Method for converter steelmaking by using dephosphorization less slag agent

Abstract

The invention discloses a method for converter steelmaking by using a dephosphorization slag-less agent, which comprises the following steps: after a lower gun is ignited normally, materials are added in two batches, the first batch of materials are added within 1.5 minutes, and the first batch of materials comprise lime, light-burned dolomite, pebbles, the dephosphorization slag-less agent and return mine; after feeding of the first batch of materials is finished and primary slag is formed, a second batch of materials are added, the second batch of materials are added within 7 min, and the second batch of materials comprise pebbles and raw dolomite. According to the method, the dephosphorization slag-reducing agent is added, the utilization rate of the converter lime is increased, the converter lime consumption is reduced on the basis of maintaining the current converter endpoint phosphorus control level, and meanwhile, the converter slag material cost and the steel material consumption cost are reduced by replacing part of lime with stones.

Description

Technical Field

[0001] The invention relates to the technical field of converter steelmaking, and in particular to a method for converter steelmaking using a dephosphorization and low-slag agent. Background Art

[0002] In the traditional converter steelmaking method, in order to ensure the dephosphorization effect, high basicity and large slag volume are often required, resulting in increased slag emissions and steel consumption, which not only increases the cost of steelmaking, but also puts pressure on the environment. Considering the national energy conservation and emission reduction policy and the steel mill's own costs, how to reduce the amount of slag generated during steelmaking and improve dephosphorization efficiency is the main research direction at present.

[0003] Based on this, the present invention proposes a method for converter steelmaking using a dephosphorization and low-slag agent, which reduces the amount of slag produced during the steelmaking process, improves the dephosphorization efficiency, reduces the converter lime consumption, and reduces the converter slag cost and steel material consumption cost. Summary of the invention

[0004] In view of the above-mentioned prior art, the purpose of the present invention is to provide a method for converter steelmaking using a dephosphorization and low-slag agent. The present invention improves the utilization rate of converter lime by adding a dephosphorization and low-slag agent. On the basis of maintaining the current converter terminal phosphorus control level, the converter lime consumption is reduced. At the same time, part of the lime is replaced by stone to improve part of the raw material structure ratio, thereby reducing the converter slag cost and steel consumption cost.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention provides a method for converter steelmaking by using a dephosphorization and low-slag agent. After the lower gun is ignited normally, materials are added in two batches. The first batch of materials is added within 1.5 minutes. The first batch of materials includes lime, light-burned dolomite, stone, dephosphorization and low-slag agent and returned ore. After the first batch of materials is added and primary slag is formed, the second batch of materials is added. The second batch of materials is added within 7 minutes. The second batch of materials includes stone and raw dolomite.

[0007] Preferably, the chemical composition of the dephosphorization and slag-reducing agent includes, by weight percentage: Fe2O3 56.7%, CaO 6.19%, Al2O3 10.38%, SiO2 3.88%, MgO 2.56%, Na2O 1.77%, and the remainder includes one or more of Cu, Cr, As and unavoidable impurities.

[0008] Preferably, the particle size of the dephosphorization and low-slag agent is 3-5 cm, and the particle size below 3 mm is less than 5%.

[0009] Preferably, the first batch of materials contains 600-800 kg of lime, 0-400 kg of light-burned dolomite, 0-1000 kg of stone, 300-800 kg of dephosphorization and 0-1000 kg of returned ore.

[0010] Preferably, the second batch of materials contains 800-1500 kg of gravel and 800-2000 kg of raw dolomite.

[0011] Preferably, after the second batch of materials is added, if slag drying occurs, 200-300 kg of dephosphorization and slag reduction agent is added to adjust the slag.

[0012] Preferably, after the first batch of material is added, the gun position is controlled at 1.3-1.4m.

[0013] Preferably, at the end point of smelting, the gun position of the gun pressing is ≤1m, and the gun pressing time is >40s.

[0014] Preferably, the slag amount in each furnace is: when the silicon content in molten iron is less than 0.055%, the slag amount is 1 / 3-1 / 2; when the silicon content in molten iron is greater than 0.55%, no slag is left.

[0015] Beneficial effects of the present invention:

[0016] 1. The present invention improves the utilization rate of converter lime by adding a dephosphorization and slag-reducing agent, and reduces the converter lime consumption while maintaining the current converter endpoint phosphorus control level.

[0017] 2. The reasonable proportion of the chemical components of the dephosphorization and slag-reducing agent of the present invention and the addition of the first batch of materials and the second batch of materials improve the utilization rate of the converter lime. At the same time, by replacing part of the lime with stone, the structural ratio of part of the raw material is improved, thereby reducing the converter slag cost and steel material consumption cost.

[0018] 3. By adding dephosphorization and slag-reducing agent, the slag-forming problem caused by using a certain proportion of stone and dolomite under low iron consumption production conditions is improved, and the problem of slag-forming difficulties leading to gun sticking and affecting the shortening of the smelting cycle is solved. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0020] As introduced in the background technology section, in order to ensure the dephosphorization effect, high alkalinity and large slag volume operations are often required, resulting in increased slag emissions and steel material consumption, which not only increases the cost of steelmaking, but also puts pressure on the environment.

[0021] The present invention improves the utilization rate of converter lime by reasonably mixing the chemical components of the dephosphorization and slag-reducing agent, reduces the converter lime consumption on the basis of maintaining the current converter terminal phosphorus control level, and simultaneously replaces part of the lime with stone to improve part of the raw material structure ratio, thereby reducing the converter slag cost and steel material consumption cost.

[0022] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0023] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0024] The method for making steel in a converter using a dephosphorization and low-slag agent comprises the following steps:

[0025] (1) The dephosphorization and low-slag agent is added through a high-level silo. Empty one high-level silo in advance and then add the dephosphorization and low-slag agent;

[0026] (2) Measure the temperature and take samples of molten iron in each furnace to ensure the accuracy of test conditions; measure the liquid level of the first three furnaces before each shift to ensure the accuracy of the gun position;

[0027] (3) Slag amount in each furnace: if Si in molten iron is less than 0.055%, the slag amount is 1 / 3-1 / 2; if Si in molten iron is greater than 0.55%, no slag is left;

[0028] (4) After the lower gun is ignited normally, the materials are added in two batches. The first batch of materials is added within 1.5 minutes. The first batch of materials includes lime, light-burned dolomite, stone, dephosphorization and slag-reducing agent and return ore. After the first batch of materials is added and the initial slag is formed, the second batch of materials is added. The second batch of materials is added within 7 minutes. The second batch of materials includes stone and raw dolomite. Among them, the chemical composition of the dephosphorization and slag-reducing agent includes, by weight percentage: Fe2O356.7%, CaO 6.19%, Al2O310.38%, SiO23.88%, MgO 2.56%, Na2O 1.77%, and the remainder includes one or more of Cu, Cr, As and unavoidable impurities. The amount of materials added is shown in Table 1:

[0029] Table 1 Material addition amount

[0030]

[0031] (5) After the second batch of materials is added, the drying period is predicted in advance. If slag drying occurs, 200-300 kg of dephosphorization and slag reduction agent is added for slag adjustment;

[0032] (6) Final carbon pulling: Gun position ≤1m, Gun time>40s, Final phosphorus ≤0.010%.

[0033] After replacing part of the lime with stone, the cost of converter auxiliary materials per ton of steel has been reduced from 20.04 yuan / ton before implementation to the current 15.66 yuan (statistical data are shown in Tables 2 and 3). From February to April 2024, the production cost of ordinary carbon steel has been reduced by 1.347 million yuan.

[0034] Table 2 Statistics of unit consumption of auxiliary materials for ordinary carbon steel before project implementation

[0035] materials dolomite Stone lime Unit price (yuan / t) 200.38 39.31 454.48 Average unit consumption (kg / t) 13.72 20.86 15.14 Average unit cost (yuan / t) 3.05 1.02 15.97

[0036] Note: The total unit cost is RMB 20.04 / ton.

[0037] Table 3 Statistics of unit consumption of auxiliary materials for ordinary carbon steel after project implementation

[0038] materials dolomite Stone lime Unit price (yuan / t) 200.38 39.31 454.48 Average unit consumption (kg / t) 9.92 16.79 13.37 Average unit cost (yuan / t) 2.20 0.75 12.71

[0039] Note: The total unit cost is RMB 15.66 / ton.

[0040] In summary, the use of the dephosphorization and low-slag agent of the present invention not only reduces the cost of steelmaking and reduces environmental pollution, but also improves the efficiency and quality of steelmaking.

[0041] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for converter steelmaking using a dephosphorization and low-slag agent, characterized in that: After the lower gun is ignited normally, the materials are added in two batches. The first batch of materials is added within 1.5 minutes. The first batch of materials includes lime, light-burned dolomite, gravel, dephosphorization and slag-reducing agent and returned ore. After the first batch of materials is added and the initial slag is formed, the second batch of materials is added. The second batch of materials is added within 7 minutes. The second batch of materials includes gravel and raw dolomite.

2. The method according to claim 1, characterized in that The chemical composition of the dephosphorization and slag-reducing agent includes, by weight percentage, Fe2O3 56.7%, CaO 6.19%, Al2O3 10.38%, SiO2 3.88%, MgO 2.56%, Na2O 1.77%, and the remainder includes one or more of Cu, Cr, As and unavoidable impurities.

3. The method according to claim 1, characterized in that: The first batch of materials contains 600-800kg of lime, 0-400kg of light-burned dolomite, 0-1000kg of gravel, 300-800kg of dephosphorization and 0-1000kg of returned ore.

4. The method according to claim 1, characterized in that: The second batch of materials contains 800-1500kg of gravel and 800-2000kg of raw dolomite.

5. The method according to claim 1, characterized in that: After the second batch of materials is added, if the slag is dry, add 200-300kg of dephosphorization and slag-reducing agent to adjust the slag.

6. The method according to claim 1, characterized in that: After the first batch of material is added, the gun position is controlled at 1.3-1.4m.

7. The method according to claim 1, characterized in that: At the end of smelting, the gun position will be ≤1m and the gun pressing time will be >40s.

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