A control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking

Abstract

The invention provides a control method for reducing carbon-oxygen accumulation in electric arc furnace steelmaking, which relates to the field of steel smelting, comprising: 1) determining the amount of steel retained according to a steel retention system, adding raw scrap steel and raw molten iron into the electric arc furnace, and controlling the carbon content of the raw materials in the electric arc furnace to be 1.6-2.5%; 2) performing smelting oxygen blowing according to a preset power supply system and an oxygen supply system, adopting electromagnetic stirring at the furnace bottom during the smelting process, slagging according to a preset slag making system after the smelting reaches a preset target, and controlling the basicity of the steel slag to be 2.0-2.5 during the slag making process; 3) sampling and measuring the molten steel in the electric arc furnace, controlling the smelting end point temperature to be 1590-1610°C, and performing EBT tapping; the invention can effectively reduce the carbon-oxygen accumulation value of the molten steel by optimizing the steel retention system, the power supply system, the oxygen supply system, the slag making system, and designing the carbon content and power stirring.

Description

Technical Field

[0001] The invention relates to the technical field of steel smelting, and in particular to a control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking. Background Art

[0002] Compared with the converter process, the production cost of electric arc furnace steelmaking is relatively high. In terms of carbon-oxygen product alone, the average carbon-oxygen product of the electric arc furnace is between 0.0032-0.0045, and the average carbon-oxygen product of the converter is below 0.0020. There is a huge gap between the two. The high oxygen content in the molten steel during steelmaking will inevitably result in low metal yield. Therefore, it is necessary to solve the technical problem of high carbon-oxygen product in the electric arc furnace.

[0003] Prior art, such as the method for reducing carbon and oxygen accumulation at the end of an electric arc furnace disclosed in patent application CN111635978A, comprises the following steps: 1) 10t of steel is retained from the previous smelting, lime and scrap steel are added into the furnace to melt the scrap steel, carbon powder and slag-removing agent are added during the melting process, oxygen is blown into the furnace at the same time, and ferrosilicon is added after the scrap steel is completely melted; 2) bottom gas is blown during the smelting process, N2 is used during the melting period, and CO2 is used during the oxidation period; 3) the basicity of the slag is controlled at 2.8-3.2 during the slag-making process, and the temperature at the end of the smelting is controlled at 1650-1680°C. Through the above steps, the method can indeed achieve the effect of reducing the carbon-oxygen accumulation at the end point of electric arc furnace smelting, but its steel-out temperature is relatively high, reaching 1650-1680°C, which will increase the power consumption of electric arc furnace smelting and cause the power consumption cost to rise; in addition, although ferrosilicon is added after the scrap steel material is completely melted, the carbon-oxygen accumulation is reduced, but the alloy cost is increased due to the use of ferrosilicon; and, during the smelting process, bottom gas is blown. At present, the life of the bottom-blown bricks of the electric arc furnace is short, and the bottom blowing technology is still immature, which poses certain safety hazards.

[0004] Therefore, the prior art lacks a control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking that is cost-controllable, has mature technology, and has low safety hazards. Summary of the invention

[0005] The purpose of the present invention is to provide a control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking. When deoxidizing alloys such as ferrosilicon are not used in the electric arc furnace, the power supply and oxygen supply system of the smelting process are optimized to achieve power-oxygen balance to achieve maximum smelting of foamed slag; the bottom of the electric arc furnace uses electromagnetic stirring technology to control the steel tapping temperature, thereby reducing the carbon and oxygen accumulation in electric arc furnace steelmaking.

[0006] To achieve the above object, the present invention proposes the following technical solution: a control method for reducing carbon-oxygen accumulation in electric arc furnace steelmaking, comprising the following steps:

[0007] 1) The amount of steel retained in the electric arc furnace is determined according to the steel retention system. The raw scrap steel added to the electric arc furnace is added to the raw molten iron into the electric arc furnace through the rear chute after power is turned on and melted, so that the carbon content of the raw materials in the electric arc furnace is controlled to 1.6-2.5%;

[0008] 2) Smelting oxygen blowing is carried out according to the preset power supply system and oxygen supply system. Electromagnetic stirring is adopted at the bottom of the furnace during the smelting process. The raw materials in the electric arc furnace undergo a melting period and an oxidation period in sequence during the smelting oxygen blowing process. After the temperature reaches the preset target, slag is made according to the preset slag making system. During the slag making process, the basicity of the steel slag is controlled to be 2.0-2.5;

[0009] 3) After sampling the molten steel in the electric arc furnace, the temperature is measured and the oxygen is determined. The smelting end temperature is controlled at 1590-1610℃, and EBT tapping is carried out after the tapping conditions are met.

[0010] Furthermore, the power supply system is the selection of power supply gears for the electric arc furnace, including: the smelting arc starting gear is controlled at gear 8, the drilling process uses gears 10-13, the smelting stage uses gear 15, the melting stage uses gears 10-12 after melting, and the arc is exposed at the end of smelting, and the gear is adjusted downward to gears 4-5;

[0011] The oxygen supply system is to set the oxygen supply mode of the furnace wall oxygen lance and the furnace door oxygen lance;

[0012] The oxygen supply modes of the furnace wall oxygen lance include burner mode, low oxygen mode, medium oxygen mode, high oxygen mode and holding mode; at the beginning of smelting, the furnace wall oxygen lance adopts the burner mode to operate for 2-3 minutes, switches to the low oxygen mode to operate for 1-2 minutes, then switches to the high oxygen mode until the molten steel temperature reaches 1550-1570°C, adopts the medium oxygen mode until the molten steel temperature reaches 1600°C, and then switches to the holding mode;

[0013] The oxygen supply modes of the furnace door oxygen lance include low oxygen mode and high oxygen mode; the furnace door oxygen lance adopts low oxygen mode 5-10 minutes before the start of smelting, until it is switched to high oxygen mode synchronously with the furnace wall oxygen lance, and after the molten steel temperature reaches 1600°C, the furnace door oxygen lance is closed and carbon powder is sprayed;

[0014] The slag making system is to use active lime and light-burned dolomite in a mass ratio of 1.5:1 to make slag, and add them in batches through a furnace top silo, with the addition amount of each batch being 300-600kg.

[0015] Furthermore, the steel retention system provides conditions for the initial melting of the next smelting furnace through the residual molten steel and highly oxidizing slag in the furnace, and the amount of retained steel is controlled to be 10% of the mass of the molten steel in the furnace after the smelting is completed.

[0016] Furthermore, the size of the raw scrap steel added to the electric arc furnace in step 1) does not exceed 1 m;

[0017] Calculated by weight percentage, the raw material molten iron has a C content of ≥4.0%, a Si content of ≤0.7%, a P content of ≤0.12%, and a S content of ≤0.005%.

[0018] Furthermore, in step 1), the speed of adding raw molten iron into the electric arc furnace is 8-12 t / min.

[0019] Furthermore, in the step 2), the current intensity of the electromagnetic stirring at the furnace bottom during the smelting process is 100-1000A, and the frequency of the electromagnetic stirring is 2-30Hz.

[0020] Furthermore, during the smelting process of step 2), the average movement speed of the molten steel in the electric arc furnace is not less than 0.5 m / s.

[0021] Furthermore, in step 3), the carbon-oxygen product of the molten steel at the end point of smelting is less than 0.0028.

[0022] Furthermore, in terms of weight percentage, the C content of the residual molten steel in the steel retention system is 0.05-0.20%, and the P content is ≤0.015%.

[0023] Furthermore, in terms of weight percentage, the T.Fe content in the highly oxidizing slag is 20-30%, and the MgO content is 8-10%.

[0024] It can be seen from the above technical solutions that the technical solutions of the present invention have the following beneficial effects:

[0025] The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking disclosed in the present invention comprises: 1) determining the steel retention amount in the electric arc furnace according to the steel retention system, adding the raw scrap steel into the electric arc furnace and adding the raw molten iron into the electric arc furnace through the rear chute after power on and melting, so that the carbon content of the raw materials in the electric arc furnace is controlled to be 1.6-2.5%; 2) smelting oxygen blowing according to the preset power supply system and oxygen supply system, adopting electromagnetic stirring at the bottom of the furnace during the smelting process, and the raw materials in the electric arc furnace undergo a melting period and an oxidation period in the smelting oxygen blowing process in sequence, and the temperature reaches the preset target Then slag is made according to the preset slag making system, and the basicity of the slag is controlled to be 2.0-2.5 during the slag making process; 3) the molten steel in the electric arc furnace is sampled and the temperature is measured and the oxygen is determined, the smelting end temperature is controlled to be 1590-1610°C, and EBT steel is tapped; the present invention can effectively reduce the carbon-oxygen product value of the molten steel by optimizing the steel retention system, power supply system, oxygen supply system, slag making system, and designing the carbon dosage and power stirring; under the condition of the same steel tapping carbon content, by reducing the oxygen content in the molten steel, the deoxidation alloy consumption is reduced, and the metal material recovery rate is improved.

[0026] Compared with the prior art, the present invention achieves the purpose of reducing the carbon-oxygen accumulation at the end point of electric arc furnace smelting by optimizing the thermodynamic and kinetic conditions in the smelting process; in the method, 10% of the mass of the previous furnace of molten steel is retained in the furnace to accelerate the slag formation of the next furnace of molten steel as soon as possible and speed up the smelting speed; the carbon content of the raw materials entering the furnace is 1.6-2.5%, the purpose of which is to ensure the basic conditions for maintaining foamy slag in the furnace; electromagnetic stirring is adopted at the bottom of the furnace during the smelting process to enhance the fluidity of the molten steel and ensure the temperature uniformity of the flow field; the power supply and oxygen supply system are optimized to speed up the smelting process and ensure the end point composition; the basicity of the slag is controlled at 2.0-2.5 during the slag making process to dephosphorize and control the viscosity of the molten steel; the end point temperature of smelting is controlled at 1590-1610°C because the carbon-oxygen accumulation tends to increase with increasing temperature, and low-temperature steelmaking is beneficial to reducing the carbon-oxygen accumulation. The control method for reducing carbon-oxygen product in electric arc furnace steelmaking disclosed in the present invention can reduce the carbon-oxygen product at the end point of electric arc furnace smelting to below 0.0028 on the basis of reducing the power consumption of the electric arc furnace and not increasing the cost of additional deoxidation alloy, and has significant economic benefits.

[0027] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

[0028] The foregoing and other aspects, embodiments and features of the present invention will be more fully understood from the following description. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or will be learned from the practice of the specific embodiments according to the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme of the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.

[0030] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular form of "a", "an" or "the" and other similar words do not indicate a quantitative limitation, but indicate the existence of at least one. "Include" or "comprises" and other similar words mean that the elements or objects appearing before "include" or "comprises" include the features, wholes, steps, operations, elements and / or components listed after "include" or "comprises", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0031] Based on the fact that the carbon-oxygen accumulation level of a conventional electric arc furnace is between 0.0032 and 0.0045, the method of reducing the carbon-oxygen accumulation value of the electric arc furnace proposed in the prior art can achieve the purpose, but the method cost is high, and the technical implementation is relatively immature, and there are safety hazards; therefore, the present invention aims to propose a control method for reducing the carbon-oxygen accumulation in electric arc furnace steelmaking, by controlling the carbon content of the raw materials entering the furnace, optimizing the power supply and oxygen supply system of the smelting process to achieve electrical and oxygen balance to achieve maximum smelting of foamed slag, and achieve the purpose of reducing the oxygen content in molten steel under the same carbon content conditions when tapping steel.

[0032] Specifically, the control method for reducing carbon-oxygen accumulation in electric arc furnace steelmaking disclosed in the present invention comprises the following steps:

[0033] 1) The amount of steel retained in the electric arc furnace is determined according to the steel retention system. The raw scrap steel added to the electric arc furnace is added to the raw molten iron into the electric arc furnace through the rear chute after power is turned on and melted, so that the carbon content of the raw materials in the electric arc furnace is controlled to 1.6-2.5%;

[0034] Since carbon is oxidized before iron, controlling the carbon content of the raw materials entering the furnace can reduce the burning of iron during oxygen blowing during the melting period, and can also reduce the melting point of scrap steel and accelerate the formation of the molten pool.

[0035] The formula for calculating the carbon content is: (amount of molten iron × carbon content of molten iron + amount of pig iron × carbon content of pig iron + amount of scrap steel × carbon content of scrap steel) / (amount of molten iron + amount of pig iron + amount of scrap steel). Therefore, if there is less molten iron in the raw material, the carbon content can be increased to the target range by adding pig iron.

[0036] Among them, the steel retention system is to provide conditions for the initial melting of the next smelting furnace through the residual molten steel and highly oxidizing slag in the furnace, and the amount of retained steel is controlled to be 10% of the mass of the molten steel in the furnace after the smelting is completed; in terms of weight percentage, the C content of the residual molten steel in the steel retention system is 0.05-0.20%, and the P content is ≤0.015%; in terms of weight percentage, the T.Fe content in the highly oxidizing slag is 20-30%, and the MgO content is 8-10%.

[0037] In addition, the size of the raw scrap steel added to the electric arc furnace does not exceed 1m; in terms of weight percentage, the C content of the raw molten iron is ≥4.0%, the Si content is ≤0.7%, the P content is ≤0.12%, and the S content is ≤0.005%. The speed of adding the raw molten iron to the electric arc furnace is 8-12t / min.

[0038] 2) Smelting oxygen blowing is carried out according to the preset power supply system and oxygen supply system. During the smelting process, electromagnetic stirring is adopted at the bottom of the furnace. The current intensity of the electromagnetic stirring at the bottom of the furnace is 100-1000A, and the electromagnetic stirring frequency is 2-30Hz, so that the average movement speed of the molten steel in the electric arc furnace is not less than 0.5m / s; the raw materials in the electric arc furnace undergo a melting period and an oxidation period in sequence during the smelting oxygen blowing process, and slag is made according to the preset slag making system after the temperature reaches the preset target, and the basicity of the slag is controlled to be 2.0-2.5 during the slag making process;

[0039] The power supply system is the selection of power supply gears for the electric arc furnace, including: the smelting arc starting gear is controlled at gear 8, the drilling process uses gears 10-13, the smelting stage uses gear 15, the melting stage uses gears 10-12 after melting, and the arc is exposed at the end of smelting, and the gear is adjusted downward to gears 4-5;

[0040] Specifically, in the power supply system, the voltage and current corresponding to each gear are shown in Table 1 below.

[0041] Table 1 Voltage and current corresponding to power supply gear

[0042]

[0043] The oxygen supply system is to set the oxygen supply mode of the furnace wall oxygen lance and the furnace door oxygen lance; the oxygen supply modes of the furnace wall oxygen lance include burner mode, low oxygen mode, medium oxygen mode, high oxygen mode and holding mode; at the beginning of smelting, the furnace wall oxygen lance adopts the burner mode for 2-3 minutes, switches to the low oxygen mode for 1-2 minutes, and then switches to the high oxygen mode until the molten steel temperature reaches 1550-1570°C, adopts the medium oxygen mode until the molten steel temperature reaches 1600°C, and then switches to the holding mode; the oxygen supply modes of the furnace door oxygen lance include low oxygen mode and high oxygen mode; the furnace door oxygen lance adopts the low oxygen mode 5-10 minutes before the start of smelting until it is switched to the high oxygen mode synchronously with the furnace wall oxygen lance, and after the molten steel temperature reaches 1600°C, the furnace door oxygen lance is closed and carbon powder is sprayed; specifically, the flow rates set for various modes of the furnace wall oxygen lance and the furnace door oxygen lance in the oxygen supply system are shown in Table 2 below.

[0044] The slag making system is to use active lime and light-burned dolomite in a mass ratio of 1.5:1 to make slag, and add them in batches through a furnace top silo, with the addition amount of each batch being 300-600kg.

[0045] Table 2 Various modes of oxygen lances on furnace wall and furnace door

[0046]

[0047] 3) After sampling the molten steel in the electric arc furnace, the temperature is measured and the oxygen is determined. The smelting end temperature is controlled at 1590-1610℃, and EBT tapping is carried out after the tapping conditions are met.

[0048] The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking disclosed in the present invention is further specifically introduced below in conjunction with specific embodiments.

[0049] Example 1

[0050] The amount of steel left in the electric arc furnace is 10t, the amount of scrap steel added as the main raw material is 56t, the amount of molten iron added is 62t, the molten iron ratio is 52.5%, and the calculated carbon content is 2.2%. After closing the furnace cover, the power is turned on at gear 8 for arc starting and gear 13 for drilling. The oxygen lance on the furnace wall is adjusted from the holding mode to the low fire mode; the molten iron is added from the chute behind the furnace. After 3 minutes of power-on, the oxygen lance on the furnace door is put into the low fire mode, and the oxygen lance on the furnace wall is adjusted to the medium fire mode. After 6 minutes of power-on, the oxygen lance on the furnace door and the oxygen lance on the furnace wall are adjusted to the high fire mode. At the same time, electromagnetic stirring is put into the furnace bottom. After 16 minutes of power-on, the first temperature measurement is 1570℃. After 20 minutes of power-on, the second temperature measurement is 1605℃. The power is turned off, the oxygen lance on the furnace wall is adjusted to the holding mode, the oxygen in the oxygen lance on the furnace door is turned off, carbon powder is sprayed, and the slag is thickened. The basicity of the slag is controlled to 2.5 during the slag making process; the total power consumption of the furnace is 18180Kwh, and the total oxygen supply is 280Nm 3 , natural gas consumption 269Nm 3 , lime consumption is 3083kg, light-burned dolomite consumption is 1905kg, steel output is 105t, the final C content of the furnace steel is measured to be 0.062%, the fixed oxygen value is 450ppm, and the calculated carbon-oxygen product is 0.0028.

[0051] Example 2

[0052] The steel retention in the electric arc furnace is 10t, the main raw material scrap steel addition amount is 54t, the molten iron addition amount is 66t, the molten iron ratio is 55.0%, and the calculated carbon content is 2.3%. After closing the furnace cover, the power supply is 8 gears for arc starting and 13 gears for drilling. The oxygen lance on the furnace wall is adjusted from the holding mode to the low fire mode. Molten iron is added from the chute behind the furnace. After 3 minutes of power-on, the oxygen lance on the furnace door is put into the low fire mode, and the oxygen lance on the furnace wall is adjusted to the medium fire mode. After 5 minutes of power-on, the oxygen lance on the furnace door and the oxygen lance on the furnace wall are adjusted to the high fire mode. At the same time, electromagnetic stirring is put into the furnace bottom. After 15 minutes of power-on, the first temperature measurement is 1550℃. After 21 minutes of power-on, the second temperature measurement is 1602℃. After power-off, the oxygen lance on the furnace wall is adjusted to the holding mode, the oxygen in the oxygen lance on the furnace door is turned off, carbon powder is sprayed, and the slag is thickened. The basicity of the slag is controlled to 2.0 during the slag making process. The total power consumption of the furnace is 17450Kwh, and the total oxygen supply is 2762Nm 3, natural gas consumption 223Nm 3 , lime consumption was 2818kg, light-burned dolomite consumption was 1650kg, the steel output was 108t, the final C content of the furnace steel was measured to be 0.04%, the fixed oxygen value was 650ppm, and the calculated carbon-oxygen product was 0.0026.

[0053] Example 3

[0054] The amount of steel left in the electric arc furnace is 10t, the amount of scrap steel added as the main raw material is 78t (including 10 tons of pig iron), the amount of molten iron added is 40t, the molten iron ratio is 33.9%, and the calculated carbon content is 1.8%. After closing the furnace cover, the power is supplied to 8 gears for arc starting and 13 gears for drilling. The oxygen lance on the furnace wall is adjusted from the holding mode to the low fire mode. Molten iron is added from the chute behind the furnace. After 4 minutes of power-on, the oxygen lance on the furnace door is put into the low fire mode, and the oxygen lance on the furnace wall is adjusted to the medium fire mode. After 8 minutes of power-on, the oxygen lance on the furnace door and the oxygen lance on the furnace wall are adjusted to the high fire mode. At the same time, electromagnetic stirring is put into the furnace bottom. After 18 minutes of power-on, the first temperature measurement is 1570℃. After 23 minutes of power-on, the second temperature measurement is 1600℃. After power-off, the oxygen lance on the furnace wall is adjusted to the holding mode, the oxygen lance on the furnace door is turned off, carbon powder is sprayed, and the slag is thickened. The basicity of the slag is controlled to 2.3 during the slag making process. The total power consumption of the furnace is 21300Kwh, and the total oxygen supply is 2547Nm 3 , natural gas consumption 260Nm 3 , lime consumption is 2980kg, light-burned dolomite consumption is 1985kg, steel output is 108t, the final C content of the furnace steel is measured to be 0.052%, the fixed oxygen value is 530ppm, and the calculated carbon-oxygen product is 0.00276.

[0055] The present invention discloses a control method for reducing carbon-oxygen accumulation in electric arc furnace steelmaking. By optimizing the steel retention system, carbon content, power supply system, oxygen supply system, slag making system and equipping with power stirring, the carbon-oxygen accumulation value is effectively reduced. Under the condition of the same steel tapping carbon content, the oxygen content in molten steel is reduced, the consumption of deoxidation alloy is reduced, and the metal material recovery rate is improved. Compared with the prior art, when the present invention is implemented, the carbon-oxygen accumulation at the end point of electric arc furnace smelting can be reduced to below 0.0028 on the basis of reducing the power consumption of the electric furnace and not increasing the cost of additional deoxidation alloy. The economic benefits are very significant and the safety hazards are low.

[0056] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking, characterized in that: The steps include: 1) The amount of steel retained in the electric arc furnace is determined according to the steel retention system. The raw scrap steel added to the electric arc furnace is added to the raw molten iron into the electric arc furnace through the rear chute after power is turned on and melted, so that the carbon content of the raw materials in the electric arc furnace is controlled to 1.6-2.5%; 2) Smelting oxygen blowing is carried out according to the preset power supply system and oxygen supply system. Electromagnetic stirring is adopted at the bottom of the furnace during the smelting process. The raw materials in the electric arc furnace undergo a melting period and an oxidation period in sequence during the smelting oxygen blowing process. After the temperature reaches the preset target, slag is made according to the preset slag making system. During the slag making process, the basicity of the steel slag is controlled to be 2.0-2.5; 3) After sampling the molten steel in the electric arc furnace, the temperature is measured and the oxygen is determined. The smelting end temperature is controlled at 1590-1610°C. After the tapping conditions are met, EBT tapping is performed; The power supply system is the selection of power supply gears for the electric arc furnace, including: the arc starting gear is controlled at gear 8 during smelting, gears 10-13 during drilling, gear 15 during smelting, gears 10-12 after melting, and the arc is exposed at the end of smelting, and the gear is adjusted downward to gears 4-5; The oxygen supply system is to set the oxygen supply mode of the furnace wall oxygen lance and the furnace door oxygen lance; The oxygen supply modes of the furnace wall oxygen lance include burner mode, low oxygen mode, medium oxygen mode, high oxygen mode and holding mode; at the beginning of smelting, the furnace wall oxygen lance adopts the burner mode to operate for 2-3 minutes, switches to the low oxygen mode to operate for 1-2 minutes, then switches to the high oxygen mode until the molten steel temperature reaches 1550-1570°C, adopts the medium oxygen mode until the molten steel temperature reaches 1600°C, and then switches to the holding mode; The oxygen supply modes of the furnace door oxygen lance include low oxygen mode and high oxygen mode; the furnace door oxygen lance adopts low oxygen mode 5-10 minutes before the start of smelting, until it is switched to high oxygen mode synchronously with the furnace wall oxygen lance, and after the molten steel temperature reaches 1600°C, the furnace door oxygen lance is closed and carbon powder is sprayed; The slag making system is to use active lime and light-burned dolomite in a mass ratio of 1.5:1 to make slag, and add them in batches through the furnace top bunker, with the addition amount of each batch being 300-600kg; The steel retention system is to provide conditions for the initial melting of the next smelting furnace through the residual molten steel and highly oxidizing slag in the furnace, and the amount of retained steel is controlled to be 10% of the mass of the molten steel in the furnace after the smelting is completed.

2. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1 is characterized in that: The size of the raw scrap steel added to the electric arc furnace in step 1) does not exceed 1 m; Calculated by weight percentage, the raw material molten iron has a C content of ≥4.0%, a Si content of ≤0.7%, a P content of ≤0.12%, and a S content of ≤0.005%.

3. The control method for reducing carbon-oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: In the step 1), the speed of adding raw molten iron into the electric arc furnace is 8-12 t / min.

4. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: In the step 2), during the smelting process, the current intensity of the electromagnetic stirring at the furnace bottom is 100-1000A, and the frequency of the electromagnetic stirring is 2-30Hz.

5. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: During the smelting process of step 2), the average movement speed of the molten steel in the electric arc furnace is not less than 0.5 m / s.

6. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: In the step 3), the carbon-oxygen product of the molten steel at the end point of smelting is less than 0.0028.

7. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: Calculated by weight percentage, the C content of the residual molten steel in the steel retention system is 0.05-0.20%, and the P content is ≤0.015%.

8. The control method for reducing carbon and oxygen accumulation in electric arc furnace steelmaking according to claim 1, characterized in that: In terms of weight percentage, the T.Fe content in the highly oxidizing slag is 20-30%, and the MgO content is 8-10%.

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