A scrap utilization device and method for an RH refining furnace

Abstract

The application belongs to the technical field of scrap steel utilization of RH refining furnace, and particularly relates to a scrap steel utilization device and method of RH refining furnace. The scrap steel utilization device of the RH refining furnace comprises a vacuum tank and a plugging device. The plugging device comprises a net plugging device, an air source, a lifting device and a connector. The net plugging device comprises a framework, a hanging rod, a net body and a vertical pipe. The net body is fixed on the framework and forms a disc-shaped structure. The framework is uniformly provided with a plurality of sliding cavities along the radial direction of the framework. The hanging rod is slidingly installed in the sliding cavities. The hanging rod can slide along the sliding cavities under the air pressure provided by the air source and extend out of the framework, so that the net plugging device is hung on the upper edge of the immersion pipe and blocks the immersion pipe. The application realizes the preheating and utilization of scrap steel by the RH refining furnace, and does not need to additionally increase a preheating device, so that the investment in site and equipment is low, and the economic benefit is high.

Description

Technical Field

[0001] This invention belongs to the field of scrap steel utilization technology for RH refining furnaces, specifically relating to a scrap steel utilization device and method for RH refining furnaces. Background Technology

[0002] The RH refining furnace is a secondary refining process equipment used to produce high-quality steel. The entire metallurgical reaction of the molten steel takes place in a vacuum tank lined with refractory lining. The lower part of the vacuum tank consists of two refractory-lined immersion tubes, and the upper part is equipped with a hot-bent tube. The extracted gas passes through the hot-bent tube, a gas cooler, and a vacuum pump system to be discharged outside the plant. Before steel treatment, the immersion tubes are immersed in the molten steel in the ladle. When the vacuum tank is evacuated, the atmospheric pressure on the surface of the molten steel forces it to flow from the immersion tubes into the vacuum tank. Two immersion tubes connected to the vacuum tank are a riser and a downcomer. Because the riser continuously blows argon into the molten steel, a higher static pressure difference is created relative to the downcomer, which does not blow argon. This causes the molten steel to enter through the riser and flow through the lower part of the vacuum tank to the downcomer, thus continuously circulating. Under vacuum conditions, gases such as argon, hydrogen, and carbon monoxide in the molten steel flowing through the vacuum tank are extracted during the steel circulation process. Meanwhile, the molten steel entering the vacuum tank undergoes a series of metallurgical reactions, such as carbon-oxygen reactions; this cycle of degassing and refining purifies the molten steel.

[0003] In the steel industry, the ratio of molten iron to scrap steel has always been a key issue. Using scrap steel can reduce iron ore mining, save raw coal, and reduce emissions of CO2 and large amounts of wastewater, exhaust gas, and solid waste. Therefore, increasing the proportion of scrap steel added is an effective way to reduce costs, save energy, and reduce environmental pollution. Although scrap steel is a raw material for converter smelting, as a self-heating metallurgical reactor, adding too much scrap steel can lead to insufficient tapping temperature, limiting the converter's ability to consume scrap steel under conventional smelting processes. Therefore, effectively utilizing scrap steel in the refining process is of great significance for reducing costs, saving energy, and reducing environmental pollution.

[0004] Due to the structural characteristics of the vacuum chamber, RH refining furnaces cannot utilize scrap steel. Furthermore, existing technologies require additional baking devices for preheating scrap steel in refining furnaces. For example, CN110701913A discloses a scrap steel preheating and feeding device for refining furnaces, which necessitates the addition of a preheating furnace, resulting in significant investment in space and equipment. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a scrap steel utilization device and method for an RH refining furnace. By sealing the immersion tube with a mesh sealer, the vacuum tank and top-blown oxygen lance of the RH refining furnace can be used as scrap steel preheating equipment. In the next heat of steelmaking, the circulation of the vacuum tank allows the preheated scrap steel to melt into the molten steel. This not only realizes the preheating and utilization of scrap steel in the RH refining furnace, but also eliminates the need for additional preheating equipment, resulting in low site and equipment investment and high economic benefits.

[0006] This invention provides a scrap steel utilization device for an RH refining furnace, comprising a vacuum tank and a sealing device. The vacuum tank has an impregnation tube at its bottom and a feeding chute on its upper surface. A top-blown oxygen lance is located within the vacuum tank. The sealing device includes a mesh sealer, a gas source, a lifting device, and a connector. The mesh sealer comprises a frame, a hanging rod, a mesh body, and a vertical pipe. The mesh body is fixed to the frame and forms a disc-shaped structure. Multiple sliding cavities are evenly distributed along the radial direction of the frame. The hanging rod is slidably installed within the sliding cavities. The upper end of the vertical pipe is fixedly connected to the frame, and its upper port communicates with each sliding cavity. The connector is fixedly installed on the lifting device. The connector has a connecting gas channel inside. The lower end of the vertical pipe is detachably connected to the connector, and its lower port communicates with the connecting gas channel, which is connected to the gas source. The hanging rod can slide along the sliding cavities under the gas pressure provided by the gas source and extends beyond the frame, allowing the mesh sealer to hang on the upper edge of the impregnation tube and seal it.

[0007] Furthermore, the number of the hanging poles is ≥4.

[0008] Furthermore, the outer end of the gantry is provided with anchor claws. Using this technical solution, the anchor claws can increase the connection force between the gantry and the upper edge of the impregnation tube, allowing the mesh sealer to be more firmly connected to the upper edge of the impregnation tube.

[0009] Furthermore, the skeleton includes an annular portion and a radial portion, the radial portion being arranged radially along the annular portion and fixedly connected to the annular portion, and the sliding cavity being disposed within the radial portion.

[0010] Furthermore, a limiting block is provided at the inner end of the hanging rod, and the limiting block is slidably engaged with the sliding cavity; a limiting hollow bolt is provided at the outer port of the sliding cavity, and the limiting hollow bolt is threadedly connected to the frame, the inner diameter of the limiting hollow bolt being smaller than the outer diameter of the limiting block. Using this technical solution, the cooperation of the limiting block and the limiting hollow bolt can prevent the hanging rod from detaching from the frame.

[0011] Furthermore, the gas supplied by the gas source is air or nitrogen, and the output pressure of the gas source is 0.8 to 1.2 MPa.

[0012] Furthermore, the lifting device is the spray gun lifting device on the impregnation tube spraying trolley. The impregnation tube spraying trolley is an essential piece of equipment at the RH refining furnace site. By using the spray gun lifting device on the impregnation tube spraying trolley to lift the mesh sealer, no additional equipment investment is required.

[0013] Furthermore, the frame, hanging poles, and netting are all made of 45# steel or 316 stainless steel.

[0014] Furthermore, the mesh size is 2-4 cm.

[0015] The present invention also provides a method for utilizing scrap steel using the scrap steel utilization device of the above-mentioned RH refining furnace, comprising the following steps:

[0016] After the previous batch of molten steel is smelted in the S1 and RH refining furnaces, the ladle car transports the ladle away from below the immersion tube, and the immersion tube is sprayed for maintenance.

[0017] S2. Fix the vertical tube to the connector. Insert the mesh sealer into the impregnation tube using the lifting device and lift it until the hanging rod is above the upper edge of the impregnation tube. Start the air source. Under the action of air pressure, the hanging rod slides along the sliding cavity and extends out of the frame so that the mesh sealer hangs on the upper edge of the impregnation tube and seals the impregnation tube.

[0018] S3. Disconnect the vertical tube from the connector, and the lifting device will fall and move away from under the immersion tube;

[0019] S4. The scrap steel is added to the vacuum tank through the feeding chute, and the top-blown oxygen lance is used to bake the refractory lining and the scrap steel.

[0020] S5. During the smelting of the next batch of molten steel, scrap steel and mesh sealer melt into the molten steel under the circulation of the vacuum tank.

[0021] By means of the above technical solution, the technical solution provided by the present invention has at least the following advantages: (1) By sealing the immersion tube with a mesh sealer, the vacuum tank and top-blown oxygen lance of the RH refining furnace can be used as equipment for preheating scrap steel. In the next heat of steel smelting, the circulation of the vacuum tank is used to melt the preheated scrap steel into the molten steel. This not only realizes the preheating and utilization of scrap steel in the RH refining furnace, but also eliminates the need for additional preheating equipment. The investment in site and equipment is low and the economic benefits are high. (2) During the preheating of scrap steel, the mesh sealer supports the scrap steel through the mesh body. Under its own pressure and the high-pressure nitrogen in the vacuum tank, the flame of the top-blown oxygen lance can pass through the gaps in the scrap steel to the bottom of the scrap steel. Therefore, the heating is more uniform and the preheating effect is better. (3) The baking of the refractory lining by the top-blown oxygen lance is a necessary operation during the production interval of the RH furnace. Its function is to ensure that the refractory lining is maintained at a high temperature to reduce the temperature drop of the molten steel during the smelting process. During this process, a large amount of heat generated by the top-blown oxygen lance will be discharged from the immersion tube, resulting in a great waste of energy. This invention preheats scrap steel while baking the refractory lining with the top-blown oxygen lance, effectively utilizing the heat generated during the baking process of the refractory lining, thus achieving energy saving and consumption reduction. (4) During the production interval of the RH refining furnace, preheating scrap steel while baking the refractory lining with the top-blown oxygen lance has minimal impact on the smelting process and maintains the original production rhythm of the RH refining process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the scrap steel utilization device of the RH refining furnace in Example 1.

[0023] Figure 2 This is a schematic diagram of the sealing device in Example 1.

[0024] Figure 3 This is a main cross-sectional view of the mesh sealer in Example 1.

[0025] Figure 4 This is a reference diagram showing the usage status of the mesh sealer in Example 1.

[0026] Among them: 1-vacuum tank, 2-impregnation tube, 3-feeding chute, 4-top-blown oxygen lance, 5-net sealer, 6-air source, 7-lifting device, 8-connector, 9-hanging rod, 10-net body, 11-vertical tube, 12-sliding cavity, 13-connecting air passage, 14-anchor claw, 15-ring part, 16-radial part, 17-limiting block, 18-limiting hollow bolt, 19-impregnation tube spraying trolley, 20-scrap steel. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0028] Example 1

[0029] Figures 1-4 Embodiment 1 of the present invention is shown.

[0030] like Figure 1 As shown, a scrap steel utilization device for an RH refining furnace includes a vacuum tank 1 and a sealing device.

[0031] The vacuum tank 1 is a vacuum tank for a 120-ton RH refining furnace. The bottom of the vacuum tank 1 is provided with two impregnation tubes 2 with refractory linings. The inner radius of the impregnation tubes 2 is about 240cm. The vacuum tank 1 is provided with a feeding chute 3 and a top-blown oxygen lance 4.

[0032] The sealing device includes a mesh sealer 5, an air source 6, a lifting device 7, and a connector 8.

[0033] The mesh sealing device 5 includes a frame, hanging rods 9, a mesh body 10, and a vertical pipe 11. The frame, hanging rods 9, and mesh body 10 are all made of high-temperature resistant steel; in this embodiment, 45# steel is used, which, after melting, will not introduce impurities into the molten steel. The mesh body 10 has a 3cm aperture.

[0034] The mesh 10 is fixed to the frame and forms a disc-shaped structure. The radius of the mesh is 5-8 cm smaller than the radius of the impregnation tube to prevent the scrap steel 20 from leaking out. In this embodiment, the radius of the mesh is approximately 235 cm. Figure 4 As shown, the skeleton includes an annular portion 15 and a radial portion 16. Eight radial portions 16 are evenly distributed along the radial direction of the annular portion 15, and the radial portions 16 are fixedly connected to the annular portion 15.

[0035] A sliding cavity 12 is provided within the radial portion 16, and the hanging rod 9 is slidably installed within the sliding cavity 12. Figure 3As shown, the inner end of the hanging rod 9 is provided with a limiting block 17, which slides in conjunction with the sliding cavity 12; the outer port of the sliding cavity 12 is provided with a limiting hollow bolt 18, which is threaded to the frame, and the inner diameter of the limiting hollow bolt 18 is smaller than the outer diameter of the limiting block 17. The cooperation of the limiting block 17 and the limiting hollow bolt 18 prevents the hanging rod 9 from detaching from the frame.

[0036] The upper end of the vertical tube 11 is fixedly connected to the inner ends of the eight radial portions 16, and the upper port of the vertical tube 11 is connected to each sliding cavity 12 respectively.

[0037] Specifically, such as Figure 1 , Figure 2 As shown, the lifting device 7 in this embodiment is the spray gun lifting device on the impregnation tube spraying trolley 19, and the connector is welded to the inner spray gun. The impregnation tube spraying trolley 19 is an essential piece of equipment on the RH refining furnace site. The mesh sealer 5 is lifted using the spray gun lifting device on the impregnation tube spraying trolley 19, eliminating the need for additional equipment investment. The impregnation tube spraying trolley 19 is prior art; reference can be made to the single-spray gun structure vacuum circulating refining furnace impregnation tube spraying machine disclosed in CN201225828.

[0038] The connector 8 is fixedly mounted on the lifting device 7, and the connector 8 has a connecting air passage 13 inside. The lower end of the vertical tube 11 is detachably connected to the connector 8 and its lower port communicates with the connecting air passage 13. Specifically, in this embodiment, the vertical tube 11 inserted into the connecting air passage 13 is fixed to the connector 8 by fastening bolts.

[0039] The gas source 6 is connected to the connecting airway 13. The gas provided by the gas source 6 is air or nitrogen, and the output pressure of the gas source 6 is 0.8 to 1.2 MPa.

[0040] like Figure 1 , Figure 4 As shown, the hanging rod 9 can slide along the sliding cavity 12 under the air pressure provided by the air source 6 and extend outside the frame so that the mesh sealer 5 hangs on the upper edge of the impregnation tube 2 and seals the impregnation tube 2.

[0041] In order to increase the connection force between the hanging rod 9 and the upper edge of the impregnation tube 2, so that the mesh sealer 5 can be more firmly connected to the upper edge of the impregnation tube 2, the outer end of the hanging rod 9 is provided with an anchor claw 14.

[0042] This embodiment also provides a method for utilizing scrap steel using the scrap steel utilization device of the above-mentioned RH refining furnace, including the following steps:

[0043] After the previous batch of molten steel is smelted in the S1 and RH refining furnaces, the ladle car transports the ladle away from below the immersion tube 2, and the immersion tube 2 is sprayed and maintained by the immersion tube spraying trolley 19.

[0044] S2. Securely connect the vertical tube 11 to the connector 8. Insert the mesh sealer 5 into the impregnation tube 2 using the lifting device 7 and lift it until the hanging rod 9 is above the upper edge of the impregnation tube 2. Activate the air source 6. Under air pressure, the hanging rod 9 slides along the sliding cavity 12 and extends outside the frame. Figure 1 As shown, the hanging rod 9 is placed on the upper edge of the impregnation tube 2 so that the mesh sealer 5 is hung on the upper edge of the impregnation tube 2 and seals the impregnation tube 2.

[0045] S3. Disconnect the vertical tube 11 from the connector 8, and the lifting device 7 falls and moves away from below the immersion tube 2.

[0046] S4. Scrap steel 20 is added to vacuum tank 1 through feeding chute 3, and top-blown oxygen lance 4 is used to bake the refractory lining and scrap steel 20.

[0047] The baking of the refractory linings by the top-blown oxygen lance is a necessary operation during the production interval of the RH furnace. Its function is to ensure that the refractory linings are maintained at a high temperature to reduce the temperature drop of the molten steel during the smelting process.

[0048] S5. After the next batch of molten steel enters the station, the baking is stopped and the smelting of the next batch of molten steel begins. During the smelting of the next batch of molten steel, scrap steel 20 and mesh sealer 5 are melted into the molten steel under the circulation of the vacuum tank.

[0049] By means of the above technical solution, the technical solution provided in this embodiment has at least the following advantages: (1) By sealing the impregnation tube 2 with the mesh sealer 5, the vacuum tank 1 and the top-blown oxygen lance 4 of the RH refining furnace can be used as equipment for preheating scrap steel. In the next heat of steel smelting process, the circulation of the vacuum tank 1 is used to melt the preheated scrap steel 20 into the molten steel. This not only realizes the preheating and utilization of scrap steel 20 by the RH refining furnace, but also eliminates the need for additional preheating equipment. The investment in site and equipment is low and the economic benefits are high. (2) During the preheating process of scrap steel 20, the mesh sealer 5 supports the scrap steel 20 through the mesh body 10. Under its own pressure and the high-pressure nitrogen purging in the vacuum tank 1, the flame of the top-blown oxygen lance 4 can pass through the gap of the scrap steel 20 to the bottom of the scrap steel 20. Therefore, the heating is more uniform and the preheating effect is better. (3) The baking of the refractory lining by the top-blown oxygen lance 4 is a necessary operation during the production interval of the RH furnace. Its function is to ensure that the refractory lining is maintained at a higher temperature to reduce the temperature drop of the molten steel during the smelting process. During this process, a large amount of heat generated by the top-blown oxygen lance 4 is discharged from the impregnation tube 2, resulting in a great waste of energy. The present invention preheats the scrap steel 20 while the top-blown oxygen lance 4 bakes the refractory lining, effectively utilizing the heat generated during the baking process of the refractory lining, and has the effect of energy saving and consumption reduction. (4) During the production interval of the RH refining furnace, the scrap steel 20 is preheated while the top-blown oxygen lance 4 bakes the refractory lining, which has minimal impact on the smelting process and maintains the original production rhythm of the RH refining process.

[0050] The above description is merely a specific embodiment of this disclosure, but the protection scope of this disclosure is not limited thereto. Any changes, substitutions or combinations that can be easily conceived by those skilled in the art within the technical scope disclosed in this disclosure or under the ideas disclosed in this disclosure should be covered within the protection scope of this disclosure.

Claims

1. A scrap steel utilization device for an RH refining furnace, comprising a vacuum tank (1), wherein an impregnation pipe (2) is provided at the bottom of the vacuum tank (1), a feeding chute (3) is provided on the vacuum tank (1), and a top-blown oxygen lance (4) is provided inside the vacuum tank (1), characterized in that, It also includes a sealing device, which includes a mesh sealer (5), an air source (6), a lifting device (7), and a connector (8); the mesh sealer (5) includes a frame, a hanging rod (9), a mesh body (10), and a vertical pipe (11); the mesh body (10) is fixed on the frame and forms a disc-shaped structure; the frame has multiple sliding cavities (12) evenly distributed along the radial direction of the frame; the hanging rod (9) is slidably installed in the sliding cavity (12); the upper end of the vertical pipe (11) is fixedly connected to the frame and its upper port is respectively connected to each sliding cavity (6). 12) Connecting; the connector (8) is fixedly installed on the lifting device (7), the connector (8) is provided with a connecting air passage (13), the lower end of the vertical tube (11) is detachably connected to the connector (8) and its lower port is connected to the connecting air passage (13), the connecting air passage (13) is connected to the air source (6); the hanging rod (9) can slide along the sliding cavity (12) under the air pressure provided by the air source (6) and extend out of the frame so that the mesh sealer (5) hangs on the upper edge of the impregnation tube (2) and seals the impregnation tube (2).

2. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The number of the hanging poles (9) is ≥4.

3. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The outer end of the gantry (9) is provided with an anchor claw (14).

4. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The skeleton includes an annular portion (15) and a radial portion (16). The radial portion (16) is arranged radially along the annular portion (15) and fixedly connected to the annular portion (15). The sliding cavity (12) is arranged inside the radial portion (16).

5. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The inner end of the hanging rod (9) is provided with a limiting block (17), which is slidably engaged with the sliding cavity (12); the outer port of the sliding cavity (12) is provided with a limiting hollow bolt (18), which is threaded to the skeleton, and the inner diameter of the limiting hollow bolt (18) is smaller than the outer diameter of the limiting block (17).

6. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The gas supplied by the gas source (6) is air or nitrogen, and the output pressure of the gas source (6) is 0.8 to 1.2 MPa.

7. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The lifting device (7) is the lifting device for the spray gun on the immersion tube spraying trolley (19).

8. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The frame, hanging rod (9), and net body (10) are all made of 45# steel or 316 stainless steel.

9. The scrap steel utilization device for the RH refining furnace as described in claim 1, characterized in that, The mesh (10) has an aperture of 2-4 cm.

10. A method for utilizing scrap steel using a scrap steel utilization device for an RH refining furnace as described in any one of claims 1 to 9, comprising the following steps: After the previous batch of molten steel is smelted in the S1 and RH refining furnaces, the ladle car transports the ladle away from below the immersion tube (2) and performs spraying maintenance on the immersion tube (2); S2. Fix the vertical tube (11) to the connector (8), insert the mesh sealer (5) into the impregnation tube (2) through the lifting device (7) and lift it to the position of the hanging rod (9) above the upper edge of the impregnation tube (2). Start the air source (6). Under the action of air pressure, the hanging rod (9) slides along the sliding cavity (12) and extends out of the frame so that the mesh sealer (5) hangs on the upper edge of the impregnation tube (2) and seals the impregnation tube (2). S3. Disconnect the vertical tube (11) from the connector (8), and the lifting device (7) falls and leaves below the immersion tube (2); S4. The scrap steel (20) is added to the vacuum tank (1) through the feeding chute (3), and the refractory lining and scrap steel (20) are baked by the top-blown oxygen lance (4). S5. During the smelting of the next batch of molten steel, scrap steel (20) and mesh sealer (5) melt into the molten steel under the circulation of the vacuum tank.

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