CN101691622B - Converter dephosphorization pretreatment and slagless decarburization method - Google Patents
Converter dephosphorization pretreatment and slagless decarburization method Download PDFInfo
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- CN101691622B CN101691622B CN2009100936595A CN200910093659A CN101691622B CN 101691622 B CN101691622 B CN 101691622B CN 2009100936595 A CN2009100936595 A CN 2009100936595A CN 200910093659 A CN200910093659 A CN 200910093659A CN 101691622 B CN101691622 B CN 101691622B
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Abstract
The invention relates to a converter dephosphorization pretreatment and slagless decarburization method, belonging to the field of converter steelmaking; the method is mainly used for dephosphorization pretreatment and slagless decarburization in the same converter or different converters, and the processes of top blowing oxygen and bottom blowing nitrogen and argon are adopted; in a decarburization period, dephosphorization agents with low melting point are used and low flow rate control is adopted, the scrap steel intake quantity is reduced by increasing ore adding quantity, the finish temperature is controlled to 1350-1400 DEG C, the carbon content is controlled to be 2.8-3.2 percent in a short time, in a decarbonization period, normal top blowing is adopted to supply air flow rate to meet period requirements, the decarburization finish temperature is controlled to be 1650-1720 DEG C, and the dephosphorization period and the decarburization period are matched by adopting the innovative process, so as to achieve the economic, high-efficiency and deep dephosphorization purposes.
Description
Technical field:
The present invention relates to a kind of converter steelmaking production method, particularly a kind of converter dephosphorization pre-treatment and the method for lacking the slag decarburization.
Background technology:
The invention belongs to the converter steelmaking field, relate generally to converter dephosphorization pre-treatment and converter carbonization treatment.Phosphorus is a kind of easy segregation element in steel, when phosphorus content in the steel greater than 0.015% the time, the segregation of phosphorus sharply increases, and impels segregation line hardness to increase, simultaneously, phosphorus also worsens welding property, significantly reduces the low-temperature impact toughness of steel, improves the brittle transition temperature of steel.The pipe line steel of present domestic Wide and Thick Slab production field production, ocean platform all need low phosphorus content with steel, oil well pipe steel, low-temperature (low temperature) vessel with steel etc.Along with financial crisis surpasses 5,000 ten thousand tons to the influence of steel industry and China Steel industry production capacity increasing degree for years, under market supply and demand law effect, the production capacity excessively rapid growth must cause the steel industry supplydemand relationship unbalance, has strengthened the market competition risk.If China's steel industry duplicate construction is many and production time comparatively concentrates production capacity to discharge suddenly at short notice, will cause imbalance between supply and demand to transform, the profit of steel industry is further compressed.Domestic several big steel mill simultaneously will improve the core competitiveness of enterprise, strengthen the part of cost control dynamics as business strategy.Therefore the smelting of economy and high-quality steel becomes the inevitable choice of steel industry.
The nineties in last century, Kobe Steel, Nippon Steel, Sumitomo Metal Industries, NKK etc. carried out similar Study on Process one after another, and obtain great economic benefit, the more and more many Steel Plant of Japan begin to adopt this technology in recent years, Wakayama Steel Plant of Sumitomo Metal Industries are at the steelworks of its new reconstruction, special-purpose converter of dephosphorization and decarburization steel-making converter between striding, the difference in workshop are set respectively, dephosphorization and decarburization duration of blast are shortened, realized very low-cost, high efficiency STEELMAKING PRODUCTION.But special-purpose converter of dephosphorization and decarburization steel-making converter need be set respectively.
Tradition three technology of taking off are at first carried out the desiliconization pre-treatment to molten iron, in blast furnace iron outlet groove or iron ladle, torpedo car, carry out, in iron ladle or torpedo car, carry out desulfurization and dephosphorization pre-treatment or dephosphorization and desulfurization processing simultaneously then respectively, again " three take off " back molten iron is carried out few slag blowing at top and bottom combined blown converter at last.The problem that exists based on the technical process of the outer hot metal pretreatment of converter: the molten iron reaction vessel of dephosphorization and desulfurization simultaneously is little, is unfavorable for the carrying out of slag gold reaction; The dynamic conditions of the dephosphorization and desulfurization reaction of metal mixer car is bad, has the dead band; The processing place disperses, and the treatment time is long; The treating processes temperature drop is big, handles the back temperature drop greater than 100 ℃; The heat of Si, P oxidation is not utilized fully; Both thermodynamic conditions of dephosphorization and desulfurization are opposite simultaneously, are unfavorable for degree of depth dephosphorization or deep desulfuration.
Secondly at present domestic also have the converter dephosphorization of employing, decarbonization process, but decarburization time is longer than the dephosphorization cycle far away, causes the dephosphorization decarburization cycle not match.
Summary of the invention:
Purpose of the present invention overcomes the problems referred to above exactly, a kind of converter dephosphorization and few slag decarbonization method are provided, in existing same converter or different converter, carry out dephosphorization, carbonization treatment technology respectively, efficiently solve the dephosphorization decarburization cycle not match, be unfavorable for the problem of degree of depth dephosphorization or deep desulfuration.
The present invention relates to a kind of converter dephosphorization pre-treatment and the method for lacking the slag decarburization for achieving the above object, is processing vessel with the converter with top and bottom complex blowing function, adopts argon bottom-blowing, nitrogen, and the technology of top blast oxygen, few slag decarburization is characterized by:
(1) in same converter, carries out being blended into again after dephosphorization taps a blast furnace then and carry out decarburization in this converter, or in a converter, carry out dephosphorization and in the another one converter, carry out decarburization then;
(2) adopt dephosphorized slag, decarbonized slag to form by dephosphorization slag system A, C and decarburization slag system B respectively, also can A, B mix use simultaneously; The main composition mass percent of slag system A is: CaO35%-60%, FeO5%-25%, SiO
25%-15%, MgO5%-10%, CaF
2≤ 5%, it is CaO45%-55%, FeO15%-25%, SiO that slag system B forms mass percent
25%-15%, MgO5%-10%, CaF
2≤ 10%, the main chemical compositions mass percent of C is CaO70%-90%, SiO
2+ CaF
2+ MgO≤30%;
(3) dephosphorization phase end temp is at 1350 ℃-1400 ℃; The carbon period end temp is at 1650 ℃-1750 ℃;
(4) top blast oxygen supply gas intensity 1.2-1.5Nm
3/ min.t;
(5) bottom gas-feeding: to top blast oxygen supply 70%, bottom blowing is for nitrogen intensity 0.03-0.3Nm
3/ min.t; Back top blast oxygen supply 30%, bottom blowing is for argon intensity 0.03-0.3Nm
3/ min.t, during top blast oxygen supply 30%-60% in, adopt low air supply intensity, other times adopt high air supply intensity;
(6) require the converter molten iron temperature to be higher than 1250 ℃, molten iron [Si] content is below 0.60%;
(7) the ore add-on is at 20kg/t-40kg/t the dephosphorization phase, and scrap ratio is at 5%-9%;
(8) dephosphorization phase end carbon content is controlled at 2.8%-3.2%.
In the time of in same converter, dephosphorization phase molten iron is poured out, be poured in the slag ladle after staying slag in stove, carry out carbonization treatment in the same stove in that molten iron is returned then; In the time of in different converters, after molten iron is poured out with the dephosphorization phase, be blended into another block converter and carry out carbonization treatment.
The use that mixes of high CaO content and low CaO content in A and the C chemical ingredients, mixing quality than ratio according to mass ratio 1: 3-1: 4, in converter, mix naturally.
Calcium oxide can also can be white lime and light dolomite mixture from white lime, and the mixing quality ratio is according to 4: 1-2: 1.
The dephosphorization phase finishes basicity of slag≤3, and the lime add-on reduces 18-20kg/t.
Decarburization slag system B changes A after treatment into, and its manufacture craft can adopt adds nitrogen flushing after the transformation of the way agent contain CaO, and nitrogen flushing intensity is at 3-5Nm
3/ min.t, and pour out the shoddye that contains FeO, make it to change into viscosity height, low-melting A slag system.
Oxygen supply intensity when carbon period adopts conventional the smelting satisfies decarburization cycle and dephosphorization cycle to be complementary.
The invention has the beneficial effects as follows: adopt to efficiently solve the dephosphorization decarburization cycle after this method and do not match, the problem that is unfavorable for degree of depth dephosphorization or deep desulfuration, the half steel phosphorus content is at 0.012%-0.015%, and the carbon period dephosphorization rate is 80%, and the converter terminal phosphorus content is at 0.003%-0.004%.
Embodiment:
The present invention adopts decarburization tapping back slag to stay in the stove, and carries out slag splashing, behind slag adding C, slag is left to next stove.The dephosphorization phase is adopted low oxygen supply intensity, adopts the ore slag of ton steel 20kg-40kg, and the dephosphorization phase finishes carbon content and is controlled at 2.8%-3.2%, reaches the effect that dephosphorization cycle and decarburization cycle are complementary.Molten iron temperature is controlled at about 1250 ℃-1350 ℃, and molten iron silicon content is controlled at 0.30-0.60%, and about 108 tons of total molten iron Intake Quantitys are about frivolous material steel scrap 5-9 ton.The dephosphorization phase adds lime 2-6 ton, and basicity of slag is controlled at 1.8-3.0, and the dephosphorization end temp is controlled at about 1350 ℃-1400 ℃, 1.2 meters-1.5 meters of oxygen lance positions, oxygen flow 9000m
3/ h smelts the 3-4 branch, after the stove that falls goes out half steel, is blended into converter again, and carbon period adds 2 tons of limes, and control basicity is more than 5.0, and oxygen flow remains on 22000m
3/ h, the argon bottom-blowing flow remains on 400m
3/ h-1200m
3/ h, the catch carbon temperature adopts this technology to save about lime ton steel 20kg/t between 1660-1680 ℃, and converter terminal molten steel phosphorus is controlled at level about 40ppm.
Embodiment: this test requirements document Intake Quantity about 100 tons, frivolous steel scrap 7-8 ton, scrap ratio 6-8% because frivolous material is limited, part has adopted rolls plate and cuts edge; The molten iron situation is as shown in the table.
Table 1 hot metal composition (mass percent)
| Heat | C (％) | Si (％) | Mn(％) | P (％) | Go into the stove molten iron temperature (℃) |
| 1 | 4.11 | 0.33 | 0.13 | 0.090 | 1314 |
| 2 | 4.26 | 0.58 | 0.12 | 0.093 | 1346 |
Table 2 dephosphorization phase auxiliary material add-on (ton)
Test was adopted duration of blast 9-10 minute, and oxygen-supplying amount is about 1.30-1.42, and following table is result after the dephosphorization pre-treatment.
Table 3 dephosphorization finishes back hot metal composition (mass percent)
Table 4 dephosphorization finishes back A slag system ingredient (mass percent)
| Heat | TFe(％) | FeO(％) | Fe 2O 3(％) | SiO 2(％) | CaO(％) | ?MgO(％) | P 2O 5(％) | R |
| 1 | 19.4 | 18.82 | 6.83 | 17.93 | 35.5 | ?11.41 | 1.96 | 1.98 |
| 2 | 8.93 | 8.73 | 3.07 | 18.63 | 47.95 | ?8.46 | 1.88 | 2.57 |
Table 5 carbon period finishes back B slag system ingredient (mass percent)
| Heat | CaO(％) | SiO2(％) | MgO(％) | Tfe(％) | FeO(％) | MnO(％) | P 2O 5(％) | S(％) | R |
| 1 | 40.4 | 7.9 | 10.2 | 35.0 | 45.0 | 3.5 | 1.3 | 0.06 | 5.1 |
| 2 | 44.0 | 10.29 | 8.5 | 31.3 | 40.3 | 3.0 | 0.9 | 0.06 | 4.3 |
Carbon period adopts flow 22000Nm
3/ min.t, duration of blast 8-9 minute, decarburization cycle and dephosphorization cycle mated fully.
Adopt the advantage of this technology as follows:
1, lime consumption reduces
Than common process, lime consumption reduces nearly 1/4th.
2, the cycle mates more
Two slag cycles are more than 45min, under the normal circumstances, converter is the smelting cycle restricted link, problem at status of equipment and smelting cycle coupling, we adopt the mode of a dephosphorization stove for a decarburization stove, are similar to Wakayama system iron institute of Sumitomo Metal Industries, and normal process is adopted in an other converter, dephosphorization stove, decarburization stove cycle all were controlled at about 22 minutes, and two slag times of smelting cycle are short.
3, phosphorus content is lower after the end of dephosphorization phase
Traditional double slag half steel finishes the back phosphorus content about 0.035-0.045%, adopts this technology half steel phosphorus content about 0.012%-0.015%, and the carbon period dephosphorization rate is about 80%, and the converter terminal phosphorus content is about 0.003%-0.004%.
Claims (6)
1. the method for a converter dephosphorization pre-treatment and few slag decarburization is a processing vessel with the converter with top and bottom complex blowing function, adopts argon bottom-blowing, nitrogen, and the technology of top blast oxygen, few slag decarburization is characterized by:
(1) in same converter, carries out being blended into again after dephosphorization taps a blast furnace then and carry out decarburization in this converter, or in a converter, carry out dephosphorization and in the another one converter, carry out decarburization then;
(2) adopt dephosphorized slag, decarbonized slag to be made up of dephosphorization slag system A, C and decarburization slag system B respectively, perhaps A, B mix use simultaneously; The main composition mass percent of slag system A is: CaO35%-60%, FeO5%-25%, SiO
25%-15%, MgO5%-10%, CaF
2≤ 5%, it is CaO45%-55%, FeO15%-25%, SiO that slag system B forms mass percent
25%-15%, MgO5%-10%, CaF
2≤ 10%, the main chemical compositions mass percent of C is CaO70%-90%, SiO
2+ CaF
2+ MgO≤30%;
(3) dephosphorization phase end temp is at 1350 ℃-1400 ℃; The carbon period end temp is at 1650 ℃-1750 ℃;
(4) top blast oxygen supply gas intensity 1.2-1.5Nm
3/ min.t;
(5) bottom gas-feeding: to top blast oxygen supply 70%, bottom blowing is for nitrogen intensity 0.03-0.3Nm
3/ min.t; Back top blast oxygen supply 30%, bottom blowing is for argon intensity 0.03-0.3Nm
3/ min.t, during top blast oxygen supply 30%-60% in, adopt low air supply intensity, other times adopt high air supply intensity;
(6) require the converter molten iron temperature to be higher than 1250 ℃, molten iron [Si] content is below 0.60%;
(7) the ore add-on is more than 3kg/t the dephosphorization phase, and scrap ratio is below 7%;
(8) the dephosphorization phase finishes carbon content to be controlled at the quality percentage composition is 2.8%-3.2%.
2. according to the described method of claim 1, it is characterized in that: with one heat steel moisture stage processing, in same converter or different converter, handle respectively, in the time of in same converter, dephosphorization phase molten iron is poured out, be poured in the slag ladle after staying slag in stove, and then molten iron returned carry out carbonization treatment in the same stove; In the time of in different converters, after molten iron is poured out with the dephosphorization phase, be blended into another block converter and carry out carbonization treatment.
3. method according to claim 1 is characterized in that: the use that mixes of high CaO content and low CaO content in A and the C chemical ingredients, blending ratio are according to mass ratio 1: 3-1: 4, in converter, mix naturally.
4. according to claim 1 or 3 described methods, calcium oxide is from white lime or white lime and light dolomite mixture, and blending ratio is according to mass percent 4: 1-2: 1.
5. method according to claim 1 is characterized in that: decarburization slag system B changes A after treatment into, and its manufacture craft can adopt adds nitrogen flushing after the transformation of the way agent contain CaO, and nitrogen flushing intensity is at 3-5Nm
3/ min.t, and pour out the shoddye that contains FeO, make it to change into viscosity height, low-melting A slag system.
6. method according to claim 1 is characterized in that: the oxygen supply intensity when carbon period adopts conventional the smelting, satisfy decarburization cycle and dephosphorization cycle to be complementary.
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| CN101691622B true CN101691622B (en) | 2011-01-26 |
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102010933A (en) * | 2010-11-05 | 2011-04-13 | 钢铁研究总院 | Molten iron dephosphorization agent manufactured by using converter dry-method dust-removal ash as raw material |
| CN102212640B (en) * | 2011-06-01 | 2013-11-27 | 首钢总公司 | Convertor steelmaking method capable of reducing slag quantity |
| CN102212643B (en) * | 2011-06-03 | 2014-04-30 | 首钢总公司 | Converter less-slag smelting process |
| CN102416404B (en) * | 2011-09-21 | 2014-05-28 | 首钢总公司 | Method for producing cold-rolled steel strips |
| CN102382930A (en) * | 2011-11-13 | 2012-03-21 | 首钢总公司 | Converter steelmaking technology |
| CN102505062B (en) * | 2011-12-31 | 2013-04-24 | 钢铁研究总院 | Converter rapid desilicification and dephosphorization pretreatment method |
| TW201243057A (en) * | 2012-07-12 | 2012-11-01 | Welder Ind Co Ltd | Dephosphorization agent for steelmaking and steelmaking method for reducing phosphorous content |
| CN104263875B (en) * | 2014-09-15 | 2016-03-02 | 首钢总公司 | A kind of top blown converter adopts high phosphorus hot metal to produce the dephosphorizing method of alloy bonding wire steel |
| CN104232841A (en) * | 2014-09-28 | 2014-12-24 | 四川德胜集团钒钛有限公司 | Dephosphorizing slagging agent and preparation method thereof |
| CN105861775B (en) * | 2015-01-23 | 2018-04-03 | 鞍钢股份有限公司 | Smelting process method of high-nickel-content ultra-low-phosphorus steel |
| CN106148632B (en) * | 2015-03-28 | 2018-01-05 | 鞍钢股份有限公司 | Economical converter less-slag combined blowing smelting process |
| CN107760823B (en) * | 2017-11-22 | 2023-04-25 | 北京科技大学 | Quasi-continuous steelmaking system and process of full scrap steel electric arc furnace |
| CN114807498B (en) * | 2022-05-20 | 2024-01-02 | 钢铁研究总院有限公司 | Efficient dephosphorization and decarbonization method for converter |
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Address after: 100041 Shijingshan Road, Shijingshan District, Shijingshan District, Beijing Patentee after: Shougang Group Co. Ltd. Address before: 100041 Shijingshan Road, Shijingshan District, Shijingshan District, Beijing Patentee before: Capital Iron & Steel General Company |
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