A systematic industrial research method for composition evolution and interface mass transfer in ladle refining process

Abstract

This invention proposes a systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining, relating to the field of steelmaking technology in iron and steel metallurgy. The invention includes selecting steel grades sequentially processed through converter, ladle furnace, and continuous casting processes, dividing ladle refining into six stages, and conducting intensive sampling at nine key moments. Composition analysis and inclusion characterization are performed on both steel and slag samples. Based on the test results, the stage-specific changes in the composition, size, and quantity of molten steel, slag, and inclusions are statistically analyzed, and the impact of each process on composition evolution is analyzed. The mass contribution and proportion of magnesium oxide and aluminum oxide in the slag and aluminum and oxygen in the molten steel from various sources are quantified, the dissolution rate of refractory materials is calculated, and the mass transfer mechanism at each interface is analyzed. Through intensive sampling in industrial settings, multi-method detection and analysis, and quantitative calculations, this invention systematically reveals the composition evolution laws and interfacial mass transfer mechanisms throughout the ladle refining process, providing a scientific basis for optimizing refining processes.

Description

Technical Field

[0001] This invention relates to the field of steelmaking technology in iron and steel metallurgy, and in particular to a systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining. Background Technology

[0002] As a core component of secondary metallurgy, the ladle refining furnace is a crucial link between the primary refining process in converters or electric arc furnaces and the continuous casting process, playing an irreplaceable role in modern steel production. Ladle refining possesses multiple core functions, including deoxidation, desulfurization, alloying, homogenization of molten steel temperature, and removal and modification of non-metallic inclusions. Its processing effectiveness directly determines the quality of the continuously cast billet and the performance of the final product.

[0003] The ladle refining process is a typical multiphase reaction system, containing molten steel, slag, refractory materials, gaseous phases (argon, air), and non-metallic inclusions, accompanied by coupled effects of heat, mass, and momentum transfer, as well as complex physicochemical reactions. The evolution of the molten steel composition is jointly controlled by multiple factors, including alloy addition, slag-steel reaction, interaction between ladle refractory materials, and secondary atmospheric oxidation. The formation, growth, removal, and modification of non-metallic inclusions are further influenced by molten steel flow, bubble behavior, slag-steel interfacial reactions, and refractory material dissolution.

[0004] Regarding the ladle refining process, researchers improved desulfurization efficiency and inclusion removal by adjusting the slag-forming regime, controlling the argon blowing intensity, and optimizing the timing of alloy addition. In terms of mechanistic studies, laboratory simulations and numerical calculations were used to explore the kinetics of the steel-slag interface reaction, the collisional growth mechanism of inclusions, and the flow field distribution within the ladle. For detection and analysis, scanning electron microscopy and electron probe microanalysis were used to characterize the morphology, composition, and size of inclusions.

[0005] However, existing research still has the following shortcomings: First, there is a lack of systematic tracking of the entire ladle refining process: existing studies mostly use single-point sampling or sampling at a few moments, which makes it difficult to capture the dynamic evolution of the composition of molten steel, slag, and inclusions during the refining process. In particular, the influence mechanism of key operation nodes (such as slag formation, alloying, strong stirring, calcium treatment, soft blowing, etc.) on composition evolution is still unclear. Second, there is insufficient quantitative analysis of mass transfer at multiple interfaces in the ladle refining system: Ladle refining involves multiple mass transfer interfaces such as the molten steel-slag interface, the slag-refractory material interface, the molten steel-refractory material interface, and the molten steel-bubble interface. The contribution ratio of each interface reaction to the evolution of molten steel composition and inclusions lacks quantitative characterization, making it difficult to accurately determine the dominant role of each mass transfer pathway. Third, the source analysis of key components in steel slag (such as magnesium oxide and aluminum oxide) is not precise enough: magnesium oxide in steel slag can come from converter slag, slag-forming auxiliary materials, steel slag reaction and refractory material dissolution, while aluminum oxide can come from converter slag, slag-forming auxiliary materials, alloy burn-off, inclusion removal and steel slag reaction. However, existing studies lack quantitative distinction of the quality contribution of each source pathway, resulting in an insufficient understanding of the erosion mechanism of refractory materials and the evolution law of inclusions. Fourth, the methods for characterizing inclusions need to be standardized: existing studies mostly use the projected area method or the equivalent diameter method to characterize the size of inclusions, but different studies use different characterization methods, and there is a lack of effective methods to subtract the interference of precipitated phases (such as manganese sulfide) during the cooling process, which leads to biases in the statistical analysis of inclusion composition.

[0006] Based on this, the present invention proposes a systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining to solve the problems existing in the prior art. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to propose a systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining. This invention, through intensive on-site sampling, multi-method detection and analysis, and quantitative calculation, clarifies the composition evolution patterns of molten steel, slag, and inclusions throughout the LF refining process, quantifies the contribution ratio of each interfacial reaction to composition evolution, and reveals the interfacial mass transfer mechanism, providing a scientific basis for optimizing the LF refining process and improving the cleanliness of molten steel.

[0008] To achieve the objectives of this invention, the invention is implemented through the following technical solution: a systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining, comprising the following steps: Step S1, Industrial Trial and Intensive Sampling: Steel grades that have undergone a process involving converter, ladle furnace, and continuous casting were selected. The ladle refining process was then divided into six stages: pre-argon blowing, initial slag formation and alloying, strong argon blowing, composition analysis, secondary slag formation and alloying, and soft blowing. Samples were taken at nine different times: when the ladle entered the refining station, 5 minutes after pre-argon blowing, after initial slag formation and alloying, after strong stirring, before secondary slag formation and alloying, 5 minutes after alloy addition, before calcium treatment, 5 minutes after soft blowing, and after soft blowing. Steel samples were collected from the side furthest from the argon blowing port and 300 mm below the surface of the molten steel. Slag samples were collected using an immersion sampling rod. Step S2, Detection of sample composition and inclusions: The steel and steel slag samples were tested separately. The steel sample was first tested using a direct-reading spectrometer, inductively coupled plasma atomic emission spectrometry, and an oxygen, nitrogen, and hydrogen analyzer to determine the elemental content. Then, the inclusions were analyzed using a scanning electron microscope with an energy dispersive spectrometer. The steel slag sample was tested using X-ray fluorescence spectrometry to determine the composition and low-content components were normalized and removed. Finally, the size and composition of the inclusions were characterized by the equivalent diameter and volume weighted average method. Step S3: Analysis of the evolution of components: Based on the detection results of step S2, the stage changes of sulfur, aluminum and total oxygen in molten steel, the stage changes of calcium oxide, aluminum oxide and magnesium oxide in steel slag, and the stage changes of the composition, size and quantity of inclusions are statistically analyzed. Then, based on the statistical results, the influence of each process on the composition evolution is analyzed. Step S4, Quantitative calculation of interfacial mass transfer: Based on the analysis results of step S3, the mass contribution and proportion of each source pathway of magnesium oxide in steel slag, the mass contribution and proportion of each source pathway of aluminum oxide in steel slag, the mass contribution and proportion of each source pathway of aluminum in molten steel, and the mass contribution and proportion of each source pathway of oxygen in molten steel are quantified. At the same time, the dissolution rate of refractory materials is calculated, and the mass transfer mechanism of each interface is analyzed based on the quantification results and the calculated dissolution rate of refractory materials.

[0009] A further improvement is that, in step S1, the argon flow rate during the pre-blowing and strong argon blowing stages is 0.027 Nm³ / s, and the argon flow rate during the soft blowing stage is 0.0013 Nm³ / s.

[0010] A further improvement is that, in step S1, the sampling furnace is selected from the intermediate furnace in the continuous casting cycle.

[0011] A further improvement is made in step S2, where, when analyzing inclusions using a scanning electron microscope with an energy dispersive spectrometer, the scanning area of ​​each sample is not less than 30 square millimeters, and the volume of manganese sulfide precipitated during the cooling process is deducted when calculating the inclusion composition.

[0012] A further improvement is made in the following way: In step S2, the normalization and removal process for the steel slag sample is specifically as follows: phosphorus pentoxide and titanium dioxide components with a content of less than 0.5% by weight are removed, and the mass fractions of calcium oxide, aluminum oxide, silicon dioxide, magnesium oxide, and manganese monoxide are recalculated.

[0013] A further improvement is made in the following way: In step S2, the specific method for determining the element content is as follows: the carbon, silicon, manganese, phosphorus and sulfur content in the steel sample is determined by a direct-reading spectrometer; the total aluminum, acid-soluble aluminum, total magnesium and total calcium content in the steel sample is determined by inductively coupled plasma atomic emission spectrometry; and the total oxygen content in the steel sample is determined by an oxygen, nitrogen and hydrogen analyzer.

[0014] A further improvement is made in step S3, where the spatial distribution and stage changes of the inclusions are analyzed by the ternary phase distribution diagram of calcium oxide-aluminum oxide-magnesium oxide, and the evolution of the maximum diameter, average diameter, area fraction and number density of the inclusions are statistically analyzed.

[0015] A further improvement is that, in step S4, the sources of magnesium oxide in the steel slag include converter slag feeding, slag-forming auxiliary materials, steel slag reaction, and refractory material dissolution; and the sources of aluminum oxide in the steel slag include converter slag feeding, slag-forming auxiliary materials, alloy burn-off, inclusion removal, and steel slag reaction.

[0016] A further improvement is that, in step S4, the oxygen in the molten steel is obtained through secondary atmospheric oxidation and steel slag reaction, and the oxygen in the molten steel is consumed through inclusion removal and steel slag reaction.

[0017] A further improvement is made in step S4, where the magnesium oxide dissolution rate of the refractory material is calculated at different ladle refining stages, and the dissolution rate of the refractory material at the strong argon blowing stage is the maximum value of the entire process.

[0018] In the process of inclusion characterization, the present invention uses the equivalent diameter to characterize the size of inclusions, and its definition is formula (1), as follows: In the formula, d inc Let A be the equivalent diameter of the inclusion and A be the projected area of ​​the inclusion.

[0019] In the calculation of inclusion composition, the volume of manganese sulfide precipitated during cooling needs to be deducted, and the calculation formula is formula (2), as follows: In the formula, V oxide The actual volume of inclusions after deducting manganese sulfide. V inc The total volume of the inclusions. P oxide The density of the inclusion oxides, W Mns The mass fraction of manganese sulfide in the inclusions. P Mns This represents the density of manganese sulfide.

[0020] The formula for calculating the actual volume of inclusions after deducting manganese sulfide is formula (3), as follows: In the formula, D oxide The equivalent diameter of the inclusions after deducting manganese sulfide is given.V oxide This represents the actual volume of inclusions after deducting manganese sulfide.

[0021] The average composition of inclusions is calculated by a volume-weighted average, and the calculation formula is (4), as follows: In the formula, The first in the inclusions The weighted average mass fraction of the components, V j For the first j The volume of the inclusions V j，i For the first j The first of the impurities i The mass fraction of the components n This represents the total number of inclusions.

[0022] In the quantitative calculation of interfacial mass transfer, since the reaction of steel slag consumes magnesium oxide in the steel slag, the mass of magnesium oxide contributed by the dissolution of refractory materials is equal to the total mass of magnesium oxide in the steel slag minus the amount brought in by slag-forming auxiliary materials plus the amount consumed by the reaction of steel slag. Therefore, this invention uses the mass balance method to quantitatively analyze the source of magnesium oxide in steel slag. The specific calculation formula is formula (5), as follows: In the formula, The mass of magnesium oxide contributing to the dissolution of refractory materials, This represents the total mass of magnesium oxide in the steel slag. The quality of magnesium oxide introduced by the slag-forming auxiliary materials, This represents the mass of magnesium oxide consumed in the steel slag reaction. In step S4, the sources (alloying, slag reaction, inclusions) and consumption pathways of Al in molten steel are analyzed. The mass contribution and proportion of the five major sources of Al2O3 in steel slag (converter slag feeding, slag-forming auxiliary materials, alloy burn-off, inclusion removal, and slag reaction) are quantified, and their calculation formulas are (6) and (7), respectively. Therefore, the consumption of aluminum in molten steel is quantitatively analyzed, and the formula for calculating the mass of aluminum consumed by the slag reaction is (6), as follows: In the formula, The mass of aluminum consumed in the steel slag reaction. This represents the total mass of aluminum in the molten steel. The amount of aluminum added for alloying. The yield of aluminum in the alloy. The mass of aluminum introduced by inclusions.

[0023] The sources of aluminum oxide in steel slag were quantitatively analyzed, and the formula for calculating the mass of aluminum oxide contributed by inclusion removal was given by formula (7), as follows: In the formula, The mass of aluminum oxide contributing to inclusion removal The total mass of aluminum oxide in the steel slag. The quality of aluminum oxide introduced by the slag-forming auxiliary materials, The mass of aluminum oxide produced by the reaction of steel slag. The mass of aluminum oxide produced by alloy burn-off.

[0024] The sources of oxygen in the molten steel in step S4 mainly include three parts: air oxidation, steel slag reaction, and inclusion removal. Inclusion removal has a reducing effect on the oxygen content in the steel, thus allowing for a quantitative analysis of the mass transfer of oxygen in the molten steel. The formula for calculating the amount of oxygen introduced by secondary atmospheric oxidation is formula (8), as follows: In the formula, The amount of oxygen introduced by secondary oxidation in the atmosphere. The total mass of oxygen in the molten steel. To remove the oxygen carried away by the inclusions. This refers to the amount of oxygen introduced or removed during the reaction of steel slag.

[0025] The beneficial effects of this invention are as follows: (1) The present invention divides the ladle refining process into six distinct operation stages and selects nine key moments for intensive sampling, thereby achieving continuous and accurate monitoring of the entire refining process, avoiding the randomness of single-point sampling, and making the experimental data more representative.

[0026] (2) This invention uses a combination of multiple methods such as direct reading spectrometer, inductively coupled plasma atomic emission spectrometry, scanning electron microscope with energy dispersive spectrometer, and X-ray fluorescence spectrometry to achieve full composition analysis of molten steel and slag and microscopic characterization of inclusions. At the same time, the inclusions are standardized and characterized by equivalent diameter and volume weighted average method, resulting in more accurate detection results.

[0027] (3) This invention realizes the quantitative calculation of multi-element interfacial mass transfer in the ladle refining system, clarifies the mass contribution and proportion of magnesium oxide and aluminum oxide in steel slag and aluminum and oxygen in molten steel from various sources, and fills the gap in the existing research on quantitative analysis of interfacial mass transfer.

[0028] (4) The present invention systematically reveals the compositional evolution law of molten steel, slag and inclusions and the interfacial mass transfer mechanism during the ladle refining process, providing accurate theoretical basis and data support for optimizing slag-making process, controlling stirring intensity, inhibiting secondary oxidation and improving the cleanliness of molten steel, and can directly guide industrial production. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the production process of Q295 ordinary carbon steel used in this invention.

[0030] Figure 2 This is a schematic diagram showing the dimensions of the steel ladle and the argon blowing position for industrial testing of this invention.

[0031] Figure 3 This is a schematic diagram of the sampling time and process operation in the LF refining process of the present invention.

[0032] Figure 4 This is a schematic diagram illustrating the changes in elements and inclusions during the refining process of this invention.

[0033] Figure 5 This is a schematic diagram showing the composition and size distribution of inclusions in molten steel during the experiment of this invention.

[0034] Figure 6 This is a schematic diagram illustrating the evolution of inclusions in molten steel during the refining process of this invention.

[0035] Figure 7 This is a schematic diagram of the mass transfer ratio at the interface within the ladle system of this invention.

[0036] Figure 8 This is a schematic diagram of the steps of the present invention. Detailed Implementation

[0037] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0038] according to Figures 1-8 As shown, this embodiment uses Q295 ordinary carbon steel as the research object, with a nominal ladle capacity of 230 tons, equipped with a double-permeable brick argon blowing system. The argon blowing point is 730 mm from the center of the bottom surface of the ladle, and the included angle between the two argon blowing points is 100 degrees. The process flow is converter, ladle furnace, and continuous casting (e.g., ...). Figure 1 (As shown), the dimensions of the ladle and the argon blowing position are as follows: Figure 2 As shown. The specific implementation steps are as follows: Step S1: Industrial Trial and Intensive Sampling Experiments were conducted on intermediate heats within a 10-heat continuous casting cycle. The LF refining process was divided into six stages: pre-blowing argon, initial slagging and alloying, strong argon blowing, composition analysis, secondary slagging and alloying, and soft blowing. Samples were taken at nine time points: when LF entered the station (0 min), 5 min after pre-blowing argon (5 min), after initial slagging and alloying (19 min), after strong stirring (28 min), before secondary slagging and alloying (35 min), 5 min after alloy addition (44 min), before calcium treatment (47 min), 5 min after soft blowing (54 min), and after soft blowing (59 min). Figure 3 (As shown in the figure) The steel sample was collected 300 mm below the surface of the molten steel on the side furthest from the argon blowing port. The steel slag sample was collected using an immersion sampling rod, and the temperature of the molten steel was measured at each time.

[0039] Step S2: Detection of sample composition and inclusions 2.1 Steel Sample Testing: The contents of carbon, silicon, manganese, phosphorus, and sulfur in the steel samples were determined using a direct-reading spectrometer; the contents of total aluminum, acid-soluble aluminum, total magnesium, and total calcium were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES), with a detection limit of 0.0005% by weight; the total oxygen content was determined using an oxygen-nitrogen-hydrogen analyzer; and inclusions were analyzed using a scanning electron microscope with an energy dispersive spectroscopy (EDS) instrument. The scanning area for each sample was 35 square millimeters, and the composition, quantity, and size of the inclusions were recorded. The table below shows the composition of the molten steel at different refining stages. Table 1. Composition of molten steel at different refining stages Note: The detection limit for trace elements is 0.0005 wt%. The total calcium (T.Ca) content in the molten steel at time 0 min is an estimate.

[0040] 2.2 Steel slag sample testing: The contents of calcium oxide, aluminum oxide, silicon dioxide, magnesium oxide, manganese monoxide, phosphorus pentoxide, and titanium dioxide in steel slag were determined by X-ray fluorescence spectrometry. Phosphorus pentoxide and titanium dioxide components with a content of less than 0.5% by weight were removed. The mass fractions of calcium oxide, aluminum oxide, silicon dioxide, magnesium oxide, and manganese monoxide were recalculated. The table below shows the changes in slag composition over time during the refining process. Table 2. Changes in slag composition over time during refining. 2.3 Inclusion characterization: The equivalent diameter of the inclusions was calculated using formula (1), the volume of manganese sulfide precipitated during the cooling process was deducted using formulas (2) and (3), and the average composition of the inclusions was determined by weighted averaging with the volume of the inclusions as the weight using formula (4).

[0041] Step S3: Analysis of the evolution of the composition of molten steel, slag, and inclusions 3.1 Evolution of molten steel composition: The sulfur content was 0.077 wt% in the initial refining stage, decreasing to 0.0135 wt% after strong stirring, and further decreasing to 0.0043 wt% after soft blowing; after the initial alloying, the total aluminum content increased from 0.02 wt% to 0.069 wt%, then decreased back to 0.036 wt% after strong stirring; during the pre-blowing argon stage, the total oxygen content increased from 0.0030 wt% to 0.0043 wt% due to secondary oxidation, then decreased to 0.0024 wt% after alloying due to deoxidation; the total calcium and total magnesium contents remained close to the detection limit throughout the process (e.g., ...). Figure 4 As shown in a and b in the figures), the calcium recovery rate was only 2.06%. 3.2 Evolution of Steel Slag Composition: Upon entering the station, the calcium oxide content was 50.18% by weight, the aluminum oxide content was 35.95% by weight, and the magnesium oxide content was 7.71% by weight. After the initial slag formation, the calcium oxide content increased to 63.99% by weight, and the aluminum oxide content decreased to 21.94% by weight. After the soft blowing process, the magnesium oxide content increased to 11.28% by weight. The contents of silicon dioxide and manganese monoxide continued to decrease due to dilution by the slag-forming agent and the reaction of the steel slag (e.g., ...). Figure 4 As shown in C; 3.3 Inclusion Evolution: In the early stages of refining, inclusions are mainly aluminum oxide. During the vigorous stirring stage, the magnesium oxide content increases significantly, eventually becoming mainly magnesium aluminum spinel, containing trace amounts of calcium oxide, calcium sulfide, and manganese monoxide (such as...). Figure 5 As shown); the maximum diameter of the inclusions ranges from 5 to 40 micrometers, with an average diameter stabilizing at around 2 micrometers. The area fraction and number density increase during the pre-blowing argon stage and then continuously decrease (e.g. Figure 6 As shown, Figure 6 The evolution of (a) maximum diameter, (b) average diameter, (c) area fraction and (d) number density of inclusions in molten steel during the refining process.

[0042] The spatial distribution and stage changes of the composition of inclusions were analyzed by using the ternary phase distribution diagram of calcium oxide-aluminum oxide-magnesium oxide. The evolution of the maximum diameter, average diameter, area fraction and number density of inclusions were statistically analyzed.

[0043] Step S4: Quantitative Calculation of Interfacial Mass Transfer Process 4.1 Mass transfer of magnesia components: The mass of magnesium oxide contributed by refractory dissolution was calculated using formula (5). The proportions of magnesium oxide sources in steel slag were as follows: refractory dissolution 43.5%, slag-forming auxiliary materials 31.6%, converter slag 23.6%, and steel slag reaction 1.4% (e.g., Figure 7 As shown in Figure a, this represents the source of magnesium oxide in the slag; the dissolution rate of magnesium oxide in the refractory material is highest during the strong argon blowing stage, reaching 0.011 tons per minute; 4.2 Aluminum and Alumina Mass Transfer: The mass of aluminum consumed in the steel slag reaction was calculated using formula (6), and the mass of alumina contributed by inclusion removal was calculated using formula (7). The sources of alumina in the steel slag were as follows: converter slag 44.6%, slag-forming auxiliary materials 23.8%, alloy burn-off 12.2%, inclusion removal 9.7%, and steel slag reaction 9.5% (e.g., ...). Figure 7 As shown in Figure b, this represents the source of aluminum oxide in the slag; 43.2% of the aluminum in the molten steel comes from alloying, and 33.6% is consumed by the steel slag reaction (e.g., Figure 7 (As shown in c, this represents the source of aluminum in the slag). 4.3 Oxygen mass transfer: The amount of oxygen introduced by atmospheric secondary oxidation was calculated using formula (8). Atmospheric secondary oxidation is the main pathway for oxygenation of molten steel, while inclusion removal and reaction with slag are the main deoxidation mechanisms, each contributing 50% to deoxidation (e.g., ...). Figure 7 As shown in d, this is the source of oxygen in the slag. Removing inclusions can effectively counteract the oxygenation effect of secondary oxidation. 4.4 Interfacial mass transfer ratio: It is clear that the steel-slag interface is the main mass transfer interface for sulfur, aluminum and oxygen, and the steel slag-refractory material interface is the main mass transfer interface for magnesium oxide. Strong stirring can significantly enhance the mass transfer efficiency of each interface.

[0044] Experimental conclusions The method of this invention has enabled a systematic study of the composition evolution and interfacial mass transfer during the ladle refining process of Q295 steel, and the following conclusions have been drawn: (1) The initial slag formation and strong stirring are the key stages of desulfurization and deoxidation. After the strong stirring is completed, the desulfurization rate slows down and the composition of the molten steel tends to stabilize.

[0045] (2) The main source of magnesium oxide in steel slag is the dissolution of refractory materials, the calcium oxide content is dominated by slag-forming auxiliary materials, and the aluminum oxide content is affected by the flotation of inclusions and the reaction of steel slag.

[0046] (3) Strong stirring is the key node for the transformation of inclusion composition, which can promote the formation of magnesium aluminum spinel and effectively remove large inclusions.

[0047] (4) Suppressing secondary atmospheric oxidation and enhancing the floating of inclusions during the strong stirring stage are the core measures to improve the cleanliness of molten steel.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its framework and scope of application, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining, characterized in that: Includes the following steps: Step S1, Industrial Trial and Intensive Sampling: Steel grades that have undergone a process involving converter, ladle furnace, and continuous casting were selected. The ladle refining process was then divided into six stages: pre-argon blowing, initial slag formation and alloying, strong argon blowing, composition analysis, secondary slag formation and alloying, and soft blowing. Samples were taken at nine different times: when the ladle entered the refining station, 5 minutes after pre-argon blowing, after initial slag formation and alloying, after strong stirring, before secondary slag formation and alloying, 5 minutes after alloy addition, before calcium treatment, 5 minutes after soft blowing, and after soft blowing. Steel samples were collected from the side furthest from the argon blowing port and 300 mm below the surface of the molten steel. Slag samples were collected using an immersion sampling rod. Step S2, Detection of sample composition and inclusions: The steel and steel slag samples were tested separately. The steel sample was first tested using a direct-reading spectrometer, inductively coupled plasma atomic emission spectrometry, and an oxygen, nitrogen, and hydrogen analyzer to determine the elemental content. Then, the inclusions were analyzed using a scanning electron microscope with an energy dispersive spectrometer. The steel slag sample was tested using X-ray fluorescence spectrometry to determine the composition and low-content components were normalized and removed. Finally, the size and composition of the inclusions were characterized by the equivalent diameter and volume weighted average method. Step S3: Analysis of the evolution of components: Based on the detection results of step S2, the stage changes of sulfur, aluminum and total oxygen in molten steel, the stage changes of calcium oxide, aluminum oxide and magnesium oxide in steel slag, and the stage changes of the composition, size and quantity of inclusions are statistically analyzed. Then, based on the statistical results, the influence of each process on the composition evolution is analyzed. Step S4, Quantitative calculation of interfacial mass transfer: Based on the analysis results of step S3, the mass contribution and proportion of each source pathway of magnesium oxide in steel slag, the mass contribution and proportion of each source pathway of aluminum oxide in steel slag, the mass contribution and proportion of each source pathway of aluminum in molten steel, and the mass contribution and proportion of each source pathway of oxygen in molten steel are quantified. At the same time, the dissolution rate of refractory materials is calculated, and the mass transfer mechanism of each interface is analyzed based on the quantification results and the calculated dissolution rate of refractory materials.

2. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S1, the argon flow rate during the pre-blowing and strong argon blowing stages is 0.027 Nm³ / s, and the argon flow rate during the soft blowing stage is 0.0013 Nm³ / s.

3. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S1, the sampling furnace is selected from the intermediate furnace in the continuous casting cycle.

4. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S2, when analyzing inclusions using a scanning electron microscope with an energy dispersive spectroscopy (EDS) instrument, the scanning area of ​​each sample is not less than 30 square millimeters, and the volume of manganese sulfide precipitated during the cooling process is deducted when calculating the inclusion composition.

5. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S2, the normalization and removal process for the steel slag sample is specifically as follows: phosphorus pentoxide and titanium dioxide components with a content of less than 0.5% by weight are removed, and the mass fractions of calcium oxide, aluminum oxide, silicon dioxide, magnesium oxide, and manganese monoxide are recalculated.

6. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S2, the specific method for determining the element content is as follows: the carbon, silicon, manganese, phosphorus and sulfur content in the steel sample is determined by direct reading spectrometer; the total aluminum, acid-soluble aluminum, total magnesium and total calcium content in the steel sample is determined by inductively coupled plasma atomic emission spectrometry; and the total oxygen content in the steel sample is determined by oxygen, nitrogen and hydrogen analyzer.

7. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S3, the spatial distribution and stage changes of the inclusions are analyzed by the ternary phase distribution diagram of calcium oxide-aluminum oxide-magnesium oxide, and the evolution of the maximum diameter, average diameter, area fraction and number density of the inclusions are statistically analyzed.

8. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S4, the sources of magnesium oxide in steel slag include converter slag feeding, slag-forming auxiliary materials, steel slag reaction, and refractory material dissolution. The sources of aluminum oxide in steel slag include converter slag feeding, slag-forming auxiliary materials, alloy burn-off, inclusion removal, and steel slag reaction.

9. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S4, the sources of oxygen in the molten steel are secondary oxidation in the atmosphere and reaction with steel slag, and the sources of oxygen consumption in the molten steel are inclusion removal and reaction with steel slag.

10. The systematic industrial research method for composition evolution and interfacial mass transfer during ladle refining according to claim 1, characterized in that: In step S4, the dissolution rate of magnesium oxide in refractory materials at different ladle refining stages is calculated, and the dissolution rate of refractory materials in the strong argon blowing stage is the maximum value of the whole process.

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