A gas protection system and method for metal smelting slagging process

Abstract

The present invention relates to the field of metal smelting technology, and specifically to a gas protection system and method for the slag removal process of metal smelting. A first gas pipe and a high-pressure nozzle are provided in the smelting furnace. When the inner furnace door is opened to perform various operations, high-pressure gas is sprayed downward through a number of high-pressure nozzles. The gas can be nitrogen, argon or carbon dioxide gas, etc., forming an air curtain 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 and dust 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, avoiding heat loss, reducing production energy consumption and production costs. 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 thereby reduce the burning loss caused by metal oxidation, further reducing production costs.

Description

Technical Field

[0001] The present 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] During 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] In particular, during the deslagging process, the furnace door must be opened and a deslagging machine must be used to remove the slag from the surface of the melt. This process generates a large amount of smoke and dust, and the heat within the furnace escapes with this smoke, causing heat loss and increasing production energy consumption and costs. Furthermore, since oxides on the surface of the melt are scraped out of the furnace door during deslagging, metal trapped in the melt and slag will further come into contact with oxygen and become oxides, causing metal loss and further increasing production costs. To address this issue, we propose a gas protection system and method for the deslagging process in 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 ejected from the furnace door isolates the atmosphere inside and outside the furnace door. At the same time, the ejected 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 objectives, 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 being provided at the slag removal port of the smelting furnace, a slag remover being provided on the outside of the smelting furnace, a slag remover being provided on the slag remover being provided with a slag removal rod for removing slag in the smelting furnace, a floor being provided at the lower portion of the outer side of the smelting furnace, a slag bucket being placed on the floor, and a gas recovery port being provided on the upper portion of the side surface of the smelting furnace; a first gas pipe being installed on the smelting furnace near the inner furnace door, the first gas pipe being connected to an external gas source, and a plurality of high-pressure nozzles being evenly provided on the lower surface of the first gas pipe, the plurality of high-pressure nozzles spraying 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 inside and outside 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 provided on the outer side of the inner furnace door. A second gas pipe and a third gas pipe are sequentially provided 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 number of high-pressure nozzles are evenly provided on the lower surfaces of the second gas pipe and the third gas pipe. The high-pressure nozzle of the second gas pipe is provided above the slag discharge inclined plate on the smelting furnace, and the high-pressure nozzle of the third gas pipe is provided 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 inside and outside air.

[0007] As a preferred technical solution of the present invention, guide plates are provided on the smelting furnace and the top plate, and the guide plates are provided 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 provided on the top plate. When the outer furnace door and the inner furnace door are closed, a sealed 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 sealed 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, which 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 exhaust pipe.

[0011] As an optimal 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 is set 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 provided outside the preheating chamber, and a deoxidizer is provided inside the deoxidation sleeve.

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

[0015] The present invention also provides a gas protection method for a metal smelting slag stripping process, which uses the above-mentioned gas protection system for a metal smelting slag stripping process, comprising the following steps:

[0016] 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 as much oxygen as possible.

[0017] S2) High-temperature gas is introduced into the preheating chamber through an external hot gas source, such as the flue gas exhaust waste heat recovery system of the smelting furnace, to preheat the slag scraper rod inside the telescopic rod;

[0018] 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, filling the sealed area and further reducing the oxygen content in the sealed area;

[0019] S4) Opening the first gas supply pipe and its high-pressure nozzle, the high-pressure nozzle sprays nitrogen, argon or carbon dioxide gas, which forms a downward air curtain through the guide plate to isolate the air circulation inside and outside the smelting furnace;

[0020] S5) Open the inner furnace door and control the extension and retraction of the telescopic rod, which drives the preheated slag scraper rod into the melting furnace. The slag on the surface of the melt is removed from the slag scraper opening into the slag hopper. This process generates a large amount of smoke and dust, which is blocked by the air curtain in the melting furnace. At the same time, the heat in the furnace is also blocked by the air curtain.

[0021] 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 operate;

[0022] S7) Based on the total amount and temperature of the slag and melt in the hopper, the mixture is allowed to cool for -h. During this process, the air pressure in the sealed area is detected by a barometer installed on the top plate or the outer furnace door. The air pressure in the sealed area is kept stable by pumping air through an air pump or by supplying air through an air source device, and is kept consistent with the external atmospheric pressure.

[0023] S8) After the melt in the slag hopper cools and solidifies, turn off the vacuum pump and air 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 solidified metal comes into contact with oxygen in the external air, and the surface is oxidized to form a protective layer to prevent internal oxidation;

[0024] S9) After the slag and solidified metal cool to a certain temperature, the slag bucket is transported away by an external transfer car to recover the slag and solidified metal;

[0025] S10) Place the next batch of slag buckets on the floor, and then close the outer furnace door;

[0026] S11) When scraping again, repeat steps S1) to S10).

[0027] 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 provided 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., forming an air curtain 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, preventing the smoke and dust 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, avoiding heat loss and reducing production energy consumption and production costs.

[0028] 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.

[0029] In addition, when the slag is removed by the scraper rod 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

[0030] Figure 1 This is a schematic structural diagram of embodiment 1 of the present invention;

[0031] Figure 2 Schematic diagram of the structure of the high-pressure nozzle and guide plate of the present invention;

[0032] Figure 3 This is a structural diagram of embodiment 2 of the present invention;

[0033] Figure 4 This is a structural diagram of embodiment 3 of the present invention;

[0034] Figure 5 For the present invention Figure 4 A magnified view of the structure at point A;

[0035] Figure 6 This is a structural diagram of a fourth embodiment of the present invention;

[0036] Figure 7 This is a structural diagram of embodiment 5 of the present invention.

[0037] In the figure: 1 smelting furnace, 2 inner furnace door, 3 slag scraper, 4 slag scraper rod, 5 floor, 6 slag bucket, 7 first gas pipe, 8 gas recovery port, 9 top plate, 10 second gas pipe, 11 third gas pipe, 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

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0039] For example 1, please refer to Figure 1-2 The present invention provides a technical solution: a gas protection system for the slag removal process of metal smelting, comprising a smelting furnace 1, an inner furnace door 2 is provided at the slag removal opening of the smelting furnace 1, a slag remover 3 is provided on the outside of the smelting furnace 1, and a slag remover rod 4 is provided on the slag remover 3 for removing slag in the smelting furnace 1. The smelting furnace 1, the inner furnace door 2, the slag remover 3 and the slag remover rod 4 all adopt equipment commonly used in the prior art.

[0040] 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 allowing the slag that is conveniently scraped out to enter the slag bucket 6.

[0041] A gas recovery port 8 is provided on the upper side of the smelting furnace 1. This port is connected to an external gas recovery blower and is used to draw gas that may have accumulated at the furnace bottom into a gas recovery pipe. The gas recovery blower then directs the gas into a dust removal system for treatment before discharging the gas to meet standards. This prevents any harm to the human body caused by the ejected gas.

[0042] 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.

[0043] The lower surface of the first gas pipe 7 is uniformly provided with a plurality of high-temperature and high-pressure nozzles 12, such as silicon carbide nozzles or ceramic nozzles. 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.

[0044] Several high-pressure nozzles 12 spray high-pressure gas downward, forming an air curtain 13 on the inside of the inner furnace door 2 of the smelting furnace 1, isolating the inside and outside air. To ensure the effectiveness of the air curtain 13 and to compensate for pipeline losses and nozzle resistance, the high-pressure gas pressure can be set within the range of 0.2–0.6 MPa.

[0045] During operation, the gas source provides gas through the gas supply pipeline and control system, delivering it at a constant pressure through the first gas pipe 7 to the high-pressure nozzle 12. The entire gas injection system consists of a horizontal pipe embedded in the refractory material above the furnace door, the first gas pipe 7, and a row of multiple equally spaced high-pressure nozzles 12, the same width as the furnace door. The gas is ejected downward at a constant pressure through the nozzle system, forming an air curtain 13 that isolates the flue gas and heat within the furnace and prevents them from escaping. As the gas descends, some enters the furnace, while some gathers near the furnace door and diffuses toward the lower furnace bottom. The gas (nitrogen, argon, or carbon dioxide) entering the furnace acts as a shielding gas to prevent further oxidation of the molten metal within the furnace, while the gas at the furnace door prevents further oxidation of the hot slag just removed by the slag scraper, which could cause metal loss.

[0046] In addition, when the slag is scraped out by the scraping rod 4 and passes 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 production efficiency.

[0047] The preferred technical solution is that a top plate 9 is fixedly provided on the upper outer side of the smelting furnace 1, the top plate 9 is arranged on the outer side of the inner furnace door 2, the top plate 9 is fixedly mounted on the external wall or mounting frame, and a sliding seal is provided between the inner furnace door 2 and the top plate 9, and the opening or closing of the inner furnace door 2 does not affect the sealing of the contact between the inner furnace door 2 and the top plate 9. A second gas pipe 10 and a third gas pipe 11 are disposed sequentially on the underside of the top plate 9, away from the first gas pipe 7. Both the second and third gas pipes 10, 11 are connected to an external gas source. A plurality of high-pressure nozzles 12 are evenly distributed on their lower surfaces. The high-pressure nozzles 12 of the second gas pipe 10 are located above the slag tapping ramp on the smelting furnace 1, while the high-pressure nozzles 12 of the third gas pipe 11 are located above the top plate 9 near the slag scraper 3. Both the high-pressure nozzles 12 of the second and third gas pipes 10, 11 spray high-pressure gas downward, forming an air curtain 13 between the inner furnace door 2 and the slag scraper 3 to isolate the interior and exterior air. Sealing plates are also disposed on both sides between the top plate 9 and the floor 5, forming two sealed spaces between the three air curtains 13. This further isolates external oxygen from entering the space within the slag hopper 6, preventing the slag surface and the unsolidified molten liquid from coming into contact with oxygen and being oxidized, thereby reducing metal burnout. At the same time, the three air curtains 13 can further reduce the possibility of smoke and heat escaping from the furnace.

[0048] 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 240 mm and 300 mm; 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 hopper 6, and is between 600 mm and 1200 mm. The specific setting can be made according to the specifications and width of the slag hopper 6 to ensure that the slag hopper 6 is placed between the two air curtains 13, isolated from external oxygen, and reduce metal oxidation and burning.

[0049] 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 arranged 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 nozzle 12 is more easily formed into a sealed air curtain 13 through the guidance of the guide plates 14, thereby isolating the air circulation and heat exchange inside and outside.

[0050] For example 2, please refer to Figure 3 This embodiment is substantially the same as the first embodiment, differing in that the second and third gas pipes 10, 11, etc. are not provided on the top plate 9. Instead, an outer furnace door 15 is provided on the top plate 9. When both the outer furnace door 15 and the inner furnace door 2 are closed, a sealed area is formed between the outer furnace door 15, the inner furnace door 2, the top plate 9, 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. contained therein are located within this sealed area.

[0051] 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 into the sealing area. The exhaust pump 16 extracts the air in the sealing area through the exhaust pipe 17, reducing the oxygen content in the sealing area, thereby further reducing the oxidation of the molten metal.

[0052] In a preferred technical solution, a gas source device 18 is mounted on the upper surface of the top plate 9. Gas source device 18 can be a high-pressure gas cylinder filled with nitrogen, argon, or carbon dioxide. An inlet pipe 19 is provided at the outlet of gas source device 18. Inlet pipe 19 passes through the lower surface of the top plate 9 and into the sealed area. Nitrogen, argon, or carbon dioxide is delivered through gas source device 18 and inlet pipe 19 to fill the sealed area, further reducing the oxygen content in the sealed area.

[0053] Compared with the first embodiment, this embodiment does not require the second gas pipe 10 and the third gas pipe 11 to continuously spray nitrogen, argon or carbon dioxide gas during the slagging process. It is only necessary to remove the oxygen in the sealing area and maintain a stable air pressure.

[0054] In this embodiment, a through hole for passing the slag scraping rod can be provided on the outer furnace door 15, and a sliding seal is provided between the through hole and the slag scraping rod to facilitate the slag scraping operation while ensuring the sealing of the sealing area.

[0055] 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.

[0056] In Examples 1 and 2, the scraper 3 can be equipped with an intelligent scraping system, such as the RAMON automatic scraping system. The RAMON automatic scraping system is a large, comprehensive system based on machine vision, intelligent sensing, a high-performance scraper, air blowing to remove slag, and automatic control. Its machine vision and camera functions enable automated scraping operations, allowing for greater observation distance and improved scraping efficiency compared to manual observation.

[0057] For example three, please refer to Figure 4-5 This embodiment is roughly the same as the second embodiment, with the difference being that the outer furnace door 15 is hingedly arranged at the end of the top plate 9, and the outer furnace door 15 is controlled to open and close 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.

[0058] A telescopic rod 20 is mounted on the inner surface of the outer furnace door 15. This rod can be a multi-stage servo hydraulic cylinder or a multi-stage servo pneumatic cylinder. Made of materials such as high-temperature alloys or carbon fiber-reinforced ceramic matrix composites, the rod 20 controls the extension and retraction of the slag scraping rod 4 and other slag scraping operations. The rod 20, oxygen sensor 21, vacuum pump 16, valves on the air source 18, and the air pumps on the first, second, and third air pipes 11 are electrically connected to a controller for the uniform smelting system. This controller can be a commonly used controller for existing smelting furnace systems.

[0059] In this embodiment, the slag scraper 3 is not installed outside the smelting furnace 1. Instead, the slag scraper 4 is located at the movable end of a telescopic rod 20. During slag removal, the outer furnace door 15 is closed, positioning the telescopic rod 20 and the slag scraper 4 inside. The telescopic rod 20 then drives the slag scraper 4 into the smelting furnace 1 to perform the slag removal operation. After slag removal is complete and the slag and molten metal have cooled, the telescopic rod 20 retracts the slag scraper 4, opening the outer furnace door 15 and moving the telescopic rod 20 and the slag scraper 4 to the upper exterior side. The slag bucket 6 can then be transferred and the slag and cooled, solidified metal recovered.

[0060] Optionally, the telescopic rod 20 is slidably set on a guide rail set on the inner side of the outer furnace door 15, and a driving component such as a driving screw component or a hydraulic cylinder is set on the guide rail, which can drive the telescopic rod 20 and the slag scraping rod 4 to move along the width direction of the furnace door, thereby scraping out the slag in the smelting furnace 1 in sequence, which is suitable for slag scraping operations in large smelting furnaces.

[0061] Optionally, when using a small smelting furnace with a narrow furnace door, multiple telescopic rods 20 and slag removal rods 4 can be evenly arranged on the inner side of the outer furnace door 15 to simultaneously perform slag removal operations on the smelting furnace 1, thereby improving slag removal efficiency. This is suitable for smelting furnaces with a furnace opening width of less than 6000 mm.

[0062] 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 the flue gas exhaust waste heat recovery system of the smelting furnace 1. The slag 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 rod 4 on the temperature inside the smelting furnace 1 and reduce the carry-out and loss of molten metal.

[0063] The preheating chamber 22 is connected to the flue gas circulation pipeline set on the outer furnace door 15. The pipeline can be selected as a high-temperature resistant glass fiber reinforced hose with a glass fiber braided outer layer and a silicone or ceramic coating lining. It can follow the opening and closing of the outer furnace door 15 and transport high-temperature gas.

[0064] Optionally, an annular deoxidizing sleeve 23 is provided outside the preheating chamber 22. A deoxidizing agent is disposed within the deoxidizing sleeve 23 to further remove oxygen from the sealed area. The deoxidizing sleeve 23 is sleeved onto the outside of the fixed end of the telescopic rod 20 and can be removed from the rod 20 for replacement, allowing any deoxidizing agent to be replaced to ensure effective deoxidation.

[0065] Specifically, the inner side of the deoxidizing sleeve 23 comprises two heat-conducting alloy cylinders with an annular cross-section. These cylinders are hinged at one end and secured to each other at the other end by a buckle or other assembly, tightly fitting the outer side of the preheating chamber 22 of the telescopic rod 20. The outer side comprises a highly breathable mesh surface formed of asbestos or glass wool. The deoxidizer can be cuprous oxide, ferrous oxide, or iron powder. Iron powder is preferred because it not only accelerates the reaction at high temperatures, quickly oxidizing to iron oxide and removing oxygen from the sealed area, but is also economical and reduces costs.

[0066] 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 gas, the convection at the bottom is low, and some oxygen that has not been evacuated may exist. Therefore, a deoxidizer is provided to assist in deoxidation, thereby further reducing the oxygen content in the sealed area and preventing the residual oxygen at the bottom from oxidizing the melt during slagging, thereby further reducing metal burn loss.

[0067] The present invention further provides a gas protection method for a metal smelting slag stripping process, which uses the gas protection system for a metal smelting slag stripping process of the third embodiment, and includes the following steps:

[0068] 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 to remove as much oxygen as possible in the sealed area, preventing the molten metal from coming into contact with oxygen and being oxidized in the unsolidified state, thereby reducing metal burnout.

[0069] S2) High-temperature gas is introduced into the preheating chamber 22 from an external hot gas source, such as the flue gas exhaust waste heat recovery system of the smelting furnace 1, to preheat the slag scraper 4 within the telescopic rod 20. This reduces the impact of the slag scraper 4 on the temperature within the smelting furnace 1 and reduces carryover and loss of molten metal. Furthermore, the flue gas waste heat is effectively utilized, contributing to energy conservation and environmental protection.

[0070] While the preheating chamber 22 preheats the scraper bar 4, it can also 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 oxygen in the sealing area.

[0071] S3) The valve on gas source device 18 is opened, and the nitrogen, argon, or carbon dioxide gas in gas source device 18 enters the sealed area through gas inlet pipe 19, filling the sealed area and further reducing the oxygen content in the sealed area. At the same time, the air pressure in the sealed area is kept relatively consistent with the air pressure in smelting furnace 1 and the external air pressure, thereby preventing any adverse effects on the molten metal carried over by the slag.

[0072] S4) The first gas supply pipe 7 and its high-pressure nozzle 12 are opened. Nitrogen, argon, or carbon dioxide is ejected from the high-pressure nozzle 12, forming a downward air curtain 13 through the guide plate 14, isolating the air flow inside and outside the smelting furnace 1. The air curtain isolates the atmosphere inside and outside the furnace, preventing smoke and dust generated when the inner furnace door is opened from escaping and affecting the air environment. The high-pressure gas ejected from the high-pressure nozzle also improves the local gas environment inside the furnace and at the furnace door, reducing the oxygen content nearby, thereby reducing burn damage caused by metal oxidation and further reducing production costs.

[0073] S5) Open the inner furnace door 2, then control the extension and retraction of the telescopic rod 20, which drives the preheated slag scraper rod 4 into the smelting furnace 1. The slag on the surface of the melt is removed from the slag scraper opening into the slag hopper 6. This process generates a large amount of smoke and dust, which is trapped within the smelting furnace 1 by the air curtain 13. Simultaneously, the heat within the furnace is also trapped within the smelting furnace 1 by the air curtain 13, preventing heat loss and reducing energy consumption and production costs.

[0074] S6) After the slag in the smelting furnace 1 is removed, the telescopic rod 20 is controlled to retract the slag removal rod 4 into the sealed area. The inner furnace door 2 is then closed, followed by the first gas pipe 7 and its high-pressure nozzle 12, and the smelting furnace 1 continues to operate.

[0075] S7) Allow the slag and melt in the hopper 6 to cool for 2-8 hours, depending on the total amount and temperature of the slag and melt. During this time, the air pressure in the sealed area is monitored using a barometer located on the top plate 9 or the outer furnace door 15. The barometer is electrically connected to the controller of the smelting system. The controller controls the air pump 16 to extract air or the air source device 18 to supply air, so that the air pressure in the sealed area remains stable and consistent with the external atmospheric pressure.

[0076] S8) After the melt in hopper 6 cools and solidifies, the vacuum pump 16 and air source 18 are turned off, and the outer furnace door 15 is opened to allow air to circulate, continuing to cool the slag and the solidified metal. The surfaces of the slag and solidified metal come into contact with oxygen in the outside air, oxidizing them and forming a protective layer that prevents internal oxidation.

[0077] S9) After the slag and solidified metal cool to a certain temperature, the slag bucket 6 is transported away by an external transfer vehicle, and the slag and solidified metal are then recovered.

[0078] S10) Place the next batch of slag buckets 6 on the floor 5, and then close the outer furnace door 15.

[0079] S11) When scraping again, repeat the above steps.

[0080] The barometer, telescopic rod 20, oxygen sensor 21, vacuum pump 16, valve of the gas source device 18, and the air pumps and controllers on the first gas pipe 7, the second gas pipe 10, and the third gas pipe 11 used in this application are all electronic components commonly used in the prior art. Their specific structure, working principle, control method, and circuit connection are all well-known technologies and will not be described in detail here.

[0081] For example 4, please refer to Figure 6 This embodiment is substantially similar to Embodiments 1, 2, and 3, differing in that two first air delivery pipes 7 are provided, and the high-pressure nozzles 12 on each first air delivery pipe 7 are tilted at an angle of 15-45°. Furthermore, both sets of high-pressure nozzles 12 are tilted toward each other. Two rows of nozzles are symmetrically distributed, with spray angled toward the centerline. The collision of the two airflows at the center creates a high-pressure zone, which enhances the airtightness of the air curtain 13.

[0082] For example five, please refer to Figure 7This embodiment is roughly the same as the fourth embodiment, with the difference 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, and the staggered arrangement can fill these gaps to 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, forming 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.

[0083] Any undisclosed portions of the present invention are prior art, and their specific structures, materials, and operating principles will not be described in detail. Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas protection system for a metal smelting slag removal process, comprising a smelting furnace (1), wherein an inner furnace door (2) is provided at a slag removal opening of the smelting furnace (1), and 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 provided on the upper side surface of the smelting furnace (1); 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, and a plurality of high-pressure nozzles (12) are evenly arranged on the lower surface of the first gas pipe (7), 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 inside and outside air; a top plate (9) is fixedly provided on the upper outer side of the smelting furnace (1), the top plate (9) is provided on the outer side of the inner furnace door (2), and 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 all closed, the outer furnace door (15), the inner furnace door (2), and the top plate (9) and the floor (5) form a sealed area; 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); the outer side of the smelting furnace (1) is not provided with a slag scraper (3), and the slag scraper rod (4) is arranged at the movable end of the telescopic rod (20); an annular preheating chamber (22) is arranged inside the fixed end of the telescopic rod (20), and the fixed end of the telescopic rod (20) is arranged at the lower part of the inner side of the outer furnace door (15); an annular deoxidation sleeve (23) is arranged outside the preheating chamber (22), and a deoxidizer is arranged inside the deoxidation sleeve (23); high-temperature gas is introduced into the preheating chamber (22) to preheat the slag scraper rod (4) in the telescopic rod (20); the preheating chamber (22) preheats the slag scraper rod (4) and heats the deoxidizer in the deoxidation sleeve (23); An air 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 into the sealing area. The air extraction pump (16) extracts the air in the sealing area through the air extraction pipe (17); 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 sealed area. Nitrogen, argon or carbon dioxide gas in the air source device (18) enters the sealed area through the air inlet pipe (19).

2. A gas protection system for metal smelting slagging process according to claim 1, 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).

3. A gas protection system for metal smelting slagging process according to claim 2, characterized in that: An oxygen sensor (21) is provided on the air extraction pipe (17).

4. A gas protection system for metal smelting slagging process according to claim 3, characterized in that: The preheating chamber (22) is in communication with an external heat source.

5. A gas protection system for metal smelting slagging process according to any one of claims 1 to 4, 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.

6. A gas protection method for metal smelting slagging process, characterized by: The gas protection system for the metal smelting slagging process according to claim 4 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 to preheat the slag scraping 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 air inlet pipe (19), filling the sealed area and further reducing the oxygen content in the sealed area; S4) opening the first gas supply pipe (7) and its high-pressure nozzle (12), so that the high-pressure nozzle (12) ejects nitrogen, argon or carbon dioxide gas, forming a downward air curtain (13) through the guide plate (14), isolating the air flow inside and outside the smelting furnace (1); S5) Open the inner furnace door (2), then control the extension and retraction of the telescopic rod (20), and the preheated slag scraping 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 scraped out from the slag scraping 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 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 pipe (7) and its high-pressure nozzle (12) are closed, and the smelting furnace (1) continues to operate; S7) Based on 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 installed on the top plate (9) or the outer furnace door (15), and the air pressure in the sealing area is kept stable by pumping air through the air pump (16) or by introducing air through the air source device (18) so as to be consistent with the external atmospheric pressure. S8) After the melt in the slag hopper (6) cools and solidifies, the vacuum pump (16) and the air source device (18) are turned off, and the outer furnace door (15) is opened. The slag and the metal formed by the solidification of the melt are further cooled 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 cool to a certain temperature, the slag bucket (6) is transported away by an external transfer trolley to recover the slag and solidified metal; S10) placing the next batch of slag buckets (6) for slag removal on the floor (5), and then closing the outer furnace door (15); S11) When scraping again, repeat steps S1) to S10).

Images