JP2002161310A - Desulfurization process for liquid steel using rh vacuum degassing equipment - Google Patents
Desulfurization process for liquid steel using rh vacuum degassing equipmentInfo
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- JP2002161310A JP2002161310A JP2000355477A JP2000355477A JP2002161310A JP 2002161310 A JP2002161310 A JP 2002161310A JP 2000355477 A JP2000355477 A JP 2000355477A JP 2000355477 A JP2000355477 A JP 2000355477A JP 2002161310 A JP2002161310 A JP 2002161310A
- Authority
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- Japan
- Prior art keywords
- desulfurizing agent
- desulfurization
- molten steel
- carrier gas
- rate
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＲＨ真空脱ガス装
置において、溶鋼中硫黄を効率良く除去することのでき
る脱硫方法に関するものである。The present invention relates to a desulfurization method capable of efficiently removing sulfur in molten steel in an RH vacuum degassing apparatus.
【０００２】[0002]
【従来の技術】硫黄含有量が１０ｐｐｍ以下程度に低
い、ラインパイプ材等の所謂極低硫鋼を溶製するために
は、溶銑段階で行なう脱硫（溶銑脱硫という）と、溶鋼
段階で行なう脱硫（溶鋼脱硫という）とが必要である。
このうち溶鋼脱硫は、一般に、取鍋に受けた溶鋼中に脱
硫剤をキャリアガスと共に吹き込むインジェクション法
により行なわれるが、脱硫処理以外に脱ガス処理や脱炭
処理が必要な鋼種では、脱硫処理の前工程又は後工程
で、減圧下での精錬が可能なＲＨ真空脱ガス装置にて処
理する必要があり、これら脱硫処理や脱ガス処理等の二
次精錬工程を簡素化するため、ＲＨ真空脱ガス装置にて
脱硫する方法が多数提案されている。2. Description of the Related Art In order to produce so-called ultra-low sulfur steel such as line pipe materials having a sulfur content of about 10 ppm or less, desulfurization performed in a hot metal stage (called hot metal desulfurization) and desulfurization performed in a molten steel stage are performed. (Referred to as molten steel desulfurization).
Of these, molten steel desulfurization is generally performed by an injection method in which a desulfurizing agent is blown together with a carrier gas into molten steel received in a ladle, but for steel types that require degassing or decarburization in addition to desulfurization, In the pre-process or post-process, it is necessary to perform treatment with an RH vacuum degassing device capable of refining under reduced pressure. To simplify the secondary refining process such as desulfurization and degassing, RH vacuum degassing is performed. Many methods for desulfurization with a gas device have been proposed.
【０００３】例えば、特公昭６１−５９３７５号公報に
は、ＲＨ真空脱ガス装置の上昇側浸漬管の下方に配置し
た吹き込みランスから、微粉状脱硫剤をキャリアガスと
共に溶鋼の上昇流中に吹き込む方法が開示されており、
又、特開昭６１−１３０４１３号公報には、ＲＨ真空脱
ガス装置の真空槽下部の溶鋼湯面下に設けた羽口から、
粉状脱硫剤をキャリアガスと共に吹き込む方法が開示さ
れている。そして、脱硫剤としては、例えば特公平１−
４９７７２号公報に開示されたように、低融点のＣａＯ
−ＣａＦ2 系脱硫剤が一般に使用されている。[0003] For example, Japanese Patent Publication No. 61-59375 discloses a method of blowing a fine powdery desulfurizing agent together with a carrier gas into a rising flow of molten steel from a blowing lance disposed below a rising immersion pipe of an RH vacuum degassing apparatus. Is disclosed,
Japanese Patent Application Laid-Open No. Sho 61-130413 discloses a tuyere provided below the surface of molten steel below the vacuum chamber of an RH vacuum degassing apparatus.
A method of blowing a powdery desulfurizing agent together with a carrier gas is disclosed. And as the desulfurizing agent, for example,
No. 49772 discloses a low melting point CaO.
-CaF 2 based desulfurizing agent is generally used.
【０００４】[0004]
【発明が解決しようとする課題】ＲＨ真空脱ガス装置に
おいては、真空槽内では攪拌力が強く、添加した脱硫剤
と溶鋼とは強攪拌されるが、取鍋内では攪拌力が弱く、
溶鋼上に浮遊する取鍋内スラグ位置に浮上した脱硫剤と
溶鋼との反応は極めて遅い。そのため、ＲＨ真空脱ガス
装置でインジェクション法により脱硫する際には、脱硫
剤が取鍋内スラグ位置に浮上した後の脱硫反応、所謂パ
ーマネント反応は期待できず、吹き込まれた脱硫剤が取
鍋内の溶鋼湯面上に浮上するまでのトランジトリー反応
のみで効率良く脱硫しなければならない。In the RH vacuum degassing apparatus, the stirring force is strong in the vacuum chamber and the added desulfurizing agent and the molten steel are strongly stirred, but in the ladle, the stirring force is weak.
The reaction between the desulfurizing agent floating at the slag position in the ladle floating on the molten steel and the molten steel is extremely slow. Therefore, when desulfurization is performed by the RH vacuum degassing apparatus by the injection method, a desulfurization reaction after the desulfurization agent has floated to the slag position in the ladle, a so-called permanent reaction, cannot be expected, and the injected desulfurization agent is in the ladle. It must be efficiently desulfurized only by a transient reaction until it floats on the surface of molten steel.
【０００５】本発明者等は、上記従来技術に沿って、脱
硫剤吹き込み速度及びキャリアガス流量を変更した試験
操業を実施した。その結果、脱硫剤吹き込み速度及びキ
ャリアガス流量の変更に伴い、トランジトリー反応が左
右され、脱硫率が大きく変動することを確認すると共
に、高脱硫率を得るためには、これらの条件を制御する
ことが極めて重要であることが分かった。しかしなが
ら、上記従来技術は、脱硫剤吹き込み速度及びキャリア
ガス流量の脱硫率に及ぼす影響については、何ら開示し
ていない。The present inventors conducted a test operation in which the blowing rate of the desulfurizing agent and the flow rate of the carrier gas were changed in accordance with the above-mentioned conventional technology. As a result, with the change of the desulfurizing agent blowing rate and the carrier gas flow rate, the transit reaction is influenced and the desulfurization rate is confirmed to fluctuate greatly, and these conditions are controlled to obtain a high desulfurization rate. Turned out to be extremely important. However, the above-mentioned prior art does not disclose any influence of the blowing rate of the desulfurizing agent and the flow rate of the carrier gas on the desulfurization rate.
【０００６】本発明は上記事情に鑑みなされたもので、
その目的とするところは、ＲＨ真空脱ガス装置において
インジェクション法により溶鋼の脱硫を行なう際に、安
定した高脱硫率で、効率良く脱硫することのできる脱硫
方法を提供することである。The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a desulfurization method capable of efficiently performing desulfurization with a stable high desulfurization rate when desulfurizing molten steel by an injection method in an RH vacuum degassing apparatus.
【０００７】[0007]
【課題を解決するための手段】本発明によるＲＨ真空脱
ガス装置での溶鋼の脱硫方法は、粉状の脱硫剤をキャリ
アガスと共に溶鋼中に吹き込み、吹き込んだ脱硫剤と溶
鋼とをＲＨ真空脱ガス装置の真空槽内で混合して脱硫す
る溶鋼の脱硫方法において、前記脱硫剤の吹き込み速度
を１００ｋｇ／ｍｉｎ以下とし、且つ、前記キャリアガ
スの流量を２０００Ｎｌ／ｍｉｎ以上とすることを特徴
とするものである。The method for desulfurizing molten steel in an RH vacuum degassing apparatus according to the present invention comprises blowing a powdery desulfurizing agent together with a carrier gas into molten steel, and subjecting the blown desulfurizing agent and the molten steel to RH vacuum degassing. A method for desulfurizing molten steel mixed and desulfurized in a vacuum chamber of a gas apparatus, wherein the blowing speed of the desulfurizing agent is 100 kg / min or less, and the flow rate of the carrier gas is 2000 Nl / min or more. Things.
【０００８】本発明者等は、ＲＨ真空脱ガス装置におい
てインジェクション法により効率良く脱硫するための条
件を種々検討した。その結果、吹き込まれた脱硫剤の一
部は、脱硫反応に関与せず、キャリアガスに捕捉された
まま溶鋼中から離脱し、排ガス中に混じって真空槽から
排出されてしまい、これが脱硫率低下の主たる原因であ
ることを確認した。そして、この脱硫反応に関与せずに
真空槽から排出される脱硫剤の量は、脱硫剤吹き込み速
度とキャリアガス流量とに関係することが分かった。The present inventors have studied various conditions for efficient desulfurization by an injection method in an RH vacuum degassing apparatus. As a result, some of the injected desulfurization agent does not participate in the desulfurization reaction, escapes from the molten steel while being trapped by the carrier gas, mixes with the exhaust gas, and is discharged from the vacuum chamber, which lowers the desulfurization rate. The main cause was confirmed. Then, it was found that the amount of the desulfurizing agent discharged from the vacuum chamber without being involved in the desulfurization reaction was related to the blowing speed of the desulfurizing agent and the flow rate of the carrier gas.
【０００９】即ち、脱硫剤の吹き込み速度を１００ｋｇ
／ｍｉｎ以下に抑えると共に、キャリアガスの流量を２
０００Ｎｌ／ｍｉｎ以上とすることで、キャリアガスに
捕捉されたまま排出される脱硫剤が減少し、脱硫反応に
関与する脱硫剤が実質的に多くなり、脱硫反応が促進さ
れて高い脱硫率を得ることができる。尚、理論的には脱
硫剤吹き込み速度の下限は特にないが、工業的な実操業
としては２０ｋｇ／ｍｉｎ以上とすることが好ましい。That is, the blowing speed of the desulfurizing agent is 100 kg.
/ Min or less and the carrier gas flow rate is 2
By setting the concentration to 000 Nl / min or more, the desulfurizing agent discharged while being captured by the carrier gas decreases, the desulfurizing agent involved in the desulfurizing reaction substantially increases, and the desulfurizing reaction is accelerated to obtain a high desulfurization rate. be able to. Note that, theoretically, there is no lower limit of the desulfurizing agent blowing rate, but it is preferable to set the rate to 20 kg / min or more for industrial practical operation.
【００１０】又、キャリアガス流量を２０００Ｎｌ／ｍ
ｉｎ以上とすることで、真空槽内は強攪拌され、脱硫剤
が溶鋼中に均一に分散され、脱硫反応が促進される。
尚、キャリアガス流量の上限は特に規定されるものでは
ないが、キャリアガス流量を多くしても効果は飽和する
ので、工業的な実操業としては５０００Ｎｌ／ｍｉｎ以
下とするのが好ましく、３０００Ｎｌ／ｍｉｎ以下でも
充分である。Further, the flow rate of the carrier gas is set to 2000 Nl / m
By setting to in or more, the inside of the vacuum chamber is vigorously stirred, the desulfurizing agent is uniformly dispersed in the molten steel, and the desulfurization reaction is promoted.
The upper limit of the flow rate of the carrier gas is not particularly limited, but the effect is saturated even if the flow rate of the carrier gas is increased. Therefore, it is preferable that the flow rate be 5000 Nl / min or less in an actual industrial operation, and 3000 Nl / min or less. Min or less is sufficient.
【００１１】[0011]
【発明の実施の形態】以下、本発明を図面に基づき説明
する。図１は、本発明を実施したＲＨ真空脱ガス装置の
縦断面概略図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus embodying the present invention.
【００１２】図１に示すように、ＲＨ真空脱ガス装置１
は、上部槽７及び下部槽８からなる真空槽６と、下部槽
８の下部に設けた上昇側浸漬管９及び下降側浸漬管１０
とで、その基部が構成されている。上部槽７には、原料
投入口１４と、排気装置（図示せず）と接続するダクト
１５とが設けられ、又、上昇側浸漬管９にはＡｒ吹き込
み管１１と、脱硫剤５を収納するホッパー１３に連結し
た脱硫剤吹き込み管１２とが設けられている。Ａｒ吹き
込み管１１からは環流用Ａｒが上昇側浸漬管９内に吹き
込まれ、又、脱硫剤吹き込み管１２からはＡｒ等の不活
性ガスをキャリアガスとして脱硫剤５が上昇側浸漬管９
内に吹き込まれる構造となっている。As shown in FIG. 1, an RH vacuum degassing apparatus 1
Are a vacuum tank 6 composed of an upper tank 7 and a lower tank 8, and an ascending-side immersion pipe 9 and a descending-side immersion pipe 10 provided below the lower tank 8.
Thus, the base is formed. The upper tank 7 is provided with a raw material input port 14 and a duct 15 connected to an exhaust device (not shown), and the rising side immersion pipe 9 stores the Ar blowing pipe 11 and the desulfurizing agent 5. A desulfurizing agent blowing pipe 12 connected to the hopper 13 is provided. Ar for reflux is blown into the rising side immersion pipe 9 from the Ar blowing pipe 11, and the desulfurizing agent 5 is flown from the desulfurizing agent blowing pipe 12 by using an inert gas such as Ar as a carrier gas.
It has a structure that is blown into the interior.
【００１３】このような構成のＲＨ真空脱ガス装置１に
おける本発明の適用方法を以下に説明する。先ず、転炉
や電気炉等で溶銑を脱炭精錬して溶鋼３を得、こうして
得た溶鋼３を収納する取鍋２を真空槽６の直下に搬送す
る。取鍋２内には脱炭精錬時のスラグ４が一部混入し、
溶鋼３の湯面を覆っている。尚、脱炭精錬に使用する溶
銑は予め溶銑脱硫されたものである。又、出鋼後、取鍋
２内にＣａＯ系のフラックスを添加し、スラグ４の組成
を脱硫反応に適したＣａＯを主成分とする組成としても
良い。An application method of the present invention in the RH vacuum degassing apparatus 1 having such a configuration will be described below. First, the molten iron is decarburized and refined in a converter or an electric furnace to obtain molten steel 3, and the ladle 2 containing the molten steel 3 thus obtained is transported directly below the vacuum tank 6. The slag 4 from the decarburization refining is partially mixed in the ladle 2,
It covers the surface of molten steel 3. The hot metal used for the decarburization refining is hot metal desulfurized in advance. After tapping, a CaO-based flux may be added into the ladle 2 so that the composition of the slag 4 may be a composition mainly composed of CaO suitable for the desulfurization reaction.
【００１４】次いで、昇降装置（図示せず）にて取鍋２
を上昇させ、上昇側浸漬管９及び下降側浸漬管１０を取
鍋２内の溶鋼３に浸漬させる。そして、Ａｒ吹き込み管
１１から上昇側浸漬管９内にＡｒを吹き込むと共に、真
空槽６内を排気装置にて排気して真空槽６内を減圧す
る。真空槽６内が減圧されると、取鍋２内の溶鋼３は、
Ａｒ吹き込み管１１から吹き込まれるＡｒと共に上昇側
浸漬管９を上昇して真空槽６内に流入し、その後、下降
側浸漬管１０を介して取鍋２に戻る流れ、所謂、環流を
形成してＲＨ真空脱ガス精錬が施される。Next, the ladle 2 is moved by a lifting device (not shown).
Is raised, and the ascending-side immersion pipe 9 and the descending-side immersion pipe 10 are immersed in the molten steel 3 in the ladle 2. Then, Ar is blown into the rising side immersion pipe 9 from the Ar blowing pipe 11, and the inside of the vacuum chamber 6 is evacuated by an exhaust device to reduce the pressure in the vacuum chamber 6. When the pressure in the vacuum chamber 6 is reduced, the molten steel 3 in the ladle 2
With the Ar blown from the Ar blowing pipe 11, the rising side immersion pipe 9 rises and flows into the vacuum chamber 6, and then returns to the ladle 2 via the descending side immersion pipe 10, forming a so-called reflux. RH vacuum degassing refining is performed.
【００１５】溶鋼３中に溶解酸素が存在すると脱硫反応
が進行しないので、脱硫処理の前に、原料投入口１４か
ら金属Ａｌを投入して溶鋼３を予め脱酸する。金属Ａｌ
の添加量は、脱酸後の溶鋼中のＡｌ濃度が０．０１mass
％以上確保される量とする。尚、出鋼時に取鍋２内に金
属Ａｌを添加し、予め脱酸しても良い。そして、脱酸
後、ホッパー１３内の脱硫剤５をキャリアガスを介して
溶鋼３中に吹き込む。吹き込まれた脱硫剤５は、環流す
る溶鋼３と共に真空槽６内に流入し、次いで、下降側浸
漬管１０を通り取鍋２内に至り、やがて取鍋２内で浮上
してスラグ４位置に到達する。その間に、脱硫剤５は溶
鋼３と反応して溶鋼３を脱硫する。その際、脱硫剤５の
吹き込み速度を１００ｋｇ／ｍｉｎ以下に調整すると共
に、キャリアガスの流量を２０００Ｎｌ／ｍｉｎ以上に
調整する。尚、キャリアガス流量の上限は特にないが、
上昇側浸漬管９の損耗量を少なくするために５０００Ｎ
ｌ／ｍｉｎ以下とすることが望ましい。If the molten oxygen is present in the molten steel 3, the desulfurization reaction does not proceed. Therefore, before the desulfurization treatment, metal Al is charged from the raw material inlet 14 to deoxidize the molten steel 3 in advance. Metal Al
The addition amount of Al is 0.01 mass in the molten steel after deoxidation.
% Or more. In addition, you may add metal Al in the ladle 2 at the time of tapping, and may deoxidize beforehand. After the deoxidation, the desulfurizing agent 5 in the hopper 13 is blown into the molten steel 3 via a carrier gas. The blown desulfurizing agent 5 flows into the vacuum chamber 6 together with the circulating molten steel 3, then reaches the ladle 2 through the descending dipping tube 10, and eventually floats in the ladle 2 to the slag 4 position. To reach. Meanwhile, the desulfurizing agent 5 reacts with the molten steel 3 to desulfurize the molten steel 3. At that time, the blowing speed of the desulfurizing agent 5 is adjusted to 100 kg / min or less, and the flow rate of the carrier gas is adjusted to 2000 Nl / min or more. Although there is no particular upper limit for the carrier gas flow rate,
5000N to reduce the amount of wear on the ascending side immersion pipe 9
1 / min or less is desirable.
【００１６】使用する脱硫剤５は慣用のＣａＯを主成分
とする粉状のフラックスとし、脱硫剤５の添加量は、溶
鋼トン当り３．０ｋｇ（以下、「ｋｇ／ｔ」と記す）以
上とすることが好ましい。３．０ｋｇ／ｔ未満では、脱
硫剤５が不足して目的とするレベルまで脱硫できないこ
とがある。又、脱硫剤５の添加量の上限は特にないが、
脱硫剤５のコスト削減や脱硫剤５の添加による溶鋼３の
温度降下を防止するため、１０．０ｋｇ／ｔ以下とする
ことが好ましい。尚、脱硫処理中の真空槽６内の圧力は
１３３０Ｐａ以下に保持する。１３３０Ｐａ以下であれ
ば吹き込まれた脱硫剤５に含まれる水素による溶鋼３の
水素ピックアップもなく、製品特性上の劣化を招くこと
がないからである。The desulfurizing agent 5 to be used is a conventional powdery flux containing CaO as a main component, and the amount of the desulfurizing agent 5 to be added is 3.0 kg per ton of molten steel (hereinafter, referred to as “kg / t”). Is preferred. If the rate is less than 3.0 kg / t, the desulfurizing agent 5 may be insufficient and desulfurization may not be performed to a target level. Although there is no particular upper limit on the amount of desulfurizing agent 5,
In order to reduce the cost of the desulfurizing agent 5 and to prevent the temperature of the molten steel 3 from dropping due to the addition of the desulfurizing agent 5, the temperature is preferably set to 10.0 kg / t or less. In addition, the pressure in the vacuum chamber 6 during the desulfurization treatment is maintained at 1330 Pa or less. If the pressure is 1330 Pa or less, there is no hydrogen pickup of the molten steel 3 by the hydrogen contained in the blown desulfurizing agent 5 and no deterioration in product characteristics is caused.
【００１７】そして、所定量の脱硫剤５の添加完了後、
必要に応じて溶鋼３の成分調整を行い、次いで、真空槽
６内を大気圧に戻してＲＨ真空脱ガス精錬を終了する。
その後、取鍋２を次工程の連続鋳造設備等の鋳造設備に
搬出して溶鋼３を鋳造する。尚、脱炭処理を行なう際に
は、金属Ａｌを添加する前の溶鋼３が未脱酸の状態で行
なうこととする。After completion of the addition of the predetermined amount of the desulfurizing agent 5,
If necessary, the components of the molten steel 3 are adjusted, and then the inside of the vacuum chamber 6 is returned to the atmospheric pressure to complete the RH vacuum degassing refining.
Thereafter, the ladle 2 is carried out to a casting facility such as a continuous casting facility in the next step, and the molten steel 3 is cast. In addition, when performing a decarburization process, it is assumed that the molten steel 3 before adding the metal Al is not deoxidized.
【００１８】このようにして溶鋼３を脱硫することで、
キャリアガスに捕捉されたまま排気装置にて吸引される
脱硫剤５が減少して、脱硫反応に関与する脱硫剤が実質
的に増加するので、安定した高い脱硫率で脱硫処理を行
なうことができる。又、脱硫処理と同時に溶鋼３の脱ガ
ス処理も行なわれ、二次精錬工程が簡素化される。By desulfurizing the molten steel 3 in this way,
Since the desulfurizing agent 5 sucked by the exhaust device while being trapped by the carrier gas decreases and the desulfurizing agent involved in the desulfurization reaction substantially increases, the desulfurization treatment can be performed at a stable and high desulfurization rate. . Further, simultaneously with the desulfurization treatment, the degassing treatment of the molten steel 3 is also performed, thereby simplifying the secondary refining process.
【００１９】尚、上記説明では、上昇側浸漬管９に設け
た脱硫剤吹き込み管１２を介して脱硫剤５を吹き込んで
いるが、脱硫剤５の添加方法はこの方法に限るものでは
なく、上昇側浸漬管９の下方に吹き込みランスを設け、
この吹き込みランスから上昇側浸漬管９に流入する溶鋼
３中に吹き込んでも、又、下部槽８内の溶鋼３の湯面下
に吹き込み管を設け、この吹き込み管から真空槽６内の
溶鋼３中に吹き込んでも良い。要は、キャリアガスと共
に吹き込む方法であれば、吹き込む位置はどこであって
も本発明を適用できる。又、脱硫剤吹き込み管１２の個
数も１本に限るものではなく、複数本であっても本発明
を適用することができる。In the above description, the desulfurizing agent 5 is blown through the desulfurizing agent blowing pipe 12 provided in the rising side immersion pipe 9, but the method of adding the desulfurizing agent 5 is not limited to this method. A blowing lance is provided below the side immersion pipe 9,
Even if the molten steel 3 flowing into the rising side immersion pipe 9 is blown from the blowing lance, a blowing pipe is provided below the surface of the molten steel 3 in the lower tank 8. You may blow it in. In short, the present invention can be applied to any position where the gas is blown, as long as it is blown together with the carrier gas. In addition, the number of the desulfurizing agent blowing pipes 12 is not limited to one, and the present invention can be applied to a plurality of the desulfurizing agent blowing pipes.
【００２０】[0020]
【実施例】図１に示すＲＨ真空脱ガス装置を用いて転炉
から出鋼された１ヒート２５０トンの溶鋼に本発明を適
用した例を以下に説明する。ＲＨ真空脱ガス装置の溶鋼
環流量は１５０ｔ／ｍｉｎであり、使用した脱硫剤は、
ＣａＦ2 濃度が１５mass％のＣａＯ−ＣａＦ2 系粉状脱
硫剤で、脱硫剤の添加量を６．０ｋｇ／ｔの一定値とし
た。そして、脱硫剤の吹き込み速度を２０〜１００ｋｇ
／ｍｉｎとし、又、キャリアガスとしてＡｒを２０００
〜３０００Ｎｌ／ｍｉｎの流量で吹き込み、合計１４ヒ
ート脱硫処理した（実施例１〜１４）。その際、脱硫処
理の前後に溶鋼から分析用試料を採取して溶鋼中硫黄濃
度を分析し、脱硫率を調査した。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to molten steel of 250 tons per heat, which is produced from a converter by using an RH vacuum degassing apparatus shown in FIG. 1, will be described below. The molten steel ring flow rate of the RH vacuum degassing device was 150 t / min, and the desulfurizing agent used was:
CaF 2 concentration is 15 mass% of CaO-CaF 2 based powdery desulfurizing agent, and the amount of desulfurizing agent to a constant value of 6.0 kg / t. And, the blowing speed of the desulfurizing agent is 20 to 100 kg.
/ Min and Ar as a carrier gas of 2000
Blowing was performed at a flow rate of Ｎ3000 Nl / min to perform a total of 14 heat desulfurization treatments (Examples 1 to 14). At that time, samples for analysis were taken from the molten steel before and after the desulfurization treatment, the sulfur concentration in the molten steel was analyzed, and the desulfurization rate was investigated.
【００２１】又、比較のために、脱硫剤の吹き込み速度
を１００ｋｇ／ｍｉｎ越えとし、その他の条件を上記実
施例と同一とした操業（比較例１〜５）と、キャリアガ
ス流量を２０００Ｎｌ／ｍｉｎ未満とし、その他の条件
を上記実施例と同一とした操業（比較例６〜１２）を実
施した。表１に、実施例及び比較例での操業条件及び操
業結果をまとめて示す。For comparison, the operation (comparative examples 1 to 5) in which the blowing rate of the desulfurizing agent was set to 100 kg / min and the other conditions were the same as in the above example, and the carrier gas flow rate was 2000 Nl / min The operation (Comparative Examples 6 to 12) was performed with the other conditions being the same as those of the above examples. Table 1 summarizes the operating conditions and operating results in the examples and comparative examples.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１に示すように、実施例１〜１４までの
全ての実施例において、７０％以上の高い脱硫率が得ら
れ、脱硫後の溶鋼中硫黄濃度は１０ｐｐｍ以下であっ
た。それに対して、比較例１〜１２までの全ての比較例
で、脱硫率は低く、脱硫後の溶鋼中硫黄濃度が１０ｐｐ
ｍ以下となった操業は、比較例８と比較例１１の２ヒー
トのみであった。As shown in Table 1, in all of Examples 1 to 14, a high desulfurization rate of 70% or more was obtained, and the sulfur concentration in the molten steel after desulfurization was 10 ppm or less. In contrast, in all of Comparative Examples 1 to 12, the desulfurization rate was low, and the sulfur concentration in the molten steel after desulfurization was 10 pp.
m was less than m for only two heats of Comparative Example 8 and Comparative Example 11.
【００２４】図２は、キャリアガス流量が２０００Ｎｌ
／ｍｉｎ以上である実施例１〜１４及び比較例１〜５の
試験結果から、脱硫率と脱硫剤吹き込み速度との関係を
調査した結果を示す図である。図２に示すように、脱硫
剤吹き込み速度が１００ｋｇ／ｍｉｎ以下であれば、脱
硫率は高位安定しているが、脱硫剤吹き込み速度が１０
０ｋｇ／ｍｉｎを越えた範囲では、脱硫剤吹き込み速度
の上昇と共に脱硫率が低下することが分かった。FIG. 2 shows that the carrier gas flow rate is 2000 Nl.
It is a figure which shows the result of having investigated the relationship between the desulfurization rate and the desulfurizing agent blowing speed from the test results of Examples 1 to 14 and Comparative Examples 1 to 5 which are not less than / min. As shown in FIG. 2, when the desulfurizing agent injection speed is 100 kg / min or less, the desulfurization rate is high and stable, but the desulfurizing agent injection speed is 10 kg / min.
It was found that in the range exceeding 0 kg / min, the desulfurization rate decreased as the desulfurizing agent blowing rate increased.
【００２５】図３は、脱硫剤吹き込み速度が１００ｋｇ
／ｍｉｎ以下である実施例１〜１４及び比較例６〜１２
の試験結果から、脱硫率とキャリアガス流量との関係を
調査した結果を示す図である。図３に示すように、キャ
リアガス流量が２０００Ｎｌ／ｍｉｎ以上であれば、脱
硫率は高位安定しているが、キャリアガス流量が２００
０Ｎｌ／ｍｉｎ未満の範囲では、キャリアガス流量の減
少と共に脱硫率が低下することが分かった。FIG. 3 shows that the blowing rate of the desulfurizing agent is 100 kg.
/ Min and Examples 1-14 and Comparative Examples 6-12
FIG. 4 is a diagram showing the results of an investigation of the relationship between the desulfurization rate and the flow rate of carrier gas from the test results of FIG. As shown in FIG. 3, when the carrier gas flow rate is 2000 Nl / min or more, the desulfurization rate is high and stable, but the carrier gas flow rate is 200
It was found that in the range of less than 0 Nl / min, the desulfurization rate decreased as the flow rate of the carrier gas decreased.
【００２６】このように本発明の実施例では、安定した
高い脱硫率で脱硫することができ、硫黄濃度を１０ｐｐ
ｍ以下に下げることができた。又、キャリアガス中に混
入して排出される脱硫剤が減少したので、少ない脱硫剤
使用量で目的とする水準まで脱硫することができた。As described above, in the embodiment of the present invention, desulfurization can be performed at a stable and high desulfurization rate, and the sulfur concentration can be reduced to 10 pp.
m or less. Further, since the desulfurizing agent mixed into the carrier gas and discharged was reduced, it was possible to desulfurize to a target level with a small amount of the desulfurizing agent used.
【００２７】[0027]
【発明の効果】本発明では、キャリアガス中に混入して
排出される脱硫剤を減少させて脱硫反応に関与する脱硫
剤を実質的に多くすることができるので、高脱硫率で安
定して脱硫することが可能となる。その結果、少ない脱
硫剤使用量で所定値まで脱硫することが可能となる。According to the present invention, since the desulfurizing agent involved in the desulfurization reaction can be substantially increased by reducing the amount of the desulfurizing agent mixed into the carrier gas and discharged, the desulfurizing agent can be stably obtained at a high desulfurization rate. Desulfurization becomes possible. As a result, it is possible to desulfurize to a predetermined value with a small amount of desulfurizing agent used.
【図１】本発明を実施したＲＨ真空脱ガス装置の縦断面
概略図である。FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus embodying the present invention.
【図２】脱硫率と脱硫剤吹き込み速度との関係を調査し
た結果を示す図である。FIG. 2 is a view showing a result of an investigation on a relationship between a desulfurization rate and a desulfurizing agent blowing speed.
【図３】脱硫率とキャリアガス流量との関係を調査した
結果を示す図である。FIG. 3 is a diagram showing a result of investigation on a relationship between a desulfurization rate and a carrier gas flow rate.
１ ＲＨ真空脱ガス装置 ２ 取鍋 ３ 溶鋼 ４ スラグ ５ 脱硫剤 ６ 真空槽 ７ 上部槽 ８ 下部槽 ９ 上昇側浸漬管 １０ 下降側浸漬管 １１ Ａｒ吹き込み管 １２ 脱硫剤吹き込み管 １３ ホッパー １４ 原料投入口 １５ ダクト DESCRIPTION OF SYMBOLS 1 RH vacuum degassing apparatus 2 Ladle 3 Molten steel 4 Slag 5 Desulfurizer 6 Vacuum tank 7 Upper tank 8 Lower tank 9 Upside immersion pipe 10 Downside immersion pipe 11 Ar blowing pipe 12 Desulfurizing agent blowing pipe 13 Hopper 14 Raw material inlet 15 Duct
フロントページの続き (72)発明者 狛谷 昌紀 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 赤井 真一 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 松野 英寿 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 (72)発明者 村井 剛 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 Ｆターム(参考） 4K013 AA00 AA09 BA05 BA08 CA02 CA11 CA15 CB04 CB09 CC01 CE01 CE05 CE07 CF13 EA03 EA09 EA19 Continuing on the front page (72) Inventor Masaki Komatani 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Shinichi Akai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Inside (72) Inventor Hidetoshi Matsuno 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Go Murai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. F term (reference) 4K013 AA00 AA09 BA05 BA08 CA02 CA11 CA15 CB04 CB09 CC01 CE01 CE05 CE07 CF13 EA03 EA09 EA19
Claims (1)
中に吹き込み、吹き込んだ脱硫剤と溶鋼とをＲＨ真空脱
ガス装置の真空槽内で混合して脱硫する溶鋼の脱硫方法
において、前記脱硫剤の吹き込み速度を１００ｋｇ／ｍ
ｉｎ以下とし、且つ、前記キャリアガスの流量を２００
０Ｎｌ／ｍｉｎ以上とすることを特徴とするＲＨ真空脱
ガス装置での溶鋼の脱硫方法。1. A method for desulfurizing molten steel, comprising blowing a desulfurizing agent in powder form into molten steel together with a carrier gas and mixing the blown desulfurizing agent and molten steel in a vacuum chamber of an RH vacuum degassing apparatus to desulfurize the molten steel. 100 kg / m
in or less, and the flow rate of the carrier gas is 200
A method for desulfurizing molten steel in an RH vacuum degassing apparatus, wherein the desulfurization is performed at 0 Nl / min or more.
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|---|---|---|---|
| JP2000355477A JP2002161310A (en) | 2000-11-22 | 2000-11-22 | Desulfurization process for liquid steel using rh vacuum degassing equipment |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000355477A JP2002161310A (en) | 2000-11-22 | 2000-11-22 | Desulfurization process for liquid steel using rh vacuum degassing equipment |
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| Publication Number | Publication Date |
|---|---|
| JP2002161310A true JP2002161310A (en) | 2002-06-04 |
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ID=18827888
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103966402A (en) * | 2014-05-14 | 2014-08-06 | 东北大学 | RH (Relative Humidity) vacuum refining system and desulfuration method for molten steel desulfuration |
-
2000
- 2000-11-22 JP JP2000355477A patent/JP2002161310A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103966402A (en) * | 2014-05-14 | 2014-08-06 | 东北大学 | RH (Relative Humidity) vacuum refining system and desulfuration method for molten steel desulfuration |
| CN103966402B (en) * | 2014-05-14 | 2016-07-13 | 东北大学 | RH vacuum refining system and sulfur method for molten steel desulfurizing |
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