CN115627322B - Desulfurizing agent for RH furnace and preparation method thereof - Google Patents
Desulfurizing agent for RH furnace and preparation method thereof Download PDFInfo
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- CN115627322B CN115627322B CN202211342197.8A CN202211342197A CN115627322B CN 115627322 B CN115627322 B CN 115627322B CN 202211342197 A CN202211342197 A CN 202211342197A CN 115627322 B CN115627322 B CN 115627322B
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- 230000003009 desulfurizing effect Effects 0.000 title claims abstract description 123
- 238000002360 preparation method Methods 0.000 title claims abstract description 19
- 229910004261 CaF 2 Inorganic materials 0.000 claims abstract description 34
- 238000000034 method Methods 0.000 claims abstract description 20
- 239000003795 chemical substances by application Substances 0.000 claims description 94
- 238000001816 cooling Methods 0.000 claims description 85
- 238000010438 heat treatment Methods 0.000 claims description 34
- 239000000203 mixture Substances 0.000 claims description 34
- 238000006243 chemical reaction Methods 0.000 claims description 29
- 239000000843 powder Substances 0.000 claims description 28
- 238000004321 preservation Methods 0.000 claims description 26
- 239000002994 raw material Substances 0.000 claims description 25
- 239000007788 liquid Substances 0.000 claims description 20
- 238000003723 Smelting Methods 0.000 claims description 18
- 238000002844 melting Methods 0.000 claims description 17
- 230000008018 melting Effects 0.000 claims description 17
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 9
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 9
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 9
- 239000010436 fluorite Substances 0.000 claims description 9
- 239000004571 lime Substances 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 8
- 239000011812 mixed powder Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 4
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 4
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 4
- 230000008569 process Effects 0.000 abstract description 16
- 239000012071 phase Substances 0.000 description 58
- 230000000052 comparative effect Effects 0.000 description 22
- 229910000831 Steel Inorganic materials 0.000 description 11
- 239000010959 steel Substances 0.000 description 11
- 238000006477 desulfuration reaction Methods 0.000 description 9
- 230000023556 desulfurization Effects 0.000 description 9
- 229910000976 Electrical steel Inorganic materials 0.000 description 5
- 229910052500 inorganic mineral Inorganic materials 0.000 description 4
- 239000011707 mineral Substances 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000010128 melt processing Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- LDXJRKWFNNFDSA-UHFFFAOYSA-N 2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound C1CN(CC2=NNN=C21)CC(=O)N3CCN(CC3)C4=CN=C(N=C4)NCC5=CC(=CC=C5)OC(F)(F)F LDXJRKWFNNFDSA-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000005307 ferromagnetism Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The application provides a desulfurizing agent for RH furnaces and a preparation method thereof, wherein the desulfurizing agent for RH furnaces comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent. The desulfurizing agent for the RH furnace provided by the application can reduce the addition amount of the desulfurizing agent in the desulfurizing process, shorten the desulfurizing time and improve the desulfurizing rate.
Description
Technical Field
The application relates to the technical field of steel smelting, in particular to a desulfurizing agent for an RH furnace and a preparation method thereof.
Background
Sulfur in steel is generally considered as a detrimental inclusion, wherein the sulfur content has a major impact on the ferromagnetism of the silicon steel product, and therefore, developing a lower sulfur content silicon steel to increase its magnetic permeability and reduce core loss is an important direction for optimizing the silicon steel product. The production process flow of the silicon steel commonly adopted at the present stage is as follows: converter-RH furnace-continuous casting, wherein the desulfurization process is performed in the RH furnace at a later stage. In the prior desulfurization process, the problems of large addition amount of the desulfurizing agent, long required desulfurizing time, large temperature drop and the like generally exist due to the limitation of the self performance of the conventional desulfurizing agent, so that the desulfurization process becomes a limiting link of silicon steel production and technology. Therefore, there is a need to develop a more effective RH furnace desulfurizing agent to solve the above problems.
Disclosure of Invention
Based on the above, the application provides the desulfurizing agent for the RH furnace and the preparation method thereof, which can reduce the addition amount of the desulfurizing agent in the desulfurizing process, shorten the desulfurizing time and improve the desulfurizing rate.
The first aspect of the application provides a desulfurizing agent for RH furnaces, which comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent.
According to any one of the embodiments of the first aspect of the present application, the desulfurizing agent for the RH furnace comprises the following components in percentage by mass: caO,35% -50%; caF (CaF) 2 ，5％～35％；Al 2 O 3 ，20％～38％；SiO 2 ，1％～8％；MgO≤8％；TiO 2 ≤0.1％；C≤0.15％；S≤0.1％。
According to any one of the embodiments of the first aspect of the present application, the desulfurizing agent for an RH furnace satisfies at least one of the following conditions:
(1) In the desulfurizing agent for RH furnace, the content of 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is 30% -80%;
(2) The average grain diameter of the desulfurizing agent for the RH furnace is 3 mm-50 mm.
The second aspect of the application provides a method for preparing a desulfurizing agent for an RH furnace, comprising the following steps:
providing a reaction raw material;
carrying out melting treatment on the reaction raw materials to obtain a liquid mixture;
the liquid mixture is crushed after being subjected to sectional heat treatment to obtain the desulfurizing agent for the RH furnace,
wherein the desulfurizing agent for RH furnace comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent.
According to any embodiment of the second aspect of the present application, the staged heat treatment comprises:
a first heat treatment stage, comprising the step of carrying out heat preservation treatment on the liquid mixture at a first temperature to obtain a heat preservation treated matter;
and the second heat treatment stage comprises the step-by-step cooling treatment of the heat preservation treatment substance to obtain a blocky desulfurizing agent for the RH furnace.
According to any one of the embodiments of the second aspect of the present application, the preparation method satisfies at least one of the following conditions:
(1) The first temperature is above 800 ℃, and is optionally 800-1300 ℃;
(2) The heat preservation treatment time is more than 24 hours, and can be selected to be 24-30 hours.
According to any one of the embodiments of the second aspect of the present application, the step-wise cooling treatment for the heat-preserving treatment object includes:
a first cooling treatment step, which comprises cooling the heat-preserving treatment object at a first cooling rate in a second temperature interval to obtain a first cooling treatment object;
a second cooling treatment step, including cooling the first cooling treatment object at a second cooling rate in a third temperature interval to obtain a second cooling treatment object;
and a third cooling treatment step, wherein the second cooling treatment object is cooled at a third cooling rate in a fourth temperature interval to obtain the block-shaped desulfurizing agent for the RH furnace.
According to any one of the embodiments of the second aspect of the present application, the preparation method satisfies at least one of the following conditions:
(1) The second temperature range is 500-800 ℃;
(2) The third temperature range is 300-500 ℃;
(3) The fourth temperature range is 25-300 ℃.
According to any one of the embodiments of the second aspect of the present application, the preparation method satisfies at least one of the following conditions:
(1) The first cooling rate is more than 150 ℃/h, and is optionally 150 ℃/h to 250 ℃/h;
(2) The second cooling rate is more than 80 ℃/h, and can be selected to be 80 ℃/h to 180 ℃/h;
(3) The third cooling rate is more than 40 ℃/h, and can be selected to be 40 ℃/h to 70 ℃/h.
According to any one of the embodiments of the second aspect of the present application, the reaction raw material comprises a mixed powder of lime powder, fluorite powder and alumina powder, optionally, the mixed powder has an average particle diameter of 0.075mm to 0.300mm.
According to any one of the embodiments of the second aspect of the present application, the melt processing of the reaction raw material includes:
smelting the reaction raw materials to obtain a smelting mixture;
heating the smelting mixture to 1400-1550 ℃ and then preserving heat for more than 15min, and optionally 15-30 min.
The desulfurizing agent provided by the application comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 Phase, and the 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent. The sum of the mass percentages of two phases in the desulfurizing agent is accurately regulated to be more than 30%, so that the melting point of the desulfurizing agent can be reduced, the desulfurizing agent can be melted as soon as possible and react with molten steel as soon as possible, and further, the higher desulfurizing rate can be obtained under the condition of the same desulfurizing agent addition in the desulfurizing process, and the desulfurizing rate can reach 60% -85%, thereby improving the desulfurizing efficiency, reducing the desulfurizing time and reducing the cost.
Detailed Description
In order that the application may be understood, a more complete description of the application will be rendered by way of example. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
For simplicity, only a few numerical ranges are explicitly disclosed. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each point or individual value between the endpoints of the range is included within the range, although not explicitly recited. Thus, each point or individual value may be combined as a lower or upper limit on itself with any other point or individual value or with other lower or upper limit to form a range that is not explicitly recited.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It is noted that, as used herein, unless otherwise indicated, the term "and/or" includes any and all combinations of one or more of the associated listed items, "above," below, "and" comprise the present number, and the meaning of "multiple" in "one or more" is two or more.
The above summary of the present application is not intended to describe each disclosed embodiment or every implementation of the present application. The following description more particularly exemplifies illustrative embodiments. Guidance is provided throughout this application by a series of embodiments, which may be used in various combinations. In the various examples, the list is merely a representative group and should not be construed as exhaustive.
The inventor finds that the mineral phase components and the content in the desulfurizing agent have larger influence on the melting point of the desulfurizing agent in the research process, and the melting point of the desulfurizing agent with lower melting point can accelerate the melting of the desulfurizing agent, so that the desulfurizing agent is liquefied and fully mixed with molten steel to react as soon as possible to obtain higher desulfurizing rate. Accordingly, the present application has been made in view of the above-described findings of the inventors and has proposed the following means.
According to a first aspect of the embodiment of the application, there is provided a desulfurizing agent for RH furnaces, comprising 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent.
The desulfurizing agent for RH furnace provided by the application comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 The inventor surprisingly found in the research process that when the sum of the mass percentages of the two phases is controlled to be more than 30%, the melting point of the desulfurizing agent can be effectively reduced, so that the desulfurizing rate can be higher under the condition of the same desulfurizing agent addition amount in the desulfurizing process, and the desulfurizing rate can reach 60% -85%. The desulfurizing agent for RH furnace has short stay time in the vacuum chamber and no desulfurizing effect after leaving the vacuum chamber, so that the melting point of the desulfurizing agent is lowered to some extent and the desulfurizing rate of the desulfurizing agent is raised by controlling the mass percentage of the two phases to over 30% to raise the desulfurizing rate.
In some embodiments, in the desulfurizing agent for RH furnace, the 12CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is 30-80%. For example, the 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases may be 40%,50%,60%,70% or within the range of any of the above values.
In some embodiments, the desulfurizing agent for the RH furnace comprises the following components in percentage by mass: caO,35% -50%; caF (CaF) 2 ，5％～35％；Al 2 O 3 ，20％～38％；SiO 2 ，1％～8％；MgO≤8％；TiO 2 ≤0.1％；C≤0.15％；S≤0.1％。
In an embodiment of the present application, the desulfurizing agent comprisesThe components are controlled in proper ranges in percentage by mass, which is favorable for forming 12 CaO.7Al in the desulfurizing agent 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 And simultaneously controlling the sum of the mass percentages of the two phases within a proper range required by the application.
In some embodiments, the desulfurizing agent for RH furnaces has an average particle size of 3mm to 50mm. For example, the average particle size of the desulfurizing agent for RH furnaces may be 5mm,10mm,20mm,30mm,40mm or within a range composed of any of the above values.
The second aspect of the embodiment of the application provides a preparation method of a desulfurizing agent for an RH furnace, which comprises the following steps:
s10, providing a reaction raw material;
s20, carrying out melting treatment on the reaction raw materials to obtain a liquid mixture;
s30, carrying out sectional heat treatment on the liquid mixture, and crushing to obtain the desulfurizing agent for the RH furnace, wherein the desulfurizing agent for the RH furnace comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30 percent.
The preparation method provided by the application comprises a step of sectional heat treatment of the liquid mixture, wherein the components and the mineral phases of the desulfurizing agent for the RH furnace can be accurately regulated and controlled through the sectional heat treatment, so that the components and the mineral phases of the desulfurizing agent are optimized, and 12CaO 7Al is finally formed in the desulfurizing agent through the proper regulation and control of corresponding parameters in the sectional heat treatment and the mutual coordination of the parameters 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 Simultaneously, the sum of the mass percentages of the two ore phases can be controlled to be more than 30 percent.
In some embodiments, the reaction raw materials in step S10 include a mixed powder of lime powder, fluorite powder and alumina powder.
In some embodiments, the average particle size of the powder blend is from 0.075mm to 0.300mm. For example, the average particle size of the powder mix may be 0.095mm,0.115mm,0.135mm,0.155mm,0.175mm,0.195mm,0.215mm,0.235mm,0.255mm,0.275mm,0.295mm or within the range of any of the above values.
Specifically, in step S10, lime, fluorite and alumina (metallurgical grade) may be milled to 50-200 mesh (0.075-0.300 mm) by using a ball mill or other milling equipment, so as to form lime powder, fluorite powder and alumina powder, and the particle sizes of the lime powder, fluorite powder and alumina powder are kept consistent or close as much as possible; and then adding lime powder, fluorite powder and alumina powder into a mixing bin according to a certain proportion according to actual requirements, and uniformly mixing to form mixed powder. Preferably, the lime powder, fluorite powder and alumina powder may be added in divided portions uniformly in the target component ratio.
In some embodiments, the step S20 of melt-processing the reaction raw materials includes the steps of:
s200, smelting the reaction raw materials to obtain a smelting mixture;
s210, heating the smelting mixture to 1400-1550 ℃, and then preserving heat for more than 15min, and optionally 15-30 min.
Specifically, the reaction raw materials can be added into an electric furnace, the temperature of the electric furnace is increased to 1400-1550 ℃, and smelting is carried out simultaneously in the heating process, so as to obtain a smelting mixture; and then preserving the temperature of the smelting mixture for more than 15 minutes to obtain a liquid mixture, and stirring the liquid mixture by adopting gas to ensure that the liquid mixture is uniform. Preferably, in the gas stirring, nitrogen or argon may be used as the gas.
In the melting treatment process, the smelting mixture is heated to 1400-1550 ℃ and then is kept for more than 15min, so that the reaction raw materials are fully mixed for reaction, and the reaction is conducted to generate 12CaO 7Al through the regulation and control of the temperature 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 The phase direction proceeds.
In some embodiments, the step S30 of the staged heat treatment may include the steps of:
s300, performing a first heat treatment stage, namely performing heat preservation treatment on the liquid mixture at a first temperature to obtain a heat preservation treated matter;
s310, performing a second heat treatment stage, namely performing step-by-step cooling treatment on the heat preservation treatment object to obtain a block-shaped desulfurizing agent for the RH furnace.
Specifically, in step S30, the liquid mixture may be poured into an iron container, and heat preservation is performed for a certain time to obtain a heat preservation treated product; then the heat preservation treatment object is cooled to normal temperature in a sectionalized way by adopting a blowing cooling mode, and the large solid desulfurizing agent for the RH furnace is obtained.
In some embodiments, the first temperature is 800 ℃ or higher and the incubation time is 24 hours or longer. Optionally, the first temperature is 800-1300 ℃, and the heat preservation treatment time is 24-30 h.
The heat preservation process in the first heat treatment stage can promote the amorphous phase formed in the liquid phase cooling process to be converted into 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 The phase transition mainly occurs between 800 ℃ and 1200 ℃. When the temperature is lower than 800 ℃, the temperature needs to be reduced as soon as possible to ensure 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 Stability of the phases.
In some embodiments, the step of cooling the heat-preserving treatment object in step S310 may include the following steps:
s3100, a first cooling treatment step, which comprises cooling the heat-preserving treatment object at a first cooling rate in a second temperature interval to obtain a first cooling treatment object;
s3110, a second cooling treatment step, including cooling the first cooling treatment object at a second cooling rate in a third temperature interval to obtain a second cooling treatment object;
s3120, a third cooling treatment step, which comprises cooling the second cooling treatment object at a third cooling rate in a fourth temperature interval to obtain the block-shaped desulfurizing agent for the RH furnace.
In some embodiments, the second temperature interval is 500 ℃ to 800 ℃.
In some embodiments, the first cooling rate is 150 ℃/h or more. For example, the first cooling rate may be 160 ℃/h,170 ℃/h,180 ℃/h,190 ℃/h, 200 ℃/h, or the like. Optionally, the first cooling rate is 150 ℃/h to 250 ℃/h.
In some embodiments, the third temperature range is 300 ℃ to 500 ℃.
In some embodiments, the second cooling rate is 80 ℃/h or more. The second cooling rate may be 90 ℃/h,100 ℃/h,110 ℃/h,120 ℃/h, 130 ℃/h, or the like. Optionally, the second cooling rate is 80 ℃/h to 180 ℃/h.
In some embodiments, the fourth temperature range is 25 ℃ to 300 ℃.
In some embodiments, the third cooling rate is 40 ℃/h or greater. For example, the first cooling rate may be 50 ℃/h,60 ℃/h, 70 ℃/h, or the like. Optionally, the third cooling rate is 40 ℃/h to 70 ℃/h.
The sectional cooling treatment process can promote the conversion of the amorphous phase formed in the liquid phase cooling process into 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 The phase transition mainly occurs between 800 ℃ and 1200 ℃. When the temperature is lower than 800 ℃, the temperature needs to be reduced as soon as possible to ensure 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 Stability of the phases.
Thus, in the production method provided by the application, 12 CaO.7Al can be formed in the produced desulfurizing agent by the mutual cooperation of the reaction parameters in the melting treatment and the sectional heat treatment 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the two phases can be regulated to be more than 30 percent.
In some embodiments, after the block-shaped desulfurizing agent for RH furnace is obtained in step S310, the block-shaped desulfurizing agent for RH furnace is further subjected to a crushing treatment.
Specifically, the block-shaped desulfurizing agent for the RH furnace can be manually and preliminarily crushed into small single blocks with the size capable of entering a jaw crusher, and then the small blocks are put into the jaw crusher to be crushed to the required granularity, generally 3-50 mm, so as to obtain desulfurizing agent blocks for the RH furnace; and then putting the desulfurizer small blocks for the RH furnace into a ball mill or other grinding equipment to grind into fine powder, wherein the granularity of the fine powder can be controlled according to actual requirements.
In some embodiments, the desulfurizing agent for the RH furnace has a melting point of about 1080 ℃ to about 1280 ℃.
Examples
The present disclosure is more particularly described in the following examples that are intended as illustrations only, since numerous modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the examples below are by weight, and all reagents used in the examples are commercially available or were obtained synthetically according to conventional methods and can be used directly without further treatment, as well as the instruments used in the examples.
Example 1
A preparation method of a desulfurizing agent for an RH furnace comprises the following steps: melting the reaction raw materials, heating to 1400-1550 ℃ and preserving heat for 15min to obtain a liquid mixture; the liquid mixture is subjected to sectional heat treatment and then crushed to obtain the desulfurizing agent for the RH furnace, and then the liquid mixture is subjected to sectional temperature and temperature reduction treatment, and the specific details are shown in table 1. The desulfurizing agents for RH furnaces with different components and ore phase ratios in Table 2 were obtained.
The desulfurizing agent for RH furnace is used in molten steel desulfurization treatment, and after deoxidization and alloying of molten steel are completed, 5 kg-10 kg of desulfurizing agent for RH furnace is added into molten steel per ton of molten steel (the specific addition amount and desulfurization rate are shown in table 3), so that the desulfurization rate of 60% -85% is obtained.
Examples 2 to 10
The preparation of examples 2-10 was similar to the examples except that the ingredients and process parameters in the preparation were changed as shown in tables 1 and 2 below.
Comparative example 1
The preparation of comparative example 1 was similar to that of example 1, except that: the second heat treatment stage, i.e. the cooling to room temperature in one step after the heat preservation treatment, is omitted.
Comparative example 2
The preparation of comparative example 2 was similar to that of example 1, except that: the first heat treatment stage is omitted, namely, the heat preservation treatment is not carried out after the reaction raw materials are melted.
Comparative example 3
The preparation of comparative example 3 was similar to that of example 1, except that: the first heat treatment stage is omitted, namely, the reaction raw materials are not subjected to heat preservation treatment after being melted, and are directly cooled to room temperature in one step.
Comparative example 4
The molten steel is desulfurized by using a conventional desulfurizing agent.
The process parameters for preparing the desulfurizing agent for RH furnace in examples 1 to 10 and comparative examples 1 to 4 and the conditions parameters related to the desulfurizing agent for RH furnace used in the desulfurizing treatment of molten steel are shown in tables 1 to 3 below.
TABLE 1
TABLE 2
TABLE 3 Table 3
| Molten steel amount (mt) | Desulfurizing agent addition amount (kg) | Desulfurization rate (%) | |
| Example 1 | 180 | 1252 | 69.4 |
| Example 2 | 180 | 1631 | 72.3 |
| Example 3 | 180 | 1565 | 80.4 |
| Example 4 | 180 | 1159 | 75.2 |
| Example 5 | 180 | 1543 | 75.2 |
| Example 6 | 180 | 1535 | 84.1 |
| Example 7 | 180 | 1718 | 79.9 |
| Example 8 | 180 | 903 | 79.6 |
| Example 9 | 180 | 1272 | 64.8 |
| Example 10 | 180 | 1193 | 69.4 |
| Comparative example 1 | 180 | 1721 | 47.2 |
| Comparative example 2 | 180 | 1141 | 48.8 |
| Comparative example 3 | 180 | 1191 | 42.9 |
| Comparative example 4 | 180 | 1556 | 55.4 |
In tables 1 and 2, it is clear that, in the case where the respective components and the corresponding contents in the desulfurizing agent for RH furnace are equal, 12 CaO.7Al in the desulfurizing agent for RH furnace obtained after the first heat treatment stage or the second heat treatment stage is omitted from comparative examples 1 and 1, example 2 and comparative example 2, and example 3 and comparative example 3 2 O 3 And 11 CaO.7Al 2 O 3 ·CaF 2 The content of the ore phases is obviously reduced, and the total content of the two ore phases is lower than 30 percent, which indicates that the sectional heat treatment is carried out on 12 CaO.7Al 2 O 3 And 11 CaO.7Al 2 O 3 ·CaF 2 The formation of mineral phases has a major impact.
In Table 3, it is found that in comparative example 3 and comparative example 4, in the case where the addition amount of the desulfurizing agent is substantially equivalent, the desulfurizing rate in example 3 is significantly higher than that in comparative example 4, indicating that 12 CaO.7Al is produced by the method of the present application as compared with the conventional desulfurizing agent 2 O 3 And 11 CaO.7Al 2 O 3 ·CaF 2 The desulfurizing agent with the ore phase content higher than 30% can indeed greatly improve the desulfurizing rate, and has better desulfurizing effect. Comparative example 7 and comparative example 1, example 4 and comparative example 2, and example 10 and comparative example 3, it is understood that, in the case where the addition amount of the desulfurizing agent is substantially equivalent, 12 CaO.7Al in the desulfurizing agent 2 O 3 And 11 CaO.7Al 2 O 3 ·CaF 2 When the content of the ore phase is lower than 30%, the desulfurization rate is obviously lower, which means that 12 CaO.7Al in the desulfurizing agent is used for obtaining higher desulfurization rate 2 O 3 And 11 CaO.7Al 2 O 3 ·CaF 2 The content of the ore phase is more than 30%. The technical features of the above embodiments may be combined arbitrarily, and for brevity of description, not all of the possible groups of the technical features of the above embodimentsHowever, the combinations of these technical features should be regarded as the scope of the present description, as long as there is no contradiction.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (7)
1. A desulfurizing agent for RH furnace is characterized by comprising 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30%, and the desulfurizing agent for the RH furnace comprises the following components in percentage by mass: caO,35% -50%; caF (CaF) 2 ，5%~35%；Al 2 O 3 ，20%~38%；SiO 2 ，1%~8%；MgO≤8%；TiO 2 ≤0.1%；C≤0.15%；S≤0.1%；
The preparation method of the desulfurizing agent for the RH furnace comprises the following steps:
providing a reaction raw material, wherein the reaction raw material comprises mixed powder of lime powder, fluorite powder and alumina powder;
carrying out melting treatment on the reaction raw materials to obtain a liquid mixture;
carrying out sectional heat treatment on the liquid mixture, and then crushing to obtain a desulfurizing agent for the RH furnace;
wherein the melting treatment of the reaction raw materials comprises the following steps:
smelting the reaction raw materials to obtain a smelting mixture;
heating the smelting mixture to 1400-1550 ℃ and then preserving heat for more than 15 min;
wherein the staged heat treatment comprises:
the first heat treatment stage comprises the steps of carrying out heat preservation treatment on the liquid mixture at a first temperature to obtain a heat preservation treated object, wherein the first temperature is 800-1300 ℃, and the heat preservation treatment time is more than 24 hours;
the second heat treatment stage comprises the step of cooling the heat preservation treatment object to obtain a blocky desulfurizing agent for the RH furnace;
the step-by-step cooling treatment is carried out on the heat preservation treatment object, and the step-by-step cooling treatment comprises the following steps:
the first cooling treatment step comprises the step of cooling the heat-preserving treatment object at a first cooling rate in a second temperature interval to obtain a first cooling treatment object, wherein the second temperature interval is 500-800 ℃, and the first cooling rate is more than 150 ℃/h;
a second cooling treatment step, which comprises cooling the first cooling treatment object at a second cooling rate in a third temperature interval to obtain a second cooling treatment object, wherein the third temperature interval is 300-500 ℃, and the second cooling rate is more than 80 ℃/h;
and a third cooling treatment step, wherein the second cooling treatment object is cooled at a third cooling rate in a fourth temperature interval to obtain the block-shaped desulfurizing agent for the RH furnace, the fourth temperature interval is 25-300 ℃, and the third cooling rate is more than 40 ℃/h.
2. The desulfurizing agent for RH furnace according to claim 1, wherein the desulfurizing agent for RH furnace satisfies at least one of the following conditions:
(1) In the desulfurizing agent for RH furnace, the content of 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is 30% -80%;
(2) The average particle size of the desulfurizing agent for the RH furnace is 3-50 mm.
3. The preparation method of the desulfurizing agent for the RH furnace is characterized by comprising the following steps:
providing a reaction raw material, wherein the reaction raw material comprises mixed powder of lime powder, fluorite powder and alumina powder;
carrying out melting treatment on the reaction raw materials to obtain a liquid mixture;
the liquid mixture is crushed after being subjected to sectional heat treatment to obtain the desulfurizing agent for the RH furnace,
wherein the desulfurizing agent for RH furnace comprises 12 CaO.7Al 2 O 3 Phase and 11 CaO.7Al 2 O 3 ·CaF 2 In the RH furnace desulfurizing agent, the phase is 12 CaO.7Al 2 O 3 Phase and the 11 CaO.7Al 2 O 3 ·CaF 2 The sum of the mass percentages of the phases is more than 30%, and the desulfurizing agent for the RH furnace comprises the following components in percentage by mass: caO,35% -50%; caF (CaF) 2 ，5%~35%；Al 2 O 3 ，20%~38%；SiO 2 ，1%~8%；MgO≤8%；TiO 2 ≤0.1%；C≤0.15%；S≤0.1%；
Wherein the melting treatment of the reaction raw materials comprises the following steps:
smelting the reaction raw materials to obtain a smelting mixture;
heating the smelting mixture to 1400-1550 ℃ and then preserving heat for more than 15 min;
wherein the staged heat treatment comprises:
the first heat treatment stage comprises the steps of carrying out heat preservation treatment on the liquid mixture at a first temperature to obtain a heat preservation treated object, wherein the first temperature is 800-1300 ℃, and the heat preservation treatment time is more than 24 hours;
the second heat treatment stage comprises the step of cooling the heat preservation treatment object to obtain a blocky desulfurizing agent for the RH furnace;
the step-by-step cooling treatment is carried out on the heat preservation treatment object, and the step-by-step cooling treatment comprises the following steps:
the first cooling treatment step comprises the step of cooling the heat-preserving treatment object at a first cooling rate in a second temperature interval to obtain a first cooling treatment object, wherein the second temperature interval is 500-800 ℃, and the first cooling rate is more than 150 ℃/h;
a second cooling treatment step, which comprises cooling the first cooling treatment object at a second cooling rate in a third temperature interval to obtain a second cooling treatment object, wherein the third temperature interval is 300-500 ℃, and the second cooling rate is more than 80 ℃/h;
and a third cooling treatment step, wherein the second cooling treatment object is cooled at a third cooling rate in a fourth temperature interval to obtain the block-shaped desulfurizing agent for the RH furnace, the fourth temperature interval is 25-300 ℃, and the third cooling rate is more than 40 ℃/h.
4. The preparation method of claim 3, wherein the heat preservation treatment time is 24-30 hours.
5. A production method according to claim 3, wherein the production method satisfies at least one of the following conditions:
(1) The first cooling rate is 150-250 ℃/h;
(2) The second cooling rate is 80-180 ℃/h;
(3) The third cooling rate is 40-70 ℃/h.
6. The method according to any one of claims 3 to 5, wherein the average particle diameter of the mixed powder is 0.075mm to 0.300mm.
7. The method according to any one of claims 3 to 5, wherein the temperature of the smelting mixture is raised to 1400 ℃ to 1550 ℃ and then kept for 15min to 30min.
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| JP2003328022A (en) * | 2002-05-16 | 2003-11-19 | Nippon Magnetic Dressing Co Ltd | Desulfurizing agent for molten steel and manufacturing method therefor |
| CN102876842A (en) * | 2012-06-28 | 2013-01-16 | 辽宁天和科技股份有限公司 | Premelting slugging desulfurizer taking 12 CaO*7Al2O3 and 3CaO*5Al2O3 as main phases |
| CN106498125A (en) * | 2017-01-16 | 2017-03-15 | 河南省西保冶材集团有限公司 | A kind of RH stoves desulfurizing agent |
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| JP2003328022A (en) * | 2002-05-16 | 2003-11-19 | Nippon Magnetic Dressing Co Ltd | Desulfurizing agent for molten steel and manufacturing method therefor |
| CN102876842A (en) * | 2012-06-28 | 2013-01-16 | 辽宁天和科技股份有限公司 | Premelting slugging desulfurizer taking 12 CaO*7Al2O3 and 3CaO*5Al2O3 as main phases |
| CN106498125A (en) * | 2017-01-16 | 2017-03-15 | 河南省西保冶材集团有限公司 | A kind of RH stoves desulfurizing agent |
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