CN115679037A - Self-circulation absorption and utilization method and system for steelmaking dust of electric arc furnace - Google Patents
Self-circulation absorption and utilization method and system for steelmaking dust of electric arc furnace Download PDFInfo
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Abstract
The invention discloses a self-circulation absorption and utilization method of electric arc furnace steelmaking dust and a corresponding system, in the method, the electric arc furnace steelmaking dust, carbon powder and lime powder are mixed according to a certain adding amount and proportion, and are sprayed into a molten pool of the electric arc furnace at a certain injection speed in a pneumatic conveying mode, then the dust is subjected to a melting reduction process in the molten pool, and reduction products respectively enter a metal molten pool, molten slag and regenerated dust, so that the high-efficiency cyclic utilization of ferrite resources in the electric arc furnace dust and the cyclic enrichment of zinc resources are realized, and the discharge of solid wastes is reduced. The whole system operation process, electric arc furnace steelmaking dust do not contact with external environment, solve the environmental pollution problem that electric arc furnace steelmaking dust caused, improve electric arc furnace steelmaking metallurgical effect simultaneously, reduction in production cost.
Description
Technical Field
The invention belongs to the technical field of metallurgical solid waste resource utilization, and particularly relates to a self-circulation absorption and utilization method of electric arc furnace steelmaking dust and a system used by the method.
Background
In the process of electric arc furnace steelmaking, due to rapid heating of the electric arc furnace and violent stirring at high temperature (1600 ℃), metal evaporation is carried out of the furnace body by the ascending hot gas flow, oxidized, vulcanized or chlorinated in a dust collection system, and oxides in slag are directly carried into the dust collection system by the hot gas flow and finally deposited in a bag dust collector to form electric arc furnace steelmaking dust. An electric arc furnace produces 10 to 20kg of dust per ton of steel produced. The electric arc furnace steelmaking dust belongs to solid hazardous waste, has complex chemical components, mainly contains Fe and Zn, and also contains some trace metal elements such as Pb, cr, cd, cu, ag and the like. A large amount of steel-making dust of the electric arc furnace is accumulated, so that metal resources and land resources are wasted, and if the electric arc furnace is placed in the open air, heavy metals can permeate into the ground under the action of rainwater, so that underground water pollution is caused.
The electric arc furnace steelmaking dust contains about 40 percent of valuable elements such as Fe, about 10 percent of Zn and the like, and is a recyclable resource. At present, the main treatment modes of the steelmaking dust of an electric arc furnace comprise harmless treatment and landfill, blast furnace injection, ball pressing, rotary hearth furnace recycling and the like. Wherein, the harmless treatment and landfill can not realize the utilization of metal resources in the steelmaking dust of the electric arc furnace; after the blast furnace recycles the steelmaking dust of the electric arc furnace, the dust contains Zn, which can cause blast furnace nodulation and influence the smooth operation of the blast furnace; the ball pressing process increases the treatment cost of the steelmaking dust of the electric arc furnace; the processing capacity of the rotary hearth furnace is limited, the whole effective processing of the electric arc furnace steelmaking dust cannot be met, and in addition, the electric arc furnace steelmaking dust has high zinc content and large viscosity, so that the problems of material bin caking, uniform mixing, heat exchanger blockage aggravation and the like in the rotary hearth furnace processing process are easily caused.
Currently, patent application cn200710024770.x discloses a method for treating zinc-containing electric furnace dust, which comprises the following steps: carrying out carbon preparation, pelletizing and drying on the zinc-containing electric furnace dust to prepare carbon-containing pellets; loading the dried carbon-containing pellets into a rotary hearth furnace, and carrying out high-temperature reduction roasting; introducing Zn steam in the rotary hearth furnace into an oxidation chamber for oxidation to generate ZnO steam; introducing ZnO vapor into a cooling chamber to obtain ZnO powder; introducing ZnO powder into a dust collection chamber; and introducing the carbon-containing pellets treated by the rotary hearth furnace into a cooling machine to obtain semi-metallized pellets. The method uses the direct reduction roasting treatment technology of the carbon-added pellets to treat the zinc-containing electric furnace dust, can realize the comprehensive utilization of the electric furnace dust, and has better environmental protection benefit and economic benefit. The method for carrying out carbon thermal reduction on electric furnace dust by using the rotary hearth furnace has the advantages of higher treatment temperature, higher energy consumption, higher required equipment investment, limited treatment capacity of the rotary hearth furnace and incapability of realizing the effective treatment of the electric furnace steelmaking dust.
Patent application CN201910035940.7 discloses a method for recovering zinc by comprehensive utilization of steelmaking dust, which comprises the steps of mixing steelmaking dust with carbon powder and boron trioxide, pressing the mixture into pellets under the pressure of 11-19Mpa, sending the pellets into a vacuum carbon tube furnace, controlling the reaction temperature to be 850-950 ℃ under the vacuum degree of 10-100 Pa, carrying out constant-temperature treatment for 80-100 min, carrying out vacuum roasting to obtain gaseous elemental zinc volatile, condensing the volatile into solid after passing through a condensation collector, and collecting the solid to obtain high-purity zinc ingots. The method promotes the reduction of zinc in the steelmaking dust, realizes the recycling of the steelmaking dust, obtains high-quality zinc ingots, reduces the energy consumption during the control of vacuum conditions in the steelmaking dust treatment process, can effectively evaporate the zinc in the steelmaking dust by vacuum reduction, achieves the aim of condensing and collecting simple substance zinc, and ensures that the recovery rate of the zinc in the steelmaking dust is as high as 97.76%. However, the method needs separate pelletizing equipment and vacuum roasting equipment, and needs to add a large amount of flux and organic binder, thereby increasing the treatment cost of the steelmaking dust of the electric arc furnace.
Disclosure of Invention
In order to solve the problem of dust treatment of electric arc furnace steelmaking, the invention provides a method and a corresponding system for self-circulation absorption and utilization of the electric arc furnace steelmaking dust, which can effectively recycle the ferrite resource in the electric arc furnace steelmaking dust, realize the circulation enrichment of the zinc resource, reduce the discharge of solid wastes and avoid the secondary pollution to the environment.
Collecting electric arc furnace steelmaking dust, mixing the collected electric arc furnace steelmaking dust with carbon powder and lime powder according to a certain proportion, continuously spraying the mixed material into an electric arc furnace molten pool in a pneumatic conveying mode, then melting and reducing the electric arc furnace steelmaking dust under the high-temperature condition of the molten pool, reducing part of iron in the electric arc furnace steelmaking dust into molten steel, reducing zinc into regenerated dust, and adding the rest of components into slag.
The method specifically comprises the following steps:
s1, collecting steelmaking dust of an electric arc furnace through a sealed dust removal pipeline, then grinding the steelmaking dust in a dust closed pretreatment device, putting the steelmaking dust into a dust closed storage bin for later use after the treatment is finished, and simultaneously carrying out chemical analysis on a dust sample to determine components;
s2, confirming the mass ratio of the scrap steel and the molten iron added during smelting in the electric arc furnace;
s3, determining the adding proportion of the carbon powder and the lime powder according to the information obtained in the S1 and the S2, and calculating the injection amount of the mixed material of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder into the molten pool of the electric arc furnace;
s4, according to the injection amount of the mixed materials determined in the S3, adding the electric arc furnace dust, the carbon powder and the lime powder into a smelting injection tank through a premix bin respectively;
s5, after the furnace burden in the electric arc furnace is completely melted by electrifying, starting to spray the mixed material into the electric arc furnace molten pool until the mixed material is completely sprayed;
and S6, during the smelting of the electric arc furnace, after the generated dust is collected by the closed dust removal processing system, repeating the steps S1-S5 until the zinc content in the electric arc furnace steelmaking dust is 25% -30%, and then, the electric arc furnace steelmaking dust is not recycled and is used as a raw material of a zinc smelting system for subsequent processing. The reason is that when the zinc content reaches 25%, even if the circulation is continued, the zinc content in the dust is increased in a limited range, and the zinc can be used as a zinc extraction raw material to produce good economic benefits.
Preferably, the adding amount and the mixing ratio of the materials in the S3 are determined according to the composition of the raw materials entering the furnace during smelting in an electric arc furnace, the raw materials entering the furnace are scrap steel and molten iron, the amount of the dust generated by adding the steel into the electric arc furnace is determined according to the mass fraction of the scrap steel in the raw materials entering the furnace, the total mole number of zinc and iron in the dust generated by adding the steel into the electric arc furnace is calculated, and finally, the mole number of the added carbon powder and the added lime is calculated according to the C/Zn mole ratio and the Ca/Fe mole ratio, and the specific method is as follows:
(1) When the mass fraction of the scrap steel in the raw materials fed into the electric arc furnace is 20%, adding 17-20kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 2.0.
(2) When the mass fraction of the scrap steel in the raw materials fed into the electric arc furnace is 40%, adding 14-17kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 1.8.
(3) When the mass fraction of the scrap steel in the raw materials charged into the electric arc furnace is 60%, adding 11-14kg/t steel into the steel-making dust of the electric arc furnace, adding the added carbon powder according to the C/Zn molar ratio of 1.6, and adding the added lime powder according to the Ca/Fe molar ratio of 1.4.
(4) When the mass fraction of the scrap steel in the charging raw materials of the electric arc furnace is 80%, adding 8-11kg/t steel into the steelmaking dust of the electric arc furnace, adding carbon powder according to the proportion that the C/Zn molar ratio is 1.4.
(5) When the mass fraction of the scrap steel in the raw materials fed into the electric arc furnace is 100%, adding 5-8kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 1.2.
The self-circulation absorption and utilization system of the steelmaking dust of the electric arc furnace adopted by the method comprises the following steps: a dust closed collection pretreatment system, a premixing system and a smelting system, wherein,
the dust closed collection pretreatment system is used for continuously collecting and grinding the steelmaking dust of the electric arc furnace from the sealed dust removal pipeline;
the pre-mixing system is used for receiving the electric arc furnace steelmaking dust output by the dust closed collection pre-processing system and pre-mixing the electric arc furnace steelmaking dust with carbon powder and lime powder to obtain a mixed material;
the smelting system comprises an electric arc furnace molten pool which is used for receiving the mixed materials output by the premixing system for smelting and returning the obtained regenerated dust to the dust closed collection pretreatment system.
Preferably, the self-circulation absorption and utilization system for steelmaking dust in the electric arc furnace further comprises a gas supply system and a computing system,
the gas supply system is used for providing a blowing gas source for the dust closed collection pretreatment system, the premixing system and the smelting system;
and the calculation system is connected with the premixing system and the smelting system and is used for calculating the adding amount and the injection speed of the carbon powder, the lime powder and the steelmaking dust of the electric arc furnace as well as the adding amount and the injection speed of the mixed material into a molten pool of the electric arc furnace.
Preferably, the dust closed collection pretreatment system comprises a closed collection device, a closed pretreatment device and a dust closed storage bin which are connected in sequence, wherein,
the closed collecting device is used for collecting the electric arc furnace steelmaking dust output from the sealed dust removal pipeline;
the closed pretreatment device is used for grinding the electric arc furnace steelmaking dust output by the closed collection device to make the granularity of the electric arc furnace steelmaking dust uniform;
the dust closed storage bin comprises two bins, wherein one bin is used for storing ground electric arc furnace steelmaking dust and sending the ground electric arc furnace steelmaking dust into the dust injection tank, and the other bin is used for receiving regenerated dust output by the smelting system.
Preferably, the premixing system comprises a carbon powder injection tank, a lime powder injection tank, a dust injection tank, a premixing silo and a smelting injection tank, wherein,
the discharge ports of the carbon powder injection tank, the lime powder injection tank and the dust injection tank are connected with a feed port of a pre-mixing silo, and the pre-mixing silo is used for pre-mixing the carbon powder, the lime powder and the electric arc furnace steelmaking dust output from the carbon powder injection tank, the lime powder injection tank and the dust injection tank to obtain a mixed material;
the discharge hole of the pre-mixing bin is connected with the feed inlet of the smelting injection tank, and the smelting injection tank is used for injecting the mixed materials into an electric arc furnace molten pool.
The reaction principle of the invention is as follows: the dust generated in the electric arc furnace steelmaking is injected into an electric arc furnace molten pool, lime reacts with zinc ferrite and zinc chloride in the electric arc furnace steelmaking dust at the electric arc furnace steelmaking temperature to generate zinc oxide, the generated zinc oxide and the original zinc oxide in the dust can be reduced into zinc vapor by carbon powder to enter a dust collecting system, and iron oxide in the dust can be reduced by the carbon powder to enter molten steel, so that the high-efficiency cyclic utilization of ferrite resources in the electric arc furnace dust and the cyclic enrichment of zinc resources are realized, and the emission of solid wastes is reduced. The electric arc furnace steelmaking dust does not contact with the external environment in the operation process of the whole system, so that the problem of environmental pollution caused by the electric arc furnace steelmaking dust is solved, the metallurgical effect of the electric arc furnace steelmaking is improved, and the production cost is reduced.
Preferably, the electric arc furnace molten pool is provided with spray guns, the mixed materials can be sprayed by one or more of a buried spray gun, a furnace door spray gun and a furnace wall spray gun, each spray gun is designed by 1~2, and the single-gun powder spraying speed is adjustable within the range of 0-50 kg/min. Conveying the electric arc furnace steelmaking dust, the carbon powder, the lime powder and the mixed material to an inlet of an electric arc furnace spray gun in a closed pipeline in a pneumatic conveying mode; and when all the scrap steel in the electric arc furnace is electrified and melted, the mixed material starts to be blown.
Preferably, the electric arc furnace steelmaking dust is ground in a dust closed collection pretreatment system to a uniform particle size. If a furnace door or a furnace wall spray gun is adopted for blowing, the granularity is required to be 1 to 2mm; if an embedded oxygen lance is used for blowing, the dust granularity is required to be between 100 and 150 meshes.
Preferably, the mixed material falls to a spray gun from a smelting injection tank during injection and is mixed with a main blowing gas for injection, and the flow rate of the main blowing gas of a single gun is 200 to 500Nm 3 H, pressure of 0.4 to 1.0Mpa, and carrier gas of N 2 。
Preferably, the dust containment silo is provided with two chambers for alternate charging, one for storing and delivering the eaf steelmaking dust to the dust injection tank and the other for receiving the regenerated dust. After the dust is blown, the regenerated dust generated in the smelting process of the electric arc furnace can be continuously stored by the closed collecting system for later use, and the recycling is realized according to the steps S1 to S5.
After the electric arc furnace steelmaking dust is treated by the method, the content of Fe in the obtained regenerated dust is reduced, the content of Zn is increased, and the total amount of dust generated in the electric arc furnace steelmaking process is reduced.
The method is suitable for an electric arc furnace of 50 to 300t.
The technical scheme of the invention has the following beneficial effects:
the invention provides a self-circulation absorption and utilization method of electric arc furnace steelmaking dust and a corresponding system, wherein a slag phase and a metal molten pool phase exist in an electric arc furnace, the electric arc furnace steelmaking dust, carbon powder and lime powder are mixed according to a certain adding amount and a certain proportion, and then are sprayed into the electric arc furnace molten pool at a certain spraying speed in a pneumatic conveying mode, the dust is subjected to a melting reduction process in the molten pool, and reduction products respectively enter the metal molten pool, molten slag and regenerated dust, so that the high-efficiency recycling of ferrite resources in the electric arc furnace dust and the cyclic enrichment of zinc resources are realized, and the discharge of solid wastes is reduced. The whole system operation process, electric arc furnace steelmaking dust do not contact with external environment, solve the environmental pollution problem that electric arc furnace steelmaking dust caused, improve electric arc furnace steelmaking metallurgical effect simultaneously, reduction in production cost.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an electric arc furnace steelmaking dust self-circulation absorption and utilization system according to the present invention;
the reference numerals are explained below:
1-dust closed collection pretreatment system;
11-sealing the dust removal pipeline; 12-enclosing the collecting device;
13-closing the pretreatment device; 14-dust closed storage;
2-a premix system;
21-a carbon powder injection tank; 22-a lime powder injection tank; 23-dust spray tank;
24-a pre-mixing bin; 25-a smelting injection tank;
3-a smelting system;
31-electric arc furnace bath; 32-a spray gun;
4-a gas supply system;
5-computing system.
Detailed Description
The technical solutions and the technical problems to be solved in the embodiments of the present invention will be described below with reference to the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the patent of the invention, not all embodiments.
As shown in FIG. 1, the invention provides a self-circulation dust-absorption and utilization system for electric arc furnace steelmaking, which comprises a dust closed collection and treatment system 1, a premixing system 2, a calculation system 5, a smelting system 3 and a gas supply system 4. Wherein the content of the first and second substances,
the dust closed collection pretreatment system 1 is used for continuously collecting and grinding the steelmaking dust of the electric arc furnace from the sealed dust removal pipeline 11. The premixing system 2 is used for receiving the electric arc furnace steelmaking dust output by the dust closed collection pretreatment system 1, and premixing the electric arc furnace steelmaking dust with carbon powder and lime powder to obtain a mixed material. The smelting system 3 comprises an electric arc furnace molten bath 31 which is used for receiving the mixed materials output from the premixing system 2 for smelting and returning the obtained regenerated dust to the dust closed collection pretreatment system 1. And the gas supply system 4 is used for providing blowing gas sources for the dust closed collection pretreatment system 1, the premixing system 2 and the smelting system 3. The calculation system 5 is connected with the premixing system 2 and the smelting system 3 and is used for calculating the adding amount and the injection speed of the carbon powder, the lime powder and the electric arc furnace steelmaking dust, and the adding amount and the injection speed of the mixed material into the electric arc furnace molten pool 31.
Further, the dust closed collection pretreatment system 1 comprises a closed collection device 12, a closed pretreatment device 13 and a dust closed storage bin 14 which are connected in sequence. Wherein the closed collecting device 12 is used for collecting the electric arc furnace steelmaking dust output from the sealed dust removing pipeline 11. The closed pretreatment device 13 is used for grinding the electric arc furnace steelmaking dust output by the closed collection device 12 to make the granularity of the electric arc furnace steelmaking dust uniform. The dust containment silo 14 comprises two silos, one for storing ground eaf dust and delivering it to the dust injection tank 23 and the other for receiving recycled dust output by the smelting system 3.
Further, the premixing system 2 includes a carbon powder injection tank 21, a lime powder injection tank 22, a dust injection tank 23, a premix bin 24, and a smelting injection tank 25. The discharge ports of the carbon powder injection tank 21, the lime powder injection tank 22 and the dust injection tank 23 are connected with the feed port of the premix bin 24, and the premix bin 24 is used for premixing the carbon powder, the lime powder and the electric arc furnace steelmaking dust output from the carbon powder injection tank 21, the lime powder injection tank 22 and the dust injection tank 23 to obtain a mixed material. The discharge hole of the pre-mixing bin 24 is connected with the feed inlet of the smelting injection tank 25, and the smelting injection tank 25 is used for injecting the mixed materials into an electric arc furnace molten pool 31.
The working process of the self-circulation absorption and utilization system for steelmaking dust of the electric arc furnace is as follows: the steelmaking dust of the electric arc furnace enters a closed collecting device 12 through a sealed dust removing pipeline 11, is ground in a closed pretreatment device 13 and then enters a dust closed storage bin 14 for standby. The steel-making dust, carbon powder and lime in the electric arc furnace are added into a premix bin 24 through a dust injection tank 23, a carbon powder injection tank 21 and a lime powder injection tank 22 according to the adding amount and proportion of the mixed materials calculated by the calculation system, and then are conveyed into a smelting injection tank 25. After the scrap steel in the electric arc furnace is completely melted, the smelting injection tank 25 injects the mixture into the molten pool 31 of the electric arc furnace through the furnace door spray gun, the furnace wall spray gun and the submerged spray gun at a predetermined injection speed until the smelting is finished.
Example 1
The invention is applied to a 100t electric arc furnace, the type of the smelted steel is common carbon steel, and the raw materials of the smelted steel in the electric arc furnace comprise 60 percent of scrap steel and 40 percent of molten iron. The electric arc furnace steelmaking dust is analyzed by chemical components, wherein the mass fraction of T.Fe is 35%, and the mass fraction of T.Zn is 15%. The specific smelting process is as follows:
(1) Collecting steelmaking dust of an electric arc furnace through a sealed dust removal pipeline, then treating the steelmaking dust in a dust closed pretreatment system, after the treatment is finished, putting the steelmaking dust into a dust closed storage bin for standby, and after chemical analysis is carried out on a dust sample, determining that the components of the steelmaking dust are 35% of Fe and 15% of Zn;
(2) According to the chemical components of the dust and the composition of the raw materials entering the furnace, the computing system determines that the pre-mixing proportion of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder is as follows: the amount of the added electric arc furnace dust is 11 to 14kg/t steel, and the intermediate value is 12kg/t steel. The amount of the carbon powder is added according to the ratio of C/Zn molar ratio of 1.6.
For an electric arc furnace with the volume of 100t, the total dust injection amount is 1.2t, wherein T.Fe is 1.2t multiplied by 35% =0.42t, and the mole number is 7.5mol; t.zn is 1.2t × 15% = =0.18t, the number of moles is 2.77mol.
The amount of carbon powder added is 4.43mol, namely 53kg; the lime is added in an amount of 10.5mol, namely 588kg;
the calculation system calculates the weight of the mixed materials required to be added in production according to the smelting process of the electric arc furnace and the characteristics of the product: 1.2t of steelmaking dust in an electric arc furnace, 53kg of carbon powder and 588kg of lime powder, wherein the weight of the mixture is 1841kg. The blowing time is 20min, and the blowing speed of the mixed material during smelting is 1841 kg/20min =92kg/min;
(3) Before smelting begins, the premixing system pre-mixes the determined amount of electric arc furnace steelmaking dust, carbon powder and lime powder according to the information of the computing system and then pneumatically conveys the pre-mixed amount of electric arc furnace steelmaking dust, carbon powder and lime powder to a smelting injection tank through a sealed pipeline;
(4) When the smelting starts, the smelting injection tank injects the mixed material of the steelmaking dust of the electric arc furnace into the molten pool of the electric arc furnace through a furnace door spray gun, a furnace wall spray gun and/or an embedded spray gun at the speed of 92kg/min through a sealed pipeline until the smelting of the current furnace is finished;
(5) During the whole smelting period, the dust closed collecting and processing system continuously collects and grinds the steelmaking dust of the electric arc furnace from the sealed dust removing pipeline. The steps (1) to (5) are circulated for 3 times, and when the Zn concentration in the steelmaking dust of the electric arc furnace reaches 25 to 30 percent, the steelmaking dust does not enter a smelting system any more and is treated as a raw material for zinc smelting. Compared with the electric arc furnace steelmaking dust originally collected in the step (1), the total amount of the regenerated dust obtained after the treatment by the method is reduced by 12 percent, the mass content of Fe is reduced by 8 percent, and the mass content of Zn is increased by 10 percent.
In conclusion, the method can realize the high-efficiency recycling of the ferrite resource and the recycling enrichment of the zinc resource, reduce the dust discharge amount, realize the recycling of the steelmaking dust of the electric arc furnace for 5-20kg/t steel and achieve the comprehensive cost and economic benefit of 10-20 yuan/t steel.
Example 2
The invention is applied to a 150t electric arc furnace, the type of the smelted steel is common carbon steel, and the composition of the raw materials fed into the electric arc furnace during smelting is 100 percent of scrap steel. The electric arc furnace steelmaking dust is analyzed by chemical components, wherein the mass fraction of T.Fe is 30%, and the mass fraction of T.Zn is 20%. The specific smelting process is as follows:
(1) Collecting steelmaking dust of the electric arc furnace through a sealed dust removal pipeline, then treating the steelmaking dust in a dust closed pretreatment system, after the treatment is finished, putting the steelmaking dust into a dust closed storage bin for later use, and after chemical analysis is carried out on a dust sample, determining that the components of the steelmaking dust are 30% in Fe content and 20% in Zn content;
(2) According to the chemical components of the dust and the composition of the raw materials entering the furnace, the computing system determines that the pre-mixing proportion of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder is as follows: the amount of dust added to the electric arc furnace is 5 to 8kg/t steel, and the median value is 6kg/t steel. The amount of the carbon powder is added according to the ratio of C/Zn molar ratio of 1.2 to 1, and the amount of the lime is added according to the ratio of Ca/Fe molar ratio of 1.2 to 1.
The calculation system calculates the weight of the mixed materials required to be added in the production according to the smelting process of the electric arc furnace and the characteristics of the product: 0.9t of electric arc furnace steelmaking dust, 40kg of carbon powder and 325kg of lime powder = 1265kg. The blowing time is 20min, and the blowing speed of the mixed material is 1265 kg/20min/64kg/min during smelting;
steps (3) to (5) were the same as in example 1.
The steps (1) to (5) are circulated for 2 times, and when the Zn concentration in the steelmaking dust of the electric arc furnace reaches 25 to 30 percent, the steelmaking dust does not enter a smelting system any more and is treated as a raw material for zinc smelting. Compared with the electric arc furnace steelmaking dust originally collected in the step (1), the total amount of the regenerated dust obtained after the treatment by the method is reduced by 10 percent, the mass content of Fe is reduced by 5 percent, and the mass content of Zn is increased by 8 percent.
Example 3
The invention is applied to a 100t electric arc furnace, the type of the smelted steel is common carbon steel, and the raw materials fed into the electric arc furnace during smelting comprise 20 percent of scrap steel and 80 percent of molten iron. The electric arc furnace steelmaking dust is analyzed by chemical components, wherein the mass fraction of T.Fe is 40%, and the mass fraction of T.Zn is 10%. The specific smelting process is as follows:
(1) Collecting steelmaking dust of the electric arc furnace through a sealed dust removal pipeline, then treating the steelmaking dust in a dust closed pretreatment system, after the treatment is finished, putting the steelmaking dust into a dust closed storage bin for later use, and after chemical analysis is carried out on a dust sample, determining that the components of the steelmaking dust are 40% of Fe and 10% of Zn;
(2) According to the chemical components of the dust and the composition of the raw materials entering the furnace, the computing system determines that the pre-mixing proportion of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder is as follows: the amount of the dust added into the electric arc furnace is 17-20kg/t steel, and the intermediate value is 18kg/t steel. The amount of the carbon powder is added according to the ratio of C/Zn molar ratio of 2.0.
The calculation system calculates the weight of the mixed materials required to be added in the production according to the smelting process of the electric arc furnace and the characteristics of the product: 1.8t of steelmaking dust in an electric arc furnace, 66kg of carbon powder and 1154kg of lime powder = 3020kg. The blowing time is 20min, and the blowing speed of the mixed material during smelting is 3020 kg/20min =151kg/min;
steps (3) to (5) were the same as in example 1.
The steps (1) to (5) are circulated for 3 times, and when the Zn concentration in the steelmaking dust of the electric arc furnace reaches 25 to 30 percent, the steelmaking dust does not enter a smelting system any more and is treated as a raw material for zinc smelting. Compared with the electric arc furnace steelmaking dust originally collected in the step (1), the total amount of the regenerated dust obtained after the treatment by the method is reduced by 13 percent, the mass content of Fe is reduced by 10 percent, and the mass content of Zn is increased by 15 percent.
Comparative example
The tonnage of the electric arc furnace, the composition of the raw materials entering the furnace and the composition of the steelmaking dust of the electric arc furnace are the same as those in the embodiment 1, and the difference is that in the step (2), according to the chemical composition of the dust and the composition of the raw materials entering the furnace, the calculation system determines the premixing proportion of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder as follows: the amount of the added electric arc furnace dust is 11 to 14kg/t steel, and the intermediate value is 12kg/t steel. The amount of the carbon powder is added according to the ratio of C/Zn molar ratio of 1.2 to 1, and the amount of the lime is added according to the ratio of Ca/Fe molar ratio of 1.0 to 1.
For an electric arc furnace with the volume of 100t, the total dust injection amount is 1.2t, wherein T.Fe is 1.2t multiplied by 35% =0.42t, and the mole number is 7.5mol; t.zn is 1.2t × 15% = =0.18t, the number of moles is 2.77mol.
3.33mol of carbon powder needs to be added, namely 40kg; adding lime in an amount of 7.5mol, namely 420kg;
the calculation system calculates the weight of the mixed materials required to be added in production according to the smelting process of the electric arc furnace and the characteristics of the product: 1.2t of electric arc furnace steelmaking dust, 40kg of carbon powder and 420kg of lime powder = 1660kg. The blowing time is 20min, and the blowing speed of the mixed material is 1660 kg/20min =83kg/min during smelting;
steps (3) to (5) were the same as in example 1.
The steps (1) to (5) are circulated for 4 times, and when the Zn concentration in the steelmaking dust of the electric arc furnace reaches 25 to 30 percent, the steelmaking dust does not enter a smelting system any more and is treated as a raw material for zinc smelting. Compared with the electric arc furnace steelmaking dust originally collected in the step (1), the total amount of the regenerated dust obtained after the treatment by the method is reduced by 8 percent, the mass content of Fe is reduced by 6 percent, and the mass content of Zn is increased by 10 percent. Therefore, the adding amount of the carbon powder and the lime powder is changed, and the circulation times are increased on the premise that the treatment effect is basically unchanged.
While the foregoing is directed to the preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications may be made therein without departing from the principles of the invention as set forth in the appended claims.
Claims (10)
1. A self-circulation absorption and utilization method of steelmaking dust of an electric arc furnace is characterized by comprising the following steps:
s1, collecting steelmaking dust of an electric arc furnace through a sealed dust removal pipeline, then grinding the steelmaking dust in a dust closed pretreatment device, putting the steelmaking dust into a dust closed storage bin for later use after the treatment is finished, and simultaneously carrying out chemical analysis on a dust sample to determine components;
s2, confirming the mass ratio of the scrap steel and the molten iron added during smelting in the electric arc furnace;
s3, determining the adding proportion of the carbon powder and the lime powder according to the information obtained in the S1 and the S2, and calculating the injection amount of the mixed material of the steelmaking dust of the electric arc furnace, the carbon powder and the lime powder to the molten pool of the electric arc furnace;
s4, adding the electric arc furnace dust, the carbon powder and the lime powder into the smelting injection tank through a premix bin respectively according to the injection amount of the mixed material determined in the S3;
s5, after the furnace burden in the electric arc furnace is completely melted by electrifying, starting to spray the mixed material into the electric arc furnace molten pool until the mixed material is completely sprayed;
and S6, during the smelting of the electric arc furnace, after the generated dust is collected by the closed dust removal processing system, repeating the steps S1-S5 until the zinc content in the electric arc furnace steelmaking dust is 25% -30%, and then, taking the electric arc furnace steelmaking dust as a raw material of the zinc smelting system for subsequent processing.
2. The self-circulation absorption and utilization method of steelmaking dust in an electric arc furnace as claimed in claim 1, wherein the material addition amount and the mixing ratio in S3 are determined according to the composition of raw materials charged into the electric arc furnace during smelting, and the specific method is as follows:
(1) When the mass fraction of the scrap steel in the charging raw materials of the electric arc furnace is 20%, adding 17-20kg/t steel into the steelmaking dust of the electric arc furnace, adding carbon powder according to the proportion that the C/Zn molar ratio is 2.0;
(2) When the mass fraction of scrap steel in the raw materials fed into the electric arc furnace is 40%, adding 14-17kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 1.8;
(3) When the mass fraction of the scrap steel in the raw materials fed into the electric arc furnace is 60%, adding 11-14kg/t steel into the steel-making dust of the electric arc furnace, adding the added carbon powder according to the C/Zn molar ratio of 1.6, and adding the added lime powder according to the Ca/Fe molar ratio of 1.4;
(4) When the mass fraction of scrap steel in the raw materials fed into the electric arc furnace is 80%, adding 8-11kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 1.4;
(5) When the mass fraction of the scrap steel in the raw materials fed into the electric arc furnace is 100%, adding 5-8kg/t steel into the electric arc furnace, adding carbon powder according to the C/Zn molar ratio of 1.2.
3. The method for self-recycling of steelmaking dust in electric arc furnace as claimed in claim 1, wherein the method employs a system for self-recycling of steelmaking dust in electric arc furnace comprising: a dust closed collection pretreatment system, a premixing system and a smelting system, wherein,
the dust closed collection pretreatment system is used for continuously collecting and grinding the steelmaking dust of the electric arc furnace from the sealed dust removal pipeline;
the pre-mixing system is used for receiving the electric arc furnace steelmaking dust output by the dust closed collection pre-processing system and pre-mixing the electric arc furnace steelmaking dust with carbon powder and lime powder to obtain a mixed material;
the smelting system comprises an electric arc furnace molten pool which is used for receiving the mixed materials output by the premixing system for smelting and returning the obtained regenerated dust to the dust closed collection pretreatment system.
4. The method of self-recycling steelmaking dust with electric arc furnace as claimed in claim 3, wherein said self-recycling steelmaking dust with electric arc furnace system further includes a gas supply system and a computing system,
the gas supply system is used for providing a blowing gas source for the dust closed collection pretreatment system, the premixing system and the smelting system;
and the computing system is connected with the premixing system and the smelting system and is used for computing the adding amount and the injection speed of the carbon powder, the lime powder and the steelmaking dust of the electric arc furnace as well as the adding amount and the injection speed of the mixed material into a molten pool of the electric arc furnace.
5. The self-circulation absorption and utilization method of steelmaking dust in an electric arc furnace as claimed in claim 3 or 4, wherein the dust closed collection pretreatment system comprises a closed collection device, a closed pretreatment device and a dust closed storage bin which are connected in sequence,
the closed collecting device is used for collecting the electric arc furnace steelmaking dust output from the sealed dust removal pipeline;
the closed pretreatment device is used for grinding the electric arc furnace steelmaking dust output by the closed collection device to make the granularity of the electric arc furnace steelmaking dust uniform;
the dust closed storage bin comprises two bins, wherein one bin is used for storing ground electric arc furnace steelmaking dust and sending the ground electric arc furnace steelmaking dust into the dust injection tank, and the other bin is used for receiving regenerated dust output by the smelting system.
6. The self-recycling method for steelmaking dust in an electric arc furnace as claimed in claim 3 or 4, wherein the premixing system comprises a carbon powder injection tank, a lime powder injection tank, a dust injection tank, a pre-mixing silo and a smelting injection tank, wherein,
the discharge ports of the carbon powder injection tank, the lime powder injection tank and the dust injection tank are connected with a feed port of a pre-mixing silo, and the pre-mixing silo is used for pre-mixing the carbon powder, the lime powder and the electric arc furnace steelmaking dust output from the carbon powder injection tank, the lime powder injection tank and the dust injection tank to obtain a mixed material;
the discharge gate of compounding storehouse in advance with the feed inlet of smelting the shooting pot is connected, it is used for with to smelt the shooting pot the misce bene is spouted into in the electric arc furnace molten bath.
7. The method of self-recycling steelmaking dust in an electric arc furnace as claimed in claim 3, wherein said electric arc furnace molten bath is provided with lances in the form of one or more of submerged lances, furnace door lances and furnace wall lances each of which is of 1~2 design, and the single lance injection rate is adjustable from 0 to 50 kg/min.
8. The self-circulation absorption and utilization method of the steelmaking dust by an electric arc furnace as claimed in claim 7, wherein the steelmaking dust by an electric arc furnace is ground in a dust closed collection pretreatment system to achieve uniform granularity, and if a furnace door or a furnace wall spray gun is adopted for blowing, the granularity is required to be 1 to 2mm; if an embedded oxygen lance is used for blowing, the dust granularity is required to be between 100 and 150 meshes.
9. According to claim 7 or 8The method for self-circulation absorption and utilization of steelmaking dust of the electric arc furnace is characterized in that a mixed material falls to a spray gun from a smelting injection tank during injection and is mixed with a main blowing gas for injection, and the flow rate of the main blowing gas of a single gun is 200 to 500Nm 3 H, pressure of 0.4 to 1.0Mpa, and carrier gas of N 2 。
10. The method for self-recycling steelmaking dust in an electric arc furnace as claimed in any one of claims 1 to 4, wherein the method is suitable for use in an electric arc furnace from 50 to 300t.
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| CN113862406A (en) * | 2021-12-06 | 2021-12-31 | 北京科技大学 | Method and system for harmless recovery treatment of stainless steel dedusting ash |
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| EP1184469A2 (en) * | 2000-08-28 | 2002-03-06 | SMS Demag AG | Process for the treatment of metal values containing dust from steelmaking |
| CN1458289A (en) * | 2002-05-15 | 2003-11-26 | 张美焦 | Method for realizing zero exhaust for fully steelmaking of steel dust and mud |
| CN101255493A (en) * | 2008-03-12 | 2008-09-03 | 中南大学 | Direct reclaiming method for metals in smelting dust |
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