CN101305105B - Method of hot metal dephosphorization treatment - Google Patents
Method of hot metal dephosphorization treatment Download PDFInfo
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- CN101305105B CN101305105B CN2006800418425A CN200680041842A CN101305105B CN 101305105 B CN101305105 B CN 101305105B CN 2006800418425 A CN2006800418425 A CN 2006800418425A CN 200680041842 A CN200680041842 A CN 200680041842A CN 101305105 B CN101305105 B CN 101305105B
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- oxygen source
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/02—Dephosphorising or desulfurising
- C21C1/025—Agents used for dephosphorising or desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
- C21C7/0645—Agents used for dephosphorising or desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
A method of hot metal dephosphorization treatment, comprising adding a dephosphorization refining agent composed mainly of CaO and reducing the added dephosphorization refining agent composed mainly of CaO to slags to thereby accomplish dephosphorization of the hot metal, wherein a gaseous oxygen source is fed from one supply system to a surface of hot metal bath and a solid oxygen source is fed from another supply system to a surface of hot metal bath in the vicinity of the site where the gaseous oxygen source is fed by the use of carrier gas. Thus, without the use of any medium solvent containing fluorine, there can be accomplished dephosphorization treatment with dephosphorization efficiency and iron yield equal to or higher than those of the prior art.
Description
Technical field
The present invention relates to the dephosphorization treatment method of molten iron, be specifically related to not use the fluorine source also can carry out the method for dephosphorization treatment effectively to molten iron with the high ferro yield rate as solubility promoter.
Background technology
In using blast-melted process for making, carry out before the decarburization blowing with converter, utilize oxygen, solid ferric oxide that the Si that contains in the molten iron and P most carried out the so-called hot metal pretreatment such as desulfurizing iron processing that dephosphorization of molten iron that oxidation removes is handled or remove the S that contains in the molten iron by sweetening agent under reducing atmosphere usually.
In recent years, before comparing, the quality requirements that steel products require increases and the strictness that becomes, more than the minimizing requirement level up to now of phosphorus concentration.In order to tackle this quality requirements, the iron water amount that need particularly will carry out dephosphorization treatment in hot metal pretreatment is increased in the past more than the level, or stably reduces the phosphorus concentration after the dephosphorization treatment.
On the other hand, in order to tackle the environmental influence of recent Global warming representative, must reduce the slag output in the steel making working procedure.In order in the dephosphorization treatment of molten iron, to reduce the output of slag, must be reduced to input amount for the dephosphorization refining agent of the slag (" dephosphorization refining slag ") that fusion plays a role with refining agent as dephosphorization.In dephosphorization of molten iron is handled, the main body of dephosphorization refining agent is a lime, reduce the slag output when tackling above-mentioned quality requirements, the technology that needs to reduce the usage quantity of lime and keep necessary dephosphorization amount is promptly carried out the technology of dephosphorization treatment effectively with the usage quantity of less lime.
In dephosphorization treatment, owing to there is not the lime of scorification (fluxing) dephosphorisation reaction not to be contributed, thereby in order to reduce the usage quantity of lime, the scorification of the lime that added of promotion importantly.In the past, with solubility promoter (fluxing agent) is known fluorite (with the ore of Calcium Fluoride (Fluorspan) as principal constituent) arranged, in dephosphorization treatment, also used fluorite as promoting with the good scorification of the fluxing power of the slag headed by the lime.But in recent years, along with the reinforcement of environmental restraint, fluorine-containing solubility promoter is used in restriction, and therefore, research is not used fluorite and promoted method based on the dephosphorisation reaction of lime, has made a lot of motions.
As one of them method, the technology that the replacement fluorite utilizes other solubility promoters (scorification promotor) has been proposed.For example, following method has been proposed in TOHKEMY 2002-309312 communique: in the Decarburising and refining or dephosphorization treatment of molten iron, replace fluorite to use salic solubility promoter.
But the aluminum oxide that replaces fluorite to propose in TOHKEMY 2002-309312 communique though promote the scorification of slag, has the effect that improves slag viscosity.Therefore, the usage quantity of aluminum oxide is more for a long time after the dephosphorization treatment, when discharging slag from reaction vessel, exists slag attached in the stove and residual situation.Thus, the phosphorus that produces when carrying out dephosphorization treatment in next one charging (filling molten iron) in the residual molten iron returns molten iron, so-called " rephosphorization (re-phosphorization) ", exists the dysgenic problem that produces is handled in the disengaging of next one charging.And, also exist the slag viscosity height to cause that the more iron of seizure drips (metal droplet or iron droplet) in slag, this iron drops in and is brought to the problem that stove reduces the iron yield rate outward when discharging slag.
On the other hand, promote the method for the scorification of lime as not relying on scorification promotor, will be in TOHKEMY 2000-144226 communique by the treatment agent of unslaked lime, ferric oxide and/or oxygen CaO/O ratio that form, that become regulation, supply to the technology of the same area of molten iron simultaneously, promptly the contact part between oxygen and molten metal face (being known as " burning-point ") drops into the technology of unslaked lime.
On the other hand, in TOHKEMY 2003-328021 communique, introduced following content: oxygen is used gas as carrying, when being blown into limy refining agent, the contact part between oxygen and the molten metal face, promptly burning-point becomes high temperature and carries out the scorification of lime.In TOHKEMY 2003-328021 communique, and then disclose following content: what make dephosphorisation reaction in order to prevent burning-point from becoming high temperature carries out slack-offly, supplies with the refining agent contain the material that absorb heat to burning-point, the dephosphorization efficient in the raising burning-point portion.
But the decarburizing reaction based on oxygen in the burning-point is preponderated, and surpasses 2000 ℃ high temperature because of the heating of decarburizing reaction etc. becomes.Therefore, its burden that is cooled to suitable temperature is bigger, and requirement more effectively improves the method for dephosphorization efficient.
Summary of the invention
The present invention makes in view of the above problems, when its purpose is to provide molten iron is carried out dephosphorization treatment, do not use the fluorine-containing solubility promoter can be with the usage quantity of less lime yet, with identical in the past dephosphorization efficient and iron yield rate carry out dephosphorization treatment, more in the past than the dephosphorization treatment method of the molten iron that disclosed method was favourable.
Be used to solve the dephosphorization treatment method of molten iron of first invention of above-mentioned problem, dephosphorization refining agent based on CaO is added in the molten iron, what make interpolation forms slag based on the dephosphorization refining agent scorification of CaO, implement dephosphorization treatment with respect to molten iron, it is characterized in that, bathe face supply gas oxygen source from a plenum system to molten iron, from another plenum system, near the molten iron bath face utilization the position of supply gas oxygen source is carried with gas and is supplied with the solid oxygen source.
The dephosphorization treatment method of the molten iron of second invention in first invention, is characterized in that the plenum system separately with above-mentioned gas oxygen source and solid oxygen source is configured in the identical oxygen lance.
The dephosphorization treatment method of molten iron of the 3rd invention in first or second invention, is characterized in that, will be based on the dephosphorization refining agent of CaO, and the plenum system by the above-mentioned gas oxygen source supplies to molten iron with the above-mentioned gas oxygen source and bathes face.
The dephosphorization treatment method of the molten iron of the 4th invention, in each invention in first to the 3rd, it is characterized in that, the conveying gas of above-mentioned solid oxygen source is any gas more than a kind or 2 kinds in air, reducing gas, carbonic acid gas, non-oxidizing gas, the rare gas, and oxygen concn is lower than above-mentioned gas oxygen source.
The dephosphorization treatment method of the molten iron of the 5th invention, in each invention in first to the 4th, it is characterized in that above-mentioned solid oxygen source is any more than a kind or 2 kinds in the agglomerate of granularity below 1mm, roll scale (mill scale), control of dust powder, iron sand, the iron ore.
The dephosphorization treatment method of the molten iron of the 6th invention, in converter, dephosphorization refining agent based on CaO is added in the molten iron with oxygen source, what make interpolation forms slag based on the dephosphorization refining agent scorification of CaO, implement dephosphorization treatment with respect to molten iron, it is characterized in that, use the top blast oxygen lance that has 2 feed paths at least, supply with dephosphorization refining agent based on CaO to the molten iron face of bathing with the gas oxygen source from one of them plenum system, from another plenum system, near the position identical with the position of supply gas oxygen source molten iron is bathed face, with air, reducing gas, carbonic acid gas, non-oxidizing gas, any gas more than a kind or 2 kinds in the rare gas is supplied with the solid oxygen source as conveying with gas.
The dephosphorization treatment method of molten iron of the 7th invention in each invention in first to the 6th, is characterized in that, forms a plurality of burning-points by the supply of gas oxygen source, supplies with the solid oxygen source to the position that is surrounded by described a plurality of burning-points.
Embodiment
Below, the present invention is specifically described.
The dephosphorization treatment of molten iron, with refining furnaces such as molten iron conveying container such as mixer type iron ladle car, molten iron pot or converters as reaction vessel.Undertaken by following method: will add in the molten iron as solid oxygen sources such as gas oxygen sources such as the dephosphorization refining agent of main body, oxygen and solid ferric oxide with CaO, by gas oxygen source and solid oxygen source the phosphorus in the molten iron is carried out oxidation, the phosphorous oxides that produces is packed into by in the dephosphorization refining usefulness slag that forms based on the dephosphorization refining agent of CaO etc., remove the phosphorus in the molten iron.Gas oxygen source and solid oxygen source are referred to as oxygen source.
When considering from the principle aspect, about dephosphorisation reaction, the solid oxygen source is more efficient than gas oxygen source.This is that low temperature is favourable more on thermodynamics because of dephosphorisation reaction.Cause decarburization and dephosphorization when in molten iron, dropping into oxygen, but the temperature that the decarburization heating causes under the situation that drops into the gas oxygen source rises and preponderates, with respect to this, under the situation that drops into the solid oxygen source,, thereby can suppress temperature and rise because the solid oxygen source is followed heat absorption when decomposing.That is,, can keep the temperature favourable to dephosphorisation reaction by using the solid oxygen source.In order to promote dephosphorisation reaction, need the temperature condition of degree that can the molten solids oxygen source.And the solid oxygen source forms FeO after having fusion, increase is contributed to dephosphorisation reaction, the dephosphorization refining function of the FeO composition in the slag, and the inhibition effect that rises with said temperature interacts and the promotion dephosphorisation reaction.
In the past, the solid oxygen source fell to dropping into dephosphorization treatment from the hopper of the top that is arranged at reaction vessel usually.In this case, because the solid oxygen source can not attracted to exhaust system, thereby use the granular or block of number mm～tens of mm.Even granular or blocky solid oxygen source is put into also not fusion immediately in the reaction vessel, remain to the time point that finishes up to dephosphorization treatment sometimes.And, though the FeO in the slag rises because of the fusion of solid oxygen source, be reduced, thereby under the identical situation of the reduction rate of the fusion speed of solid oxygen source and FeO, the FeO concentration in the slag can not rise because FeO in the slag and the carbon in the molten iron react.That is, if the fusion speed of solid oxygen source is not more than the reduction rate of the FeO in the slag, not rising in the oxygen position in the slag, can not expect the raising of dephosphorization speed.
In the present invention, bathe face supply gas oxygen source from a plenum system to molten iron, from another plenum system, near the molten iron bath face utilization the position of supply gas oxygen source is carried with gas and is supplied with the solid oxygen source.
In molten iron bath face, the position that the gas oxygen source contacts with molten iron bath face is a burning-point, because of the gas oxygen source forms superfluous hyperoxia potential field (excessively high oxygen potential field), but becomes high temperature because of the reaction of the carbon in gas oxygen source and the molten iron.Thereby, even supply with the solid oxygen source, can not obtain significant effect from oxygen position and refrigerative viewpoint to burning-point.
On the other hand, near the circumference the burning-point, though because temperature can be kept higher temperature than burning-point is low, thereby to the solid oxygen source fusion rapidly of its supply.And, can not form hyperoxia potential field as the surplus of burning-point, the solid oxygen source can be contributed to reaction effectively.Thus, rise in the oxygen position of slag, and promptly rapid formation is suitable for the slag of dephosphorisation reaction most, even less slag amount just can carry out dephosphorization treatment as long as be under the high temperature.In addition, alleged among the present invention " near the molten iron the position of supply gas oxygen source is bathed face ", be meant face that originally institute's gas supplied oxygen source contacts with molten iron near.For example, under the situation of top blast oxygen lance supply gas oxygen source, be the gas oxygen source that sprays from the top blast oxygen lance with molten iron bath face position contacting near, utilizing injection oxygen lance or air port in molten iron, injects under the situation of (being blown into) gas oxygen source, be the gas oxygen source face (also being defined as " burning-point " in this case) that enters molten iron in the outlet of injecting oxygen lance or air port near.Wherein, in common dephosphorization treatment, even also keep higher temperature because the bath surface temperature leaves the bath face of the molten iron of supply gas oxygen source, thereby the supply optimum seeking site of solid oxygen source is the part higher than the medial temperature of molten iron integral body.
In addition preferably, from must be inconsistent between the center of the supply position on the bath face of two systems, prevent that the center of the supply position of solid oxygen source from entering the zone of burning-point.But can overlappingly can not be a problem in supply area itself yet.And, owing to go into different gas to bathing top blast from two systems, even thereby quite close between the center of the supply position on the above-mentioned bath face, if in fact also inconsistent, just can guarantee regional difference, can not be a problem.
Gas oxygen source as using in the present invention can use the mixed gas of oxygen (comprising industrial pure oxygen), air, oxygen-rich air, oxygen and rare gas element etc.Under the situation of common dephosphorization treatment,, thereby use oxygen because to compare dephosphorisation reaction speed fast with the situation of using other gases.Under the situation of mixed gas,, preferably make oxygen concn be higher than air in order to ensure dephosphorisation reaction speed.
As optimal way of the present invention, use air, non-oxidizing gas, rare gas, reducing gas, conduct near any gas more than a kind or 2 kinds in the carbonic acid gas of the weak oxide gas of non-oxidizing gas with gas as the conveying of solid oxygen source.Here, reducing gas is meant hydrocarbon class gas and CO gases such as propane flammable gas, and non-oxidizing gas is meant that nitrogen etc. does not have the gas of oxidation capacity, and rare gas is meant rare gas elementes such as Ar gas, He gas.By using above-mentioned gas, can suppress near the temperature of burning-point and rise, can create the dephosphorization advantageous conditions on the principle.
In the present invention, even the conveying of solid oxygen source contains the gas of oxygen to a certain degree with gas air etc., also can obtain effect.But from the above point of view, carry concentration with oxygen contained in the gas, preferably low than gas oxygen source.For example, be under the situation of air at the gas oxygen source, preferably use non-oxidizing gas, rare gas, reducing gas, carbonic acid gas etc. as the conveying of solid oxygen source with gas.And, be under the situation of pure oxygen or oxygen-rich air etc. at the gas oxygen source, can use above-mentioned whole conveying gases.
In addition, the solid oxygen source that has contain the trace metallic iron, in pure oxygen gas flow the burning and might bring damage to equipment.When using gas delivery solid oxygen source, also effective from the industrial point that prevents accident with the oxygen concn conveying lower than air.
In the present invention, the dephosphorization refining agent based on CaO also can separate input with the gas oxygen source from hopper etc.But in mode of the present invention and then preferred, supply with the dephosphorization refining agent of CaO to molten iron bath face as main body with the gas oxygen source.Thus, also under high-temperature atmosphere, be heated as the dephosphorization refining agent of main body itself with CaO, thereby can make scorification rapider.That is, can further promote dephosphorisation reaction.
Use in the present invention with the dephosphorization refining agent of CaO as main body, as long as contain CaO and can carry out the desirable dephosphorization treatment of the present invention, do not limit the content of CaO especially.Be generally the material that forms by the CaO monomer or contain more than the CaO50 quality %, contain the material of other compositions as required.
Generally can enumerate scorification promotor as other compositions.That is,, do not forbid adding scorification promotor and improve scorification efficient though the application may reduce or omit the technology of scorification promotor.As scorification promotor, can enumerate especially to contain and have the fusing point that reduces CaO and titanium oxide, the aluminum oxide (Al that promotes the effect of scorification
2O
3) material, preferably with described material as the part of solubility promoter.Wherein, from the viewpoint of slag viscosity, preferably add titanium oxide.And, also can be with fluorine-containing materials such as fluorites as scorification promotor.When slag is carried out off gas treatment etc.,, preferably do not use fluorine-containing material as solubility promoter from suppressing to protect the viewpoint of environment from the elution amount of the fluorine of slag.The material of sneaking into inevitably as impurity component about fluorine then can use.Certainly, contain in use under the situation of the material of titanium oxide, salic material, from this viewpoint, because not fluorine-containing, thus preferred.
As with the concrete example of CaO as the dephosphorization refining agent of main body, because unslaked lime, Wingdale cheapness and dephosphorizing capacity are good, thereby preferred the use.And, the also slag (being also referred to as " decarbonized slag (BOF slag or decarbulization slag) ") that can produce when in the converter of next operation the molten iron after light dolomite, the dephosphorization treatment being carried out Decarburising and refining is as with the dephosphorization refining agent of CaO as main body.Decarbonized slag since with CaO as principal constituent, and phosphorus content is less, thus can be fully as with the dephosphorization refining agent of CaO as main body.
And,, can use the agglomerate, roll scale, control of dust powder (powder), iron sand, iron ore of iron ore etc. as the solid oxygen source that uses in the present invention.The control of dust powder is meant and is included in the powder that divides from the iron content of waste gas recovery in blast furnace, converter, the sintering circuit.From the viewpoint of the fusionization that promotes the solid oxygen source, the powder body of solid oxygen source preferable particle size below 1mm.When particle diameter surpasses 1mm, be difficult to rapid fusion, the FeO composition of slag is difficult to rise.Here, particle diameter is meant by mesh size to be the screening washer of 1mm below 1mm, as long as can be the screening washer of 1mm by mesh size, also can be the fusiform that major diameter surpasses 1mm.In addition, from the viewpoint of operation, particle diameter is preferably more than 1 μ m.
In above-mentioned solid oxygen source, the iron ore of iron sand and micro mist is a micro mist below the 1mm as producing form, owing to do not need to carry out pulverization process, thereby be particularly suitable for.Wherein,, but also contain titanium oxide about 7～10%, thereby also have, be particularly suitable for as function based on the scorification promotor of the refining agent of CaO because iron sand not only plays a role as the solid oxygen source.
The slag of titanium oxide when dephosphorization treatment plays a role as acidic oxide in forming, and makes as dephosphorization good with the effect of the CaO scorification of the main body of dephosphorization refining agent.That is, contain the iron sand of titanium oxide, promote to promote dephosphorisation reaction as the scorification of the dephosphorization refining agent of main body with CaO by interpolation.And titanium oxide has the effect that is reduced by the slag viscosity that forms as the dephosphorization refining agent of main body with CaO that makes, and thus, after dephosphorization treatment, plays the effect that slag is discharged from reaction vessel easily.Therefore, the slag residual quantity of discharging in the reaction vessel behind the slag is reduced to negligible degree, in the dephosphorization treatment of next one charging, can not hinder dephosphorisation reaction because of rephosphorization etc., can carry out dephosphorization treatment effectively
The amount of the titanium oxide in the slag is scaled TiO
2Shi Youxuan is below 10 quality %.Because when surpassing 10 quality %, reduce as the ratio of the CaO of principal constituent, thereby offset the effect of improving of dephosphorizing capacity, the effect of interpolation is reduced.On the other hand, in order to obtain above-mentioned effects such as slag viscosity reduction reliably, the amount of titanium oxide is scaled TiO
2Shi Youxuan is more than 1 quality %.Be scaled TiO here,
2Be meant that titanium oxide has TiO, TiO
2, Ti
2O
3, Ti
3O
5Form, these Ti amount is scaled TiO
2And represent.
The reaction vessel that uses in dephosphorization treatment has no particular limits, and can use the molten iron pot, casting ladle type container, mixer type iron ladle car, converter etc. such as the pot of packing into.In dephosphorization treatment of the present invention, in order to advance dephosphorisation reaction, as oxygen source while supply gas oxygen source and solid oxygen source.Wherein the gas oxygen source can be by based on the top blast of top blast oxygen lance, supply with based on any means such as the injection in molten iron in injection oxygen lance or air port etc. or bottom blowings.The solid oxygen source need supply near the molten iron in position of supply gas oxygen source and bathe face.For example, be blown into from upside under the situation of gas oxygen source, near the supply solid oxygen source of the face that also contacts with molten iron bath face from last direction gas oxygen source preferably also can utilize near the supply solid oxygen source of carrying the face that contacts with molten iron bath face to the gas oxygen source with gases from injection oxygen lance or bottom blowing air port etc.Under the situation of gas oxygen source by injection oxygen lance or air port injection, by the system to identical injection oxygen lance or air port supply solid oxygen source is set, or independently injection oxygen lance or the air port of supplying with the solid oxygen source be set, enter in the outlet in injection oxygen lance or air port to the gas oxygen source molten iron face near supply solid oxygen source.
And, in dephosphorization treatment of the present invention, preferably also to supplying with dephosphorization refining agent based on CaO with the molten iron bath face of the position same area of supply gas oxygen source.For like this supply gas oxygen source and solid oxygen source and based on the dephosphorization refining agent of CaO, for example can be by oxygen lance (top blast oxygen lance, injection oxygen lance etc.) or air port at these materials of supply, 2 plenum systems are set at least, supply with dephosphorization refining agent from one of them plenum system with the gas oxygen source based on CaO, and supply with solid oxygen source with above-mentioned conveying with gas from another plenum system, reach above-mentioned adding conditional.Feed unit can be arbitrary unit such as top blast oxygen lance, injection oxygen lance, air port, because top blast oxygen lance thermal load is less and be imbued with wearing quality, and processing ease, thereby preferably supply with from the top blast oxygen lance.
Supply with the gas oxygen source, based on the size of the dephosphorization refining agent of CaO, from the viewpoint that promotes scorification preferably below 1mm.
The bath face of supply gas oxygen source, promptly the decarburizing reaction based on oxygen is preponderated in the burning-point, because of the heating of decarburizing reaction etc., for example becomes in the dephosphorization of converter and surpasses 2000 ℃ high temperature.On the other hand, dephosphorisation reaction considers that from the thermodynamics aspect low temperature promotes reaction.What therefore, in fact cause dephosphorisation reaction is roughly at the periphery below 1800 ℃ apart from the isolating a little temperature of burning-point.
The top blast oxygen lance, at least have 2 plenum systems, by from one of them system's supply gas oxygen source, from another system with carrying with near the supply solid oxygen source of gas to burning-point, the solid oxygen source can supply near burning-point, in fact promote the part of dephosphorisation reaction.The solid oxygen source, owing to supply with gas by the oxygen concn conveying lower than oxygen, thereby the temperature of this part can excessively not rise, can be by the good reactivity of solid oxygen source, and then promote dephosphorization.For example, the dephosphorizing capacity in 1800 ℃ is compared roughly multiplication during budgetary estimate with the dephosphorizing capacity in 2000 ℃ in thermodynamics.
As aforesaid structure with 2 plenum systems, can adopt following method: for example the top blast oxygen lance is made as at least double pipe structure and with the stream of a side as oxygen, the opposing party is used the stream of gas as solid oxygen source and conveying, from being configured in the oxygen lance central shaft is nozzle bore supply gas oxygen source on the concentric(al) circles at center, on the other hand, supply with solid oxygen source and conveying gas from the nozzle bore that is configured on the oxygen lance central shaft.In this method, supply by the gas oxygen source forms a plurality of burning-points, on the position that is surrounded by above-mentioned a plurality of burning-points, form the state of supplying with the solid oxygen source, thereby stably kept the condition of high temperature lower, thereby be particularly suitable for than burning-point by the solid oxygen source supply unit that burning-point surrounds.And, also can on the concentric(al) circles that with the oxygen lance central shaft is the center, dispose a plurality of nozzle bores, from replacing the hole supply gas oxygen source and the solid oxygen source of (different mutually).
Near the molten iron that all solids oxygen source that needn't supply with supplies to the position of supply gas oxygen source is bathed face, and near the molten iron that can only a part of solid oxygen source be supplied to the position of supply gas oxygen source is bathed face.But, supply to solid oxygen source that near the position of supply gas oxygen source molten iron bathes face more after a little while, because the rising of the FeO composition in the above-mentioned slag is less, thereby in order to prevent this situation, according to specification of equipment, the sufficient amount of the rising of FeO composition in the slag is made as lower limit gets final product.And,, be suppressed at the amount that hot-fluid can not become excessive according to specification of equipment and get final product as the upper limit.For example, the container about with 100～350 tons carries out under the situation of dephosphorization treatment, preferably, and with respect to the gas oxygen source 1Nm of the bath face of supplying to
3(the pure oxygen tolerance under the standard state) adds the solid oxygen source of supplying with gas by carrying in the scope more than 0.1kg, below the 2kg.Can not obtain the effect expected among the present invention during not enough 0.1kg fully, on the other hand, the hot flowage that supplies to when surpassing 2kg in the supply range of solid oxygen source is big, and the scorification of slag becomes insufficient and dephosphorizing capacity is reduced.And then preferred feed rate is more than 0.3kg.
The molten iron that supplies to the supply gas oxygen source is bathed near the solid oxygen source at the position in addition of face, supplies with by appropriate means such as top interpolation, injection interpolations to get final product.Equally, even under supplying with situation at the position beyond the bath face of the molten iron of supply gas oxygen source based at least a portion of the dephosphorization refining agent of CaO, also by the top add, appropriate means supply such as injection interpolations gets final product.
In addition, under the situation of using gas oxygen source, molten iron temperature rises because of oxidation reaction heat, use under the situation of solid oxygen source, because sensible heat, the latent heat and decomposition heat greater than oxidation reaction heat of solid oxygen source itself, thereby molten iron temperature reduces.Therefore, the usage rate of gas oxygen source and solid oxygen source is set according to the temperature before and after the processing of molten iron when keeping above-mentioned scope.And, in order to carry out dephosphorisation reaction effectively, preferably stir molten iron, stir as this, the gas stirring of generally utilize the injection oxygen lance, imbedding the nozzle etc. of furnace bottom gets final product.
As dephosphorization refining slag, because the preferred 10 quality % of FeO concentration in the slag are above, the scope below the 50 quality %, thereby preferably adjust the feed rate of solid oxygen source, so that the FeO concentration in the slag can be kept this scope.And then preferred range is below 30 quality %.
By carrying out the dephosphorization treatment of molten iron like this,, also can keep with identical in the past dephosphorization speed and carry out dephosphorization treatment even fluorine-containing material is not used as solubility promoter.Its result, the countermeasure of not taking fluorine to leak in the environment also can be utilized slag again, can prevent carrying capacity of environment.And, also can keep and identical in the past dephosphorization amount even improve the dephosphorization treatment temperature, in this case, the iron yield rate in the dephosphorization treatment can be kept a high position, can bring industrial useful effect.
Embodiment
(embodiment 1)
After with blast furnace casting bed (blast furnace casthouse) molten iron from blast furnace casting being carried out desiliconization and handles, be transported to the converter of 300 tons of capacity, implement to amount to 4 times dephosphorization treatment (example 1 to 4 of the present invention) in this converter.The phosphorus concentration unification of the molten iron before the dephosphorization treatment is 0.12 quality %, below the phosphorus concentration 0.020 quality % with the molten iron after the dephosphorization treatment, the iron yield rate more than 98% as target.Iron yield rate (η) is represented (η=100W/ (Wo+Ws)) with respect to the total mass (Wo+Ws) of the quality (Ws) of the quality (Wo) of the molten iron in the converter of packing into and scrap metal with per-cent with the quality (W) of the molten iron that taps a blast furnace after the dephosphorization treatment and is obtained.
Dephosphorization treatment uses the top blast oxygen lance to carry out, described top blast oxygen lance, beyond the water supply and sewerage system of water coolant, have isolating 2 plenum systems, supply with oxygen and calcium lime powder (median size is below 1mm) from a plenum system, nitrogen is supplied with the solid oxygen source of powder as conveying with gas from another plenum system.Being constructed as follows of top blast oxygen lance: the plenum system of oxygen and solid oxygen source is made as the double pipe structure, with the stream of a side as oxygen, the opposing party is used the stream of gas as solid oxygen source and conveying, from being configured in the oxygen lance central shaft is a plurality of nozzle bore supply gas oxygen sources on the concentric(al) circles at center, on the other hand, supply with solid oxygen source and conveying gas from the single nozzle bore that is configured on the oxygen lance central shaft.
Supply with the solid oxygen source, enter the zone of burning-point with the center that prevents to supply with the position.
Do not add fluorine-containing materials such as fluorite and handle.From the air port of converter furnace bottom, as stirring gas and with the per 1 ton of molten iron 0.03～0.30Nm of correspondence
3The flow of/min is blown into nitrogen.
As the solid oxygen source, use any a kind in the agglomerate (mean particle size is 100 μ m) of powdered iron ore (mean particle size is 50 μ m), iron sand (mean particle size is 100 μ m), roll scale (mean particle size is 500 μ m), iron ore, be blown into molten iron and bathe face.The sour condition of sending of oxygen is corresponding per 1 ton of molten iron 0.6～2.5Nm
3/ min.The oxygen fundamental unit, removing the required oxygen of desiliconization is 12Nm
3/ t.
And, as a comparative example, also implemented to drop into the dephosphorization treatment of granulous iron ore (mean particle size is approximately 20mm) from stove upside hopper from the top.Other dephosphorization treatment conditions of comparative example are carried out according to example of the present invention.Hot metal composition and operating condition before and after the dephosphorization treatment in table 1 expression the present invention's example and comparative example.Fundamental unit and solid oxygen source usage quantity are shown with the scale of the every 1t molten iron of correspondence.
In addition, the amount of the titanium oxide in the slag with iron sand during as the solid oxygen source is scaled TiO
2Shi Chengwei 4 quality %.
Table 1
*) by carrying solid oxygen source of supplying with gas and the O that supplies with from the top blast oxygen lance
2The ratio of gas
As shown in table 1, to supply with in whole example of the present invention of solid oxygen source being blown into from the face of the oxygen of top blast oxygen lance, phosphorus concentration is below 0.020 quality % in the molten iron after the dephosphorization treatment, and the iron yield rate becomes more than 98%.With respect to this, in comparative example, phosphorus concentration is higher than 0.020 quality % in the molten iron after the dephosphorization treatment, and when reducing this concentration, the iron yield rate reduces and is lower than 98%, can confirm to satisfy both simultaneously.
(embodiment 2)
After with the blast furnace casting bed molten iron from blast furnace casting being carried out desiliconization, be transported to the converter of 300t capacity, implement to amount to 15 times dephosphorization treatment (example 11 to 25 of the present invention) in this converter.Dephosphorization treatment and embodiment 1 implement in the same manner, below the phosphorus concentration 0.020 quality % with the molten iron after the dephosphorization treatment, the iron yield rate more than 98% as target.
As ferric oxide, using mean particle size is the iron sand of 100 μ m.Ferric oxide adopts simultaneously based on carrying dropping into from the supply of top blast oxygen lance with from the top of stove elevating hopper with gas.
As the dephosphorization refining agent, use calcium lime powder of supplying with from the plenum system of gas oxygen source (median size is below 1mm) and the block lime (median size is approximately 10mm) that drops into from the stove elevating hopper from the top simultaneously, adjusted basicity (the CaO composition and the SiO in the slag of slag
2The weight ratio of composition).In addition,, do not supply with calcium lime powder, only drop into block lime up from the stove elevating hopper from the plenum system of gas oxygen source about example 18.And, about example 22, from the plenum system of gas oxygen source, except calcium lime powder is also supplied with limestone powder (median size is below 1mm).
And, as a comparative example 11～14, under the situation that does not drop into ferric oxide, do not carrying out dephosphorization treatment from the top blast oxygen lance yet.And, as a comparative example 15 to 17, under the situation of a part of supplying with ferric oxide from the plenum system of gas oxygen source, also carried out dephosphorization treatment.Other dephosphorization treatment conditions are relatively carried out according to example of the present invention.
Hot metal composition and operating condition before and after the dephosphorization treatment in table 2 expression the present invention's example and comparative example.
Table 2
*) by carrying solid oxygen source of supplying with gas and the O that supplies with from the top blast oxygen lance
2The ratio of gas
As shown in table 2, even drop into from the top under the situation of a part of oxygen source, in example of the present invention, phosphorus concentration is also below 0.020 quality % in the molten iron after the dephosphorization treatment, and the iron yield rate becomes more than 98%.With respect to this, in comparative example, can not realize phosphorus concentration in the molten iron after the dephosphorization treatment simultaneously: the following and iron yield rate of 0.020 quality %: more than 98%.
(embodiment 3)
After with the blast furnace casting bed molten iron from blast furnace casting being carried out desiliconization, be transported to the converter of 300t capacity, implement to amount to 2 times dephosphorization treatment (example 31 to 32 of the present invention) in this converter.As bottom blown gas, from the interior pipe in the air port of the double pipe of converter furnace bottom structure as stirring gas with the per 1 ton of about 0.8Nm of molten iron of correspondence
3The flow of/min is blown into oxygen.Be blown into beyond the propane flammable gas that is used for cooling air port from outer tube, implement dephosphorization treatment in the same manner with embodiment 1.As ferric oxide, using mean particle size is the roll scale of 500 μ m.Below the phosphorus concentration 0.020 quality % with the molten iron after the dephosphorization treatment, the iron yield rate more than 98% as target.
Hot metal composition and operating condition before and after the dephosphorization treatment in table 3 expression example of the present invention.
Table 3
*) by carrying solid oxygen source of supplying with gas and the O that supplies with from the top blast oxygen lance
2The ratio of gas
Industrial applicibility
According to the present invention, when carrying out the dephosphorization treatment of molten iron, the dephosphorization refining agent take CaO as main body is added in the molten iron, bathe face supply gas oxygen source from a feed system to molten iron, from another feed system, supply with the solid oxygen source near the molten iron bath face the position of supply gas oxygen source. Thus, the melting of solid oxygen source is changed rapidly, the dephosphorization refining is risen rapidly with the oxygen position of slag, improves the dephosphorizing capacity of this slag. By improving the dephosphorizing capacity of slag, even with the use amount more in the past than the lime that lacked, and make the dephosphorization refining with the basicity (CaO/SiO of slag in order to improve the iron yield rate2) reduction compared with the past or make dephosphorization treatment after molten iron temperature rising compared with the past, can not hinder dephosphorisation reaction yet, can effectively carry out dephosphorization treatment to molten iron. And, conveying gas as the solid oxygen source, owing to use the oxygen concentration gases lower than gas oxygen source such as air, reducibility gas, carbon dioxide, non-oxidizing gas, rare gas, thereby can not form as burning-point superfluous hyperoxia potential field, can suppress decarburizing reaction and and then effectively promote dephosphorisation reaction.
Claims (8)
1. the dephosphorization treatment method of a molten iron is added the dephosphorization refining agent based on CaO in the molten iron to, and what make interpolation forms slag based on the dephosphorization refining agent scorification of CaO, implements dephosphorization treatment with respect to molten iron, it is characterized in that,
Bathe face supply gas oxygen source from a plenum system to molten iron, carry with gas near the molten iron bath face utilization of another plenum system position of supply gas oxygen source and supply with the solid oxygen source.
2. the dephosphorization treatment method of molten iron as claimed in claim 1 is characterized in that, the plenum system separately with described gas oxygen source and solid oxygen source is configured in the identical oxygen lance.
3. the dephosphorization treatment method of molten iron as claimed in claim 1 is characterized in that, will be based on the dephosphorization refining agent of CaO, and the plenum system by described gas oxygen source supplies to molten iron with described gas oxygen source and bathes face.
4. the dephosphorization treatment method of molten iron as claimed in claim 2 is characterized in that, will be based on the dephosphorization refining agent of CaO, and the plenum system by described gas oxygen source supplies to molten iron with described gas oxygen source and bathes face.
5. as the dephosphorization treatment method of each the described molten iron in the claim 1 to 4, it is characterized in that, the conveying gas of described solid oxygen source is any gas more than a kind or 2 kinds in air, reducing gas, carbonic acid gas, non-oxidizing gas, the rare gas, and oxygen concn is lower than described gas oxygen source.
6. as the dephosphorization treatment method of each the described molten iron in the claim 1 to 4, it is characterized in that described solid oxygen source is any more than a kind or 2 kinds in the agglomerate of granularity below 1mm, roll scale, control of dust powder, iron sand, the iron ore.
7. the dephosphorization treatment method of a molten iron, in converter, dephosphorization refining agent based on CaO is added in the molten iron with oxygen source, what make interpolation forms slag based on the dephosphorization refining agent scorification of CaO, implement dephosphorization treatment with respect to molten iron, it is characterized in that, use the top blast oxygen lance that has 2 feed paths at least, supply with dephosphorization refining agent based on CaO to the molten iron face of bathing with the gas oxygen source from one of them plenum system, from another plenum system, near the position identical with the position of supply gas oxygen source molten iron is bathed face, with air, reducing gas, carbonic acid gas, non-oxidizing gas, any gas more than a kind or 2 kinds in the rare gas is supplied with the solid oxygen source as conveying with gas.
8. as the dephosphorization treatment method of each the described molten iron in the claim 1,2,3,4,7, it is characterized in that, form a plurality of burning-points, supply with the solid oxygen source to the position that is surrounded by described a plurality of burning-points by the supply of gas oxygen source.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005324253 | 2005-11-09 | ||
| JP324253/2005 | 2005-11-09 | ||
| PCT/JP2006/322792 WO2007055404A1 (en) | 2005-11-09 | 2006-11-09 | Method of hot metal dephosphorization treatment |
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|---|---|
| CN101305105A CN101305105A (en) | 2008-11-12 |
| CN101305105B true CN101305105B (en) | 2010-09-08 |
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|---|---|
| KR (1) | KR101001078B1 (en) |
| CN (1) | CN101305105B (en) |
| TW (1) | TW200730636A (en) |
| WO (1) | WO2007055404A1 (en) |
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| WO2014112432A1 (en) * | 2013-01-18 | 2014-07-24 | Ｊｆｅスチール株式会社 | Converter steelmaking process |
| KR101677341B1 (en) * | 2014-12-03 | 2016-11-18 | 주식회사 포스코 | Highly efficient method for hot metal pretreatment |
| WO2018135351A1 (en) * | 2017-01-18 | 2018-07-26 | Ｊｆｅスチール株式会社 | Molten iron dephosphorization method |
| JP6795133B1 (en) * | 2019-03-22 | 2020-12-02 | Ｊｆｅスチール株式会社 | Blow control method and smelt control device for converter type dephosphorization smelting furnace |
| TWI737504B (en) * | 2020-09-28 | 2021-08-21 | 中國鋼鐵股份有限公司 | Dephosphorization method of basic oxygen furnace slag |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS58147506A (en) * | 1982-02-27 | 1983-09-02 | Kawasaki Steel Corp | Preliminary treatment of molten iron |
| JPS5989710A (en) * | 1982-11-11 | 1984-05-24 | Kawasaki Steel Corp | Immersion lance for treatment of molten metal |
| JPS59157209A (en) | 1983-02-25 | 1984-09-06 | Sumitomo Metal Ind Ltd | Pretreatment of molten iron |
| JPS60162712A (en) | 1984-02-02 | 1985-08-24 | Nippon Steel Corp | Method for blowing powder into molten iron |
| JPS61201712A (en) * | 1985-03-02 | 1986-09-06 | Kobe Steel Ltd | Pretreatment of molten pig iron |
| JPH01287213A (en) * | 1988-05-11 | 1989-11-17 | Nkk Corp | Method for reducing cr ore in pre-treatment of molten iron |
| JPH11256217A (en) * | 1998-03-10 | 1999-09-21 | Nippon Steel Corp | Method for supplying auxiliary raw material in converter |
| JP2001131629A (en) * | 1999-11-04 | 2001-05-15 | Nippon Steel Corp | Top-blown lance for dephosphorizing molten iron and dephosphorizing method of molten iron |
| JP2004190101A (en) * | 2002-12-12 | 2004-07-08 | Nippon Steel Corp | Method for pre-treating molten iron |
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- 2006-11-09 KR KR1020087009225A patent/KR101001078B1/en active IP Right Grant
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| TW200730636A (en) | 2007-08-16 |
| KR20080059226A (en) | 2008-06-26 |
| WO2007055404A1 (en) | 2007-05-18 |
| CN101305105A (en) | 2008-11-12 |
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