JP2001279316A - Method for pre-treating molten iron - Google Patents
Method for pre-treating molten ironInfo
- Publication number
- JP2001279316A JP2001279316A JP2000093564A JP2000093564A JP2001279316A JP 2001279316 A JP2001279316 A JP 2001279316A JP 2000093564 A JP2000093564 A JP 2000093564A JP 2000093564 A JP2000093564 A JP 2000093564A JP 2001279316 A JP2001279316 A JP 2001279316A
- Authority
- JP
- Japan
- Prior art keywords
- hot metal
- slag
- fluorine
- fluorite
- desulfurization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、溶銑の予備処理方
法に係わり、特に、製鋼炉へ装入する前の溶銑から予め
燐（Ｐ）、珪素（Ｓｉ）、硫黄（Ｓ）を除去するプロセ
ス（これらを溶銑予備処理という）において、発生する
スラグ中の弗素（Ｆ）量を低減し、その後に該スラグを
建材、路盤材等で利用する際、土壌（環境）へ弗素を溶
出させないようにする技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for pretreating hot metal, and more particularly to a process for removing phosphorus (P), silicon (Si), and sulfur (S) from hot metal before being charged into a steelmaking furnace. In these (these are called hot metal pretreatment), the amount of fluorine (F) in the generated slag is reduced, and when the slag is subsequently used in building materials, roadbed materials, etc., the fluorine is not eluted into the soil (environment). Related to technology.
【０００２】[0002]
【従来の技術】近年の製鋼工程では、発生スラグ量の低
減のため、製鋼炉へ装入する前に溶銑中の燐、硫黄、珪
素を予め除去する所謂「溶銑予備処理」が普及してい
る。2. Description of the Related Art In recent steelmaking processes, so-called "hot metal pretreatment" for preliminarily removing phosphorus, sulfur and silicon in hot metal before charging into a steelmaking furnace has been popularized in order to reduce the amount of generated slag. .
【０００３】その際、脱燐及び脱珪は、酸化反応である
ので、トピードカーに保持した溶銑に脱燐剤として粉状
の酸化鉄，ＣａＯや酸素ガスをランスを介してキャリア
ガスで吹き込むトピード型処理、あるいは転炉に保持し
た溶銑に、脱燐剤としてのＣａＯを添加すると共に、上
吹きで酸素ガスを吹き込む転炉型処理を主体としてい
る。At this time, since dephosphorization and desiliconization are oxidation reactions, a topido type in which powdered iron oxide, CaO or oxygen gas is blown into a hot metal held in a topped car as a dephosphorizing agent with a carrier gas through a lance. The process is mainly a converter type process in which CaO as a dephosphorizing agent is added to hot metal held in a converter and oxygen gas is blown in by upward blowing.
【０００４】一方、脱硫は、トピードカーに保持した溶
銑に、粉状のＣａＯ、ソーダ灰を吹き込んだり、取鍋内
の溶銑に脱硫剤を投入し、機械攪拌する方法が主体であ
る。なお、最近は、該脱硫剤にＭｇが利用されるように
なっている。[0004] On the other hand, desulfurization is mainly performed by blowing powdered CaO or soda ash into hot metal held in a topped car, or by adding a desulfurizing agent to hot metal in a ladle and mechanically stirring the hot metal. In recent years, Mg has been used as the desulfurizing agent.
【０００５】従来、かかる溶銑予備処理においては、添
加する脱燐剤、脱硫剤等の融点を低下させるため、それ
らに蛍石が添加されている。しかしながら、近年、環境
問題が重視され、製鉄所が排出するスラグの再利用に際
して、該スラグから土壌への弗素溶出量の規制が叫ばれ
るようになった。そこで、脱燐剤、脱珪剤及び脱硫剤
（以下、総称として精錬剤ということあり）の精錬能を
減少させることなく、蛍石の使用量を低減させる技術が
盛んに研究され、開示されているものも多い。Conventionally, in such hot metal pretreatment, fluorite has been added to the dephosphorizing agent, desulfurizing agent and the like to lower the melting point. However, in recent years, environmental issues have been emphasized, and when slag discharged from steelworks is reused, regulations on the amount of fluorine eluted from the slag to soil have come to be called out. Therefore, techniques for reducing the amount of fluorite used without reducing the refining ability of a dephosphorizing agent, a desiliconizing agent, and a desulfurizing agent (hereinafter, may be collectively referred to as a refining agent) have been actively studied and disclosed. There are many things.
【０００６】例えば、特開平１１−２６９５２４号公報
は、前記した転炉型の溶銑脱燐処理において、底吹きガ
ス攪拌を行ない、目標のスラグ組成を限定し、添加する
蛍石の原単位を１ｋｇ／ｔ以下に低減する技術を開示し
ている。また、特開平１１−２６９５２２号公報は、ス
ラグ中のＴ．Ｆｅ、Ａｌ2Ｏ3、ＳｉＯ2濃度を限定し
て、蛍石の添加無しで脱燐する条件を開示している。さ
らに、特開平２−１９４０８号公報に開示されているよ
うに、蛍石の代替としてＡｌ2Ｏ3（具体的には、Ａｌ2
Ｏ3又はＡｌ灰のような（Ａｌ＋Ａｌ2Ｏ3））を脱硫剤
中に混合する方法も、以前より検討されている。この蛍
石をＡｌ2Ｏ3で代替し、蛍石と同程度に精錬剤の融点を
低下させる技術は、脱燐処理では採用可能であるが、脱
硫処理では反応速度が大きく減少する旨の報告がある
（鉄と鋼：第７５年（１９８９）、１号、６６〜７３
頁）。For example, Japanese Patent Application Laid-Open No. H11-269524 discloses that in the converter type hot metal dephosphorization treatment described above, bottom blow gas agitation is performed, the target slag composition is limited, and the basic unit of fluorite to be added is 1 kg. / T is disclosed. Also, Japanese Patent Application Laid-Open No. 11-269522 discloses that T.A. It discloses conditions for dephosphorizing without adding fluorite by limiting the concentrations of Fe, Al 2 O 3 and SiO 2 . Further, as disclosed in JP-A-2-19408, the Al 2 O 3 (specifically as an alternative to fluorite, Al 2
A method of mixing (Al + Al 2 O 3 ) such as O 3 or Al ash in a desulfurizing agent has been studied for some time. The technology that replaces this fluorite with Al 2 O 3 and lowers the melting point of the refining agent to the same extent as fluorite can be used in dephosphorization, but reports that the reaction rate is greatly reduced in desulfurization. (Iron and steel: 75th year (1989), No. 1, 66-73)
page).
【０００７】一方、溶銑の脱硫処理では、通常、ＣａＯ
系、Ｎａ2Ｏ系、Ｍｇ系の脱硫剤が用いられるが、スラ
グの後処理や処理コストの観点からＣａＯ系での処理が
望ましく、ＣａＯ系脱硫剤を用いての脱硫効率向上技術
の出現が期待されている。ＣａＯ系脱硫剤で脱硫を行な
う場合、ＣａＯの融点が２０００℃以上と高く、媒溶剤
である蛍石の反応促進効果は、同じ融点降下作用のある
Ａｌ2Ｏ3に比べて大きいので、脱硫剤から蛍石を単純に
減少させるのは、脱硫剤使用量の増加に繋がり、強いて
はスラグ発生量増加を招き、好ましくない。そこで、別
の手段で脱硫効率を高める技術が提案されている。On the other hand, in desulfurization treatment of hot metal, usually, CaO
System, Na 2 O-based, and Mg-based desulfurizing agents are used. However, from the viewpoint of slag post-treatment and treatment cost, CaO-based treatment is desirable, and the emergence of desulfurization efficiency improvement technology using CaO-based desulfurizing agents is emerging. Expected. When performing desulfurization with a CaO-based desulfurizing agent, the melting point of CaO is as high as 2000 ° C. or higher, and the reaction promoting effect of fluorite, which is a medium solvent, is greater than that of Al 2 O 3 having the same melting point lowering action. Simply reducing the amount of fluorite leads to an increase in the amount of desulfurizing agent used, which in turn causes an increase in the amount of slag generated, which is not preferable. Therefore, a technique for increasing the desulfurization efficiency by another means has been proposed.
【０００８】例えば、特公平５−４３７６３号公報は、
脱硫反応が還元反応であることに着眼して、還元性ガス
を利用した脱硫促進技術を開示している。この技術は、
ＣａＯ系脱硫剤の吹き込みに用いるキャリアガスを水素
ガスとすれば、不活性ガスのキヤリアガスに比べて脱硫
が促進されるとしている。また、該公報は、比較例とし
て同じく還元性を有する炭化水素系ガスの試用を試み、
吹き込んだ際に炭化水素系ガスの分解吸熱による溶銑の
温度が低下するので、高温ほど有利な脱硫反応に対して
不利である旨、記載している。その他、特公昭６３−１
９５６２号公報に開示されたように、高炉の出銑樋の流
れに対して上方から脱硫剤を添加、下方から炭化水素系
ガス吹き込み、溶銑の脱硫を促進する技術や、特開昭６
０−２６６０７号公報、特公昭５７−４３６０８号公報
に開示されたＣａＯ系脱硫剤に石炭系炭化水素を３〜２
０質量％含む有機物質を混合する技術もある。また、特
開平１０−３１７０７０号公報は、弗素含有スラグを、
高炉で用いる焼結鉱の原料として再利用する方法を提案
している。該技術は、ＣａＯ＝６〜１２ｗｔ％の焼結鉱
を製造するにあたり、Ｔ．Ｆｅが５〜１５ｗｔ％、Ｆが
０．１〜５ｗｔ％の製鋼スラグを焼結原料に混合すると
共に、そのスラグの混合量を、高炉操業で生じるスラグ
の流動性を確保するために、その弗素含有量を３０００
〜４０００ｐｐｍになるように調整するものである。For example, Japanese Patent Publication No. 5-43763 discloses that
Focusing on the fact that the desulfurization reaction is a reduction reaction, it discloses a desulfurization acceleration technology using a reducing gas. This technology is
It is stated that if hydrogen gas is used as the carrier gas for blowing the CaO-based desulfurizing agent, desulfurization is promoted as compared with the inert gas carrier gas. The publication also attempted to use a hydrocarbon gas having a reducing property as a comparative example,
The document states that the higher the temperature, the lower the temperature of the hot metal due to the decomposition endotherm of the hydrocarbon-based gas when blown, so that a higher temperature is disadvantageous to an advantageous desulfurization reaction. In addition, Tokiko Sho 63-1
As disclosed in Japanese Patent No. 9562, a desulfurizing agent is added to the flow of a tapping gutter of a blast furnace from above and a hydrocarbon gas is blown from below to promote desulfurization of hot metal.
0-26607 and Japanese Patent Publication No. 57-43608 discloses a CaO-based desulfurizing agent containing 3 to 2 coal-based hydrocarbons.
There is also a technique of mixing an organic substance containing 0% by mass. Further, Japanese Patent Application Laid-Open No. Hei 10-31070 discloses that a fluorine-containing slag is
We have proposed a method for reusing sinter used in blast furnaces. This technique is used for producing a sintered ore of CaO = 6 to 12 wt%. A steelmaking slag having Fe of 5 to 15 wt% and F of 0.1 to 5 wt% is mixed with the sintering raw material, and the mixing amount of the slag is adjusted to ensure the fluidity of the slag generated in the blast furnace operation. 3000 content
It is adjusted to be に な る 4000 ppm.
【０００９】[0009]
【発明が解決しようとする課題】しかしながら、特開平
１１−２６９５２４公報記載の技術では、転炉型の溶銑
脱燐処理において、底吹きガス攪拌、スラグ組成を限定
しても、完全に蛍石原単位をゼロにできない。また、特
開平１１−２６９５２２号公報記載のようにスラグ組成
を限定することは、多種のプロセスや装置が存在する脱
燐処理では実施が困難である。一方、脱硫に関して、従
来知見のように融点降下が蛍石と同等になるようにＡｌ
2Ｏ3を使用しても、脱硫反応効率は低下し、発生するス
ラグ量が増加する。還元性を強くして脱硫反応を促進す
る場合でも、特公平５−４３７６３号公報記載の技術
は、脱硫剤を吹込むキャリアガスを全て水素ガスにする
ので、吹込みランスの溶損、脱硫剤の詰まり等のトラブ
ルがあると、爆発の危険性があり、実用上問題がある。
また、特公昭６３−１９５６２号公報記載の技術では、
脱硫剤の添加と炭化水素系ガスの吹き込み位置が異なる
場合、脱硫剤とガスとが十分混合しない。さらに、特開
昭６０−２６６０７号公報に記載されたような有機物の
混合は、コスト的に高価であるという問題点がある。加
えて、特開平１０−３１７０７０号公報では、製鋼スラ
グを焼結工程へリサイクルするにあたり、その配合量を
定めているが、その技術は、そもそも高炉スラグ中の弗
素含有量を高めることを目的としており、生成する高炉
スラグ中の弗素は３０００〜４０００ｐｐｍと高く、ス
ラグの流動性確保が狙いである。また、製鋼での弗素使
用については何ら言及されていない。However, in the technique described in Japanese Patent Application Laid-Open No. H11-269524, in the converter type hot metal dephosphorization treatment, even if the bottom blown gas stirring and the slag composition are limited, the fluorite basic unit is completely reduced. Cannot be zero. Further, it is difficult to limit the slag composition as described in JP-A-11-269522 in a dephosphorization treatment in which various processes and apparatuses exist. On the other hand, with regard to desulfurization, Al has to be reduced so that melting point drop is equivalent to
Even if 2 O 3 is used, the efficiency of the desulfurization reaction decreases and the amount of slag generated increases. Even in the case where the desulfurization reaction is promoted by strengthening the reducing property, the technique described in Japanese Patent Publication No. 5-43763 uses the hydrogen gas as the carrier gas for blowing the desulfurizing agent. If there is a trouble such as clogging, there is a risk of explosion, and there is a practical problem.
In the technology described in JP-B-63-19562,
When the addition of the desulfurizing agent is different from the position at which the hydrocarbon gas is blown, the desulfurizing agent and the gas are not sufficiently mixed. Further, there is a problem that the mixing of organic substances as described in JP-A-60-26607 is expensive in terms of cost. In addition, in Japanese Patent Application Laid-Open No. Hei 10-31707, the amount of steelmaking slag is determined when recycling steelmaking slag to the sintering process. However, this technique aims to increase the fluorine content in blast furnace slag in the first place. The blast furnace slag produced has a high fluorine content of 3000 to 4000 ppm, and the aim is to ensure the fluidity of the slag. No mention is made of the use of fluorine in steelmaking.
【００１０】本発明は、かかる事情に鑑み、製鉄所が発
生する総てのスラグの弗素含有量を低減すると共に、希
釈させて無害化可能な溶銑予備処理方法を提供すること
を目的としている。[0010] In view of such circumstances, an object of the present invention is to provide a hot metal pretreatment method capable of reducing the fluorine content of all slag generated in an ironworks and diluting it to make it harmless.
【００１１】[0011]
【課題を解決するための手段】まず、発明者は、上記目
的を達成するため、溶銑の脱燐及び脱硫において精錬剤
に加える蛍石の量を低減させるための実験を行った。そ
の結果、トピードカーで脱燐剤を吹込む現在の脱燐処理
では、蛍石の代替としてＡｌ2Ｏ3を使用しても、脱燐剤
ので精錬能が同等であることを見い出した。また、Ａｌ
2Ｏ3の使用についても耐火物等の問題がないことを確認
した。一方、脱硫処理については、いかなる現存のプロ
セスを用いても、蛍石無しでは脱硫効率を所望の高さに
することができないことを知った。つまり、蛍石の使用
を完全に停止することは難しい。そこで、発明者は、必
要最低限の蛍石の使用で、製鉄所発生スラグの弗素の無
害化について鋭意考察し、脱燐については、蛍石を使用
せずにできるだけ反応効率の高いプロセスを選択すると
共に、脱硫については、蛍石を使用しても、発生した弗
素含有スラグを製鉄所内の適切な工程で無害化できれば
すれば良いと考えた。つまり、製鉄所全体で対処すると
いう総合的な観点から問題を検討すべきと考えて鋭意研
究を重ね、その成果を本発明に具現化したのである。First, in order to achieve the above object, the inventor conducted an experiment for reducing the amount of fluorite added to the refining agent in dephosphorization and desulfurization of hot metal. As a result, it has been found that in the current dephosphorization treatment in which a dephosphorizing agent is blown with a topped car, even if Al 2 O 3 is used as a substitute for fluorite, the refining performance is equivalent because of the dephosphorizing agent. Also, Al
It was confirmed that there was no problem with the use of 2 O 3 such as refractories. On the other hand, as for the desulfurization treatment, it has been found that the desulfurization efficiency cannot be attained to a desired level without fluorite even if any existing process is used. In other words, it is difficult to completely stop using fluorite. Therefore, the inventor diligently considered the detoxification of fluorine in slag generated at steelworks with the use of the minimum required fluorite, and selected a process with the highest possible reaction efficiency without using fluorite for dephosphorization. At the same time, with regard to desulfurization, even if fluorite was used, it was thought that the generated fluorine-containing slag could be detoxified by an appropriate process in a steel mill. In other words, they thought that the problem should be examined from the comprehensive viewpoint of dealing with the entire steelworks, and conducted intensive research, and realized the results in the present invention.
【００１２】すなわち、本発明は、溶銑を製鋼炉へ装入
する前に、該溶銑が含有する珪素、燐、硫黄を予め除去
する溶銑予備処理において、トピードカーに保持した前
記溶銑に、蛍石を含まない精錬剤をランスを介してキャ
リアガスで吹き込み脱珪及び脱燐した後、その脱珪及び
脱燐された溶銑を取鍋に移し、蛍石を含む脱硫剤を添加
して機械撹拌して脱硫すると共に、該脱硫で生じた弗素
含有スラグを高炉装入原料の一部として使用し、該弗素
含有スラグの弗素を希釈し、弗素含有量１０００質量ｐ
ｐｍ以下の高炉スラグとして高炉から排出することを特
徴とする溶銑の予備処理方法である。That is, the present invention provides a hot metal pretreatment for removing silicon, phosphorus, and sulfur contained in the hot metal before charging the hot metal into a steelmaking furnace, by adding fluorite to the hot metal held in a topped car. After the refining agent not containing is blown with a carrier gas through a lance and desiliconized and dephosphorized, the desiliconized and dephosphorized hot metal is transferred to a ladle, and a desulfurizing agent containing fluorite is added and mechanically stirred. In addition to desulfurization, the fluorine-containing slag generated by the desulfurization is used as a part of the blast furnace feed material, and the fluorine of the fluorine-containing slag is diluted to obtain a fluorine content of 1000 mass p.
This is a pretreatment method for hot metal, which is discharged from a blast furnace as blast furnace slag of not more than pm.
【００１３】また、本発明は、前記機械撹拌中の溶銑
に、炭化水素系ガスを吹込むあるいは、炭化水素を含む
有機物質を添加することを特徴とする溶銑の予備処理方
法である。[0013] The present invention is also a method for pretreating hot metal, wherein a hydrocarbon-based gas is blown into the hot metal under mechanical stirring or an organic substance containing hydrocarbon is added.
【００１４】本発明では、脱燐剤の反応効率が高いトピ
ード型脱燐及び脱珪で蛍石レス操業を実現し、脱硫で
は、脱硫剤の反応効率の高い機械攪拌方式を選択した上
でさらに炭化水素等の利用で、蛍石ミニマムの操業を実
現するようにし、最後に、発生したスラグを高炉にリサ
イクルして弗素を希釈するようにしたので、製鉄所の全
発生スラグから土壌への弗素溶出が防止できるようにな
る。In the present invention, a fluorite-less operation is realized by a topped dephosphorization and desiliconization having a high reaction efficiency of a dephosphorizing agent. In desulfurization, a mechanical stirring system having a high reaction efficiency of a desulfurizing agent is selected. The use of hydrocarbons, etc. enabled the operation of the fluorite minimum, and finally, the slag generated was recycled to the blast furnace to dilute the fluorine. Elution can be prevented.
【００１５】[0015]
【発明の実施の形態】以下、発明をなすに至った経緯を
交え、本発明の実施の形態を説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the circumstances leading to the invention.
【００１６】発明者は、前記した製鉄所全体で対処する
という総合的な観点に立って、溶銑の予備処理を高い脱
燐効率と脱硫効率で行ない、発生させたスラグが製鉄所
外に出る際に、スラグからの弗素の土壌への溶出を著し
く低減させることに着眼した。そのため、最初に溶銑の
脱燐、脱珪を検討した後、脱硫及びその発生スラグの処
理を順次検討した。The inventor of the present invention performs a pretreatment of hot metal with a high dephosphorization efficiency and a high desulfurization efficiency from the comprehensive viewpoint of coping with the entire steelworks described above, and when the generated slag goes out of the steelworks. In particular, the present inventors focused on remarkably reducing the elution of fluorine from slag into soil. Therefore, after studying dephosphorization and desiliconization of hot metal first, desulfurization and treatment of the generated slag were examined sequentially.
【００１７】まず、溶銑の脱燐反応及び脱珪反応は、
（１）式及び（１）’式のように示される。First, the dephosphorization reaction and the desiliconization reaction of hot metal include:
Equations (1) and (1) ′ are shown.
【００１８】 ２［Ｐ］＋２．５Ｏ2＋３ＣａＯ＝３ＣａＯ・Ｐ2Ｏ5 （１） ［Ｓｉ］＋Ｏ2 ＝ＳｉＯ2 （１）’ これらの反応は、酸化反応であり、脱燐の場合、反応生
成物である燐酸は、ＣａＯにトラップされてスラグ中に
固定される。従来から脱燐においては、蛍石はＣａＯの
溶融を促進するため、脱燐反応をも促進すると言われて
いる。また、この反応は、発熱反応であり、低温ほど脱
燐が促進される。本発明では、トピード型脱燐処理を採
用することにしたが、その理由は、以下の通りである。
一方、脱珪反応では、ＣａＯとの反応によらず、蛍石の
影響は少ない。2 [P] + 2.5O 2 + 3CaO = 3CaO · P 2 O 5 (1) [Si] + O 2 = SiO 2 (1) ′ These reactions are oxidation reactions. The product phosphoric acid is trapped by CaO and fixed in the slag. Conventionally, in dephosphorization, it is said that fluorite promotes the melting of CaO and thus also promotes the dephosphorization reaction. Further, this reaction is an exothermic reaction, and the lower the temperature, the more the dephosphorization is promoted. In the present invention, a topido-type dephosphorization treatment is adopted, for the following reason.
On the other hand, in the desiliconization reaction, the influence of fluorite is small irrespective of the reaction with CaO.
【００１９】トピード型脱燐処理では、溶銑中に専用ラ
ンスを浸漬し、それを介してキャリアガスで酸化鉄、Ｃ
ａＯ、ＣａＦ2等を吹き込む。キャリアガスとしては、
Ｎ2、Ｏ2等が用いられる。燐を酸化するメインの酸素源
は、酸化鉄であり、溶銑中で分解して反応域の温度を低
下させるので、脱燐に対して非常に有利な物質である。
また、上記物質は、溶銑中に粉の状態で吹き込まれるた
め、反応界面積が大きく、これも脱燐にとって好まし
い。これに対して、前記した転炉型の脱燐処理では、メ
インの酸素源は、溶銑に上吹きする酸素ガスである。溶
銑に対して多量に吹き付けられた酸素は、反応域で脱炭
反応も起こし、溶銑の温度を高め、脱燐反応に不利であ
る。また、転炉の炉上から塊状のＣａＯを添加するの
で，反応界面積は小さく、トピード型脱燐処理に比べて
不利である。In the topido type dephosphorization treatment, a dedicated lance is immersed in hot metal, and iron oxide and C
aO, CaF 2 etc. are blown. As carrier gas,
N 2 and O 2 are used. The main oxygen source that oxidizes phosphorus is iron oxide, which is a very advantageous substance for dephosphorization because it decomposes in hot metal and lowers the temperature of the reaction zone.
Further, since the above-mentioned substance is blown into the molten iron in a powder state, a reaction interface area is large, which is also preferable for dephosphorization. On the other hand, in the converter type dephosphorization process described above, the main oxygen source is oxygen gas blown upward to the hot metal. A large amount of oxygen blown to the hot metal also causes a decarburization reaction in the reaction zone, increasing the temperature of the hot metal, and is disadvantageous for the dephosphorization reaction. Further, since massive CaO is added from above the converter, the reaction interface area is small, which is disadvantageous as compared with the topped dephosphorization treatment.
【００２０】そこで、発明者は、このような脱燐反応へ
及ぼすプロセスの影響を配慮し、トピード転脱燐処理を
採用することにした。そして、本発明において重要なこ
とは、従来の精錬剤から蛍石を完全に除き、Ａｌ2Ｏ3を
使用するようにしたことである。これによって、スラグ
中に弗素がまったく存在しないようになる。この場合、
プリメルトされた焼結鉱を酸化鉄源に用いても良い。ま
た、蛍石の代替としてＡｌ2Ｏ3を使用するに当たって
は、耐火物の損耗を考慮する必要がある。つまり、トピ
ードのようにＡｌ2Ｏ3−ＳｉＣ−ＣといったＡｌ2Ｏ3系
耐火物の場合は、精錬剤にＡｌ2Ｏ3が混入しても問題な
い。しかし、転炉型脱燐の場合、同一転炉で溶銑脱燐、
脱炭を行なうことがある。その場合、耐火物保護を目的
とした石灰、ＭｇＯ源のスラグコーテイング層がＡｌ2
Ｏ3と低融点液相を形成し、耐火物損耗が増大するとい
った問題が生じる。Therefore, the inventor of the present invention has considered the effect of the process on such a dephosphorization reaction, and has decided to adopt a topido-dephosphorization treatment. What is important in the present invention is that fluorite is completely removed from the conventional refining agent, and Al 2 O 3 is used. This ensures that no fluorine is present in the slag. in this case,
Premelted sintered ore may be used as the iron oxide source. In using Al 2 O 3 as a substitute for fluorite, it is necessary to consider wear of refractories. In other words, in the case of an Al 2 O 3 refractory such as Al 2 O 3 —SiC—C, such as torpedo, there is no problem even if Al 2 O 3 is mixed in the refining agent. However, in the case of converter type dephosphorization, hot metal dephosphorization,
Decarburization may be performed. In that case, the slag coating layer of lime and MgO source for the purpose of refractory protection is made of Al 2
A problem arises in that a low melting point liquid phase is formed with O 3, and refractory wear is increased.
【００２１】以上述べた本発明に係る溶銑脱燐の実現性
を確認するため、図１に示すような３５０トン規模のト
ピードカー６を用い、通常通りのランス４を介した脱燐
剤２の吹き込み法で溶銑５の脱燐実験を行った。この脱
燐実験の条件は表１に示す通りである。脱燐剤２は、焼
結鉱及びＣａＯの混合物に従来と同等量の蛍石を添加し
たもの（水準１）と、蛍石の代替にＡｌ2Ｏ3を添加した
もの（水準２）の２種類とした。In order to confirm the feasibility of the hot metal dephosphorization according to the present invention as described above, the dephosphorizing agent 2 was blown through the lance 4 as usual using a 350 ton scale topped car 6 as shown in FIG. The dephosphorization experiment of the hot metal 5 was performed by the method. The conditions for this dephosphorization experiment are as shown in Table 1. The dephosphorizing agent 2 was composed of a mixture of sinter and CaO to which the same amount of fluorite was added as in the past (Level 1) and a mixture of fluorite and Al 2 O 3 instead of fluorite (Level 2). Type.
【００２２】脱燐結果を、酸素原単位と脱燐量（脱燐処
理前溶銑中燐濃度−脱燐処理後溶銑中燐濃度）との関係
で整理し、図２に示す。図２より、蛍石無しにしても、
代替としてＡｌ2Ｏ3を用いることにより、従来と同等の
脱燐が可能であることが明らかである。The results of the dephosphorization are shown in FIG. 2 in terms of the relationship between the specific oxygen content and the amount of dephosphorization (phosphorus concentration in hot metal before dephosphorization-phosphorus concentration in hot metal after dephosphorization). From Fig. 2, even without fluorite,
It is clear that the use of Al 2 O 3 as an alternative enables dephosphorization equivalent to the conventional one.
【００２３】[0023]
【表１】 [Table 1]
【００２４】一方、脱硫反応は（２）式で起きる。On the other hand, the desulfurization reaction takes place according to equation (2).
【００２５】 ［Ｓ］＋ＣａＯ→（ＣａＳ）＋［Ｏ］ （２） 脱硫剤としては、従来よりＣａＯ系、ソーダ灰系、Ｍｇ
系等がある。コスト面から、現在は、ＣａＯ系の脱硫剤
が主流となっている。この脱硫剤には蛍石が添加される
が、その蛍石は、スラグもしくはＣａＯ系脱硫剤の組織
（ネットワーク）を破断し、溶融を促進すると言われて
いる。発明者は、この蛍石に代えて、脱燐の場合と同様
にＡｌ2Ｏ3の使用を考えた。しかしながら、Ａｌ2Ｏ
3は、蛍石と同様にＣａＯ系脱硫剤の融点を低下させる
が、生成した液相の粘性が高くなり、脱硫剤を凝集させ
て反応界面積の低下を招く。従って、反応界面積増加の
ため、蛍石に代えてＡｌ2Ｏ3を用いるのは、脱硫処理で
は好ましくない。そこで、発明者は、脱硫剤への蛍石は
添加を従来通り行なうが、その使用量をできるだけ減ら
すことにした。また、脱硫プロセスとしては種々の方式
があるが、本発明では、機械攪拌方式を採用することに
した。この方式では、添加したＣａＯ系脱硫剤が、溶銑
中に巻き込まれて脱硫反応界面積が大きくなるため、精
錬剤の利用効率が高い利点があり、少ない精錬剤量でし
かも該精錬剤の溶融を促進する蛍石のような滓化促進剤
を低減しても、数ｐｐｍオーダの所謂「低硫黄域」濃度
までの脱硫処理が可能だからである。一方、トピードも
しくは取鍋（溶銑鍋ともいう）に溶銑を保持し、ＣａＯ
系脱硫剤をキャリアガスで吹き込むプロセス（所謂イン
ジェクション法）もある。このプロセスでは、粉状の脱
硫剤を吹き込むので、脱硫剤が溶銑中に滞留している間
は大きな反応界面積を有する。ところが、かかる脱硫剤
は、溶銑に対して比重が小さいので、大流量のキャリア
ガスに伴われ、数秒で溶銑の表面に浮上してしまい、固
体の割合が多いトップスラグを形成し、反応効率を低下
する。つまり、溶銑内での滞留時間が短く、機械攪拌方
式に比べて反応効率が低いので、本発明では、この方式
を採用しないことにしたのである。[S] + CaO → (CaS) + [O] (2) As the desulfurizing agent, CaO-based, soda-ash-based, Mg
System. At present, CaO-based desulfurizing agents are mainly used in terms of cost. Fluorite is added to the desulfurizing agent, and it is said that the fluorite breaks the structure (network) of the slag or CaO-based desulfurizing agent and promotes melting. The inventor has considered using Al 2 O 3 instead of the fluorite as in the case of dephosphorization. However, Al 2 O
No. 3 lowers the melting point of the CaO-based desulfurizing agent as in the case of fluorite, but increases the viscosity of the generated liquid phase and causes the desulfurizing agent to agglomerate, resulting in a decrease in the reaction interface area. Therefore, it is not preferable to use Al 2 O 3 instead of fluorite in the desulfurization treatment to increase the reaction interface area. Therefore, the inventor has made the addition of fluorite to the desulfurizing agent in the conventional manner, but has decided to reduce the amount of use as much as possible. In addition, there are various methods for the desulfurization process, but in the present invention, a mechanical stirring method is adopted. In this method, the added CaO-based desulfurizing agent is entrained in the hot metal and the area of the desulfurization reaction interface becomes large, so that there is an advantage in that the use efficiency of the refining agent is high. This is because desulfurization treatment to a so-called "low sulfur region" concentration of the order of several ppm is possible even if the slag formation accelerator such as fluorite is reduced. On the other hand, hot metal is held in a topied or ladle (also called hot metal ladle)
There is also a process of blowing a system desulfurizing agent with a carrier gas (a so-called injection method). In this process, since a powdery desulfurizing agent is blown, the desulfurizing agent has a large reaction interface area while staying in the hot metal. However, such a desulfurizing agent has a low specific gravity with respect to the hot metal, so that it is accompanied by a large flow rate of the carrier gas and floats on the surface of the hot metal in a few seconds, forming a top slag having a large percentage of solids, thereby reducing the reaction efficiency. descend. That is, since the residence time in the hot metal is short and the reaction efficiency is low as compared with the mechanical stirring method, this method is not adopted in the present invention.
【００２６】さらに、本発明では、上述した機械撹拌方
式を採用することにより、インジェクション法よりも精
錬剤や蛍石の使用量を従来より低減することができる
が、これをさらに低減させようとすると、脱硫反応効率
を別の手段で高める必要がある。そこで、発明者は、炭
化水素系ガスを利用することにした。そのガスは、３０
０℃程度で完全に分解（（３）式）して水素ガスを発生
し、該水素ガスが雰囲気の酸素ガス、溶銑中の［Ｏ］と
反応し（（４）、（５）式）て脱硫反応界面を還元雰囲
気にして、脱硫反応の促進に有利だからである。 ＣｎＨｍ→ｎＣ＋ｍ／２Ｈ2 （３） １／２Ｏ2＋Ｈ2→Ｈ2Ｏ （４） ［Ｏ］＋Ｈ2→Ｈ2Ｏ （５） しかも、ＣａＯによる溶銑の脱硫反応は、一般に（６）
式のように示されるが、（７）式のように、直接炭化水
素を反応に寄与させると、Ｃ−Ｈの共有結合に起因する
化学ポテンシャルにより、自由エネルギーが低下し、Ｈ
2に比べて脱硫に有利になると考えられる。Further, in the present invention, by employing the above-described mechanical stirring method, the amount of the refining agent or fluorite used can be reduced as compared with the conventional injection method, but it is desired to further reduce this. It is necessary to increase the desulfurization reaction efficiency by another means. Therefore, the inventor has decided to use a hydrocarbon-based gas. The gas is 30
It is completely decomposed at about 0 ° C. (formula (3)) to generate hydrogen gas, and the hydrogen gas reacts with oxygen gas in the atmosphere and [O] in the hot metal (formulas (4) and (5)). This is because the desulfurization reaction interface is set to a reducing atmosphere, which is advantageous for promoting the desulfurization reaction. CnHm → nC + m / 2H 2 (3) 1 / 2O 2 + H 2 → H 2 O (4) [O] + H 2 → H 2 O (5) In addition, desulfurization of hot metal by CaO generally involves (6)
When the hydrocarbon directly contributes to the reaction as in the equation (7), the free energy decreases due to the chemical potential caused by the covalent bond of C—H, and H
It is thought to be more advantageous for desulfurization than 2 .
【００２７】 ＣａＯ＋［Ｓ］＋［Ｃ］→ＣａＳ＋ＣＯ （６） ７ＣａＯ＋Ｃ3Ｈ8＋７［Ｓ］→７ＣａＳ＋３ＣＯ＋４Ｈ2Ｏ （７） 具体的な炭化水素ガスとしては、溶鋼へ吹込みの実績が
ある上記プロパンガスが好ましいが、コークス炉ガスも
使用できる。加えて、炭化水素としては、ガスにこだわ
る必要がなく、高温雰囲気下で炭化水素を発生するもの
であればいかなるものでも良いので、重油のような液
体、石炭、廃プラスティックのような固体、つまり炭化
水素を含む有機物質を脱硫剤に添加することも本発明に
加えることにした。CaO + [S] + [C] → CaS + CO (6) 7CaO + C 3 H 8 +7 [S] → 7CaS + 3CO + 4H 2 O (7) As a specific hydrocarbon gas, the above-mentioned propane which has a record of blowing into molten steel Gas is preferred, but coke oven gas can also be used. In addition, as the hydrocarbon, it is not necessary to stick to gas, and any substance that generates hydrocarbon under a high temperature atmosphere may be used.So, liquid such as heavy oil, coal, solid such as waste plastic, that is, The addition of organic substances containing hydrocarbons to the desulfurizing agent has also been added to the invention.
【００２８】以上述べた本発明に係る溶銑脱硫の実現性
を確認するため、発明者は、溶銑量５トン規模の機械攪
拌式溶銑脱硫実験を行なった。予め使用する炭化水素含
有物質からの炭化水素の発生量を調査するため、種々の
物質を用いてＮ2雰囲気中、１０００℃で乾留実験を行
った。得られた単位質量当たりの炭化水素ガスの発生量
を表２に示す。また、使用した機械攪拌式脱硫実験装置
を図３に、その実験条件を表３に、該実験で使用した炭
化水素の流量と見かけの脱硫効率との関係を図４に示
す。なお、図４の脱硫効率は、（８）式で定義したもの
である。 脱硫率（％）＝（△［Ｓ］／［Ｓ］ｉ）×１００＝[（［Ｓ］ｉ−［Ｓ］ｆ）／ ［Ｓ］ｉ]×１００ （８） ここで、Ｓｉ：処理前溶銑中Ｓ濃度、Ｓｆ：処理後溶銑
中Ｓ濃度 図４より、溶銑の脱硫効率が添加した炭化水素含有物質
の種類によらず、炭化水素の発生量（標準状態における
ガス量換算）で整理できることが明らかである。ここ
で、各物質からの炭化水素発生量は、表２から算出し
た。また、同実験において、炭化水素により蛍石をどの
程度低減できるかを確認するため、炭化水素の使用時に
おける蛍石原単位と脱硫効率との関係を求めた。その結
果を図５に示す。図５より、少量の蛍石でも、通常の蛍
石使用量（原単位で０．８ｋｇ／ｔ）並みの脱硫効率を
達成できることが明らかである。つまり、蛍石使用量を
従来より少なくしても、炭化水素を利用すれば、蛍石量
の低減による脱硫効率の低下を補充できることが確認で
きた。なお、この実験では、蛍石の代替としてＡｌ2Ｏ3
源または（Ａｌ＋Ａｌ2Ｏ3）で表すＡｌ灰のようなもの
を添加していないが、それらをＣａＯ系脱硫剤に混合し
てもかまわない。しかし、脱硫スラグを焼結工場へリサ
イクルする場合、焼結原料中のＡｌ2Ｏ3は、流動性を悪
化させるため、Ａｌ2Ｏ3源は少ない方が好ましい。In order to confirm the feasibility of the hot metal desulfurization according to the present invention as described above, the inventor conducted a mechanical stirring type hot metal desulfurization experiment on a scale of 5 tons of hot metal. In order to investigate the amount of hydrocarbons generated from the hydrocarbon-containing substances used in advance, dry distillation experiments were performed at 1000 ° C. in an N 2 atmosphere using various substances. Table 2 shows the amount of hydrocarbon gas generated per unit mass obtained. Further, FIG. 3 shows the mechanical stirring type desulfurization experiment apparatus used, Table 3 shows the experimental conditions, and FIG. 4 shows the relationship between the flow rate of the hydrocarbon used in the experiment and the apparent desulfurization efficiency. The desulfurization efficiency in FIG. 4 is defined by the equation (8). Desulfurization rate (%) = (△ [S] / [S] i) × 100 = [([S] i− [S] f) / [S] i] × 100 (8) where Si: before treatment S concentration in hot metal, Sf: S concentration in hot metal after treatment From FIG. 4, it can be seen that the desulfurization efficiency of hot metal can be summarized by the amount of generated hydrocarbons (converted to gas amount under standard conditions) regardless of the type of hydrocarbon-containing substance added. Is evident. Here, the amount of hydrocarbon generated from each substance was calculated from Table 2. In addition, in the same experiment, in order to confirm how much fluorite can be reduced by the hydrocarbon, the relationship between the fluorite intensity and the desulfurization efficiency when using the hydrocarbon was obtained. The result is shown in FIG. It is clear from FIG. 5 that even a small amount of fluorite can achieve a desulfurization efficiency comparable to the normal fluorite consumption (0.8 kg / t in basic unit). In other words, it was confirmed that even if the amount of fluorite used was smaller than before, the use of hydrocarbons could compensate for the decrease in desulfurization efficiency due to the reduction in the amount of fluorite. In this experiment, Al 2 O 3 was used as a substitute for fluorite.
No source or Al ash represented by (Al + Al 2 O 3 ) is added, but they may be mixed with a CaO-based desulfurizing agent. However, when the desulfurized slag is recycled to the sintering plant, Al 2 O 3 in the sintering raw material deteriorates the fluidity, so that it is preferable that the Al 2 O 3 source is small.
【００２９】[0029]
【表２】 [Table 2]
【００３０】[0030]
【表３】 [Table 3]
【００３１】次に、本発明では、製鉄所外へ排出するス
ラグからの弗素の溶出防止を最終目的としている。前記
したトピード型処理は、高炉からの溶銑搬送容器をその
まま流用でき、温度降下も少ない点で有利である。しか
し、その形状に起因してスラグの排出性が悪いという欠
点があり、蛍石を使用する脱硫処理をトピードカーで行
うと、弗素を含有するスラグが残留し、別途行なう脱燐
処理で排出するスラグに混入する恐れがある。脱燐処理
で排出するスラグは、ＳｉＯ2やP2Ｏ5含有量が高いの
で、スラグの滓化が進んでおり、水和膨脹が少ないた
め、路盤材等の用途に使用されることが多い。従って、
このような脱燐処理後のスラグに弗素が混入すると、環
境への弗素の溶出の恐れがあり、好ましくない。本発明
で、脱燐処理のみをトピードで行い、蛍石を使用する脱
硫処理をスラグの排出性の高い取鍋（溶銑装入鍋）で行
う理由は、このことを避けるためでもある。Next, in the present invention, the final object is to prevent the elution of fluorine from the slag discharged outside the steel works. The above-described torpedo type treatment is advantageous in that the hot metal transfer container from the blast furnace can be used as it is and the temperature drop is small. However, there is a drawback that the slag is poorly discharged due to its shape.If desulfurization treatment using fluorite is performed with a topped car, slag containing fluorine remains, and slag discharged in a separate dephosphorization treatment is used. May be mixed in. The slag discharged in the dephosphorization treatment has a high content of SiO 2 and P 2 O 5, so slag slag is advanced, and swelling due to hydration is small, so it is often used for applications such as roadbed materials. . Therefore,
If fluorine is mixed into the slag after the dephosphorization treatment, there is a possibility that fluorine may be eluted into the environment, which is not preferable. In the present invention, the reason why only the dephosphorization treatment is performed by the topido and the desulfurization treatment using the fluorite is performed by the ladle (hot metal charging ladle) having a high slag discharge property is also to avoid this.
【００３２】発明者は、この使用容器の問題を確認する
ため、残留スラグが付着していないトピードカー６、溶
銑装入鍋１１にスラグを装入し、それら容器１１からの
スラグ排出実験を行なった。両者での実施結果を比較し
て図６に示す。図６より、溶銑装入鍋１１からは、ほぼ
完全にスラグが除去されるのに対して、トピードカー６
からは装入した量の約２０％のスラグが排出困難である
ことが明らかである。In order to confirm the problem of the used container, the inventor charged slag into the torpedo car 6 and the hot metal charging pot 11 to which no residual slag was attached, and conducted a slag discharge experiment from the container 11. . FIG. 6 shows a comparison between the results of the two operations. 6, the slag is almost completely removed from the hot metal charging pan 11, whereas the topped car 6
It is clear from this that about 20% of the slag charged is difficult to discharge.
【００３３】本発明では、脱硫処理後のスラグは、弗素
含有量が従来よりはるかに低減しているが、それでもな
お、そのままでは環境への溶出基準を満足するまでに至
っていない。そこで、本発明では、この脱硫処理後のス
ラグを製銑工程にリサイクルし、最終的に高炉内で生成
するスラグでその弗素含有量を希釈させる。製銑工程へ
のリサイクル方法としては、脱硫処理後の形態のまま高
炉へ直接装入しても良い。しかし、焼結鉱の製造工程に
おいて鉄鉱石、コークス、石灰等の焼結原料に配合して
焼結鉱とするのが好ましい。脱硫スラグが、これら物質
の媒溶剤として作用し、焼結鉱の製造に役立つからであ
る。In the present invention, the slag after the desulfurization treatment has a much lower fluorine content than before, but still does not satisfy the standard for elution into the environment as it is. Therefore, in the present invention, the slag after the desulfurization treatment is recycled to the iron making process, and the fluorine content is finally diluted by the slag generated in the blast furnace. As a method for recycling to the iron making process, the iron may be directly charged into the blast furnace as it is after the desulfurization treatment. However, it is preferable to mix it with a sintering raw material such as iron ore, coke, lime or the like in the sinter production process to obtain sinter. This is because the desulfurized slag acts as a solvent for these substances and is useful for the production of sinter.
【００３４】次に、高炉スラグ中の弗素含有量と弗素溶
出量との関係を調査した。まず、弗素を含有しない高炉
スラグと蛍石を混合し、高周波溶解炉で１５００℃、２
時間処理し、水冷、空冷等の条件を変えて試料を作製し
た。そして、このようにして作製した試料の弗素溶出量
の定量を、以下の工程によって行なった。 （１）スラグの粉砕、（２）篩い分け；粒度０．５〜２
ｍｍのものを試料とする、（３）試料量；水１リットル
当たり１００ｇ、（４）振とう機による２００回／分×
６時間の振とう、（５）０．４５μｍ目のフィルタによ
る濾過、（６）残渣蒸留後のＩＣＰ分析 なお、スラグからの弗素溶出量については、０．０５ｍ
ｇ／リットルを検出限界として、限界以上と以下で結果
を整理した。その結果、高炉スラグ中の弗素含有量を１
０００ｐｐｍ以下にすれば、ばらつきを含めても、確実
に弗素溶出量が検出限界以下になることを見出した。Next, the relationship between the fluorine content in the blast furnace slag and the fluorine elution amount was investigated. First, a blast furnace slag containing no fluorine and fluorite are mixed, and the mixture is heated at 1500 ° C. in a high-frequency melting furnace.
The samples were processed for a time, and the conditions such as water cooling and air cooling were changed. Then, the amount of fluorine eluted from the sample thus prepared was quantified by the following steps. (1) slag crushing, (2) sieving; particle size 0.5-2
(3) Sample amount; 100 g per liter of water, (4) 200 times / min by a shaker ×
(5) Filtration with a 0.45 μm filter, (6) ICP analysis after residue distillation. The amount of fluorine eluted from the slag was 0.05 m.
The results were arranged above and below the limit with g / liter as the detection limit. As a result, the fluorine content in the blast furnace slag was reduced to 1
It has been found that when the concentration is set to 000 ppm or less, the fluorine elution amount surely falls below the detection limit, even if the dispersion is included.
【００３５】[0035]
【実施例】前記した本発明に係る溶銑の予備処理方法及
びそれと一部条件の異なる方法（比較例）とで溶銑の予
備処理を行なった。そして、得られたスラグからの弗素
溶出量を調査した。その際の脱燐処理、脱硫処理及び高
炉へのリサイクル内容を、一括して表４に示す。なお、
脱燐及び脱硫後には、全量のスラグを容器から排出して
いる。また、弗素溶出量の定量は、上述したものと同様
の工程順で行なった。EXAMPLE The hot metal pretreatment was carried out by the above-described method for pretreatment of hot metal according to the present invention and a method (comparative example) partially different from the method. Then, the amount of fluorine eluted from the obtained slag was investigated. Table 4 shows the contents of the dephosphorization treatment, desulfurization treatment and recycling to the blast furnace at that time. In addition,
After dephosphorization and desulfurization, the entire amount of slag is discharged from the container. Quantification of the fluorine elution amount was performed in the same process order as described above.
【００３６】弗素溶出量の調査結果を表５に示す。本発
明例１及び２では、トピードでの脱燐で蛍石を使用しな
いので、トピードからの排出スラグからの弗素の溶出は
なく、一方、機械攪拌脱硫において蛍石を使用するの
で、取鍋から排出されたスラグには、検出限界以上の弗
素が認められた。ただし、このスラグを、バランス上、
高炉スラグ中の弗素が１０００ｐｐｍ以下となるように
焼結原料の配合を決め、焼結工場にリサイクルした結
果、高炉内で希釈された高炉スラグは、検出限界以下と
なっている。このことより、トピードでの蛍石レスによ
る脱燐処理、取鍋での炭化水素吹込み、蛍石ミニマム添
加を伴う機械撹拌による脱硫処理、及び脱硫スラグの高
炉リサイクルによる弗素希釈により、高炉スラグ中弗素
は１０００ｐｐｍ以下となり、脱燐や脱硫の反応効率を
従来レベルから低下させることなく、製鉄所から排出す
るスラグ中に含まれる弗素の溶出を防止できることが明
らかである。Table 5 shows the results of the investigation on the fluorine elution amount. In Examples 1 and 2 of the present invention, no fluorite was used in dephosphorization with a tope, and no fluorine was eluted from the slag discharged from the tope. On the other hand, since fluorite was used in mechanical stirring desulfurization, a ladle was used. The discharged slag contained fluorine exceeding the detection limit. However, this slag, on balance,
The blending of the sintering raw materials was determined so that the fluorine in the blast furnace slag was 1000 ppm or less, and the blast furnace slag diluted in the blast furnace was below the detection limit as a result of recycling to a sintering plant. From this, the dephosphorization treatment without fluorite in the topido, the hydrocarbon injection in the ladle, the desulfurization treatment by mechanical stirring with the addition of fluorite minimum, and the fluorine dilution by recycling the desulfurization slag in the blast furnace slag, Fluorine is 1000 ppm or less, and it is clear that elution of fluorine contained in slag discharged from steel works can be prevented without reducing the reaction efficiency of phosphorus and desulfurization from the conventional level.
【００３７】[0037]
【表４】 [Table 4]
【００３８】[0038]
【表５】 [Table 5]
【００３９】[0039]
【発明の効果】以上説明したように、本発明により、反
応効率を落とすことなく溶銑の予備処理が可能となる。
また、製鉄所から排出する総てのスラグにおいて、弗素
の溶出が防止できるようになる。As described above, according to the present invention, pretreatment of hot metal can be performed without reducing reaction efficiency.
In addition, elution of fluorine can be prevented in all slag discharged from the steelworks.
【図１】本発明の実施に利用するトーピード型脱燐装置
を示す図である。FIG. 1 is a diagram showing a torpedo type dephosphorization apparatus used for carrying out the present invention.
【図２】溶銑に吹き込まれ、あるいは添加された酸素量
と脱燐効率との関係を示す図である。FIG. 2 is a diagram showing the relationship between the amount of oxygen blown or added to hot metal and the dephosphorization efficiency.
【図３】本発明の実施に利用する機械撹拌方式の脱硫装
置を示す図である。FIG. 3 is a view showing a mechanical stirring type desulfurization apparatus used for carrying out the present invention.
【図４】溶銑に吹き込まれ、あるいは添加された炭化水
素量と脱硫率との関係を示す図である。FIG. 4 is a graph showing the relationship between the amount of hydrocarbons blown or added to hot metal and the desulfurization rate.
【図５】溶銑に脱硫剤と共に添加された蛍石の原単位と
脱硫率との関係を示す図である。FIG. 5 is a diagram showing a relationship between a unit of fluorite added to hot metal together with a desulfurizing agent and a desulfurization rate.
【図６】トピードカーと溶銑装入鍋とからのスラグ排出
率の比較を示す図である。FIG. 6 is a diagram showing a comparison of slag discharge rates from a topped car and a hot metal charging pot.
１ 脱燐剤ホッパ ２ 脱燐剤 ３ ランス固定台車 ４ ランス ５ 溶銑 ６ トピードカー ７ 集塵フード ８ 撹拌子（インペラ） ９ ガス上吹きランス １０ 脱硫剤 １１ 取鍋（溶銑装入鍋） １２ キャリアガス DESCRIPTION OF SYMBOLS 1 Dephosphorizer hopper 2 Dephosphorizer 3 Lance fixed trolley 4 Lance 5 Hot metal 6 Tope car 7 Dust collecting hood 8 Stirrer (impeller) 9 Gas blowing lance 10 Desulfurizer 11 Ladle (hot metal charging pot) 12 Carrier gas
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ２１Ｃ 1/04 １０１ Ｃ２１Ｃ 1/04 １０１ 1/06 1/06 (72)発明者 小倉 滋 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 (72)発明者 竹内 秀次 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究所内 Ｆターム(参考） 4K014 AA01 AA02 AA03 AB02 AB03 AB04 AB16 AC03 AC08 AC14 AC16 AD01 AD23 AD27 AE01──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) C21C 1/04 101 C21C 1/04 101 1/06 1/06 (72) Inventor Shigeru Ogura Chiba, Chiba 1 Kawasaki-cho, Chuo-ku, Kawasaki Steel Engineering Co., Ltd. (72) Inventor Hideji Takeuchi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Pref. AB04 AB16 AC03 AC08 AC14 AC16 AD01 AD23 AD27 AE01
Claims (2)
含有する珪素、燐、硫黄を予め除去する溶銑予備処理に
おいて、 トピードカーに保持した前記溶銑に、蛍石を含まない精
錬剤をランスを介してキャリアガスで吹き込み脱珪及び
脱燐した後、その脱珪及び脱燐された溶銑を取鍋に移
し、蛍石を含む脱硫剤を添加して機械撹拌して脱硫する
と共に、該脱硫で生じた弗素含有スラグを高炉装入原料
の一部として使用し、該弗素含有スラグの弗素を希釈
し、弗素含有量１０００質量ｐｐｍ以下の高炉スラグと
して高炉から排出することを特徴とする溶銑の予備処理
方法。1. A hot metal pretreatment for removing silicon, phosphorus and sulfur contained in a hot metal before charging the hot metal into a steelmaking furnace, wherein the hot metal held in a torpedo car contains a fluorite-free refining agent. Is blown with a carrier gas through a lance to desiliconize and dephosphorize, transfer the hot metal desiliconized and dephosphorized to a ladle, add a desulfurizing agent containing fluorite and mechanically stir to desulfurize, The fluorine-containing slag generated by the desulfurization is used as a part of a blast furnace charge, the fluorine of the fluorine-containing slag is diluted, and the blast furnace slag having a fluorine content of 1000 mass ppm or less is discharged from the blast furnace. Hot metal pretreatment method.
スを吹込むあるいは炭化水素を含む有機物質を添加する
ことを特徴とする請求項１記載の溶銑の予備処理方法。2. The method for pretreatment of hot metal according to claim 1, wherein a hydrocarbon-based gas is blown into the hot metal during mechanical stirring or an organic substance containing hydrocarbon is added.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007031810A (en) * | 2005-07-29 | 2007-02-08 | Jfe Steel Kk | Desulfurizing treatment method for molten iron |
| KR100883820B1 (en) * | 2002-11-28 | 2009-02-16 | 주식회사 포스코 | A method for smelting dephosphorization in ladle while steel manufacture process |
| KR101038553B1 (en) | 2003-12-17 | 2011-06-02 | 주식회사 포스코 | Desilicifing method of hot metal with improved desilicifing rate |
| JP2012072473A (en) * | 2010-09-29 | 2012-04-12 | Jfe Steel Corp | Raw material for blast furnace, and method for manufacturing the same |
| JP2012092389A (en) * | 2010-10-27 | 2012-05-17 | Nippon Steel Corp | Recycling method of slug of torpedo car and pellet suited for blast furnace |
-
2000
- 2000-03-30 JP JP2000093564A patent/JP3797059B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100883820B1 (en) * | 2002-11-28 | 2009-02-16 | 주식회사 포스코 | A method for smelting dephosphorization in ladle while steel manufacture process |
| KR101038553B1 (en) | 2003-12-17 | 2011-06-02 | 주식회사 포스코 | Desilicifing method of hot metal with improved desilicifing rate |
| JP2007031810A (en) * | 2005-07-29 | 2007-02-08 | Jfe Steel Kk | Desulfurizing treatment method for molten iron |
| JP4715369B2 (en) * | 2005-07-29 | 2011-07-06 | Ｊｆｅスチール株式会社 | Hot metal desulfurization treatment method |
| JP2012072473A (en) * | 2010-09-29 | 2012-04-12 | Jfe Steel Corp | Raw material for blast furnace, and method for manufacturing the same |
| JP2012092389A (en) * | 2010-10-27 | 2012-05-17 | Nippon Steel Corp | Recycling method of slug of torpedo car and pellet suited for blast furnace |
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