CN117535469A - Method for maintaining furnace conditions in low iron loss mode - Google Patents
Method for maintaining furnace conditions in low iron loss mode Download PDFInfo
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- CN117535469A CN117535469A CN202311528830.7A CN202311528830A CN117535469A CN 117535469 A CN117535469 A CN 117535469A CN 202311528830 A CN202311528830 A CN 202311528830A CN 117535469 A CN117535469 A CN 117535469A
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 100
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 31
- 239000002893 slag Substances 0.000 claims abstract description 153
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 53
- 239000010959 steel Substances 0.000 claims abstract description 53
- 238000007664 blowing Methods 0.000 claims abstract description 33
- 238000003723 Smelting Methods 0.000 claims abstract description 29
- 239000000463 material Substances 0.000 claims abstract description 29
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 28
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 28
- 230000000694 effects Effects 0.000 claims abstract description 28
- 239000004571 lime Substances 0.000 claims abstract description 28
- 238000002844 melting Methods 0.000 claims abstract description 13
- 230000008018 melting Effects 0.000 claims abstract description 13
- 230000003628 erosive effect Effects 0.000 claims abstract description 9
- 238000005496 tempering Methods 0.000 claims abstract description 8
- 238000005502 peroxidation Methods 0.000 claims abstract description 7
- 238000010791 quenching Methods 0.000 claims abstract description 7
- 230000000171 quenching effect Effects 0.000 claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 7
- 238000004364 calculation method Methods 0.000 claims abstract description 6
- 238000010079 rubber tapping Methods 0.000 claims abstract description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 32
- 239000001301 oxygen Substances 0.000 claims description 32
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 29
- 238000003825 pressing Methods 0.000 claims description 29
- 239000002956 ash Substances 0.000 claims description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 12
- 229910052799 carbon Inorganic materials 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 11
- 238000006477 desulfuration reaction Methods 0.000 claims description 11
- 230000023556 desulfurization Effects 0.000 claims description 11
- 229910052710 silicon Inorganic materials 0.000 claims description 11
- 239000010703 silicon Substances 0.000 claims description 11
- 239000010882 bottom ash Substances 0.000 claims description 6
- 238000007599 discharging Methods 0.000 claims description 6
- 150000002978 peroxides Chemical class 0.000 claims description 6
- 238000009991 scouring Methods 0.000 claims description 6
- 239000003245 coal Substances 0.000 claims description 5
- XWHPIFXRKKHEKR-UHFFFAOYSA-N iron silicon Chemical compound [Si].[Fe] XWHPIFXRKKHEKR-UHFFFAOYSA-N 0.000 claims description 5
- 238000012423 maintenance Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 5
- 230000002035 prolonged effect Effects 0.000 claims description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 4
- 229910052698 phosphorus Inorganic materials 0.000 claims description 4
- 239000011574 phosphorus Substances 0.000 claims description 4
- 230000008719 thickening Effects 0.000 claims description 4
- 229910000514 dolomite Inorganic materials 0.000 claims description 3
- 239000010459 dolomite Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- 230000002265 prevention Effects 0.000 abstract 1
- 238000004904 shortening Methods 0.000 abstract 1
- 230000008569 process Effects 0.000 description 11
- 230000006872 improvement Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 125000002081 peroxide group Chemical group 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000033764 rhythmic process Effects 0.000 description 1
- 238000009628 steelmaking Methods 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
- 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
- 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
-
- 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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- Engineering & Computer Science (AREA)
- 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 steel smelting, and particularly relates to a method for maintaining furnace conditions in a low-iron-loss mode. The method comprises the following steps: (1) directly tapping after the blowing of the non-pouring furnace is finished; (2) extending the end-point gun duration; (3) Preparing a slag-making material proportion table for slag-making smelting in a low iron loss mode according to a converter lime addition amount calculation formula, and carrying out slag-making smelting; (4) making measures for preventing the sticking of scrap steel; (5) Adding deoxidizing substances into the peroxidation heat to carry out quenching and tempering treatment on the slag; (6) improving the slag charge ratio. The invention reduces the FeO content in slag, thereby improving the erosion resistance of a slag layer of a furnace lining, improving the slag splashing furnace protection effect of a converter, being beneficial to prolonging the service life of the furnace lining, shortening the tapping time, preventing the temperature drop, and reducing the link frequency of scrap steel and iron blocks which are adhered by melting of a pouring furnace by making scrap steel prevention measures.
Description
Technical Field
The invention belongs to the technical field of steel smelting, and particularly relates to a method for maintaining furnace conditions in a low-iron-loss mode.
Background
In order to improve the steelmaking capacity, a production mode with low iron loss and fast rhythm is adopted under the condition that the blast furnace capacity is certain in a steel plant, the smelting period of a converter is controlled within 27 minutes, and the iron loss is controlled below 750 kg/t. In the low-iron-loss production mode, the number of the terminal peroxide heats is more, the corrosion of the furnace lining is aggravated, and the maintenance of the furnace condition is not facilitated. The main problems are as follows:
firstly, after converter blowing is finished, the temperature measurement and sampling are carried out by pouring the converter, the time is about 3 minutes, the temperature drop loss in the process is 15-30 ℃, the steel placing temperature needs to be increased, and the maintenance of a furnace lining is not facilitated.
Secondly, the FeO content in the terminal slag is higher, the slag splashing furnace protection effect is poor, the slag layer meltability temperature is low, and the scouring erosion is not resisted in the smelting process. From the data of the lining measurement, the lining erosion is faster. For example, in the case of a 772-furnace with a furnace life, the front face has an average thickness of 614mm and a minimum thickness of 564mm. In the case of a 3585 furnace of age only, the front face lining thickness has an average value of 705mm and a minimum value of 561mm.
Thirdly, under the condition of terminal peroxidation, slag is foamed in the steel discharging process, slag is easy to be discharged from a large furnace mouth, the slag quantity in the furnace is reduced when slag is splashed, the slag splashing furnace protection effect of the converter is affected, and a slag splashing layer with a certain thickness is not formed easily.
And in the production mode of low iron loss, the addition amount of scrap steel is larger, the frequency of sticking scrap steel and iron blocks on the furnace lining is more, and the iron blocks and scrap steel adhered to the furnace lining in the later stage are melted and absorb a large amount of heat, so that the terminal temperature is lower, the temperature is raised by blowing, the oxidizing property of molten steel is increased, and the corrosion of the furnace lining is increased.
Disclosure of Invention
The invention aims to provide a method for maintaining furnace conditions in a low iron loss mode, which aims to solve the problems in the prior art.
The technical scheme adopted for solving the technical problems is as follows: a method of furnace condition maintenance in a low iron loss mode, comprising the steps of:
(1) Directly tapping after the blowing of the non-pouring furnace is finished;
(2) The gun pressing time at the end point is prolonged;
(3) Preparing a slag-making material proportion table for slag-making smelting in a low iron loss mode according to a converter lime addition amount calculation formula, and carrying out slag-making smelting;
(4) Making measures for preventing steel scrap sticking;
(5) Adding deoxidizing substances into the peroxidation heat to carry out quenching and tempering treatment on the slag;
(6) Improving the slag pressing material proportion.
Further, after the blowing of the non-pouring furnace in the step (1) is finished, the steel is directly tapped, and a T-C-O bullet type sublance control system is adopted at the end of the blowing to judge the temperature of the end point, the carbon content of molten steel and the phosphorus content of molten steel, so that an operator can control the time for stopping the blowing according to the measurement result of the bullet type sublance, and the steel is directly poured back to the furnace for discharging after the blowing is finished.
Further, the final gun pressing time in the step (2) is prolonged, and the final gun pressing time is controlled to be in the range of 46s-56s, so that the FeO content in the slag is reduced.
Further, the smelting of the small slag in the step (3) is carried out according to a calculation formula of the addition amount of the converter lime: 2.14 x silicon content x R x 1000/CaO effective content, calculating lime addition amount in each ton of molten iron, making a slag making material count table for low-iron-consumption smelting in a mode according to slag basicity R=2.5-2.8, and adding lime according to the slag making material count table for low-iron-consumption smelting, thereby reducing slag consumption on the premise of ensuring dephosphorization effect.
Further, when lime is added according to a slag making material proportion table for slag smelting, firstly adding light burned dolomite corresponding to the current silicon content, then adding 60-70% of the corresponding lime adding amount in batches, wherein the lime adding amount in each batch is not more than 1.5t, adding one batch every 30s, adding the slag before blowing for 3min, and adding a small amount of lime in batches in the middle stage according to the actual condition of slag melting;
when the initial heat balance is insufficient due to low temperature of molten iron, low silicon and low carbon, adding low silicon iron and coal blocks to perform heat compensation heat, opening full oxygen to pre-blowing oxygen for 30-50s after the half oxygen period is finished, adding slag, and ensuring the early-stage heating effect and the heat compensation material melting heating effect and ensuring the reasonable early-stage temperature interval;
the slag-reserving angle of the conventional heat is controlled to 15+/-5 ℃, the lower the iron loss is, the higher the shaking protection angle is, and when the estimated end temperature is lower than 1580 ℃, the heat is not subjected to slag-reserving operation.
Further, the step (4) of preventing the lining from sticking scrap steel and iron blocks comprises the following steps:
after the steel is placed, the furnace length commands an assistant to splash slag according to the slag condition, commands slag pouring and observes the slag condition in the furnace;
1500kg of bottom ash is added in a thinner furnace time, the furnace is rocked forward to +130°, the bottom ash is paved on the front wall, and then scrap steel adding operation is carried out;
the temperature of the molten iron is lower than 1320 ℃, the furnace is rocked backwards to about-25 ℃ after the addition of scrap steel is finished, and then the iron charging operation is carried out;
after the open-blowing half-oxygen period is finished, controlling the oxygen pressure to be 0.95-1.0MPa, converting for 3min, adjusting the oxygen pressure to be 0.8-0.85MPa, and controlling the gun position of converting for 3-6 min according to 1300-1400 mm;
the end point carbon gun drawing position is 900mm, and the oxygen pressure is controlled to be 0.95-1.0MPa.
Further, deoxidizing substances are added into the peroxide heat in the step (5) to carry out quenching and tempering treatment on the slag, namely, carburant is added into the furnace from the rear of the furnace in the steel placing later stage of the peroxide heat, the slag is deoxidized, slag adjusting agents are added during slag splashing, thickening treatment is carried out on the slag, the slag splashing protection effect is improved, the scouring resistance and erosion resistance of the slag are improved, and the FeO content in the slag is reduced.
Further, the improved slag pressing material proportion in the step (6) is that part of the desulfurization ash is added into the slag for slag pressing, the mass proportion of the slag pressing material to the desulfurization ash is 3:1, and the slag pressing material is added with water and uniformly stirred to be used for slag pressing operation.
Further, the main component of the desulfurization ash is CaO, and the CaO content in the desulfurization ash is within the range of 55% -65%.
The invention has the following beneficial effects:
1. the invention improves the slag splashing furnace protection effect of the converter, improves the erosion resistance of a furnace lining slag layer, and is beneficial to prolonging the service life of the furnace lining by directly tapping after the completion of non-pouring furnace converting, prolonging the final lance pressing time, reducing slag smelting, making measures for preventing scrap sticking, deoxidizing and tempering the slag of the peroxide heat, improving the slag pressing ratio and the like.
2. And in the final stage of blowing, the temperature of the final stage, the carbon content of molten steel and the phosphorus content of molten steel are judged by a T-C-O bullet-throwing type sublance control system, and an operator controls the blowing stopping time according to the measurement result of the bullet-throwing type sublance, and directly pouring the steel into a furnace after blowing is finished, so that the temperature measurement sampling time is saved, and the temperature drop loss is prevented.
3. By prolonging the final-point gun pressing time, the FeO content in the final-point slag is reduced, the slag splashing furnace protection effect is improved, and the problem that the slag layer is low in melting temperature and not resistant to scouring and erosion in the smelting process is solved.
4. The heat absorption of slag materials is reduced through less slag smelting, the heat consumed by slag melting is reduced, the proportion of the heat generated in the converter smelting process for improving the temperature of molten steel is increased, the primary hit rate of the terminal temperature is improved, the frequency of blowing-up and temperature-raising is reduced, the quality of slag is improved, the slag splashing furnace protection effect is improved, and the consumption of flux is less than or equal to 40kg/t.
5. The main means of quenching and tempering the slag by the peroxide heat is to add deoxidizing substances to react with FeO in the slag, reduce the content of FeO in the slag, achieve the purpose of improving the melting point of the slag, improve the slag splashing furnace protection effect and improve the scouring resistance and erosion resistance of the slag. The reduction of the FeO content in the slag solves the problems that under the condition of terminal peroxidation, slag is foamed in the steel discharging process, slag is easy to be discharged from a large furnace mouth, the slag quantity in the furnace is reduced when slag is splashed, the slag splashing furnace protection effect of a converter is affected, and a slag splashing layer with a certain thickness is not formed easily.
6. By making measures for preventing the sticking of scrap steel, the aims of reducing the link frequency of scrap steel and iron blocks which are adhered by melting the scrap steel in a furnace and reducing the temperature loss in the process are fulfilled.
7. By improving the slag pressing charge proportion, the method is beneficial to thickening slag and promoting slag deoxidation. The improved slag pressing material is used for slag pressing operation, so that the slag pressing effect is improved, the slag amount overflowed from a furnace mouth in the steel discharging process is reduced, the thickness of a slag splashing layer during slag splashing furnace protection is increased, and the slag splashing furnace protection effect is improved.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1:
a method of furnace condition maintenance in a low iron loss mode, comprising the steps of:
(1) And at the end of blowing, judging the temperature of the end point, the carbon content of molten steel and the phosphorus content of molten steel by a T-C-O bullet-throwing type sublance control system, and controlling the time for stopping blowing by an operator according to the measurement result of the bullet-throwing type sublance, wherein after blowing, the steel is directly poured back to the furnace for discharging.
(2) The final gun pressing time is prolonged, so that the FeO content in the slag is reduced.
As shown in table 1 below:
table 1: feO content comparison table before and after improving final pressure gun time
As can be seen from Table 1, the time for pressing the gun before improvement is 21-31s, the FeO content in the slag is 16% -20%, the time for pressing the gun after improvement is prolonged to 46s-56s, and the FeO content in the slag is reduced to 15% -16%.
(3) And (3) according to a calculation formula of the addition amount of the converter lime, setting a slag forming material pair table of the low-slag smelting in a low-iron-loss mode according to slag basicity R=2.5-2.8. The slag making material density table of the low slag smelting is shown in table 2:
table 2: slag-making material counter for small slag smelting
As shown in table 2, the lime addition amount per ton of molten iron under the condition of molten iron with different silicon contents is calculated according to a lime addition amount formula, and then the total addition amount of lime is calculated according to the weight of molten iron, so that a slag forming material pair table for slag reduction smelting is manufactured, and the lime addition amount is controlled in the smelting process.
Taking 110t molten iron smelting as an example, when the silicon content of molten iron is detected to be 0.275% at the beginning of smelting, 500kg of light burned dolomite is firstly added, the adding amount of magnesium balls is controlled to be 750kg, then 2177kg of lime is added in batches, each batch of lime is added to be not more than 1.5t, one batch of lime is added every 30s, each batch of slag is blown for 3min before finishing the addition, the rest 933kg of lime is added in small batches in the middle stage according to the actual condition of slag melting, namely, the adding amount of lime in each ton of molten iron is 28.27kg, and the total adding amount of lime 3110kg is controlled, wherein the slag alkalinity R is controlled to be in the range of 2.5-2.8 in the process. On the premise of guaranteeing dephosphorization effect, slag consumption is reduced, slag heat absorption is reduced by slag-less operation, primary hit rate of terminal temperature is improved, blowing-up and temperature-raising frequency is reduced, slag quality is improved, and slag splashing furnace protection effect is improved.
When the initial heat balance is insufficient due to low temperature of molten iron, low silicon and low carbon, low silicon iron and coal blocks are supplemented to carry out heat compensation heat, after the half oxygen period is finished, full oxygen is opened to be blown for 30 seconds, and slag is added, so that the early-stage heating effect and the heat compensation material melting heating effect are ensured, and the reasonable early-stage temperature interval is ensured.
(4) Making measures for preventing scrap steel and iron blocks from adhering to furnace lining:
after the steel is placed, the furnace length commands an assistant to splash slag according to the slag condition, commands slag pouring and observes the slag condition in the furnace;
1500kg of bottom ash is added in a thinner furnace number of slag, the furnace is rocked forward to +130°, the bottom ash is fully paved on the front wall, and then the scrap steel adding operation is carried out, so that the scrap steel is prevented from directly contacting with the slag, and the purpose of preventing the furnace lining from sticking the scrap steel is achieved.
The temperature of molten iron is lower than 1320 ℃, after the addition of scrap steel is finished, the furnace is rocked backwards to about-25 ℃, and then the iron adding operation is carried out, so that the scrap steel adhered on the front surface of the converter falls off, and the defect that the adhered scrap steel cannot be melted due to insufficient heat is prevented;
after the open blowing half oxygen period is finished, controlling the oxygen pressure at 0.95MPa, converting for 3min, adjusting the oxygen pressure to 0.8MPa, converting for 3min, and controlling the gun position at 1300 mm;
the end point carbon gun drawing position is 900mm, and the oxygen pressure is controlled at 0.95MPa.
(5) Deoxidizing substances are added into the peroxidation heat to carry out quenching and tempering treatment on the slag, so that the FeO content in the slag is reduced. Adding carburant into the furnace from the rear of the furnace in the later stage of steel placing in the peroxidation furnace, deoxidizing the slag, adding slag modifier during slag splashing, thickening the slag, and improving slag splashing furnace protection effect and the scouring and erosion resistance of the slag.
(6) The slag pressing materials are prepared from the following pressed materials: the mass ratio of the desulfurized ash to the desulfurized ash is 3:1, the desulfurized ash is added with water and uniformly stirred to be used for slag pressing operation, the slag pressing effect is improved, the slag amount overflowed from a furnace mouth in the steel placing process is reduced, and the thickness of a slag splashing layer is increased. The main component of the desulfurization ash is CaO, and the CaO content in the desulfurization ash is within the range of 55% -65%.
Example 2:
the embodiment provides a method for maintaining furnace conditions in a low iron loss mode, which is basically the same as that of the embodiment 1, and is different in that in the step (3), when initial heat balance is insufficient due to low temperature of molten iron, low silicon and low carbon, low silicon iron and coal are added for performing heat compensation heat treatment, after a half oxygen period is finished, full oxygen is opened to oxygen blowing for 50 seconds, slag is added, so that the early-stage heating effect and the heat compensation material melting heating effect are ensured, and the reasonable early-stage temperature interval is ensured.
In the step (4), after the open-blowing half-oxygen period is finished, the oxygen pressure is controlled at 1.0MPa, the oxygen pressure is adjusted to 0.85MPa after 3min of blowing, the blowing is carried out for 6 min, and the gun position is controlled according to 1400 mm.
Example 3: the embodiment provides a method for maintaining furnace conditions in a low iron loss mode, which is basically the same as that of the embodiment 1, and is different in that in the step (3), when initial heat balance is insufficient due to low temperature of molten iron, low silicon and low carbon, low silicon iron and coal are added for performing heat compensation heat treatment, after a half oxygen period is finished, full oxygen is opened to oxygen blowing for 40 seconds, slag is added, so that the early-stage heating effect and the heat compensation material melting heating effect are ensured, and the reasonable early-stage temperature interval is ensured.
In the step (4), after half oxygen blowing is carried out, the oxygen pressure is controlled at 0.98MPa, the oxygen pressure is adjusted to 0.82MPa after 3min of blowing, the blowing is carried out for 5 min, and the gun position is controlled according to 1350 mm.
The above examples are merely illustrative of the preferred embodiments of the present invention and are not intended to limit the spirit and scope of the present invention. Various modifications and improvements of the technical scheme of the invention, which are made by those skilled in the art, are included in the protection scope of the invention without departing from the design concept of the invention.
The technology, shape, and construction parts of the present invention, which are not described in detail, are known in the art.
Claims (9)
1. A method for furnace maintenance in a low iron loss mode, comprising the steps of:
(1) Directly tapping after the blowing of the non-pouring furnace is finished;
(2) The gun pressing time at the end point is prolonged;
(3) Preparing a slag-making material proportion table for slag-making smelting in a low iron loss mode according to a converter lime addition amount calculation formula, and carrying out slag-making smelting;
(4) Making measures for preventing steel scrap sticking;
(5) Adding deoxidizing substances into the peroxidation heat to carry out quenching and tempering treatment on the slag;
(6) Improving the slag pressing material proportion.
2. The method for maintaining furnace conditions in the low iron loss mode according to claim 1, wherein the step (1) is characterized in that after the completion of the blowing of the non-pouring furnace, the steel is directly tapped, a T-C-O bullet type sublance control system is adopted at the end of the blowing to judge the temperature of the end point, the carbon content of molten steel and the phosphorus content of molten steel, an operator controls the time for stopping the blowing according to the measurement result of the bullet type sublance, and the steel is directly poured back after the blowing is completed.
3. The method for maintaining furnace conditions in low iron loss mode according to claim 1, wherein the extended end lance time in step (2) is controlled to be in the range of 46s to 56s, thereby reducing the FeO content in the slag.
4. The method for maintaining furnace conditions in low iron loss mode according to claim 1, wherein the low slag smelting in step (3) is performed according to the calculation formula of the addition amount of the lime in the converter: 2.14 x silicon content x R x 1000/CaO effective content, calculating lime addition amount in each ton of molten iron, making a slag making material count table for low-iron-consumption smelting in a mode according to slag basicity R=2.5-2.8, and adding lime according to the slag making material count table for low-iron-consumption smelting, thereby reducing slag consumption on the premise of ensuring dephosphorization effect.
5. The method for maintaining furnace conditions in the low iron loss mode according to claim 4, wherein when lime is added according to a slag making table of slag smelting with less slag, firstly adding corresponding light burned dolomite with current silicon content, and then adding 60-70% of the corresponding lime addition amount in batches, wherein the lime addition amount in each batch is not more than 1.5t, one batch is added every 30s, the addition is completed before each batch of slag is blown for 3min, and a small amount of lime is added in the middle stage according to the actual condition of slag melting;
when the initial heat balance is insufficient due to low temperature of molten iron, low silicon and low carbon, adding low silicon iron and coal blocks to perform heat compensation heat, opening full oxygen to pre-blowing oxygen for 30-50s after the half oxygen period is finished, adding slag, and ensuring the early-stage heating effect and the heat compensation material melting heating effect and ensuring the reasonable early-stage temperature interval;
the slag-reserving angle of the conventional heat is controlled to 15+/-5 ℃, the lower the iron loss is, the higher the shaking protection angle is, and when the estimated end temperature is lower than 1580 ℃, the heat is not subjected to slag-reserving operation.
6. The method for maintaining furnace conditions in low iron loss mode according to claim 1, wherein the step (4) of preventing lining scrap and iron blocks comprises the steps of:
after the steel is placed, the furnace length commands an assistant to splash slag according to the slag condition, commands slag pouring and observes the slag condition in the furnace;
1500kg of bottom ash is added in a thinner furnace time, the furnace is rocked forward to +130°, the bottom ash is paved on the front wall, and then scrap steel adding operation is carried out;
the temperature of the molten iron is lower than 1320 ℃, the furnace is rocked backwards to about-25 ℃ after the addition of scrap steel is finished, and then the iron charging operation is carried out;
after the open-blowing half-oxygen period is finished, controlling the oxygen pressure to be 0.95-1.0MPa, converting for 3min, adjusting the oxygen pressure to be 0.8-0.85MPa, and controlling the gun position of converting for 3-6 min according to 1300-1400 mm;
the end point carbon gun drawing position is 900mm, and the oxygen pressure is controlled to be 0.95-1.0MPa.
7. The method for maintaining furnace conditions in the low iron loss mode according to claim 1, wherein the deoxidizing substances are added into the peroxide heat in the step (5) to carry out quenching and tempering treatment on the furnace slag, a carburant is added into the furnace from the rear of the furnace in the later stage of steel discharging of the peroxide heat, the deoxidizing treatment is carried out on the furnace slag, a slag regulator is added during slag splashing, the thickening treatment is carried out on the furnace slag, the slag splashing furnace protection effect is improved, the scouring resistance and erosion resistance of the furnace slag are improved, and the FeO content in the slag is reduced.
8. The method for maintaining furnace conditions in the low iron loss mode according to claim 1, wherein the improved slag pressing material ratio in the step (6) is that part of the desulfurization ash is added into the slag for slag pressing, the mass ratio of the slag pressing material to the desulfurization ash is 3:1, and the slag pressing material and the desulfurization ash are uniformly stirred by adding water and then are used for slag pressing operation.
9. The method for maintaining furnace conditions in a low iron loss mode according to claim 9, wherein the main component of the desulfurization ash is CaO, and the CaO content in the desulfurization ash is in the range of 55% -65%.
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