CN109055731B - Dust granulation process and iron ore sintering process - Google Patents

Dust granulation process and iron ore sintering process Download PDF

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Publication number
CN109055731B
CN109055731B CN201811156211.9A CN201811156211A CN109055731B CN 109055731 B CN109055731 B CN 109055731B CN 201811156211 A CN201811156211 A CN 201811156211A CN 109055731 B CN109055731 B CN 109055731B
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dust
grinding
sintering
ash
mixing
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CN109055731A (en
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李康
孙醒波
周志安
李继淦
杨正伟
李洁
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Zhongye Changtian International Engineering Co Ltd
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Zhongye Changtian International Engineering Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24Binding; Briquetting ; Granulating
    • C22B1/2406Binding; Briquetting ; Granulating pelletizing
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16Sintering; Agglomerating
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00Preliminary treatment of ores or scrap
    • C22B1/14Agglomerating; Briquetting; Binding; Granulating
    • C22B1/24Binding; Briquetting ; Granulating
    • C22B1/242Binding; Briquetting ; Granulating with binders
    • C22B1/243Binding; Briquetting ; Granulating with binders inorganic

Abstract

A dust granulation process, the process comprising the steps of: 1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials; 2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient; 3) mixing: mixing the ground dust ingredients to obtain a dust mixture; 4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture; 5) pelletizing: pelletizing the wet and ground dust mixture to obtain the green dust balls. The invention also provides an iron ore sintering process, wherein the prepared dust green pellets are added into the uniformly mixed ore obtained by mixing the sintering mixture twice and enter the sintering machine together for sintering. The process of the invention can effectively improve the air permeability of the sinter bed, improve the quality of the sintered mineral products, avoid resource waste and reduce environmental pollution.

Description

Dust granulation process and iron ore sintering process
Technical Field
The invention relates to the field of sintering in iron and steel plants, in particular to a dust pelletizing process and an iron ore sintering process, and mainly solves the problems of environmental pollution and resource waste caused by dust generated in a blast furnace and a sintering process in the iron and steel plants, and low utilization rate and poor utilization effect of the existing dust.
Background
The main development direction of the steel industry is environment-friendly, green and ecological and efficient comprehensive utilization of resources. In a steel plant, a blast furnace and a sintering process generate a large amount of dust, and particularly, the proportion of the dust generated in the sintering process is the largest. However, the generated dust often causes environmental pollution in a production area, and if the dust is discarded at will, the dust not only causes environmental pollution, but also causes resource waste.
At present, the treatment mode of the dust is simpler in domestic steel and iron plants, the dust generated in the sintering process and the primary ash of a blast furnace can be used as the ingredients of sintering raw materials, and the rest dust is basically discarded. The existing specific utilization mode is that the primary ash of a blast furnace and dust removal powder inside sintering are mixed with sintering and blending ores to participate in blending, and the blast furnace tapping field ash and the raw material ash are directly humidified and then mixed; in general, the blast furnace dust recycled by the sintering process and the sintering internal dust are not subjected to corresponding pretreatment and processing, but are added at different positions. And other dusts such as miscellaneous mineral powder generated in the process of raw material treatment, various dusts generated in the processes of coking and blast furnace smelting, converter dust, steel slag and mud cake generated in the process of steelmaking, iron scale generated in the process of steel rolling, activated sludge generated by chemical companies and the like. The dust is basically discarded, the dust and byproducts usually contain beneficial components such as high Fe, CaO, MgO, fixed carbon and the like, can be used as substitutes of sintering raw fuel, and wastes limited resources and pollutes the environment if being discarded. In addition, if these dusts are directly added to the sintering raw material to be mixed, since there is a certain difference in properties of such dusts as compared with the new sintering raw material, the direct addition affects the quality of the sintered ore.
The prior art treatment methods for dust treatment have a great problem. Considering that the dust inside the blast furnace and the sintering has fine particle size, especially the dust of the blast furnace (including first and second ashes of the blast furnace, the ash of a cast house and the ash of a raw material) has extremely fine particle size, wherein the part with the particle size of less than 0.125mm is up to more than 60.5 percent, and the average particle size is only 0.2mm, if the dust is simply and directly added into the raw material for sintering, the dust has negative influence on the sintering productivity index. In addition, the amount and components of the generated blast furnace dust and the sintered dust change along with the change of production and the change of material structure, which brings certain influence on the stability of sintering production.
Therefore, the actual utilization rate of the dust generated by blast furnaces and sintering is low so far, which not only wastes limited resources, but also pollutes the environment. With increasing attention to environmental pollution and comprehensive cost, the realization of the sealing and relatively centralized efficient treatment of dust in blast furnaces and sintering furnaces is a future development trend.
In order to better solve the problems caused by various dusts generated in steel plants, the dusts generated in the sintering and blast furnace processes need to be sealed, relatively intensively and efficiently treated, the environmental pollution and the comprehensive cost are reduced, and finally higher economic benefit is realized by researching the pelletizing and roasting characteristics of the dusts and the behaviors of the dusts in the sintering process.
Disclosure of Invention
In view of the above-mentioned drawbacks and disadvantages of the prior art, it is an object of the present invention to provide a dust granulation process. The process mixes and granulates various dusts and byproducts generated in the blast furnace area and the sintering area to obtain dust green balls, and the dust is sealed and efficiently treated in a centralized way, so that the resource waste is avoided, and the environmental pollution and the comprehensive cost are reduced.
The invention also provides an iron ore sintering process based on dust granulation, the process arranges the prepared dust green pellets and the mixed ore obtained by mixing the sintering mixture in the existing sintering process on a sintering machine trolley together for sintering, effectively utilizes beneficial components such as Fe, CaO, MgO, fixed carbon and the like in the dust, simultaneously independently granulates the dust into balls, and then mixes the balls with other granulated sintering raw materials, the dust green pellets with larger particle size are mainly concentrated at the lower part of a sintering material layer, and the sintering material green pellets with smaller particle size obtained after mixing are covered on the dust green pellets, so the dust green pellets play a good skeleton role, effectively improve the air permeability of the sintering material layer, improve the quality of iron ore sintering products and simultaneously realize high economic benefit.
According to a first embodiment of the invention, there is provided a dust granulation process:
a dust granulation process, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet and ground dust mixture to obtain the green dust balls.
In the present invention, the green dust balls obtained in step 5) have a particle size of 8 to 16mm, preferably 9 to 15mm, more preferably 10 to 14 mm.
Preferably, the moisture content of the dust green pellets obtained in step 5) is 9 to 13%, preferably 9.6 to 12.5%, more preferably 10 to 12%.
In the invention, various dusts generated in the blast furnace and/or sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash.
Preferably, in the step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail fly ash, sintering finished product fly ash, sintering ingredient fly ash, sintering main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; preferably 10 to 15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
In the present invention, the alkalinity regulator in step 1) is quicklime. Preferably, the amount of quicklime added is less than 2%, preferably less than 1%. Preferably, the quicklime has a particle size of 0 to 5mm, preferably 0.5 to 3 mm.
In the invention, the dust ingredient added with the alkalinity regulator is ground in the step 2), and the granularity of the dust is ground to-200 meshes which is more than 70 percent, preferably more than 75 percent, and more preferably more than 80 percent.
In the present invention, water is added to the dust blend after the grinding in step 3) when the dust blend is mixed. Preferably, the amount of water added is 5 to 8%, preferably 6 to 7%.
Preferably, the mixing time in step 3) is 30 to 60s, preferably 35 to 50 s.
In the invention, the binder in the step 4) is bentonite. Preferably, the bentonite is ground before being added to the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is more than 80%, preferably more than 90%. Preferably, the amount of bentonite added is 0.5 to 6%, preferably 1 to 4%.
Preferably, the time for the mixed grinding in the step 4) is 1-15min, preferably 2.5-10 min.
In the invention, water is added to the dust mixture after the wet grinding in the step 5) when the granulation is carried out on the dust mixture.
Preferably, the time for pelletizing in step 5) is 8-16min, preferably 10-15 min.
Preferably, the grinding in the step 2) adopts a high-pressure roller mill.
Preferably, an intensive mixer, preferably a vertical intensive mixer, is used for the mixing in step 3).
Preferably, the mixing and grinding in the step 4) adopts a wet grinding machine.
According to a second embodiment of the present invention, there is provided an iron ore sintering process:
a process for sintering iron ore, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
6) and (3) sintering: adding the dust green balls obtained in the step 5) into the uniformly mixed ore obtained after the sintering mixture is secondarily mixed, and sintering the uniformly mixed ore in a sintering machine.
In the present invention, the particle size distribution of the dust green pellets obtained in step 5) is 8 to 16mm, preferably 9 to 15mm, more preferably 10 to 14 mm.
Preferably, the moisture content of the dust green pellets obtained in step 5) is 9 to 13%, preferably 9.6 to 12.5%, more preferably 10 to 12%.
In the invention, various dusts generated in the blast furnace and/or sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash.
Preferably, in the step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail fly ash, sintering finished product fly ash, sintering ingredient fly ash, sintering main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; preferably 10 to 15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
In the present invention, the alkalinity regulator in step 1) is quicklime. Preferably, the amount of quicklime added is less than 2%, preferably less than 1%. Preferably, the quicklime has a particle size of 0 to 5mm, preferably 0.5 to 3 mm.
In the invention, the dust ingredient added with the alkalinity regulator is ground in the step 2), and the granularity of the dust is ground to-200 meshes which is more than 70 percent, preferably more than 75 percent, and more preferably more than 80 percent.
In the present invention, water is added to the dust blend after the grinding in step 3) when the dust blend is mixed. Preferably, the amount of water added is 5 to 8%, preferably 6 to 7%.
Preferably, the mixing time in step 3) is 30 to 60s, preferably 35 to 50 s.
In the invention, the binder in the step 4) is bentonite. Preferably, the bentonite is ground before being added to the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is more than 80%, preferably more than 90%. Preferably, the amount of bentonite added is 0.5 to 6%, preferably 1 to 4%.
Preferably, the time for the mixed grinding in the step 4) is 1-15min, preferably 2.5-10 min.
In the invention, water is added to the dust mixture after the wet grinding in the step 5) when the granulation is carried out on the dust mixture.
Preferably, the time for pelletizing in step 5) is 8-16min, preferably 10-15 min.
Preferably, the grinding in the step 2) adopts a high-pressure roller mill.
Preferably, an intensive mixer, preferably a vertical intensive mixer, is used for the mixing in step 3).
Preferably, the mixing and grinding in the step 4) adopts a wet grinding machine.
The dust granulation process in the invention is different from the prior dust treatment or utilization mode. In the invention, various dusts generated in the blast furnace and the sintering process do not participate in the batching and pelletizing of the sintering mixture in the existing sintering process, the dust is subjected to special steps of batching, grinding, mixing grinding and pelletizing to prepare the dust green pellets with larger particle size (the particle size distribution is 8-16mm, preferably 9-15mm, and more preferably 10-14mm), and the dust green pellets and the uniformly mixed ore obtained by mixing the sintering mixture in the existing sintering process are fed into a sintering machine for sintering. Generally, the particle size of green sintered pellets obtained by mixing the sintering mixture in the conventional sintering process is small and is 4-5 mm. The dust green balls with larger grain sizes and the sintering material green balls with smaller grain sizes are arranged on a sintering machine trolley together through a sintering machine distributing device, the existing sintering machine distributing device adopts a ball roller distributing device, and the ball roller distributing device generates natural segregation effect on the grain sizes of the mixture, so that the mixture is distributed to a sintering machine through the ball roller distributing device, the mixture can be layered according to the grain sizes, the grain sizes of the green balls from the upper part to the lower part of a sintering material layer are gradually increased, namely the dust green balls with larger grain sizes are mainly concentrated on the lower part of the sintering material layer, and the sintering material green balls with smaller grain sizes cover the dust green balls. Therefore, the dust green balls with larger grain diameters positioned at the lower part of the sinter bed play a good skeleton role in the sinter bed on the whole sintering pallet, thereby improving the air permeability of the sinter bed and effectively improving the quality of sinter.
According to the technical scheme, the dust is independently granulated, and the particle size of the prepared green dust balls is far larger than that of the pellets prepared from the sintering mixture. The particle size of the prepared dust green ball is larger than 8mm, and the particle size of the sintering mixture after the two-mixing is 4-5 mm. Because the material composition of the collected dust is different from that of a new sintering raw material, if the collected dust is directly discarded, limited resources are wasted, and the environment is polluted; however, if the collected dust is directly added to a new sintering material and subjected to two-stage mixing granulation with the new sintering material, the dust enters the sintering process as a part of the granulated sintering material, and the quality of the whole sintered ore is affected due to the difference in the material composition in the dust. In the prior art, sintering raw materials are added into dust, and then granulation is carried out through two-mixing to obtain a sintering material for sintering, and the quality of sintered ore after sintering is influenced due to the existence of the dust. The invention adopts the following process: independently granulating the dust to prepare a sintering material with the particle size of more than 8mm, directly adding the sintering material into the two-mixed sintering material, and not participating in the mixing and granulating process of new sintering raw materials, wherein the new sintering raw materials are also prepared according to the original process to prepare the sintering material with the particle size of 4-5 mm; and then distributing the raw dust balls by a sintered material distributing device, wherein the raw dust balls are naturally concentrated on a blanking layer of the sintering machine under the segregation effect of the distributing device because the particle size of the raw dust balls is different from that of the sintered material prepared from the new sintering raw material, and the sintered material prepared from the new sintering raw material is naturally concentrated on an upper material layer of the sintering machine, so that the raw dust balls play a skeleton role in the whole material layer of the sintering machine, and the air permeability of the material layer of the sintering machine is improved. The collected dust was granulated separately: firstly, resources are utilized, and the pollution to the environment is reduced; secondly, the granulation and sintering effects of new sintering raw materials are not influenced; thirdly, the arrangement of the material layer of the sintering machine is improved, and the ventilation property of the material layer is improved by the dust green ball playing the role of the framework.
Generally, the air permeability of the sinter bed is good and bad, which directly affects the whole sintering process and the quality of the sinter. The sintering plants at home and abroad pay great attention to the improvement of the air permeability of the sinter bedProvided is a method for producing a novel compound. In the invention, the dust green ball prepared by the dust granulation process is used for sintering, so that a new sintering process is formed. In the new sintering process, the dust green ball is more concentrated on the lower part of the sinter bed during material distribution due to larger grain diameter, so that the function of a skeleton is achieved, and the air permeability of the sinter bed is effectively improved. Firstly, the air permeability of a sinter bed is improved, the resistance of a fan is reduced, the effective air quantity passing through the sinter bed is increased, the vertical sintering speed is increased, and the sintering is strengthened; meanwhile, the air permeability of the sinter bed is improved, the thickness of the sinter bed can be increased, and the sintering of a thick sinter bed is favorable for calcium ferrite and Fe2O3The generation of mineral phases can reduce the FeO content and improve the strength of sintered ore; moreover, the sinter bed has the function of automatic heat storage, the sintering solid fuel consumption can be reduced by increasing the thickness of the bed, resources are saved, the solid fuel consumption is reduced, and SOx, NOx and CO in the sintering process are reduced from the source2Generating; in addition, the air permeability of the sinter bed is improved, the negative pressure in the sintering machine is reduced, and the blown air can fully contact with the sulfide, so that the sintering roasting reaction is strengthened, and the desulfurization speed is accelerated. In addition, if the permeability of the sinter bed is poor, the local temperature of the sinter bed is likely to rise sharply, and the content of NOx is increased rapidly, that is, the permeability of the sinter bed is improved, and the generation of NOx is reduced from the source.
In the present invention, the dust is granulated separately for the purpose: firstly, preparing dust green balls with larger particle sizes, and playing a skeleton role in a material layer of a sintering machine; secondly, if the granulated green dust balls are added into the mixer or a mixing process (such as secondary mixing) again, the particle size of the green dust balls with larger particle size is reduced due to grinding action in the mixer, so that the purpose of skeleton function cannot be achieved; and thirdly, if the granulated green dust balls are added into the mixer or a mixing process (such as secondary mixing) again, the green dust balls are mixed with other sintering materials too uniformly, and the sintering performance of the sintering materials prepared from new sintering raw materials is influenced. By adopting the process, the prepared dust green balls with larger particle sizes are concentrated on the blanking layer of the sintering machine when the sintering material is distributed, after sintering, the sintering ore (the sintering ore obtained by sintering material prepared by new sintering raw material) of the upper material layer of the sintering machine can be distinguished from the sintering ore (the sintering ore obtained by dust green balls) of the lower material layer according to the specific application of the sintering ore, and the sintering ores with different qualities are used for different applications; not only the quality of the original sinter is not reduced, but also the air permeability of the sinter bed is improved and the sintering performance is improved due to the distribution of the dust green pellets, and the quality of the sinter obtained by the sinter prepared by new sintering raw materials can be improved.
In addition, the dust is independently granulated, and the moisture content of the obtained green dust balls is particularly critical.
The test scheme and the fixed test conditions were: the iron-containing dust and the bentonite are mixed uniformly, and then the mixture is pelletized on a disk pelletizer with the diameter of 1 meter. The raw material moisture is 3.5%, the green pellet moisture is about 11.7%, the bentonite dosage is 2.0%, the pelletizing time is 12 minutes, the pellet particle size is 8-15mm, the influence of the green pellet moisture on the pellet output quality index is inspected, and the obtained main test results are shown in the table.
Influence of green ball moisture on ball quality index
In the present invention, the moisture content of the dust green pellets produced is 9 to 13%, preferably 9.6 to 12.5%, more preferably 10 to 12%, for example 11.7%. The moisture content is based on the total weight of the green dust ball. The invention adopts dust to granulate separately, and the diameter of the prepared dust green ball is larger, which is different from the moisture content in the existing granulation adopting sintering raw materials, the moisture content in the existing granulation adopting sintering raw materials is 6-7%, and the strength of the prepared granule is not high. As can be seen from the above table, the green dust ball of the present invention has increased moisture content, and significantly improved drop strength and compressive strength. Meanwhile, the moisture content in the dust green ball is correspondingly controlled, and the overall performance of the dust green ball is ensured; the cracking temperature is prevented from being too low, the sintering of the sintering material is prevented from being influenced, and the quality of the sintering ore is ensured.
In the invention, the various dusts generated in the blast furnace and/or sintering process in the step 1) mainly refer to fine dry dusts, including but not limited to secondary blast furnace dust, blast furnace cast house dust, blast furnace raw material dust, sintering machine tail fly ash, sintering finished product fly ash, sintering ingredient fly ash, sintering main electric fly ash, steelmaking molten steel refining fly ash, and the steelmaking molten steel refining fly ash includes first and second steelmaking molten steel refining fly ash. Wherein, the weight ratio of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail fly ash, sintering finished product fly ash, sintering batching fly ash, sintering main electric fly ash, steelmaking molten steel refining fly ash is preferably 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; preferably 10 to 15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2, e.g. 12: 8: 8: 36: 18: 17: 1: 1. due to the fact that the physical and chemical properties of the dust are different to a certain extent, under the proportion, the pelletizing effect of the dust is better, the physical and chemical properties of the obtained green dust balls are more stable, and the maximum utilization of the dust is achieved.
The green dust balls obtained by the dust granulation process of the invention are finally used as a substitute of sintering raw fuel to participate in sintering, therefore, the alkalinity regulator in the invention is preferably quicklime which is used as a flux raw material, and part of the quicklime participates in the proportioning of the dust, so that the dosage of the flux in a sintering proportioning chamber can be reduced, and the alkalinity of the green dust balls can be improved. In the present invention, the quicklime has a particle size of 0 to 5mm, preferably 0.5 to 3 mm. Controlling the particle size of the quicklime to ensure that the particle size of the prepared dust green ball is more than 8 mm; if the particle size of the alkalinity regulator is too large, the granulation of dust is not facilitated, and the particle size of the green dust balls is too small, so that the green dust balls are not conducive to playing a skeleton role in a sinter layer.
In the present invention, the pulverizing step of step 2) employs a high pressure roller mill to mill the dust to a dust particle size of-200 mesh (less than 200 mesh) with a dust proportion of more than 70% (preferably more than 75%, more preferably more than 80%). The purpose of the grinding step is mainly to grind various dusts generated in the blast furnace and the sintering process to a certain granularity so as to increase the balling property of the dusts. If the pelletizing property of each dust is poor, the subsequent pelletizing and pelletizing process is affected, dust green balls with larger particle sizes cannot be generated, the particle sizes of the dust green balls are not enough, and the cloth cannot play a skeleton role at the lower part of a sinter bed, so that the air permeability of the sinter bed is affected. The invention starts from the sources of various raw materials, and controls the particle sizes of the various raw materials, thereby ensuring the particle size of the finally prepared dust green ball.
In the present invention, an intensive mixer (preferably a vertical intensive mixer, for example, a R24 vertical intensive mixer) is used in the mixing step of step 3), and water is added to the mixer while mixing. The working principle of the intensive mixer is that materials move oppositely to permeate each other by means of the opposite movement between the stirring paddle and the mixing barrel, so that the aim of fully mixing is fulfilled; the adoption of the intensive mixer can save electric energy, reduce the using amount of the binder, enhance the green ball strength and improve the uniformity of materials. Therefore, the mixing step is mainly to enable the dust to mutually permeate through the opposite movement, so that the purpose of fully mixing the dust is achieved, the balling property of the dust is improved, and the strength of the subsequent green dust balls is improved.
In the invention, the step of mixing and grinding in the step 4) adopts a moistening and grinding machine. Generally, the longer the wet grinding time, the higher the drop strength and compressive strength of the finally produced green dust balls, but the wet grinding time cannot be too long, the too long time, and the burst temperature of the green dust balls will be lowered, so the wet grinding time is controlled to be 1-15min (preferably 2.5-10min) in the present invention. The step of mixing and grinding also adds a binder (preferably bentonite), namely the step improves the fineness and the specific surface area of each dust and the binder, improves the balling performance of the dust and further mixes each dust and the binder uniformly through the wet grinding. Before the binder is added into the dust mixture, the particle size of the binder is ground to-325 meshes and more than 80 percent (preferably more than 90 percent), and the grinding of the binder is also used for increasing the fineness and the specific surface area of the binder, so that the binder and the dust can be better mixed uniformly, the balling property of the dust in the subsequent pelletizing and pelletizing step is enhanced, and the particle size of the finally prepared green dust balls is ensured.
In the invention, the pelletizing step of the step 5) adopts a pelletizer to pelletize. And water is added during pelletizing, so that the wet and ground dust mixture is pelletized on a pelletizer under the condition of spraying water. Generally, the green pellet strength is obviously improved along with the prolongation of the pelletizing time, but the bursting temperature of the green pellet is lower than 600 ℃ after the pelletizing time exceeds 16min, so the pelletizing time is controlled to be 8-16min (preferably 10-15min) in the invention. The falling strength and compressive strength of the green pellets can be improved along with the increase of moisture of the green pellets; however, since the green pellet has a moisture content of more than 13% and the strength begins to decrease, the moisture content of the dust green pellet produced in the present invention is 9 to 13% (preferably 9.6 to 12.5%, more preferably 10 to 12%, for example, 11.7%). In the invention, the particle size distribution of the dust green balls manufactured by the pelletizer is 8-16mm (preferably 9-15mm, more preferably 10-14mm), the larger the particle size of the dust green balls is, the more obvious the segregation distribution on the sintering pallet is, the better the air permeability in the sintering process is, but the particle size of the dust green balls cannot be too large, the falling strength of the green balls is reduced when the particle size is too large, the green balls are easy to be broken when being distributed on a sintering machine, and the air permeability of a sintering material layer is reduced.
In the existing sintering process, the sintering mixture is usually sintered in a sintering machine after being subjected to secondary mixing pelletizing, the secondary mixing is a cylinder mixer, and the pelletizing and pelletizing effects are limited, so that the particle size distribution of green pellets of the sintering material after secondary mixing in the existing sintering process is generally 4-5 mm. In the invention, various dusts generated in the blast furnace and sintering process are subjected to special grinding, mixing and mixed grinding steps to improve the fineness and the specific surface area of each dust, so that the dusts are mutually permeated and fully mixed to improve the balling performance of the dusts, and finally, the green dust balls with the particle size distribution of 8-16mm (preferably 9-15mm, more preferably 10-14mm) are prepared in the balling step. Therefore, the green dust balls prepared in the invention are not required to participate in secondary mixing of the existing sintering process, but are directly arranged on a sintering machine trolley together with the uniformly mixed ore after secondary mixing for sintering, so that the green dust balls with larger particle sizes and the green sintering material balls with smaller particle sizes are distributed through segregation of a distributor of the sintering machine, and the green dust balls and the green sintering material balls are layered according to particle sizes, wherein the green dust balls with larger particle sizes are concentrated at the lower part of a sintering material layer to play a skeleton role, thereby effectively improving the air permeability of the sintering material layer.
In the dust granulation process, the corresponding weight of each dust and an alkalinity regulator (preferably quicklime) is weighed according to the proportion of the mixture to obtain a dust mixture; conveying the dust ingredient to a high-pressure roller mill by a apron conveyor for grinding to obtain the ground dust ingredient; conveying the ground dust ingredients to a powerful mixer by a apron conveyor for mixing, adding water while mixing, and fully and uniformly mixing the dust ingredients to obtain a dust mixture; conveying the dust mixture to a moistening and grinding machine by using a belt conveyor for moistening and grinding, adding a binder (preferably bentonite), and further uniformly mixing to obtain a moistened and ground dust mixture; and (3) conveying the wet and ground dust mixture to a pelletizer by a belt conveyor for pelletizing and pelletizing, and adding water while pelletizing to prepare the dust green pellets with larger particle size (8-16mm, preferably 9-15mm, and more preferably 10-14 mm). The dust green ball participates in the subsequent sintering process to form a new iron ore sintering process. In the iron ore sintering process, the prepared green dust balls and the mixed ore obtained by mixing the sintering mixture in the existing sintering process are arranged on a sintering machine trolley together for sintering, and the green dust balls and the sintered green material balls are layered according to the particle size through segregation distribution of a sintering machine distributor, so that the air permeability of a sintering material layer is effectively improved.
In the invention, the grinding adopts a high-pressure roller mill. The mixing adopts an intensive mixer. The mixing and grinding adopts a moistening and grinding machine. The pelletizing machine is used for one time, and a water supply device is arranged on a pelletizing disc of the pelletizing machine, wherein the water supply device is preferably an atomizing nozzle, so that the pulverized dust mixture is pelletized on the pelletizing machine under the condition of spraying water.
In the invention, the addition amount of quicklime in the step 1), the addition amount of water in the step 3) and the addition amount of bentonite in the step 4) are the weight ratios of the respective components to the total amount of the whole dust ingredient.
Compared with the prior art, the invention has the following beneficial effects:
1. various dusts generated in blast furnaces and sintering processes of steel plants usually contain high beneficial components such as Fe, CaO, MgO, fixed carbon and the like, and can be used as substitutes of sintering raw fuels; but the direct addition of the powder into the sintering raw materials can increase the dust pollution of the whole process of the original sintering process and greatly influence the air permeability, the production quality and the production organization of the sintering process; at present, the actual annual recovery utilization rate of the dust in the blast furnace and the sintering is kept about 80 percent of the annual generation amount, and 20 percent of waste (mainly secondary dust of the blast furnace) wastes limited resources and pollutes the environment; the dust granulation process and the subsequent sintering process effectively solve the problems of resource waste and environmental pollution;
2. according to the dust granulation process provided by the invention, each fine particle dust is prepared into the pellet with larger particle size and higher strength through the working procedures of material preparation, grinding, mixing, mixed grinding and pelletizing, the process is simple, the dust granulation effect is good, and the prepared green dust pellet has better components; the dust is treated in a closed and concentrated manner with high efficiency, so that the resource waste is avoided, and the environmental pollution and the comprehensive cost are reduced;
3. the iron ore sintering process provided by the invention based on dust granulation arranges the prepared dust green pellets and the uniformly mixed ore obtained by mixing the sintering mixture in the existing sintering process on a sintering machine trolley for sintering, effectively utilizes beneficial components such as Fe, CaO, MgO, fixed carbon and the like in dust, and simultaneously segregates cloth to ensure that the dust green pellets with larger grain diameter are mainly concentrated at the lower part of a sintering material layer, the sintering material green pellets with smaller grain diameter obtained after mixing are covered on the dust green pellets, the dust green pellets with larger grain diameter play a good role of a framework, the air permeability of the sintering material layer is effectively improved, and the quality of the product of the sintering ore is improved;
4. in the invention, after the prepared green dust balls are mixed and sintered, on one hand, the adverse effect caused by directly mixing and sintering the dust in the existing dust treatment mode can be improved, on the other hand, the usage amount of the coke powder can be reduced, the purposes of saving energy and reducing consumption are achieved, and simultaneously, after the air permeability of a sinter bed is improved, the thickness of the sinter bed can be increased, thereby reducing the burningThe solid fuel consumption is reduced, the resources are saved, and the SOx, NOx and CO in the sintering process are reduced from the source2And (4) generating.
Drawings
FIG. 1 is a flow chart of a dust pelletizing process and a subsequent sintering process of the present invention.
Detailed Description
According to a first embodiment of the invention, there is provided a dust granulation process:
a dust granulation process, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet and ground dust mixture to obtain the green dust balls.
In the present invention, the green dust balls obtained in step 5) have a particle size of 8 to 16mm, preferably 9 to 15mm, more preferably 10 to 14 mm.
Preferably, the moisture content of the dust green pellets obtained in step 5) is 9 to 13%, preferably 9.6 to 12.5%, more preferably 10 to 12%.
In the invention, various dusts generated in the blast furnace and/or sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash.
Preferably, in the step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail fly ash, sintering finished product fly ash, sintering ingredient fly ash, sintering main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; preferably 10 to 15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
In the present invention, the alkalinity regulator in step 1) is quicklime. Preferably, the amount of quicklime added is less than 2%, preferably less than 1%. Preferably, the quicklime has a particle size of 0 to 5mm, preferably 0.5 to 3 mm.
In the invention, the dust ingredient added with the alkalinity regulator is ground in the step 2), and the granularity of the dust is ground to-200 meshes which is more than 70 percent, preferably more than 75 percent, and more preferably more than 80 percent.
In the present invention, water is added to the dust blend after the grinding in step 3) when the dust blend is mixed. Preferably, the amount of water added is 5 to 8%, preferably 6 to 7%.
Preferably, the mixing time in step 3) is 30 to 60s, preferably 35 to 50 s.
In the invention, the binder in the step 4) is bentonite. Preferably, the bentonite is ground before being added to the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is more than 80%, preferably more than 90%. Preferably, the amount of bentonite added is 0.5 to 6%, preferably 1 to 4%.
Preferably, the time for the mixed grinding in the step 4) is 1-15min, preferably 2.5-10 min.
In the invention, water is added to the dust mixture after the wet grinding in the step 5) when the granulation is carried out on the dust mixture.
Preferably, the time for pelletizing in step 5) is 8-16min, preferably 10-15 min.
Preferably, the grinding in the step 2) adopts a high-pressure roller mill.
Preferably, an intensive mixer, preferably a vertical intensive mixer, is used for the mixing in step 3).
Preferably, the mixing and grinding in the step 4) adopts a wet grinding machine.
According to a second embodiment of the present invention, there is provided an iron ore sintering process:
a process for sintering iron ore, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
6) and (3) sintering: adding the dust green balls obtained in the step 5) into the uniformly mixed ore obtained after the sintering mixture is secondarily mixed, and sintering the uniformly mixed ore in a sintering machine.
In the present invention, the particle size distribution of the dust green pellets obtained in step 5) is 8 to 16mm, preferably 9 to 15mm, more preferably 10 to 14 mm.
Preferably, the moisture content of the dust green pellets obtained in step 5) is 9 to 13%, preferably 9.6 to 12.5%, more preferably 10 to 12%.
In the invention, various dusts generated in the blast furnace and/or sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash.
Preferably, in the step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sintering machine tail fly ash, sintering finished product fly ash, sintering ingredient fly ash, sintering main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; preferably 10 to 15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
In the present invention, the alkalinity regulator in step 1) is quicklime. Preferably, the amount of quicklime added is less than 2%, preferably less than 1%. Preferably, the quicklime has a particle size of 0 to 5mm, preferably 0.5 to 3 mm.
In the invention, the dust ingredient added with the alkalinity regulator is ground in the step 2), and the granularity of the dust is ground to-200 meshes which is more than 70 percent, preferably more than 75 percent, and more preferably more than 80 percent.
In the present invention, water is added to the dust blend after the grinding in step 3) when the dust blend is mixed. Preferably, the amount of water added is 5 to 8%, preferably 6 to 7%.
Preferably, the mixing time in step 3) is 30 to 60s, preferably 35 to 50 s.
In the invention, the binder in the step 4) is bentonite. Preferably, the bentonite is ground before being added to the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is more than 80%, preferably more than 90%. Preferably, the amount of bentonite added is 0.5 to 6%, preferably 1 to 4%.
Preferably, the time for the mixed grinding in the step 4) is 1-15min, preferably 2.5-10 min.
In the invention, water is added to the dust mixture after the wet grinding in the step 5) when the granulation is carried out on the dust mixture.
Preferably, the time for pelletizing in step 5) is 8-16min, preferably 10-15 min.
Preferably, the grinding in the step 2) adopts a high-pressure roller mill.
Preferably, an intensive mixer, preferably a vertical intensive mixer, is used for the mixing in step 3).
Preferably, the mixing and grinding in the step 4) adopts a wet grinding machine.
Example 1
A dust granulation process, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and the sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet and ground dust mixture to obtain the green dust balls.
The various dusts generated in the blast furnace and the sintering process in the step 1) comprise blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main power dedusting ash and steelmaking molten steel refining dedusting ash. Wherein, the weight ratio of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw materials ash, sintering machine tail fly ash, sintering finished product fly ash, sintering batching fly ash, main electric fly ash of sintering, the concise fly ash of steelmaking molten steel is 12: 8: 8: 36: 18: 17: 1: 1. the alkalinity regulator in the step 1) is quicklime. The amount of quicklime added was 0.8%. The particle size of the quicklime is 0.5-3 mm.
And 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is more than 70%.
Adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed. The water addition amount is 6%. The mixing time in step 3) was 40 s.
In the step 4), the binder is bentonite. The bentonite is ground before being added into the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is larger than 80%. The addition amount of bentonite is 1%. The time for mixing and grinding in the step 4) is 10 min.
Adding water into the dust mixture after the wet grinding in the step 5) when pelletizing. The pelletizing time in the step 5) is 10 min.
And 2) grinding by using a high-pressure roller mill. In the step 3), a vertical intensive mixer is adopted for mixing. And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
The particle size of the dust green ball obtained in the step 5) is 8.5 mm. The moisture content of the green dust balls obtained in the step 5) was 11.7%.
Example 2
Example 1 is repeated except that the dust ingredient added with the alkalinity regulator is ground in the step 2), and the granularity of the dust is ground to-200 meshes which is more than 80%. The water adding amount of the powder-ground dust ingredients in the step 3) is 7% during mixing. And 4) grinding the bentonite before adding the dust mixture in the step 4), wherein the granularity of the bentonite is ground to-325 meshes which is larger than 90%. The addition amount of bentonite is 4%. The pelletizing time in the step 5) is 15 min.
The particle size of the dust green ball obtained in the step 5) is 12 mm. The moisture content of the dust green ball obtained in the step 5) is 11.9%.
Example 3
A process for sintering iron ore, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and the sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
6) and (3) sintering: adding the dust green balls obtained in the step 5) into the uniformly mixed ore obtained after the sintering mixture is secondarily mixed, and sintering the uniformly mixed ore in a sintering machine.
The various dusts generated in the blast furnace and the sintering process in the step 1) comprise blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main power dedusting ash and steelmaking molten steel refining dedusting ash. Wherein, the weight ratio of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw materials ash, sintering machine tail fly ash, sintering finished product fly ash, sintering batching fly ash, main electric fly ash of sintering, the concise fly ash of steelmaking molten steel is 12: 8: 8: 36: 18: 17: 1: 1. the alkalinity regulator in the step 1) is quicklime. The amount of quicklime added was 0.8%. The particle size of the quicklime is 0.5-3 mm.
And 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is more than 70%.
Adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed. The water addition amount is 6%. The mixing time in step 3) was 40 s.
In the step 4), the binder is bentonite. The bentonite is ground before being added into the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is larger than 80%. The addition amount of bentonite is 1%. The time for mixing and grinding in the step 4) is 10 min.
Adding water into the dust mixture after the wet grinding in the step 5) when pelletizing. The pelletizing time in the step 5) is 10 min.
The moisture content of the green dust balls obtained in the step 5) was 11.7%.
And 2) grinding by using a high-pressure roller mill. In the step 3), a vertical intensive mixer is adopted for mixing. And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
Example 4
Example 3 was repeated except that the various dusts generated in the blast furnace and sintering process described in step 1) included blast furnace secondary ash, blast furnace cast house ash, blast furnace raw material ash, sinter tail fly ash, sinter end fly ash, sinter batch fly ash, sinter main electric fly ash, and steel-making molten steel refining fly ash. Wherein, the weight ratio of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw materials ash, sintering machine tail fly ash, sintering finished product fly ash, sintering batching fly ash, main electric fly ash of sintering, the concise fly ash of steelmaking molten steel is 12: 8: 8: 36: 18: 17: 1: 1. the alkalinity regulator in the step 1) is quicklime. The addition amount of quicklime is 0.5%. The particle size of the quicklime is 1-2 mm.
And 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is larger than 75%.
Adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed. The water addition amount is 5%. The mixing time in step 3) was 50 s.
In the step 4), the binder is bentonite. The bentonite is ground before being added into the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is larger than 90%. The addition amount of bentonite is 3%. The time for mixing and grinding in the step 4) is 6 min.
Adding water into the dust mixture after the wet grinding in the step 5) when pelletizing. The pelletizing time in the step 5) is 12 min.
The moisture content of the green dust balls obtained in the step 5) was 11.7%.
And 2) grinding by using a high-pressure roller mill. In the step 3), a vertical intensive mixer is adopted for mixing. And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
Comparative example 1
A process for sintering iron ore, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and the sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
6) and (3) sintering: adding the green dust balls obtained in the step 5) and the sintering mixture into a secondary mixing process for secondary mixing, and then putting the green dust balls and the sintering mixture into a sintering machine for sintering.
The various dusts generated in the blast furnace and the sintering process in the step 1) comprise blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main power dedusting ash and steelmaking molten steel refining dedusting ash. Wherein, the weight ratio of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw materials ash, sintering machine tail fly ash, sintering finished product fly ash, sintering batching fly ash, main electric fly ash of sintering, the concise fly ash of steelmaking molten steel is 15: 10: 10: 32: 15: 18: 2: 2. the alkalinity regulator in the step 1) is quicklime. The amount of quicklime added was 0.8%. The particle size of the quicklime is 0.5-3 mm.
And 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is more than 70%.
Adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed. The water addition amount is 6%. The mixing time in step 3) was 40 s.
In the step 4), the binder is bentonite. The bentonite is ground before being added into the dust mixture, and the particle size of the bentonite is ground to-325 meshes which is larger than 80%. The addition amount of bentonite is 1%. The time for mixing and grinding in the step 4) is 10 min.
Adding water into the dust mixture after the wet grinding in the step 5) when pelletizing. The pelletizing time in the step 5) is 10 min.
The moisture content of the green dust balls obtained in the step 5) was 11.7%.
And 2) grinding by using a high-pressure roller mill. In the step 3), a vertical intensive mixer is adopted for mixing. And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
Comparative example 2
Example 3 was repeated except that the quicklime in step 1) had a particle size of 6 mm.
And 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to 60 percent of minus 200 meshes.
In the step 4), the binder is bentonite. The bentonite is ground before being added into the dust mixture, and the particle size of the bentonite is ground to-325 meshes of 65 percent. The addition amount of bentonite is 3%. The time for mixing and grinding in the step 4) is 6 min.
The technical effects of the technical solutions of the respective examples are recorded as follows.
Table 1 test results data
As can be seen from the above table, in examples 3 and 4 of the present invention, the dust is separately granulated into green pellets with a large particle size, and the green pellets are distributed on a sintering machine together with other sintering materials to be sintered; compared with the comparative example 1, in the technical scheme of the invention, the dust green pellets play a skeleton role in the sintering material, so that the ventilation performance is improved, the material layer thickness on the sintering machine can be increased, the use of fuel is reduced, the energy consumption of a fan is saved, and the generation of nitrogen oxides is reduced.
In embodiments 3 and 4 of the invention, various raw materials granulated into the dust green ball are strictly ground to a specified particle size according to requirements, and the diameter of the prepared dust green ball is 8.5 mm; in comparative example 2, the diameter of each raw material was relatively large, and the diameter of the dust green pellets produced was 6.1 mm. The test results show that when the diameter of the dust green ball is smaller, the skeleton effect is not obvious, the diameter of the dust green ball prepared by the method is larger than 8mm, the ventilation performance improvement effect is better, the fuel use is reduced, the energy consumption of a fan is reduced, and the generation amount of nitrogen oxides is also reduced.

Claims (29)

1. A dust granulation process, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
the various dusts generated in the blast furnace and/or the sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash; step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sinter tail fly ash, sinter finished product fly ash, sinter burdening fly ash, sinter main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; the alkalinity regulator is quicklime; the addition amount of the quicklime is less than 2 percent; the particle size of the quicklime is 0-5 mm;
the binder in the step 4) is bentonite; grinding the bentonite before adding the dust mixture, and grinding the particle size of the bentonite to-325 meshes which is more than 80%; the addition amount of the bentonite is 0.5-6%; the mixing and grinding time in the step 4) is 1-15 min;
the moisture content of the dust green ball obtained in the step 5) is 9-13%; the particle size of the obtained dust green ball is 8-16 mm.
2. A process for sintering iron ore, the process comprising the steps of:
1) preparing materials: various dusts generated in the blast furnace and/or sintering process are proportioned, and an alkalinity regulator is added into the proportioned dusts to obtain dust proportioned materials;
2) grinding: grinding the dust ingredient added with the alkalinity regulator to obtain a ground dust ingredient;
3) mixing: mixing the ground dust ingredients to obtain a dust mixture;
4) mixing and grinding: adding a binder into the dust mixture, and carrying out damp grinding to obtain a damp-ground dust mixture;
5) pelletizing: pelletizing the wet-milled dust mixture to obtain green dust balls;
6) and (3) sintering: adding the dust green balls obtained in the step 5) into the uniformly mixed ore obtained after the sintering mixture is mixed twice, and sintering the uniformly mixed ore in a sintering machine;
the various dusts generated in the blast furnace and/or the sintering process in the step 1) are one or more of blast furnace secondary ash, blast furnace casting house ash, blast furnace raw material ash, sintering machine tail dedusting ash, sintering finished product dedusting ash, sintering ingredient dedusting ash, sintering main electric dedusting ash and steelmaking molten steel refining dedusting ash; step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sinter tail fly ash, sinter finished product fly ash, sinter burdening fly ash, sinter main electric fly ash and steelmaking molten steel refining fly ash is 8-20: 3-15: 3-15: 30-40: 10-25: 10-25: 0.1-3: 0.1 to 3; the alkalinity regulator is quicklime; the addition amount of the quicklime is less than 2 percent; the particle size of the quicklime is 0-5 mm;
the binder in the step 4) is bentonite; grinding the bentonite before adding the dust mixture, and grinding the particle size of the bentonite to-325 meshes which is more than 80%; the addition amount of the bentonite is 0.5-6%; the mixing and grinding time in the step 4) is 1-15 min;
the moisture content of the dust green ball obtained in the step 5) is 9-13%; the particle size of the obtained dust green ball is 8-16 mm.
3. The process according to claim 1 or 2, characterized in that: the particle size of the dust green ball obtained in the step 5) is 9-15 mm;
the moisture content of the dust green ball obtained in the step 5) is 9.6-12.5%.
4. The process according to claim 3, characterized in that: the particle size of the dust green ball obtained in the step 5) is 10-14 mm;
the moisture content of the dust green ball obtained in the step 5) is 10-12%.
5. The process according to any one of claims 1, 2, 4, wherein: step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sinter tail fly ash, sinter finished product fly ash, sinter burdening fly ash, sinter main electric fly ash and steelmaking molten steel refining fly ash is 10-15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
6. The process according to claim 3, characterized in that: step 1), the weight ratio of secondary blast furnace ash, blast furnace cast house ash, blast furnace raw material ash, sinter tail fly ash, sinter finished product fly ash, sinter burdening fly ash, sinter main electric fly ash and steelmaking molten steel refining fly ash is 10-15: 5-10: 5-10: 34-38: 15-20: 15-20: 0.5-2: 0.5-2.
7. The process of any one of claims 1-2, 4, 6, wherein: in the step 1), the addition amount of the quicklime is less than 1%; the particle size of the quicklime is 0.5-3 mm.
8. The process according to claim 3, characterized in that: in the step 1), the addition amount of the quicklime is less than 1%; the particle size of the quicklime is 0.5-3 mm.
9. The process of any one of claims 1-2, 4, 6, 8, wherein: and 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is more than 70%.
10. The process according to claim 3, characterized in that: and 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is more than 70%.
11. The process according to claim 9, characterized in that: and 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is larger than 75%.
12. The process according to claim 10, characterized in that: and 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is larger than 75%.
13. The process according to claim 11 or 12, characterized in that: and 2) grinding the dust ingredient added with the alkalinity regulator in the step 2), and grinding the granularity of the dust to-200 meshes which is larger than 80%.
14. The process of any one of claims 1-2, 4, 6, 8, 10-12, wherein: adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed; the water addition amount is 5-8%; and/or
The mixing time in the step 3) is 30-60 s.
15. The process according to claim 3, characterized in that: adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed; the water addition amount is 5-8%; and/or
The mixing time in the step 3) is 30-60 s.
16. The process according to claim 14, characterized in that: adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed; the water addition amount is 6-7%; and/or
The mixing time in the step 3) is 35-50 s.
17. The process of claim 15, wherein: adding water into the dust ingredients after grinding in the step 3) when the dust ingredients are mixed; the water addition amount is 6-7%; and/or
The mixing time in the step 3) is 35-50 s.
18. The process of any one of claims 1-2, 4, 6, 8, 10-12, 15-17, wherein: grinding the granularity of the bentonite in the step 4) to-325 meshes which is larger than 90 percent; the addition amount of bentonite is 1-4%.
19. The process according to claim 3, characterized in that: grinding the granularity of the bentonite in the step 4) to-325 meshes which is larger than 90 percent; the addition amount of bentonite is 1-4%.
20. The process of claim 18, wherein: the time for mixing and grinding in the step 4) is 2.5-10 min.
21. The process of claim 19, wherein: the time for mixing and grinding in the step 4) is 2.5-10 min.
22. The process of any one of claims 1-2, 4, 6, 8, 10-12, 15-17, 19-21, wherein: adding water into the dust mixture after the wet grinding in the step 5) when pelletizing; and/or
The pelletizing time in the step 5) is 8-16 min.
23. The process according to claim 3, characterized in that: adding water into the dust mixture after the wet grinding in the step 5) when pelletizing; and/or
The pelletizing time in the step 5) is 8-16 min.
24. The process of claim 22, wherein: the pelletizing time in the step 5) is 10-15 min.
25. The process of claim 23, wherein: the pelletizing time in the step 5) is 10-15 min.
26. The process of any one of claims 1-2, 4, 6, 8, 10-12, 15-17, 19-21, 23-25, wherein: the grinding in the step 2) adopts a high-pressure roller mill; and/or
An intensive mixer is adopted for mixing in the step 3); and/or
And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
27. The process according to claim 3, characterized in that: the grinding in the step 2) adopts a high-pressure roller mill; and/or
An intensive mixer is adopted for mixing in the step 3); and/or
And the mixing and grinding in the step 4) adopts a moistening and grinding machine.
28. The process of claim 26, wherein: in the step 3), a vertical intensive mixer is adopted for mixing.
29. The process of claim 27, wherein: in the step 3), a vertical intensive mixer is adopted for mixing.
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