CN117821702A - Low-cost high-efficiency desulfurizing agent for converter direct continuous casting and production process thereof - Google Patents
Low-cost high-efficiency desulfurizing agent for converter direct continuous casting and production process thereof Download PDFInfo
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- CN117821702A CN117821702A CN202311676510.6A CN202311676510A CN117821702A CN 117821702 A CN117821702 A CN 117821702A CN 202311676510 A CN202311676510 A CN 202311676510A CN 117821702 A CN117821702 A CN 117821702A
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- 230000003009 desulfurizing effect Effects 0.000 title claims abstract description 41
- 238000009749 continuous casting Methods 0.000 title claims abstract description 27
- 238000004519 manufacturing process Methods 0.000 title claims description 28
- 239000011593 sulfur Substances 0.000 claims abstract description 85
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 85
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 45
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 38
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 36
- 239000000843 powder Substances 0.000 claims abstract description 36
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims abstract description 33
- 235000011941 Tilia x europaea Nutrition 0.000 claims abstract description 33
- 239000004571 lime Substances 0.000 claims abstract description 33
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims abstract description 32
- 239000010436 fluorite Substances 0.000 claims abstract description 30
- 230000008569 process Effects 0.000 claims abstract description 30
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 27
- 239000010959 steel Substances 0.000 claims abstract description 27
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 24
- 230000023556 desulfurization Effects 0.000 claims abstract description 24
- 239000004576 sand Substances 0.000 claims abstract description 20
- 238000003756 stirring Methods 0.000 claims abstract description 18
- 238000002360 preparation method Methods 0.000 claims abstract description 16
- 239000002994 raw material Substances 0.000 claims abstract description 16
- 238000002161 passivation Methods 0.000 claims abstract description 13
- 238000010079 rubber tapping Methods 0.000 claims abstract description 12
- 238000007664 blowing Methods 0.000 claims abstract description 8
- 238000005516 engineering process Methods 0.000 claims abstract description 7
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims abstract description 7
- 238000012545 processing Methods 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 26
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 25
- 239000002893 slag Substances 0.000 claims description 25
- 238000012360 testing method Methods 0.000 claims description 10
- 239000008187 granular material Substances 0.000 claims description 9
- 238000010298 pulverizing process Methods 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 230000009471 action Effects 0.000 claims description 6
- 230000007547 defect Effects 0.000 claims description 6
- 238000000227 grinding Methods 0.000 claims description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 238000000265 homogenisation Methods 0.000 claims description 5
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 241000219000 Populus Species 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 claims description 4
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 claims description 4
- 239000003830 anthracite Substances 0.000 claims description 4
- 238000000889 atomisation Methods 0.000 claims description 4
- 239000004568 cement Substances 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 239000002131 composite material Substances 0.000 claims description 4
- 239000002283 diesel fuel Substances 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 4
- 239000000428 dust Substances 0.000 claims description 4
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 238000005245 sintering Methods 0.000 claims description 4
- 238000003860 storage Methods 0.000 claims description 4
- 238000005303 weighing Methods 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 241000196324 Embryophyta Species 0.000 claims description 2
- 235000019738 Limestone Nutrition 0.000 claims description 2
- 238000000498 ball milling Methods 0.000 claims description 2
- 238000001354 calcination Methods 0.000 claims description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 2
- 239000003245 coal Substances 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 210000002615 epidermis Anatomy 0.000 claims description 2
- 239000004744 fabric Substances 0.000 claims description 2
- 239000000945 filler Substances 0.000 claims description 2
- 239000006028 limestone Substances 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims description 2
- 238000012856 packing Methods 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims description 2
- 239000002689 soil Substances 0.000 claims description 2
- 238000003892 spreading Methods 0.000 claims description 2
- 230000007480 spreading Effects 0.000 claims description 2
- 239000004575 stone Substances 0.000 claims description 2
- 210000003462 vein Anatomy 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 238000007670 refining Methods 0.000 abstract description 18
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 abstract description 8
- 229910052786 argon Inorganic materials 0.000 abstract description 4
- 238000005266 casting Methods 0.000 abstract description 4
- 229910000616 Ferromanganese Inorganic materials 0.000 abstract description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 abstract description 3
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 abstract description 3
- 239000011707 mineral Substances 0.000 abstract description 3
- 238000004064 recycling Methods 0.000 abstract description 3
- 239000002910 solid waste Substances 0.000 abstract description 3
- OSMSIOKMMFKNIL-UHFFFAOYSA-N calcium;silicon Chemical compound [Ca]=[Si] OSMSIOKMMFKNIL-UHFFFAOYSA-N 0.000 abstract 1
- 240000006909 Tilia x europaea Species 0.000 description 21
- 230000000694 effects Effects 0.000 description 7
- 229910000975 Carbon steel Inorganic materials 0.000 description 5
- 239000010962 carbon steel Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000009472 formulation Methods 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 239000000378 calcium silicate Substances 0.000 description 3
- 229910052918 calcium silicate Inorganic materials 0.000 description 3
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 3
- 230000033764 rhythmic process Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001502 supplementing effect 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
- 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
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting and a preparation method thereof, wherein raw materials are derived from deep processing of minerals and recycling of solid wastes, and compared with ferromanganese or silicon-calcium wire refining desulfurization technology and premelting preparation technology, the use cost is greatly reduced. The desulfurizing agent comprises the following components: 60-80% of ultralow-sulfur metallurgical lime powder, 10-25% of carefully chosen aluminum scraps and 10-15% of carefully chosen low-sulfur fluorite sand; the components are prepared by a non-premelting cold forming process and are subjected to passivation treatment by 0.3-0.5% of methyl silicone oil, and the granularity of the product is 5-50mm. And adding the bottom of the ladle before tapping of the converter, blowing argon, stirring, and then directly and continuously casting. In the subsequent application, when the addition amount is 5kg of desulfurizing agent per ton of steel, the sulfur content is reduced from 0.047% to 0.0119%, and the desulfurizing rate is 74.6%; meets the requirement (S percent is less than or equal to 0.020 percent) on the straight line.
Description
Technical Field
The invention relates to a low-cost high-efficiency desulfurizing agent for converter direct continuous casting and a production process thereof, belonging to the field of steelmaking desulfurizing agents.
Background
Sulfur is one of the harmful elements in steel, and its main hazard is: resulting in hot embrittlement of the steel and anisotropy of the rolled steel, the sulfur content in the steel must be severely limited.
At present, converter carbon steel at home and abroad is commonly subjected to secondary refining to deeply desulfurize molten steel, so that the sulfur content meets the quality requirement of the variety of steel before upper continuous casting. The basic process is as follows: blast furnace- & gt molten iron pretreatment- & gt converter- & gt secondary refining (LF furnace- & gt continuous casting. In order to greatly improve the production rhythm, the second steel mill of the Tai steel is to remove secondary LF furnace refining, and adopts a new process: blast furnace, molten iron pretreatment, converter and continuous casting, namely, directly adding a desulfurizing agent and supplementing a calcium silicate wire for deep desulfurization in the tapping process, and then blowing argon for stirring, and directly casting. This process has serious drawbacks: the cost is high, the desulfurization rate is only 9% -40%, and the desulfurization rate is unstable and cannot meet the requirement of direct up.
In order to improve the steel yield and reduce the cost, the converter direct continuous casting technology is adopted to produce the ordinary carbon steel, the adverse effect caused by the defect of a secondary refining process (LF furnace refining) is needed to be solved with low cost, the direct requirement that the desulfurization rate of the molten steel refining of the carbon steel is stably more than 50% and the target sulfur is lower than 0.020% is realized, and the production rhythm is further improved. In order to ensure the direct target sulfur requirement and the continuous casting billet quality and constant pulling speed production, a high-efficiency low-cost refining desulfurizing agent needs to be developed.
Disclosure of Invention
The invention aims to provide a low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting and a production process thereof, which realize deep desulfurization of molten steel, solve adverse effects caused by the lack of secondary refining procedures (LF refining), realize direct-up requirements that the desulfurization rate of carbon steel molten steel refining is stably more than 50% and the target sulfur is lower than 0.020%, and further improve the production efficiency.
The invention relates to a high-efficiency desulfurizing agent for converter direct-up continuous casting and a production process thereof, which are characterized in that raw materials are sourced from mineral deep processing and solid waste recycling, and a homogenized binder-free cold forming preparation process is adopted, so that the use cost is greatly reduced compared with ferromanganese or calcium silicate wire refining desulfurization process and premelting preparation process.
The high-efficiency desulfurizing agent has the functions of heating and warming, deoxidizing and ultralow-sulfur desulfurizing and slagging, replaces the function of a secondary refining LF furnace, greatly shortens the steelmaking process and realizes the yield improvement and synergy.
The invention relates to a method for directly casting a product on the bottom of a ladle after argon blowing and stirring after the bottom of the ladle is added before tapping of a converter.
The invention provides a low-cost high-efficiency desulfurizing agent for converter direct continuous casting, which is prepared from the following raw materials:
60-80% of ultralow-sulfur metallurgical lime powder, 10-25% of aluminum scraps and 10-15% of low-sulfur fluorite sand;
the sulfur content of the ultralow-sulfur metallurgical lime powder is less than 0.010 percent; the aluminum scraps contain more than or equal to 70 percent of metal aluminum, and the weight ratio of the aluminum oxide is 10 to 30 percent; the content of sulfur in the low-sulfur fluorite sand is 0.010 percent to less than or equal to 0.030 percent.
The invention provides a production process of the low-cost high-efficiency desulfurizing agent for converter direct continuous casting, which comprises the following steps:
(1) Obtaining low-sulfur raw materials: using mixed combustion strong oxidation technology of poplar low-sulfur anthracite and diesel oil to produce low-sulfur lime raw material with sulfur content less than 0.025%;
(2) Deep processing of raw materials: the metal aluminum scraps, the ultralow-sulfur metallurgical lime powder and the low-sulfur fluorite sand are obtained at low cost through the off-line selection and impurity removal processes respectively;
(3) The preparation of the product comprises the following steps: the obtained raw materials are prepared by the following mass percent: selecting 60-80% of ultra-low sulfur metallurgical lime powder, 10-25% of selected aluminum scraps and 10-15% of selected low sulfur fluorite sand, uniformly mixing, feeding into a high-pressure roller press by a forced feeder to roll into strips with the thickness of 100mm multiplied by 20mm multiplied by 10mm, naturally dropping into a blade crusher and a granulator to crush, screening out unqualified powder with the granularity of 5-50mm, and feeding into the roller press again to form by external circulation;
(4) And (3) product passivation: methyl silicone oil accounting for 0.3-0.5% of the total mass of the product is weighed, pressurized by a variable frequency metering pump of 0.1-0.5L/min, heated to 80-100 ℃ by a conveying pipe with a heat tracing belt, and finally subjected to surface passivation treatment by an atomization nozzle, so that moisture absorption and pulverization are reduced, the storage time of the product is ensured, and the pulverization defect of non-premelting cold forming is overcome.
Specifically, the preparation process is as follows:
the preparation process of the carefully selected ultralow-sulfur metallurgical lime powder comprises the following steps:
(1) In a 1000T/D lime rotary kiln, a mixed combustion strong oxidation technology of 90% of poplar low sulfur anthracite and 10% of diesel oil is used, the coal injection amount is 9200kg/h, the oil injection amount is 0.92kg/h, and the secondary air amount is more than 51000Nm 3 Under the working condition of/h, the low-sulfur limestone is subjected to high temperature (1250-1320 DEG C) Calcining to produce low-sulfur lime blocks A with sulfur content less than 0.025% and granularity of 10-40 mm;
(2) Crushing the low-sulfur lime blocks A with the diameter of 10-40mm by a low-speed compound crusher with the diameter of 0-15mm, and separating out blocks B with the diameter of 5-15mm and powder C with the diameter of 0-5mm under the action of a closed rolling screen; wherein the powder C contains kiln crust, slag, soil surface and the like with higher sulfur content, and is used for sintering;
(3) Crushing the lump materials B with the thickness of 5-15mm by a 0-5mm medium-speed composite crusher, and separating out ultra-low sulfur metallurgical lime powder (S% < 0.010%) with the thickness of 0-1mm and small lump materials D with the thickness of 1-5mm under the action of a cyclone dust collector; wherein the small block D contains hard kiln coating, calcined lime, sundry stone and the like with higher sulfur content, and is used for sintering.
The secondary impurity removal pretreatment process is carefully selected, and the obtained ultralow-sulfur (S% < 0.010%) metallurgical lime powder replaces common lime, so that on one hand, the content of sulfur carried in the lime is reduced, and on the other hand, the high-purity lime can realize low cost and improve the alkalinity and sulfur capacity.
The preparation process of the carefully selected low-sulfur fluorite sand comprises the following steps:
(1) Crushing fluorite ore by a jaw crusher with the diameter of 0-80mm, spreading by a forklift, and manually picking out silica and ore vein epidermis;
(2) Stirring and washing fluorite with the diameter of 0-80mm, and removing fluorite fabric with high sulfur content;
(3) Naturally airing the fluorite blocks carefully selected by the steps, wherein the sulfur content is reduced from 0.35-0.50% to 0.010-0.030%, the calcium fluoride content is increased from 85-90% to 94-96%, and the water content is reduced from more than 5% to less than 1%;
(4) And crushing the fluorite blocks with low moisture by a 0-2mm low-speed composite crusher to obtain low-sulfur fluorite sand.
The main preparation process flow of the carefully selected aluminum scraps comprises the following steps: primary aluminum slag, crushing, ball milling, screening by a closed drum screen and aluminum scraps; the method specifically comprises the following steps:
(1) Crushing primary aluminum slag into small blocks with the diameter of 0-15mm through a jaw crusher with the diameter of 0-15 mm;
(2) Grinding small blocks with the diameter of 0-15mm by an aluminum slag ball mill, and then feeding the small blocks into a closed rolling screen to separate selected aluminum scraps with the diameter of 2-15mm and secondary aluminum slag with the diameter of 0-2 mm;
(3) And delivering the secondary aluminum slag to a cement plant to be used as a rapid hardening cement CA-50 raw material.
In the process of preparing aluminum scraps, the whole system is closed, a dust hood is added, and a cyclone dust collector is arranged to ensure the working environment.
The aluminum slag (primary aluminum slag) is a product produced by cooling slag generated in the production process of electrolytic aluminum or cast aluminum, and the main components of the aluminum slag are 15% -40% of metallic aluminum w (Al), aluminum oxide, silicon dioxide and the like.
The following aims can be achieved by using aluminum scraps (containing 15% -40% of metal aluminum and 50% -70% of aluminum oxide) recovered after processing of primary aluminum slag (containing more than or equal to 70% of metal aluminum and 10% -30% of aluminum oxide): (1) the metallic aluminum can deoxidize the slag system, and provide a precondition for deep desulfurization; (2) the metal aluminum oxidation process releases heat, so that the temperature of molten steel and the desulfurization speed can be improved; (3) forming low melting point C12A7 (dodecacalcium heptaluminate) with slag system, improving desulfurization kinetics.
The desulfurizing agent production process adopts a homogenizing binder-free cold forming preparation process and a passivation treatment process to replace a premelting process, realizes cost reduction and synergy of the preparation process, and mainly comprises the following process flows: various raw materials, homogenization treatment, forced feeding, high-pressure roll forming, crushing by a blade crusher, granule shaping by a granule shaping machine, passivation and deterioration prevention; the method specifically comprises the following steps:
(1) According to the principle of closest packing, small-particle low-sulfur fluorite sand and aluminum scraps are used as aggregates, ultra-low-sulfur metallurgical lime powder is selected as a filler, the proportion of the aggregates to the powder is controlled to be 1/4 to 2/3, the aggregates and the powder are subjected to homogenization treatment by a stirrer, and the aggregates and the powder are brought into a forced feeding bin (middle bin) by a bucket elevator;
(2) Under the action of a spiral forced feeder, the volume of the fluffy material is compressed to be 1/4 of the original volume after passing through the forced feeder;
(3) Feeding the compressed material into a roller bed grinding tool of a high-pressure roller press through a forced feeder, and rolling under 15-25MPa to form strips with the thickness of 100mm multiplied by 20mm multiplied by 10 mm;
(4) Naturally falling the strip-shaped objects into a blade crusher for crushing and a cage-type granule finishing machine with the size of 0-50mm for finishing granules;
(5) Screening the crushed and sized materials by a multi-layer shaking table vibrating screen, separating out qualified granularity of 5-50mm, and enabling unqualified materials (less than 5 mm) to enter a roller press again for molding by external circulation;
(6) And (3) passivation treatment: methyl silicone oil is conveyed by a variable frequency metering pump, is heated to 80-100 ℃ by a conveying pipe with a heat tracing belt, and is subjected to surface passivation treatment by an atomization nozzle, so that moisture absorption and pulverization are reduced, the storage time of the product is ensured, and the pulverization defect of non-premelting cold forming is overcome.
The invention provides a method for using the low-cost high-efficiency desulfurizing agent for converter direct continuous casting, which comprises the following specific steps:
(1) Discharging through a top high-level bin before tapping of the converter, weighing through a metering belt, and adding into the bottom of a ladle;
(2) In the tapping process of the converter, the molten steel is impacted to form first stirring desulfurization;
(3) Stirring for 5-8 minutes by blowing Ar to form secondary stirring deep desulfurization;
(4) And after the sampling test is qualified, the crown block is hoisted to a continuous casting station.
The percentages in the invention are mass percentages.
The invention has the beneficial effects that:
(1) The raw materials are from mineral deep processing and solid waste recycling, and compared with ferromanganese or calcium silicate wire refining desulfurization and premelting processes, the homogenized binder-free cold forming preparation process is adopted, so that the production and use cost is greatly reduced.
(2) The invention relates to a product, which has the functions of heating and warming, deoxidizing, ultralow sulfur desulfurization and slagging, replaces the function of a secondary refining LF furnace, greatly shortens the steelmaking process and realizes the production and synergy.
(3) The invention relates to a method for directly casting a product on the bottom of a ladle after argon blowing and stirring after the product is added to the bottom of the ladle before tapping of a converter; when the addition amount of the desulfurizing agent is 5 kg/ton of steel, the sulfur content is reduced from 0.047% to 0.0119%, and the desulfurizing rate is 74.6%; when the addition amount of the desulfurizing agent is 2.5 kg/ton of steel, the average sulfur content is reduced from 0.0295% to 0.0131%, and the desulfurizing rate is 54.9%; the invention adopts low-cost desulfurizing agent to solve the adverse effect caused by the defect of secondary refining process (LF furnace refining), realizes stable desulfurization rate of more than 50% in carbon steel molten steel refining, and meets the requirement of S less than or equal to 0.020% in the straight-up process, thereby improving the production rhythm.
Drawings
FIG. 1 is a process flow diagram of the invention for preparing ultra-low sulfur metallurgical lime powder;
FIG. 2 is a flow chart of a process for preparing beneficiated low sulfur fluorite sand in accordance with the present invention;
FIG. 3 is a flow chart of a process for preparing beneficiated aluminum flake in accordance with the present invention;
FIG. 4 is a flow chart of a production process for preparing the low-cost high-efficiency desulfurizing agent.
Detailed Description
The present invention is further illustrated by, but not limited to, the following examples.
Example 1
A production process for preparing a low-cost high-efficiency desulfurizing agent comprises the following specific processes:
(1) The production process shown in figures 1, 2 and 3 is used for respectively obtaining carefully chosen ultralow-sulfur metallurgical lime powder, carefully chosen aluminum scraps and carefully chosen low-sulfur fluorite sand. The main physical and chemical indexes are shown in the following table 1;
TABLE 1
(2) The formula 1 of the high-efficiency desulfurizing agent is designed, and the formula comprises the following components: selecting 60% of ultra-low sulfur metallurgical lime powder, 25% of aluminum scraps, 15% of low sulfur fluorite sand, controlling the proportion of granule materials to powder materials to be 2/3, carrying out homogenization treatment by a stirrer, and carrying the mixture into a forced feeding bin (middle bin) by a bucket elevator.
(3) After the fluffy material passes through a forced feeder, the volume is compressed to be 1/4 of that of the original fluffy material, the fluffy material is fed into a roller press grinding tool, and rolled into strips with the thickness of 100mm multiplied by 20mm multiplied by 10mm under the pressure of 22 MPa.
(4) The strip-shaped objects naturally fall into a blade crusher to be crushed and are granulated by a cage granulator with the diameter of 0-50 mm. The crushed and sized materials are screened by a multi-layer shaking table vibrating screen, and qualified granularity of 5-50mm is separated.
(5) After the components are prepared by a non-premelting cold forming process, the finished product is subjected to 0.4% methyl silicone oil passivation treatment according to the production process of fig. 4, and is packed for standby. Is denoted as desulfurizing agent 1.
The low-cost high-efficiency desulfurizing agent 1 prepared by the invention is used for converter direct continuous casting, and the application process is as follows:
1) Discharging through a top high-level bin before tapping of the converter, weighing through a metering belt, and adding into the bottom of a ladle;
2) In the tapping process of the converter, the molten steel is impacted to form first stirring desulfurization;
3) Stirring for 6 minutes by blowing Ar to form secondary stirring deep desulfurization;
4) After the sampling test is qualified, the crown block is hoisted to a continuous casting station
Test effect: the addition amount of 5 kg/ton of steel is reduced from 0.047% to 0.0119%, the desulfurization rate is 74.6%, and the requirement of the direct up (S is less than or equal to 0.020%) is met; from the slag sample, the newly developed desulfurizing agent 1 has good adsorption effect on S, promotes S to separate from molten steel and enters steel slag. Specific data are shown in tables 2 and 3.
Table 2, formulation 1 furnace time data before and after test
Table 3, slag sample comparison data before and after formulation 1 test
Example 2
A production process for preparing a low-cost high-efficiency desulfurizing agent comprises the following specific processes:
(1) The production process shown in figures 1, 2 and 3 is used for respectively obtaining carefully chosen ultralow-sulfur metallurgical lime powder, carefully chosen aluminum scraps and carefully chosen low-sulfur fluorite sand. The main physicochemical indexes are shown in the following table 4;
TABLE 4 Table 4
(2) The formula 2 of the high-efficiency desulfurizing agent is designed, and the formula comprises the following components: selecting 70% of ultra-low sulfur metallurgical lime powder, selecting 15% of aluminum scraps and selecting 15% of low sulfur fluorite sand; the proportion of the granule material to the powder material is controlled to be 3/7, the granule material and the powder material are subjected to homogenization treatment by a stirrer and are brought into a forced feeding bin (middle bin) by a bucket elevator.
(3) After the fluffy material passes through a forced feeder, the volume is compressed to be 1/4 of that of the original fluffy material, the fluffy material is fed into a roller press grinding tool, and rolled into strips with the thickness of 100mm multiplied by 20mm multiplied by 10mm under the pressure of 22 MPa.
(4) The strip-shaped objects naturally fall into a blade crusher to be crushed and are granulated by a cage granulator with the diameter of 0-50 mm. The crushed and sized materials are screened by a multi-layer shaking table vibrating screen, and qualified granularity of 5-50mm is separated.
(5) After the components are prepared by a non-premelting cold forming process, the finished product is subjected to 0.4% methyl silicone oil passivation treatment according to the production process of fig. 4, and is packed for standby. Is denoted as desulfurizing agent 2.
The low-cost high-efficiency desulfurizing agent 2 prepared by the invention is used for converter direct continuous casting, and the application process is as follows:
1) Discharging through a top high-level bin before tapping of the converter, weighing through a metering belt, and adding into the bottom of a ladle;
2) In the tapping process of the converter, the molten steel is impacted to form first stirring desulfurization;
3) Stirring for 7 minutes by blowing Ar to form a second stirring deep desulfurization;
4) And after the sampling test is qualified, the crown block is hoisted to a continuous casting station.
Test effect: the addition amount is 2.5 kg/ton of steel, the average sulfur content is reduced from 0.0295% to 0.0131%, and the desulfurization rate is 54.9%; all meet the requirement of straight up (S is less than or equal to 0.020%). From the slag sample, the newly developed desulfurizing agent 2 also has good adsorption effect on S, and promotes S to be separated from molten steel and enter steel slag. The specific data are shown in tables 5 and 6.
Table 5, formulation 2 post-test oven times data
Table 6, comparative data for slag sample after formulation 2 test
。
Claims (7)
1. The low-cost high-efficiency desulfurizing agent for converter direct continuous casting is characterized by being prepared from the following raw materials:
60-80% of ultralow-sulfur metallurgical lime powder, 10-25% of aluminum scraps and 10-15% of low-sulfur fluorite sand;
the sulfur content of the ultralow-sulfur metallurgical lime powder is less than 0.010 percent; the aluminum scraps contain more than or equal to 70 percent of metal aluminum, and the weight ratio of the aluminum oxide is 10 to 30 percent; the content of sulfur in the low-sulfur fluorite sand is 0.010 percent to less than or equal to 0.030 percent.
2. A process for producing a low-cost and high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following specific steps:
(1) Obtaining low-sulfur raw materials: using mixed combustion strong oxidation technology of poplar low-sulfur anthracite and diesel oil to produce low-sulfur lime raw material with sulfur content less than 0.025%;
(2) Deep processing of raw materials: the metal aluminum scraps, the ultralow-sulfur metallurgical lime powder and the low-sulfur fluorite sand are obtained at low cost through the off-line selection and impurity removal processes respectively;
(3) The preparation of the product comprises the following steps: the obtained raw materials are prepared by the following mass percent: selecting 60-80% of ultra-low sulfur metallurgical lime powder, 10-25% of selected aluminum scraps and 10-15% of selected low sulfur fluorite sand, uniformly mixing, feeding into a high-pressure roller press by a forced feeder to roll into strips with the thickness of 100mm multiplied by 20mm multiplied by 10mm, naturally dropping into a blade crusher and a granulator to crush, screening out unqualified powder with the granularity of 5-50mm, and feeding into the roller press again to form by external circulation;
(4) And (3) product passivation: methyl silicone oil accounting for 0.3-0.5% of the total mass of the product is weighed, pressurized by a variable frequency metering pump of 0.1-0.5L/min, heated to 80-100 ℃ by a conveying pipe with a heat tracing belt, and finally subjected to surface passivation treatment by an atomization nozzle, so that moisture absorption and pulverization are reduced, the storage time of the product is ensured, and the pulverization defect of non-premelting cold forming is overcome.
3. The production process of the low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following steps of: the preparation process of the ultralow-sulfur metallurgical lime powder comprises the following steps:
(1) In a 1000T/D lime rotary kiln, a mixed combustion strong oxidation technology of 90% of poplar low sulfur anthracite and 10% of diesel oil is used, the coal injection amount is 9200kg/h, the oil injection amount is 0.92kg/h, and the secondary air amount is more than 51000Nm 3 Under the working condition of/h, calcining the low-sulfur limestone at a high temperature of 1250-1320 ℃ to produce low-sulfur lime blocks A with sulfur content less than 0.025% and granularity of 10-40 mm;
(2) Crushing the low-sulfur lime blocks A with the diameter of 10-40mm by a low-speed compound crusher with the diameter of 0-15mm, and separating out blocks B with the diameter of 5-15mm and powder C with the diameter of 0-5mm under the action of a closed rolling screen; wherein the powder C contains a kiln crust, slag and soil surface with higher sulfur content for sintering;
(3) Crushing the lump materials B with the thickness of 5-15mm by a 0-5mm medium-speed composite crusher, and separating out 0-1mm ultralow-sulfur metallurgical lime powder and 1-5mm small lump materials D under the action of a cyclone dust collector; wherein the small block D contains a hard kiln shell with higher sulfur content, calcined lime and sundry stone for sintering.
4. The production process of the low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following steps of: the preparation process of the low-sulfur fluorite sand comprises the following steps:
(1) Crushing fluorite ore by a jaw crusher with the diameter of 0-80mm, spreading by a forklift, and manually picking out silica and ore vein epidermis;
(2) Stirring and washing fluorite with the diameter of 0-80mm, and removing fluorite fabric with high sulfur content;
(3) Naturally airing the fluorite blocks carefully selected by the steps, wherein the sulfur content is reduced from 0.35-0.50% to 0.010-0.030%, the calcium fluoride content is increased from 85-90% to 94-96%, and the water content is reduced from more than 5% to less than 1%;
(4) And crushing the fluorite blocks with low moisture by a 0-2mm low-speed composite crusher to obtain low-sulfur fluorite sand.
5. The production process of the low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following steps of: the main preparation process flow of the aluminum scraps comprises the following steps: primary aluminum slag, crushing, ball milling, screening by a closed drum screen and aluminum scraps; the method specifically comprises the following steps:
(1) Crushing primary aluminum slag into small blocks with the diameter of 0-15mm through a jaw crusher with the diameter of 0-15 mm;
(2) Grinding small blocks with the diameter of 0-15mm by an aluminum slag ball mill, and then feeding the small blocks into a closed rolling screen to separate selected aluminum scraps with the diameter of 2-15mm and secondary aluminum slag with the diameter of 0-2 mm;
(3) And delivering the secondary aluminum slag to a cement plant to be used as a rapid hardening cement CA-50 raw material.
6. The production process of the low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following steps of:
(1) According to the principle of closest packing, small-particle low-sulfur fluorite sand and aluminum scraps are used as aggregates, ultra-low-sulfur metallurgical lime powder is selected as a filler, the proportion of the aggregates to the powder is controlled to be 1/4 to 2/3, the aggregates and the powder are subjected to homogenization treatment by a stirrer, and the aggregates and the powder are brought into a forced feeding bin by a bucket elevator;
(2) Under the action of a spiral forced feeder, the volume of the fluffy material is compressed to be 1/4 of the original volume after passing through the forced feeder;
(3) Feeding the compressed material into a roller bed grinding tool of a high-pressure roller press through a forced feeder, and rolling under 15-25MPa to form strips with the thickness of 100mm multiplied by 20mm multiplied by 10 mm;
(4) Naturally falling the strip-shaped objects into a blade crusher for crushing and a cage-type granule finishing machine with the size of 0-50mm for finishing granules;
(5) Screening the crushed and sized materials by a multi-layer shaking table vibrating screen, separating out qualified granularity of 5-50mm, and enabling unqualified materials to enter a roller press again for molding by external circulation;
(6) And (3) passivation treatment: methyl silicone oil is conveyed by a variable frequency metering pump, is heated to 80-100 ℃ by a conveying pipe with a heat tracing belt, and is subjected to surface passivation treatment by an atomization nozzle, so that moisture absorption and pulverization are reduced, the storage time of the product is ensured, and the pulverization defect of non-premelting cold forming is overcome.
7. The method for using the low-cost high-efficiency desulfurizing agent for converter direct-up continuous casting, which is characterized by comprising the following specific steps:
(1) Discharging through a top high-level bin before tapping of the converter, weighing through a metering belt, and adding into the bottom of a ladle;
(2) In the tapping process of the converter, the molten steel is impacted to form first stirring desulfurization;
(3) Stirring for 5-8 minutes by blowing Ar to form secondary stirring deep desulfurization;
(4) And after the sampling test is qualified, the crown block is hoisted to a continuous casting station.
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