A converter mouth sealing structure

Abstract

This utility model relates to the field of iron and steel smelting technology, specifically to a converter mouth sealing structure, comprising magnesia-carbon bricks. The magnesia-carbon bricks are arranged in a ring-like layer below the furnace mouth, in a top-to-bottom order, comprising a first layer of magnesia-carbon bricks, furnace cap magnesia-carbon bricks, furnace body magnesia-carbon bricks, molten pool magnesia-carbon bricks, and furnace bottom magnesia-carbon bricks. The first layer of magnesia-carbon bricks is positioned below the furnace mouth, and an expansion joint is formed between the first layer of magnesia-carbon bricks and the furnace mouth. The expansion joint is filled with ramming material, and extruded steel plates are inserted into the ramming material. The ramming material is sealed within the expansion joint by a steel strip. This utility model improves the stability of the ramming material by inserting extruded steel plates into the ramming material and using a steel strip to seal the ramming material in the expansion joint, preventing the ramming material and magnesia-carbon bricks from falling off during converter opening and tilting charging.

Description

Technical Field

[0001] This utility model relates to the field of iron and steel smelting technology, specifically to a converter furnace mouth sealing structure. Background Technology

[0002] The converter is a crucial steelmaking equipment in the iron and steel industry, primarily used to convert molten iron into molten steel, removing impurities and adjusting composition through methods such as oxygen blowing. The converter lining is a key thermal component that directly contacts high-temperature molten steel, slag, and furnace gases; its performance directly determines the converter's smelting efficiency, service life, and safety. Converter linings are mainly composed of basic refractories, including magnesia refractories, magnesia-calcium refractories, magnesia-chrome refractories, dolomite refractories, and other new types of basic refractories. Magnesia refractories, with magnesium oxide as their main component, are a class of basic refractories. Due to their outstanding resistance to alkaline slag corrosion, excellent atmosphere adaptability, and extremely high refractory limit, magnesia refractories have become the most widely used basic refractories.

[0003] Magnesia-carbon bricks are a type of magnesia refractory material made primarily from high-purity magnesia (MgO) and flake graphite, supplemented with antioxidants such as aluminum (Al), silicon (Si), magnesium (Mg), or boron nitride (BN), as well as binders such as phenolic resin and asphalt. The process involves mixing, molding, and high-temperature heat treatment. When magnesia-carbon bricks are used to line converter furnaces, their thermal expansion after start-up compresses the area above the converter mouth, causing the bricks below the mouth to crack and damaging the furnace mouth itself.

[0004] Existing technology typically leaves a 30-60mm expansion gap at the bottom of the converter opening and seals it with ramming material. After the converter is started, the magnesia-carbon bricks expand due to heat, compressing the ramming material and thus preventing direct pressure on the furnace opening, which could cause the magnesia-carbon bricks to crack and the furnace opening to be damaged. However, because the time between converter construction and start-up is short (usually less than 24 hours), the ramming material used to fill the expansion gap is difficult to dry and solidify effectively. During converter start-up, charging, and shaking, the ramming material at the furnace opening is prone to loosening and falling off. Especially in winter, the magnesia ramming material is easily frozen into lumps, making it even more likely to fall off during converter start-up and charging. This results in a large gap between the furnace opening and the magnesia-carbon bricks at the furnace cap, making it easy for the upper magnesia-carbon bricks to fall off and affecting the safe operation of the converter. Utility Model Content

[0005] To address the technical problem that ramming material at the converter opening is prone to falling off during the tilting and charging process, this utility model provides a converter opening sealing structure. By inserting extrusion steel plates into the ramming material and setting steel strips to seal the ramming material in the expansion joint, the stability of the ramming material is improved, preventing the ramming material and magnesia-carbon bricks from falling off during the tilting and charging process.

[0006] The technical solution of this utility model is as follows:

[0007] A converter mouth sealing structure includes magnesia-carbon bricks, which are arranged in a ring-shaped layer below the mouth. The ring-shaped layered magnesia-carbon bricks, arranged from top to bottom, include a first layer of magnesia-carbon bricks, a furnace cap magnesia-carbon brick, a furnace body magnesia-carbon brick, a molten pool magnesia-carbon brick, and a furnace bottom magnesia-carbon brick. The first layer of magnesia-carbon bricks is located below the mouth, and an expansion joint is provided between the first layer of magnesia-carbon bricks and the mouth. The expansion joint is filled with ramming material, and extruded steel plates are inserted into the ramming material. The ramming material is sealed in the expansion joint by steel strips.

[0008] The length of the first layer of magnesia-carbon bricks is 400-700mm. The length of the magnesia-carbon bricks refers to their length in the horizontal circular direction.

[0009] The ramming mix is ​​a carbon-magnesium ramming mix, which has strong resistance to erosion by molten steel and slag, and excellent high-temperature resistance, making it suitable for high-scouring areas such as the converter mouth and high-temperature zones of the furnace body. Because the carbon-magnesium ramming mix is ​​a plastic material, it can gradually sinter into a dense structure at high temperatures, filling the tiny gaps between the magnesia-carbon bricks and the furnace mouth, forming a seamless sealing layer, further preventing the leakage of molten steel and slag.

[0010] Furthermore, the height of the expansion joint is 30-60mm, corresponding to the height of the magnesia-carbon brick masonry in the converter body. When the height of the magnesia-carbon brick masonry in the converter body is 8-9m, the height of the expansion joint is 30-40mm; when the height of the magnesia-carbon brick masonry in the converter body is 9-10m, the height of the expansion joint is 40-50mm; and when the height of the magnesia-carbon brick masonry in the converter body is 10-11m, the height of the expansion joint is 50-60mm.

[0011] Furthermore, cardboard is placed between adjacent layers of magnesia-carbon bricks.

[0012] Furthermore, the height of the first layer of magnesia-carbon bricks is less than the height of the other layers. If the height of the expansion joint needs to be adjusted after each layer of magnesia-carbon bricks is laid, the height of the first layer of magnesia-carbon bricks can be reduced by cutting, ensuring that the height of the expansion joint between the first layer of magnesia-carbon bricks and the furnace opening is 30-60mm.

[0013] Furthermore, extrusion steel plates are inserted at intervals in the ramming mix. Preferably, one extrusion steel plate is inserted every 1 meter in the ramming mix. The extrusion steel plates can segment and locally extrude the uppermost layer of magnesia-carbon bricks, thus dividing and securing the ramming mix.

[0014] Furthermore, the extruded steel plate is an isosceles triangular steel plate with a thickness of 3-5mm. When the length of the uppermost magnesia-carbon brick is 400-500mm, the dimensions of the isosceles triangular steel plate are 300mm×300mm×420mm (leg length×leg length×base); when the length of the uppermost magnesia-carbon brick is 501-600mm, the dimensions of the isosceles triangular steel plate are 400mm×400mm×550mm; and when the length of the uppermost magnesia-carbon brick is 601-700mm, the dimensions of the isosceles triangular steel plate are 500mm×500mm×700mm.

[0015] Furthermore, the steel strip has a thickness of 1-3mm and a height of 100-200mm. The upper end of the steel strip is fixed to the furnace mouth, preferably by welding, and the lower end of the steel strip is tightly fitted to the side of the first layer of magnesia-carbon bricks facing inwards from the converter. The steel strip is an arc-shaped steel strip adapted to the inner opening of the converter mouth, and the arc-shaped steel strips are connected end to end along the inner opening of the converter mouth to form a complete ring structure.

[0016] Furthermore, cardboard with a thickness of 1 mm is placed between adjacent layers of magnesia-carbon bricks in the furnace body. The converter body can be divided into a cap section, a body section, and a bottom section. The first layer of magnesia-carbon bricks and the cap magnesia-carbon bricks are laid in the cap section of the converter, while the body magnesia-carbon bricks are laid in the body section. During the magnesia-carbon brick laying process, the expansion joints can be controlled by placing cardboard between adjacent layers of magnesia-carbon bricks in the body. A single layer of cardboard is added between adjacent layers of magnesia-carbon bricks in the body. When the height of the magnesia-carbon bricks in the converter body is 8-9m, the number of cardboard sheets added is 10-20 sheets; when the height of the magnesia-carbon bricks in the converter body is 9-10m, the number of cardboard sheets added is 21-30 sheets; and when the height of the magnesia-carbon bricks in the converter body is 10-11m, the number of cardboard sheets added is 31-40 sheets.

[0017] The beneficial effects of this utility model are as follows:

[0018] This utility model provides a converter furnace opening sealing structure. An expansion joint is set between the first layer of magnesia-carbon bricks and the furnace opening to provide space for the thermal expansion and contraction of the magnesia-carbon bricks, avoiding cracking of the magnesia-carbon bricks or damage to the furnace opening structure due to stress concentration. The expansion joint is filled with ramming material, and the height of the expansion joint matches the height of the magnesia-carbon bricks in the furnace lining material, allowing it to expand and contract synchronously with temperature changes, preventing cracks caused by thermal expansion of the magnesia-carbon bricks. Extrusion steel plates are inserted into the ramming material, which can enhance the structural strength of the ramming material and prevent it from collapsing or peeling off under high temperature due to stress (such as molten steel impact or mechanical vibration). The extrusion steel plates also serve to divide the ramming material, preventing damaged magnesia-carbon bricks and ramming material in some areas from affecting undamaged magnesia-carbon bricks and ramming material in other areas. Steel strips are used to seal the ramming material in the expansion joint. The steel strips can completely seal the ramming material in the expansion joint, which can prevent the ramming material and the first layer of magnesia-carbon bricks from falling off during the furnace opening process, prevent molten steel and slag from seeping into the gap, and avoid safety hazards such as "steel penetration". Attached Figure Description

[0019] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the converter opening sealing structure in Example 1.

[0021] Figure 2 This is a schematic diagram of the converter opening sealing structure in Example 2.

[0022] Figure 3 This is a schematic diagram of the converter opening sealing structure in Example 3.

[0023] In the diagram, 1-furnace opening, 2-ramming material, 3-first layer of magnesia-carbon bricks, 4-furnace cap magnesia-carbon bricks, 5-furnace body magnesia-carbon bricks, 6-extruded steel plate, 7-steel strip, 8-cardboard. Detailed Implementation

[0024] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0025] Example 1

[0026] A converter inlet sealing structure with a furnace body height of 8700mm, such as... Figure 1 As shown, the furnace includes magnesia-carbon bricks, which are laid in a ring-like layer below the furnace opening 1. Following a top-to-bottom order, the ring-like layered magnesia-carbon bricks include a first layer of magnesia-carbon bricks 3, a furnace cap magnesia-carbon brick 4, a furnace body magnesia-carbon brick 5, a molten pool magnesia-carbon brick, and a furnace bottom magnesia-carbon brick (the molten pool and furnace bottom magnesia-carbon bricks are not shown in the figure). The first layer of magnesia-carbon bricks 3 and the furnace cap magnesia-carbon brick 4 are laid in the furnace cap section of the converter. The first layer of magnesia-carbon bricks 3 is the uppermost layer of magnesia-carbon bricks in the furnace cap section. The furnace body magnesia-carbon bricks 5 are laid in the straight section of the converter's furnace body. The length of the first layer of magnesia-carbon bricks 3 is 450 mm, referring to the length of the magnesia-carbon brick in the horizontal circular direction. An expansion joint with a height of 35 mm is provided between the first layer of magnesia-carbon bricks 3 and the furnace opening 1. The expansion joint is filled with ramming material 2, which is a carbon-containing magnesia ramming material. In this carbon-containing magnesia ramming material, the mass percentage of MgO is not less than 87%, and the mass percentage of C is not less than 3%. In the ramming mix 2, an extruded steel plate is inserted every 1m along the horizontal circular direction. The extruded steel plate is an isosceles triangular steel plate with a thickness of 3mm and a size of 300mm×300mm×420mm (leg length×leg length×base). The ramming mix 2 is sealed in the expansion joint by a steel strip 7 with a thickness of 2mm and a height of 100mm. The upper end of the steel strip 7 is welded to the furnace opening 1, and the lower end of the steel strip 7 is tightly fitted to the side of the first layer of magnesia-carbon bricks 3 facing the inside of the converter. The steel strip 7 is an arc-shaped steel strip adapted to the inner opening of the furnace opening 1, with a length of 2m. The arc-shaped steel strips are connected end to end along the inner opening of the furnace opening 1 to form a complete ring structure.

[0027] Example 2

[0028] A converter inlet sealing structure with a furnace body height of 9350mm, such as... Figure 2As shown, the furnace includes magnesia-carbon bricks, which are laid in a ring-like layer below the furnace opening 1. Following a top-to-bottom order, the ring-like layered magnesia-carbon bricks include a first layer of magnesia-carbon bricks 3, a furnace cap magnesia-carbon brick 4, a furnace body magnesia-carbon brick 5, a molten pool magnesia-carbon brick, and a furnace bottom magnesia-carbon brick (the molten pool and furnace bottom magnesia-carbon bricks are not shown in the diagram). The first layer of magnesia-carbon bricks 3 and the furnace cap magnesia-carbon brick 4 are laid in the furnace cap section of the converter. The first layer of magnesia-carbon bricks 3 is the uppermost layer of magnesia-carbon bricks in the furnace cap section. The furnace body magnesia-carbon bricks 5 are laid in the straight section of the converter's furnace body. The length of the first layer of magnesia-carbon bricks 3 is 550 mm. The length of the magnesia-carbon brick refers to its length in the horizontal circular direction. During the magnesia-carbon brick laying process, a single layer of cardboard 8, 1 mm thick, is added between adjacent layers of furnace body magnesia-carbon bricks 5. The number of cardboard sheets 8 added is 16. An expansion joint with a height of 45mm is set between the first layer of magnesia-carbon bricks 3 and the furnace opening 1. The expansion joint is filled with ramming material 2, which is a carbon-magnesia ramming material. In the carbon-magnesia ramming material, the mass percentage of MgO is not less than 87%, and the mass percentage of C is not less than 3%. In the ramming material 2, an extruded steel plate is inserted every 1m in the horizontal circular direction. The extruded steel plate is an isosceles triangular steel plate with a thickness of 3mm and a size of 400mm×400mm×550mm (leg length×leg length×base). The ramming material 2 is sealed in the expansion joint by a steel strip 7 with a thickness of 2mm and a height of 150mm. The upper end of the steel strip 7 is welded to the furnace opening 1, and the lower end of the steel strip 7 is tightly attached to the side of the first layer of magnesia-carbon bricks 3 facing the inside of the converter. The steel strip 7 is an arc-shaped steel strip that is adapted to the inner opening of the furnace opening 1. The length of the arc-shaped steel strip is 2m. Each arc-shaped steel strip is connected end to end along the inner opening of the furnace opening 1 to form a complete ring structure.

[0029] Example 3

[0030] A converter inlet sealing structure with a furnace body height of 10000mm, such as... Figure 3As shown, the converter includes magnesia-carbon bricks, which are laid in a ring-like layer below the furnace opening 1. Following a top-to-bottom order, the ring-like layered magnesia-carbon bricks include a first layer of magnesia-carbon bricks 3, a furnace cap magnesia-carbon brick 4, a furnace body magnesia-carbon brick 5, a molten pool magnesia-carbon brick, and a furnace bottom magnesia-carbon brick (the molten pool and furnace bottom magnesia-carbon bricks are not shown in the figure). The first layer of magnesia-carbon bricks 3 and the furnace cap magnesia-carbon brick 4 are laid in the furnace cap section of the converter. The first layer of magnesia-carbon bricks 3 is the uppermost layer of magnesia-carbon bricks in the furnace cap section. The furnace body magnesia-carbon bricks 5 are laid in the straight section of the converter body. The length of the first layer of magnesia-carbon bricks 3 is 650 mm, referring to the length of the magnesia-carbon brick in the horizontal circular direction. An expansion joint is provided between the first layer of magnesia-carbon bricks 3 and the furnace opening 1. The height of the first layer of magnesia-carbon bricks 3 is reduced by cutting, making the height of the first layer of magnesia-carbon bricks 3 less than the height of the furnace cap magnesia-carbon brick 4 and the furnace body magnesia-carbon brick 5. After the magnesia-carbon bricks are laid, the height of the expansion joint is less than 50mm. The height of the first layer of magnesia-carbon bricks 3 is reduced by cutting to ensure the expansion joint height is 55mm. The expansion joint is filled with ramming material 2, which is a carbon-magnesia ramming material. In this material, the mass percentage of MgO is not less than 87%, and the mass percentage of C is not less than 3%. In the ramming material 2, an extruded steel plate is inserted every 1m in the horizontal circular direction. The extruded steel plate is an isosceles triangular steel plate with a thickness of 4mm and dimensions of 500mm × 500mm × 700mm (leg length × leg length × base). The ramming material 2 is sealed within the expansion joint by a steel strip 7 with a thickness of 2mm and a height of 150mm. The upper end of the steel strip 7 is welded to the furnace opening 1, and the lower end of the steel strip 7 is tightly fitted to the side of the first layer of magnesia-carbon bricks 3 facing inwards from the converter. The steel strip 7 is an arc-shaped steel strip that is adapted to the inner opening of the furnace opening 1. The length of the arc-shaped steel strip is 2.5m. Each arc-shaped steel strip is connected end to end along the inner opening of the furnace opening 1 to form a complete ring structure.

[0031] Comparative Example 1

[0032] A converter mouth sealing structure with a furnace height of 9000mm includes magnesia-carbon bricks. These magnesia-carbon bricks are laid in a ring-like layer below the furnace mouth. From top to bottom, the ring-like layered magnesia-carbon bricks include a first layer, a furnace cap magnesia-carbon brick, a furnace body magnesia-carbon brick, a molten pool magnesia-carbon brick, and a furnace bottom magnesia-carbon brick (the molten pool and furnace bottom magnesia-carbon bricks are not shown in the figure). The first layer and the furnace cap magnesia-carbon brick are laid in the furnace cap section of the converter, while the furnace body magnesia-carbon brick is laid in the straight section of the converter body. The length of the first layer of magnesia-carbon bricks is 470mm, referring to its length in the horizontal circular direction. An expansion joint with a height of 35mm is provided between the first layer of magnesia-carbon bricks and the furnace mouth. The expansion joint is filled with ramming material, which is a carbonaceous magnesia ramming material. In this carbonaceous magnesia ramming material, the mass percentage of MgO is not less than 87%, and the mass percentage of C is not less than 3%.

[0033] Example 1: Directly tilt the converter forward at approximately 30° and add 5 tons of already ignited coke and 2 tons of tree roots. Then, verticalize the converter, lower the oxygen lance, and use a 5000-9000m... 3 The furnace was dried using a low oxygen flow rate of / h for 2.5 hours. During the drying process, the ramming material from Example 1 was uniformly dried and solidified under the protection of the steel belt. After drying, the furnace was tilted forward 30-50°. During the addition of molten iron and scrap steel, the ramming material at the bottom of the furnace mouth remained intact under the protection of the steel belt. The first layer of magnesia-carbon bricks and the magnesia-carbon bricks at the furnace cap remained firmly secured by the extrusion steel plates without any loosening. During production, the ramming material at the bottom of the furnace mouth, the first layer of magnesia-carbon bricks, and the magnesia-carbon bricks at the furnace cap remained firm and intact. After the furnace was started and production began in Example 1, the furnace mouth bricks were neat, and there was no detachment of the ramming material.

[0034] Comparative Example 1: The converter was tilted forward at approximately 30°, and 6 tons of already ignited coke and 2 tons of tree roots were added. The converter was then verticalized, the oxygen lance lowered, and a flow rate of 6000-10000 m³ / h was adopted. 3 The furnace was dried using a low oxygen flow rate of / h for 3 hours. During the drying process, the surface of the ramming material in Comparative Example 1 dried, clumped, and cracked. After drying, during the addition of molten iron and scrap steel while tilting the furnace forward 30-50°, some of the ramming material at the bottom of the furnace opening fell off, creating gaps. After the converter in Comparative Example 1 was opened, the ramming material fell off, and the first layer of magnesia-carbon bricks became loose. During production, the first layer of magnesia-carbon bricks and the magnesia-carbon bricks in the furnace cap become loose, posing a risk of falling off and affecting converter production. Regular maintenance with filling material is necessary to repair the loose magnesia-carbon bricks at the furnace opening and the gaps at the bottom of the furnace opening.

[0035] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A converter mouth sealing structure comprising magnesia carbon bricks which are annularly layered and built under the mouth, characterized in that, In a top-to-bottom order, the ring-shaped layered magnesia-carbon bricks include the first layer of magnesia-carbon bricks, the furnace cap magnesia-carbon bricks, the furnace body magnesia-carbon bricks, the molten pool magnesia-carbon bricks, and the furnace bottom magnesia-carbon bricks. The first layer of magnesia-carbon bricks is placed below the furnace opening, and an expansion joint is set between the first layer of magnesia-carbon bricks and the furnace opening. The expansion joint is filled with ramming material, and extruded steel plates are inserted into the ramming material. The ramming material is sealed in the expansion joint by steel strips.

2. A converter mouth closure structure as claimed in claim 1, wherein The height of the expansion joint is 30-60mm.

3. A converter mouth closure structure as claimed in claim 2, wherein Cardboard is placed between adjacent layers of magnesia-carbon bricks.

4. A converter mouth closure structure as claimed in claim 2, wherein The height of the first layer of magnesia-carbon bricks is less than the height of the other layers of magnesia-carbon bricks.

5. A converter mouth closure structure as claimed in claim 1, wherein Extrusion steel plates are inserted at intervals in the ramming mix.

6. The converter mouth sealing structure as described in claim 1, characterized in that, The extruded steel plate is an isosceles triangular steel plate with a thickness of 3-5mm.

7. The converter mouth sealing structure as described in claim 1, characterized in that, The thickness of the steel strip is 1-3mm, and the height of the steel strip is 100-200mm.

8. The converter mouth sealing structure as described in claim 3, characterized in that, Cardboard is placed between adjacent layers of magnesia-carbon bricks in the furnace body.

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