CN113667794A - Method for manufacturing early-stage slag by using self-circulation slag pellets - Google Patents

Method for manufacturing early-stage slag by using self-circulation slag pellets Download PDF

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CN113667794A
CN113667794A CN202110768125.9A CN202110768125A CN113667794A CN 113667794 A CN113667794 A CN 113667794A CN 202110768125 A CN202110768125 A CN 202110768125A CN 113667794 A CN113667794 A CN 113667794A
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slag
stage
early
self
pellets
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潘佳
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Yangchun New Iron and Steel Co Ltd
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Yangchun New Iron and Steel Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/36Processes yielding slags of special composition
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00Technologies relating to the processing of minerals
    • Y02P40/40Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention provides a method for using self-circulation slag pellets to make early-stage slag, which relates to the technical field of converter steelmaking and comprises the following steps: feeding control, gun position control, oxygen supply flow control, judgment of gun lifting conditions and slag pressing operation; the self-circulation slag pellets are used, the slagging environment is improved, the lime consumption is reduced, the early-stage slag alkalinity is improved, the corrosion to a furnace lining is reduced, the slag pellets are recycled, and the discharge of three wastes is reduced.

Description

Method for manufacturing early-stage slag by using self-circulation slag pellets
Technical Field
The invention relates to the technical field of converter steelmaking, in particular to a method for manufacturing early-stage slag by using self-circulation slag pellets.
Background
The molten iron in the steel-making branch plant has unstable components and large fluctuation, particularly, the content of silicon and phosphorus far exceeds the normal range, in order to reduce the content of harmful element phosphorus in steel and improve the quality of the variety of steel, aiming at the molten iron conditions, special early-stage slag-making operation of a converter is carried out, the dephosphorization in the initial stage of steel making is ensured, the dephosphorization effect is basically not carried out or less, the quality of the molten steel is greatly improved, and the production cost is reduced;
the existing early-stage slag forming methods mainly comprise two methods, wherein one method is that the early-stage slag forming operation is directly carried out by adopting final slag without increasing slag materials, the final slag is end-point slag left by a furnace, but the alkalinity of the early-stage slag is too low, and the corrosion to a furnace lining is large; the other method is to add metallurgical lime for slagging operation, which is not beneficial to reducing lime consumption, and both methods are easy to cause the situation that the furnace cannot be shaken, so that the smelting period is increased.
Disclosure of Invention
Aiming at the problems, the invention provides a method for manufacturing early-stage slag by using self-circulation slag pellets, which improves the slagging environment, reduces the lime consumption, improves the early-stage slag alkalinity, reduces the corrosion to a furnace lining, recycles the slag pellets and reduces the discharge of three wastes.
In order to realize the purpose of the invention, the invention is realized by the following technical scheme: the method for manufacturing the early-stage slag by using the self-circulation slag pellets comprises the following steps:
the method comprises the following steps: charge control
Under the condition of completely remaining slag or half remaining slag, 1200kg of self-circulation slag pellets are added into the furnace, when the phosphorus content of molten iron is more than 0.15 percent during half remaining slag, 300kg of lime is added for slagging, under the condition of an empty furnace, 1200kg of self-circulation slag pellets are added into the furnace, 1200kg of lime is added for slagging, and when the temperature of the molten iron is less than 1280 ℃, 900kg of self-circulation slag pellets are added into the furnace;
step two: gun position control
Under the condition of full slag remaining, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.5-1.7 m, and under the condition that the temperature of an empty furnace, half slag remaining and molten iron is lower than 1280 ℃, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.7 m;
step three: slag flow control in early stage of construction
When the early-stage slag is produced, an oxygen lance is used for automatically supplying oxygen to the furnace, and the oxygen supply flow rate is 26000m in the first stage of 0-15s3The flow rate of oxygen supply is 27000m in 15-45s in the second stage3H, the third stage is 45-150s, and the oxygen flow rate is 26000m3H, after the fourth stage for 150s, the oxygen flow rate is controlled to 25000m3/h;
Step four: condition of batch gun lifting
In the gas generated by the reaction, when the content of carbon monoxide is 25-35%, and the slag in the early stage of the manufacture is 4.5-5 min, both conditions are met, the slag in the early stage is removed, and the gun is lifted and the slag is poured;
step five: slag pressing operation
Adding 300kg-500kg of self-circulation slag pellets 5-10s before lifting the lance, manually closing oxygen supply when the lance is lifted to 4m, opening nitrogen supply, continuously lifting the lance to a position to be blown after the lance stays for 5s, controlling the total nitrogen supply time to be 10-15s, and then lifting the lance to discharge slag.
The further improvement lies in that: in the first step, when the phosphorus content of the molten iron is more than 0.15%, 300kg of lime is added for slagging, the total amount of the lime is added according to the standard upper limit, in the first step, the lime is not added when the slag is completely remained, and the lime is not added when the temperature of the molten iron is less than 1280 ℃.
The further improvement lies in that: in the second step, the lance position of the early-stage slag oxygen lance is the height from the nozzle to the liquid level.
The further improvement lies in that: in the third step, in the oxygen supply process, oxygen is used for blowing the slag surface, and the oxygen supply pressure is controlled to be 0.9-1 MPa.
The further improvement lies in that: in the fourth step, before the slag is formed in the early stage, the flame contraction condition and slag sheets at the furnace mouth are concerned, and when the obvious splashing sign appears, slag pouring of a pilot gun is carried out.
The further improvement lies in that: in the fifth step, the pressure of nitrogen supply is controlled to be 8-15MPa, and when the pressure of the nitrogen is insufficient, the nitrogen supply time is prolonged to 2min at most.
The further improvement lies in that: in the fifth step, when the position to be blown is 5 meters away from the liquid level, the gun is lifted to discharge slag when the nitrogen is blown to the furnace mouth and slag particles are visible to jump.
The invention has the beneficial effects that:
1. the invention uses the self-circulation slag pellets, improves the slagging environment, reduces the lime consumption, improves the early-stage slag alkalinity, reduces the corrosion to the furnace lining, recycles the slag pellets and reduces the discharge of three wastes.
2. The invention utilizes the high-speed nitrogen ejected by the jet flow of the oxygen lance to defoam the foam slag, breaks the foaming state of the slag and reduces the thickness of the slag layer, thus greatly reducing the iron content in the foam slag.
3. The self-circulation slag pellets are added before the gun is lifted, so that the effects of quickly cooling and reducing the volume of the slag are achieved, the oxygen is manually turned off and the nitrogen is turned on after the gun is lifted, the separation of slag and iron is promoted, the iron content in the slag is reduced, the foaming degree of the slag is reduced, the slag pouring time is shortened, and the double-slag smelting period is shortened.
Drawings
FIG. 1 is a flow chart of the present invention.
Detailed Description
In order to further understand the present invention, the following detailed description will be made with reference to the following examples, which are only used for explaining the present invention and are not to be construed as limiting the scope of the present invention.
As shown in fig. 1, the present embodiment provides a method for manufacturing early-stage slag by using self-circulation slag pellets, which comprises the following steps:
the method comprises the following steps: charge control
Under the condition of completely remaining slag or half remaining slag, 1200kg of self-circulation slag pellets are added into the furnace, lime is not added when the slag is completely left, 300kg of lime is added during half remaining slag when the phosphorus content of molten iron is more than 0.15 percent, the total amount of the lime is added according to the standard upper limit, under the condition of an empty furnace, 1200kg of self-circulation slag pellets are added into the furnace, 1200kg of lime is added during slag making, and when the temperature of the molten iron is less than 1280 ℃, 900kg of self-circulation slag pellets are added into the furnace, lime is not added, the self-circulation slag pellets can improve the slag forming environment, reduce the lime consumption, improve the early-stage slag alkalinity and reduce the corrosion to a furnace lining;
Figure BDA0003151511200000041
step two: gun position control
Under the condition of full slag remaining, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.5-1.7 m, the gun position is the height from the spray head to the liquid level, and under any one of the conditions that the temperature of an empty furnace, half slag remaining and molten iron is less than 1280 ℃, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.7 m, and the gun position is the height from the spray head to the liquid level;
step three: slag flow control in early stage of construction
When the early-stage slag is produced, an oxygen lance is used for automatically supplying oxygen to the furnace, and the oxygen supply flow rate is 26000m in the first stage of 0-15s3The flow rate of oxygen supply is 27000m in 15-45s in the second stage3H, the third stage is 45-150s, and the oxygen flow rate is 26000m3H, after the fourth stage for 150s, the oxygen flow rate is controlled to 25000m3Blowing the slag surface by using oxygen in the oxygen supply process, and controlling the oxygen supply pressure to be 0.9-1 MPa;
Time 0~15s 15~45s 45~150s >150s
phases First stage Second stage The third stage Fourth stage
Flow rate 26000m3/h 27000m3/h 26000m3/h 25000m3/h
Step four: condition of batch gun lifting
In gas generated by reaction, when the content of carbon monoxide is 25% -35%, and slag is generated in the early stage of slag production for 4.5-5 min, both conditions are met, early stage slag generation is carried out, before the early stage slag generation, the flame contraction condition and slag pieces at a furnace mouth are concerned, and when obvious splashing signs appear, slag pouring of a pilot gun is carried out;
step five: slag pressing operation
300kg-500kg of self-circulation slag pellets are added 5-10s before the gun is lifted to play a role in quickly cooling and reducing the volume of the slag, oxygen supply is manually closed when the gun is lifted to 4m, nitrogen supply is opened, the gun is continuously lifted to a position to be blown after 5s of stopping, the position to be blown is 5m away from the liquid level, the total nitrogen supply time is controlled to be 10-15s, the pressure of the nitrogen supply is controlled to be 8-15MPa, when the nitrogen pressure is insufficient, the nitrogen supply time is prolonged to be 2min at most, slag-iron separation is promoted, the iron content in the slag is reduced, the foaming degree of the slag is reduced, the slag pouring time is shortened, the double-slag smelting period is reduced, and when the nitrogen splashes to the furnace mouth, the slag particles can jump, the gun is lifted to discharge the slag.
The method for manufacturing early-stage slag by using the self-circulation slag pellets improves the slagging environment, reduces lime consumption, improves early-stage slag alkalinity, reduces corrosion to a furnace lining, recycles the slag pellets and reduces discharge of three wastes, and the method utilizes high-speed nitrogen jetted by jet flow of an oxygen lance to defoam foam slag, breaks the foaming state of slag and reduces the thickness of a slag layer, thereby greatly reducing the iron content in the foam slag, and because the density of the iron content in the slag is greater than that of the slag, the molten metal in the slag sinks when the slag is knocked by using nitrogen, so as to realize separation of the slag and the molten metal, thereby achieving the purpose of reducing the iron content in the slag, meanwhile, the self-circulation slag pellets are added before the gun is lifted to play a role in rapidly cooling and reducing the volume of the slag, the nitrogen is manually turned off and on after the gun is lifted, the separation of the slag and the iron content in the slag are reduced, meanwhile, the foaming degree of the furnace slag is reduced, the deslagging time is shortened, and the double-slag smelting period is shortened.
The foregoing illustrates and describes the principles, general features, and advantages of the present 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. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (7)

1. The method for manufacturing early-stage slag by using the self-circulation slag pellets is characterized by comprising the following steps of:
the method comprises the following steps: charge control
Under the condition of completely remaining slag or half remaining slag, 1200kg of self-circulation slag pellets are added into the furnace, when the phosphorus content of molten iron is more than 0.15 percent during half remaining slag, 300kg of lime is added for slagging, under the condition of an empty furnace, 1200kg of self-circulation slag pellets are added into the furnace, 1200kg of lime is added for slagging, and when the temperature of the molten iron is less than 1280 ℃, 900kg of self-circulation slag pellets are added into the furnace;
step two: gun position control
Under the condition of full slag remaining, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.5-1.7 m, and under the condition that the temperature of an empty furnace, half slag remaining and molten iron is lower than 1280 ℃, the gun position of the early-stage slag oxygen lance is controlled according to 2.1-1.9-1.7 m;
step three: flow control of oxygen supply
When the early-stage slag is produced, an oxygen lance is used for automatically supplying oxygen to the furnace, and the oxygen supply flow rate is 26000m in the first stage of 0-15s3The flow rate of oxygen supply is 27000m in 15-45s in the second stage3H, the third stage is 45-150s, and the oxygen flow rate is 26000m3H, after the fourth stage for 150s, the oxygen flow rate is controlled to 25000m3/h;
Step four: judging the condition of lifting the gun
In the gas generated by the reaction, when the content of carbon monoxide is 25-35%, and the slag in the early stage of the manufacture is 4.5-5 min, both conditions are met, the slag in the early stage is removed, and the gun is lifted and the slag is poured;
step five: slag pressing operation
Adding 300kg-500kg of self-circulation slag pellets 5-10s before lifting the lance, manually closing oxygen supply when the lance is lifted to 4m, opening nitrogen supply, continuously lifting the lance to a position to be blown after the lance stays for 5s, controlling the total nitrogen supply time to be 10-15s, and then lifting the lance to discharge slag.
2. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 1, wherein the method comprises the following steps: in the first step, when the phosphorus content of the molten iron is more than 0.15%, 300kg of lime is added for slagging, the total amount of the lime is added according to the standard upper limit, in the first step, the lime is not added when the slag is completely remained, and the lime is not added when the temperature of the molten iron is less than 1280 ℃.
3. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 1, wherein the method comprises the following steps: in the second step, the lance position of the early-stage slag oxygen lance is the height from the nozzle to the liquid level.
4. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 1, wherein the method comprises the following steps: in the third step, in the oxygen supply process, oxygen is used for blowing the slag surface, and the oxygen supply pressure is controlled to be 0.9-1 MPa.
5. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 1, wherein the method comprises the following steps: in the fourth step, before the slag is formed in the early stage, the flame contraction condition and slag sheets at the furnace mouth are concerned, and when the obvious splashing sign appears, slag pouring of a pilot gun is carried out.
6. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 1, wherein the method comprises the following steps: in the fifth step, the pressure of nitrogen supply is controlled to be 8-15MPa, and when the pressure of the nitrogen is insufficient, the nitrogen supply time is prolonged to 2min at most.
7. The method for manufacturing the early-stage slag by using the self-circulation slag pellets as claimed in claim 6, wherein the method comprises the following steps: in the fifth step, when the position to be blown is 5 meters away from the liquid level, the gun is lifted to discharge slag when the nitrogen is blown to the furnace mouth and slag particles are visible to jump.
CN202110768125.9A 2021-07-07 2021-07-07 Method for manufacturing early-stage slag by using self-circulation slag pellets Pending CN113667794A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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RU2009133799A (en) * 2007-02-09 2011-03-20 Смс Зимаг Аг (De) METHOD FOR RESTORING HIGH CHROMIUM SLAG IN AN ELECTRIC ARC FURNACE
CN103352101A (en) * 2013-06-21 2013-10-16 江苏省沙钢钢铁研究院有限公司 Low-cost smelting technology of converter
CN109385522A (en) * 2018-12-18 2019-02-26 攀钢集团攀枝花钢铁研究院有限公司 A kind of oxide scale slag pelletizing and its preparation method and application
CN110484679A (en) * 2018-03-27 2019-11-22 上海梅山钢铁股份有限公司 A kind of control method of the double slag meltings of converter
CN112779378A (en) * 2020-12-15 2021-05-11 阳春新钢铁有限责任公司 Low-iron-consumption duplex less-slag smelting method for single converter

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RU2009133799A (en) * 2007-02-09 2011-03-20 Смс Зимаг Аг (De) METHOD FOR RESTORING HIGH CHROMIUM SLAG IN AN ELECTRIC ARC FURNACE
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CN103352101A (en) * 2013-06-21 2013-10-16 江苏省沙钢钢铁研究院有限公司 Low-cost smelting technology of converter
CN110484679A (en) * 2018-03-27 2019-11-22 上海梅山钢铁股份有限公司 A kind of control method of the double slag meltings of converter
CN109385522A (en) * 2018-12-18 2019-02-26 攀钢集团攀枝花钢铁研究院有限公司 A kind of oxide scale slag pelletizing and its preparation method and application
CN112779378A (en) * 2020-12-15 2021-05-11 阳春新钢铁有限责任公司 Low-iron-consumption duplex less-slag smelting method for single converter

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Application publication date: 20211119