CN108998620B - Slag-iron separation method - Google Patents
Slag-iron separation method Download PDFInfo
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- CN108998620B CN108998620B CN201811131805.4A CN201811131805A CN108998620B CN 108998620 B CN108998620 B CN 108998620B CN 201811131805 A CN201811131805 A CN 201811131805A CN 108998620 B CN108998620 B CN 108998620B
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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
- C21C5/36—Processes yielding slags of special composition
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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
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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
- C21C5/32—Blowing from above
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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
- C21C5/36—Processes yielding slags of special composition
- C21C2005/366—Foam slags
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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 provides a slag-iron separation method, which promotes the early-stage slag-iron to be rapidly separated in the double-slag operation of a converter by controlling and adopting corresponding technical means, reduces the iron content in the early-stage slag to the maximum extent, realizes the rapid slag pouring of the converter, can ensure the metallurgical effect of less slag and consumption reduction of the double-slag method, shortens the smelting period of the double-slag operation of the converter, and ensures the stability and continuity of the steelmaking production of the converter.
Description
Technical Field
The invention belongs to the technical field of steel making, and particularly relates to a method for separating slag from iron, which is used for reducing the iron content in early-stage slag when a converter adopts a double-slag method for steel making.
Background
The converter uses the high-silicon molten iron for steelmaking, on one hand, splashing smoke is easily caused to pollute the environment, so that the metal loss is increased, according to the statistics of relevant manufacturers, the metal loss is about 3.6% during large spraying, and about 1.2% during small spraying, and researches also consider that the metal loss caused by the splashing is 0.5% -5%, the splashing is prevented from being equal to the increase of the steel yield, and meanwhile, the splashing can seriously scour the furnace lining, even cause accidents, and influence the production stability; on the other hand, the high silicon content of the molten iron leads to large slag formation amount of the converter, the consumption of slag materials such as lime and the like and the consumption of iron and steel materials are obviously increased, and the production cost of steel making is increased. When the molten iron (Si%) of the converter is more than or equal to 0.50%, a double-slag method can be adopted, particularly, the operation of the double-slag-remaining method can not only effectively avoid the splashing of the converter, but also realize the low-slag smelting of the converter, improve the early dephosphorization rate and reduce the slag material consumption and the iron and steel material consumption of the converter.
Partial early-stage slag needs to be poured out during the double-slag operation of the converter, the problem that the early-stage slag has large iron content and needs to be solved by the double-slag operation process is solved, and the iron content in the early-stage slag reaches 20-33% according to statistics. A large amount of metal iron beads are often suspended in early-stage slag, the metal iron beads are poured into a slag pot along with the slag in the slag pouring process, firstly, metal loss is caused, secondly, the slag is poured into the slag pot from a converter, and under the impact stirring action of slag flow, carbon in the iron beads and (FeO) in the slag further react at high temperature to generate CO gas, the slag foams and expands in the slag pot again, the volume is increased sharply, and then the slag overflows from the slag pot, even slag car equipment is burnt out, and the slag pouring operation cannot be continued. The settled metallic iron is welded at the bottom of the slag pot after being condensed and is not easy to be treated, and the reuse of the slag pot is influenced.
In the prior art, the purpose of slag-iron separation is achieved by methods of spraying nitrogen by an oxygen lance to remove slag, adding a foam slag inhibitor, precipitating and calming in a vertical furnace and the like, and the methods are usually long in treatment time. The method has the advantages that 1-3 minutes are needed for one-time slagging by only using nitrogen, and even multiple times of slagging is needed sometimes, so that the treatment time is long and the nitrogen consumption is large; the foam slag inhibitor is an artificially synthesized material, is expensive, and is added into 200Kg of the foam slag inhibitor at one time, so that the cost is increased; and the vertical furnace deposition sedation takes time to ensure the effect. Under the production mode of converter steelmaking-continuous casting, strict requirements are imposed on the smelting period of the converter, and the stability and continuity of production can be directly influenced by overlong double-slag time.
Chinese patent document (CN 107674936A) is a slag-iron separation control method for smelting a titanium-containing molten iron converter terminal, which adopts a slag-making mode mainly using active lime and ore, wherein the active lime requires that the effective CaO is more than or equal to 85%. The converter adopts a selective slag remaining and single slag operation method, namely, slag remaining operation is carried out on the converter slag remaining amount according to 1/2-2/3 of the total slag amount. The converter loading is produced according to a mode of 90% molten iron and 10% scrap steel, and the specific smelting process of the converter is divided into two parts: the first part is smelting slagging operation; the second part is the slag-iron separation operation in the tapping process. Because the earlier-stage slag and the final-stage slag of the converter have larger difference in components and temperature, the patent cannot solve the problem of large iron content in the slag during the earlier-stage slag dumping of the double-slag operation of the converter.
Disclosure of Invention
In order to overcome the defects and shortcomings of the prior art, the invention provides a slag-iron separation method, which aims to promote the early-stage slag-iron separation in the double-slag operation of a converter by controlling and adopting corresponding technical means, reduce the iron content in the early-stage slag to the maximum extent, realize the quick slag pouring of the converter, ensure the metallurgical effect of less slag and consumption reduction of the double-slag method, shorten the smelting period of the double-slag operation of the converter and ensure the stability and continuity of the steelmaking production of the converter.
The invention adopts the following specific technical scheme:
a slag-iron separation method comprising the steps of:
1) earlier-stage slagging of the converter:
1-1) during continuous production of a converter, performing slag splashing protection, splashing drying and solidification on end-point slag discharged from the last converter, then keeping the end-point slag in the converter, adopting a slag-remaining operation, clicking a 'hot metal adding and scrap steel adding' key on a main converting picture of the converter after confirmation, accelerating a dust removal fan to a proper position, and performing hot metal adding and scrap steel adding operations;
1-2) finishing the operation of adding molten iron and scrap steel, shaking the converter mouth upwards to a zero position in a main control chamber, clicking to start main blowing, putting a gun down for ignition, and quickly lowering the gun to a low gun position with a nozzle reaching 1.2-1.3 m of the metal liquid level for blowing after the oxygen gun is successfully ignited, wherein the oxygen supply intensity is 3.06Nm3Min/t, the end-point slag alkalinity remained in the furnace is 2.8-3.2, the MgO content is 8-10%, and the FeO content is 15-22%;
1-3) and blowing oxygen for 3-5 minutes, wherein the CO concentration of the flue gas reaches 10% -20%, and the gun is lifted and blowing is stopped;
2) separating slag from iron:
2-1), shaking the converter from the zero position to the slag pouring side in front of the converter to an angle that the slag in the converter is flush with the lower edge of the inner edge of the slag pouring side furnace mouth and the slag is not poured out, stopping shaking the converter, wherein the tilting angle reflects the height condition of the slag liquid level in the converter, and then shaking the converter upwards to the zero position with the furnace mouth upwards;
2-2) determining a specific treatment method according to the height condition of the liquid level of the slag in the furnace reflected by the tilting angle;
3) and early-stage slag pouring amount control:
the early deslagging amount is controlled according to 1/2-2/3 of the total slag amount in the furnace.
Further, in the step 1-1), if the first furnace is produced after furnace repairing or maintenance, bottom slag does not exist in the furnace, and molten iron and scrap steel adding operation is directly carried out after the dedusting fan is accelerated to be in place.
In the step 1-2), no slag charge is added in the blowing process. The method has the advantages that the low lance position is adopted, the stirring is enhanced, and the remained bottom slag has certain FeO content, so that the early-stage rapid slagging is facilitated; the slag material is not added, so that the early-stage slag is well melted, and the early-stage slag components are controlled within the range required by the double-slag effect.
In the step 1-2), preferably, the alkalinity of the double-slag early-stage slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%, so that the double-slag early-stage dephosphorization is facilitated, the slag viscosity is reduced, and the iron content in the slag is reduced.
The end slag is the slag at the end of converter smelting, in order to complete the basic task of converter steelmaking and meet the requirements of furnace body maintenance, various slag-forming materials are added in batches in the converter smelting process, and after partial early-stage slag is poured out by the double-slag method, the slag-forming materials are required to be added for re-slagging when the converter is blown by an oxygen lance again, so that the end slag component is greatly different from the initial slag whether the converter steelmaking adopts the single-slag method or the double-slag method, and the alkalinity and MgO content of the end slag are obviously higher than those of the initial slag. After the steel is discharged, the slag is left in the furnace, high-pressure nitrogen is injected by an oxygen lance to perform slag splashing protection, one part of slag is splashed and coated on the inner surface of a lining to form a slag splashing layer to play a role in protecting the lining bricks of the furnace, the other part of slag is left in the furnace for the next furnace after being splashed, the part of slag is also called bottom slag, and the part of bottom slag is poured into a slag pot when the furnace is replenished or the slag remaining operation is not performed. The double slag is made on the premise of slag remaining, because open blowing is adopted without adding any slag material, the quality of CaO and MgO in the slag is basically unchanged, and metal materials (molten iron and scrap steel), particularly Si, Mn, P and other elements in the molten iron are oxidized to generate SiO2、MnO、P2O5When the slag enters the slag, the slag quantity is increased, the original bottom slag is diluted, FeO participates in the physicochemical reaction in the furnace, and the content of FeO is related to the blowing lance position, the oxygen supply intensity, the carbon-oxygen reaction speed and the like, so that the formed early-stage slag is more favorable than the slag formed in the prior artThe concentration of each component of the bottom slag originally remained in the furnace is greatly changed, and the alkalinity (R is the mass fraction of CaO in the slag/SiO in the slag)2The weight fraction), the MgO content and the FeO content are all reduced and can reach the range to be controlled, namely the alkalinity is 1.3-1.5, the MgO content is less than or equal to 7.5 percent, and the FeO content is 9-15 percent. The key to this step is: and (2) making double slag on the premise of slag remaining, without adding slag-making materials, fully utilizing the bottom slag remaining in the furnace to make early-stage slag, and making double slag on the premise of no slag remaining, wherein the adding amount of the slag-making materials such as lime, dolomite and the like is calculated according to the specific conditions of molten iron components, the alkalinity is controlled to be 1.3-1.5, and the MgO content is controlled to be less than or equal to 7.5%. And performing double slag under the two conditions, wherein the FeO content of the early-stage slag can be controlled by blowing oxygen for 3-5 minutes, the CO concentration of the flue gas is 10-20%, and the lance is lifted and stops blowing when the flame at the furnace mouth is obviously soft and shaken, so that the required range of 9-15% is reached.
More preferably, in step 1-2), the average basicity is 1.43, the average MgO content is 5.1% and the FeO content is 13.8%.
In the step 1-2), a first furnace is produced after furnace repairing or maintenance, no bottom slag exists in the furnace, slag charge is required to be added for slagging when the converter is started to blow, the alkalinity is controlled according to 1.3-1.5, and the MgO content is controlled to be less than or equal to 7.5%.
And in the step 1-3), oxygen is blown for 3-5 minutes, the concentration of CO in the flue gas reaches 10% -20%, and when flame at a furnace mouth is obviously softened and shaken, the slag is well melted at the initial stage, and the gun is lifted and blowing is stopped. The operation of the next step is prepared while this is being held. The method aims to control the appropriate foaming degree of the slag on the basis of ensuring good initial slagging, not only can avoid the phenomenon that the slag is not well melted and does not slag after blowing is stopped too early, but also can solve the problem that the iron content in the slag is further increased due to the fact that the slag is too foamed after blowing is stopped too late, and create favorable conditions for the next operation.
Through the control of the three steps of earlier-stage slagging of the converter in the step 1), the iron content in earlier-stage slag is obviously reduced, but a large amount of metal iron beads are still contained, so that the slag can not be directly poured after the gun is stopped for blowing well in early-stage slagging, and the slag-iron separation treatment needs to be carried out on the slag.
The operation of step 2-1) aims at: firstly, observing the foaming condition of the slag; secondly, the downward precipitation of part of iron beads in the slag is promoted.
The step 2-2) is specifically as follows: when the tilting angle is 50-70 degrees, after the converter is shaken up, 100-120 Kg of iron ore is added into the converter from a high-level bin; when the tilting angle is 71-82 degrees, 50-70 Kg of iron ore is added; when the tilting angle is less than 50 degrees, after the converter is shaken up, an oxygen lance is firstly used for manually opening oxygen above the slag liquid level at the furnace mouth for slagging for 3-5 seconds, the oxygen lance descends 1-1.5 meters while opening oxygen for slagging, then the oxygen lance is closed immediately, 50-70 Kg of iron ore is added from a high-level bin, and then the operation of shaking the converter for deslagging is carried out; when the tilting angle is more than 82 degrees, the furnace is immediately shaken to the zero position, 200Kg of raw dolomite is added from a high-position storage bin, and then the operation of shaking the furnace and deslagging is carried out.
Step 2-2) principle of operation: adding iron ore according to the foaming degree of the slag, wherein the specific gravity of the iron ore is between that of steel and slag, and the iron ore has two functions: firstly, the foam slag is physically pressed; secondly, the iron ore has smaller granularity and generates violent indirect reduction reaction with the most stable CO gas in the foam slag when sinking in the foam slag, namely Fe2O3+3CO＝2Fe+3CO2Formation of CO unstable in foamed slag2A gas. The thickness of the foam slag layer can be quickly reduced under the combined action of the two, so that the downward sedimentation of iron beads in the slag is promoted, and the purpose of quickly separating slag from iron is achieved. Adding raw dolomite into the slag with weak foamability, wherein the raw dolomite has small granularity, the specific gravity of the raw dolomite is lower than that of iron ore and is between steel and slag, and the main component is CaCO3And MgCO3Generating CO by thermal decomposition in slag2On one hand, the gas plays a role in stirring in the slag layer to promote slag-iron separation, and on the other hand, the gas inflow in the slag is also increased, so that the slag with weak foamability is properly foamed under the condition of increasing the gas inflow so as to facilitate slag pouring operation.
Further, in the step 2), the following operations are adopted under the condition that the production nodes of the converter are tense and on steel grades with low requirements on nitrogen: when the oxygen gun is lifted and the oxygen is stopped, the operation of shaking the furnace to see the slag is omitted, 100Kg of iron ore is added while the blowing of the oxygen gun is stopped, the oxygen gun is manually opened to blow high-pressure nitrogen above the slag liquid level of the furnace mouth for 5 to 10 seconds, then 200Kg of raw dolomite is added from a high-level storage bin, and the operation of shaking the furnace to pour the slag is directly carried out. The operation aims to accelerate the reaction speed of the iron ore in the slag by utilizing the high-pressure nitrogen purging, and further accelerate the iron bead sedimentation in the slag by utilizing the stirring effect generated by the decomposition of the raw dolomite in the slag.
Further, in the step 3), the early-stage slag pouring amount is controlled according to 1/2-2/3 of the total slag amount in the furnace. The slag pouring amount cannot be too much or too little, and the excessive slag pouring amount can influence the next blowing, easily cause the slag to be dried back, and cause the accidents of steel sticking and the like of the oxygen lance; if the slag pouring amount is too small, the double-slag effect cannot be achieved.
Further, in the step 3), when the silicon content of the molten iron is 0.50% -0.70%, the deslagging amount is controlled according to 1/2, and when the silicon content of the molten iron is more than 0.70%, the deslagging amount is controlled according to 2/3.
The invention can obviously reduce the iron content in the slag in the early stage of the double-slag operation of the converter, reduce the metal loss and reduce the consumption of the steel and iron materials of the converter; the problem of difficulty in early deslagging is solved, and the phenomenon of early deslagging of the welding slag tank is effectively avoided; the material consumption is reduced, and the production cost is reduced; realizes the quick slag pouring of the converter, shortens the smelting period of the double-slag operation of the converter, and ensures the continuous, stable and smooth production.
Drawings
CaO-SiO at 11400 deg.C2-FeO2Viscosity of slag system;
FIG. 2CaO-SiO2-FeO2A slag system phase diagram;
FIG. 3 shows a sample with iron slag before the present invention is applied;
FIG. 4 shows no obvious iron slag sample when the present invention is used.
Detailed Description
The operational control points of the present invention will be further explained by the following examples of 120t converter smelting.
Example 1
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 1:
the balance of the ingredients in Table 1 being Fe
| C％ | Mn％ | P％ | S％ | Si％ | Ti％ | V％ | The temperature of molten iron is lower |
| 4.500 | 0.135 | 0.120％ | 0.017 | 0.613 | 0.092 | 0.043 | 1303 |
A loading system: 103t molten iron, 19.0t scrap steel and 5.6t pig iron blocks.
The specific method comprises the following steps: when the converter is continuously produced, the end-point slag after the steel is discharged from the previous converter is retained in the converter after slag splashing protection, splashing drying and solidification, the operation of retaining the whole slag is adopted, after confirmation, a 'hot metal adding and scrap steel adding' key is clicked on a main converting picture of the converter, the speed of a dust removal fan is increased to a proper position, and the operations of adding hot metal and scrap steel are carried out; molten iron and scrap steel adding operation structureTurning the converter mouth upwards to zero position in the main control chamber, clicking 'start main converting', discharging the lance for ignition, after the oxygen lance is ignited successfully, quickly lowering the lance to a low lance position with a nozzle of 1.2 m to the metal liquid level for converting, wherein the oxygen supply intensity is 3.06Nm3And/min/t, no slag is added, the early slag alkalinity of the double slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%. And blowing oxygen for 3 minutes and 40 seconds, when the CO concentration of the flue gas reaches 13 percent, lifting the lance, stopping blowing, shaking the furnace until the furnace slag in the furnace is flush with the lower edge in the deslagging side furnace mouth and the angle that the furnace slag is not poured out is 78 degrees, immediately shaking the furnace right, adding 60Kg of iron ore from a high-level stock bin, shaking the furnace down for deslagging, and adding the deslagging and the furnace shaking for 3 minutes and 30 seconds. The amount of slag poured is controlled according to 1/2 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Example 2
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 2:
the balance of the ingredients in Table 2 being Fe
A loading system: 105t molten iron +22.0t scrap steel.
When the converter is continuously produced, the end-point slag after the steel is discharged from the previous converter is retained in the converter after slag splashing protection, splashing drying and solidification, the operation of retaining the whole slag is adopted, after confirmation, a 'hot metal adding and scrap steel adding' key is clicked on a main converting picture of the converter, the speed of a dust removal fan is increased to a proper position, and the operations of adding hot metal and scrap steel are carried out; after the operation of adding molten iron and waste steel is finished, the converter mouth is upwards shaken to the zero position in the main control chamber, the 'main blowing' is started, the lower lance is used for ignition, after the oxygen lance is successfully ignited, the lance is quickly lowered to the low lance position with the nozzle being 1.2 m to the metal liquid level for blowing, and the oxygen supply intensity is 3.06Nm3And/min/t, no slag is added, the early slag alkalinity of the double slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%. Blowing oxygen for 3 minutes and 50 seconds, when the CO concentration of the flue gas reaches 15 percent, lifting the gun, stopping blowing, rocking the furnace until the furnace slag in the furnace is flush with the lower edge in the opening of the deslagging side furnace and the furnace slag is not coatedThe pouring angle is 76 degrees, the converter is immediately shaken up, 66Kg of iron ore is added from an overhead bunker, the converter is shaken down for deslagging, and the treatment time of deslagging and furnace shaking is 3 minutes and 43 seconds in total. The amount of slag poured is controlled according to 1/2 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Example 3
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 3:
the balance of the ingredients in Table 3 being Fe
| C％ | Mn％ | P％ | S％ | Si％ | Ti％ | V％ | The temperature of molten iron is lower |
| 4.750 | 0.163 | 0.118 | 0.019 | 0.892 | 0.179 | 0.063 | 1319 |
A loading system: 103t molten iron, 20.4t scrap steel and 5.3t pig iron blocks.
When the converter is continuously produced, the end-point slag after the steel is discharged from the previous converter is retained in the converter after slag splashing protection, splashing drying and solidification, the operation of retaining the whole slag is adopted, after confirmation, a 'hot metal adding and scrap steel adding' key is clicked on a main converting picture of the converter, the speed of a dust removal fan is increased to a proper position, and the operations of adding hot metal and scrap steel are carried out; after the operation of adding molten iron and waste steel is finished, the converter mouth is upwards shaken to the zero position in the main control chamber, the 'main blowing' is started, the lower lance is used for ignition, after the oxygen lance is successfully ignited, the lance is quickly lowered to the low lance position with the nozzle being 1.2 m to the metal liquid level for blowing, and the oxygen supply intensity is 3.06Nm3And/min/t, no slag is added, the early slag alkalinity of the double slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%. And blowing oxygen for 4 minutes and 30 seconds, when the CO concentration of the flue gas reaches 16%, lifting a gun, stopping blowing, shaking the furnace until the furnace slag in the furnace is flush with the lower edge in the deslagging side furnace mouth and the angle that the furnace slag is not poured out is 60 degrees, immediately shaking the furnace right, adding 108Kg of iron ore from a high-level stock bin, shaking the furnace down for deslagging, and adding the deslagging and the furnace shaking for the total treatment time of 3 minutes and 20 seconds. The amount of slag poured is controlled according to 2/3 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Example 4
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 4:
TABLE 4 balance Fe
| C％ | Mn％ | P％ | S％ | Si％ | Ti％ | V％ | The temperature of molten iron is lower |
| 4.46 | 0.153 | 0.113 | 0.020 | 0.861 | 0.069 | 0.047 | 1315 |
A loading system: 106t molten iron, 21.2t scrap steel and 2.4t slag steel.
When the converter is continuously produced, the end-point slag after the steel is discharged from the previous converter is retained in the converter after slag splashing protection, splashing drying and solidification, the operation of retaining the whole slag is adopted, after confirmation, a 'hot metal adding and scrap steel adding' key is clicked on a main converting picture of the converter, the speed of a dust removal fan is increased to a proper position, and the operations of adding hot metal and scrap steel are carried out; after the operation of adding molten iron and waste steel is finished, the converter mouth is upwards shaken to the zero position in the main control chamber, the 'main blowing' is started, the lower lance is used for ignition, after the oxygen lance is successfully ignited, the lance is quickly lowered to the low lance position with the nozzle being 1.2 m to the metal liquid level for blowing, and the oxygen supply intensity is 3.06Nm3And/min/t, no slag is added, the early slag alkalinity of the double slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%. Blowing oxygen for 4 min and 00 s, when the CO concentration of the flue gas reaches 13%, adding 100Kg of iron ore while stopping blowing by lifting the lance, manually opening high-pressure nitrogen above the slag liquid level of the furnace mouth by using the oxygen lance to purge for 5 to 10 s, and adding 200Kg of raw dolomite from a high-level storage binAnd (5) directly carrying out furnace shaking and deslagging operation on the stone. The total time of deslagging and treatment is 3 min and 00 s. The amount of slag poured is controlled according to 2/3 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Example 5
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 5:
the balance of the ingredients in Table 5 being Fe
| C％ | Mn％ | P％ | S％ | Si％ | Ti％ | V％ | The temperature of molten iron is lower |
| 4.500 | 0.214 | 0.147 | 0.021 | 0.528 | 0.062 | 0.033 | 1294 |
A loading system: 106t molten iron +22.0t scrap steel.
When the converter is continuously produced, the end-point slag after the steel is discharged from the previous converter is retained in the converter after slag splashing protection, splashing drying and solidification, the operation of retaining the whole slag is adopted, after confirmation, a 'hot metal adding and scrap steel adding' key is clicked on a main converting picture of the converter, the speed of a dust removal fan is increased to a proper position, and the operations of adding hot metal and scrap steel are carried out; after the operation of adding molten iron and waste steel is finished, the converter mouth is upwards shaken to the zero position in the main control chamber, the 'main blowing' is started, the lower lance is used for ignition, after the oxygen lance is successfully ignited, the lance is quickly lowered to the low lance position with the nozzle being 1.2 m to the metal liquid level for blowing, and the oxygen supply intensity is 3.06Nm3And/min/t, no slag is added, the early slag alkalinity of the double slag is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%. Blowing oxygen for 4 minutes and 50 seconds, when the CO concentration of flue gas reaches 15%, lifting a gun, stopping blowing and shaking the furnace, shaking the furnace until the furnace slag in the furnace is flush with the lower edge in a deslagging side furnace mouth and the angle of the furnace slag is not poured out is 48 degrees, manually opening the oxygen gun above the liquid level of the furnace mouth slag for 3-5 seconds by using the oxygen gun, lowering the oxygen gun for 1 meter while opening the oxygen gun for deslagging, immediately closing the oxygen lifting gun, adding about 50Kg of iron ore from a high-level bin, then carrying out the deslagging operation of the furnace shaking, wherein the processing time of deslagging and shaking the furnace is 3 minutes and 40 seconds in total. The amount of slag poured is controlled according to 1/2 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Example 6
A slag-iron separation method comprising the steps of:
the molten iron conditions are as follows in table 6:
the balance of the ingredients in Table 6 being Fe
| C％ | Mn％ | P％ | S％ | Si％ | Ti％ | V％ | The temperature of molten iron is lower |
| 4.600 | 0.190 | 0.126 | 0.012 | 0.570 | 0.055 | 0.040 | 1330 |
A loading system: 105t molten iron +22.7t scrap steel.
The specific method comprises the following steps: the converter is the first supplementary converter without bottom slag, a key of 'hot metal charging and scrap steel adding' is clicked on a main converting picture of the converter, and the operation of hot metal charging and scrap steel adding is directly carried out after the speed of the dust removal fan is increased to a proper position. After the operation of adding molten iron and waste steel is finished, the converter mouth is upwards shaken to the zero position in the main control chamber, the 'main blowing' is started, the lower lance is used for ignition, after the oxygen lance is successfully ignited, the lance is quickly lowered to the low lance position with the nozzle being 1.3 m to the metal liquid level for blowing, and the oxygen supply intensity is 3.06Nm3And/min/t, blowing and adding 1800Kg of lime and 800Kg of raw dolomite, wherein the alkalinity is controlled according to 1.3-1.5, and the MgO content is controlled to be less than or equal to 7.5%. Blowing oxygen for 3 min and 50 sec, when CO concentration in fume reaches 15%, lifting the gun, stopping blowing and shaking the furnace until the furnace slag is level with the lower edge of the slag pouring side furnace mouth and the angle of not pouring the furnace slag is 83 deg., immediately shaking the furnace, adding 200Kg of raw dolomite into a high-level bin, then shaking the furnace down for deslagging, adding slag and shakingThe furnace treatment time amounted to 3 minutes and 33 seconds. The amount of slag poured is controlled according to 1/2 of the total amount of slag. The main components of the slag and the amount of iron carried in the slag at the early stage of the analysis of the sampled slag are shown in Table 7.
Table 7 examples 1-6 examples of ingredients
And (3) analysis: as can be seen from the above table, CaO and MgO are controlled in a proper range, and the iron content in the slag can be effectively reduced from the original more than 20% to less than 8% through the series of slag-iron separation control.
The invention fully utilizes the existing steelmaking material conditions to achieve the purpose of quickly and efficiently separating the early-stage slag from the iron, and solves a series of production problems caused by large iron content of the early-stage slag in the double-slag operation.
Claims (6)
1. A slag-iron separation process, characterized in that it comprises the steps of:
1) earlier-stage slagging of the converter:
1-1) during continuous production of a converter, performing slag splashing protection, splashing drying and solidification on end-point slag discharged from the last converter, then keeping the end-point slag in the converter, adopting a slag-remaining operation, clicking a 'hot metal adding and scrap steel adding' key on a main converting picture of the converter after confirmation, accelerating a dust removal fan to a proper position, and performing hot metal adding and scrap steel adding operations;
1-2) finishing the operation of adding molten iron and scrap steel, shaking the converter mouth upwards to a zero position in a main control chamber, clicking to start main blowing, putting a gun down for ignition, and quickly lowering the gun to a low gun position with a nozzle reaching 1.2-1.3 m of the metal liquid level for blowing after the oxygen gun is successfully ignited, wherein the oxygen supply intensity is 3.06Nm3Min/t, the end-point slag alkalinity remained in the furnace is 2.8-3.2, the MgO content is 8-10%, and the FeO content is 15-22%;
in the step 1-2), the early-stage slag alkalinity of the double slags is controlled to be 1.3-1.5, the MgO content is less than or equal to 7.5%, and the FeO content is 9-15%;
1-3) and blowing oxygen for 3-5 minutes, wherein the concentration of CO in the flue gas reaches 10% -20%, and when the flame at the furnace mouth is obviously softened and shaken, the slag is well melted at the initial stage, and the gun is lifted and blowing is stopped;
2) separating slag from iron:
2-1), shaking the converter from the zero position to the slag pouring side in front of the converter to an angle that the slag in the converter is flush with the lower edge of the inner edge of the slag pouring side furnace mouth and the slag is not poured out, stopping shaking the converter, wherein the tilting angle reflects the height condition of the slag liquid level in the converter, and then shaking the converter upwards to the zero position with the furnace mouth upwards;
2-2) determining a specific treatment method according to the height condition of the liquid level of the slag in the furnace reflected by the tilting angle:
when the tilting angle is 50-70 degrees, after the converter is shaken up, 100-120 Kg of iron ore is added into the converter from a high-level bin; when the tilting angle is 71-82 degrees, 50-70 Kg of iron ore is added; when the tilting angle is less than 50 degrees, after the converter is shaken up, an oxygen lance is firstly used for manually opening oxygen above the slag liquid level at the furnace mouth for slagging for 3-5 seconds, the oxygen lance descends 1-1.5 meters while opening oxygen for slagging, then the oxygen lance is closed immediately, 50-70 Kg of iron ore is added from a high-level bin, and then the operation of shaking the converter for deslagging is carried out; when the tilting angle is more than 82 degrees, immediately shaking the furnace to a zero position, adding 200Kg of raw dolomite from a high-position storage bin, and then carrying out furnace shaking and deslagging operation;
3) and early-stage slag pouring amount control:
the early-stage slag pouring amount is controlled according to 1/2-2/3 of the total slag amount in the furnace;
further, in the step 1-1), if the first furnace is produced after furnace repairing or maintenance, bottom slag does not exist in the furnace, and molten iron and scrap steel adding operation is directly carried out after the dedusting fan is accelerated to be in place.
2. The method as claimed in claim 1, wherein in the step 1-1), if the first furnace is produced after the furnace is repaired or overhauled, no bottom slag is in the furnace, and the operations of adding molten iron and scrap steel are directly carried out after the dedusting fan is accelerated in place.
3. The method according to claim 1, wherein in the step 1-2), the initial slag is produced by blowing without adding any slag, and the bottom slag remained in the furnace is fully utilized.
4. The method according to claim 1, wherein in step 1-2), the average basicity is 1.43, the MgO content is on average 5.1%, and the FeO content is 13.8%.
5. The method according to claim 1, wherein in the step 1-2), the first furnace is produced after furnace repairing or maintenance, no bottom slag exists in the furnace, slag charge is required to be added for slagging when the converter is started to blow, the alkalinity is controlled according to 1.3-1.5, and the MgO content is controlled to be less than or equal to 7.5%.
6. The method according to claim 1, characterized in that in step 2) the following operations are applied in the case of a tight converter production node and on steel grades with less stringent nitrogen requirements: when the oxygen gun is lifted and the oxygen is stopped, the operation of shaking the furnace to see the slag is omitted, 100Kg of iron ore is added while the blowing of the oxygen gun is stopped, the oxygen gun is manually opened to blow high-pressure nitrogen above the slag liquid level of the furnace mouth for 5 to 10 seconds, then 200Kg of raw dolomite is added from a high-level storage bin, and the operation of shaking the furnace to pour the slag is directly carried out.
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| CN101189349B (en) * | 2005-05-13 | 2010-09-22 | 技术资源有限公司 | Cold start-up method for a direct smelting process |
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