阅读说明：本技术 一种高炉炼铁用自熔性冷压复合炉料及其制备方法 (Self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking and preparation method thereof ) 是由 韩宏松 韩凤光 于 2020-05-27 设计创作，主要内容包括：本发明公开了一种高炉炼铁用自熔性冷压复合炉料及其制备方法,主要解决现有铁屑等细粉状含铁废弃物不能直接作为高炉炼铁炉料使用的技术问题。本发明提供的一种高炉炼铁用自熔性冷压复合炉料,其特征是,其化学成分的重量百分比为：Fe≥85％,SiO-(2)1.5～3.0％,CaO 1.0～3.0％,HO-(2)2～5％,其余不可避免的杂质,各组成组分的重量百分比之和为100％。冷压复合炉料常温落下强度≥6次/3m·个。本发明冷压复合炉料既可以作为一种高炉增产节能的炉料使用,又可以作为调剂高炉炉况炉料使用。(The invention discloses a self-fluxing cold-pressing composite furnace burden for blast furnace ironmaking and a preparation method thereof, and mainly solves the technical problem that the existing iron-containing fine powder wastes such as scrap iron and the like cannot be directly used as the blast furnace ironmaking furnace burden. The invention provides a self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking, which is characterized by comprising the following chemical components in percentage by weight: fe is more than or equal to 85 percent and SiO 2 1.5～3.0％，CaO 1.0～3.0％，HO 2 2-5 percent of the total weight of the components, and the balance of inevitable impurities, wherein the sum of the weight percentages of the components is 100 percent. The normal temperature falling strength of the cold-pressed composite furnace charge is more than or equal to 6 times per 3 m. The cold-pressed composite furnace burden can be used as a furnace burden for increasing the yield and saving energy of a blast furnace and can also be used as a furnace burden for regulating the condition of the blast furnace.)

1. A self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking is characterized by comprising the following chemical components in percentage by weight: fe is more than or equal to 85 percent and SiO₂ 1.5～3.0％，CaO 1.0～3.0％,HO₂2-5 percent of the total weight of the components, and the balance of inevitable impurities, wherein the sum of the weight percentages of the components is 100 percent.

2. The self-fluxing cold-pressing composite charge for blast furnace ironmaking according to claim 1, wherein the self-fluxing cold-pressing composite charge is prepared from iron filings, limestone and silica sol according to the composition of claim 1.

3. The self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking according to claim 2, which comprises 90-93% of scrap iron, 3-5% of limestone and 4-6% of silica sol by weight, wherein the sum of the weight percentages of the raw material components is 100%.

4. The self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking according to claim 2 or 3, characterized in that the raw materials comprise, by weight: fe is more than or equal to 95 percent, and Zn is less than or equal to 0.01 percent; limestone: 48-55% of CaO; silica sol: SiO 2₂ 40～50％。

5. The self-fluxing cold-pressing composite charge for blast furnace ironmaking according to claim 2, wherein the particle size of the scrap iron is less than or equal to 5mm, and the particle size of the limestone is less than or equal to 2 mm.

6. The self-fluxing cold-pressed composite charge for blast furnace ironmaking according to claim 1, wherein the self-fluxing cold-pressed composite charge has the shape and size: phi is 20-30 mm.

7. The self-fluxing cold-pressing composite charging material for blast furnace ironmaking according to claim 1, wherein the cold-pressing composite charging material has a normal temperature dropping strength of not less than 6 times/3 m-pieces; the cold-pressed composite furnace burden is kept at the temperature below 900 ℃ and at the temperature of 900 ℃ for 30 minutes, the cold-pressed composite furnace burden is not pulverized, has no obvious soft melting region, and can fully drop below 1400 ℃ in a blast furnace environment.

8. A method of preparing the self-fluxing cold-pressed composite charge of claim 1 for blast furnace ironmaking, comprising the steps of:

1) proportioning, namely weighing iron chips, limestone and silica sol according to the proportion;

2) mixing materials, namely uniformly mixing iron chips, limestone and silica sol materials by using a stirrer, wherein the uniformly mixed materials comprise the following components in percentage by weight: 90-93% of scrap iron, 3-5% of limestone and 4-6% of silica sol, wherein the sum of the weight percentages of the raw material components is 100%;

3) and (5) cold-pressing the mixture into spheres, and performing cold-pressing on the uniformly mixed material into spheres by using a double-roll press.

9. The method for preparing the self-fluxing cold-pressing composite charging material for blast furnace ironmaking according to claim 8, wherein in the step 3), the working pressure of the double-roll press is controlled to be 300-500 MPa; the shape and the size of the cold-pressing composite furnace charge are controlled to be phi 20-30 mm.

10. A blast furnace iron-making method by adopting self-fluxing cold-pressing composite furnace charge comprises the following steps:

1) preparing iron ore raw materials, and preparing the iron ore raw materials according to the control requirement that the slag-iron ratio is less than or equal to 300kg/t, wherein the iron ore raw materials comprise the following components in percentage by mass: 70-85% of sintered ore, 15-20% of lump ore, less than or equal to 12% of cold-pressing composite furnace burden, the sum of the weight percentages of the components in the iron ore raw material is 100%, and the binary alkalinity R of the iron ore raw material is controlled₂1.60 to 1.70;

2) distributing, namely alternately distributing coke and iron ore raw materials into a blast furnace to form an alternate layered structure of an ore layer and a coke layer, wherein various materials in the iron ore layer exist in the material layer in a mixed state;

3) blast furnace smelting, controlling molten iron temperature T in the smelting process_pThe temperature of the furnace slag is more than or equal to 1480 ℃, and the temperature of the furnace slag is more than or equal to 1500 ℃;

4) and (4) normally tapping.

Technical Field

The invention relates to furnace burden for blast furnace ironmaking, in particular to self-fluxing cold-pressing composite furnace burden for blast furnace ironmaking and a preparation method thereof, and belongs to the technical field of blast furnace ironmaking.

Background

At present, the total amount of scrap steel generated in China every year is about 2 hundred million tons, more than 80% of the scrap steel can be recycled for converter steelmaking, however, one part of the scrap steel is scrap steel such as iron shavings and processing scrap iron, and is limited by technological economic conditions, the part of scrap steel is difficult to be directly used for steelmaking procedures, a blast furnace has remarkable advantages in the yield of iron elements and smelting efficiency, and if the iron-containing wastes can be used for blast furnace ironmaking, the economic and technical level of the application can be remarkably improved.

Because the blast furnace smelting process has higher requirements on the granularity, the strength, the relevant metallurgical performance and the like of the raw materials entering the furnace, the raw materials must be processed firstly.

The traditional sintering and pelletizing process is not suitable for the treatment method of the waste iron filings generated by processing, because the sintering and pelletizing process utilizes the low-melting-point characteristic of minerals such as silicate, ferrite and the like formed by ores and added fluxing agents in the high-temperature process to form a binding phase, the sintered pellets obtain good strength and other metallurgical properties, the main component of the iron-containing waste is metallic iron, the mass percentage content of iron in the iron-containing waste is not less than 95 percent, the difference of the iron-containing waste and the phase composition of iron ore is huge, and the process condition of the sintered pellets is not suitable.

Other iron ore powder agglomeration methods also include a manufacturing method of iron coke, in the method, iron ore, coke powder and coal powder are added into a binder to be mixed, then the mixture is subjected to cold press molding, and then the mixture is dried at high temperature or is subjected to dry distillation at the temperature of more than 800 ℃, so that the finished iron coke has the comprehensive performance of coke and sintered pellets, the treatment process is complex, heat consumption is required, and the economical efficiency and the environmental protection are poor.

Chinese patent application publication No. CN101619386A discloses a blast furnace iron coke and its preparation and application, wherein the iron coke comprises, by mass, 10-70 wt% of coke powder, 20-82 wt% of an iron-containing raw material, and 8-10 wt% of a binder, and is prepared by cold press molding and then drying at 300-600 ℃ to obtain iron coke, and according to different requirements of a blast furnace, the iron coke with different performances is prepared by adjusting the proportion of related materials within the above proportion range.

In summary, most of the iron-containing materials in the conventional sintering and pelletizing process and the ferro coke production process are iron oxides, and high-temperature treatment is required to consume energy, and the iron element in the iron-containing waste exists basically in the form of metallic iron, so the treatment process is not suitable for processing the iron-containing waste in terms of economy, technology and environmental protection.

Disclosure of Invention

The invention aims to provide a self-fluxing cold-pressing composite furnace burden for blast furnace ironmaking and a preparation method thereof, and mainly solves the technical problem that the existing iron-containing fine powder waste such as scrap iron and the like cannot be directly used as the blast furnace ironmaking furnace burden.

The scrap iron is iron-containing waste formed in the process of machining steel parts.

The technical idea of the invention is that the iron filings are mixed with a certain proportion of silica gel binder and limestone, and then the mixture is cold-pressed into spherical furnace charge with proper grain size by a forming machine for blast furnace smelting.

The invention adopts the technical scheme that the self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking comprises the following chemical components in percentage by weight: fe is more than or equal to 85 percent and SiO₂1.5～3.0％，CaO1.0～3.0％,HO₂2-5 percent of the total weight of the components, and the balance of inevitable impurities, wherein the sum of the weight percentages of the components is 100 percent.

The self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking comprises, by weight, 90-93% of scrap iron, 3-5% of limestone and 4-6% of silica sol, wherein the sum of the weight percentages of the raw material components is 100%.

The cold-pressed composite furnace burden is spherical, and the shape and the size of the cold-pressed composite furnace burden are as follows: phi is 20-30 mm.

The reason why the chemical composition of the self-fluxing cold-pressing composite charging material for blast furnace ironmaking is limited in the range is as follows:

fe: the iron content of the cold-pressed composite furnace charge is more than 85 percent and is metallic iron, the iron content is more than 87 percent when the calculation is carried out after the moisture is deducted, the temperature is kept for 30 minutes at the low temperature zone of the blast furnace, specifically below 900 ℃ and at 900 ℃, the pulverization phenomenon can not occur, no obvious reflow zone exists, and the cold-pressed composite furnace charge can fully drop below 1400 ℃ in the blast furnace environment.

SiO₂: to SiO₂The limit of the content range is due to the addition ratio of the silica sol and the SiO thereof₂The content and the addition amount of the components are required to meet the molding requirement and the strength index after molding required by the cold-pressing composite furnace burden.

CaO: limitation of CaO content according to SiO in cold-pressed composite charge₂Content, finally the binary alkalinity CaO/SiO₂And the alkalinity is controlled to be 0.5-1.2, so that the slag alkalinity requirement of blast furnace smelting under the condition that different raw fuels are produced by the blast furnace is met.

The cold-pressed composite furnace burden can be used as a furnace burden for increasing the yield and saving energy of a blast furnace and can also be used as a furnace burden for regulating the condition of the blast furnace, the cold-pressed composite furnace burden is generally used in combination with conventional sintered ore and lump ore of the blast furnace, the using amount of the cold-pressed composite furnace burden is not more than 200 kg/ton/pig iron, and the specific selection is determined according to the specific conditions of the blast furnace. Because of its ultra-high iron content and traditional furnace charge have no comparable metallurgical energy, it can obviously raise blast furnace output and reduce fuel ratio.

The preparation method of the self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking comprises the following steps:

1) proportioning, namely weighing iron chips, limestone and silica sol according to the proportion;

2) mixing materials, namely uniformly mixing iron chips, limestone and silica sol materials by using a stirrer, wherein the uniformly mixed materials comprise the following components in percentage by weight: 90-93% of scrap iron, 3-5% of limestone and 4-6% of silica sol, wherein the sum of the weight percentages of the raw material components is 100%;

3) and (5) cold-pressing the mixture into spheres, and performing cold-pressing on the uniformly mixed material into spheres by using a double-roll press.

Further, in the step 3), the working pressure of the double-roll press is controlled to be 300-500 MPa; the shape and the size of the cold-pressing composite furnace charge are controlled to be phi 20-30 mm.

In the cold-pressing balling process of the cold-pressing composite furnace burden, the scrap iron can play a good role of a framework and is mutually occluded and linked, the silica sol plays a role of a binder, the formed cold-pressing composite furnace burden has good cold strength and hot strength, the falling strength at normal temperature is more than or equal to 6 times/3 m, and the furnace burden can not be scattered below 900 ℃.

The normal-temperature falling strength of the cold-pressed composite furnace burden is characterized in that the cold-pressed composite furnace burden vertically falls from a height of 3m and impacts on a Q195P steel floor, and the experiment is repeated, wherein the free falling times when the cold-pressed composite furnace burden is broken are the normal-temperature falling strength of the cold-pressed composite furnace burden.

The heat intensity of the cold-pressed composite furnace charge is that the cold-pressed composite furnace charge is kept at the temperature of below 900 ℃ and at the temperature of 900 ℃ for 30 minutes, and the cold-pressed composite furnace charge is not pulverized.

The raw materials of the invention comprise scrap iron, limestone and silica sol, and the raw materials comprise the following components in percentage by weight: scrap iron: fe is more than or equal to 95 percent, and Zn is less than or equal to 0.01 percent; limestone: 48-55% of CaO; silica sol: SiO 2₂40～50％。

The particle size of the scrap iron is less than or equal to 5 mm; the particle size of the limestone is less than or equal to 2 mm.

The blast furnace iron making method by adopting the cold-pressed composite furnace charge comprises the following steps:

1) preparing iron ore raw materials, and preparing the iron ore raw materials according to the control requirement that the slag-iron ratio is less than or equal to 300kg/t, wherein the iron ore raw materials comprise the following components in percentage by mass: 70-85% of sintered ore, 15-20% of lump ore, less than or equal to 12% of cold-pressing composite furnace burden, the sum of the weight percentages of the components in the iron ore raw material is 100%, and the binary alkalinity R of the iron ore raw material is controlled₂1.60 to 1.70;

2) distributing, namely alternately distributing coke and iron ore raw materials into a blast furnace to form an alternate layered structure of an ore layer and a coke layer, wherein various materials in the iron ore layer exist in the material layer in a mixed state;

3) blast furnace smelting, controlling molten iron temperature T in the smelting process_pThe temperature of the furnace slag is more than or equal to 1480 ℃, and the temperature of the furnace slag is more than or equal to 1500 ℃;

4) and (4) normally tapping.

After the cold-pressed composite furnace burden is added into a blast furnace, the iron content of the cold-pressed composite furnace burden is far higher than that of conventional iron ore, so that the slag ratio can be obviously reduced, the yield of the blast furnace is improved, and the fuel consumption is reduced; as the main component in the furnace burden is metallic iron, no pulverization occurs in the medium and low temperature zone.

The limestone is selected as the CaO adding flux, and besides the requirement of the components of the binary alkalinity of the limestone is met, the limestone is considered to generate decomposition reaction at 900 ℃: CaCO₃＝CaO+CO₂×) CO generation₂After escaping, small air holes are generated, which is beneficial to the carburization reaction: 3Fe (L) + C → Fe₃C, the furnace burden of the invention can be promoted to be carburized efficiently at the temperature of more than 900 ℃ and drop below 1400 ℃, the dropping temperature can be lower than that of main stream iron ore used by the blast furnace, so that the reflow interval of the mixed furnace burden can not be increased, and the permeability of the reflow zone of the blast furnace can be improved to a certain extent due to the absence of an obvious reflow interval, and the improvement of the technical and economic indexes of the blast furnace is promoted.

Compared with the prior art, the invention has the following positive effects: 1. the self-fluxing cold-pressing composite furnace charge has ultrahigh grade due to the use of a large amount of iron-containing waste, can obviously reduce the slag ratio of the blast furnace, improves the yield of the blast furnace and reduces the fuel consumption. 2. The self-fluxing cold-pressing composite furnace charge has no obvious reflow dripping performance in a high-temperature area of a blast furnace, can play a role of a skeleton of coke to a certain extent in the region of a reflow zone in the mixed use process of the self-fluxing cold-pressing composite furnace charge and conventional iron ore, can improve the air permeability of the reflow zone of the blast furnace, and promotes the improvement of the technical and economic indexes of the blast furnace. 3. The self-fluxing cold-pressing composite furnace charge does not generate pulverization in a blocky belt in the blast furnace, keeps a good original furnace entering granularity state, is beneficial to improving the air permeability of the blocky belt of the blast furnace, and promotes the improvement of the technical and economic indexes of the blast furnace. 4. The self-fluxing cold-pressing composite furnace charge adopts a cold-pressing molding process, has self-fluxing property, can select a proper range of binary alkalinity according to the actual condition of the blast furnace, reduces the use of blast furnace flux (mainly aiming at acid flux), can reduce the slag ratio, and promotes the realization of cost reduction and efficiency improvement of the blast furnace.

Detailed Description

The invention is further described below with reference to specific examples.

Embodiment 1, a self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking, which comprises the following chemical components in percentage by weight: fe 87%, SiO₂2.0％,CaO2.0％,HO₂2-5 percent of the total weight of the components, and the balance of inevitable impurities, wherein the sum of the weight percentages of the components is 100 percent.

The preparation method of the self-fluxing cold-pressing composite furnace charge for blast furnace ironmaking comprises the following steps:

1) proportioning, namely weighing scrap iron, silica sol and limestone according to a ratio;

2) mixing materials, namely uniformly mixing iron chips, limestone and silica sol materials by using a stirrer, wherein the uniformly mixed materials comprise the following components in percentage by weight: 93% of scrap iron and 3% of limestone; 4% of silica sol;

3) and (3) cold-pressing the mixture into spheres by using a double-roll press, wherein the shape and the size of the cold-pressed composite furnace charge are controlled to be phi 25mm, and the working pressure of the double-roll press is controlled to be 400 MPa.

In the cold-press molding process of the cold-press composite furnace burden, the existence of the binder ensures that the molded block furnace burden has good cold strength and the falling strength is 7 times/3 m.

1280m at a company³The blast furnace is used, the adding amount is 80 kg/ton pig iron, the adding mode is that the pig iron is mixed with the conventional iron ore sinter and lump ore of the blast furnace and then is distributed into the blast furnace, the iron is normally smelted, after the composite furnace burden is used, the furnace condition is maintained to be stable and smooth, the output of the blast furnace is improved by more than 10 percent, and the fuel ratio is reduced by 25 kg/t.

In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.