CN109338041B - Method for applying limestone to LF refining instead of calcium carbide - Google Patents
Method for applying limestone to LF refining instead of calcium carbide Download PDFInfo
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- CN109338041B CN109338041B CN201811244163.9A CN201811244163A CN109338041B CN 109338041 B CN109338041 B CN 109338041B CN 201811244163 A CN201811244163 A CN 201811244163A CN 109338041 B CN109338041 B CN 109338041B
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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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/076—Use of slags or fluxes as treating agents
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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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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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 discloses a method for applying limestone to LF refining instead of calcium carbideAnd (2) after the ladle enters a working position, switching on and opening bottom blowing argon, adding 3.0-5.0kg/t of lime steel and 2.0-3.0kg/t of limestone steel, simultaneously adding 0-0.7kg/t of aluminum particles of steel, 0-0.8kg/t of silicon calcium powder of steel and 0-1.0kg/t of silicon iron powder deoxidizer according to different steel types, stirring for 3-5min, adjusting the flow of argon, and then reducing the electrode for heating. Limestone is heated and decomposed to generate CaO and CO2In which CaO is introduced into the slag as a slag-forming material, CO2Filled in the steel slag to play a foaming role and achieve the effect of submerged arc operation. According to the invention, cheap limestone is used as a foaming agent instead of expensive calcium carbide, so that the expected submerged arc effect is achieved, the refining production cost is obviously reduced, and the labor intensity of workers is reduced.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a method for applying limestone to LF refining instead of calcium carbide.
Background
In the production process of iron and steel enterprises, reduction of production cost is always a continuous pursuit of the enterprises.
The chemical reactions of steel making occur primarily at the steel-slag interface. In the refining process of the LF furnace, the foamed slag is produced, so that the contact surface of the reaction can be increased, and the effects of improving the quality of molten steel, reducing the content of molten steel [ N ], improving the submerged arc effect and the like are obvious.
The calcium carbide is a foaming agent commonly used in the refining process of the LF furnace, and the main component of the calcium carbide is CaC2. The calcium carbide is easy to react with moisture in the air and decompose in the transportation and storage processes, so that the use effect of the calcium carbide is influenced, toxic gas CO is generated, and meanwhile, the calcium carbide is bagged and needs to be added manually by operators, so that the labor intensity of field operators is increased, and the production cost is increased.
Limestone can be decomposed at high temperature to generate CaO and CO2In which CaO is introduced into the slag as a slag-forming material, CO2The limestone is low in price and remarkable in submerged arc effect, and can be automatically added from a stock bin in feeding, so that the labor intensity of workers is reduced.
Therefore, the LF refining method for replacing calcium carbide with limestone has great economic and social benefits.
Disclosure of Invention
The invention aims to provide a method for applying limestone to LF refining instead of calcium carbide. The invention achieves the purposes of reducing the refining production cost of the molten steel LF furnace, improving the refining effect and reducing the labor intensity of workers.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for applying limestone to LF refining instead of calcium carbide comprises the steps of in the LF refining process, enabling molten steel to enter a station, switching on and opening bottom blowing argon after a steel ladle enters a working position, adding deoxidizing agents such as 0-0.7kg/t of steel aluminum particles, 0-0.8kg/t of steel calcium silicon powder and 0-1.0kg/t of steel silicon powder, adding 0-0.0 kg/t of lime and 2.0-3.0kg/t of limestone, stirring for 3-5min according to different steel types, adjusting argon flow, reducing electrodes to heat, and decomposing limestone by heating to generate CaO and CO2In which CaO is introduced into the slag as a slag-forming material, CO2Filled in the steel slag to play a foaming role and achieve the effect of submerged arc refining.
The station entering temperature of the molten steel is 1500-.
According to the invention, the bottom-blown argon gas is switched on and opened, and the flow of the bottom-blown argon gas is adjusted to be 100-300 Nm/h.
According to the invention, argon flow is adjusted to 50-100 Nm/h after stirring.
The electrode reduction heating method has the advantages that the initial heating time is 6-9min, and the temperature of molten steel is 1510-1550 ℃ after the heating is finished.
The method is suitable for smelting common deformed steel and cold heading steel.
The method provided by the invention is characterized in that a refined slag sample is taken for inspection after primary heating: CaO: 30-50% of SiO2：15-30%，MgO：5-15%，Al2O3：6-20%，FeO：1-2%，MnO：1-3%。
In the whole process of primary heating, the time for the poor submerged arc effect is 50-80 s.
The foaming principle of the calcium carbide is as follows: CaC2+3［O］=CaO+2CO
CaC2+3（FeO）=CaO+3Fe+2CO
The foaming principle of limestone is as follows: CaCO3=CaO+CO2
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. in the ladle refining process of the LF furnace, limestone is adopted to replace calcium carbide, the limestone is added in the early stage of refining, and the limestone is decomposed at high temperature to generate CaO and CO2In which CaO is introduced into the slag as a slag-forming material, CO2Filled in the steel slag, plays a foaming role and achieves the effect of submerged arc refining. 2. According to the invention, cheap limestone is used for replacing calcium carbide to carry out submerged arc refining, the submerged arc refining effect is obvious, the calcium carbide consumption is reduced by 0.5-0.8kg/t steel, the production cost is about 0.76-1.14 yuan/ton steel, and the cost is saved by more than 1.2 yuan per ton steel compared with the technical scheme of calcium carbide refining.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Based on a 100t converter system plain carbon steel LF refining furnace, limestone is used as a refining process of a foaming agent instead of calcium carbide.
TABLE 1 limestone composition
TABLE 2 calcium carbide composition
Example 1
The method for applying limestone to LF refining instead of calcium carbide is used in the LF furnace refining process of cold forging steel SWRCH22A, the weight of molten steel is 109t, and the steel enters the stationThe water temperature is 1540 ℃, after the steel ladle enters a working position, switching on and opening bottom-blown argon to regulate the argon flow to 200 Nm/h, adding 5.0kg/t of lime steel and 2.5kg/t of limestone steel, simultaneously adding 0.7kg/t of steel aluminum particles, 0kg/t of steel silico-calcium powder and 0kg/t of steel ferrosilicon powder deoxidizer, stirring for 3min, and then regulating the argon flow to 100 Nm/h; then, reducing the electrode for heating, wherein the primary heating time is 9min, the temperature of molten steel is 1550 ℃ after heating, taking a refined slag sample for inspection after primary heating, and the inspection result is as follows: CaO: 47.44% of SiO2：16.25%，MgO：10.41%，Al2O3: 19.81%, FeO: 1.2%, MnO: 1.4 percent; the time of poor submerged arc effect during the whole process of primary heating is the first 50 s.
Example 2
The method for applying limestone to LF refining instead of calcium carbide is used for the LF furnace refining process of cold forging steel SWRCH22A, the weight of molten steel is 108t, the temperature of the molten steel entering a station is 1538 ℃, after a ladle enters a working position, bottom blowing argon is switched on and opened to adjust the argon flow to 250 Nm/h, lime 4.5kg/t steel and limestone 2.5kg/t steel are added, meanwhile, 0.6kg/t aluminum particles of steel, 0kg/t silicon calcium powder of steel and 0kg/t silicon iron powder deoxidizer are added, and after 3min of stirring, the argon flow is adjusted to 50 Nm/h; then, reducing the electrode for heating, wherein the primary heating time is 9min, the temperature of molten steel is 1549 ℃ after heating, and a refined slag sample is taken for inspection after primary heating, and the inspection result is as follows: CaO: 46.95% of SiO2：16.48%，MgO：10.52%，Al2O3: 19.23%, FeO: 1.3%, MnO: 1.6 percent; the first 54s is the time of poor submerged arc throughout the initial heating.
Example 3
The method for applying limestone to LF refining instead of calcium carbide is used in the LF furnace refining process of deformed steel HRB400E, the weight of molten steel is 110t, the temperature of incoming molten steel is 1500 ℃, after a ladle enters a working position, bottom blowing argon is switched on and opened to adjust the argon flow to 150 Nm/h, lime 3.0kg/t steel and limestone 2.0kg/t steel are added, meanwhile, 0kg/t aluminum particles of steel, 0.5kg/t silicon calcium powder of steel and 1.0kg/t silicon iron powder deoxidizer are added, and after stirring for 3min, the argon flow is adjusted to 80 Nm/h; then lowering the electrode to heat, wherein the primary heating time is 7min,the temperature of molten steel is 1510 ℃ after heating, a refined slag sample is taken for inspection after primary heating, and the inspection result is as follows: CaO: 43.27% of SiO2：28.51%，MgO：12.7%，Al2O3: 6.52%, FeO: 1.43%, MnO: 2.42 percent; the first 75s is the time of poor submerged arc throughout the initial heating.
Example 4
The method for applying limestone to LF refining instead of calcium carbide is used in the LF furnace refining process of deformed steel HRB400E, the weight of molten steel is 104t, the temperature of incoming molten steel is 1502 ℃, after a ladle enters a working position, bottom blowing argon is switched on and opened to adjust the argon flow to 200 Nm/h, 3.5kg/t of steel and 2.0kg/t of limestone are added, 0kg/t of steel aluminum particles, 0.8kg/t of steel calcium silicon powder and 0.9kg/t of steel silicon iron powder deoxidizer are simultaneously added, and the argon flow is adjusted to 90 Nm/h after stirring for 3 min; then, reducing an electrode to heat, wherein the primary heating time is 8min, the molten steel temperature is 1515 ℃ after the heating is finished, and the refined slag sample is taken to be tested after the primary heating, and the test result is as follows: CaO: 44.74% of SiO2：27.64%，MgO：11.87%，Al2O3: 7.24%, FeO: 1.41%, MnO: 2.12 percent; the time for which the submerged arc effect is poor during the whole process of the primary heating is the first 80 s.
Example 5
The method for applying limestone to LF refining instead of calcium carbide is used for the LF furnace refining process of HPB300, the weight of molten steel is 107t, the temperature of incoming molten steel is 1529 ℃, after a ladle enters a working position, the ladle is communicated and opened to blow argon gas at the bottom to adjust the argon gas flow to 250 Nm/h, lime 4.0kg/t steel and limestone 3.0kg/t steel are added, meanwhile, 0.2kg/t aluminum particles of steel, 0.8kg/t silicon calcium powder of steel and 0.6kg/t silicon iron powder deoxidizer are added, and after stirring for 4min, the argon gas flow is adjusted to 90 Nm/h; then reducing the electrode to heat, wherein the primary heating time is 9min, the molten steel temperature is 1538 ℃ after heating, and the refined slag sample is taken to be tested after primary heating, and the test result is as follows: CaO: 40.25% of SiO2：24.86%，MgO：11.37%，Al2O3: 8.69%, FeO: 1.36%, MnO: 2.21 percent; the first 62s was the time of poor submerged arc throughout the initial heating.
Example 6
The method for applying limestone to LF refining instead of calcium carbide is used for the LF furnace refining process of HPB300, the weight of molten steel is 106t, the temperature of incoming molten steel is 1521 ℃, after a ladle enters a working position, the ladle is communicated and opened to blow argon gas at the bottom to adjust the argon gas flow to 240 Nm/h, lime 4.0kg/t steel and limestone 3.0kg/t steel are added, meanwhile, 0.2kg/t aluminum particles of steel, 0.8kg/t silicon calcium powder of steel and 0.6kg/t silicon iron powder deoxidizer are added, and after stirring for 4min, the argon gas flow is adjusted to 90 Nm/h; then, reducing the electrode for heating, wherein the primary heating time is 8min, the molten steel temperature is 1530 ℃ after heating, taking a refined slag sample for inspection after primary heating, and the inspection results are as follows: CaO: 41.51% of SiO2：23.72%，MgO：10.59%，Al2O3: 8.24%, FeO: 1.32%, MnO: 2.18 percent; the first 56s is the time when the submerged arc is less effective during the entire initial heating.
Example 7
The method for applying limestone to LF refining instead of calcium carbide is used in the LF furnace refining process of cold forging steel SWRCH22A, the weight of molten steel is 107t, the temperature of incoming molten steel is 1525 ℃, after a ladle enters a working position, bottom blowing argon is switched on and opened to adjust the argon flow to 100 Nm/h, lime 4.5kg/t steel and limestone 2.2kg/t steel are added, meanwhile, 0.2kg/t aluminum particles of steel, 0.5kg/t silico-calcium powder of steel and 0.3kg/t ferrosilicon powder deoxidizer are added, and after stirring for 5min, the argon flow is adjusted to 60 Nm/h; then, reducing the electrode for heating, wherein the primary heating time is 6min, the temperature of molten steel after heating is 1520 ℃, taking a refined slag sample for inspection after primary heating, and the inspection result is as follows: CaO: 50% of SiO2：20%，MgO：15%，Al2O3: 6%, FeO: 2%, MnO: 3 percent; the time of poor submerged arc effect during the whole process of primary heating is the first 60 s.
Example 8
The method for applying limestone to LF refining instead of calcium carbide is used in the LF furnace refining process of deformed steel bar HRB400E, the weight of molten steel is 106t, the temperature of the molten steel entering the station is 1534 ℃, after a ladle enters a working position, bottom-blowing argon is switched on and opened to adjust the argon flow to 300 Nm/h, lime 4.3kg/t steel and limestone 2.7kg/t steel are added, and meanwhile, 0.5kg/t steel aluminum particles are added,Stirring 0.6kg/t steel silico-calcium powder and 0.4kg/t steel ferrosilicon powder deoxidizer for 5min, and regulating argon flow to 70 Nm/h; then reducing the electrode to heat, heating for the first time for 7min, heating to reach the molten steel temperature of 1535 ℃, taking a refined slag sample after heating for the first time to test, wherein the test result is as follows: CaO: 30% of SiO2：30%，MgO：12%，Al2O3: 20%, FeO: 1.0%, MnO: 1.0 percent; the first 55s is the time of poor submerged arc effect during the whole process of the primary heating.
Example 9
The method for applying limestone to LF refining instead of calcium carbide is used for the LF furnace refining process of HPB300, the weight of molten steel is 108t, the temperature of incoming molten steel is 1516 ℃, after a ladle enters a working position, the ladle is communicated and opened to blow argon gas at the bottom to adjust the argon gas flow to 120 Nm/h, 3.3kg/t of steel and 2.7kg/t of steel of lime and 2.7kg/t of steel of limestone are added, meanwhile, 0.6kg/t of steel aluminum particles, 0.5kg/t of steel silico-calcium powder and 0.8kg/t of steel ferrosilicon powder deoxidizer are added, and after stirring for 4min, the argon gas flow is adjusted to 80 Nm/h; then, reducing an electrode to heat, wherein the primary heating time is 6min, the temperature of molten steel is 1528 ℃ after heating, and a refined slag sample is taken to be tested after primary heating, and the test result is as follows: CaO: 49.5% of SiO2：15%，MgO：5%，Al2O3: 19%, FeO: 1.5%, MnO: 2.5 percent; the first 58s was the time during which the submerged arc was less effective during the entire initial heating.
Comparative example 1
Taking an LF furnace refining process of deformed steel HRB400E as an example, the molten steel weight is 109t, the incoming molten steel temperature is 1538 ℃, after the molten steel enters a refining process, the argon flow is switched on and adjusted to 160 Nm/h, lime 3.5kg/t steel, silico-calcium powder 0.6kg/t steel, ferrosilicon powder 0.9kg/t steel and calcium carbide 0.6kg/t steel are added, after stirring for 3min, the argon flow is adjusted to 100 Nm/h, then electrode reduction heating is carried out, the initial heating time is 8min, the measured molten steel temperature is 1546 ℃ after heating is finished, the refined slag after initial heating is yellow and white slag, and sampling inspection is carried out, wherein the inspection results are as follows: CaO: 44.51% of SiO2：26.54%，MgO：11.9%，Al2O3: 7.41%, FeO: 1.37%, MnO: 1.95 percent; the first 71s is the time when the submerged arc is less effective during the entire initial heating.
TABLE 1 cost comparison tables for examples 1-9 and comparative example 1
Note: the other added materials have little influence on the cost and are ignored.
The following results were obtained by following the refining process of the LF furnace of the above examples and comparative examples: in examples 1-9, limestone is used as a foaming agent, calcium carbide is used as a foaming agent in a comparative example, and the limestone is used for replacing the calcium carbide to perform refining submerged arc with a similar effect, so that the effect of rapidly slagging and submerged arc operation is achieved, and meanwhile, data comparison in table 1 shows that the cost is reduced and the economic benefit is remarkable by applying the technical scheme of the method.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (2)
1. A method for applying limestone to LF refining instead of calcium carbide is characterized in that in the LF refining process, molten steel enters a station, a ladle enters a working position, the ladle is communicated and bottom-blown argon is opened, the argon flow is adjusted to be 300 Nm/h, 3.0-5.0kg/t of steel and 2.0-3.0kg/t of limestone are added, meanwhile, according to the difference of steel types, 0-0.7kg/t of aluminum particles of the steel, 0-0.8kg/t of silicon calcium powder of the steel and 0-1.0kg/t of silicon iron powder deoxidizer are added, the argon flow is adjusted to be 50-100 Nm/h after stirring for 3-5min, then electrodes are reduced for heating, the initial heating time is 6-9min, and the molten steel temperature is 1510-1550 ℃ after the heating is finished; taking a refined slag sample for inspection after primary heating: CaO: 30-50% of SiO2：15-30%，MgO：5-15%，Al2O3：6-20%，FeO：1-2%，MnO：1-3%；
The limestone component is CaCO3≥90%，SiO2 2-3%，Al2O3≤2%，MgCO3Less than or equal to 1.5 percent, less than or equal to 0.1 percent of S and less than or equal to 0.08 percent of P; the granularity is 6-10 mm;
in the whole process of primary heating, the time for poor submerged arc effect is 50-80 s;
the method is suitable for smelting common deformed steel and cold heading steel.
2. The method as claimed in claim 1, wherein the entering temperature of the molten steel is 1500-.
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