CN101948979B - Method for producing industrial pure iron - Google Patents

Method for producing industrial pure iron Download PDF

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Publication number
CN101948979B
CN101948979B CN2009101585505A CN200910158550A CN101948979B CN 101948979 B CN101948979 B CN 101948979B CN 2009101585505 A CN2009101585505 A CN 2009101585505A CN 200910158550 A CN200910158550 A CN 200910158550A CN 101948979 B CN101948979 B CN 101948979B
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China
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weight
molten steel
oxygen level
aluminium
oxygen
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CN101948979A (en
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刘明
邓通武
李军
熊元波
杨星地
陈小龙
蒲学坤
江南红
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Pangang Group Steel Vanadium and Titanium Co Ltd
Pangang Group Research Institute Co Ltd
Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Steel Vanadium and Titanium Co Ltd
Pangang Group Research Institute Co Ltd
Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Abstract

The invention relates to a method for producing industrial pure iron, which comprises the following steps: converter primary smelting: carrying out primary smelting in a converter to convert molten iron to molten steel; ladle deoxidation: tapping off the molten steel into a ladle from the converter, and adding aluminum to the ladle to enable the oxygen content of the molten steel to be more than 0.04-0.06wt%; heating deoxidation: heating the molten steel subject to the ladle deoxidation to 1620-1660 DEG C, and adding aluminum to the ladle to enable the oxygen content of the molten steel to be 0.03-0.04wt%; and vacuum degasification: degassing the molten steel subject to the heating deoxidation in vacuum until the carbon content of the molten steel is below 0.03wt%, and then adding aluminum to enable the acid-soluble aluminum content of the molten steel to be 0.02-0.05wt%. By using the method, more than 120 tons of industrial pure iron can be produced in every batch, and the carbon content of the produced industrial pure iron can be below 0.03 wt%.

Description

A kind of method of manufacture pure iron
Technical field
The present invention relates to a kind of method of manufacture pure iron.
Background technology
Technically pure iron is a kind of of steel, and its main chemical constitution is: iron level 99.5-99.9 weight %, below the carbon content 0.04 weight %, below 0.15 weight %, the content of p and s is respectively below 0.015 weight % respectively for the content of silicon and manganese.Technically pure iron is not real pure iron in fact also, so claim that this a kind of steel that approaches pure iron is a technically pure iron.The technically pure iron particularly soft, good toughness has electromagnetic performance preferably, so often be used as draw piece and electromagnetic material.Technically pure iron also can be used as the raw material of heavily fused gold, vacuum induction furnace and Ultralow Carbon Stainless Steel, so technically pure iron also can be pure iron as raw material.
Technically pure iron generally adopts the smelting mode of electric arc furnace (or induction furnace) or electric arc furnace (or induction furnace)+vacuum oven to produce.For example, certain Iron And Steel Plant of Jiangsu metallurgical (1996 5 phases, 15-16 page or leaf) report have adopted the method for the direct metallurgy industry pure iron of electric arc furnace, can the production carbon content less than the technically pure iron of 0.04 weight %; Disclose among the CN 101078033A and a kind ofly made raw material, be employed in vacuum system and carry out oxygen blast dephosphorization under the vacuum condition, vacuum carbon deoxidization, add the method that slag charge BOTTOM ARGON BLOWING desulfurizing and refining is produced pure iron through VOD (vacuum-oxygen decarbonizing) refining furnace with steel scrap; CN 1023410C also discloses and a kind ofly in rotary kiln, the blast-melted abrasive grit that makes has been carried out solid and take off charcoal, then with the method for induction furnace or plasma body electric furnace remelting refining manufacture pure iron.
There is a common shortcoming in the method for above-mentioned three kinds of manufacture pure iron, promptly all adopts electric arc furnace (or induction furnace) technology, generally; The amount of the technically pure iron of the every stove production of electric arc furnace is about the 5-60 ton; And induction furnace is below 1 ton, and throughput is little, can not satisfy industrial requirement.
Summary of the invention
The objective of the invention is to overcome the little shortcoming of method throughput of manufacture pure iron in the prior art, the method for the big manufacture pure iron of a kind of throughput is provided.
The invention provides a kind of method of manufacture pure iron, this method may further comprise the steps: converter is just refined, and refining makes molten iron be converted into molten steel to use converter to carry out just; Ladle deoxidation is tapped the molten steel in the converter in the ladle, and in ladle, is added aluminium, makes oxygen level in the molten steel for greater than 0.04 weight % to 0.06 weight %; The heating deoxidation is heated to 1620-1660 ℃ with the molten steel behind the ladle deoxidation, in ladle, adds aluminium, makes the oxygen level in the molten steel reach 0.03-0.04 weight %; Vacuum outgas outgases to the molten steel after the heating deoxidation under vacuum condition, and the carbon content to molten steel reaches below the 0.03 weight %, adds aluminium again and makes the acid-soluble aluminum content in the molten steel reach 0.02-0.05 weight %.
Converter is the very high steelmaking equipment of operating rate, is one of best equipment of decarburization.Top-blown oxygen converter is blown into pure oxygen, and only the time about 15 minutes just can be with the level of the molten steel decarburization about carbon containing 4.5 weight % to about 0.05 weight %; If but proceed the oxygen decarburization operation this moment; The oxidized speed of iron in the converter in the molten iron phenomenon of the oxidized scaling loss of a large amount of iron can occur much larger than the oxidized speed of carbon.Generally, the limit of converter decarburization is about 0.03 weight %, and when carbon reached the 0.03 weight % left and right sides, continuing oxygen blast can not decarburization, only can make a large amount of oxidation of iron.Therefore, use converter production carbon content very low less than the success ratio of the technically pure iron of 0.04 weight %, even case of successful is arranged, the carbon content of the finished product also can only can't reach the level of 0.02 weight % between 0.03-0.04 weight %.
Contriver of the present invention is through a large amount of discovering: the technology of using " converter is just refined-ladle deoxidation-heating deoxidation-vacuum outgas " is manufacture pure iron on a large scale not only; And the technically pure iron that makes can to reach carbon content be the level below the 0.03 weight %; This be because: the oxygen level of the molten steel before vacuum-treat is 0.03-0.04 weight %; And carbon content is 0.03-0.05 weight %; Oxygen under vacuum condition in the molten steel and the carbon generation carbon monoxide that reacts removes carbon monoxide through vacuum apparatus, can make the carbon content in the molten steel reduce 0.02-0.03 weight % like this; Thereby reach the level below the 0.03 weight %, reach the requirement of technically pure iron carbon content.For the oxygen of remaining 0.01-0.02 weight % in the molten steel,, make the acid in the industrial molten iron dissolve level and whole removal that aluminium reaches 0.02-0.05 weight %, thereby avoided in castingprocesses, overflowing gas through after vacuum outgas, adding aluminium.
The method of manufacture pure iron of the present invention is through using the technology of " converter is just refined-ladle deoxidation-heating deoxidation-vacuum outgas "; Every stove can be produced and surpass 120 tons of technically pure irons, and the technically pure iron that makes can to reach carbon content be the level below the 0.03 weight %.
Embodiment
The method of manufacture pure iron provided by the invention may further comprise the steps: converter is just refined, and refining makes molten iron be converted into molten steel to use converter to carry out just; Ladle deoxidation is tapped the molten steel in the converter in the ladle, and in ladle, is added aluminium, makes oxygen level in the molten steel for greater than 0.04 weight % to 0.06 weight %; The heating deoxidation is heated to 1620-1660 ℃ with the molten steel behind the ladle deoxidation, in ladle, adds aluminium, makes the oxygen level in the molten steel reach 0.03-0.04 weight %; Vacuum outgas outgases to the molten steel after the heating deoxidation under vacuum condition, and the carbon content to molten steel reaches below the 0.03 weight %, adds aluminium again and makes the acid-soluble aluminum content in the molten steel reach 0.02-0.05 weight %.
According to method provided by the invention, wherein, what said converter refined just that step can be for routine utilizes the process of top-blown oxygen converter by the molten iron smelting molten steel; For example, this step can comprise molten iron is joined in the converter, through oxygen rifle oxygen blast gas in converter; The temperature of molten iron can be 1400-1700 ℃ during oxygen blast gas, is preferably 1500-1650 ℃, and the time of oxygen blast gas can be 8-25 minute; Be preferably 10-20 minute; More preferably 12-15 minute, the amount of oxygen blast gas made the carbon content in the molten iron be not more than 0.05 weight %, thereby is converted into molten steel.Generally speaking, carbon content is 0.03-0.05 weight % in the molten steel that obtains.The method of wherein measuring the carbon content in the molten iron is conventionally known to one of skill in the art, for example, can use the method for GB/T223 regulation to record.
Wherein, Said molten iron can be smelted the molten iron that obtains by iron ore for any use blast furnace, typically mainly consisting of of molten iron: the phosphorus of the silicon of the carbon of 3.5-4.5 weight %, 0.15-0.3 weight %, the manganese of 0.2-0.5 weight %, 0.06-0.08 weight %, the sulphur of 0.005-0.01 weight % and the iron of 93-96.5 weight %.
According to method provided by the invention; Wherein, In said ladle deoxidation step, the temperature of molten steel can be 1650-1750 ℃ when tapping the molten steel in the converter in the ladle, is preferably 1670-1700 ℃; Under this preferred temperature, more help the Control for Oxygen Content in the molten steel in 0.04-0.06 weight % scope.In order not make in the molten steel behind the ladle deoxidation oxygen level fall too lowly, be unfavorable for the decarburization of follow-up Vacuum Degassing Process, the add-on of aluminium is wanted strict control in the ladle deoxidation process, and the add-on of aluminium is rather few not many.To achieve these goals, contriver of the present invention gropes to sum up through test of many times, in said ladle deoxidation step; With respect to molten iron per ton; The amount 0.3-0.4 kilogram of the aluminium that in ladle, adds, in this case, the oxygen level behind the ladle deoxidation in the molten steel generally is not less than 0.06 weight %.In order to control behind the ladle deoxidation oxygen level in the molten steel in greater than 0.04 weight % to 0.06 weight % scope; Can measure the oxygen level in the molten steel with apparatus for determination of oxygen after adding aluminium; If the oxygen level that records is higher than 0.06 weight %; Then need continue to add aluminium, with respect to molten iron per ton, the amount of the aluminium that adds again is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1 is kilogram to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2.5 kilogram; Wherein, said desire control oxygen level is 0.03-0.05 weight %.In fact the amount of the above-mentioned aluminium that adds again is equivalent to: with respect to molten iron per ton, and the oxygen of every minimizing 0.0001 weight %, the amount of the aluminium that in ladle, adds again is the 1-2.5 kilogram.Wherein, said desire control oxygen level can be set arbitrarily in the scope of 0.03-0.05 weight %.Generally speaking; After adding the aluminium that calculates according to the method described above; The oxygen level that actual oxygen content in the molten steel promptly records is generally greater than above-mentioned desire control oxygen level; Can guarantee effectively that like this oxygen level in the molten steel behind the ladle deoxidation can not fall too lowly, guaranteed decarburization effectively in the follow-up Vacuum Degassing Process, thereby carbon content be lower than 0.03 weight % in the technically pure iron that guarantees to make.
Under the preferable case; In order to control the oxygen level in the molten steel more accurately; In said ladle deoxidation step, with respect to molten iron per ton, the amount of the aluminium that adds again is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1.5 are kilogram to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2 kilogram; Wherein, said desire control oxygen level is 0.03-0.04 weight %.
For the ease of understanding the amount of the aluminium that adds again in the above-mentioned ladle deoxidation step; Illustrate as follows: in a concrete embodiment of the present invention at present; With respect to molten iron per ton, the amount of the aluminium that in ladle, adds is 0.33 kilogram, at this moment; The oxygen level of using apparatus for determination of oxygen to record in the molten steel is 0.082 weight %; Desire control oxygen level is decided to be 0.04 weight %, and the amount of the aluminium that then need add with respect to molten iron per ton is: [(0.082-0.04)/0.0001] * 1.5 are to [(0.082-0.04)/0.0001] * 2, i.e. 630-840 kilogram.After adding the aluminium in the above-mentioned weight range, if measure with apparatus for determination of oxygen, the oxygen level in the molten steel generally is higher than 0.04 weight %.
According to method provided by the invention, wherein, in said heating deoxygenation step, can use the equipment of well known to a person skilled in the art, for example LF stove (electric heater unit).In this step, molten steel is heated to the oxygen level of using after 1620-1660 ℃ in the apparatus for determination of oxygen mensuration molten steel.In ladle, add aluminium then; With respect to molten iron per ton; The amount of the aluminium that adds is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1 is kilogram to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2.5 kilogram; Wherein, said desire control oxygen level is 0.03-0.04 weight %.In fact the amount of the above-mentioned aluminium that adds again is equivalent to: with respect to molten iron per ton, and the oxygen of every minimizing 0.0001 weight %, the amount that in ladle, adds aluminium can be the 1-2.5 kilogram.Under the preferable case; In order to control the oxygen level in the molten steel more accurately; In said heating deoxygenation step, with respect to molten iron per ton, the amount of the aluminium that adds again is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1.5 are kilogram to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2 kilogram; Wherein, said desire control oxygen level is 0.03-0.04 weight %.
At this moment, reuse apparatus for determination of oxygen and measure the oxygen level in the molten steel,, then repeat the process of above-mentioned adding aluminium, reach 0.03-0.04 weight % up to the oxygen level that records if oxygen level still is higher than 0.04 weight %.
Need to prove that the purpose that in the step of said ladle deoxidation and heating deoxidation, adds aluminium several times is progressively the actual oxygen content in the molten steel to be controlled to be 0.03-0.04 weight %.Wherein, in the process of ladle deoxidation, because the oxygen level in the molten steel is higher; Be difficult to add the aluminium amount and accurately control oxygen level through control; Therefore, be not lower than 0.03 weight % for the aluminium that guarantees to add can not make oxygen level, the process of twice adding aluminium is " stopping before going too far " all; In the process of heating deoxidation; Oxygen level in the molten steel is less than 0.06 weight %; Can add the aluminium amount through control and more accurately control oxygen level this moment, generally speaking, can the actual oxygen content in the molten steel be dropped to 0.03-0.04 weight % through once adding aluminium.
According to method provided by the invention; Wherein, in said vacuum outgas step, can use the vacuum refinement equipment that well known to a person skilled in the art, for example RH stove (vacuum cycle device); Its vacuum tightness can be 1-500 millibar (mbar); Be preferably 3-150mbar, the time of the degassing can be 2-60 minute, is preferably 3-30 minute.Use the process of the RH stove degassing under same vacuum tightness, to outgas once; For example under 50 millibars vacuum tightness, outgased 10 minutes; Also can under different vacuum tightnesss, outgas repeatedly, for example under 80 millibars vacuum tightness, outgas 5 minutes earlier, under 5 millibars vacuum tightness, outgas 12 minutes again.Through vacuum outgas, carbon and oxygen reaction generation carbon monoxide in the molten steel are overflowed from molten steel, thereby reach the purpose of decarburization.
In order to make the oxygen level in the molten steel reach requirement, the present invention adopts the method that adds aluminium, the form that makes wherein oxygen and aluminium fully be combined into aluminum oxide, thereby the content of reduction active oxygen.Content through limiting the molten aluminium of acid guarantees that the content of active oxygen in the molten steel is enough low.
According to method provided by the invention, wherein, the notion that aluminium is dissolved in said acid is conventionally known to one of skill in the art, that is: the total content of aluminium nitride AlN and pure aluminum in the molten steel.In steelmaking process; The aluminium that in molten steel, adds mainly exists with three kinds of forms: aluminium sesquioxide, aluminium nitride AlN and aluminium simple substance; Wherein, aluminium sesquioxide can get into slag greatly and from molten steel, remove, and aluminium nitride AlN and aluminium simple substance are then stayed the alloying substances that becomes steel in the molten steel.Initial stage in molten steel, adding aluminium mainly generates aluminium sesquioxide, and along with the oxygen in the molten steel is consumed, oxygen level is more and more lower, and the content of aluminium nitride AlN and aluminium simple substance increases gradually.Therefore, have only total content (i.e. the content of aluminium is dissolved in acid) when acquiring a certain degree, could the oxygen level in the molten steel be reduced to the level that in castingprocesses, can not overflow gas (oxygen and/or CO gas) when aluminium nitride AlN and aluminium simple substance.Therefore, method of the present invention also comprises the acid-soluble aluminum content of measuring in the molten steel, and the method for measuring the acid-soluble aluminum content in the molten steel is conventionally known to one of skill in the art, for example, can use the method for GB/T4336 regulation to measure.In the method for the invention, the acid-soluble aluminum content in the molten steel can be preferably 0.03-0.04 weight for 0.02-0.05 weight %.Full aluminium content is meant the total content of the various forms of aluminium that exist in the molten steel.
According to method provided by the invention, wherein, the material that said aluminium general reference can provide pure aluminum not introduce other impurity for molten steel for example, can be in aluminium block, aluminum steel, aluminum shot and the ferroaluminium one or more.Under the preferable case; When and amount adding aluminium higher when liquid steel temperature is big; In molten steel, add aluminium block and/or ferroaluminium, or the amount that add aluminium lower when liquid steel temperature hour adds aluminum steel in molten steel; The method that adds aluminum steel can be used the conventional method in this area, uses feeding wire machine in molten steel, to feed aluminum steel.Before casting, in the process of the acid-soluble aluminum content of adjusting molten steel, preferably in molten steel, add aluminum shot, wherein, the diameter of aluminum shot is preferably the 5-15 millimeter.
The working method of technically pure iron provided by the invention also comprises the molten steel casting that obtains.The method of said casting can be die casting or continuous casting.
Below, will be described in more detail the present invention through embodiment.
Embodiment 1
Present embodiment is used to explain the method for manufacture pure iron provided by the invention.
In 120 tons of converters, add 125 tons of molten iron, be blown into oxygen and carry out converter and just refine, oxygen blast obtains the molten steel that carbon content is 0.04 weight % after finishing, and under 1655 ℃, this molten steel is tapped in the ladle.Wherein, mainly consisting of of molten iron: iron 96.42 weight %, carbon 3.55 weight %, silicon 0.026 weight %, manganese 0.065 weight %, phosphorus 0.039 weight %, sulphur 0.018 weight %, copper 0.016 weight %, nickel 0.018 weight %, chromium 0.020 weight %.Molten iron temperature during oxygen blast gas is 1400-1650 ℃ (be 1400 ℃, oxygen blast is 1650 ℃ after finishing, and is a process that raises gradually) when oxygen blast begins, and the oxygen blown time is 14 minutes, and the oxygen blast total amount is 6766m 3, from the beginning oxygen blast to blowing oxygen quantity be to be blown into 90% of amount of oxygen, the flow of oxygen be 30000 SCMs/hour; Blowing oxygen quantity is after 90%, the flow of oxygen be 20000 SCMs/hour.
In the process of ladle that molten steel is tapped, in ladle, add 40 kilograms of aluminium blocks, molten steel is carried out deoxidation.After the molten steel tapping was accomplished, the oxygen level that the MULPI-LABCELOX apparatus for determination of oxygen that uses Shanghai Ke Hai temperature measurer ltd to produce is measured in the molten steel was 0.085 weight %.Desire control oxygen level in the molten steel is set at 0.040 weight %, uses 420 meters of the aluminum steels (about 84 kilograms) of the WX-4BF feeding wire machine feeding Φ 10mm of Central China, Gongyi, Henan metallurgical equipment factory.
Then, ladle is delivered to furnaceman LF position and heat deoxidation.Use the LF device that the molten steel in the ladle is heated to 1650 ℃, the oxygen level of using above-mentioned apparatus for determination of oxygen to measure in the molten steel is 0.058 weight %.Then the desire control oxygen level in the molten steel is set at 0.032 weight %, uses 210 meters of the aluminum steels (about 42 kilograms) of above-mentioned feeding wire machine feeding Φ 10mm, the oxygen level of using apparatus for determination of oxygen to record in the molten steel is 0.035 weight %.
Then, ladle is delivered to the RH station and carry out vacuum outgas.At first under 100mbar vacuum tightness, outgasing 3 minutes, under the vacuum tightness of 3mbar, outgasing 15 minutes then.After the degassing is accomplished, in ladle, add 60 kilograms of aluminum shots, the weight of measuring molten steel then is 124 tons, and the carbon content in the molten steel is 0.02 weight %, and acid-soluble aluminum content is 0.038 weight %, and oxygen level is 0.0035 weight %.
Then the molten steel that obtains continuous casting on 4 machines, 4 stream arc billet casters is become the continuously cast bloom of 360 * 450 * 6000mm, the tundish temperature of continuous caster is controlled to be 1560 ℃, in the casting cycle; The carbon content of getting steel appearance mensuration molten steel at the continuous casting tundish is 0.02 weight %, and acid-soluble aluminum content is 0.035 weight %, and full aluminium content is 0.045 weight %; Silicone content is 0.005 weight %, and manganese content is 0.03 weight %, and phosphorus content is 0.005 weight %; Sulphur content is 0.015 weight %, and copper content is 0.018 weight %, and nickel content is that 0.02 weight %, chromium content are 0.015 weight %; Iron level has reached the requirement of technically pure iron more than 99.8 weight %.
Embodiment 2
Present embodiment is used to explain the method for manufacture pure iron provided by the invention.
In 120 tons of converters, add 120 tons of molten iron, be blown into oxygen and carry out converter and just refine, oxygen blast obtains the molten steel that carbon content is 0.045 weight % after finishing, and under 1695 ℃, this molten steel is tapped in the ladle.Wherein, mainly consisting of of molten iron: iron 95.17 weight %, carbon 4.45 weight %, silicon 0.080 weight %, manganese 0.084 weight %, phosphorus 0.040 weight %, sulphur 0.021 weight %, copper 0.018 weight %, nickel 0.020 weight %, chromium 0.019 weight %.Molten iron temperature during oxygen blast gas is 1450-1695 ℃ (be 1450 ℃, oxygen blast is 1695 ℃ after finishing, and is a process that raises gradually) when oxygen blast begins, and the oxygen blown time is 13 minutes, and the oxygen blast total amount is 6283m 3, from the beginning oxygen blast to blowing oxygen quantity be to be blown into 90% of amount of oxygen, the flow of oxygen be 30000 SCMs/hour; Blowing oxygen quantity is after 90%, the flow of oxygen be 20000 SCMs/hour.
In the process of ladle, in ladle, add 48 kilograms of aluminium blocks at converter tapping, molten steel is carried out deoxidation.After the molten steel tapping was accomplished, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel was 0.09 weight %.Then desire control oxygen level is set at 0.036 weight %, uses 650 meters of the aluminum steels (about 130 kilograms) of feeding wire machine feeding Φ 10mm.
Then, ladle is delivered to furnaceman LF position and heat deoxidation.Use the LF device that the molten steel in the ladle is heated to 1625 ℃, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel is 0.05 weight %.Desire control oxygen level is set at 0.035 weight %, uses 140 meters of the aluminum steels (about 28 kilograms) of feeding wire machine feeding Φ 10mm, the oxygen level of using apparatus for determination of oxygen to record in the molten steel is 0.038 weight %.
Then, ladle is delivered to the RH station and carry out vacuum outgas.At first under 120mbar vacuum tightness, outgasing 3 minutes, under the vacuum tightness of 10mbar, outgasing 20 minutes then.After the degassing is accomplished, in ladle, add 65 kilograms of aluminum shots, the weight of measuring molten steel then is 120 tons, in the molten steel carbon content be 0.022 weight %, the acid-soluble aluminum content in the molten steel is 0.04 weight %, oxygen level is 0.0031 weight %.
Then the molten steel that obtains continuous casting on 4 machines, 4 stream billet casters is become the continuously cast bloom of 360 * 450 * 6000mm, the tundish temperature of continuous caster is controlled to be 1550 ℃, in the casting cycle; The carbon content of getting steel appearance mensuration molten steel at the continuous casting tundish is 0.02 weight %, and acid-soluble aluminum content is 0.035 weight %, and full aluminium content is 0.046 weight %; Silicone content is 0.005 weight %, and manganese content is 0.031 weight %, and phosphorus content is 0.006 weight %; Sulphur content is 0.013 weight %, and copper content is 0.017 weight %, and nickel content is that 0.018 weight %, chromium content are 0.016 weight %; Iron level has reached the requirement of technically pure iron more than 99.8 weight %.
Embodiment 3
Present embodiment is used to explain the method for manufacture pure iron provided by the invention.
In 120 tons of converters, add 130 tons of molten iron, be blown into oxygen and carry out converter and just refine, oxygen blast obtains the molten steel that carbon content is 0.05 weight % after finishing, and under 1700 ℃, this molten steel is tapped in the ladle.Wherein, mainly consisting of of molten iron: iron 95.19 weight %, carbon 4.45 weight %, silicon 0.065 weight %, manganese 0.090 weight %, phosphorus 0.032 weight %, sulphur 0.015 weight %, copper 0.021 weight %, Ni 0.017 weight %, Cr 0.021 weight %.Molten iron temperature during oxygen blast gas is 1400-1700 ℃ (be 1400 ℃, oxygen blast is 1700 ℃ after finishing, and is a process that raises gradually) when oxygen blast begins, and the oxygen blown time is 15 minutes, and the oxygen blast total amount is 7250m 3, from the beginning oxygen blast to blowing oxygen quantity be to be blown into 90% of amount of oxygen, the flow of oxygen be 30000 SCMs/hour; Blowing oxygen quantity is after 90%, the flow of oxygen be 20000 SCMs/hour.
In the process of ladle, in ladle, add 45.5 kilograms of aluminium blocks at converter tapping, molten steel is carried out deoxidation.After the molten steel tapping was accomplished, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel was 0.075 weight %.Then desire control oxygen level is set at 0.032 weight %, uses 400 meters of the aluminum steels (about 80 kilograms) of feeding wire machine feeding Φ 10mm.
Then, ladle is delivered to furnaceman LF position and heat deoxidation.Use the LF device that the molten steel in the ladle is heated to 1625 ℃, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel is 0.38 weight %.
Then, ladle is delivered to the RH station and carry out vacuum outgas.At first under 100mbar vacuum tightness, outgasing 3 minutes, under the vacuum tightness of 3mbar, outgasing 10 minutes then.After the degassing is accomplished, in ladle, add 60 kilograms of aluminum shots, the weight of measuring molten steel then is 129 tons, in the molten steel carbon content be 0.02 weight %, the acid-soluble aluminum content in the molten steel is 0.022 weight %, oxygen level is 0.0040 weight %.
Then the molten steel that obtains continuous casting on 4 machines, 4 stream billet casters is become the continuously cast bloom of 360 * 450 * 6000mm, the tundish temperature of continuous caster is controlled to be 1575 ℃, in the casting cycle; The carbon content of getting steel appearance mensuration molten steel at the continuous casting tundish is 0.02 weight %, and acid-soluble aluminum content is 0.025 weight %, and full aluminium content is 0.033 weight %; Silicone content is 0.005 weight %, and manganese content is 0.025 weight %, and phosphorus content is 0.006 weight %; Sulphur content is 0.012 weight %, and copper content is 0.02 weight %, and nickel content is that 0.02 weight %, chromium content are 0.018 weight %; Iron level has reached the requirement of technically pure iron more than 99.8 weight %.
Embodiment 4
Present embodiment is used to explain the method for manufacture pure iron provided by the invention.
In 120 tons of converters, add 125 tons of molten iron, be blown into oxygen and carry out converter and just refine, oxygen blast obtains the molten steel that carbon content is 0.04 weight % after finishing, and under 1680 ℃, this molten steel is tapped in the ladle.Wherein, mainly consisting of of molten iron: iron 95.19 weight %, carbon 4.45 weight %, silicon 0.065 weight %, manganese 0.090 weight %, phosphorus 0.032 weight %, sulphur 0.015 weight %, copper 0.021 weight %, Ni 0.017 weight %, Cr 0.021 weight %.Molten iron temperature during oxygen blast gas is 1400-1700 ℃ (be 1400 ℃, oxygen blast is 1700 ℃ after finishing, and is a process that raises gradually) when oxygen blast begins, and the oxygen blown time is 15 minutes, and the oxygen blast total amount is 7250m 3, from the beginning oxygen blast to blowing oxygen quantity be to be blown into 90% of amount of oxygen, the flow of oxygen be 30000 SCMs/hour; Blowing oxygen quantity is after 90%, the flow of oxygen be 20000 SCMs/hour.
In the process of ladle, in ladle, add 110 kilograms of ferro-aluminums (wherein, the content of aluminium is 40 weight %, and the content of iron is 60 weight %) at converter tapping, molten steel is carried out deoxidation.After the molten steel tapping was accomplished, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel was 0.075 weight %.Desire control oxygen level is set at 0.04 weight %, uses 330 meters of the aluminum steels (about 66 kilograms) of feeding wire machine feeding Φ 10mm.
Then, ladle is delivered to furnaceman LF position and heat deoxidation.Use the LF device that the molten steel in the ladle is heated to 1625 ℃, the oxygen level of using apparatus for determination of oxygen to measure in the molten steel is 0.55 weight %.Desire control oxygen level is set at 0.035 weight %, uses 190 meters of the aluminum steels (about 38 kilograms) of feeding wire machine feeding Φ 10mm, the oxygen level of using apparatus for determination of oxygen to record in the molten steel is 0.038 weight %.
Then, ladle is delivered to the RH station and carry out vacuum outgas.At first under 100mbar vacuum tightness, outgasing 3 minutes, under the vacuum tightness of 3mbar, outgasing 10 minutes then.After the degassing is accomplished, in ladle, add 60 kilograms of aluminum shots, the weight of measuring molten steel then is 124 tons, in the molten steel carbon content be 0.02 weight %, the acid-soluble aluminum content in the molten steel is 0.038 weight %, oxygen level is 0.0029 weight %.
Then the molten steel that obtains continuous casting on 4 machines, 4 stream billet casters is become the continuously cast bloom of 360 * 450 * 6000mm, the tundish temperature of continuous caster is controlled to be 1575 ℃, in the casting cycle; The carbon content of getting steel appearance mensuration molten steel at the continuous casting tundish is 0.02 weight %, and acid-soluble aluminum content is 0.04 weight %, and full aluminium content is 0.048 weight %; Silicone content is 0.006 weight %, and manganese content is 0.021 weight %, and phosphorus content is 0.006 weight %; Sulphur content is 0.012 weight %, and copper content is 0.018 weight %, and nickel content is that 0.02 weight %, chromium content are 0.018 weight %; Iron level has reached the requirement of technically pure iron more than 99.8 weight %.

Claims (10)

1. the method for a manufacture pure iron is characterized in that, this method may further comprise the steps:
Converter is just refined, and refining makes molten iron be converted into molten steel to use converter to carry out just;
Ladle deoxidation is tapped the molten steel in the converter in the ladle, and in ladle, is added aluminium, makes oxygen level in the molten steel for greater than 0.04 weight % to 0.06 weight %;
The heating deoxidation is heated to 1620-1660 ℃ with the molten steel behind the ladle deoxidation, in ladle, adds aluminium, makes the oxygen level in the molten steel reach 0.03-0.04 weight %;
Vacuum outgas outgases to the molten steel after the heating deoxidation under vacuum condition, and the carbon content to molten steel reaches below the 0.03 weight %, adds aluminium again and makes the acid-soluble aluminum content in the molten steel reach 0.02-0.05 weight %.
2. method according to claim 1; Wherein, The said converter just method of refining comprises molten iron is joined in the converter that oxygen blast gas in converter, the molten iron temperature during oxygen blast gas are 1400-1700 ℃; The time that oxygen is blown into is 8-25 minute, and the amount of being blown into of oxygen makes the carbon content in the molten iron be not more than 0.05 weight %.
3. method according to claim 1 and 2; Wherein, mainly consisting of of said molten iron: the phosphorus of the silicon of the carbon of 3.5-4.5 weight %, 0.15-0.3 weight %, the manganese of 0.2-0.5 weight %, 0.06-0.08 weight %, the sulphur of 0.005-0.01 weight % and the iron of 93-96.5 weight %.
4. method according to claim 1 wherein, in the step of said ladle deoxidation, with respect to molten iron per ton, adds the aluminium of 0.3-0.4 kilogram in ladle.
5. according to claim 1 or 4 described methods, wherein, in the step of said ladle deoxidation; With respect to molten iron per ton, in ladle, add the aluminium of 0.3-0.4 kilogram, measure the oxygen level in the molten steel then; If the oxygen level in the molten steel that records is greater than 0.06 weight %; Then in molten steel, add aluminium again, with respect to molten iron per ton, the amount of the aluminium that adds again is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1 gram is to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2.5 grams; Wherein, said desire control oxygen level is 0.03-0.05 weight %.
6. method according to claim 5; Wherein, With respect to molten iron per ton; The amount of the aluminium that adds again is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1.5 grams are to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2 grams, and wherein, said desire control oxygen level is 0.03-0.04 weight %.
7. method according to claim 1, wherein, during said tapping, the temperature of molten steel is 1670-1700 ℃.
8. method according to claim 1; Wherein, In said heating deoxygenation step, with respect to molten iron per ton, the amount of the aluminium of adding is: (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 1 gram is to (oxygen level that records-desire control oxygen level) ÷ 0.0001 weight % * 2.5 grams; Wherein, said desire control oxygen level is 0.03-0.04 weight %.
9. method according to claim 8; Wherein, this method is measured the oxygen level in the molten steel after also being included in and adding aluminium, if the oxygen level in the molten steel that records is greater than 0.04 weight %; Then repeat the step of this adding aluminium, reach 0.03-0.04 weight % up to the oxygen level that records.
10. method according to claim 1, wherein, in said vacuum outgas step, vacuum tightness is the 1-500 millibar, the time of the degassing is 2-60 minute.
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