Method and system for optimizing refining slag component control process in refining process

Abstract

The invention provides a refining slag component control process optimization method and system in the refining process, and relates to the technical field of ferrous metallurgy steelmaking. The refining slag component control technology optimization method in the refining process comprises the following steps that S1, molten steel component and weight information is collected in real time; s2, inputting raw and auxiliary material components and cost parameters; s3, setting a refining slag component control target; and S4, calculating the adding quantity of the raw and auxiliary materials based on an extreme value optimal method. According to the method, the molten steel component information and the molten steel weight information are collected in real time, the optimal refining slag component control target and the lowest production cost of the current production steel grade are comprehensively considered, and scientific, reasonable and accurate guidance is provided for the adding type and number of raw and auxiliary materials in the refining process; the method is beneficial to improving the fluidity of the refining slag, improving the capability of removing impurities such as non-metallic inclusions in steel, reducing the production cost of enterprises and improving the product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of iron and steel metallurgy and steelmaking, and in particular to a method and system for optimizing the process of controlling the composition of refined slag in a refining process. Background Art

[0002] Refining slag plays an important role in the smelting process of molten steel. Refining slag can cover the surface of molten steel to prevent oxidation caused by contact between molten steel and air, adsorb and remove non-metallic inclusions in steel, remove impurities such as sulfur and oxygen in steel, and reduce heat loss of molten steel. Therefore, in the refining process, it is necessary to ensure that the refining slag has good fluidity so that it can completely cover the surface of molten steel to reduce oxidation of molten steel. At the same time, it is also necessary to ensure that the refining slag has good adsorption and removal capabilities for non-metallic inclusions and impurity elements such as oxygen and sulfur.

[0003] The refined slag of molten steel is mainly composed of CaO, Al2O3, MgO and SiO2. The composition of the refined slag has a great influence on its properties. In the actual refining process, the refined slag has an optimal composition control target. Beyond the target range, the fluidity of the refined slag and the adsorption capacity of impurities such as non-metallic inclusions in the steel will deteriorate rapidly. Therefore, strict control of the refined slag composition is particularly important.

[0004] At present, in the actual refining process, the control of refining slag composition is mostly carried out based on experience, lacking scientific and reasonable guidance, and the refining slag composition control process is unreasonable, which easily leads to incomplete removal of non-metallic inclusions in the refining and continuous casting process, poor cleanliness of molten steel, and reduced product qualification rate. In recent years, benefiting from the rapid development of computer technology, the application of optimization calculation and other technologies to the refining slag control process has achieved accurate and stable control of the refining slag composition, which is of great significance to reducing the production cost of enterprises and improving product quality. Summary of the invention

[0005] In order to address the deficiencies of the existing process, the purpose of the present invention is to provide a method and system for optimizing the control process of refined slag composition during the refining process, which is used to predict the changes in the refined slag composition during the refining process and optimize the refined slag composition control process, so as to achieve optimal control of the refined slag during the refining process, thereby being able to accurately control the refined slag composition and improve the final product quality.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] Specifically, in a first aspect, the present invention provides a method for optimizing a process for controlling the composition of refined slag during a refining process, which comprises the following steps:

[0008] S1, real-time collection of steel composition information and steel liquid weight parameters during the converter steelmaking process from the refining production process database;

[0009] S2. Obtaining the ingredient parameters and cost parameters of each type of raw and auxiliary materials currently added;

[0010] S3, setting the current optimal refined slag composition control target and refined slag quality;

[0011] S4. Based on the steel composition information, steel liquid weight parameters, raw and auxiliary material composition parameters and cost parameters, the optimal raw and auxiliary material types and addition quantities when the production cost is lowest are calculated based on the extreme value optimal principle while ensuring the final composition control target of the refined slag.

[0012] The specific calculation formula is as follows:

[0013] min.C=∑C i m i (1)

[0014]

[0015] m [equi_O] =0.723022*m [Al] 2 -0.0684*m [Al] +0.00254 (5)

[0016] Formulas (2)-(4) are the constraints of formula (1). By solving them, the optimal type and quality of refined slag added in the refining process can be obtained.

[0017] Where, C is the total production cost of refined slag; C i is the cost of raw material i; m i is the added mass of raw material i, in kg; X i is the composition of raw material i, in %; Y is the target composition of raw material i, in %; m total is the total mass of raw materials and auxiliary materials, in kg; m [Al] is the aluminum content in the molten steel, in kg; m steel is the mass of molten steel, in kg; m [initial_O] is the oxygen content of steel tapped from the converter, in %; m [equi_O] It is the equilibrium oxygen content of molten steel, in %.

[0018] Preferably, the refining production process database in step S1 is a primary or secondary database used on-site.

[0019] Preferably, the molten steel composition parameters in step S1 include carbon, silicon, manganese, phosphorus and free oxygen in the molten steel.

[0020] Preferably, the various types of raw and auxiliary materials in step S2 include lime, calcium carbide, flux, pre-melted slag and silicon carbide.

[0021] Preferably, the various types of raw and auxiliary material components in step S2 include Al2O3, CaO, SiO2 and MgO.

[0022] Preferably, in step S4, an SQP algorithm is used to solve the minimum value of the constraint.

[0023] On the other hand, the present invention also provides a refining slag composition control process optimization system during the refining process, which includes a steel composition information and molten steel weight parameter acquisition unit, a raw material and auxiliary material composition parameter and cost parameter acquisition unit, a refining slag composition control target optimization unit, and an optimal raw material and auxiliary material type and addition quantity calculation unit.

[0024] The steel composition information and molten steel weight parameter acquisition unit is used to acquire the steel composition information and molten steel weight parameters of the converter steel tapping process in real time from the refining production process database;

[0025] The raw material component parameter and cost parameter acquisition unit is used to acquire the component parameters and cost parameters of each type of raw material currently added;

[0026] The refined slag composition control target optimization unit is used to set the current optimal refined slag composition control target and refined slag quality;

[0027] The optimal raw and auxiliary material types and addition quantity calculation unit is used to calculate the optimal raw and auxiliary material types and addition quantities when the production cost is lowest based on the extreme value optimal principle according to the steel composition information, the steel liquid weight parameters, the composition parameters and cost parameters of the raw and auxiliary materials, while ensuring the final composition control target of the refined slag.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] (1) The method for optimizing the refined slag composition control process of the present invention collects the refining process data in real time, comprehensively considers the composition of the molten steel and the composition of the raw and auxiliary materials, and determines the optimal type and amount of the raw and auxiliary materials to be added based on the extreme value optimal method with the lowest cost as the optimization adjustment, thereby improving the precision control of the refined slag composition, improving the fluidity of the refined slag and the ability to adsorb and remove impurities such as non-metallic inclusions in the molten steel, which can greatly reduce production costs and improve product quality.

[0030] (2) The refined slag composition control process optimization system provided by the present invention can directly run the above process optimization method, is suitable for on-site use, and can quickly determine the optimal type and quantity of raw and auxiliary materials to be added, thereby improving the degree of precise control of the refined slag composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0032] Figure 2 It is a schematic flow chart of a control system and an optimization method for refining slag composition in a refining process implemented by the present invention;

[0033] Figure 3 2. It is a schematic diagram comparing the components of refined slag according to an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of the composition and size distribution of non-metallic inclusions in steel in an embodiment of the present invention;

[0035] Figure 5 2. It is a schematic diagram comparing the components of refined slag of a comparative example of the present invention;

[0036] Figure 6 It is a schematic diagram of the composition and size distribution of non-metallic inclusions in steel in the comparative example of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0038] The present invention provides a method for optimizing the process of controlling the composition of refined slag during the refining process. Figure 1 As shown, it includes the following steps:

[0039] S1. Real-time collection of steel composition information and steel liquid weight parameters during the converter steel-making process from the production process database. In a specific application process, the production process database in step S1 is a primary or secondary database used on site. The steel liquid composition parameters in step S1 include carbon, silicon, manganese, aluminum and free oxygen in the steel liquid.

[0040] S2. Obtaining the composition parameters and cost parameters of various types of raw and auxiliary materials currently added. In a specific application process, various types of raw and auxiliary materials in step S2 include lime, calcium carbide, flux, pre-melted slag and silicon carbide. The components of various types of raw and auxiliary materials in step S2 include Al2O3, CaO, SiO2 and MgO.

[0041] S3. Setting the current optimal refined slag composition control target and refined slag quality. In the specific application process, the optimal refined slag composition control target and refined slag quality are set according to the refining requirements in actual production.

[0042] S4. Based on the information of molten steel and raw and auxiliary materials, the optimal types and quantities of raw and auxiliary materials to be added when the production cost is lowest are calculated based on the extreme value optimal principle while ensuring the final composition control target of the refined slag.

[0043] The specific calculation formula is as follows:

[0044] min.C=∑Ci m i (1)

[0045]

[0046] m [equi_O] =0.723022*m [Al] 2 -0.0684*m [Al] +0.00254 (5)

[0047] Formulas (2)-(4) are the constraints of formula (1). In the specific application of the present application, formula (2)-(4) are used to solve formula (1) through a computer program to obtain the optimal type and quality of refined slag added when the cost is lowest in the refining process. In one embodiment, the SQP algorithm can be used to solve the minimum value of the constraint. In other embodiments, other methods can also be used to solve the above formula to obtain the optimal type and quality of refined slag added when the cost is lowest in the refining process.

[0048] Where, C is the total production cost of refined slag; C i is the cost of raw material i; m i is the added mass of raw material i, in kg; X i is the composition of raw material i, in %; Y is the target composition of raw material i, in %; m total is the total mass of raw materials and auxiliary materials, in kg; m [Al] is the aluminum content in the molten steel, in kg; m steel is the mass of molten steel, in kg; m [initial_O] is the oxygen content of steel tapped from the converter, in %; m [equi_O] It is the equilibrium oxygen content of molten steel, in %.

[0049] On the other hand, the present invention also provides a refining slag composition control process optimization system during the refining process, which includes a steel composition information and molten steel weight parameter collection unit, a raw and auxiliary material composition parameter and cost parameter acquisition unit, a refining slag composition control target optimization unit, and an optimal raw and auxiliary material type and addition quantity calculation unit.

[0050] The steel composition information and molten steel weight parameter acquisition unit is used to acquire the steel composition information and molten steel weight parameters of the converter steel-tapping process in real time from the refining production process database.

[0051] The raw material component parameter and cost parameter acquisition unit is used to acquire the component parameters and cost parameters of each type of raw material currently added.

[0052] The refined slag composition control target optimization unit is used to set the current optimal refined slag composition control target and refined slag quality.

[0053] The optimal raw and auxiliary material types and addition quantity calculation unit is used to calculate the optimal raw and auxiliary material types and addition quantities when the production cost is lowest based on the extreme value optimal principle according to the steel composition information, the steel liquid weight parameters, the composition parameters and cost parameters of the raw and auxiliary materials, while ensuring the final composition control target of the refined slag.

[0054] Example

[0055] like Figure 2 As shown, this embodiment provides a method and system for controlling the composition of refining slag and optimizing the process during the refining process. This method is used to study the optimal amount of raw and auxiliary materials added during the refining process of a certain type of steel.

[0056] The specific steps include:

[0057] S1. Real-time collection of molten steel composition information and molten steel weight parameters during converter steel tapping from the production process database, as follows:

[0058] The remaining element compositions and proportions in the molten steel are: C: 0.02%, Si: 0.2, Mn: 2%, P: 0.01%, Al: 0.03%, O: 0.03%.

[0059] Molten steel volume: 200t.

[0060] S2. Obtain the ingredient information and cost information of each type of raw and auxiliary materials currently added.

[0061] The raw and auxiliary materials added in the refining process include: lime, calcium carbide, flux, pre-melted slag and modifier. Generally speaking, the price of lime is 0.5 yuan / kg, the price of calcium carbide is 1.5 yuan / kg, the price of flux is 2 yuan / kg, the price of pre-melted slag is 2 yuan / kg, and the price of modifier is 3 yuan / kg.

[0062] In this embodiment, the composition and mass ratio of each raw material are as follows:

[0063] Lime composition: Al2O3: 5%; CaO3: 90%; SiO2: 5%.

[0064] Calcium carbide composition: Al2O3: 10%; CaO3: 80%; SiO2: 5%.

[0065] Flux composition: Al2O3: 50%; CaO3: 40%; SiO2: 10%.

[0066] Pre-slag composition: Al2O3: 40%; CaO3: 40%; SiO2: 20%.

[0067] Modifier composition: Al2O3: 30%; CaO3: 60%; SiO2: 10%.

[0068] S3. Setting the current optimal refined slag composition control target and refined slag quality. In this embodiment, the optimal refined slag composition control target composition and refined slag quality are set as follows:

[0069] In this embodiment, the target components of the refined slag are controlled as follows: Al2O3: 28%; CaO3: 58%; SiO2: 14%.

[0070] The quality control of refined slag is: 2000kg.

[0071] S4. Based on the information of molten steel and raw and auxiliary materials, the optimal types and quantities of raw and auxiliary materials to be added when the production cost is lowest are calculated based on the extreme value optimal principle while ensuring the final composition control target of the refined slag.

[0072] The specific calculation formula is as follows:

[0073] min.C=∑C i m i (1)

[0074]

[0075] m [equi_O] =0.723022*m [Al] 2 -0.0684*m [Al] +0.00254 (5)

[0076] Formulas (2)-(4) are the constraints of formula (1). By solving them, the optimal type and quality of refined slag added in the refining process can be obtained.

[0077] Where, C is the total production cost of refined slag; C i is the cost of raw material i; m i is the added mass of raw material i, in kg; X i is the composition of raw material i, in %; Y is the target composition of raw material i, in %; m total is the total mass of raw and auxiliary materials, in kg; is the mass of Al2O3 in the molten steel, in kg; m [initial_O] is the oxygen content of steel tapped from the converter, ppm; m [equi_O] is the equilibrium oxygen content of molten steel, ppm.

[0078] Formulas (2)-(4) are constraints of formula (1). In the specific application of the present application, formula (1) is solved by a computer program using formulas (2)-(4) to obtain the optimal type and quality of refined slag added when the cost is lowest in the refining process.

[0079] In the specific calculation process, the SQP algorithm can be used to solve the minimum value of the constraint. The solution process specifically includes the following steps:

[0080] 1. Initialization: Select the initial point x0 as the starting working point for solving the minimum production cost.

[0081] 2. Linearization: Use the current operating point to calculate the first-order derivatives of the objective function and constraints, and use these first-order derivatives to construct a linear quadratic programming problem.

[0082] 3. Solve the linear quadratic problem: By solving the linear quadratic programming problem, a step size Δx is obtained, which will be used to update the working point.

[0083] 4. Update the working point: Update the working point x according to the step size Δx and calculate the approximate Lagrange multiplier.

[0084] 5. Set the termination condition: Check whether the updated working point meets the termination condition to determine whether the iteration needs to be terminated. The termination condition can be that the objective function or constraint function does not change much.

[0085] 6. Convergence check: After the iteration is terminated, check whether the final convergence condition is met. If the final convergence condition is not met, return to step 3 and continue iterating until the convergence condition is met.

[0086] The optimal addition amount of raw materials and the lowest production cost calculated in this embodiment are as follows:

[0087] Lime: 400kg, calcium carbide: 400kg, flux: 200kg, pre-melted slag: 1000kg, modifier: 0kg.

[0088] The calculated minimum production cost of refined slag per ton of steel is 1.6 yuan / ton. Therefore, the optimal amount of raw and auxiliary materials calculated this time can be used as the amount of auxiliary materials added in the refining process to ensure optimal performance while meeting target control and ensure that the production cost of refined slag is low. Without increasing production costs, the production process of refined slag can be greatly optimized and the product performance of refined slag can be improved.

[0089] After that, in the refining process, the auxiliary materials are added according to the calculated optimal amount of raw and auxiliary materials. After the raw and auxiliary materials are added, the refining slag samples are taken to analyze the refining slag composition. After the refining is completed, the molten steel samples are taken to analyze the distribution of non-metallic inclusions in the steel. Figure 3 As shown in the figure, the melting point of refined slag is lower than the steelmaking temperature of 1600 degrees Celsius. It can be kept in liquid phase during the steelmaking process, and has strong adsorption capacity and good fluidity for non-metallic inclusions in steel. Figure 4 As shown, from Figure 4 It can be seen that the number density of non-metallic inclusions in steel is 2.97# / mm 2 , with a maximum diameter of 9.24μm.

[0090] Comparative Example

[0091] In this comparative example, the amount of auxiliary materials added is determined entirely according to actual experience. During the refining process, 1200 kg of lime, 400 kg of flux and 200 kg of calcium carbide are added to the surface of the molten steel. After slag removal during the LF refining process, aluminum wire, ferrosilicon, high carbon ferromanganese, ferrochrome and other alloys are added to the molten steel. Argon is blown and stirred throughout the process. The total vacuum time for RH refining is 10-40 min, the deep vacuum time is 15-30 min, and the vacuum argon flow rate is 50-100 Nm 3 / h; soft blowing after breaking the air, calcium treatment operation, feeding calcium line 100-400m, calcium treatment feeding line speed 60-200m / min, soft blowing of molten steel after calcium feeding, soft blowing time 5-15min, soft blowing argon flow rate 10-50NL / min. Take the refining slag sample during the refining process, take the molten steel sample after the refining is completed and water-cooled in time. Afterwards, analyze the refining slag composition and the composition and size distribution of non-metallic inclusions in the steel. The refined slag composition obtained is as follows Figure 5 As shown, from Figure 5 It can be seen that the melting point of the refined slag obtained by this process is relatively high, deviating from the liquid phase, which is not conducive to the adsorption and removal of non-metallic inclusions in steel and the improvement of the cleanliness of molten steel. Figure 6 As shown, from Figure 6 It can be seen that the number density of non-metallic inclusions in steel is 4.90# / mm 2 , the maximum diameter is 19.35 μm. In this embodiment, the control of the refined slag composition is entirely based on human experience. It is not easy to control the amount of auxiliary materials added in the actual production process, especially the excessive amount of lime added, which leads to poor fluidity of the refined slag and poor adsorption capacity for inclusions, and thus makes it impossible to fully remove non-metallic inclusions in the steel, which is not conducive to improving the cleanliness of the molten steel.

[0092] It can be seen from the embodiments and comparative examples that the method for optimizing the refined slag composition control process of the present invention collects refining process data in real time, comprehensively considers the composition of molten steel and the composition of raw and auxiliary materials, and determines the optimal type and quantity of raw and auxiliary materials to be added based on the extreme value optimal method, thereby improving the degree of precise control of the refined slag composition, improving the fluidity of the refined slag and the ability to adsorb and remove impurities such as non-metallic inclusions in the molten steel, which can greatly reduce production costs and improve product quality.

[0093] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for optimizing the process of controlling the composition of refining slag during the refining process, characterized in that: It includes the following steps: S1. Real-time collection of steel composition information and steel liquid weight parameters during converter steel tapping from the production process database; S2. Obtaining the ingredient parameters and cost parameters of each type of raw and auxiliary materials currently added; S3, setting the current optimal refined slag composition control target and refined slag quality; S4. Based on the steel composition information, steel liquid weight parameters, composition parameters and cost parameters of various types of raw and auxiliary materials, the optimal types and amounts of raw and auxiliary materials to be added when the production cost is the lowest are calculated based on the extreme value optimal principle while ensuring the final composition control target of the refined slag. The specific calculation formula is as follows: min.C=∑C i m i (1) m [equi_O] =0.723022*m [Al] 2 -0.0684*m [Al] +0.00254 (5) Formulas (2)-(4) are the constraints of formula (1). By solving them, the optimal type and quality of refined slag added in the refining process can be obtained. Where, C is the total production cost of refined slag; C i is the cost of raw material i; m i is the added mass of raw material i, in kg; X i is the composition of raw material i, in %; Y is the target composition of raw material i, in %; m total is the total mass of raw materials and auxiliary materials, in kg; m [Al] is the aluminum content in the molten steel, in kg; m steel is the mass of molten steel, in kg; m [initial_O] is the oxygen content of steel tapped from the converter, in %; m [equi_O] It is the equilibrium oxygen content of molten steel, in %.

2. The method for optimizing the process of controlling the composition of refined slag in the refining process according to claim 1, characterized in that: The production process database described in step S1 is a primary or secondary database used for processing.

3. The method for optimizing the process of controlling the composition of refined slag in the refining process according to claim 1, characterized in that: The molten steel composition parameters in step S1 include carbon, silicon, manganese, phosphorus and free oxygen in the molten steel.

4. The method for optimizing the process of controlling the composition of refined slag in the refining process according to claim 1, characterized in that: The various types of raw and auxiliary materials described in step S2 include lime, calcium carbide, flux, pre-melted slag and silicon carbide.

5. The method for optimizing the process of controlling the composition of refined slag during the refining process according to claim 1, characterized in that: The various types of raw and auxiliary material components in step S2 include Al2O3, CaO, SiO2 and MgO.

6. The method for optimizing the process of controlling the composition of refined slag in the refining process according to claim 1, characterized in that: In step S4, the SQP algorithm is used to solve the minimum value of the constraint.

7. A process optimization system for the process optimization method for controlling the composition of refined slag in the refining process according to claim 1, characterized in that: It includes a steel composition information and molten steel weight parameter acquisition unit, a raw material and auxiliary material composition parameter and cost parameter acquisition unit, a refined slag composition control target optimization unit, and an optimal raw material and auxiliary material type and addition quantity calculation unit; The steel composition information and molten steel weight parameter acquisition unit is used to acquire the steel composition information and molten steel weight parameters of the converter steel tapping process in real time from the refining production process database; The raw material component parameter and cost parameter acquisition unit is used to acquire the component parameters and cost parameters of each type of raw material currently added; The refined slag composition control target optimization unit is used to set the current optimal refined slag composition control target and refined slag quality; The optimal raw and auxiliary material types and addition quantity calculation unit is used to calculate the optimal raw and auxiliary material types and addition quantities when the production cost is lowest based on the extreme value optimal principle according to the steel composition information, the steel liquid weight parameters, the composition parameters and cost parameters of the raw and auxiliary materials, while ensuring the final composition control target of the refined slag.

8. A device for optimizing the process of controlling the composition of refined slag during the refining process, characterized in that: It includes the process optimization system described in claim 7.

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