JP3607767B2 - Molten steel desulfurization and dehydrogenation method with small refractory melting loss - Google Patents
Molten steel desulfurization and dehydrogenation method with small refractory melting loss Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、溶鋼を同時脱硫脱水素処理する際に、取鍋・ランス・蓋等の耐火物の溶損を抑制しつつ、脱硫脱水素処理反応を効率よく行うための方法に関するものである。
【０００２】
【従来の技術】
従来、溶鋼の脱硫及び脱水素処理を同時に行う方法として、特開昭５８−２２３１９、特開昭５８−２２３２０に示す様な、真空脱ガス槽とフラックスインジェクションを組み合わせ、真空脱ガス槽内を減圧し真空下で脱硫剤を不活性ガス等のキャリヤーガスと共に吹込み、脱硫、脱水素方法を実施していた。
【０００３】
【発明が解決しようとする課題】
しかるに上記方法は以下の様な欠点を有する。上記方法は、減圧下でインジェクションを行う強撹拌（図１）プロセスであり、精錬特性は非常に良好であるが、使用するランス・蓋・取鍋耐火物の溶損が激しく、耐火物コストが処理コストを逼迫していた。
【０００４】
また、脱硫剤を不活性ガス等のキャリヤーガスと共に吹込み脱硫処理を行っていたため、処理中に脱硫剤中の水分として水素を供給することとなり、見かけの脱水速度が小さくなり、脱水素のための処理時間が長くなっていた。このことが更に耐火物の溶損を大きくしていた（図２，３）。
【０００５】
本発明は前記従来技術の問題点を解消するために、
▲１▼脱硫反応に支障のない、且つ、耐火物溶損の少ないスラグ組成領域を提供し、
▲２▼特に、要求製品［Ｓ］の厳しくないものについては、使用するフラックスを脱硫処理前に取鍋に投入しておくことで脱水素処理時間を短くし、且つ、不活性ガスのみの撹拌により撹拌力を抑制した最適撹拌力の脱硫脱水素処理方法を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
本発明は上記した問題点を解決するために、脱硫剤の脱硫能力・減圧という脱水素能力を最大限経済的にかつ効率的に活用し、また、耐火物の溶損を最低限に抑制するためのものである。
【０００７】
本願発明の要するところは、
（１）溶鋼を減圧下で精練する際、ＣａＯ−Ａｌ２ Ｏ３ −ＳｉＯ２ −ＭｇＯ−ＣａＦ２ 五元系を主成分とし、下記のようなスラグ組成で脱硫脱水素処理を行う事を特徴とする耐火物溶損の小さい溶鋼脱硫脱水素方法
（％ＭｇＯ）＝５〜１５％，
（％ＣａＦ２ ）≦１０％，
（％ＣａＯ）／（％ＳｉＯ２ ）≧３，
１≦（％ＣａＯ）／（Ａｌ２ Ｏ３ ）≦３
（２）（１）記載の溶鋼の脱硫脱水素方法において、スラグ成分を調整するためのスラグ成分調整用フラックスあるいは精錬用フラックスを、溶鋼の脱硫脱水素処理を行う前までに取鍋内へ添加して、減圧下で不活性ガスで撹拌を行う事を特徴とする耐火物溶損の小さい脱硫脱水素方法。
である。
【０００８】
【発明の実施の形態】
以下、本願発明を採用した操業について２つのケースについて詳細に説明する。
【０００９】
（１）まず、要求製品［Ｓ］の厳しい鋼種製造の場合は、
転炉吹錬終了前に、マスバランス計算により転炉スラグの組成を求め、出鋼時の取鍋への流出量を仮定する。また、脱硫処理終了後の脱硫反応平衡計算から取鍋内に必要なスラグボリウムを算出する。この二つの計算を元に、（％ＭｇＯ）＝５〜１５％，（％ＣａＦ２ ）≦１０％，（％ＣａＯ）／（％ＳｉＯ２ ）≧３，１≦（％ＣａＯ）／（Ａｌ２ Ｏ３ ）≦３であるスラグ組成となるようにマスバランス計算を行い、使用すべき脱硫剤及びスラグ成分調整用フラックス等の量を算出する。
【００１０】
併せて、脱水素反応速度から求まる脱水素処理時間（減圧処理時間）から、その範囲内で吹き込み可能な脱硫剤量を算定し、それ以外の必要脱硫剤及びスラグ成分調整用フラックス等は転炉出鋼前から脱硫処理開始前までに取鍋内に投入しておく。
【００１１】
ここで、ＭｇＯ源としては、生ドロマイト、軽焼ドロマイト、ＭｇＯ系レンガ屑、ＭｇＯ系耐火物屑、Ｍｇ等を使用する。Ａｌ２ Ｏ３ 源として、Ａｌ灰、Ａｌ滓、Ａｌ２ Ｏ３ 系レンガ屑、Ａｌ２ Ｏ３ 系耐火物屑、Ａｌ等を使用する。ＣａＯ源として、生石灰、石灰石、炭酸カルシウム、炭化カルシウム等を使用する。Ｆ源として、蛍石を用い、脱硫剤は、ＣａＯ単独、ＣａＯ−ＣａＦ２ ，ＣａＯ−Ａｌ２ Ｏ３ 源、ＣａＯ−ＭｇＯ源及びこれらを組み合わせたものを使用する。
【００１２】
次に、真空脱ガス槽内減圧開始と共に脱硫剤を不活性ガス等のキャリヤーガスと共に吹込み、脱水素を終了する（排気終了）と同時に脱硫剤の添加を停止し、処理を終了する。復圧したのちＣａ成分を添加し、極低硫、極清浄鋼（低酸素、低水素、Ｃａ添加）を歩留良く製造する。
【００１３】
（２）また、要求製品［Ｓ］がそれほど厳しくない鋼種製造の場合は、
上記（１）と同様にマスバランス計算により使用すべき脱硫剤及びスラグ成分調整用フラックス等の量を算出し、全必要脱硫剤及びスラグ成分調整用フラックスを転炉出鋼前から脱硫処理開始前までに取鍋内に投入し、真空脱ガス槽内減圧開始と共に不活性ガス等のガスをインジェクションあるいはバブリングにより溶鋼を撹拌し、吹込脱水素処理を行う。脱水素終了する（排気終了）と同時に処理を完了する。
【００１４】
上記（１），（２）には次の様な特徴がある。
（１）のケースは、撹拌力が非常に大きい。減圧下でガスを吹き込むため、溶鋼中で膨張し溶鋼を撹拌する。粉体を搬送するため、ガス流量が多く、吹き込む粉体の運動エネルギーがそのまま溶鋼撹拌エネルギーとなる。しかし、処理中に脱硫剤を不活性ガス等のキャリヤーガスと共に吹き込むため脱硫剤中の水分として水素を供給することとなり、脱硫同時脱水素処理時間が長くなる。
【００１５】
この処理方法を適用するのは、脱水素処理より脱硫処理がネックとなる［Ｓ］の要求が厳しい鋼種の時に採用する。
【００１６】
（２）のケースは、（１）と比較すると、撹拌力が小さい。上記（１）よりガス流量が少なく、吹き込む粉体がないため撹拌力が小さい。しかし、処理中に吹き込む脱硫剤がなく、処理中の水素源の供給がなく、効率的な脱水素処理が可能である。
【００１７】
この処理方法を適用するのは、脱硫処理より脱水素処理がネックとなる鋼種の時に採用する。
【００１８】
いずれの場合も、スラグ組成を本願発明方法に示した組成に調整することにより取鍋などの耐火物溶損は、従来よりも大幅に低減できる。
【００１９】
【作用】
次に、本願発明の数値限定の理由について説明する。
【００２０】
（１）本願発明は、減圧下での溶鋼脱硫脱水素処理を前提としており、これは脱硫処理と同時に脱水素処理を行うためであり、また、同じガス流量のインジェクションあるいは、バブリングでも大気圧下の処理に比較して大きな撹拌を得るためである（図１）。
【００２１】
（２）次に、スラグ成分の限定根拠について述べる。ＭｇＯは、耐火物溶損抑制目的に添加するものであり、その溶損抑制効果は５％以上で発揮し、また、１５％超では、スラグの融点が高くなり、スラグの流動性が悪化し、スラグ−メタル反応に支障を来すので、（％ＭｇＯ）＝５〜１５％とした（図４）。
【００２２】
（３）ＣａＦ２ はスラグの融点を下げ、スラグ−メタル反応性を高め、脱硫能力を向上させるために有効であるため添加するものである。しかし、１０％以上添加すると、融点が低下しすぎ、耐火物の溶損を大きくするので上限を１０％とした。
【００２３】
（４）また、高脱硫能を保持するために、（％ＣａＯ）／（％ＳｉＯ２ ）≧３とする。
【００２４】
（５）Ａｌ２ Ｏ３ は、耐火物溶損抑制、鋼脱硫能を得るために添加するものである。しかし、（％ＣａＯ）／（Ａｌ２ Ｏ３ ）≦１まで添加すると、逆に脱硫能が低下するので下限を１とした。また、図５でも示したように（％ＣａＯ）／（Ａｌ２ Ｏ３ ）≧３では耐火物の溶損量が大きいため、上限を３とする。
【００２５】
（６）次に、要求製品［Ｓ］がそれほど厳しくなく、あるいは、要求製品［Ｈ］が厳しい場合、スラグ成分調整用のフラックス、あるいは、脱硫用フラックスを溶鋼処理前に添加する。このことによって、フラックスからの供給［Ｈ］源が処理前に一括してインプットされるので、フラックスを処理中インジェクションする場合よりも脱水素のための処理時間が短時間で済み、且つ、撹拌力もフラックスインジェクションよりも抑制する事ができ、必要最小限の撹拌力と撹拌時間で処理可能となり、耐火物の溶損抑制に寄与する。
【００２６】
【実施例】
実施例
表１に本発明の実施例及び比較例を示す。
実施例における本発明法では、ＣａＯ源として生石灰、Ａｌ２ Ｏ３ 源としてＡｌ灰、ＭｇＯ源としてレンガ屑を使用している。従来法では、生石灰と蛍石のみ使用している。
【００２７】
本発明法では、いずれの場合も取鍋脱硫を行う前に、スラグ組成を請求範囲に示すように（％ＭｇＯ）＝５〜１５％，（％ＣａＦ２ ）≦１０％，（％ＣａＯ）／（％ＳｉＯ２ ）≧３，１≦（％ＣａＯ）／（Ａｌ２ Ｏ３ ）＜３のスラグ組成に調整を行う。
【００２８】
従来法では、転炉から流出したスラグに精錬用のＣａＯ，ＣａＦ２ を少量添加するのみであった。従って、表に示すように（％Ａｌ２ Ｏ３ ）と（％ＭｇＯ）が小さく（％ＣａＯ）／（％Ａｌ２ Ｏ３ ）が大きな値であることが分かる。
【００２９】
取鍋脱硫処理の方法として、従来法ではＣ：不活性ガス搬送粉体インジェクションを採用していたが、本発明法では比較的撹拌力の弱いＡ：不活性ガス鍋底バブリング、Ｂ：不活性ガスインジェクションを用い、脱硫処理がネックとなる場合Ｃ法を採用する。
【００３０】
従来法では、脱硫・脱水素の処理時間で約１６〜１８分程度かかっていたが、Ａ法では１５分、Ｂ法では１２〜１３分程で処理が完了する。本発明法におけるＣ法では最短の１０分程度で処理は完了する。
【００３１】
耐火物からのＡｌ２ Ｏ３ ，ＭｇＯ溶出量についてみる。従来法ではＡｌ２ Ｏ３ が１０００ｋｇ近く、ＭｇＯが３５０ｋｇ程度溶出していたものが、本発明法では表で示すように、少量の溶出量に抑えることができる。
【００３２】
【表１】
【発明の効果】
本願発明の効果として、従来、取鍋の溶損を抑えるためにレンガ鍋とし、高コストとなっていたものを、従来、溶損が大きく、適用不可能とされていた一般に適用されている不定形の鍋に変更することができ、鍋耐火物の大幅なコスト削減が達成できた。また、その他の蓋やランス耐火物においても溶損が抑制され、処理コスト削減に大きく寄与した。
【図面の簡単な説明】
【図１】真空度と撹拌エネルギーとの関係を示す図。
【図２】処理時間に対する耐火物からのＡｌ２ Ｏ３ 溶出量を示す図。
【図３】処理時間に対する耐火物からのＭｇＯ溶出量を示す図。
【図４】処理開始時スラグの（％ＭｇＯ）に対するＭｇＯ溶出量を示す図。
【図５】処理開始時スラグの（ＣａＯ）／（Ａｌ２ Ｏ３ ）に対するＡｌ２ Ｏ３ 溶出量を示す図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for efficiently performing a desulfurization dehydrogenation treatment reaction while suppressing melting damage of refractories such as a ladle, a lance, and a lid when simultaneous desulfurization dehydrogenation treatment of molten steel is performed.
[0002]
[Prior art]
Conventionally, as a method for simultaneously performing desulfurization and dehydrogenation treatment of molten steel, a vacuum degassing tank and a flux injection as shown in JP-A-58-22319 and JP-A-58-22320 are combined to reduce the pressure in the vacuum degassing tank. However, a desulfurization agent was blown together with a carrier gas such as an inert gas under vacuum to carry out a desulfurization and dehydrogenation method.
[0003]
[Problems to be solved by the invention]
However, the above method has the following drawbacks. The above method is a strong agitation process (Fig. 1) in which injection is performed under reduced pressure, and the refining characteristics are very good, but the lance, lid, and ladle refractories used are severely damaged and the refractory costs are low. Processing costs were tight.
[0004]
In addition, since the desulfurization treatment was performed by blowing the desulfurization agent together with a carrier gas such as an inert gas, hydrogen was supplied as moisture in the desulfurization agent during the treatment, so that the apparent dehydration rate was reduced and dehydrogenation was performed. The processing time of was long. This further increased the melting loss of the refractory (FIGS. 2 and 3).
[0005]
The present invention solves the problems of the prior art,
(1) Providing a slag composition region that does not interfere with the desulfurization reaction and has little refractory erosion loss,
(2) Especially for the less demanding products [S], the dehydrogenation time can be shortened by adding the flux to be used to the ladle before the desulfurization treatment, and only the inert gas is stirred. It aims at providing the desulfurization dehydrogenation processing method of the optimal stirring power which suppressed stirring power by.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention utilizes the desulfurization ability of the desulfurization agent such as desulfurization ability / decompression to the maximum economically and efficiently, and suppresses the refractory melting to a minimum. Is for.
[0007]
The point of the present invention is that
(1) When smelting molten steel under reduced pressure, it is characterized by a desulfurization and dehydrogenation treatment with a slag composition as described below, mainly composed of a ternary system of CaO—Al 2 O 3 —SiO 2 —MgO—CaF 2. The molten steel desulfurization dehydrogenation method (% MgO) = 5-15% with a small refractory melting loss
(% CaF 2 ) ≦ 10%,
(% CaO) / (% SiO 2 ) ≧ 3
1 ≦ (% CaO) / (Al 2 O 3 ) ≦ 3
(2) In the desulfurization dehydrogenation method for molten steel described in (1), the slag component adjustment flux or refining flux for adjusting the slag component is added to the ladle before the desulfurization dehydrogenation treatment of the molten steel. Then, a desulfurization dehydrogenation method having a small refractory refractory loss characterized by stirring with an inert gas under reduced pressure.
It is.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, two cases of operations employing the present invention will be described in detail.
[0009]
(1) First, in the case of strict steel grade production of the required product [S],
Before the end of converter blowing, the composition of converter slag is obtained by mass balance calculation, and the outflow to the ladle at the time of steel output is assumed. Moreover, the slag volume required in the ladle is calculated from the desulfurization reaction equilibrium calculation after the desulfurization treatment is completed. Based on these two calculations, (% MgO) = 5-15%, (% CaF 2 ) ≦ 10%, (% CaO) / (% SiO 2 ) ≧ 3, 1 ≦ (% CaO) / (Al 2 Mass balance calculation is performed so that the slag composition satisfies O 3 ) ≦ 3, and the amounts of desulfurizing agent and slag component adjusting flux to be used are calculated.
[0010]
In addition, the amount of desulfurization agent that can be blown in within the range is calculated from the dehydrogenation treatment time (decompression treatment time) obtained from the dehydrogenation reaction rate, and other necessary desulfurization agent and slag component adjustment flux, etc. It is put into the ladle before the steel is discharged and before the desulfurization treatment is started.
[0011]
Here, as the MgO source, raw dolomite, light-burned dolomite, MgO-based brick waste, MgO-based refractory waste, Mg, or the like is used. As the Al 2 O 3 source, Al ash, Al soot, Al 2 O 3 -based brick scrap, Al 2 O 3 -based refractory scrap, Al or the like is used. As the CaO source, quick lime, limestone, calcium carbonate, calcium carbide and the like are used. As the F source, fluorite is used, and as the desulfurizing agent, CaO alone, CaO—CaF 2 , CaO—Al 2 O 3 source, CaO—MgO source, and combinations thereof are used.
[0012]
Next, the desulfurization agent is blown together with a carrier gas such as an inert gas at the same time as the depressurization in the vacuum degassing tank is started, the dehydrogenation is finished (exhaust is finished), and at the same time, the addition of the desulfurization agent is stopped and the process is finished. After returning to pressure, the Ca component is added to produce ultra-low sulfur and ultra-clean steel (low oxygen, low hydrogen, Ca addition) with good yield.
[0013]
(2) In addition, in the case of steel grade production where the required product [S] is not so strict,
As in (1) above, calculate the amount of desulfurization agent and slag component adjustment flux to be used by mass balance calculation, and add all necessary desulfurization agent and slag component adjustment flux from the converter steel before the desulfurization treatment starts. It is put into the ladle by the beginning, and the molten steel is stirred by injection or bubbling with a gas such as an inert gas at the same time as the pressure reduction in the vacuum degassing tank is started, and the blowing dehydrogenation treatment is performed. The process is completed simultaneously with the end of dehydrogenation (end of exhaust).
[0014]
The above (1) and (2) have the following characteristics.
In the case (1), the stirring force is very large. In order to blow gas under reduced pressure, it expands in the molten steel and stirs the molten steel. Since the powder is conveyed, the gas flow rate is large, and the kinetic energy of the blown powder becomes the molten steel stirring energy as it is. However, since the desulfurization agent is blown together with a carrier gas such as an inert gas during the treatment, hydrogen is supplied as moisture in the desulfurization agent, and the desulfurization simultaneous dehydrogenation treatment time becomes longer.
[0015]
This treatment method is applied when the steel type is more demanding of [S], where desulfurization is a bottleneck than dehydrogenation.
[0016]
In the case of (2), the stirring force is small compared to (1). The gas flow rate is smaller than in (1) above, and the stirring force is small because there is no powder to be blown. However, there is no desulfurizing agent to be blown during the treatment, no supply of a hydrogen source during the treatment, and an efficient dehydrogenation treatment is possible.
[0017]
This treatment method is applied when the steel grade is dehydrogenation rather than desulfurization.
[0018]
In any case, the refractory melting loss of the ladle or the like can be significantly reduced by adjusting the slag composition to the composition shown in the method of the present invention.
[0019]
[Action]
Next, the reason for the numerical limitation of the present invention will be described.
[0020]
(1) The present invention is premised on desulfurization and desulfurization of molten steel under reduced pressure. This is because dehydrogenation is performed simultaneously with desulfurization, and even under injection or bubbling at the same gas flow rate under atmospheric pressure. This is because a large agitation is obtained as compared with the above process (FIG. 1).
[0021]
(2) Next, the grounds for limiting the slag component will be described. MgO is intended to be added to the refractory erosion suppression purposes, exert its corrosion inhibiting effect is 5% or more, and, in 15%, greater than the melting point of the slag is increased, the fluidity of the slag is deteriorated Since it interferes with the slag-metal reaction, (% MgO) was set to 5 to 15% (FIG. 4).
[0022]
(3) CaF 2 is added because it is effective for lowering the melting point of slag, increasing slag-metal reactivity, and improving desulfurization capacity. However, if added at 10% or more, the melting point is too low and the melting loss of the refractory is increased, so the upper limit was made 10%.
[0023]
(4) In order to maintain high desulfurization ability, (% CaO) / (% SiO 2 ) ≧ 3.
[0024]
(5) Al 2 O 3 is added in order to obtain refractory material melting loss suppression and steel desulfurization ability. However, if (% CaO) / (Al 2 O 3 ) ≦ 1 is added, the desulfurization ability decreases, so the lower limit is set to 1. Also, as shown in FIG. 5, when (% CaO) / (Al 2 O 3 ) ≧ 3, the amount of refractory melt is large, so the upper limit is set to 3.
[0025]
(6) Next, when the required product [S] is not so strict or the required product [H] is strict, a flux for adjusting a slag component or a flux for desulfurization is added before the molten steel treatment. As a result, the supply [H] source from the flux is input all at once before the treatment, so that the treatment time for dehydrogenation is shorter than the case of injecting the flux during the treatment, and the stirring power is also increased. It can be controlled more than flux injection, and can be processed with the minimum necessary stirring force and stirring time, contributing to the suppression of refractory melting.
[0026]
【Example】
Examples Table 1 shows examples of the present invention and comparative examples.
In the method of the present invention in Examples, quick lime is used as the CaO source, Al ash is used as the Al 2 O 3 source, and brick scrap is used as the MgO source. In the conventional method, only quicklime and fluorite are used.
[0027]
In the method of the present invention, before performing ladle desulfurization in any case, as shown in the claims, (% MgO) = 5-15%, (% CaF 2 ) ≦ 10%, (% CaO) / Adjustment is made to a slag composition of (% SiO 2 ) ≧ 3, 1 ≦ (% CaO) / (Al 2 O 3 ) <3.
[0028]
In the conventional method, only a small amount of refining CaO, CaF 2 is added to the slag flowing out of the converter. Therefore, as shown in the table, (% Al 2 O 3 ) and (% MgO) are small and (% CaO) / (% Al 2 O 3 ) is a large value.
[0029]
As a ladle desulfurization treatment method, C: inert gas conveying powder injection was adopted in the conventional method, but in the method of the present invention, A: inert gas pan bottom bubbling, B: inert gas, which has a relatively weak stirring force. When injection is used and desulfurization treatment becomes a bottleneck, the C method is adopted.
[0030]
In the conventional method, the processing time of desulfurization / dehydrogenation takes about 16 to 18 minutes, but the processing is completed in 15 minutes in the method A and 12 to 13 minutes in the method B. In the method C according to the present invention, the processing is completed in a minimum of about 10 minutes.
[0031]
Let us examine the elution amount of Al 2 O 3 and MgO from refractories. In the conventional method, Al 2 O 3 was eluted at about 1000 kg and MgO was eluted at about 350 kg, but in the method of the present invention, as shown in the table, it can be suppressed to a small amount.
[0032]
[Table 1]
【The invention's effect】
As an effect of the present invention, conventionally, a brick pan is used in order to suppress melting damage of the ladle, and what has become a high cost is a generally applied failure that has been previously considered to be unusable due to large melting damage. It was possible to change to a regular pan, and a significant cost reduction of pan refractories was achieved. In addition, melting loss was suppressed in other lids and lance refractories, which greatly contributed to processing cost reduction.
[Brief description of the drawings]
FIG. 1 is a diagram showing a relationship between a degree of vacuum and stirring energy.
FIG. 2 is a graph showing the amount of Al 2 O 3 eluted from the refractory with respect to the treatment time.
FIG. 3 is a view showing an elution amount of MgO from a refractory with respect to a treatment time.
FIG. 4 is a graph showing the MgO elution amount with respect to (% MgO) of slag at the start of treatment.
FIG. 5 is a graph showing the amount of Al 2 O 3 eluted with respect to (CaO) / (Al 2 O 3 ) of slag at the start of treatment.
Claims (2)
（％ＭｇＯ）＝５〜１５％，
（％ＣａＦ２ ）≦１０％，
（％ＣａＯ）／（％ＳｉＯ２ ）≧３，
１≦（％ＣａＯ）／（Ａｌ２ Ｏ３ ）≦３When refining molten steel under vacuum, mainly composed of CaO-Al 2 O 3 -SiO 2 -MgO-CaF 2 quinary system, characterized in that performing at slag composition desulfurization dehydrogenation as follows refractory Molten steel desulfurization dehydrogenation method (% MgO) = 5-15% with low material damage
(% CaF 2 ) ≦ 10%,
(% CaO) / (% SiO 2 ) ≧ 3
1 ≦ (% CaO) / (Al 2 O 3 ) ≦ 3
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| JP31653295A JP3607767B2 (en) | 1995-12-05 | 1995-12-05 | Molten steel desulfurization and dehydrogenation method with small refractory melting loss |
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| JP31653295A JP3607767B2 (en) | 1995-12-05 | 1995-12-05 | Molten steel desulfurization and dehydrogenation method with small refractory melting loss |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2000017320A (en) * | 1998-07-03 | 2000-01-18 | Kawasaki Steel Corp | Method for preventing erosion of lining brick in ladle |
| JP2000212633A (en) * | 1999-01-28 | 2000-08-02 | Kawasaki Steel Corp | Desulfurization of molten steel in ladle refining |
| JP3726599B2 (en) * | 1999-11-24 | 2005-12-14 | Ｊｆｅスチール株式会社 | Method for refining molten steel using refractory scrap containing carbon |
| JP2001164313A (en) * | 1999-12-09 | 2001-06-19 | Kyoei Steel Ltd | Method for reforming slag in ladle refining furnace |
| JP4499969B2 (en) * | 2001-11-15 | 2010-07-14 | Ｊｆｅスチール株式会社 | Desulfurization method by ladle refining of molten steel |
| JP4184884B2 (en) * | 2003-07-24 | 2008-11-19 | 大同エコメット株式会社 | Steelmaking material for desulfurization and refining of steel |
| JP5008296B2 (en) * | 2005-10-19 | 2012-08-22 | 新日鐵住金ステンレス株式会社 | Hydraulic composition and hydrated solidified body |
| JP4609325B2 (en) * | 2006-01-11 | 2011-01-12 | 住友金属工業株式会社 | Treatment method of molten iron by Nd addition |
| KR100768323B1 (en) * | 2006-06-30 | 2007-10-18 | 주식회사 포스코 | Method for controlling hydrogen in liquid mg alloys |
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