CN112029949A - Method for treating zinc-containing waste steel by adopting converter full-three-step smelting process - Google Patents
Method for treating zinc-containing waste steel by adopting converter full-three-step smelting process Download PDFInfo
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- 239000011701 zinc Substances 0.000 title claims abstract description 195
- 229910052725 zinc Inorganic materials 0.000 title claims abstract description 195
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims abstract description 186
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 147
- 239000010959 steel Substances 0.000 title claims abstract description 147
- 238000003723 Smelting Methods 0.000 title claims abstract description 109
- 238000000034 method Methods 0.000 title claims abstract description 93
- 239000002699 waste material Substances 0.000 title claims abstract description 43
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 108
- 239000000428 dust Substances 0.000 claims abstract description 63
- 238000005261 decarburization Methods 0.000 claims abstract description 59
- 229910052742 iron Inorganic materials 0.000 claims abstract description 54
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 31
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 25
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 25
- 239000004571 lime Substances 0.000 claims description 25
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 20
- 239000001301 oxygen Substances 0.000 claims description 20
- 229910052760 oxygen Inorganic materials 0.000 claims description 20
- 229910052757 nitrogen Inorganic materials 0.000 claims description 11
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 5
- 238000007664 blowing Methods 0.000 claims description 5
- 239000003546 flue gas Substances 0.000 claims description 5
- 239000004615 ingredient Substances 0.000 abstract description 8
- 239000000843 powder Substances 0.000 abstract description 8
- 229910052500 inorganic mineral Inorganic materials 0.000 abstract description 6
- 239000011707 mineral Substances 0.000 abstract description 6
- 238000004064 recycling Methods 0.000 abstract description 2
- 238000002844 melting Methods 0.000 description 14
- 230000008018 melting Effects 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 229910001873 dinitrogen Inorganic materials 0.000 description 9
- 238000000605 extraction Methods 0.000 description 9
- 238000005245 sintering Methods 0.000 description 8
- 230000009286 beneficial effect Effects 0.000 description 7
- 238000009628 steelmaking Methods 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 239000002893 slag Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 2
- 238000005262 decarbonization Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229940024464 emollients and protectives zinc product Drugs 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
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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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/38—Removal of waste gases or dust
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/068—Decarburising
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Environmental & Geological Engineering (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention discloses a method for treating zinc-containing waste steel by adopting a converter full-three-removal smelting process, which comprises the following steps: adding zinc-containing waste steel into molten iron to carry out dephosphorization converter smelting, and recovering first high-zinc dust through a dust removal system in the dephosphorization smelting process to obtain low-zinc semi-molten steel; and (3) carrying out decarburization converter smelting on the low-zinc semi-molten steel, and recovering the first low-zinc dust and the second high-zinc dust through a dedusting system in the decarburization smelting process to obtain decarburized molten steel so as to finish the treatment of zinc-containing waste steel. According to the invention, the low-zinc semisteel produced by smelting in the dephosphorization furnace is added into the decarburization furnace for smelting, so that the zinc content of the produced molten steel is extremely low, and the influence of zinc on the steel quality is avoided. By recycling the low-zinc dust generated when the low-zinc semi-molten steel produced by the dephosphorization converter is smelted by the decarburization converter, the low-zinc dust can be directly used for blast furnace ingredients to replace mineral powder, the direct utilization rate of the dust reaches 48.93-49.30%, and the waste steel treatment cost of other methods is saved.
Description
Technical Field
The invention relates to the technical field of steelmaking, in particular to a method for treating zinc-containing waste steel by adopting a converter full-three-step smelting process.
Background
The total amount of scrap steel generated in the world every year is 3-4 hundred million tons at present, and accounts for 45-50% of the total steel production, wherein 85-90% of the scrap steel is used as a steelmaking raw material, and 10-15% of the scrap steel is used for casting, ironmaking and steel regeneration.
Patent application with publication number CN103614562A discloses a process for treating solid waste in steel works by a melting furnace, wherein waste materials such as zinc-containing waste steel can be added into the melting furnace according to a certain proportion to be recycled and purified to obtain zinc products with higher purity, however, the method needs to adopt the melting furnace to recycle zinc in the waste steel, and the cost is higher.
In the prior art, scrap steel is used for steelmaking, however, the quality of molten steel is reduced because the scrap steel contains zinc, and smoke generated by smelting has high zinc content and cannot be directly recycled.
Therefore, how to develop a method for treating zinc-containing scrap steel by adopting a converter full-three-step smelting process, the quality of steelmaking molten steel is not influenced while zinc is recovered, and the method becomes a key problem for research of metallurgical workers.
Disclosure of Invention
The invention aims to provide a method for treating zinc-containing waste steel by adopting a converter full-three-removal smelting process, which removes zinc in the waste steel, thereby avoiding the pollution of zinc to molten steel, and can recycle dust in the converter smelting process, wherein the dust with high zinc content is subjected to zinc extraction by a zinc extraction device, so that zinc resources are recycled, and low-zinc dust is directly used for blast furnace ingredients to replace mineral powder, thereby saving the waste steel treatment cost of other methods.
In order to achieve the above object, the present invention provides a method for treating zinc-containing scrap steel by a converter full-three-strip smelting process, the method comprising:
adding zinc-containing waste steel into molten iron to carry out dephosphorization converter smelting, and recovering first high-zinc dust through a dust removal system in the dephosphorization smelting process to obtain low-zinc semi-molten steel;
and (3) carrying out decarburization converter smelting on the low-zinc semi-molten steel, and in the decarburization smelting process, recovering the first low-zinc dust and the second high-zinc dust through a dedusting system to obtain decarburized molten steel, thereby finishing the treatment of zinc-containing waste steel.
Further, the temperature of the molten iron is 1280-1400 ℃.
Further, the weight ratio of the molten iron to the zinc-containing scrap steel is 85-90: 10 to 15.
Further, the method for adding the zinc-containing scrap steel into the molten iron for dephosphorization converter smelting specifically comprises the following steps:
adding zinc-containing waste steel into molten iron to perform dephosphorization converter smelting, and adding blocky lime into the dephosphorization converter during the dephosphorization converter smelting process, and blowing oxygen at the top and nitrogen at the bottom.
Further, the mass fraction of CaO in the blocky lime is as follows: more than or equal to 90 wt%, and the granularity of the blocky lime is 10-60 mm.
Further, in the top-blown oxygen, the supply intensity of oxygen is as follows: 0.8m3/(min.t)～2m3/(min.t)。
Further, in the bottom-blown nitrogen gas, the nitrogen gas supply intensity is as follows: 0.15m3/(min.t)～0.2m3/(min.t)。
Further, the dust removal mode of dephosphorization smelting and the dust removal mode of decarburization smelting are both dry-process electric dust removal, and the dust removal conditions of the dry-process electric dust removal include: inlet portSmoke amount 175000m3The temperature of inlet flue gas is 180-205 ℃, and the concentration of particulate matters at the inlet of the electric dust collector is less than or equal to 75g/m3The concentration of the particulate matters at the outlet of the electric dust collector is less than or equal to 15mg/m3。
Further, in the dephosphorization smelting, the mass fraction of zinc in the first high-zinc dust is more than 10%.
Further, in the decarburization smelting, the mass fraction of zinc in the first low-zinc dust is less than 0.3%, and the mass fraction of zinc in the second high-zinc dust is more than 10%.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
according to the method for treating the zinc-containing waste steel by adopting the converter full-three-strip smelting process, provided by the invention, the zinc in the waste steel is transferred into the dedusting ash in the dephosphorization converter smelting process by utilizing the characteristic of step-by-step smelting of the converter 'full-three-strip', and the dust with high zinc content is subjected to zinc extraction through a zinc extraction device by recovering the dedusting ash, so that the zinc resource is recycled. The low-zinc semisteel produced by smelting in the dephosphorization furnace is added into the decarburization furnace for smelting, so that the zinc content of the produced molten steel is extremely low, and the influence of zinc on the quality of steel is avoided. By recycling the low-zinc dust generated when the low-zinc semi-molten steel produced by the dephosphorization converter is smelted by the decarburization converter, the low-zinc dust can be directly used for blast furnace ingredients to replace mineral powder, the direct utilization rate of the dust reaches 48.93-49.30%, and the waste steel treatment cost of other methods is saved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description 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 of a method for treating zinc-containing steel scrap by adopting a converter full-three-strip smelting process provided by the embodiment of the 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 for the purpose of illustrating 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.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to an exemplary embodiment of the present invention, there is provided a method for treating zinc-containing scrap steel using a converter full-three-tap smelting process, as shown in fig. 1, including:
s1, adding zinc-containing waste steel into molten iron to perform dephosphorization converter smelting, and recovering first high-zinc dust through a dedusting system in the dephosphorization smelting process to obtain low-zinc semi-molten steel;
s2, performing decarburization converter smelting on the low-zinc semi-molten steel, and recovering the first low-zinc dust and the second high-zinc dust through a dedusting system in the decarburization smelting process to obtain decarburization molten steel and finish the treatment of zinc-containing waste steel.
The invention creatively combines the zinc-containing waste steel with the full-three-removal process,
(1) zinc in the scrap steel can be removed, so that the pollution of the zinc to molten steel can be avoided;
(2) the dust generated in the smelting process of the converter can be recovered, the dust with high zinc content is subjected to zinc extraction through zinc extraction equipment, so that zinc resources are recycled, the zinc content in the high zinc dust reaches 10%, more than 60% of zinc-containing dust can be obtained through zinc extraction equipment such as a rotary hearth furnace and the like, and the dust can be directly sold, so that considerable benefits are brought;
(3) the low-zinc dust has the zinc content of less than 0.3 percent, can be directly used for blast furnace burdening to replace mineral powder for sintering and then returned to the blast furnace, and saves the waste steel treatment cost of other methods. In the prior art, zinc-containing steel scrap and molten iron are directly added into a converter for smelting, and dust generated by the converter cannot be directly used for sintering because the problem that the zinc load of a blast furnace exceeds the standard at the moment is caused.
When the molten iron and the zinc-containing steel scrap are added into a dephosphorization converter for dephosphorization smelting, zinc in the steel scrap mainly enters a dedusting system to form first high-zinc dust, and trace zinc remains in the semisteel.
When the semi-molten steel is added into a decarburization converter for decarburization smelting, the residual trace zinc in the semi-molten steel enters a primary dedusting system of the converter to form first low-zinc dust, the residual trace zinc in the semi-molten steel enters a secondary dedusting system of the converter to form second high-zinc dust, and the zinc in the molten steel is reduced to be trace.
Preferably, the temperature of the molten iron is 1280-1400 ℃. The temperature of the molten iron is beneficial to stable operation and automatic control of the converter. The temperature of the molten iron is too low, which affects the oxidation process of elements and the temperature rise speed of a molten pool, is not beneficial to slagging and impurity removal, and is easy to splash.
Preferably, the weight ratio of the molten iron to the zinc-containing scrap steel is 85-90: 10 to 15. The weight ratio is weight percentage, and the total amount of the molten iron and the zinc-containing steel scrap is 100%; the arrangement is favorable for cooling and slagging of the molten pool, and if the ratio is more than 90: 10 is not beneficial to cooling the molten pool, so that the ore cold charge is added too much; if less than 85: 15 is not beneficial to melting the scrap steel and influencing slagging.
Preferably, during dephosphorization smelting, the dephosphorization converter is added with blocky lime, oxygen is blown from the top, and nitrogen is blown from the bottom.
The mass fraction of CaO in the massive lime is as follows: more than or equal to 90 wt%, and the granularity of the blocky lime is 10-60 mm. The arrangement is beneficial to effective utilization of slag melting and lime, and is not beneficial to slag melting if the granularity is more than 60 mm; if the diameter is less than 10mm, the lime powder is not beneficial to the effective utilization of lime, and the lime powder can be removed by dust;
the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3/(min.t). This arrangement is advantageous for the progress of dephosphorization. The nitrogen gas supply intensity is as follows: 0.15m3/(min.t)～0.2m3/(min.t). The arrangement is favorable for scrap steel melting and slag steel reaction; if less than 0.15m3/(min.t) is not conducive to scrap melting.
Preferably, the dust removal system in the dephosphorization smelting process and the dust removal system in the decarburization smelting process both adopt dry-method electric dust removal. The parameters of the dry-method electric dust remover are preferably as follows: inlet flue gas amount 175000m3The temperature of inlet flue gas is 180-205 ℃, and the concentration of particulate matters at the inlet of the electric dust collector is less than or equal to 75g/m3The concentration of the particulate matters at the outlet of the electric dust collector is less than or equal to 15mg/m3. Within the parameter range, the dust can be obtained to the maximum extent, and the obtained dust contains zinc, so that the zinc can be collected to the maximum extent.
The method for treating zinc-containing scrap steel by using the converter full-three-strip smelting process is described in detail below by combining examples, comparative examples and experimental data.
Example 1
Executing a converter full-three-removal smelting process flow:
1. adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. Obtaining zinc-containing scrap steel;
3. the method comprises the following steps of charging 37 tons of zinc-containing scrap steel into a dephosphorization converter, charging 290 tons of molten iron into the dephosphorization converter, and carrying out dephosphorization smelting, wherein during dephosphorization smelting, blocky lime is added into the dephosphorization converter, oxygen is blown from the top, and nitrogen is blown from the bottom. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
The produced semisteel water amount is 311 tons, the semisteel water contains 0.0055 percent of zinc, the first dephosphorization ash (namely the first high-zinc dust) is produced for 1.56t, and the first dephosphorization ash contains 11.9 percent of zinc;
4. adding 311 tons of the semi-molten steel into a decarburization converter for decarburization smelting to obtain 301 tons of decarburization molten steel, wherein the molten steel contains 0.0001 percent of zinc, and recovering dust generated in the decarburization smelting to obtain second high-zinc dust and first low-zinc dust; the second high-zinc dust accounts for 0.61 ton, and the second ash contains zinc 14.38%; the first low zinc dust is 2.11 tons, and the zinc content of the first low zinc dust is 0.30 percent.
5. And mixing the first high-zinc dust and the second high-zinc dust, and then recovering zinc to obtain a high-zinc product, wherein the total amount of the first high-zinc dust and the second high-zinc dust is 2.17 tons.
Sintering the first low-zinc dust to obtain blast furnace ingredients for the blast furnace; the zinc content is low, the mixture is directly co-sintered (the zinc content is 0.2 to 0.3 percent), and the direct utilization rate of dust is 49.3 percent.
Example 2
Executing a converter full-three-removal smelting process flow:
1. adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. Obtaining zinc-containing scrap steel;
3. the method comprises the following steps of charging 36 tons of zinc-containing scrap steel into a dephosphorization converter, charging 289 tons of molten iron, and entering the dephosphorization converter for dephosphorization smelting, wherein during dephosphorization smelting, blocky lime is added into the dephosphorization converter, oxygen is blown from the top, and nitrogen is blown from the bottom. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
308 tons of semisteel water are produced, the semisteel water contains 0.0054% of zinc, 1.54t of dephosphorized first ash (first high-zinc dust) is produced, and the zinc content of the dephosphorized first ash is 10.39%;
4. adding 308 tons of the semi-molten steel into a decarburization converter for decarburization smelting to obtain 293 tons of decarburization molten steel, wherein the zinc content of the molten steel is 0.0001%, and recovering dust generated in the decarburization smelting to obtain second high-zinc dust and first low-zinc dust; the second high-zinc dust accounts for 0.60 ton, and the second ash contains zinc 14.64%; the first low zinc dust is 2.05 tons, and the zinc content of the first low zinc dust is 0.30 percent.
5. And mixing the first high-zinc dust and the second high-zinc dust, and then recovering zinc to obtain a high-zinc product, wherein the total amount of the first high-zinc dust and the second high-zinc dust is 2.14 tons.
Sintering the first low-zinc dust to obtain blast furnace ingredients for the blast furnace; the zinc content is low, the mixture is directly co-sintered (the zinc content is 0.2 to 0.3 percent), and the direct utilization rate of dust is 48.9 percent.
Example 3
And executing a converter full-three-removal smelting process flow.
1. Adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. Obtaining zinc-containing scrap steel;
3. the method comprises the following steps of charging zinc-containing scrap steel into a dephosphorization converter by 50 tons, charging 275 tons of molten iron into the dephosphorization converter, and performing dephosphorization smelting in the dephosphorization converter, wherein during dephosphorization smelting, blocky lime is added into the dephosphorization converter, oxygen is blown from the top, and nitrogen is blown from the bottom. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
307 tons of semisteel water are produced, the semisteel water contains 0.0055% of zinc, 1.54 tons of dephosphorized first ash (first high-zinc dust) is produced, and the dephosphorized first ash contains 14.04% of zinc;
4. adding 307 tons of the semi-molten steel into a decarburization converter for decarburization smelting to obtain 292 tons of decarburization molten steel, wherein the molten steel contains 0.0001 percent of zinc, and recovering dust generated in the decarburization smelting to obtain second high-zinc dust and first low-zinc dust; the second high-zinc dust accounts for 0.60 ton, and the second ash contains zinc 14.40%; the first low zinc dust is 2.04 tons, and the zinc content of the first low zinc dust is 0.30 percent.
5. And mixing the first high-zinc dust and the second high-zinc dust, and then recovering zinc to obtain a high-zinc product, wherein the total amount of the first high-zinc dust and the second high-zinc dust is 2.14 tons.
Sintering the first low-zinc dust to obtain blast furnace ingredients for the blast furnace; the zinc content is low, the mixture is directly co-sintered (the zinc content is 0.2 to 0.3 percent), and the direct utilization rate of the dust is 48.74 percent.
Example 4
And executing a converter full-three-removal smelting process flow.
1. Adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. Obtaining zinc-containing scrap steel;
3. 32 tons of zinc-containing waste steel are filled into the dephosphorization converter, 293 tons of molten iron are filled into the dephosphorization converter, and the molten iron enters the dephosphorization converter to be dephosphorized and smelted, and during dephosphorization smelting, blocky lime is added into the dephosphorization converter, oxygen is blown from the top, and nitrogen is blown from the bottom. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
The produced semisteel water amount is 310 tons, the semisteel water contains 0.0050% of zinc, 1.55t of dephosphorizing first ash (first high-zinc dust) is produced, and the zinc content of the dephosphorizing first ash is 10.29%;
4. adding 310 tons of the semi-molten steel into a decarburization converter for decarburization smelting to obtain 300 tons of decarburization molten steel, wherein the molten steel contains 0.0001 percent of zinc, and recovering dust generated in the decarburization smelting to obtain second high-zinc dust and first low-zinc dust; the second high-zinc dust accounts for 0.61 ton, and the second ash contains zinc 14.40%; the first low zinc dust is 2.10 tons, and the zinc content of the first low zinc dust is 0.28 percent.
5. And mixing the first high-zinc dust and the second high-zinc dust, and then recovering zinc to obtain a high-zinc product, wherein the total amount of the first high-zinc dust and the second high-zinc dust is 2.16 tons.
Sintering the first low-zinc dust to obtain blast furnace ingredients for the blast furnace; the zinc content is low, the mixture is directly co-sintered (the zinc content is 0.2 to 0.3 percent), and the direct utilization rate of dust is 49.07 percent.
Comparative example 1
Performing a conventional smelting process (i.e. dephosphorization and decarbonization are carried out in one furnace); 40 tons of scrap steel are loaded into the converter, wherein 20 tons of the scrap steel containing zinc are loaded into the converter, 292 tons of the molten iron are loaded into the converter, and conventional smelting is carried out.
305 tons of molten steel are produced, the zinc content of the molten steel is 0.0016%, 3.97 tons of first ash are produced, and the zinc content of the decarbonized first ash is 4.83%. A second ash of 0.61 ton was produced, containing 14.38% zinc.
The zinc content of the first ash and the zinc content of the second ash are higher, so that zinc extraction equipment can extract zinc, and the total yield of the first ash and the second ash is 4.58 tons, which is higher than two-step steel making.
The direct utilization rate of the dust is 0%.
Comparative example 2
Performing a conventional smelting process (i.e. dephosphorization and decarbonization are carried out in one furnace); 49 tons of scrap steel are charged into the converter, wherein 20 tons of the scrap steel containing zinc are charged into the converter, 286 tons of the molten iron are charged into the converter, and conventional smelting is carried out.
313 tons of molten steel are produced, the zinc content of the molten steel is 0.0021 percent, 4.07 tons of first ash are produced, and the zinc content of the decarbonized first ash is 4.09 percent. A second ash of 0.63 tons is produced, containing 14.06% zinc.
The zinc content of the first ash and the zinc content of the second ash are higher, so that zinc extraction equipment can extract zinc, and the total amount of the first ash and the second ash is 4.7 tons, which is higher than two-step steel making. The direct utilization rate of the dust is 0%.
Comparative example 3
And executing a converter full-three-removal smelting process flow.
1. Adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. Obtaining zinc-containing scrap steel;
3. 81 tons of zinc-containing scrap steel is loaded into the dephosphorization converter, 244 tons of molten iron (the mass percentage of the molten iron to the zinc-containing scrap steel is 75: 25) is loaded into the dephosphorization converter, and the molten iron enters the dephosphorization converter to be dephosphorized and smelted, wherein during the dephosphorization smelting, blocky lime is added into the dephosphorization converter, oxygen is blown from the top, and nitrogen is blown from the bottom. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
The produced semisteel water amount is 280 tons (about 30 tons of scrap steel in the furnace is not melted), the semisteel water contains 0.0073 percent of zinc, 1.40 tons of first dephosphorizing ash (first high-zinc dust) is produced, and the first dephosphorizing ash contains 15.02 percent of zinc;
4. adding 280 tons of the semi-molten steel into a decarburization converter and adding 30 tons of molten iron for decarburization smelting to obtain 300 tons of decarburization molten steel, wherein the zinc content of the molten steel is 0.0001%, and recovering dust generated in the decarburization smelting to obtain second high-zinc dust (decarburization second ash for short) and first low-zinc dust (decarburization first ash for short); 0.58 ton of second high-zinc dust, and 15.17 percent of second dust; the first low-zinc dust contains 2.10 tons of zinc and 0.37 percent of zinc.
5. And mixing the first high-zinc dust and the second high-zinc dust, and then recovering zinc to obtain a high-zinc product, wherein the total amount of the first high-zinc dust and the second high-zinc dust is 2.18 tons.
The zinc content of the first low-zinc dust is 0.37%, the first low-zinc dust exceeds the recovery standard (zinc content is 0.2% -0.3%), and the direct utilization rate of the dust is 0.
Comparative example 4
And executing a converter full-three-removal smelting process flow.
1. Adding iron ore into a blast furnace for melting to obtain molten iron; the temperature of the molten iron is 1280-1400 ℃.
2. No scrap steel is added;
3. and (3) charging 325 tons of molten iron, entering a dephosphorization converter to perform dephosphorization smelting, and adding blocky lime, top blowing oxygen and bottom blowing nitrogen into the dephosphorization converter during dephosphorization smelting. The block lime: CaO is more than or equal to 90 wt%, and the granularity is 30 mm; the oxygen supply intensity is as follows: 0.8m3/(min.t)～2m3V (min.t); the nitrogen gas supply intensity is as follows: 0.2m3/(min.t)；
The produced semisteel water amount is 310 tons, the semisteel water contains 0 percent of zinc, the dephosphorized first ash is produced for 1.55 tons, and the dephosphorized first ash contains 0 percent of zinc;
4. and adding 310 tons of the semi-molten steel into a decarburization converter for decarburization smelting to obtain 300 tons of decarburization molten steel, wherein the zinc content of the molten steel is 0.0001%, and recovering dust generated in the decarburization smelting.
5. The zinc content of the dust is 0 percent, the dust is directly used for sintering, and the utilization rate is 100 percent.
Comparative example 5
The comparative example is that in the prior art, the electric furnace is adopted to recycle the zinc-containing waste steel, the zinc content of the electric furnace dust is generally 10-15%, and the electric furnace dust is directly sent to a zinc refining plant and is not circulated in an iron and steel plant.
Test example 1
Statistics of the zinc content in molten steel, the zinc content in dust, the dust generation amount and the direct dust utilization rate in examples 1 to 4 and comparative examples 1 to 4 are shown in table 1.
TABLE 1
From the data in table 1, it can be seen that:
in comparative example 1, a conventional smelting process was performed, and the zinc content of the decarburization molten steel was 0.0016%, and the direct utilization rate of the first dust generated by decarburization smelting was 0.
In comparative example 2, a conventional smelting process was performed, and the zinc content of the decarburization molten steel was 0.0021%, and the direct utilization rate of the first dust generated by decarburization smelting was 0.
In comparative example 3, the mass ratio of the molten iron to the zinc-containing scrap steel was 75: 25, less than 85: 15, the scrap steel is not easy to melt, and slagging is affected; in addition, the proportion of the zinc-containing scrap is increased, and the zinc content of the decarburization molten steel is not greatly influenced, but the zinc content of the first low-zinc dust generated by decarburization exceeds the standard.
In comparative example 4, the mass ratio of the molten iron to the zinc-containing scrap steel was 100: 0, greater than 90: 10, the dust recovery rate reaches 100%, but the zinc-containing scrap steel is accumulated.
In the embodiments 1-4 of the invention, the pollution of zinc to molten steel can be avoided by utilizing the characteristic of step-by-step smelting of 'three times of decarburization' of the converter, and the zinc content of the decarburized molten steel is 0.0001%; the method has the advantages that zinc in the scrap steel is transferred into the dedusting ash in the smelting process of the dephosphorization converter, and the low-zinc dust generated in the process of smelting the low-zinc semi-molten steel produced by the dephosphorization converter through the decarburization converter is recycled, so that the low-zinc dust can be directly used for blast furnace ingredients to replace mineral powder, the scrap steel treatment cost of other methods is saved, and the direct utilization rate of the dust reaches 48.93-49.30%.
In conclusion, the zinc-containing waste steel is used for 'full-three-decarburization' smelting, so that dust generated by the zinc-containing waste steel smelting is comprehensively utilized, and the problem of reduced benefit caused by the adoption of the zinc-containing waste steel smelting in long-flow (blast furnace and converter) iron and steel enterprises is solved. The low-zinc dust has the zinc content of less than 0.3 percent, can directly replace mineral powder for sintering and then return to a blast furnace, and saves the waste steel treatment cost of other methods. In the prior art, zinc-containing scrap steel and molten iron are directly smelted, and dust generated by smelting cannot be directly sintered, so that the problem that the zinc load of a blast furnace exceeds the standard is caused.
Finally, it should also be 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 (10)
1. A method for treating zinc-containing waste steel by adopting a converter full-three-step smelting process is characterized by comprising the following steps:
adding zinc-containing waste steel into molten iron to carry out dephosphorization converter smelting, and recovering first high-zinc dust through a dust removal system in the dephosphorization smelting process to obtain low-zinc semi-molten steel;
and (3) carrying out decarburization converter smelting on the low-zinc semi-molten steel, and in the decarburization smelting process, recovering the first low-zinc dust and the second high-zinc dust through a dedusting system to obtain decarburized molten steel, thereby finishing the treatment of zinc-containing waste steel.
2. The method for treating the zinc-containing scrap steel by adopting the converter full-three-strip smelting process according to claim 1, wherein the temperature of the molten iron is 1280-1400 ℃.
3. The method for treating the zinc-containing waste steel by adopting the converter full-three-strip smelting process according to claim 1, wherein the weight ratio of the molten iron to the zinc-containing waste steel is 85-90: 10 to 15.
4. The method for treating the zinc-containing waste steel by adopting the converter full-three-decarburization smelting process according to claim 1, wherein the step of adding the zinc-containing waste steel into molten iron for dephosphorization converter smelting specifically comprises the following steps:
adding zinc-containing waste steel into molten iron to perform dephosphorization converter smelting, and adding blocky lime into the dephosphorization converter during the dephosphorization converter smelting process, and blowing oxygen at the top and nitrogen at the bottom.
5. The method for treating the zinc-containing waste steel by adopting the converter full-three-strip smelting process according to claim 4, wherein the mass fraction of CaO in the blocky lime is as follows: more than or equal to 90 wt%, and the granularity of the blocky lime is 10-60 mm.
6. The method for treating the zinc-containing waste steel by adopting the converter full-three-strip smelting process according to claim 4, wherein the supply intensity of oxygen in the top-blown oxygen is as follows: 0.8m3/(min.t)～2m3/(min.t)。
7. The method for treating the zinc-containing waste steel by adopting the converter full-three-strip smelting process according to claim 4, wherein in the bottom blowing nitrogen, the nitrogen supply intensity is as follows: 0.15m3/(min.t)～0.2m3/(min.t)。
8. The method for treating the zinc-containing waste steel by adopting the converter full-three-decarburization smelting process according to claim 1, wherein the dust removal mode of dephosphorization smelting and the dust removal mode of decarburization smelting are both dry electric dust removal, and the dust removal conditions of the dry electric dust removal comprise: inlet flue gas amount 175000m3The temperature of inlet flue gas is 180-205 ℃, and the concentration of particulate matters at the inlet of the electric dust collector is less than or equal to 75g/m3The concentration of the particulate matters at the outlet of the electric dust collector is less than or equal to 15mg/m3。
9. The method for treating the zinc-containing waste steel by adopting the converter full-three-decarburization smelting process according to claim 1, wherein the mass fraction of zinc in the first high-zinc dust is more than 10 percent in dephosphorization smelting.
10. The method for treating the zinc-containing waste steel by adopting the converter full-three-decarburization smelting process according to claim 1, wherein in the decarburization smelting, the mass fraction of zinc in the first low-zinc dust is less than 0.3%, and the mass fraction of zinc in the second high-zinc dust is more than 10%.
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| CN115261547A (en) * | 2021-04-30 | 2022-11-01 | 宝山钢铁股份有限公司 | Method, device, system and storage medium for determining optimal scrap preheating temperature |
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