Gas protection system and method in metal smelting slagging-off process

Abstract

The invention relates to the technical field of metal smelting, in particular to a gas protection system and method in the metal smelting slagging-off process. The first gas conveying pipe and the high-pressure nozzles are arranged in the smelting furnace, when the inner furnace door is opened for various operations, the high-pressure nozzles spray high-pressure gas downwards, and the gas can be nitrogen, argon or carbon dioxide gas and the like to form a gas curtain for isolating internal and external air on the inner side of the inner furnace door of the smelting furnace; the air curtain can isolate the atmosphere inside and outside the furnace, smoke dust generated when the inner furnace door is opened is prevented from escaping to affect the air environment, meanwhile, heat in the furnace is blocked in the smelting furnace by the air curtain, heat loss is avoided, and production energy consumption and production cost are reduced. The high-pressure gas sprayed by the high-pressure nozzle can also improve the local gas environment in the furnace and at the furnace gate, reduce the content of nearby oxygen, further reduce the burning loss caused by metal oxidation, and further reduce the production cost.

Description

Technical Field

[0001] The invention relates to the technical field of metal smelting, and in particular to a gas protection system and method for a metal smelting slagging process. Background Art

[0002] In the normal production process of a smelting furnace, there are generally operations such as adding materials, melting, refining, slag removal, sampling, adjusting composition, and adjusting temperature. When adding solid materials, refining, sampling, and slag removal, the furnace door needs to be opened. At this time, the smoke and hot air in the furnace will escape through the open furnace door, causing environmental pollution and energy loss.

[0003] Especially in the process of slagging, it is necessary to open the furnace door and use a slagging machine to remove the slag on the surface of the melt from the furnace door. This process will generate a lot of smoke and dust. At the same time, the heat in the furnace will escape to the outside of the furnace with these smoke, causing heat loss, increasing production energy consumption and costs. In addition, since the oxides on the surface of the melt in the furnace will be removed from the furnace door during the slagging process, the metals entrained in the melt and slag will further come into contact with oxygen and become oxides, causing metal loss and further increasing production costs. To this end, we propose a gas protection system and method for the slagging process of metal smelting. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a gas protection system and method for the metal smelting slagging process. When the furnace door is opened for various operations, the high-pressure gas sprayed at the furnace door isolates the atmosphere inside and outside the furnace door. At the same time, the sprayed gas can improve the local gas environment in the furnace and at the furnace door, reduce metal burning loss, and effectively solve the problems in the background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a gas protection system for a metal smelting slag removal process, comprising a smelting furnace, an inner furnace door is arranged at the slag removal port of the smelting furnace, a slag removal machine is arranged on the outside of the smelting furnace, a slag removal rod for removing slag in the smelting furnace is arranged on the slag removal machine, a floor is arranged at the lower part of the outer side of the smelting furnace, a slag bucket is placed on the floor, and a gas recovery port is opened on the upper part of the side surface of the smelting furnace; a first gas pipeline is installed on the smelting furnace near the inner furnace door, the first gas pipeline is connected to an external gas source, and a plurality of high-pressure nozzles are evenly arranged on the lower surface of the first gas pipeline, and the plurality of high-pressure nozzles spray high-pressure gas downward to form an air curtain on the inner side of the inner furnace door of the smelting furnace to isolate the internal and external air.

[0006] As a preferred technical solution of the present invention, a top plate is fixedly provided on the upper outer side of the smelting furnace, and the top plate is arranged on the outer side of the inner furnace door. A second gas pipe and a third gas pipe are sequentially arranged on the lower side of the top plate along the direction away from the first gas pipe. The second gas pipe and the third gas pipe are both connected to an external gas source, and a plurality of high-pressure nozzles are evenly arranged on the lower surfaces of the second gas pipe and the third gas pipe. The high-pressure nozzle of the second gas pipe is arranged above the slag discharge inclined plate on the smelting furnace, and the high-pressure nozzle of the third gas pipe is arranged above the top plate near the slag scraper. The high-pressure nozzles of the second gas pipe and the third gas pipe both spray high-pressure gas downward to form an air curtain between the inner furnace door and the slag scraper to isolate the internal and external air.

[0007] As a preferred technical solution of the present invention, guide plates are arranged on the smelting furnace and the top plate, and the guide plates are arranged on both sides of each group of high-pressure nozzles.

[0008] As a preferred technical solution of the present invention, an outer furnace door is arranged on the top plate. When the outer furnace door and the inner furnace door are closed, a sealing area is formed between the outer furnace door, the inner furnace door, the top plate and the floor. An exhaust pump is installed on the upper surface of the top plate, and the exhaust pipe on the exhaust pump passes through the lower surface of the top plate and enters the sealing area.

[0009] As a preferred technical solution of the present invention, an air source device is installed on the upper surface of the top plate, and an air inlet pipe is provided at the air outlet of the air source device, and the air inlet pipe passes through the lower surface of the top plate and enters the sealing area.

[0010] As a preferred technical solution of the present invention, an oxygen sensor is provided on the air extraction pipe.

[0011] As a preferred technical solution of the present invention, the outer furnace door is hinged at the end of the top plate, a telescopic rod is installed on the inner surface of the outer furnace door, no slag scraper is installed on the outside of the smelting furnace, and the slag scraper rod is arranged at the movable end of the telescopic rod.

[0012] As a preferred technical solution of the present invention, an annular preheating chamber is provided inside the fixed end of the telescopic rod, and the preheating chamber is connected to an external heat source.

[0013] As a preferred technical solution of the present invention, an annular deoxidation sleeve is arranged outside the preheating chamber, and a deoxidizer is arranged inside the deoxidation sleeve.

[0014] As a preferred technical solution of the present invention, two first gas delivery pipes are provided, and the high-pressure nozzles on the two first gas delivery pipes are both inclined.

[0015] The present invention also provides a gas protection method for a metal smelting slag removal process, which uses the above-mentioned gas protection system for a metal smelting slag removal process, and comprises the following steps: S1) Before slagging, close the outer furnace door and turn on the vacuum pump. The vacuum pump will extract the air in the sealed area through the vacuum pipe to remove the oxygen in the sealed area as much as possible; S2) High-temperature gas is introduced into the preheating chamber through an external hot gas source such as a waste heat recovery system of flue gas emission from a smelting furnace to preheat the slag removal rod in the telescopic rod; S3) Turn on the gas source equipment, and the nitrogen, argon or carbon dioxide gas in the gas source equipment enters the sealed area through the air inlet pipe, fills the sealed area and further reduces the oxygen content in the sealed area; S4) opening the first gas delivery pipe and its high-pressure nozzle, the high-pressure nozzle sprays nitrogen, argon or carbon dioxide gas, and forms a downward air curtain through the guide plate to isolate the air circulation inside and outside the smelting furnace; S5) Open the inner furnace door, and then control the extension and retraction of the telescopic rod, which drives the preheated slag removal rod to move into the smelting furnace, and removes the slag on the surface of the melt from the slag removal port into the slag bucket. This process will generate a lot of smoke and dust, which will be blocked in the smelting furnace by the air curtain, and the heat in the furnace will also be blocked in the smelting furnace by the air curtain; S6) After the slag in the smelting furnace is removed, the telescopic rod is controlled to drive the slag removal rod to retract into the sealing area, and then the inner furnace door is closed first, and then the first gas pipe and its high-pressure nozzle are closed, and the smelting furnace continues to work; S7) According to the total amount and temperature of the slag and melt in the slag hopper, the mixture is left to cool for -h. During this process, the air pressure in the sealing area is detected by a barometer installed on the top plate or the outer furnace door, and the air pressure in the sealing area is kept stable and consistent with the external atmospheric pressure by means of air extraction by an air pump or air intake by an air source device; S8) After the melt in the slag hopper cools and solidifies, turn off the vacuum pump and gas source equipment, open the outer furnace door, and continue to cool the slag and the metal formed by the solidification of the melt under the condition of external air circulation. At this time, the surface of the slag and the solidified metal contacts the oxygen in the external air, and the surface is oxidized to form a protective layer to prevent the internal oxidation; S9) After the slag and solidified metal are cooled to a certain temperature, the slag bucket is transported away by an external transfer vehicle to recover the slag and solidified metal; S10) placing the next batch of slag buckets for slagging on the floor, and then closing the outer furnace door; S11) When the slag is removed again, steps S1) to S10) are repeated.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: a first gas delivery pipe and a high-pressure nozzle are arranged in the smelting furnace, and when the inner furnace door is opened for various operations, high-pressure gas is sprayed downward through a plurality of high-pressure nozzles. The gas may be nitrogen, argon or carbon dioxide gas, etc., and an air curtain is formed on the inner side of the inner furnace door of the smelting furnace to isolate the air inside and outside. The air curtain can isolate the atmosphere inside and outside the furnace, and prevent the smoke generated when the inner furnace door is opened from escaping and affecting the air environment. At the same time, the heat in the furnace is also blocked in the smelting furnace by the air curtain, thereby avoiding heat loss and reducing production energy consumption and production costs.

[0017] The high-pressure gas ejected from the high-pressure nozzle can also improve the local gas environment inside the furnace and at the furnace door, reduce the oxygen content nearby, thereby reducing the burning loss caused by metal oxidation and further reducing production costs.

[0018] In addition, when the slag scraper rod scrapes out the slag through the air curtain, a certain amount of heat can be taken away by the high-pressure airflow, thereby shortening the cooling time of the slag and melt and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the structure of the high-pressure nozzle and the guide plate of the present invention; Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 5 For the present invention Figure 4 A magnified view of the structure at A; Figure 6 This is a schematic diagram of the structure of Embodiment 4 of the present invention; Figure 7 This is a structural diagram of Embodiment 5 of the present invention.

[0020] In the figure: 1 smelting furnace, 2 inner furnace door, 3 slag remover, 4 slag remover rod, 5 floor, 6 slag bucket, 7 first gas pipeline, 8 gas recovery port, 9 top plate, 10 second gas pipeline, 11 third gas pipeline, 12 high-pressure nozzle, 13 gas curtain, 14 guide plate, 15 outer furnace door, 16 exhaust pump, 17 exhaust pipe, 18 gas source equipment, 19 air inlet pipe, 20 telescopic rod, 21 oxygen sensor, 22 preheating chamber, 23 deoxidation sleeve. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] For example, see Figure 1-2 The present invention provides a technical solution: a gas protection system for a metal smelting slag removal process, comprising a smelting furnace 1, an inner furnace door 2 is arranged at the slag removal opening of the smelting furnace 1, a slag removal machine 3 is arranged on the outer side of the smelting furnace 1, and a slag removal rod 4 for removing slag in the smelting furnace 1 is arranged on the slag removal machine 3. The smelting furnace 1, the inner furnace door 2, the slag removal machine 3 and the slag removal rod 4 all adopt equipment commonly used in the prior art.

[0023] The smelting furnace 1 is arranged on a floor 5, and a slag bucket 6 for placing slag is also placed on the floor 5. The smelting furnace 1 is also provided with an inclined plate for facilitating the slag to enter the slag bucket 6.

[0024] A gas recovery port 8 is provided on the upper side of the side surface of the smelting furnace 1, and the gas recovery port 8 is connected to an external gas recovery fan, and is used to suck the gas that may be deposited at the bottom of the furnace into the gas recovery pipeline, and introduce it into the dust removal system through the gas recovery fan for treatment before being discharged to meet the standards, so as to avoid the sprayed gas causing harm to the human body.

[0025] A first gas pipe 7 is installed on the smelting furnace 1 near the inner furnace door 2. The first gas pipe 7 is connected to an external gas source, which provides nitrogen, argon or carbon dioxide as a protective gas to the first gas pipe 7.

[0026] A plurality of high-temperature and high-pressure resistant high-pressure nozzles 12, such as silicon carbide nozzles or ceramic nozzles, are evenly arranged on the lower surface of the first gas delivery pipe 7. The spray coverage width of the high-pressure nozzles 12 is 10-20 cm, and the spacing between adjacent high-pressure nozzles is smaller than the spray coverage width of the high-pressure nozzles 12, which is 5-10 cm.

[0027] A plurality of high-pressure nozzles 12 spray high-pressure gas downward to form an air curtain 13 on the inner side of the inner furnace door 2 of the smelting furnace 1 to isolate the inside and outside air. To ensure the effectiveness of the air curtain 13 and to additionally compensate for pipeline loss and nozzle resistance, the pressure of the high-pressure gas can be set within the range of 0.2-0.6 MPa.

[0028] During operation, the gas source provides gas through the gas supply pipeline and the control system to deliver the gas to the high-pressure nozzle 12 through the first gas pipe 7 at a certain pressure. The entire injection system consists of a horizontal pipe embedded in the refractory material on the upper part of the furnace door, the first gas pipe 7, and a row of multiple equally spaced high-pressure nozzles 12 arranged with the same width as the furnace door. The gas is sprayed from top to bottom at a certain pressure through the nozzle system to form an air curtain 13 to isolate the smoke and heat in the furnace to prevent it from overflowing. At the same time, part of the gas will enter the furnace after descending, and part will gather near the furnace door and diffuse to the lower furnace bottom. At this time, the gas (nitrogen, argon or carbon dioxide) entering the furnace can be used as a protective gas to prevent the metal melt in the furnace from further oxidation, and the gas at the furnace door can prevent the hot slag just removed by the slag scraper from further oxidation and causing metal loss.

[0029] In addition, when the slag is removed by the slag removal rod 4 through the air curtain 13, a certain amount of heat can be taken away by the high-pressure airflow, thereby shortening the cooling time of the slag and the melt and improving the production efficiency.

[0030] According to the preferred technical solution, a top plate 9 is fixedly provided on the upper outer side of the smelting furnace 1, and the top plate 9 is provided on the outer side of the inner furnace door 2. The top plate 9 is fixedly installed on the external wall or the mounting frame, and a sliding seal is provided between the inner furnace door 2 and the top plate 9. Whether the inner furnace door 2 is opened or closed, the sealing performance at the contact between the top plate 9 and the top plate 9 is not affected. The second gas pipe 10 and the third gas pipe 11 are sequentially arranged on the lower side of the top plate 9 in a direction away from the first gas pipe 7. The second gas pipe 10 and the third gas pipe 11 are both connected to an external gas source, and a plurality of high-pressure nozzles 12 are evenly arranged on the lower surfaces of the second gas pipe 10 and the third gas pipe 11. The high-pressure nozzle 12 of the second gas pipe 10 is arranged above the slag tapping plate on the smelting furnace 1, and the high-pressure nozzle 12 of the third gas pipe 11 is arranged above the top plate 9 near the slag remover 3. The high-pressure nozzles 12 of the second gas pipe 10 and the high-pressure nozzles 12 of the third gas pipe 11 both spray high-pressure gas downward to form an air curtain 13 between the inner furnace door 2 and the slag remover 3 to isolate the inside and outside air. Sealing plates are also arranged on both sides between the top plate 9 and the floor 5, so that two sealed spaces are formed between the three air curtains 13, thereby further isolating the external oxygen from entering the space where the slag bucket 6 is located, avoiding the slag surface and the melt brought out from contacting with oxygen and being oxidized before solidification, thereby reducing metal burning. At the same time, the three air curtains 13 can further reduce the possibility of smoke and heat escaping from the furnace.

[0031] The distance between the air curtain 13 formed by the first gas pipe 7 and its high-pressure nozzle 12 and the air curtain 13 formed by the second gas pipe 10 and its high-pressure nozzle 12 is greater than the thickness of the inner furnace door 2, and is between 240mm and 300mm; the distance between the air curtain 13 formed by the second gas pipe 10 and its high-pressure nozzle 12 and the air curtain 13 formed by the third gas pipe 11 and its high-pressure nozzle 12 is greater than the width of the slag bucket 6, and is between 600mm and 1200mm. It can be specifically set according to the specifications and width of the slag bucket 6 to ensure that the slag bucket 6 is placed between the two air curtains 13 to isolate external oxygen and reduce metal oxidation burning.

[0032] A further preferred technical solution is that guide plates 14 are provided on the smelting furnace 1 and the top plate 9. The guide plates 14 are provided on both sides of each group of high-pressure nozzles 12. The guide plates 14 are made of commonly used refractory materials. The high-pressure gas ejected from the high-pressure nozzles 12 can more easily form a sealed air curtain 13 through the guidance of the guide plates 14, thereby isolating the air circulation and heat exchange inside and outside.

[0033] For example 2, please refer to Figure 3 This embodiment is substantially the same as the first embodiment, except that: the second gas delivery pipe 10 and the third gas delivery pipe 11 are not provided on the top plate 9, but an outer furnace door 15 is provided on the top plate 9. When the outer furnace door 15 and the inner furnace door 2 are both closed, a sealing area is formed between the outer furnace door 15, the inner furnace door 2, the top plate 9 and the floor 5, and the sealing plates provided on both sides between the top plate 9 and the floor 5. The slag hopper 6 and the slag, molten metal, etc. inside it are located in the sealing area.

[0034] An exhaust pump 16 is installed on the upper surface of the top plate 9. An exhaust pipe 17 on the exhaust pump 16 passes through the lower surface of the top plate 9 and penetrates into the sealing area. The exhaust pump 16 extracts the air in the sealing area through the exhaust pipe 17 to reduce the oxygen content in the sealing area, thereby further reducing the oxidation of the molten metal.

[0035] In a preferred technical solution, a gas source device 18 is installed on the upper surface of the top plate 9. The gas source device 18 can be a high-pressure gas cylinder filled with nitrogen, argon or carbon dioxide gas. The gas outlet of the gas source device 18 is provided with an air inlet pipe 19, which passes through the lower surface of the top plate 9 and penetrates into the sealed area. Nitrogen, argon or carbon dioxide gas is output through the gas source device 18 and the air inlet pipe 19 to fill the sealed area, which can further reduce the oxygen content in the sealed area.

[0036] Compared with the first embodiment, in the present embodiment, during the slagging process, the second gas pipe 10 and the third gas pipe 11 do not need to continuously spray nitrogen, argon or carbon dioxide, etc. It is only necessary to remove the oxygen in the sealing area and keep the gas pressure stable.

[0037] In this embodiment, a through hole for passing the slag scraping rod may be provided on the outer furnace door 15, and a sliding seal is provided between the through hole and the slag scraping rod, so as to facilitate the slag scraping operation and ensure the sealing of the sealing area.

[0038] Optionally, an oxygen sensor 21 is provided on the exhaust pipe 17. The oxygen sensor 21 is used to detect the oxygen content in the air passing through the exhaust pipe 17 during the exhaust process, and transmit the oxygen content information to the controller. The controller analyzes and determines the oxygen content in the sealing area and automatically controls the switches of the exhaust pump 16 and the air source equipment 18, thereby improving the degree of automation.

[0039] In the first and second embodiments, the slag scraper 3 can be equipped with an intelligent slag scraper system, such as the RAMON automatic slag scraper system, which is a large-scale comprehensive system based on machine vision, intelligent sensing, high-performance slag scraper, air blowing and automatic control. The slag scraper can be automatically operated through its machine vision and camera, which has a longer observation distance and higher slag scraper efficiency than manual observation slag scraper.

[0040] For example 3, please refer to Figure 4-5 This embodiment is substantially the same as the second embodiment, except that the outer furnace door 15 is hingedly arranged at the end of the top plate 9, and the outer furnace door 15 is switched by an external cylinder assembly, etc. The outer furnace door 15 opens when it is flipped upward, and closes when it is rotated downward to fit and seal with the floor 5.

[0041] A telescopic rod 20 is installed on the inner surface of the outer furnace door 15, and the telescopic rod 20 can be a multi-stage servo hydraulic cylinder or a multi-stage servo pneumatic cylinder. The telescopic rod 20 is made of materials such as high-temperature alloys or carbon fiber reinforced ceramic matrix composite materials, and can be used to control the telescopic and slag removal operations of the slag removal rod 4. The telescopic rod 20, the oxygen sensor 21, the vacuum pump 16, the valve of the air source device 18, and the air pumps on the first air pipeline 7, the second air pipeline 10, and the third air pipeline 11 are electrically connected to the controller of the uniform smelting system, and the controller can be a commonly used controller model of the existing smelting furnace system.

[0042] In this embodiment, no slag remover 3 is provided outside the smelting furnace 1, and the slag remover rod 4 is provided at the movable end of the telescopic rod 20. When slag removal, the outer furnace door 15 is closed, so that the telescopic rod 20 and the slag remover rod 4 are all inside, and the telescopic rod 20 drives the slag remover rod 4 to move into the smelting furnace 1 to perform the slag removal operation. After the slag removal is completed and the slag and the molten metal are cooled, the telescopic rod 20 drives the slag remover rod 4 to contract and open the outer furnace door 15, so that the telescopic rod 20 and the slag remover rod 4 are moved to the upper side of the outside, so that the slag bucket 6 can be transferred and the slag and the cooled and solidified metal can be recovered.

[0043] Optionally, the telescopic rod 20 is slidably arranged on a guide rail arranged on the inner side of the outer furnace door 15, and a driving component such as a driving screw assembly or a hydraulic cylinder is arranged on the guide rail, which can drive the telescopic rod 20 and the slag removal rod 4 to move along the width direction of the furnace door, thereby removing the slag in the smelting furnace 1 in sequence, which is suitable for slag removal operations of large smelting furnaces.

[0044] Optionally, when a small smelting furnace is used, the furnace door width is narrow, and multiple telescopic rods 20 and slag removal rods 4 can be evenly arranged on the inner side of the outer furnace door 15, and the slag removal operation can be performed on the smelting furnace 1 at the same time to improve the slag removal efficiency. It is suitable for smelting furnaces with a furnace mouth width of less than 6000mm.

[0045] Optionally, an annular preheating chamber 22 is provided inside the fixed end of the telescopic rod 20, and the preheating chamber 22 is connected to an external hot air source, such as a flue gas emission waste heat recovery system of the smelting furnace 1. The slag removal rod 4 inside the telescopic rod 20 is preheated by the waste heat of the flue gas, which can reduce the impact of the slag removal rod 4 on the temperature in the smelting furnace 1 and reduce the carry-out and loss of molten metal.

[0046] The preheating chamber 22 is connected to the flue gas circulation pipeline arranged on the outer furnace door 15. The pipeline can be selected as a high-temperature resistant glass fiber reinforced hose with an outer layer of glass fiber weaving and an inner lining of silicone or ceramic coating. It can follow the opening and closing of the outer furnace door 15 and transport high-temperature gas.

[0047] Further optionally, an annular deoxidation sleeve 23 is provided outside the preheating chamber 22, and a deoxidation agent is provided inside the deoxidation sleeve 23, and the oxygen in the sealing area can be further removed by the deoxidation agent. The deoxidation sleeve 23 is sleeved on the outside of the fixed end of the telescopic rod 20, and can be detached from the telescopic rod 20 for replacement, and the expired deoxidation agent can be replaced to ensure the deoxidation effect.

[0048] Specifically, the inner side of the deoxidizing sleeve 23 is two heat-conducting alloy cylinders with annular cross-sections, one end of the two heat-conducting alloy cylinders is hinged to each other, and the other end is fixed to each other by components such as buckles, and is closely attached to the outer side of the preheating chamber 22 of the telescopic rod 20; the outer side is a highly breathable mesh surface formed by asbestos or glass wool, and the deoxidizer can be selected from cuprous oxide, ferrous oxide or iron powder, etc. Iron powder is preferably used, which can not only accelerate the reaction at high temperature, thereby quickly oxidizing to iron oxide to remove oxygen in the sealing area, but also is economical and can reduce costs.

[0049] The fixed end of the telescopic rod 20 is arranged at the lower part of the inner side of the outer furnace door 15. When the sealed area is evacuated and supplemented with nitrogen, argon or carbon dioxide, the bottom convection is low and there may be some oxygen that has not been evacuated. Therefore, a deoxidizer is provided to assist in deoxidation, so as to further reduce the oxygen content in the sealed area, avoid oxidation of the melt by the residual oxygen at the bottom during slagging, and further reduce metal burning.

[0050] The present invention also provides a gas protection method for a metal smelting slag removal process, which uses the gas protection system for a metal smelting slag removal process of the third embodiment, and comprises the following steps: S1) Before slagging, close the outer furnace door 15 and turn on the vacuum pump 16. The vacuum pump 16 extracts the air in the sealed area through the vacuum pipe 17, so as to remove the oxygen in the sealed area as much as possible, avoid the molten metal from contacting with oxygen and oxidizing in the unsolidified state, and reduce the metal burning loss.

[0051] S2) High-temperature gas is introduced into the preheating chamber 22 through an external hot gas source such as the flue gas exhaust waste heat recovery system of the smelting furnace 1 to preheat the slag removal rod 4 in the telescopic rod 20, thereby reducing the impact of the slag removal rod 4 on the temperature in the smelting furnace 1 and reducing the carryover and loss of molten metal. At the same time, the flue gas waste heat can be effectively utilized, which is beneficial to energy saving and environmental protection.

[0052] While the preheating chamber 22 preheats the slag scraper bar 4, it can heat the deoxidizer such as iron powder in the deoxidizer sleeve 23 to accelerate its reaction with oxygen at high temperature, improve the deoxidation efficiency, and further remove the oxygen in the sealing area.

[0053] S3) Open the valve on the gas source device 18, and the nitrogen, argon or carbon dioxide gas in the gas source device 18 enters the sealed area through the air inlet pipe 19, fills the sealed area and further reduces the oxygen content in the sealed area. At the same time, the air pressure in the sealed area can be kept relatively consistent with the air pressure in the smelting furnace 1 and the external air pressure to avoid adverse effects on the molten metal brought out by the slag.

[0054] S4) Open the first gas delivery pipe 7 and its high-pressure nozzle 12. The high-pressure nozzle 12 sprays nitrogen, argon or carbon dioxide gas, and forms a downward air curtain 13 through the guide plate 14 to isolate the air circulation inside and outside the smelting furnace 1. The air curtain can isolate the atmosphere inside and outside the furnace, and prevent the smoke and dust generated when the inner furnace door is opened from escaping and affecting the air environment. The high-pressure gas sprayed by the high-pressure nozzle can also improve the local gas environment in the furnace and at the furnace door, reduce the oxygen content nearby, and then reduce the burning loss caused by metal oxidation, further reducing production costs.

[0055] S5) Open the inner furnace door 2, and then control the extension and retraction of the telescopic rod 20, and the preheated slag removal rod 4 is driven by the telescopic rod 20 to move into the smelting furnace 1, and the slag on the surface of the melt is removed from the slag removal port to the slag bucket 6. This process will generate a large amount of smoke and dust, which will be blocked in the smelting furnace 1 by the air curtain 13, and the heat in the furnace will also be blocked in the smelting furnace 1 by the air curtain 13, thereby avoiding heat loss and reducing production energy consumption and production costs.

[0056] S6) After the slag in the smelting furnace 1 is removed, the telescopic rod 20 is controlled to drive the slag removal rod 4 to retract into the sealing area. Then the inner furnace door 2 is closed first, and then the first gas pipe 7 and its high-pressure nozzle 12 are closed, and the smelting furnace 1 continues to work.

[0057] S7) According to the total amount and temperature of the slag and melt in the slag hopper 6, the mixture is left to cool for 2-8 hours. During this process, the air pressure in the sealing area is detected by a barometer arranged on the top plate 9 or the outer furnace door 15, and the barometer is electrically connected to the controller of the smelting system. The controller controls the air pump 16 to evacuate air or the air source device 18 to inlet air so that the air pressure in the sealing area is kept stable and consistent with the external atmospheric pressure.

[0058] S8) After the melt in the slag hopper 6 is cooled and solidified, the vacuum pump 16 and the air source device 18 are turned off, and the outer furnace door 15 is opened to continue cooling the slag and the metal formed by the solidification of the melt under the condition of external air circulation. At this time, the surface of the slag and the solidified metal contacts the oxygen in the external air, and the surface is oxidized to form a protective layer, which can prevent the internal oxidation.

[0059] S9) After the slag and solidified metal are cooled to a certain temperature, the slag bucket 6 is transported away by an external transfer vehicle, and then the slag and solidified metal are recovered.

[0060] S10) placing the next batch of slag buckets 6 for slagging on the floor 5, and then closing the outer furnace door 15.

[0061] S11) When the slag is removed again, the above steps are repeated.

[0062] The barometer, telescopic rod 20, oxygen sensor 21, vacuum pump 16, valve of air source device 18 and air pumps and controller on the first air pipe 7, second air pipe 10 and third air pipe 11 used in this application are all electronic components commonly used in the prior art, and their specific structures, working principles, control methods and circuit connections are all well-known technologies and will not be described in detail here.

[0063] Example 4, please refer to Figure 6 This embodiment is roughly the same as the first, second and third embodiments, except that: two first air delivery pipes 7 are provided, and the high-pressure nozzles 12 on the two first air delivery pipes 7 are both inclined, with an inclination angle of 15-45°. And the two groups of high-pressure nozzles 12 are inclined toward each other. Two rows of nozzles are symmetrically distributed, and the nozzles are inclined toward the center line. After the airflows on both sides collide at the center, a high-pressure area is formed, which can enhance the airtightness of the air curtain 13.

[0064] For example 5, please refer to Figure 7This embodiment is roughly the same as the fourth embodiment, except that: the several high-pressure nozzles 12 on the two first air pipes 7 are staggered with each other, which can reduce the gaps between the airflows and increase the uniformity of the air curtain 13 coverage. The aligned high-pressure nozzles 12 may have areas that the airflow cannot cover. The staggered arrangement can fill these gaps and form a more continuous air curtain. In addition, the staggered arrangement may change the angle and position of the airflow collision, allowing the airflow to interact at more points and form more complex turbulence, thereby enhancing the barrier effect. The staggered arrangement can also make the pressure distribution more uniform and reduce local high-pressure or low-pressure areas, so that the overall stability of the air curtain is better. Especially when the furnace door is just opened, there is external airflow interference, and the air curtain 13 formed by the staggered high-pressure nozzles 12 can more effectively resist interference.

[0065] The undisclosed parts in the present invention are all prior art, and their specific structures, materials and working principles are not described in detail. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A gas protection system for a metal smelting slag removal process, comprising a smelting furnace (1), an inner furnace door (2) being arranged at a slag removal opening of the smelting furnace (1), a slag removal machine (3) being arranged outside the smelting furnace (1), and a slag removal rod (4) being arranged on the slag removal machine (3) for removing slag from the smelting furnace (1), characterized in that: The smelting furnace (1) is arranged on a floor (5), a slag bucket (6) is placed on the floor (5), and a gas recovery port (8) is opened on the upper side surface of the smelting furnace (1); a first gas pipeline (7) is installed on the smelting furnace (1) near the inner furnace door (2), the first gas pipeline (7) is connected to an external gas source, and a plurality of high-pressure nozzles (12) are evenly arranged on the lower surface of the first gas pipeline (7), and the plurality of high-pressure nozzles (12) spray high-pressure gas downward to form an air curtain (13) on the inner side of the inner furnace door (2) of the smelting furnace (1) to isolate the internal and external air.

2. A gas protection system for metal smelting slagging process according to claim 1, characterized in that: A top plate (9) is fixedly arranged on the upper outer portion of the smelting furnace (1), the top plate (9) being arranged on the outer side of the inner furnace door (2), a second gas pipe (10) and a third gas pipe (11) being arranged in sequence on the lower side of the top plate (9) in a direction away from the first gas pipe (7), the second gas pipe (10) and the third gas pipe (11) being both connected to an external gas source, and a plurality of high-pressure nozzles (12) being evenly arranged on the lower surfaces of the second gas pipe (10) and the third gas pipe (11), The high-pressure nozzle (12) of the second gas pipe (10) is arranged above the slag tapping inclined plate on the smelting furnace (1), and the high-pressure nozzle (12) of the third gas pipe (11) is arranged above the top plate (9) near the slag remover (3). The high-pressure nozzle (12) of the second gas pipe (10) and the high-pressure nozzle (12) of the third gas pipe (11) both spray high-pressure gas downward to form an air curtain (13) between the inner furnace door (2) and the slag remover (3) to isolate the inside and outside air.

3. A gas protection system for metal smelting slagging process according to claim 2, characterized in that: Guide plates (14) are provided on the smelting furnace (1) and the top plate (9), and the guide plates (14) are provided on both sides of each group of high-pressure nozzles (12).

4. A gas protection system for metal smelting slagging process according to claim 3, characterized in that: The top plate (9) is provided with an outer furnace door (15), and when the outer furnace door (15) and the inner furnace door (2) are both closed, a sealed area is formed between the outer furnace door (15), the inner furnace door (2), the top plate (9) and the floor (5); an air extraction pump (16) is installed on the upper surface of the top plate (9), and an air extraction pipe (17) on the air extraction pump (16) passes through the lower surface of the top plate (9) and penetrates into the sealed area.

5. A gas protection system for metal smelting slagging process according to claim 4, characterized in that: An air source device (18) is installed on the upper surface of the top plate (9), and an air inlet pipe (19) is provided at the air outlet of the air source device (18). The air inlet pipe (19) passes through the lower surface of the top plate (9) and enters the sealing area.

6. A gas protection system for metal smelting slagging process according to claim 5, characterized in that: An oxygen sensor (21) is provided on the air extraction pipe (17).

7. A gas protection system for metal smelting slagging process according to claim 6, characterized in that: The outer furnace door (15) is hingedly arranged at the end of the top plate (9), and a telescopic rod (20) is installed on the inner surface of the outer furnace door (15). No slag scraper (3) is arranged outside the smelting furnace (1), and the slag scraper rod (4) is arranged at the movable end of the telescopic rod (20).

8. A gas protection system for metal smelting slagging process according to claim 7, characterized in that: An annular preheating chamber (22) is provided inside the fixed end of the telescopic rod (20), and the preheating chamber (22) is connected to an external heat source.

9. A gas protection system for metal smelting slagging process according to any one of claims 1 to 8, characterized in that: Two first air delivery pipes (7) are provided, and the high-pressure nozzles (12) on the two first air delivery pipes (7) are both arranged at an angle.

10. A gas protection method for metal smelting slagging process, characterized in that: The gas protection system for the metal smelting slagging process according to claim 8 comprises the following steps: S1) Before slagging, close the outer furnace door (15), turn on the vacuum pump (16), and the vacuum pump (16) extracts the air in the sealed area through the vacuum pipe (17) to remove as much oxygen as possible in the sealed area; S2) introducing high-temperature gas into the preheating chamber (22) through an external hot gas source, such as a flue gas exhaust waste heat recovery system of the smelting furnace (1), to preheat the slag removal rod (4) in the telescopic rod (20); S3) turning on the gas source device (18), and the nitrogen, argon or carbon dioxide gas in the gas source device (18) enters the sealed area through the gas inlet pipe (19), fills the sealed area and further reduces the oxygen content in the sealed area; S4) opening the first gas delivery pipe (7) and its high-pressure nozzle (12), so that the high-pressure nozzle (12) sprays nitrogen, argon or carbon dioxide gas to form a downward air curtain (13) through the guide plate (14), thereby isolating the air flow inside and outside the smelting furnace (1); S5) opening the inner furnace door (2), and then controlling the extension and retraction of the telescopic rod (20), so that the preheated slag removal rod (4) is driven by the telescopic rod (20) to move into the smelting furnace (1), and the slag on the surface of the molten liquid is removed from the slag removal port into the slag bucket (6). This process generates a large amount of smoke and dust, which is blocked by the air curtain (13) in the smelting furnace (1), and at the same time, the heat in the furnace is also blocked by the air curtain (13) in the smelting furnace (1); S6) After the slag in the smelting furnace (1) is removed, the telescopic rod (20) is controlled to drive the slag removal rod (4) to retract into the sealing area, and then the inner furnace door (2) is closed first, and then the first gas supply pipe (7) and its high-pressure nozzle (12) are closed, and the smelting furnace (1) continues to operate; S7) according to the total amount and temperature of the slag and melt in the slag hopper (6), the furnace is left to cool for 2-8 hours. During this process, the air pressure in the sealing area is detected by a barometer arranged on the top plate (9) or the outer furnace door (15), and the air pressure in the sealing area is kept stable and consistent with the external atmospheric pressure by means of air extraction by an air pump (16) or air intake by an air source device (18); S8) After the melt in the slag hopper (6) is cooled and solidified, the vacuum pump (16) and the air source device (18) are turned off, and the outer furnace door (15) is opened to continue cooling the slag and the metal formed by the solidification of the melt under the condition of external air circulation. At this time, the surface of the slag and the solidified metal contacts the oxygen in the external air, and the surface is oxidized to form a protective layer to prevent the internal oxidation; S9) After the slag and solidified metal are cooled to a certain temperature, the slag bucket (6) is transported away by an external transfer vehicle to recover the slag and solidified metal; S10) placing the next batch of slag buckets (6) for slagging on the floor (5), and then closing the outer furnace door (15); S11) When the slag is removed again, steps S1) to S10) are repeated.

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