CN116516101A - Bidirectional circulating furnace lining protection method for converter low-slag smelting - Google Patents
Bidirectional circulating furnace lining protection method for converter low-slag smelting Download PDFInfo
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- CN116516101A CN116516101A CN202310235698.4A CN202310235698A CN116516101A CN 116516101 A CN116516101 A CN 116516101A CN 202310235698 A CN202310235698 A CN 202310235698A CN 116516101 A CN116516101 A CN 116516101A
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- 239000002893 slag Substances 0.000 title claims abstract description 189
- 238000003723 Smelting Methods 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 58
- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 17
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 80
- 239000010959 steel Substances 0.000 claims abstract description 80
- 230000008569 process Effects 0.000 claims abstract description 34
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 18
- 230000008439 repair process Effects 0.000 claims abstract description 17
- 238000007667 floating Methods 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 7
- 239000002184 metal Substances 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 50
- 238000010079 rubber tapping Methods 0.000 claims description 45
- 230000003628 erosive effect Effects 0.000 claims description 32
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 26
- 238000005245 sintering Methods 0.000 claims description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 22
- 229910052760 oxygen Inorganic materials 0.000 claims description 22
- 239000001301 oxygen Substances 0.000 claims description 22
- 239000010410 layer Substances 0.000 claims description 20
- 238000007664 blowing Methods 0.000 claims description 19
- 229910000514 dolomite Inorganic materials 0.000 claims description 13
- 239000010459 dolomite Substances 0.000 claims description 13
- 229910052742 iron Inorganic materials 0.000 claims description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 11
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 11
- 239000004571 lime Substances 0.000 claims description 11
- 230000000630 rising effect Effects 0.000 claims description 11
- 238000012423 maintenance Methods 0.000 claims description 10
- 239000011819 refractory material Substances 0.000 claims description 9
- 239000002131 composite material Substances 0.000 claims description 7
- 239000011241 protective layer Substances 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 239000003607 modifier Substances 0.000 claims description 6
- RWDBMHZWXLUGIB-UHFFFAOYSA-N [C].[Mg] Chemical compound [C].[Mg] RWDBMHZWXLUGIB-UHFFFAOYSA-N 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 235000001674 Agaricus brunnescens Nutrition 0.000 claims description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 4
- 239000010931 gold Substances 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 239000011777 magnesium Substances 0.000 claims description 4
- 238000009628 steelmaking Methods 0.000 claims description 4
- 238000009529 body temperature measurement Methods 0.000 claims description 3
- 238000012790 confirmation Methods 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 239000002905 metal composite material Substances 0.000 claims description 3
- 239000011148 porous material Substances 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 239000007921 spray Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 229910000805 Pig iron Inorganic materials 0.000 claims description 2
- 239000002436 steel type Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 230000002035 prolonged effect Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000000149 penetrating effect Effects 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000009991 scouring Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 241000143432 Daldinia concentrica Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000005502 peroxidation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/44—Refractory linings
- C21C5/441—Equipment used for making or repairing linings
- C21C5/443—Hot fettling; Flame gunning
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/44—Refractory linings
- C21C5/445—Lining or repairing the taphole
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/46—Details or accessories
- C21C5/4653—Tapholes; Opening or plugging thereof
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/46—Details or accessories
- C21C5/48—Bottoms or tuyéres of converters
-
- 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 metal smelting, and particularly relates to a method for protecting a bidirectional circulating furnace lining for converter low-slag smelting. The method comprises the following steps: (1) controlling slag indexes in smelting: mgO content and slag alkalinity control measures, feO content control measures and end slag viscosity control measures are adopted in the smelting process; (2) increasing the carbon drawing level and reducing the number of blowups; (3) Repairing furnace linings at the positions of the furnace bottom and trunnions at two sides, and repairing the furnace linings with heavy damage by increasing the floating amount of slag; and (4) taking different repair measures according to different temperatures. The invention plays a role in thoroughly repairing and protecting the converter lining by strictly controlling the technical index of slag and effective repairing measures in the smelting process, prolongs the service life of the lining, reduces the smelting cost and improves the quality of molten steel.
Description
Technical Field
The invention belongs to the technical field of metal smelting, and particularly relates to a method for protecting a bidirectional circulating furnace lining for converter low-slag smelting.
Background
The service life of the converter lining is a key economic and technical index for measuring the working procedures of an enterprise converter. In the metal smelting process, the furnace lining material is in a severe environment of high temperature, mechanical impact and chemical erosion for a long time, especially under the condition of poor molten iron conditions and strict steel grade process requirements, the smelting difficulty is increased, the material-slag-gold protective layer on the surface of the furnace lining is deteriorated, and the erosion of each part of the furnace lining is aggravated. The traditional slag splashing furnace protection technology can maintain the furnace lining of the converter in two modes of slag splashing lining making and repairing material repairing, but the furnace lining cannot be thoroughly maintained fundamentally, and the current furnace lining repairing mode has the following problems:
(1) Slag basicity is high: the consumption of lime is large, so that high-alkalinity furnace slag is formed, a large amount of lime is needed to be added for manufacturing the high-alkalinity furnace slag, the slag amount in the process is large, a large amount of iron and steel materials and temperature loss are taken away, and the reduction of steelmaking cost is not facilitated;
(2) The repairing material is not sintered firmly: the refractory material for repairing is added in the process of repairing furnace, which has poor sintering firmness, low overall strength, poor anti-scouring capability, high erosion speed and low service life, thus frequent repairing furnace is caused and a large amount of production time is occupied;
(3) The erosion principle is not clear, resulting in blind repair: the erosion mechanism of the furnace lining is unclear, the process technology is lacked, and important maintenance is not carried out on the part with high erosion speed of the furnace lining, so that the local erosion of the furnace lining is too fast, and the serious process accident of penetrating the molten steel into the furnace shell is caused;
(4) Fast erosion, high cost, large risk: the rapid erosion of the furnace lining by the blast furnace slag, the massive consumption of refractory materials and the steel penetrating process accident of the furnace shell increase the smelting cost and reduce the yield of molten steel and the safety risk.
(5) The difference in the positions of the lining materials causes erosion of the lining: due to the difference of the working environments of furnace lining materials at all parts, different erosion phenomena occur, the traditional slag splashing furnace protection technology repairs the furnace lining in a high-temperature self-flowing way by slag splashing or repairing materials, a uniform slag hanging protection layer is difficult to form on the surface of the furnace lining, and the local parts with serious erosion damage cannot be thoroughly repaired, so that the service life of the furnace lining is shortened, and the repair cost of a converter is increased;
(6) The high-temperature molten steel causes corrosion of a furnace lining: the on-site process conditions need different tapping temperatures, the yield strength of the refractory material of the tap hole can be reduced by molten steel with the temperature of more than 1670 ℃, the yield strength of the refractory material can be obviously reduced along with the temperature rise, the erosion speed of the tap hole is increased, and the service life of the tap hole is shortened;
(7) Excess FeO causes erosion of the lining: in the smelting process, the phenomenon of excessive oxygen supply is caused by operation reasons, a large amount of FeO appears in molten steel, the FeO is fused with steel slag, the oxidability of the steel slag is increased, redundant oxygen molecules in the molten steel and the steel slag abstract carbon elements in magnesium-carbon materials of a steel tapping hole during steel tapping, chemical reaction is generated, the structure of refractory materials at the position of the steel tapping hole is loosened, and the yield strength of the refractory materials of the steel tapping hole is reduced;
(8) Slag basicity and MgO cause erosion of the lining: in the smelting process, as the smelting process is needed, in order to continuously reduce the slag quantity of the converter, the slag alkalinity is required to be continuously reduced, when the slag alkalinity is lower than 2.6 and the MgO content is lower than 8%, part of slag and a steel tapping hole are subjected to chemical reaction in the steel tapping process, so that the chemical erosion speed of the steel tapping hole is increased;
(9) The steel tapping hole installation angle deviation causes erosion of furnace lining: when the center deviation of the steel outlet after replacement is larger than 1 DEG, molten steel passes through the steel outlet according to an inclined angle, so that the lateral pressure and scouring force of the molten steel to the steel outlet are increased, the abrasion speed of the steel outlet is increased, the service life of the steel outlet is shortened, in addition, the deviation of the angle of the steel outlet is caused, molten steel is inclined into a ladle in the process of shaking a furnace, the phenomenon of swirling slag of the molten steel is caused, the erosion speed of the steel outlet is increased when the molten steel mixed with slag passes through the steel outlet, and the service life of the steel outlet is shortened;
(10) Other causes cause erosion of the lining: because of the instability of control parameters such as gun position, oxygen pressure, oxygen flow and the like of the converter, the impact part of the furnace lining is easy to be scoured and eroded prematurely, and for the part with serious erosion, repair measures are needed to be adopted for each furnace, and the repair quantity and repair time of each time are correspondingly increased along with the continuous increase of the furnace age until the furnace is no longer repaired, the use of the furnace lining is stopped, and the converter overhaul stage is entered.
Disclosure of Invention
The invention aims to provide a bidirectional circulating furnace lining protection method for converter low-slag smelting, which aims to solve the problems in the prior art.
The technical scheme adopted for solving the technical problems is as follows: a converter low slag smelting bidirectional circulation furnace lining protection method comprises the following steps:
(1) Slag indexes are controlled in smelting: mgO content and slag alkalinity control measures, feO content control measures and end slag viscosity control measures are adopted in the smelting process;
(2) The carbon pulling level is improved and the blowing times are reduced;
(3) Repairing furnace linings at the positions of the furnace bottom and trunnions at two sides, and repairing the furnace linings with heavy damage by increasing the floating amount of slag;
(4) Different repair measures are adopted according to different temperatures: when the temperature of the furnace body is less than or equal to 320 ℃, adjusting the slag component to ensure that the slag is uniformly hung on the inner wall of the furnace lining for repairing; when the temperature of the furnace body is more than or equal to 350 ℃, adopting slag reserving, repairing material, iron block repairing, hot repairing front large surface, hot repairing rear large surface and furnace bottom shaking furnace feeding, and replacing a tapping hole for repairing.
Further, the MgO content and slag alkalinity control measures in the step (1) are as follows: the MgO content in the slag is controlled to be 6-8% by slag adjustment and gun pressing measures, the alkalinity of the slag is 2.3+/-0.1, and lime and dolomite are added according to the components and the alkalinity of the final slag, so that the bottom blowing flow is ensured to be not lower than 900m 3 And under the condition of/h, eliminating the phenomenon of overhigh slag at the bottom, if the phenomenon of dry back occurs, lifting a gun in time to melt slag, adding a slag adjusting modifier according to the temperature condition of molten steel to assist in melting slag, and applying the slag to the bottom of a furnace to quickly form a slag-metal mushroom head so as to prevent a bottom blowing air supply element from being blocked.
Further, feO content control measures in the step (1) are as follows: the lance position is reasonably controlled in the smelting process, the oxygen lance pressure is controlled to be 0.85-0.95MPa, and the flow is controlled to be 36500-38000Nm 3 And/h, controlling the FeO content in the molten steel to be within 13%, and reducing the erosion rate of liquid slag to a furnace lining.
Further, the end slag viscosity control measure in the step (1) is as follows: confirming and adjusting the concentration of the residual slag in the furnace after tapping, wherein in the smelting process, slag-forming materials including but not limited to steelmaking lime, light burned dolomite, carbon-containing materials and slag-adjusting modifiers are added into the furnace, the viscosity of the end slag is controlled to be 0.4-0.6 Pa.S, and 200-300kg of magnesium carbon spheres, magnesium spheres and dolomite are needed to be added into the thinner slag after tapping to splash the slag; the rising speed of the bottom of the furnace is controlled, the slight rising principle is controlled, the rising amplitude of the bottom of the furnace is controlled to be +/-150 mm, the thickness of the slag layer is controlled to be 50-150mm, the bottom blowing air supply element is ensured to be visible for each furnace, and the thickness of the slag layer of the bottom of the furnace is measured and confirmed for each shift.
Further, in the step (2), the carbon drawing level is increased and the number of the supplementary blowing times is reduced as follows: the smelting process of molten steel is stabilized, the large-scale adjustment of the oxygen content and gun position in the middle and later stages is reduced, the smelting temperature and final slag alkalinity of the molten steel are reasonably controlled, the primary hit rate of smelting is improved, the secondary supplementary blowing is reduced, the oxygen enrichment phenomenon in the molten steel is avoided, and the iron oxide content of steel types and the lining erosion phenomenon caused by high-temperature molten steel are reduced; when the carbon pulling temperature is high, lime or dolomite is added for cooling; when the carbon pulling temperature is low, the temperature is raised at the speed of 1-2 ℃ per second, and the floating slag is thoroughly melted; when unmelted lump slag is generated, the slag melting and cooling phenomenon is avoided by reasonably controlling according to the terminal carbon condition, and the low-temperature steel phenomenon is avoided by performing temperature measurement confirmation before tapping after smelting is finished.
Further, the measures for increasing the floating amount of the slag in the step (3) are as follows: the bulk feeding material is put in the burning position of local damage, the height position of an oxygen gun is adjusted, high-pressure nitrogen is opened after 1800mm away from the furnace bottom, the pressure of the nitrogen is adjusted to 1.1MPa, and the flow is controlled to 40000Nm 3 And (h) spraying high-speed nitrogen jet flow sprayed by the oxygen gun to uniformly spray high-melting-point slag in a furnace bottom molten pool onto the surfaces of furnace linings at the trunnion and the furnace bottom positions at the two sides, increasing the adhesion and floatation quantity of slag at the trunnion and the furnace bottom positions at the two sides, and effectively protecting the furnace linings at the trunnion and the furnace bottom positions.
Further, slag remaining, repairing mass and iron block repairing measures in the step (4) are as follows: 1 time of pig iron block repairing furnace per shift, controlling standard 0.5t repairing furnace block, slag reserving and iron block modes, controlling total thickness to be less than or equal to 50mm, facilitating forming of a slag-metal composite protective layer, and controlling sintering time according to 10-15 min; when the sintering material is 0.5-1.0t, the sintering time is controlled to be within 20-30min, and the sintering of the furnace material is firm; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
Further, the major measures before hot patching in the step (4) are as follows: the method comprises the steps of adopting a furnace lining repairing measure of adding a repairing mass of 0.5t and a certain amount of iron blocks into slag left in each shift, controlling the total repairing thickness to be within 50mm, enabling the slag left in each shift to quickly form a material-slag-gold composite protective layer, controlling sintering time to be within 20-30min when the sintering material is 0.5-1.0t, and firmly sintering the furnace burden.
Further, the feeding measures of the rear large surface and the furnace bottom shaking furnace in the step (4) are as follows: repairing by using a repairing mode of slag remaining in the furnace and adding repairing materials, continuously adding the repairing materials at the position of the rear large surface, forming a repairing furnace layer at the erosion part, and repairing the rear large surface by adopting a front-rear shaking furnace repairing mode after the middle part and the two sides of the rear large surface; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
Further, in the step (4), the measure of replacing the tap hole is as follows: the method comprises the steps of replacing a steel-tapping hole, boring an inner hole of the steel-tapping hole by using a furnace disassembly machine, wherein the inner circle of a machined pore canal is required to be smooth and perpendicular to a central line of a furnace body, the perpendicularity deviation of the central line of the inner hole is controlled to be within 1 ℃, after the steel-tapping hole is replaced, a certain amount of refractory material is manually thrown on the surface of the steel-tapping hole in the furnace to form a composite material layer structure, the furnace body is splashed after being erected, after the splashing is finished, the furnace body is rotated backwards to hang slag on the rear surface, and when a small amount of slag passes through the steel-tapping hole, part of steel slag is attached to the periphery of the steel-tapping hole to form a protective slag layer, so that damaged parts of the steel slag layer are thoroughly repaired.
The invention has the following beneficial effects: compared with the prior lining repair technology, the bidirectional circulating lining protection method for converter low-slag smelting changes the traditional furnace protection technology for maintaining the lining by using the spray repairing material and the hot self-flow slag splashing repair mode, obtains reasonable final slag viscosity, alkalinity, feO and MgO technical indexes through strict control on the smelting operation process, and changes the repairing effect of the converter lining by adding effective splashing measures on each part of the lining, plays a role in thoroughly repairing the converter lining, and plays a key role in realizing long service life of the lining, low smelting cost and high quality of molten steel:
(1) According to the technical scheme, the double effects of high-efficiency maintenance and slag-less smelting of the converter lining can be achieved, reasonable time control is adopted according to the erosion condition of the repairing position, and the phenomenon of unstable sintering after repairing a large amount of furnace burden is changed.
(2) In the furnace repairing process, the addition of furnace burden is less, the environmental temperature in the furnace is high, the repairing of the corroded part is tight, the repairing is solid, the furnace burden is firmly sintered, the service time of the furnace lining is long, the repairing effect is good, and the furnace repairing cost is low.
(3) The reasonable control of the smelting operation process eliminates the peroxidation phenomenon of molten steel, reduces the FeO content of slag, changes the erosion environment of a furnace lining and improves the quality of molten steel.
(4) The reasonable control of the alkalinity in the smelting process is beneficial to the slag to be fully distributed on the bottom of the furnace, and a slag-metal mushroom head protecting bottom blowing air supply element is formed rapidly.
(5) The reasonable control of the low MgO content in the slag can avoid the phenomenon of high viscosity of the slag caused by the re-blowing process, avoid the problems of rising of the bottom of the furnace after steel is put, blocking of bottom ventilation elements and the like, and ensure the blowing effect of the bottom of the converter.
(6) Creates conditions for refining desulfurization, reduces the desulfurization burden of the refining furnace, and plays a key role in reducing the operation time and the production cost of the refining furnace.
(7) The repair measures of the furnace lining of the trunnion, the furnace bottom, the front surface, the rear surface and the steel tapping hole on the two sides of the furnace body are respectively and effectively maintained according to the temperature of the furnace shell, so that the service life of the converter is prolonged, and a large amount of refractory repair materials are saved.
(8) Through reasonable control of the temperature of molten steel, the oxygen content and the installation angle of the steel tapping hole, the erosion condition of the steel tapping hole caused by the temperature of molten steel, steel slag and the angle of the steel tapping hole can be reduced, and the service life of the steel tapping hole is prolonged.
(9) High efficiency of furnace lining maintenance is realized, production time occupied by a conventional furnace repairing method is saved, and molten steel yield and working efficiency are improved.
(10) The reasonable addition amount and the sintering strength of the furnace protection material are obviously improved, so that the later furnace repair material is reduced, the cost investment of the furnace protection material is reduced, the steel penetrating accident of the converter is reduced, and the safety performance of converter smelting is improved.
(11) The service life of the furnace lining is prolonged from the conventional 15000 furnace to about 40000 furnace, the service life is prolonged by 2.5 times, and the service life of the converter is greatly prolonged.
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: the smelting slag making system and the furnace body maintenance system are enhanced, which is an important measure for prolonging the service life of the furnace lining; for the furnace lining damaged in advance in the smelting process, different repair and prevention measures can be adopted according to the damaged part and the damage degree of the furnace lining. After converting, high-speed nitrogen jet of top-blown oxygen gun is used to impact the high-melting slag in molten pool to the corrosion part, so that the slag is sprayed and adhered to the surface of furnace lining uniformly to form slag protecting layer, thus reaching the aim of protecting furnace lining.
(1) In the smelting, the viscosity control measure of the end slag is adopted, so that the slag hanging effect of the slag is improved: in the smelting process, adding slag-making materials such as steelmaking lime, light burned dolomite, carbonaceous materials or slag-adjusting modifier and the like into the furnace, controlling the viscosity of the end slag to 0.4-0.6 Pa.S, confirming the condition of the slag after tapping, and adding 200-300kg of dolomite or magnesium carbon spheres or magnesium spheres into the furnace when the slag is thinner, so as to splash the slag to dry and increase the viscosity of the slag; when the slag is in a dry return phenomenon, the gun is required to be lifted in time to dissolve the slag, a proper amount of slag adjusting modifier is added according to the temperature of molten steel to assist dissolving the slag, and magnesium carbon balls or magnesium balls or dolomite are added to splash the slag to dry, so that the viscosity of the slag is increased, and the thickness of a slag layer is controlled to be 50-150 mm. The height position of the oxygen lance is adjusted, high-pressure nitrogen is opened after the distance from the furnace bottom is 1800mm, the pressure of the nitrogen is adjusted to 1.1MPa, and the flow is controlled to 40000Nm 3 And/h, uniformly spraying the bottom slag on the surfaces of the furnace lining at the trunnion and furnace bottom positions at two sides by using high-speed nitrogen jet flow, and increasing the adhesion and floatation quantity of the furnace lining to the steel slag.
(2) MgO content and slag alkalinity control measures are adopted in smelting, so that the bottom blowing ventilation effect is improved:
slag adjustment and gun pressing measures should be timely adopted during smelting, so that slag is always in good fluidity, and the alkalinity range of the slag is controlled to be: 2.3+/-0.1, controlling MgO in the slag to be 6-8%, adding proper amount of lime and dolomite according to the components and alkalinity of the final slag, lifting a gun in time to dissolve slag if a re-drying phenomenon occurs in the smelting process, adding proper amount of slag according to the temperature condition of molten steel to assist dissolving slag, so that the slag is coated on the bottom of a furnace, and a slag-metal mushroom head is formed rapidly to protect a bottom blowing air supply element from being blocked
(3) FeO content control measures are adopted in smelting: reasonably controlling oxygen supply pressure of 0.85-0.95MPa and flow rate of 36500-38000Nm in smelting process 3 And/h, the problem of exceeding FeO content caused by the oxygen enrichment phenomenon of molten steel is avoided, the FeO content in slag is controlled to be within 13%, and the erosion rate of liquid slag to a furnace lining is reduced.
(4) Controlling the furnace bottom to rise: the rising speed of the furnace bottom is controlled, the principle of slight rising is controlled, the rising amplitude of the furnace bottom is controlled to be +/-150 mm, the bottom blowing nozzle element can be ensured to be clearly visible in the rising process of the furnace bottom, and the thickness of the furnace bottom is measured every shift.
(5) Different repair measures are adopted according to different temperatures: when the temperature is less than or equal to 320 ℃, the slag component hanging furnace wall is adjusted in time; when the temperature is more than or equal to 350 ℃, the on-duty scheduling is timely linked to take slag reserving, repairing mass and iron block repairing measures, and the repairing mass is used for 1 time for each shift, the standard 0.5t repairing mass, slag reserving and iron block mode is controlled, the total thickness is controlled to be less than or equal to 50mm, and the forming of a slag-metal composite protective layer is facilitated; when the sintering material is 0.5-1.0t, the sintering time is controlled to be within 20-30min, and the sintering of the furnace material is firm; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
(6) The carbon pulling level is improved, and the supplementary blowing times are reduced: the smelting process of molten steel is stabilized, the large-scale adjustment of the oxygen content and gun position in the middle and later stages is reduced, the smelting temperature and final slag alkalinity of the molten steel are reasonably controlled, the primary hit rate of smelting is improved, the secondary supplementary blowing is reduced, the oxygen enrichment phenomenon in the molten steel is avoided, and the lining erosion phenomenon caused by the FeO content of steel and high-temperature molten steel is reduced; when the carbon pulling temperature is high, a proper amount of lime or dolomite is added for cooling; when the carbon pulling temperature is low, the temperature is raised at the speed of 1-2 ℃ per second, and the floating slag is thoroughly melted; when unmelted lump slag is generated, reasonable control is carried out according to the condition of end point carbon, so that the phenomenon of slag melting and cooling is avoided, the work of temperature measurement and confirmation before tapping is carried out after smelting is finished, and the phenomenon of low-temperature steel is avoided.
(7) And (3) feeding measures of the rear large-surface and furnace bottom shaking furnace: when the temperature of the furnace body is less than or equal to 320 ℃, timely repairing the facets by timely adjusting slag components; the temperature of the furnace body is more than or equal to 350 ℃, the repairing is carried out by adopting a repairing mode of slag remaining in the furnace and adding repairing materials, the repairing materials are continuously put into the position of the rear large surface, a repairing furnace layer is formed at the erosion part, and the middle part and the two sides of the rear large surface are repaired by adopting a front-back furnace rocking repairing mode; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
(8) The following steps are adopted before hot patching: when the temperature of the furnace body is less than or equal to 320 ℃, the slag component is timely adjusted to lead the slag to be uniformly hung on the inner wall of the furnace lining; when the temperature of the furnace body is more than or equal to 350 ℃, slag is reserved, a repairing material of 0.5t and a furnace lining repairing measure of a certain amount of iron blocks are adopted in each shift, the total repairing thickness is controlled within 50mm, a material-slag-gold composite protective layer is formed rapidly, the sintering time is controlled according to 10-15min, the sintering time is controlled within 20-30min when the sintering material is 0.5-1.0t, and the furnace material is sintered firmly.
(9) Repair of the trunnion positions on both sides: the furnace lining with heavier damage is required to be put in a locally damaged burning position to form a composite layer structure, the height position of an oxygen lance is adjusted, high-pressure nitrogen is opened after the distance from the furnace bottom is 1800mm, the pressure of the nitrogen is adjusted to 1.1MPa, and the flow is controlled to 40000Nm 3 And/h, the bottom slag is uniformly sprayed on the surface of the furnace lining at the trunnion positions at two sides by utilizing high-speed nitrogen jet flow, so that the adhesion and floatation quantity of the furnace lining to the steel slag are increased, and the service life of the furnace lining is prolonged.
(10) Repairing the tapping hole: when the surface temperature of the furnace body is less than or equal to 320 ℃, the slag component is timely adjusted to uniformly hang the slag on the surface of the peripheral furnace lining of the steel tapping hole, so that the purpose of automatically repairing the steel tapping hole is achieved; when the temperature is more than or equal to 350 ℃, the tapping hole is required to be replaced, a furnace disassembly machine is used for boring an inner hole of the tapping hole, the inner circle of a machined pore canal is required to be smooth and vertical to a furnace body center line, the perpendicularity deviation of the inner hole center line is controlled to be within 1 ℃, after the tapping hole is replaced, a certain amount of refractory material is manually thrown on the surface of the tapping hole in the furnace to form a composite material layer structure, the furnace body is lifted up to splash slag, after the splash slag is finished, the furnace body is rotated backwards to hang slag on the rear surface, and when a small amount of slag passes through the tapping hole, part of slag is attached to the periphery of the tapping hole to form a protective slag layer, and the damaged part of the slag layer is thoroughly repaired.
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 (10)
1. The method for protecting the converter low-slag smelting bidirectional circulating furnace lining is characterized by comprising the following steps of:
(1) Slag indexes are controlled in smelting: mgO content and slag alkalinity control measures, feO content control measures and end slag viscosity control measures are adopted in the smelting process;
(2) The carbon pulling level is improved and the blowing times are reduced;
(3) Repairing furnace linings at the positions of the furnace bottom and trunnions at two sides, and repairing the furnace linings with heavy damage by increasing the floating amount of slag;
(4) Different repair measures are adopted according to different temperatures: when the temperature of the furnace body is less than or equal to 320 ℃, adjusting the slag component to ensure that the slag is uniformly hung on the inner wall of the furnace lining for repairing; when the temperature of the furnace body is more than or equal to 350 ℃, adopting slag reserving, repairing material, iron block repairing, hot repairing front large surface, hot repairing rear large surface and furnace bottom shaking furnace feeding, and replacing a tapping hole for repairing.
2. The method for protecting the bidirectional circulating furnace lining for converter low-slag smelting according to claim 1, wherein the MgO content and slag alkalinity control measures in the step (1) are as follows:the MgO content in the slag is controlled to be 6-8% by slag adjustment and gun pressing measures, the alkalinity of the slag is 2.3+/-0.1, and lime and dolomite are added according to the components and the alkalinity of the final slag, so that the bottom blowing flow is ensured to be not lower than 900m 3 And under the condition of/h, eliminating the phenomenon of overhigh slag at the bottom, if the phenomenon of dry back occurs, lifting a gun in time to melt slag, adding a slag adjusting modifier according to the temperature condition of molten steel to assist in melting slag, and applying the slag to the bottom of a furnace to quickly form a slag-metal mushroom head so as to prevent a bottom blowing air supply element from being blocked.
3. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein FeO content control measures in the step (1) are as follows: the lance position is reasonably controlled in the smelting process, the oxygen lance pressure is controlled to be 0.85-0.95MPa, and the flow is controlled to be 36500-38000Nm 3 And/h, controlling the FeO content in the molten steel to be within 13%, and reducing the erosion rate of liquid slag to a furnace lining.
4. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein the end slag viscosity control measure in the step (1) is as follows: confirming and adjusting the concentration of the residual slag in the furnace after tapping, wherein in the smelting process, slag-forming materials including but not limited to steelmaking lime, light burned dolomite, carbon-containing materials and slag-adjusting modifiers are added into the furnace, the viscosity of the end slag is controlled to be 0.4-0.6 Pa.S, and 200-300kg of magnesium carbon spheres, magnesium spheres and dolomite are needed to be added into the thinner slag after tapping to splash the slag; the rising speed of the bottom of the furnace is controlled, the slight rising principle is controlled, the rising amplitude of the bottom of the furnace is controlled to be +/-150 mm, the thickness of the slag layer is controlled to be 50-150mm, the bottom blowing air supply element is ensured to be visible for each furnace, and the thickness of the slag layer of the bottom of the furnace is measured and confirmed for each shift.
5. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein the step (2) of increasing the carbon pulling level and reducing the number of times of reblowing is as follows: the smelting process of molten steel is stabilized, the large-scale adjustment of the oxygen content and gun position in the middle and later stages is reduced, the smelting temperature and final slag alkalinity of the molten steel are reasonably controlled, the primary hit rate of smelting is improved, the secondary supplementary blowing is reduced, the oxygen enrichment phenomenon in the molten steel is avoided, and the iron oxide content of steel types and the lining erosion phenomenon caused by high-temperature molten steel are reduced; when the carbon pulling temperature is high, lime or dolomite is added for cooling; when the carbon pulling temperature is low, the temperature is raised at the speed of 1-2 ℃ per second, and the floating slag is thoroughly melted; when unmelted lump slag is generated, the slag melting and cooling phenomenon is avoided by reasonably controlling according to the terminal carbon condition, and the low-temperature steel phenomenon is avoided by performing temperature measurement confirmation before tapping after smelting is finished.
6. The method for protecting the bidirectional circulating furnace lining for converter low-slag smelting according to claim 1, wherein the step (3) is characterized in that the measures for increasing the sticking and floating amount of slag are as follows: the bulk feeding material is put in the burning position of local damage, the height position of an oxygen gun is adjusted, high-pressure nitrogen is opened after 1800mm away from the furnace bottom, the pressure of the nitrogen is adjusted to 1.1MPa, and the flow is controlled to 40000Nm 3 And (h) spraying high-speed nitrogen jet flow sprayed by the oxygen gun to uniformly spray high-melting-point slag in a furnace bottom molten pool onto the surfaces of furnace linings at the trunnion and the furnace bottom positions at the two sides, increasing the adhesion and floatation quantity of slag at the trunnion and the furnace bottom positions at the two sides, and effectively protecting the furnace linings at the trunnion and the furnace bottom positions.
7. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein slag remaining, repairing mass and iron block repairing measures in the step (4) are as follows: 1 time of pig iron block repairing furnace per shift, controlling standard 0.5t repairing furnace block, slag reserving and iron block modes, controlling total thickness to be less than or equal to 50mm, facilitating forming of a slag-metal composite protective layer, and controlling sintering time according to 10-15 min; when the sintering material is 0.5-1.0t, the sintering time is controlled to be within 20-30min, and the sintering of the furnace material is firm; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
8. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein the hot patching in the step (4) comprises the following steps: the method comprises the steps of adopting a furnace lining repairing measure of adding a repairing mass of 0.5t and a certain amount of iron blocks into slag left in each shift, controlling the total repairing thickness to be within 50mm, enabling the slag left in each shift to quickly form a material-slag-gold composite protective layer, controlling sintering time to be within 20-30min when the sintering material is 0.5-1.0t, and firmly sintering the furnace burden.
9. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting according to claim 1, wherein the feeding measures of the rear large surface and furnace bottom shaking furnace in the step (4) are as follows: repairing by using a repairing mode of slag remaining in the furnace and adding repairing materials, continuously adding the repairing materials at the position of the rear large surface, forming a repairing furnace layer at the erosion part, and repairing the rear large surface by adopting a front-rear shaking furnace repairing mode after the middle part and the two sides of the rear large surface; when the maintenance and shutdown time exceeds 40min, 1t repairing material is used for repairing the large rear side surface, and the thickness of the repairing material at the bottom of the furnace is controlled to be between-100 mm and +300 mm.
10. The method for protecting the bidirectional circulating furnace lining for converter low slag smelting of claim 1, wherein the step (4) of replacing the tap hole is performed by the following steps: the method comprises the steps of replacing a steel-tapping hole, boring an inner hole of the steel-tapping hole by using a furnace disassembly machine, wherein the inner circle of a machined pore canal is required to be smooth and perpendicular to a central line of a furnace body, the perpendicularity deviation of the central line of the inner hole is controlled to be within 1 ℃, after the steel-tapping hole is replaced, a certain amount of refractory material is manually thrown on the surface of the steel-tapping hole in the furnace to form a composite material layer structure, the furnace body is splashed after being erected, after the splashing is finished, the furnace body is rotated backwards to hang slag on the rear surface, and when a small amount of slag passes through the steel-tapping hole, part of steel slag is attached to the periphery of the steel-tapping hole to form a protective slag layer, so that damaged parts of the steel slag layer are thoroughly repaired.
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