CN114941049B - Converter bottom control method - Google Patents
Converter bottom control method Download PDFInfo
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- CN114941049B CN114941049B CN202210588496.3A CN202210588496A CN114941049B CN 114941049 B CN114941049 B CN 114941049B CN 202210588496 A CN202210588496 A CN 202210588496A CN 114941049 B CN114941049 B CN 114941049B
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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
- C21C5/42—Constructional features of converters
- C21C5/44—Refractory linings
- C21C5/441—Equipment used for making or repairing linings
- C21C5/443—Hot fettling; Flame gunning
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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
Abstract
The invention belongs to the field of converter steelmaking, and particularly relates to a converter bottom control method, which comprises the following steps: s1, after tapping, swinging the converter forwards until the inclination angle is 90 degrees, measuring the total iron content and the furnace bottom height in the red slag, and pouring out part of the red slag; s2, shaking the converter to a zero position, selecting a slag concentration regulator according to the height of the furnace bottom measured in the step S1, adding the slag concentration regulator into the converter according to the total iron content, and spreading; s3, blowing nitrogen to splash slag, so that the slag is cooled and condensed at the bottom of the furnace; s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished; s5, repeating the step S1, and if the furnace bottom height does not accord with the expected value, performing the step S2-the step S4 to adjust the furnace bottom height until the furnace bottom height accords with the expected value. The invention ensures that the height of the furnace bottom is kept within the range of expected values by adjusting the viscosity of the slag, thereby being beneficial to saving the cost and ensuring the quality of molten steel.
Description
Technical Field
The invention belongs to the field of converter steelmaking, and particularly relates to a converter bottom control method.
Background
The height of the converter bottom is the distance between the bottom furnace lining and the water tank at the furnace mouth after the new furnace lining is built, is an important index of the converter, and has important significance for maintaining the furnace type of the converter and controlling the smelting process. The furnace bottom is too low, the furnace lining at the furnace bottom position is thinner, and molten steel is easy to penetrate the furnace bottom to cause furnace leakage; the furnace bottom is too high, the molten steel reaction position in the furnace is wholly moved upwards, the furnace capacity ratio of the converter is reduced, splashing is easily caused, steel material consumption and other indexes are affected, meanwhile, the molten steel reaction position is wholly moved upwards, so that the erosion effect of high-temperature molten steel and slag on the trunnion furnace cap position is enhanced, the whole service life of a furnace lining is shortened, and the steelmaking cost is increased.
At present, most of the converter steelmaking of the domestic steel factory adopts a top-bottom combined blowing converter, and the combined blowing method utilizes bottom blowing air flow to overcome the defect of insufficient stirring capability of top blowing oxygen flow to a molten pool, so that the reaction in the converter is close to balance, iron loss is reduced, and meanwhile, the advantage that the slag forming process is easy to control by the top blowing method is maintained, so that the method has better technical and economic indexes than top blowing and bottom blowing.
When the molten steel temperature is higher, the carbon low-oxidization property is strong and the slag alkalinity is low continuously at the end point of the converter, the corrosion of the slag splashing layer at the bottom of the converter aggravates the easy reduction of the bottom of the converter, and otherwise, the bottom of the converter is easy to rise. If the furnace bottom is too high, bottom blowing gas is more difficult to penetrate through the furnace bottom, the stirring effect on molten steel is weakened, the oxidizing property of the molten steel is enhanced, molten steel inclusions are correspondingly increased, and the quality of casting blanks is reduced; if the furnace bottom is too low, the furnace lining bricks reduce the furnace age of the converter, which is very easy to cause malignant accidents such as furnace leakage and the like, and the production stability and the equipment safety are endangered. The reasonable furnace bottom height can further strengthen the stirring of a molten pool, promote the control stability of the smelting process, reduce the total iron of slag and improve the quality of molten steel.
In the existing maintenance process for the converter bottom, most of the existing maintenance process for the converter bottom can only use slag adjusting agents to fill the corroded part of the converter bottom, for example, chinese patent document CN 107460271A (application number 201710552189.9) discloses a method for maintaining the converter bottom, 30% -50% of slag is poured out after tapping of a converter, an oxygen lance nitrogen seal is opened, the addition amount of dolomite is determined according to the end point oxygen of the converter and the slag amount of the slag, the converter is carried out, the converter is still sintered after the carrying of the converter is completed, and then high-pressure nitrogen is used for splashing the converter to form a slag layer so as to improve the converter bottom height. However, in this method, only the furnace bottom height is increased, and the problem that the furnace bottom height needs to be reduced cannot be effectively solved. Meanwhile, the amount of the poured slag and the amount of the added raw dolomite in the method are controlled according to the smelting mode, and cannot be well matched with the slag state, so that the effect of adjusting the furnace bottom height is not ideal. Therefore, how to determine the slag pouring amount and the slag modifier adding amount according to the slag state at the end point is a key problem for adjusting the furnace bottom height.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a converter bottom control method, which aims at the end point state and the converter bottom height, adds slag concentration regulators with different types and qualities, timely adjusts the converter bottom height, promotes the control stability of the smelting process and improves the quality of molten steel.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a converter hearth control method comprising the steps of:
s1, after tapping, swinging the converter forwards until the inclination angle is 90 degrees, measuring the total iron content (FeO content) in the final red slag, measuring the height of the bottom of the converter, swinging the converter forwards, and pouring out red slag according to the total iron content in the red slag;
s2, shaking the converter to a zero position, judging the type of the slag concentration regulator to be added according to the height of the furnace bottom measured in the step S1, adding the slag concentration regulator with corresponding mass into the converter according to the total iron content, and spreading;
s3, blowing nitrogen to splash slag, cooling and condensing the slag at the bottom of the furnace, and gradually lowering the gun position according to the slag splashing condition until the slag splashing is finished;
s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished;
s5, repeating the step S1, and if the furnace bottom height does not accord with the expected value, performing the step S2-the step S4 to adjust the furnace bottom height until the furnace bottom height accords with the expected value.
Preferably, in the step S1, the pouring amount of the red slag in the furnace is 1/2 to 2/3 of the total volume of the red slag at the end point, and specifically, when the FeO content in the slag is less than or equal to 14%, the red slag is poured out by 1/2 of the total volume; when the FeO content in the slag is more than or equal to 20%, pouring out 2/3 of the total volume of the red slag; when the FeO content in the slag is between 14 and 20 percent, the pouring amount of the red slag is increased from 1/2 to 2/3 along with the FeO content.
The slag splashing furnace protection technology is to utilize the steelmaking end slag with saturated or supersaturated MgO content, and through high pressure splashing, cool and solidify to form a slag layer with high melting point on the surface of the furnace lining, and adhere to the furnace lining, as introduced in the prior art in the background technology, only the thickness or the furnace bottom height of the furnace lining can be improved. The purpose of the nitrogen blowing is to provide power for slag splashing and in addition it has the effect of cooling the slag. The cooling slag is generally mainly in the first 2min of nitrogen blowing, because the slag is still thin during this time and is not well attached even if splashed onto the furnace wall. When nitrogen is blown for more than 2 minutes, the slag begins to be splashed largely and can be splashed to the furnace cap. The invention combines the slag splashing protection to regulate the converter bottom, focuses on regulating the converter bottom, and still can achieve the best effect only by regulating the slag splashing protection process.
According to the invention, the amount of the poured red slag is controlled according to the total iron content so as to match with the subsequently added slag concentration regulator to effectively regulate the slag concentration, if the slag is poured less (less than 1/2), the cooling time of the slag is long, the coagulation effect of the slag concentration regulator is poor, the added slag concentration regulator can not effectively regulate the slag concentration, and thus the repaired furnace bottom is damaged in the smelting process, so that the regulation is idle work, the smelting quality can not be ensured while the manpower and material resources are wasted, and even the risk of accidents exists; if the slag is excessively poured (more than 2/3), the slag concentration regulator added later and a small amount of residual slag are quickly cooled and condensed, and cannot be well and uniformly spread on the furnace bottom, so that the furnace bottom height regulating effect cannot be effectively ensured.
Preferably, in the step S1, the method of measuring the furnace bottom may use a measuring furnace bottom shovel, a laser range finder, or other more reliable methods.
Preferably, the addition amount of the slag concentration regulator in the step S2 increases as the total iron content in the terminal slag increases; further preferably, when the tonnage of the converter is 120T and the FeO content is lower than 15%, the adding amount of the slag concentration regulator is controlled to be 500-800 kg; when the FeO content is between 15 and 20 percent, the adding amount of the slag concentration regulator is controlled between 800 and 1200kg; when the FeO content is higher than 20%, controlling the adding amount of the slag concentration regulator to be 1200-1500 kg; when the tonnage of the converter is another value, the addition amount of the slag concentration adjusting agent=the addition amount mentioned above is x (ton of converter/120T).
And (2) on the basis of pouring out the slag according to the total iron content in the step (S1), controlling the addition amount of the slag concentration regulator according to the total iron content, and when the numerical value of the height of the furnace bottom needs to be increased or reduced is large, carrying out multi-furnace-number regulation, wherein if excessive regulator is added at one time, a large amount of slag is accumulated on the furnace bottom to influence the sintering effect, and the material collapse easily occurs in the furnace shaking process.
The total iron content (namely FeO content) in the slag has great influence on the slag splashing effect. The mineral composition of FeO in slag is mostly various low-melting-point ferrite, the melting point is far lower than the tapping temperature, and the higher the FeO content is, the more ferrite is, so that the higher the slag fluidity is, the erosion effect on a furnace lining is increased, the FeO is not easy to adhere to the furnace lining, and the adjustment of the furnace bottom height is not facilitated. The higher the FeO content is, the proper reduction of the slag amount in the furnace is realized, and the more slag concentration regulator is added, so that the slag fluidity can be adjusted more effectively. The slag splashing time is generally comprehensively considered according to factors such as the tonnage of the furnace, the air supply quantity, the slag quantity in the furnace, the slag condition, the production rhythm and the like, and the nitrogen blowing time of each steel mill in China is generally 3-5 min. The long slag splashing time can influence the production rhythm and cause the waste of energy media. The slag remaining amount is adjusted according to the total iron content, the addition amount of a furnace time regulator with small slag remaining amount is increased, the slag amount in the furnace can be kept in a proper constant range, and the slag splashing effect is ensured.
Preferably, in the step S2, the slag concentration regulator includes a magnesium thickener and a calcium diluent; it is further preferred that the magnesium thickener is added when the hearth is lower and needs to be raised and the calcium diluent is added when the hearth is higher and needs to be lowered.
Preferably, the magnesium thickener is dolomite, and the calcium diluent is limestone.
Preferably, in the step S2, in order to save time, the slag concentration regulator is weighed in advance and added into the converter by using a top bin of the converter.
Preferably, in the step S2, the spreading is performed by shaking the furnace before and after, and then reducing the lance position of the oxygen lance to blow nitrogen; further preferably, the front and back shaking is performed at least three times, one shaking comprises forward shaking and backward shaking, and the inclination angle of the converter is 40 degrees when the front and back shaking is performed; the method specifically comprises the steps of reducing the position of the oxygen lance to 1.0m, blowing nitrogen into the furnace, uniformly spreading the slag concentration regulator on the bottom of the furnace, controlling the pressure of the nitrogen to 1.2-1.6 MPa, and controlling the time to 25-35 s.
Preferably, in the step S3, when the nitrogen is blown to splash slag, the slag splashing gun is 3.0m, the nitrogen gas is turned on for 45-60S, the nitrogen gas pressure is controlled to be 1.2-1.6 MPa, further preferably, the nitrogen gas is turned on for 55S, and the nitrogen gas pressure is controlled to be 1.5MPa.
Preferably, the slag splashing gun position is reduced by 0.5m every 30 s; the slag splashing situation observed by the furnace mouth can be properly regulated, and when the slag splashing is severe, the speed of the slag splashing gun is reduced; when the splashing slag is gentle, the speed of the splashing slag gun is increased.
Preferably, in the step S3, the lowest position of the slag splashing gun is not lower than 0.8m.
The beneficial effects of the invention are as follows:
according to the invention, in the process of splashing slag of the converter, part of red slag is poured out according to the total iron content of the end-point red slag, then, a corresponding slag concentration regulator is added according to the difference between the height of the converter bottom and an expected value, a magnesium thickener is added when the converter bottom is lower, a calcium diluent is added when the converter bottom is higher, the addition amount of the slag concentration regulator is determined according to the total iron content, slag splashing operation is carried out after the slag concentration regulator spreads at the converter bottom, mgO (or CaO) generated after the decomposition of the added slag concentration regulator participates in the reaction in the converter, and the viscosity of the slag is regulated, so that the height of the converter bottom is kept within the range of the expected value, the cost is saved, and the quality of molten steel is ensured.
Detailed Description
The invention is described in detail below with reference to examples:
example 1:
in this example, a 120T converter (hearth height, i.e., hearth-to-hearth distance, control requirement 7.55-7.75 m) is taken as an example.
The converter bottom control method specifically comprises the following steps:
s1, after tapping, the converter is rocked forwards to 90 degrees, a laser range finder is used for measuring the bottom of the converter, the distance from the bottom of the converter to a furnace mouth is 7.40m, the distance is higher than the minimum control requirement, and the state of red slag in the converter is as follows: feO content is 14%, so that 1/2 of red slag in the furnace is poured out;
s2, according to the measured furnace bottom height, the difference between the measured furnace bottom height and the lowest value of 7.55m is 0.15m, and the FeO content condition in the red slag is combined, so 600kg of limestone is selected to be added into the furnace through a top bin, the furnace is rocked for three times before and after, the furnace rocking angle is 40 degrees each time, and the limestone is spread on the furnace bottom; reducing an oxygen gun, blowing high-pressure nitrogen into the furnace, controlling the pressure of the nitrogen to be 1.6MPa, keeping the gun position to be 1.0m, controlling the time to be 25s, and uniformly spreading limestone on the bottom of the furnace;
s3, raising the slag splashing gun position to 3.0m, blowing nitrogen for 45s, gradually lowering the gun position according to the slag splashing condition, wherein the gun position is lowered by 0.5m every 30s, and the lowest gun position is not lower than 0.8m until the slag splashing is finished;
s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished;
s6, after converting is finished, the step S1 is repeated to measure the height of the furnace bottom, the distance from the furnace bottom to the furnace mouth is found to be 7.49m, the expected value is found to be still not met, the steps S2-S4 are repeated again, and the height of the furnace bottom is 7.55m after three continuous times, so that the requirements are met.
According to the control method, lime (CaO) is generated by decomposing limestone at the bottom of the furnace, and a large amount of carbon dioxide gas is generated in the decomposition process, so that the stirring effect of the bottom of the furnace is enhanced. Meanwhile, the lime prevents the slag from being adhered to the furnace bottom, the thickness of the slag adhered to the furnace bottom is reduced, and the slag layer at the furnace bottom is further thinned and the furnace bottom is lowered due to high-temperature scouring and oxidation erosion of molten steel in the blowing process, so that the distance from the furnace bottom to the furnace mouth is reduced from 7.40m to 7.55m.
Example 2:
in this example, a 120T converter (hearth height, i.e., hearth-to-hearth distance, control requirement 7.55-7.75 m) is taken as an example.
The converter bottom control method specifically comprises the following steps:
after S1 tapping is finished, the converter is rocked forward to 90 degrees, a laser range finder is used for measuring the bottom of the converter, the distance between the bottom of the converter and a furnace mouth is 7.85m, and the state of red slag in the converter is as follows: feO content is 20%, so red slag in the furnace is poured out for 2/3;
s2, according to the measured furnace bottom height, the difference between the measured furnace bottom height and the highest value of 7.75m is 0.1m, and the FeO content condition in red slag is combined, 1200kg of raw dolomite is selected to be added into the furnace through a top feed bin, the furnace is rocked for three times before and after, the furnace rocking angle is 40 degrees each time, and the raw dolomite is spread on the furnace bottom; reducing an oxygen gun, blowing high-pressure nitrogen into the furnace, controlling the pressure of the nitrogen to be 1.2MPa, keeping the gun position to be 1.0m, controlling the time to be 35s, and uniformly spreading the raw dolomite at the bottom of the furnace;
s3, raising the slag splashing gun position to 3.0m, blowing nitrogen for 60s, gradually lowering the gun position according to the slag splashing condition, wherein the gun position is lowered by 0.5m every 30s, and the lowest gun position is not lower than 0.8m until the slag splashing is finished;
s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished;
and S5, after converting is finished, the step S1 is repeated to measure the height of the furnace bottom, the distance from the furnace bottom to the furnace mouth is found to be 7.77m, the expected value is not met, the steps S2-S4 are repeated again, and the furnace bottom is measured for 7.70m after three continuous times, so that the requirements are met.
According to the control method, the raw dolomite is decomposed to generate magnesium oxide (MgO) at the furnace bottom, the content of high-melting-point substances in slag is increased, the viscosity of the slag is increased, the slag is accumulated at the furnace bottom, and the furnace bottom is lifted, namely, the distance from the furnace bottom to the furnace mouth is lifted to 7.70m from 7.85 m.
Example 3:
in this example, a 120T converter (hearth height, i.e., hearth-to-hearth distance, control requirement 7.55-7.75 m) is taken as an example.
The converter bottom control method specifically comprises the following steps:
after S1 tapping is finished, the converter is rocked forward to 90 degrees, a laser range finder is used for measuring the bottom of the converter, the distance between the bottom of the converter and a furnace mouth is 7.82m, and the state of red slag in the converter is as follows: feO content is 16%, so red slag in the furnace is poured out for 3/5;
s2, according to the measured furnace bottom height, the difference between the measured furnace bottom height and the highest value of 7.75m is 0.07m, and in combination with the FeO content condition in the red slag, 900kg of raw dolomite is selected to be added into the furnace through a top feed bin, the furnace is rocked for three times before and after, the furnace rocking angle is 40 degrees each time, and the raw dolomite is spread on the furnace bottom; reducing an oxygen gun, blowing high-pressure nitrogen into the furnace, controlling the pressure of the nitrogen to be 1.4MPa, keeping the gun position to be 1.0m, controlling the time to be 30s, and uniformly spreading the raw dolomite at the bottom of the furnace;
s3, raising the slag splashing gun position to 3.0m, blowing nitrogen for 55s, gradually lowering the gun position according to the slag splashing condition, wherein the gun position is lowered by 0.5m every 30s, and the lowest gun position is not lower than 0.8m until the slag splashing is finished;
s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished;
and S5, after converting is finished, the step S1 is repeated to measure the height of the furnace bottom, the distance from the furnace bottom to the furnace mouth is found to be 7.79m, the expected value is not met, the steps S2-S4 are repeated again, and the furnace bottom is measured for 7.71m after three continuous times, so that the requirements are met.
According to the control method, the raw dolomite is decomposed to generate magnesium oxide (MgO) at the furnace bottom, the temperature of slag is reduced, the content of high-melting-point substances in slag is increased, the viscosity of slag is increased, slag is accumulated at the furnace bottom, and the furnace bottom is lifted, namely the distance from the furnace bottom to a furnace mouth is lifted to 7.71m from 7.82 m.
Comparative example 1
In this comparative example, two sets of comparative experiments were set, comparative experiment A and comparative experiment B, and the experimental conditions and experimental procedures of the two sets of comparative experiments were exactly the same as those of example 1, except that comparative experiment A poured out red slag accounting for 1/3 of the total volume and comparative experiment B poured out red slag accounting for 4/5 of the total volume in step S1.
After steps S2-S4 are continuously carried out for three times, the furnace bottom heights of two groups of comparison experiments are measured, the distance from the furnace bottom to the furnace mouth in the comparison experiment A is found to be 7.42m, the distance from the furnace bottom to the furnace mouth in the comparison experiment B is found to be 7.38m, and the distance from the furnace bottom to the furnace mouth in the comparison experiment B cannot reach the expected value of the furnace bottom height, which is the reason that when red slag is excessively poured out in the comparison experiment A, the red slag cannot reach the expected value is too much, the red slag is cooled for a long time, has larger fluidity, cannot be sintered effectively at the furnace bottom, the slag splashing time is long in the nitrogen blowing process, and the furnace bottom is raised due to accumulation of slag at the furnace bottom position; in the comparative experiment B, when the red slag is excessively poured, the reason that the expected value cannot be reached is that the slag fluidity is poor after the regulator is added, the slag splashing time is short, and the sintering effect at the bottom of the furnace is poor. Therefore, the method and the device control the pouring amount of the red slag according to the pertinence of the total iron content, optimize the effect of adjusting the furnace bottom height, and realize the technical effect which cannot be expected by the person skilled in the art.
Comparative example 2
In this comparative example, two sets of comparative experiments were set, comparative experiment C and comparative experiment D, and the experimental conditions and experimental procedures of the two sets of comparative experiments were exactly the same as those of example 2, except that 600kg of raw dolomite was added to comparative experiment C and 3000kg of raw dolomite was added to comparative experiment D in step S2.
After three consecutive runs of steps S2-S4, two sets of comparative experiments were performed, and the hearth-to-hearth distance in comparative experiment C was found to be 7.78m, and the hearth-to-hearth distance in comparative experiment D was found to be 7.82m, both of which failed to reach the expected hearth height. In the comparison experiment C, when the added raw dolomite is too small, the reason that the expected value cannot be reached is that the slag is not cooled rapidly, the slag still has certain fluidity after slag splashing, and the slag is washed out and falls off when the shaking furnace is used for charging iron, so that the furnace bottom height cannot be increased; in the comparative experiment D, when the added raw dolomite is too much, the reason that the expected value cannot be reached is that the temperature is reduced too fast, the sintering effect is poor, pits are generated by the furnace bottom collapse in the furnace shaking process, and therefore the effect of improving the furnace bottom height is also affected. Therefore, the method and the device for adjusting the slag concentration of the furnace bottom of the furnace control the addition amount of the slag concentration regulator according to the total iron content, optimize the effect of adjusting the height of the furnace bottom and realize the technical effect which cannot be expected by the person skilled in the art.
Unless otherwise specified, the present invention is not limited to the above-described embodiments, and is not limited to the above-described embodiments.
There are, of course, many embodiments of the invention that can be varied and modified from the teachings of this invention by those skilled in the art, and that such variations and modifications are within the scope of the appended claims without departing from the spirit and the substance of the invention.
Claims (6)
1. The converter bottom control method is characterized by comprising the following steps:
s1, after tapping, swinging the converter forwards until the inclination angle is 90 degrees, measuring the total iron content in the end-point red slag, measuring the height of the bottom of the converter, swinging the converter forwards, and pouring out the red slag according to the total iron content in the red slag;
s2, shaking the converter to a zero position, judging the type of the slag concentration regulator to be added according to the height of the furnace bottom measured in the step S1, adding the slag concentration regulator with corresponding mass into the converter according to the total iron content, and spreading;
s3, blowing nitrogen to splash slag, cooling and condensing the slag at the bottom of the furnace, and gradually lowering the gun position according to the slag splashing condition until the slag splashing is finished;
s4, adding scrap steel according to normal production requirements after slag splashing is finished, and adding molten iron for converting until converting is finished;
s5, repeating the step S1, and if the furnace bottom height does not accord with the expected value, performing the step S2-the step S4 to adjust the furnace bottom height until the furnace bottom height accords with the expected value;
in the step S1, according to the condition of the end-point slag, pouring out 1/2 to 2/3 of red slag in the furnace, and when the FeO content in the slag is less than or equal to 14 percent, pouring out 1/2 of red slag; when the FeO content in the slag is more than or equal to 20%, pouring out 2/3 of red slag; when the content of FeO in the slag is 14% -20%, the pouring amount of the red slag is gradually increased from 1/2 to 2/3 along with the increase of the content of FeO;
the addition amount of the slag concentration regulator in the step S2 is increased along with the increase of the total iron content in the terminal slag; when the tonnage of the converter is 120T and the FeO content is lower than 15%, controlling the adding amount of the slag concentration regulator to be 500-800 kg; when the FeO content is between 15 and 20 percent, the adding amount of the slag concentration regulator is controlled between 800 and 1200kg; when the FeO content is higher than 20%, controlling the adding amount of the slag concentration regulator to be 1200-1500 kg; when the tonnage of the converter is another value, the addition amount of the slag concentration adjusting agent=the addition amount mentioned above is x (converter tonnage/120T);
in the step S2, the slag concentration regulator comprises a magnesium thickener and a calcium diluent, wherein the magnesium thickener is added when the furnace bottom is lower and needs to be improved, and the calcium diluent is added when the furnace bottom is higher and needs to be reduced; the magnesium thickener is dolomite, and the calcium diluent is limestone.
2. The converter bottom control method according to claim 1, wherein in the step S2, the spreading is performed by shaking the converter before and after, and then nitrogen blowing is performed by lowering the lance position of the lance; the front and back shaking is carried out for at least three times, one shaking comprises forward shaking and backward shaking, and the inclination angle of the converter is 40 degrees when the front and back shaking is carried out; the method specifically comprises the steps of reducing the position of the oxygen lance to 1.0m, blowing nitrogen into the furnace, uniformly spreading the slag concentration regulator on the bottom of the furnace, controlling the pressure of the nitrogen to 1.2-1.6 MPa, and controlling the time to 25-35 s.
3. The control method of converter bottom according to claim 1, wherein in the step S3, when the nitrogen is blown to splash slag, the slag splashing gun position is 3.0m, the nitrogen opening time is 45-60S, and the nitrogen pressure is controlled to be 1.2-1.6 MPa.
4. The method for controlling the bottom of a converter according to claim 3, wherein in the step S3, when the slag is blown with nitrogen, the nitrogen is turned on for 55 seconds, and the nitrogen pressure is controlled to be 1.5MPa.
5. The converter bottom control method according to claim 3, wherein in the step S3, the slag splashing gun position is lowered by 0.5m every 30S; when the splashing slag is severe, the speed of lowering the splashing slag gun position is reduced; when the splashing slag is gentle, the speed of the splashing slag gun is increased.
6. The converter bottom control method according to claim 5, wherein in the step S3, a lowest slag splashing lance position is not lower than 0.8m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210588496.3A CN114941049B (en) | 2022-05-26 | 2022-05-26 | Converter bottom control method |
Applications Claiming Priority (1)
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