CN114540617A - Preparation method and application method of redox briquetting of converter fly ash - Google Patents
Preparation method and application method of redox briquetting of converter fly ash Download PDFInfo
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- 239000010881 fly ash Substances 0.000 title claims abstract description 101
- 238000000034 method Methods 0.000 title claims abstract description 71
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 76
- 230000033116 oxidation-reduction process Effects 0.000 claims abstract description 64
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 57
- 239000010959 steel Substances 0.000 claims abstract description 57
- 238000009628 steelmaking Methods 0.000 claims abstract description 49
- 239000008188 pellet Substances 0.000 claims abstract description 43
- 229910052742 iron Inorganic materials 0.000 claims abstract description 37
- 238000004519 manufacturing process Methods 0.000 claims abstract description 36
- 239000002910 solid waste Substances 0.000 claims abstract description 26
- 238000006722 reduction reaction Methods 0.000 claims abstract description 25
- 238000001465 metallisation Methods 0.000 claims abstract description 16
- 239000004615 ingredient Substances 0.000 claims abstract description 11
- 239000002699 waste material Substances 0.000 claims abstract description 6
- 238000000465 moulding Methods 0.000 claims abstract description 4
- 239000002956 ash Substances 0.000 claims description 59
- 239000000853 adhesive Substances 0.000 claims description 21
- 230000001070 adhesive effect Effects 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 230000008569 process Effects 0.000 claims description 19
- 239000000843 powder Substances 0.000 claims description 18
- 238000007885 magnetic separation Methods 0.000 claims description 17
- 230000009467 reduction Effects 0.000 claims description 17
- 239000004484 Briquette Substances 0.000 claims description 16
- 238000005096 rolling process Methods 0.000 claims description 13
- 238000003825 pressing Methods 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 238000005265 energy consumption Methods 0.000 claims description 8
- 238000004064 recycling Methods 0.000 abstract description 15
- 239000000463 material Substances 0.000 description 23
- 239000000428 dust Substances 0.000 description 20
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 20
- 238000005245 sintering Methods 0.000 description 17
- 239000002994 raw material Substances 0.000 description 12
- 239000000440 bentonite Substances 0.000 description 11
- 229910000278 bentonite Inorganic materials 0.000 description 11
- 238000005516 engineering process Methods 0.000 description 11
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 10
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 9
- 238000002156 mixing Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- 239000010802 sludge Substances 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 7
- 239000002893 slag Substances 0.000 description 7
- 239000011449 brick Substances 0.000 description 6
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000005453 pelletization Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 4
- 238000003723 Smelting Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000003034 coal gas Substances 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000000748 compression moulding Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000029087 digestion Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000012369 In process control Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000010965 in-process control Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- GFNGCDBZVSLSFT-UHFFFAOYSA-N titanium vanadium Chemical compound [Ti].[V] GFNGCDBZVSLSFT-UHFFFAOYSA-N 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/248—Binding; Briquetting ; Granulating of metal scrap or alloys
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/2406—Binding; Briquetting ; Granulating pelletizing
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
- C22B1/2413—Binding; Briquetting ; Granulating enduration of pellets
-
- 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)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to a preparation method and an application method of a converter fly ash redox briquetting, and belongs to the technical field of metallurgical solid waste resource recycling. The technical scheme is as follows: replacing waste steel with converter fly ash redox briquettes for steel making production, wherein the converter fly ash redox briquettes are prepared through the procedures of batching, forming and reducing; the converter fly ash and the ingredients are pressed into blocks for molding, then the molded blocks are subjected to oxidation reduction, the strength, the iron content and the metallization rate of the molded blocks are improved, and the converter fly ash oxidation reduction pressed blocks prepared after full reduction reaction directly replace part of scrap steel and are used for converter steelmaking production. The invention improves the strength, iron content and metallization rate of the pellets, directly replaces scrap steel to be applied to converter steelmaking production, reduces production procedures and reduces operation cost.
Description
Technical Field
The invention relates to a preparation method and an application method of a converter fly ash redox briquetting, and belongs to the technical field of metallurgical solid waste resource recycling.
Background
With the development of converter steelmaking production, the steelmaking process is gradually improved, and dry electrostatic dust removal technology, CG method and LT method for short, is mostly adopted in the converter area at present. The dry type system for purifying the converter flue gas and recycling the coal gas is characterized in that a large amount of turbid circulating water is not used for washing the flue gas in the dust removal mode, but a converter coal gas high-temperature high-efficiency heat exchanger or an evaporative cooler, an electrostatic dust collector and a coal gas cooler system are adopted, so that the dry type system plays a positive promoting role in energy conservation and emission reduction of converter steelmaking and realization of negative energy steelmaking in China. The produced solid waste slag of iron and steel, namely the dedusting ash, has the value of resource recycling. The fly ash is a steel-making byproduct, and the best treatment mode is to send the fly ash to a selected burning factory for ball-making and sintering to be applied to steel making. In steel enterprises, more and more people in recent years pay attention to how to reuse smoke dust. The comprehensive utilization of the fly ash realizes the maximization of the recycling value of the fly ash in China. The converter fly ash is dust generated in the converter blowing process, contains a large amount of oxides such as ferric oxide and calcium and has high secondary utilization value, but is difficult to comprehensively utilize due to the characteristics of high generated temperature, high metallization degree, fine granularity, large specific surface area, spontaneous combustion of ferrous oxide, large secondary pollution of dust emission and the like. The production amount of converter fly ash is large, if the converter fly ash can not be effectively utilized, resource waste can be caused, a warehouse, land and a polluted environment can be occupied, even a large-volume solid waste tax is paid, and environmental protection punishment is faced.
At present, three methods are mainly used for utilizing converter fly ash: the direct reduction treatment of converter fly ash in rotary hearth furnace and the addition of sintering material to return to sintering blast furnace for steel making and cold pressing pelletizing for returning to steel making.
1. The application of the direct reduction technology of the rotary hearth furnace; the rotary hearth furnace technology was originally originated in the united states, developed in japan, and introduced by domestic steel works after the technology became mature. The processing raw materials comprise zinc-containing dust, iron oxide scale, iron ore concentrate, vanadium-titanium magnetite, copper slag and the like in steel plants. In 2010, 5 months, the production line of the Shandong sunshine 2 multiplied by 20 million tons of solid waste recycling rotary hearth furnace is built by the integral solution of the process technology provided by the Chinese Steel institute, and is mainly used for solid waste treatment. The production line comprises zinc powder and metallized pellets, the metallization rate of the metallized pellets can reach 75-85%, the total investment is 4 hundred million and more, and the production cost is 1200 yuan/ton. Although the direct reduction technology of the rotary hearth furnace has good reduction effect, the investment of the project is too large, the production and operation cost is too high, and the ton treatment cost is up to 1200 yuan.
2. Returning the converter fly ash to a sintering blast furnace and then to steelmaking utilization; in the past, most of the materials are added into a sintering raw material to return to a sintering rotary blast furnace for steelmaking utilization, and the method for returning converter fly ash as the sintering raw material to the sintering rotary blast furnace for steelmaking utilization has the advantages of long process, low grade and high energy consumption, increases the operation difficulty of sintering and blast furnaces, and is easy to cause sintering faults and influence the service life of a blast furnace lining.
3. Cold pressing pelletizing and returning to the steelmaking utilization method; is obviously superior to the first two methods and is widely applied. Although the flow of the method for returning cold-pressed pelletizing to steelmaking utilization is short, pretreatment such as water adding and digestion and the like on the fly ash, addition of a binder with higher price, drying of finished products and the like are always needed, and the cost is still higher; and the high requirements on processing technology, binder selection and the like are influenced by the fluctuation of dust removal ash, ingredient components, moisture and the like, the pellet strength is difficult to guarantee, and the problems of bin blockage during steel making and addition, rapid melting after charging, poor thermal stability, ash residue and the like are easy to occur. For example: the Chinese patent application 2019110718016 discloses a converter fly ash pressed brick and a preparation and utilization method thereof, which is characterized in that iron-containing solid wastes are mixed, an adhesive is added, the mixture is cold-pressed into balls by a ball press machine and then naturally dried, and then the balls are directly added into the converter production for application. There are problems in that: the strength is low and is only 640N, the fall of the converter is large, and materials collide with each other and are easy to crush. ② the temperature is high, the adhesive is ineffective, the moisture is evaporated rapidly, and the pulverization is easy. Thirdly, the ferric oxide is not reduced, the utilization rate is less than 10 percent, the rest 90 percent of the ferric oxide becomes converter dust, and the dust discharge amount of the converter is increased. The metallic iron content of the solid waste cold-pressed ball is only 0.5 percent; the metallization rate is only 0.85%; the intensity is only 640N. The utilization rate is extremely low, the product quality is influenced, the resources are wasted, the service life of smelting equipment is influenced, and the production running cost is increased.
How to more simply and effectively realize the recycling of converter fly ash has very important significance for realizing the resource recycling of iron and steel enterprises, reducing the production cost and enhancing the sustainable development capability.
Disclosure of Invention
The invention aims to provide a preparation method and an application method of a redox briquetting of converter fly ash, which improve the strength, iron content and metallization rate of pellets, directly replace scrap steel to be applied to converter steelmaking production, reduce production procedures, reduce operation cost and solve the problems in the background art.
The technical scheme of the invention is as follows:
a method for preparing oxidation-reduction briquettes of converter fly ash comprises the working procedures of batching, forming and reducing; briquetting the converter fly ash and the ingredients, and then carrying out redox on the formed briquettes to make the briquettes fully undergo a reduction reaction to prepare a redox briquetting of the converter fly ash; the strength, the iron content and the metallization rate of the oxidation-reduction briquettes of the converter fly ash are improved.
In the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; and (4) the formed briquette enters an oxidation reduction furnace for oxidation reduction.
The high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes.
In the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
The converter dedusting ash comprises converter dedusting coarse ash and converter dedusting fine ash; the other solid wastes comprise solid wastes such as blast furnace dust, converter sludge, gas dust, gas sludge, iron scale, magnetic separation powder and the like.
In the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive (bentonite) and 3 parts of water; the specific data is adjusted according to the user and the actual requirement.
An application method of a converter fly ash redox briquetting is characterized in that the converter fly ash redox briquetting replaces scrap steel for steelmaking production, and the converter fly ash redox briquetting is prepared through the procedures of batching, forming and reducing; the converter fly ash and the ingredients are pressed into blocks for molding, then the molded blocks are subjected to oxidation reduction, the strength, the iron content and the metallization rate of the molded blocks are improved, and the converter fly ash oxidation reduction pressed blocks prepared after full reduction reaction directly replace part of scrap steel and are used for converter steelmaking production.
The converter fly ash redox briquetting is produced by using the following steps in a converter steelmaking process: 4-33 kg of steel per ton.
In the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; and the formed briquettes enter an oxidation reduction furnace for oxidation reduction, and then the formed briquettes replace part of scrap steel in a high-temperature state and are sent into a converter for steelmaking, so that the energy consumption is reduced for the converter steelmaking.
The high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes.
In the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
The converter dedusting ash comprises converter dedusting coarse ash and converter dedusting fine ash; the other solid wastes comprise solid wastes such as blast furnace dust, converter sludge, gas dust, gas sludge, iron scale, magnetic separation powder and the like.
In the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive (bentonite) and 3 parts of water; the specific data is adjusted according to the user and the actual requirement.
The invention has the innovation points that: if the semi-finished pellets (formed briquettes) which are not reduced at high temperature are directly applied to a steel converter, because the temperature of the converter is too high, bentonite which is used as an adhesive can lose efficacy, moisture can be rapidly evaporated, and the pellets can rapidly expand and become powder and are discharged along with smoke, the pellets cannot be directly applied to iron-making and steel-making production at the moment, and can be really applied to production after oxidation reduction. Test results show that after the iron-containing solid waste is pressed into pellets by mixing materials and then is subjected to oxidation reduction treatment, the compressive strength of the pellets can reach more than 3000N, the grade of the total iron is improved by more than 10 percent, the product index completely reaches the technical quality standard of sinter, and the requirements of raw materials for iron-making and steel-making production are met.
Through experimental detection, after the pellets are reduced for 20 minutes at the temperature of 1150 ℃, the total iron content is improved by 14.96 percent; after reducing for 60 minutes in 1250 ℃, the metallization rate is improved to 25.20 percent.
The principle of the oxidation-reduction technology: when the oxidation-reduction equipment reaches a certain temperature, the C and CO in the iron-containing solid waste pellets are formed by the oxidation-reduction briquettes of the converter fly ash2The reaction is carried out to generate CO, and the reaction of the CO and the ferric oxide is the reduction principle.
CO+Fe2O3=Fe3O4+CO2
CO+Fe3O4=FeO+CO2
CO+FeO=Fe+CO2
The invention improves the strength, iron content and metallization rate of the pellets, directly replaces scrap steel to be applied to converter steelmaking production, reduces production procedures and reduces operation cost.
The invention has the beneficial effects that:
the invention a takes the converter fly ash as the main material to be mixed with other solid waste materials for cold pressing and briquetting, then the converter fly ash and the waste steel are added into the converter for recycling. The method has simple process and equipment requirements, simple and easy operation, proper strength of the oxidized and reduced fly ash briquettes, higher iron-containing grade, and convenient storage, transportation and addition, and can replace part of iron ores and waste steel when being added into a converter and also play a certain slagging role; the method not only realizes the effective utilization of waste resources and protects the environment, but also effectively reduces the steelmaking cost, and has good social benefit and economic benefit.
And b, a form that the converter fly ash is subjected to oxidation reduction briquetting and then is added into the converter together with scrap steel for recycling is adopted, compared with direct return sintering utilization and converter utilization after ball pressing, the process, equipment, operation and other aspects are simpler and more convenient, the energy consumption, the cost and the like are lower, and the high-efficiency recycling of resources such as iron, calcium and the like in the fly ash is realized on the premise of lower cost.
c, the usage amount of the converter fly ash redox briquetting is 4-33 kg per ton of steel, and the converter fly ash redox briquetting comprises the following main components in percentage by mass: the total content of converter dedusting coarse ash and fine ash is about 40%, the total content of blast furnace ash is about 25%, and the total content of magnetic separation powder and steel rolling oxide skin is about 30%, so that not only can the batch utilization of converter dedusting ash be realized, but also a new path is provided for the recycling of other iron-containing solid wastes.
d, after the converter fly ash redox briquetting is added into the converter, under the high-temperature action of the added molten iron, CaO generated by dehydrating partial components and active SiO in the slag2And A12O3And the reaction generates anhydrous calcium silicate and anhydrous calcium aluminate with stronger heat resistance, so that the redox briquette has certain high-temperature strength and the thermal stability is improved.
e, adding the fly ash redox briquettes into the converter through a scrap steel bucket, so that the material applicability is strong, and the fly ash redox briquettes of the converter cannot be crushed and pulverized and cannot cause the problem of material blockage; the converter fly ash redox briquetting with light weight and low strength falls into the converter bottom before the scrap steel, so that the direct impact of the scrap steel on the lining of the converter bottom can be effectively reduced; and the addition of the fly ash redox briquetting can improve the alkalinity of the slag at the early stage of converter steelmaking, reduce the solubility of MgO in the slag and reduce the erosion of the furnace lining at the early stage of converter smelting, so the furnace protection cost of the converter can be effectively reduced.
Drawings
FIG. 1 is a schematic view of pellet reduction reaction in the example of the present invention;
FIG. 2 is a schematic process flow diagram of an embodiment of the present invention.
Detailed Description
The invention is further illustrated by the following examples in conjunction with the accompanying drawings.
A method for preparing oxidation-reduction briquettes of converter fly ash comprises the working procedures of batching, forming and reducing; briquetting the converter fly ash and the ingredients, and then carrying out redox on the formed briquettes to make the briquettes fully undergo a reduction reaction to prepare a redox briquetting of the converter fly ash; the strength, the iron content and the metallization rate of the oxidation-reduction briquettes of the converter fly ash are improved.
In the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; and the formed briquette enters an oxidation reduction furnace for oxidation reduction. The high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes.
In the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
The converter dedusting ash comprises converter dedusting coarse ash and converter dedusting fine ash; the other solid wastes comprise solid wastes such as blast furnace dust, converter sludge, gas dust, gas sludge, iron scale, magnetic separation powder and the like.
In the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive (bentonite) and 3 parts of water; the specific data is adjusted according to the user and the actual requirement.
An application method of a converter fly ash redox briquetting is characterized in that the converter fly ash redox briquetting replaces scrap steel for steelmaking production, and the converter fly ash redox briquetting is prepared through the procedures of batching, forming and reducing; the converter fly ash and the ingredients are pressed into blocks for molding, then the molded blocks are subjected to oxidation reduction, the strength, the iron content and the metallization rate of the molded blocks are improved, and the converter fly ash oxidation reduction pressed blocks prepared after full reduction reaction directly replace part of scrap steel and are used for converter steelmaking production.
The converter fly ash redox briquetting is produced by using the following steps in a converter steelmaking process: 4-33 kg of steel per ton.
In the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; and the formed briquettes enter an oxidation reduction furnace for oxidation reduction, and then the formed briquettes replace part of scrap steel in a high-temperature state and are sent into a converter for steelmaking, so that the energy consumption is reduced for the converter steelmaking. The high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes. In the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
The converter dedusting ash comprises converter dedusting coarse ash and converter dedusting fine ash; the other solid wastes comprise solid wastes such as blast furnace dust, converter sludge, gas dust, gas sludge, iron scale, magnetic separation powder and the like.
In the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive (bentonite) and 3 parts of water; the specific data is adjusted according to the user and the actual requirement.
The principle of the oxidation-reduction technology: when the oxidation-reduction equipment reaches a certain temperature, the C and CO in the iron-containing solid waste pellets are formed by the oxidation-reduction briquettes of the converter fly ash2The reaction is carried out to generate CO, and the reaction of the CO and the ferric oxide is the reduction principle.
CO+Fe2O3=Fe3O4+CO2
CO+Fe3O4=FeO+CO2
CO+FeO=Fe+CO2
Reference is made to figure 1.
In the embodiment, the converter fly ash redox briquettes are pellets, and the technical requirements of the ingredients are as follows:
a, determining the total iron content in the pellets, namely, more iron and less slag;
b, determining the carbon content in the pellets, wherein the carbon content is not low enough, and the full reduction of the carbon content and the high influence of the carbon content on the smelting production of the converter cannot be completed;
c, the pellet particle composition is reasonable, and the pellet strength is increased;
d, application of the adhesive, namely increasing the strength and assisting reduction;
and e, determining the moisture of the pellets, namely, the moisture is too low to influence wet grinding, the moisture is too high, and the increase time is long.
In the embodiment of the invention, the preparation method of the oxidation-reduction briquetting of converter fly ash comprises the following steps:
step one, preparing materials: throwing converter dedusting coarse ash, converter dedusting fine ash, blast furnace ash, steel slag magnetic separation powder, steel rolling oxide skin and adhesive (bentonite) into a tank bin;
step two, batching: weighing the materials according to the batching scheme, and then feeding the materials into a mixer through a belt conveyor; the weight portion ratio of each component is as follows: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive (bentonite) and 3 parts of water;
step three, mixing materials: stirring and mixing the materials by using a mixer, slowly adding water and stirring in a process control metering manner, uniformly stirring, discharging and conveying to a middle bin by a belt;
step four, feeding the components in the material into a next wet mill in a middle bin, and feeding the components into a ball press through a belt conveyor;
step five, compression molding: discharging the blank from a wet mill, feeding the blank into a stamping system of a brick press, and demolding after press forming to obtain a converter fly ash press ball blank;
step six: the converter fly ash is pressed into blocks for oxidation reduction; and (3) after the converter dedusting ash brick blank is taken off the line, the converter dedusting ash brick blank enters an oxidation reduction furnace, oxidation reduction is carried out through timing and temperature setting, and then converter dedusting ash briquettes are sent into the converter for steelmaking at high temperature, so that the energy consumption is reduced for the converter steelmaking.
In the embodiment of the invention, the application method of the oxidation-reduction briquetting of the converter fly ash is a method for recycling the oxidation-reduction briquetting of the converter fly ash and the scrap steel together, and the oxidation-reduction briquetting of the converter fly ash and the scrap steel replace part of the scrap steel.
The method comprises the following steps:
the method comprises the following steps: preparing materials: sending the fly ash redox briquettes into a scrap steel room to be stacked, and taking the small scrap steel as a spare, wherein the usage amount of the fly ash redox briquettes in the furnace is controlled to be below 40% of the total weight of the scrap steel and the fly ash redox briquettes; the usage amount of the fly ash redox briquetting is as follows: 4-33 kg of ton steel;
step two: charging: firstly, filling scrap steel into the middle rear part and the bottom layer of the scrap steel bucket, and then filling converter fly ash oxidation-reduction briquettes into the residual space of the scrap steel bucket;
step three: adding: and D, before adding molten iron into the converter, adding the scrap steel loaded in the step two and the oxidation-reduction briquettes of the converter fly ash into the converter at one time.
In the embodiment, the fly ash redox briquette using converter fly ash as a main raw material is prepared from the following raw materials in parts by weight: converter dedusting coarse ash, converter dedusting fine ash, blast furnace ash, magnetic separation powder, steel rolling oxide skin, adhesive (bentonite) and water. The ingredients of the raw materials used are shown in table 1 below.
Table 1 example 1 raw material composition (wt%)
| Raw materials | CaO | SiO2 | MgO | SO3 | Al2O3 | TFe | H2O |
| Converter fly ash | 6.95 | 2.60 | 1.33 | 0.10 | 0.38 | 53.91 | 3.50 |
| Blast furnace dust | 7.62 | 3.10 | 1.46 | 0.13 | 0.87 | 45.77 | 0.67 |
| Magnetic separation powder | 32.75 | 13.86 | 14.01 | 3.05 | 42.65 | ||
| Steel rolling oxide skin | 74.69 | - | |||||
| Bentonite clay | 5.76 |
The preparation method of the oxidation-reduction briquetting of converter fly ash comprises the following steps:
firstly, throwing converter dedusting coarse ash, converter dedusting fine ash, blast furnace ash, magnetic separation powder, steel rolling oxide skin and adhesive (bentonite) into a tank bin;
step two, batching: weighing the materials according to the batching scheme, then conveying the materials into a mixing bin through a belt conveyor, and then conveying the materials into a mixer for mixing; the weight parts of the materials are respectively as follows: converter dedusting ash 45, converter dedusting fine ash 15, blast furnace ash 25, magnetic separation powder 18%, steel rolling oxide skin 27%, adhesive (bentonite) 5 and water 3;
step three, mixing materials: and (3) stirring and mixing the materials by using a mixer, wherein the mixing reaches 1/500 standard. Adding water and stirring slowly in process control metering, discharging after stirring uniformly and conveying to a middle bin by a belt;
step four, feeding the components in the material into a next wet mill in a middle bin, and feeding the components into a ball press through a belt conveyor;
step five, compression molding: discharging the blank from a wet mill, feeding the blank into a stamping system of a brick press, and demolding after press forming to obtain a converter fly ash press ball blank;
step six, pressing the converter fly ash into blocks in an oxidation reduction mode: and the converter dedusting ash brick blank enters an oxidation reduction furnace after being taken off the line, oxidation reduction is carried out at the fixed temperature of 1000-1300 ℃, and then converter dedusting ash briquettes are sent into the converter for steelmaking at high temperature, so that the energy consumption is reduced for the converter steelmaking.
Comparison table for chemical composition change before and after pellet oxidation reduction
| Chemical composition | All iron | Metallic iron | Ferrous oxide | Ferric oxide | Carbon (C) | Metallization rate |
| Before reduction | 58.64 | 0.5 | - | 63.92 | 4.4 | 0.85 |
| After reduction | 73.60 | 18.5 | 36.3 | - | 0 | 25.2 |
Through experimental detection, after the pellets are reduced for 20 minutes at the temperature of 1150 ℃, the total iron content is improved by 14.96 percent; after reducing for 60 minutes in 1250 ℃, the metallization rate is improved to 25.20 percent.
The high-quality pellets are very popular high-quality materials in iron-making and steel-making production.
Test results show that after the converter fly ash is pressed into balls through mixing and then is subjected to oxidation reduction treatment, the compression strength of the pressed blocks can reach more than 3000N, the total iron grade is improved by more than 10 percent, the product index completely reaches the technical quality standard of sinter, and the requirements of raw materials for iron-making and steel-making production are met.
In the prior art, most of the raw materials for sintering are added and returned to a blast furnace for sintering and then to steel-making for utilization, and along with the development of the technology, a plurality of enterprises begin to adopt cold pressing pelletizing and return to steel-making for utilization. The method for adding the sintering raw materials to return to the sintering rotary blast furnace and then to utilize the steel-making has long process, low grade and large energy consumption, increases the operation difficulty of the sintering and blast furnace, and is easy to cause sintering faults and influence the service life of the blast furnace lining; although the flow of the method for returning cold-pressed pelletizing to steelmaking utilization is short, pretreatment such as water adding and digestion and the like on the fly ash, addition of a binder with higher price, drying of finished products and the like are always needed, and the cost is still higher; and the high requirements on processing technology, binder selection and the like are influenced by the fluctuation of dust removal ash, ingredient components, moisture and the like, the pellet strength is difficult to guarantee, and the problems of bin blockage during steel making and addition, rapid melting after charging, poor thermal stability, ash residue and the like are easy to occur. Therefore, how to more simply and effectively realize the recycling of the converter fly ash has very important significance for realizing the resource recycling, reducing the production cost and enhancing the sustainable development capability of the iron and steel enterprises.
Claims (8)
1. A preparation method of oxidation-reduction briquettes for converter fly ash is characterized by comprising the following steps: comprises the working procedures of batching, forming and reducing; briquetting the converter fly ash and the ingredients, and then carrying out redox on the formed briquettes to make the briquettes fully undergo a reduction reaction to prepare a redox briquetting of the converter fly ash; the strength, the iron content and the metallization rate of the oxidation-reduction briquettes of the converter fly ash are improved.
2. The method for preparing redox briquettes made of converter fly ash according to claim 1, wherein the method comprises the following steps: in the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; the formed briquette enters an oxidation reduction furnace for oxidation reduction; the high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes.
3. The method for preparing a converter fly ash redox compact according to claim 1 or 2, characterized in that: in the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
4. The method for preparing a converter fly ash redox compact according to claim 1 or 2, characterized in that: in the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive and 3 parts of water.
5. An application method of oxidation-reduction briquettes of converter fly ash is characterized in that: replacing waste steel with converter fly ash redox briquettes for steel making production, wherein the converter fly ash redox briquettes are prepared through the procedures of batching, forming and reducing; the converter fly ash and the ingredients are pressed into blocks for molding, then the molded blocks are subjected to oxidation reduction, the strength, the iron content and the metallization rate of the molded blocks are improved, and the converter fly ash oxidation reduction pressed blocks prepared after full reduction reaction directly replace part of scrap steel and are used for converter steelmaking production.
6. The method for applying the converter fly ash redox briquette according to claim 5, wherein the method comprises the following steps: the converter fly ash redox briquetting is produced by using the following steps in a converter steelmaking process: 4-33 kg of steel per ton.
7. The method for applying the converter fly ash redox briquette according to claim 6, wherein the method comprises the following steps: in the reduction procedure, the formed briquette is subjected to high-temperature oxidation reduction; the formed briquette enters an oxidation reduction furnace for oxidation reduction, and then the formed briquette replaces part of scrap steel in a high-temperature state and is sent into a converter for steelmaking, so that the energy consumption is reduced for the converter steelmaking; the high-temperature oxidation reduction is carried out at the temperature of 1000-1300 ℃ for 20-60 minutes; in the burdening and forming process, the formed briquettes are pellets, converter fly ash and other solid wastes are mixed together, and then adhesive and water are added to the mixture to form the pellets through cold pressing of a pellet production line.
8. The method for applying the converter fly ash redox briquette according to claim 7, wherein the method comprises the following steps: in the burdening process, the components are as follows in parts by mass: 30-50 parts of converter dedusting coarse ash, 10-20 parts of converter dedusting fine ash, 20-40 parts of blast furnace ash, 15-20 parts of magnetic separation powder, 20-30 parts of steel rolling oxide skin, 5 parts of adhesive and 3 parts of water.
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