A method and apparatus for adding lightly calcined dolomite in a converter

Abstract

This application provides a method and apparatus for adding lightly calcined dolomite to a converter, comprising: after the previous heat of slag has been discharged, rotating the converter to the steel-tapping direction by a first preset tilting angle so that the converter is ready to receive the next heat of scrap steel; adding lightly calcined dolomite to the converter for slag formation; before the steel is tapped from the converter, continuing to add lightly calcined dolomite to the converter for slag thickening; rotating the converter to the charging direction by a second preset tilting angle so that scrap steel can be charged in the next heat, wherein the charging direction is the converter opposite to the steel-tapping direction. This application, by rotating the converter at the first and second preset tilting angles during the solid waste mixing process to add lightly calcined dolomite, and by adding lightly calcined dolomite before the steel is tapped from the converter for effective slag thickening, reduces the mechanical impact of solid waste, slows down slag scouring, ensures normal slag splashing and furnace protection, and effectively maintains the furnace lining.

Description

Technical Field

[0001] This invention belongs to the field of converter steelmaking technology, and in particular provides a method and apparatus for adding lightly calcined dolomite in a converter. Background Technology

[0002] Solid waste resources in the steelmaking process include hot metal pretreatment slag, steelmaking slag, and ladle casting residue, etc. These solid waste resources contain 40-70% Fe and have high recycling value. The converter process, as an effective unit for utilizing solid waste resources, allows resources such as slag iron and slag steel to replace scrap steel in the furnace smelting, achieving efficient recycling. Domestic steel companies all have smelting processes that incorporate solid waste resources into their converters. However, when converters incorporate slag steel and slag iron, factors such as the amount of slag and FeO carried by the slag iron and slag steel can lead to an increase in the amount of slag in the furnace and an increase in slag oxidizability. This exacerbates the erosion of the converter lining during smelting and also results in thinner slag and slower slag removal during slag splashing protection, worsening the slag splashing protection effect and ultimately leading to a rapid lining erosion rate, affecting the control of the converter's blast furnace life. Currently, there are no effective operational and technical guidelines for maintaining the furnace lining when converters incorporate solid waste resources. Summary of the Invention

[0003] The embodiments of this application provide a method and apparatus for adding lightly calcined dolomite to a converter. By rotating the converter at a first preset tilting angle and a second preset tilting angle during the solid waste feeding process, lightly calcined dolomite is added to the converter. Lightly calcined dolomite is also added before the converter taps steel to effectively thicken the slag, thereby reducing the mechanical impact of solid waste, slowing down slag scouring, ensuring normal slag splashing and furnace protection, and effectively maintaining the furnace lining.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] According to one aspect of the embodiments of this application, a method for adding lightly calcined dolomite in a converter is provided, comprising:

[0006] After the previous batch of slag has been discharged, the converter is rotated to the steel tapping direction according to the first preset tilting angle so that the converter can be ready to receive the next batch of scrap steel.

[0007] Lightly calcined dolomite is added to the converter for slag formation;

[0008] Before the steel is tapped from the converter, lightly calcined dolomite is added to the converter to thicken the slag.

[0009] The converter is rotated to the charging direction according to the second preset tilting angle so that scrap steel is charged into the furnace. The charging direction is the direction in which the converter is opposite to the tapping direction.

[0010] In some embodiments of this application, the addition of lightly calcined dolomite to the converter for slag formation includes:

[0011] The amount of lightly calcined dolomite to be added is determined based on the total amount of the original slag-forming material.

[0012] The amount of additional light-burned dolomite to be added is determined based on the total amount of solid waste consumed and the pre-set percentage of magnesium oxide in the final slag.

[0013] Add light-burned dolomite to the converter according to the sum of the required amount of light-burned dolomite and the additional amount of light-burned dolomite.

[0014] In some embodiments of this application, the determination of the additional amount of light-burned dolomite based on the total amount of solid waste and the pre-set percentage of target magnesium oxide in the final slag is determined according to the following formula:

[0015]

[0016] In the formula, m Dolo The weight of the additional lightly calcined dolomite required to characterize the amount, in kg; w AimMgO The mass percentage of target MgO in the final converter slag; W represents the weight of the mixed solid waste, in kg; η represents the mass percentage of iron in the solid waste, w DoloMgO The mass percentage of MgO in lightly calcined dolomite is represented by k1, which represents the first adjustment factor.

[0017] In some embodiments of this application, the parameter w in the formula is... AimMgO The defined range is 10-12%.

[0018] In some embodiments of this application, before the converter tapps, lightly calcined dolomite is added to the converter to thicken the slag, as determined by the following formula:

[0019] m Dolo+ =k2·w [O]

[0020] In the formula, m Dolo+ The weight of lightly calcined dolomite added to the converter before tapping is expressed in kg; w [O] The oxygen activity in the converter, measured before tapping, is expressed in ppm; k2 represents the second adjustment coefficient.

[0021] In some embodiments of this application, k2 is 1.

[0022] In some embodiments of this application, the first preset tilting angle is a tilting angle greater than 30 degrees toward the steel tapping direction.

[0023] In some embodiments of this application, the second preset tilting angle is a tilting angle greater than 60 degrees toward the loading direction.

[0024] The beneficial effects of this application are as follows: by optimizing the tilting angle of the converter during the previous slag dumping and the next scrap steel loading, adding lightly calcined dolomite to the converter for slag formation during the blowing process and adding lightly calcined dolomite to the converter for thickening slag before tapping, the solid waste adhesion is reduced, mechanical impact is mitigated, furnace lining erosion is weakened, and slag splashing and thickening are reduced, ensuring that the furnace lining is effectively maintained during the process of the converter consuming solid waste resources.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0026] 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. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0027] Figure 1 A schematic diagram of the process for adding lightly calcined dolomite in a converter is shown.

[0028] Figure 2 A schematic diagram of the converter structure is shown.

[0029] Reference numerals in the attached figures: 1. Housing; 11. Liner; 12. Rotating shaft. Detailed Implementation

[0030] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0031] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0032] It should be noted that "multiple" in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0033] Combination Figure 1 The diagram shows a flow chart of the method for adding lightly calcined dolomite in a converter.

[0034] This application provides a method for adding lightly calcined dolomite in a converter, including the following steps:

[0035] S1. After the previous furnace slag is discharged, the converter is rotated to the steel tapping direction according to the first preset tilting angle so that the converter can wait for the addition of the next furnace of scrap steel.

[0036] S2. Add lightly calcined dolomite to the converter for slag formation;

[0037] S3. Before the steel is tapped from the converter, continue to add lightly calcined dolomite into the converter for thick slag;

[0038] S4. Rotate the converter to the charging direction according to the second preset tilting angle so that scrap steel is charged into the furnace, wherein the charging direction is the converter away from the tapping direction.

[0039] It is important to understand that by maintaining the converter's rotation angle at the first preset tilt angle during the process of charging scrap steel into the furnace, the mechanical impact of solid waste falling into the furnace on the large furnace lining at the front of the converter can be reduced.

[0040] The beneficial effects of this invention are as follows: by optimizing the tilting angle of the converter during the previous slag dumping and the next scrap steel loading, adding lightly calcined dolomite to the converter for slag formation during the blowing process and adding lightly calcined dolomite to the converter for thickening slag before tapping, the solid waste adhesion is reduced, mechanical impact is mitigated, furnace lining erosion is weakened, and slag splashing and thickening are reduced, ensuring that the furnace lining is effectively maintained during the process of the converter consuming solid waste resources.

[0041] In some embodiments of this application, the addition of lightly calcined dolomite to the converter for slag formation includes:

[0042] The amount of lightly calcined dolomite to be added is determined according to the original slag-forming material.

[0043] The amount of additional light-burned dolomite to be added is determined based on the total amount of scrap steel consumed and the pre-set percentage of magnesium oxide in the final slag.

[0044] Add light-burned dolomite to the converter according to the sum of the required amount of light-burned dolomite and the additional amount of light-burned dolomite.

[0045] It is important to understand that the original slag-forming material itself needs to have light-burned dolomite added to the converter. On this basis, due to the influence of solid waste slag, additional light-burned dolomite needs to be added to balance the magnesium oxide. Therefore, the total amount of light-burned dolomite that needs to be added to the converter during this heat blowing process is the sum of the light-burned dolomite required for the original slag-forming material and the light-burned dolomite required for the solid waste slag.

[0046] In some embodiments of this application, the determination of the additional amount of light-burned dolomite based on the total amount of solid waste and the pre-set percentage of target magnesium oxide in the final slag is determined according to the following formula:

[0047]

[0048] In the formula, m Dolo+ The weight of the additional lightly calcined dolomite required to characterize the amount, in kg; w AimMgO The mass percentage of target MgO in the final converter slag; W represents the weight of the mixed solid waste, in kg; η represents the mass percentage of iron in the solid waste, w DoloMgO The mass percentage of MgO in lightly calcined dolomite is represented by k1, which represents the first adjustment coefficient and can be determined based on factors such as the absorption rate and purity of lightly calcined dolomite.

[0049] It is important to understand that solid waste introduces additional slag along with metallic iron, which increases the total amount of slag in the furnace. The MgO content of this additional slag is extremely low (negligible), and it is necessary to further balance the MgO content of the final slag by adding lightly calcined dolomite.

[0050] In some embodiments of this application, the formula parameter w AimMgO The defined range is 10-12%.

[0051] It is important to understand that for parameter w AimMgO The range of 10-12% is defined to further increase the slag viscosity and reduce the slag erosion of the furnace lining during the smelting process.

[0052] In some embodiments of this application, before the converter tapps, lightly calcined dolomite is added to the converter to thicken the slag, as determined by the following formula:

[0053] m Dolo+ =k2·w [O]

[0054] In the formula, m Dolo+ The weight of lightly calcined dolomite added before tapping, expressed in kg; w [O] The oxygen activity in the converter, measured before tapping, is expressed in ppm; k2 represents the second adjustment coefficient.

[0055] It is important to understand that by utilizing the high-temperature environment inside the furnace during the tapping process to continue melting and lightly calcined dolomite, the MgO content in the slag is further increased, creating conditions for slag splashing to protect the furnace and achieving efficient slag splashing protection.

[0056] In some embodiments of this application, k2 is 1.

[0057] It is important to understand that k2, as the second adjustment coefficient, is positively correlated with mDolo and w[O]. Introducing k2 is to fine-tune the degree of this positive correlation. The optimal value for k2 is around 1, which yields the most suitable amount of lightly calcined dolomite to be added.

[0058] In some embodiments of this application, the first preset tilting angle is a tilting angle greater than 30 degrees toward the steel tapping direction.

[0059] It is important to understand that the converter is tilted at an angle of more than 30 degrees toward the tapping direction to wait for the previous heat to be charged with scrap steel, in order to prevent residual slag from accumulating at the bottom of the front molten pool and causing solid waste resources (hereinafter referred to as solid waste) to stick to the furnace bottom.

[0060] In some embodiments of this application, the second preset tilting angle is a tilting angle greater than 60 degrees toward the loading direction.

[0061] It is important to understand that when loading scrap steel, the converter tilt angle should be maintained at more than 60 degrees towards the front of the furnace to reduce the mechanical impact of solid waste falling into the furnace on the large furnace lining in front of the converter.

[0062] According to one aspect of the embodiments of this application, a converter light-burned dolomite addition device is provided, see [link]. Figure 2 The diagram shows a schematic representation of a converter, the apparatus comprising:

[0063] The converter includes a shell 1, an inner lining 11, and a rotating shaft 12 for rotating the shell 1. The inner lining 11 is located on the inner wall of the shell 1. The converter is located in the tapping direction of the previous furnace and in the charging direction of the next furnace.

[0064] The converter is used to rotate to the tapping direction at a first preset tilting angle after the previous slag tapping is completed, so that the converter can wait for the addition of the next batch of scrap steel. It is also used to add lightly calcined dolomite to the converter for slag formation after the previous batch of scrap steel has been tapped into the converter. Before the steel is tapped from the converter, lightly calcined dolomite is added to the converter to thicken the slag. The converter is also used to rotate to the charging direction at a second preset tilting angle, so that the next batch of scrap steel can be charged. The charging direction is when the converter is opposite to the tapping direction.

[0065] It is important to understand that the original slag-forming process already requires the addition of light-burned dolomite. The converter also consumes solid waste. Furthermore, due to the slag-carrying effect of the solid waste, additional light-burned dolomite is needed to balance the magnesium oxide content. Therefore, the total amount of light-burned dolomite required during this heat's blowing process is the sum of the light-burned dolomite needed for the original slag-forming material and the solid waste. By adding the originally required light-burned dolomite and then consuming solid waste with additional light-burned dolomite, and continuing to add light-burned dolomite before tapping for thick slag, the converter achieves the effects of reducing solid waste adhesion, mitigating mechanical impact, reducing furnace lining erosion, and preventing slag splashing and thickening. This ensures effective maintenance of the furnace lining during the converter's consumption of solid waste resources.

[0066] In some embodiments of this application, an oxygen activity measuring device is also provided inside the housing 1.

[0067] It is important to understand that installing oxygen activity measuring equipment inside the converter ensures real-time monitoring of the oxygen activity content within the converter, thereby determining the amount of lightly calcined dolomite to be added based on the measured oxygen activity level.

[0068] Example 1

[0069] 1. After the previous furnace slag has been discharged, the 210-ton converter is tilted to 40 degrees in the steel tapping direction to await the next furnace to be loaded with scrap steel.

[0070] 2. The target MgO in the final slag of the converter is 12%, and the MgO mass fraction of the light-burned dolomite is 50%. Based on the original slag-forming material calculation (which can be done using a converter secondary model or manually), 3212 kg of light-burned dolomite needs to be added. This furnace consumes 15320 kg of solid waste, with an iron content of 63% (the remainder being slag). Due to the influence of the solid waste on the slag, additional light-burned dolomite needs to be added to balance the target MgO, according to the formula:

[0071]

[0072] In the formula, m Dolo The weight of the additional lightly calcined dolomite required to characterize the amount, in kg; w AimMgO The mass percentage of target MgO in the final converter slag; W represents the weight of the mixed solid waste, in kg; η represents the mass percentage of iron in the solid waste, w DoloMgO The mass percentage of MgO in lightly calcined dolomite is represented by k1, which represents the first adjustment coefficient and can be determined based on factors such as the absorption rate and purity of lightly calcined dolomite.

[0073] Calculations show that an additional 1790 kg of lightly calcined dolomite needs to be added (using the first adjustment factor k1 = 1), and the total amount of lightly calcined dolomite to be added during this furnace blowing process is 5002 kg.

[0074] 3. The oxygen activity in the furnace was measured to be 633 ppm before tapping. According to the formula:

[0075] mDolo+=k2·w[O]

[0076] In the formula, m Dolo+ The weight of lightly calcined dolomite added before tapping from the furnace is expressed in kg; w [O] The oxygen activity in the converter, measured before tapping, is expressed in ppm; k2 represents the second adjustment coefficient.

[0077] Then, add 633 kg of lightly calcined dolomite before tapping (using the second adjustment factor k2 = 1).

[0078] 4. Solid waste is fed into the furnace along with scrap steel. During the process of adding scrap steel to this furnace, the tilting angle of the converter is maintained within the range of 60-70 degrees in the direction in front of the furnace.

[0079] Through the embodiments of the present invention, no solid waste adhesion occurred during the solid waste feeding process in the converter, the mechanical impact of solid waste was reduced, the slag scouring was slowed down, and lightly calcined dolomite was added before tapping to effectively thicken the slag, ensuring normal slag splashing and furnace protection, and the furnace lining was effectively maintained.

[0080] Example 2

[0081] 1. A 210-ton converter is tilted to 35 degrees in the tapping direction to wait for the converter to be loaded with scrap steel from the previous furnace;

[0082] 2. The target MgO in the final slag of the converter is 11%, and the MgO mass fraction of light-burned dolomite is 52%. Based on the original slag-forming material calculation (which can be done using a converter secondary model or manually), 2899 kg of light-burned dolomite needs to be added. This furnace consumes 9980 kg of solid waste, with an iron content of 63% (the remainder being slag). Due to the influence of the solid waste on the slag, additional light-burned dolomite needs to be added to balance the target MgO, according to the formula:

[0083]

[0084] In the formula, m Dolo The weight of the additional lightly calcined dolomite required to characterize the amount, in kg; w AimMgO The mass percentage of target MgO in the final converter slag; W represents the weight of the mixed solid waste, in kg; η represents the mass percentage of iron in the solid waste, w DoloMgO The mass percentage of MgO in lightly calcined dolomite is represented by k1, which represents the first adjustment coefficient and can be determined based on factors such as the absorption rate and purity of lightly calcined dolomite.

[0085] Calculations show that an additional 1089 kg of lightly calcined dolomite needs to be added (using the first adjustment factor k1 = 1.1). The total amount of lightly calcined dolomite that needs to be added during this furnace blowing process is 3988 kg.

[0086] 3. The oxygen activity in the converter was measured to be 778 ppm before tapping. According to the formula:

[0087] m Dolo+ =k2·w [O]

[0088] In the formula, m Dolo+ The weight of lightly calcined dolomite added before tapping from the furnace is expressed in kg; w [O] The oxygen activity in the converter, measured before tapping, is expressed in ppm; k2 represents the second adjustment coefficient.

[0089] Then add 700 kg of lightly calcined dolomite before tapping from the converter (using the second adjustment coefficient k2 = 0.9).

[0090] 4. Solid waste from the converter is fed into the lower furnace along with scrap steel. During the process of adding scrap steel to the lower furnace, the converter tilting angle is maintained within the range of 65-75 degrees in the direction in front of the furnace.

[0091] Through the embodiments of the present invention, no solid waste adhesion occurred during the solid waste feeding process in the converter, the mechanical impact of solid waste was reduced, the slag scouring was slowed down, and lightly calcined dolomite was added before tapping to effectively thicken the slag, ensuring normal slag splashing and furnace protection, and the furnace lining was effectively maintained.

[0092] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0093] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0095] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0096] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method of adding lightly calcined dolomite to a converter, characterized in that, The application relates to a method for controlling the addition of light-burned dolomite in a converter, comprising the following steps: After the slagging of the previous furnace is completed, the converter is rotated to the tapping direction according to a first preset tilting angle, so that the converter is ready for the addition of scrap steel of the next furnace; The converter is rotated to the charging direction according to a second preset tilting angle, so that the next furnace is charged with scrap steel, wherein the charging direction is opposite to the tapping direction; After the previous furnace is tapped, light-burned dolomite is added to the converter for slagging, comprising the following steps: The amount of light-burned dolomite to be added is determined according to the total amount of the original slagging material; The amount of additional light-burned dolomite is determined according to the total amount of the solid waste and the preset percentage of magnesium oxide in the final slag target; Light-burned dolomite is added to the converter according to the sum of the required amount of light-burned dolomite and the additional amount of light-burned dolomite; Before the tapping of the converter, the amount of light-burned dolomite to be added is determined according to the oxygen activity content in the converter, and light-burned dolomite is continuously added to the converter for thickening of the slag, so that the light-burned dolomite is melted in the high-temperature environment of the converter during the tapping process.

2. The method of claim 1, wherein, The amount of additional light-burned dolomite is determined according to the following formula: wherein characterizes the weight of light-burned dolomite that needs to be added, in kg; characterizes the target MgO mass percentage of the converter final slag; characterizes the weight of the solid waste to be added, in kg; characterizes the mass percentage of iron in the solid waste, characterizes the mass percentage of MgO in the light-burned dolomite, characterizes the first adjustment coefficient.

3. The method of adding according to claim 2, wherein, The parameters in the formula The interval is defined as 10-12%.

4. The method of claim 1, wherein the additive is a mixture of a first additive and a second additive. The continuously added light-burned dolomite for thickening of the slag is determined according to the following formula: in which characterizes the weight of light-burned dolomite added to the converter before tapping, in kg; characterizes the oxygen activity measured in the converter before tapping, in ppm; characterizes the second adjustment coefficient.

5. The method of adding according to claim 4, wherein, is equal to 1.

6. The method of adding of claim 1, wherein, The first preset tilting angle is greater than 30 degrees towards the tapping direction.

7. The method of adding of claim 1, wherein, The second preset tilting angle is greater than 60 degrees towards the charging direction.

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