A method for reducing the tfe content of converter final slag

Abstract

The application relates to a method for reducing the TFe content of converter final slag, which comprises the following steps: periodically fluctuating the surface of the slag in the converter during tapping, determining the foaming slag degree of the slag in the periodic surface fluctuation through image recognition technology and threshold segmentation, determining the TFe content of the slag by measuring the slag surface liquid level and correcting the measured value of the slag surface liquid level, adding new composite carbon-based deoxidizers to the slag surface for stirring according to the TFe content of the slag, and reducing the final slag TFe content of the slag. The periodic fluctuation of the slag layer is excited by tilting the furnace body, dynamic image recognition and ranging data are combined to determine the TFe content of the slag in real time, specific composite deoxidizers are added according to the TFe content of the slag, the nitrogen gas stirring intensity is adjusted, the reduction reaction and metal drop aggregation are promoted, and the final slag iron oxide content is significantly reduced, the cleanliness of the molten steel is improved, and the production efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of converter steelmaking technology, and in particular to a method for reducing the TFe content in converter final slag. Background Technology

[0002] In converter steelmaking, the TFe content in the final slag is a key indicator affecting steel cleanliness, converter refractory life, and metal yield. Effectively controlling the TFe content in the final slag is of great significance for improving product quality and economic benefits. Currently, the industry generally adopts high-carbon tapping combined with carbon powder deoxidation to reduce the TFe content in the final slag. However, this method has significant limitations: the high-carbon tapping process restricts its application in the smelting of ultra-low carbon steels, and the reaction rate of carbon powder as a deoxidizer fluctuates greatly and its effect is unstable, resulting in insufficient precision in TFe content control, which affects steel quality and production costs.

[0003] Furthermore, existing technologies lack precise methods for determining the TFe content in slag, relying heavily on manual experience or simple testing, making it difficult to achieve rational addition of deoxidizers and process optimization. Traditional carbon-based deoxidizers have low density, easily float on the slag surface, resulting in low actual absorption rates. Moreover, traditional carbon-based deoxidizers are ineffective in promoting the effective agglomeration of molten metal droplets in the slag, limiting deoxidation efficiency. Simultaneously, the stirring process is relatively crude, and the nitrogen flow rate is not dynamically adjusted in conjunction with slag conditions, further restricting the deoxidation effect. These shortcomings collectively result in existing methods having limited overall improvement in steel cleanliness and metal recovery while reducing TFe content, failing to meet the higher requirements of steel production for quality and cost control. Summary of the Invention

[0004] This application provides a method for reducing the TFe content in converter final slag to solve the following technical problem: how to accurately determine the TFe content in converter final slag. This application provides a method for reducing the TFe content in converter final slag, including: During tapping, the slag in the converter experiences periodic surface fluctuations. The degree of foaming in the slag during these periodic surface fluctuations is determined using image recognition technology and threshold segmentation. The TFe content of the slag is determined by measuring the liquid level height of the slag surface and correcting the measured value of the liquid level. Based on the TFe content of the slag, a novel composite carbon-based deoxidizer is added to the slag surface and stirred to reduce the final TFe content of the slag.

[0005] Optionally, the swing angle of the converter during tapping is 30°~45°.

[0006] Optionally, the image recognition technology is used to analyze the degree of foaming in converter slag.

[0007] Optionally, the threshold segmentation method is used to analyze the threshold range of bubble rupture characteristics on the slag surface.

[0008] Optionally, the correction includes slag quantity correction and molten steel level correction; The method for correcting the slag volume is as follows: based on the total slag volume in the converter, the measured slag volume liquid level height is increased by 10mm to 15mm for every additional 1 ton of slag volume. The method for correcting the molten steel level is as follows: based on the total amount of molten steel in the converter, the measured slag surface level height is increased by 4mm to 8mm for every additional 1 ton of molten iron or scrap steel.

[0009] Optionally, the TFe content is determined based on the degree of foaming and the corrected liquid level height of the slag surface, including: When the number of bubbles breaking on the slag surface is ≥100 and the corrected slag surface liquid level height increases by ≥50cm compared to the baseline value, the TFe content is determined to be ≥20%. When the number of bubbles breaking on the slag surface is 80 to 100, and the corrected increase in the slag surface liquid level is 30 cm to 50 cm, the TFe content is determined to be 17% to 20%. When the number of bubble breakages on the slag surface is ≤80 and the corrected increase in the slag surface liquid level is ≤30cm, the TFe content is determined to be 10%~17%.

[0010] Optionally, the novel composite carbon-based deoxidizer has a composite particle structure, wherein the novel composite carbon-based deoxidizer uses pre-melted slag as a matrix, and carbon powder and limestone particles are embedded in the pre-melted slag matrix as dispersed phases; wherein the carbon powder is enriched on the surface of the composite particles.

[0011] Optionally, the ratio of the mass of the pre-melted slag, the mass of the carbon powder, and the mass of the limestone is (1.5~2.5):1:(1.5~2.5).

[0012] Optionally, the composition of the pre-melted slag, by mass fraction, is: barium oxide: 8%~12%, calcium oxide: 35%~45%, aluminum oxide: 30%~40%, calcium fluoride: 8%~12%, with the balance being unavoidable impurities.

[0013] Optionally, the amount of the novel composite carbon-based deoxidizer added is ≤300 parts.

[0014] Optionally, the particle size of the novel composite carbon-based deoxidizer is 10 mm to 30 mm.

[0015] Optionally, the stirring is performed using an oxygen lance to blow nitrogen gas; wherein the flow rate of the nitrogen gas is 2800 m³ / h. 3 / h~5000m 3 / h.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for reducing the TFe content in the final slag of a converter. The method includes: inducing periodic surface fluctuations in the slag within the converter during tapping; determining the degree of foaming in the slag during periodic surface fluctuations using image recognition technology and threshold segmentation; determining the TFe content in the slag by measuring the slag surface liquid level height and correcting the measured value; and adding a novel composite carbon-based deoxidizer to the slag surface and stirring according to the TFe content to reduce the final TFe content in the slag. First, the converter is shaken to expose the slag surface. Image recognition technology analyzes the bursting characteristics and number of bubbles on the slag surface to obtain visual characteristic parameters (degree of foaming) reflecting slag viscosity and surface tension. Second, distance measurement technology measures the slag layer thickness to obtain geometric characteristic parameters reflecting the volume of slag foaming. However, single parameters are susceptible to interference. Therefore, the solution introduces a crucial correction mechanism: compensating for the measured value through slag quantity and molten steel level. This eliminates the impact of fluctuations in the charge quantity on the test results, thus integrating visual and geometric features into a reliable comprehensive indicator of TFe content to measure the slag's oxidizability. This accurate judgment is the foundation for subsequent fine-grained control. Based on this diagnostic result, the system can make precise decisions and execute actions: quantitatively adding a highly efficient novel composite deoxidizer according to the TFe content and dynamically adjusting the nitrogen stirring intensity. This ensures that the deoxidation reaction is both sufficient and not excessive, ultimately efficiently reducing and separating iron oxides in the slag through the synergistic effect of chemical reduction and physical stirring, thereby stably reducing the final slag TFe content.

[0017] In summary, this solution solves the core "perception" problem in process control by transforming fuzzy "experience-based judgment" into "quantitative diagnosis" based on multi-source information fusion, thereby realizing the transformation from "extensive control" to "precise control". Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0020] Figure 1This is a flowchart illustrating a method for reducing the TFe content in converter final slag, as provided in an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges between 1 and 6 (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6). Unless otherwise specified, the terms "including" and "contains" used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship. "And / or" indicates that multiple situations can exist individually or simultaneously. Expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0023] Figure 1 This is a flowchart illustrating a method for reducing the TFe content in converter final slag, as provided in an embodiment of this application.

[0024] Please see Figure 1 This application provides a method for reducing the TFe content in converter final slag, comprising: S1. During tapping, the slag in the converter undergoes periodic surface fluctuations. The degree of foaming in the slag undergoing periodic surface fluctuations is determined by image recognition technology and threshold segmentation. S2. By measuring the liquid level height of the slag surface and correcting the measured value of the liquid level, the TFe content of the slag is determined. S3. Based on the TFe content of the slag, a novel composite carbon-based deoxidizer is added to the slag surface and stirred to reduce the final TFe content of the slag.

[0025] Image recognition technology: By capturing the spatiotemporal distribution characteristics of bubble bursts on the slag surface during converter tilting, a dynamic correlation model is established between the spatiotemporal distribution characteristics of bubble bursts and TFe content, thereby analyzing the slag oxidation state in real time and outputting process control signals. Threshold segmentation method: Based on a preset TFe content correlation model, the dynamically captured bubble characteristic parameters are delineated, and a quantitative grading signal of the slag oxidation state is output in real time to drive subsequent process control. Foamy slag degree: By quantifying the macroscopic state of bubble clusters in the slag, a dynamic index is dynamically characterized in real time as to the extent to which this macroscopic state hinders the TFe reduction reaction. This dynamic index constitutes a direct operational basis for deoxidizer addition and stirring intensity control.

[0026] In the above technical solution, a closed-loop control system of "perception-decision-execution" is constructed to address the problem of insufficient precision and reliance on experience in controlling the TFe content in the final slag of converters. First, by shaking the furnace and using image recognition technology to analyze the bubble characteristics on the slag surface, visual parameters of the slag viscosity and oxidizing properties are obtained. Simultaneously, a rangefinder is used to measure the slag layer thickness and correct for interference from slag quantity and molten steel level, obtaining reliable physical parameters. By integrating these two complementary types of information—visual and geometric—accurate online diagnosis of TFe content is achieved. Then, based on the diagnostic results, a novel composite deoxidizer with a specific structure is precisely added, and the nitrogen stirring intensity is dynamically adjusted to optimize the reduction reaction kinetics, promoting the polymerization and separation of metal droplets, thereby stably and efficiently reducing the TFe content in the final slag.

[0027] In some embodiments, the oscillation angle of the converter during tapping is 30° to 45°.

[0028] During tapping, the converter is rocked at an angle between 30° and 45°. This serves to fully expose the slag surface to ensure a clear field of view for image recognition. Simultaneously, moderate disturbance can stimulate bubble activity and highlight the differences in the state of slag layers with varying oxidizing properties, thereby improving judgment sensitivity. For example, the angle of the converter rocking can be 30°, 35°, 40°, 45°, etc.

[0029] In some implementations, the image recognition technology is used to analyze the degree of foaming in converter slag.

[0030] The core function of image recognition technology is to transform the visual state of foam residue into quantifiable objective indicators, replacing traditional human experience-based judgments and providing a reliable visual data foundation for achieving precise control.

[0031] In some implementations, the threshold segmentation method is used to analyze the threshold range of bubble rupture characteristics on the slag surface.

[0032] The role of threshold segmentation is to transform complex image information into clear discrimination criteria. By setting feature threshold intervals, it can accurately distinguish different foaming states, providing specific and actionable quantitative analysis basis for image recognition.

[0033] In some embodiments, the correction includes slag quantity correction and molten steel level correction; The method for correcting the slag volume is as follows: based on the total slag volume in the converter, the measured slag volume liquid level height is increased by 10mm to 15mm for every additional 1 ton of slag volume. The method for correcting the molten steel level is as follows: based on the total amount of molten steel in the converter, the measured slag surface level height is increased by 4mm to 8mm for every additional 1 ton of molten iron or scrap steel.

[0034] The purpose of slag quantity correction is to eliminate the interference caused by the different total slag quantities in the furnace on the measured slag level, ensuring that the measured slag level accurately reflects the height of the foamy slag. The purpose of molten steel level correction is to eliminate the lifting effect of molten steel volume on the slag layer, avoiding falsely high slag layer measurements due to changes in molten steel level, thereby accurately assessing the true thickness of the foamy slag. For example, based on the total slag quantity in the converter, for every additional ton of slag, the measured slag level height can be increased by 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.; based on the total molten steel quantity in the converter, for every additional ton of molten iron or scrap steel, the measured slag level height can be increased by 4mm, 5mm, 6mm, 7mm, 8mm, etc.

[0035] In some embodiments, the TFe content is determined based on the degree of foaming and the corrected liquid level height of the slag surface, including: When the number of bubbles breaking on the slag surface is ≥100 and the corrected slag surface liquid level height increases by ≥50cm compared to the baseline value, the TFe content is determined to be ≥20%. When the number of bubbles breaking on the slag surface is 80 to 100, and the corrected increase in the slag surface liquid level is 30 cm to 50 cm, the TFe content is determined to be 17% to 20%. When the number of bubble breakages on the slag surface is ≤80 and the corrected increase in the slag surface liquid level is ≤30cm, the TFe content is determined to be 10%~17%.

[0036] By establishing a correlation between the number of bubble bursts on the slag surface and the corrected slag surface liquid level, a precise TFe content determination criterion was constructed. This multi-parameter fusion determination model enables quantitative diagnosis of slag conditions, providing a reliable basis for subsequent precise control of TFe content. For example, when the number of bubble bursts on the slag surface is ≥100 and the corrected slag surface liquid level increases by ≥50cm compared to the baseline value, the TFe content can be determined to be 20%, 22%, 24%, 26%, etc.; when the number of bubble bursts on the slag surface is 80~100 and the corrected slag surface liquid level increases by 30cm~50cm, the TFe content can be determined to be 17%, 18%, 19%, 20%, etc.; when the number of bubble bursts on the slag surface is ≤80 and the corrected slag surface liquid level increases by ≤30cm, the TFe content can be determined to be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, etc.

[0037] In some embodiments, the novel composite carbon-based deoxidizer has a composite particle structure, wherein the novel composite carbon-based deoxidizer uses pre-melted slag as a matrix, and carbon powder and limestone particles are embedded in the pre-melted slag matrix as dispersed phases; wherein the carbon powder is enriched on the surface of the composite particles.

[0038] Pre-melted slag effectively overcomes the limitations of single-element carbon powder deoxidation through its unique physicochemical properties. Firstly, the density of pre-melted slag is higher than that of carbon powder, allowing it to sink deep into the slag layer for deep deoxidation, avoiding the problem of carbon powder floating on the slag surface and having low absorption rate due to its low density. Secondly, the limestone particles in the pre-melted slag undergo endothermic decomposition at high temperatures, generating CO2 bubbles that not only micro-stir the slag-metal mixture but also promote the reduction reaction of carbon and oxygen, thus significantly improving deoxidation efficiency. Furthermore, the composite particle structure, by enriching carbon powder on the surface of the pre-melted slag matrix, enables rapid activation and efficient reaction of the deoxidizer. Simultaneously, the gas stirring effect generated by the decomposition of embedded limestone effectively improves deoxidation efficiency and promotes the aggregation and separation of molten metal droplets.

[0039] In some embodiments, the ratio of the mass of the pre-melted slag, the mass of the carbon powder, and the mass of the limestone is (1.5~2.5):1:(1.5~2.5).

[0040] The mass ratio of pre-melted slag, carbon powder, and limestone is (1.5~2.5):1:(1.5~2.5). This ensures that the pre-melted slag matrix has a sufficient quantity to rapidly melt and form an active slag phase. Simultaneously, it provides a balanced ratio for the carbon powder and limestone, allowing the reducing effect of the carbon powder and the stirring effect of the gas generated by the decomposition of limestone to work synergistically and efficiently. This significantly improves reaction efficiency and the polymerization and separation effect of the metal phase while maintaining the deoxidation rate. For example, the mass ratio of pre-melted slag, carbon powder, and limestone can be 1.5:1:1.5, 2:1:2, 2.5:1:2.5, etc.

[0041] In some embodiments, the pre-melted slag, by mass fraction, comprises: barium oxide: 8%~12%, calcium oxide: 35%~45%, aluminum oxide: 30%~40%, calcium fluoride: 8%~12%, with the balance being unavoidable impurities.

[0042] The positive effects of limiting the mass fraction of barium oxide to 8%~12% include: barium oxide can effectively lower the melting point and viscosity of the pre-melted slag, promote the rapid melting and diffusion of the deoxidizer in the slag, and create favorable thermodynamic conditions for the reduction reaction. For example, the mass fraction of barium oxide can be 8%, 9%, 10%, 11%, 12%, etc.

[0043] The positive effects of limiting the mass fraction of calcium oxide to 35%~45% include: calcium oxide ensures that the pre-melted slag has sufficient alkalinity, which can effectively adsorb deoxidation products and stabilize slag properties, providing the necessary chemical environment for the deoxidation reaction. For example, the mass fraction of calcium oxide can be 35%, 37%, 39%, 41%, 43%, 45%, etc.

[0044] The positive effects of limiting the mass fraction of aluminum oxide to 30%~40% include: rationally adjusting the physical properties of the slag, such as viscosity and degree of foaming, maintaining good reactivity and covering ability, and optimizing reaction kinetics. For example, the mass fraction of aluminum oxide can be 30%, 32%, 34%, 36%, 38%, 40%, etc.

[0045] The positive effects of limiting the mass fraction of calcium fluoride to 8%~12% include: Calcium fluoride acts as a powerful flux, significantly lowering the slag melting point and improving slag fluidity, thereby accelerating the mass transfer process and comprehensively enhancing the rate and efficiency of the deoxidation reaction. For example, the mass fraction of calcium fluoride can be 8%, 9%, 10%, 11%, 12%, etc.

[0046] In some embodiments, the amount of the novel composite carbon-based deoxidizer added is ≤300 parts.

[0047] The addition amount of the novel composite carbon-based deoxidizer is ≤300 parts. While ensuring sufficient deoxidation effect, it effectively controls raw material costs and avoids negative impacts on steel cleanliness or temperature due to excessive addition, achieving a balance between economy and effectiveness. For example, the addition amount of the novel composite carbon-based deoxidizer can be 200 parts, 220 parts, 240 parts, 260 parts, 280 parts, 300 parts, etc.

[0048] In some embodiments, the particle size of the novel composite carbon-based deoxidizer is 10 mm to 30 mm.

[0049] The novel composite carbon-based deoxidizer has a particle size between 10mm and 30mm, ensuring that it has a suitable specific gravity and settling velocity. This prevents the deoxidizer from floating on the slag surface while providing sufficient reaction surface area, thereby optimizing the distribution and reaction kinetics of the deoxidizer in the slag and guaranteeing its effectiveness. For example, the particle size of the novel composite carbon-based deoxidizer can be 10mm, 15mm, 20mm, 25mm, 30mm, etc.

[0050] In some embodiments, the stirring is performed using an oxygen lance to purge nitrogen gas; wherein the flow rate of the nitrogen gas is 2800 m³ / h. 3 / h~5000m 3 / h.

[0051] High-intensity, deep-penetrating agitation is achieved using an oxygen lance. The oxygen lance propels nitrogen gas into the depths of the molten pool in a high-speed jet, resulting in intense agitation of the steel-slag interface, which is more conducive to promoting the polymerization of deoxidation products and mass transfer reactions. The nitrogen flow rate is 2800 m³ / s. 3 / h~5000m 3 The aim is to provide a stirring intensity between [amount] and [amount] per hour to ensure sufficient stirring to open the steel-slag interface and promote the reaction, while avoiding the risks of splashing, slag entrapment, and furnace lining erosion caused by over-stirring, thus achieving a balance between efficiency and safety. For example, the nitrogen flow rate can be 2800 m³ / h. 3 / h, 3800m 3 / h, 4800m 3 / h etc.

[0052] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards / industry standards / the disclosure herein; if there are no corresponding national standards / industry standards / the disclosure herein, they are performed according to generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer.

[0053] Example 1 In the practice of smelting low carbon steel in a converter (target carbon content of 0.07%~0.09%), the converter was shaken at an angle of 33° during tapping. By analyzing the degree of foaming through image recognition technology, it was found that the number of bubbles on the slag surface that broke was 30. Combined with the distance measuring instrument, the difference in slag surface liquid level height was 20cm, and it was initially judged that the TFe content was too low. Based on the preliminary assessment of the TFe content, 120 parts of a novel composite carbon-based deoxidizer (particle size 27mm, with a mass ratio of pre-melted slag, carbon powder, and limestone of 2:1:2) were added to the slag surface, and sprayed at a depth of 3000m. 3 Stirring with nitrogen at a flow rate of / h for 2 minutes to reduce the TFe content in the final residue.

[0054] Example 2 In the practice of smelting low carbon steel in a converter (target carbon content of 0.03%~0.05%), the converter was shaken at an angle of 35° during tapping. By analyzing the degree of foaming through image recognition technology, it was found that the number of bubbles on the slag surface that broke was 50. Combined with the distance measuring instrument measuring the difference in slag surface liquid level height of 50cm, it was initially judged that the TFe content was too high. Based on the preliminary assessment of the TFe content, 250 parts of a novel composite carbon-based deoxidizer (particle size 27mm, with a mass ratio of pre-melted slag, carbon powder, and limestone of 2:1:2) were added to the slag surface, and sprayed at a rate of 4000m... 3 Stirring with nitrogen at a flow rate of / h for 2 minutes to reduce the TFe content in the final residue.

[0055] Example 3 In the practice of smelting high carbon steel in a converter (target carbon content of 0.20%~0.25%), the converter was shaken at an angle of 35° during tapping. By analyzing the degree of foaming through image recognition technology, it was found that the number of bubbles on the slag surface was 30. Combined with the distance measuring instrument, the difference in slag surface liquid level height was 20cm, and it was initially judged that the TFe content was too low. Based on the preliminary assessment of TFe content, 220 parts of a novel composite carbon-based deoxidizer (particle size 27mm, with a mass ratio of pre-melted slag, carbon powder, and limestone of 2:1:2) were added to the slag surface, and sprayed at a depth of 3000m. 3 Stirring with nitrogen at a flow rate of / h for 2 minutes to reduce the TFe content in the final residue.

[0056] Example 4 In the practice of smelting high carbon steel in a converter (target carbon content of 0.30%~0.40%), the converter was shaken at an angle of 35° during tapping. By analyzing the degree of foaming through image recognition technology, it was found that the number of bubbles on the slag surface was 90. Combined with the distance measuring instrument, the difference in slag surface liquid level height was 40cm, and it was initially judged that the TFe content was too high. Based on the preliminary assessment of the TFe content, 280 parts of a novel composite carbon-based deoxidizer (particle size 27mm, with a mass ratio of pre-melted slag, carbon powder, and limestone of 2:1:2) were added to the slag surface, and sprayed at a rate of 4000m... 3 Stirring with nitrogen at a flow rate of / h for 2 minutes to reduce the TFe content in the final residue.

[0057] Example 5 In the practice of smelting high carbon steel in a converter (target carbon content of 0.25%~0.30%), the converter was shaken at an angle of 30° during tapping. By analyzing the degree of foaming through image recognition technology, it was found that the number of bubbles on the slag surface that broke was 90. Combined with the distance measuring instrument, the difference in the liquid level height on the slag surface was 42cm, and it was initially judged that the TFe content was too high. Based on the preliminary assessment of the TFe content, 280 parts of a novel composite carbon-based deoxidizer (particle size 27mm, with a mass ratio of pre-melted slag, carbon powder, and limestone of 2:1:2) were added to the slag surface, and sprayed at a rate of 4000m... 3 Stirring with nitrogen at a flow rate of / h for 2 minutes to reduce the TFe content in the final residue.

[0058] Comparative Example 1 When the slag at the converter's final stage has high oxidizing properties, the flame is bright white and thick with red smoke, the slag solidifies slowly, and the surface is shiny. Manual control is needed to avoid soft blowing at a high lance position, and timely hard blowing with a lower lance to enhance stirring and consume iron oxide in the slag. For medium and high carbon steel, the final carbon content can be increased, and a modifier can be added during tapping to reduce oxidation.

[0059] Effect data: The effect data of Examples 1 to 5 and Comparative Example 1 are shown in Table 1.

[0060] Experimental methods for obtaining effect data: 1. Inclusion content in molten steel: Samples were taken using a molten steel sampler. The samples were cylindrical with a diameter of 30 mm and a height of 100 mm. After inlaying, grinding and mirror polishing, the number and size of inclusions were counted under a scanning electron microscope.

[0061] 2. Metal recovery improvement: (Metal tapped / Total metal fed into furnace) × 100% Table 1

[0062] The above effect data table provides a clear comparison of the differences between various embodiments and comparative examples. The following conclusions can be drawn: As can be seen from Examples 1-5, the method of this application, through the combination strategy of novel composite carbon-based deoxidizer and nitrogen stirring, improves the cleanliness of molten steel (reducing the content of inclusions in molten steel by 7% to 15%) and increases the metal yield (increasing the metal yield by 0.2% to 1.3%), which is of great significance to the production of steel enterprises.

[0063] As can be seen from Comparative Example 1, the method of this application embodiment is not adopted. Relying on manual experience to judge the slag condition leads to the lag in regulation, resulting in the loss of control over the oxidation of the final slag and the over-oxidation of the molten steel. The mismatch between deoxidation operation and stirring intensity leads to the ineffective removal of inclusions and no improvement in metal yield. Moreover, the uncontrollability of the hard blowing of the pressure gun exacerbates the process fluctuation and splash risk, making it impossible to achieve stable production of high-cleanliness steel.

[0064] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for reducing the TFe content in converter final slag, characterized in that, The method includes: During tapping, the slag in the converter experiences periodic surface fluctuations. The degree of foaming in the slag during these periodic surface fluctuations is determined using image recognition technology and threshold segmentation. The TFe content of the slag is determined by measuring the liquid level height of the slag surface and correcting the measured value of the liquid level. Based on the TFe content of the slag, a novel composite carbon-based deoxidizer is added to the slag surface and stirred to reduce the final TFe content of the slag.

2. The method according to claim 1, characterized in that, The swing angle of the converter during tapping is 30°~45°.

3. The method according to claim 1, characterized in that, The image recognition technology is used to analyze the degree of foaming in converter slag; and / or, The threshold segmentation method is used to analyze the threshold range of bubble rupture characteristics on the slag surface.

4. The method according to claim 1, characterized in that, The corrections include slag quantity correction and molten steel level correction; The method for correcting the slag volume is as follows: based on the total slag volume in the converter, the measured slag volume liquid level height is increased by 10mm to 15mm for every additional 1 ton of slag volume. The method for correcting the molten steel level is as follows: based on the total amount of molten steel in the converter, the measured slag surface level height is increased by 4mm to 8mm for every additional 1 ton of molten iron or scrap steel.

5. The method according to claim 1, characterized in that, The TFe content is determined based on the degree of foaming and the corrected liquid level height of the slag surface, including: When the number of bubbles breaking on the slag surface is ≥100 and the corrected slag surface liquid level height increases by ≥50cm compared to the baseline value, the TFe content is determined to be ≥20%. When the number of bubbles breaking on the slag surface is 80 to 100, and the corrected increase in the slag surface liquid level is 30 cm to 50 cm, the TFe content is determined to be 17% to 20%. When the number of bubble breakages on the slag surface is ≤80 and the corrected increase in the slag surface liquid level is ≤30cm, the TFe content is determined to be 10%~17%.

6. The method according to claim 1, characterized in that, The novel composite carbon-based deoxidizer has a composite particle structure. The novel composite carbon-based deoxidizer uses pre-melted slag as the matrix, and carbon powder and limestone particles as the dispersed phase embedded in the pre-melted slag matrix; wherein, the carbon powder is enriched on the surface of the composite particles.

7. The method according to claim 6, characterized in that, The ratio of the mass of the pre-melted slag, the mass of the carbon powder, and the mass of the limestone is (1.5~2.5):1:(1.5~2.5).

8. The method according to claim 6, characterized in that, The pre-melted slag, by mass fraction, consists of: barium oxide: 8%~12%, calcium oxide: 35%~45%, aluminum oxide: 30%~40%, calcium fluoride: 8%~12%, with the balance being unavoidable impurities.

9. The method according to claim 1, characterized in that, The amount of the novel composite carbon-based deoxidizer added is ≤300 parts; and / or, The particle size of the novel composite carbon-based deoxidizer is 10mm~30mm.

10. The method according to claim 1, characterized in that, The stirring is carried out using an oxygen lance to blow nitrogen gas; wherein the flow rate of the nitrogen gas is 2800 m³ / s. 3 / h~5000m 3 / h.

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