CN113122671A - Method for controlling erosion of high-titanium molten iron converter slag on furnace lining - Google Patents

Method for controlling erosion of high-titanium molten iron converter slag on furnace lining Download PDF

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CN113122671A
CN113122671A CN202110290357.8A CN202110290357A CN113122671A CN 113122671 A CN113122671 A CN 113122671A CN 202110290357 A CN202110290357 A CN 202110290357A CN 113122671 A CN113122671 A CN 113122671A
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slag
furnace
converter
molten iron
erosion
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CN113122671B (en
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华福波
王劼
杨昌涛
陶昌德
伍从应
刘明波
杨龙飞
蓝桂年
文安义
郑新泉
陈浩
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Shougang Shuicheng Iron and Steel Group Co Ltd
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Shougang Shuicheng Iron and Steel Group Co Ltd
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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
    • 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
    • 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
    • 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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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention belongs to the technical field of metallurgical steelmaking, and particularly relates to a method for controlling erosion of high-titanium molten iron converter slag on a furnace lining; by adopting the method of adding light-burned dolomite into a converter before adding the steel scrap and the molten iron, the slag remained in the last furnace and TiO formed by the blowing oxidation of the furnace are solidified2The erosion of the slag line on the furnace lining is reduced, a low-lance-position, large-flow and long-time lance pressing mode is adopted when a lance is pressed at the end point, the content of final slag (FeO) is reduced, and the erosion of the slag line on the furnace lining when the slag is poured into a converter and steel is tapped is controlled; meanwhile, a low-high-low slag splashing gun position mode is adopted, and the slag splashing furnace protection effect is ensured through three times of splashing and cooling. Make TiO not to contact with the surface of the substrate2Greatly reduces the erosion degree of the furnace lining, ensures the safety and the regularity of the furnace condition, directly reduces the frequency and the safety risk of furnace protection, and improves the rotary furnaceThe furnace production rhythm reduces the refractory consumption and saves the steel-making cost.

Description

Method for controlling erosion of high-titanium molten iron converter slag on furnace lining
Technical Field
The invention belongs to the technical field of metallurgical steelmaking, and particularly relates to a method for controlling erosion of high-titanium molten iron converter slag on a furnace lining.
Background
The furnace age is an important economic and technical index for converter steelmaking, and directly influences the operating rate of converter steelmaking and the cost of refractory materials. In actual production, when the converter is smelted, the furnace lining refractory material is gradually thinned due to the impact of steel scrap and molten iron, the erosion and corrosion of high-temperature metal liquid, oxygen flow and furnace slag, so that the furnace shape, the smelting effect and the service life of the converter are influenced. In order to maintain a good furnace shape, ensure the normal flow field of molten metal and slag in the furnace and guarantee the metallurgical effect, the furnace shape maintenance work is required. However, the furnace protection consumes a large amount of refractory materials, occupies production time, influences production rhythm and increases production cost.
The titaniferous iron ore is an important strategic resource in western China, molten iron with high titanium content is obtained by blast furnace smelting, and titaniferous slag is generated by converter smelting due to TiO thereof2The service life of the lining of the converter is greatly influenced by the high content of the (acidic oxide) and the special physical and chemical properties. In the existing converter operation, the light-burned dolomite consumption is increased to carry out slag thickening and the converter protection frequency is increased to ensure that the furnace condition is safely controlled, and the operation mode has the defects of slow production rhythm, large light-burned dolomite consumption, high continuous casting tundish cost and the like.
From the Ellingham oxygen bitmap (as shown in FIG. 1), it can be known that each element in the molten ironThe oxidation sequence is that Ti is firstly oxidized and then elements such as Si, V, Mn, Cr, P, S and the like are added, and Ti is oxidized to generate TiO2And into the slag. TiO22In alkaline slag (R)>2.0) is acidic, and the Ti has small particle radius and large electrostatic potential and is easy to react with O released from alkaline oxides in slag2-The ions are combined to generate composite anions, and the anions are gradually combined into larger anion groups to increase the viscosity of the slag; and TiO22The dissolution of CaO and MgO in the slag is promoted, and the number of CaO and MgO particles precipitated in the slag due to supersaturation is reduced. Therefore, under the combined action of the two, the viscosity of the slag is changed along with the TiO when in non-reducing atmosphere2The increase of the content causes difficult thorough melting of the slag, which causes poor steel-slag separation effect at the end point of the converter, and the iron content of the slag is higher, which causes the consumption of iron and steel materials to rise and seriously restricts the slag splashing furnace protection effect. Furthermore, TiO2The influence on the semisphere temperature of the converter final slag is obvious, and the condition of measuring the melting point by sampling the slag is known, and every 1 percent of TiO in the slag is added2The slag melting point decreases by about 27 ℃. Converter final slag TiO2The content is 3-6%, and the hemisphere temperature is reduced by about 121.5 ℃. FIG. 2 shows FeO-CaO-V2O5The phase diagram of the ternary slag system shows the final slag V of the converter2O5When the content reaches more than 1.3 percent, the content has obvious influence on the melting temperature of the slag, finally the erosion resistance of a slag splashing layer is deteriorated when the slag splashing furnace protection is carried out, and the furnace condition of the converter is seriously deteriorated under the action of high temperature and peroxide slag. In order to maintain the furnace shape to ensure the metallurgical effect and the smelting safety of the converter, the furnace protection frequency must be increased, the furnace protection finished products are increased, and the production rhythm is influenced. The long furnace protection time greatly reduces the furnace temperature, the furnace entering heat needs to be increased for supplementing heat balance, the furnace type corrosion is easily aggravated again, and the increase of the furnace entering molten iron amount is inconsistent with the work of saving iron and increasing steel. Therefore, developing a new rapid furnace protection process which ensures the quality of the furnace protection and the smelting safety becomes one of the focus and the difficulty of improving the furnace protection effect of smelting the vanadium-titanium molten iron.
Patent document CN201810209687.8 discloses a method for reducing erosion of converter lining, which comprises adding dolomite into a converter, adding semisteel into the converter, blowing while adding the semisteel into the converter, and blowingActive lime, high-magnesium lime, an acidic composite slagging agent and waste converter slag are added, the lance position and the oxygen blowing strength of an oxygen lance are controlled, and the alkalinity of end-point slag is controlled to be 3-4, so that end-point molten steel and end-point slag are obtained. By adopting dolomite for slagging and adding the waste slag of the converter to replace part of metallurgical auxiliary materials, the TFe content in the end-point slag is reduced, the corrosion rate of the converter lining is obviously reduced, the service life of the converter is prolonged, and the smelting effect is not influenced. However, in practical application, it is found that if the basicity is calculated according to the calculation method, the actual basicity of the titanium-containing slag is relatively low, which is unfavorable for controlling the acid-base ratio of the slag, and the acid oxide in the slag in a free state is increased, which is unfavorable for controlling the corrosion of the slag to a molten pool and is also unfavorable for dephosphorization and desulfurization. And the titanium-containing slag is not only a problem of corrosion of the lining caused by TFe, but also TiO2It also has a large effect on the life of the converter lining.
Disclosure of Invention
The invention provides a method for controlling the erosion of the slag of the high-titanium molten iron converter to a furnace lining to solve the problems.
The method is realized by the following technical scheme:
a method for controlling the erosion of the slag of a high-titanium molten iron converter to a furnace lining comprises the following steps:
1. smelting in an early stage: 1000kg of light-burned dolomite is added into a converter with the slag amount of about 3000kg, the converter is stirred and fried with scrap steel, preheated and added with molten iron, the blowing gun position is 1.8m, and the oxygen supply flow is 22000m3H, adding light-burned dolomite after ignition is successful, wherein the adding system is as follows: when the titanium content in the molten iron is 0.050-0.150%, the addition amount of the light-burned dolomite is 0 kg; when the titanium content in the molten iron is 0.151-0.200%, the addition amount of the light-burned dolomite is 200 kg; when the titanium content in the molten iron is 0.201-0.250%, the addition amount of the light-burned dolomite is 300 kg; when the content of titanium in the molten iron is more than 250 percent, the addition amount of the light-burned dolomite is 500 kg. Adding 635-2290kg of lime, immediately reducing the lance position to 1.2m after reacting for 20s, then adding 70-300kg of sintering return ores into the furnace, judging blowing to 2.8-3.2min through the flame at the furnace mouth, removing slag, adding 270-980kg of lime, controlling the alkalinity to 1.8, and reducing the oxygen supply flow to 20000m3H, and reducing the gun position to 1.1m, and blowingGradually increasing the gun position to 1.7m within 4-8min of smelting;
2. in the middle stage of smelting: lime is added in three batches within 4-6min of blowing, the total adding amount is 450-1290kg, and the alkalinity of the final slag is 2.5-3.2. The oxygen supply flow is recovered to 22000m within 8-11min of converting3And the gun position is periodically adjusted up and down between 1.3m and 1.7 m.
Further, the temperature of the molten iron is 1300-1410 ℃, the silicon content is 0.100-0.600%, and the titanium content is 0.150-0.400%.
Further, the alkalinity calculation method is optimized as R ═ CaO)/(% SiO)2+0.5(％TiO2))。
Further, the periodicity is controlled by 20s, specifically, the period is maintained for 20s at 1.7m, then decreased to 1.3m, then maintained for 20s, and then increased to 1.7m, and then maintained for 20s, and the total time is 3 min.
3. And (3) in the later stage of smelting: smelting to 10.5-11.5min, adding 200kg of light-burned dolomite, gradually reducing the lance position to 1.1m when reducing the lance position to 12min, adding 10kg of coke breeze into the furnace from a high-position stock bin, starting a constant pressure lance to operate, wherein the lance position is 1.1m, the oxygen supply flow is 23000m3And h, the gun pressing time is 55-65s, the gun is lifted to perform furnace reversing and slag pouring after the gun pressing is finished, and the slag pouring amount is about 40%.
4. And (4) rocking the furnace to discharge steel: and (4) shaking the furnace to tap after deslagging is finished, and adding 5kg of carburant into the furnace after the converter stops stably to tap.
5. Slag splashing: after tapping is finished, the converter is shaken to a zero position, 10kg of coke is added into the converter from a high-position storage bin, then the converter is put into a gun for slag splashing operation, the slag splashing adopts a low-high-low gun position control mode, the lowest is 0.30-0.45m, the highest is 0.9-1.1m, the nitrogen flow is 29000m according to the low gun position3H, high gun position 27000m3And h, controlling the slag splashing time to be 2.0-2.5min, pouring all slag after the slag splashing operation is finished, measuring the thickness of the converter lining of the converter by using a converter shell thickness gauge, and comparing the measured value with the measured value of the last furnace.
FIG. 3 shows CaO-SiO2-TiO2The ternary slag system phase diagram shows that the slag is TiO2The content is 5%, when the binary alkalinity R is 1.2 and 0.64, the melting point of the slag is lowest; at the same time, the furnaceSlag temperature and TiO2The content has a great influence on the viscosity, and the characteristic directly influences the steel-slag separation effect at the early stage of blowing. FIG. 4 shows the slag TiO at different temperatures2The influence of the content on the viscosity of the product can be seen from the analysis of the graph: the viscosity of the slag under different temperature conditions is dependent on TiO2The content is reduced with the increase of the content, and TiO is increased with the temperature of a molten pool2The influence of the content on the viscosity of the slag is reduced; TiO at 1400 deg.C2The influence of the content on the slag viscosity is most obvious, and the lower the content is, the greater the influence on the slag viscosity is.
Therefore, when smelting slag in the early stage of high-titanium molten iron production, [ Ti ] in molten iron]Rapidly oxidized to the slag and to the TiO2The slag is stable in slag, and the primary slag is low-alkalinity, multi-component and high-oxidizing slag. The more the mineral components of the primary slag are, the correspondingly lower the melting point is, the faster the slagging speed is, and the better the Ti removal effect is.
In conclusion, the beneficial effects of the invention are as follows: the invention adopts a method of adding light-burned dolomite into a converter before adding scrap steel and molten iron to solidify the slag remained in the last furnace and TiO formed by blowing and oxidizing in the last furnace2The erosion of the slag line on the furnace lining is reduced, a low-lance-position, large-flow and long-time lance pressing mode is adopted when a lance is pressed at the end point, the content of final slag (FeO) is reduced, and the erosion of the slag line on the furnace lining when the slag is poured into a converter and steel is tapped is controlled; meanwhile, a low-high-low slag splashing gun position mode is adopted, and the slag splashing furnace protection effect is ensured through three times of splashing and cooling. Make TiO not to contact with the surface of the substrate2The corrosion degree of the furnace lining is greatly reduced, the safety and the regularity of the furnace condition are ensured, the furnace protection frequency and the safety risk are directly reduced, the production rhythm of the converter is improved, the consumption of refractory materials is reduced, and the steel-making cost is saved.
Wherein 1000kg of light-burned dolomite is preheated together with the scrap steel to promote melting. Solidifying the slag left in the last furnace and TiO formed by the blow-on oxidation of the furnace2The corrosion to the furnace lining is reduced; meanwhile, the method can control the over-slow temperature rise of a molten pool and poor slagging effect caused by adding a large amount of light-burned dolomite during blowing, and cannot fully utilize MgO in the light-burned dolomite to react a Ti-O reaction product TiO2Absorbing and curing to make it directly contact with furnaceThe lining reacts and further erodes the lining. By lightly burning dolomite to fix titanium, TiO is reduced2The dephosphorization is influenced by the large consumption of lime, the reaction is prevented from generating a large amount of titanium-containing compounds with low melting points and poor stability, and a large amount of free TiO begins to be decomposed in the early stage of smelting2And erode the furnace lining. Aiming at the specific properties of the molten iron containing titanium and the actual production experience on site, the alkalinity calculation method is optimized to R ═ CaO/(% SiO)2+0.5(％TiO2) Alkalinity in earlier stage of smelting is controlled according to 1.8, and TiO is controlled2It is favorable for creating low alkalinity to the erosion of furnace lining. The alkalinity calculation formula was optimized to include the percent acidic oxide according to the TiO2 attribute. The basicity is closer to the molten iron smelting that contains titanium in this application, distinguishes with the non-ferrotitanium water basicity calculation mode, can effective control slag acid-base proportion, and then is the acid oxide of free state in the control slag, does benefit to the erosion that reduces the slag to the furnace lining, also does benefit to the dephosphorization desulfurization. In the early stage of smelting, a proper iron-containing cold material (namely sintering return ores) is added according to the temperature of molten iron, and the operation of low lance position and large flow is adopted, so that the better dynamic condition is improved, the temperature of a molten pool is quickly improved, and the slag-steel separation effect is improved; secondly, the higher content of FeO in the slag is kept, namely the slag is controlled according to an iron slag forming way, which is beneficial to the formation of initial slag and the TiO formation2Stably exists in the slag and controls the erosion of the furnace lining. 200kg of light-burned dolomite is added before the lance position is reduced in the later stage of smelting to control the decomposition of titanium-containing compounds in a high-temperature state and to control TiO in slag2And curing to control the erosion of the furnace lining. When the gun is pressed at the end point, 10kg of coke is added into the converter, and a low-gun position, large-flow and long-time gun pressing mode is adopted to reduce the content of final slag (FeO) and form the low-iron titanium-containing converter final slag. The slag remaining amount is controlled according to 60 percent of the total slag amount to be matched with a 100t converter model, 5kg (one bag) of carburant is thrown into the converter in the tapping process, secondary oxidation of slag in the tapping process can be controlled, erosion of a furnace lining slag line in the tapping process is reduced, and the slag melting point is prevented from being reduced to further influence the slag splashing effect. Adopt andaccording to the conventional 'high-low' different 'low-high-low' slag splashing gun position modes, slag is splashed on a furnace lining while being cooled at a low gun position and a large flow rate, then the gun position is increased, the flow rate is reduced, a splashed layer is cooled to improve the adhesion effect, and finally the low gun position is adopted to splash and cool the slag which is not adhered again. The slag splashing furnace protection effect is ensured by three times of splashing and cooling. The furnace protection with medium and low alkalinity is realized by more accurate adding amount and mode control, and the consumption of corresponding slag charge is lower. The influence of the slag TFe on the erosion of the furnace lining is reduced, and the problem of the erosion of the furnace lining under the dual factors of the contents of the slag TiO2 and the TFe is reduced to a certain extent aiming at the special characteristics of the erosion of the furnace lining of the converter containing titanium molten iron.
Drawings
Fig. 1 is an Ellingham oxygen bitmap.
FIG. 2 shows FeO-CaO-V2O5Ternary slag system phase diagram.
FIG. 3 shows CaO-SiO2-TiO2Ternary slag system phase diagram.
FIG. 4 shows the slag TiO at different temperatures2The effect of the content on its viscosity.
FIG. 5 is SEM results of the final slag of example 1.
FIG. 6 is SEM results of the final slag of example 2.
FIG. 7 is the SEM results of the final slag of example 3.
FIG. 8 is SEM results of comparative example final slag.
Detailed Description
The following is a detailed description of the embodiments of the present invention, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are included in the scope of the present invention as claimed in the claims.
Example 1
A method for controlling the erosion of the slag of a high-titanium molten iron converter to a furnace lining comprises the following steps:
1. smelting in an early stage:
the residue quantity after the slag splashing of the previous furnace is finished is about 3000kg, and light slag is added into the furnace from a high-level bin before the furnace enters the scrap steel1000kg of dolomite is burnt, and molten iron is added after the dolomite is stir-fried and preheated along with the scrap steel, wherein the charging conditions of the molten iron are shown in Table 1. The position of the blow gun is 1.8m, and the oxygen supply flow is 22000m3H, adding 500kg of light-burned dolomite after ignition is successful, adding 1470kg of lime after reaction for 20s, immediately reducing the lance position to 1.2m after reaction for 20s, then adding 300kg of sintered return ores into the furnace, judging blowing by flame at the furnace mouth until 2.8min, taking slag, adding 630kg of lime, controlling the alkalinity to be 1.8, and reducing the oxygen supply flow to 21000m3Reducing the gun position to 1.1m, and gradually increasing the gun position to 1.7m within 4-8min of blowing;
2. in the middle stage of smelting: lime is added into the blowing for 4min to 6min in three batches, the total addition is 1170kg, and the oxygen supply flow is recovered to 22000m within 8min to 11min of blowing3And the gun position is periodically adjusted up and down between 1.3m and 1.7 m.
Further, the periodicity is controlled by 20s, specifically, the period is maintained for 20s at 1.7m, then decreased to 1.3m, then maintained for 20s, and then increased to 1.7m, and then maintained for 20s, and the total time is 3 min.
3. And (3) in the later stage of smelting:
when smelting is carried out for 11min, 200kg of light-burned dolomite is added, the lance position is gradually reduced to 1.1m when 12min, 10kg of coke is added into the furnace from a high-level stock bin, the coke is opened, the operation of a constant pressure lance is carried out, the lance position of the pressure lance is 1.1m, the oxygen supply flow is 23000m3And h, the gun pressing time is 61s, the gun is lifted to perform furnace reversing and slag pouring after the gun pressing is finished, and the slag pouring amount is about 40%.
4. And (4) rocking the furnace to discharge steel: and (4) shaking the furnace to tap after deslagging is finished, and adding 5kg of carburant into the furnace after the converter stops stably to tap.
5. Slag splashing: after tapping is finished, the converter is shaken to a zero position, 10kg of coke is added into the converter from a high-position storage bin, then the converter is put into a gun for slag splashing operation, the slag splashing adopts a low-high-low gun position control mode, the lowest gun position is 0.40m, the highest gun position is 1.0m, and the nitrogen flow is 29000m according to the low gun position3H, high gun position 27000m3And h, controlling the slag splashing time to be 2.2min, pouring all slag after the slag splashing is finished, measuring the thickness of the converter lining of the converter by using a converter shell thickness gauge, and comparing the measured value with the measured value of the last furnace time, wherein the thickness of the converter lining is increased by 18mm after the furnace time is smelted.
SEM results of converter final slag taken in a converter are shown in FIG. 5, and chemical compositions thereof are shown in Table 2, and it is understood from Table 2 that the final slag basicity is 2.74 and the (TFe) content is 14.23%, (TiO)2) The content is 3.13 percent, and the TiO slag in each stage of smelting can be known by combining the thickness of the furnace lining2The erosion degree of the furnace lining is greatly reduced.
Example 2
A method for controlling the erosion of the slag of a high-titanium molten iron converter to a furnace lining comprises the following steps:
1. smelting in an early stage:
the amount of slag remained after the slag splashing of the previous furnace is finished is about 3000kg, 1000kg of light-burned dolomite is added into the furnace from a high-level bunker before the furnace enters the waste steel, and the light-burned dolomite is stir-fried and preheated along with the waste steel and then added with molten iron, wherein the charging conditions of the molten iron are shown in table 1. The position of the blow gun is 1.8m, and the oxygen supply flow is 22000m3H, adding 300kg of light-burned dolomite after ignition is successful, adding 1330kg of lime after reaction for 20s, immediately reducing the lance position to 1.2m after reaction for 20s, then adding 100kg of sintered return ores into the furnace, judging blowing by flame at the furnace mouth until 3.1min, slagging, adding 570kg of lime, controlling the alkalinity to be 1.8, and reducing the oxygen supply flow to 21000m3Reducing the gun position to 1.1m, and gradually increasing the gun position to 1.7m within 4-8min of blowing;
2. in the middle stage of smelting: lime is added into the blowing process for 4min to 6min for three times, the total adding amount is 970kg, and the oxygen supply flow is recovered to 22000m within 8min to 11min of the blowing process3And the gun position is periodically adjusted up and down between 1.3m and 1.7 m.
Further, the periodicity is controlled by 20s, specifically, the period is maintained for 20s at 1.7m, then decreased to 1.3m, then maintained for 20s, and then increased to 1.7m, and then maintained for 20s, and the total time is 3 min.
3. And (3) in the later stage of smelting:
when smelting is carried out for 11.05min, 200kg of light-burned dolomite is added, the lance position is gradually reduced to 1.1m when 12min, 9kg of coke breeze is added into the furnace from a high-level stock bin, the operation of a constant pressure lance is started, the lance position of the pressure lance is 1.1m, the oxygen supply flow is 23000m3And h, the gun pressing time is 58s, the gun is lifted after the gun pressing is finished, the furnace is turned over, and the slag is pouredThe amount is about 40%.
4. And (4) rocking the furnace to discharge steel: and (4) shaking the furnace to tap after deslagging is finished, and adding 5kg of carburant into the furnace after the converter stops stably to tap.
5. Slag splashing: after tapping is finished, the converter is shaken to a zero position, 10kg of coke is added into the converter from a high-position storage bin, then the converter is put into a gun for slag splashing operation, the slag splashing adopts a low-high-low gun position control mode, the lowest gun position is 0.35m, the highest gun position is 0.95m, and the nitrogen flow is 29000m according to the low gun position3H, high gun position 27000m3And h, controlling the slag splashing time to be 2.32min, pouring all slag after the slag splashing is finished, measuring the thickness of the converter lining of the converter by using a converter shell thickness gauge, and comparing the measured value with the measured value of the last furnace time, wherein the thickness of the converter lining is increased by 20mm after the furnace time is smelted.
SEM results of converter final slag taken in a converter are shown in FIG. 6, and chemical compositions thereof are shown in Table 2, and it is understood from Table 2 that the final slag basicity is 2.63 and the (TFe) content is 15.12%, (TiO)2) The content is 3.06 percent, and the TiO slag in each stage of smelting can be known by combining the thickness of the furnace lining2The erosion degree of the furnace lining is greatly reduced.
Example 3
A method for controlling the erosion of the slag of a high-titanium molten iron converter to a furnace lining comprises the following steps:
1. smelting in an early stage:
the amount of slag remained after the slag splashing of the previous furnace is finished is about 3000kg, 1000kg of light-burned dolomite is added into the furnace from a high-level bunker before the furnace enters the waste steel, and the light-burned dolomite is stir-fried and preheated along with the waste steel and then added with molten iron, wherein the charging conditions of the molten iron are shown in table 1. The position of the blow gun is 1.8m, and the oxygen supply flow is 22000m3H, adding 300kg of light-burned dolomite after ignition is successful, adding 1250kg of lime after reaction for 20s, immediately reducing the lance position to 1.2m after reaction for 20s, then adding 70kg of sintered return ores into the furnace, judging blowing to 3.2min through the flame at the furnace mouth for slagging, adding 540kg of lime at the moment, controlling the alkalinity to be 1.8, and reducing the oxygen supply flow to 21000m3Reducing the gun position to 1.1m, and gradually increasing the gun position to 1.7m within 4-8min of blowing;
2. in the middle stage of smelting: lime is added into the blowing for 4min to 6min in three batches, the total adding amount is 1140kg, and the blowing is carried out for 8min to 11mThe in recovery oxygen supply flow is 22000m3And the gun position is periodically adjusted up and down between 1.3m and 1.7 m.
Further, the periodicity is controlled by 20s, specifically, the period is maintained for 20s at 1.7m, then decreased to 1.3m, then maintained for 20s, and then increased to 1.7m, and then maintained for 20s, and the total time is 3 min.
3. And (3) in the later stage of smelting:
when smelting is carried out for 10.89min, 200kg of light-burned dolomite is added, the lance position is gradually reduced to 1.1m when 12min, 10kg of coke breeze is added into the furnace from a high-level stock bin, the operation of a constant pressure lance is started, the lance position of the pressure lance is 1.1m, the oxygen supply flow is 23000m3And h, the gun pressing time is 62s, the gun is lifted to perform furnace reversing and slag pouring after the gun pressing is finished, and the slag pouring amount is about 40%.
4. And (4) rocking the furnace to discharge steel: and (4) shaking the furnace to tap after deslagging is finished, and adding 5kg of carburant into the furnace after the converter stops stably to tap.
5. Slag splashing: after tapping is finished, the converter is shaken to a zero position, 10kg of coke is added into the converter from a high-position storage bin, then the converter is put into a gun for slag splashing operation, the slag splashing adopts a low-high-low gun position control mode, the lowest gun position is 0.38m, the highest gun position is 1.02m, and the nitrogen flow is 29000m according to the low gun position3H, high gun position 27000m3And h, controlling the slag splashing time to be 2.27min, pouring all slag after the slag splashing is finished, measuring the thickness of the converter lining of the converter by using a converter shell thickness gauge, and comparing the measured value with the measured value of the last furnace time, wherein the thickness of the converter lining is increased by 21mm after the furnace time is smelted.
SEM results of converter final slag taken in a converter are shown in FIG. 7, and chemical compositions thereof are shown in Table 2, and it is understood from Table 2 that the final slag basicity is 2.86 and the (TFe) content is 14.87%, (TiO)2) The content is 3.48 percent, and the TiO slag in each stage of smelting can be known by combining the thickness of a furnace lining2The erosion degree of the furnace lining is greatly reduced.
Comparative example
1. Smelting in an early stage:
and (4) performing slag-leaving-free operation after the last slag splashing is finished, wherein the molten iron charging conditions are shown in Table 1. The position of the blow gun is 1.8m, and the oxygen supply flow is 21000m3H, adding 1800kg of lime after ignition is successful, reacting for 30s, and adding 1 of light-burned dolomite600kg, reducing the gun position to 1.25m after reacting for 20s, judging blowing to 3.5min through the flame at the furnace mouth, slagging, adding 600kg of lime and 200kg of lightly burned dolomite at the moment, gradually increasing the gun position to 1.7m within 5-8 min of blowing, adding 400kg of lime into 5.1min of blowing, adding 400kg of lime into 6min of blowing, and adjusting the gun position in a non-periodic manner within 1.3-1.7m for 8-12.5 min of blowing.
2. And (3) in the later stage of smelting:
when smelting is carried out for 12.57min, the lance position is reduced to 1.2m, the lance position is pressed to 1.2m, the lance position is started, the oxygen supply flow is 21000m3And h, the gun pressing time is 40s, the gun is lifted to perform furnace reversing and slag pouring after the gun pressing is finished, and the slag pouring amount is about 50%.
3. And (4) rocking the furnace to discharge steel: and after the slag pouring is finished, the furnace is shaken to tap steel, and no carburant is added.
4. Slag splashing: after tapping, slag splashing adopts a high-low gun position control mode, the lowest is 0.43m, the highest is 1.11m, and the nitrogen flow is 28000m3And h, slag splashing time is 1.85min, after slag splashing is finished, all slag is poured out, the thickness of the converter lining of the converter is measured by using a converter shell thickness gauge, the measured value is compared with the measured value of the last furnace time, and the thickness of the converter lining is increased by 2mm after the furnace time is smelted.
SEM results of final slag formation of converter taken in the converter are shown in FIG. 8, chemical compositions are shown in Table 2, and it is understood from Table 2 that the final slag basicity is 3.43, (TFe) content is 18.86%, (TiO)2) The content is 2.41 percent, and the TiO slag in each stage of smelting can be seen by combining the thickness of the furnace lining2The erosion to the furnace lining is serious.
TABLE 1 charging iron conditions
Figure BDA0002982235980000101
TABLE 2 slag composition after end of dephosphorization phase (wt%)
Figure BDA0002982235980000102

Claims (10)

1. A method for controlling the erosion of the slag of a high-titanium molten iron converter to a furnace lining is characterized by comprising the following steps:
(1) smelting in an early stage: adding 1000kg of light-burned dolomite into a converter with a slag amount of 3000kg, stir-frying and preheating the converter along with scrap steel, adding molten iron, successfully adding the light-burned dolomite after ignition, reacting for 20s, adding lime twice, and adjusting the gun position and the flow rate;
(2) in the middle stage of smelting: adding lime for the third time in three batches at 4-6min, wherein the total amount is 450-1290kg, and the alkalinity of the final slag is 2.5-3.2;
(3) and (3) in the later stage of smelting: adding 200kg of light-burned dolomite, reducing the gun position, adding 10kg of coke dices when the gun is pressed at the end point, and then reversing the furnace and deslagging;
(4) and (4) rocking the furnace to discharge steel: after the converter stops stably, adding 5kg of carburant into the converter, and tapping;
(5) slag splashing: and (3) shaking the converter to a zero position, adding 10kg of coke, then putting a gun for slag splashing operation, pouring out slag after slag splashing is finished, and measuring the thickness of the converter lining of the converter by using a converter shell thickness gauge.
2. The method for controlling the erosion of the furnace lining by the molten iron converter slag with high titanium content as claimed in claim 1, wherein the temperature of the molten iron is 1300-1410 ℃, the silicon content is 0.100-0.600%, and the titanium content is 0.150-0.400%.
3. The method for controlling the erosion of the furnace lining by the molten iron high-titanium converter slag according to claim 1, wherein after the ignition is successful, light-burned dolomite is added according to the following addition system: when the titanium content in the molten iron is 0.050-0.150%, the addition amount of the light-burned dolomite is 0 kg; when the titanium content in the molten iron is 0.151-0.200%, the addition amount of the light-burned dolomite is 200 kg; when the titanium content in the molten iron is 0.201-0.250%, the addition amount of the light-burned dolomite is 300 kg; when the content of titanium in the molten iron is more than 250 percent, the addition amount of the light-burned dolomite is 500 kg.
4. The method for controlling the erosion of the furnace lining by the molten iron high-titanium converter slag as claimed in claim 1, wherein the lime is added twice, the first addition is 635-2290kg, and the second addition is 270-980 kg.
5. The method for controlling the erosion of the furnace lining by the molten iron converter slag with high titanium content according to claim 1 or 4, characterized in that lime is added twice, 70-300kg of sintered return ores are added into the furnace after the lime is added for the first time and the lime is added for the second time when the furnace is blown to 2.8-3.2min for slag removal, and the target alkalinity is 1.8.
6. The method for controlling the erosion of the furnace lining by the molten iron converter slag with high titanium content according to claim 1, wherein the adjusting of the lance position and the flow rate specifically comprises: the position of the blow gun is 1.8m, and the oxygen supply flow is 22000m3H; after the first lime addition, the reaction was carried out for 20s to reduce the lance height to 1.2 m; the oxygen supply flow is reduced to 21000m after the lime is added for the second time3At the same time, the gun position is lowered to 1.1 m. Gradually increasing the lance position to 1.7m within 4-8min of converting; recovering oxygen supply flow to 22000m in 8-11min3And adjusting the gun position up and down periodically between 1.3 and 1.7 m.
7. The method for controlling the erosion of the lining by the molten iron high-titanium converter slag according to claim 6, wherein the periodicity is controlled by keeping for 20s at 1.7m, then decreasing to 1.3m, then keeping for 20s, then increasing to 1.7m, and then keeping for 20s, and the total time is 3 min.
8. The method for controlling the erosion of the furnace lining by the molten iron converter slag with high titanium content according to claim 1, wherein the reduction of the lance position is realized by adding light burned dolomite during smelting for 10.5-11.5min, gradually reducing the lance position to 1.1m during 12min and controlling the oxygen supply flow to 23000m3/h。
9. The method for controlling the erosion of the lining by the molten iron blast furnace slag according to claim 1, wherein the terminal pressure lance has a lance position of 1.1m and an oxygen supply flow rate of 230 m00m3And h, the gun pressing time is 55-65 s.
10. The method for controlling the erosion of the furnace lining by the molten iron converter slag with high titanium content according to claim 1, wherein the slag splashing adopts a low-high-low lance position control mode, and specifically comprises the following steps: minimum 0.30-0.45m and maximum 0.9-1.1m, nitrogen flow 29000m at low lance position3H, high gun position 27000m3H is controlled, and the slag splashing time is 2.0-2.5 min.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102816887A (en) * 2012-08-22 2012-12-12 首钢水城钢铁（集团）有限责任公司 Method for directly smelting high-titanium molten iron by using converter
CN105177217A (en) * 2015-08-20 2015-12-23 山东西王特钢有限公司 Process for reducing steel slag quantity during converter smelting
CN107090535A (en) * 2017-05-24 2017-08-25 首钢总公司 A kind of converter smelting high phosphorus titaniferous molten iron protects the control method of carbon tapping
CN108330243A (en) * 2018-03-14 2018-07-27 攀钢集团攀枝花钢铁研究院有限公司 A method of it reducing converter lining and corrodes
CN109897933A (en) * 2019-04-04 2019-06-18 中天钢铁集团有限公司 A kind of efficient smelting process of the low-phosphorous clean steel of converter producing
CN110373511A (en) * 2019-07-17 2019-10-25 邯郸钢铁集团有限责任公司 A kind of converter smelting process of low lime consumption

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102816887A (en) * 2012-08-22 2012-12-12 首钢水城钢铁（集团）有限责任公司 Method for directly smelting high-titanium molten iron by using converter
CN105177217A (en) * 2015-08-20 2015-12-23 山东西王特钢有限公司 Process for reducing steel slag quantity during converter smelting
CN107090535A (en) * 2017-05-24 2017-08-25 首钢总公司 A kind of converter smelting high phosphorus titaniferous molten iron protects the control method of carbon tapping
CN108330243A (en) * 2018-03-14 2018-07-27 攀钢集团攀枝花钢铁研究院有限公司 A method of it reducing converter lining and corrodes
CN109897933A (en) * 2019-04-04 2019-06-18 中天钢铁集团有限公司 A kind of efficient smelting process of the low-phosphorous clean steel of converter producing
CN110373511A (en) * 2019-07-17 2019-10-25 邯郸钢铁集团有限责任公司 A kind of converter smelting process of low lime consumption

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