Method for accurately controlling refining slag system

Abstract

The invention belongs to the technical field of steel smelting, and particularly relates to a method for accurately controlling a refining slag system. Comprising the following steps: (1) confirming a converter deoxidation mode and used materials in advance, and ensuring that the types and the quantity of the required materials must be true; (2) performing theoretical slag system measurement and calculation on the added materials, tapping strip slag, ladle erosion slag and silicon oxidation amount of the converter through a slag system calculation model in combination with steel grade requirements during refining, and measuring and calculating the adding quantity of residual materials according to a target slag system and the slag system calculation model; and (3) adding the materials into the steel ladle in batches according to the measurement and calculation result and the process requirements, paying attention to the change of slag conditions, re-measuring and calculating by using a slag system calculation model if the materials need to be supplemented, and balancing the materials according to the slag system requirements. Rapid switching of slag systems with different steel grade requirements can be achieved, the stability of the refining final slag system can be improved, and it is guaranteed that components and quality of molten steel are stable and controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting, and in particular relates to a method for accurately controlling a refined slag system. Background Art

[0002] In steel smelting, because different steel grades have different requirements for the refining slag system, there are many types of pre-melted refined slag. Different batches may produce different steel grades in the actual steelmaking production process. The general steel plant is equipped with limited silos, and it is impossible to allow the silos to store a variety of refined slags with different contents, which is not conducive to the precise control of the slag system of the final refined slag when the steel grade is switched. In the actual production process, pre-melted slag is only used as one of the production materials. In order to meet the production needs, lime, fluorite, alloys, aluminum products, etc. are also needed for steelmaking. In addition, some converter slag will inevitably enter the ladle during the converter steelmaking process, which leads to the final refined slag system not being affected by one of the materials or one factor. Changes. Since pre-melted slag is only one of the materials in the steelmaking process, the workers cannot accurately judge the changes in the slag system in the actual operation process, and thus cannot accurately control the terminal slag system. In addition, the production cost of pre-melted refined slag is generally high, and it is generally difficult to use it in large quantities in actual use. Summary of the invention

[0003] The object of the present invention is to provide a method for accurately controlling the refined slag system to solve the problems existing in the prior art.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A method for accurately controlling a refined slag system comprises the following steps:

[0006] (1) Confirm the converter deoxidation method and materials used in advance, and require that the material types and quantities must be true;

[0007] (2) Refining: The theoretical slag system is calculated based on the slag system calculation model for the materials added to the converter, the slag in the steel strip, the ladle erosion slag, and the amount of silicon oxide according to the steel grade requirements. The amount of remaining materials to be added is calculated based on the target slag system and the slag system calculation model.

[0008] (3) Based on the calculation results, each material is added to the ladle in batches according to the process requirements, and the changes in slag conditions are paid attention to. If additional materials are needed, the slag system calculation model is used to recalculate and perform material balance according to the slag system requirements.

[0009] Furthermore, the slag in the steel strip in step (2) is part of the slag that is carried out with the molten steel when the molten steel is poured from the converter into the ladle or other container;

[0010] Ladle erosion slag is the molten slag produced after the refractory material of the ladle is eroded;

[0011] The amount of silicon oxidation is the amount of SiO2 produced by oxidation of Si added to the converter;

[0012] The theoretical slag system is the slag system composition from the converter to the refining furnace in theory. The components of the theoretical slag system include but are not limited to CaO, SiO2, Al2O3, and MgO;

[0013] The target slag system is the slag system composition expected to be achieved after refining in the refining furnace. The components of the target slag system include but are not limited to CaO, SiO2, Al2O3, and MgO. The quantity of each component of the target slag system is determined according to the type of steel.

[0014] Furthermore, the slag system calculation model includes statistics on the content of each component of the input and calculation of the quantity of each component of the output. The components of the input include but are not limited to CaO, SiO2, Al2O3, Al, and MgO.

[0015] Furthermore, the method for calculating the component quantities of CaO and MgO in the output is that the content of CaO and MgO in each input multiplied by the quantity of each input is the component quantity of CaO and MgO in each input, and the component quantities of CaO and MgO in each input are added together to obtain the component quantity of CaO and MgO in the output.

[0016] Furthermore, the method for calculating the component quantity of SiO2 in the output is to multiply the component quantity of Si in the input by 2.43, where 2.43 is an empirical constant, that is, the silicon oxidation amount.

[0017] Furthermore, the method for calculating the amount of Al2O3 components in the output is to multiply the content of Al in each input by the amount of each input by 1.85, where 1.85 is an empirical constant, to obtain the amount of Al2O3 components produced by the Al in each input;

[0018] The content of Al2O3 in each input is multiplied by the quantity of each input to obtain the component quantity of Al2O3 in each input. The sum of the component quantity of Al2O3 produced by Al in each input and the component quantity of Al2O3 in each input is the component quantity of Al2O3 in the output.

[0019] The present invention has the following beneficial effects:

[0020] 1. It can realize the rapid switching of slag system required by different steel grades, which is beneficial to improve the stability of the final slag system of refining and ensure the stable control of molten steel composition and quality.

[0021] 2. Realizing the rapid comprehensive utilization of materials within the factory is conducive to expanding the idea of ​​comprehensive utilization of materials, minimizing the use of refined slag and modifiers, revitalizing waste materials, and reducing manufacturing costs.

[0022] 3. Enable operators to quickly judge and adjust the final slag system, especially the operation transition speed when quickly switching steel grades or adjusting material types. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the slag system phase diagram of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] A method for accurately controlling a refined slag system comprises the following steps:

[0026] (1) Confirm the converter deoxidation method and materials used in advance, and require that the material type and quantity must be true.

[0027] The deoxidation method of the converter is the deoxidizer method, and the materials added mainly include AD powder, calcium silicon aluminum, aluminum products, lime, fluorite, silicon, etc.

[0028] (2) Refining: Based on the steel grade requirements, the theoretical slag system is calculated for the materials added to the converter, the slag in the steel strip, the ladle erosion slag, and the amount of silicon oxide through the slag system calculation model, and the amount of remaining materials to be added is calculated based on the target slag system and the slag system calculation model.

[0029] The statistics of the contents of various components of the input materials of the theoretical slag system are shown in Table 1 below:

[0030] Table 1: Statistical table of the content of various components of the input materials of the theoretical slag system

[0031] Quantity CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> Al MgO AD powder 0.35 5％ 48％ 30％ Silicon Aluminum Calcium 0.35 26.40％ 59％ 14.50％ Aluminum products 0.13 99.50％ lime 1.55 92％ 1.50％ Slag from steel 0.3 44％ 14％ 1.20％ 7.50％ Ladle erosion 0.3 70％ Silicon Oxidation 0.07 fluorite 0.2 other 0.1

[0032] According to the statistical data in Table 1, the quantity table of each component of the output of the theoretical slag system is calculated, as shown in Table 2:

[0033] Table 2: Quantity of each component in the output of the theoretical slag system

[0034]

[0035] The total slag volume of the theoretical slag system is 3.29t. When calculating the component quantity of SiO2, 0.07t of silicon was input, and the obtained SiO2 was 0.07×2.43=0.17t. Adding the quantity of SiO2 in AD powder, silicon-aluminum-calcium, lime, and steel strip slag, the quantity of SiO2 in the theoretical slag system is 0.46t.

[0036] When calculating the amount of Al2O3 components, the amount of Al in AD powder converted into Al2O3 is 0.35×30%×1.85=0.19t, and the amount of Al in aluminum products converted into Al2O3 is 0.13×99.5%×1.85=0.24t. Adding the amount of SiO2 in AD powder, aluminum products and steel strip slag, the amount of Al2O3 in the theoretical slag system is 0.65t.

[0037] The above calculation method is used to obtain the initial slag composition ratio when the converter is charged with materials and enters the refining process, so as to achieve the theoretical prediction of the initial slag entering the refining station. The CaO, SiO2, and Al2O3 required for the target slag system are accurately added according to the material components used. The target slag system is derived from the actual production and the prediction of multiple projects. The setting of the target slag system in the actual production process is derived from the on-site process requirements. This method is also applicable to the test use of various new materials and the adjustment process of the slag system.

[0038] (3) Based on the calculation results, each material is added to the ladle in batches according to the process requirements, and the changes in slag conditions are paid attention to. If additional materials are needed, the slag system calculation model is used to recalculate and perform material balance according to the slag system requirements.

[0039] like Figure 1 As shown, taking ordinary low alloy structural steel Q355B as an example:

[0040] The actual production process of Q355B in the early stage was to add top slag lime + fluorite (150kg) + aluminum blocks during the converter steelmaking process, add ferrosilicon and silicon manganese in sequence during the steelmaking process, use aluminum particles to modify the slag in the refining process, and use sodium fluoroaluminate-based slag-making agent and lime to adjust the slag according to the viscosity of the steel slag. The actual refined final slag was sampled and tested to be 53.15% CaO, 9.32% SiO2, 23.02% Al2O3, 6.12% CaF and 6.53% MgO.

[0041] Considering the influence of CaF on the aggravation of ladle erosion, a F reduction test was carried out to improve the life of refractory materials. According to the slag system calculation model, when the converter fluorite is eliminated and the dosage of other materials remains unchanged, the theoretical refining final slag composition is 56.38% CaO, 9.89% SiO2, 24.42% Al2O3, 2.38% CaF, and 6.93% MgO. From the slag system phase diagram, the basicity of the refined slag increases by about 42°C due to the F reduction adjustment. Therefore, it is necessary to adjust the refined slag composition and reselect the low-fluorine and low-melting point area. The phase diagram shows that the theoretical composition of the slag system in the same melting point area under the low F component is about 51% CaO, 12% SiO2, 25% Al2O3, and 6.36% MgO. Then the slag composition is the target slag system, and the types and quantities of all materials are recalculated based on this target. When the converter and refining station enter, they are added according to the calculated values ​​and the melting effect of the refined slag is actually tracked.

[0042] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should all fall within the scope of protection of the present invention.

[0043] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A method for accurately controlling a refined slag system, characterized in that: The following steps are involved: (1) Confirm the converter deoxidation method and materials used in advance, and require that the material types and quantities must be true; (2) Refining: The theoretical slag system is calculated based on the slag system calculation model for the materials added to the converter, the slag in the steel strip, the ladle erosion slag, and the amount of silicon oxide according to the steel grade requirements. The amount of remaining materials to be added is calculated based on the target slag system and the slag system calculation model. (3) Based on the calculation results, each material is added to the ladle in batches according to the process requirements, and the changes in slag conditions are paid attention to. If additional materials are needed, the slag system calculation model is used to recalculate and perform material balance according to the slag system requirements.

2. The method for accurately controlling the refined slag system according to claim 1, characterized in that: The slag in the step (2) is part of the slag that is carried out with the molten steel when the molten steel is poured from the converter into the ladle or other container; Ladle erosion slag is the molten slag produced after the refractory material of the ladle is eroded; The amount of silicon oxidation is the amount of SiO2 produced by oxidation of Si added to the converter; The theoretical slag system is the slag system composition from the converter to the refining furnace in theory. The components of the theoretical slag system include but are not limited to CaO, SiO2, Al2O3, and MgO; The target slag system is the slag system composition expected to be achieved after refining in the refining furnace. The components of the target slag system include but are not limited to CaO, SiO2, Al2O3, and MgO. The quantity of each component of the target slag system is determined according to the type of steel.

3. The method for accurately controlling the refined slag system according to claim 2, characterized in that: The slag system calculation model includes statistics on the content of each component of the input and calculation of the quantity of each component of the output. The input components include but are not limited to CaO, SiO2, Al2O3, Al, and MgO.

4. The method for accurately controlling the refined slag system according to claim 3, characterized in that: The method for calculating the component quantity of CaO and MgO in the output is that the content of CaO and MgO in each input multiplied by the quantity of each input is the component quantity of CaO and MgO in each input, and the component quantity of CaO and MgO in each input is added together to obtain the component quantity of CaO and MgO in the output.

5. The method for accurately controlling the refined slag system according to claim 4, characterized in that: The method for calculating the component quantity of SiO2 in the output is to multiply the component quantity of Si in the input by 2.43, wherein 2.43 is an empirical constant, i.e., the silicon oxidation amount.

6. The method for accurately controlling the refined slag system according to claim 5, characterized in that: The method for calculating the amount of Al2O3 components in the output is to multiply the content of Al in each input by the amount of each input by 1.85, where 1.85 is an empirical constant, to obtain the amount of Al2O3 components produced by the Al in each input; The content of Al2O3 in each input is multiplied by the quantity of each input to obtain the component quantity of Al2O3 in each input. The sum of the component quantity of Al2O3 produced by Al in each input and the component quantity of Al2O3 in each input is the component quantity of Al2O3 in the output.

Images