CN101538633A - Method for improving quality of direct reduced iron by rotary hearth furnace - Google Patents
Method for improving quality of direct reduced iron by rotary hearth furnace Download PDFInfo
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- CN101538633A CN101538633A CN200910094380A CN200910094380A CN101538633A CN 101538633 A CN101538633 A CN 101538633A CN 200910094380 A CN200910094380 A CN 200910094380A CN 200910094380 A CN200910094380 A CN 200910094380A CN 101538633 A CN101538633 A CN 101538633A
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Abstract
The invention provides a method for improving quality of direct reduced iron by a rotary hearth furnace. The method breaks and fine grinds the iron which is directly reduced by the rotary hearth furnace to fine powder of 2mm, carries out the magnetic separation under the condition that the strength of a magnetic field is 110-160kA/m for selecting iron powder and gangue, compresses into the direct reduced iron product with the density of being greater than 4t/m<3> after filtration and drying and then directly pours into a furnace for steelmaking. The method can not only remove residual carbon and ash mixed in the direct reduced iron by the rotary hearth furnace, but also remove most of S brought by coal powder and the gangue in iron ores, thereby significantly improving the quality of the direct reduced iron, being directly used for steelmaking in an electric furnace and a rotary furnace and effectively reducing the production cost; tests prove that the direct reduced iron during the grinding and selection process can not generate the secondary oxidation basically, the recovery rate of the metal iron is generally higher than 95 percent, the highest can achieve 99 percent, and the metal loss is less.
Description
Technical field
The present invention relates to a kind of method that improves quality of direct reduced iron by rotary hearth furnace, belong to the smelting iron and steel technical field.
Technical background
The direct reduction iron making technology is meant that iron ore is being lower than under the temperature of fusion, is reduced into the production process of sponge iron, and it is the developing direction of following ironmaking technology, also is one of significant technology innovation project that national industrial policies are encouraged and emphasis is supported.According to employed reductive agent classification, the direct reduction iron making technology can be divided into the gas base method of gas as reductive agent, and with the coal-based method two big classes of coal as reductive agent.Surpassing 80% direct-reduced iron at present in the world, all is to be produced by gas base directly reducing technology, and the output of coal base reduction iron is less than 20%.The gas base directly reducing technology comparative maturity, use the countries and regions that are adapted at rich producing natural gas, and the coal-based direct reduction technological development relatively lags behind, and is adapted at lacking Sweet natural gas, and use the abundant countries and regions of coal reserves.China's natural gas source is relatively deficienter, therefore is not suitable for promoting the use of in China with the gas base directly reducing technology of Sweet natural gas as reductive agent, and should be in conjunction with the resources characteristic of China, development and use have the coal-based direct reduction iron technology of self-character.
The rotary hearth furnace technology originates from the Canada and the U.S. the earliest, has had nearly 30 years steady running experience.Its technological process is the mixture of iron ore or other iron-bearing materials, solid state reduction agent, binding agent and water to be made the carbonaceous pelletizing of 9～15mm in balling equipment or pressure ball equipment, send into rotary hearth furnace then, under 1350～1400 ℃ reducing atmosphere, roasting 15～30min produces the direct-reduced iron of degree of metalization 〉=85%.In the middle of numerous coal-based direct reduction iron-smelting process, the rotary hearth furnace technology is with its less investment, and cost is low, and wide characteristics of adaptability to raw material and receiving much attention.Compare with other direct reducing process, the advantage of the direct reducing process of rotary hearth furnace is that reduction temperature is high 200～300 ℃, and the recovery time is short more than 80%, investment and production cost low 20～40%; Shortcoming is: owing to need to add partly binding agent, and the coal dust of joining 20～30% in needing, the TFe of rotary hearth furnace process direct-reduced iron product is generally than low 10～15 percentage points of other technology, SiO
2Want high 2～3 percentage points, it is high 0.08～0.12 percentage point that S content is wanted, and density is light by 20～30%.So just cause direct reduced iron by rotary hearth furnace because low, gangue of grade and sulphur content height, and density is lower, and is difficult to be directly used in the converter and the Electric furnace steel making of postorder, this has also influenced the research and development of the direct reducing process of rotary hearth furnace to a great extent and has applied.
Summary of the invention
Low for overcoming direct reduced iron by rotary hearth furnace because of its TFe, SiO
2Height, problems such as S content height, thus be difficult to directly carry out deficiency such as STEELMAKING PRODUCTION, the invention provides a kind of method that improves quality of direct reduced iron by rotary hearth furnace, to improve its TFe content, reduce SiO
2Content and S content satisfy the STEELMAKING PRODUCTION requirement.
At rotary hearth furnace reduction temperature height, the grain size number of direct-reduced iron is big, be easy to sort and the direct-reduced iron carburizing more abundant, characteristics such as oxidation-resistance is better, the present invention realizes by following technical proposal: a kind of method that improves quality of direct reduced iron by rotary hearth furnace is characterized in that through following process steps:
A, with the fragmentation of the direct reductive iron of rotary hearth furnace, be finely ground to the fine powder below the 2mm, wherein-200 the purpose ratio reaches 20.00～35.00%;
B, be under the condition of 110～160kA/m in magneticstrength, the reduced iron of the fragmentation of A step, fine grinding is carried out magnetic separation, select iron powder and gangue, the gangue that dissociates is abandoned, and obtains high-quality iron powder;
C, after filtration, after the drying, be pressed into density greater than 4t/m with the iron powder that magneticly elects
3The direct-reduced iron product, can make steel directly into stove.
The fragmentation of described A step, fine grinding all adopt the conventional disintegrating apparatus of prior art to finish.
The magnetic separation of described B step adopts conventional XCT Φ 1000 * 2400 magnetic separators of prior art to carry out magnetic separation.
The filtration of described C step adopts the conventional ZPG-100 disk vacuum filter of prior art to dewater.
The drying of described C step is finished on Φ 2000m cylindrical drier, and drying temperature is 205～305 ℃, and the moisture content of dry back direct-reduced iron powder is 0～0.1%.
The conventional Y83-315SY briquetting press that prior art is adopted in the compacting of described C step is with the iron powder briquetting.
The present invention has following advantage and effect: adopt such scheme, not only can remove the carbon residue and the ash content that are mingled with in the direct reduced iron by rotary hearth furnace, can also remove S that most of coal dust brings into and the gangue in the iron ore, therefore can significantly improve the quality of direct-reduced iron, in addition, also have following advantage:
1, in the area that lacks fine quality iron concentrate and super sea coal, can suitably relax harsh requirement, produce the direct-reduced iron product that directly in electric furnace and converter, to make steel, for applying of the direct reducing process of rotary hearth furnace creates conditions to raw materials quality;
2, the direct reducing process of sophisticated rotary hearth furnace combines with widely used mill ore magnetic selection, direct-reduced iron powder compression moulding technology, both can bring into play the technical superiority of the direct reducing process of rotary hearth furnace to greatest extent, can effectively overcome the direct reduced iron by rotary hearth furnace product again is difficult to by the direct deficiency of using of steel making working procedure, the cost of direct reduced iron by rotary hearth furnace, except can remedying the expense that ore grinding is selected and the compression moulding operation is increased, compare with other direct-reduced iron technology and still can save 100～300 yuan/ton cost, its advantage is conspicuous;
3, through experimental verification, secondary oxidation can not take place in direct-reduced iron substantially in the ore grinding refining process, and the rate of recovery of metallic iron generally is higher than 95%, reaches as high as 99%, and metal loss is less.
Description of drawings
Fig. 1 is the present invention's process flow sheet.
Embodiment
Below by example the present invention is described further.
Embodiment 1
A, direct reduced iron by rotary hearth furnace: with TFe content be 62.41%, SiO
2Content is that 7.31% iron ore concentrate is a raw material, with addition of mass ratio is 24% coal dust and 3% wilkinite, RZD-105-14/16 type rotary hearth furnace experimental installation with prior art, under technology and technical qualification that the rotary hearth furnace of prior art is produced, roasting 30min, produce direct-reduced iron, wherein the composition of direct-reduced iron is: TFe:80.06%, SiO
2: 9.08%, S:0.18%, degree of metalization are 92.77%, the Chinese SiO in this and the table 1
2Metallkunde can be recommended the apart from each other that requires of " steel-making direct-reduced iron technical qualification ", sees Table 1;
B, A step gained direct-reduced iron is carried out following processing:
1), with after the conventional crusher in crushing of prior art, levigate to 2mm through ore mill again, wherein-200 the purpose ratio accounts for 20.00%;
2), be under the condition of 110kA/m in magneticstrength, with conventional XCT Φ 1000 * 2400 magnetic separators of prior art, to 1) reduced iron of step fragmentation, fine grinding carries out magnetic separation, selects iron powder and gangue, the gangue that dissociates is abandoned, and obtains high-quality iron powder;
3), the iron powder that magneticly elects filtered, dewaters with the ZPG-100 disk vacuum filter of prior art after, with moisture 7% the iron powder that filters out, with Φ 2000 cylindrical driers of prior art, under 205 ℃ of temperature, being dried to moisture content is 0.1%; With the conventional Y83-315SY chilling press of prior art, being pressed into granularity is that 20～100mm, density are greater than 4t/m
3The direct-reduced iron product, the chemical ingredients of this product is: TFe:91.99%, SiO
2: 3.44%, S:0.088%, degree of metalization are 93.67%.Wherein improve 14.90% before the more selected processing of TFe, SiO
2Reduce by 52.94%, S content reduces by 51.11%, and except that S content exceeded standard slightly, other composition all reached the specification of quality of " steel-making direct-reduced iron technical qualification " middle seconds of The Chinese Society for Metals's recommendation, as table 1, this product can directly supply with converter and Electric furnace steel making uses.
Embodiment 2
Equipment used is with embodiment 1;
A, direct reduced iron by rotary hearth furnace are with the A step of embodiment 1;
B, A step gained direct-reduced iron is carried out following processing:
1), with after the crusher in crushing of prior art, levigate to 2mm through ore mill again, wherein-200 the purpose ratio accounts for 35.00%;
2), be under the condition of 160kA/m in magneticstrength, with the conventional magnetic separator of prior art the reduced iron of the fragmentation of A step, fine grinding is carried out magnetic separation, select iron powder and gangue, the gangue that dissociates is abandoned, and obtains TFe:92.10%, SiO
2: 3.10%, S:0.085%, degree of metalization are 94.84% high quality iron powder;
3), the iron powder that magneticly elects filtered, dewaters with the ZPG-100 disk vacuum filter of prior art after, with moisture 9% the iron powder that filters out, with Φ 2000 cylindrical driers of prior art, under 205 ℃ of temperature, being dried to moisture content is 0.1%; Conventional Y83-315SY chilling press with prior art is pressed into density greater than 4t/m
3The direct-reduced iron product, can make steel directly into stove.
The steel-making direct-reduced iron technical qualification that table 1 The Chinese Society for Metals is recommended
| Grade | TFe ％ | M ％ | S ％ | P ％ | Acid gangue % | Chip index % | Volume density t/m 3 |
| One-level | ≥92 | ≥92 | ≤ 0.010 | ≤ 0.015 | ≤4.5 | ≤3.0 | ≥1.90 |
| Secondary | ≥90 | ≥92 | ≤ 0.020 | ≤ 0.030 | ≤5.5 | ≤5.0 | ≥1.80 |
| Three grades | ≥90 | ≥90 | ≤ 0.020 | ≤ 0.040 | ≤6.5 | ≤5.0 | ≥1.75 |
| Level Four | ≥88 | ≥90 | ≤ 0.030 | ≤ 0.050 | ≤7.5 | ≤5.0 | ≥1.75 |
Claims (3)
1, a kind of method that improves quality of direct reduced iron by rotary hearth furnace is characterized in that through following process steps:
A, with the fragmentation of the direct reductive iron of rotary hearth furnace, be finely ground to the fine powder below the 2mm, wherein-200 the purpose ratio reaches 20.00～35.00%;
B, be under the condition of 110～160kA/m, the reduced iron of the fragmentation of A step, fine grinding is carried out magnetic separation, select iron powder and gangue in magneticstrength;
C, after filtration, after the drying, be pressed into density greater than 4t/m with the iron powder that magneticly elects
3The direct-reduced iron product, can make steel directly into stove.
2, the method for raising quality of direct reduced iron by rotary hearth furnace as claimed in claim 1 is characterized in that the fragmentation of described A step, the conventional disintegrating apparatus that prior art is all adopted in fine grinding finish; The magnetic separation of described B step adopts the conventional magnetic separator of prior art to carry out magnetic separation; The filtration of described C step adopts the conventional disk vacuum filter of prior art to dewater; The compacting of described C step adopts the conventional briquetting press of prior art with the iron powder briquetting.
3, the method for raising quality of direct reduced iron by rotary hearth furnace as claimed in claim 1, the drying that it is characterized in that described C step is to finish in the prior art the conventional cylindrical drier, drying temperature is 205～305 ℃, and the moisture content of dry back direct-reduced iron powder is 0～0.1%.
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| CN2009100943809A CN101538633B (en) | 2009-04-21 | 2009-04-21 | Method for improving quality of direct reduced iron by rotary hearth furnace |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102162017A (en) * | 2011-03-18 | 2011-08-24 | 北京科技大学 | Method for comprehensively utilizing paigeite by rotary hearth furnace iron bead process |
| CN102424874A (en) * | 2011-12-05 | 2012-04-25 | 武汉科技大学 | Oolitic hematite aluminum and iron separation method |
| CN103042223A (en) * | 2012-12-21 | 2013-04-17 | 宁夏众磊鑫科技实业有限公司 | Reduced iron powder production process |
| CN104190950A (en) * | 2014-07-25 | 2014-12-10 | 玉溪大红山矿业有限公司 | Iron powder production process |
| CN107214342A (en) * | 2017-05-31 | 2017-09-29 | 武钢集团昆明钢铁股份有限公司 | A kind of reduced iron powder and preparation method thereof |
-
2009
- 2009-04-21 CN CN2009100943809A patent/CN101538633B/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102162017A (en) * | 2011-03-18 | 2011-08-24 | 北京科技大学 | Method for comprehensively utilizing paigeite by rotary hearth furnace iron bead process |
| CN102162017B (en) * | 2011-03-18 | 2012-10-10 | 北京科技大学 | Method for comprehensively utilizing paigeite by rotary hearth furnace iron bead process |
| CN102424874A (en) * | 2011-12-05 | 2012-04-25 | 武汉科技大学 | Oolitic hematite aluminum and iron separation method |
| CN103042223A (en) * | 2012-12-21 | 2013-04-17 | 宁夏众磊鑫科技实业有限公司 | Reduced iron powder production process |
| CN103042223B (en) * | 2012-12-21 | 2015-09-09 | 宁夏众磊鑫科技实业有限公司 | A kind of production technology of reduced iron powder |
| CN104190950A (en) * | 2014-07-25 | 2014-12-10 | 玉溪大红山矿业有限公司 | Iron powder production process |
| CN104190950B (en) * | 2014-07-25 | 2016-08-24 | 玉溪大红山矿业有限公司 | A kind of PRODUCTION OF IRON POWDER technique |
| CN107214342A (en) * | 2017-05-31 | 2017-09-29 | 武钢集团昆明钢铁股份有限公司 | A kind of reduced iron powder and preparation method thereof |
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