JP2011137196A - Desiliconizing and dephosphorizing method for molten iron - Google Patents
Desiliconizing and dephosphorizing method for molten iron Download PDFInfo
- Publication number
- JP2011137196A JP2011137196A JP2009296860A JP2009296860A JP2011137196A JP 2011137196 A JP2011137196 A JP 2011137196A JP 2009296860 A JP2009296860 A JP 2009296860A JP 2009296860 A JP2009296860 A JP 2009296860A JP 2011137196 A JP2011137196 A JP 2011137196A
- Authority
- JP
- Japan
- Prior art keywords
- slag
- treatment
- hot metal
- furnace
- removal
- 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
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Description
本発明は、転炉型の溶銑の脱Ｓｉ脱Ｐ処理方法に関するものであり、特に脱Ｓｉ処理を行った後に中間排滓を行う溶銑の脱Ｓｉ脱Ｐ処理方法に関するものである。 The present invention relates to a converter type hot metal de-Si removal P treatment method, and more particularly to a hot metal de-Si removal P treatment method in which intermediate waste is performed after de-Si treatment.
転炉型の炉内で溶銑の脱Ｓｉ脱Ｐなどの溶銑予備処理を行うことは、特許文献１に示されるように従来から行われており、脱Ｓｉ脱Ｐ処理された溶銑はさらに転炉内で脱Ｃ処理されたうえ、鋳造工程に送られている。また特許文献１には、脱Ｓｉ処理と脱Ｐ処理との間で脱Ｓｉスラグをスラグパンに排出する中間排滓を行うことにより、脱Ｓｉ脱Ｐに要するＣａＯ源を節減できることも開示されている。 Performing hot metal preliminary treatment such as hot metal de-Si removal P in a converter type furnace has been conventionally performed as shown in Patent Document 1, and the hot metal subjected to de-Si de-P treatment is further converted into a converter. After being de-C treated, it is sent to the casting process. Further, Patent Document 1 discloses that the CaO source required for de-Si de-P can be reduced by performing intermediate waste for discharging de-Si slag to the slag pan between de-Si treatment and de-P treatment. .
この中間排滓は転炉型の精錬炉を傾動させ、溶銑の表層に浮上しているスラグのみを流出させることによって行われるが、中間排滓を円滑に行うためには、脱Ｓｉ処理工程において発生するスラグの流動性が十分に高いことが必要である。このためには脱Ｓｉ処理終了時のスラグのＣａＯ/ＳｉＯ２を０．３〜１．３の範囲に調整することが必要であると特許文献1に開示されている。例えば主に塊生石灰を用いてＣａＯ分の調整を行うと、塊生石灰はＣａＯ：９４％、その他：６％の組成を有し、その融点は２９２７℃であり溶解に長時間を要するため、従来は融点が１３５０℃である蛍石を併用し、１０分程度の短時間で中間排滓できる程度までスラグの流動性を高めていた。ところが、フッ素を含有する蛍石を使用した処理工程から発生したスラグを地中に埋設したり路盤材などとして使用したりすることは土壌規制に抵触することとなったため、現状では蛍石を使用することができなくなっており、脱Ｓｉ後に中間排滓を行う操業形態は実施困難である。 This intermediate waste is performed by tilting the converter-type smelting furnace and letting out only the slag floating on the surface layer of the hot metal, but in order to smoothly carry out the intermediate waste, in the de-Si treatment process It is necessary that the fluidity of the generated slag is sufficiently high. For this purpose, Patent Document 1 discloses that it is necessary to adjust the CaO / SiO2 of the slag at the end of the Si removal treatment to a range of 0.3 to 1.3. For example, when adjusting the CaO content mainly using bulk lime, the bulk lime has a composition of CaO: 94%, others: 6%, its melting point is 2927 ° C., and it takes a long time to dissolve. In combination with fluorite having a melting point of 1350 ° C., the fluidity of the slag was increased to such an extent that it could be eliminated in a short time of about 10 minutes. However, burying slag generated from the treatment process using fluorine-containing fluorite in the ground or using it as roadbed material has been in conflict with soil regulations, so fluorite is currently used. Therefore, it is difficult to carry out an operation mode in which intermediate evacuation is performed after Si removal.
また、蛍石を併用して１０分程度の短時間で脱Ｓｉを終了し中間排滓を行ったとしても、その間に溶銑中のＳｉ濃度が０．１％以下になるまで脱Ｓｉが進行していた。このように脱Ｓｉが進行すると続いて脱Ｃ反応が開始し、Ｃ＋（１/２）Ｏ２→ＣＯの反応によりＣＯが発生し、溶銑を激しく撹拌する。その結果、脱Ｓｉスラグ中に粒鉄が巻き込まれて外部に排出されることとなり、溶鋼歩留まりを悪化させていた。なお本明細書において％はすべて質量％を意味するものとする。 Moreover, even if the removal of Si is completed in a short time of about 10 minutes by using fluorite together and the intermediate waste is performed, the removal of Si proceeds during that time until the Si concentration in the molten iron becomes 0.1% or less. It was. Thus, when the Si removal progresses, the de-C reaction starts, and CO is generated by the reaction of C + (1/2) O 2 → CO, and the molten iron is vigorously stirred. As a result, granular iron is involved in the de-Si slag and discharged to the outside, which deteriorates the molten steel yield. In the present specification, “%” means “% by mass”.
また、脱Ｓｉ処理後にスラグをスラグパンに中間排滓するとき、スラグパン内で粒鉄とスラグがＣ＋ＦｅＯ→Ｆｅ＋ＣＯの反応を生じて突沸し、発生するＣＯガスによってスラグが流出するというトラブルが発生することがあった。このように、中間排滓によるＣａＯ源の節減を図ろうとすると、溶鋼歩留まりを悪化させたり、スラグパンからのスラグの流出が生じたりすることがあった。 Also, when the slag is discharged into the slag pan after the Si removal treatment, there is a problem that the granular iron and slag cause a reaction of C + FeO → Fe + CO in the slag pan and bump into the slag, and the slag flows out due to the generated CO gas. was there. Thus, when trying to save the CaO source by the intermediate waste, the molten steel yield may be deteriorated or the slag may flow out from the slag pan.
従って本発明の目的は上記した従来の問題点を解決し、蛍石を使用することなく中間排滓時のスラグの流動性を改善して溶鋼歩留まりの悪化やスラグの流出を防止するとともに、中間排滓によるＣａＯ源の削減を図ることができる溶銑の脱Ｓｉ脱Ｐ処理方法を提供することである。 Therefore, the object of the present invention is to solve the above-mentioned conventional problems, improve the fluidity of the slag at the time of intermediate discharge without using fluorite, prevent deterioration of the molten steel yield and slag outflow, It is an object of the present invention to provide a hot metal de-Si de-P treatment method capable of reducing the CaO source by waste.
上記の課題を解決するためになされた本発明は、転炉型の炉内で溶銑の脱Ｓｉ処理を行った後に中間排滓を行い、同一の炉内でさらに脱Ｐ処理を行う溶銑の脱Ｓｉ脱Ｐ処理方法において、この脱Ｐ処理より後工程において発生するスラグを脱Ｓｉ処理を行う炉内に投入し、スラグ塩基度（ＣａＯ／ＳｉＯ２）を０．５〜１．８の範囲に調整して脱Ｓｉ処理を行うことを特徴とするものである。なお、溶銑中のＳｉ濃度が０．２％以上の状態で中間排滓を行うことが好ましく、脱Ｐ処理より後工程において発生するスラグとして、脱Ｃ炉において発生する転炉スラグあるいは鋳造工程において発生する造塊スラグを用いることが好ましい。 The present invention, which has been made to solve the above-mentioned problems, is to remove hot metal in which an intermediate waste is performed after a hot metal de-Si treatment in a converter type furnace, and a further de-P treatment is performed in the same furnace. In the Si de-P treatment method, slag generated in the post-process after this de-P treatment is introduced into a furnace for de-Si treatment, and the slag basicity (CaO / SiO 2) is adjusted to a range of 0.5 to 1.8. Then, the Si removal process is performed. In addition, it is preferable to perform intermediate waste in a state where the Si concentration in the hot metal is 0.2% or more, and in the converter slag generated in the de-C furnace or the casting process as slag generated in the post-process after the de-P treatment. It is preferable to use the generated agglomerated slag.
本発明の溶銑の脱Ｓｉ脱Ｐ処理方法は、転炉型の炉内で溶銑の脱Ｓｉ処理を行った後に中間排滓を行うことにより、ＣａＯ源を節減できることは従来と同様であるが、従来とは異なり脱Ｐ処理よりも後工程において発生するスラグ、代表的には転炉スラグを脱Ｓｉ処理を行う炉内に投入することにより、スラグ塩基度（ＣａＯ／ＳｉＯ２）を０．５〜１．８の範囲に調整して脱Ｓｉ処理を行う。転炉スラグは融点が蛍石と同様に約１３５０℃であるから溶け易く、特にスラグ塩基度を０．５〜１．８の範囲に調整すると、１３００℃においてスラグの液相率が高く、流動性が高まるので中間排滓を円滑に行うことができる。このためＣａＯ源として塊生石灰のみ、もしくは蛍石を併用した場合よりも溶解時間を大幅に短縮でき、例えば５分程度で脱Ｓｉ処理を終了することができる。 The hot metal de-Si removal P treatment method of the present invention is similar to the conventional method that the CaO source can be saved by performing intermediate waste after performing de-Si treatment of hot metal in a converter type furnace, Unlike conventional methods, slag generated in a post-process rather than de-P treatment, typically, converter slag is introduced into a furnace that performs de-Si treatment, so that slag basicity (CaO / SiO2) is 0.5 to The Si removal treatment is performed within the range of 1.8. Converter slag has a melting point of about 1350 ° C. like fluorite, so it is easy to melt. Especially when the slag basicity is adjusted in the range of 0.5 to 1.8, the liquid phase rate of slag is high at 1300 ° C. Since the property is improved, the intermediate waste can be smoothly performed. For this reason, dissolution time can be significantly shortened compared with the case of using only lump lime or fluorite as a CaO source. For example, the de-Si treatment can be completed in about 5 minutes.
この段階では溶銑中のＳｉ濃度は０．２％以上のレベルにあり、未だ溶銑の脱Ｃ反応は生じない。従って従来のように脱Ｃ反応に伴って発生するガスによる溶銑の撹拌がなくなり、脱Ｓｉスラグ中に粒鉄が巻き込まれることもなくなるので、溶鋼歩留まりが向上する。また、脱Ｓｉ処理後にスラグをスラグパンに中間排滓するとき、スラグパン内で粒鉄とスラグが反応することもなくなり、発生するガスによるスラグの流出も防止することができる。従って本発明によれば、蛍石を使用することなく中間排滓によるＣａＯ源の節減を図ることができ、しかも溶鋼歩留まりを悪化させたり、スラグパンからのスラグの流出が生じたりすることをなくすることができる。 At this stage, the Si concentration in the hot metal is at a level of 0.2% or higher, and the hot metal de-C reaction does not occur yet. Therefore, the hot metal is not stirred by the gas generated with the de-C reaction as in the prior art, and the granular iron is not involved in the de-Si slag, so that the molten steel yield is improved. Further, when the slag is intermediately discharged into the slag pan after the Si removal treatment, the granular iron and the slag do not react in the slag pan, and the outflow of the slag by the generated gas can be prevented. Therefore, according to the present invention, it is possible to reduce the CaO source by intermediate waste without using fluorite, and to prevent the deterioration of molten steel yield and the outflow of slag from the slag pan. be able to.
以下に本発明の実施形態を示す。
図１は本発明の実施形態を示す説明図であり、高炉により製造された銑鉄は転炉型の炉（精錬炉）１に注入され、例えば上吹ランス２から高圧酸素を吹き込んで脱Ｓｉ処理を行う。この脱Ｓｉ処理において生ずるＳｉＯ２を捕捉させるため、本発明では脱Ｐ処理よりも後工程において発生するスラグを脱Ｓｉ処理工程に返送して使用する。脱Ｐ処理よりも後工程は一般的には転炉３における脱Ｃ工程及び鋳造工程であるから、脱Ｐ処理よりも後工程において発生するスラグとは、脱Ｃ工程から発生した転炉スラグまたは鋳造工程から発生した造塊スラグ（取鍋内に残留するスラグ）を意味する。
Embodiments of the present invention will be described below.
FIG. 1 is an explanatory view showing an embodiment of the present invention. Pig iron produced by a blast furnace is injected into a converter type furnace (smelting furnace) 1 and, for example, high pressure oxygen is blown from an upper blowing lance 2 to remove Si. I do. In order to capture the SiO 2 generated in the de-Si process, in the present invention, the slag generated in the post-process after the de-P process is returned to the de-Si process and used. Since the post-process is generally a de-C process and a casting process in the converter 3 than the de-P process, the slag generated in the post-process rather than the de-P process is the converter slag generated from the de-C process or It means ingot slag generated from the casting process (slag remaining in the ladle).
本発明ではこれらの転炉スラグや造塊スラグを炉１内に投入し、脱Ｓｉ処理終了時におけるスラグ塩基度（ＣａＯ／ＳｉＯ２）が０．５〜１．８の範囲となるように調整しながら、脱Ｓｉ処理を行う。図２はＳｉＯ２−ＣａＯ−ＦｅＯの３元図の１３００℃における等温断面図であり、グラフ中にＣａＯ／ＳｉＯ２が０．５の直線と、ＣａＯ／ＳｉＯ２が１．８の直線を示した。このグラフに示されるように、この範囲内においてはスラグは液相を形成し易く、優れた流動性を得ることができるが、塩基度がこの範囲を外れると融点が上昇する。グラフ中に楕円で示した範囲がスラグ組成の目標組成である。 In the present invention, these converter slag and ingot slag are charged into the furnace 1 and adjusted so that the slag basicity (CaO / SiO2) at the end of the de-Si treatment is in the range of 0.5 to 1.8. However, the Si removal treatment is performed. FIG. 2 is an isothermal cross-sectional view at 1300 ° C. of a ternary diagram of SiO 2 —CaO—FeO. The graph shows a straight line with CaO / SiO 2 of 0.5 and a straight line with CaO / SiO 2 of 1.8. As shown in this graph, slag easily forms a liquid phase within this range, and excellent fluidity can be obtained. However, when the basicity is out of this range, the melting point increases. The range indicated by the ellipse in the graph is the target composition of the slag composition.
このように組成調整を行えばスラグの融点は低下し、炉１に投入されたスラグも短時間で溶けることとなる。このため本発明では、融点が約２９３０℃の塊生石灰を投入した従来法のように長時間を要することなく、５分程度で完全溶融させることができる。そこで本発明では溶銑中のＳｉ濃度が０．２％以上の状態で脱Ｓｉスラグのみをスラグパン４に排出する中間排滓を行う。これに対し、塊状生石灰を使用した場合には、５分程度では殆ど溶融しないので中間排滓時のスラグ排出性が著しく悪く、また排出したスラグ中には未反応のＣａＯが多量に残り、スラグを路盤材等に再利用する際、強アルカリ化や膨張の問題の原因となる。また、これを避けるため脱珪処理を長時間行えば、炉のサイクルタイムが長くなって生産性を落とすことになり、また珪素濃度が０．２%以下まで脱珪反応が進行してしまうので、歩留まり悪化が避けられない。Ｓｉ濃度が０．２％以上の状態では未だ銑鉄の脱Ｃ反応は生じないので、脱Ｃ反応により発生したＣＯが溶銑を激しく撹拌するトラブルを回避することができ、脱Ｓｉスラグ中に粒鉄が巻き込まれることもない。またスラグパン４内における粒鉄とスラグが反応することもなくなり、突沸によるスラグの流出も防止することができる。 If the composition is adjusted in this manner, the melting point of the slag is lowered, and the slag charged into the furnace 1 is also melted in a short time. Therefore, in the present invention, it can be completely melted in about 5 minutes without requiring a long time as in the conventional method in which lump lime having a melting point of about 2930 ° C. is added. Therefore, in the present invention, intermediate evacuation is performed in which only the de-Si slag is discharged to the slag pan 4 in a state where the Si concentration in the hot metal is 0.2% or more. On the other hand, when massive quicklime is used, it hardly melts in about 5 minutes, so the slag discharge property at the time of intermediate discharge is extremely bad, and a large amount of unreacted CaO remains in the discharged slag. When reused as a roadbed material, it becomes a cause of problems of strong alkalinization and expansion. In addition, if the desiliconization process is performed for a long time to avoid this, the cycle time of the furnace becomes longer and the productivity is lowered, and the desiliconization reaction proceeds to a silicon concentration of 0.2% or less. Yield deterioration is inevitable. Since the de-C reaction of pig iron does not yet occur when the Si concentration is 0.2% or more, it is possible to avoid the trouble that the CO generated by the de-C reaction stirs the molten iron vigorously, and the granular iron is contained in the de-Si slag. Is not involved. Moreover, the granular iron and slag in the slag pan 4 do not react, and the outflow of slag due to bumping can be prevented.
従って従来のように脱Ｓｉスラグ中に粒鉄が巻き込まれ外部に排出されることもなくなり、溶鋼歩留まりが向上する。図３はそのグラフであり、中間排滓を行わない場合の溶鋼歩留まりを基準（０．０％）として表示している。図３に示すように、溶銑中のＳｉ濃度が０．２％よりも低下するまで脱Ｓｉ処理を行い中間排滓を行うと、巻き込まれた粒鉄が排出されるために溶鋼歩留まりはマイナス０．１４％となるが、本発明のように溶銑中のＳｉ濃度が０．２％以上の段階で中間排滓を行った場合には、プラス０．２８％となる。また、中間排滓を行わない場合に比べて歩留まりが向上するのは、脱Ｐ時に生成するスラグ量が減少し、脱Ｐスラグに巻き込まれてロスする鉄分が減少するためである。 Therefore, the granular iron is not involved in the de-Si slag as in the prior art and is not discharged to the outside, and the molten steel yield is improved. FIG. 3 is a graph showing the yield of molten steel when no intermediate waste is performed as a reference (0.0%). As shown in FIG. 3, when the Si removal treatment is performed until the Si concentration in the hot metal falls below 0.2% and intermediate waste is performed, the entrained granular iron is discharged, so the molten steel yield is minus 0. However, when the intermediate waste is performed when the Si concentration in the hot metal is 0.2% or more as in the present invention, it becomes 0.28%. The reason why the yield is improved as compared with the case where intermediate waste is not performed is that the amount of slag generated at the time of de-P is reduced, and the iron content lost by de-P slag is reduced.
なお中間排滓によるＣａＯ削減効果は既知であるが具体的な平均値を示すと、装入Ｓｉが０．６％の場合には中間排滓なしでは脱Ｓｉ脱Ｐ工程に要するＣａＯが１７ｋｇ/トンであるのに対して、中間排滓を行うと１３ｋｇ/トンまで減少し、装入Ｓｉが０．８％の場合には中間排滓なしでは脱Ｓｉ脱ＰＣａＯが２２ｋｇ/トンであるのに対して、中間排滓を行うと１５ｋｇ/トンまで減少する。 The CaO reduction effect by the intermediate waste is known, but a specific average value shows that when the charged Si is 0.6%, the CaO required for the de-Si removal P step without intermediate waste is 17 kg / In contrast, when the intermediate waste is performed, the amount is reduced to 13 kg / ton. When the charged Si is 0.8%, the Si removal PCaO is 22 kg / ton without the intermediate waste. On the other hand, if the intermediate excretion is performed, it is reduced to 15 kg / ton.
中間排滓により脱Ｓｉスラグを排出した後、再び上吹ランス２から高圧酸素を吹き込んで脱Ｐ処理を行う。この脱Ｐ処理自体は従来と同様であり、このようにして脱Ｓｉと脱Ｐが行われた溶銑は鍋５に移し変えられ、転炉３において脱Ｃ処理が行われる。この工程で発生する転炉スラグは前記したように脱Ｓｉ処理工程に返送される。また造塊スラグも同様に脱Ｓｉ処理工程に返送される。 After removing Si-free slag by intermediate waste, high-pressure oxygen is blown again from the top blowing lance 2 to perform the P removal treatment. The de-P treatment itself is the same as the conventional one, and the hot metal from which de-Si and de-P have been performed in this way is transferred to the pan 5 and de-C treatment is performed in the converter 3. The converter slag generated in this step is returned to the Si removal treatment step as described above. Similarly, the ingot slag is returned to the Si removal treatment process.
上記のように、本発明の精錬工程においてはＣａＯ源として蛍石を使用していないので、発生したスラグは土壌規制に抵触せず、路盤材などとして再利用することができる。 As described above, since fluorite is not used as the CaO source in the refining process of the present invention, the generated slag does not conflict with soil regulations and can be reused as roadbed material.
本発明の効果を確認するため行った実験の結果を表１にまとめた。
Ｎｏ．１〜Ｎｏ．１４は本発明の実施例であり、蛍石を使用せず転炉スラグ及び造塊スラグを用いて、転炉スラグを脱Ｓｉ工程に返送し、Ｓｉ濃度が０．２％〜０．３％である段階で中間排滓を行った例である。脱Ｓｉ脱Ｐ処理後の溶銑中のＳｉ濃度は検出限界以下にまで低減し、Ｐ濃度は０．０１２〜０．０５３％にまで低減している。このときの脱Ｓｉ脱Ｐ処理に要したＣａＯ量は表中に示されるとおりであり、１０.０〜２１．０ｋｇ/トンの範囲にある。なお使用した転炉スラグは、ＣａＯ：４６％、ＳｉＯ２：１４％、ＦｅＯ：２４％、その他：１６％の組成を有するもので、その融点は１３２０℃である。使用した造塊スラグは、ＣａＯ：３４％、ＳｉＯ２：１３％、ＦｅＯ：１２％、その他：４１％の組成を有するもので、その融点は１１５０℃である。
The results of experiments conducted to confirm the effects of the present invention are summarized in Table 1.
No. 1-No. 14 is an example of the present invention, using converter slag and ingot slag without using fluorite, returning the converter slag to the de-Si process, and the Si concentration is 0.2% to 0.3%. This is an example in which intermediate excretion is performed at a certain stage. The Si concentration in the hot metal after the de-Si removal P treatment is reduced below the detection limit, and the P concentration is reduced to 0.012 to 0.053%. The amount of CaO required for the deSi removal P treatment at this time is as shown in the table, and is in the range of 10.0 to 21.0 kg / ton. The converter slag used has a composition of CaO: 46%, SiO 2 : 14%, FeO: 24%, others: 16%, and its melting point is 1320 ° C. The ingot slag used has a composition of CaO: 34%, SiO 2 : 13%, FeO: 12%, and others: 41%, and its melting point is 1150 ° C.
Ｎｏ．１５及びＮｏ．１６に示す比較例１は、脱Ｓｉ処理終了後のスラグ塩基度が０．５を下回った場合である。中間排滓後、処理を開始すると炉口からスラグが激しく流出して処理が困難であった。また、Ｎｏ１７及びＮｏ１８に示す比較例２は、脱Ｓｉ処理終了後のスラグ塩基度が１．８を上回った場合である。塩基度の上昇に伴って中間排滓時のスラグ排出性が悪化した。 No. 15 and no. The comparative example 1 shown in 16 is a case where the slag basicity after completion | finish of Si removal processing is less than 0.5. When the treatment was started after the intermediate evacuation, the slag violently flowed out of the furnace port, making the treatment difficult. Moreover, the comparative example 2 shown to No17 and No18 is a case where the slag basicity after completion | finish of Si removal process exceeded 1.8. As the basicity increased, the slag discharge performance during intermediate drainage deteriorated.
またＮｏ．１９〜Ｎｏ．２２に示す比較例３は、脱Ｓｉ処理終了後の溶銑中のＳｉ濃度が０．２％を下回った場合である。脱Ｓｉ処理終了後の溶銑中のＳｉ濃度が０．１％より低い場合は、脱Ｓｉ中に炉口からスラグが流出した。また中間排滓後のスラグパンからもスラグが流出した。脱Ｓｉ処理終了後の溶銑中のＳｉ濃度が０．１％〜０．２％では、脱Ｓｉ中に炉口からスラグは流出しなくなったものの、中間排滓後のスラグパンからスラグが流出した。 No. 19-No. The comparative example 3 shown in 22 is a case where the Si concentration in the hot metal after completion of the Si removal treatment is less than 0.2%. When the Si concentration in the hot metal after the Si removal treatment was lower than 0.1%, slag flowed out of the furnace port during the Si removal. Slag also flowed out from the slag pan after the intermediate evacuation. When the Si concentration in the hot metal after completion of the Si removal treatment was 0.1% to 0.2%, the slag did not flow out from the furnace port during the Si removal, but the slag flowed out from the slag pan after the intermediate waste.
表１のＮｏ２３〜Ｎｏ２７に示す比較例４は、中間排滓を行わなかった場合である。操業性に支障はないものの、脱Ｓｉ脱Ｐ処理に使用するＣａＯ原単位が悪化した。Ｎｏ２８〜Ｎｏ３２に示す比較例５は、脱Ｓｉ処理時の副原料としてのスラグをリサイクルしなかった場合である。脱Ｓｉ処理時のスラグ形成に時間を要したため、試験的に蛍石を使用した。しかしながら、蛍石を使用しても脱Ｓｉ処理後の溶銑中のＳｉ濃度が０．２％以上で処理を終えることができず、中間排滓後のスラグパンからスラグが流出した。 The comparative example 4 shown to No23-No27 of Table 1 is a case where an intermediate waste was not performed. Although there was no hindrance to operability, the basic unit of CaO used for de-Si de-P treatment deteriorated. The comparative example 5 shown to No28-No32 is a case where the slag as an auxiliary material at the time of Si removal processing was not recycled. Since it took time to form slag during the Si removal treatment, fluorite was used as a test. However, even if fluorite was used, the treatment could not be completed when the Si concentration in the hot metal after the Si removal treatment was 0.2% or more, and the slag flowed out from the slag pan after the intermediate waste.
表２は脱Ｓｉ終了時のスラグ塩基度を変化させて、操業性を調査した結果である。スラグ塩基度は転炉スラグおよび塊生石灰を用いて調整し、溶銑中のＳｉ濃度が０．２５％前後で中間排滓を実施した。スラグ塩基度の値は、投入した副原料量および溶銑成分変化からの計算値である。 Table 2 shows the results of investigating operability by changing the slag basicity at the end of Si removal. Slag basicity was adjusted using converter slag and lump lime, and the intermediate waste was carried out when the Si concentration in the hot metal was around 0.25%. The value of slag basicity is a calculated value from the amount of added auxiliary raw material and the hot metal component change.
中間排滓時のスラグ排出性に注目すると、スラグ塩基度が１．８以下であれば、炉の傾動に応じて飴状のスラグがゆっくりと流出し、スラグがある程度炉外に排出された後で溶銑が流出を始めることが目視で確認できた。これは、短時間で液相率が高いスラグを形成できたためと考えられる。一方、塩基度を１．８以上に調整すると、炉を傾けてもなかなかスラグが排出されず、さらに炉を傾けるとスラグに先んじて溶銑が流出した。これは、塩基度を高めるために多量の転炉スラグおよび塊生石灰を投入する必要が生じたため短時間では溶解しきらず、液相率が低いスラグになっていたためと考えられる。スラグが炉外に排出できないと、Ｓｉの炉外除去効果が得られず、脱Ｐ時のＣａＯ使用量を低減することができないので、脱Ｓｉスラグの塩基度を１．８以下に調整することが望ましい。 Paying attention to the slag discharge performance during intermediate discharge, if the slag basicity is 1.8 or less, the bowl-shaped slag slowly flows out according to the tilt of the furnace, and after the slag is discharged to the outside to some extent It was confirmed visually that the hot metal began to flow out. This is considered because slag with a high liquid phase rate was able to be formed in a short time. On the other hand, when the basicity was adjusted to 1.8 or more, slag was not easily discharged even when the furnace was tilted, and when the furnace was further tilted, hot metal flowed out prior to the slag. This is thought to be because a large amount of converter slag and bulk lime were required to be added in order to increase the basicity, so that it was not completely dissolved in a short time and the liquid phase rate was low. If the slag cannot be discharged outside the furnace, the effect of removing Si out of the furnace cannot be obtained, and the amount of CaO used during de-P cannot be reduced, so the basicity of de-Si slag should be adjusted to 1.8 or less. Is desirable.
一方、中間排滓後の脱Ｐ処理状況に注目すると、スラグ塩基度が０．５以上であれば特に問題なく操業できたのに対し、塩基度が０．５以下だと、脱Ｐのために酸素供給を開始してしばらくすると炉口から激しくスラグが流出して、処理を継続できなくなった。これは、脱Ｓｉスラグの塩基度が低いほどスラグの粘度は高くなるため、脱Ｓｉスラグの塩基度が低すぎると、酸素供給による脱Ｃで生じたＣＯガスがスラグを通過できず、炉口までスラグを押し上げてしまったためと考えられる。脱Ｐ処理の操業性のためには脱Ｓｉスラグの塩基度を０．５以上に調整することが望ましい。 On the other hand, when attention is paid to the de-P treatment status after the intermediate evacuation, the slag basicity can be operated without any problems if the basicity is 0.5 or more, whereas if the basicity is 0.5 or less, de-P After a while after the oxygen supply was started, slag spilled violently from the furnace port and the treatment could not be continued. This is because the lower the basicity of the de-Si slag, the higher the viscosity of the slag, so if the basicity of the de-Si slag is too low, the CO gas generated by de-C by oxygen supply cannot pass through the slag, This is probably because the slag has been pushed up. For the operability of the de-P treatment, it is desirable to adjust the basicity of the de-Si slag to 0.5 or more.
以上２点より、脱Ｓｉスラグの塩基度は０．５〜１．８の範囲に調整するのが望ましいことを確認した。 From the above two points, it was confirmed that the basicity of the de-Si slag is preferably adjusted in the range of 0.5 to 1.8.
表３は、脱Ｓｉ後の溶銑[Ｓｉ]に応じて操業性がどのように変化するか試験結果を示したものである。溶銑[Ｓｉ]＜０．１０％まで脱Ｓｉした後に排滓を試みた場合、脱Ｓｉ処理中の炉口からのスラグ流出および中間排滓後のスラグパンからのスラグ漏出が激しく、操業性は非常に悪かった。溶銑[Ｓｉ]＝０．１０〜０．２０％の範囲まで脱Ｓｉした後に排滓を試みると、脱Ｓｉ処理中の炉口からのスラグ流出は起こらなくなったが、中間排滓後のスラグパンからのスラグ漏出は引き続き起こり、操業性は悪かった。一方、溶銑[Ｓｉ]＞０．２０％の範囲で中間排滓を行うと中間排滓後のスラグパンからのスラグ漏出も起こらなくなり、操業性が改善された。脱Ｓｉ時の塩基度調整に用いた副原料の種類と中間排滓時のスラグ排出性の関係を調査すると、溶銑[Ｓｉ]＜０．２０％であれば使用する副原料の種類によらずスラグ排出性は良好であったが、溶銑[Ｓｉ]＞０．２０％になると生石灰および蛍石を使用した場合にはスラグ排出性が悪く、炉外にＳｉを排出できないため、中間排滓によるＣａＯ削減効果が得られなくなってしまった。一方、本発明により転炉スラグあるいは造塊スラグを用いた場合には、溶銑[Ｓｉ]＞０．２０％の領域でもスラグ排出性は良好であり、ＣａＯ削減効果が享受できた。 Table 3 shows the test results on how the operability changes depending on the hot metal [Si] after de-Si. When evacuation is attempted after de-Si removal to hot metal [Si] <0.10%, slag outflow from the furnace port during de-Si treatment and slag leakage from the slag pan after intermediate evacuation are severe, and operability is very high It was bad. When evacuation was attempted after desiliconization to a range of hot metal [Si] = 0.10 to 0.20%, slag outflow from the furnace port during desiliconization treatment did not occur. The slag leakage continued and the operability was poor. On the other hand, when intermediate waste was performed in the range of hot metal [Si]> 0.20%, slag leakage from the slag pan after intermediate waste did not occur, and operability was improved. Investigating the relationship between the type of auxiliary material used for basicity adjustment at the time of de-Si and the slag discharging property at the time of intermediate waste, if hot metal [Si] <0.20%, regardless of the type of auxiliary material used Slag discharge was good, but when hot metal [Si]> 0.20%, when using quicklime and fluorite, slag discharge is poor and Si cannot be discharged outside the furnace. The CaO reduction effect can no longer be obtained. On the other hand, when converter slag or ingot slag was used according to the present invention, slag discharge was good even in the hot metal [Si]> 0.20% region, and a CaO reduction effect could be enjoyed.
１ 炉
２ 上吹ランス
３ 転炉
４ スラグパン
５ 鍋
1 furnace 2 top blowing lance 3 converter 4 slag pan 5 pan
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009296860A JP5487959B2 (en) | 2009-12-28 | 2009-12-28 | Hot metal removal Si removal P treatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009296860A JP5487959B2 (en) | 2009-12-28 | 2009-12-28 | Hot metal removal Si removal P treatment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2011137196A true JP2011137196A (en) | 2011-07-14 |
| JP5487959B2 JP5487959B2 (en) | 2014-05-14 |
Family
ID=44348889
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2009296860A Active JP5487959B2 (en) | 2009-12-28 | 2009-12-28 | Hot metal removal Si removal P treatment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5487959B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013012039A1 (en) * | 2011-07-19 | 2013-01-24 | Ｊｆｅスチール株式会社 | Method for smelting molten pig iron |
| WO2013108810A1 (en) * | 2012-01-19 | 2013-07-25 | Ｊｆｅスチール株式会社 | Method for preliminary treatment of molten iron |
| JP2013189714A (en) * | 2012-01-19 | 2013-09-26 | Jfe Steel Corp | Method for preliminary treatment of molten iron |
| JP2013227664A (en) * | 2012-03-26 | 2013-11-07 | Jfe Steel Corp | Molten iron preliminary treatment method |
| WO2014112432A1 (en) * | 2013-01-18 | 2014-07-24 | Ｊｆｅスチール株式会社 | Converter steelmaking process |
| JP2015017323A (en) * | 2013-06-14 | 2015-01-29 | Ｊｆｅスチール株式会社 | Preliminary treatment method for molten iron |
| KR20170078818A (en) * | 2014-12-16 | 2017-07-07 | 제이에프이 스틸 가부시키가이샤 | Molten iron pre-treatment method |
| WO2018135347A1 (en) * | 2017-01-23 | 2018-07-26 | 新日鐵住金株式会社 | Method for suppressing foaming of slag, and converter refining method |
| WO2022195951A1 (en) | 2021-03-17 | 2022-09-22 | Ｊｆｅスチール株式会社 | Method for operating converter furnace, and method for producing molten steel |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04214810A (en) * | 1990-12-14 | 1992-08-05 | Sumitomo Metal Ind Ltd | Treatment of molten iron |
| JPH059533A (en) * | 1991-07-01 | 1993-01-19 | Sumitomo Metal Ind Ltd | Method for treating molten iron |
| JPH059534A (en) * | 1991-07-04 | 1993-01-19 | Kawasaki Steel Corp | Method for pretreating molten iron |
| JPH11323420A (en) * | 1998-05-15 | 1999-11-26 | Nippon Steel Corp | Pretreating method for molten iron |
| JP2004190101A (en) * | 2002-12-12 | 2004-07-08 | Nippon Steel Corp | Method for pre-treating molten iron |
| JP2006328453A (en) * | 2005-05-24 | 2006-12-07 | Kobe Steel Ltd | Method for desiliconizing molten iron |
-
2009
- 2009-12-28 JP JP2009296860A patent/JP5487959B2/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04214810A (en) * | 1990-12-14 | 1992-08-05 | Sumitomo Metal Ind Ltd | Treatment of molten iron |
| JPH059533A (en) * | 1991-07-01 | 1993-01-19 | Sumitomo Metal Ind Ltd | Method for treating molten iron |
| JPH059534A (en) * | 1991-07-04 | 1993-01-19 | Kawasaki Steel Corp | Method for pretreating molten iron |
| JPH11323420A (en) * | 1998-05-15 | 1999-11-26 | Nippon Steel Corp | Pretreating method for molten iron |
| JP2004190101A (en) * | 2002-12-12 | 2004-07-08 | Nippon Steel Corp | Method for pre-treating molten iron |
| JP2006328453A (en) * | 2005-05-24 | 2006-12-07 | Kobe Steel Ltd | Method for desiliconizing molten iron |
Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101606255B1 (en) * | 2011-07-19 | 2016-03-24 | 제이에프이 스틸 가부시키가이샤 | Method of refining molten iron |
| WO2013012039A1 (en) * | 2011-07-19 | 2013-01-24 | Ｊｆｅスチール株式会社 | Method for smelting molten pig iron |
| US9315875B2 (en) | 2011-07-19 | 2016-04-19 | Jfe Steel Corporation | Method of refining molten iron |
| JP2013231237A (en) * | 2011-07-19 | 2013-11-14 | Jfe Steel Corp | Method for smelting molten iron |
| JP5418733B2 (en) * | 2011-07-19 | 2014-02-19 | Ｊｆｅスチール株式会社 | Hot metal refining method |
| CN103649341A (en) * | 2011-07-19 | 2014-03-19 | 杰富意钢铁株式会社 | Method for smelting molten pig iron |
| JP2013167015A (en) * | 2012-01-19 | 2013-08-29 | Jfe Steel Corp | Method for preliminary treatment of molten iron |
| US9920390B2 (en) | 2012-01-19 | 2018-03-20 | Jfe Steel Corporation | Method for preliminary treatment of molten iron |
| JP2013189714A (en) * | 2012-01-19 | 2013-09-26 | Jfe Steel Corp | Method for preliminary treatment of molten iron |
| WO2013108810A1 (en) * | 2012-01-19 | 2013-07-25 | Ｊｆｅスチール株式会社 | Method for preliminary treatment of molten iron |
| JP2013227664A (en) * | 2012-03-26 | 2013-11-07 | Jfe Steel Corp | Molten iron preliminary treatment method |
| WO2014112432A1 (en) * | 2013-01-18 | 2014-07-24 | Ｊｆｅスチール株式会社 | Converter steelmaking process |
| JP5954551B2 (en) * | 2013-01-18 | 2016-07-20 | Ｊｆｅスチール株式会社 | Converter steelmaking |
| JP2015017323A (en) * | 2013-06-14 | 2015-01-29 | Ｊｆｅスチール株式会社 | Preliminary treatment method for molten iron |
| KR20170078818A (en) * | 2014-12-16 | 2017-07-07 | 제이에프이 스틸 가부시키가이샤 | Molten iron pre-treatment method |
| KR101896429B1 (en) | 2014-12-16 | 2018-09-07 | 제이에프이 스틸 가부시키가이샤 | Hot metal pretreatment method |
| WO2018135347A1 (en) * | 2017-01-23 | 2018-07-26 | 新日鐵住金株式会社 | Method for suppressing foaming of slag, and converter refining method |
| CN110023517A (en) * | 2017-01-23 | 2019-07-16 | 日本制铁株式会社 | Inhibit the method and converter refining method of clinker foaming |
| JPWO2018135347A1 (en) * | 2017-01-23 | 2019-11-07 | 日本製鉄株式会社 | Slag forming suppression method and converter refining method |
| WO2022195951A1 (en) | 2021-03-17 | 2022-09-22 | Ｊｆｅスチール株式会社 | Method for operating converter furnace, and method for producing molten steel |
| KR20230155562A (en) | 2021-03-17 | 2023-11-10 | 제이에프이 스틸 가부시키가이샤 | Converter operation method and molten steel manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5487959B2 (en) | 2014-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5487959B2 (en) | Hot metal removal Si removal P treatment method | |
| WO2013108810A1 (en) | Method for preliminary treatment of molten iron | |
| JP5343308B2 (en) | Desulfurization method for molten steel | |
| JP4736466B2 (en) | Method for producing high chromium molten steel | |
| JP6945055B2 (en) | Method of slag in the production process of ultra-low phosphorus steel and method of production of ultra-low phosphorus steel | |
| JP6421634B2 (en) | Manufacturing method of molten steel | |
| JP2006274349A (en) | Method for refining steel | |
| JP4743078B2 (en) | Method for improving slag evacuation after dephosphorization and method for dephosphorizing hot metal using the slag | |
| JP4977870B2 (en) | Steel making method | |
| CN113005261A (en) | Comprehensive deoxidation and desulfurization process for smelting stainless steel by using small-capacity AOD furnace | |
| JP5967139B2 (en) | Hot metal pretreatment method | |
| JP4743072B2 (en) | Method for improving slag evacuation after dephosphorization and method for dephosphorizing hot metal using the slag | |
| JP4581751B2 (en) | Prevention of dust from hot metal transport container | |
| JP2002241829A (en) | Desiliconizing method for molten iron | |
| JP3158912B2 (en) | Stainless steel refining method | |
| JPH08176644A (en) | Manufacture of low sulfur steel with reduced killing time | |
| EP1524322A2 (en) | Method of liquid steel production with slag recycling in a converter, equipment to employ the method | |
| JP3419254B2 (en) | Hot metal dephosphorization method | |
| JP5333423B2 (en) | Hot metal dephosphorization method | |
| JP4224197B2 (en) | Hot metal dephosphorization method with high reaction efficiency | |
| RU2186124C2 (en) | Method of pig iron conversion | |
| KR101045970B1 (en) | Converter refining method to control high end carbon | |
| KR100862799B1 (en) | Method for Preventing Slag Inclusion in Converter Steel Tapping | |
| JP2005200762A (en) | Method for desulfurizing molten pig iron | |
| RU2152442C1 (en) | Method of treatment of molten steel with slag |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20120209 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20131018 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20131206 |
|
| 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: 20140128 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20140210 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 5487959 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |