阅读说明：本技术 一种渣铁替代全量废钢的转炉炼钢方法 (Converter steelmaking method by replacing full amount of scrap steel with iron slag ) 是由 邓南阳 潘军 夏能伟 于 2020-12-15 设计创作，主要内容包括：本发明公开一种渣铁替代全量废钢的转炉炼钢方法,包括以下步骤：转炉造渣主要原料分别为石灰、轻烧镁球和石灰石,上炉出钢完毕后,翻去一半炉渣,留渣量控制在35～45kg/t,然后进行溅渣固化并加以确认,铁水910-930kg/t,渣铁110-130kg/t,转炉冶炼采用“留1/2渣+双渣”和“高拉补吹”操作模式,石灰、轻烧镁球和石灰石加入总量分别按照40～50kg/([Si]％×100)、6.0～8kg/t和5～7kg/t控制,冶炼结束,钢水成分和温度符合工艺要求后,倾动转炉正常出钢,经脱氧合金化操作得到合格钢水。本发明采用“留1/2渣+双渣”操作法,可以最大限度地减少硫、磷带入量,降低石灰用量,避免大渣量操作引发喷溅和冶炼后钢水硫、磷成分波动,实现渣铁大量有效回收再利用。(The invention discloses a converter steelmaking method by replacing full scrap steel with iron slag, which comprises the following steps: the converter slagging main raw materials are respectively lime, light-burned magnesium balls and limestone, after the steel tapping is finished, half of the slag is turned over, the slag amount is controlled to be 35-45 kg/t, then slag splashing solidification is carried out, the confirmation is carried out, 930kg/t of molten iron 910 and 130kg/t of slag iron 110 are adopted for converter smelting, the operation modes of 1/2 slag retention, double slag retention and high-tension complementary blowing are adopted for converter smelting, the total adding amount of the lime, the light-burned magnesium balls and the limestone is respectively controlled according to 40-50 kg/([ Si ]% × 100), 6.0-8 kg/t and 5-7 kg/t, after the smelting is finished, the converter is tilted to normally tap steel after the molten steel components and the temperature meet the process requirements, and qualified molten steel is obtained through deoxidation alloying operation. The invention adopts an operation method of 'leaving 1/2 slag and double slag', can reduce the carrying amount of sulfur and phosphorus to the utmost extent, reduce the lime using amount, avoid splashing caused by large slag amount operation and fluctuation of sulfur and phosphorus components of molten steel after smelting, and realize effective recycling of a large amount of slag iron.)

1. A converter steelmaking method for replacing full scrap steel with iron slag is characterized by comprising the following steps:

the method comprises the following steps: smelting conditions are as follows: smelting steel grades with the content of [ P ] and the content of [ S ] being less than or equal to 0.045%, wherein the content and the temperature of molten iron [ Si ] meet the conditions that [ Si ] percent x 100+ T is less than or equal to 1400, a smelting blowing oxygen lance is a 4-hole Laval nozzle, the oxygen supply intensity is 3.3-3.6 m3/(T & min), and the main materials for converter slagging are lime, light-burned magnesium balls and limestone respectively, wherein the technical indexes of the lime are as follows: w (CaO) is more than or equal to 85.00 percent, w (SiO2) is less than or equal to 3.50 percent, w (S) is less than or equal to 0.060 percent, activity degree is more than or equal to 250.0ml, and reduction is less than or equal to 10.0 percent; the technical indexes of the light-burned magnesium balls are as follows: w (MgO) is more than or equal to 60.00 percent, w (SiO2) is less than or equal to 7.50 percent, and water content is less than or equal to 2.0 percent; the technical indexes of limestone are as follows: w (CaO) is more than or equal to 53.00 percent, w (MgO) is less than or equal to 3.00 percent, w (SiO2) is less than or equal to 1.50 percent;

step two: slag remaining operation: after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 35-45 kg/t, and then carrying out slag splashing solidification and confirming;

step three: a loading system: the molten iron 910-;

step four: smelting operation: the converter smelting adopts an operation mode of '1/2 slag reserving + double slag' and 'high-tension complementary blowing', the adding total amount of lime, light-burned magnesium balls and limestone is controlled according to 40-50 kg/([ Si ]%. times.100), 6.0-8 kg/T and 5-7 kg/T respectively, the adding amount of sintering ore is controlled according to the heat balance requirement, and the reference adding total amount is controlled according to 2.0-2.5 kg/([ Si ]%. times.100 + T);

step five: tapping operation: after the smelting is finished, the components and the temperature of the molten steel meet the process requirements, the converter is tilted to normally tap steel, and qualified molten steel is obtained through deoxidation alloying operation.

2. The converter steelmaking method using iron slag to replace the total amount of scrap steel according to claim 1, wherein the four specific smelting operations are as follows:

s1, adopting a high lance position and a large oxygen pressure for ignition, wherein the lance position is 1800mm, the distance between a spray head of the oxygen lance and the liquid level is 1800mm, the oxygen pressure is 900kpa, the oxygen flow is 14500-15000 m3/h, the phenomena of large slag quantity and combustion robbery caused by unsmooth ignition are prevented, and the ignition time is 0.5 min;

s2, after ignition is normal, gradually reducing the lance position of the oxygen lance to 1200-1300 mm, gradually reducing the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, adjusting the oxygen pressure to 750kpa, adjusting the oxygen flow to 12500-13000 m3/h, adding 5-7 kg/t limestone when converting for 1min, and utilizing the thermal decomposition of the limestone to generate CO2 gas to ensure that the slag has foaming property and is beneficial to deslagging;

s3, continuing blowing for 2.0-2.5 min, lifting the gun, closing oxygen, rapidly switching to a 'nitrogen manual' mode, blowing nitrogen again with the gun at the flow rate of 15000-16000 m3/h, with the gun position of 4500-4800 mm and the distance between the oxygen lance nozzle and the liquid level of 4500-4800 mm, blowing the foaming slag with nitrogen to eliminate the foaming degree of the slag, facilitating the precipitation of metal particles in the slag, tilting the converter after blowing nitrogen for 0.5min, pouring 40-60% of slag with high sulfur and phosphorus enrichment, and pouring the slag for 1 min;

s4, after deslagging, blowing again, wherein the position of an oxygen lance is 1300-1400 mm, the distance between a spray head of the oxygen lance and the liquid level is 1300-1400 mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, when blowing is 1.5-2 min, lime and sinter are added into 2/3 of the total amount respectively, and light-burned magnesium balls are added at one time;

s5, after feeding, lowering the position of an oxygen lance to 1200-1300 mm, keeping the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, keeping the oxygen pressure at 700kpa, keeping the oxygen flow at 12000-12500 m3/h, completely adding the lime in the residual 1/3 total amount before the 8 th min of blowing, and completely adding the sintered ore in the residual 1/3 total amount before the 10 th min of blowing according to the heat balance requirement;

s6, when the blowing is continued to the 11 th min, because the carbon-oxygen reaction is weaker at the moment, the lance position is increased to 1400-1500 mm, and the distance between an oxygen lance nozzle and the liquid level is 1400-1500 mm, so that the slagging is promoted, and the slag is prevented from being dried back to phosphorus;

s7, when the blowing time is 12min, the position of an oxygen lance is reduced to 1000mm, the distance between a spray head of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is adjusted to 750kpa, the oxygen flow is 12500-13000 m3/h, the stirring of a molten pool is enhanced, the components and the temperature of molten steel are uniform, the lance pressing time is 0.75min, and the furnace is turned over, the temperature is measured and the samples are taken;

and S8, performing complementary blowing operation according to the composition and temperature of the poured molten steel, wherein the lance position of the oxygen lance is 1000mm, the distance between a lance nozzle of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, and the lance pressing time is 0.75min, and pouring the steel again to perform temperature measurement and sampling.

3. The converter steelmaking method using iron slag in place of the full amount of scrap as claimed in claim 2 in which said step four is exemplified by the converter floor height "± 0 mm".

Technical Field

The invention relates to the technical field of converter steelmaking technology, in particular to a converter steelmaking method by using slag iron to replace full scrap steel.

Background

The pretreatment desulfurization of the molten iron can stably provide low-sulfur molten iron with the sulfur content of less than 0.002 percent for the smelting production of the converter, and is a main technical means which is generally adopted by modern iron and steel enterprises and is used for improving the product quality and developing high value-added products. For the molten iron adopting the blowing desulfurization process, the phenomenon of splashing is easily caused due to the influence of comprehensive factors such as the capacity and clearance of a molten iron tank, the blowing rate of a desulfurizing agent, the insertion depth of a spray gun and the like. In addition, in the process of the ladle-to-ladle operation, if the opening of the torpedo ladle is irregular or the tapping speed is too high, the molten iron is easy to splash and spill. The slag iron is a product splashed in the molten iron spraying and ladle-to-ladle operation processes in the blowing desulfurization process, and 0.42-0.45 kg of slag iron can be generated in each ton of steel. As an important iron-containing resource, the iron in the slag iron has a mass fraction larger than that of the slag steel, has high hardness, is not easy to break, is directly damaged in the takeaway economy, and not only causes resource waste but also pollutes the environment by abandoning and discharging. Although the iron content of the slag iron is high (the TFe content is over 85 percent, and the metal iron content is over 70 percent), the molten steel components after the converter smelting, especially the sulfur content, fluctuate greatly due to high and unstable sulfur and phosphorus content of the slag iron, especially the sulfur content of the slag iron generated by splashing in the molten iron blowing process, and the molten steel components cannot be recycled well. In the prior art, after part of steel enterprises finely crush the desulfurized slag iron, the desulfurized slag iron with small granularity is added into an iron ladle, and the desulfurized slag iron is melted by using stirring power in the blast furnace tapping process, but the treatment capacity of the desulfurized slag iron of each ladle of iron is only about 1t, so that the popularization and the application of the desulfurized slag iron are limited; the method that the desulfurized slag iron is crushed, processed and screened is adopted by part of the steel enterprises, and the desulfurized slag iron is used as one part of the ore for manufacturing the sinter, so that the production flow is long, the processing difficulty is high, and the cost is high; and because the slag content of the desulfurized slag and the steel slag is large and generally accounts for about 40%, in order to ensure the dephosphorization effect during converter smelting, a large amount of lime is required to be added for dephosphorization, and in addition, the amount of slag brought by desulfurized slag iron and slag steel is large, so that the equipment is easy to damage, the smelting cost is increased, and the large effective recycling of the desulfurized slag and the steel slag is limited.

Chinese patent No. CN110241283A discloses a converter utilization method of desulfurized iron slag, which comprises the following steps: adding raw materials into a top-bottom combined blown converter, wherein the raw materials comprise coke, desulfurized iron slag and molten iron; blowing by a top-bottom combined blowing converter to enable the raw materials to form a molten state; pouring the formed molten semisteel into a ladle; performing KR desulfurization treatment on the semisteel; pouring the raw materials subjected to KR desulfurization into a top-bottom combined blown converter for conventional smelting. Chinese patent No. CN110396566A also discloses a method for recycling desulfurized iron slag in a converter, which adds desulfurized iron slag into the converter and adds a part of molten iron for oxygen blowing and converting, thus promoting the melting of desulfurized iron slag and forming semisteel after the desulfurized iron slag is melted. Pouring the semisteel into a ladle for desulfurization pretreatment. Through the mixing of the semisteel and the molten iron, the components of the mixed semisteel are ensured to be closer to the components of the molten iron, and the components of the molten iron after the pretreatment desulfurization are close to the components of the conventional molten iron, so that the molten iron can be directly added into a converter for utilization. The two methods play a certain positive role in the aspect of recycling of the desulfurized iron slag, but the two methods carry out oxygen blowing operation in a converter to melt raw materials to form semisteel, then pour the semisteel into a ladle, carry out normal smelting after desulfurization pretreatment, have relatively complex treatment flow, prolong production period, increase the problems of energy and power consumption and operation labor intensity, limit the popularization and application of the method, and provide a converter steelmaking method for replacing the full amount of scrap steel by the iron slag aiming at the situation.

Disclosure of Invention

The invention aims to provide a converter steelmaking method for replacing full scrap steel with iron slag, which adopts the iron slag with relatively high sulfur content generated by splashing in the molten iron desulphurization and injection process and the iron slag with relatively low sulfur content generated by splashing in the ladle transfer operation process, mixing the materials according to the weight ratio of 1:2 to be used as a coolant to replace the whole amount of scrap steel, adopting an operation method of 'leaving 1/2 slag and double slag' for converter smelting, the method can reduce the brought amount of sulfur and phosphorus to the maximum extent, reduce the using amount of lime, avoid splashing caused by large-slag-amount operation and fluctuation of sulfur and phosphorus components of molten steel after smelting, realize effective recycling of a large amount of slag iron, solve the technical problem that the slag iron cannot be effectively recycled in a large amount in the prior art, reduce the production cost of converter steelmaking, reduce environmental pollution caused by waste discharge of the slag iron, and finally achieve the purposes of effective recycling of the slag iron in a large amount, energy conservation and consumption reduction.

The purpose of the invention can be realized by the following technical scheme:

a converter steelmaking method for replacing full scrap steel with iron slag comprises the following steps:

the method comprises the following steps: smelting conditions are as follows: smelting steel grades with the content of [ P ] and the content of [ S ] being less than or equal to 0.045%, wherein the content and the temperature of molten iron [ Si ] meet the conditions that [ Si ] percent x 100+ T is less than or equal to 1400, a smelting blowing oxygen lance is a 4-hole Laval nozzle, the oxygen supply intensity is 3.3-3.6 m3/(T & min), and the main materials for converter slagging are lime, light-burned magnesium balls and limestone respectively, wherein the technical indexes of the lime are as follows: w (CaO) is more than or equal to 85.00 percent, w (SiO2) is less than or equal to 3.50 percent, w (S) is less than or equal to 0.060 percent, activity degree is more than or equal to 250.0ml, and reduction is less than or equal to 10.0 percent; the technical indexes of the light-burned magnesium balls are as follows: w (MgO) is more than or equal to 60.00 percent, w (SiO2) is less than or equal to 7.50 percent, and water content is less than or equal to 2.0 percent; the technical indexes of limestone are as follows: w (CaO) is more than or equal to 53.00 percent, w (MgO) is less than or equal to 3.00 percent, w (SiO2) is less than or equal to 1.50 percent;

step two: slag remaining operation: after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 35-45 kg/t, and then carrying out slag splashing solidification and confirming;

step three: a loading system: the molten iron 910-;

step four: smelting operation: the converter smelting adopts an operation mode of '1/2 slag reserving + double slag' and 'high-tension complementary blowing', the adding total amount of lime, light-burned magnesium balls and limestone is controlled according to 40-50 kg/([ Si ]%. times.100), 6.0-8 kg/T and 5-7 kg/T respectively, the adding amount of sintering ore is controlled according to the heat balance requirement, and the reference adding total amount is controlled according to 2.0-2.5 kg/([ Si ]%. times.100 + T);

step five: tapping operation: after the smelting is finished, the components and the temperature of the molten steel meet the process requirements, the converter is tilted to normally tap steel, and qualified molten steel is obtained through deoxidation alloying operation.

Further, the fourth specific smelting operation is as follows:

s1, adopting a high lance position and a large oxygen pressure for ignition, wherein the lance position is 1800mm, the distance between a spray head of the oxygen lance and the liquid level is 1800mm, the oxygen pressure is 900kpa, the oxygen flow is 14500-15000 m3/h, the phenomena of large slag quantity and combustion robbery caused by unsmooth ignition are prevented, and the ignition time is 0.5 min;

s2, after ignition is normal, gradually reducing the lance position of the oxygen lance to 1200-1300 mm, gradually reducing the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, adjusting the oxygen pressure to 750kpa, adjusting the oxygen flow to 12500-13000 m3/h, adding 5-7 kg/t limestone when converting for 1min, and utilizing the thermal decomposition of the limestone to generate CO2 gas to ensure that the slag has foaming property and is beneficial to deslagging;

s3, continuing blowing for 2.0-2.5 min, lifting the gun, closing oxygen, rapidly switching to a 'nitrogen manual' mode, blowing nitrogen again with the gun at the flow rate of 15000-16000 m3/h, with the gun position of 4500-4800 mm and the distance between the oxygen lance nozzle and the liquid level of 4500-4800 mm, blowing the foaming slag with nitrogen to eliminate the foaming degree of the slag, facilitating the precipitation of metal particles in the slag, tilting the converter after blowing nitrogen for 0.5min, pouring 40-60% of slag with high sulfur and phosphorus enrichment, and pouring the slag for 1 min;

s4, after deslagging, blowing again, wherein the position of an oxygen lance is 1300-1400 mm, the distance between a spray head of the oxygen lance and the liquid level is 1300-1400 mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, when blowing is 1.5-2 min, lime and sinter are added into 2/3 of the total amount respectively, and light-burned magnesium balls are added at one time;

s5, after feeding, lowering the position of an oxygen lance to 1200-1300 mm, keeping the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, keeping the oxygen pressure at 700kpa, keeping the oxygen flow at 12000-12500 m3/h, completely adding the lime in the residual 1/3 total amount before the 8 th min of blowing, and completely adding the sintered ore in the residual 1/3 total amount before the 10 th min of blowing according to the heat balance requirement;

s6, when the blowing is continued to the 11 th min, because the carbon-oxygen reaction is weaker at the moment, the lance position is increased to 1400-1500 mm, and the distance between an oxygen lance nozzle and the liquid level is 1400-1500 mm, so that the slagging is promoted, and the slag is prevented from being dried back to phosphorus;

s7, when the blowing time is 12min, the position of an oxygen lance is reduced to 1000mm, the distance between a spray head of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is adjusted to 750kpa, the oxygen flow is 12500-13000 m3/h, the stirring of a molten pool is enhanced, the components and the temperature of molten steel are uniform, the lance pressing time is 0.75min, and the furnace is turned over, the temperature is measured and the samples are taken;

and S8, performing complementary blowing operation according to the composition and temperature of the poured molten steel, wherein the lance position of the oxygen lance is 1000mm, the distance between a lance nozzle of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, and the lance pressing time is 0.75min, and pouring the steel again to perform temperature measurement and sampling.

Further, the fourth step is to take the converter bottom height of plus or minus 0mm as an example.

The invention has the beneficial effects that:

1. according to the invention, the slag iron with relatively high sulfur content generated by splashing in the molten iron desulphurization and injection process and the slag iron with relatively low sulfur content generated by splashing in the ladle-to-ladle operation process are mixed according to the weight ratio of 1:2 to be used as a coolant to replace the whole amount of scrap steel, and the converter smelting adopts an operation method of 'leaving 1/2 slag and double slag', so that the carrying amount of sulfur and phosphorus can be reduced to the maximum extent, the lime consumption is reduced, the splashing caused by large-slag operation and the fluctuation of sulfur and phosphorus components of molten steel after smelting are avoided, and the slag iron is effectively recycled and reused in large quantities;

2. the invention solves the technical problem that the slag iron can not be effectively recycled in large quantity in the prior art, reduces the production cost of converter steelmaking, reduces the environmental pollution caused by the waste discharge of the slag iron, and finally achieves the aims of effectively recycling the slag iron in large quantity, saving energy and reducing consumption;

3. the method can realize effective recycling of a large amount of iron slag, almost all the iron slag generated in the production process can be fed back into the furnace, and the problems of occupied space and environmental pollution caused by waste discharge can be avoided;

4. the method of the invention reasonably matches the slag iron with different sulfur content, and the converter blowing adopts the operation mode of 'leaving 1/2 slag + double slag', thereby reducing the carrying amount of sulfur and phosphorus in the raw materials entering the converter to the utmost extent, stabilizing the sulfur and phosphorus components of the molten steel and improving the quality of the product.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a flow chart of the operation of the converter steelmaking process using iron slag in place of the total scrap steel of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A converter steelmaking method using slag iron to replace the total amount of scrap steel, as shown in figure 1, comprising the following steps:

the method comprises the following steps: smelting conditions are as follows: smelting steel grades with the content of [ P ] and the content of [ S ] being less than or equal to 0.045%, wherein the content and the temperature of molten iron [ Si ] meet the conditions that [ Si ] percent x 100+ T is less than or equal to 1400, a smelting blowing oxygen lance is a 4-hole Laval nozzle, the oxygen supply intensity is 3.3-3.6 m3/(T & min), and the main materials for converter slagging are lime, light-burned magnesium balls and limestone respectively, wherein the technical indexes of the lime are as follows: w (CaO) is more than or equal to 85.00 percent, w (SiO2) is less than or equal to 3.50 percent, w (S) is less than or equal to 0.060 percent, activity degree is more than or equal to 250.0ml, and reduction is less than or equal to 10.0 percent; the technical indexes of the light-burned magnesium balls are as follows: w (MgO) is more than or equal to 60.00 percent, w (SiO2) is less than or equal to 7.50 percent, and water content is less than or equal to 2.0 percent; the technical indexes of limestone are as follows: w (CaO) is more than or equal to 53.00 percent, w (MgO) is less than or equal to 3.00 percent, w (SiO2) is less than or equal to 1.50 percent;

step two: slag remaining operation: after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 35-45 kg/t, and then carrying out slag splashing solidification and confirming;

step three: a loading system: the molten iron 910-;

step four: smelting operation: the converter smelting adopts an operation mode of '1/2 slag reserving + double slag' and 'high-tension complementary blowing', the adding total amount of lime, light-burned magnesium balls and limestone is controlled according to 40-50 kg/([ Si ]%. times.100), 6.0-8 kg/T and 5-7 kg/T respectively, the adding amount of sintering ore is controlled according to the heat balance requirement, and the reference adding total amount is controlled according to 2.0-2.5 kg/([ Si ]%. times.100 + T);

step five: tapping operation: after the smelting is finished, the components and the temperature of the molten steel meet the process requirements, the converter is tilted to normally tap steel, and qualified molten steel is obtained through deoxidation alloying operation.

Taking the converter bottom height of +/-0 mm as an example, the smelting operation is as follows:

s1, adopting a high lance position and a large oxygen pressure for ignition, wherein the lance position is 1800mm, the distance between a spray head of the oxygen lance and the liquid level is 1800mm, the oxygen pressure is 900kpa, the oxygen flow is 14500-15000 m3/h, the phenomena of large slag quantity and combustion robbery caused by unsmooth ignition are prevented, and the ignition time is 0.5 min;

s2, after ignition is normal, gradually reducing the position of an oxygen lance to 1200-1300 mm, gradually reducing the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, adjusting the oxygen pressure to 750kpa, adjusting the oxygen flow to 12500-13000 m3/h, adding 5-7 kg/t limestone when blowing for 1min, and utilizing the limestone to generate CO2 gas through thermal decomposition to enable the slag to have certain foamability and be beneficial to deslagging;

s3, continuing blowing for 2.0-2.5 min, lifting the gun, closing oxygen, rapidly switching to a 'nitrogen manual' mode, blowing nitrogen again with the gun at the flow rate of 15000-16000 m3/h, with the gun position of 4500-4800 mm and the distance between the oxygen lance nozzle and the liquid level of 4500-4800 mm, blowing the foaming slag with nitrogen to eliminate the foaming degree of the slag, facilitating the precipitation of metal particles in the slag, tilting the converter after blowing nitrogen for 0.5min, pouring 40-60% of slag with high sulfur and phosphorus enrichment, and pouring the slag for 1 min;

s4, after deslagging, blowing again, wherein the position of an oxygen lance is 1300-1400 mm, the distance between a spray head of the oxygen lance and the liquid level is 1300-1400 mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, when blowing is 1.5-2 min, lime and sinter are added into 2/3 of the total amount respectively, and light-burned magnesium balls are added at one time;

s5, after feeding, lowering the position of an oxygen lance to 1200-1300 mm, keeping the distance between a spray head of the oxygen lance and the liquid level to 1200-1300 mm, keeping the oxygen pressure at 700kpa, keeping the oxygen flow at 12000-12500 m3/h, completely adding the lime in the residual 1/3 total amount before the 8 th min of blowing, and completely adding the sintered ore in the residual 1/3 total amount before the 10 th min of blowing according to the heat balance requirement;

s6, when the blowing is continued to the 11 th min, because the carbon-oxygen reaction is weaker at the moment, properly raising the lance position to 1400-1500 mm, and enabling the distance between an oxygen lance nozzle and the liquid level to be 1400-1500 mm, so that slagging is promoted, and slag is prevented from being dried back to phosphorus;

s7, when the blowing time is 12min, the position of an oxygen lance is reduced to 1000mm, the distance between a spray head of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is adjusted to 750kpa, the oxygen flow is 12500-13000 m3/h, the stirring of a molten pool is enhanced, the components and the temperature of molten steel are uniform, the lance pressing time is 0.75min, and the furnace is turned over, the temperature is measured and the samples are taken;

and S8, performing complementary blowing operation according to the composition and temperature of the poured molten steel, wherein the lance position of the oxygen lance is 1000mm, the distance between a lance nozzle of the oxygen lance and the liquid level is 1000mm, the oxygen pressure is 750kpa, the oxygen flow is 12500-13000 m3/h, and the lance pressing time is 0.75min, and pouring the steel again to perform temperature measurement and sampling.

Example 1

Smelting Q235B steel grade, wherein the requirements of the steel grade [ P ] and [ S ] are less than or equal to 0.035%, the content of molten iron [ Si ] is 0.26%, the temperature of the molten iron is 1346 ℃, and the height of the converter bottom is +/-0 mm;

after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 2.7t, and then carrying out slag splashing solidification and confirming;

63.5t of molten iron and 8.2t of slag iron are filled, and the converter is shaken to the zero position;

the set oxygen pressure is 900kpa, and the oxygen flow is 14800m³The oxygen pressure is adjusted to 750kpa and the oxygen flow is 12800m after the ignition at the gun position of 1800mm and the oxygen blowing for 30s³The oxygen lance position is lowered to 1200mm, oxygen is blown for 1min, 400kg of limestone is added, oxygen is blown for 1min continuously, the lance is lifted and oxygen is shut off; switching the operation of the oxygen lance into 'nitrogen manual operation', lowering the oxygen lance to 4600mm, starting nitrogen purging for 28s, lifting the lance, closing nitrogen, tilting the converter, pouring 50% of slag, and pouring the slag for 1 min;

and after the slag dumping is finished, the converter is rocked to the zero position. Set oxygen pressure 750kpa and oxygen flow 12800m³H, lowering the position of an oxygen lance to 1400mm, blowing oxygen for 1min, adding 875kg of lime, 400kg of light-burned magnesium balls and 1820kg of sintered ore, continuously blowing oxygen for 1.5min, adjusting the oxygen pressure to 700kpa, and adjusting the oxygen flow to 12300m³H, when the blowing is carried out for 7min, 435kg of lime is added, when the blowing is carried out for 10min, 910kg of sintering ore is added in batches, when the blowing is carried out for 11min, the position of an oxygen lance is increased to 1400mm, oxygen blowing is continued for 1min, then the oxygen pressure is adjusted to 750kpa, and the oxygen flow is 12800m³The position of the oxygen lance is reduced to 1000mm, gun pressure time of 43s, gun lifting and oxygen closing, converter reversing and temperature measurement sampling, actually measured molten steel temperature of 1642 ℃ and molten steel w [ C ]]＝0.213％、w[Mn]＝0.089％、w[P]＝0.051％、w[S]＝0.029％；

After the temperature measurement and sampling are finished, the converter is rocked to the zero position, the oxygen pressure is set to be 750kpa, the oxygen flow is set to be 12800m³After the oxygen lance position is reduced to 1000mm, the lance is pressed for 45s, the lance is lifted and oxygen is shut off, temperature measurement and sampling are carried out again, the actually measured molten steel temperature is 1663 ℃, and the molten steel w [ C ] is]＝0.079％、w[Mn]＝0.076％、w[P]＝0.029％、w[S]＝0.026％；

After smelting, the components and the temperature of the molten steel meet the process requirements, the converter normally taps steel, and qualified molten steel is obtained through deoxidation alloying operation.

TABLE 1 compounding ratio of the above Q235B steel

Note: in the table, ladle-to-ladle splashing slag iron and desulfurization splashing slag iron are mixed according to the weight ratio of 2: 1; the weight of a single piece of slag iron is less than or equal to 1000 kg.

Example 2

Smelting HRB400B steel grade, wherein the requirements of [ P ] and [ S ] of the steel grade are less than or equal to 0.045%, the content of molten iron [ Si ] is 0.37%, the temperature of the molten iron is 1343 ℃, and the height of the converter bottom is plus 100 mm;

after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 3.2t, and then carrying out slag splashing solidification and confirming;

63.4t of molten iron and 8.7t of slag iron are filled, and the converter is shaken to the zero position;

setting oxygen pressure of 900kpa, oxygen flow of 14900m3/h, igniting at a lance position of 1900mm, after oxygen blowing for 41s, adjusting the oxygen pressure to 750kpa, oxygen flow of 12900m3/h, lowering the lance position of an oxygen lance to 1320mm, blowing oxygen for 1min, adding 350kg limestone, continuously blowing oxygen for 1min, extracting the lance and closing the oxygen; switching the operation of the oxygen lance into 'nitrogen manual operation', lowering the oxygen lance to 4800mm, starting nitrogen purging for 43s, lifting the lance, closing nitrogen, tilting the converter, pouring 60% of slag, and pouring the slag for 1 min;

and after the slag dumping is finished, the converter is rocked to the zero position. Set oxygen pressure 750kpa, oxygen flow12900m³Lowering the position of an oxygen lance to 1520mm, blowing oxygen for 1min, adding 1233kg of lime, 460kg of light-burned magnesium balls and 1890kg of sintered ore, continuously blowing oxygen for 1min, adjusting the oxygen pressure to 700kpa, and adjusting the oxygen flow to 12400m³H, blowing to 7.5min, adding 620kg of lime, blowing to 9.5min, adding 950kg of sintering ore in batches, blowing to 11min, raising the lance position of an oxygen lance to 1520mm, continuously blowing oxygen for 1min, adjusting the oxygen pressure to 750kpa, the oxygen flow to 12900m3/h, lowering the lance position of the oxygen lance to 1100mm, pressing the lance for 44s, lifting the lance to close oxygen, reversing the furnace to measure the temperature and sampling, actually measuring the molten steel temperature to 1638 ℃, and taking the molten steel w [ C ]]＝0.252％、w[Mn]＝0.091％、w[P]＝0.056％、w[S]＝0.031％；

After the temperature measurement and sampling are finished, the converter is rocked to the zero position, the oxygen pressure is set to be 750kpa, and the oxygen flow is set to be 12900m³The oxygen lance position is reduced to 1100mm, the lance is pressed for 45s, the lance is lifted and oxygen is shut off, temperature measurement sampling is carried out again, the actually measured molten steel temperature is 1658 ℃, and the molten steel w [ C ]]＝0.112％、w[Mn]＝0.078％、w[P]＝0.031％、w[S]＝0.023％；

After smelting, the components and the temperature of the molten steel meet the process requirements, the converter normally taps steel, and qualified molten steel is obtained through deoxidation alloying operation.

TABLE 2 compounding ratio of the above HRB400B steel

Note: in the table, ladle-to-ladle splashing slag iron and desulfurization splashing slag iron are mixed according to the weight ratio of 2: 1; the weight of a single piece of slag iron is less than or equal to 1000 kg.

Example 3

Smelting Q355B steel grade, wherein the requirements of the steel grade [ P ] and [ S ] are less than or equal to 0.035%, the content of molten iron [ Si ] is 0.41%, the temperature of the molten iron is 1336 ℃, and the height of the converter bottom is-100 mm;

after the steel is discharged from the furnace, turning over half of the slag, controlling the slag amount to be 3.5t, and then carrying out slag splashing solidification and confirming;

charging molten iron for 62.8t and slag iron for 8.6t, and shaking the converter to a zero position;

the set oxygen pressure is 900kpa, and the oxygen flow is 14600m³The oxygen pressure is adjusted to 750kpa and the oxygen flow is 12700m after the ignition is carried out at the gun position of 1700mm and oxygen is blown for 35s³Lowering the position of an oxygen lance to 1100mm, blowing oxygen for 1min, adding 380kg limestone, continuously blowing oxygen for 1min, extracting the lance and shutting off the oxygen; the operation of the oxygen lance is switched into 'nitrogen manual operation', the oxygen lance is lowered to 4500mm, nitrogen purging is started for 29s, the oxygen lance is lifted and the nitrogen is closed, the converter is tilted, 50% of slag is poured, and the slag pouring time is 1 min;

and after the slag dumping is finished, the converter is rocked to the zero position. Set oxygen pressure 750kpa and oxygen flow 12700m³Lowering the position of an oxygen lance to 1350mm, blowing oxygen for 1min, adding 1366kg of lime, 470kg of light-burned magnesium balls and 1958kg of sintered ore, continuously blowing oxygen for 1.5min, adjusting the oxygen pressure to 700kpa, and adjusting the oxygen flow to 12400m³H, when the blowing is carried out for 7.5min, 683kg of lime is added, when the blowing is carried out for 8.5min, 980kg of sintering ore is added in batches, when the blowing is carried out for 11min, the position of an oxygen gun is increased to 1300mm, oxygen blowing is continued for 1min, then the oxygen pressure is adjusted to 750kpa, and the oxygen flow is 12700m³The oxygen lance position is reduced to 900mm, the lance pressing time is 40s, the lance is lifted and closed, the converter is turned over, the temperature is measured and the sample is taken, the actually measured molten steel temperature is 1636 ℃, and the molten steel w [ C ]]＝0.24％、w[Mn]＝0.092％、w[P]＝0.048％、w[S]＝0.027％；

After the temperature measurement and sampling are finished, the converter is rocked to the zero position, the oxygen pressure is set to be 750kpa, and the oxygen flow is set to be 12700m³After the oxygen lance position is reduced to 900mm, the lance is pressed for 48s, the lance is lifted and oxygen is shut off, temperature measurement and sampling are carried out again, the actually measured molten steel temperature is 1665 ℃, and the molten steel w [ C ] is measured]＝0.082％、w[Mn]＝0.071％、w[P]＝0.027％、w[S]＝0.021％；

After smelting, the components and the temperature of the molten steel meet the process requirements, the converter normally taps steel, and qualified molten steel is obtained through deoxidation alloying operation.

Table 3 mixing ratio of the above Q355B steel raw materials

Note: in the table, ladle-to-ladle splashing slag iron and desulfurization splashing slag iron are mixed according to the weight ratio of 2: 1; the weight of a single piece of slag iron is less than or equal to 1000 kg.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.