JP2020139219A - Upper blowing lance and refining method of molten iron - Google Patents

Upper blowing lance and refining method of molten iron Download PDF

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JP2020139219A
JP2020139219A JP2019037794A JP2019037794A JP2020139219A JP 2020139219 A JP2020139219 A JP 2020139219A JP 2019037794 A JP2019037794 A JP 2019037794A JP 2019037794 A JP2019037794 A JP 2019037794A JP 2020139219 A JP2020139219 A JP 2020139219A
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blowing
control gas
opening
lance
oxygen
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JP7003947B2 (en
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新司 小関
Shinji Koseki
新司 小関
新吾 佐藤
Shingo Sato
新吾 佐藤
典子 小澤
Noriko Ozawa
典子 小澤
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JFE Steel Corp
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JFE Steel Corp
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Abstract

To provide an upper blowing lance for blowing an oxygen-containing gas onto molten iron charged into a reaction vessel to perform acid refining on the molten iron, and to propose a method for refining molten iron using the upper blowing lance.SOLUTION: An upper blowing lance includes: one or more main blowing openings for ejecting oxygen-containing gas through an outer shell of the upper blowing lance; a control gas supply path having an opening arranged on an inner wall surface of the main blowing openings for ejecting control gas toward a center axis of the main blowing openings; main oxygen supply means for supplying the oxygen-containing gas from the inlet of the main blowing openings; and control gas supply means for supplying the control gas to the control gas supply path. The upper blowing lance has a throttle at the vicinity of the opening of the control gas supply path. A method for refining molten iron, in which a ratio of the control gas is determined by using the upper blowing lance, is proposed.SELECTED DRAWING: Figure 3

Description

本発明は、反応容器に装入した溶鉄に酸素含有ガスを吹き付けて溶鉄に送酸精錬を施すための上吹きランスおよびその上吹きランスを用いた溶鉄の精錬方法に関する。 The present invention relates to a top-blown lance for spraying oxygen-containing gas onto molten iron charged in a reaction vessel to perform acid-feeding refining of the molten iron, and a method for refining molten iron using the top-blown lance.

溶鉄の酸化精錬において、反応効率向上の観点から、上吹きランスから噴射される酸素含有ガスの溶鉄浴面での噴流流速とガス流量とを同時に制御できる実用的な送酸手段が求められている。 In the oxidation refining of molten iron, from the viewpoint of improving the reaction efficiency, a practical acid feeding means capable of simultaneously controlling the jet flow velocity and the gas flow rate of the oxygen-containing gas injected from the top-blown lance on the molten iron bath surface is required. ..

例えば、鉄鋼精錬における製鋼プロセスでは、溶鋼への酸素上吹きによる脱炭処理が行われる。この脱炭処理は精錬中の溶鋼の成分変化によって初期、最盛期、末期と分けられる。 For example, in the steelmaking process in steel refining, decarburization treatment is performed by blowing oxygen over the molten steel. This decarburization process is divided into the initial stage, the peak stage, and the final stage according to the change in the composition of the molten steel during refining.

脱炭最盛期では炭素濃度が高い状態であることから、上吹き酸素噴流が溶鋼界面に衝突した際に炭素と反応しやすいため、酸素流量を増やせば増やすほど脱炭速度が上昇する酸素供給律速である。そのため、脱炭最盛期では精錬の処理時間を短縮するために、可能な限り酸素流量を増やすべきであるが、酸素流量を増加させると、溶湯面での噴流の流速が高くなるとともに浴面動圧が上昇するために、ダストなどとして炉外に飛散する鉄分が増加したり、溶鋼やスラグをはねあげるスプラッシュが増大し炉壁や炉口付近に付着・堆積したりことになる。この量が多くなると、鉄歩留低下によるコストの増加を招き、スプラッシュがランスや転炉内壁に大量に付着すると、地金を除去する作業が発生するため、操業を阻害してしまう。つまり、酸素流量の増加と、ダスト量およびスプラッシュ量はトレードオフの関係にある。つまり脱炭最盛期においては、酸素流量を増加しても湯面流速(動圧)が上昇しないような操業が望ましいといえる。 Since the carbon concentration is high at the peak of decarburization, it easily reacts with carbon when the top-blown oxygen jet collides with the molten steel interface. Therefore, the decarburization rate increases as the oxygen flow rate increases. Is. Therefore, in the peak decarburization period, the oxygen flow rate should be increased as much as possible in order to shorten the refining processing time. However, when the oxygen flow rate is increased, the flow velocity of the jet flow on the molten metal surface increases and the bath surface moves. As the pressure rises, the amount of iron scattered outside the furnace as dust increases, and the amount of splash that splashes molten steel and slag increases, causing it to adhere and accumulate near the furnace wall and furnace opening. If this amount is large, the cost will increase due to the decrease in iron yield, and if a large amount of splash adheres to the lance or the inner wall of the converter, the work of removing the bare metal will occur, which will hinder the operation. That is, there is a trade-off relationship between the increase in oxygen flow rate and the amount of dust and splash. In other words, in the peak period of decarburization, it is desirable to operate so that the flow velocity (dynamic pressure) on the molten metal does not increase even if the oxygen flow rate is increased.

一方で、脱炭末期には炭素濃度がある程度低下しており、上吹き酸素が火点で炭素と結びつく確率が低下するため、上吹き酸素量を増加しても脱炭速度が上昇しにくい。酸素を増加した場合は、炭素の代わりに鉄が酸素と結びつき、酸化鉄が生成しやすくなる。酸化鉄は溶鋼中の炭素と反応して脱炭反応を生じる物質であるが、単に浴面近傍に蓄積するだけでは脱炭に寄与しないため、溶鋼を撹拌して酸化鉄と溶鋼中の炭素が反応する確率を上げる必要がある。すなわち、脱炭末期においては、酸化鉄の生成量が増えすぎないようにした上で、溶湯の撹拌力を強化するような操業が求められる。そのための対策として、脱炭末期においては、流量を増加することなく上吹きガスの流速を上昇させて撹拌を強化するような操業が望ましい。 On the other hand, at the end of decarburization, the carbon concentration decreases to some extent, and the probability that top-blown oxygen binds to carbon at the fire point decreases. Therefore, even if the amount of top-blown oxygen is increased, the decarburization rate does not easily increase. When oxygen is increased, iron is combined with oxygen instead of carbon, and iron oxide is easily produced. Iron oxide is a substance that reacts with carbon in molten steel to cause a decarburization reaction, but simply accumulating near the bath surface does not contribute to decarburization. Therefore, iron oxide and carbon in molten steel are agitated by stirring the molten steel. It is necessary to increase the probability of reaction. That is, at the final stage of decarburization, an operation is required in which the agitation power of the molten metal is strengthened while preventing the amount of iron oxide produced from increasing too much. As a countermeasure for this, at the end of decarburization, it is desirable to operate by increasing the flow velocity of the top-blown gas without increasing the flow rate to strengthen the agitation.

一般に、酸素流量の調整とは独立して浴面での流速を調整する方法として、ランス高さを調整する方法が用いられている。しかし、ランス高さを低くし過ぎると、飛散した溶鉄による溶損を受けてランス寿命が著しく低下する問題があり、また、ランス高さを高くし過ぎると、2次燃焼率の増大や2次燃焼着熱効率の低下によって炉内ガス温度が上昇し、耐火物寿命の低下を招く問題があるため、ランス高さによる流速の調整範囲には限界がある。このため、酸素流量に拠らずに噴射速度を調整可能な上吹きランスの実現が期待されていた。 Generally, a method of adjusting the lance height is used as a method of adjusting the flow velocity on the bath surface independently of the adjustment of the oxygen flow rate. However, if the lance height is too low, there is a problem that the lance life is significantly shortened due to melting damage due to scattered molten iron, and if the lance height is too high, the secondary combustion rate increases and the secondary combustion rate increases. Since there is a problem that the gas temperature in the furnace rises due to the decrease in combustion thermal efficiency and the life of the refractory is shortened, there is a limit to the range of adjusting the flow velocity by the lance height. Therefore, it has been expected to realize a top-blowing lance that can adjust the injection speed regardless of the oxygen flow rate.

また、製鋼工程では、転炉での製鋼スラグ発生量の低減や製鋼トータルコストの削減を図るために、転炉で脱炭吹錬する前に、溶銑中に含有するSiやPを予め酸化剤を用いて除去する方法がとられているが、その方法のひとつに、処理容器として転炉を用いた脱りん吹錬がある。 Further, in the steelmaking process, in order to reduce the amount of steelmaking slag generated in the converter and the total cost of steelmaking, Si and P contained in the hot metal are preliminarily used as an oxidizing agent before decarburization and blowing in the converter. One of the methods is dephosphorization using a converter as a processing container.

この転炉を用いた脱りん吹錬は、一般的には、脱炭吹錬と同様に、溶銑の湯面上方から上吹きランスを用いて酸素含有ガスを吹きつけながら、石灰等の精錬剤(以下、フラックスと称する)を溶銑に添加するものである。このときも、上吹きランスから供給される酸素含有ガス噴流の流速を調節することによって、脱りん吹錬時に生成するスラグ中のT.Fe濃度(トータル鉄分濃度)を制御する手法がとられる。 In general, the dephosphorization smelting using this converter is similar to the decarburization smelting, in which an oxygen-containing gas is blown from above the surface of the hot metal by using a top lance to smelt a lime or the like. (Hereinafter referred to as flux) is added to the hot metal. Also at this time, by adjusting the flow velocity of the oxygen-containing gas jet supplied from the top-blowing lance, the T.I. A method of controlling the Fe concentration (total iron concentration) is adopted.

たとえば、脱炭の最盛期と末期では、求められる操業条件が異なるため、上吹きランスは脱炭最盛期では流速増加を抑えられるストレートノズルを使用し、脱炭末期では流速上昇が可能なラバールノズルを使用するべきである。しかし、精錬中にランスの取り換えを行うことは困難であるために、一本のランスで操業を行う必要がある。吹錬中にノズル形状を制御する技術としては、例えば、特許文献1には、機械的にノズル形状を変える真空脱ガス槽内の上吹きランスの技術が開示されている。 For example, since the required operating conditions are different between the peak and end of decarburization, the top blow lance uses a straight nozzle that can suppress the increase in flow velocity at the peak of decarburization, and a Laval nozzle that can increase the flow velocity at the end of decarburization. Should be used. However, since it is difficult to replace the lance during refining, it is necessary to operate with a single lance. As a technique for controlling the nozzle shape during blowing, for example, Patent Document 1 discloses a technique for a top blowing lance in a vacuum degassing tank that mechanically changes the nozzle shape.

また、噴流制御のひとつにランスノズルの主噴流とは別の制御流の利用があげられる。例えば特許文献2には、流体噴出流路の側壁に制御ガス用の一対の開口部を設け、噴流方向を制御する方法が開示されている。また、特許文献3には、上吹きランスのラバールノズルに別のラバールノズルを延長するように重ねることによって、噴流流速を変える技術が開示されている。 In addition, one of the jet controls is the use of a control flow different from the main jet of the lance nozzle. For example, Patent Document 2 discloses a method of controlling the jet direction by providing a pair of openings for control gas on the side wall of the fluid jet flow path. Further, Patent Document 3 discloses a technique of changing the jet flow velocity by superimposing another Laval nozzle on the Laval nozzle of the top blowing lance so as to extend.

特開平8−260029号公報Japanese Unexamined Patent Publication No. 8-260029 特開2005−113200号公報Japanese Unexamined Patent Publication No. 2005-113200 特開2000−234115号公報Japanese Unexamined Patent Publication No. 2000-234115

しかしながら、機械的にノズル形状を変える方法である特許文献1に開示の方法は、高温かつダストが発生する雰囲気下で機械的可動部を持つなどの点で実用的でない上、噴出孔が多数あるランスへの応用が困難という問題があった。また、ノズル内面の可動部によって断面積を縮小する場合、この段差部分において段差が生じるが、この段差の形状がガス流速に及ぼす影響も必ずしも明らかではなかった。 However, the method disclosed in Patent Document 1, which is a method of mechanically changing the nozzle shape, is not practical in that it has a mechanically movable part in an atmosphere where high temperature and dust are generated, and there are many ejection holes. There was a problem that it was difficult to apply it to lances. Further, when the cross-sectional area is reduced by the movable portion on the inner surface of the nozzle, a step is generated at this step portion, but the influence of the shape of this step on the gas flow velocity is not always clear.

また、特許文献2に開示の方法は、噴流方向の制御は達成できるものの、噴流の流速を増減させる制御には適用できない課題がある。また、特許文献3に開示の技術では、ランス内部の構造物を移動させるための駆動装置が必要となるほか機械的可動部を持つなどの点で実用的でない問題があった。 Further, although the method disclosed in Patent Document 2 can achieve control of the jet direction, there is a problem that it cannot be applied to control of increasing or decreasing the flow velocity of the jet. Further, the technique disclosed in Patent Document 3 has a problem that it is not practical in that a drive device for moving the structure inside the lance is required and a mechanically movable part is provided.

本発明は、このような事情に鑑みてなされたものであって、反応容器に装入した溶鉄に酸素含有ガスを吹き付けて行う精錬、例えば、溶鋼の脱炭精錬や溶銑の脱りん吹錬を行う際に1本の上吹きランスを用いて、ランスノズルチップやランス高さ、酸素含有ガス流量を変更することなく、ランスノズルに機械的可動部を用いることなく、酸素含有ガス噴流の流速を制御し、歩留向上や高速吹錬を達成することができる上吹きランスおよびそれを用いた溶鉄の精錬方法を提供することを目的とする。 The present invention has been made in view of such circumstances, and refining performed by spraying an oxygen-containing gas onto the molten iron charged in the reaction vessel, for example, decarburization of molten steel or dephosphorization of hot metal. By using one top-blown lance, the flow velocity of the oxygen-containing gas jet can be adjusted without changing the lance nozzle tip, lance height, or oxygen-containing gas flow rate, and without using mechanical moving parts for the lance nozzle. It is an object of the present invention to provide a top-blown lance that can be controlled to improve the yield and achieve high-speed smelting, and a method for refining molten iron using the lance.

上記課題を有利に解決する本発明の上吹きランスは、反応容器に収容された溶鉄に酸素含有ガスを吹き付けるための上吹きランスであって、上記上吹きランスの外殻を貫通して、上記酸素含有ガスを噴射させる、1個以上の吹錬用主孔と、該吹錬用主孔の軸心に向けて制御用ガスを噴出させるために上記吹錬用主孔の内壁面に配置された開口部を有する制御用ガス供給路と、上記吹錬用主孔の入口から上記酸素含有ガスを供給するメイン酸素供給手段と、上記制御用ガス供給路に上記制御用ガスを供給する制御用ガス供給手段とを有し、上記制御用ガス供給路の上記開口部近傍に絞り部を有することを特徴とする。 The top-blown lance of the present invention that advantageously solves the above problems is a top-blown lance for blowing an oxygen-containing gas onto the molten iron contained in the reaction vessel, and penetrates the outer shell of the top-blown lance to obtain the above. One or more main holes for blowing to inject oxygen-containing gas, and arranged on the inner wall surface of the main holes for blowing to inject control gas toward the axis of the main holes for blowing. A control gas supply path having an opening, a main oxygen supply means for supplying the oxygen-containing gas from the inlet of the blowing main hole, and a control gas for supplying the control gas to the control gas supply path. It is characterized by having a gas supply means and a throttle portion in the vicinity of the opening of the control gas supply path.

なお、本発明にかかる上吹きランスは、
a.上記開口部が上記吹錬用主孔の内壁面の周方向に略等間隔に2個以上配置されること、
b.上記開口部の円周方向長さの合計が上記吹錬用主孔の内壁面の全周の25%以上100%以下を占める1個以上のスリット形状を有すること、
c.上記制御用ガス供給路の上記開口部の開口断面積Asと上記絞り部の断面積Amの比が1.02≦As/Am≦1.40であることがより好ましい解決手段になり得るものと考えられる。
The top-blown lance according to the present invention is
a. Two or more of the openings are arranged at substantially equal intervals in the circumferential direction of the inner wall surface of the main hole for blowing.
b. Having one or more slit shapes in which the total circumferential length of the opening occupies 25% or more and 100% or less of the entire circumference of the inner wall surface of the main hole for blowing.
c. It can be a more preferable solution that the ratio of the cross-sectional area As of the opening of the control gas supply path to the cross-section Am of the throttle portion is 1.02 ≦ As / Am ≦ 1.40. Conceivable.

上記課題を有利に解決する溶鉄の精錬方法は、上記上吹きランスを用いた溶鉄の精錬方法であって、上記制御用ガス供給路の上記開口部から供給されるガス流量Qs(Nm/min)と、上記吹錬用主孔の入口から供給されるガス流量Qm(Nm/min)および上記制御用ガス供給路の上記開口部から供給されるガス流量Qsの合計流量との比が、0.02≦Qs/(Qm+Qs)≦0.40であることを特徴とする。 The method for refining molten iron that advantageously solves the above problems is the method for refining molten iron using the top-blown lance, and the gas flow rate Qs (Nm 3 / min) supplied from the opening of the control gas supply path. ) And the total flow rate of the gas flow rate Qm (Nm 3 / min) supplied from the inlet of the main hole for blowing and the gas flow rate Qs supplied from the opening of the control gas supply path. It is characterized in that 0.02 ≦ Qs / (Qm + Qs) ≦ 0.40.

本発明によれば、上吹きランスの吹錬用主孔の側壁から制御ガスを導入することで、機械的可動部を用いることなく、主流の流路断面積を変更することが可能になり、主流の噴出流速を変更することが可能となる。また、地金付着で操業が阻害されやすい機械的なノズル形状変更方式によらずに流速変更が可能となる。その結果、この上吹きランスを用いて溶鉄の精錬を効率化でき、たとえば、脱炭精錬における脱炭速度が向上し、生産効率を改善することができる。 According to the present invention, by introducing the control gas from the side wall of the main hole for blowing of the top blowing lance, it is possible to change the cross section of the mainstream flow path without using a mechanically movable part. It is possible to change the mainstream ejection flow velocity. In addition, the flow velocity can be changed without using a mechanical nozzle shape changing method in which the operation is easily hindered by the adhesion of the bare metal. As a result, this top-blown lance can be used to improve the efficiency of refining molten iron, for example, the decarburization rate in decarburization refining can be improved, and the production efficiency can be improved.

本発明の実施形態における上吹きランス先端の縦断面を示す模式図である。It is a schematic diagram which shows the vertical cross section of the tip of the top blowing lance in embodiment of this invention. 本発明の一実施形態を示す主流の縮流とよどみ領域を示すランス縦断面の模式図である。It is a schematic diagram of the lance longitudinal section which shows the contraction flow and stagnation area of the mainstream which shows one Embodiment of this invention. 本発明の一実施形態を示す絞り部を設けた制御用ガス供給路を有するランスの縦断面を示す模式図である。It is a schematic diagram which shows the vertical cross section of the lance which has the control gas supply path provided with the throttle part which shows one Embodiment of this invention. 本発明の一実施形態を示す絞り部を設けた制御用ガス供給路を有するランスのA−A’視断面を示す拡大模式図であり、制御用ガス供給路の開口部が(a)丸孔の場合、(b)スリット形状の場合である。It is an enlarged schematic view which shows the AA'view section of the lance which has the control gas supply path provided with the throttle part which shows one Embodiment of this invention, and the opening of the control gas supply path is (a) a round hole. In the case of (b), it is a case of a slit shape.

以下、図面を用いて本発明の実施形態について説明する。
図1は、本発明の実施形態における転炉用上吹きランス1の先端の縦断面を示す模式図である。なお、図1では、上吹きランス1の下端部を示している。上吹きランス1は、酸素含有ガスを反応容器内湯面に向かって噴射する吹錬用主孔3を1個以上(ここでは、複数個)備えており、吹錬用主孔3内に制御用ガスを噴出させるためにそれぞれの吹錬用主孔3の内壁面に配置された開口部41を有する制御用ガス供給路4を備えている。この制御用ガスは、吹錬用主孔3の軸心に向かって噴出させるように開口部41が構成されている。上吹きランス1は、冷却水循環路2を有している。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a vertical cross section of the tip of a converter top-blown lance 1 according to an embodiment of the present invention. Note that FIG. 1 shows the lower end of the top blow lance 1. The top blowing lance 1 is provided with one or more (here, a plurality of) blowing main holes 3 for injecting oxygen-containing gas toward the hot water surface in the reaction vessel, and is used for control in the blowing main holes 3. A control gas supply path 4 having an opening 41 arranged on the inner wall surface of each blowing main hole 3 for ejecting gas is provided. The opening 41 is configured so that the control gas is ejected toward the axis of the main hole 3 for blowing. The top blown lance 1 has a cooling water circulation path 2.

本発明では、図1に示すような上吹きランスのノズル(吹錬用主孔3)内において、主流の進行方向に対して、別方向から制御ガスを主流に衝突させることにより、主流の流路を変更し、流速を制御するものである。この上吹きランスには、吹錬用主孔3の入口から酸素含有ガスを供給するメイン酸素供給手段(図示しない)および制御用ガス供給路4に制御用ガスを供給する制御用ガス供給手段(図示しない)を有している。本来主流が流れる流路はノズルの断面全体であるが、制御ガスを導入した場合は主流が制御ガス流を避けて流れるために、主流の流路断面積が制限されることとなる。また、図2のように制御用ガス供給路4の開口部41の近傍に流速の遅いよどみ領域5が形成されるため、この領域も主流が通過しない。その結果、ノズル内部に絞り部(スロート)が形成されて、あたかもラバールノズルであるかのような挙動をふるまう。このため、ノズル出口にて適正膨張となり、流速が向上する。 In the present invention, in the nozzle (main hole 3 for blowing) of the upper blowing lance as shown in FIG. 1, the mainstream flow is caused by colliding the control gas with the mainstream from a different direction with respect to the traveling direction of the mainstream. It changes the path and controls the flow velocity. The top blowing lance is provided with a main oxygen supply means (not shown) that supplies oxygen-containing gas from the inlet of the main hole 3 for blowing, and a control gas supply means (not shown) that supplies control gas to the control gas supply path 4. Not shown). Originally, the flow path through which the mainstream flows is the entire cross section of the nozzle, but when the control gas is introduced, the mainstream flows while avoiding the control gas flow, so that the cross-sectional area of the mainstream flow path is limited. Further, as shown in FIG. 2, since the stagnation region 5 having a slow flow velocity is formed in the vicinity of the opening 41 of the control gas supply path 4, the mainstream does not pass through this region either. As a result, a diaphragm portion (throat) is formed inside the nozzle, and the nozzle behaves as if it were a Laval nozzle. Therefore, proper expansion occurs at the nozzle outlet, and the flow velocity is improved.

本発明の原理は、流体現象を利用した素子のひとつである流体素子利用したものである。流体素子とは、噴流と側壁との干渉効果、噴流と噴流との衝突効果、渦により生じる流体現象、噴流自体の流速変動による効果によって得られる機能を利用する素子の総称であり、流体力学の分野で研究されている。例えば、噴流の流路の出口付近に、噴流と直角方向に制御用流体の供給口を配した形をとる。制御用流体の供給口から噴流へ流体を導入すると、制御用流体により噴流が縮流されて、噴流の一部の断面積が小さくなり、直線状の流路であってもラバールノズルの流路であるような挙動を示す。これにより、吹錬用主孔3の出口31で、吹錬用主孔3からの噴射ガス(酸素含有ガスと制御用ガスの混合ガス)の流速が上昇する。流体素子は機械的可動部を必要としないところに利点がある。 The principle of the present invention is to use a fluid element, which is one of the elements utilizing the fluid phenomenon. A fluid element is a general term for elements that utilize the functions obtained by the interference effect between a jet and a side wall, the collision effect between a jet and a jet, the fluid phenomenon caused by a vortex, and the effect of fluctuations in the flow velocity of the jet itself. It is being studied in the field. For example, a control fluid supply port is arranged in a direction perpendicular to the jet flow near the outlet of the jet flow path. When a fluid is introduced into the jet from the control fluid supply port, the jet is contracted by the control fluid, and the cross section of a part of the jet becomes smaller. Even if it is a linear flow path, it is in the Laval nozzle flow path. It behaves in a certain way. As a result, the flow velocity of the injection gas (mixed gas of oxygen-containing gas and control gas) from the blowing main hole 3 increases at the outlet 31 of the blowing main hole 3. Fluid elements have the advantage that they do not require mechanical moving parts.

本発明の上吹きランスの吹錬用主孔3内では、主流に対する制御ガスの貫入深さが深く、なおかつよどみ領域が広いほど主流の流路断面積が縮小され、主流の流速がより上昇する。制御ガスの貫入深さを深くすれば、自然とよどみ領域も広くなるため、貫入深さのみに着目すれば良い。貫入深さを深くするためには制御ガスの噴出流速を上昇させることが有効である。このとき、制御ガス流速を上げるために制御ガス流量を増やした場合、脱炭末期に酸素流量を低減したいというニーズにそぐわないものとなってしまう。そこで、本発明では、図3のように制御用ガス供給路4の開口部41の直前の流路内に絞り部(スロート)6を設けてラバール形状とする。このような構成とすることで、制御ガス流量を増やすことなく制御ガスの流速を向上させることができる。 In the blowing main hole 3 of the top blowing lance of the present invention, the deeper the penetration depth of the control gas into the mainstream and the wider the stagnation region, the smaller the cross section of the mainstream flow path and the higher the mainstream flow velocity. .. If the penetration depth of the control gas is increased, the stagnation area naturally becomes wider, so it is only necessary to pay attention to the penetration depth. In order to increase the penetration depth, it is effective to increase the ejection flow velocity of the control gas. At this time, if the control gas flow rate is increased in order to increase the control gas flow rate, the need for reducing the oxygen flow rate at the final stage of decarburization is not met. Therefore, in the present invention, as shown in FIG. 3, a throttle portion (throat) 6 is provided in the flow path immediately before the opening 41 of the control gas supply path 4 to form a rubberal shape. With such a configuration, the flow velocity of the control gas can be improved without increasing the flow rate of the control gas.

制御用ガス供給路4の開口部41の形状は、丸孔や多角形、部分スリット、全周スリット等、どのような形状でも構わない。制御ガスを軸心に向けて噴出させることが主流を絞るうえで重要である。また、制御用ガス供給路4の開口部41を2個以上配置する場合は吹錬用主孔3の内壁面の円周方向に略等間隔に配置する。そのような配置とすることで、円周方向でバランスよくよどみ部が構成され、主流の縮流効果が高まるという効果が得られる。スリット形状の場合、吹錬用主孔3の内壁面の周長に対するスリット部の割合が25%以上100%以下である必要がある。スリット部の割合が25%未満では、主流の縮流効果が小さくなるおそれがある。吹錬用主孔3の内壁面の周長に対するスリット部の割合が、50〜100%の範囲にあることが好ましい。一方、開口部41の形状がスリット形状以外の丸孔や多角形孔の場合、吹錬用主孔3の内壁面の周長に対する開口部の円周方向長さの合計が25%以上90%以下の範囲にあることが好ましく、50%以上90%以下の範囲にあることがさらに好ましい。なお、上記の「円周方向に略等間隔」とは、それぞれの隣接する開口部41同士の円周方向中心位置の距離Sが、全ての隣接する開口部41同士の円周方向中心位置の距離Sの平均値に対して±20%以内に収まっているという意味である。 The shape of the opening 41 of the control gas supply path 4 may be any shape such as a round hole, a polygon, a partial slit, and an all-around slit. It is important to eject the control gas toward the axis in order to narrow down the mainstream. When two or more openings 41 of the control gas supply path 4 are arranged, they are arranged at substantially equal intervals in the circumferential direction of the inner wall surface of the main hole 3 for blowing. With such an arrangement, a well-balanced stagnation portion is formed in the circumferential direction, and the effect of enhancing the mainstream contraction effect can be obtained. In the case of the slit shape, the ratio of the slit portion to the peripheral length of the inner wall surface of the main hole 3 for blowing must be 25% or more and 100% or less. If the ratio of the slit portion is less than 25%, the mainstream contraction effect may be reduced. The ratio of the slit portion to the peripheral length of the inner wall surface of the main hole 3 for blowing is preferably in the range of 50 to 100%. On the other hand, when the shape of the opening 41 is a round hole or a polygonal hole other than the slit shape, the total circumferential length of the opening with respect to the peripheral length of the inner wall surface of the main hole 3 for blowing is 25% or more and 90%. It is preferably in the following range, and more preferably in the range of 50% or more and 90% or less. The above-mentioned "approximately equal intervals in the circumferential direction" means that the distance S at the center position in the circumferential direction between the adjacent openings 41 is the center position in the circumferential direction between all the adjacent openings 41. It means that it is within ± 20% of the average value of the distance S.

制御用ガス供給路4の絞り部6の最適な形状は、制御用ガス供給路4の開口部41の形状、設備の制御ガスの供給圧等の設定値によって変わってくるため、一概に規定することは難しいが、ラバールノズルにおいて、一般的な適正膨張条件となる開口断面積比の前後とするべきと考えられる。図3の吹錬用主孔3のA−A’視断面を拡大した模式図で図4に示す。図4(a)は制御用ガス供給路4の開口部41の形状が丸孔の場合、図4(b)は制御用ガス供給路4の開口部41の形状が部分スリット形状の場合を表す。丸孔(図4(a))の場合には、制御用ガス供給路4の円形断面のうち最も断面積の小さな部分である絞り部6での制御用ガス供給路4の断面積が絞り部6の断面積Amであり、丸孔の中心軸が開口部41と交わる位置の制御用ガス供給路4の断面積が開口部断面積Asとなる。スリット形状(図4(b))の場合には、制御用ガス供給路のスリット幅の最も小さな位置が絞り部6であり、円周方向の絞り部6長さと絞り部6のスリット幅との積が絞り部6の断面積Amとなり、開口部41の円周方向長さと開口部41のスリット幅との積が開口断面積Asとなる。制御用ガス供給路4の開口部41の開口断面積Asと絞り部6の断面積Amの比、つまり、開口断面積比As/Amを1.02≦As/Am≦1.40の範囲とすることが望ましい。ここで、開口断面積比As/Amが1.02未満では、ストレートノズルと変わらず、制御ガスの増速効果が得られないおそれがある。一方、開口断面積比が1.40を超えると、適正開口比から遠ざかり、制御ガス噴流の流速が低下して貫入深さが浅くなるため、縮流効果が得られなくなるおそれがある。より好ましい開口断面積比は1.05≦As/Am≦1.30の範囲である。 The optimum shape of the throttle portion 6 of the control gas supply path 4 varies depending on the shape of the opening 41 of the control gas supply path 4 and the set values such as the supply pressure of the control gas of the equipment. Although it is difficult to do so, it is considered that it should be before and after the opening cross-section ratio, which is a general proper expansion condition for Laval nozzles. FIG. 4 is an enlarged schematic view of the AA'viewing cross section of the main hole 3 for blowing in FIG. FIG. 4A shows a case where the shape of the opening 41 of the control gas supply path 4 is a round hole, and FIG. 4B shows a case where the shape of the opening 41 of the control gas supply path 4 is a partial slit shape. .. In the case of a round hole (FIG. 4A), the cross-sectional area of the control gas supply path 4 in the throttle portion 6, which is the smallest cross-section of the circular cross section of the control gas supply passage 4, is the throttle portion. The cross-sectional area of 6 is Am, and the cross-sectional area of the control gas supply path 4 at the position where the central axis of the round hole intersects the opening 41 is the opening cross-sectional area As. In the case of the slit shape (FIG. 4B), the position where the slit width of the control gas supply path is the smallest is the throttle portion 6, and the length of the throttle portion 6 in the circumferential direction and the slit width of the throttle portion 6 are The product is the cross-sectional area Am of the throttle portion 6, and the product of the circumferential length of the opening 41 and the slit width of the opening 41 is the opening cross-sectional area As. The ratio of the opening cross section As of the opening 41 of the control gas supply path 4 to the cross section Am of the throttle portion 6, that is, the opening cross section ratio As / Am is in the range of 1.02 ≦ As / Am ≦ 1.40. It is desirable to do. Here, if the opening cross-section ratio As / Am is less than 1.02, the effect of increasing the speed of the control gas may not be obtained, which is the same as that of the straight nozzle. On the other hand, if the opening cross-section ratio exceeds 1.40, the opening ratio moves away from the proper opening ratio, the flow velocity of the control gas jet decreases, and the penetration depth becomes shallow, so that the flow reduction effect may not be obtained. A more preferable opening cross-section ratio is in the range of 1.05 ≦ As / Am ≦ 1.30.

本発明の上吹きランス1を用いて、溶鉄の精錬に適用する場合には、吹錬用主孔3の入口から供給されるガス流量Qm(Nm/min)に対する制御用ガス供給路4の開口部41から供給されるガス流量Qs(Nm/min)の比は最適なバランスが存在する。設備のスペックによって最適な制御ガス流量比Qs/(Qm+Qs)は変わってくるため一概に規定することは難しいが、制御ガスが少なすぎると主流の縮流効果が小さくなり、制御ガスが多すぎると主流に対する貫入が深くなり、主流の流れを大きく乱す傾向にあるため、おおまかには0.02≦Qs/(Qm+Qs)≦0.40となる条件の範囲で、溶鉄を精錬処理することが好ましい。より好ましくは、0.15≦Qs/(Qm+Qs)≦0.25の範囲である。 When the top-blown lance 1 of the present invention is applied to the refining of molten iron, the control gas supply path 4 with respect to the gas flow rate Qm (Nm 3 / min) supplied from the inlet of the blowing main hole 3 The ratio of the gas flow rate Qs (Nm 3 / min) supplied from the opening 41 has an optimum balance. Since the optimum control gas flow rate ratio Qs / (Qm + Qs) changes depending on the equipment specifications, it is difficult to unconditionally specify it, but if the control gas is too small, the mainstream contraction effect will be small, and if the control gas is too large. Since the penetration into the mainstream becomes deep and the mainstream flow tends to be greatly disturbed, it is preferable to refine the molten iron within the condition of roughly 0.02 ≦ Qs / (Qm + Qs) ≦ 0.40. More preferably, it is in the range of 0.15 ≦ Qs / (Qm + Qs) ≦ 0.25.

本発明で用いる酸素含有ガスとしては、主流および制御ガスともに、純酸素としてもよいし、火点温度制御等を目的として、酸素ガスに、不活性ガスや窒素ガス、COガスを混合してもよい。また、主流と制御ガスのガス種を変えてもよい。ガス種を変える場合は、主流に酸素ガスを用いることが好ましい。 As the oxygen-containing gas used in the present invention, both the mainstream and the control gas may be pure oxygen, or an inert gas, a nitrogen gas, or a CO gas may be mixed with the oxygen gas for the purpose of controlling the fire point temperature or the like. Good. Moreover, the gas type of the mainstream and the control gas may be changed. When changing the gas type, it is preferable to use oxygen gas as the mainstream.

本発明の上吹きランスを用いた制御ガスによる上吹きランスから吹き付ける酸素ガス噴流の制御は、脱炭末期において撹拌能力向上を達成することを主目的としたものであるが、本発明は制御ガスの流量に応じてソフトブローからハードブローまで幅広く、主流の流速を変更できるものであり、他の用途への応用範囲が広い。すなわち、ソフトブローは、制御用ガス供給路4の開口部41から制御用ガスを供給しないことによって実現することができ、一方、ハードブローは、制御用ガス供給路4の開口部41から制御用ガスを適切に供給することによって実現することができる。例えば、ソフトブロー化による2次燃焼量増大による着熱向上、およびスラグ中のT.Feも制御することができるため、溶銑の脱りん処理に適用することもできる。すなわち、本発明は、転炉脱炭処理に限らず、転炉脱Si、脱P、電気炉、真空脱ガス等、上吹きで精錬を行う方式であればどのようなプロセスにも適用可能である。 The control of the oxygen gas jet blown from the top-blown lance by the control gas using the top-blown lance of the present invention is mainly aimed at achieving an improvement in stirring capacity at the final stage of decarburization, but the present invention is a controlled gas. The mainstream flow velocity can be changed in a wide range from soft blow to hard blow according to the flow rate of the gas, and the range of application to other applications is wide. That is, the soft blow can be realized by not supplying the control gas from the opening 41 of the control gas supply path 4, while the hard blow is for control from the opening 41 of the control gas supply path 4. This can be achieved by properly supplying the gas. For example, the heat transfer is improved by increasing the secondary combustion amount by soft blowing, and the T.I. Since Fe can also be controlled, it can also be applied to the dephosphorization treatment of hot metal. That is, the present invention is not limited to the converter decarburization treatment, and can be applied to any process such as converter de-Si, de-P, electric furnace, vacuum degassing, etc., as long as it is a method of refining by top blowing. ..

本発明の効果を確認するため、容量250トン規模の転炉を模擬した熱流体シミュレーションを実施した。シミュレーションには汎用熱流体ソフトウェアであるSTAR-CCM+(Ver. 11.02)を用いた。吹錬用主孔3はストレート形とし、その管径Dmは70mmとした。吹錬用主孔内での制御用ガスの開口部の位置は、管径Dmと開口部から吹錬用主孔出口までの距離Laとの比で、La/Dm=1.5とした。制御用ガス供給路4の開口部41は4つの丸孔、部分スリットおよび全周スリットとし、主流に対し、垂直に噴出する方向とした。制御用ガス供給路4が丸孔(図4(a))の場合、絞り部6は丸孔と同軸の円形断面となるように形成させ、開口部41までの末拡がり部は円錐台の側面の一部をなすようにテーパー状に形成させた。このとき、制御用ガス供給路4の開口断面積Asおよび絞り部6の断面積Amは、丸孔のそれぞれの軸方向位置で、丸孔の中心軸に垂直な平面において制御用ガス供給路4の壁面で囲まれる、それぞれ最大の円の面積および最小の円の面積である。また、制御用ガス供給路4が部分スリットまたは全周スリット(図4(b))の場合、絞り部6及び開口部41までの末拡がり部は、吹錬用主孔の軸心に向けて放射状に形成させたスリット状の制御用ガス供給路4の対向する壁面の間隔を、制御用ガスの流れる方向7である吹錬用主孔の径方向に変更し、かつ吹錬用主孔の周方向には一定となるように形成させた。このとき、制御用ガス供給路4の開口断面積Asおよび絞り部6の断面積Amは、それぞれの径方向位置での主孔の軸心から周方向に等距離の曲面を横切る制御用ガス供給路4の断面積である。各々制御用ガス供給路で開口断面積比As/Amを変更して比較を行った。表1に示した条件にて上吹きランスから酸素を供給し、吹錬用主孔出口31から2m下に位置する溶鋼相当面での最大流速Vmaxを比較した。 In order to confirm the effect of the present invention, a thermo-fluid simulation simulating a converter having a capacity of 250 tons was carried out. STAR-CCM + (Ver. 11.02), which is general-purpose thermo-fluid software, was used for the simulation. The main hole 3 for blowing was a straight type, and its pipe diameter Dm was 70 mm. The position of the opening of the control gas in the main hole for blowing was La / Dm = 1.5, which is the ratio of the pipe diameter Dm to the distance La from the opening to the outlet of the main hole for blowing. The opening 41 of the control gas supply path 4 has four round holes, a partial slit, and a full-circle slit, and the direction of ejection is perpendicular to the mainstream. When the control gas supply path 4 is a round hole (FIG. 4A), the throttle portion 6 is formed so as to have a circular cross section coaxial with the round hole, and the divergent portion up to the opening 41 is the side surface of the truncated cone. It was formed in a tapered shape so as to form a part of. At this time, the opening cross-sectional area As of the control gas supply path 4 and the cross-sectional area Am of the throttle portion 6 are the control gas supply paths 4 in the plane perpendicular to the central axis of the round hole at the respective axial positions of the round hole. The area of the largest circle and the area of the smallest circle, respectively, surrounded by the walls of. Further, when the control gas supply path 4 is a partial slit or a full-circle slit (FIG. 4B), the divergent portion up to the throttle portion 6 and the opening 41 is directed toward the axial center of the main hole for blowing. The distance between the opposing wall surfaces of the slit-shaped control gas supply path 4 formed radially is changed to the radial direction of the blowing main hole, which is the direction 7 in which the control gas flows, and the blowing main hole It was formed so as to be constant in the circumferential direction. At this time, the opening cross-sectional area As of the control gas supply path 4 and the cross-sectional area Am of the throttle portion 6 cross a curved surface equidistant from the axial center of the main hole at each radial position to supply the control gas. It is a cross section of the road 4. Comparisons were made by changing the opening cross-section ratio As / Am in each control gas supply path. Oxygen was supplied from the top blown lance under the conditions shown in Table 1, and the maximum flow velocity Vmax on the molten steel equivalent surface located 2 m below the main hole outlet 31 for blowing was compared.

表1にシミュレーションの結果を併せて示す。制御ガスを導入しない条件No.1の最大湯面到達流速V=110m/secに対し、条件No.2、4、6および8の比較例は最大湯面到達流速Vmaxが向上し、条件No.1に対する増速比Vmax/Vが1.00を超えていることから、制御ガス導入による湯面到達流速の向上効果が確認できた。さらに条件No.2、4、6および8の比較例に対し、それぞれラバール型の制御用ガス供給路をもつ条件No.3、5、7および9の発明例では湯面到達流速Vmaxがさらに向上している。つまり、制御用ガス供給路4の開口部41の開口断面積比As/Amが1.00の場合に比べて、開口断面積比As/Am=1.10にラバールノズル化した例では全て主流の流速が向上していることがわかる。したがって、制御ガスの流量を増やすことなく湯面到達流速が向上していることが示された。また、4分割の部分スリットで開口断面積比As/Amを1.05、1.4と変更した条件No.9および10においても、開口断面積比As/Amが1.00の場合(条件No.3)よりも主流の流速が向上した。 Table 1 also shows the results of the simulation. Condition No. that does not introduce control gas. With respect to the maximum flow velocity V 0 = 110 m / sec at the maximum molten metal level of 1, the condition No. In the comparative examples of Nos. 2, 4, 6 and 8, the maximum flow velocity Vmax at the molten metal surface was improved, and the condition No. Since the acceleration ratio Vmax / V 0 with respect to 1 exceeds 1.00, the effect of improving the flow velocity reaching the molten metal surface by introducing the control gas can be confirmed. Furthermore, condition No. Compared to the comparative examples of 2, 4, 6 and 8, the condition No. 2 having a rubber-type control gas supply path, respectively. In the examples of the inventions 3, 5, 7 and 9, the flow velocity Vmax reaching the surface of the molten metal is further improved. That is, compared to the case where the opening cross-section ratio As / Am of the opening 41 of the control gas supply path 4 is 1.00, all the examples in which the Laval nozzle is used so that the opening cross-section ratio As / Am = 1.10 are mainstream. It can be seen that the flow velocity is improving. Therefore, it was shown that the flow velocity reaching the molten metal surface was improved without increasing the flow rate of the control gas. Further, the condition No. in which the opening cross-sectional area ratio As / Am was changed to 1.05 and 1.4 in the partial slit divided into four parts. In 9 and 10, the mainstream flow velocity was also improved as compared with the case where the opening cross-section ratio As / Am was 1.00 (condition No. 3).

撹拌力の指標となる湯面動圧は、湯面到達流速Vの2乗で計算できることから、5%の流速上昇による攪拌力増加効果は、1.05=1.10と10%の撹拌力の向上となることが分かる。これは、脱炭末期において、単に酸素流量を上げてしまうと鉄酸化を促進して歩留まりが悪化してしまうのに対し、本発明に基づき、主孔内への制御ガス導入により、流量を上げずに動圧を上げることができたことに意味がある。以上の結果から、制御用ガス供給流路4に絞り部6を設けることによって、主流の流速をより向上させることが可能であると示された。 Molten metal surface dynamic pressure indicative of stirring force, since it can be computed by the square of the molten metal surface reaches the flow velocity V, stirring force increasing effect with 5% of the flow rate increase is 1.05 2 = 1.10 10% of the agitation It can be seen that the power is improved. This is because, at the end of decarburization, if the oxygen flow rate is simply increased, iron oxidation is promoted and the yield is deteriorated. On the other hand, based on the present invention, the flow rate is increased by introducing a control gas into the main hole. It is significant that we were able to raise the dynamic pressure without doing so. From the above results, it was shown that the mainstream flow velocity can be further improved by providing the throttle portion 6 in the control gas supply flow path 4.

上記実施例は、溶鋼の脱炭精錬における脱炭末期への適用例を示したが、本発明の上吹きランスは、主流の流速制御を必要とする上吹き精錬のいずれに適用しても好適である。 Although the above-mentioned examples have shown an example of application to the final stage of decarburization in decarburization of molten steel, the top-blown lance of the present invention is suitable for any of top-blown refining that requires mainstream flow velocity control. Is.

1:上吹きランス
2:冷却水循環路
3:吹錬用主孔
31:吹錬用主孔出口
4:制御用ガス供給路
41:開口部
5:よどみ領域
6:絞り部(スロート)
7:制御用ガスの噴出方向
1: Top blow lance 2: Cooling water circulation path 3: Blow main hole 31: Blow main hole outlet 4: Control gas supply path 41: Opening 5: Stagnation area 6: Squeeze part (throat)
7: Ejection direction of control gas

Claims (5)

反応容器に収容された溶鉄に酸素含有ガスを吹き付けるための上吹きランスであって、
前記上吹きランスの外殻を貫通して、前記酸素含有ガスを噴射させる、1個以上の吹錬用主孔3と、
該吹錬用主孔3の軸心に向けて制御用ガスを噴出させるために前記吹錬用主孔3の内壁面に配置された開口部41を有する制御用ガス供給路4と、
前記吹錬用主孔3の入口から前記酸素含有ガスを供給するメイン酸素供給手段と、
前記制御用ガス供給路4に前記制御用ガスを供給する制御用ガス供給手段とを有し、
前記制御用ガス供給路4の前記開口部41近傍に絞り部6を有することを特徴とする上吹きランス。
A top-blown lance for blowing oxygen-containing gas onto the molten iron contained in the reaction vessel.
One or more main holes 3 for blowing through the outer shell of the top blowing lance to inject the oxygen-containing gas, and
A control gas supply path 4 having an opening 41 arranged on the inner wall surface of the blowing main hole 3 for ejecting a control gas toward the axial center of the blowing main hole 3.
The main oxygen supply means for supplying the oxygen-containing gas from the inlet of the main hole 3 for blowing, and
It has a control gas supply means for supplying the control gas to the control gas supply path 4.
A top-blowing lance characterized by having a throttle portion 6 in the vicinity of the opening 41 of the control gas supply path 4.
前記開口部41が前記吹錬用主孔3の内壁面の周方向に略等間隔に2個以上配置されることを特徴とする請求項1に記載の上吹きランス。 The upper blowing lance according to claim 1, wherein two or more of the openings 41 are arranged at substantially equal intervals in the circumferential direction of the inner wall surface of the blowing main hole 3. 前記開口部41の円周方向長さの合計が前記吹錬用主孔3の内壁面の全周の25%以上100%以下を占める1個以上のスリット形状を有することを特徴とする請求項1に記載の上吹きランス。 The claim is characterized in that the total circumferential length of the opening 41 has one or more slit shapes occupying 25% or more and 100% or less of the entire circumference of the inner wall surface of the main hole 3 for blowing. Top-blown lance described in 1. 前記制御用ガス供給路4の前記開口部41の開口断面積Asと前記絞り部6の断面積Amの比が1.02≦As/Am≦1.40であることを特徴とする請求項1〜3のいずれか1項に記載の上吹きランス。 Claim 1 is characterized in that the ratio of the opening cross-sectional area As of the opening 41 of the control gas supply path 4 to the cross-sectional area Am of the throttle portion 6 is 1.02 ≦ As / Am ≦ 1.40. The top-blown lance according to any one of 3 to 3. 請求項1〜4のいずれか1項に記載の上吹きランスを用いた溶鉄の精錬方法であって、
前記制御用ガス供給路4の前記開口部41から供給されるガス流量Qs(Nm/min)と、前記吹錬用主孔3の入口から供給されるガス流量Qm(Nm/min)および前記制御用ガス供給路4の前記開口部41から供給されるガス流量Qsの合計流量との比が、
0.02≦Qs/(Qm+Qs)≦0.40
であることを特徴とする溶鉄の精錬方法。
A method for refining molten iron using the top-blown lance according to any one of claims 1 to 4.
The gas flow rate Qs (Nm 3 / min) supplied from the opening 41 of the control gas supply path 4, the gas flow rate Qm (Nm 3 / min) supplied from the inlet of the blowing main hole 3, and the gas flow rate Qs (Nm 3 / min). The ratio of the gas flow rate Qs supplied from the opening 41 of the control gas supply path 4 to the total flow rate is
0.02 ≤ Qs / (Qm + Qs) ≤ 0.40
A refining method for molten iron, which is characterized by being.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020190030A (en) * 2019-05-20 2020-11-26 Jfeスチール株式会社 Top-blown lance and refining method of molten iron therewith

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JPH08269530A (en) * 1995-04-03 1996-10-15 Kawasaki Steel Corp Top blowing lance
JPH09209021A (en) * 1996-02-05 1997-08-12 Nippon Steel Corp Molten iron refining lance and method
JP2000234116A (en) * 1998-12-15 2000-08-29 Nippon Steel Corp Laval nozzle for converter blowing and operation using this
JP2007077489A (en) * 2005-09-16 2007-03-29 Jfe Steel Kk Top-blown lance and method for operating converter using this lance

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0728952U (en) * 1993-06-24 1995-05-30 新日本製鐵株式会社 Steelmaking lance
JPH08269530A (en) * 1995-04-03 1996-10-15 Kawasaki Steel Corp Top blowing lance
JPH09209021A (en) * 1996-02-05 1997-08-12 Nippon Steel Corp Molten iron refining lance and method
JP2000234116A (en) * 1998-12-15 2000-08-29 Nippon Steel Corp Laval nozzle for converter blowing and operation using this
JP2007077489A (en) * 2005-09-16 2007-03-29 Jfe Steel Kk Top-blown lance and method for operating converter using this lance

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020190030A (en) * 2019-05-20 2020-11-26 Jfeスチール株式会社 Top-blown lance and refining method of molten iron therewith
JP7036147B2 (en) 2019-05-20 2022-03-15 Jfeスチール株式会社 Top-blown lance and refining method of molten iron using it

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