Method for smelting low-manganese molten steel from low-silicon high-manganese molten iron through converter single-slag method

Abstract

The invention belongs to the technical field of metallurgy, and particularly relates to a method for smelting low-manganese molten steel from low-silicon high-manganese molten iron through a converter single-slag method, the single-slag method is adopted for smelting molten iron with the silicon content being smaller than or equal to 0.10% and the manganese content being 0.30-0.50%, operation is conducted on the molten iron with slag, the slag is molten iron slag and comprises 25%-35% of CaO, 30%-40% of SiO2, 5%-10% of MgO, 15%-25% of Al2O3 and the balance unavoidable impurities, the adding amount of the molten iron slag is 25-45 kg / t, and the converter single-slag method is adopted for smelting the molten iron with the slag. Bottom blowing is started in the whole smelting process, a variable-pressure and variable-lance-position oxygen blowing method is adopted, and the feeding system in the smelting process is synchronously controlled. Finally, molten steel with the manganese content smaller than or equal to 0.05% is produced through the converter single-slag method.

Description

Technical Field

[0001] The invention belongs to the technical field of converter steelmaking, in particular to a method for smelting low-manganese molten steel using a single-slag converter method with low-silicon and high-manganese molten iron. Background Art

[0002] Industrial pure iron is a metal with a very low carbon content. Its chemical composition is primarily iron. The lower the content of other alloying elements, the better. Manganese content in steel, in particular, affects performance indicators such as electrical conductivity. Generally, the manganese content is required to be ≤0.05%. Manganese in molten steel is primarily removed in the converter. The demanganization reaction in the converter is primarily [Mn] + FeO = Fe + (MnO) + Q. This reaction is exothermic, and low temperatures favor demanganization. MnO is an alkaline oxide, so increasing the acidity in the slag reduces its activity and promotes the demanganization reaction. Increasing the slag volume increases the manganese capacity of the slag, thereby increasing the amount of manganese removed. This analysis indicates that lowering the melt temperature, adding some acidic substances, and increasing the slag volume are beneficial for promoting the demanganization reaction.

[0003] To ensure that the manganese content of molten steel meets the standard, converters generally use a double-slag process. For example, Chinese patent CN110453032 A provides a method for smelting ultra-low manganese steel using high-manganese molten iron. The double-slag process removes most of the manganese in the molten iron during the converter process. Further manganese removal is achieved through low-temperature tapping from the converter and deep manganese removal through LF refining. This achieves a stable manganese content in the molten steel below 0.02% while maintaining a manganese content above 0.40% in the molten iron. However, the double-slag process requires slag removal mid-process, which results in extended production cycles and difficulty matching production rhythms, making it difficult to adapt to the needs of high-efficiency continuous production. The single-slag method, on the other hand, makes it difficult to achieve stable manganese removal in molten steel.

[0004] The single-slag method, in particular, presents greater technical challenges for the smelting of low-silicon, high-manganese hot metal. The primary source of acidic substances in converter slag is the oxidation of silicon in the molten iron. Low-silicon, high-manganese hot metal has a low silicon content, resulting in a low calorific value, making it difficult to quickly melt the added alkaline slagging agents (lime and light-burned dolomite). Furthermore, the low silicon content of the hot metal reduces the SiO2 content in the slag, preventing the addition of large amounts of slagging agents (because the added slagging agents lack acidic substances to bind and cannot melt). This makes slagging difficult, and the small amount of converter slag makes demanganese removal from low-silicon, high-manganese hot metal challenging.

[0005] Therefore, how to achieve efficient manganese removal from low-silicon, high-manganese hot metal under single-slag smelting conditions while maintaining a stable production rhythm has become a key technical challenge that needs to be solved urgently. To address this problem, the present invention has developed a method for smelting low-manganese molten steel from low-silicon, high-manganese hot metal using a single-slag converter process, which can ensure that the manganese content at the converter end point is stably controlled within 0.05%. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for smelting low-manganese molten steel by a single-slag method in a low-silicon high-manganese molten iron converter, thereby realizing the production of low-manganese molten steel by the single-slag method. The technical solution adopted is: A method for smelting low-manganese molten steel using a single-slag converter method with low-silicon high-manganese molten iron adopts an empty furnace smelting method, comprising the following steps: adding scrap steel, molten iron and molten iron slag → blowing oxygen into the converter, making slag → pouring slag → tapping steel.

[0007] Specifically, the addition of scrap steel, molten iron and molten iron slag: the converter scrap steel ratio is controlled to be 10-20%, the silicon content of the molten iron is ≤0.10%, the manganese content of the molten iron is 0.30-0.50%, the amount of molten iron slag added is controlled to be 25-45 kg / t, and the basicity of the molten iron slag is controlled to be 0.7-1.0; It also includes the steps of oxygen blowing, slag making, slag pouring and steel tapping in the converter, while controlling the feeding system, oxygen supply system and bottom blowing system of the smelting process to remove manganese.

[0008] Specifically, the temperature of the molten iron is 1250-1450°C.

[0009] Specifically, the oxygen supply system for the converter oxygen blowing and slagging is: oxygen blowing starts for 4 minutes, and the oxygen supply intensity is controlled at 5.0~6.0Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.0~4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.0~4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0010] Specifically, the basicity of the converter terminal slag is controlled at 2.0-2.5, the MgO content of the slag is controlled at 10.0-15.0%, and the FeO content of the slag is controlled at 15.0-25.0%.

[0011] Specifically, the feeding system for oxygen blowing and slag making in the converter is as follows: from the start of oxygen blowing to 4 minutes, 8-20 kg / t of light-burned dolomite, 0-10 kg / t of lime, and 15-30 kg / t of ore are added at one time; and 10-20 kg / t of lime, 5-10 kg / t of light-burned dolomite, and 10-20 kg / t of ore are added in small amounts and multiple batches during the 4-9 minutes of oxygen blowing.

[0012] Specifically, the bottom blowing system of the converter oxygen blowing and slagging includes: the bottom blowing intensity is controlled at 0.05~0.10Nm from the start of oxygen blowing to 4min of oxygen blowing. 3 / t / min; blow oxygen for 4 minutes until the end of blowing, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0013] Furthermore, the mass percentages of the components of the molten iron slag are: CaO: 25-35%, SiO2: 30-40%, MgO: 5-10%, Al2O3: 15-25%, and the others are inevitable impurities.

[0014] Furthermore, in the method for smelting low-manganese molten steel using a single-slag converter method with low-silicon and high-manganese molten iron, the converter endpoint temperature is controlled at 1560-1620°C, the endpoint molten steel carbon content is ≤0.05%, the endpoint molten steel oxygen content is 0.08-0.12%, the molten steel manganese content is ≤0.05%, and the demanganese rate reaches more than 90%.

[0015] The calculation formula of the demanganese rate is (molten iron volume*molten iron manganese content+scrap steel volume*scrap steel manganese content-molten steel volume*molten steel manganese content) / (molten iron volume*molten iron manganese content+scrap steel volume*scrap steel manganese content)*100%.

[0016] The present invention realizes the single slag smelting of low-manganese molten steel, and its specific technical advantages are: (1) Hot metal slag is a solid waste from ironmaking and is difficult to utilize effectively. However, the present invention utilizes the large amount of acidic substances such as SiO2 and Al2O3 contained in hot metal slag and applies it to converter smelting to help remove manganese. Hot metal slag is hot molten slag that can promote converter slagging and increase the slag volume. The acidic substances provided can not only reduce the activity of MnO in the slag to promote the demanganese reaction, but also promote the addition and melting of alkaline slag-forming agents (lime and light-burned dolomite), further increase the slag volume, and promote demanganese. It can perfectly solve the problems of converter slagging difficulties caused by low silicon content in hot metal, high basicity of the final slag, and small slag volume.

[0017] (2) The present invention uses ore in the early stage of converter smelting. In the rapid demanganeseization period, the following means are mainly adopted to achieve efficient demanganeseization: ① providing a large amount of oxygen source, ore and a large oxygen blowing flow rate; ② increasing the kinetic conditions, combining large flow top blowing and bottom blowing to improve the kinetic conditions; ③ introducing low-alkalinity acidic molten iron slag to provide a large amount of SiO2 and Al2O3 in the molten pool to promote the demanganeseization reaction.

[0018] (3) The present invention adopts empty furnace smelting, and the slag in the slag contains a high MnO content, which will affect the overall manganese removal effect. Using an empty furnace without slag smelting can reduce the MnO content in the total slag and improve the manganese removal ability of the slag. DETAILED DESCRIPTION Example 1

[0019] 130t converter smelting. Using an empty furnace, the process includes the following steps: adding scrap steel, molten iron, and molten iron slag → oxygen blowing and slag making → slag pouring → tapping.

[0020] Add scrap steel, molten iron and molten iron slag: molten iron volume 115t, molten iron slag volume 2900kg, molten iron slag composition is CaO: 26.7%, SiO2: 38.1%, MgO: 6.8%, Al2O3: 23.8%, others are unavoidable impurities, molten iron slag alkalinity is 0.70, molten iron temperature 1385℃, molten iron silicon content: 0.05%, molten iron phosphorus content: 0.12%, molten iron manganese content: 0.32%, scrap steel volume 25t, scrap steel manganese content: 0.28%.

[0021] The oxygen supply system for converter oxygen blowing and slagging is: from the start of blowing to 4 minutes of oxygen blowing, the oxygen supply intensity is controlled at 5.5Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.2Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0022] The oxygen blowing and slag-forming charging system for the converter is as follows: 1500 kg of light-burned dolomite and 3100 kg of ore are added in one batch during oxygen blowing for 0-4 minutes; 1900 kg of lime, 1300 kg of light-burned dolomite, and 2100 kg of ore are added in small batches during oxygen blowing for 4-9 minutes. The total converter load is 1900 kg of lime, 2800 kg of light-burned dolomite, and 5200 kg of ore. The final converter slag basicity, MgO content, and FeO content are controlled at 2.3, 12.2%, and 19.8%.

[0023] The bottom blowing system for converter oxygen blowing and slagging is as follows: the bottom blowing intensity is controlled at 0.08Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4min~lift the gun, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0024] The smelting process described above yielded 130 tons of molten steel in the converter at a temperature of 1585°C, with a final carbon content of 0.032%, a final phosphorus content of 0.015%, a final manganese content of 0.032%, a molten steel oxygen content of 0.092%, and a final slag volume of 13.3 tons. The demanganese content was 90.5%. Example 2

[0025] 130t converter smelting. Using an empty furnace, the process includes the following steps: adding scrap steel, molten iron, and molten iron slag → oxygen blowing and slag making → slag pouring → tapping.

[0026] Add scrap steel, molten iron and molten iron slag: molten iron volume 115t, molten iron slag volume 3800kg, molten iron slag composition is CaO: 28.9%, SiO2: 35.2%, MgO: 6.9%, Al2O3: 20.5%, others are inevitable impurities, molten iron slag alkalinity is 0.82, molten iron temperature 1392℃, molten iron silicon 0.08%, molten iron phosphorus: 0.126%, molten iron manganese: 0.41%, scrap steel volume 25t, scrap steel manganese content 0.30%.

[0027] The oxygen supply system for converter oxygen blowing and slagging is: from the start of blowing to 4 minutes of oxygen blowing, the oxygen supply intensity is controlled at 5.5Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.2Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0028] The oxygen blowing and slag-forming charging system for the converter is as follows: 1800 kg of light-burned dolomite and 3300 kg of ore are added in one go during oxygen blowing for 0-4 minutes; 2100 kg of lime, 1300 kg of light-burned dolomite, and 2300 kg of ore are added in small batches during oxygen blowing for 4-9 minutes. The total converter load is 2100 kg of lime, 3100 kg of light-burned dolomite, and 5600 kg of ore. The final converter slag basicity, MgO content, and FeO content are controlled at 2.2, 13.2%, and 21.3%.

[0029] Bottom blowing system for converter oxygen blowing and slagging: The bottom blowing intensity is controlled at 0.08Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4min~lift the gun, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0030] Using the above method, the final converter molten steel volume was 129.6 tons, the temperature was 1596°C, the final carbon content was 0.026%, the final phosphorus content was 0.013%, the final manganese content was 0.028%, the molten steel oxygen content was 0.103%, and the final slag volume was 15.1 tons. The demanganese rate was 93.4%. Example 3

[0031] 130t converter smelting. Using an empty furnace, the process includes the following steps: adding scrap steel, molten iron, and molten iron slag → oxygen blowing and slag making → slag pouring → tapping.

[0032] Add scrap steel, molten iron and molten iron slag: molten iron volume 115t, molten iron slag volume 4600kg, molten iron slag composition is CaO: 32.3%, SiO2: 33.8%, MgO: 5.9%, Al2O3: 21.6%, others are unavoidable impurities, molten iron slag alkalinity is 0.96, molten iron temperature 1365℃, molten iron silicon 0.10%, molten iron phosphorus: 0.123%, molten iron manganese: 0.48%, scrap steel volume 25t, scrap steel manganese content 0.38%.

[0033] The oxygen supply system for converter oxygen blowing and slagging is: from the start of blowing to 4 minutes of oxygen blowing, the oxygen supply intensity is controlled at 5.5Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.2Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0034] The oxygen blowing and slagging feeding schedule for the converter is as follows: During oxygen blowing for 0-4 minutes, 2100 kg of light-burned dolomite, 600 kg of lime, and 2800 kg of ore are added all at once. During oxygen blowing for 4-9 minutes, 1900 kg of lime, 1300 kg of light-burned dolomite, and 2500 kg of ore are added in small batches. The total converter load is 2500 kg of lime, 3400 kg of light-burned dolomite, and 5300 kg of ore. The final converter slag basicity, MgO content, and FeO content are controlled at 2.32, 12.7%, and 23.6%.

[0035] Bottom blowing system for converter oxygen blowing and slagging: The bottom blowing intensity is controlled at 0.08Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4min~lift the gun, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0036] The above-mentioned smelting method produced 129.3 tons of molten steel in the converter at a temperature of 1582°C, with a final carbon content of 0.033%, a final phosphorus content of 0.014%, a manganese content of 0.041%, an oxygen content of 0.098%, and a final slag volume of 15.9 tons. The demanganese efficiency was 91.8%.

[0037] Comparative Example 1 (Compared with Example 1, the molten iron was operated without molten iron slag. To ensure the slag basicity, the amount of slag added was small, and the final slag amount was insufficient, resulting in a high final manganese content)

[0038] 130t converter smelting. Using an empty furnace, the process includes the following steps: adding scrap steel, molten iron, and molten iron slag → oxygen blowing and slag making → slag pouring → tapping.

[0039] Add scrap steel, molten iron and molten iron slag: molten iron volume 115t, molten iron slag volume 0kg, molten iron temperature 1386℃, molten iron silicon 0.06%, molten iron phosphorus: 0.123%, molten iron manganese: 0.322%, scrap steel volume 25t, scrap steel manganese content 0.275%.

[0040] The oxygen supply system for converter oxygen blowing and slagging is: from the start of blowing to 4 minutes of oxygen blowing, the oxygen supply intensity is controlled at 5.5Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.2Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0041] The feeding system for oxygen blowing and slag formation in the converter is as follows: During oxygen blowing for 0-4 minutes, 1200 kg of light-burned dolomite and 3100 kg of ore are added all at once. During oxygen blowing for 4-9 minutes, 1200 kg of lime, 300 kg of light-burned dolomite, and 2100 kg of ore are added in small batches. The total amount of lime added is 1200 kg, the total amount of light-burned dolomite added is 1500 kg, and the total amount of ore added is 5200 kg. The basicity of the final converter slag is controlled at 2.31, the MgO content is controlled at 16.2%, and the FeO content is controlled at 20.1%.

[0042] Bottom blowing system for converter oxygen blowing and slagging: The bottom blowing intensity is controlled at 0.08Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4min~lift the gun, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0043] Using the above method, the final converter molten steel volume was 130.2 tons, the temperature was 1582°C, the final carbon content was 0.030%, the final phosphorus content was 0.026%, the final manganese content was 0.105%, the molten steel oxygen content was 0.095%, and the final slag volume was 7.8 tons. The demanganese content was 68.9%.

[0044] Comparative Example 2 (Compared with Example 1, the molten iron was operated without molten iron slag, and the smelting was not done in an empty furnace, ensuring a consistent slag amount, but the end point basicity was higher and the end point manganese content was higher)

[0045] 130t converter smelting. Non-empty furnace smelting, the slag is removed after the previous furnace smelting, and the empty furnace slag is retained. The slag volume is 6.9t and the slag basicity is 3.1; The process includes the following steps: adding scrap steel, molten iron and molten iron slag → blowing oxygen into the converter, making slag → pouring slag → tapping steel.

[0046] Add scrap steel, molten iron and molten iron slag: molten iron volume 115t, molten iron slag volume 0kg, molten iron temperature 1382℃, molten iron silicon 0.052%, molten iron phosphorus: 0.122%, molten iron manganese: 0.318%; scrap steel volume 25t, scrap steel manganese content 0.273%.

[0047] The oxygen supply system for converter oxygen blowing and slagging is: from the start of blowing to 4 minutes of oxygen blowing, the oxygen supply intensity is controlled at 5.5Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; oxygen blowing is 4~9min, and the oxygen supply intensity is controlled at 4.2Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; ​​oxygen is blown for 9 minutes until the end of blowing, and the oxygen supply intensity is controlled at 4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

[0048] The oxygen blowing and slag-forming charging system for the converter is as follows: 1500 kg of light-burned dolomite and 3100 kg of ore are added in one go during oxygen blowing for 0-4 minutes; 1900 kg of lime, 1300 kg of light-burned dolomite, and 2100 kg of ore are added in small batches during oxygen blowing for 4-9 minutes. The total converter load is 1900 kg of lime, 2800 kg of light-burned dolomite, and 5200 kg of ore. The final converter slag basicity, MgO content, and FeO content are controlled at 4.56, 14.2%, and 19.8%.

[0049] Bottom blowing system for converter oxygen blowing and slagging: The bottom blowing intensity is controlled at 0.08Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4min~lift the gun, and control the bottom blowing intensity at 0.01Nm 3 / t / min (anti-blocking mode).

[0050] Using the above method, the final converter molten steel volume was 129.8 tons, the temperature was 1575°C, the final carbon content was 0.030%, the final phosphorus content was 0.018%, the final manganese content was 0.082%, the molten steel oxygen content was 0.093%, and the final slag volume was 13.4 tons. The demanganese rate was 75.5%.

[0051] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for smelting low-manganese molten steel using a low-silicon, high-manganese molten iron converter single-slag process, characterized in that: Empty furnace smelting is adopted, which includes the following steps: adding scrap steel, adding molten iron and molten iron slag → blowing oxygen into the converter, making slag → pouring slag → tapping; The silicon content of the molten iron is ≤0.10%.

2. The method for smelting low-manganese molten steel using a single-slag process using low-silicon high-manganese molten iron in a converter according to claim 1, wherein: The molten iron slag is composed of the following components in mass percentage: CaO: 25-35%, SiO2: 30-40%, MgO: 5-10%, Al2O3: 15-25%, and the rest are inevitable impurities; the basicity of the molten iron slag is 0.7-1.

0.

3. The method for smelting low-manganese molten steel using a single-slag process using low-silicon high-manganese molten iron in a converter according to claim 1, characterized in that: The manganese content of the molten iron is 0.30-0.50%; the converter scrap ratio is 10-20%.

4. The method for smelting low-manganese molten steel using a single-slag process using low-silicon high-manganese molten iron in a converter according to claim 1, wherein: The amount of molten iron slag added is 25-45 kg / t.

5. The method for smelting low-manganese molten steel using a single-slag process using low-silicon high-manganese molten iron in a converter according to claim 1, characterized in that: The oxygen supply system for the converter oxygen blowing and slagging is as follows: Blowing starts ~ Blow oxygen for 4 minutes, and the oxygen supply intensity is controlled at 5.0~6.0Nm 3 / t / min, the oxygen lance position is controlled at 2.0~2.2m; Blow oxygen for 4~9 minutes, and control the oxygen supply intensity at 4.0~4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.7~1.9m; Blow oxygen for 9 minutes until the end of blowing, and control the oxygen supply intensity at 4.0~4.5Nm 3 / t / min, the oxygen lance position is controlled at 1.2~1.6m.

6. The method for smelting low-manganese molten steel using a single-slag converter process with low-silicon high-manganese molten iron according to claim 1, characterized in that: The feeding system of the converter oxygen blowing and slag making is as follows: Blow oxygen for 0-4 minutes, add 8-20 kg / t of light-burned dolomite, 0-10 kg / t of lime, and 15-30 kg / t of ore at one time; blow oxygen for 4-9 minutes using the principle of small amounts and multiple batches, add 10-20 kg / t of lime, 5-10 kg / t of light-burned dolomite, and 10-20 kg / t of ore.

7. The method for smelting low-manganese molten steel using a single-slag converter process with low-silicon high-manganese molten iron according to claim 1, characterized in that: The bottom blowing system of the converter oxygen blowing and slagging is: The bottom blowing intensity is controlled at 0.05~0.10Nm from the start of oxygen blowing to 4 minutes. 3 / t / min; Blow oxygen for 4 minutes until the gun is lifted, and the bottom blowing intensity is controlled at 0.01Nm 3 / t / min.

8. The method for smelting low-manganese molten steel using a converter single-slag process with low-silicon high-manganese molten iron according to claim 1, characterized in that: The temperature of the molten iron is 1250-1450°C.

9. The method for smelting low-manganese molten steel using a single-slag converter process with low-silicon high-manganese molten iron according to claim 1, characterized in that: The basicity of the converter final slag is controlled at 2.0~2.5, the MgO content of the slag is controlled at 10.0~15.0%, and the FeO content of the slag is controlled at 15.0~25.0%; the converter final temperature is controlled at 1560~1620℃.