.09–0.12%. The Al2O3-MgO composite fine powder is obtained by recycling steel ladle slide plates used in steel plants, sorting them, sintering them at 1380℃ in an oxidizing atmosphere, and then grinding them in a ball mill after passing through a jaw crusher, hammer crusher, and iron removal.

2. The converter outlet with Al2O3-MgO composite powder added according to claim 1, characterized in that: The fine powder of the Al2O3-MgO composite powder has a particle size of 500 mesh.

3. The converter outlet with Al2O3-MgO composite powder added according to claim 1, characterized in that: The chemical composition and content of the MAS-76 aluminum magnesium spinel are as follows: Al2O3 content is 75.58%, MgO content is 23.54%, CaO content is 0.3%, SiO2 content is 0.25%, and Fe2O3 content is 0.23%.

4. The converter outlet with added Al2O3-MgO composite powder according to claim 3, characterized in that: The MAS-76 aluminum-magnesium spinel and MAS-76 aluminum-magnesium spinel fine powder are produced by industrial MAS-76 aluminum-magnesium spinel through a multi-stage homogenization process and sintering at a high temperature of over 1800℃ in an ultra-high temperature tunnel kiln.

5. The converter outlet with Al2O3-MgO composite powder added according to claim 1, characterized in that: The zircon fine powder has a particle size of 325 mesh, and its chemical composition and content are as follows: ZrO2 content 66.25%, SiO2 content 32.50%, TiO2 content 0.33%, Al2O3 content 0.37%, Fe2O3 content 0.16%, CaO content 0.05%, MgO content 0.02%, Na2O content 0.01%, and K2O content 0.01%.

6. The converter outlet with Al2O3-MgO composite powder added according to claim 1, characterized in that: The silicon metal powder has a particle size of 325 mesh, and its chemical composition and content are as follows: Si content is 98.6%, Fe content is 0.54%, Al content is 0.49%, and Ca content is 0.36%.

7. A method for preparing a converter outlet with added Al2O3-MgO composite powder according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Preparation of co-milled powder: MAS-76 aluminum-magnesium spinel fine powder, regenerated Al2O3-MgO composite powder, zircon fine powder and metallic silicon powder are mixed evenly according to weight percentage to obtain co-milled powder; Step 2, Granular Material Batching: Mix MAS-76 aluminum-magnesium spinel with a particle size of 5-3mm, MAS-76 aluminum-magnesium spinel with a particle size of 3-1mm, and MAS-76 aluminum-magnesium spinel with a particle size of 1-0mm evenly according to the weight percentage to obtain granular material. Step 3, Mixing: After dry mixing the granules for 3-5 minutes, slowly add the thermosetting phenolic resin binder and wet mix for 6-8 minutes. Finally, add the co-milling powder and mix for 40-50 minutes before milling to obtain the mixture. Step 4: Molding: Press the mixture into a semi-finished blank; Step 5, Drying: After air-drying the billets naturally for 24 hours, place them in a tunnel natural gas drying kiln and dry them according to the set curve: the initial temperature upon entering the kiln is 20℃; in the first 0-3 hours, the temperature increases from 20℃ to 90℃; in the 3rd-6th hours, the temperature increases from 90℃ to 120℃; in the 6th-8th hours, the temperature increases from 120℃ to 150℃; in the 8th-10th hours, the temperature increases from 150℃ to 180℃; in the 10th-12th hours, the temperature increases from 180℃ to 210℃, and is held at this temperature for 12 hours; the total drying time is 24 hours. Step 6, Shelling: Shell the blank obtained in Step 5, rotate and apply fire clay to the outer wall of the drain outlet, put on the steel shell, invert the drain outlet into the tooling, press it to the set position, and take out the drain outlet; press the shell, clean the fire clay overflowing from the upper part of the drain outlet, take out the tooling from the drain outlet, and after taking out the drain outlet, place it with the upper opening facing down to clean the fire clay of the other outlet. The product undergoes an initial inspection. If the product passes the inspection, the drain outlet is placed on the frame with the larger end facing down. If the product fails the inspection, the limit block is adjusted or the metal shell is gently tapped with a tool to make it pass the inspection. Step 7, Shell Drying: After shelling, the product is naturally cured at room temperature for 4-8 hours before drying. Currently, a natural gas tunnel drying kiln is used for drying. The drying temperature curve is as follows: In the first 0-1 hour, the temperature rises from 30℃ to 80℃; in the second-3 hours, the temperature rises from 80℃ to 120℃; in the fourth-5 hours, the temperature rises from 120℃ to 150℃ and is held at this temperature for 8 hours; the total drying time is 13 hours. Step 8, Packaging: After drying, remove from the kiln and let it air dry to room temperature. Check the dimensions and appearance according to the drawing requirements and appearance standards, and then pack it into boxes.

8. The method for preparing a converter outlet with added Al2O3-MgO composite powder according to claim 7, characterized in that: In step three, the granular material is added to a wet mill for dry mixing, and in step four, the mixture is pressed into shape on a 1200t electric screw press brick machine.

Images