CN114717375B - Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting - Google Patents
Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting Download PDFInfo
- Publication number
- CN114717375B CN114717375B CN202210426710.5A CN202210426710A CN114717375B CN 114717375 B CN114717375 B CN 114717375B CN 202210426710 A CN202210426710 A CN 202210426710A CN 114717375 B CN114717375 B CN 114717375B
- Authority
- CN
- China
- Prior art keywords
- gun
- slag
- oxygen
- furnace
- controlled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000002893 slag Substances 0.000 title claims abstract description 92
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 73
- 238000000034 method Methods 0.000 title claims abstract description 54
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 35
- 238000003723 Smelting Methods 0.000 title claims abstract description 33
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 94
- 239000001301 oxygen Substances 0.000 claims abstract description 94
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 86
- 230000008569 process Effects 0.000 claims abstract description 35
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 34
- 239000010959 steel Substances 0.000 claims abstract description 34
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 30
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 30
- 239000004571 lime Substances 0.000 claims abstract description 30
- 235000019738 Limestone Nutrition 0.000 claims abstract description 24
- 239000006028 limestone Substances 0.000 claims abstract description 24
- 238000011049 filling Methods 0.000 claims abstract description 10
- 230000000630 rising effect Effects 0.000 claims abstract description 9
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 29
- 239000007788 liquid Substances 0.000 claims description 22
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 238000007664 blowing Methods 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 230000006872 improvement Effects 0.000 claims description 11
- 230000008859 change Effects 0.000 claims description 10
- 238000002844 melting Methods 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 230000014759 maintenance of location Effects 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 238000003763 carbonization Methods 0.000 claims description 3
- 230000008602 contraction Effects 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 3
- 239000000779 smoke Substances 0.000 claims description 3
- 229910052717 sulfur Inorganic materials 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000009628 steelmaking Methods 0.000 abstract description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 7
- 239000000428 dust Substances 0.000 description 7
- 239000003546 flue gas Substances 0.000 description 7
- 239000010459 dolomite Substances 0.000 description 4
- 229910000514 dolomite Inorganic materials 0.000 description 4
- 238000001035 drying Methods 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- 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
-
- 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
- C21C7/064—Dephosphorising; Desulfurising
-
- 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
- C21C7/064—Dephosphorising; Desulfurising
- C21C7/0645—Agents used for dephosphorising or desulfurising
-
- 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
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/40—Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The method mainly improves a slag making system, uses limestone to replace part of lime for slag making, controls the addition amount of lime to be 22-32 kg/t steel, controls the addition amount of limestone to be 8-15 kg/t steel, and solves the problems that the temperature rising speed of the converter smelting high-temperature molten iron is too high and the dephosphorization period of the converter is reduced due to the fact that lime is decomposed into endothermic reaction, a large amount of heat is absorbed, the filling system, the oxygen supplying system, the temperature system and the end point control are adaptively improved, the process steps and the process parameters of converter steelmaking are optimized, the initial temperature rising speed of the smelting is stable, the carbon-oxygen reaction period is prevented from arriving in advance, sufficient dephosphorization period time of the converter is ensured, and dephosphorization rate is ensured.
Description
Technical Field
The invention relates to the technical field of converter steelmaking, in particular to a method for smelting high-temperature molten iron by a converter under the conditions of slag remaining and dry dedusting.
Background
At present, a converter slag retaining process is adopted in converter steelmaking, wherein a part of the final slag of an upper furnace is retained for a lower furnace, the converter slag retaining process has the characteristics of large heat, high TFe content and capability of enabling the initial stage of the lower furnace to form slag rapidly, and the converter slag retaining process has the advantages of reducing slag forming material consumption, improving dephosphorization rate, reducing steel material consumption, reducing furnace lining erosion, improving furnace life and the like. At present, the temperature of molten iron used for converter steelmaking is higher, the average temperature of molten iron charged into the converter is 1378 ℃, the highest temperature of molten iron is 1450 ℃, and the higher temperature of molten iron is favorable for rapid slag formation and favorable for reducing the consumption of molten iron. At present, a dry dedusting process is adopted in converter steelmaking, in order to prevent 69 cross explosion in the blowing process, a half-oxygen mode is adopted after blowing, namely, the open-oxygen pressure is controlled to be 0.45-0.6 MPa, the oxygen pressure is gradually adjusted to be normal oxygen pressure within 90s, and the first slag making material is added after the half-oxygen period is finished. The dephosphorization reaction of the converter is exothermic, and the basic conditions of dephosphorization are as follows: high (FeO), high (CaO), high alkalinity, large slag amount, lower temperature, and good stirring dynamics condition.
The slag temperature left by the slag-leaving operation process is high, and the temperature of molten iron entering the furnace is high, so that the slag-leaving operation process is favorable for rapid slag formation, but has the following defects:
1) The slag-remaining temperature is high, the temperature of molten iron entering the furnace is high, and slag-forming materials cannot be added in the half-oxygen period, so that the initial temperature rise speed of a molten pool is high, the carbon-oxygen reaction period comes in advance, the dephosphorization reaction period time of the converter is shortened, and the dephosphorization rate is reduced;
according to calculation, the transition temperature of the dephosphorization reaction and the decarburization reaction of the converter is 1470 ℃, the dephosphorization reaction is mainly carried out when the temperature of a molten pool is less than 1470 ℃, and the speed of the carbon-oxygen reaction is increased when the temperature of the molten pool is more than 1470 ℃, so that the dephosphorization reaction is inhibited;
2) The fluctuation of the temperature rising rate in the smelting process is large, the smelting process is not well controlled, and the back drying or splashing is easy to occur;
3) In order to inhibit splashing in the steelmaking process, more lime is added in the smelting process.
Disclosure of Invention
The invention aims to provide a method for smelting high-temperature molten iron by a converter under the conditions of slag remaining and dry dedusting.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting comprises the improvement of a slag making system:
lime is used for replacing part of lime, the addition amount of lime is controlled to be 22-32 kg/t steel, and the addition amount of lime is controlled to be 8-15 kg/t steel;
after the half-oxygen period, when the oxygen pressure rises to normal, a first batch of slag making materials are added, 1/2-2/3 of the total lime amount, 2/3 of the total limestone amount and all grain steel are added, and the first batch of slag making materials are added within 2.5 minutes, so that the feeding process is continuous and uniform;
after the smelting medium period, adding the residual slag making materials in a mode of small batches, wherein 300-500kg of slag making materials are added to each batch, and the adding is completed within 8 min;
when the splash sign appears at the fast rising temperature in the middle smelting period, the gun is lifted to relieve the carbon-oxygen reaction, and 500-700kg of limestone is added in batches.
Preferably, improvement of the filling system:
the components of the molten iron in the furnace are as follows: 4.15 to 4.85 percent of C,0.30 to 0.60 percent of Si,0.35 to 0.50 percent of Mn,0.095 to 0.120 percent of P,0.012 to 0.040 percent of S, and the balance of Fe element and unavoidable impurities;
the temperature of the molten iron in the furnace is 1350-1450 ℃;
in the aspect of charge control, molten iron is controlled to be 110-120t, scrap steel is controlled to be 40-50t, total charge is controlled to be 155-160t, the furnace capacity ratio is controlled to be not lower than 0.9, and the scrap steel ratio is controlled to be not lower than 25%;
slag remaining amount control: 2-3t of slag is left in each furnace.
Preferably, the improvement of the oxygen supply system is as follows in time sequence:
3.1 Setting the oxygen pressure of the half oxygen mode to be 0.45-0.60MPa, and enabling the fan to be in a high-speed state;
3.2 The oxygen lance is lowered to a region of 2m-3m, and nitrogen is opened for 10-20s;
3.3 The oxygen lance is lowered to the position of 2.0m to open oxygen, and the oxygen lance is lowered to the position of 1.5m to observe the ignition condition;
3.4 If the lower lance is not ignited, waiting for 10-20s to observe whether the ignition is caused, if the ignition is caused after 20s, lowering the oxygen lance by 300-500mm to wait for 3-5s, lifting by 300-500mm to observe the ignition, and if the ignition is not caused, continuing to repeat the gun stringing action;
3.5 If the internal point is not ignited for 30s, the gun is required to be lifted immediately, the gun is started after the furnace is rocked forwards and backwards, the gun is started again, nitrogen with normal slag splashing pressure is blown into the furnace before the gun is started again, the oxygen concentration is ensured to be reduced to be within 15 percent, and the gun is switched to be started after the gun is positioned at a low position of 2000-2500 mm;
3.6 The ignition is still carried out again within 30 seconds, the gun lifting observation gun head is free from water leakage, a small amount of slag is poured out from the forward rocking furnace, the gun is ignited again, and the oxygen gun is lifted by 500-800mm immediately once being ignited in the ignition process;
3.7 After ignition is successful, the oxygen pressure is opened and blown at 0.40-0.50MPa, the oxygen pressure is gradually increased in 90s, and the oxygen pressure is automatically adjusted to 75 percent after 90s, so that the manual adjustment of the oxygen pressure is resumed;
3.8 After the first batch of slag forming materials are added, when the concentration of CO is more than 10%, lifting a gun to form slag with the thickness of 200mm-300mm, and reducing the oxygen pressure to 0.8MPa-0.85MPa;
3.9 After primary slagging is finished, gradually lowering the lance to 1.2-1.4 m from the liquid level after observing the flame contraction at the furnace mouth to shake and throwing slag sheets;
3.10 In the blowing process, referring to CO concentration change, an audio slag melting curve and furnace mouth flame change to adjust gun positions, when the CO concentration continuously rises, the audio slag melting curve goes down, and the furnace mouth flame is hardened, timely lifting the gun by 100-300mm or reducing oxygen pressure to 0.8MPa, otherwise, lowering the gun by 100-300mm or increasing oxygen pressure to 0.85-0.88MPa, wherein the lowest gun position distance in the blowing process is more than 1.2m-1.3m from the liquid level;
3.11 When the gun is 1.2-1.5m away from the liquid surface in the blowing process, lifting the gun until the fire is received to shorten the time for returning the dry when the condition of returning the dry occurs, and lowering the gun to 1.3-1.5m away from the liquid surface in time after the fire is received to prevent splashing;
3.12 When splashing occurs, the gun position is increased by 200-400m, the pressure is reduced to 0.75-0.80MPa, the molten pool reaction is relieved, and 500-700kg of limestone or dolomite is added in batches;
3.13 1.5-2min before the end point, lifting the gun to 2.0-2.5m from the liquid level, removing slag, lifting the gun for the heat treatment, collecting fire, lifting the movable smoke hood to the upper limit, and staying for 20-50s to ensure that the slag is thoroughly removed;
3.14 After the carbonization, the carbon gun is lowered to a carbon gun drawing position in 4 stages: the first stage descending gun stays for 20s at 400mm, the second stage descending gun stays for 10s at 200mm, the third stage descending gun stays for 10s at 150mm, the fourth stage descending gun stays for 10-20s at 100mm, and the carbon gun is at a position 1.0m from the liquid level at the end point;
3.15 The final pressure gun time is more than 15s, and the oxygen pressure is 0.9-1.0MPa.
Preferably, improvement of end point control:
the final lance pressing time is more than 15s, the oxygen pressure is 0.9-1.0MPa, the final molten steel temperature is controlled at 1610-1660 ℃, the final C content is controlled at 0.07-0.13%, and the final P content is controlled at less than or equal to 0.037%.
Preferably, in the slagging system, in the middle smelting period, the slagging material is added when the slag condition in the furnace is good, and the slagging material is added when the flame at the furnace mouth shakes, the CO concentration is stable or has a descending trend, and the audio slagging curve is in a red zone and is upwards.
The application achieves the following beneficial technical effects:
1) According to the method, a slagging system is mainly improved, limestone is used for replacing part of lime for slagging, the addition amount of lime is controlled to be 22-32 kg/t steel, and the addition amount of limestone is controlled to be 8-15 kg/t steel, because limestone is decomposed into lime which is subjected to endothermic reaction, a large amount of heat is absorbed, and the filling system, the oxygen supply system, the temperature system and the end point control are adaptively improved, so that the process steps and the process parameters of converter steelmaking are optimized, the stable temperature rising speed in the initial smelting stage is ensured, the early arrival of a carbon-oxygen reaction period is prevented, the sufficient dephosphorization period time of a converter is ensured, the dephosphorization rate is ensured, and the problems that the temperature rising speed in the initial smelting stage is too fast and the dephosphorization rate of the converter is reduced under the conditions of slag remaining and dry dedusting are successfully realized.
2) In the present application, limestone is decomposed in a converter to produce CO 2 The gas plays a certain stirring role on the molten pool, so that the melting of the slag forming material is quickened.
3) In the method, limestone is used for replacing part of lime for slagging, so that lime consumption can be reduced by 5-10 Kg/ton of steel, and production cost is reduced.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The application provides a method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting, which is characterized in that the slag making system is improved:
lime is used for replacing part of lime, the addition amount of lime is controlled to be 22-32 kg/t steel, and the addition amount of lime is controlled to be 8-15 kg/t steel;
after the half-oxygen period, when the oxygen pressure rises to normal, a first batch of slag making materials are added, 1/2-2/3 of the total lime amount, 2/3 of the total limestone amount and all grain steel are added, and the first batch of slag making materials are added within 2.5 minutes, so that the feeding process is continuous and uniform;
after the smelting medium period, adding the residual slag making materials in a mode of small batches according to the process temperature condition and the slag melting condition, wherein 300-500kg of slag making materials are added in each batch, and the adding is completed within 8 min;
when the splash sign appears at the fast rising temperature in the middle smelting period, the gun is lifted to relieve the carbon-oxygen reaction, and 500-700kg of limestone is added in batches.
In one embodiment of the present application, improvements in the loading regime:
the components of the molten iron in the furnace are as follows: 4.15 to 4.85 percent of C,0.30 to 0.60 percent of Si,0.35 to 0.50 percent of Mn,0.095 to 0.120 percent of P,0.012 to 0.040 percent of S, and the balance of Fe element and unavoidable impurities;
the temperature of the molten iron in the furnace is 1350-1450 ℃;
in the aspect of charge control, molten iron is controlled to be 110-120t, scrap steel is controlled to be 40-50t, total charge is controlled to be 155-160t, the furnace capacity ratio is controlled to be not lower than 0.9, and the scrap steel ratio is controlled to be not lower than 25%;
slag remaining amount control: 2-3t of slag is left in each furnace.
In one embodiment of the present application, the improvement of the oxygen supply system is as follows in time sequence:
3.1 Setting the oxygen pressure of the half oxygen mode to be 0.45-0.60MPa, and enabling the fan to be in a high-speed state;
3.2 The oxygen lance is lowered to a 3m-2m area, and nitrogen is opened for 10-20s;
3.3 The oxygen lance is lowered to the position of 2.0m to open oxygen, and the oxygen lance is lowered to the position of 1.5m to observe the ignition condition;
3.4 If the lower lance is not ignited, waiting for 10-20s to observe whether the ignition is caused, if the ignition is caused after 20s, lowering the oxygen lance by 300-500mm to wait for 3-5s, lifting by 300-500mm to observe the ignition, and if the ignition is not caused, continuing to repeat the gun stringing action;
3.5 If the internal point is not ignited for 30s, the gun is required to be lifted immediately, the gun is started after the furnace is rocked forwards and backwards, the gun is started again, nitrogen with normal slag splashing pressure is blown into the furnace before the gun is started again, the oxygen concentration is ensured to be reduced to be within 15 percent, and the gun is switched to be started after the gun is positioned at a low position of 2000-2500 mm;
3.6 The ignition is still carried out again within 30 seconds, the gun lifting observation gun head is free from water leakage, a small amount of slag is poured out from the forward rocking furnace, the gun is ignited again, and the oxygen gun is lifted by 500-800mm immediately once being ignited in the ignition process;
3.7 After ignition is successful, the oxygen pressure is opened and blown at 0.40-0.50MPa, the oxygen pressure is gradually increased in 90s, and the oxygen pressure is automatically adjusted to 75 percent after 90s, so that the manual adjustment of the oxygen pressure is resumed;
3.8 After the first batch of slag forming materials are added, when the concentration of CO is more than 10%, lifting a gun to form slag with the thickness of 200mm-300mm, and reducing the oxygen pressure to 0.8MPa-0.85MPa;
3.9 After primary slagging is finished, gradually lowering the lance to 1.2-1.4 m from the liquid level after observing the flame contraction at the furnace mouth to shake and throwing slag sheets;
3.10 In the blowing process, referring to CO concentration change, an audio slag melting curve and furnace mouth flame change to adjust gun positions, when the CO concentration continuously rises, the audio slag melting curve goes down, and the furnace mouth flame is hardened, timely lifting the gun by 100-300mm or reducing oxygen pressure to 0.8MPa, otherwise, lowering the gun by 100-300mm or increasing oxygen pressure to 0.85-0.88MPa, wherein the lowest gun position distance in the blowing process is more than 1.2m-1.3m from the liquid level;
3.11 When the gun is 1.2-1.5m away from the liquid surface in the blowing process, lifting the gun until the fire is received to shorten the time for returning the dry when the condition of returning the dry occurs, and lowering the gun to 1.3-1.5m away from the liquid surface in time after the fire is received to prevent splashing;
3.12 When splashing occurs, the gun position is increased by 200-400m, the pressure is reduced to 0.75-0.80MPa, the molten pool reaction is relieved, and 500-700kg of limestone or dolomite is added in batches;
3.13 1.5-2min before the end point, lifting the gun to 2.0-2.5m from the liquid level, removing slag, lifting the gun for the heat treatment, collecting fire, lifting the movable smoke hood to the upper limit, and staying for 20-50s to ensure that the slag is thoroughly removed;
3.14 After the carbonization, the carbon gun is lowered to a carbon gun drawing position in 4 stages: the first stage descending gun stays for 20s at 400mm, the second stage descending gun stays for 10s at 200mm, the third stage descending gun stays for 10s at 150mm, the fourth stage descending gun stays for 10-20s at 100mm, and the carbon gun is at a position 1.0m from the liquid level at the end point;
3.15 The final pressure gun time is more than 15s, and the oxygen pressure is 0.9-1.0MPa.
In one embodiment of the present application, improvement of endpoint control:
the final lance pressing time is more than 15s, the oxygen pressure is 0.9-1.0MPa, the final molten steel temperature is controlled at 1610-1660 ℃, the final C content is controlled at 0.07-0.13%, and the final P content is controlled at less than or equal to 0.037%.
In one embodiment of the application, in the middle smelting period, the slag making material is added when the slag condition in the furnace is good, and the slag making material is added when the flame at the furnace mouth shakes, the CO concentration is stable or has a descending trend, and the audio slag making curve is in a red zone and is upwards biased.
In this application, improvement of temperature regime: aiming at the actual situation of high temperature of molten iron and slag-reserving operation, the first batch of slag-making materials is added with 2/3 of the total amount of all grain steel and limestone, so that the carbon-oxygen reaction is prevented from proceeding in advance due to the excessively high temperature rising speed of a molten pool.
In the application, the dry dust removal refers to dry dust removal of primary flue gas of a converter; the primary flue gas of the converter refers to flue gas directly coming out of a flue in the oxygen blowing and converting process of the converter, has serious pollution, contains a large amount of coal gas, and has the characteristics of high temperature, toxicity, inflammability, explosiveness, high dust content and the like; the secondary flue gas of the converter is the flue gas overflowed from the fume hood during the oxygen blowing period of the converter and the flue gas generated during the activities of steel mixing, tapping and the like; at present, the dust removal method of primary flue gas of the converter mainly comprises dry dust removal (LT), OG wet dust removal and semi-dry dust removal.
The content (%) in the present application is mass percent.
The method and the device which are not described in detail in the invention are all the prior art and are not described in detail.
In order to further understand the present invention, the method for smelting high-temperature molten iron in a converter under the conditions of slag-reserving and dry dedusting provided by the present invention is described in detail below with reference to examples, and the scope of protection of the present invention is not limited by the following examples.
Example 1
Embodiment 1 provides a method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting, which comprises the following steps:
1) Filling system:
the molten iron temperature is 1413 ℃, the molten iron component is C4.68%, si 0.41%, mn 0.46%, P0.101% and S0.018%. The filling amount of molten iron 116.13t, the scrap steel 41.70t and the total filling amount 157.83t;
the heat has about 2t of slag left by the previous heat;
2) Slag making system:
3.1 After the half-oxygen period is over, adding 2005kg of lime, 1306kg of limestone, all grain steel and 2195kg of light burned dolomite;
3.2 After entering the middle smelting stage, 1106kg of lime is added for four times, 3111kg of lime is added in total, and the total amount is 21.16kg/t of steel;
3.3 Blowing for 6 minutes, adding 440kg of limestone in two times, wherein 1746kg of limestone is added in the furnace, and the total amount of the limestone is reduced to 11.88kg/t of steel;
3) Oxygen supply system:
3.1 The oxygen lance nozzle used is a five-hole Laval nozzle, and the diameter of the throat is 40.8mm;
3.2 The oxygen lance is lowered to a region of 2m-3m, and nitrogen is opened for 15s;
3.3 The oxygen lance is lowered to the position of 2.0m to open oxygen, the oxygen lance is lowered to the position of 1.5m to observe the ignition condition, the ignition is normal, and the oxygen lance is gradually lowered to the position of 1.2m;
3.4 After ignition is successful, the oxygen pressure in the blowing-on 90s is gradually increased to 0.92MPa;
3.5 After the first batch of slag forming materials are added, when the concentration of CO is 13%, lifting a gun to 200mm to form slag, and reducing the oxygen pressure to 0.82MPa;
3.6 After primary slagging is finished, when the flame at the furnace mouth is observed to shrink and shake, slag sheets are thrown out, the gun is lowered to 1.3m from the liquid level;
3.7 The gun position is flexibly adjusted by referring to the CO concentration change and the audio slag melting curve and combining with the flame change of the furnace mouth, the gun position is controlled to be 1.3-1.5m from the liquid level, the gun is lifted to be 1.7m for about 15s when the smelting process is carried out for 8 minutes, the dry return is prevented, and no splash exists in the smelting process;
3.8 End-point gun time 21s, oxygen pressure 0.95MPa;
4) Temperature system: the temperature is raised normally in the smelting process, and no splashing and no drying back are caused;
5) Endpoint control: endpoint component C0.067%, mn 0.209%, P0.0287%, S0.0179%, carbon pulling temperature 1621 ℃.
Example 2
Example 2 provides a method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting, which comprises the following steps:
1) Filling system:
molten iron temperature 1447 ℃, molten iron component C4.58%, si 0.41%, mn 0.77%, P0.106%, S0.025%. The filling amount of molten iron 114.58t, the scrap steel 41.65t and the total filling amount 156.23t;
the heat has about 2t of slag left by the previous heat;
2) Slag making system:
2.1 2315kg of lime, 1213kg of limestone, all grain steel and 2075kg of light burned dolomite are added after the half oxygen period is finished;
2.2 After entering the middle smelting stage, adding 1144kg of lime four times, adding 3459kg of lime in total, and folding 23.37kg/t steel;
2.3 Blowing for 6.5 minutes, adding 597kg of limestone in two times, wherein 1810kg of limestone is added in the furnace, and the total amount of the furnace is reduced to 12.23kg/t of steel;
3) Oxygen supply system:
3.1 The oxygen lance nozzle used is a five-hole Laval nozzle, and the diameter of the throat is 40.8mm;
3.2 The oxygen lance is lowered to a region of 2m-3m, and nitrogen is opened for 18s;
3.3 The oxygen lance is lowered to the position of 2.0m to open oxygen, the oxygen lance is lowered to the position of 1.5m to observe the ignition condition, the ignition is normal, and the oxygen lance is gradually lowered to the position of 1.3m;
3.4 After ignition is successful, the oxygen pressure in the blowing-on 90s is gradually increased to 0.91MPa;
3.5 After the first batch of slag forming materials are added, when the concentration of CO is 12%, lifting a gun to 200mm to form slag, and reducing the oxygen pressure to 0.84MPa;
3.6 After primary slagging is finished, when the flame at the furnace mouth is observed to shrink and shake, slag sheets are thrown out, the gun is lowered to 1.3m from the liquid level;
3.7 The gun position is flexibly adjusted by referring to the CO concentration change and the audio slag melting curve and combining with the flame change of the furnace mouth, the gun position is controlled to be 1.3-1.5m from the liquid level in the process, and no dry return and no splash are generated in the smelting process;
4) Temperature system: the temperature of the furnace is normally raised in the process of the heat treatment, no return drying and no splashing are caused;
5) Endpoint control: endpoint component C0.089%, mn 0.279%, P0.0306%, S0.0227%, and carbon pulling temperature 1639 ℃.
The above description of the embodiments is only for aiding in the understanding of the method of the present invention and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.
Claims (2)
1. A method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting is characterized by improving a slag making system:
lime is used for replacing part of lime, the addition amount of lime is controlled to be 22-32 kg/t steel, and the addition amount of lime is controlled to be 8-15 kg/t steel;
after the half-oxygen period, when the oxygen pressure rises to normal, a first batch of slag making materials are added, 1/2-2/3 of the total lime amount, 2/3 of the total limestone amount and all grain steel are added, and the first batch of slag making materials are added within 2.5 minutes, so that the feeding process is continuous and uniform;
after the smelting medium period, adding the residual slag making materials in a mode of small batches, wherein 300-500kg of slag making materials are added to each batch, and the adding is completed within 8 min;
when the splash sign appears at the fast rising temperature in the middle smelting period, the gun is lifted to relieve the carbon-oxygen reaction, and 500-700kg of limestone is added in batches;
improvement of filling system:
the components of the molten iron in the furnace are as follows: 4.15 to 4.85 percent of C,0.30 to 0.60 percent of Si,0.35 to 0.50 percent of Mn,0.095 to 0.120 percent of P,0.012 to 0.040 percent of S, and the balance of Fe element and unavoidable impurities;
the temperature of the molten iron in the furnace is 1350-1450 ℃;
in the aspect of charge control, molten iron is controlled to be 110-120t, scrap steel is controlled to be 40-50t, total charge is controlled to be 155-160t, the furnace capacity ratio is controlled to be not lower than 0.9, and the scrap steel ratio is controlled to be not lower than 25%;
slag remaining amount control: 2-3t of slag is left in each furnace;
the improvement of the oxygen supply system is as follows in sequence according to time:
3.1 Setting the oxygen pressure of the half oxygen mode to be 0.45-0.60MPa, and enabling the fan to be in a high-speed state;
3.2 The oxygen lance is lowered to a region of 2m-3m, and nitrogen is opened for 10-20s;
3.3 The oxygen lance is lowered to the position of 2.0m to open oxygen, and the oxygen lance is lowered to the position of 1.5m to observe the ignition condition;
3.4 If the lower lance is not ignited, waiting for 10-20s to observe whether the ignition is caused, if the ignition is caused after 20s, lowering the oxygen lance by 300-500mm to wait for 3-5s, lifting by 300-500mm to observe the ignition, and if the ignition is not caused, continuing to repeat the gun stringing action;
3.5 If the internal point is not ignited for 30s, the gun is required to be lifted immediately, the gun is started after the furnace is rocked forwards and backwards, the gun is started again, nitrogen with normal slag splashing pressure is blown into the furnace before the gun is started again, the oxygen concentration is ensured to be reduced to be within 15 percent, and the gun is switched to be started after the gun is positioned at a low position of 2000-2500 mm;
3.6 The ignition is still carried out again within 30 seconds, the gun lifting observation gun head is free from water leakage, a small amount of slag is poured out from the forward rocking furnace, the gun is ignited again, and the oxygen gun is lifted by 500-800mm immediately once being ignited in the ignition process;
3.7 After ignition is successful, the oxygen pressure is opened and blown at 0.40-0.50MPa, the oxygen pressure is gradually increased in 90s, and the oxygen pressure is automatically adjusted to 75 percent after 90s, so that the manual adjustment of the oxygen pressure is resumed;
3.8 After the first batch of slag forming materials are added, when the concentration of CO is more than 10%, lifting a gun to form slag with the thickness of 200mm-300mm, and reducing the oxygen pressure to 0.8MPa-0.85MPa;
3.9 After primary slagging is finished, gradually lowering the lance to 1.2-1.4 m from the liquid level after observing the flame contraction at the furnace mouth to shake and throwing slag sheets;
3.10 In the blowing process, referring to CO concentration change, an audio slag melting curve and furnace mouth flame change to adjust gun positions, when the CO concentration continuously rises, the audio slag melting curve goes down, and the furnace mouth flame is hardened, timely lifting the gun by 100-300mm or reducing oxygen pressure to 0.8MPa, otherwise, lowering the gun by 100-300mm or lifting oxygen pressure to 0.85-0.88MPa, wherein the lowest gun position distance liquid level in the blowing process is more than 1.2m and less than or equal to 1.3m;
3.11 When the gun is 1.2-1.5m away from the liquid surface in the blowing process, lifting the gun until the fire is received to shorten the time for returning the dry when the condition of returning the dry occurs, and lowering the gun to 1.3-1.5m away from the liquid surface in time after the fire is received to prevent splashing;
3.12 When splash occurs, the gun position is increased by 200-400m, the pressure is reduced to 0.75-0.80MPa, the molten pool reaction is relieved, and 500-700kg of limestone is added in batches;
3.13 1.5-2min before the end point, lifting the gun to 2.0-2.5m from the liquid level, removing slag, lifting the gun for the heat treatment, collecting fire, lifting the movable smoke hood to the upper limit, and staying for 20-50s to ensure that the slag is thoroughly removed;
3.14 After the carbonization, the carbon gun is lowered to a carbon gun drawing position in 4 stages: the first stage descending gun stays for 20s at 400mm, the second stage descending gun stays for 10s at 200mm, the third stage descending gun stays for 10s at 150mm, the fourth stage descending gun stays for 10-20s at 100mm, and the carbon gun is at a position 1.0m from the liquid level at the end point;
3.15 The final pressure gun time is more than 15s, and the oxygen pressure is 0.9-1.0MPa;
improvement of end point control:
the final lance pressing time is more than 15s, the oxygen pressure is 0.9-1.0MPa, the final molten steel temperature is controlled at 1610-1660 ℃, the final C content is controlled at 0.07-0.13%, and the final P content is controlled at less than or equal to 0.037%.
2. The method for smelting high-temperature molten iron by a converter under the conditions of slag retention and dry dedusting as claimed in claim 1, wherein in the slagging system, the slagging material is added when the slag condition in the converter is good in the middle smelting period, and the slagging material is added when the flame at the furnace mouth shakes, the CO concentration is stable or has a descending trend, and the audio slagging curve is in a red zone and is upwards inclined.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210426710.5A CN114717375B (en) | 2022-04-22 | 2022-04-22 | Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210426710.5A CN114717375B (en) | 2022-04-22 | 2022-04-22 | Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114717375A CN114717375A (en) | 2022-07-08 |
| CN114717375B true CN114717375B (en) | 2024-02-27 |
Family
ID=82246652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210426710.5A Active CN114717375B (en) | 2022-04-22 | 2022-04-22 | Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114717375B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115404300B (en) * | 2022-09-09 | 2023-12-08 | 山东莱钢永锋钢铁有限公司 | Control method for converter bottom thickness |
| CN115404301B (en) * | 2022-09-09 | 2024-02-27 | 山东莱钢永锋钢铁有限公司 | Method for preventing explosion venting of converter dry dedusting system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107099638A (en) * | 2017-05-19 | 2017-08-29 | 山东钢铁股份有限公司 | It is a kind of to prevent dry method dust converter from opening to be blown off quick-fried control method |
| CN108411060A (en) * | 2018-06-14 | 2018-08-17 | 宝钢湛江钢铁有限公司 | A kind of method of coverter pig slagging with Lime stone steel-making control of lance position |
| CN114231686A (en) * | 2021-11-26 | 2022-03-25 | 山东钢铁集团永锋临港有限公司 | Method for smelting with less slag left under converter dry dedusting process condition |
-
2022
- 2022-04-22 CN CN202210426710.5A patent/CN114717375B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107099638A (en) * | 2017-05-19 | 2017-08-29 | 山东钢铁股份有限公司 | It is a kind of to prevent dry method dust converter from opening to be blown off quick-fried control method |
| CN108411060A (en) * | 2018-06-14 | 2018-08-17 | 宝钢湛江钢铁有限公司 | A kind of method of coverter pig slagging with Lime stone steel-making control of lance position |
| CN114231686A (en) * | 2021-11-26 | 2022-03-25 | 山东钢铁集团永锋临港有限公司 | Method for smelting with less slag left under converter dry dedusting process condition |
Non-Patent Citations (2)
| Title |
|---|
| 张飞 ; .石灰石在莱钢120t转炉炼钢中应用实践.中国冶金.2015,(第03期),第37-40页. * |
| 谢基表 ; 闫海龙 ; 鲍生科 ; 刘守杰 ; 王哲 ; .转炉石灰石直接造渣炼钢工艺研究.河北冶金.2018,(第07期),第18-21页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114717375A (en) | 2022-07-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114717375B (en) | Method for smelting high-temperature molten iron by converter under conditions of slag remaining and dry dedusting | |
| US4988079A (en) | Apparatus for smelting and reducing iron ores | |
| JP5440733B2 (en) | Hot metal refining method | |
| CN113493868B (en) | High scrap ratio converter smelting method based on molten reduced molten iron | |
| CN112708717A (en) | Method for smelting low-phosphorus molten steel by single-converter duplex method | |
| CN113817888A (en) | Optimized smelting method for converter slag remaining operation | |
| CN108842027B (en) | Gasification dephosphorization method and smelting method for final slag of dephosphorization converter | |
| CN110564908A (en) | double-slag dephosphorization and steel-making method for semisteel converter | |
| JP6361885B2 (en) | Hot metal refining method | |
| CN114058771A (en) | Slag charging converter steelmaking method capable of reducing early-stage slag overflow | |
| CN113278765A (en) | Desulfurizing agent for converter and desulfurizing method | |
| CN111363882A (en) | Slagging method for prolonging service life of converter lining | |
| JP2803528B2 (en) | Converter steelmaking method | |
| JP7136390B1 (en) | Molten iron smelting method | |
| JP5949627B2 (en) | Method of refining hot metal in converter | |
| CN114292983B (en) | Production method of high-phosphorus steel | |
| CN110551871B (en) | Smelting method capable of shortening smelting period of Consteel electric furnace | |
| RU2389800C1 (en) | Procedure for combined process of charge of slag scull with melting steel in converter at reduced consumption of iron | |
| JPH0437135B2 (en) | ||
| CN117568548A (en) | Method for smelting converter full molten iron under dry dedusting condition | |
| JPH11181513A (en) | Method for melting iron-containing cold material | |
| JPH0433844B2 (en) | ||
| JP6327298B2 (en) | Hot metal refining method | |
| CN116926264A (en) | Furnace lining maintenance method in converter slag-less smelting mode | |
| CN115679032A (en) | Converter steelmaking method by single-slag deep desulfurization |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |