JP3525766B2 - Hot metal dephosphorization method - Google Patents
Hot metal dephosphorization methodInfo
- Publication number
- JP3525766B2 JP3525766B2 JP30219998A JP30219998A JP3525766B2 JP 3525766 B2 JP3525766 B2 JP 3525766B2 JP 30219998 A JP30219998 A JP 30219998A JP 30219998 A JP30219998 A JP 30219998A JP 3525766 B2 JP3525766 B2 JP 3525766B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- hot metal
- amount
- cao
- concentration
- 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.)
- Expired - Fee Related
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Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、ＣａＯ粉、Ａｌ2
Ｏ3 粉およびＦｅ2 Ｏ3 粉を含有する混合粉を酸素ガス
と共に溶銑に吹き付けて行う溶銑の脱りん方法に関す
る。
【０００２】
【従来の技術】近年、鋼材に対する品質要求が高度化
し、低りん鋼に対する需要が増大しているが、予備処理
として熱力学的に脱りん処理が有利な溶銑段階で脱りん
する方法が種々開発されている。
【０００３】たとえば特公平３−７７２４６号公報に
は、上底吹き転炉を用いる方法が開示されており、近年
上底吹き転炉を用いた溶銑脱りん法がコスト合理化策と
して適用拡大されてきている。また、スラグ処理に係わ
る環境問題から、製鋼スラグの発生量低減が求められて
いるが、同公報には、製鋼段階で発生するスラグ量を低
減できる方法が開示されている。
【０００４】しかしながら、同公報に開示された方法
は、塊状のフラックスを用いるため、スラグの滓化を安
定しておこなうのが困難であり、滓化促進剤としてホタ
ル石等のハロゲン化物を使用するため、耐火物の溶損量
を増大させるという問題点があった。
【０００５】この課題を解決する方法として、特開平８
−３１１５２３号公報にはホタル石等の滓化促進剤を用
いずに、ＣａＯ粉のみを上吹き酸素と共に溶銑に吹き付
けて溶銑脱りんを行う方法が開示されている。この方法
は滓化し易い粉状のＣａＯを上吹き添加して、同時に添
加する酸素で生成するＦｅＯおよび火点での温度上昇に
よって滓化促進ができるので、ホタル石等を使用せずと
も溶銑脱りん処理ができ、しかも発生スラグ量を大幅に
低減できるとしている。
【０００６】しかし、同公報に開示の方法では、溶銑中
の［Ｓｉ］濃度が０．３０％を超えて高い場合、溶銑脱
りんの処理に初期の脱Ｓｉ反応で発生する熱によりフラ
ックスが溶融し、生成したＳｉＯ2 とＣａＯ粉および上
吹きした酸素により生成したＦｅＯとが反応し脱りん能
のある低融点スラグが形成できるが、溶銑中の［Ｓｉ］
濃度が０．３０％以下の場合、熱源不足のためフラック
スの滓化率が低くなるという問題点があった。
【０００７】溶銑中の［Ｓｉ］濃度が低い方が、少ない
ＣａＯ量で脱りん能力の高い高塩基度（ＣａＯ／ＳｉＯ
2 ）のスラグを形成できるので、脱りんスラグの発生量
を低減できる。
【０００８】そのため、高炉から出た溶銑に酸化鉄等の
脱Ｓｉ剤を添加し、溶銑中の［Ｓｉ］濃度が０．１５％
以下まで脱Ｓｉ処理を行っている。この低Ｓｉ濃度の状
態でも脱りん処理を可能とするために、ＣａＯの滓化促
進が重要であり、その技術確立が望まれていた。
【０００９】
【発明が解決しようとする課題】本発明の目的は、溶銑
中の［Ｓｉ］濃度が０．１５％以下の低レベルにおいて
も、溶銑脱りん時にホタル石等を用いること無く、短時
間吹錬で十分に安定したＣａＯの滓化とＦｅＯが確保で
き、少量の高塩基性スラグで、溶銑中の［Ｐ］濃度を安
定して０．０２５％以下にする方法を提供することにあ
る。
【００１０】
【課題を解決するための手段】本発明者らは、以下の
（Ａ）〜（Ｃ）の知見を得た。
（Ａ）脱りんスラグ中の（ＦｅＯ）は次のような過程で
形成される。上吹き酸素により火点で溶銑が酸化され、
一旦ＦｅＯが生成するが、この時、その近傍に吹き込ま
れたＣａＯ粉とＡｌ2 Ｏ3 粉が存在すればこれらと反応
し、スラグ中の（ＦｅＯ）となる。
【００１１】しかしながら、吹き込まれたＣａＯ粉とＡ
ｌ2 Ｏ3 粉は、酸素ガスの到達深さより深く進入し易
く、必ずしもＦｅＯの生成する場所と一致しない。酸素
により生成する火点の温度は２０００℃以上と推定さ
れ、生成したＦｅＯが単独で存在していると、溶銑中の
［Ｃ］で極めて容易に下記式のように還元される。
【００１２】［Ｃ］＋ＦｅＯ＝Ｆｅ＋ＣＯ
従って、僅かな操業条件の差（ランス高さの変動、フラ
ックス添加速度の変動等）で脱りんスラグ中の（Ｆｅ
Ｏ）濃度が変動し、安定した脱りん処理をすることが困
難となる。（Ｂ）脱りんスラグ中の（ＦｅＯ）濃度を安
定化させる手段として、ＣａＯ粉とＡｌ2 Ｏ3 粉に、さ
らにＦｅ2 Ｏ3 粉を加えた混合フラックスを酸素ガスと
共に溶銑に上吹きする方法が有効である。
【００１３】（Ｃ）Ｆｅ2 Ｏ3 粉を加えた実験を繰り返
した結果、脱りんスラグ中の（ＦｅＯ）濃度を高位安定
化でき、溶銑中の［Ｐ］濃度を０．０２５％以下に低位
安定化できる。
【００１４】本発明は、以上の知見にもとづいて成され
たもので、その要旨は、「上底吹き転炉形式の炉に収容
された［Ｓｉ］濃度０．１５％以下の溶銑に対し、上吹
き酸素ランスよりＣａＯ粉、Ａｌ２ Ｏ３ 粉およびＦ
ｅ２ Ｏ３ 粉を含有する粒径１５〜１５０μｍの混合
粉を吹き付ける際、該混合粉のＡｌ２ Ｏ３ 粉の混合
割合が、ＣａＯ粉添加量の３〜２０％であり、かつＦｅ
２ Ｏ３ 粉混合割合がＣａＯ粉添加量の５〜５０％で
あり、キャリアーガスとして酸素を該溶銑１ｔｏｎ当た
り０．５〜２．０Ｎｍ３ ／ｍｉｎの添加速度で、前記
上吹きランスから吹き付けるとともに、前記上底吹き転
炉形式の炉底から攪拌用ガスを溶銑１ｔｏｎ当たり０．
０５〜０．６０Ｎｍ３ ／ｍｉｎの添加速度で、吹き込
むことを特徴とする溶銑の脱りん方法。」である。
【００１５】
【発明の実施の形態】本発明において使用するＣａＯの
量は、溶銑１ｔｏｎ当たり５〜３０ｋｇであるが、この
量は処理すべき溶銑中の［Ｐ］濃度と目標とする処理後
の溶銑中の［Ｐ］濃度、および溶銑中の［Ｓｉ］濃度に
よって決定される。
【００１６】溶銑中の［Ｓｉ］濃度が０．１５％以下の
溶銑を脱りんする場合のＡｌ2 Ｏ3使用量は、使用する
ＣａＯ量の３％〜２０％が適当である。
【００１７】３％未満では、Ａｌ2 Ｏ3 添加によるフラ
ックスの滓化促進効果が得られない。２０％を超える
と、スラグ中のＣａＯ活量が低下するので、スラグの脱
りん能力が低下する。好ましくは、５〜１５％である。
【００１８】溶銑中の［Ｓｉ］濃度が０．１５％以下の
溶銑を脱りんする場合の上吹きランスから溶銑に吹き付
けられるＦｅ2 Ｏ3 の量は、使用するＣａＯ量の５〜５
０％が適当である。
【００１９】５％未満では、脱りんスラグ中の（Ｆｅ
Ｏ）濃度がＴ．Ｆｅ換算で、７〜２５％という目標レベ
ルになり難く、５０％を超えて多く添加し過ぎると、脱
りんスラグがフォーミングし易くなり、スロッピング等
が発生し、操業に支障が出るからである。
【００２０】上吹き酸素と共に添加されるＣａＯ、Ａｌ
2 Ｏ3 およびＦｅ2 Ｏ3 の粒径は１５〜１５０μｍが適
当である。その理由は、１５μｍ未満では添加時に系外
への飛散が多くなり歩留まり低下のおそれがあり、１５
０μｍを超えるとそれぞれの反応性が低下するおそれが
あるからである。好ましくは３０〜１００μｍである。
【００２１】ＣａＯは製鋼工場で従来から使用している
生石灰でよい。Ａｌ2 Ｏ3 はボーキサイトが多く使用さ
れるが、耐火物を粉砕したものでもよい。Ｆｅ2 Ｏ3 は
粉状の鉄鉱石がよく、酸素キャリアーで添加するのでス
ケール等の酸化され易いものは供給配管内で酸化発熱す
る可能性があり好ましく無い。
【００２２】酸素と共にＦｅ2 Ｏ3 粉を上吹きするに際
し、スピッティングが発生しやすいが、スピッティング
量を軽減するために、Ｆｅ2 Ｏ3 を炉内に予め上置きす
ることが好ましい。なお、このときの上置きＦｅ2 Ｏ3
の量は、本発明でいう混合粉の混合割合には合算しな
い。
【００２３】上置き量は熱バランスから決定されるが、
少なくとも溶銑ｔｏｎ当たり３ｋｇ添加することが望ま
しい。スピッティング量を軽減するためには、Ｆｅ2 Ｏ
3 のように溶融し易いものを使用するのが好ましいが、
ドロマイト等の溶融し難いものでも構わない。
【００２４】上吹き酸素量は、目標の溶銑中の［Ｐ］濃
度レベル、［Ｓｉ］濃度レベルによって異なるが、溶銑
１ｔｏｎ当たり、５から１０Ｎｍ3 程度必要であり、５
〜１０分間で上吹きするために吹き込み流量としては、
溶銑１ｔｏｎ当たり０．５〜２．０Ｎｍ3 ／ｍｉｎがよ
い。
【００２５】炉底から吹き込む攪拌用ガスとしては、Ａ
ｒ、Ｎ2 、ＣＯ2 、ＣＯ、Ｏ2 、炭化水素等の一種以上
を用いることができる。その流量としては、溶銑１ｔｏ
ｎ当たり、０．０５〜０．６Ｎｍ3 ／ｍｉｎが好まし
い。
【００２６】攪拌ガス流量が０．０５Ｎｍ3 ／ｍｉｎ未
満であると、反応速度が高くならず、処理時間内に目標
の溶銑中の［Ｐ］濃度レベルまで脱りん反応が進行しな
いおそれがある。逆に、０．６Ｎｍ3 ／ｍｉｎを超える
と、スラグ中の（ＦｅＯ）が溶銑中の［Ｃ］により還元
され、脱りんが悪化するからである。
【００２７】
【実施例】表１に示す本発明例は、以下の条件下で１０
チャージ実験を行い評価した。溶銑処理前の成分
（［Ｃ］：約４．５％、［Ｓｉ］：０．１３〜０．１５
％、［Ｐ］：０．１０％）、脱りん処理前温度１３２０
〜１３３０℃の予備脱珪処理した溶銑２５０ｔｏｎを上
底吹き転炉に注銑し、炉底羽口からＣＯ2 を溶銑１ｔｏ
ｎ当たり０．３０Ｎｍ3 ／ｍｉｎ吹き込みながら、鉄鉱
石７ｋｇ／ｔｏｎを上置き添加した。
【００２８】その後、３孔ストレートランスを用い、溶
銑１ｔｏｎ当たり１．０Ｎｍ3 ／ｍｉｎの酸素と共に、
２００メッシュアンダーのＣａＯ粉：１５ｋｇ／ｔｏ
ｎ、Ａｌ2 Ｏ3 粉：１．５ｋｇ／ｔｏｎ（ＣａＯ粉添加
量の１０％）、およびＦｅ2 Ｏ3 粉：５ｋｇ／ｔｏｎ
（ＣａＯ粉添加量の約３０％）を混合した脱りんフラッ
クスを７分間溶銑に吹き付けた。処理後の溶銑温度は、
１３４０〜１３５０℃であった。
【００２９】
【表１】
【００３０】表２に示す比較例は、本発明例と同じ溶銑
を使用し吹錬・攪拌条件も同じであるが、酸素と共に上
吹きするフラックス中にＦｅ2 Ｏ3 粉を入れないＣａＯ
粉：１５ｋｇ／ｔｏｎ、Ａｌ2 Ｏ3 粉：１．５ｋｇ／ｔ
ｏｎ（ＣａＯ粉添加量の１０％）の条件下で１０チャー
ジ実験を行い評価した。
【００３１】Ｆｅ2 Ｏ3 の全添加量を本発明例の場合と
合わせるため、初期上置きするＦｅ2 Ｏ3 量を１２ｋｇ
／ｔｏｎとした。
【００３２】
【表２】【００３３】表１と表２とを比較すると、本発明例のほ
うが比較例より、脱りんスラグ中の（Ｔ．Ｆｅ）濃度が
高位に安定しており、処理後の溶銑中の［Ｐ］濃度も低
位に安定した結果が得られた。
【００３４】
【発明の効果】本発明によれば、溶銑中の［Ｓｉ］濃度
が０．１５％以下の低レベルにおいても、溶銑脱りん時
にホタル石等を用いること無く、短時間吹錬で十分に安
定したＣａＯの滓化とＦｅＯが確保でき、少量の高塩基
性スラグで溶銑中の［Ｐ］濃度を安定して０．０２５％
以下にすることができる。Description: TECHNICAL FIELD [0001] The present invention relates to CaO powder, Al 2
The present invention relates to a method for dephosphorizing hot metal by spraying a mixed powder containing O 3 powder and Fe 2 O 3 powder together with oxygen gas onto hot metal. 2. Description of the Related Art In recent years, quality requirements for steel materials have been advanced and demand for low-phosphorus steel has been increasing. However, as a pretreatment, a method of dephosphorizing at a hot metal stage where dephosphorization is thermodynamically advantageous. Have been developed. [0003] For example, Japanese Patent Publication No. 3-77246 discloses a method using an upper-bottom blown converter, and in recent years, hot metal dephosphorization using an upper-bottom blown converter has been expanded as a cost rationalizing measure. ing. In addition, due to environmental problems related to slag treatment, it is required to reduce the amount of steelmaking slag generated. This publication discloses a method capable of reducing the amount of slag generated in the steelmaking stage. However, the method disclosed in the publication uses a massive flux, so that it is difficult to stably convert slag into slag, and a halide such as fluorite is used as a slag formation accelerator. Therefore, there is a problem that the amount of erosion of the refractory is increased. [0005] To solve this problem, Japanese Patent Laid-Open No.
JP-A-3111523 discloses a method of performing hot metal dephosphorization by blowing only CaO powder onto hot metal together with top-blown oxygen without using a slagging accelerator such as fluorite. In this method, powdered CaO, which is easy to form slag, is blown upward, and slag formation can be accelerated by FeO generated simultaneously with added oxygen and a temperature rise at a flash point. Therefore, hot metal removal can be performed without using fluorite or the like. It states that phosphorus treatment can be performed and the amount of generated slag can be significantly reduced. However, according to the method disclosed in the publication, when the [Si] concentration in the hot metal is higher than 0.30%, the flux is melted by heat generated in the initial de-Si reaction in the hot metal dephosphorization treatment. Then, the generated SiO 2 reacts with the CaO powder and the FeO generated by the oxygen blown upward to form a low-melting-point slag having a dephosphorizing ability.
When the concentration is 0.30% or less, there is a problem in that the slagging rate of the flux becomes low due to insufficient heat source. [0007] The lower the [Si] concentration in the hot metal, the higher the basicity (CaO / SiO
Since the slag of 2 ) can be formed, the amount of dephosphorized slag can be reduced. [0008] Therefore, a de-Si agent such as iron oxide is added to the hot metal discharged from the blast furnace, and the [Si] concentration in the hot metal is reduced to 0.15%.
The Si removal treatment is performed as follows. In order to enable the dephosphorization treatment even in this low Si concentration state, it is important to promote the slagging of CaO, and the establishment of the technology has been desired. SUMMARY OF THE INVENTION An object of the present invention is to reduce the [Si] concentration in hot metal to 0 . Even at a low level of 15% or less, CaO slag and FeO can be sufficiently stabilized by short-time blowing without using fluorite or the like at the time of hot metal dephosphorization. The object of the present invention is to provide a method for stably reducing the [P] concentration of the solution to 0.025% or less. Means for Solving the Problems The present inventors have obtained the following findings (A) to (C). (A) (FeO) in the dephosphorized slag is formed in the following process. Hot metal is oxidized at the fire point by top-blown oxygen,
Once FeO is generated, at this time, if there are CaO powder and Al 2 O 3 powder blown in the vicinity, they react with these and become (FeO) in the slag. However, the injected CaO powder and A
The l 2 O 3 powder is more likely to penetrate deeper than the oxygen gas reaches, and does not always coincide with the location where FeO is generated. The temperature of the ignition point generated by oxygen is estimated to be 2000 ° C. or higher, and if the generated FeO is present alone, it is very easily reduced by [C] in the hot metal as in the following formula. [C] + FeO = Fe + CO Accordingly, slight differences in operating conditions (fluctuations in lance height, fluctuations in flux addition rate, etc.) cause (Fe) in the dephosphorized slag
O) The concentration fluctuates, making it difficult to perform a stable dephosphorization treatment. (B) As a means for stabilizing the (FeO) concentration in the dephosphorized slag, a method in which a mixed flux of CaO powder and Al 2 O 3 powder and further Fe 2 O 3 powder is added to hot metal together with oxygen gas is blown upward. Is valid. (C) As a result of repeating the experiment in which Fe 2 O 3 powder was added, the (FeO) concentration in the dephosphorized slag can be stabilized at a high level, and the [P] concentration in the hot metal can be lowered to 0.025% or less. Can be stabilized. The present invention has been made on the basis of the above findings, and the gist of the present invention is that “hot metal having a [Si] concentration of 0.15% or less contained in a furnace of the top and bottom blown converter type is used. CaO powder, Al 2 O 3 powder and F from top blown oxygen lance
When a mixed powder having a particle size of 15 to 150 μm containing e 2 O 3 powder is sprayed, the mixing ratio of the Al 2 O 3 powder in the mixed powder is 3 to 20% of the CaO powder addition amount, and Fe
The mixing ratio of 2 O 3 powder is 5 to 50% of the added amount of CaO powder, and oxygen as a carrier gas is blown from the upper blowing lance at an addition rate of 0.5 to 2.0 Nm 3 / min per ton of the hot metal. The stirring gas was supplied from the furnace bottom of the top and bottom blown converter type to 0.1 tons of hot metal per ton.
A method for dephosphorizing hot metal, comprising blowing at a rate of addition of from 0.05 to 0.60 Nm 3 / min. ". DETAILED DESCRIPTION OF THE INVENTION The amount of CaO used in the present invention is 5 to 30 kg per ton of hot metal. This amount depends on the [P] concentration in the hot metal to be treated and the target after the treatment. It is determined by the [P] concentration in the hot metal and the [Si] concentration in the hot metal. The amount of Al 2 O 3 used for dephosphorizing hot metal having a [Si] concentration of 0.15% or less in the hot metal is suitably 3% to 20% of the CaO used. If the amount is less than 3%, the effect of promoting the formation of flux by the addition of Al 2 O 3 cannot be obtained. If it exceeds 20%, the activity of CaO in the slag decreases, so that the dephosphorization ability of the slag decreases. Preferably, it is 5 to 15%. In the case of dephosphorizing hot metal having a [Si] concentration of 0.15% or less in the hot metal, the amount of Fe 2 O 3 sprayed on the hot metal from the upper blowing lance is 5 to 5 times the amount of CaO used.
0% is appropriate. If it is less than 5%, (Fe) in the dephosphorized slag
O) When the concentration is T. This is because it is difficult to reach the target level of 7 to 25% in terms of Fe, and if it is added in excess of 50%, the dephosphorized slag is easily formed, slopping or the like is generated, and the operation is hindered. . CaO, Al added together with top-blown oxygen
The particle size of 2 O 3 and Fe 2 O 3 is suitably from 15 to 150 μm. The reason for this is that if it is less than 15 μm, there is a risk that the amount of scattering outside the system during the addition increases and the yield decreases.
If the thickness exceeds 0 μm, the respective reactivity may be reduced. Preferably it is 30 to 100 μm. The CaO may be quick lime conventionally used in steelmaking plants. Al 2 O 3 is bauxite is used often, it may be obtained by grinding the refractory. Fe 2 O 3 is preferably a powdery iron ore, and since it is added with an oxygen carrier, those that are easily oxidized such as scales may undesirably generate oxidative heat in the supply pipe. When the Fe 2 O 3 powder is blown upward together with oxygen, spitting tends to occur. However, in order to reduce the amount of spitting, it is preferable to place Fe 2 O 3 on the furnace in advance. At this time, the overlying Fe 2 O 3
Is not added to the mixing ratio of the mixed powder in the present invention. The amount to be placed is determined from the heat balance.
It is desirable to add at least 3 kg per hot metal ton. In order to reduce the amount of spitting, Fe 2 O
It is preferable to use one that is easy to melt as in 3 ,
What does not melt easily, such as dolomite, may be used. The amount of top blown oxygen varies depending on the target [P] concentration level and [Si] concentration level in the hot metal, but is required to be about 5 to 10 Nm 3 per ton of hot metal.
As the blowing flow rate to blow up in 10 minutes,
0.5 to 2.0 Nm 3 / min per ton of hot metal is good. As the stirring gas blown from the furnace bottom, A
One or more of r, N 2 , CO 2 , CO, O 2 , and hydrocarbons can be used. The flow rate of the hot metal is 1 to
0.05 to 0.6 Nm 3 / min per n is preferable. If the flow rate of the stirring gas is less than 0.05 Nm 3 / min, the reaction rate does not increase, and the dephosphorization reaction may not progress to the target [P] concentration level in the hot metal within the treatment time. Conversely, if it exceeds 0.6 Nm 3 / min, (FeO) in the slag is reduced by [C] in the hot metal and dephosphorization deteriorates. EXAMPLES The examples of the present invention shown in Table 1 were obtained under the following conditions.
A charge experiment was performed and evaluated. Components before hot metal treatment ([C]: about 4.5%, [Si]: 0.13 to 0.15
%, [P]: 0.10%), temperature before dephosphorization treatment 1320
250 tons of pre-siliconized hot metal at ~ 1330 ° C is poured into the top and bottom blown converter, and CO 2 is discharged from the bottom tuyere to the hot metal for 1 ton.
While blowing 0.30 Nm 3 / min per n, 7 kg / ton of iron ore was added on top. Then, using a 3-hole straight lance, with 1.0 Nm 3 / min oxygen per ton of hot metal,
CaO powder of 200 mesh under: 15kg / to
n, Al 2 O 3 powder: 1.5 kg / ton (10% of CaO powder addition amount), and Fe 2 O 3 powder: 5 kg / ton
(About 30% of the added amount of CaO powder) was sprayed onto the hot metal for 7 minutes. The hot metal temperature after treatment is
1340-1350 ° C. [Table 1] The comparative example shown in Table 2 uses the same hot metal as that of the present invention and uses the same blowing and stirring conditions, but it does not contain Fe 2 O 3 powder in the flux blown up with oxygen.
Powder: 15 kg / ton, Al 2 O 3 powder: 1.5 kg / t
Under the condition of on (10% of the added amount of CaO powder), 10 charge experiments were performed and evaluated. In order to match the total amount of Fe 2 O 3 with the case of the present invention, the amount of Fe 2 O 3 to be initially placed was 12 kg.
/ Ton. [Table 2] Comparing Table 1 with Table 2, the (T.Fe) concentration in the dephosphorized slag was more stable in the inventive example than in the comparative example, and [P] in the hot metal after the treatment was higher. The results were also stable at a low concentration. According to the present invention, [Si] concentration in hot metal
Is 0 . Even at a low level of 15% or less, sufficient slagging of CaO and FeO can be ensured by short-time blowing without using fluorite or the like at the time of hot metal dephosphorization, and a small amount of highly basic [P] 0.025% with stable concentration
Can and to Turkey below.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平11−172313（ＪＰ，Ａ) 特開 平11−241112（ＪＰ，Ａ) 特開 昭62−207810（ＪＰ，Ａ) 特開 昭57−192210（ＪＰ，Ａ) 特開 昭51−115219（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C21C 1/02 C21C 5/28 C21C 5/36 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-11-172313 (JP, A) JP-A-11-241112 (JP, A) JP-A-62-207810 (JP, A) JP-A-57-207 192210 (JP, A) JP-A-51-115219 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C21C 1/02 C21C 5/28 C21C 5/36
Claims (1)
ｉ］濃度０．１５％以下の溶銑に対し、上吹き酸素ラン
スよりＣａＯ粉、Ａｌ２ Ｏ３ 粉およびＦｅ２ Ｏ
３ 粉を含有する粒径１５〜１５０μｍの混合粉を吹き
付ける際、該混合粉のＡｌ２ Ｏ３ 粉の混合割合が、
ＣａＯ粉添加量の３〜２０％であり、かつＦｅ２ Ｏ
３ 粉混合割合がＣａＯ粉添加量の５〜５０％であり、
キャリアーガスとして酸素を該溶銑１ｔｏｎ当たり０．
５〜２．０Ｎｍ３ ／ｍｉｎの添加速度で、前記上吹き
ランスから吹き付けるとともに、前記上底吹き転炉形式
の炉底から攪拌用ガスを溶銑１ｔｏｎ当たり０．０５〜
０．６０Ｎｍ３ ／ｍｉｎの添加速度で、吹き込むこと
を特徴とする溶銑の脱りん方法。(57) [Claims] [1] [S] housed in an upper-bottom blow converter type furnace
i] CaO powder, Al 2 O 3 powder and Fe 2 O are supplied from a top-blown oxygen lance to hot metal having a concentration of 0.15% or less.
When spraying the mixed powder having a particle diameter of 15~150μm containing 3 powder, the mixing ratio of Al 2 O 3 powder of the mixed powder,
3-20% of the amount of CaO powder added, and Fe 2 O
3 powder mixing ratio is 5-50% of CaO powder addition amount,
Oxygen is used as a carrier gas in an amount of 0.1 g / ton.
At the addition rate of 5 to 2.0 Nm 3 / min, the mixture is sprayed from the upper blowing lance, and the gas for stirring is supplied from the furnace bottom of the upper and lower blowing converter type to the molten iron at a rate of 0.05 to 1 / ton.
A method for dephosphorizing hot metal, which comprises blowing at a rate of 0.60 Nm 3 / min.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30219998A JP3525766B2 (en) | 1998-10-23 | 1998-10-23 | Hot metal dephosphorization method |
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| JP3525766B2 true JP3525766B2 (en) | 2004-05-10 |
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| EP1533388B1 (en) * | 2002-08-27 | 2013-08-14 | JFE Steel Corporation | Method of manufacturing low phosphorous hot metal |
| JP4779464B2 (en) * | 2005-06-28 | 2011-09-28 | Ｊｆｅスチール株式会社 | Method for producing low phosphorus hot metal |
| JP4743078B2 (en) * | 2006-10-24 | 2011-08-10 | 住友金属工業株式会社 | Method for improving slag evacuation after dephosphorization and method for dephosphorizing hot metal using the slag |
| JP5181520B2 (en) * | 2007-04-16 | 2013-04-10 | Ｊｆｅスチール株式会社 | Hot metal dephosphorization method |
| JP5435106B2 (en) * | 2012-11-22 | 2014-03-05 | Ｊｆｅスチール株式会社 | Hot metal dephosphorization method |
| CN112964830B (en) * | 2021-02-01 | 2022-12-09 | 上海应用技术大学 | Determination of SiO in metallurgical slag 2 Activity coefficient and method of activity |
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