Method for producing low-phosphorus steel through converter single-slag method
By performing specific treatment of molten iron before converter smelting and adopting staged oxygen supply and slag production operations during the smelting process, the problem that the single slag method is difficult to control the phosphorus content in low-phosphorus steel is solved, and efficient production of low-phosphorus steel is achieved and Cost reduction.
Patent Information
- Application Number
- CN202411599320.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-02-18
AI Technical Summary
When using the converter single slag method to produce low-phosphorus steel, it is difficult to effectively control the phosphorus content in the steel output, especially when it needs to be controlled below 0.005%, which is more difficult.
By performing specific treatment of molten iron before converter smelting, including adjusting the mass content and temperature of Si, and using a phased oxygen supply strategy and appropriate amount of white ash to make slag during converter smelting, the final slag alkalinity of slag is controlled and timing to achieve low phosphorus steel production.
This method can effectively reduce the content of impurities such as P in low-phosphorus steel, improve the control of phosphorus in low-phosphorus steel by single slag method, achieve the goal of producing low-phosphorus steel by using single slag method, and at the same time reduce smelting costs and smelting cycle.
Smart Images
Figure CN119464610A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of steel smelting, and in particular to a method for producing low-phosphorus steel using a converter single-slag process. Background Art
[0002] For most steels, phosphorus in steel is a very harmful element, and the lower the requirement, the better. The main function of the oxygen converter is dephosphorization. At present, the main methods for producing converter low-phosphorus steel are single slag dephosphorization and double slag dephosphorization. The double slag method improves the dephosphorization effect of the early blowing, pours the dephosphorization slag out of the converter at the end of the early blowing, reduces the phosphorus content of the entire converter system, and further dephosphorizes in the later decarburization and blowing stage to achieve the purpose of producing low-phosphorus steel; the double slag mode is simple to operate and the phosphorus content is easier to control. However, the double slag mode has a high production efficiency and low cost. The production of low-phosphorus steel using the converter single slag method can save production cycles, improve efficiency, and reduce production costs. However, the single slag method can only stably control the phosphorus content of steel output to within 0.015%, and it is difficult to control it below 0.005%. Summary of the invention
[0003] The present application provides a method for producing low-phosphorus steel by a converter single-slag process, so as to improve the control of phosphorus in the low-phosphorus steel by the single-slag process.
[0004] The present application provides a method for producing low-phosphorus steel by a converter single-slag method, the method comprising:
[0005] Obtain molten iron;
[0006] The molten iron is subjected to converter smelting by a single slag method to obtain molten steel;
[0007] tapping the molten steel to obtain low-phosphorus steel;
[0008] Wherein, before the converter smelting, the mass content of Si in the molten iron is 0.20% to 0.50%, and the temperature of the molten iron is 1360° C. to 1420° C.;
[0009] The oxygen supply of the converter smelting includes a first oxygen supply stage and a second oxygen supply stage. The first oxygen supply stage is before TSC measurement, and the second oxygen supply stage is after TSC measurement. The oxygen supply flow rate of the first oxygen supply stage is 4200Nm 3 / h~48000Nm 3 / h, the oxygen supply flow rate of the second oxygen supply stage is 1000Nm 3 / h~1400Nm 3 / h;
[0010] During the converter smelting process, lime is added for slag making; the amount of lime added is 10000kg / furnace to 14000kg / furnace; the final slag basicity of the slag making is 5.0 to 6.0; the timing of slag making is: TSC measurement results meet: the mass content of C in the molten iron is 0.10% to 0.20%, the mass content of P in the molten iron is ≤0.005%, and the temperature of the molten iron is 1550°C to 1570°C.
[0011] As an optional implementation manner, the mass content of C in the molten steel produced is ≤0.03%; and / or
[0012] The mass content of P in the tapped molten steel is ≤0.002%.
[0013] As an optional implementation manner, the temperature of the molten steel being tapped is 1590°C to 1610°C.
[0014] As an optional implementation manner, the steel tapping port is used ≤120 times.
[0015] As an optional implementation, during the converter smelting process, ore is added to the molten iron to adjust the temperature of the molten iron.
[0016] As an optional implementation manner, the amount of ore added is more than 2 tons.
[0017] As an optional implementation, during the converter smelting process, fluorite is added to the molten iron to promote slag formation.
[0018] As an optional implementation manner, the amount of fluorite added is ≤800kg / furnace.
[0019] As an optional implementation manner, before the converter smelting, the mass content of Si in the molten iron meets 0.30% to 0.40%; and / or
[0020] Before the converter smelting, the temperature of the molten iron is 1380°C to 1400°C.
[0021] As an optional embodiment, the amount of lime added is 11000kg / furnace to 13000kg / furnace; and / or
[0022] The final slag basicity of the slag making is 5.3 to 5.7; and / or
[0023] The timing of slag making is: TSC measurement results satisfy: the mass content of C in the molten iron is 0.13% to 0.17%, the mass content of P in the molten iron is ≤0.004%, and the temperature of the molten iron is 1555° C. to 1565° C.
[0024] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0025] The method provided in the embodiment of the present application can give full play to the dephosphorization efficiency of the converter through the mutual coordination of parameters such as molten iron raw materials, slag making operation, and blowing operation, thereby reducing smelting costs and smelting cycles, reducing the content of impurity elements such as P in low-phosphorus steel, improving the control of phosphorus in low-phosphorus steel by the single slag method, and realizing the production of low-phosphorus steel by the single slag method. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0028] Figure 1 A flowchart of the method provided in the embodiment of the present application. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0030] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0031] Figure 1 A flow chart of the method provided in the embodiment of the present application is as follows: Figure 1 As shown, the embodiment of the present application provides a method for producing low-phosphorus steel by a converter single slag method, the method comprising:
[0032] S1. Get molten iron;
[0033] In some embodiments, before the converter smelting, the mass content of Si in the molten iron is 0.20% to 0.50%, and the temperature of the molten iron is 1360° C. to 1420° C. Further, before the converter smelting, the mass content of Si in the molten iron meets 0.30% to 0.40%; the temperature of the molten iron is 1380° C. to 1400° C.
[0034] Exemplarily, before the converter smelting, the mass content of Si in the molten iron can be 0.2%, 0.3%, 0.4%, 0.5%, etc., and it can also be any value in the range of 0.20% to 0.50%. The temperature of the molten iron can be 1360°C, 1370°C, 1380°C, 1390°C, 1400°C, 1410°C, 1420°C, etc., and it can also be any value in the range of 1360°C to 1420°C.
[0035] S2. The molten iron is smelted in a converter by a single slag method to obtain molten steel;
[0036] In some embodiments, the oxygen supply for converter smelting includes a first oxygen supply stage and a second oxygen supply stage, wherein the first oxygen supply stage is before TSC measurement, and the second oxygen supply stage is after TSC measurement, and the oxygen supply flow rate of the first oxygen supply stage is 4200 Nm 3 / h~48000Nm 3 / h, the oxygen supply flow rate of the second oxygen supply stage is 1000Nm 3 / h~1400Nm 3 / h.
[0037] For example, the oxygen supply flow rate in the first oxygen supply stage may be 4200 Nm 3 / h、8000Nm 3 / h、12000Nm 3 / h、16000Nm 3 / h、20000Nm 3 / h、24000Nm 3 / h、28000Nm 3 / h、32000Nm 3 / h、36000Nm 3 / h、40000Nm 3 / h、44000Nm 3 / h、48000Nm 3 / h, etc., which can also be 4200Nm 3 / h~48000Nm 3 The oxygen supply flow rate in the second oxygen supply stage can be 1000Nm 3 / h、1100Nm 3 / h、1200Nm3 / h、1300Nm 3 / h、1400Nm 3 / h, etc., it can also be 1000Nm 3 / h~1400Nm 3 Any value within the range of / h.
[0038] In some embodiments, lime is added to the converter smelting process for slag formation; the amount of lime added is 10,000 kg / furnace to 14,000 kg / furnace; and the basicity of the final slag is 5.0 to 6.0.
[0039] For example, the amount of lime added can be 10000 kg / furnace, 11000 kg / furnace, 12000 kg / furnace, 13000 kg / furnace, 14000 kg / furnace, etc., and it can also be any value in the range of 10000 kg / furnace to 14000 kg / furnace. The final slag basicity of slag making can be 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, etc., and it can also be any value in the range of 5.0 to 6.0.
[0040] In some embodiments, the timing of slag making is: TSC measurement results meet: the mass content of C in the molten iron is 0.10% to 0.20%, the mass content of P in the molten iron is ≤0.005%, and the temperature of the molten iron is 1550°C to 1570°C. Further, the amount of lime added is 11000kg / furnace to 13000kg / furnace; the final slag basicity of the slag making is 5.3 to 5.7; the timing of slag making is: TSC measurement results meet: the mass content of C in the molten iron is 0.13% to 0.17%, the mass content of P in the molten iron is ≤0.004%, and the temperature of the molten iron is 1555°C to 1565°C.
[0041] In some embodiments, during the converter smelting process, ore is added to the molten iron to adjust the temperature of the molten iron. Furthermore, the amount of ore added is more than 2 tons.
[0042] In some embodiments, during the converter smelting process, fluorite is added to the molten iron to promote slag formation. Furthermore, the amount of fluorite added is ≤800kg / furnace.
[0043] S3. tapping the molten steel to obtain low-phosphorus steel;
[0044] In some embodiments, the mass content of C in the molten steel of the tapped steel is ≤0.03%; the mass content of P in the molten steel of the tapped steel is ≤0.002%.
[0045] In some embodiments, the temperature of the molten steel during the tapping is 1590° C. to 1610° C. Exemplarily, the temperature of the molten steel during the tapping may be 1590° C., 1595° C., 1600° C., 1605° C., 1610° C., etc., and may also be 1590° C. to 1610° C.
[0046] In some embodiments, the tapping port is used ≤120 times, so that the inner port can be smooth, thereby avoiding slag rolling during the tapping process.
[0047] The method can give full play to the dephosphorization efficiency of the converter through the mutual coordination of parameters such as molten iron raw materials, slag making operation, and blowing operation, thereby reducing smelting costs and smelting cycles, reducing the content of impurity elements such as P in low-phosphorus steel, improving the control of phosphorus in low-phosphorus steel by the single slag method, and realizing the production of low-phosphorus steel by the single slag method.
[0048] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.
[0049] Example 1
[0050] A method for producing low-phosphorus steel by a converter single-slag process, the method comprising:
[0051] S1. Get molten iron;
[0052] S2. The molten iron is smelted in a converter by a single slag method to obtain molten steel;
[0053] S3. tapping the molten steel to obtain low-phosphorus steel;
[0054] Molten iron requirements: Si: 0.35%, T: 1390℃.
[0055] The blowing oxygen flow rate is 20000Nm 3 / h, bottom blowing flow after TSC is adjusted to 1200Nm 3 / h;
[0056] Slag making operation: the amount of lime (high calcium lime) added is 10000-14000kg / furnace depending on the Si content of molten iron, the basicity of the final slag is controlled at about 5.0-6.0, and the slag is well formed during the process; the temperature is adjusted with ore (ore amount is more than 2t), and fluorite ≤800kg / furnace is added to promote slag formation.
[0057] End point control: ①TSC measurement target: C% content 0.15%, T = 1560℃, P target ≤ 0.005%; add ore and lime according to TSC measurement results; ②Blowing end point target: C% ≤ 0.03%, P% ≤ 0.002%; T = 1600℃. Equal TSO steel sample phosphorus content is produced.
[0058] Comparative Example 1
[0059] Production of Low Phosphorus Steel by Double Slag Method
[0060] The lime consumption, molten iron loss and production cycle of each embodiment and comparative example are shown in the following table:
[0061] White ash consumption t / furnace Molten iron loss t / furnace Production cycle / min Example 1 8.2 1.2 45 Comparative Example 1 9.7 2.5 53
[0062] It can be seen from the above table that the single slag smelting method provided by the embodiment of the present application is adopted, and the steel smelting cycle is reduced from about 53 minutes to about 45 minutes, and the smelting cycle is reduced by about 10 minutes per furnace. According to the calculation of 200 furnaces of steel smelting per year, the production time can be shortened by 2000 minutes. According to the calculation of 36 minutes of smelting cycle of ordinary steel grades, the potential production capacity can be increased by 55.6 furnaces. The furnace output is calculated based on an average of 218t and a benefit of 200 yuan per ton, and a potential production capacity benefit of 2.424 million yuan can be obtained. In addition, there are certain cost reduction benefits for energy consumption, steel material alloy consumption, etc.
[0063] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0064] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b and c can be single or multiple.
[0065] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for producing low-phosphorus steel by a converter single-slag process, characterized in that: The method comprises: Obtain molten iron; The molten iron is subjected to converter smelting by a single slag method to obtain molten steel; tapping the molten steel to obtain low-phosphorus steel; Wherein, before the converter smelting, the mass content of Si in the molten iron is 0.20% to 0.50%, and the temperature of the molten iron is 1360° C. to 1420° C.; The oxygen supply of the converter smelting includes a first oxygen supply stage and a second oxygen supply stage. The first oxygen supply stage is before TSC measurement, and the second oxygen supply stage is after TSC measurement. The oxygen supply flow rate of the first oxygen supply stage is 4200Nm 3 / h~48000Nm 3 / h, the oxygen supply flow rate of the second oxygen supply stage is 1000Nm 3 / h~1400Nm 3 / h; During the converter smelting process, lime is added for slag making; the amount of lime added is 10000kg / furnace to 14000kg / furnace; the final slag basicity of the slag making is 5.0 to 6.0; the timing of slag making is: TSC measurement results meet: the mass content of C in the molten iron is 0.10% to 0.20%, the mass content of P in the molten iron is ≤0.005%, and the temperature of the molten iron is 1550°C to 1570°C.
2. The method for producing low-phosphorus steel by the converter single slag method according to claim 1, characterized in that: The mass content of C in the molten steel produced is ≤0.03%; and / or The mass content of P in the tapped molten steel is ≤0.002%.
3. The method for producing low-phosphorus steel by the converter single slag method according to claim 1, characterized in that: The temperature of the molten steel during the tapping is 1590°C to 1610°C.
4. The method for producing low-phosphorus steel by the converter single slag method according to claim 1, characterized in that: The steel tapping port is used ≤120 times.
5. The method for producing low-phosphorus steel by the converter single-slag method according to claim 1, characterized in that: During the converter smelting process, ore is added to the molten iron to adjust the temperature of the molten iron.
6. The method for producing low-phosphorus steel by the converter single-slag method according to claim 5, characterized in that: The amount of ore added is more than 2t.
7. The method for producing low-phosphorus steel by the converter single-slag method according to claim 1, characterized in that: During the converter smelting process, fluorite is added to the molten iron to promote slag formation.
8. The method for producing low-phosphorus steel by the converter single-slag method according to claim 7, characterized in that: The added amount of the fluorite is ≤800kg / furnace.
9. The method for producing low-phosphorus steel by the converter single-slag method according to claim 1, characterized in that: Before the converter smelting, the mass content of Si in the molten iron meets 0.30% to 0.40%; and / or Before the converter smelting, the temperature of the molten iron is 1380°C to 1400°C.
10. The method for producing low-phosphorus steel by the converter single-slag method according to claim 1, characterized in that: The amount of lime added is 11000kg / furnace to 13000kg / furnace; and / or The final slag basicity of the slag making is 5.3 to 5.7; and / or The timing of slag making is: TSC measurement results satisfy: the mass content of C in the molten iron is 0.13% to 0.17%, the mass content of P in the molten iron is ≤0.004%, and the temperature of the molten iron is 1555° C. to 1565° C.