JPH0826382B2 - Hot metal pretreatment method - Google Patents
Hot metal pretreatment methodInfo
- Publication number
- JPH0826382B2 JPH0826382B2 JP3301461A JP30146191A JPH0826382B2 JP H0826382 B2 JPH0826382 B2 JP H0826382B2 JP 3301461 A JP3301461 A JP 3301461A JP 30146191 A JP30146191 A JP 30146191A JP H0826382 B2 JPH0826382 B2 JP H0826382B2
- Authority
- JP
- Japan
- Prior art keywords
- hot metal
- desulfurization
- cao
- flux
- treatment
- 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.)
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- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は製鋼用溶銑の予備処理方
法に係り、特に脱珪（Si），脱燐（Ｐ）処理後の溶銑を
効率良く脱硫（Ｓ）することを目的とした溶銑の予備処
理方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment method for hot metal for steelmaking, and in particular, it aims at efficiently desulfurizing (S) the hot metal after desiliconization (Si) and dephosphorization (P). The present invention relates to the pretreatment method of.
【０００２】[0002]
【従来の技術】近年、高級鋼製造に対する要請が増大す
るにつれ、転炉精錬の前工程である溶銑の予備処理が重
要となり、特に極低Ｓ鋼や極低Ｐ鋼の転炉精錬に先立っ
て、脱Si後溶銑の脱Ｐ，脱Ｓ処理は必須の方法となって
いる。製鋼用溶銑の予備処理方法としては、 １）高炉の鋳床反応槽か傾注樋での脱珪剤（例えば酸化
鉄）のブラスティングあるいはインジェクションによる
脱Siとトピードカー若しくは溶銑鍋での脱Ｐ・脱Ｓ剤
（例えば、CaO,酸化鉄, 塩化カルシウム, 蛍石の混合
物）のインジェクションによる同時脱Ｐ，脱Ｓ、 ２）トピードカーでのインジェクションによる脱Siと引
き続いて溶銑鍋でインジェクションによる同時脱Ｐ・脱
Ｓ、 ３）高炉鋳床反応槽か傾注樋若しくはトピードカーでの
脱Siののち、転炉型の溶銑予備処理炉（多くの場合遊休
転炉の流用かそれの改造型）での脱Ｐ・脱Ｓ剤の上添加
と底吹ガス攪拌による脱Ｐ・脱Ｓ、のようなプロセスが
良く知られている。2. Description of the Related Art In recent years, as the demand for high-grade steel production has increased, pretreatment of molten pig iron, which is a pre-process of converter refining, has become important, especially prior to converter refining of ultra-low S steel and ultra-low P steel. , P removal and S treatment of hot metal after Si removal are essential methods. The pretreatment method for hot metal for steelmaking is as follows: 1) Desiliconization by blasting or injection of desiliconizing agent (for example, iron oxide) in a cast-bed reaction tank of a blast furnace or tilting gutter, and dephosphorization / dehydration by a tope car or a hot metal ladle. Simultaneous de-P and de-S by injection of S agent (for example, mixture of CaO, iron oxide, calcium chloride, and fluorspar), 2) De-Si by injection in a speeded car, and simultaneous de-P / de-injection by injection in a hot metal ladle. S, 3) De-Ping and de-oxidation in a converter-type hot metal pretreatment furnace (often used as an idle converter or its modification) after Si removal in a blast furnace casting bed reaction tank, tilted gutter or tope car Processes such as P addition and S removal by top addition of S agent and bottom blowing gas stirring are well known.
【０００３】これらのプロセスは、処理時間が比較的短
かくてもＰ≦ 0.020％の低Ｐ溶銑が得られ易いという長
所があるが、反面Ｓ＜ 0.005％、特にＳ≦ 0.003％の低
Ｓ溶銑を得るのが困難であるという欠点がある。これ
は、脱Ｐは酸化雰囲気で、脱Ｓは還元雰囲気でそれぞれ
良く進行するという相反する性質を同時に達成しようと
する矛盾に起因する。These processes have the advantage that a low P hot metal with P ≦ 0.020% can be easily obtained even if the processing time is relatively short, but on the other hand, a low S hot metal with S <0.005%, especially S ≦ 0.003% is obtained. Has the drawback that it is difficult to obtain. This is due to the contradiction of simultaneously attempting to achieve the contradictory properties that P is removed well in an oxidizing atmosphere and S is well removed in a reducing atmosphere.
【０００４】溶銑の予備処理方法に関する従来から良く
知られた上記の欠点を解決する方法として、例えば川崎
製鉄技報19(1987)４， 222〜 227には、溶銑の脱Ｐと脱
Ｓを分化し、脱Ｐ処理後に脱Ｓ処理を行う方法が提案さ
れている。この方法は脱硫剤としてソーダ灰を使用する
ことにより、フラックスコストの低減と極低Ｐ，Ｓ銑の
安定供給を可能とした。As a method for solving the above-mentioned drawbacks well known in the prior art regarding the hot metal pretreatment method, for example, in Kawasaki Steel Technical Report 19 (1987) 4, 222 to 227, de-P and de-S of hot metal are described. There is proposed a method of performing the deoxidizing treatment and the de-S treating treatment after the dephosphorizing treatment. By using soda ash as a desulfurizing agent, this method has made it possible to reduce the flux cost and to stably supply extremely low P and S pig iron.
【０００５】これは、脱硫剤として用いるソーダ灰が C
aO系に比べて溶銑中のＳとの親和力が高く、また比較的
低い溶銑温度でも優れた脱硫能を有するためである。反
面脱硫剤としてソーダ灰を用いると、予備処理スラグの
（Na2O) 濃度が高くなるためセメント原料や路盤材への
有効利用が出来なくなる。一方、金属Mgが優れた脱硫能
力を有することは古くから知られており、例えば、特開
昭 52-107218号公報や特開昭 52-115717号公報のように
金属Mg単独あるいは CaOやCaC2との混合物が溶銑脱硫剤
として用いられている。しかしながら、金属Mgは １）価格が高いため脱硫に要するコストが高くなる、 ２）沸点が低く蒸気圧が高いため高温ほど反応効率が低
くなる、 ３）脱Ｓ後に生成した MgSが次の（１）式の反応により
MgOとＳになり易いので処理後復硫が生じ易い、 MgS＋（Ｏ）＝MgO ＋Ｓ ・・・
（１） という欠点がある。This is because the soda ash used as a desulfurizing agent is C
This is because it has a higher affinity with S in the hot metal than the aO type and has an excellent desulfurization ability even at a relatively low hot metal temperature. On the other hand, when soda ash is used as the desulfurizing agent, the (Na 2 O) concentration of the pretreated slag becomes high, so that it cannot be effectively used as a cement raw material or a roadbed material. On the other hand, it has long been known that metal Mg has an excellent desulfurization ability, and for example, metal Mg alone or CaO or CaC 2 as in JP-A-52-107218 and JP-A-52-115717. Is used as a hot metal desulfurizing agent. However, metallic Mg is 1) expensive and therefore costly required for desulfurization. 2) Since boiling point is low and vapor pressure is high, the reaction efficiency becomes lower at higher temperature. 3) MgS produced after desulfurization has the following (1) ) By the reaction
MgS + (O) = MgO + S ...
There is a drawback of (1).
【０００６】そのため、その利用は高炉スラグが少量存
在するだけでかつ脱Si、脱Ｐ処理しない溶銑について目
標とする処理後Ｓ≧ 0.005％の脱硫処理用に限られてい
た。この場合にＳ＜ 0.005％の極低硫溶銑を得るにはCa
C2と金属Mg粉末の混合物から成る脱硫剤を多量に用いる
必要があり、CaC2を含むスラグを生成し、その処分に窮
することとなる。Therefore, the utilization thereof has been limited to desulfurization treatment with a target post-treatment S ≥ 0.005% for molten iron having only a small amount of blast furnace slag and not undergoing de-Si and de-P treatment. In this case, to obtain ultra-low sulfur hot metal with S <0.005%, Ca
It is necessary to use a large amount of desulfurizing agent composed of a mixture of C 2 and metallic Mg powder, and slag containing CaC 2 is produced, which makes it difficult to dispose of it.
【０００７】[0007]
【発明が解決しようとする課題】本発明は、脱硫剤とし
て金属Mgを含むフラックスを用いても前記従来の問題を
解決することができる溶銑の脱硫方法を提供することを
目的とするものである。SUMMARY OF THE INVENTION It is an object of the present invention to provide a hot metal desulfurization method capable of solving the above conventional problems even when a flux containing metal Mg is used as a desulfurizing agent. .
【０００８】[0008]
【課題を解決するための手段】前記目的を達成するため
の本発明は、脱Si, 脱Ｐ処理を行った溶銑について脱Ｓ
処理を行う溶銑の予備処理方法であって、脱Ｓ剤として
金属Mg粉末20〜95％と、 CaO若しくは CaOと CaCO3の混
合物５〜75％とを主成分とするフラックスを用い、該フ
ラックスによる脱Ｓ処理前のスラグ組成をCaO/SiO2 (重
量％比) ≧3.0、（Ｔ・Fe) ≦ 7.0％として、該フラッ
クスを搬送ガスとともに溶銑中にインジェクションする
か、若しくは上添加後あるいは上添加を行いつつ溶銑中
に気体吹込によるバブリング攪拌をして脱硫処理を行
い、溶銑のＳ含有量を0.005 ％以下とすることを特徴と
する溶銑の予備処理方法である。In order to achieve the above object, the present invention provides a method of removing S from the hot metal that has been subjected to the Si removal and P removal treatments.
A pretreatment method for hot metal to be treated, wherein a flux containing 20 to 95% of metallic Mg powder and 5 to 75% of CaO or a mixture of CaO and CaCO 3 as main components is used as a de-S agent. The flux is injected into hot metal together with carrier gas with CaO / SiO 2 (% by weight ratio) ≧ 3.0 and (T · Fe) ≦ 7.0% before de-S treatment, or after or over addition. The pretreatment method for hot metal is characterized in that the S content of the hot metal is 0.005% or less by performing a desulfurization treatment by bubbling stirring by blowing gas into the hot metal while performing the above.
【０００９】なお、前記の方法において、該フラックス
による脱Ｓ処理前の溶銑温度を1350℃以下とするのが好
ましい。In the above method, it is preferable that the hot metal temperature before the de-S treatment by the flux is 1350 ° C. or lower.
【００１０】[0010]
【作用】溶銑の脱Si, 脱Ｐ処理後に金属Mg粉末を含む脱
硫用フラックスを用いて脱Ｓ処理を行う場合に本発明に
よる著しい改善効果が得られる。すなわち脱Ｓ処理後に
脱Ｐ処理を行った場合に問題となっていた復Ｓや、同時
脱Ｐ・脱Ｓ処理で問題となっていた処理後のＳ≦ 0.005
％が得難いことや、溶銑温度低下が 100℃以上になるこ
とは本発明によりなくなり、Ｓ≦ 0.005％の溶銑が容易
に得られるようになる。さらにＳ≦0.003 ％の極低硫溶
銑も短時間処理で得られ、溶銑温度低下も30℃以下と小
さくなる。When the desulfurization treatment using the desulfurization flux containing the metal Mg powder after the hot metal desiliconization and dephosphorization treatment, the remarkable improvement effect of the present invention can be obtained. In other words, the recovery S that was a problem when the de-P process was performed after the de-S process, and the S ≤ 0.005 after the process that was a problem in the simultaneous de-P / S process.
%, The decrease in hot metal temperature to 100 ° C. or higher is eliminated by the present invention, and hot metal having S ≤ 0.005% can be easily obtained. Furthermore, extremely low sulfur hot metal with S ≤ 0.003% can be obtained in a short time, and the temperature drop of the hot metal is small at 30 ° C or less.
【００１１】このような成果は脱硫用フラックスを搬送
ガスとともに溶銑中にインジェクションする場合に最も
効果的に得られ、金属Mgの脱硫反応効率が高くなる。脱
硫用フラックスを上添加後あるいは上添加を行いつつ溶
銑中にＮ2 ガスを吹込んでバブリング攪拌をして脱硫処
理を行う場合でも比較的高い金属Mgの脱硫反応効率が得
られる。インジェクションする場合、インジェクション
速度は金属Mg粉末の吹込速度が小さい方が良く、0.05〜
0.40kgMg/min・t 、より望ましくは0.05〜 0.2kgMg/min
・ｔの範囲である。また、ランス深さを２ｍ以上とする
とさらに著しい改善効果が得られるため、ランス浸漬深
さがトピードカーに比べてより深くできる溶銑鍋がより
効果的である。Such results are most effectively obtained when the desulfurization flux is injected into the hot metal together with the carrier gas, and the desulfurization reaction efficiency of the metal Mg is increased. A relatively high desulfurization reaction efficiency of metal Mg can be obtained even when desulfurization treatment is performed by blowing N 2 gas into the hot metal and performing bubbling stirring after or while adding the desulfurization flux. When injecting, the injection speed is better when the injection speed of metal Mg powder is smaller, 0.05 ~
0.40kgMg / min ・ t, more preferably 0.05 to 0.2kgMg / min
・ It is a range of t. Further, when the lance depth is set to 2 m or more, a further remarkable improvement effect can be obtained. Therefore, a hot metal ladle capable of deepening the lance immersion depth is more effective than that of a toped car.
【００１２】また、金属Mgの粉末の粒径は小さすぎると
取扱いに注意を要するだけでなく、結果としてのMgの脱
硫反応効率が劣る。逆に粒径が大きすぎると吹込みの安
定性に欠けることおよび反応効率が低下する。Mgの粒径
は 100〜 400μが適当である。脱硫用フラックスとして
は、金属Mg粉末20〜95％、 CaO若しくは CaOと CaCO3の
混合物５〜75％を主成分とするものが有利に用いられ、
これらに10％以下のＣ粉および／または５％以下のAl粉
を含む脱硫用フラックスは金属Mgの脱硫反応効率を向上
させる効果が認められた。金属Mg粉末が20％未満の脱硫
フラックスでは脱硫処理に長時間を要する。金属Mg粉末
が95％を越えると価格も高く、取扱いに格別の注意を要
するだけで特に優れた効果が認められない。従って95％
以下で経済的に十分である。If the particle size of the powder of metallic Mg is too small, not only handling will be necessary, but the desulfurization efficiency of Mg will be poor as a result. On the other hand, if the particle size is too large, the blowing stability is insufficient and the reaction efficiency is reduced. A suitable Mg particle size is 100-400μ. As the desulfurization flux, those containing 20 to 95% of metallic Mg powder and 5 to 75% of CaO or a mixture of CaO and CaCO 3 as main components are advantageously used.
It was confirmed that the desulfurization flux containing 10% or less C powder and / or 5% or less Al powder improves the desulfurization reaction efficiency of metallic Mg. Desulfurization flux containing less than 20% of metal Mg powder requires a long time for desulfurization treatment. If the content of metal Mg powder exceeds 95%, the price is high, and special care is required in handling, and no particularly excellent effect is observed. Therefore 95%
The following is economically sufficient.
【００１３】脱硫用フラックスに CaO若しくは CaOと C
aCO3の混合物を５〜75％添加するのは先の（１）式の反
応により生じる復Ｓが生じるのを防ぐためである。すな
わち、より安定な CaSとしてスラグ中に吸収させると共
に、溶銑中に微細に均一分散した MgSを CaOのまわりに
付着させて浮上分離を促進させるためであり、５〜75％
の範囲が金属Mgの脱硫効果を発揮させるために適当であ
る。[0013] CaO or CaO and C as the flux for desulfurization
The reason why the aCO 3 mixture is added in an amount of 5 to 75% is to prevent S from being generated due to the reaction of the above formula (1). That is, the more stable CaS is absorbed in the slag, and the MgS finely and uniformly dispersed in the hot metal is deposited around CaO to promote floatation separation.
The range is suitable for exerting the desulfurization effect of metallic Mg.
【００１４】金属Mgの溶銑中への溶解量は、平衡論的に
は次の（２），（３）式で示される。 Mg(g) ＝Mg（％） ・・・
（２） log 〔％Mg〕＝7000／Ｔ−5.1 ＋ logＰMg ・・・
（３） したがって、溶銑温度が低いほど、またMg蒸気の分圧Ｐ
Mgが高いほど溶銑中にMgは溶解し易く、Mg蒸気として系
外に散逸する量が少ない。金属Mgを含む脱硫フラックス
による脱硫時の溶銑温度は1350℃以下が良く、1300℃以
下で行うとMgの脱硫反応効率がさらに向上する。The amount of metal Mg dissolved in the hot metal is shown by the following equations (2) and (3) in terms of equilibrium. Mg (g) = Mg (%) ・ ・ ・
(2) log [% Mg] = 7000 / T-5.1 + logP Mg ...
(3) Therefore, the lower the hot metal temperature, the more the Mg vapor partial pressure P
The higher the Mg , the more easily Mg dissolves in the hot metal, and the less the amount of Mg vapor dissipated out of the system. The hot metal temperature at the time of desulfurization with a desulfurization flux containing metallic Mg is preferably 1350 ° C or lower.
【００１５】また、脱硫用フラックスによる脱硫処理前
のスラグは適当な組成にする必要があり、残留する脱Ｐ
スラグは改質してCaO/SiO2（重量％）≧3.0, (Ｔ・Fe）
≦７％にするのが適当である。CaO/SiO2が 3.0未満であ
れば特にＳ＜ 0.005％で復Ｓが生じ易く、脱Ｓ処理後Ｓ
≦ 0.003％の極低Ｓ溶銑が得難くなる。スラグ中の（Ｔ
・Fe) が７％を越えると、スラグ中のFe酸化物の還元に
要するMg量が多大となり、Mgの脱硫反応効率が著しく低
下するばかりでなく脱Ｓ処理後に（１）式の反応により
復Ｓを生じる原因となる。Further, the slag before desulfurization treatment with the desulfurization flux must have an appropriate composition, and the residual dephosphorization
Slag is modified to CaO / SiO 2 (wt%) ≧ 3.0, (T ・ Fe)
It is suitable to be ≦ 7%. CaO / SiO 2 is likely to occur condensate S is in particular S <0.005% is less than 3.0, removal S processed S
It becomes difficult to obtain a very low S hot metal of ≤ 0.003%. (T in the slag
・ When Fe) exceeds 7%, the amount of Mg required for reduction of Fe oxide in the slag becomes large, and not only the desulfurization reaction efficiency of Mg remarkably decreases but also the recovery by the reaction of the formula (1) after the de-S treatment. It causes S.
【００１６】図１は本発明の実施に用いる溶銑予備処理
方法に係る手順を示している。すなわち、高炉９から出
銑されたその化学組成が大略Ｃ/4.5％, Si/0.3％, Mn/
0.2％, Ｐ/0.100％，Ｓ/0.03 ％である溶銑１は、鋳床
の反応槽２および／または傾注樋３でランス４を介して
ブラスティングされた脱Si剤によりSi＝0.05〜0.15％程
度に脱Siされ、トピードカー５に受銑する。FIG. 1 shows a procedure relating to the hot metal pretreatment method used for carrying out the present invention. That is, the chemical composition tapped from the blast furnace 9 is approximately C / 4.5%, Si / 0.3%, Mn /
0.2%, P / 0.100%, S / 0.03% of the hot metal 1 is Si = 0.05-0.15% due to the de-Si agent blasted through the lance 4 in the reaction chamber 2 and / or the down trough 3 of the casting bed. The silicon is removed to some extent and the pigeon car 5 receives it.
【００１７】脱Si後のスラグはトピードカー５からドラ
ッガー６を用いて除滓したのち、トピードカー５内に斜
めランス７を用いてインジェクションされた脱Ｐ剤によ
り、Ｐ＝ 0.010〜 0.050％程度に脱Ｐされる。脱Ｐ後の
スラグは改質されたのち、斜めランス７を用いて脱Ｓ剤
をインジェクションし所望のＳ、例えばＳ≦0.005 ％に
脱Ｓされる。予備処理後の溶銑は除滓ののち転炉８に製
鋼用溶銑として装入され、精錬される。After the Si removal, the slag is removed from the tope car 5 by using a dragger 6, and then P is removed to about P = 0.010 to 0.050% by a P removal agent injected using an oblique lance 7 in the tope car 5. To be done. After the P removal, the slag is modified, and then the S removal agent is injected using the oblique lance 7 to remove S to a desired S 2 , for example S 2 ≦ 0.005%. The hot metal after the pretreatment is removed from the slag and then charged into the converter 8 as hot metal for steelmaking and refined.
【００１８】本発明に基づく脱Ｓ処理は、脱Ｐ処理後ま
では図１に示した方法で行い、その後溶銑を溶銑鍋に移
し、溶銑鍋でインジェクション方式あるいは、上添加＋
ガス攪拌の方式により行ってもよい。以下、本発明の実
施例について説明する。The de-S treatment according to the present invention is carried out by the method shown in FIG. 1 until after the de-P treatment, and then the hot metal is transferred to a hot metal ladle, and the hot metal ladle is subjected to an injection method or top addition +
You may perform by the method of gas stirring. Examples of the present invention will be described below.
【００１９】〔実施例１〕 図１に示した溶銑予備処理方法に従って脱Si、脱Ｐ処理
を行ったのち、溶銑を溶銑鍋に移し、次のような条件下
で溶銑鍋内にて本発明に基づく脱Ｓ処理を行った。 ・溶銑量； 180〜 220ｔ ・脱Ｓ処理前の溶銑成分；Ｃ/4.1〜4.5 ％, Si/0.05 〜
0.15％, Mn/0.05〜0.15％，Ｐ/0.010〜0.040 ％, Ｓ/
0.020〜0.035 ％ ・脱硫用フラックスMg30〜CaO70 ％ ・インジェクション条件； 搬送ガス N2 ３〜６Nm3 /min 脱Ｓ用フラックスの吹込速度 0.03 〜0.50kgMg/min・
ｔ ランスの浸漬深さ 1.5〜2.6 ｍ 処理後のＳが 0.005％以下のものを選び、脱Ｓ処理前の
スラグ組成が（Ｔ・Fe) ≦５％の場合における復硫量
（転炉装入前−脱硫処理後）とスラグ組成CaO/SiO2との
関係を図２に示す。この図から明らかなように、スラグ
のCaO/SiO2≧ 3.0とすれば復硫量ΔＳを実質上問題のな
いレベルにすることができる。[Example 1] After desiliconization and deP treatment according to the hot metal pretreatment method shown in FIG. 1, the hot metal is transferred to a hot metal ladle, and the present invention is carried out in the hot metal ladle under the following conditions. S removal treatment based on・ Amount of hot metal; 180 to 220t ・ Hot metal component before de-S treatment; C / 4.1 to 4.5%, Si / 0.05 to
0.15%, Mn / 0.05 to 0.15%, P / 0.010 to 0.040%, S /
0.020 to 0.035% ・ Desulfurization flux Mg30 to CaO70% ・ Injection conditions; Carrier gas N 2 3 to 6 Nm 3 / min Desulfurization flux blowing rate 0.03 to 0.50 kgMg / min ・
t Lance immersion depth 1.5 to 2.6 m Select S with 0.005% or less after treatment, and if the slag composition before S treatment is (T · Fe) ≦ 5%, the amount of vulcanization (converter charging The relationship between (before-after desulfurization) and the slag composition CaO / SiO 2 is shown in FIG. As is clear from this figure, if CaO / SiO 2 ≧ 3.0 of the slag, the amount of re-sulfurization ΔS can be made to a level at which there is practically no problem.
【００２０】図３はスラグ中の（Ｔ・Fe) とMgの脱硫反
応への利用効率を調べたもので、スラグ中のCaO/SiO2≧
3.0のもののみを選びプロットした。この図から明らか
なように、Mgの反応効率はスラグ中の（Ｔ・Fe) が７％
を越えると著しく低下する。なお、Mgの脱硫反応効率は
下記式の通りである。FIG. 3 shows the utilization efficiency of (T · Fe) and Mg in the slag for the desulfurization reaction. CaO / SiO 2 ≧
Only 3.0 was selected and plotted. As is clear from this figure, the reaction efficiency of Mg is (T · Fe) 7% in the slag.
If it exceeds, it will decrease significantly. The Mg desulfurization reaction efficiency is as shown in the following formula.
【００２１】[0021]
【数１】 [Equation 1]
【００２２】図４は処理時の溶銑温度とMgの脱硫反応効
率の関係を示したもので、スラグ中のCaO/SiO2≧ 3,
（Ｔ・Fe) ≦５％，処理後Ｓ＜ 0.005％のもののみを選
んだ。溶銑温度が1350℃以下の方がMgの脱硫反応効率が
高い。 〔実施例２〕 脱Si、脱Ｐ処理を行った溶銑を実施例１と同様溶銑鍋に
移し、脱硫用フラックスの組成を変えてインジェクショ
ン脱硫を行った場合の脱硫成績を表１に示す。操業条件
は以下に示す。なお、溶銑量、脱Ｓ処理前の溶銑成分は
実施例１とほぼ同じであり、また、実施例１にしたがい
脱Ｓ処理前のスラグ組成は、（Ｔ・Fe)≦５％，CaO/SiO
2≧ 3.0に制御した。FIG. 4 shows the relationship between the hot metal temperature during the treatment and the desulfurization reaction efficiency of Mg. CaO / SiO 2 ≧ 3 in the slag.
Only (T · Fe) ≦ 5% and S <0.005% after treatment were selected. The desulfurization reaction efficiency of Mg is higher when the hot metal temperature is 1350 ° C or lower. [Example 2] Table 1 shows the desulfurization results in the case where the hot metal subjected to the Si removal and P removal treatment was transferred to the hot metal ladle as in Example 1, and the composition of the desulfurization flux was changed to perform the injection desulfurization. The operating conditions are shown below. The amount of hot metal and the hot metal component before de-S treatment were almost the same as in Example 1, and the slag composition before De-S treatment was (T · Fe) ≦ 5%, CaO / SiO 2 according to Example 1.
Controlled to 2 ≧ 3.0.
【００２３】 処理時の溶銑温度 1250〜1300℃ 脱硫用フラックスの吹込速度 0.03〜0.10kgMg/min・
ｔ 搬送ガス N2 ４〜５Nm3/min ランスの浸漬深さ 2.0 〜 2.4ｍHot metal temperature during treatment 1250 to 1300 ° C Desulfurization flux blowing rate 0.03 to 0.10 kgMg / min
t Carrier gas N 2 4 to 5 Nm 3 / min Lance immersion depth 2.0 to 2.4 m
【００２４】[0024]
【表１】 [Table 1]
【００２５】表１に示すように本発明例のフラックスに
よれば、金属Mgおよび CaOが本発明の範囲外の組成とな
っている比較例に較べてMgの脱硫効率が良く処理後の溶
銑Ｓを安定して 0.005％以下とすることができる。As shown in Table 1, according to the flux of the present invention, the desulfurization efficiency of Mg was better than that of the comparative example in which the compositions of metal Mg and CaO were out of the range of the present invention, and the hot metal S after treatment was treated. Can be stably maintained at 0.005% or less.
【００２６】[0026]
【発明の効果】本発明に基づく溶銑予備処理方法によれ
ば次のような効果が得られる。 １）金属Mgの脱硫効率が向上するため極低Ｐ，極低Ｓの
製鋼用溶銑が極めて経済的に安価に得られる。 ２）溶銑予備処理時の温度低下が小さいので、予備処理
時に気体酸素を用いた２次燃焼による温度補償の必要が
なく、したがって耐火物損傷が少ない。また、転炉装入
時の溶銑温度が高くなるので、鉄鉱石やMn鉱石の投入量
を多くすることが可能となり、したがってFe歩留の上
昇, FeMn合金添加量の低減などの効果がある。 ３）予備処理スラグのセメント、路盤材等への再利用が
図られ、産業廃棄物とする必要がなくなる。According to the hot metal pretreatment method of the present invention, the following effects can be obtained. 1) Since the desulfurization efficiency of metal Mg is improved, extremely low P and extremely low S hot metal for steelmaking can be obtained extremely economically at low cost. 2) Since the temperature drop during the hot metal pretreatment is small, there is no need for temperature compensation by secondary combustion using gaseous oxygen during the pretreatment, and therefore the refractory damage is small. In addition, since the hot metal temperature at the time of charging the converter becomes high, it is possible to increase the amount of iron ore or Mn ore input, and therefore, there are effects such as an increase in Fe yield and a decrease in the amount of FeMn alloy added. 3) The pre-treated slag can be reused for cement, roadbed material, etc., and it is no longer necessary to treat it as industrial waste.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の実施に用いる溶銑予備処理方法に係る
手順の説明図である。FIG. 1 is an explanatory diagram of a procedure related to a hot metal pretreatment method used for carrying out the present invention.
【図２】脱硫実験における復硫量（転炉装入前−脱硫処
理後）とスラグ組成との関係を示すグラフである。FIG. 2 is a graph showing the relationship between the amount of re-sulfurization (before charging the converter-after desulfurization) and the slag composition in a desulfurization experiment.
【図３】スラグ中の（Ｔ・Fe）とMgの脱硫反応効率との
関係を示すグラフである。FIG. 3 is a graph showing the relationship between (T · Fe) in slag and the desulfurization reaction efficiency of Mg.
【図４】処理時における溶銑温度とMgの脱硫反応効率と
の関係を示すグラフである。FIG. 4 is a graph showing the relationship between hot metal temperature and Mg desulfurization reaction efficiency during treatment.
【符号の説明】 １ 溶銑 ２ 反応槽 ３ 傾注樋 ４ ランス ５ トピードカー ６ ドラッガー ７ ランス ８ 転炉[Explanation of symbols] 1 Hot metal 2 Reaction tank 3 Inclined gutter 4 Lance 5 Topeed car 6 Dragger 7 Lance 8 Converter
───────────────────────────────────────────────────── フロントページの続き (72)発明者 数土 文夫 岡山県倉敷市水島川崎通１丁目（番地な し） 川崎製鉄株式会社 水島製鉄所内 (56)参考文献 特開 昭51−22614（ＪＰ，Ａ) 特開 昭52−115717（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumio Sato, Inventor 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (no address), Kawasaki Steel Co., Ltd., Mizushima Works (56) Reference JP-A-51-22614 A) JP-A-52-115717 (JP, A)
Claims (2)
硫処理を行う溶銑の予備処理方法であって、脱硫剤とし
て重量％で金属Mg粉末20〜95％と、 CaO若しくは CaOと
CaCO3の混合物５〜75％とを主成分とするフラックスを
用い、該フラックスによる脱硫処理前のスラグ組成をCa
O/SiO2（重量％比）≧3.0,（Ｔ・Fe)≦ 7.0重量％とし
て、該フラックスを搬送ガスとともに溶銑中にインジェ
クションするか、若しくは上添加後あるいは上添加を行
いつつ溶銑中に気体吹込によるバブリング撹拌をして脱
硫処理を行い、溶銑中のＳ含有量を0.005 重量％以下と
することを特徴とする溶銑の予備処理方法。1. A hot metal pretreatment method for desulfurization of hot metal that has been subjected to desiliconization and dephosphorization, comprising 20 to 95% by weight of metallic Mg powder as a desulfurizing agent, and CaO or CaO.
Using a flux whose main component is a mixture of CaCO 3 and 5 to 75%, the slag composition before desulfurization treatment with the flux is Ca
O / SiO 2 (wt% ratio) ≧ 3.0, (T · Fe) ≦ 7.0 wt%, the flux is injected into the hot metal together with the carrier gas, or gas is added to the hot metal after or during the above addition. A pretreatment method for hot metal, characterized in that the sulfur content in the hot metal is 0.005% by weight or less by performing desulfurization treatment by bubbling and stirring by blowing.
硫処理を行う溶銑の予備処理方法であって、脱硫剤とし
て重量％で金属Mg粉末20〜95％と、 CaO若しくは CaOと
CaCO3の混合物５〜75％とを主成分とするフラックスを
用い、該フラックスによる脱硫処理前の溶銑温度を1350
℃以下とし、さらにスラグ組成をCaO/SiO2（重量％比）
≧3.0,（Ｔ・Fe) ≦ 7.0重量％として、該フラックスを
搬送ガスとともに溶銑中にインジェクションするか、若
しくは上添加後あるいは上添加を行いつつ溶銑中に気体
吹込によるバブリング撹拌をして脱硫処理を行い、溶銑
中のＳ含有量を0.005 重量％以下とすることを特徴とす
る溶銑の予備処理方法。2. A method for pretreatment of hot metal for desulfurization of hot metal that has been subjected to desiliconization and dephosphorization, comprising 20 to 95% by weight of metal Mg powder as a desulfurizing agent, and CaO or CaO.
Using a flux whose main component is a mixture of CaCO 3 and 5 to 75%, the hot metal temperature before desulfurization treatment with the flux is 1350.
℃ or less, and the slag composition is CaO / SiO 2 (weight% ratio)
≧ 3.0, (T · Fe) ≦ 7.0 wt%, the flux is injected into hot metal together with carrier gas, or desulfurization is performed by bubbling stirring by gas injection into hot metal after or while top addition. And a S content in the hot metal of 0.005% by weight or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3301461A JPH0826382B2 (en) | 1991-11-18 | 1991-11-18 | Hot metal pretreatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3301461A JPH0826382B2 (en) | 1991-11-18 | 1991-11-18 | Hot metal pretreatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05140626A JPH05140626A (en) | 1993-06-08 |
| JPH0826382B2 true JPH0826382B2 (en) | 1996-03-13 |
Family
ID=17897178
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3301461A Expired - Fee Related JPH0826382B2 (en) | 1991-11-18 | 1991-11-18 | Hot metal pretreatment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0826382B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6024192B2 (en) * | 2012-05-15 | 2016-11-09 | Ｊｆｅスチール株式会社 | Method for preventing hot metal after desulphurization |
| JP6416634B2 (en) * | 2015-01-19 | 2018-10-31 | 株式会社神戸製鋼所 | Desiliconization and desulfurization methods in hot metal ladle |
| CN109112247A (en) * | 2018-10-23 | 2019-01-01 | 武汉钢铁有限公司 | Composite blowing iron melt desulfurizing agent and its sulfur removal technology |
| CN111206134A (en) * | 2020-02-24 | 2020-05-29 | 本钢板材股份有限公司 | Method for improving desulfurization effect by adding limestone in molten iron desulfurization by blowing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5122614A (en) * | 1974-08-21 | 1976-02-23 | Nippon Steel Corp | DATSURYUZAI |
| JPS52115717A (en) * | 1976-03-25 | 1977-09-28 | Sumitomo Metal Ind Ltd | Desulfurization of steel |
-
1991
- 1991-11-18 JP JP3301461A patent/JPH0826382B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05140626A (en) | 1993-06-08 |
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