JPH0920913A - Pretreatment for molten iron - Google Patents
Pretreatment for molten ironInfo
- Publication number
- JPH0920913A JPH0920913A JP18666895A JP18666895A JPH0920913A JP H0920913 A JPH0920913 A JP H0920913A JP 18666895 A JP18666895 A JP 18666895A JP 18666895 A JP18666895 A JP 18666895A JP H0920913 A JPH0920913 A JP H0920913A
- Authority
- JP
- Japan
- Prior art keywords
- slag
- hot metal
- pretreatment
- carbon source
- oxygen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、溶銑予備処理時の温度
降下を低減し、転炉吹錬時の熱的余裕度を向上させるた
めの溶銑を製造する溶銑予備処理方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot metal pretreatment method for producing hot metal for reducing the temperature drop during hot metal pretreatment and for improving the thermal margin during converter blowing.
【０００２】[0002]
【従来の技術】転炉等で行われる精錬処理に際して、こ
れに先立って高炉溶銑成分や溶製鋼種の成分組成に対応
した溶銑予備処理が一般に実施されている。こうした溶
銑予備処理の主たる目的は、脱珪・脱燐・脱硫の予備処
理精錬処理にあるが、その他予備処理工程でＭｎ鉱石を
添加して銑成分を調整することも行われており、これら
の結果として転炉での精錬負荷並びに成分調整負荷を軽
減することができ、転炉では専ら脱炭反応を進行せしめ
ることができる。2. Description of the Related Art Prior to the refining treatment performed in a converter or the like, a hot metal pretreatment is generally carried out prior to the refining treatment in accordance with the blast furnace hot metal composition and the composition of the molten steel species. The main purpose of such hot metal pretreatment is the pretreatment and refining treatment of desiliconization, dephosphorization, and desulfurization, but other pretreatment processes include adding Mn ore to adjust the pig iron component. As a result, the refining load and the component adjusting load in the converter can be reduced, and the decarburization reaction can proceed exclusively in the converter.
【０００３】すなわち転炉精錬を実施するまでに脱燐等
の処理がほぼ完了しているので転炉では、脱燐フラック
ス等の精錬剤の添加が殆ど不必要となり、また予備処理
工程でＭｎ鉱石を添加して溶銑中のＭｎ量を高めること
ができるので転炉では、高価なＭｎ系合金鉄の添加を極
力少なくすることができ、これらの結果、転炉精錬コス
トが大幅に低減するという経済効果を得ることができ
る。こうした要求を解決する技術として、たとえば特開
平２−２２８４１２等に溶銑予備処理時に、脱燐剤と炭
材を混合して溶銑中に吹き込み、処理中に溶銑炭素濃度
低下を低減する方法が開示されている。That is, since the treatment such as dephosphorization is almost completed before the converter refining is performed, it is almost unnecessary to add a refining agent such as dephosphorization flux in the converter, and the Mn ore is preliminarily treated. Since it is possible to increase the amount of Mn in the hot metal in the converter, it is possible to minimize the addition of expensive Mn-based alloy iron in the converter, and as a result, it is possible to significantly reduce the converter refining cost. The effect can be obtained. As a technique for solving such a demand, for example, Japanese Patent Laid-Open No. 2-228412 discloses a method of mixing a dephosphorizing agent and a carbonaceous material and blowing them into the hot metal during the hot metal pretreatment to reduce a decrease in the hot metal carbon concentration during the treatment. ing.
【０００４】[0004]
【発明が解決しようとする課題】このように溶銑予備処
理は多くの利益をもたらすものであるが、その一方溶銑
予備処理過程では、溶銑中珪素（以下Ｓｉと記す）や溶
銑中炭素（以下Ｃと記す）が消費されて、これらの含有
量が低下し過ぎるきらいがあり、転炉における熱源不足
の原因の一つとなっている。そこで熱源不足を補うため
に、転炉精錬における溶銑配合率を高めたり（溶銑の顕
熱は重量な熱源の一つである）、昇熱用炭素源を添加す
る等の対応がとられている。As described above, the hot metal pretreatment brings many benefits. On the other hand, in the hot metal pretreatment process, silicon in hot metal (hereinafter referred to as Si) and carbon in hot metal (hereinafter C Is consumed, and the content of these tends to be too low, which is one of the causes of insufficient heat source in the converter. Therefore, in order to make up for the shortage of heat sources, measures such as increasing the hot metal mixing ratio in converter refining (the sensible heat of the hot metal is one of the heavy heat sources) and adding a carbon source for heating are taken. .
【０００５】しかるに転炉操業において溶銑配合率を高
めるとその分だけ、フラックス等の投入量が制限される
ことになり、いわゆるリターンスクラップバランスが崩
れて生産能力が低下するという問題が発生する。また転
炉における昇熱用炭素源の添加は、炭素源中に不純物と
してふくまれる硫黄（以下Ｓと記す）の混入をまねき、
吹止め鋼中のＳ濃度が高くなる等の問題をひきおこす。
さらに予備処理工程におけるＭｎ鉱石の添加は、溶銑温
度の低下を招いて溶銑配合率を一層高めなければならな
い要因となっており、また添加されたＭｎ鉱石を予備処
理工程で還元する際に、ＳｉやＣが酸化消費されて熱源
成分残存量を一層低下させていることも事実である。However, when the hot metal content is increased in the converter operation, the amount of the flux or the like added is limited by that amount, which causes a problem that the so-called return scrap balance is lost and the production capacity is reduced. In addition, the addition of the carbon source for heating in the converter causes mixing of sulfur (hereinafter referred to as S) contained as an impurity in the carbon source,
It causes problems such as high S concentration in blow-stop steel.
Furthermore, the addition of Mn ore in the pretreatment step causes a decrease in the hot metal temperature and must be a factor to further increase the hot metal blending ratio, and when reducing the added Mn ore in the pretreatment step, Si is added. It is also a fact that C and C are oxidized and consumed to further reduce the residual amount of the heat source component.
【０００６】また、溶銑予備処理中に脱燐剤と炭材を混
合して吹き込む方法は、炭材と脱燐剤にふくまれる酸素
含有物（酸化鉄あるいはスケールあるいは酸素ガス）
が、同一の羽口から吹き込まれることにより、吐出直後
の羽口近傍での炭材と酸素が反応し、炭材の歩留低下お
よび炭材燃焼による局所的な発熱による羽口近傍の耐火
物溶損が著しく低下するという課題があった。一方酸素
との反応により発生した熱の大部分は、ＣＯガス気泡に
とじこめられて、溶銑に着熱することなく系外にすてら
れてしまうという、経済的な無駄が避けられないという
課題があった。Further, the method of mixing and blowing the dephosphorizing agent and the carbonaceous material during the hot metal pretreatment is carried out by oxygen containing substances (iron oxide or scale or oxygen gas) contained in the carbonaceous material and the dephosphorizing agent.
However, when it is blown from the same tuyere, the carbonaceous material and oxygen in the vicinity of the tuyere immediately after the discharge reacts, the yield of the carbonaceous material is reduced, and the refractory near the tuyere due to local heat generation due to carbonaceous material combustion. There was a problem that the melting loss was significantly reduced. On the other hand, most of the heat generated by the reaction with oxygen is trapped in the CO gas bubbles, and is displaced out of the system without adhering to the hot metal. there were.
【０００７】さらに、吹き込まれた炭材のうち飽和Ｃを
越えた分、あるいは未反応のまま浮上してスラグ中に懸
濁した炭材は、スラグ中にキッシュグラファイト、ある
いは炭材粉としてスラグ中に浮遊・懸濁することとな
り、脱燐反応生成物（燐酸化物）としてスラグ中に捕捉
されていた燐酸化物を還元してしまう結果、復燐が助長
され、脱燐効率を悪化させていた。また、スラグ中の懸
濁したグラファイトは、スラグ処理に際して環境問題を
引き起こすという課題もあった。本発明はこうした事情
に着目してなされたものであって、熱源を十分に含有す
る予備処理溶銑の生産方法を開発することによって転炉
精錬における上記問題点を解決するものである。Further, of the injected carbonaceous material, the amount exceeding the saturated C, or the carbonaceous material which has floated unreacted and suspended in the slag is quiescent graphite in the slag, or carbonaceous material in the slag. As a result, the phosphorus oxide trapped in the slag as a dephosphorization reaction product (phosphorus oxide) is reduced, and as a result, rephosphorization is promoted and dephosphorization efficiency is deteriorated. Further, the suspended graphite in the slag has a problem that it causes an environmental problem during the slag treatment. The present invention has been made in view of such circumstances, and solves the above-mentioned problems in converter refining by developing a method for producing pretreated hot metal containing a sufficient heat source.
【０００８】[0008]
【課題を解決するための手段】上記目的は、溶銑の予備
処理として脱燐処理を行うにあたり、脱燐処理中の生成
スラグ中に炭素源を添加すると共に、スラグ中に酸素源
を吹き込んで前記炭素源を燃焼させることを特徴とする
溶銑の予備処理方法によって達成される。また上記目的
は、溶銑の予備処理として脱燐処理を行うにあたり、脱
燐処理中の溶銑および生成スラグ中に炭素源を添加する
と共に、スラグ中に酸素源を吹き込んで前記炭素源を燃
焼させることを特徴とする溶銑の予備処理方法によって
達成される。[Means for Solving the Problems] The above object is to perform a dephosphorization treatment as a pretreatment for hot metal by adding a carbon source to the produced slag during the dephosphorization treatment and blowing an oxygen source into the slag. This is achieved by a hot metal pretreatment method characterized by burning a carbon source. Further, the above-mentioned object is to perform a dephosphorization treatment as a pretreatment of the hot metal, to add a carbon source to the hot metal and the generated slag during the dephosphorization treatment, and to blow an oxygen source into the slag to burn the carbon source. Is achieved by a pretreatment method for hot metal.
【０００９】[0009]
【作用】溶銑中のＣ濃度は飽和点に近く、そのため従来
は溶銑中への炭素源の添加は困難であると考えられてい
た。また精錬に対する従来の常識では、炭素源は還元性
材料であり、これを溶銑予備処理時、特に脱燐処理時あ
るいは脱燐処理後に添加すれば酸化反応である脱燐反応
が阻害され、あるいは復燐反応がおこって脱燐性能が低
下すると考えられていた。このような現状のなかで、た
とえば特開平２−２２８４１２号等において、溶銑中に
炭材を脱燐剤と混合して吹き込む溶銑予備処理方法が開
示されているが、上記課題で記述した理由により実操業
への適用には大きな技術的課題があった。The C concentration in the hot metal is close to the saturation point, and it has been conventionally considered difficult to add a carbon source to the hot metal. Further, according to the conventional wisdom regarding refining, the carbon source is a reducing material, and if this is added during hot metal pretreatment, especially during or after dephosphorization treatment, the dephosphorization reaction, which is an oxidation reaction, may be inhibited or recovered. It was believed that the phosphorus reaction would occur and the dephosphorization performance would decrease. Under such circumstances, for example, Japanese Patent Application Laid-Open No. 2-228412 discloses a hot metal pretreatment method in which a carbonaceous material is mixed with a dephosphorizing agent and blown into the hot metal, but for the reason described above. There were major technical challenges in applying it to actual operations.
【００１０】こうした状況の中で、本発明者らは、前記
課題について、種々の改善検討を実施した結果、予備処
理時に溶銑中に炭材を吹き込むだけの前記方法では、課
題解決方法がなく、操業への適用は困難であるとの結論
を得るに至った。そこで、本発明者らは、予備処理時の
熱源確保という観点から、溶銑中にＣを供給するという
従来の考え方に対して、発想の転換をはかり、処理中の
温度低下を防止するという観点で鋭意検討を重ねた結
果、スラグ中の酸素ポテンシャル低下を引き起こさなけ
れば、スラグ中に炭素源が存在しても復燐反応をおこさ
ずに操業が可能であるという知見を得た。Under these circumstances, the inventors of the present invention conducted various improvement studies on the above-mentioned problems, and as a result, the above-mentioned method of only blowing carbonaceous material into the hot metal at the time of pretreatment does not have a method for solving the problems. We have come to the conclusion that the application to operation is difficult. Therefore, from the viewpoint of securing a heat source during the pretreatment, the present inventors have changed the idea from the conventional idea of supplying C into the hot metal, and from the viewpoint of preventing the temperature drop during the treatment. As a result of earnest studies, it was found that operation can be performed without causing a rephosphorization reaction even if a carbon source is present in the slag as long as the oxygen potential in the slag is not lowered.
【００１１】すなわちスラグ中に炭材が存在した場合の
復燐メカニズムは以下の二段階のステップですすむこと
が熱力学的に証明されている。 スラグ中のＦｅＯが炭素（炭材）により還元される ＦｅＯ＋Ｃ＝Ｆｅ＋ＣＯ スラグ中のＦｅＯが還元され、低減したことによりス
ラグ中の酸素ポテンシャルが低減し、燐分配が悪化した
結果、復燐が発生する。 Ｐ2 Ｏ5 ＝２Ｐ＋５ＯThat is, it has been thermodynamically proved that the re-phosphorization mechanism when carbonaceous material is present in the slag can be accomplished by the following two steps. FeO in slag is reduced by carbon (carbonaceous material) FeO + C = Fe + CO FeO in slag is reduced and reduced to reduce oxygen potential in the slag and deteriorate phosphorus distribution, resulting in reconstitution of phosphorus. . P 2 O 5 = 2P + 5O
【００１２】実操業時において、スラグ中に炭素が存在
した場合に復燐するように観察されるが、熱力学上は、
スラグ中のＰ2 Ｏ5 がＣで直接還元される、 Ｐ2 Ｏ5 ＋５Ｃ＝２Ｐ＋５ＣＯ という反応は起こりえない。したがって、本発明者ら
は、スラグ中におけるＣの存在によるＦｅＯの低下を抑
制すれば、スラグ中にＣが存在しても復燐反応は起こら
ないという考えの基に、積極的にスラグ中に炭素源を供
給し、その炭素源をスラグ中で燃焼させて溶銑に着熱さ
せることにより、処理中の溶銑温度低下抑制方法を発明
した。In actual operation, when carbon is present in the slag, it is observed to re-phosphorize, but thermodynamically,
The reaction of P 2 O 5 + 5C = 2P + 5CO in which P 2 O 5 in the slag is directly reduced by C cannot occur. Therefore, the inventors of the present invention positively consider that if the reduction of FeO due to the presence of C in the slag is suppressed, the rephosphorization reaction does not occur even if C is present in the slag. A method for suppressing a decrease in hot metal temperature during treatment is invented by supplying a carbon source and burning the carbon source in slag to heat the hot metal.
【００１３】以下本発明方法をさらに詳細に説明する。
すなわち本発明の第１の方法では、溶銑の予備処理とし
て脱燐処理を行うにあたり、脱燐処理中の生成スラグ中
に炭素源を添加すると共に、スラグ中に酸素源を吹き込
んで前記炭素源を燃焼させて、その燃焼熱を溶銑に着熱
させるものである。前述したように、スラグ中に炭素が
存在する場合は、見かけ上スラグ中に存在する炭素によ
り燐酸化物が還元されて復燐が発生する。しかし、その
メカニズムは炭素によるＦｅＯ還元が直接原因であり、
その結果としてスラグ中酸素ポテンシャルが低下するこ
とにより復燐が発生しているものである。The method of the present invention will be described in more detail below.
That is, in the first method of the present invention, when performing the dephosphorization treatment as a pretreatment of the hot metal, a carbon source is added to the produced slag during the dephosphorization treatment, and an oxygen source is blown into the slag to remove the carbon source. It is burned and the heat of combustion is applied to the hot metal. As described above, when carbon is present in the slag, the phosphorus oxide is apparently reduced by the carbon present in the slag, and recondensation occurs. However, the mechanism is directly due to FeO reduction by carbon,
As a result, the oxygen potential in the slag is lowered and re-phosphorus is generated.
【００１４】本発明者等は、元来スラグ中に粒鉄分（以
下メタリックＦｅ：Ｍ−Ｆｅ）が約１０％程度存在して
いることに着目し、そのＭ−Ｆｅに酸素源を供給して炭
素によるＦｅＯ還元量以上のＦｅＯ量を生成させること
により、結果としてＦｅＯ還元を防止できることを発見
した。図１にスラグ中に炭素源（コークス）と酸素源
（酸素ガス）を供給した場合のスラグ酸素ポテンシャル
の調査結果を示す。化学量論的等価のコークスと酸素を
供給しているにもかかわらず、スラグ中のＦｅＯが増加
し、一方スラグ中のＭ−Ｆｅが低減しており、Ｍ−Ｆｅ
酸化により、もともとスラグ中に存在したＦｅＯが還元
される以上の量のＭ−Ｆｅ酸化によるＦｅＯ供給（酸素
ポテンシャル向上）が可能であることが判明した。した
がって、スラグ中に炭素源を供給すると共に、スラグ中
に酸素源を吹き込むことにより、脱燐の悪化なしに炭素
源の燃焼が可能となり、溶銑への着熱が得られる。The present inventors have noticed that about 10% of granular iron content (hereinafter metallic Fe: M-Fe) originally exists in the slag, and an oxygen source is supplied to the M-Fe. It was discovered that the FeO reduction can be prevented as a result by producing a FeO amount larger than the FeO reduction amount by carbon. Figure 1 shows the results of an investigation of the slag oxygen potential when a carbon source (coke) and an oxygen source (oxygen gas) were supplied into the slag. Despite supplying stoichiometrically equivalent coke and oxygen, FeO in the slag is increasing, while M-Fe in the slag is decreasing.
It has been found that it is possible to supply FeO (improve oxygen potential) by oxidizing M-Fe in an amount more than the amount of FeO originally present in the slag is reduced by the oxidation. Therefore, by supplying the carbon source into the slag and blowing the oxygen source into the slag, the carbon source can be burned without deteriorating the dephosphorization, and the heat of the hot metal can be obtained.
【００１５】第２の方法は、従来の方法では、Ｃ飽和に
よるスラグ中へのグラファイト析出の課題があり、飽和
まで溶銑中にＣを吹き込むことが不可能であった。しか
し本発明では、スラグ中への供給酸素量を適当な量とし
て設定することにより、スラグ中に析出することの懸念
なしに、溶銑中に飽和するまでＣを吹き込むことが可能
となる。さらに、スラグ中への供給酸素量および吹き込
み条件を適当な条件とすることにより、スラグ中への酸
素供給をＭ−ＦｅおよびスラグへのＣ供給量より十分大
きな値とすることにより、溶銑中の脱炭を促進し、脱炭
分を溶銑中に吹き込んで供給することにより、溶銑Ｃの
低下なしにＣ燃焼による温度上昇をえることが可能とな
り、第１の方法をさらに効果的なものとすることができ
る。In the second method, the conventional method has a problem of graphite precipitation in the slag due to C saturation, and it was impossible to blow C into the hot metal until saturation. However, in the present invention, by setting the amount of oxygen to be supplied to the slag as an appropriate amount, it becomes possible to blow C into the hot metal until it is saturated without fear of precipitation in the slag. Furthermore, by setting the oxygen supply amount into the slag and the blowing condition to appropriate conditions, the oxygen supply into the slag is set to a value sufficiently larger than the C supply amount to M-Fe and the slag, thereby By promoting decarburization and supplying the decarburized component by blowing it into the hot metal, it is possible to increase the temperature by C combustion without lowering the hot metal C, which makes the first method more effective. be able to.
【００１６】上記方法は、Ｃ燃焼により多量のＣＯガス
が発生することから、スラグ中をＣＯガスが通過する際
にスラグのフォーミングを引き起こす。その防止策とし
て、フォーミングしたスラグを収容可能な反応槽を使用
することが必要であり、本発明にかかる予備処理方法実
施の際は、溶銑鍋に払い出された溶銑中にフリーボード
を浸漬した反応容器あるいは、転炉を使用することが必
要である。該反応容器に混銑車を使用した場合も本発明
法にかかるスラグ中への炭素源と酸素源の供給による溶
銑への熱付与が可能であるが、送酸速度低下等のフォー
ミング対策が必要である。In the above method, a large amount of CO gas is generated by C combustion, so that the slag is formed when the CO gas passes through the slag. As a preventive measure, it is necessary to use a reaction tank capable of accommodating the formed slag, and at the time of carrying out the pretreatment method according to the present invention, the freeboard was immersed in the hot metal discharged to the hot metal ladle. It is necessary to use a reaction vessel or converter. Even when a hot metal wheel is used in the reaction vessel, it is possible to apply heat to the hot metal by supplying the carbon source and the oxygen source into the slag according to the method of the present invention, but it is necessary to take a forming countermeasure such as a decrease in the oxygen transfer rate. is there.
【００１７】また前記炭素源としては、炭素含有量が高
いほど効率および炭素供給速度を早くできるという点
で、コークスまたは石炭であることが望ましい。粒径
は、細粒であるほど反応速度が早くなり、反応効率が向
上すると言う点で、例えば最大粒径５ｍｍといった粒径
の細かいものほど望ましい。さらに前記酸素源として
は、反応的には純酸素がもっとも望ましい。あるいはス
ラグ中への酸素源供給ノズル近傍または耐火物の溶損等
の状況により、冷却用希釈ガスとして、窒素ガスを混合
した酸素ガスと窒素ガスを主成分とする混合ガスが望ま
しい（空気も含む）。窒素ガスの配合割合は、ノズル材
質・構造（水冷または冷却なし等）の必要冷却能力によ
り、適正な配合を選択することが必要である。The carbon source is preferably coke or coal in that the higher the carbon content, the higher the efficiency and the higher the carbon supply rate. The finer the particle size, the faster the reaction rate and the higher the reaction efficiency. Therefore, the smaller the particle size, for example, the maximum particle size of 5 mm, the more desirable. Further, as the oxygen source, pure oxygen is most desirable in terms of reaction. Alternatively, depending on the conditions such as the vicinity of the oxygen source supply nozzle into the slag or the melting of refractories, etc., it is desirable to use a mixed gas containing oxygen gas mixed with nitrogen gas and nitrogen gas as the main components (including air) as the diluent gas for cooling. ). As for the mixing ratio of nitrogen gas, it is necessary to select an appropriate mixing depending on the required cooling capacity of the nozzle material and structure (water cooling or no cooling, etc.).
【００１８】[0018]
【実施例】表１および表２に示す成分組成ならびに温度
の溶銑に対し、表記の条件で脱珪処理をおこない、処理
後の溶銑成分・温度を調べたところ、表１、表２に示す
結果が得られた。従来に比較し、スラグ中へ炭材を添加
し、酸素源によりスラグ中で燃焼させることにより、発
生した熱を溶銑に着熱させて処理中の温度降下を低減
し、結果的に処理後温度の向上・転炉での熱裕度向上を
実現できた。その際の燃焼熱量の溶銑への着熱比率は、
図２に示すように約２０から７０％であった。ただし、
スラグへの純炭素換算供給量は、下記のように定義す
る。 スラグへの純炭素換算供給量＝溶銑中への純炭素供給量
−（溶銑の飽和〔Ｃ〕−溶銑〔Ｃ〕）×溶銑量[Examples] Hot metal components having the compositions and temperatures shown in Tables 1 and 2 were subjected to a desiliconization treatment under the indicated conditions, and the hot metal components and temperatures after the treatment were examined. The results shown in Tables 1 and 2 were obtained. was gotten. Compared to the conventional method, by adding carbonaceous material to the slag and burning it in the slag with an oxygen source, the generated heat is absorbed by the hot metal to reduce the temperature drop during processing, resulting in a post-treatment temperature. We were able to improve the heat tolerance of the converter. At that time, the ratio of the heat of combustion to the hot metal is
As shown in FIG. 2, it was about 20 to 70%. However,
The pure carbon equivalent supply to the slag is defined as follows. Supply amount of pure carbon converted to slag = Supply amount of pure carbon into hot metal- (Saturation of hot metal [C] -Hot metal [C]) x Hot metal amount
【００１９】[0019]
【表１】 [Table 1]
【００２０】[0020]
【表２】 [Table 2]
【００２１】炭材燃焼用ガスの吹き込み用は、その含有
する酸素分に換算して、下記（１）式に示すスラグ中へ
の炭素純分（炭材量×Ｃ含有率）を燃焼するに等価な量
が適当であるが、（１）式で計算される量に対して＋１
００％〜−４０％までは本方法が適用可能である。＋１
００％を越えて酸素を供給すると、投入した炭素分がＣ
Ｏ2 まで完全燃焼してもなお余剰となる酸素が発生する
こととなり、結果的に鉄酸化に消費されることとなるた
めに、鉄歩留の悪化を招く。一方−４０％以下では、ス
ラグ中にＣ分が残留し、キッシュグラファイト析出によ
りスラグ処理ができない等の操業に重大な影響を及ぼす
ことから不適当である。 Ｃ＋Ｏ＝ＣＯ ・・・（１）For blowing carbonaceous material combustion gas, it is necessary to convert the oxygen content of the carbonaceous material to burn pure carbon content (carbonaceous material content × C content ratio) in the slag represented by the following formula (1). An equivalent amount is appropriate, but +1 for the amount calculated by equation (1)
This method can be applied from 00% to -40%. +1
When oxygen is supplied in excess of 00%, the input carbon content becomes C
Even if O 2 is completely burned, excess oxygen will still be generated, and as a result, it will be consumed for iron oxidation, resulting in deterioration of iron yield. On the other hand, if it is -40% or less, the C content remains in the slag and the slag treatment cannot be performed due to the precipitation of quiche graphite. C + O = CO ... (1)
【００２２】（１）式をもとに算出され、上記範囲に示
された範囲の酸素量を供給して操業した結果、従来の溶
銑中に炭素源を添加した際に課題となっていたスラグへ
のキッシュグラファイト析出の発生も全くなく、脱硅ス
ラグの処置も従来方法を変更する必要はなかった。炭材
燃焼用ガスの供給は、上吹でスラグ中にガスを供給する
方法、または脱硅剤インジェクション法においては、イ
ンジェクションランスのスラグ位置にガス吹き込み用ノ
ズルを新たに設置して、スラグ中にガスを吹き込む方法
または、炭材燃焼用ガス専用のランスをガス吐出ノズル
の位置がスラグ位置になるように設置する方法のいずれ
か、または２つ以上の方法を組み合わせて実施してもよ
い。The slag, which was calculated based on the equation (1) and was operated by supplying an oxygen amount in the range shown above, was a problem when a carbon source was added to the conventional hot metal. No precipitation of quiche graphite was found at all, and there was no need to change the conventional method for the treatment of desiliconized slag. Supply of carbonaceous material combustion gas is a method of supplying gas into the slag by top blowing, or in the desiliconizing agent injection method, a gas injection nozzle is newly installed at the slag position of the injection lance, Either a method of blowing gas or a method of installing a lance dedicated to carbonaceous material combustion gas so that the position of the gas discharge nozzle is at the slag position, or a combination of two or more methods may be carried out.
【００２３】また、フリーボードを使用することによ
り、スラグ中での炭素源燃焼の際発生するＣＯガスによ
るスラグフォーミングによる操業への影響なしに実施す
ることが可能となった。転炉を使用した際には、その特
性である大きな炉内フリーボードの機能を十分活用でき
るため、さらに安定した操業が実現できる。表１，２の
実施例では炭素源として粉コークスのみを表記したが、
石炭を使用しても同等の効果が得られる。また、使用す
る炭素源の粒度は、集塵系に飛散することによるロスの
ない範囲で、細粒であるほど反応効率が向上、あるいは
反応速度向上の効果が得られる。Further, by using the freeboard, it becomes possible to carry out the operation without affecting the operation due to the slag forming due to the CO gas generated during the combustion of the carbon source in the slag. When the converter is used, the function of the large freeboard in the furnace, which is its characteristic, can be fully utilized, and thus more stable operation can be realized. In the examples of Tables 1 and 2, only the powder coke was described as the carbon source,
The same effect can be obtained using coal. Further, the particle size of the carbon source used is within a range in which there is no loss due to scattering into the dust collecting system, and the finer the particles, the higher the reaction efficiency or the reaction rate.
【００２４】また、スラグ中炭素源燃焼に使用するガス
としては、酸素ガスあるいは酸素ガスと窒素ガスの混合
ガスが望ましいが、その中の窒素ガスは酸素ガスの希釈
ガスとしての役割をはたしており、炭素と反応せずに火
点近傍の冷却を実現するためであるならば、窒素ガスに
代替して例えばＡｒやＣＯ2 ガスを使用することにより
同等の効果が得られる。ただし、ガスコスト上昇を引き
起こすため、工業生産的には窒素ガスが最も望ましい。
本発明法における予備処理方法は、表１，２で示すが如
く脱燐処理の前に脱硅処理を行う場合のみならず、脱燐
処理の前に脱硅処理を行いかつ脱燐処理の前、あるいは
後に脱硫処理を行う場合においても適用可能である。As the gas used for burning the carbon source in the slag, oxygen gas or a mixed gas of oxygen gas and nitrogen gas is desirable, and the nitrogen gas therein serves as a dilution gas of oxygen gas, In order to realize cooling near the fire point without reacting with carbon, the same effect can be obtained by using, for example, Ar or CO 2 gas instead of nitrogen gas. However, nitrogen gas is most desirable for industrial production because it causes an increase in gas cost.
As shown in Tables 1 and 2, the pretreatment method in the method of the present invention is not limited to the case where the dephosphorization treatment is performed before the dephosphorization treatment, but the dephosphorization treatment is performed before the dephosphorization treatment and before the dephosphorization treatment. Alternatively, it can be applied when desulfurization treatment is performed later.
【００２５】[0025]
【発明の効果】本発明は、以上のような手段をとるもの
であり、製鋼工程における熱源（溶銑予備処理後の温
度）向上を実現した結果、転炉におけるＭｎ鉱石投入量
増大による吹止Ｍｎ向上と、高価なＦｅ−Ｍｎ合金鉄使
用量削減という点で、多大な経済的効果を得ることが可
能となった。EFFECTS OF THE INVENTION The present invention takes the above means, and as a result of improving the heat source (temperature after hot metal pretreatment) in the steelmaking process, blown Mn due to an increase in the Mn ore input in the converter. It has become possible to obtain a great economic effect in terms of improvement and reduction of the amount of expensive Fe—Mn alloy iron used.
【図１】スラグ中に炭素源と酸素源を供給した際のスラ
グ酸素ポテンシャルを示す図FIG. 1 is a diagram showing a slag oxygen potential when a carbon source and an oxygen source are supplied into the slag.
【図２】スラグへの炭素供給量と処理中温度降下低減代
を示す図FIG. 2 is a diagram showing the amount of carbon supplied to the slag and the allowance for reducing the temperature drop during processing.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 金子 敏行 大分県大分市大字西ノ洲１番地 新日本製 鐵株式会社大分製鐵所内 (72)発明者 柏原 司 大分県大分市大字西ノ洲１番地 新日本製 鐵株式会社大分製鐵所内 (72)発明者 森口 誠 大分県大分市大字西ノ洲１番地 新日本製 鐵株式会社大分製鐵所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Kaneko 1 Nishinosu, Oita City, Oita Pref. Nippon Steel Co., Ltd. Oita Steel Works (72) Inventor, Kashiwabara 1 Nishinozu, Oita City, Oita Pref. (72) Inventor Makoto Moriguchi 1st Nishinosu, Oita-shi, Oita New Nippon Steel Co., Ltd. Oita Steel Co., Ltd.
Claims (2)
あたり、脱燐処理中の生成スラグ中に炭素源を添加する
と共に、スラグ中に酸素源を吹き込んで前記炭素源を燃
焼させることを特徴とする溶銑の予備処理方法。1. When performing a dephosphorization treatment as a pretreatment for hot metal, a carbon source is added to the produced slag during the dephosphorization treatment, and an oxygen source is blown into the slag to burn the carbon source. Pretreatment method for hot metal.
あたり、脱燐処理中の溶銑および生成スラグ中に炭素源
を添加すると共に、スラグ中に酸素源を吹き込んで前記
炭素源を燃焼させることを特徴とする溶銑の予備処理方
法。2. When performing a dephosphorization treatment as a pretreatment of the hot metal, a carbon source is added to the hot metal and the generated slag during the dephosphorization treatment, and an oxygen source is blown into the slag to burn the carbon source. A method for pretreatment of hot metal, characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18666895A JP3577365B2 (en) | 1995-06-30 | 1995-06-30 | Hot metal pretreatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18666895A JP3577365B2 (en) | 1995-06-30 | 1995-06-30 | Hot metal pretreatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0920913A true JPH0920913A (en) | 1997-01-21 |
| JP3577365B2 JP3577365B2 (en) | 2004-10-13 |
Family
ID=16192578
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18666895A Expired - Fee Related JP3577365B2 (en) | 1995-06-30 | 1995-06-30 | Hot metal pretreatment method |
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| Country | Link |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013057927A1 (en) | 2011-10-17 | 2013-04-25 | Ｊｆｅスチール株式会社 | Powder injection lance and method of refining molten iron using said powder injection lance |
| WO2013145686A1 (en) | 2012-03-29 | 2013-10-03 | Ｊｆｅスチール株式会社 | Method for refining hot metal in converter |
-
1995
- 1995-06-30 JP JP18666895A patent/JP3577365B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013057927A1 (en) | 2011-10-17 | 2013-04-25 | Ｊｆｅスチール株式会社 | Powder injection lance and method of refining molten iron using said powder injection lance |
| US9580764B2 (en) | 2011-10-17 | 2017-02-28 | Jfe Steel Corporation | Top-blowing lance and method for refining molten iron using the same |
| WO2013145686A1 (en) | 2012-03-29 | 2013-10-03 | Ｊｆｅスチール株式会社 | Method for refining hot metal in converter |
| KR20140133602A (en) | 2012-03-29 | 2014-11-19 | 제이에프이 스틸 가부시키가이샤 | Method for refining hot metal in converter |
| US9957581B2 (en) | 2012-03-29 | 2018-05-01 | Jfe Steel Corporation | Method for refining hot metal in converter |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3577365B2 (en) | 2004-10-13 |
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