CN113462840B - Comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag - Google Patents
Comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B11/00—Making pig-iron other than in blast furnaces
- C21B11/10—Making pig-iron other than in blast furnaces in electric furnaces
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- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
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- C—CHEMISTRY; METALLURGY
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- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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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
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
- C21C1/025—Agents used for dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
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- 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
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- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/40—Gas purification of exhaust gases to be recirculated or used in other metallurgical processes
- C21B2100/44—Removing particles, e.g. by scrubbing, dedusting
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
- C21B2100/66—Heat exchange
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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
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- C21C2005/363—Slag cements
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- 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
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Abstract
The invention discloses a comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag, which comprises the following steps: reducing and smelting the liquid converter slag, the hot desulfurization slag, the carbonaceous reducing agent and the silicon-containing raw material to obtain reduced molten iron and reduced slag with the Tfe content of less than or equal to 4% and the alkalinity of 1.2 +/-0.2; in the reduction smelting, the initial temperature is more than or equal to 1000 ℃, and the temperature is increased to the end temperature of 1530 +/-10 ℃ at the speed of 4-5 ℃/min; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): (17-23); recovering the generated heat and the coal gas to obtain qualified coal gas; water quenching the reducing slag to form water slag; smelting the reduced molten iron by a dephosphorization converter after dephosphorization to obtain dephosphorized molten steel and dephosphorized slag; and (3) stewing the dephosphorization residues, magnetically separating, crushing and screening to obtain dephosphorization tailings and slag steel. The method solves the problem of comprehensive utilization of iron, heat and slag of converter steel slag and desulfurized slag.
Description
Technical Field
The invention relates to the technical field of steel making, in particular to a comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag.
Background
As the "environmental protection tax Act" was implemented from 2018, 1 month and 1 day, the metallurgical slag began to collect environmental protection taxes (25 Yuan/t). The metallurgical slag mainly comprises blast furnace slag and converter slag (steel slag): the blast furnace granulated slag has better gelatinization property after being finely ground, can be doped into cement in a larger proportion (40 percent), and basically realizes resource utilization; however, the converter slag and the desulfurized slag have relatively complex characteristics, and the high value-added resource utilization rate is always low. Converter slag is a dephosphorization byproduct in steel making, basically, the separation of metallic iron and slag is carried out by water pumping, temperature reduction (heat waste at 1300 ℃), crushing and magnetic separation, and FeO (23%) in the steel slag also enters tailings due to non-magnetism. The slag steel selected by magnetism replaces scrap steel with low proportion due to low purity, and the tailings are not easy to be finely ground due to high hardness. Partial tailings enter sintering ingredients, but the phosphorus content of molten iron is easily increased greatly, so that most of tailings can be used as road base materials only after being aged, and the problem which needs to be solved at present is solved urgently.
The converter steel slag heat energy utilization difficulty is that because the steel slag has small heat conductivity coefficient, the main rock phase structure of the steel slag belongs to silicate phase, and the silicate slag has the following characteristics: (1) Low thermal conductivity, a liquid phase fraction of 1400 to 1500 ℃ of about 0.1 to 0.3W/(m.K), a glass phase fraction of 1 to 2W/(m.K), a crystal phase fraction of about 7W/(m.K), and an average thermal conductivity of only 0.4W/(m.K). (2) The viscosity of the steel slag is sharply increased along with the reduction of the temperature, the pretreatment process of the steel slag is closely related to the crystallization process of the steel slag, and the process parameters for treating various slag are greatly fluctuated in the treatment process of the steel slag. (3) The enthalpy of the slag is large, the heat content in the steel slag greatly fluctuates along with the temperature change of the slag, and the heat conductivity is low, the heat exchange is slow, and the heat exchange medium is difficult to select. (4) The liquid steel slag of the converter is treated by a water quenching process, and f-CaO contained in high-temperature steam seriously damages equipment for recovering heat energy.
The desulfurization slag is a byproduct of steel-making desulfurization, and basically is separated from the slag by water cooling (heat energy of 1200 ℃ is wasted) of a single braising tank, crushing and magnetic separation because the sulfur content is high. The magnetically separated slag iron has high sulfur content, so the steel-making recycling proportion is low, and the tailings have high sulfur content and are not easy to utilize.
How to develop a method for comprehensively treating converter steel slag and desulfurization slag solves the problem of comprehensive utilization of iron, heat and slag of converter steel slag and desulfurization slag in steel mills, and becomes a key problem for research of metallurgical workers.
Disclosure of Invention
The invention aims to provide a comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag, which solves the problem of comprehensive utilization of iron, heat and slag of converter slag and desulfurized slag in steel mills, has high recovery rate of metal iron in slag (50 percent higher than the slag stewing process) and high added value of tailings, and can mix the produced water slag into cement after deep processing and fine grinding; the latent heat of the converter slag and the desulphurization slag is fully utilized.
In order to achieve the above objects, the present invention provides a method for comprehensive utilization of iron, heat and slag of converter slag and desulfurized slag, the method comprising:
reducing and smelting the liquid converter slag, the hot desulfurization slag, the carbonaceous reducing agent and the silicon-containing raw material to obtain reduced molten iron and reduced slag with the Tfe content of less than or equal to 4% and the alkalinity of 1.2 +/-0.2; wherein the temperature is raised to the end point temperature of 1530 +/-10 ℃ at the speed of 4-5 ℃/min at the initial temperature of more than or equal to 1000 ℃ in the reduction smelting; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): (17-23);
comprehensively recycling the coal gas and heat generated in the reduction smelting to obtain qualified coal gas and qualified steam;
water quenching is carried out on the reducing slag to form water granulated slag, and the water granulated slag is dried by utilizing the generated steam to obtain dry slag;
adding a recarburizer into the reduced molten iron for recarburization to obtain recarburized molten iron, and then carrying out powder injection dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron oxide scale to obtain dephosphorized molten iron;
the dephosphorized molten iron is supplied to a converter for smelting to obtain dephosphorized slag;
and carrying out slag stewing treatment on the dephosphorized slag, and then carrying out magnetic separation, crushing and screening to obtain dephosphorized tailings for preparing road base materials and slag steel for replacing scrap steel in a steel plant.
Further, the reduction smelting of the liquid converter slag, the thermal desulfurization slag, the carbonaceous reducing agent and the silicon-containing raw material specifically comprises the following steps:
and (3) pouring the liquid converter slag and the desulfurized slag into a slag ladle, hoisting the slag ladle to an electric furnace, and adding a carbonaceous reducing agent and a silicon-containing raw material for reduction smelting.
Further, bottom blowing N in the reduction smelting 2 To effect agitation.
Further, the carbonaceous reducing agent comprises at least one of coke powder and anthracite; the siliceous feedstock comprises at least one of silica, bauxite, and iron-containing tailings.
Further, the time of the reduction smelting is 100-150min.
Further, the ratio of the total mass of the liquid converter slag and the hot desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100:10:20.
and further, stopping the reduction smelting when the Tfe content in the reduction slag is not more than 4% and the alkalinity is 1.2 +/-0.2, carrying out slag tapping operation, monitoring during slag tapping, quickly closing a slag outlet by using a sliding plate slag stopping mechanism when liquid molten iron appears in monitoring, and meanwhile, arranging a slag-iron separation dam in a slag tapping channel.
Further, when the recarburizing agent is added into the reduced molten iron for recarburization, the recarburizing agent is added into the two bags of reduced molten iron after the two bags of reduced molten iron are uniformly mixed for recarburization.
Further, the comprehensive recycling of the coal gas and heat generated during the reduction smelting to obtain qualified coal gas and qualified steam for a pipe network comprises the following steps:
firstly, reducing the temperature of the flue gas from 1400 +/-20 ℃ to 800 +/-20 ℃ by utilizing vaporization cooling, and leading the generated supersaturated steam to flow into a steam pipe network after passing through a heat accumulator;
then water mist is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 800 +/-20 ℃ to less than or equal to 200 ℃, after fine dedusting is carried out by a high-temperature dedusting cloth bag, water is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 150 +/-20 ℃ to less than 70 ℃, and clean coal gas with the CO of the coal gas being more than or equal to 30% is obtained and is merged into a coal gas pipe network.
Further, the method comprises the following steps of carrying out powder injection dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron scale to obtain dephosphorized molten iron and dephosphorized slag:
carrying out first top powder spraying dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron scale to obtain dephosphorization water with the P content less than 0.30%;
and carrying out secondary top powder spraying dephosphorization on the dephosphorized water with the P content of less than 0.30% by adopting passivated lime powder, oxygen and iron oxide scale to obtain the dephosphorized molten iron with the P content of less than 0.080%.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the invention provides a comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag, which comprises the steps of carrying out reduction smelting on liquid converter slag obtained by converter smelting, the hot desulfurized slag, a carbonaceous reducing agent and a silicon-containing raw material, stopping smelting when the Tfe content in the slag is reduced to be below 4 percent and the alkalinity is 1.2 +/-0.2, and carrying out slag tapping operation when the slag and the iron are well separated to obtain reduced molten iron and reduced slag with the Tfe content of not more than 4 percent and the alkalinity of 1.2 +/-0.2; wherein, the temperature is increased to the end point temperature of 1530 +/-10 ℃ at the speed of 4-5 ℃/min at the initial temperature of more than or equal to 1000 ℃ in the reduction smelting; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): (17-23);
comprehensively recycling the coal gas and heat generated in the reduction smelting process to obtain clean coal gas and steam, and merging the clean coal gas and the clean steam into a coal gas pipe network and a steam pipe network;
water quenching is carried out on the reducing slag to form water granulated slag, the generated steam is utilized to dry the water granulated slag to obtain dry slag, and the dry slag can be doped into cement after deep processing and fine grinding;
adding a recarburizer into the reduced molten iron for recarburization, and then carrying out top powder injection dephosphorization by adopting passivated lime powder, oxygen and iron scale to obtain dephosphorized molten iron; the dephosphorized molten iron is supplied to a converter for smelting to obtain dephosphorized slag; and pouring the dephosphorized slag into a slag stewing pit for slag stewing treatment, and then carrying out magnetic separation, crushing and screening to obtain dephosphorized tailings for preparing road base materials and slag steel for replacing scrap steel in a steel plant.
Therefore, comprehensive utilization of iron, heat and slag is realized, the recovery rate of the slag metallic iron is high (50% higher than that of the slag stewing process), fe and FeO in the steel slag are fully reduced into high-temperature metallic molten iron by the process, the steel making recycling is more economical, and the recycling amount of steel making waste steel can be increased; the added value of the tailings is high, and the produced granulated slag can be doped into cement after deep processing and fine grinding; the latent heat of the converter slag and the desulphurization slag is fully utilized; the enrichment of phosphorus and sulfur in the main process of steel and iron can be reduced, the phosphorus content of molten iron is reduced, and the high sulfur caused by the recollecting of slag iron in steel making is reduced; the method has the advantages of small occupied area, environment-friendly working environment and contribution to improving the production efficiency.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart showing a method for the comprehensive utilization of iron, heat and slag of converter slag and desulfurized slag according to the present invention;
FIG. 2 is a schematic flow chart of a method for the comprehensive utilization of iron, heat and slag from converter slag and desulfurized slag according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are illustrative of the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood in accordance with the meanings commonly used in the art. Accordingly, 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 invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods. The terms "first", "second", and the like used in the present invention do not denote order, and may be understood as nouns.
The method for utilizing heat energy of converter steel slag in the prior art generally comprises the following steps:
the heat energy of the steel slag is utilized for modifying the steel slag. The method is characterized in that other smelting slag which is produced by a steel mill and can not be used for hot disintegrating slag treatment is added into the steel slag of the high-temperature liquid converter, and the heat energy of the steel slag is utilized to promote the modification reaction of the steel slag. The modification reaction mainly comprises the desulfurization slag of a converter, the gas ash of a blast furnace, and the acid-containing mud and the oil-containing iron oxide mud of steel rolling. Adding the part of smelting slag into liquid oxidized steel slag of a converter, utilizing reaction heat absorption to rapidly cool the liquid steel slag of the converter to about 1400 ℃, utilizing heat energy to heat the smelting slag which can not be subjected to hot slag disintegrating treatment to a temperature which can be implemented by the hot slag disintegrating process, utilizing reducing substances in the smelting slag to reduce oxides in the liquid steel slag of the converter, transferring the heat energy to chemical energy of the reaction, then using the steel slag which is in a nearly solid state for hot slag disintegrating treatment, and further recycling in the subsequent process link. The technological method for modifying the steel slag is one of effective methods for stably recovering the heat energy of the steel slag at the liquid high-temperature stage.
The technological process is mainly carried out in a slag tank, so the chemical heat in the reaction process is basically provided by liquid steel slag, wherein the main equation of the desulfurization slag modification reaction is as follows:
3(Fe、Mn)O+2Al＝3Fe/Mn+Al 2 O 3 +Q (1)
Si+2FeO＝2Fe+SiO 2 -Q (2)
Mn+FeO＝Fe+MnO-Q (3)
C+2FeO＝2Fe+CO 2 -Q (4)
2P+5FeO＝5Fe+P 2 O 5 -Q (5)
al in the formula (1) is derived from high-aluminum slag powder which is not completely reacted in the KR desulfurized slag, and Si, mn, C, P and the like in the reaction of the formulas (2) to (5) are derived from molten iron or iron beads which enter a slag pot in the slag skimming process of the desulfurized slag.
Oxide SiO after finishing modification reaction 2 、MnO、Al 2 O 3 And the like, and under the condition of proper temperature, the slag forming reaction with f-CaO and f-MgO in the slag is possible, which is beneficial to improving the stability of the steel slag after treatment. The heat energy required by the slagging reaction still comes from the sensible heat of the steel slag, and the slagging reaction of the steel slag mainly adopts the following formula:
SiO 2 +2f-CaO→C 2 S-Q
SiO 2 +3f-CaO→C 3 S-Q
Al 2 O 3 +f-CaO→CmAn-Q
f-CaO+SiO 2 +2f-MgO→CMS-Q
however, this method has disadvantages:
(1) The method does not effectively utilize the sensible heat recovery of the steel slag;
(2) Due to the desulfurization slag and the gas ash of a blast furnace, after the acid-containing dust mud and the oil-containing iron oxide mud of steel rolling are added into the liquid steel oxide slag of the converter, the temperature of the steel slag is obviously reduced to be below 1400 ℃, the liquid steel slag begins to separate out a solid phase, the smooth proceeding of the above reaction is seriously influenced, and the reaction is not sufficient.
(3) When the reaction is carried out in a slag pot, a large amount of smoke and dust can be generated to cause environmental pollution, and splashing can be caused when the reaction is serious.
(4) The modified steel slag still cannot be utilized with high added value.
In conclusion, the above method cannot realize comprehensive utilization of iron, heat and slag.
The technical scheme of this application embodiment for solving can't realize iron, heat and sediment comprehensive utilization technical problem among the prior art, the general thinking is according to following:
according to an exemplary embodiment of the present invention, there is provided a method for recycling iron, heat and slag of converter slag and desulfurized slag, as shown in fig. 1, comprising:
s1, carrying out reduction smelting on the liquid converter slag, the thermal desulfurization slag, a carbonaceous reducing agent and a silicon-containing raw material to obtain reduced molten iron and reduced slag with the Tfe content of less than or equal to 4% and the alkalinity of 1.2 +/-0.2; wherein, the temperature is increased to the end point temperature of 1530 +/-10 ℃ at the speed of 4-5 ℃/min at the initial temperature of more than or equal to 1000 ℃ in the reduction smelting; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): (17-23);
the principle and the function of the reduction smelting are as follows:
①FeO+C＝Fe+CO↑；
(2) FeS + CaO (steel slag) + C = CaS + Fe + CO ≠ C;
③2Ca 3 (P 2 O 4 ) 2 +6SiO 2 +10C+2xFe＝(1-x/4)P 4 ↑+6CaSiO 3 +xFe 2 P+10CO↑；
the reaction (1) is a main reaction, and FeO in the steel slag is reduced into liquid metal iron; in the embodiment of the invention, feO in the steel slag is reduced sufficiently, an ore phase similar to that of blast furnace slag can be obtained by adding siliceous material for adjustment, and water granulated slag rich in melilite and dicalcium silicate is formed after water quenching, so that the steel slag has potential gelling property;
the reaction (2) reacts FeS in the desulfurized slag iron into CaS by utilizing CaO in the steel slag, and the CaS enters the slag;
the Ca in the steel slag is obtained by the reaction (3) 3 (P 2 O 4 ) 2 The reaction is two P elements, one is P 4 One of them is Fe 2 P enters the molten iron.
In the embodiment of the invention, the carbonaceous reducing agent is added to reduce and precipitate the iron to the bottom of the ladle, so that serious explosion accidents caused by mixing iron beads in the slag and water quenching are avoided, and then the slag is modified according to the standard FeO of the slag of less than 3 percent, so that the slag is completely modified.
The ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): reasons for (17-23): if the carbonaceous reducing agent is added too much, the cost of the reducing agent is increased, and if the carbonaceous reducing agent is added too little, the adverse effects that FeO in the steel slag is reduced incompletely and the carbon content in the molten iron is low are easily caused; if the silicon-containing raw material is excessively added, the adverse effects of increasing the cost of the silicon-containing raw material and reducing the potential gelation property of the water-quenched slag are easily caused, and if the silicon-containing raw material is excessively added, the adverse effects that CaO and MgO in the slag cannot be fully melted at the smelting temperature to form compounds are easily caused; preferably, the ratio of the total mass of the liquid converter slag and the hot desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100:10:20.
the proportion of the liquid converter slag and the thermal desulfurization slag is based on the proportion of the desulfurization slag and the converter slag generated in the same furnace in a steel plant; and the adjustment range can be adjusted properly, and the adjustment range can be specifically within the range of the desulfurized slag generated by 1 to 3 heats and the converter slag generated by 1 to 3 heats.
When the Tfe content in the slag is reduced to below 4 percent, the alkalinity is 1.2 +/-0.2, and when the slag and the iron are well separated, the smelting is stopped, and the slag tapping operation is carried out: by adding siliceous material for regulation, an ore phase similar to that of blast furnace slag can be obtained, and water granulated slag rich in melilite and dicalcium silicate is formed after water quenching, so that the slag has potential gelling property;
alkalinity R = CaO/SiO 2 If the alkalinity is less than 1, the adverse effects of increasing the cost of the silicon-containing raw material and reducing the potential gelation property of the water-quenched slag are caused; if the alkalinity is more than 1.4, the adverse effect that CaO and MgO in the slag can not be fully melted to form compounds at the smelting temperature is caused;
the Tfe content is more than 4 percent, and the adverse effect of incomplete reduction of FeO in the steel slag exists;
the temperature of the reduction smelting is 1530 +/-10 ℃, and if the reaction temperature is lower than 1520 ℃, the later-stage dephosphorization of the reduced iron is easy to cause; if the reaction temperature is higher than 1540 ℃, the consumption of energy media and refractory materials is easily increased;
the reason why the temperature is raised to the end point temperature of 1530 +/-10 ℃ at the speed of 4-5 ℃/min at the initial temperature of more than or equal to 1000 ℃ in the reduction smelting is as follows: if the initial temperature is lower than 990 ℃, the temperature rise time is long, and the power consumption is large; if the end point temperature is lower than 1520 ℃, the later-stage reduced iron can not be dephosphorized normally; if the end point temperature is more than 1540 ℃, the consumption of energy media and refractory materials is easily increased; the speed of 4-5 ℃/min can ensure that the process from the initial temperature to the end temperature is finished within a certain time, the speed is too low, the duration is too long, the smelting efficiency and the treatment capacity are not favorably improved, the speed is too high, the duration is too short, the equipment investment cost and the energy medium consumption are not favorably reduced; and the temperature is raised to 1530 +/-10 ℃ at the speed of 4-5 ℃/min, so that the slag can be more thoroughly modified.
Preferably, in the step S1,
the time of the reduction smelting is 100-150min. The adverse effect that the temperature of the reducing slag and the reducing iron does not meet the requirement is caused when the time is too short; the long time has the adverse effects that the energy medium consumption is increased, the treatment capacity and the slag quantity cannot reach the balance with the slag quantity generated by a steel mill;
bottom blowing N in reduction smelting 2 To effect agitation. Is beneficial to uniform mixing so as to accelerate the reaction;
the carbonaceous reducing agent includes at least one of coke powder and anthracite. Preferably, the mass fraction of carbon of the coke powder and/or anthracite satisfies: c is more than or equal to 82 percent, and the particle size of the coke powder and/or the anthracite is 10-25mm;
the siliceous material includes at least one of silica and iron-containing tailings. Preferably, the mass fraction of silica in the silica and/or iron-containing tailings satisfies: siO 2 2 ≥96％。
Specifically, the step S1 includes:
s101, obtaining liquid converter slag through converter smelting;
in the step S1, after the smelting of the converter is finished, liquid converter slag is poured into a slag pot, then steel is tapped, slag splashing furnace protection operation is carried out after the steel is tapped, and slag pouring operation is not carried out after slag splashing;
the slag splashing furnace protection is that the residual slag after the components are adjusted is splashed on the surface of a furnace lining by utilizing high-speed nitrogen to form a slag splashing layer. The slag splashing layer solidifies the decarburized layer on the surface layer of the magnesia carbon brick, inhibits the oxidation of the surface layer of the furnace lining and lightens the scouring erosion of high-temperature furnace slag on the surface of the brick.
S102, obtaining thermal desulfurization slag;
collecting hot desulfurization slag generated by performing molten iron pretreatment on KR desulfurization;
adopt the KR desulfurization to carry out the molten iron preliminary treatment usually among the prior art, the KR desulfurization technique is for refractory material's agitator immerses hot metal jar internal rotation stirring molten iron, makes the molten iron produce the swirl, adds the desulfurizer simultaneously and makes it be drawn into inside the molten iron and fully reflects, has good dynamics condition, and desulfurization efficiency is high, can realize dark desulfurization.
S103, reduction smelting; the method specifically comprises the following steps:
pouring high-temperature thermal-state converter slag into a special slag ladle (built by magnesia carbon bricks), then pouring thermal-state desulfurized slag into the slag ladle, (pouring the converter slag into the slag ladle firstly, then pouring the desulfurized slag into the slag ladle), then hoisting the slag ladle to a position below an electric furnace with a rotatable ladle cover (similar to the electric furnace of an LF furnace) for reduction smelting, and meanwhile, hoisting the slag ladle to a position below the electric furnace with a rotatable ladle cover for reduction smeltingAdding 7-13% of carbonaceous reducing agent and 17-23% of silicon-containing raw material, introducing N into bottom portion 2 Stirring, and carrying out heating, modifying and reducing operation on the converter slag and the desulfurized slag, wherein the initial temperature is about 1000 ℃, and the final temperature is 1530 +/-10 ℃.
In order to avoid explosion during slag flushing, monitoring is carried out during slag discharging, a slag outlet is quickly closed by using a sliding plate slag stopping mechanism when liquid molten iron is monitored, and a slag and iron separation dam is arranged on a slag discharging channel.
S2, comprehensively recycling the coal gas and heat generated in the reduction smelting process to obtain qualified coal gas and steam;
the step S2 specifically includes:
firstly, the temperature of the flue gas is reduced from 1400 +/-20 ℃ to 800 +/-20 ℃ by utilizing vaporization cooling, and the generated supersaturated steam is merged into a steam pipe network after passing through a heat accumulator;
then water mist is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 800 +/-20 ℃ to 200 ℃ -150 ℃, after fine dedusting by a high-temperature dedusting cloth bag, water is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 150 +/-20 ℃ to less than 70 ℃, and clean coal gas with the CO of the coal gas being more than or equal to 30% is obtained and is merged into a coal gas pipe network.
The reasons or advantages of gradually cooling for multiple times in the steps are as follows:
the higher the flue gas temperature, the lower the cost of manufacturing the evaporation cooled flue and vice versa.
However, when the temperature of the flue gas is lower than 800 ℃ +/-20 ℃, the recovered gas causes gas explosion due to sparks in smoke dust, so when the temperature of the flue gas is lower than 800 ℃ +/-20 ℃, the temperature of the flue gas is rapidly reduced to 200-150 ℃ by adopting water mist spraying, but when the temperature of water vapor is lower than 100 ℃, water is condensed to be attached to a cloth bag to cause the cloth bag of the dust removal to be hardened, so the temperature of the flue gas is controlled to be 200-150 ℃ before the flue gas enters a dust remover, and after the flue gas enters the dust remover, the temperature of related equipment of the gas holder cannot exceed 70 ℃, so that the temperature of the flue gas needs to be further washed and reduced to be lower than 70 ℃.
In the embodiment 1 of the invention, 80% of heat generated by slag reduction smelting is converted into supersaturated steam, the generated steam amount is 240kg/t slag, the baking heat of the granulated slag is utilized by 80%, and the consumed steam amount is estimated to be 130kg/t slag.
S3, water quenching is carried out on the reducing slag to form water slag, and steam generated by the water quenching is used for drying the water slag to obtain dry slag;
the dry slag generated in the step S3 can be doped into cement after deep processing and fine grinding, and the added value is high.
S4, adding a recarburizer into the reduced molten iron for recarburization to obtain recarburized molten iron, and then carrying out top powder injection dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron oxide scale to obtain dephosphorized molten iron;
in the step S4, dephosphorization by top injection may be specifically performed for 2 times, or may be performed for multiple times in other embodiments.
In the embodiment of the present invention, the step S4 specifically includes:
carrying out first top powder spraying dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron scale to obtain dephosphorization water with the P content less than 0.30%;
and carrying out secondary top powder spraying dephosphorization on the dephosphorized water with the P content of less than 0.30% by adopting passivated lime powder, oxygen and iron oxide scale to obtain the dephosphorized molten iron with the P content of less than 0.080%.
The recarburizer may be specifically a small coke (particle size 5-10 mm).
Adding a certain carburant to meet the requirement of subsequent dephosphorization, wherein the requirement of subsequent dephosphorization is specifically that C is more than or equal to 1 percent, si is less than or equal to 0.1, P is less than or equal to 2, S is less than or equal to 0.050, and the temperature is more than or equal to 1400 ℃; the amount of the carburant added specifically meets the requirement of subsequent dephosphorization.
If the recarburizer is not added and passivated lime powder, oxygen and iron scale are directly adopted, the loss of carbon in the dephosphorized iron is serious, and the liquid dephosphorized iron is solidified when a liquid phase line of the dephosphorized iron is raised;
s5, supplying the dephosphorized molten iron to a converter for smelting to obtain dephosphorized slag;
specifically, the generated dephosphorized molten iron is poured into an iron ladle of a steel plant to replace partial molten iron (or cast into iron blocks to replace scrap steel) for converter smelting;
s6, pouring the dephosphorized slag into a slag stewing pit for slag stewing treatment, and then carrying out magnetic separation, crushing and screening to obtain dephosphorized tailings for preparing road base materials and slag steel for replacing scrap steel in a steel plant.
The step S6 specifically includes:
the dephosphorization slag generated by molten iron dephosphorization is poured into a slag pot from a slag ladle, then the dephosphorization slag is poured into a slag stewing pit by using a crown block, the slag stewing treatment is carried out by using the wastewater generated in the purification of washing gas water, the dephosphorization slag after slag stewing is subjected to magnetic separation, crushing and screening, the slag steel magnetically separated out is used for a steel mill to replace scrap steel, and the generated dephosphorization tailings are used as a road base material.
The invention creatively develops a method for comprehensively treating converter steel slag and desulfurization slag, solves the problem of comprehensive utilization of iron, heat and slag of converter steel slag and desulfurization slag in steel plants, has high recovery rate of metal iron in the slag (50 percent higher than that of a slag stewing process), fully reduces Fe and FeO in the steel slag into high-temperature metal molten iron, is more economical for recycling steel making, and can increase the recycling amount of steel-making waste steel; the added value of the tailings is high, and the produced granulated slag can be doped into cement after deep processing and fine grinding; the latent heat of the converter slag and the desulphurization slag is fully utilized; the enrichment of phosphorus and sulfur in the main process of steel and iron can be reduced, the phosphorus content of molten iron is reduced, and the high sulfur caused by the recollecting of slag iron in steel making is reduced; the process has the advantages of small occupied area, environment-friendly working environment and contribution to improving the production efficiency.
Hereinafter, a method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag according to the present application will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
1. After the smelting end point of the converter, pouring the high-temperature thermal-state steel slag into a slag pot, then tapping, performing slag splashing furnace protection operation after tapping, and not performing slag pouring operation after slag splashing;
2. pouring high-temperature thermal-state converter slag into a special slag ladle (built by magnesia carbon bricks), then pouring thermal-state desulphurization slag into the slag ladle, (basically three-furnace liquid-state converter slag and three-furnace molten iron desulphurization slag, pouring the converter slag into the slag ladle, then pouring the desulphurization slag into the slag ladle), then hanging the slag ladle under a rotary electric furnace with a rotatable ladle cover (similar to an electric furnace of an LF furnace) for reduction smelting, and simultaneously adding 10 percent of slagCarbonaceous reducing agent (coke powder, anthracite, etc.) and 20% silica (or silica, tailings containing iron, etc.), and N is introduced into the bottom of the mixture 2 Stirring, and carrying out heating modification reduction operation on the converter slag and the desulfurized slag, wherein the initial temperature is 1000 ℃, the end temperature is 1540 ℃, and the smelting period is about 120 min;
in the present embodiment, the components of the thermal desulfurization slag are shown in table 1, and the components of the liquid steel slag are shown in table 2, in other embodiments, the thermal desulfurization slag and the liquid steel slag may be other components.
TABLE 1
| Thermal desulfurization slag | CaO％ | SiO 2 ％ | MgO％ | S％ | FeO％ | TFe％ | Al 2 O 3 ％ | R | Temperature of |
| Composition of | ≥30 | ≤20 | ≥0.5 | ≥8 | ≥8 | ≥3 | ≥1300 | ||
| Target value | 35 | 12 | 15 | 1 | 10 | 14 | 6 | 3.0 | 1300 |
TABLE 2
| Liquid steel slag | CaO | SiO 2 | MgO | P 2 O 5 | FeO (gao) | Metallic Fe | TFe | Al 2 O 3 | R | Temperature of |
| Composition of | ≥45 | ≤20 | 8～12 | ≥1 | ≥15 | ≥8 | ≥3 | ≥1300 | ||
| Target value | 48 | 15 | 9 | 1.5 | 23 | 10 | 28 | 3 | 3.2 | 1300 |
3. When the Tfe content in the slag is reduced to below 4%, the alkalinity is 1.2 at the same time, the slag and iron are stopped from smelting when being well separated, the slag tapping operation is carried out, an infrared camera is utilized to monitor during slag tapping, a sliding plate slag stopping mechanism is utilized to quickly close a slag outlet when liquid molten iron is monitored, and a slag and iron separating dam is arranged in a slag tapping channel to avoid explosion during slag flushing. The reducing slag comprises the following components:
TABLE 3
| Slag of mine | CaO | SiO 2 | MgO | Al 2 O 3 | P 2 O 5 | MnO | S | FeO | TFe | R |
| Standard of merit | ～50 | ～40 | 8～12 | ～5 | ≤1 | ≤2 | ≤2 | ≤5 | ≤4 | 1.1～1.3 |
| Target value | 45 | 37 | 10 | 4 | 0.5 | 0.5 | 1 | 3 | 2.3 | 1.2 |
4. The method comprises the steps of comprehensively recycling coal gas and heat generated during smelting, firstly reducing the temperature of flue gas from about 1400 ℃ to 800 ℃ by utilizing vaporization cooling (the generated supersaturated steam is merged into a steam pipe network after passing through a heat accumulator), then adopting water mist to spray, remove dust and reduce the temperature, reducing the temperature of the flue gas from 800 ℃ to less than or equal to 200 ℃, carrying out fine dust removal on the flue gas by using a high-temperature dust removal cloth bag, then adopting water to spray, remove dust and reduce the temperature, reducing the temperature of the flue gas from about 150 ℃ to less than 70 ℃, and obtaining clean coal gas with the CO of the coal gas being more than or equal to 30% and merging the clean coal gas into the coal gas pipe network.
5. Water quenching is carried out on the generated reducing slag to form water slag, and the water slag can be dried by utilizing the generated steam when being finely ground and dried;
6. the produced reduced iron is subjected to ladle pouring treatment (the two-in-one is that the molten iron is poured into a ladle), and meanwhile, a certain carburant is added to meet the requirement of subsequent dephosphorization, and the conditions of the reduced iron are as follows:
TABLE 4
| Reduced iron | C％ | Si％ | P％ | S％ | Temperature of |
| Standard of merit | ≥1 | ≤0.1 | ≤2 | ≤0.050 | ≥1400 |
| Target value | 1.2 | 0.05 | 1.6 | 0.02 | 1500 |
7. Hoisting reduced iron to a refining position, carrying out top powder injection dephosphorization by adopting passivated lime powder, oxygen and iron oxide scale, reducing the P content in molten iron to be less than or equal to 0.080% by two-step dephosphorization (reducing the phosphorus in the molten iron to be about 0.30% in the first step, and reducing the phosphorus in the molten iron to be less than 0.080% in the second step), pouring the generated dephosphorized molten iron into an iron ladle of a steel plant to replace partial molten iron (or casting iron blocks to replace scrap steel), wherein the dephosphorized iron condition is as follows (the smelting period is about 40 min): adding zinc-containing waste steel into molten iron to carry out dephosphorization converter smelting to obtain dephosphorized iron;
TABLE 5
| Dephosphorized iron | C％ | Si％ | P％ | S％ | Temperature of |
| Standard of merit | ≥0.8 | ≤0.1 | ≤0.15 | ≤0.050 | ≥1450 |
| Target value | 1 | 0.01 | 0.080 | 0.020 | 1480 |
8. The dephosphorization slag generated by molten iron dephosphorization is poured into a slag tank from a slag ladle, then poured into a slag stewing pit by using a crown block and stewed by using wastewater generated in the purification of washing gas water, the dephosphorization slag after stewing is subjected to magnetic separation, crushing and screening, the magnetically-separated slag steel is supplied to a steel plant to replace scrap steel, the generated dephosphorization tailings are used as road base materials, and the components of the dephosphorization slag are as follows:
TABLE 6
| Dephosphorizing slag | CaO | SiO 2 | P 2 O 5 | FeO (gao) | Metallic Fe | TFe | Al 2 O 3 | R |
| Composition of | ≥30 | ≤20 | ≥5 | ≥15 | ≥8 | ≥3 | ||
| Target value | 40 | 10 | 10 | 23 | 10 | 28 | 3 | 4.0 |
Example 2
In the embodiment, the liquid converter slag, the hot desulfurization slag, the carbonaceous reducing agent and the silicon-containing raw material are subjected to reduction smelting to obtain reduced molten iron and reduced slag with the Tfe content of less than or equal to 4% and the alkalinity of 1; wherein the temperature is raised to 1520 ℃ end point temperature at the speed of 4 ℃/min at 1100 ℃ initial temperature in the reduction smelting; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100:13:23; the other steps are the same as in example 1.
Example 3
In the embodiment, the liquid converter slag, the hot desulfurization slag, the carbonaceous reducing agent and the silicon-containing raw material are subjected to reduction smelting to obtain reduced molten iron and reduced slag with the Tfe content of less than or equal to 4% and the alkalinity of 1.4; wherein, the temperature is increased to the end temperature of 1540 ℃ at the speed of 5 ℃/min at the initial temperature of 1200 ℃ in the reduction smelting; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100:7:17; the other steps are the same as in example 1.
Comparative example 1
The comparative example adopts the traditional slag stewing process.
Comparative example 2
In this comparative example, the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent, and the mass of the silicon-containing raw material was 100:5:10; the other steps were the same as in example 1.
Comparative example 3
In this comparative example, the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent, and the mass of the silicon-containing raw material was 100:10:30, of a nitrogen-containing gas; the other steps were the same as in example 1.
Comparative example 4
In the comparative example, the alkalinity of the reducing slag in the reduction smelting is 0.8; the other steps were the same as in example 1.
Experimental example 1
1. Recovery rate
The recovery rates of iron, heat and slag in examples 1 to 3 and comparative examples 1 to 4 were counted as shown in Table 7.
TABLE 7
From the data in table 7 it can be seen that:
in the comparative example 1, the traditional slag stewing process is implemented, so that the recovery rate of iron is low, heat is not utilized, and the treated tailings cannot be utilized with high added value;
in comparative example 2, the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent, and the mass of the raw material containing silicon was 100:5:10, out of the scope of the embodiment of the invention, the reduction rate of iron is insufficient, and the slag is not completely modified;
in comparative example 3, the ratio of the total mass of the liquid converter slag and the hot desulfurization slag, the mass of the carbonaceous reducing agent, and the mass of the silicon-containing raw material was 100:10:30, of a nitrogen-containing gas; outside the scope of the embodiment of the invention, the slag modification is excessive, and the slag activity is low due to the excessive addition of silica;
in comparative example 4, the basicity of the reducing slag in the reduction smelting is 0.8, which is smaller than the range of the embodiment of the invention, the slag modification is excessive, and the slag activity is low due to the large adding amount of silica;
in examples 1 to 3 of the present invention, the recovery rate of the slag metallic iron was high (50% higher than that in the slag stewing process). It can be seen that the parameters of the reduction smelting in the embodiment of the invention are different and are matched together, and the subsequent comprehensive recycling of the coal gas and heat generated during the reduction smelting, the recycling of the reduction slag and the recycling of the reduced molten iron are carried out, so that the problem of the comprehensive utilization of iron, heat and slag of converter steel slag and desulphurization slag in steel mills is solved.
2. Economic and social benefits
1. Economic benefits
The following is the measurement and calculation of the production cost by the 1 ton reduction method:
TABLE 8
As can be seen from table 8, by using the method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag provided by the embodiment of the present invention, the yield of about 150 yuan per ton of slag can be generated when 1 ton of liquid steel slag and hot desulfurized slag are processed, the yield of about 30 yuan per ton of slag is greatly improved when compared with the yield of about 30 yuan per ton of slag when 1 ton of liquid steel slag and hot desulfurized slag are processed by the slag stewing process, and the yield can be expected to be increased by 1.2 billion yuan per 100 ten thousand tons of slag per year.
2. Social benefits
The process basically solves the problem of comprehensive benefits of the desulfurized slag and the converter slag generated by steel plants, reduces the problem that the tailings occupy the land indiscriminately, and has a certain demonstration effect.
Finally, it should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (7)
1. A comprehensive utilization method of iron, heat and slag of converter slag and desulfurized slag is characterized by comprising the following steps:
reducing and smelting liquid converter slag, hot desulfurization slag, a carbonaceous reducing agent and a silicon-containing raw material to obtain reduced molten iron with the P content of 1.6-2 percent and reduced slag with the TFe content of less than or equal to 4 percent and the alkalinity of 1.2 +/-0.2; the hot desulfurization slag comprises the following chemical components in percentage by mass: caO:30% -35% of SiO 2 ：12%～20%，MgO：15%，S：0.5%～1.0%，FeO：8%～10%，TFe：8%～14%，Al 2 O 3 :6 percent, and the balance of inevitable impurities;
the liquid converter slag comprises the following chemical components in percentage by mass: caO:45 to 48 percent of SiO 2 ：15%～20%，MgO：8%～12%，P 2 O 5 ：1%～1.5%，FeO：15%～23%，Fe：8%～10%，TFe:28%，Al 2 O 3 :3% and the rest isUnavoidable impurities;
in the reduction smelting, the temperature is increased to 1530 +/-10 ℃ at the initial temperature of more than or equal to 1000 ℃ and the speed of 4-5 ℃/min; the ratio of the total mass of the liquid converter slag and the thermal desulfurization slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100: (7-13): (17-23); wherein the carbonaceous reducing agent comprises at least one of coke powder and anthracite; the siliceous feedstock comprises at least one of silica, bauxite, and iron-containing tailings;
comprehensively recycling the coal gas and heat generated in the reduction smelting to obtain qualified coal gas and qualified steam;
water quenching is carried out on the reducing slag to form water granulated slag, and the water granulated slag is dried by utilizing the generated steam to obtain dry slag;
adding a recarburized agent into the reduced molten iron with the P content of 1.6-2% for recarburization to obtain recarburized molten iron, and then carrying out first top powder spraying dephosphorization on the recarburized molten iron by adopting passivated lime powder, oxygen and iron scale to obtain dephosphorization water with the P content of less than 0.30%; carrying out second top powder spraying dephosphorization on the dephosphorization water with the P content of less than 0.30% by adopting passivated lime powder, oxygen and iron oxide scale to obtain dephosphorization molten iron with the P content of less than 0.080%;
the dephosphorized molten iron is supplied to a converter for smelting to obtain dephosphorized slag;
and carrying out slag stewing treatment on the dephosphorized slag, and then carrying out magnetic separation, crushing and screening to obtain dephosphorized tailings for preparing road base materials and slag steel for replacing scrap steel in a steel plant.
2. The method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag according to claim 1, wherein the reduction smelting of liquid converter slag, hot desulfurized slag, carbonaceous reducing agent and siliceous material comprises:
and (3) pouring the liquid converter slag and the desulfurized slag into a slag ladle, hoisting the slag ladle to an electric furnace, and adding a carbonaceous reducing agent and a silicon-containing raw material for reduction smelting.
3. The method for comprehensive utilization of iron, heat and slag of converter slag and desulfurized slag according to claim 1, wherein bottom blowing N is used in said reduction smelting 2 To effect agitation.
4. The method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag according to claim 1, wherein the ratio of the total mass of the liquid converter slag and the hot desulfurized slag, the mass of the carbonaceous reducing agent and the mass of the silicon-containing raw material is 100:10:20.
5. the method according to claim 1, wherein the reducing slag comprises TFe of not more than 4% and alkalinity is 1.2 + -0.2, the reduction smelting is stopped, and slag tapping is performed, wherein during slag tapping, the slag tapping is monitored, when liquid molten iron is monitored, a sliding plate slag stopping mechanism is used for rapidly closing a slag outlet, and a slag-iron separation dam is arranged in a slag tapping channel.
6. The method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag according to claim 1, wherein when the recarburizing agent is added to the reduced molten iron for recarburization, the recarburizing agent is added to the two bags of reduced molten iron after the two bags of reduced molten iron are mixed uniformly.
7. The method for comprehensively utilizing iron, heat and slag of converter slag and desulfurized slag according to claim 1, wherein the comprehensive recycling of coal gas and heat generated during the reduction smelting is performed to obtain qualified coal gas and qualified steam, and comprises the following steps:
firstly, reducing the temperature of the flue gas from 1400 +/-20 ℃ to 800 +/-20 ℃ by utilizing vaporization cooling, and leading the generated supersaturated steam to flow into a steam pipe network after passing through a heat accumulator;
then water mist is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 800 +/-20 ℃ to less than or equal to 200 ℃, after fine dedusting is carried out by a high-temperature dedusting cloth bag, water is adopted for spraying, dedusting and cooling, the temperature of the flue gas is reduced from 150 +/-20 ℃ to less than 70 ℃, and clean coal gas with the coal gas CO of more than or equal to 30% is obtained and is merged into a coal gas pipe network.
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| CN106755654A (en) * | 2016-12-10 | 2017-05-31 | 东北大学 | A kind of method of slag metallurgy melting also original production |
| CN108359758A (en) * | 2018-02-27 | 2018-08-03 | 首钢京唐钢铁联合有限责任公司 | A kind of method and its application by desulfurization slag and the hot mixed processing of vessel slag |
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