CN1023410C - Production of ingot iron with solid decarbonising pig iron adn remelting in electric furnace - Google Patents
Production of ingot iron with solid decarbonising pig iron adn remelting in electric furnace Download PDFInfo
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- CN1023410C CN1023410C CN 89109527 CN89109527A CN1023410C CN 1023410 C CN1023410 C CN 1023410C CN 89109527 CN89109527 CN 89109527 CN 89109527 A CN89109527 A CN 89109527A CN 1023410 C CN1023410 C CN 1023410C
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- iron
- electric furnace
- decarburization
- furnace
- refining
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Abstract
The present invention relates to a technology for decarbonizing solid pig-iron and producing Armco iron in an electric furnace by way of remelting. In the technology, granulated iron is loaded in a rotary kiln, proper oxygen which is returned and replenished by combustion products is used as the oxidant for auxiliary heating together with coal gas that is properly supplemented, and the carbon content of granular iron is lower than 0.3% after the granular iron is roasted and decarburized for 3 to 5 hours. Low-carbon granular iron is then melted after loaded into a sensitive or plasma electric furnace, a uniform iron oxide layer is formed after the granular iron is oxidized by way of roasting, a secondary decarbonizing refinement is carried out, and common or high purity Armco iron is refined after 1 to 2 hours. For a newly established factory which annually produces two thousand tons of Armco iron, only one million yuan is used as the construction investment, and the invested capital can be recovered in half year.
Description
The invention belongs to refining of metal or remelting.
The manufacture pure iron mainly is to use electric arc furnace at present, also uses the oxygen top and bottom combined blown converter abroad.Be characterized in that liquid metal carries out the metallurgy industry pure iron.The electric furnace raw material is a low-carbon (LC) high-quality steel scrap, and composition is C＜0.55%, P＜0.45%, S＜0.03%, Ni＜0.02%, Cr＜0.15%.Oxygen Jet Steel is returned in employing, and with higher steel-making temperature, bigger oxygen supply intensity removes carbon in the iron liquid, reaches below the carbon content specification of technically pure iron, after the tapping of reduction back.Because the decarburization of iron liquid needs high temperature, so electrosmelting technically pure iron smelting cycle is long, power consumption is big, lining life is low, cost is high.And can't avoid entering of element such as Ni, Cr in the steel scrap, its product purity is not high, be difficult to smelt 99.9% technically pure iron.
The thirties, Sweden once worked out RK method production Low Carbon Iron as the raw material of smelting special steel, this method with rotary kiln oxidizing roasting small grain size granulated iron, can be pig iron depth decarburization.China studies have shown that with the granulated iron carbon rejection processes can produce 3-12mm carbon containing 1% following granulated iron, and as the Electric furnace steel making raw material, this method certain practical significance is arranged, but economic benefit is not high when the steel scrap shortage.
It is slow to the objective of the invention is to overcome in the electric furnace liquid pig iron decarbonization rate, thereby the big shortcoming of productivity low power consumption, changes existing electric arc furnace smelting technically pure iron technology.And adopt a decarburization of granulated iron solid phase and the secondary liquid decarburization of decarburization abrasive grit and refining to remove the method for other element, produce high-purity technically pure iron.
It is P＜0.08% that the present invention adopts composition; S＜0.05%; and do not contain other alloying element (as Cr; Ni, Hn etc.) regular pig is raw material, earlier liquid pig iron is become the granulated iron of 0-2mm, roasting under oxidizing atmosphere to a certain degree in rotary kiln again with the high pressure water punching out; carry out solid-state pig iron decarburization; pig iron carbon content is reduced to below 0.3%, and the Si in the pig iron, S, P also partial oxidation remove, and the abrasive grit surface generates small amount of Fe O layer.With this decarburization granulated iron as the electric furnace raw material; pack into induction furnace or plasma electric stove; and to make basicity with addition of coal be that the slag of 2.5-3.5 carries out refining, utilizes the equally distributed FeO in abrasive grit top layer as oxygenant, further depth decarburization, desiliconization, dephosphorization and desulfurization.Make C＜0.025%, Si＜0.02%, P＜0.015%, S＜0.015%, and the technically pure iron of iron content＞99% meets the DTI-DT4 national standard.Low-phosphorous and low-alloy content high duty pig iron is made raw material, strict controlled oxidation sinter process, just can be produced carbon containing C＜0.01%, the high-purity technically pure iron of iron content Fe＞99.9% or meet little carbon-based industry pure iron (C＜0.015%) of GB DTO as selected low-sulfur.
The present invention adopts two kinds of technical process according to oxidizing gas medium difference.The first pass (see figure 1) comprises the 1-blast furnace, 2-blast furnace gas, 3-crane, 4-water pump, 5-granulation pond, 6-belt conveyor, 7-granulated iron jar, 8-rotary kiln, 9-decarburization grain iron, 10-electric refining furnaces, 11-technically pure iron.It is the energy that this flow process adopts blast furnace gas, and the waste gas that blast furnace gas control burning generates carries out the once oxidation decarburization as oxygenant in rotary kiln.Pack into then and carry out secondary decarburization and refining in the induction furnace.900-1100 ℃ of kiln operation temperature, filling ratio 20-30%, one time decarburization time 3-5 hour, it was 80-90% that solid takes off the charcoal rate, elements such as the P in the pig iron, S also part remove.Secondary refining electric-furnace slag basicity is 2.5-3.5, and the electric furnace refining cycle is 2 hours.Technically pure iron per ton consumes blast furnace gas 200m
3, power consumption 800 degree.This flow process energy sources is extensively cheap, be suitable for the small blast furnace product extends.The second flow process (see figure 2) comprises the 6-belt conveyor, 7-granulated iron jar, 8-rotary kiln, 9-decarburization abrasive grit, 10-electric refining furnaces.The 11-technically pure iron, the 12-water seal, the 13-rotary kiln returns gas.Advance a decarburization roasting with returning gas and oxygen as oxygenant in the rotary kiln, or control incendiary waste gas with blast furnace gas and do oxygenant roasting decarburization, utilize the exothermic effect of reaction to provide production process required most of heat, insufficient Btu utilization a small amount of coal gas that burns replenishes.Utilize the equally distributed feature of iron oxide layer of granulated iron oxidizing roasting process; in plasma body electric furnace or induction furnace, carry out secondary granulated iron depth decarburization and refining; can make the general industry pure iron of iron content 99%, also can produce and contain high-purity technically pure iron of 99.9%.The granulated iron granularity is 0-2mm, and the oxidizing roasting gaseous constituent is 1-3%O
2, 91-100%CO
2, 0-10%CO; When using blast furnace gas, the gas composition of roasting is 23-26%CO
2, 3%O
2, 72-78%N
2, 900 °-1100 ℃ of kiln operation temperature, filling ratio 20-30%, solid take off 3-5 hour charcoal time, and the solid oxidation carbon-drop rate is 80-90%, and elements such as the P in the pig iron, S also part remove.
Above-mentioned pig iron decarburization grain iron at induction furnace or plasma-arc remelting, carry out the refining of decarburization grain iron, basicity of slag is 2.5-3.5, the induction furnace refining time is 2 hours, plasma heating furnace only 1 hour, the secondary decarburization rate reaches more than 60%, and elements such as P, S, Si are removed to below 0.02%, reach the chemical ingredients of high-purity technically pure iron requirement.（Fe＞99.9%）。Consumption indicators is for returning waste gas 240-720Nm
3/ t, flow of oxygen are 60-80Nm
3/ t, postcombustion coal gas is about 200Nm
3Other coal gas of the blast furnace gas of/t or suitable calorific value.Blow-on for the first time can supply carbon dioxide 5Nm earlier
3/ t is after the normal operation, by These parameters supply oxygen and coal gas.Second flow process is suitable for not relying on the production of high-purity technically pure iron that iron work founds the factory.
Process characteristic of the present invention:
1. energy consumption of unit product is little
Because the reaction total effect is a self-heating procedure, so the production process energy consumption is very low.According to Theoretical Calculation, decarburization generates CO reaction liberated heat, can satisfy decarburization operation geothermal flow needs; (formula is seen the literary composition back)
This surplus heat can satisfy 21.4% thermosteresis, and is reasonable as operating duty, then can not consume additional fuel to large-sized rotary kiln decarburization roasting, and this is confirmed by practice.And small-sized rotary kiln is also only consumed the fuel gas of (40000Cal/t) on a small quantity.
It is about 1% to contain Si in the decarburization abrasive grit, and following thermopositive reaction: Si+2FeO=SiO takes place in electric furnace
2+ 2Fe+75860Cal/mol
Can make technically pure iron refining power consumption per ton save 30 degree.
2. product purity height
(a) but the technological process depth decarburization, but general decarburization to C＜0.02%, but decarburization in case of necessity is to C＜0.01%.
(b) decarburization grain iron when electric furnace refining by following reaction deep desilication:
Si can be removed to below 0.02%.
(c) but dephosphorization 30% in the oxidizing roasting process, the electric furnace refining dephosphorization rate is more than 90%.Thereby when using the general pig iron, but below the dephosphorization to 0.015% as raw material.Desulfurization in like manner also can be arrived below 0.015%.
(d) alloying element
Do not have difficult reduction elements such as Cr, Al in the base iron, Ni, Co, Mn etc. easily reduction elements can avoid entering technically pure iron by selecting the pig iron.
So high-purity technically pure iron of this technology energy production iron content 99.9%.
3. raw material is easily asked
The pig iron composition that this technology is used only requires to meet national standard, and most of little iron works can provide.
4. economic benefit height
1500 yuan of this explained hereafter technically pure iron costs per ton, and the market price is 2700 yuan, product per ton has 1200 yuan of economic benefits (seeing Table 1).
5. industrial scale is flexible, and initial cost is little
Can build little factory, and initial cost is few, instant effect as annual output 500-1000t.Produce 2000 tons of factories per year and only need 1,000,000 yuan of capital costs, can in half a year, recoup capital outlay.Being suitable for little iron work product extends.
Calculate in view of the above:
Every kg pig iron decarburization 3% can produce heat+1015740J
Every kg pig iron is heated to 1000 ℃ of consumption of calorie-689700J
Waste gas is taken away heat-107008J
Surplus heat+217360J
The pricing of table 1 solid carbon rejection processes manufacture pure iron
Unit consumption unit price cost
The preface item remark
Unit parameter unit price (unit)
1.4 yuan/ton 780 1092 of 1 base iron tons/ton
0.03 yuan/ton 37 1.11 of 2 auxiliary material lime ton/ton
Power consumption 116
3 electric degrees/800 yuan/degree 0.12 96 of ton
Coal gas m
3200 yuan/m of/ton
30.10 20
4 wages 54
5 depreciations 25 are by 5% ratio of depreciation
6 working expenses 85
7 costs 1373
Claims (1)
1, high-purity industrial iron technology is produced in pig iron solid decarburization and electric furnace remelting decarburization; less than 0.08%, sulfur-bearing is less than 0.05% the blast-melted granulated iron made from phosphorous, inserts rotary kiln and carries out solid and take off charcoal; it is characterized in that granulated iron granularity 0～2mm, the oxidizing roasting gaseous constituent is 1～3%O
2, 91～100%CO
2, 0～10%CO, or when using blast furnace gas, the gas composition of roasting is 23～36%CO
2, 3%O
2, 72～78%N
2900～1100 ℃ of kiln operation temperature, filling ratio 20～30%, solid phase is taken off 3～5 hours charcoal time, carries out solid phase and takes off charcoal, then, take off the refining of carbon granule iron with induction furnace or plasma body electric furnace, basicity of slag 2.5～3.5, if 2 hours induction furnace refining time is with then refining 1 hour of plasma heating furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89109527 CN1023410C (en) | 1989-12-28 | 1989-12-28 | Production of ingot iron with solid decarbonising pig iron adn remelting in electric furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 89109527 CN1023410C (en) | 1989-12-28 | 1989-12-28 | Production of ingot iron with solid decarbonising pig iron adn remelting in electric furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1052900A CN1052900A (en) | 1991-07-10 |
| CN1023410C true CN1023410C (en) | 1994-01-05 |
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ID=4858056
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 89109527 Expired - Fee Related CN1023410C (en) | 1989-12-28 | 1989-12-28 | Production of ingot iron with solid decarbonising pig iron adn remelting in electric furnace |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1023410C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1041113C (en) * | 1994-09-02 | 1998-12-09 | 冶金工业部钢铁研究总院 | Method and apparatus for decarbonizing granular iron of blast furnace |
| US6749661B2 (en) * | 2000-02-10 | 2004-06-15 | Process Technology International, Inc. | Method for melting and decarburization of iron carbon melts |
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1989
- 1989-12-28 CN CN 89109527 patent/CN1023410C/en not_active Expired - Fee Related
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| Publication number | Publication date |
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| CN1052900A (en) | 1991-07-10 |
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