A method for accurately controlling the carbon content at the converter end point

Abstract

The present invention belongs to the field of metallurgy technology and specifically relates to a method for precisely controlling the carbon content at the end of a converter. In the late stage of converter smelting, when the CO content in the flue gas reaches a peak and then significantly decreases, the carbon content of molten steel at the flue gas CO peak under different slag amounts and oxygen supply intensities is determined by measurement. Based on practical data, a constant oxygen supply intensity control model for different decarburization amounts after the flue gas CO reaches a peak is developed under different slag amounts. In actual production, based on the required carbon content of the converter steel grade at the end of the converter smelting and the established constant oxygen supply intensity control model for different decarburization amounts under different slag amounts, the carbon content of the molten steel at the flue gas CO peak is measured to determine the oxygen supply intensity and the timing for stopping the oxygen supply after the flue gas CO peak. This method can achieve precise control of the converter's end-point carbon content, reduce the amount of carbon added to the molten steel during the steelmaking process, and improve alloy recovery, which is of great significance for enterprises in reducing carbon emissions and lowering production costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy, and in particular relates to a method for accurately controlling the carbon content at the end point of a converter. Background Art

[0002] Converter smelting removes carbon from molten iron by supplying oxygen into the furnace. At the end of smelting, due to improper control of parameters such as oxygen supply intensity and oxygen supply stop timing, the carbon content of the converter end point cannot be accurately controlled according to the requirements of the smelting steel grade. When the end point carbon content is higher than the steel grade requirement, secondary oxygen supply decarburization is required, and the smelting cycle is extended; when the end point carbon content is lower than the steel grade requirement, carbon increase is required by adding carbon increaser during the converter tapping process to meet the carbon content requirement of the smelting steel grade. Secondary oxygen supply and addition of carbon increaser lead to increased oxygen consumption and carbon increaser cost.

[0003] In addition, the secondary oxygen supply at the converter end and the low carbon content at the end both lead to an increase in the oxygen content in the molten steel, which has a significant impact on the improvement of product quality. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned problems and provides a method for precisely controlling the carbon content at the end of a converter. In the late stage of converter smelting, when the CO content in the flue gas reaches a peak and then significantly decreases, the carbon content of the molten steel at the peak of the flue gas CO under different slag amounts and oxygen supply intensities is determined by measurement. Based on practical data, a constant oxygen supply intensity control model for different decarburization amounts after the flue gas CO reaches a peak is developed under different slag amounts. In actual production, based on the required carbon content of the converter steel grade at the end of the converter smelting and the established constant oxygen supply intensity control model for different decarburization amounts under different slag amounts, the carbon content of the molten steel at the peak of the flue gas CO is measured to determine the oxygen supply intensity and the timing for stopping the oxygen supply after the flue gas CO peak. This method can achieve precise control of the carbon content at the end of the converter, reduce the amount of carbon added to the molten steel during the steelmaking process, and improve the alloy recovery rate, which is of great significance to enterprises in reducing carbon emissions and lowering production costs.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solution: A method for accurately controlling the carbon content at the end point of a converter comprises the following steps:

[0006] S1. In the late stage of converter smelting, when the CO content in the flue gas reaches the peak and the decline reaches the set amplitude, the carbon content of the molten steel at the CO peak in the flue gas is measured, and the corresponding values ​​of the carbon content of the molten steel at the CO peak in the flue gas under different slag amounts and oxygen supply intensities are determined, and a corresponding database is established; since the CO concentration curve is an undulating curve, it is impossible to accurately determine which period is the CO peak during the smelting process. Therefore, the period when the CO concentration in the late stage of converter smelting has a significant decline is used as the CO peak, and the CO peak is judged and confirmed by setting a decline amplitude threshold. The CO peak in the present invention refers to the period when the CO content reaches the peak and the decline amplitude reaches the set amplitude;

[0007] S2. Develop a constant oxygen supply intensity control model for different decarbonization amounts after CO in flue gas reaches its peak under different slag amounts;

[0008] Specifically, according to the decarburization amount that needs to be removed from the carbon content of the molten steel at the peak of CO in the flue gas to the end-point carbon content and the corresponding slag amount under different slag amounts and oxygen supply intensities, a constant oxygen supply intensity control model for different decarburization amounts under different slag amounts and conditions of different end-point carbon contents is formulated. The constant oxygen supply intensity control model includes a constant oxygen supply intensity and a constant oxygen supply time that correspond one-to-one to the slag amount, the carbon content of the molten steel at the peak of CO in the flue gas, and the end-point carbon content;

[0009] S3. When the CO content in the flue gas reaches the peak value and then decreases to the set value, the carbon content of the molten steel at the CO peak value in the flue gas is measured, and the slag amount is determined according to the database established in step S1 based on the corresponding oxygen supply intensity. Further, according to the endpoint carbon content corresponding to the smelting steel grade and the constant oxygen supply intensity control model established in step S2, the subsequent constant oxygen supply intensity and constant oxygen supply time, that is, the timing to stop the oxygen supply, are determined.

[0010] The technical solution of the present invention further comprises: in step S2, in the constant-time oxygen supply intensity control model, under the same slag amount and the same endpoint carbon content, the constant-time oxygen supply intensity corresponding to the molten steel carbon content at different CO peaks is the same, and the constant-time oxygen supply time corresponding to the molten steel carbon content at different CO peaks is proportional to the amount of decarburization required from the molten steel carbon content at the CO peak to the endpoint carbon content. In order to reduce the data volume of the constant-time oxygen supply intensity control model, under the same slag amount and the same endpoint carbon content, the constant-time oxygen supply intensity values ​​corresponding to the molten steel carbon content at different CO peaks are set to the same value, and the constant-time oxygen supply time corresponding to the molten steel carbon content at different CO peaks is proportional to the amount of decarburization required from the molten steel carbon content at the CO peak to the endpoint carbon content, that is, the decarburization efficiency corresponding to the same slag amount and the same endpoint carbon content is ensured to be the same.

[0011] The technical solution of the present invention also includes: in the step S1, the setting amplitude is specifically: a decrease of more than 5% within 10 seconds.

[0012] The technical solution of the present invention also includes: in the step S1, the calculation basis of the decrease range of the CO content in the flue gas after reaching the peak value is a CO concentration curve formed by measuring with a laser flue gas analyzer installed in the flue.

[0013] The present invention also provides a technical solution: in step S1, the late stage of converter smelting occurs after the converter oxygen supply time reaches 5 / 6 of the normal oxygen supply time. During the smelting process, the CO concentration curve may also experience a drop of more than 5% in 10 seconds. To prevent misjudgment of the peak value, the oxygen supply time period is used for auxiliary judgment to ensure the accuracy of peak value judgment. The normal oxygen supply time is a range. After the oxygen supply intensity is determined, it is mainly related to the slag amount, the carbon, silicon, manganese and other substances that need to be oxidized in the converter feedstock, the oxygen lance position, etc., but the overall fluctuation is not large. After the converter begins oxygen supply, the theoretical oxygen supply time can be calculated based on the above parameters. The current converter steelmaking automatic control operation model also has a theoretical value for the oxygen supply time.

[0014] The technical solution of the present invention also includes: in the step S1, the carbon content in the molten steel is determined by TSC using a secondary gun, specifically using a spectrometer for detection.

[0015] The technical solution of the present invention also has: in the step S1, the different slag amounts are the values ​​of slag per ton of steel in the furnace, and the slag amount values ​​are determined according to the slag amount left in the previous furnace, the amount of auxiliary materials added to the furnace, and the Si, Mn, and P contents in the metal material;

[0016] Slag amount = (slag amount left in the upper furnace + lime addition amount + dolomite addition amount + molten iron Si content * molten iron amount * (SiO2 molecular weight / Si molecular weight) + molten iron Mn content * molten iron amount * (MnO molecular weight / Mn molecular weight + molten iron P content * molten iron amount * (P2O5 molecular weight / 2P molecular weight)) / molten steel amount. Since the oxygen supply time in the smelting process is long and there are many process variables, the use of full-process parameters to calculate the slag amount and then adjust the oxygen supply intensity cannot meet the production rhythm needs, resulting in a large control deviation of the terminal carbon content. The present invention calculates the slag amount after the CO peak in the flue gas and controls the carbon content in the molten steel. At this time, the slag amount is stable, which can improve the control accuracy of the converter terminal carbon content. The slag amount calculated according to the slag amount left in the upper furnace, the amount of auxiliary materials added in this furnace and the Si, Mn and P contents in the metal material is close to the actual process slag amount. Since the slag amount corresponds to the decarburization speed, the subsequent oxygen supply intensity and oxygen supply time can be controlled based on the slag amount.

[0017] The inventive concept of this invention is that the decarburization reaction in converter smelting occurs at the interface between molten steel and slag. In oxygen converter smelting, the intense agitation of the airflow forms a gas-slag-metal emulsion with a sufficient contact surface, providing a sufficiently large reaction interface for the carbon-oxygen reaction. Production practice has shown that, regardless of top or bottom blowing, the decarburization rate is primarily determined by the oxygen supply intensity, and exhibits a "slower at the beginning and faster in the middle" trend.

[0018] During the entire decarburization process, the curve of the change in decarburization rate is in the shape of a "step". This model is a simplification of the decarburization process. The actual blowing process is very complex. For example, the influence of the amount of ore and lime added during the process, the interference of splashing, the position of the oxygen lance, the fluctuation of the oxygen flow rate and other factors will affect the actual smelting process. However, the change in decarburization rate is basically similar under different oxygen supply intensities. Since the change in CO concentration in the converter flue gas is proportional to the decarburization rate during the slag making process, when the CO concentration reaches its peak and then drops significantly, it means that the decarburization rate is also in a downward stage, indicating that the decarburization of the molten steel has entered the later stage. At this time, the variables in the smelting process are reduced (for example, ore and lime are generally no longer added, and the change in the amount of slag is small), and the decarburization rate slows down. At this time, using this method to accurately control the end-point carbon content will greatly improve the control accuracy of the converter end-point carbon content compared to the method of controlling the entire smelting process, and the converter end-point carbon content can be accurately controlled as required.

[0019] The slag volume refers to the process slag volume. The size of the slag volume has a great influence on the decarburization speed of the smelting process. When the slag volume is large, when other parameters are the same (other parameters such as oxygen supply intensity, oxygen lance position), the oxygen utilization rate is low and the decarburization speed is slow. When the slag volume is small, the oxygen utilization rate is high and the decarburization speed is fast. The above shows that when other parameters are the same, the carbon content of the molten steel in the molten pool is different under different slag volumes and the same oxygen supply time. Under the same oxygen supply intensity, when the slag volume is large, the CO peak is delayed, and the carbon content in the molten steel is low at the CO peak; when the slag volume is small, the CO peak is advanced, and the carbon content in the molten steel is high at the CO peak; the principle is: when the slag volume is large, the slag thickness in the converter is high, which affects the reaction between oxygen and carbon in the molten steel, slows the decarburization speed, delays the overall smelting stages, and prolongs the oxygen supply time. According to production experience, under the condition of constant oxygen supply intensity, when the CO concentration reaches its peak, the slag amount and the carbon content of the molten steel are in a one-to-one correspondence. In the middle and late stages of oxygen supply, the slag amount no longer changes, that is, the slag amount is unchanged or negligible when and after the CO concentration reaches its peak.

[0020] Therefore, the present invention takes the point where the CO concentration in the flue gas decreases significantly after reaching the peak as a reference point, and obtains the carbon content in the molten steel corresponding to the CO peak in the flue gas under different slag amounts and oxygen supply intensities by detecting the carbon content in the molten steel at this time. Then, the slag amount of the furnace is obtained based on the slag amount left in the furnace, the auxiliary materials such as lime added during the smelting process, and the Si, Mn, P and other element contents of the raw materials entering the converter. Then, for different terminal carbon contents, a constant oxygen supply intensity control model for different decarburization amounts after the CO in the flue gas reaches the peak under different slag amounts is established. According to the requirements of the terminal carbon content of the corresponding steel grade, the carbon content at the CO peak and the constant oxygen supply intensity and constant oxygen supply time corresponding to the slag amount, i.e., the time to stop the oxygen supply, are obtained.

[0021] Compared with the prior art, the present invention has the following beneficial effects: in the late stage of converter smelting, when the CO content in the flue gas reaches a peak and then shows a significant decrease, the present invention determines the carbon content of the molten steel at the CO peak in the flue gas under different slag amounts and oxygen supply intensities by measuring, and establishes a corresponding database; based on practical data, a constant-time oxygen supply intensity control model for different decarburization amounts after the CO in the flue gas reaches a peak is formulated. In actual production, the carbon content of the molten steel at the CO peak in the flue gas is measured, the corresponding slag amount when the CO in the flue gas reaches a peak is determined according to the database, and then, based on the required endpoint carbon content corresponding to the steel grade being smelted in the converter, the constant-time oxygen supply intensity and the constant-time oxygen supply time after the CO in the flue gas reaches a peak, i.e., the timing of stopping the oxygen supply, are determined according to the constant-time oxygen supply intensity control model for different decarburization amounts under different slag amounts, thereby achieving precise control of the converter's endpoint carbon content, reducing the carbon addition amount of the molten steel in the steelmaking process, improving the alloy recovery rate, and effectively controlling the smelting cycle, which is of great significance to enterprises in reducing carbon emissions and production costs.

[0022] In addition, this method can prevent the increase in oxygen content in molten steel caused by secondary oxygen supply at the end of the converter and low carbon at the end, which is of great significance to improving product quality. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the embodiments.

[0024] A method for accurately controlling the carbon content at the end point of a converter, comprising the following steps:

[0025] In the later stages of converter smelting, when the CO content in the flue gas reaches its peak and then decreases by a set amount (specifically, a decrease of at least 5% within 10 seconds), the calculation of the decrease in the CO content in the flue gas after reaching its peak is based on a CO concentration curve measured by a laser flue gas analyzer installed in the flue. Transistor-assisted smelting (TSC) is used to measure the carbon content of the molten steel at the peak CO content in the flue gas. This is done using a spectrometer to determine the corresponding values ​​of the carbon content in the molten steel at the peak CO content in the flue gas at different slag amounts and oxygen supply intensities. A corresponding database is established, as shown in Table 1. The data in Table 1 represents actual production test data, while the data in Table 1 represents TSC measurement data.

[0026] Table 1 Corresponding values ​​of carbon content in molten steel at CO peak in flue gas under different slag amounts and oxygen supply intensities

[0027]

[0028] S2. Develop a constant oxygen supply intensity control model for different decarbonization amounts after CO in flue gas reaches its peak under different slag conditions.

[0029] Specifically, according to the decarburization amount that needs to be removed from the carbon content of molten steel at the peak of CO in the flue gas to the endpoint carbon content and the corresponding slag amount under different slag amounts and oxygen supply intensities, a constant oxygen supply intensity control model for different decarburization amounts under different slag amounts and different slag amounts is formulated. The constant oxygen supply intensity control model includes a constant oxygen supply intensity and a constant oxygen supply time that correspond one-to-one to the slag amount, the carbon content of molten steel at the peak of CO in the flue gas, and the endpoint carbon content, as shown in Table 2.

[0030] In step S2, in the constant oxygen supply intensity control model, under the same slag amount and the same endpoint carbon content, the constant oxygen supply intensity corresponding to the molten steel carbon content at different CO peaks is the same, and the constant oxygen supply time corresponding to the molten steel carbon content at different CO peaks is proportional to the amount of decarburization required to be removed from the molten steel carbon content at the CO peak to the endpoint carbon content. Since the decarburization amount is proportional to the constant oxygen supply time, only the constant oxygen supply intensity is shown in Table 2.

[0031] Table 2 shows the data obtained after theoretical calculation and practical demonstration. The specific calculation steps are as follows: first calculate the oxygen demand based on the required decarburization amount, and then multiply it by the oxygen utilization coefficient and the slag influence coefficient. According to Table 1, under the same slag amount, the greater the oxygen supply intensity, the lower the carbon content in the molten steel when the CO concentration in the flue gas reaches the peak. Among them, the carbon content in the molten steel is proportional to the oxygen supply intensity. Therefore, the carbon content at the peak of the CO concentration in the flue gas to the end point carbon content requires less further removal. The subsequent constant oxygen supply intensity and oxygen supply time can be determined based on the decarburization amount and slag amount.

[0032] Table 2 Constant oxygen supply intensity control model for different decarbonization amounts at different endpoint carbon contents and different slag amounts

[0033]

[0034] S3. In subsequent production, when the CO content in the flue gas reaches the peak and then drops to a set level, the carbon content of the molten steel at the CO peak in the flue gas is measured, and the slag amount is determined according to the database established in step S1 based on the corresponding oxygen supply intensity. Further, according to the endpoint carbon content corresponding to the smelting steel grade and the constant oxygen supply intensity control model established in step S2, the subsequent constant oxygen supply intensity and constant oxygen supply time, that is, the timing to stop the oxygen supply, are determined.

[0035] Example 1

[0036] The method of the present application is used to control the final carbon content of a 150t converter.

[0037] 1) The furnace contains 120 tons of molten iron, with a silicon content of 0.38% and a manganese content of 0.29%. 35 tons of scrap steel (all rebar briquettes, with a manganese content of 1.2% and a silicon content of 0.20%) are used. The amount of lime added is 3600 kg, the amount of dolomite is 1500 kg, the amount of slag left in the furnace is 2.4 tons, and the oxygen supply intensity is 3.4 m 3 / t.min, when oxygen is supplied to 680s (oxygen supply time is generally around 780s), the CO content in the flue gas is 78.05%, and then it drops significantly to 72.18% at 690s. The carbon content is determined to be 0.50% by TSC through the auxiliary gun, and the corresponding slag amount is determined to be 65kg / t.

[0038] 2) The final carbon requirement of this steel grade is 0.150%. Based on different slag amounts and different decarburization amounts, the constant oxygen supply intensity control model adopts 2.67m 3 Oxygen is supplied at a constant oxygen supply intensity of / t.min.

[0039] 3) After the oxygen supply was constant for 72 seconds, the oxygen supply was stopped and the molten steel sample was taken for analysis. The carbon content of the molten steel was 0.150%. The steel was directly tapped without adding a recarburizer during the tapping process.

[0040] 4) The smelting cycle of this furnace is 28 minutes.

[0041] Comparative Example 1

[0042] The existing method is used to control the final carbon content of a 150t converter.

[0043] 1) The furnace contains 120 tons of molten iron, with a silicon content of 0.38% and a manganese content of 0.29%. 35 tons of scrap steel (all rebar briquettes, with a manganese content of 1.2% and a silicon content of 0.20%) are used. The amount of lime added is 3600 kg, the amount of dolomite is 1500 kg, the amount of slag left in the furnace is 2.4 tons, and the oxygen supply intensity is 3.4 m 3 / t.min, when oxygen is supplied to 680s (oxygen supply time is generally around 780s), the CO content in the flue gas is 77.98%, and then it drops significantly to 72.0% at 690s. The carbon content determined by TSC through the auxiliary gun is 0.50%.

[0044] 2) The final carbon requirement of this furnace steel grade is 0.15%, and 3.4m 3 / t.min to supply oxygen.

[0045] 3) After 60 seconds of oxygen supply, the oxygen supply was stopped and the molten steel sample was taken for analysis. The carbon content of the molten steel was 0.101%. The steel was directly tapped and 95 kgt of recarburizer was added during the tapping process.

[0046] 4) The smelting cycle of this furnace is 28 minutes.

[0047] Comparative Example 2

[0048] The existing method is used to control the final carbon content of a 150t converter.

[0049] 1) The furnace contains 120 tons of molten iron, with a silicon content of 0.39% and a manganese content of 0.29%. 35 tons of scrap steel (all rebar briquettes, with a manganese content of 1.2% and a silicon content of 0.20%) are used. The amount of lime added is 3700 kg, the amount of dolomite added is 1500 kg, the amount of slag left in the furnace is 2.4 tons, and the oxygen supply intensity is 3.4 m 3 / t.min, when oxygen is supplied to 680s (oxygen supply time is generally around 780s), the CO content in the flue gas is 77.98%, and then it drops significantly to 72.0% at 690s. The carbon content determined by TSC through the auxiliary gun is 0.50%.

[0050] 2) The final carbon requirement of this steel grade is 0.15%, using 2.4m 3 / t.min to supply oxygen.

[0051] 3) After supplying oxygen for 75 seconds, the oxygen supply was stopped and the molten steel sample was taken for analysis. The carbon content of the molten steel was 0.182%, which was too high to meet the tapping requirements. The oxygen supply was continued for 15 seconds, and the carbon content of the sample was 0.151%. The steel was directly tapped without adding a recarburizer during the tapping process.

[0052] 4) The smelting cycle of this furnace is 32 minutes.

[0053] The casting amount, alloy addition amount and oxygen consumption of the embodiment and the comparative example are compared, and the results are shown in Table 3.

[0054] Table 3 Comparison of converter endpoint carbon control, carburizer addition and smelting cycle

[0055] Case End point carbon, % Carburizer addition amount, kg Smelting cycle, min Example 1 0.150 0 28 Comparative Example 1 0.101 95 28 Comparative Example 2 0.151 0 32 Comparison of implementation case 1 -0.049 +95 0 Comparison of implementation case 2 +0.001 0 +4

[0056] In summary, by comparing Example 1 with Comparative Examples 1 and 2, it can be seen that the method of the present application can accurately control the endpoint carbon content without adding a recarburizer, while effectively controlling the smelting cycle. The prior art only controls the oxygen supply intensity and oxygen supply time based on production experience. Although the oxygen supply intensity is fine-tuned, it is impossible to achieve quantitative and accurate control of the oxygen supply stop time for the endpoint carbon content, resulting in an excessively long smelting cycle or increased consumption of recarburizer.

Claims

1. A method for accurately controlling the carbon content at the converter endpoint, characterized in that: The following steps are involved: S1. In the late stage of converter smelting, when the CO content in the flue gas reaches the peak and then drops to the set range, the carbon content of the molten steel at the peak of CO in the flue gas is measured, and the corresponding values ​​of the carbon content of the molten steel at the peak of CO in the flue gas under different slag amounts and oxygen supply intensities are determined, and a corresponding database is established; The amount of slag when the CO concentration reaches the peak is the same as the amount of slag after the CO concentration reaches the peak, or the change in the slag amount is negligible; S2. Develop a constant oxygen supply intensity control model for different decarbonization amounts after CO in flue gas reaches its peak under different slag amounts; Specifically, according to the decarburization amount that needs to be removed from the carbon content of the molten steel at the peak of CO in the flue gas to the endpoint carbon content and the corresponding slag amount under different slag amounts and oxygen supply intensities, a constant oxygen supply intensity control model for different decarburization amounts under different endpoint carbon contents and different slag amounts is formulated. The constant oxygen supply intensity control model includes a constant oxygen supply intensity and a constant oxygen supply time corresponding to the slag amount, the carbon content of the molten steel at the peak of CO in the flue gas, and the endpoint carbon content; S3. When the CO content in the flue gas reaches the peak and then drops to the set range, the carbon content of the molten steel at the peak of CO in the flue gas is measured, and the slag amount is determined according to the database established in step S1 based on the corresponding oxygen supply intensity. Further, according to the endpoint carbon content corresponding to the smelting steel grade and the constant oxygen supply intensity control model established in step S2, the subsequent constant oxygen supply intensity and constant oxygen supply time, that is, the timing to stop the oxygen supply, are determined.

2. The method for accurately controlling the carbon content at the converter endpoint according to claim 1, wherein: In step S2, under the same slag amount and the same endpoint carbon content in the constant oxygen supply intensity control model, the constant oxygen supply intensity corresponding to the carbon content of the molten steel at different CO peak values ​​is the same, and the constant oxygen supply time corresponding to the carbon content of the molten steel at different CO peak values ​​is proportional to the amount of decarburization that needs to be removed from the carbon content of the molten steel at the CO peak value to the endpoint carbon content.

3. The method for accurately controlling the carbon content at the converter endpoint according to claim 1, wherein: In step S1, the setting range is specifically: a decrease of more than 5% within 10 seconds.

4. The method for accurately controlling the carbon content at the converter endpoint according to claim 3, wherein: In step S1, the calculation basis for the decrease in the CO content in the flue gas after reaching the peak value is a CO concentration curve formed by measuring with a laser flue gas analyzer installed in the flue.

5. The method for accurately controlling the carbon content at the converter endpoint according to claim 1, wherein: In step S1, the late stage of converter smelting is when the converter oxygen supply time reaches 5 / 6 of the normal oxygen supply time.

6. The method for accurately controlling the carbon content at the converter endpoint according to claim 1, characterized in that: In the step S1, the carbon content in the molten steel is determined by TSC using a secondary gun, specifically using a spectrometer for detection.

7. The method for accurately controlling the carbon content at the converter endpoint according to claim 1, wherein: In step S1, the different slag amounts are the values ​​of slag per ton of steel in the furnace, and the slag amount values ​​are determined according to the slag amount left in the previous furnace, the amount of auxiliary materials added to the furnace, and the Si, Mn, and P contents in the metal material; Slag amount = (slag amount left in the upper furnace + lime added amount + dolomite added amount + molten iron Si content * molten iron amount * (SiO2 molecular weight / Si molecular weight) + molten iron Mn content * molten iron amount * (MnO molecular weight / Mn molecular weight) + molten iron P content * molten iron amount * (P2O5 molecular weight / (2*P molecular weight))) / molten steel amount.

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