CN108977611B - Converter low-silicon molten iron blowing method using cast steel residues - Google Patents
Converter low-silicon molten iron blowing method using cast steel residues Download PDFInfo
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- CN108977611B CN108977611B CN201811010495.0A CN201811010495A CN108977611B CN 108977611 B CN108977611 B CN 108977611B CN 201811010495 A CN201811010495 A CN 201811010495A CN 108977611 B CN108977611 B CN 108977611B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention discloses a converter low-silicon molten iron blowing method using cast steel residual slag, which improves the condition of blowing slag melting by adding the cast steel residual slag in the blowing process, so that the converter can melt slag early, melt slag thoroughly and melt slag well in the blowing process of smelting the low-silicon molten iron, and the dephosphorization efficiency is obviously improved. The slag completely covers the molten steel surface, so that the problem of steel sticking of an oxygen lance, a furnace mouth, a smoke hood and the like caused by dry returning and splashing is solved, the loss of steel materials is reduced, the steel consumption per ton is reduced, the labor intensity is reduced, the cost is saved, the production safety is improved, and the method has good popularization and application values.
Description
Technical Field
The invention belongs to the technical field of converter blowing, and particularly relates to a converter low-silicon molten iron blowing method using cast steel residues.
Background
The use of low-silicon molten iron in the production of modern large-scale blast furnaces can bring great economic benefits to iron and steel enterprises. The silicon content of the blast furnace molten iron is reduced by 0.1 percent, and the yield can be improved by 1.0-1.5 percent. The silicon content of molten iron in large blast furnaces of various countries of the united states, japan and europe has been reduced. However, compared with the normal silicon-containing molten iron steelmaking, the decarburization reaction of the low-silicon molten iron is advanced in the smelting process, the oxidation of carbon is prior to the oxidation of silicon, and SiO in the slag2Difficult enrichment, and the early dicalcium silicate in the initial slag prevents the lime from melting, so that slagging in the early stage of blowing is difficult and the dephosphorization effect is poor. Supplementing a converter with a silicon source is the most direct method for solving many problems in the blowing process of low-silicon molten iron, and certain industrial practices have been made for supplementing silicon sources with silicon iron, river sand and silica. However, Si-Fe is expensive, and neither of river sand and silica has a complicated composition and a long melting time, and is an ideal choice for supplementing Si source.
In actual operation, when the lance position of the oxygen lance is lowered to a certain degree or a certain low lance position is used for blowing for a long time, the decarburization speed in a molten pool is high, FeO is consumed more, the TFe content is reduced, the slag is dried again, and the metal splashing phenomenon is serious. Thereby further causing serious accidents such as steel sticking of the oxygen lance and the like, not only increasing the treatment cost, but also influencing the smooth production.
When the converter blows, the furnace temperature is too high due to abundant heat, and the furnace lining is easy to be corroded by impact. And the dephosphorization reaction has stronger sensitivity to temperature in the blowing process, and the distribution ratio of phosphorus is reduced under the high-temperature condition, so that the phosphorus content in the molten steel is difficult to be reduced below the requirement. The gas dissolved in the molten steel increases, thereby affecting the quality of the steel. And casting accidents are easily caused due to overhigh temperature of tapping molten steel.
For this reason, it is very critical to develop a converter low-silicon molten iron blowing method using cast steel slag that can solve the above problems.
Disclosure of Invention
The invention aims to provide a converter low-silicon molten iron blowing method using cast steel residues.
The object of the invention is achieved by the following steps:
1) adding scrap steel into a converter, adding molten iron, setting the lance position of an oxygen lance to be 180-220 cm, and starting ignition;
2) starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 160-180 cm, and adding a slag-making material;
3) and after the steel enters the final stage of blowing, reducing the lance position of the oxygen lance to 100-120 cm, and immediately stopping blowing oxygen when the components of the molten steel meet the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, so that tapping is performed.
Compared with the prior art, the invention has the following beneficial effects:
1) in the smelting process of the converter, SiO is added2The rich cast steel slag fundamentally solves a series of problems caused by low silicon content in converter smelting, and simultaneously changes the cast steel slag as an industrial byproduct into valuable, thereby not only activating resources, but also reducing environmental pollution.
2) The steel-casting residue added in the converter blowing process is rich in TFe, so that the problems of sticking of an oxygen lance, a furnace mouth, a smoke hood and the like caused by drying return and splashing are solved, the loss of steel and iron materials is reduced, the labor intensity is reduced, the cost is saved, the production safety is improved, and the method has good popularization and application values.
3) The invention adds the scrap steel as the coolant before the blowing, so that the converter achieves the heat balance in the blowing process and reaches the qualified temperature. Can reduce the consumption of steel materials, slagging materials and oxygen, and has stable cooling effect, less splashing and good dephosphorization effect compared with the iron ore adopted in the conventional process.
4) The steel-casting residue added in the converter blowing process contains a large amount of Al2O3, MnO and CaO, and can replace a part of slag-making materials, so that the requirement of the slag-making materials in the smelting process is reduced, the cost is saved, and the utilization of the steel-casting residue resources is maximized.
Detailed Description
The present invention is further illustrated by the following examples, which are not intended to be limiting in any way, and any modifications or alterations based on the teachings of the present invention are intended to fall within the scope of the present invention.
The converter low-silicon molten iron blowing method using the cast steel slag comprises the following steps:
1) adding scrap steel into a converter, adding molten iron, setting the lance position of an oxygen lance to be 180-220 cm, and starting ignition;
2) starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 160-180 cm, and adding a slag-making material;
3) and after the steel enters the final stage of blowing, reducing the lance position of the oxygen lance to 100-120 cm, and immediately stopping blowing oxygen when the components of the molten steel meet the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, so that tapping is performed.
The silicon content of the molten iron in the step 1) is less than 0.15%.
And (3) finishing adding the casting steel residues in the step 2) within 5min after the beginning of converting.
The cast steel slag in the step 2) comprises the following components in percentage by weight：SiO223%-30%、TFe20~25%、Al2O312%-14%、MnO18% –21%、CaO15~20%。
The slag former in the step 2) is added in 8-12 batches, and the weight of the slag former added in each batch is 0.1-0.4% of that of molten iron.
The slagging material in the step 2) comprises the following components in percentage by weight: 50-60% of lime, 30-40% of light-burned dolomite and 5-10% of magnesite balls.
The oxygen supply constant pressure of the oxygen lance is 0.78-0.82 MPa.
The flow of the oxygen lance is 22800-24000 m3/h。
The weight of the scrap steel in the step 1) is 4% -14% of that of the molten iron.
The weight of the cast steel slag in the step 2) is 0.75-1% of that of the molten iron.
Example 1
1) Adding scrap steel and molten iron into a converter, setting the lance position of an oxygen lance to be 180cm, and starting ignition; the silicon content of the molten iron is 0.05%; the weight of the scrap steel is 4% of that of the molten iron; the oxygen supply constant pressure of the oxygen lance is 0.78 Mpa; the flow of the oxygen lance is 22800m3/h；
2) Starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 160cm, and adding a slag-making material; and the steel casting residue is added within 5min after the beginning of converting. The cast steel residue comprises the following components in percentage by weight: SiO228%, TFe 22%, Al2O313%, MnO18% and CaO 19%. The addition mode of the slagging material is divided into 8 batches, and the weight of the slagging material added in each batch is 0.1 percent of that of the molten iron. The slagging material comprises the following components in percentage by weight: 50% of lime, 40% of light-burned dolomite and 10% of magnesite balls. The weight of the cast steel slag is 0.75 percent of that of the molten iron.
3) After the end of blowing, the lance position of the oxygen lance is reduced to 100cm, and when the components of the molten steel reach the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, the oxygen blowing is stopped immediately, and the steel is tapped.
Example 2
1) Adding scrap steel and then iron into the converterSetting the lance position of the oxygen lance to 190cm, and starting ignition; the silicon content of the molten iron is 0.08%; the weight of the scrap steel is 8 percent of that of the molten iron; the oxygen supply constant pressure of the oxygen lance is 0.79 MPa; the flow of the oxygen lance is 23000m3/h；
2) Starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 170cm, and adding a slag-making material; and the steel casting residue is added within 5min after the beginning of converting. The cast steel residue comprises the following components in percentage by weight: 230% of SiO, 25% of TFe, 312% of Al2O, 18% of MnO and 15% of CaO. The addition mode of the slagging material is divided into 9 batches, and the weight of the slagging material added in each batch is 0.2 percent of that of the molten iron. The slagging material comprises the following components in percentage by weight: 55% of lime, 38% of light-burned dolomite and 7% of magnesite balls. The weight of the cast steel slag is 0.85 percent of that of the molten iron.
3) After the end of the blowing, the lance position of the oxygen lance is reduced to 105cm, and when the components of the molten steel reach the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, the oxygen blowing is stopped immediately, and the steel is tapped.
Example 3
1) Adding scrap steel and molten iron into a converter, setting the lance position of an oxygen lance to be 200cm, and starting ignition; the silicon content of the molten iron is 0.1%; the weight of the scrap steel is 10 percent of that of the molten iron; the oxygen supply constant pressure of the oxygen lance is 0.81 MPa; the flow of the oxygen lance is 23500m3/h；
2) Starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 175cm, and adding a slag-making material; and the steel casting residue is added within 5min after the beginning of converting. The cast steel residue comprises the following components in percentage by weight: SiO223%, TFe 22%, Al2O314%, MnO21% and CaO 20%. The addition mode of the slag making materials is divided into 10 batches, and the weight of each batch is 0.3 percent of that of the molten iron. The slagging material comprises the following components in percentage by weight: 58% of lime, 37% of light-burned dolomite and 5% of magnesite balls. The weight of the cast steel slag is 0.9 percent of that of the molten iron.
3) After the end of blowing, the lance position of the oxygen lance is reduced to 110cm, and when the components of the molten steel reach the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, the oxygen blowing is stopped immediately, and the steel is tapped.
Example 4
1) Adding scrap steel and molten iron into a converter, setting the lance position of an oxygen lance to be 220cm, and starting ignition; the silicon content of the molten iron is 0.15%; the weight of the scrap steel is 14 percent of that of the molten iron; the oxygen supply constant pressure of the oxygen lance is 0.82 MPa; the flow of the oxygen lance is 24000m3/h；
2) Starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 180cm, and adding a slag-making material; and the steel casting residue is added within 5min after the beginning of converting. The cast steel residue comprises the following components in percentage by weight: 226% of SiO, 24% of TFe, 314% of Al2O, 18% of MnO and 18% of CaO. The addition mode of the slag making materials is divided into 12 batches, and the weight of each batch is 0.4 percent of that of the molten iron. The slagging material comprises the following components in percentage by weight: 60% of lime, 30% of light-burned dolomite and 10% of magnesite balls. The weight of the cast steel slag is 1 percent of that of the molten iron.
3) After the end of blowing, the lance position of the oxygen lance is reduced to 120cm, and when the components of the molten steel reach the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, the oxygen blowing is stopped immediately, and the steel is tapped.
Test example 1
In the following test examples, furnace E used the conventional process and furnace F used the converting method of example 3.
In 2017, in 4 months, the furnace cap of the slag pouring surface of the furnace No. E in the new area is fettled for 4 times, the furnace cap of the steel tapping surface is fettled for 3 times, and the using amount of fettled sand in each fettler is 2 tons, and is totally 14 tons; the furnace head of the slag pouring surface of the furnace F is fettled for 2 times, the furnace head of the steel tapping surface is fettled for 1 time, the using amount of fettled sand in each fettler is 2 tons, and 6 tons in total, the using amount of fettled sand in the furnace F after 4 months is less than that in the furnace E, and 8 tons of fettled sand are used. According to the sand calculation of 2300 yuan/ton fettling, the No. 4 month furnace of the No. F furnace is equivalent to the No. 4 month furnace of the No. E furnace, and the No. 18400 yuan.
Test example 2
In 4 months in 2017, the steel yield of the furnace No. E in the new district is 8.6 ten thousand tons, and the consumption of steel materials is 1076kg per ton of steel; the steel yield of the furnace F is 9 ten thousand tons, and the consumption of steel materials is 1072kg per ton of steel. According to the calculation of the processing cost of saving 2 yuan for each 1kg of steel and iron materials per ton of steel, the furnace F saves 72 ten thousand yuan for the furnace E with the same comparison in 4 months.
Test example 3
In 4 months in 2017, 20 heavy guns are consumed by the furnace No. E in the new district, 12 heavy guns are consumed by the furnace No. F, and 8 heavy guns are less than those of the furnace No. E in 4 months in the furnace No. F.
Claims (3)
1. A converter low-silicon molten iron blowing method using cast steel residues is characterized by comprising the following steps:
1) adding scrap steel into a converter and then adding molten iron, setting the lance position of an oxygen lance to be 180-220 cm, and setting the oxygen supply constant pressure of the oxygen lance to be 0.78-0.82 MPa and the flow to be 22800-24000 m3H, starting ignition;
2) starting blowing after ignition is successful, simultaneously adding the steel-casting residue into a converter from a high-level bunker, continuously blowing until initial slag is formed, reducing the lance position of an oxygen lance to 160-180 cm, and adding a slag-making material; the cast steel slag comprises the following components in percentage by weight: SiO2223%-30%、TFe 20~25%、Al2O312-14%, 18-21% of MnO and 15-20% of CaO, wherein the weight of the casting steel slag is 0.75-1% of that of molten iron, and the addition is completed within 5min after the blowing is started; the slagging material comprises the following components in percentage by weight: 50-60% of lime, 30-40% of light-burned dolomite and 5-10% of magnesite balls, wherein the slag-making materials are added in 8-12 batches, and the weight of each batch is 0.1% -0.4% of molten iron;
3) and after the steel enters the final stage of blowing, reducing the lance position of the oxygen lance to 100-120 cm, and immediately stopping blowing oxygen when the components of the molten steel meet the requirement of smelting steel seeds and the temperature reaches the tapping temperature of the smelting steel seeds, so that tapping is performed.
2. The method for converting low-silicon molten iron in a converter using cast steel slag according to claim 1, wherein the molten iron of step 1) has a silicon content of less than 0.15%.
3. The method for converting converter low-silicon molten iron using cast steel slag according to claim 1, wherein the weight of the scrap steel in the step 1) is 4-14% of the molten iron.
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| CN101117651B (en) * | 2006-07-31 | 2010-10-13 | 宝山钢铁股份有限公司 | Converting process for converter low-silicon molten iron |
| CN102994689B (en) * | 2012-11-30 | 2014-09-17 | 武钢集团昆明钢铁股份有限公司 | Method for heat application of low-alkalinity casting residue in steel-making |
| CN103555878B (en) * | 2013-11-25 | 2015-02-04 | 武钢集团昆明钢铁股份有限公司 | Safe and high-efficient low-silicon molten-ion blowing process |
| CN103710484A (en) * | 2014-01-06 | 2014-04-09 | 鞍钢股份有限公司 | Silicon recycling method for controlling casting residue to be recycled to low-silicon steel |
| CN104711388B (en) * | 2015-02-04 | 2016-09-07 | 北京科技大学 | A kind of hot metal containing low silicon converting method |
| CN105219913A (en) * | 2015-11-10 | 2016-01-06 | 湖南华菱湘潭钢铁有限公司 | A kind of method optimizing converter slag-making |
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