CN113046513B - Method for eliminating partial splashing phenomenon in slag splashing furnace protection process - Google Patents
Method for eliminating partial splashing phenomenon in slag splashing furnace protection process Download PDFInfo
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- CN113046513B CN113046513B CN202110278966.1A CN202110278966A CN113046513B CN 113046513 B CN113046513 B CN 113046513B CN 202110278966 A CN202110278966 A CN 202110278966A CN 113046513 B CN113046513 B CN 113046513B
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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
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
The invention discloses a method for eliminating the phenomenon of partial splashing in the slag splashing furnace protection process, and belongs to the technical field of converter steelmaking. The invention obtains the reason of the partial splashing and the harm caused by the partial splashing by adding raw dolomite in the process of slag splashing protection by analyzing the partial splashing phenomenon generated by adding the raw dolomite in the process of slag splashing protection, carries out temperature measurement sampling when the smelting of a converter reaches the end point, adds the raw dolomite, carries out the tapping operation of the converter, and carries out the slag splashing protection operation after the tapping is finished, wherein, the influence on the slag splashing protection caused by the incrustation and lump formation of the slag is reduced by carrying out quantitative control on the addition of the raw dolomite and optimizing the addition time of the raw dolomite, thereby reducing the influence on the superheat degree of the slag due to the uncertain factors of the addition amount, reducing the influence on the slag splashing protection caused by the incrustation and lump formation of the slag, and obtaining the relation between the grain size of the raw dolomite and the furnace entering included angle by controlling the raw dolomite in the falling point area of the converter, strictly controlling the grain size of the furnace entering of the raw dolomite, and eliminating the generation of the partial splashing phenomenon, thereby achieving the purpose of high-efficiency slag splashing.
Description
Technical Field
The invention relates to the technical field of converter steelmaking, in particular to a method for eliminating the phenomenon of partial splashing in the slag splashing furnace protection process.
Background
At present, slag splashing furnace protection operation is generally adopted in various large steel mills to maintain a furnace body, and high-temperature end slag with relatively proper alkalinity making and magnesium oxide is utilized to be uniformly adhered to the surface of a furnace lining under the blowing and splashing action of high-pressure nitrogen and well combined with the furnace lining to form a compact slag splashing protection layer, so that the scouring of molten steel, furnace slag and other factors in the blowing process is reduced, the furnace lining is protected, and the service life of a converter is prolonged. Aiming at the current fast-paced steelmaking mode, most steel mills add raw dolomite when adopting slag splashing, and rapidly cool and solidify slag to achieve the purpose of shortening the slag splashing time. At present, most steel mills generally adopt the slag splashing process to add a modifier or raw dolomite for slag regulation treatment when facing special conditions of low carbon content of molten steel, high oxygen activity of the molten steel and steel slag, high tapping temperature and the like at the smelting end point so as to achieve the purpose of efficient slag splashing furnace protection. However, the problems of temperature drop, slag wrapping, caking and the like caused by the addition of raw dolomite are generally ignored, so that influences such as obstruction, inhibition and the like on slag splashing dynamics in the furnace are generated, further, a splashing phenomenon is caused, the uniformity of the splashed slag is caused, and great influences are generated on furnace type maintenance and control.
The phenomenon of partial splashing in the slag splashing furnace protection process is defined as follows: in the slag splashing furnace protection process, the temperature of the furnace slag is reduced too fast due to the addition of the modifier or the raw dolomite, and the phenomena of caking and lump wrapping of the surface of the furnace slag occur; or due to the adoption of single-side feeding of the high-level bunker, the feeding nonuniformity is caused, and the materials are piled up on the surface of the slag; the slag splashing dynamics in the furnace is deteriorated and disordered due to the two main factors, so that the slag splashing effects of the trunnions at the two sides are greatly different, and the furnace type control is greatly influenced, which is called as follows: the phenomenon of partial splashing in the slag splashing furnace protection process (shown in figure 1). How to solve the problem of partial splashing caused by adding a modifier or raw dolomite in the slag splashing furnace protection process, thereby stably and effectively controlling the furnace type of the converter is an urgent technical problem to be solved.
Disclosure of Invention
1. Technical problem to be solved by the invention
Aiming at the problem that the converter splashing phenomenon is caused by adding a modifier or raw dolomite in the slag splashing furnace protection process, how to stably and effectively control the converter type is an urgent technical problem to be solved, the method for eliminating the slag splashing phenomenon in the slag splashing furnace protection process is provided, the generation of the slag splashing furnace protection process is eliminated by means of quantitative control of adding the raw dolomite, optimization of the adding time of the raw dolomite, reasonable control of the particle size of the raw dolomite, the relation of furnace entering included angles and the like, and the slag splashing furnace protection effect and the control of the furnace type are improved.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a method for eliminating the phenomenon of partial splashing in the slag splashing furnace protecting process is characterized in that: when the smelting of the converter reaches the end point, temperature measurement sampling is carried out, raw dolomite is added, the tapping operation of the converter is carried out, and slag splashing furnace protection operation is carried out after the tapping operation is finished;
controlling the addition amount of the raw dolomite by controlling the relation between the melting point of the slag and the tapping temperature, wherein the tapping temperature is T, and the melting point of the slag is T;
when T-T is more than 15 ℃, the addition amount of raw dolomite is as follows: m ═ T × 7.69 kg;
when T-T is less than or equal to 15 ℃, raw dolomite is not added.
In order to increase the reaction and mixing time of the raw dolomite and the slag, fully play the role of the raw dolomite, optimize the furnace entering time of the raw dolomite, quantitatively control the addition of the raw dolomite by reasonably controlling the relationship between the melting point of the slag and the tapping temperature, increase the mixing reaction time of the raw dolomite and the slag, eliminate the negative effect of furnace slag incrustation caused by the addition of the raw dolomite, accelerate cooling and shorten the slag splashing furnace protection time.
According to a further technical scheme, the raw dolomite is subjected to vibration type feeding through vibration equipment.
According to a further technical scheme, the relation between the grain size of raw dolomite and a furnace-entering included angle is as follows:
wherein d is the diameter of dolomite; k is a constant and takes a value of 30; rho is the density of dolomite; v is the furnace entering speed; theta is a furnace entrance included angle; eta is air viscosity coefficient of 1.82 × 10-5Pa · s; g acceleration of gravity of 9.8m/s2(ii) a x is the horizontal distance from the falling point to the starting point; Δ x is interval variation, and Δ x is more than or equal to 0 and less than or equal to 0.85 m; H. r is the inner height of the converter and the radius of a molten pool respectively; h is the vertical distance from the hopper to the furnace mouth.
The falling point area of the raw dolomite in the converter is controlled to obtain the relation between the grain size of the raw dolomite and the included angle of the raw dolomite entering the converter, the grain size of the raw dolomite entering the converter is strictly controlled, and the influence on slag splashing dynamics caused by lump accumulation is reduced.
In a further technical scheme, the density rho of the raw dolomite is 3.0 multiplied by 103kg/m3。
According to a further technical scheme, the furnace entering included angle theta is (0, pi/2).
In a further technical scheme, the variation of Δ x is as follows: and deltax is more than or equal to 0 and less than or equal to 0.85 m.
According to a further technical scheme, the vertical distance h from the hopper to the furnace mouth is 10-15 m.
According to a further technical scheme, the height H in the converter and the radius R of a molten pool are respectively 6.2m and 2.3 m.
And (3) substituting the data into a relational expression between the particle size of the raw dolomite and the furnace-entering included angle to obtain the horizontal distance x from the falling point to the starting point, thereby calculating the particle size of the adopted raw dolomite.
The invention eliminates the generation of the partial splashing in the slag splashing furnace protection process by adopting the modes of quantitative control of adding the raw dolomite, optimizing the adding time of the raw dolomite, reasonably controlling the relationship between the granularity of the raw dolomite and the furnace entering included angle and the like, and improves the slag splashing furnace protection effect and the furnace type control.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) according to the method for eliminating the partial splashing phenomenon in the slag splashing furnace protection process, the quantitative control is performed on the addition of the raw dolomite, so that the great influence on the superheat degree of the slag due to the uncertain factors of the addition amount is reduced; and by optimizing the addition time of the raw dolomite, the uniform mixing and reaction time of the raw dolomite and the furnace slag can be increased, and the influence on slag splashing furnace protection caused by furnace slag incrustation and lump formation can be reduced.
(2) According to the method for eliminating the partial splashing phenomenon in the slag splashing protection process, the relation between the grain size of raw dolomite and the furnace entering included angle is obtained by controlling the falling point area of the raw dolomite in the converter, the furnace entering grain size of the raw dolomite is strictly controlled, and the influence on slag splashing dynamics caused by stacking into lumps is reduced.
Drawings
FIG. 1 is a schematic diagram illustrating the generation of a partial splashing phenomenon during a slag splashing protection process;
FIG. 2 is a schematic view of the control of the falling point area in the raw dolomite converter.
Detailed Description
For a further understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.
FIG. 1 is a schematic diagram of the existing splashing phenomenon generated in the slag splashing furnace protection process, according to the industrial test of adding raw dolomite in the field slag splashing furnace protection process, the furnace wall thickness before and after slag splashing is measured by a laser thickness gauge, the furnace wall thickness before slag splashing is subtracted by the furnace wall thickness after slag splashing to obtain the existing data of the splashing phenomenon, the transverse data represents different circumferential angles of the furnace wall, and the longitudinal data represents the height of the slag splashing part:
according to the table, at the height of 0-4.7m, the lateral thickness value of the left half of the furnace wall is basically negative, and the right half is positive, which indicates that the slag splashing occurs in the slag splashing process, and the left side is not splashed. Therefore, the slag splashing effect of the left trunnion is extremely poor compared with the slag splashing effect of the right trunnion, and the change of the converter shape is inevitably caused if the slag splashing phenomenon is not controlled in the slag splashing protection process, so that the lance position of the oxygen lance cannot be kept matched with the change of the converter shape, the oxidability (FeO) of slag and the oxygen content of molten steel fluctuate in a large range, and the instability of the process operation is caused.
Example 1
In the method for eliminating the partial splashing phenomenon in the slag splashing furnace protection process of the embodiment, a successful test of a 120-ton top-bottom combined blown converter in a certain steel mill in China is shown by referring to the attached drawing 2, the embodiment controls the falling point area, the adding amount and the adding time of raw dolomite in the converter, and the specific content for eliminating the partial splashing phenomenon in the slag splashing furnace protection process is as follows:
105t of molten iron with the temperature of 1390 ℃ is added into a converter, 25t of scrap steel is added, and the molten iron comprises the following components: 4.84%, Si: 0.36%, Mn: 0.25%, P: 106 percent.
When the smelting end point is reached, carrying out gun temperature measurement sampling, and measuring data: the tapping temperature T is 1655 ℃, the end point C is 0.08%, and the slag melting point T is 1619 ℃.
At the moment, the temperature T-T is higher than 36 ℃ and is higher than 15 ℃, and the time for adding raw dolomite into the furnace is up;
the vertical distance from the hopper to the furnace mouth is selected according to the specification of a top-bottom combined blown converter of each factory, wherein the vertical distance H from the hopper to the furnace mouth in the embodiment is 10m, the height H in the converter and the radius R of a molten pool are respectively 6.2m and 2.3m, and in the embodiment, the included angle of furnace entering is a fixed value of 56.1 degrees because the bunker is fixed. Furthermore, when raw dolomite is input, the drop point area of the raw dolomite in the converter is controlled, so that the variation delta x of the drop point area of the raw dolomite is as follows: and delta x is more than or equal to 0 and less than or equal to 0.85m, and the data is introduced into a relational expression between the grain size of the raw dolomite and the furnace-entering included angle:
therefore, the speed v of the raw dolomite input in the test can be calculated, and the grain diameter d of the raw dolomite is 3 mm-8 mm.
Therefore, when the blowing is finished, a gun is lifted for temperature measurement and sampling, 300kg of raw dolomite with the grain diameter of 3-8 mm is added into the furnace after the steel discharge requirement is met, then the tapping operation is carried out, the slag splashing furnace protection operation is carried out after the tapping, and the slag splashing time is 2.5 min.
After the operation of slag splashing and furnace protection is finished, the thickness of the furnace wall before and after slag splashing is measured through a laser thickness gauge, and the thickness change of the whole circumference of the inner wall of the converter is measured. And subtracting the thickness of the furnace wall before slag splashing from the thickness of the furnace wall after slag splashing, wherein the positive value represents that the furnace wall is thickened, and the negative value represents that the furnace wall is reduced in thickness and slag splashing is unsuccessful. Wherein, horizontal data represent different circumference angles of the furnace wall, and vertical data represent the height of the slag splashing part, and the data are as follows:
according to the data in the table, the operation of the slag splashing furnace protection is greatly improved compared with the operation of the slag splashing furnace protection in the prior art, and the obvious phenomenon of splashing does not occur; in general, the method carries out quantitative control on the addition of the raw dolomite so as to reduce the great influence on the superheat degree of the slag due to the uncertain factors of the addition amount; the invention further controls the falling point area of the raw dolomite in the converter to obtain the relation between the grain size of the raw dolomite and the furnace entering included angle, strictly controls the furnace entering grain size of the raw dolomite, and reduces the influence on slag splashing dynamics caused by stacking and lumping. In general, the comprehensive economic benefit of the invention is particularly outstanding, and the invention obtains consistent and favorable comment of enterprise side.
The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.
Claims (5)
1. A method for eliminating the phenomenon of partial splashing in the slag splashing furnace protecting process is characterized in that: when the smelting of the converter reaches the end point, temperature measurement sampling is carried out, raw dolomite is added, the tapping operation of the converter is carried out, and slag splashing furnace protection operation is carried out after the tapping operation is finished;
controlling the addition amount of the raw dolomite by controlling the relation between the melting point of the slag and the tapping temperature, wherein the tapping temperature is T, and the melting point of the slag is T;
when T-T is more than 15 ℃, the addition amount of raw dolomite is as follows: m ═ T × 7.69 kg;
when T-T is less than or equal to 15 ℃, raw dolomite is not added;
the relationship between the grain size of the raw dolomite and the included angle of the raw dolomite entering the furnace is as follows:
wherein d is the grain size of dolomite; rho is the density of dolomite; v is the furnace entering speed; theta is a furnace entrance included angle; eta is air viscosity coefficient of 1.82 × 10-5Pa · s; g acceleration of gravity of 9.8m/s2(ii) a x is the horizontal distance from the falling point to the starting point; Δ x is the interval variation; H. r is the inner height of the converter and the radius of a molten pool respectively; h is the vertical distance from the hopper to the furnace mouth.
2. The method for eliminating the phenomenon of partial splashing in the slag splashing protection process of the furnace as claimed in claim 1, wherein the method comprises the following steps: the raw dolomite is subjected to vibration type feeding through vibration equipment.
3. The method for eliminating the phenomenon of partial splashing in the slag splashing protection process of the furnace as claimed in claim 2, wherein the method comprises the following steps: the density rho of the raw dolomite is 3.0 multiplied by 103kg/m3。
4. The method for eliminating the phenomenon of partial splashing in the slag splashing protection process of the furnace as claimed in claim 3, wherein the method comprises the following steps: the amount of change in Δ x is: and deltax is more than or equal to 0 and less than or equal to 0.85 m.
5. The method for eliminating the phenomenon of partial splashing in the slag splashing protection process of the furnace as claimed in claim 3, wherein the method comprises the following steps: the furnace entrance included angle theta is (0, pi/2).
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| RU2114919C1 (en) * | 1997-06-10 | 1998-07-10 | Акционерное общество "Новолипецкий металлургический комбинат" | Method for repair of converter lining |
| US7914599B2 (en) * | 2004-11-17 | 2011-03-29 | Ism, Inc. | Slag conditioner composition, process for manufacture and method of use in steel production |
| CN102212629A (en) * | 2011-05-23 | 2011-10-12 | 东北大学 | Method for inhibiting and regulating distribution segregation of iron-making reactor by using pneumatic principle |
| CN104531940A (en) * | 2015-01-05 | 2015-04-22 | 山东钢铁股份有限公司 | Converter final slag thickening method |
| CN104694692B (en) * | 2015-03-20 | 2017-01-04 | 山东钢铁股份有限公司 | A kind of method utilizing converter slag fettling |
| CN106947845A (en) * | 2017-05-23 | 2017-07-14 | 攀钢集团西昌钢钒有限公司 | A kind of method of slag splashing |
| CN107287382A (en) * | 2017-08-23 | 2017-10-24 | 首钢长治钢铁有限公司 | A kind of method of remained converter slag slag removing and furnace protecting |
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