Method for inhibiting splashing in smelting process of converter with high scrap ratio
By optimizing the coordinated control of oxygen supply and slag formation processes, the splashing problem in the converter smelting process under high scrap ratios was solved, achieving stable suppression of splashing and improved production safety.
Patent Information
- Application Number
- CN202511980364.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-03-17
AI Technical Summary
Under high scrap ratio conditions, splashing during converter smelting is difficult to suppress stably. Existing technologies are slow to react and cannot accurately respond to drastic kinetic changes, resulting in the loss of steel material and heat, which endangers safe production.
By optimizing the coordinated control of the oxygen supply system and the slag-forming system, including adjusting the oxygen lance position and oxygen supply intensity at different stages, and adding slag-forming materials in batches during the middle and later stages of blowing, slag with a certain degree of alkalinity and foaminess is formed, and the reaction process of the molten pool is steadily controlled.
It effectively suppresses splashing in converters with high scrap ratios, reduces metal and heat loss, improves metal yield, extends equipment life, and ensures safe production.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of iron and steel metallurgy, and specifically relates to a method for suppressing splashing during high scrap ratio converter smelting. Background Technology
[0002] Converter steelmaking is the main process in modern steel production. Currently, increasing the scrap ratio in converters has become a key technological direction for reducing molten iron consumption, carbon emissions, and production costs. However, the introduction of a high scrap ratio has brought severe challenges to converter smelting, the most prominent of which is splashing.
[0003] A high scrap ratio leads to a low initial molten pool temperature in the converter. Melting scrap requires a large amount of heat, which can easily cause uneven temperature and composition in the molten pool and delay the carbon-oxygen reaction. In the later stages of blowing, as the overall temperature of the molten pool rises, the previously suppressed carbon-oxygen reaction may erupt suddenly, generating a large amount of CO gas. When the gas generation rate far exceeds the rate at which it is discharged through the slag layer, it causes the foamy slag to rise rapidly and eventually overflow violently from the furnace mouth, forming a large splash. This splash not only causes significant losses of steel and heat, exacerbates furnace lining erosion, and increases energy consumption, but also poses a serious threat to safe production.
[0004] Currently, existing technologies generally control the process reaction by empirically adjusting the oxygen lance position and adding slag-forming materials in batches. However, under high scrap steel ratio conditions, the traditional control mode is slow to react and cannot accurately cope with the drastic changes in kinetic conditions caused by the concentrated melting of scrap steel, and the effect of suppressing splashing is unstable.
[0005] Therefore, there is an urgent need for a converter operation method to suppress process splashing in the smelting of high scrap steel ratios. Summary of the Invention
[0006] The purpose of this invention is to address the problem of unstable control over converter splashing under high scrap ratio smelting conditions in converter steelmaking, and to provide a method for suppressing splashing during high scrap ratio converter smelting. This method is effective in suppressing converter splashing under high scrap ratio (≥25%) smelting conditions. Specifically, by optimizing the synergistic control of the oxygen supply and slag-forming processes, precise intervention in the molten pool reaction process is achieved, thereby fundamentally suppressing splashing.
[0007] The technical solution of this invention is as follows: A method for suppressing splashing during high scrap ratio converter smelting includes the following steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 20-30 kg / t; Then, slag splashing is carried out to protect the furnace; after slag splashing is completed, scrap steel and molten iron are loaded in sequence, and the scrap steel ratio is controlled to be ≥25%.
[0008] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing (<2.5 min): Gun position controlled at 1250-1350 mm; oxygen supply intensity controlled at 2.10-2.35 Nm. 3 / (t·min). Following this procedure will ensure stable heating of the molten pool during this stage, promoting the melting of scrap steel.
[0009] Mid-stage of blowing (2.5-4.0 min): Gun position controlled at 1550-1650 mm; oxygen supply intensity controlled at 3.3-3.6 Nm. 3 / (t·min).
[0010] This stage is the critical intervention period. Coupling the lance position and oxygen supply intensity according to the aforementioned relationship not only ensures large-area agitation of the molten pool and accelerates the formation of FeO in the slag to promote further melting of the slag and scrap steel, but also ensures that the carbon-oxygen reaction proceeds under controlled conditions rather than being delayed and then erupted, thereby suppressing the occurrence of splashing.
[0011] Late stage of blowing (after 4 minutes): Gun position controlled at 1350-1450mm; oxygen supply intensity controlled at 3.6-3.8 Nm. 3 / (t·min).
[0012] 1-2 minutes before the blowing reaches the end point, the gun position is pressed down to below 1200mm to effectively uniformize the temperature and steel composition.
[0013] In the later stages of refining, the coupling between the gun position and the oxygen supply intensity can better balance the reaction and cause the temperature to rise evenly.
[0014] The slag-making process is carried out as follows: During the middle stage of blowing, the first batch of slag-forming material is added while the lance position is raised to 1550-1650mm.
[0015] The first batch of slag-forming materials includes the following components: 8-10 kg / t of dolomite; 3-15 kg / t of ore; and lime. The amount of lime added in the first batch of slag-forming materials is 50%-70% of the total amount of lime required.
[0016] This allows for the rapid formation of slag with a certain degree of alkalinity and foaminess in the highly oxidizing atmosphere created during the mid-stage of smelting.
[0017] Based on the total oxygen blowing time, the remaining lime is added in batches when the blowing time reaches 25%-40% of the total blowing time.
[0018] The above operations suppress foamy splashing during this stage and ensure that the slag alkalinity gradually increases.
[0019] In this invention, the method for suppressing splashing during the high scrap ratio converter smelting process involves, during the slag-forming process, after 50% of the total blowing time has elapsed, if the temperature is sufficient, ore can be added in batches, with each batch ≤ 5.0 kg / t and a time interval ≥ 30 seconds.
[0020] This operation aims to "fine-tune" the temperature and stabilize the reaction process through continuous and gentle cooling, smoothly controlling the rate of temperature rise in the molten pool during the later stages of blowing. If the temperature is insufficient, no more materials are added.
[0021] In this invention, the method for suppressing splashing during the high scrap ratio converter smelting process involves adding the remaining lime in 2-5 batches during the slag-forming process.
[0022] In this invention, the method for suppressing splashing during the high scrap ratio converter smelting process, wherein the temperature of the molten iron added in step (1) is 1380-1430℃.
[0023] In this invention, the method for suppressing splashing during high scrap ratio converter smelting process has a silicon content of ≤0.7% in the molten iron added in step (1).
[0024] In this invention, the method for suppressing splashing during the high scrap ratio converter smelting process contains the following components (wt%) in the molten iron in step (1): C 4.5-5.3%, Si 0.25-0.55%, Mn 0.15-0.25%, P 0.110-0.125%, S 0.005-0.015%.
[0025] The beneficial effects of this invention are as follows: The method for suppressing splashing during high scrap ratio converter smelting described in this invention has the following advantages: 1. By adopting the oxygen supply strategy of "slow movement in the early stage, strong stirring in the middle stage, and stable operation in the later stage", the carbon-oxygen reaction that is prone to stagnation and concentration under high scrap ratio is actively guided and controlled, so that it is released at a relatively high but controllable rate in the middle stage of blowing, avoiding the cumulative explosion of the reaction in the later stage of blowing, and fundamentally eliminating the power source of large splashes.
[0026] 2. By closely coupling the oxygen supply system with the slag-forming system, a large amount of ore is added during the mid-stage of blowing, which not only promotes slag formation but also balances the heat of the concentrated reaction. This synergistic control makes the entire blowing process more stable, and the splash suppression effect is significant and stable.
[0027] 3. It effectively reduces metal and heat loss caused by splashing, improves metal yield and endpoint hit rate, reduces production costs, and extends the life of equipment such as furnace lining and oxygen lance, ensuring safe production. Detailed Implementation
[0028] The technical solution of the present invention will be described in detail below, taking the smelting of 5 heats of steel in a 120t top and bottom blowing converter as an example.
[0029] Example 1 The method for suppressing splashing during high scrap ratio converter smelting includes the following specific steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 22 kg / t ± 2 kg / t.
[0030] Then, slag splashing is carried out to protect the furnace; after the slag splashing is completed, 35.08t of scrap steel and 109.85t of molten iron are loaded in sequence, and the scrap steel ratio is controlled at 31.9%.
[0031] The molten iron added was at a temperature of 1396℃ and contained the following components: C 4.58%, Si 0.33%, Mn 0.17%, P 0.123%, and S 0.012%.
[0032] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing: lance position controlled at 1258mm; oxygen supply intensity controlled at 2.22Nm. 3 / (t·min).
[0033] Mid-stage of blowing: lance position controlled at 1555mm; oxygen supply intensity controlled at 3.36Nm. 3 / (t·min).
[0034] In the later stages of blowing: the lance position is controlled at 1440mm; the oxygen supply intensity is controlled at 3.78Nm. 3 / (t·min).
[0035] One minute before the blowing reaches the end point, the gun position is pressed down to below 1200mm.
[0036] The slag-making process is carried out as follows: During the middle stage of smelting, the first batch of slag-forming material is added when the gun position is raised to 1555mm. The first batch of slag-forming material consists of the following components: 1113kg (8kg / t) of dolomite; 396kg (3kg / t) of ore; and 2052kg of lime (60% of the total amount added).
[0037] When the blowing process has lasted 4-6 minutes, add the remaining 40% of the lime in 4 batches. Details are as follows: When the blowing process reaches 4 minutes and 20 seconds, add a second batch of 456 kg of lime.
[0038] When the blowing process reaches 4 minutes and 55 seconds, add the third batch of lime, 512 kg.
[0039] When the blowing process reaches 5 minutes and 36 seconds, add the fourth batch of lime, 399 kg.
[0040] Example 2 The method for suppressing splashing during high scrap ratio converter smelting includes the following specific steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 26 kg / t ± 2 kg / t.
[0041] Then, slag splashing is carried out to protect the furnace; after the slag splashing is completed, 36.12t of scrap steel and 108.86t of molten iron are loaded in sequence, and the scrap steel ratio is controlled at 33.2%.
[0042] The molten iron added was at a temperature of 1401℃ and contained the following components: C 5.12%, Si 0.53%, Mn 0.23%, P 0.117%, and S 0.006%.
[0043] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing: lance position controlled at 1333mm; oxygen supply intensity controlled at 2.18Nm. 3 / (t·min).
[0044] Mid-stage of blowing: lance position controlled at 1600mm; oxygen supply intensity controlled at 3.45Nm. 3 / (t·min).
[0045] In the later stages of blowing: the lance position is controlled at 1380mm; the oxygen supply intensity is controlled at 3.66Nm. 3 / (t·min).
[0046] One minute before the blowing reaches the end point, the gun position is pressed down to below 1200mm.
[0047] The slag-making process is carried out as follows: During the middle stage of smelting, the first batch of slag-forming material is added when the lance position is raised to 1600mm. The first batch of slag-forming material consists of the following components: 1170kg (8.1kg / t) of dolomite; 896kg (6.2kg / t) of ore; and 2222kg of lime (53% of the total amount added).
[0048] When the blowing process has lasted 4-6 minutes, add the remaining 47% of the lime in 5 batches. Details are as follows: When the blowing reaches 4 minutes and 12 seconds, add a second batch of 512 kg of lime.
[0049] When the blowing process reaches 4 minutes and 33 seconds, add the third batch of lime, 506 kg.
[0050] When the blowing process reaches 5 minutes and 16 seconds, the fourth batch of lime, 523 kg, is added.
[0051] When the blowing process reaches 5 minutes and 46 seconds, the fifth batch of lime, 426 kg, is added.
[0052] Example 3 The method for suppressing splashing during high scrap ratio converter smelting includes the following specific steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 27 kg / t ± 2 kg / t.
[0053] Then, slag splashing is carried out to protect the furnace; after the slag splashing is completed, 35.18t of scrap steel and 111.36t of molten iron are loaded in sequence, and the scrap steel ratio is controlled at 31.6%.
[0054] The molten iron added was at a temperature of 1396℃ and contained the following components: C 4.99%, Si 0.34%, Mn 0.17%, P 0.12%, S 0.002%.
[0055] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing: lance position controlled at 1300mm; oxygen supply intensity controlled at 2.30Nm. 3 / (t·min).
[0056] Mid-stage of blowing: lance position controlled at 1600mm; oxygen supply intensity controlled at 3.38Nm. 3 / (t·min).
[0057] In the later stages of blowing: the lance position is controlled at 1400mm; the oxygen supply intensity is controlled at 3.7Nm. 3 / (t·min).
[0058] One minute before the blowing reaches the end point, the gun position is pressed down to below 1200mm.
[0059] The slag-making process is carried out as follows: During the middle stage of smelting, the first batch of slag-forming material is added when the lance position is raised to 1600mm. The first batch of slag-forming material consists of the following components: 1157kg (8kg / t) of dolomite; 826kg (5.6kg / t) of ore; and 1925kg of lime (60.8% of the total amount added).
[0060] When the blowing process has lasted 4-6 minutes, add the remaining 39.2% lime in 4 batches. Details are as follows: When the blowing process reaches 4 minutes and 33 seconds, add a second batch of 456 kg of lime.
[0061] When the blowing reaches 4 minutes and 55 seconds, add the third batch of 400 kg of lime.
[0062] When the blowing process reaches 5 minutes and 36 seconds, add the fourth batch of lime, 386 kg.
[0063] Example 4 The method for suppressing splashing during high scrap ratio converter smelting includes the following specific steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 28 kg / t ± 2 kg / t.
[0064] Then, slag splashing is carried out to protect the furnace; after the slag splashing is completed, 35.06t of scrap steel and 112.36t of molten iron are loaded in sequence, and the scrap steel ratio is controlled at 31.2%.
[0065] The molten iron added was at a temperature of 1423℃ and contained the following components: C 4.68%, Si 0.55%, Mn 0.21%, P 0.113%, and S 0.012%.
[0066] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing: lance position controlled at 1330mm; oxygen supply intensity controlled at 2.20Nm. 3 / (t·min).
[0067] Mid-stage of blowing: lance position controlled at 1630mm; oxygen supply intensity controlled at 3.58Nm. 3 / (t·min).
[0068] Late stage of blowing: lance position controlled at 1430mm; oxygen supply intensity controlled at 3.65Nm. 3 / (t·min).
[0069] One minute before the blowing reaches the end point, the gun position is pressed down to below 1200mm.
[0070] The slag-making process is carried out as follows: During the middle stage of smelting, the lance position is raised to 1630mm while the first batch of slag-forming material is added. The first batch of slag-forming material consists of the following components: 1235kg (8.4kg / t) of dolomite; 666kg (4.5kg / t) of ore; and 2500kg of lime (56.7% of the total amount added).
[0071] When the blowing process has lasted 4-6 minutes, add the remaining 43.3% lime in 5 batches. Details are as follows: When the blowing process reaches 4 minutes and 10 seconds, add a second batch of 456 kg of lime.
[0072] When the blowing process reaches 4 minutes and 43 seconds, add the third batch of lime, 512 kg.
[0073] When the blowing process reaches 5 minutes and 10 seconds, add the fourth batch of lime, 429 kg.
[0074] When the blowing process reaches 5 minutes and 10 seconds, add the fifth batch of lime, 512 kg.
[0075] Example 5 The method for suppressing splashing during high scrap ratio converter smelting includes the following specific steps: (1) Residue retention and loading: After the previous furnace taps steel, a portion of the final slag is reserved in the furnace, with a slag retention amount of 23 kg / t ± 2 kg / t.
[0076] Then, slag splashing is carried out to protect the furnace; after the slag splashing is completed, 33.85t of scrap steel and 112.12t of molten iron are loaded in sequence, and the scrap steel ratio is controlled at 30.2%.
[0077] The molten iron added was at a temperature of 1386℃ and contained the following components: C 5.23%, Si 0.28%, Mn 0.17%, P 0.125%, and S 0.008%.
[0078] (2) Converter blowing: The oxygen supply system shall be operated as follows: Early stage of blowing: lance position controlled at 1290mm; oxygen supply intensity controlled at 2.19Nm. 3 / (t·min).
[0079] Mid-stage of blowing: lance position controlled at 1560mm; oxygen supply intensity controlled at 3.5Nm. 3 / (t·min).
[0080] Late stage of blowing: lance position controlled at 1380mm; oxygen supply intensity controlled at 3.67Nm. 3 / (t·min).
[0081] One minute before the blowing reaches the end point, the gun position is pressed down to below 1200mm.
[0082] The slag-making process is carried out as follows: During the middle stage of smelting, the first batch of slag-forming material is added when the lance position is raised to 1560mm. The first batch of slag-forming material consists of the following components: 1248kg (8.5kg / t) of dolomite; 586kg (4.0kg / t) of ore; and 1922kg of lime (60.1% of the total amount added).
[0083] When the blowing process has lasted 4-6 minutes, add the remaining 39.9% lime in 4 batches. Details are as follows: When the blowing process reaches 4 minutes and 20 seconds, add the second batch of lime, 403 kg.
[0084] When the blowing process reaches 4 minutes and 55 seconds, the third batch of lime, 487 kg, is added.
[0085] When the blowing process reaches 5 minutes and 36 seconds, add the fourth batch of lime, 388 kg.
[0086] Comparative Example 1 The difference from Example 1 is that the oxygen supply system is operated as follows: Early stage of blowing: lance position controlled at 1758mm; oxygen supply intensity controlled at 3.22Nm. 3 / (t·min).
[0087] Mid-stage of blowing: lance position controlled at 1555mm; oxygen supply intensity controlled at 3.78Nm. 3 / (t·min).
[0088] Late stage of blowing: lance position controlled at 1440mm; oxygen supply intensity controlled at 3.36Nm. 3 / (t·min).
[0089] The others are the same as in Example 1.
[0090] Comparative Example 2 The difference from Example 1 is that the oxygen supply system is operated as follows: Early stage of blowing: lance position controlled at 1800mm; oxygen supply intensity controlled at 3.33Nm. 3 / (t·min).
[0091] Mid-stage of blowing: lance position controlled at 1530mm; oxygen supply intensity controlled at 3.36Nm. 3 / (t·min).
[0092] In the later stages of blowing: the lance position is controlled at 1440mm; the oxygen supply intensity is controlled at 3.78Nm. 3 / (t·min).
[0093] The others are the same as in Example 1.
[0094] Comparative Example 3 The difference from Example 1 is that the slag-forming process is carried out as follows: The first batch of slag-forming materials consisted of the following: 1113 kg (8 kg / t) of dolomite; 396 kg (3 kg / t) of ore; and 2564 kg of lime (75% of the total amount).
[0095] When the blowing reaches 4 minutes and 20 seconds, add the remaining 25% of lime, which is the second batch of lime, 855 kg.
[0096] The others are the same as in Example 1.
[0097] Table 1. Splashing phenomena during the converter smelting process in each embodiment and comparative example.
[0098] Therefore, it can be seen that the converter blowing process carried out according to the method of the present invention is stable and free from any splashing.
Claims
1. A method of suppressing spitting in a high scrap ratio converter smelting process, characterized in that, The method comprises the following steps: (1) slagging and charging: After the previous furnace is tapped, a part of the final slag is reserved in the furnace, and the amount of the reserved slag is 20-30 kg / t; Then, the slag splashing is performed, and after the slag splashing is completed, scrap steel and molten iron are sequentially charged, and the ratio of the scrap steel is controlled to be greater than or equal to 25%; (2) converter blowing: The oxygen supply system is operated as follows: Early stage of blowing: gun position controlled at 1250-1350 mm; oxygen supply intensity controlled at 2.10-2.35 Nm 3 (t·min); Middle stage of blowing: gun position is controlled at 1550-1650 mm; oxygen supply intensity is controlled at 3.3-3.6 Nm 3 (t·min); Late blowing stage: gun position controlled at 1350-1450 mm; oxygen supply intensity controlled at 3.6-3.8 Nm 3 (t·min); Before blowing to the end point, the lance position is pressed to be lower than 1200 mm; The slagging system is operated as follows: In the middle of blowing, the lance position is lifted to 1550-1650 mm, and the first batch of slagging materials is added; The first batch of slagging materials comprises the following components: 8-10 kg / t of dolomite, 3-15 kg / t of ore, and lime, and the amount of the lime added in the first batch of slagging materials is 50%-70% of the total amount of the lime required to be added; According to the total oxygen blowing time, the remaining lime is added in batches at 25%-40% of the total blowing time.
2. A method of suppressing spitting in a high scrap ratio converter smelting process according to claim 1, characterized in that, In the operation process of the slagging system, the remaining lime is added in 2-5 batches.
3. A method of suppressing spitting in a high scrap ratio converter smelting process according to claim 1, characterized in that, The temperature of the molten iron added in the step (1) is 1380-1430 ℃.
4. A method of suppressing spitting in a high scrap ratio converter smelting process according to claim 1, characterized in that, The silicon content of the molten iron added in the step (1) is less than or equal to 0.7%.
5. The method of suppressing spitting in a high scrap ratio converter smelting process according to claim 1, characterized in that, The molten iron added in the step (1) contains the following components: C 4.5-5.3%, Si 0.25-0.55%, Mn 0.15-0.25%, P 0.110-0.125%, and S 0.005-0.015%.