Closed powder spraying system in steelmaking and tapping process of electric arc furnace and using method

Abstract

The invention provides a closed powder spraying system in the steelmaking tapping process of an electric arc furnace and a using method, and relates to the technical field of electric arc furnace steelmaking. The closed powder spraying system in the electric arc furnace steelmaking tapping process comprises an electric arc furnace, a closed powder spraying device, a steel ladle, a powder spraying system, a gas supply system and a computer control system. The electric arc furnace is communicated with the steel ladle through the closed powder spraying device, the closed powder spraying device is communicated with the powder spraying system and the gas supply system, the powder spraying system is communicated with the gas supply system, and the computer control system is electrically connected with the electric arc furnace, the closed powder spraying device, the steel ladle, the powder spraying system and the gas supply system for control. The relation between the deoxidation and desulfurization effect and the powder spraying amount can be accurately controlled, the using amount of a reducing agent, a slag former and an alloy is reduced, and the smelting production rhythm can be shortened while the molten steel components are effectively stabilized; the method is low in cost, short in process, high in production efficiency and beneficial to industrial large-scale production, popularization and application.

Description

Technical Field

[0001] This invention relates to the technical field of electric arc furnace steelmaking, and in particular to a closed powder injection system and its usage method for the tapping process of electric arc furnace steelmaking. Background Technology

[0002] Electric arc furnace (EAF) steelmaking boasts advantages such as a short process, low energy consumption, and low carbon emissions. However, the control of O, S, N, and H content during EAF smelting remains a significant challenge, directly hindering the production of high-grade, highly clean steels and causing stagnation in EAF technology. Therefore, improving steel cleanliness to meet the quality requirements of steel products is a key technology in EAF smelting.

[0003] To deeply remove impurities from molten steel, electric arc furnace steelmaking technologies such as clustered oxygen supply, bottom blowing agitation, and submerged powder injection have emerged. During the smelting process, oxygen is blown in while a large amount of slagging agents such as lime are added. Bottom blowing agitation assists in removing some impurities such as S, P, N, and H. However, this still does not meet the smelting standards for clean steel. After tapping, further refining is usually required for deeper deoxidation and desulfurization.

[0004] Currently, most steelmaking enterprises add deoxidizing materials such as aluminum blocks, ferrosilicon, calcium-barium silicon, silicon-manganese, and aluminum-barium-calcium silicon to the ladle during the steelmaking process for pre-deoxidation of the molten steel. They further desulfurize and control inclusions by adding slag-forming agents such as lime during the refining process or by using wire feeding operations. The main problem with these methods is that the influence of slag-steel interface kinetics leads to low efficiency and high cost, and also affects the control of inclusions in the steel, impacting subsequent production.

[0005] Chinese patent CN113832286A discloses a device and method for dephosphorizing by spraying powder at the tapping spout of a converter. Although the device can reduce the phosphorus content in the molten steel, it does not take into account the specific production conditions. Spraying powder at the tapping spout will shorten the life of the tapping spout, increase the risk of steel leakage, and require frequent replacement of the spray gun. The life of the spray gun is shortened under high temperature conditions, resulting in high maintenance costs. Therefore, it cannot be implemented in actual production.

[0006] Chinese patent CN207862386U discloses a pre-deoxidation device for injecting carbon powder into the tapping port of a converter. The device deoxidizes the steel by injecting carbon powder into the tapping steel stream through a carbon powder spray pipe inside the tapping port. However, this patented technology is greatly affected by the carbon powder injection speed, resulting in poor deoxidation effect, low practicality, and an inability to accurately control the relationship between deoxidation effect and carbon injection amount, which can easily lead to carbon increase in molten steel.

[0007] Chinese patent CN106048136A discloses an online powder injection deoxidation method and system for the steelmaking tapping process. It uses a spray gun to directly inject a carrier gas-deoxidation powder high-speed powder flow into the tapping steel stream to achieve online powder injection deoxidation during the steelmaking tapping process. However, during the implementation of this patented technology, the carbon powder comes into contact with the steel stream, causing a violent reaction that generates a large amount of dense smoke and flames, resulting in environmental pollution. At the same time, it affects the slag control in the later stage of tapping, leading to unqualified steel composition.

[0008] Chinese patent CN111635977A discloses a production equipment and process for a fully continuous ultra-short electric arc furnace steelmaking process. Although it involves injecting carbon powder, silicon powder, and other powders as reducing agents into the closed tapping chute for steel deoxidation, the furnace structure and the closed tapping chute are clearly integrally formed and not suitable for existing electric arc furnace tapping processes. This makes it impractical for actual production and limits its applicability. Furthermore, the amount of reducing agent powder injected into the closed tapping chute cannot be accurately controlled. Excessive injection of reducing agent powder leads to increased carbon content in the molten steel and excessive slag, affecting subsequent production. Insufficient injection, on the other hand, fails to achieve adequate deoxidation, impacting alloy yield. Summary of the Invention

[0009] The main objective of this invention is to address the technical problems existing in the electric arc furnace steelmaking process, such as the difficulty in deep removal of impurities like O, S, N, and H, the long refining process and high cost, low removal efficiency, and poor inclusion control. Therefore, a closed powder injection system and its usage method for the electric arc furnace steelmaking tapping process are proposed, capable of solving the aforementioned problems.

[0010] A closed powder injection system for the tapping process of an electric arc furnace steelmaking process is disclosed. The closed powder injection system includes an electric arc furnace, a closed powder injection device, a ladle, a powder injection system, a gas supply system, and a computer control system. The electric arc furnace is connected to the ladle through the closed powder injection device. The closed powder injection device is connected to the powder injection system and the gas supply system. The powder injection system is connected to the gas supply system. The computer control system is electrically connected to and controls the electric arc furnace, the closed powder injection device, the ladle, the powder injection system, and the gas supply system.

[0011] The electric arc furnace, the sealed powder injection device, and the ladle are arranged in a high-to-low configuration. The electric arc furnace outlet at the high position is connected to the ladle at the low position via the sealed chute of the sealed powder injection device. The gas supply system is connected to both the powder injection system and the sealed powder injection device. The top and bottom of the powder injection system are connected to the gas supply system. The outlet connection points of the powder injection system are located upstream and midstream of the pipeline connecting the electric arc furnace and the ladle via the sealed powder injection device. The computer control system is electrically connected to a lifting device for controlling the reduction and slag formation of molten steel, a moving trolley, an induction heating device, a first outlet valve, a first venting valve, a second venting valve, a second outlet valve, a third outlet valve, a conveyor belt, a gas source valve group, a first pressurizing valve, a second pressurizing valve, a first auxiliary blowing valve, and a second auxiliary blowing valve.

[0012] Optionally, the sealed powder spraying device comprises a mobile trolley, a lifting device, a sealed tapping chute, and an induction heating device; the lifting device on the mobile trolley supports the sealed tapping chute installed above the mobile trolley; the sealed tapping chute is arranged at different heights, with the inlet of the sealed tapping chute connected to the electric arc furnace at the higher position, and the outlet of the sealed tapping chute connected to the ladle at the lower position.

[0013] Optionally, the steel tapping sealed chute consists of a chute bottom and a shell, with matching connection dimensions; an induction heating device is provided on the outer side of the bottom of the steel tapping sealed chute, and the chute lining is constructed of refractory material; multiple holes for powder spraying and feeding are provided on the upper part of the shell of the steel tapping sealed chute, and powder spraying guns are installed in the holes, with the installation angles distributed at an angle of 30-150° along the vertical direction of the shell.

[0014] Optionally, the powder spraying system includes a reducing agent powder spraying device, a slag-forming agent powder spraying device, and an alloy feeding silo; the reducing agent powder spraying device and the slag-forming agent powder spraying device are respectively arranged above the sealed powder spraying device, and are connected to the powder spraying guns in the first opening and the second opening at the upstream and midstream positions of the sealed steel tapping chute through pipes; the alloy feeding silo is arranged above the sealed powder spraying device, and the alloy material is transported to the third opening at the downstream position of the sealed steel tapping chute by a conveyor belt.

[0015] Optionally, the gas supply system includes a jet gas source, a gas source valve group, a first pressurizing valve, a second pressurizing valve, a first auxiliary blowing valve, and a second auxiliary blowing valve.

[0016] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, comprising the following steps:

[0017] S1. Control the connection between the two ends of the closed tapping chute: When the computer control system receives the electrical signal of fast tapping of the electric arc furnace, it issues an instruction to control the moving trolley to move to the predetermined position below the tapping port of the electric arc furnace, and links the lifting device to connect the high end interface of the closed tapping chute with the tapping port of the electric arc furnace, and the low end interface with the ladle inlet.

[0018] S2. Types and amounts of injected materials: The computer control system receives information on the composition of molten steel and the composition of the target steel grade from the electric arc furnace, and uses a metallurgical model to calculate the required amount of deoxidation, desulfurization and alloy addition for the molten steel, thereby determining the type and amount of reducing agent, slag-forming agent and alloy addition to be injected.

[0019] S3. Completion of powder weighing and preparation for injection: After the powder injection system has completed the weighing of reducing powder, slag-forming powder and alloy, the powder to be injected is premixed and loaded into the powder injection tank. Select the appropriate injection gas, pressurize the powder injection tank, determine the powder injection flow rate and alloy addition speed, and wait for injection and feeding.

[0020] S4. Controlled Injection: When the electric arc furnace is smelting and tapping steel, the induction heating device below the sealed tapping chute is turned on to heat the molten steel; reducing powder is injected, and the powder comes into contact with the molten steel at an angle of 30-150° to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle; when the steel volume reaches 1 / 5 to 4 / 5, the alloy is added until the addition is complete.

[0021] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace, and link the moving trolley and lifting device back to the ready position to wait for the next heat of steel tapping.

[0022] Optionally, the reducing agent powder in S2 is any one or a mixture of two or more of carbon powder, coal powder, biomass powder, silicon powder, and ferrosilicon powder, and the powder particle diameter is 0.5-5 mm.

[0023] Optionally, the slag-forming agent powder in S2 is any one or a mixture of two or more of the following: lime powder, limestone powder, refined slag powder, dolomite powder, fluorite powder, ladle covering agent, synthetic slag, and desulfurizing agent, with a particle diameter of 0.5-2 mm.

[0024] Optionally, the injected gas in S3 can be any one or a mixture of two or more of nitrogen, argon, and carbon dioxide, selected according to the target steel grade; the gas flow rate is 50-10000 Nm³. 3 / h, powder spraying flow rate is 50-1000 kg / min, alloy addition rate is 100-500 kg / min.

[0025] Optionally, the method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process is applicable to 100-350t ultra-high power electric arc furnaces, horizontal charging electric arc furnaces, vertical electric arc furnaces, DC electric arc furnaces, or double-shell electric arc furnaces.

[0026] Optionally, the method of using the closed powder injection system in the electric arc furnace steelmaking process can reduce the oxygen content in the molten steel by more than 25%, reduce the amount of deoxidizer used per ton of steel by more than 8%, reduce the lime consumption per ton of steel by more than 1.0 kg, increase the alloy yield by more than 5%, reduce the consumption of alloy materials by more than 1 kg / t, and achieve a benefit of at least 15 yuan per ton of steel.

[0027] Optionally, the method of using the closed powder injection system in the electric arc furnace steelmaking process can reduce the oxygen content in the molten steel by up to 85%, reduce the amount of deoxidizer used per ton of steel by up to 50%, reduce the lime consumption per ton of steel by up to 5.5 kg, increase the alloy yield by up to 25%, reduce the consumption of alloy materials by up to 8.5 kg / t, and achieve a maximum benefit of 120 yuan per ton of steel.

[0028] The technical principle of this invention is as follows:

[0029] This invention constructs a sealed tapping channel between the electric arc furnace tapping port and the ladle, and installs a controllable powder injection device within this channel. This ensures that reducing agents, slag-forming agents, and alloy powders fully contact the molten steel during its flow, following a preset sequence, angle, and flow rate. This achieves deep deoxidation, desulfurization, and inclusion control of the molten steel during the tapping stage. Simultaneously, induction heating stabilizes the molten steel temperature, and computer metallurgical models are used to precisely calculate the amount of injected materials, automating and optimizing the injection process. This sealed powder injection combined with online precise control enhances the kinetics of the slag-steel interface reaction, improves the efficiency of impurity element removal, reduces the subsequent refining load, and thus improves the cleanliness of the molten steel.

[0030] The above technical solution has at least the following advantages compared with the existing technology:

[0031] The above-mentioned solution, proposed by the present invention, is a closed powder injection system and its usage method for the tapping process of electric arc furnace steelmaking. It can solve the technical problems existing in the prior art, such as the difficulty in deep removal of impurity elements such as O, S, N, and H in the electric arc furnace steelmaking process, the long refining process and high cost, the low removal efficiency and poor control of inclusions.

[0032] This invention solves the problems of high construction difficulty, rapid erosion of the steel outlet, high failure rate of the powder spraying equipment, and serious environmental pollution caused by the use of a mobile trolley powder spraying device in the prior art.

[0033] The closed powder spraying device provided by this invention can quickly complete operations such as powder spraying deoxidation, desulfurization, and alloying. It solves the problems of material adhering to the slag surface and insufficient reaction with molten steel in existing feeding operations, resulting in low material yield, substandard molten steel composition, and high production costs.

[0034] This invention uses a computer control system to automatically calculate the type and amount of sprayed material based on the composition of molten steel and the requirements of the target steel grade, and to precisely control the spraying sequence, spraying flow rate, spraying time and feeding rhythm, thereby achieving fully automated control of the powder spraying process.

[0035] This invention, by having the powder contact the molten steel at an angle of 30-150°, can significantly improve the contact angle between the powder and the molten steel, increase the contact area, enhance the interfacial reactivity, and improve the deoxidation and desulfurization efficiency.

[0036] The present invention begins to add alloy when the steel yield is between 1 / 5 and 4 / 5 of the total yield. This avoids burn-out caused by early addition or composition fluctuations caused by late addition, thereby improving alloy yield and ensuring stable and controllable steel composition.

[0037] In summary, compared with traditional impurity removal methods in electric arc furnace steelmaking, the method of this invention creatively controls the relationship between deoxidation and desulfurization effects and powder injection volume through system structure settings and usage selection. It reduces the amount of reducing agents, slagging agents, and alloys used, effectively stabilizes the composition of molten steel, and shortens the smelting production cycle. This method significantly reduces energy consumption, is green and low-carbon, has a short process, high production efficiency, wide raw material adaptability, and can co-produce high-value products, which is conducive to large-scale industrial production and widespread application. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a closed powder injection system for the tapping process of an electric arc furnace steelmaking process according to the present invention;

[0040] Figure 2 This is a schematic diagram of the cross-sectional structure of the closed powder injection system for the tapping process of an electric arc furnace steelmaking process according to the present invention.

[0041] Figure 3 This is a schematic diagram of the closed powder injection device structure of a closed powder injection system for the tapping process of an electric arc furnace steelmaking, according to the present invention.

[0042] Figure 4This is a schematic diagram of the powder injection system structure of a closed powder injection system for the tapping process of an electric arc furnace steelmaking, according to the present invention.

[0043] Figure 5 This is a schematic diagram of the gas supply system of a closed powder injection system for the tapping process of an electric arc furnace steelmaking according to the present invention.

[0044] Figure 6 This is a schematic diagram of the electrical connection of the computer control system of a closed powder injection system for the tapping process of an electric arc furnace steelmaking according to the present invention.

[0045] The annotations in the attached figures are explained as follows:

[0046] 1. Electric arc furnace; 2. Sealed powder injection device; 3. Steel ladle; 4. Powder injection system; 5. Gas supply system; 6. Computer control system; 201. Sealed tapping chute; 202. First opening; 203. Reducing agent powder injection gun; 204. Lifting device; 205. Moving trolley; 206. Slag-forming agent powder injection gun; 207. Induction heating device; 208. Second opening; 209. Third opening; 401. Reducing agent powder tank; 402. First outlet valve; 403. First vent valve; 404. Second vent valve; 405. Slag-forming agent powder tank; 406. Second outlet valve; 407. Alloy silo; 408. Third outlet valve; 409. Conveyor belt; 501. Injection gas source; 502. Gas source valve group; 503. First pressurization valve; 504. Second pressurization valve; 505. First auxiliary blowing valve; 506. Second auxiliary blowing valve. Detailed Implementation

[0047] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0048] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0049] Unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art. The terms "first," "second," and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely for the purpose of distinguishing corresponding components. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "high," "low," "up," and "down" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0050] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0051] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0052] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0053] See Figure 1 and Figure 6 As shown, a closed powder injection system for the tapping process of an electric arc furnace steelmaking process is disclosed. The closed powder injection system includes an electric arc furnace 1, a closed powder injection device 2, a ladle 3, a powder injection system 4, a gas supply system 5, and a computer control system 6. The electric arc furnace 1 is connected to the ladle 3 through the closed powder injection device 2. The closed powder injection device 2 is connected to the powder injection system 4 and the gas supply system 5. The powder injection system 4 is connected to the gas supply system 5. The computer control system 6 is electrically connected to and controls the electric arc furnace 1, the closed powder injection device 2, the ladle 3, the powder injection system 4, and the gas supply system 5.

[0054] The electric arc furnace 1, the sealed powder injection device 2, and the ladle 3 are arranged in a descending order. The outlet of the electric arc furnace 1, located at a higher position, is connected to the ladle 3, located at a lower position, through the sealed discharge chute 201 of the sealed powder injection device 2. The gas supply system 5 is connected to both the powder injection system 4 and the sealed powder injection device 2. The top and bottom of the powder injection system 4 are connected to the gas supply system 5. The outlet connection points of the powder injection system 4 are located upstream and midstream of the pipeline connecting the electric arc furnace 1 and the ladle 3 in the sealed powder injection device 2, respectively. Location; The computer control system 6 is electrically connected to a lifting device 204 for controlling the reduction and slag formation of molten steel, a moving trolley 205, an induction heating device 207, a first outlet valve 402, a first venting valve 403, a second venting valve 404, a second outlet valve 406, a third outlet valve 408, a conveyor belt 409, an air source valve group 502, a first pressurizing valve 503, a second pressurizing valve 504, a first blowing valve 505, and a second blowing valve 506.

[0055] Specifically, see Figure 2 and Figure 3 As shown, the sealed powder spraying device 2 comprises a mobile trolley 205, a lifting device 204, a sealed tapping chute 201, and an induction heating device 207. The lifting device 204 installed on the mobile trolley 205 supports the sealed tapping chute 201, which is installed above the mobile trolley 205. The sealed tapping chute 201 is arranged at different heights, with the inlet of the sealed tapping chute 201 connected to the electric arc furnace 1 at the higher position and the outlet of the sealed tapping chute 201 connected to the ladle 3 at the lower position.

[0056] Specifically, see Figure 2 and Figure 3 As shown, the steel tapping sealed chute 201 consists of a chute bottom and a shell, with matching connection dimensions; an induction heating device 207 is provided on the outer side of the bottom of the steel tapping sealed chute 201, and the chute lining is made of refractory material; multiple holes for powder spraying and feeding are provided on the upper part of the shell of the steel tapping sealed chute 201, and powder spraying guns are installed in the holes, with the installation angles distributed at an angle of 30-150° along the vertical direction of the shell.

[0057] Specifically, see Figure 1 , Figure 4 and Figure 6As shown, the powder spraying system 4 includes a reducing agent powder tank 401, a slag-forming agent powder tank 405, and an alloy silo 407. The reducing agent powder tank 401 is connected to the first outlet valve 402, and is connected to the powder spraying gun 203 in the first opening 202 of the steel tapping sealed chute 201 through a feeding pipe. It is also connected to the first pressurization valve 503 of the air supply system 5 above, and is also provided with a first vent valve 403. The slag-forming agent powder tank 405 is connected to the second outlet valve 406, and is connected to the powder spraying gun 206 in the second opening 208 of the steel tapping sealed chute 201 through a feeding pipe. It is also connected to the second pressurization valve 504 of the air supply system 5 above, and is also provided with a second vent valve 404. The alloy silo 407 is arranged above the sealed powder spraying device 2. The alloy material is discharged through the third outlet valve 408 to the conveyor belt 409 and transported to the third opening 209 of the steel tapping sealed chute 201.

[0058] Specifically, the air supply system 5 includes a jet air source 501, an air source valve group 502, a first pressurization valve 503, a second pressurization valve 504, a first auxiliary blowing valve 505, and a second auxiliary blowing valve 506.

[0059] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, comprising the following steps:

[0060] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0061] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the composition of the target steel grade from the electric arc furnace 1, and uses a metallurgical model to calculate the required amount of deoxidation, desulfurization and alloy addition for the molten steel, thereby determining the type and amount of reducing agent, slag-forming agent and alloy addition to be injected.

[0062] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 has completed the weighing of reducing powder, slag-forming powder and alloy, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. Select the appropriate injection gas, pressurize the reducing agent powder tank 401 and the slag-forming agent powder tank 405, determine the powder injection flow rate and alloy addition speed, and wait for injection and feeding.

[0063] S4. Controlled Injection: The electric arc furnace 1 smelts and taps steel. The induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel. The reducing powder is injected and comes into contact with the molten steel at an angle of 30-150° to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206. The slag-forming powder is injected and comes into full contact with the molten steel to remove impurities before flowing into the ladle 3. When the tapping amount is 1 / 5 to 4 / 5, the alloy is added until the addition is complete.

[0064] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0065] Specifically, the reducing agent powder in S2 is any one or a mixture of two or more of the following: carbon powder, coal powder, biomass powder, silicon powder, and ferrosilicon powder, with a particle diameter of 0.5-5 mm.

[0066] Specifically, the slag-forming agent powder in S2 is any one or a mixture of two or more of the following: lime powder, limestone powder, refined slag powder, dolomite powder, fluorite powder, ladle covering agent, synthetic slag, and desulfurizing agent, with a particle diameter of 0.5-2 mm.

[0067] Specifically, the injected gas in S3 is any one or a mixture of two or more of nitrogen, argon, and carbon dioxide, selected according to the target steel grade; the gas flow rate is 50-10000 Nm³. 3 / h, powder spraying flow rate is 50-1000 kg / min, alloy addition rate is 100-500 kg / min.

[0068] In particular, the method of using the closed powder injection system in the steelmaking and tapping process of the electric arc furnace is applicable to ultra-high power electric arc furnaces of 100-350t, horizontal charging electric arc furnaces, vertical electric arc furnaces, DC electric arc furnaces, or double-shell electric arc furnaces.

[0069] The method of using the closed powder injection system in the electric arc furnace steelmaking process is particularly effective. It can reduce the oxygen content in the molten steel by more than 25%, reduce the amount of deoxidizer used per ton of steel by more than 8%, reduce the lime consumption per ton of steel by more than 1.0 kg, increase the alloy yield by more than 5%, and reduce the consumption of alloy materials by more than 1 kg / t, thereby achieving a benefit of at least 15 yuan per ton of steel.

[0070] The method of using the closed powder injection system in the electric arc furnace steelmaking process is particularly effective. It can reduce the oxygen content in molten steel by up to 85%, reduce the amount of deoxidizer used per ton of steel by up to 50%, reduce the lime consumption per ton of steel by up to 5.5 kg, increase the alloy yield by up to 25%, and reduce the consumption of alloy materials by up to 8.5 kg / t, achieving a maximum benefit of 120 yuan per ton of steel.

[0071] Example 1

[0072] A method for using a closed powder injection system in the tapping process of an electric arc furnace steelmaking process, as described above, is applied to a 100t horizontally charged electric arc furnace for smelting CrMo steel, with 110t of scrap steel added as smelting raw materials. The target molten steel is required to have C 0.04-0.08%, O≤800ppm, S≤0.008%, and the tapping temperature of the electric arc furnace is 1630-1650℃. The method specifically includes the following steps:

[0073] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0074] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade (C 0.06%, O≤1100ppm, S≤0.01%) from the electric arc furnace 1. Using the metallurgical model, it calculates that: the deoxidation amount is 300ppm, and 2kg of carbon powder is injected per ton of molten steel, for a total of 200kg of carbon powder; the desulfurization amount is 200ppm, and 1.5kg of lime powder is injected per ton of molten steel, for a total of 150kg of lime powder; 1100kg of high-carbon ferrochrome and 300kg of ferrosilicon are added to the alloy.

[0075] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 600 Nm³. 3 / h, powder injection flow rate is 80kg / min, alloy addition rate is 150kg / min, waiting for spraying and feeding;

[0076] S4. Controlled injection: When the electric arc furnace 1 smelts and taps steel, the induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel; the reducing powder is injected, and the powder comes into contact with the molten steel at a 120° angle to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle 3; when the steel tapping amount reaches 1 / 3, the alloy is added, and the addition is controlled until the steel tapping amount reaches 2 / 3, until the addition is completed;

[0077] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0078] The method of using the closed powder injection system in the electric arc furnace steelmaking process of this embodiment can reduce the oxygen content in the molten steel by more than 50%, reduce the amount of deoxidizer used per ton of steel by more than 18%, reduce the lime consumption per ton of steel by more than 20%, increase the alloy yield by 5%, reduce the consumption of alloy materials by more than 2 kg / t, and achieve a benefit of more than 8 yuan per ton of steel.

[0079] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in molten steel by up to 55%, reduce the amount of deoxidizer used per ton of steel by up to 15%, reduce the lime consumption per ton of steel by up to 1.35 kg, increase the alloy yield by up to 9%, reduce the alloy material consumption by up to 2.5 kg / t, and achieve a maximum benefit of 40 yuan per ton of steel.

[0080] Example 2

[0081] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, is applied to a 90t ultra-high power electric arc furnace for smelting low-nitrogen alloy steels, using 20% ​​molten iron and 80% scrap steel as smelting raw materials. The target molten steel is required to have C 0.03-0.07%, O≤600ppm, N≤0.0015%, S≤0.009%, and the electric arc furnace tapping temperature is 1620-1650℃. The method specifically includes the following steps:

[0082] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0083] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade (C 0.07%, O≤950ppm, S≤0.012%) from the electric arc furnace 1. Using the metallurgical model, it calculates that: the deoxidation amount is 350ppm, and 2.2kg of biomass char powder is injected per ton of molten steel, for a total of 198kg of biomass char powder; the desulfurization amount is 300ppm, and 3kg of lime powder + 1kg of refining slag + 1kg of dolomite powder is injected per ton of molten steel, for a total of 450kg of slag-forming agent powder is injected; 200kg of ferromanganese, 500kg of low-carbon ferrochrome and 150kg of ferrosilicon are added to the alloy.

[0084] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 800 Nm³. 3 / h, powder spraying flow rate is 100kg / min, alloy addition rate is 250kg / min, waiting for spraying and feeding;

[0085] S4. Controlled injection: When the electric arc furnace 1 smelts and taps steel, the induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel; the reducing powder is injected, and the powder comes into contact with the molten steel at an angle of 110° to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle 3; when the steel tapping amount reaches 1 / 5, the alloy is added, and the addition is controlled until the steel tapping amount reaches 3 / 5, until the addition is completed;

[0086] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0087] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in the molten steel by more than 30%, the nitrogen content by 25 ppm, reduce the amount of deoxidizer used per ton of steel by more than 2.3 kg / t, reduce the consumption of slag-forming agent per ton of steel by more than 3 kg, increase the alloy yield by 9.1%, and achieve a profit of more than 25 yuan per ton of steel.

[0088] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in molten steel by up to 39%, reduce the amount of deoxidizer used per ton of steel by up to 22%, reduce the lime consumption per ton of steel by up to 3.5 kg, increase the alloy yield by up to 13%, reduce the consumption of alloy materials by up to 2.87 kg / t, and achieve a maximum benefit of 52 yuan per ton of steel.

[0089] Example 3

[0090] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, is applied to a 150t vertical electric arc furnace for smelting low-nitrogen alloy steels, using 100% scrap steel as the smelting raw material. The target molten steel is required to have C 0.05-0.13%, O≤750ppm, N≤0.0016%, S≤0.01%, and the electric arc furnace tapping temperature is 1600-1630℃. The method specifically includes the following steps:

[0091] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0092] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade (C 0.08%, O≤550ppm, S≤0.008%) from the electric arc furnace 1. Using the metallurgical model, it calculates that: the deoxidation amount is 200ppm, and 1.2kg of biomass char powder is injected per ton of molten steel, for a total of 180kg of biomass char powder; the desulfurization amount is 300ppm, and 2.5kg of lime powder + 1.5kg of refining slag + 1kg of dolomite powder is injected per ton of molten steel, for a total of 750kg of slag-forming agent powder is injected; 120kg of ferromanganese, 200kg of low-carbon ferrochrome and 80kg of ferrosilicon are added to the alloy.

[0093] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 1200 Nm³. 3 / h, powder injection flow rate is 120kg / min, alloy addition rate is 220kg / min, waiting for spraying and feeding;

[0094] S4. Controlled Injection: When the electric arc furnace 1 smelts and taps steel, the induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel; the reducing powder is injected, and the powder comes into contact with the molten steel at a 100° angle to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle 3; when the steel tapping amount reaches 1 / 2, the alloy is added, and the addition is controlled until the steel tapping amount reaches 4 / 5, until the addition is completed;

[0095] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0096] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in the molten steel by more than 26%, the nitrogen content by 29 ppm, reduce the amount of deoxidizer used per ton of steel by more than 1.83 kg / t, reduce the consumption of slagging agent per ton of steel by more than 5.5 kg, increase the alloy yield by up to 3.17 kg / t, and achieve a profit of more than 29 yuan per ton of steel.

[0097] The method of using the closed powder injection system in the electric arc furnace steelmaking process of this embodiment can reduce the oxygen content in molten steel by up to 37%, reduce the amount of deoxidizer used per ton of steel by up to 33%, reduce the lime consumption per ton of steel by up to 3.5 kg, increase the alloy yield by up to 11.5%, reduce the consumption of alloy materials by up to 1.8 kg / t, and achieve a maximum benefit of 43 yuan per ton of steel.

[0098] Example 4

[0099] A method for using a closed powder injection system in the tapping process of an electric arc furnace steelmaking process, as described above, is applied to a 100t horizontally charged electric arc furnace for smelting ultra-low carbon steel grades, using 20% ​​pig iron and 80% scrap steel as smelting raw materials. The target molten steel is required to have C 0.05-0.15%, O≤950ppm, N≤0.0020%, S≤0.012%, and a tapping temperature of 1600-1650℃. The method specifically includes the following steps:

[0100] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0101] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade from the electric arc furnace 1 (C 0.05%, O≤620ppm, S≤0.007%). Using a metallurgical model, it calculates that: the deoxidation amount is 330ppm, and 0.8kg of biomass char powder is injected per ton of molten steel, for a total of 80kg of biomass char powder; the desulfurization amount is 500ppm, and 6.5kg of lime powder + 4kg of refining slag + 1.5kg of dolomite powder is injected per ton of molten steel, for a total of 1200kg of slag-forming agent powder is injected; 145kg of ferromanganese, 100kg of low-carbon ferrochrome and 110kg of ferrosilicon are added to the alloy.

[0102] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 1000 Nm³. 3 / h, powder injection flow rate is 150kg / min, alloy addition rate is 120kg / min, waiting for spraying and feeding;

[0103] S4. Controlled injection: When the electric arc furnace 1 smelts and taps steel, the induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel; the reducing powder is injected, and the powder comes into contact with the molten steel at a 135° angle to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle 3; when the steel tapping amount reaches 1 / 5, the alloy is added, and the addition is controlled until the steel tapping amount reaches 4 / 5, until the addition is completed.

[0104] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0105] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in the molten steel by more than 34.7%, the nitrogen content by 30 ppm, reduce the amount of deoxidizer used per ton of steel by more than 2.55 kg / t, reduce the consumption of slagging agent per ton of steel by more than 3.5 kg, increase the alloy yield by up to 7.5 kg / t, and achieve a profit of more than 49 yuan per ton of steel.

[0106] The method of using the closed powder injection system in the electric arc furnace steelmaking process of this embodiment can reduce the oxygen content in molten steel by up to 56%, reduce the amount of deoxidizer used per ton of steel by up to 43%, reduce the lime consumption per ton of steel by up to 5.5 kg, increase the alloy yield by up to 23.5%, reduce the consumption of alloy materials by up to 8.5 kg / t, and achieve a maximum benefit of 107 yuan per ton of steel.

[0107] Example 5

[0108] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, is applied to a 60t DC electric arc furnace for smelting stainless steel, using 100% scrap steel as the smelting raw material. The target molten steel is required to have C ≤0.1%, O ≤780ppm, N ≤0.003%, S ≤0.03%, and the electric arc furnace tapping temperature is 1650-1670℃. The method specifically includes the following steps:

[0109] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0110] S2. Types and amounts of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade from the electric arc furnace 1 (C 0.03%, O≤500ppm, S≤0.01%, Si≤1%, Mn≤2%, 16%≤Cr≤18%). Using the metallurgical model, it calculates that: the deoxidation amount is 280ppm, and 2.0kg of biomass char powder is injected per ton of molten steel, for a total of 120kg of biomass char powder; the desulfurization amount is 2000ppm, and 6kg of lime powder + 3kg of refining slag + 1kg of dolomite powder is injected per ton of molten steel, for a total of 600kg of slag-forming agent powder is injected; 220kg of ferromanganese, 350kg of low-carbon ferrochrome and 150kg of ferrosilicon are added to the alloy.

[0111] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 1300 Nm³. 3 / h, powder injection flow rate is 130kg / min, alloy addition rate is 180kg / min, waiting for spraying and feeding;

[0112] S4. Controlled injection: When the electric arc furnace 1 smelts and taps steel, the induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel; the reducing powder is injected, and the powder comes into contact with the molten steel at an 87° angle to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206, and the slag-forming powder is injected. After fully contacting the molten steel to remove impurities, it flows into the ladle 3; when the steel tapping amount reaches 1 / 5, the alloy is added, and the addition is controlled until the steel tapping amount reaches 2 / 3, until the addition is completed;

[0113] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0114] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in the molten steel by more than 35%, the nitrogen content by 49 ppm, reduce the amount of deoxidizer used per ton of steel by more than 4.2 kg / t, reduce the consumption of slagging agent per ton of steel by more than 4.5 kg, increase the alloy yield by up to 2.5 kg / t, and achieve a profit of more than 25 yuan per ton of steel.

[0115] The method of using the closed powder injection system in the electric arc furnace steelmaking process of this embodiment can reduce the oxygen content in molten steel by up to 77%, reduce the amount of deoxidizer used per ton of steel by up to 43%, reduce the lime consumption per ton of steel by up to 5 kg, increase the alloy yield by up to 25%, reduce the alloy material consumption by up to 8.5 kg / t, and achieve a maximum benefit of 120 yuan per ton of steel.

[0116] Example 6

[0117] A method for using a closed powder injection system during the tapping process of an electric arc furnace steelmaking process, as described above, is applied to an 80t double-shell electric arc furnace for smelting ordinary alloy steels, using 50% molten iron and 50% scrap steel as smelting raw materials. The target molten steel composition is required to be C≤0.1%, O≤750ppm, N≤0.003%, S≤0.01%, and the tapping temperature of the electric arc furnace is 1615-1635℃. The method specifically includes the following steps:

[0118] S1. Controlling the connection between the two ends of the closed tapping chute: When the computer control system 6 receives the electrical signal of the electric arc furnace 1 for fast tapping, it issues an instruction to control the moving trolley 205 to travel to a predetermined position below the tapping port of the electric arc furnace 1, and links the lifting device 204 to connect the high end interface of the closed tapping chute 201 with the tapping port of the electric arc furnace 1 and the low end interface with the inlet of the ladle 3.

[0119] S2. Types and dosages of injected materials: The computer control system 6 receives information on the composition of molten steel and the target steel grade (C 0.05%, O≤620ppm, S≤0.008%) from the electric arc furnace 1. Using the metallurgical model, it calculates that: the deoxidation amount is 130ppm, and 1.3kg of biomass char powder is injected per ton of molten steel, for a total of 104kg of biomass char powder; the desulfurization amount is 200ppm, and 3.5kg of lime powder + 2.7kg of refining slag + 0.8kg of dolomite powder is injected per ton of molten steel, for a total of 504kg of slag-forming agent powder is injected; 80kg of ferromanganese, 50kg of low-carbon ferrochrome, and 50kg of ferrosilicon are added to the alloy.

[0120] S3. Completion of powder weighing and preparation for injection: After the powder injection system 4 completes the weighing of reducing powder, slag-forming powder, and alloy materials, the pre-mixed powder is loaded into the reducing agent powder tank 401 and the slag-forming agent powder tank 405 respectively. A suitable injection gas is selected, and the reducing agent powder tank 401 and the slag-forming agent powder tank 405 are pressurized, with the gas flow rate determined to be 800 Nm³. 3 / h, powder injection flow rate is 110kg / min, alloy addition rate is 180kg / min, waiting for spraying and feeding;

[0121] S4. Controlled Injection: The electric arc furnace 1 smelts and taps steel. The induction heating device 207 below the sealed tapping chute 201 is turned on to heat the molten steel. The reducing powder is injected and comes into contact with the molten steel at a 120° angle to begin deoxidation. After deoxidation, the molten steel flows directly below the slag-forming agent injection gun 206. The slag-forming powder is injected and comes into full contact with the molten steel to remove impurities before flowing into the ladle 3. When the steel tapping amount reaches 1 / 5, the alloy is added. The addition is controlled until the steel tapping amount reaches 4 / 5, until the addition is completed.

[0122] S5. Control of steel tapping completion: After steel tapping is completed, close the powder injection valve and the feeding valve, straighten the electric arc furnace 1, and link the moving trolley 205 and the lifting device 204 back to the ready position to wait for the next heat of steel tapping.

[0123] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in the molten steel by more than 32%, the nitrogen content by 23.5 ppm, reduce the amount of deoxidizer used per ton of steel by more than 1.78 kg / t, reduce the consumption of slag-forming agent per ton of steel by more than 2.3 kg, increase the alloy yield by up to 1.1 kg / t, and achieve a profit of more than 30 yuan per ton of steel.

[0124] The method of using the closed powder injection system in the electric arc furnace steelmaking and tapping process of this embodiment can reduce the oxygen content in molten steel by up to 43%, reduce the amount of deoxidizer used per ton of steel by up to 37%, reduce the lime consumption per ton of steel by up to 3.5 kg, increase the alloy yield by up to 18.2%, reduce the consumption of alloy materials by up to 1.8 kg / t, and achieve a maximum benefit of 57 yuan per ton of steel.

[0125] The above-mentioned solution, proposed by the present invention, is a closed powder injection system and its usage method for the tapping process of electric arc furnace steelmaking. It can solve the technical problems existing in the prior art, such as the difficulty in deep removal of impurity elements such as O, S, N, and H in the electric arc furnace steelmaking process, the long refining process and high cost, the low removal efficiency and poor control of inclusions.

[0126] This invention solves the problems of high construction difficulty, rapid erosion of the steel outlet, high failure rate of the powder spraying equipment, and serious environmental pollution caused by the use of a mobile trolley powder spraying device in the prior art.

[0127] The closed powder spraying device provided by this invention can quickly complete operations such as powder spraying deoxidation, desulfurization, and alloying. It solves the problems of material adhering to the slag surface and insufficient reaction with molten steel in existing feeding operations, resulting in low material yield, substandard molten steel composition, and high production costs.

[0128] This invention uses a computer control system to automatically calculate the type and amount of sprayed material based on the composition of molten steel and the requirements of the target steel grade, and to precisely control the spraying sequence, spraying flow rate, spraying time and feeding rhythm, thereby achieving fully automated control of the powder spraying process.

[0129] This invention, by having the powder contact the molten steel at an angle of 30-150°, can significantly improve the contact angle between the powder and the molten steel, increase the contact area, enhance the interfacial reactivity, and improve the deoxidation and desulfurization efficiency.

[0130] The present invention begins to add alloy when the steel yield is between 1 / 5 and 4 / 5 of the total yield. This avoids burn-out caused by early addition or composition fluctuations caused by late addition, thereby improving alloy yield and ensuring stable and controllable steel composition.

[0131] In summary, compared with traditional impurity removal methods in electric arc furnace steelmaking, the method of this invention creatively controls the relationship between deoxidation and desulfurization effects and powder injection volume through system structure settings and usage selection. It reduces the amount of reducing agents, slagging agents, and alloys used, effectively stabilizes the composition of molten steel, and shortens the smelting production cycle. This method significantly reduces energy consumption, is green and low-carbon, has a short process, high production efficiency, wide raw material adaptability, and can co-produce high-value products, which is conducive to large-scale industrial production and widespread application.

[0132] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0133] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0134] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0135] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An arc furnace steelmaking tapping process closed dusting system, characterized in that, The arc furnace steel tapping process closed powder spraying system comprises an arc furnace, a closed powder spraying device, a ladle, a powder spraying system, a gas supply system and a computer control system; the arc furnace is communicated with the ladle through the closed powder spraying device, the closed powder spraying device is communicated with the powder spraying system and the gas supply system, the powder spraying system is communicated with the gas supply system, and the computer control system is electrically connected with the arc furnace, the closed powder spraying device, the ladle, the powder spraying system and the gas supply system for control. The arc furnace, the closed powder spraying device and the ladle are distributed from high to low, the arc furnace tapping opening in the high position is connected with the ladle in the low position through the tapping closed chute of the closed powder spraying device, the gas supply system is communicated with the powder spraying system and the closed powder spraying device at the same time, the top end and the bottom end of the powder spraying system are communicated with the gas supply system, the outlet communication points of the powder spraying system are respectively located at the upstream position and the midstream position of the first opening and the second opening of the closed powder spraying device communicated with the arc furnace and the ladle pipeline, and the computer control system is electrically connected with the lifting device for controlling the molten steel reduction and slagging, the moving trolley, the induction heating device, the first outlet valve, the first diffusion valve, the second diffusion valve, the second outlet valve, the third outlet valve, the conveying belt, the gas source valve group, the first pressure charging valve, the second pressure charging valve, the first blowing aid valve and the second blowing aid valve.

2. The closed dusting system for the steelmaking tapping process of the electric arc furnace according to claim 1, characterized in that, The closed powder spraying device comprises a moving trolley, a lifting device, a tapping closed chute and an induction heating device; the lifting device arranged on the moving trolley supports the tapping closed chute installed above the moving trolley; the tapping closed chute is arranged in high and low positions, the inlet of the tapping closed chute is communicated with the arc furnace in the high position, and the outlet of the tapping closed chute is communicated with the ladle in the low position.

3. The closed dusting system for the steelmaking process in the electric arc furnace according to claim 1, characterized in that, The tapping closed chute is composed of a chute bottom and a shell, and the connection sizes are matched with each other; the tapping closed chute bottom is provided with an induction heating device outside, and the chute lining is built by refractory materials; a plurality of holes for powder spraying and material charging are respectively arranged above the shell of the tapping closed chute, powder spraying guns are installed in the holes, and the installation angles are distributed at an angle of 30-150° along the vertical direction of the shell.

4. The closed dusting system for the steelmaking tapping process of the electric arc furnace according to claim 1, characterized in that, The powder spraying system comprises a reducing agent powder spraying device, a slagging agent powder spraying device and an alloy charging bin; the reducing agent powder spraying device and the slagging agent powder spraying device are arranged above the closed powder spraying device and are respectively communicated with the powder spraying guns in the first opening and the second opening of the upstream position and the midstream position of the tapping closed chute through pipelines; the alloy charging bin is arranged above the closed powder spraying device, and the alloy material is conveyed to the third opening of the downstream position of the tapping closed chute through the conveying belt.

5. A method of using a closed powder injection system for the steel tapping process of an electric arc furnace as claimed in any one of the claims 1-4, characterized in that, The use method of the arc furnace steel tapping process closed powder spraying system comprises the following steps: S1, controlling the communication of both ends of the tapping closed chute: when the computer control system receives the electric signal of the arc furnace smelting fast tapping, the moving trolley is controlled to travel to the predetermined position below the arc furnace tapping opening, the lifting device is controlled to make the high end interface of the tapping closed chute communicated with the arc furnace tapping opening and the low end interface communicated with the ladle inlet. S2, the type and amount of the sprayed material: the computer control system receives information from the arc furnace smelting steel composition and target steel composition, calculates the required deoxidation amount, desulfurization amount and alloy addition amount of the steel using metallurgical model, so as to determine the type and amount of the sprayed reducing agent, the type and amount of the slag forming agent and the type and amount of the added alloy; S3, the completion of the weighing and preparation of the sprayed powder: after the weighing of the reducing powder, the weighing of the slag forming powder and the weighing of the alloy are completed by the powder spraying system, the sprayed powder is pre-mixed and loaded into the powder spraying tank, the appropriate spraying gas is selected, the powder spraying tank is pressurized, the powder spraying flow and the alloy addition speed are determined, and the spraying and feeding are waited for; S4, the control of the spraying: the arc furnace is smelted, the inductive heating device below the tapping closed chute is opened to heat the molten steel, the reducing powder starts to be sprayed, the powder contacts the molten steel at an angle of 30-150° to start deoxidation, after the deoxidation, the molten steel flows through the slag forming powder gun directly below, the slag forming powder starts to be sprayed, and after the impurity elements are removed by fully contacting the molten steel, the molten steel flows into the ladle; when the ratio of the tapped steel is 1 / 5 to 4 / 5, the alloy starts to be added until the feeding is completed; S5, the control of the end of the tapping: after the tapping is completed, the powder spraying valve and the feeding valve are closed, the arc furnace is shaken to the right position, the moving trolley and the lifting device are returned to the preparation position by the linkage control, and the next tapping is waited for.

6. The method of using an arc furnace steelmaking tapping process closed dusting system according to claim 5, characterized in that, The reducing agent powder in S2 is any one or a mixture of two or more of carbon powder, coal powder, biomass powder, silicon powder and silicon-iron powder, and the particle diameter of the powder is 0.5-5mm.

7. The method of using an arc furnace steelmaking tapping process dusting system according to claim 5, wherein, The slag forming agent powder in S2 is any one or a mixture of two or more of lime powder, limestone powder, refining slag powder, dolomite powder, fluorite powder, ladle covering agent, synthetic slag and desulfurizing agent, and the particle diameter of the powder is 0.5-2mm.

8. The method of using an arc furnace steelmaking tapping process dusting system according to claim 5, wherein, The blowing gas in S3 is any one or mixture of two or more of nitrogen, argon and carbon dioxide, which is selected according to the target steel grade; the gas flow is 50-10000 Nm 3 / h, the powder flow is 50-1000 kg / min, and the alloy addition speed is 100-500 kg / min.

9. The method of using an arc furnace steelmaking tapping process dusting system according to claim 5, wherein, The use method of the arc furnace steel smelting and tapping process closed powder spraying system is suitable for 100-350t super high power arc furnaces, horizontal feeding arc furnaces, vertical arc furnaces, direct current arc furnaces or double furnace shell arc furnaces.

10. The method of using an arc furnace steelmaking tapping process dusting system according to claim 5, wherein, The use method of the arc furnace steel smelting and tapping process closed powder spraying system can reduce the oxygen content in the molten steel by more than 25%, reduce the deoxidizing agent consumption per ton of steel by more than 8%, reduce the lime consumption per ton of steel by more than 1.0kg, increase the alloy yield by more than 5%, reduce the alloy consumption by more than 1kg / t, and realize a benefit of at least 15 yuan per ton of steel.

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