JP2007247045A - Method for desulfurizing molten iron - Google Patents

Method for desulfurizing molten iron Download PDF

Info

Publication number
JP2007247045A
JP2007247045A JP2006076243A JP2006076243A JP2007247045A JP 2007247045 A JP2007247045 A JP 2007247045A JP 2006076243 A JP2006076243 A JP 2006076243A JP 2006076243 A JP2006076243 A JP 2006076243A JP 2007247045 A JP2007247045 A JP 2007247045A
Authority
JP
Japan
Prior art keywords
desulfurization
hot metal
lance
desulfurizing agent
agent
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
Application number
JP2006076243A
Other languages
Japanese (ja)
Other versions
JP4961787B2 (en
Inventor
Yuta Hino
雄太 日野
Yoshie Nakai
由枝 中井
Ikuhiro Sumi
郁宏 鷲見
Seiji Nabeshima
誠司 鍋島
Akihiko Inoue
明彦 井上
Shunji Ozuru
俊司 大鶴
Yuichi Uchida
祐一 内田
Original Assignee
Jfe Steel Kk
Jfeスチール株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Jfe Steel Kk, Jfeスチール株式会社 filed Critical Jfe Steel Kk
Priority to JP2006076243A priority Critical patent/JP4961787B2/en
Publication of JP2007247045A publication Critical patent/JP2007247045A/en
Application granted granted Critical
Publication of JP4961787B2 publication Critical patent/JP4961787B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for effectively desulfurizing molten iron with which in the case of applying the desulfurizing treatment to the molten iron by using a mechanical stirring type desulfurizing apparatus, a comparatively simple facility is used and fine granular desulfurizing agent excellent in reactivity is efficiently added into the molten iron and the dispersion of the desulfurizing agent in the molten iron is promoted. <P>SOLUTION: The desulfurizing treatment is applied by top-blown-adding the desulfurizing agent together with gas for carrying through a top-blown lance 5 on the surface of the molten iron 3 while stirring with a stirring blade 4 at the supplying speed of the desulfurizing agent 7 at ≤1.6 kg/min per ton of the molten iron. The desufurizing agent is dispersed into the molten iron and the desulfurization can efficiently be performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、機械攪拌式脱硫装置を用いた溶銑の脱硫方法に関するものである。   The present invention relates to a hot metal desulfurization method using a mechanical stirring desulfurization apparatus.
近年、鋼の高純度化に対する要求が従来にも増して強くなり、これに伴って鋼中の不純物を除去する技術開発が盛んに行われている。今日の精錬プロセスにおいては、転炉での脱炭精錬に先立って溶銑に含有される燐及び硫黄を除去する方法、即ち溶銑の予備処理が一般的に行われている。このうち、溶銑の脱硫処理においては、水平断面がほぼ円形を有する精錬容器内で溶銑を保持し、溶銑上に脱硫剤を添加し、撹拌羽根(「インペラ」とも呼ばれる)と称した羽根を有する回転子を溶銑内に浸漬して回転させ、溶銑及び脱硫剤を攪拌して脱硫する方法(以下、「機械攪拌式脱硫法」という)が広く行われている。この時の脱硫剤としては、石灰(以下、「CaO」と記す)粉を主成分とする脱硫剤や、カルシウムカーバイド(CaC2 )粉などが挙げられるが、安価なCaO粉を主成分とする脱硫剤が広く用いられている。このCaOによる脱硫反応は、下記の(3)式に示される反応式に基づいて進行する。(3)式において、[S]は溶銑中の硫黄、(CaS)はスラグ中のCaS、[O]は溶銑中の酸素を表している。 In recent years, the demand for higher purity of steel has become stronger than ever, and in accordance with this, technological development for removing impurities in steel has been actively conducted. In today's refining process, a method of removing phosphorus and sulfur contained in hot metal prior to decarburization refining in a converter, that is, pretreatment of hot metal is generally performed. Among these, in the hot metal desulfurization treatment, the hot metal is held in a refining vessel having a substantially circular horizontal section, a desulfurizing agent is added onto the hot metal, and a blade called a stirring blade (also referred to as “impeller”) is provided. A method of immersing and rotating a rotor in hot metal and stirring the hot metal and the desulfurizing agent to desulfurize (hereinafter referred to as “mechanical stirring type desulfurization method”) is widely performed. Examples of the desulfurizing agent at this time include a desulfurizing agent mainly composed of lime (hereinafter referred to as “CaO”) powder, calcium carbide (CaC 2 ) powder, and the like, but mainly composed of inexpensive CaO powder. Desulfurizing agents are widely used. This desulfurization reaction by CaO proceeds based on the reaction formula shown by the following formula (3). In the formula (3), [S] represents sulfur in the hot metal, (CaS) represents CaS in the slag, and [O] represents oxygen in the hot metal.
ここで、上記(3)式の反応を進める方法のひとつとして、スラグの滓化を促進させることが挙げられており、このため、CaO系の脱硫剤には、滓化を促進する目的でフッ化カルシウム(CaF2 )などが少量添加されている。しかし近年、フッ素の環境への影響が問題視されており、フッ素を使用しない脱硫剤の開発が望まれている。 Here, as one of the methods for proceeding the reaction of the above formula (3), slag hatching is promoted. For this reason, a CaO-based desulfurizing agent is used for the purpose of promoting hatching. A small amount of calcium fluoride (CaF 2 ) or the like is added. However, in recent years, the influence of fluorine on the environment has been regarded as a problem, and development of a desulfurizing agent that does not use fluorine is desired.
溶鉄の脱硫反応速度を高めるには、溶鉄/脱硫剤間の反応界面積を増加させることが効果的であり、この観点からは、添加する脱硫剤の粒径は細かいほど好ましい。しかし、実機の機械撹拌式脱硫設備では、溶銑を保持した精錬容器の上方から投入シュートを介して脱硫剤を添加する方法が採られており、細粒の脱硫剤を添加した場合、飛散により、溶銑上に到達する脱硫剤の量が低下し、脱硫剤の添加歩留が低下してしまう。そのために、反応効率が低下するといった問題が生じる。更に、CaOは溶銑とは濡れ難い性質を有するため、溶銑に添加されたCaOは互いに凝集してしまい、凝集内部のCaOは未反応のままであるために反応効率が低下するといった問題が生じる。   In order to increase the desulfurization reaction rate of the molten iron, it is effective to increase the reaction interface area between the molten iron and the desulfurizing agent. From this viewpoint, the smaller the particle size of the desulfurizing agent to be added is preferable. However, in the actual machine stirring type desulfurization equipment, a method of adding a desulfurizing agent from the upper part of the refining vessel holding the hot metal via a feeding chute is adopted, and when a fine desulfurizing agent is added, The amount of the desulfurizing agent reaching on the hot metal decreases, and the addition yield of the desulfurizing agent decreases. Therefore, the problem that reaction efficiency falls arises. Further, since CaO has a property that it is difficult to get wet with hot metal, CaO added to the hot metal aggregates with each other, and the CaO inside the aggregate remains unreacted, resulting in a problem that the reaction efficiency is lowered.
これらのことから、溶銑の脱硫反応を促進させる手段のひとつとして、粉体として添加するCaOの凝集を抑制し、溶銑浴内への脱硫剤の浸入を向上させ、溶銑浴内での分散を促進させることが有効であると考えられる。これを実現させる技術として、特許文献1には、精錬容器の側壁に側壁から突出した整流体を設け、回転攪拌した溶銑を整流体に衝突させて下降流を発生させ、この下降流に脱硫剤を巻き込ませる方法が提案されている。また、特許文献2には、回転する撹拌羽根の軸下から脱硫剤を溶銑中に吹き込みながら脱硫する方法が提案されている。
特開昭51−112416号公報 特開2005−68506号公報
Therefore, as one of the means to promote the hot metal desulfurization reaction, the aggregation of CaO added as a powder is suppressed, the penetration of the desulfurizing agent into the hot metal bath is improved, and the dispersion in the hot metal bath is promoted. It is considered to be effective. As a technique for realizing this, Patent Document 1 includes a rectifying body projecting from a side wall of a smelting vessel, causing the molten iron stirred and collided with the rectifying body to generate a downward flow, and a desulfurizing agent is generated in the downward flow. There has been proposed a method for entraining. Patent Document 2 proposes a method of desulfurization while blowing a desulfurizing agent into the hot metal from below the axis of a rotating stirring blade.
Japanese Patent Laid-Open No. 51-112416 JP 2005-68506 A
しかしながら、上記従来技術には以下の問題点がある。即ち、特許文献1に開示されるような整流体を設置する場合、撹拌羽根による回転撹拌力が非常に強いため、その整流体は非常に強化な形状及び材質としなければならない。そのために、整流体の製作及びメンテナンスに多くの労力や費用を費やしてしまうという問題点がある。   However, the above prior art has the following problems. That is, when a rectifying body as disclosed in Patent Document 1 is installed, the rotational stirring force by the stirring blades is very strong, and therefore the rectifying body must have a very strong shape and material. Therefore, there is a problem that much labor and cost are spent on the production and maintenance of the rectifier.
また、特許文献2に開示された攪拌羽根軸下からの粉体吹き込みの場合、脱硫剤粉体は搬送用ガスとともに溶銑中に供給される。このようにして添加した場合、脱硫剤粉体はガス気泡中に補足された状態のまま、浮上するガス気泡とともに浴面上に上昇してしまい、その結果、脱硫剤を浴面上方に添加した場合と同等となり、脱硫反応効率は向上しない可能性がある。更に、攪拌羽根軸下からの粉体吹込みを行うためには、ガス及び粉体を回転軸内へ供給するための装置(例えばロータリージョイントなど)が必要であり、設備費用が増大するという問題点も生じる。   In the case of powder blowing from below the stirring blade shaft disclosed in Patent Document 2, the desulfurizing agent powder is supplied into the hot metal together with the carrier gas. When added in this way, the desulfurizing agent powder is trapped in the gas bubbles and rises on the bath surface together with the rising gas bubbles, and as a result, the desulfurizing agent is added above the bath surface. The desulfurization reaction efficiency may not be improved. Furthermore, in order to blow powder from under the stirring blade shaft, an apparatus (for example, a rotary joint) for supplying gas and powder into the rotating shaft is required, which increases the equipment cost. A point also arises.
本発明は上記事情に鑑みてなされたもので、その目的とするところは、機械攪拌式脱硫装置を用いて溶銑を脱硫処理する際に、比較的簡便な設備を使用して、反応性に優れる細粒の脱硫剤を効率良く溶銑中へ添加し、脱硫剤の溶銑中での分散を促進させて、溶銑を効率良く脱硫する方法を提供することである。   The present invention has been made in view of the above circumstances. The object of the present invention is to use a relatively simple equipment and to have excellent reactivity when desulfurizing hot metal using a mechanical stirring desulfurization apparatus. An object is to provide a method for efficiently desulfurizing hot metal by adding a fine-grain desulfurizing agent to hot metal efficiently and promoting dispersion of the desulfurizing agent in the hot metal.
上記課題を解決するための第1の発明に係る溶銑の脱硫方法は、機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、溶銑トン当たり1.6kg/min以下の脱硫剤の供給速度で、上吹きランスを介して搬送用ガスとともに脱硫剤を上吹き添加して脱硫することを特徴とするものである。   The hot metal desulfurization method according to the first aspect of the present invention for solving the above-described problem is a hot metal desulfurization method using a mechanical stirring desulfurization device, wherein the hot metal is perturbed on the bath surface of the hot metal being stirred by a stirring blade. The desulfurizing agent is desulfurized by adding the desulfurizing agent by blowing up with the carrier gas through the upper blowing lance at a supply rate of the desulfurizing agent of 1.6 kg / min or less.
第2の発明に係る溶銑の脱硫方法は、第1の発明において、前記上吹きランスのランス高さが、該上吹きランスのノズル径に対して、下記の(1)式を満足することを特徴とするものである。但し、(1)式において、hは、上吹きランスのランス高さ(m)、Dは、上吹きランスのノズル径(m)である。   In the hot metal desulfurization method according to the second invention, in the first invention, the lance height of the upper blowing lance satisfies the following expression (1) with respect to the nozzle diameter of the upper blowing lance. It is a feature. However, in Formula (1), h is the lance height (m) of the upper blowing lance, and D is the nozzle diameter (m) of the upper blowing lance.
第3の発明に係る溶銑の脱硫方法は、第1または第2の発明において、前記上吹きランスから供給する搬送用ガスのランスノズル出口における流速が、該上吹きランスのランス高さ及びノズル径に対して、下記の(2)式を満足することを特徴とするものである。但し、(2)式において、Ugは、搬送用ガスのランスノズル出口における流速(m/sec)、hは、上吹きランスのランス高さ(m)、Dは、上吹きランスのノズル径(m)である。   In the hot metal desulfurization method according to the third invention, the flow velocity at the lance nozzle outlet of the carrier gas supplied from the upper blowing lance is the lance height and nozzle diameter of the upper blowing lance in the first or second invention. On the other hand, the following expression (2) is satisfied. However, in the equation (2), Ug is the flow velocity (m / sec) at the lance nozzle outlet of the carrier gas, h is the lance height (m) of the upper blowing lance, and D is the nozzle diameter of the upper blowing lance ( m).
第4の発明に係る溶銑の脱硫方法は、第1ないし第3の発明の何れかにおいて、前記脱硫剤は、実質的にフッ素を含有していないことを特徴とするものである。   A hot metal desulfurization method according to a fourth invention is characterized in that, in any one of the first to third inventions, the desulfurization agent does not substantially contain fluorine.
本発明によれば、反応性に優れる細粒の脱硫剤を、溶銑トン当たり1.6kg/min以下の供給速度で、搬送用ガスとともに上吹き添加するので、添加時の飛散は少なく、脱硫剤の添加歩留まりが向上し、且つ、添加した脱硫剤同士の溶銑中における凝集が抑制される。その結果、脱硫反応が促進され、脱硫率を著しく向上させることができ、脱硫処理時間の削減及び脱硫剤原単位の削減が達成される。更に、細粒の脱硫剤は反応界面積が大きく、脱硫反応が促進されることから、フッ化カルシウムなどの滓化促進剤を使用することなく、CaOを主体とする脱硫剤のみで効率良く脱硫することが可能となる。   According to the present invention, the fine desulfurization agent having excellent reactivity is added by blowing up with the carrier gas at a supply rate of 1.6 kg / min or less per ton of molten iron, so that the desulfurization agent is less scattered at the time of addition. And the agglomeration in the hot metal between the added desulfurizing agents is suppressed. As a result, the desulfurization reaction is promoted, the desulfurization rate can be remarkably improved, and the reduction of the desulfurization treatment time and the reduction of the desulfurizing agent basic unit are achieved. Furthermore, since the fine-grained desulfurization agent has a large reaction interfacial area and promotes the desulfurization reaction, desulfurization can be efficiently performed only with a desulfurization agent mainly composed of CaO without using a hatching accelerator such as calcium fluoride. It becomes possible to do.
以下、本発明を具体的に説明する。   The present invention will be specifically described below.
機械攪拌式脱硫法において脱硫反応効率を向上させるには、脱硫剤粉体の凝集を抑制し、脱硫剤の浴内での分散を促進させることが有効である。この手段のひとつとして、上吹きランスを介して脱硫剤を連続的に溶銑浴面に向けて上吹き添加する方法が考えられる。しかし、そのときの脱硫挙動は、上吹きランスから供給される脱硫剤の供給速度や上吹きランスのランス高さなどにより種々の影響を受ける。そこで、本発明者等は、上吹きランスから溶銑浴面に向けて脱硫剤を吹き付けて行う機械攪拌式脱硫法において、脱硫挙動に及ぼす因子の影響を解明するために実験・調査を行った。尚、上吹きランスのランス高さとは、上吹きランスの先端と静止状態の溶銑浴面との距離である。   In order to improve the desulfurization reaction efficiency in the mechanical stirring type desulfurization method, it is effective to suppress the aggregation of the desulfurization agent powder and promote the dispersion of the desulfurization agent in the bath. As one of the means, a method in which a desulfurizing agent is continuously blown and added toward the hot metal bath surface through a top blowing lance can be considered. However, the desulfurization behavior at that time is affected variously by the supply speed of the desulfurizing agent supplied from the top blowing lance, the lance height of the top blowing lance, and the like. Therefore, the present inventors conducted experiments and investigations to clarify the influence of factors on the desulfurization behavior in the mechanical stirring desulfurization method in which a desulfurizing agent is sprayed from the top blowing lance toward the hot metal bath surface. The lance height of the upper blowing lance is the distance between the tip of the upper blowing lance and the hot metal bath surface in a stationary state.
図1に、機械攪拌式脱硫装置を模擬した実験装置の概略図を示す。実験装置8は高周波加熱コイル11を備えており、坩堝容器10に保持した溶銑3に攪拌羽根4を浸漬させ、電動機9により攪拌羽根4を回転させ、溶銑3の撹拌を行った。次いで、溶銑3の浴面上に設置した粉体吹き付け用上吹きランス5を介して、溶銑の回転撹拌中に搬送用の窒素ガスとともに脱硫剤の上吹き添加を行った。その際、脱硫剤の供給速度、上吹きランス5のノズル径、ランス高さなどの上吹き条件を変化させた。脱硫剤としてはCaO粉単体を使用した。また、比較のために脱硫剤を溶銑3に一括上置き添加した試験も実施した。   FIG. 1 shows a schematic diagram of an experimental apparatus simulating a mechanical stirring type desulfurization apparatus. The experimental apparatus 8 includes a high-frequency heating coil 11, and the stirring blade 4 is immersed in the hot metal 3 held in the crucible container 10, and the stirring blade 4 is rotated by the electric motor 9 to stir the hot metal 3. Subsequently, a desulfurizing agent was added by top blowing through a top blowing lance 5 for spraying powder on the bath surface of the hot metal 3 together with nitrogen gas for conveyance during the rotary stirring of the hot metal. At that time, the top blowing conditions such as the supply speed of the desulfurizing agent, the nozzle diameter of the top blowing lance 5 and the lance height were changed. As the desulfurizing agent, CaO powder alone was used. For comparison, a test was also conducted in which a desulfurizing agent was added to the hot metal 3 all at once.
先ず、上吹きランスからの脱硫剤の供給速度を変化させ、脱硫反応効率におよぼす脱硫剤供給速度の影響を調査した。尚、脱硫反応効率とは、下記の(4)式で示すように、添加したCaOのうち、溶銑中の硫黄と反応したCaOの割合(百分率)である。   First, the supply rate of the desulfurizing agent from the top blowing lance was changed, and the influence of the desulfurizing agent supply rate on the desulfurization reaction efficiency was investigated. In addition, desulfurization reaction efficiency is the ratio (percentage) of CaO which reacted with sulfur in hot metal among the added CaO, as shown by the following formula (4).
試験結果を図2に示す。上吹きランスからの脱硫剤の供給速度が、溶銑トン当たり1.6kg/min(以下「kg/min・t」と記す)以下の条件において脱硫反応効率が大きく向上し、逆に、脱硫剤の供給速度が1.6kg/min・tを超える条件において脱硫反応効率は徐々に低下した。   The test results are shown in FIG. The desulfurization reaction efficiency from the top blowing lance is greatly improved under the condition that the feed rate of the desulfurization agent is 1.6 kg / min per ton of hot metal (hereinafter referred to as “kg / min · t”) or less. The desulfurization reaction efficiency gradually decreased under conditions where the feed rate exceeded 1.6 kg / min · t.
この現象を解明するために実験後のスラグの調査並びにモデル実験を行った結果、上吹きランスからの脱硫剤の供給速度が1.6kg/min・t以下の場合には、脱硫剤が溶銑中に巻き込まれ、溶銑浴中に浸入した際に脱硫剤同士の凝集が抑制され、脱硫剤の分散が促進されることが分かった。逆に、上吹き供給速度が1.6kg/min・tを超える場合には、単位時間当たりの脱硫剤供給量が多すぎるために、凝集が進行して脱硫剤を一括上置き添加した場合と見かけ上同等であることが分かった。   As a result of investigating the slag after the experiment and conducting a model experiment to clarify this phenomenon, the desulfurization agent is in the hot metal when the supply rate of the desulfurization agent from the top blowing lance is 1.6 kg / min · t or less. It has been found that when they are caught in the hot metal bath and agglomerated in the hot metal bath, the aggregation of the desulfurizing agents is suppressed and the dispersion of the desulfurizing agents is promoted. On the contrary, when the top blowing supply rate exceeds 1.6 kg / min · t, the amount of desulfurizing agent supplied per unit time is too large, and the aggregation proceeds and the desulfurizing agent is added all at once. It turned out to be equivalent.
次に、脱硫剤の供給速度を1.6kg/min・tの一定とし、上吹きランスのノズル径(D)及び上吹きランスのランス高さ(h)を変化させて脱硫挙動を調査した。その結果を図3に示す。脱硫反応効率はランス高さ(h)とノズル径(D)との比h/Dが48.0以下の条件で向上することが分かった。つまり、上吹きランスのランス高さ(h)が上吹きランスのノズル径(D)に対して、下記の(1)式を満足する場合に脱硫反応効率が向上した。   Next, the desulfurization behavior was investigated by changing the supply speed of the desulfurizing agent to 1.6 kg / min · t and changing the nozzle diameter (D) of the upper blowing lance and the lance height (h) of the upper blowing lance. The result is shown in FIG. It was found that the desulfurization reaction efficiency was improved when the ratio h / D between the lance height (h) and the nozzle diameter (D) was 48.0 or less. That is, the desulfurization reaction efficiency was improved when the lance height (h) of the top blowing lance satisfied the following formula (1) with respect to the nozzle diameter (D) of the top blowing lance.
この理由について搬送用ガスとともに噴出する脱硫剤粒子の運動について種々検討した。その結果を図4に示す。脱硫剤粒子が溶銑浴面に到達したとき、脱硫剤粒子が溶銑に浸入する条件の臨界値が、比h/Dが48.0となる吹き込み条件であった。つまり、比h/Dが48.0を超える範囲では、ランス高さ(h)がノズル径(D)に対して相対的に大きくなりすぎ、脱硫剤粒子の溶銑浴面に衝突する際の速度が低下するためと考えられる。このことから、比h/Dの値が48.0以下の領域においては、溶銑浴面に到達した脱硫剤粒子が溶銑中に浸入し、それが回転撹拌によって溶銑中に広く分散することになる。   For this reason, various studies were made on the motion of desulfurizing agent particles ejected together with the carrier gas. The result is shown in FIG. When the desulfurizing agent particles reached the hot metal bath surface, the critical value of the conditions for the desulfurizing agent particles to enter the hot metal was the blowing condition where the ratio h / D was 48.0. That is, in the range where the ratio h / D exceeds 48.0, the lance height (h) becomes too large relative to the nozzle diameter (D), and the speed at which the desulfurizing agent particles collide with the hot metal bath surface. This is thought to be due to a decline. From this, in the region where the value of the ratio h / D is 48.0 or less, the desulfurizing agent particles that have reached the hot metal bath surface enter the hot metal and are widely dispersed in the hot metal by rotary stirring. .
更に、脱硫剤の供給速度を1.6kg/min・tの一定の条件のもと、各種ノズル径及びランス高さごとに搬送用ガス流量を変化させて脱硫挙動を調査した。その結果を図5に示す。脱硫反応効率が向上した条件では、溶銑浴面到達時の搬送用ガスの流速が10m/sec以上であることが分かった。このときのノズル径(D)及びランス高さ(h)の条件と、ノズル出口における搬送用ガスの流速(Ug)との関係を整理すると図6のようになり、ノズル出口における搬送用ガスの流速(Ug:単位m/sec)を、ランス高さ(h)とノズル径(D)との比h/Dに1.67を乗算した数値以上とすることで脱硫反応効率が向上することが分かった。つまり、上吹きランスから供給する搬送用ガスのランスノズル出口における流速(Ug)が、上吹きランスのランス高さ(h)及びノズル径(D)に対して、下記の(2)式を満足する場合に脱硫反応効率が向上した。   Further, the desulfurization behavior was investigated by changing the flow rate of the conveying gas for each nozzle diameter and lance height under a constant desulfurization agent supply rate of 1.6 kg / min · t. The result is shown in FIG. It was found that under conditions where the desulfurization reaction efficiency was improved, the flow rate of the conveying gas when reaching the hot metal bath surface was 10 m / sec or more. The relationship between the conditions of the nozzle diameter (D) and the lance height (h) at this time and the flow velocity (Ug) of the transfer gas at the nozzle outlet is as shown in FIG. Desulfurization reaction efficiency can be improved by setting the flow velocity (Ug: unit m / sec) to a value obtained by multiplying the ratio h / D between the lance height (h) and the nozzle diameter (D) by 1.67. I understood. In other words, the flow velocity (Ug) at the lance nozzle outlet of the conveying gas supplied from the upper blowing lance satisfies the following formula (2) with respect to the lance height (h) and nozzle diameter (D) of the upper blowing lance. In this case, the desulfurization reaction efficiency was improved.
この理由について上記と同様に搬送用ガスとともに噴出する脱硫剤粒子の運動について解析検討したところ、脱硫剤粒子が溶銑浴面に到達したとき、粒子が溶銑に浸入する臨界条件は、ノズル出口でのガス流速(Ug)が、ランス高さ(h)とノズル径(D)との比h/Dに1.67を乗算した数値と一致する場合であった。従って、ノズル出口でのガス流速(Ug)が(2)式の関係を満足する場合には、溶銑浴面に到達した脱硫剤粒子は溶銑中に浸入し、溶銑中に広く分散することになる。   For this reason, the analysis of the movement of the desulfurizing agent particles ejected together with the carrier gas in the same manner as described above revealed that when the desulfurizing agent particles reach the hot metal bath surface, the critical condition for the particles to enter the hot metal bath is determined at the nozzle outlet. In this case, the gas flow rate (Ug) coincided with the numerical value obtained by multiplying the ratio h / D between the lance height (h) and the nozzle diameter (D) by 1.67. Therefore, when the gas flow velocity (Ug) at the nozzle outlet satisfies the relationship of the expression (2), the desulfurizing agent particles that have reached the hot metal bath surface enter the hot metal and are widely dispersed in the hot metal. .
本発明はこれらの試験結果に基づくものであり、溶銑の機械攪拌式脱硫法において、攪拌羽根によって攪拌されている溶銑の浴面上に、脱硫剤の供給速度を1.6kg/min・t以下として、上吹きランスを介して搬送用ガスとともに脱硫剤を上吹き添加することを必須条件とする。   The present invention is based on these test results. In the hot metal mechanical stirring desulfurization method, the supply rate of the desulfurizing agent is 1.6 kg / min · t or less on the bath surface of the hot metal being stirred by the stirring blade. As a precondition, it is necessary to add the desulfurization agent by blowing up with the carrier gas through the top blowing lance.
この場合、溶銑浴面に到達した脱硫剤粒子を溶銑中に浸入させ、侵入させた脱硫剤を回転撹拌によって溶銑中に広く分散させるためには、ランス高さ(h)とノズル径(D)との関係が上記の(1)式を満足するようにランス高さ(h)及びノズル径(D)を決定し、更に、ノズル出口での搬送用ガスの流速(Ug)が、ランス高さ(h)及びノズル径(D)に対して上記の(2)式を満足するように設定することが好ましい。このようにすることで、脱硫剤粒子の溶銑浴中への浸入がより一層促進されるため、更なる脱硫反応の高効率化が期待できる。   In this case, the lance height (h) and the nozzle diameter (D) are used to allow the desulfurizing agent particles that have reached the hot metal bath surface to enter the hot metal and to disperse the invaded desulfurizing agent widely in the hot metal by rotary stirring. The lance height (h) and the nozzle diameter (D) are determined so that the relationship with the above equation (1) satisfies the above formula (1), and the flow velocity (Ug) of the transfer gas at the nozzle outlet is determined by the lance height. It is preferable to set so that said (2) Formula is satisfied with respect to (h) and a nozzle diameter (D). By doing in this way, since the penetration | invasion of the desulfurization agent particle | grains in the hot metal bath is further accelerated | stimulated, the further highly efficient desulfurization reaction can be anticipated.
ここで、上吹き添加する脱硫剤としては、CaO粉にホタル石(CaF2 )を含有させたCaO−CaF2 系脱硫剤でも構わないが、今日の環境問題を鑑みるに脱硫剤の組成としてホタル石を用いない脱硫剤を使用することが望ましい。本発明では、脱硫剤を上吹き添加するので、ホタル石などのフッ素含有物質を滓化促進剤として使用しなくても、十分に脱硫することができる。このとき、CaO粉に脱酸源を有するAl灰などと添加しても構わないが、CaO粉単体のみを適用しても十分に脱硫することができる。 Here, the desulfurizing agent added by top blowing may be a CaO—CaF 2 -based desulfurizing agent in which fluorite (CaF 2 ) is contained in CaO powder. It is desirable to use a desulfurizing agent that does not use stone. In the present invention, since the desulfurizing agent is added by top blowing, desulfurization can be sufficiently performed without using a fluorine-containing substance such as fluorite as a hatching accelerator. At this time, Al ash having a deoxidation source may be added to the CaO powder, but sufficient desulfurization can be achieved by applying only the CaO powder alone.
また、脱硫剤粉体を搬送する搬送用ガスとしては、不活性ガス、非酸化性ガス、還元性ガスの何れかの一種類以上を使用することができる。酸化性ガスは溶銑中の酸素ポテンシャルを上昇させ、脱硫に不利な条件となるため適当ではない。但し、酸化性ガスを微量に含有する不活性ガス、非酸化性ガス、還元性ガスは十分に適用可能である。   Further, as the transfer gas for transferring the desulfurizing agent powder, one or more of an inert gas, a non-oxidizing gas, and a reducing gas can be used. Oxidizing gas is not suitable because it raises the oxygen potential in the hot metal and is a disadvantageous condition for desulfurization. However, an inert gas, a non-oxidizing gas, and a reducing gas that contain a small amount of an oxidizing gas are sufficiently applicable.
本発明によれば、反応性に優れる細粒の脱硫剤を、1.6kg/min・t以下の供給速度で搬送用ガスとともに上吹き添加するので、添加時の飛散は少なく、脱硫剤の添加歩留まりが向上し、且つ、添加した脱硫剤同士の溶銑中における凝集が抑制される。その結果、脱硫反応が促進され、脱硫率を著しく向上させることができ、脱硫処理時間の削減及び脱硫剤原単位の削減が達成される。   According to the present invention, the fine desulfurization agent having excellent reactivity is added by blowing up with the carrier gas at a supply rate of 1.6 kg / min · t or less, so there is little scattering during addition, and the addition of the desulfurization agent The yield is improved, and aggregation of the added desulfurizing agents in the hot metal is suppressed. As a result, the desulfurization reaction is promoted, the desulfurization rate can be remarkably improved, and the reduction of the desulfurization treatment time and the reduction of the desulfurizing agent basic unit are achieved.
図7に示す機械攪拌式脱硫装置を用いて実施した本発明の実施例(本発明例)を比較例とともに説明する。   An example of the present invention (example of the present invention) carried out using the mechanical stirring desulfurization apparatus shown in FIG. 7 will be described together with a comparative example.
図7において、1は台車、2は溶銑鍋、3は溶銑、4は攪拌羽根、5は上吹きランス、6はディスペンサー、7は脱硫剤であり、台車1に積載された溶銑鍋2に収容された約300トンの溶銑3に攪拌羽根4を浸漬させ、軸4aを回転させながら、窒素ガスを搬送用ガスとして上吹きランス5から脱硫剤7を溶銑浴面に向けて吹き付けて脱硫処理を実施した。脱硫剤7の添加量は5.0kg/tとした。溶銑成分、攪拌羽根回転数、脱硫処理時間などの処理条件を表1に示す。   In FIG. 7, 1 is a cart, 2 is a hot metal ladle, 3 is hot metal, 4 is a stirring blade, 5 is a top lance, 6 is a dispenser, 7 is a desulfurizing agent, and is accommodated in a hot metal ladle 2 loaded on the cart 1. The desulfurization treatment is performed by immersing the stirring blade 4 in about 300 tons of the molten iron 3 and rotating the shaft 4a while blowing the desulfurizing agent 7 from the top blowing lance 5 toward the hot metal bath surface using nitrogen gas as a carrier gas. Carried out. The amount of desulfurizing agent 7 added was 5.0 kg / t. Table 1 shows processing conditions such as hot metal components, stirring blade rotation speed, and desulfurization processing time.
脱硫処理は、本発明例1〜4及び比較例1〜3の合計7水準で実施した。各脱硫処理における処理条件を表2に示す。   The desulfurization treatment was carried out at a total of 7 levels of Invention Examples 1 to 4 and Comparative Examples 1 to 3. Table 2 shows the treatment conditions in each desulfurization treatment.
本発明例1〜4では、溶銑の浴面上に上吹きランスを降下させ、回転撹拌中に搬送用ガスとともに脱硫剤の上吹き添加を行った。本発明例1では、脱硫剤としてCaO−5質量%CaF2 を使用し、脱硫剤の供給速度を1.0kg/min・tとした。ランス高さ(h)、ノズル径(D)は、それぞれ1.5m、0.03mとした。搬送用ガスの流量(Q)は2.12Nm3/minとした。このときのノズル出口でのガスの流速は50m/secである。 In Invention Examples 1 to 4, the top blowing lance was lowered on the hot metal bath surface, and the top blowing addition of the desulfurizing agent was performed together with the carrier gas during the rotary stirring. In Example 1 of the present invention, CaO-5 mass% CaF 2 was used as a desulfurization agent, and the supply rate of the desulfurization agent was 1.0 kg / min · t. The lance height (h) and nozzle diameter (D) were 1.5 m and 0.03 m, respectively. The flow rate (Q) of the carrier gas was 2.12 Nm 3 / min. At this time, the flow rate of the gas at the nozzle outlet is 50 m / sec.
本発明例2では、脱硫剤としてCaO粉単体を使用し、脱硫剤供給速度を0.5kg/min・tとした。ランス高さ(h)、ノズル径(D)及び搬送用ガス流量(Q)は本発明例1と同一であり、それぞれ1.5m、0.03m、2.12Nm3 /minとした。 In Example 2 of the present invention, CaO powder alone was used as the desulfurizing agent, and the desulfurizing agent supply rate was 0.5 kg / min · t. The lance height (h), nozzle diameter (D), and conveying gas flow rate (Q) were the same as in Example 1 of the present invention, and were 1.5 m, 0.03 m, and 2.12 Nm 3 / min, respectively.
本発明例3では、脱硫剤としてCaO粉単体を使用し、脱硫剤供給速度を0.5kg/min・tとした。ランス高さ(h)及びノズル径(D)は、比h/Dが48.0以下となるように、それぞれ1.0m、0.03mとした。搬送用ガスの流量(Q)は2.12Nm3 /minとした。 In Example 3 of the present invention, CaO powder alone was used as the desulfurizing agent, and the desulfurizing agent supply rate was 0.5 kg / min · t. The lance height (h) and nozzle diameter (D) were 1.0 m and 0.03 m, respectively, so that the ratio h / D was 48.0 or less. The flow rate (Q) of the carrier gas was 2.12 Nm 3 / min.
本発明例4では、脱硫剤としてCaO粉単体を使用し、脱硫剤供給速度を0.5kg/min・tとした。ランス高さ(h)、ノズル径(D)はそれぞれ0.7m、0.025mとした。また、搬送用ガスの流量(Q)は3.00Nm3 /minとし、このときのノズル出口でのガスの流速(Ug)は,1.67×(H/D)以上を満足する100m/secであった。 In Example 4 of the present invention, CaO powder alone was used as the desulfurizing agent, and the desulfurizing agent supply rate was 0.5 kg / min · t. The lance height (h) and nozzle diameter (D) were 0.7 m and 0.025 m, respectively. Further, the flow rate (Q) of the carrier gas is 3.00 Nm 3 / min, and the gas flow velocity (Ug) at the nozzle outlet at this time satisfies 1.67 × (H / D) or more 100 m / sec. Met.
これに対して、比較例1では、脱硫剤としてCaO−5質量%CaF2 粉体を用い、この脱硫剤を回転撹拌初期に一括して溶銑浴面上に上置き添加した。比較例2では、脱硫剤としてCaO−5質量%CaF2粉体を用いて上吹き添加を行った。脱硫剤供給速度は3.0kg/min・tとした。ランス高さ(h)、ノズル径(D)、搬送用ガスの流量(Q)は本発明例1と同様に、それぞれ1.5m、0.03m、2.12Nm3/minとした。比較例3では、脱硫剤としてCaO粉単体を使用し、上吹き添加を行った。脱硫剤供給速度は3.0kg/min・tとした。ランス高さ(h)、ノズル径(D)、搬送用ガスの流量(Q)は本発明例1と同様に、それぞれ1.5m、0.03m、2.12Nm3/minとした。本発明例及び比較例ともに処理前後のメタルサンプリングを行い、脱硫率を調査した。ここで、脱硫率は下記の(5)式で定義される値とした。 On the other hand, in Comparative Example 1, CaO-5 mass% CaF 2 powder was used as a desulfurizing agent, and this desulfurizing agent was added on the hot metal bath surface all together at the initial stage of rotary stirring. In Comparative Example 2, the top blowing addition was performed using CaO-5 mass% CaF 2 powder as a desulfurization agent. The desulfurization agent supply rate was 3.0 kg / min · t. The lance height (h), the nozzle diameter (D), and the flow rate (Q) of the carrier gas were set to 1.5 m, 0.03 m, and 2.12 Nm 3 / min, respectively, as in Example 1 of the present invention. In Comparative Example 3, CaO powder alone was used as a desulfurization agent, and top blowing was performed. The desulfurization agent supply rate was 3.0 kg / min · t. The lance height (h), the nozzle diameter (D), and the flow rate (Q) of the carrier gas were set to 1.5 m, 0.03 m, and 2.12 Nm 3 / min, respectively, as in Example 1 of the present invention. Both the present invention example and the comparative example were subjected to metal sampling before and after the treatment to investigate the desulfurization rate. Here, the desulfurization rate was a value defined by the following equation (5).
また、処理後にスラグを回収して、スラグ粒径も調査した。実施結果を表3に示す。   Moreover, slag was collect | recovered after the process and the slag particle size was also investigated. The results are shown in Table 3.
脱硫剤がCaO−5質量%CaF2 粉体である本発明例1、比較例1及び比較例2を対比すると、脱硫剤の供給速度を1.6kg/min・t以下とした本発明例1の方が脱硫率が向上し、処理後のスラグ粒径も小さくなっていた。脱硫剤がCaO単体である本発明例2と比較例3とを対比しても、同様に本発明例2の方が脱硫率が向上し、処理後のスラグ粒径も小さくなっていた。 When the present invention example 1, comparative example 1 and comparative example 2 in which the desulfurizing agent is CaO-5 mass% CaF 2 powder are compared, the desulfurizing agent supply rate is 1.6 kg / min · t or less of the present invention example 1. This improved the desulfurization rate, and the slag particle size after the treatment was also small. Even if the present invention example 2 in which the desulfurizing agent is CaO alone is compared with the comparative example 3, the present invention example 2 also has a higher desulfurization rate and a smaller slag particle size after the treatment.
また、ランス高さ(h)とノズル径(D)の比h/Dの値が48.0以下である本発明例3は、本発明例2と比較すると溶銑浴中への脱硫剤粒子の浸入が改善されるので、本発明例2よりも脱硫率が向上した。更に、ノズル出口でのガスの流速が1.67×h/D以上を満足する100m/secとなるように調整した本発明例4は、本発明例3と比較して更に脱硫率が向上し、処理後のスラグ粒径もさらに小さくなった。   In addition, the present invention example 3 in which the ratio h / D ratio of the lance height (h) to the nozzle diameter (D) is 48.0 or less is higher in the desulfurization agent particles in the hot metal bath than in the present invention example 2. Since the infiltration was improved, the desulfurization rate was improved as compared with Invention Example 2. Furthermore, Example 4 of the present invention, which was adjusted so that the gas flow rate at the nozzle outlet was 100 m / sec satisfying 1.67 × h / D or more, further improved the desulfurization rate compared to Example 3 of the present invention. The slag particle size after the treatment was further reduced.
機械攪拌式脱硫装置を模擬した実験装置の概略図である。It is the schematic of the experimental apparatus which simulated the mechanical stirring desulfurization apparatus. 脱硫剤供給速度と脱硫反応効率との関係を示す図である。It is a figure which shows the relationship between a desulfurization agent supply rate and desulfurization reaction efficiency. h/Dと脱硫反応効率との関係を示す図である。It is a figure which shows the relationship between h / D and desulfurization reaction efficiency. 脱硫剤粒子が溶銑中に浸入する臨界値を示す図である。It is a figure which shows the critical value in which a desulfurization agent particle | grain penetrates into hot metal. 浴面到達時の搬送用ガス流速と脱硫反応効率との関係を示す図である。It is a figure which shows the relationship between the gas flow rate for conveyance at the time of bath surface arrival, and desulfurization reaction efficiency. ノズル出口における搬送用ガスの流速(Ug)とh/Dとの関係から脱硫反応効率の良好な領域を示す図である。It is a figure which shows the area | region where the desulfurization reaction efficiency is favorable from the relationship between the flow velocity (Ug) of the gas for conveyance in a nozzle exit, and h / D. 実施例において使用した機械攪拌式脱硫装置の概略図である。It is the schematic of the mechanical stirring desulfurization apparatus used in the Example.
符号の説明Explanation of symbols
1 台車
2 溶銑鍋
3 溶銑
4 攪拌羽根
5 上吹きランス
6 ディスペンサー
7 脱硫剤
8 実験装置
9 電動機
10 坩堝容器
11 高周波加熱コイル
1 cart 2 hot metal ladle 3 hot metal 4 stirring blade 5 top blowing lance 6 dispenser 7 desulfurizing agent 8 experimental device 9 electric motor 10 crucible container 11 high frequency heating coil

Claims (4)

  1. 機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、溶銑トン当たり1.6kg/min以下の脱硫剤の供給速度で、上吹きランスを介して搬送用ガスとともに脱硫剤を上吹き添加して脱硫することを特徴とする、溶銑の脱硫方法。   In the hot metal desulfurization method using the mechanical stirring type desulfurization apparatus, the hot metal is being stirred by the stirring blades, and the hot metal bath surface is fed with a desulfurizing agent at a rate of 1.6 kg / min or less per ton of hot metal, through an upper blowing lance. A hot metal desulfurization method, wherein a desulfurization agent is blown up and desulfurized together with a carrier gas.
  2. 前記上吹きランスのランス高さが、該上吹きランスのノズル径に対して、下記の(1)式を満足することを特徴とする、請求項1に記載の溶銑の脱硫方法。
    h≦48.0×D …(1)
    但し、(1)式において、hは、上吹きランスのランス高さ(m)、Dは、上吹きランスのノズル径(m)である。
    2. The hot metal desulfurization method according to claim 1, wherein a lance height of the upper blowing lance satisfies the following expression (1) with respect to a nozzle diameter of the upper blowing lance.
    h ≦ 48.0 × D (1)
    However, in Formula (1), h is the lance height (m) of the upper blowing lance, and D is the nozzle diameter (m) of the upper blowing lance.
  3. 前記上吹きランスから供給する搬送用ガスのランスノズル出口における流速が、該上吹きランスのランス高さ及びノズル径に対して、下記の(2)式を満足することを特徴とする、請求項1または請求項2に記載の溶銑の脱硫方法。
    Ug≧1.67×(h/D) …(2)
    但し、(2)式において、Ugは、搬送用ガスのランスノズル出口における流速(m/sec)、hは、上吹きランスのランス高さ(m)、Dは、上吹きランスのノズル径(m)である。
    The flow rate at the lance nozzle outlet of the conveying gas supplied from the upper blowing lance satisfies the following expression (2) with respect to the lance height and nozzle diameter of the upper blowing lance. The hot metal desulfurization method according to claim 1 or 2.
    Ug ≧ 1.67 × (h / D)… (2)
    However, in the equation (2), Ug is the flow velocity (m / sec) at the lance nozzle outlet of the carrier gas, h is the lance height (m) of the upper blowing lance, and D is the nozzle diameter of the upper blowing lance ( m).
  4. 前記脱硫剤は、実質的にフッ素を含有していないことを特徴とする、請求項1ないし請求項3の何れか1つに記載の溶銑の脱硫方法。   The hot metal desulfurization method according to any one of claims 1 to 3, wherein the desulfurization agent does not substantially contain fluorine.
JP2006076243A 2006-03-20 2006-03-20 Hot metal desulfurization method Active JP4961787B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006076243A JP4961787B2 (en) 2006-03-20 2006-03-20 Hot metal desulfurization method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006076243A JP4961787B2 (en) 2006-03-20 2006-03-20 Hot metal desulfurization method

Publications (2)

Publication Number Publication Date
JP2007247045A true JP2007247045A (en) 2007-09-27
JP4961787B2 JP4961787B2 (en) 2012-06-27

Family

ID=38591659

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006076243A Active JP4961787B2 (en) 2006-03-20 2006-03-20 Hot metal desulfurization method

Country Status (1)

Country Link
JP (1) JP4961787B2 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008184684A (en) * 2007-01-31 2008-08-14 Jfe Steel Kk Method of desulfurizing molten pig iron
JP2009191288A (en) * 2008-02-12 2009-08-27 Jfe Steel Corp Apparatus and method for supplying desulfurizing agent into molten iron
JP2011006761A (en) * 2009-06-29 2011-01-13 Jfe Steel Corp Method for desulfurizing molten iron
JP2011042815A (en) * 2009-08-19 2011-03-03 Jfe Steel Corp Method for desulfurizing molten iron
EP3327150A4 (en) * 2015-07-24 2018-05-30 JFE Steel Corporation Desulfurizing agent, method for desulfurizing molten iron and method for producing molten iron

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60162717A (en) * 1984-02-04 1985-08-24 Nippon Kokan Kk <Nkk> Treatment of molten iron
JPS63210225A (en) * 1987-02-26 1988-08-31 Nippon Steel Corp Equipment for pretreating molten pig iron in casting bed
JP2000096115A (en) * 1998-09-21 2000-04-04 Sumitomo Metal Ind Ltd Method for killing slag foaming
JP2003119509A (en) * 2001-10-11 2003-04-23 Nippon Steel Corp Method for pretreating pig iron, and impeller device
JP2005146335A (en) * 2003-11-14 2005-06-09 Jfe Steel Kk Method for dephosphorizing molten pig iron
JP2005179690A (en) * 2003-12-16 2005-07-07 Jfe Steel Kk Method for desulfurizing molten pig iron
JP2006028615A (en) * 2004-07-20 2006-02-02 Sumitomo Metal Ind Ltd Method for desulfurizing molten pig iron, and mechanically stirring device
JP2006291334A (en) * 2005-04-14 2006-10-26 Sumitomo Metal Ind Ltd Method for recycling dust at pretreatment of molten iron

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60162717A (en) * 1984-02-04 1985-08-24 Nippon Kokan Kk <Nkk> Treatment of molten iron
JPS63210225A (en) * 1987-02-26 1988-08-31 Nippon Steel Corp Equipment for pretreating molten pig iron in casting bed
JP2000096115A (en) * 1998-09-21 2000-04-04 Sumitomo Metal Ind Ltd Method for killing slag foaming
JP2003119509A (en) * 2001-10-11 2003-04-23 Nippon Steel Corp Method for pretreating pig iron, and impeller device
JP2005146335A (en) * 2003-11-14 2005-06-09 Jfe Steel Kk Method for dephosphorizing molten pig iron
JP2005179690A (en) * 2003-12-16 2005-07-07 Jfe Steel Kk Method for desulfurizing molten pig iron
JP2006028615A (en) * 2004-07-20 2006-02-02 Sumitomo Metal Ind Ltd Method for desulfurizing molten pig iron, and mechanically stirring device
JP2006291334A (en) * 2005-04-14 2006-10-26 Sumitomo Metal Ind Ltd Method for recycling dust at pretreatment of molten iron

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008184684A (en) * 2007-01-31 2008-08-14 Jfe Steel Kk Method of desulfurizing molten pig iron
JP2009191288A (en) * 2008-02-12 2009-08-27 Jfe Steel Corp Apparatus and method for supplying desulfurizing agent into molten iron
JP2011006761A (en) * 2009-06-29 2011-01-13 Jfe Steel Corp Method for desulfurizing molten iron
JP2011042815A (en) * 2009-08-19 2011-03-03 Jfe Steel Corp Method for desulfurizing molten iron
EP3327150A4 (en) * 2015-07-24 2018-05-30 JFE Steel Corporation Desulfurizing agent, method for desulfurizing molten iron and method for producing molten iron

Also Published As

Publication number Publication date
JP4961787B2 (en) 2012-06-27

Similar Documents

Publication Publication Date Title
JP4845078B2 (en) Hot metal desulfurization method
JP5194678B2 (en) Hot metal desulfurization method
KR20030040463A (en) Refining agent and refining method
KR101366720B1 (en) Method of desulfurization of molten iron
JP4961787B2 (en) Hot metal desulfurization method
JP2008050659A (en) Desulfurizing agent for molten iron and method for desulfurization treatment
JP5195737B2 (en) Hot metal desulfurization method
JP4715369B2 (en) Hot metal desulfurization treatment method
JP5177170B2 (en) Hot metal desulfurization method
JP4635672B2 (en) Method for refining molten metal
JP5130663B2 (en) Method for refining molten iron
JP5074063B2 (en) Desulfurization agent and method for desulfurization of molten iron
JP5341235B2 (en) Desulfurization agent and method for desulfurization of molten iron
JP5458499B2 (en) Hot metal desulfurization treatment method
JP5446300B2 (en) Hot metal desulfurization treatment method
JP5790230B2 (en) Hot metal desulfurization method
JP5401938B2 (en) Hot metal desulfurization method
JP2015218390A (en) Desulfurization method of molten pig iron using combination of mechanical stirring and gas stirring
JP2009221559A (en) Impeller for mechanical-stirring type desulfurizing apparatus
JP2016132790A (en) Desilication and desulfurization method in hot metal ladle
JP5668641B2 (en) Hot metal desulfurization method
JP6238019B2 (en) Hot metal desulfurization method with less recuperation
JP6848437B2 (en) Desulfurization method and desulfurization equipment for molten steel
JP2018172719A (en) Desulfurization method of molten pig iron
TWI564396B (en) Method of preventing backwashing of molten iron after desulfurization

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20090216

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20110818

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110927

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20111122

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20120228

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20120312

R150 Certificate of patent or registration of utility model

Ref document number: 4961787

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20150406

Year of fee payment: 3

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250