JPWO2017188159A1 - Method and apparatus for desulfurizing molten iron - Google Patents

Method and apparatus for desulfurizing molten iron Download PDF

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JPWO2017188159A1
JPWO2017188159A1 JP2018514569A JP2018514569A JPWO2017188159A1 JP WO2017188159 A1 JPWO2017188159 A1 JP WO2017188159A1 JP 2018514569 A JP2018514569 A JP 2018514569A JP 2018514569 A JP2018514569 A JP 2018514569A JP WO2017188159 A1 JPWO2017188159 A1 JP WO2017188159A1
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desulfurizing agent
molten iron
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JP6521177B2 (en
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俊夫 井蓋
俊夫 井蓋
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising

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  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
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Abstract

転炉出鋼時に高い脱硫率で脱硫を行う技術を提供する。投入シュート８に設けられた吹付けノズル３と脱硫剤を貯蔵する容器（ホッパー）４とそれらを接続する配管５からなる吹付け設備６を用いて、精錬容器１から取鍋２に出鋼する際に吹付けノズル３から出鋼流１１に脱硫剤７を吹付ける。
Provides technology to perform desulfurization at a high desulfurization rate when steel is output from converters. Steel is discharged from the refining vessel 1 to the ladle 2 using a blowing facility 6 comprising a spray nozzle 3 provided on the input chute 8, a container (hopper) 4 for storing a desulfurizing agent, and a pipe 5 connecting them. At that time, the desulfurizing agent 7 is sprayed from the spray nozzle 3 to the outgoing steel flow 11.

Description

本発明は、溶鉄の脱硫方法及び脱硫装置に関する。   The present invention relates to a molten iron desulfurization method and a desulfurization apparatus.

従来、例えば［Ｓ］≦２４ｐｐｍの低硫鋼を溶製する際には、二次精錬における脱硫負荷を軽減するため、転炉から取鍋への出鋼時に脱硫剤及び脱酸剤を同時に投入シュートから取鍋へ投入することにより脱硫を行っていた。しかし、脱硫剤が溶鋼へ巻き込まれ難いため、脱硫率が低かった。   Conventionally, for example, when melting low sulfur steel with [S] ≦ 24ppm, desulfurizing agent and deoxidizing agent are added simultaneously when steel is discharged from the converter to the ladle to reduce the desulfurization load in secondary refining. Desulfurization was performed by putting it into the ladle from the chute. However, the desulfurization rate was low because the desulfurization agent was difficult to be caught in the molten steel.

特許文献１には、脱酸剤、脱硫剤及びスラグ改質剤を出鋼中の溶鋼に添加することにより脱硫を行う方法が開示されている。この方法は、脱硫剤と溶鋼を、転炉出鋼時の出鋼流が有する攪拌エネルギーを利用して攪拌して反応させる。   Patent Document 1 discloses a method for performing desulfurization by adding a deoxidizer, a desulfurizer, and a slag modifier to molten steel in steel. In this method, a desulfurizing agent and molten steel are stirred and reacted using the stirring energy of the steel output at the time of converter steel output.

特許文献２には、転炉から取鍋に出鋼される溶鋼に向けて、加熱した粉状のフラックスを、ランスを介して吹き付けることにより、溶鋼を精錬する方法が開示されている。   Patent Document 2 discloses a method of refining molten steel by spraying a heated powdery flux through a lance toward the molten steel delivered from a converter to a ladle.

特開平８−２２５８２４号公報JP-A-8-225824 特開２００５−１８７９０１号公報JP 2005-187901 A

特許文献１により開示された発明は、出鋼流が有する攪拌エネルギーだけで脱硫剤と溶鋼を反応させる。このため、攪拌力が不足して脱硫剤を有効に利用できないため、脱硫率が低い。   In the invention disclosed in Patent Document 1, the desulfurization agent and molten steel are reacted with only the stirring energy of the outgoing steel stream. For this reason, since the stirring power is insufficient and the desulfurizing agent cannot be used effectively, the desulfurization rate is low.

また、脱硫剤の粒径を細かくすることが脱硫率を向上するためには有効である。しかし、特許文献１により開示された発明において細粒の脱硫剤（〜１ｍｍ程度）を用いると、脱硫剤の一部が不可避的に飛散して散逸する。これにより、脱硫剤の歩留まりの低下や脱硫の不良が発生する。   Further, reducing the particle size of the desulfurizing agent is effective for improving the desulfurization rate. However, when a fine-grain desulfurization agent (about 1 mm) is used in the invention disclosed in Patent Document 1, a part of the desulfurization agent inevitably scatters and dissipates. As a result, the yield of the desulfurizing agent is reduced and the desulfurization defect occurs.

特許文献２により開示された発明を実施するには、特許文献２の段落００３３及び図１に記載されるように、ランス２を注入流１８に近付け、ランス２の傾斜角度を変更し、さらに、ランス２を上下方向へ移動及び傾斜させるために、ランス移動装置（図示せず）を、原料投入装置１６とは別に新たに設ける必要がある。このため、設備コストが上昇する。また、ランス２を、原料投入装置１６とは別に転炉１２の近傍に配置する必要もあるため、設備が大型化する。   In order to implement the invention disclosed in Patent Document 2, as described in Paragraph 0033 of FIG. 1 and FIG. 1, the lance 2 is moved closer to the injection flow 18, the inclination angle of the lance 2 is changed, In order to move and tilt the lance 2 in the vertical direction, it is necessary to newly provide a lance moving device (not shown) separately from the raw material charging device 16. For this reason, equipment cost rises. Moreover, since it is necessary to arrange | position the lance 2 in the vicinity of the converter 12 separately from the raw material injection | throwing-in apparatus 16, an installation enlarges.

本発明の目的は、精錬炉（例えば転炉）から精錬容器（例えば取鍋）への出湯時に高い脱硫率で溶鉄の脱硫を行うことができる技術を提供することである。   The objective of this invention is providing the technique which can desulfurize molten iron with a high desulfurization rate at the time of the tapping from a refining furnace (for example, converter) to a refining container (for example, ladle).

本発明は、精錬炉から精錬容器へ溶鉄を出湯する際に、流下位置を変動しながら流下する出湯流に脱硫剤を添加する溶鉄の脱硫方法であって、
精錬容器の内部に原料を投入するために投入方向が可変の投入シュートに取り付けられ、脱硫剤を放出する吹付けノズルと、脱硫剤を貯蔵する貯蔵容器と、貯蔵容器に貯蔵された脱硫剤を吹付けノズルへ供給する脱硫剤供給路とを有する吹付け設備を用い、
吹付けノズルによる脱硫剤の吹付け方向を、投入シュートとともに、出湯流の流下位置の変動に追随させながら、吹付けノズルから出湯流へ脱硫剤を吹付ける、溶鉄の脱硫方法である。The present invention is a molten iron desulfurization method of adding a desulfurizing agent to a tapping stream flowing down while changing the flow position when discharging molten iron from a smelting furnace to a smelting vessel,
A spray nozzle that discharges a desulfurizing agent, a storage container that stores the desulfurizing agent, and a desulfurizing agent that is stored in the storage container are attached to a charging chute having a variable charging direction in order to charge the raw material into the refining vessel. Using a spraying facility having a desulfurization agent supply path for supplying to the spray nozzle,
This is a molten iron desulfurization method in which the desulfurization agent is sprayed from the spray nozzle to the tapping stream while the direction of spraying the desulfurizing agent by the spraying nozzle follows the change in the downstream position of the tapping stream along with the charging chute.

別の観点からは、本発明は、精錬炉から精錬容器へ溶鉄を出湯する際に、流下位置を変動しながら流下する出湯流に脱硫剤を添加する溶鉄の脱硫装置であって、
精錬容器の内部に原料を投入するために投入方向が可変の投入シュートに取り付けられ、脱硫剤を放出する吹付けノズルと、脱硫剤を貯蔵する貯蔵容器と、貯蔵容器に貯蔵された脱硫剤を吹付けノズルへ供給する脱硫剤供給路とを有する吹付け設備を備え、
吹付けノズルによる脱硫剤の吹付け方向は、投入シュートとともに可変であり、吹付けノズルは、脱硫剤を出湯流の流下位置の変動に追随して吹付けることができる、溶鉄の脱硫装置である。From another point of view, the present invention is a desulfurization apparatus for molten iron that adds a desulfurization agent to a tapping stream that flows down while varying the flow position when tapping molten iron from a smelting furnace to a smelting vessel,
A spray nozzle that discharges a desulfurizing agent, a storage container that stores the desulfurizing agent, and a desulfurizing agent that is stored in the storage container are attached to a charging chute having a variable charging direction in order to charge the raw material into the refining vessel. A spraying facility having a desulfurization agent supply path for supplying to the spray nozzle;
The direction in which the desulfurizing agent is sprayed by the spray nozzle is variable along with the charging chute, and the spray nozzle is a molten iron desulfurization device that can spray the desulfurizing agent in accordance with the change in the downstream position of the tapping stream. .

これらの本発明では、出湯流に脱硫剤を吹付ける位置は、精錬炉の出湯口から精錬容器内の溶鉄の湯面までの間の１／２の高さ位置より上側であることが、好ましい。   In these present inventions, the position where the desulfurization agent is sprayed on the tapping stream is preferably above the half height position between the tapping port of the smelting furnace and the molten iron surface in the smelting vessel. .

これらの本発明では、脱硫剤の粒径は０．５〜１．０ｍｍであることが好ましい。   In these present inventions, the particle size of the desulfurizing agent is preferably 0.5 to 1.0 mm.

これらの本発明では、精錬炉から精錬容器への溶鉄の出湯の開始時から出湯の終了時までの期間の３／４以上の期間に、吹付けノズルから出湯流に脱硫剤を吹付けることが好ましい。   In these present inventions, the desulfurization agent can be sprayed from the spray nozzle to the tapping stream during a period of 3/4 or more of the period from the start of pouring of the molten iron from the smelting furnace to the smelting vessel to the end of the tapping. preferable.

これらの本発明では、吹付けノズルから脱硫剤の吹付けを開始する時と同時に、または該開始する時よりも先に、投入シュートから精錬容器の内部への脱酸剤の投入を開始することが好ましい。   In these present inventions, the introduction of the deoxidizer from the charging chute to the inside of the refining vessel is started simultaneously with or before the start of the spraying of the desulfurizing agent from the spray nozzle. Is preferred.

これらの本発明では、前記溶鉄は溶鋼であることが例示される。この場合、前記精錬炉は、二次精錬を行う製鋼における一次精錬を行う精錬炉であること、具体的には転炉であることが例示され、前記精錬容器は取鍋であることが、例示される。   In these inventions, the molten iron is exemplified as molten steel. In this case, the smelting furnace is exemplified as a smelting furnace that performs primary smelting in steelmaking that performs secondary smelting, specifically a converter, and an example that the smelting vessel is a ladle. Is done.

本発明によれば、脱硫剤を流下する出湯流に吹き付けるため、脱硫剤の出湯流に対する吹付けと出湯流の撹拌力を利用して溶鉄への脱硫剤の巻き込みを増加できる。このため、脱硫率を高めることができる。   According to the present invention, since the desulfurizing agent is sprayed onto the outgoing hot water stream, it is possible to increase the entrainment of the desulfurizing agent into the molten iron by utilizing the blowing of the desulfurizing agent to the outgoing hot water stream and the stirring force of the outgoing hot water stream. For this reason, a desulfurization rate can be raised.

また、従来のように、投入シュートなどから精錬容器内の溶湯の湯面へ脱硫剤を添加すると、滓化し切れない脱硫剤が粉塵化し、脱硫剤のロスや作業環境上の問題などが発生する。このため、細粒の脱硫剤を使用できなかった。しかし、本発明によれば、脱硫剤の滓化速度が高く、細粒の脱硫剤であってもロス無く吹付けることができるため、脱硫率をより高めることができる。   In addition, if a desulfurizing agent is added to the molten metal surface in the refining vessel from a charging chute, etc. as before, the desulfurizing agent that cannot be fully hatched becomes dust, resulting in loss of the desulfurizing agent and problems in the working environment. . For this reason, a fine-grain desulfurization agent could not be used. However, according to the present invention, the hatching rate of the desulfurizing agent is high, and even a fine-grained desulfurizing agent can be sprayed without loss, so that the desulfurization rate can be further increased.

さらに、本発明は、脱硫剤を放出する吹付けノズルを既存の投入シュートに装着するだけで、実施できる。したがって、本発明によれば、特許文献２により開示されたランス移動装置を設ける必要が無いため、設備コストの上昇や設備の大型化を防止できる。   Furthermore, the present invention can be implemented only by mounting a spray nozzle for releasing a desulfurizing agent on an existing charging chute. Therefore, according to the present invention, since it is not necessary to provide the lance moving device disclosed in Patent Document 2, an increase in equipment cost and an increase in equipment size can be prevented.

図１は、本発明に係る溶鋼の脱硫装置の構成を示す説明図である。FIG. 1 is an explanatory view showing a configuration of a molten steel desulfurization apparatus according to the present invention. 図２は、本発明例及び従来例について、脱硫剤ＣａＯ−ＣａＦ２，ＣａＯ−Ａｌ２Ｏ３を用いた場合の脱硫率を示すグラフである。FIG. 2 is a graph showing the desulfurization rate when the desulfurization agents CaO—CaF 2 and CaO—Al 2 O 3 are used for the present invention example and the conventional example.

以降の説明では、溶鉄が溶鋼であり、精錬炉が二次精錬を行う製鋼において一次精錬を行う精錬炉である転炉であるとともに、精錬容器が取鍋である場合を例にとる。また、以降の説明では、特に断りがない限り、化学組成または濃度に関する「％」は「質量％」を意味する。   In the following description, the case where the molten iron is molten steel, the smelting furnace is a converter that is a refining furnace that performs primary refining in steelmaking that performs secondary refining, and the refining vessel is a ladle is taken as an example. In the following description, “%” related to chemical composition or concentration means “mass%” unless otherwise specified.

１．本発明に係る脱硫装置０
図１は、本発明に係る溶鋼の脱硫装置０の構成を示す説明図である。1. Desulfurization apparatus 0 according to the present invention
FIG. 1 is an explanatory view showing a configuration of a molten steel desulfurization apparatus 0 according to the present invention.

図１に示すように、脱硫装置０は、二次精錬を行う製鋼において、一次精錬後の出鋼時に脱硫剤７を溶鋼１１に添加するための装置である。脱硫装置０は、吹付け設備６を備える。吹付け設備６は、一次精錬を行った転炉１から二次精錬を行う取鍋２へ出鋼されて流下する出鋼流１１に、脱硫剤７を吹き付ける。なお、一次精錬で用いる転炉１の型式や種類は制限されない。   As shown in FIG. 1, the desulfurization apparatus 0 is an apparatus for adding a desulfurizing agent 7 to the molten steel 11 during steelmaking after primary refining in steelmaking for secondary refining. The desulfurization apparatus 0 includes a spraying facility 6. The spraying equipment 6 sprays the desulfurizing agent 7 on the steel output stream 11 that is discharged from the converter 1 that has undergone primary refining to the ladle 2 that performs secondary refining. In addition, the model and kind of the converter 1 used by primary refining are not restrict | limited.

吹付け設備６は、吹付けノズル３と、貯蔵容器４と、脱硫剤供給路５を有する。吹付けノズル３は、投入シュート８に取り付けられる。投入シュート８は、取鍋２の内部に合金（例えば脱酸剤）を投入するために、投入方向が三次元で可変になるように、設けられる。投入シュート８は既存のものを用いればよい。   The spray facility 6 includes a spray nozzle 3, a storage container 4, and a desulfurization agent supply path 5. The spray nozzle 3 is attached to the charging chute 8. The charging chute 8 is provided so that the charging direction is variable in three dimensions in order to load an alloy (for example, a deoxidizer) into the ladle 2. The existing chute 8 may be used.

吹付けノズル３は、脱硫剤１１を放出し、流下位置を変動しながら流下する出鋼流１１に脱硫剤７を吹付ける。貯蔵容器４は脱硫剤７を貯蔵する。脱硫剤供給路７は、例えば配管であり、貯蔵容器４に貯蔵された脱硫剤１１を吹付けノズル３へ供給する。   The spray nozzle 3 releases the desulfurizing agent 11 and sprays the desulfurizing agent 7 to the outgoing steel flow 11 flowing down while changing the flow down position. The storage container 4 stores the desulfurizing agent 7. The desulfurization agent supply path 7 is a pipe, for example, and supplies the desulfurization agent 11 stored in the storage container 4 to the spray nozzle 3.

吹付けノズル３は、投入シュート８に取り付けられることにより、脱硫剤７の噴射口の向きが可変に配置される。これにより、吹付けノズル３は、出鋼流１１の流下位置の変動に追随して脱硫剤７を吹き付けることができる。すなわち、吹付けノズル３は、脱硫剤７の噴射方向（吹付け方向）が出鋼流１１の流下位置の変動範囲を被う範囲で可変となるように、配置される。   The spray nozzle 3 is attached to the charging chute 8 so that the direction of the injection port of the desulfurizing agent 7 is variably arranged. Thereby, the spray nozzle 3 can spray the desulfurizing agent 7 following the change in the flow-down position of the outgoing steel flow 11. That is, the spray nozzle 3 is arranged so that the spraying direction (spraying direction) of the desulfurizing agent 7 is variable in a range that covers the fluctuation range of the flow-down position of the outgoing steel flow 11.

吹付けノズルの型式や種類は特に制限されない。ノズル径は、脱硫剤の飛散防止のため、好ましくは２００〜３００ｍｍである。   The type and type of the spray nozzle are not particularly limited. The nozzle diameter is preferably 200 to 300 mm in order to prevent the desulfurization agent from scattering.

２．本発明に係る脱硫方法
本発明は、［Ｓ］≦２４ｐｐｍ程度の低硫鋼を対象とする。本発明は、図１に示すように、転炉１から取鍋２に出鋼する際に吹付け設備６を用い、吹付けノズル３から出鋼流１１に脱硫剤７を吹付ける。2. The desulfurization method according to the present invention The present invention is directed to a low-sulfur steel with [S] ≦ 24 ppm. In the present invention, as shown in FIG. 1, when the steel is discharged from the converter 1 to the ladle 2, the blowing equipment 6 is used, and the desulfurizing agent 7 is sprayed from the spray nozzle 3 to the steel outlet flow 11.

吹付けノズル３から出鋼流１１に脱硫剤７を吹付けることによって、吹付けのエネルギー及び出鋼流１１の撹拌エネルギーを有効に活用できる。このため、出鋼流１１への脱硫剤７の巻き込みを増加でき、脱硫率が向上する。   By spraying the desulfurizing agent 7 from the spray nozzle 3 onto the outgoing steel stream 11, the energy of the spraying and the stirring energy of the outgoing steel stream 11 can be effectively utilized. For this reason, the entrainment of the desulfurizing agent 7 into the outgoing steel flow 11 can be increased, and the desulfurization rate is improved.

従来、投入シュートなどからの溶鋼の湯面への脱硫剤の添加では、上述したように、細粒の脱硫剤を使用できなかった。これに対し、本発明によれば、出鋼流１１への脱硫剤７の巻き込みが増加するため、例えば粒径が０．５〜１．０ｍｍの細粒の脱硫剤７を用いることができる。脱硫剤７は、粒度が細かい程、脱硫反応に寄与する表面積が増加するため、脱硫率をより高めることができる。脱硫剤７の粒径が０．５ｍｍより小さいと滓化し切れない脱硫剤が粉塵化し、一方、脱硫剤７の粒径が１．０ｍｍより大きくなると、脱硫率が低下する。このように、本発明によれば、細粒の脱硫剤７を吹付けることが可能になり、脱硫率が向上する。   Conventionally, in the addition of a desulfurizing agent to the molten steel surface from a charging chute or the like, a fine desulfurizing agent cannot be used as described above. On the other hand, according to this invention, since the entrainment of the desulfurizing agent 7 into the outgoing steel flow 11 increases, for example, the fine desulfurizing agent 7 having a particle diameter of 0.5 to 1.0 mm can be used. As the particle size of the desulfurizing agent 7 is finer, the surface area contributing to the desulfurization reaction increases, and therefore the desulfurization rate can be further increased. When the particle size of the desulfurizing agent 7 is smaller than 0.5 mm, the desulfurizing agent that cannot be completely hatched is dusted. On the other hand, when the particle size of the desulfurizing agent 7 is larger than 1.0 mm, the desulfurization rate decreases. Thus, according to this invention, it becomes possible to spray the fine-grain desulfurization agent 7, and a desulfurization rate improves.

脱硫剤７の組成は、一般的に脱硫剤として用いられる組成であればよく、特に制限されない。好ましくは、ＣａＯ単体あるいは、ＣａＯにＣａＦ２やＡｌ２Ｏ３を一部添加した組成ＣａＯ−ＣａＦ２，ＣａＯ−Ａｌ２Ｏ３が例示される。脱硫剤の添加量は制限されない。The composition of the desulfurizing agent 7 is not particularly limited as long as it is a composition generally used as a desulfurizing agent. Preferable examples include CaO alone or compositions CaO—CaF 2 and CaO—Al 2 O 3 in which CaF 2 and Al 2 O 3 are partially added to CaO. The amount of desulfurizing agent added is not limited.

この際に、吹付けノズル３の吹付け方向を、流下位置を変動しながら流下する出鋼流１１に追随させ、出鋼流１１に脱硫剤７を吹付け続けることが好ましい。転炉１の出鋼口１３の径は一般的に１５０〜２５０ｍｍであり、出銑口の径は１１００〜１３００ｍｍである。このため、溶銑流に比べて出鋼流１１は細い。さらに、出鋼流１１は、転炉１の傾転角度や出鋼口１３の部分的な詰まり等に起因して、水平面内での流下位置を変動しながら、流下する。このため、脱硫剤７の吹付け方向が出鋼流１１からずれ易く、脱硫率が低下し易い。本発明では、吹付けノズル３の吹付け方向を出鋼流１１に追随させるため、脱硫剤７のロスを防止できる。   At this time, it is preferable that the blowing direction of the blowing nozzle 3 is made to follow the outgoing steel flow 11 flowing down while the flow down position is changed, and the desulfurizing agent 7 is continuously sprayed onto the outgoing steel flow 11. The diameter of the steel outlet 13 of the converter 1 is generally 150 to 250 mm, and the diameter of the steel outlet is 1100 to 1300 mm. For this reason, the outgoing steel flow 11 is thinner than the hot metal flow. Furthermore, the outgoing steel flow 11 flows down while changing the flow down position in the horizontal plane due to the tilt angle of the converter 1 or partial clogging of the outgoing steel port 13. For this reason, the spraying direction of the desulfurizing agent 7 is likely to deviate from the outgoing steel flow 11, and the desulfurization rate is likely to decrease. In this invention, since the blowing direction of the blowing nozzle 3 follows the outgoing steel flow 11, the loss of the desulfurizing agent 7 can be prevented.

また、出鋼流１１に脱硫剤７を吹付ける吹付け位置は、出鋼口１３から取鍋２内の溶鋼の湯面１２までの距離の間の１／２の高さ位置よりも上側であることが好ましい。これにより、より高い位置から出鋼流１１とともに脱硫剤７を湯面１２に投入することができ、位置エネルギーも利用して攪拌力を高めることができるからである。   Moreover, the spraying position at which the desulfurizing agent 7 is sprayed onto the outgoing steel flow 11 is above the half height position between the outgoing steel outlet 13 and the molten steel surface 12 in the ladle 2. Preferably there is. This is because the desulfurizing agent 7 can be introduced into the molten metal surface 12 together with the outgoing steel flow 11 from a higher position, and the stirring power can be increased using the potential energy.

脱硫剤７の吹付けには不活性ガスを用いることができる。不活性ガスとしては、好ましくはＡｒガスあるいはＮ２ガスである。脱硫剤７の噴射圧は好ましくは０．５〜１．０ＭＰａである。An inert gas can be used for spraying the desulfurizing agent 7. The inert gas is preferably Ar gas or N 2 gas. The injection pressure of the desulfurizing agent 7 is preferably 0.5 to 1.0 MPa.

吹付けノズル３から出鋼流１１への脱硫剤７の吹付けは、転炉１から取鍋２への溶鋼の出鋼の開始時から出鋼の終了時までの期間の３／４以上の期間、最も好ましくは全期間に行うことが、脱硫率を高めるために好ましい。   The spraying of the desulfurizing agent 7 from the spray nozzle 3 to the outgoing steel flow 11 is not less than 3/4 of the period from the start of the molten steel output from the converter 1 to the ladle 2 until the end of the outgoing steel. In order to increase the desulfurization rate, it is preferable to carry out for a period, most preferably for the whole period.

また、吹付けノズル３から脱硫剤の吹付けを開始する時と同時に、またはこの時よりも先に、投入シュート８から取鍋２の内部への脱酸剤の投入を開始することが好ましい。脱硫反応が下記の式（１）に示す還元反応である。このため、溶鋼中の酸素の濃度やスラグ中のＦｅＯ，ＭｎＯといった酸化物の濃度が高いと逆反応により復硫して脱硫率が低下する。投入シュート８より脱酸剤も投入することにより溶鋼中の酸素の濃度やスラグ中の酸化物の濃度を低下することにより、脱硫率をさらに高めることができる。
ＣａＯ＋［Ｓ］＝ＣａＳ＋［Ｏ］ ・・・・・（１）In addition, it is preferable to start the introduction of the deoxidizer from the charging chute 8 into the ladle 2 at the same time or before the start of the spraying of the desulfurizing agent from the spray nozzle 3. The desulfurization reaction is a reduction reaction represented by the following formula (1). For this reason, if the concentration of oxygen in the molten steel and the concentration of oxides such as FeO and MnO in the slag are high, the desulfurization rate is reduced due to the reverse reaction. The desulfurization rate can be further increased by lowering the concentration of oxygen in the molten steel and the concentration of oxide in the slag by introducing a deoxidizer from the input chute 8.
CaO + [S] = CaS + [O] (1)

脱酸剤は、出鋼流１１に吹付ける必要はなく、取鍋２への入れ置きや出鋼流１１への添加など、様々な方法を用いることができる。また、脱酸剤は、一般的に用いられるものを用いることができ、特に制限されない。例えば、Ａｌを含有する脱酸剤が好ましい。脱酸剤の添加量は、必要とされる溶鋼中酸素量に応じて適宜決定すればよく、制限されない。   The deoxidizer does not need to be sprayed on the outgoing steel flow 11, and various methods such as placing in the ladle 2 and adding to the outgoing steel flow 11 can be used. Moreover, what is generally used can be used for a deoxidizer, and it does not restrict | limit in particular. For example, a deoxidizer containing Al is preferable. What is necessary is just to determine suitably the addition amount of a deoxidizer according to the amount of oxygen in molten steel required, and is not restrict | limited.

さらに、本発明は、脱硫剤７を放出する吹付けノズル３を、既設の投入シュート８に装着するだけで、実施できる。したがって、本発明によれば、特許文献２により開示されたランス移動装置を設ける必要が無いため、設備コストの上昇や設備の大型化を防止できる。   Furthermore, the present invention can be implemented simply by mounting the spray nozzle 3 for releasing the desulfurizing agent 7 on the existing charging chute 8. Therefore, according to the present invention, since it is not necessary to provide the lance moving device disclosed in Patent Document 2, an increase in equipment cost and an increase in equipment size can be prevented.

図１に示す本発明に係る脱硫装置０と、脱硫装置０から吹付け設備６を除いた従来例の脱硫装置を用い、脱硫率を求めた。すなわち、慣用手段によって転炉１による吹錬（一次精錬）が行われた溶鋼７の出鋼時に、脱硫剤を添加し、出鋼前後の［Ｓ］から脱硫率を求めた。   The desulfurization rate was calculated | required using the desulfurization apparatus 0 which concerns on this invention shown in FIG. 1, and the desulfurization apparatus of the prior art example which excluded the spraying equipment 6 from the desulfurization apparatus 0. FIG. In other words, a desulfurizing agent was added when the molten steel 7 was blown (primary refining) by the converter 1 by conventional means, and the desulfurization rate was obtained from [S] before and after the steel output.

転炉１の出鋼孔１３の大きさは２５０ｍｍである。脱硫剤７を、吹付け装置０を用いて出鋼流１１に吹き付けることにより、添加した。吹付けノズル３のノズル径は２００ｍｍである。脱硫剤７のキャリアガスとしてＡｒガスを用いた。   The size of the steel outlet hole 13 of the converter 1 is 250 mm. The desulfurizing agent 7 was added by spraying the outgoing steel stream 11 using the spraying device 0. The nozzle diameter of the spray nozzle 3 is 200 mm. Ar gas was used as a carrier gas for the desulfurizing agent 7.

脱硫装置０では、脱硫剤７の吹付けノズル３は、水平面内における脱硫剤７の吹付け方向が水平面内における投入シュート８からの投入方向と一致するように、投入シュート８の上部中央に、溶接や締結といった適宜手段により固定されて、配置される。   In the desulfurization apparatus 0, the spray nozzle 3 for the desulfurizing agent 7 is disposed at the upper center of the charging chute 8 so that the blowing direction of the desulfurizing agent 7 in the horizontal plane coincides with the charging direction from the charging chute 8 in the horizontal plane. It is fixed and arranged by appropriate means such as welding or fastening.

したがって、吹付けノズル３からの脱硫剤７の吹付け方向は、投入シュート８が操作されて投入方向が取鍋２へ向かう方向に変更されることに伴って、出鋼流１１へ向かう方向に変更される。これにより、脱硫剤７を、転炉１から取鍋２への溶鋼１１の出鋼の開始時から出鋼の終了時までの全期間について、出鋼流１１の流下位置の変動に追随させながら、吹付け続けた。   Accordingly, the blowing direction of the desulfurizing agent 7 from the blowing nozzle 3 is changed to the direction toward the outgoing steel flow 11 as the charging chute 8 is operated to change the charging direction toward the ladle 2. Be changed. Thereby, the desulfurizing agent 7 is made to follow the fluctuation of the flow-down position of the output steel flow 11 for the entire period from the start of the steel discharge of the molten steel 11 from the converter 1 to the ladle 2 until the end of the steel output. Continued to spray.

出鋼流１１への脱硫剤７の吹付け位置は、出鋼口１３から湯面１２までの間の１／２の高さ位置より上側とした。   The position where the desulfurizing agent 7 was sprayed onto the outgoing steel flow 11 was set above the half height position between the outgoing steel outlet 13 and the molten metal surface 12.

一方、従来例として、投入シュート８から取鍋２の内部の溶鋼へ脱硫剤を投入した。   On the other hand, as a conventional example, a desulfurizing agent was charged from the charging chute 8 to the molten steel inside the ladle 2.

表１に本発明例及び従来例それぞれの条件を示す。   Table 1 shows the conditions of the present invention example and the conventional example.

Figure 2017188159
Figure 2017188159

合金成分としてＭｎ，Ｓｉ合金を投入し、脱酸剤としてＡｌを３ｋｇ／ｔ投入した。表１に、溶鋼（出鋼後）の化学組成と溶鋼温度を示す。   Mn and Si alloys were added as alloy components, and 3 kg / t of Al was added as a deoxidizer. Table 1 shows the chemical composition and molten steel temperature of the molten steel (after steelmaking).

脱硫剤には、本発明例及び従来例ともに、ＣａＯ−ＣａＦ２，ＣａＯ−Ａｌ２Ｏ３の二種類を用いた。脱硫剤の粒径は、従来例では−５ｍｍであり、本発明例では０．５〜１．０ｍｍであった。脱硫剤の投入量はいずれも５ｋｇ／ｔであった。As the desulfurizing agent, two types of CaO—CaF 2 and CaO—Al 2 O 3 were used in both the present invention example and the conventional example. The particle size of the desulfurizing agent was −5 mm in the conventional example, and 0.5 to 1.0 mm in the example of the present invention. The input amount of the desulfurizing agent was 5 kg / t.

脱硫の前後のＳ濃度を把握するため、出鋼の前後にサンプリングを行い、溶鋼中硫黄濃度［Ｓ］を確認した。その後、各硫黄濃度に基づいて出鋼前後の脱硫率（％）を求めた。［Ｓ］０を出鋼前硫黄濃度、［Ｓ］１を出鋼後硫黄濃度とすると、脱硫率は、［Ｓ］０−［Ｓ］１）／［Ｓ］０×１００（％）として求められる。In order to grasp the S concentration before and after the desulfurization, sampling was performed before and after the steelmaking to check the sulfur concentration [S] in the molten steel. Thereafter, the desulfurization rate (%) before and after the steel output was determined based on each sulfur concentration. When [S] 0 is the sulfur concentration before steel output and [S] 1 is the sulfur concentration after steel output, the desulfurization rate is obtained as [S] 0 − [S] 1 ) / [S] 0 × 100 (%). It is done.

図２は、本発明例及び従来例について、脱硫剤ＣａＯ−ＣａＦ２，ＣａＯ−Ａｌ２Ｏ３を用いた場合の脱硫率を示すグラフである。図２のグラフにおける黒い柱が本発明例であり、白い柱が従来例である。FIG. 2 is a graph showing the desulfurization rate when the desulfurization agents CaO—CaF 2 and CaO—Al 2 O 3 are used for the present invention example and the conventional example. The black column in the graph of FIG. 2 is an example of the present invention, and the white column is a conventional example.

図２のグラフに示すように、脱硫剤ＣａＯ−ＣａＦ２，ＣａＯ−Ａｌ２Ｏ３を用いたいずれの場合においても、本発明例の脱硫率は比較例の脱硫率の約１．２倍である。As shown in the graph of FIG. 2, in any case using the desulfurization agents CaO—CaF 2 and CaO—Al 2 O 3 , the desulfurization rate of the inventive example is about 1.2 times the desulfurization rate of the comparative example. is there.

なお、粒径が０．５〜１ｍｍの脱硫剤７を投入シュート８から取鍋２に投入した。しかし、滓化し切れない脱硫剤７が粉塵化し、取鍋２内の溶鋼への懸濁を確認できず、混ざらなかったことが目視で確認された。   A desulfurizing agent 7 having a particle size of 0.5 to 1 mm was introduced into the ladle 2 from the introduction chute 8. However, it was confirmed visually that the desulfurizing agent 7 which could not be hatched was dusted, and the suspension in the molten steel in the ladle 2 could not be confirmed and was not mixed.

０ 本発明に係る脱硫装置
１ 精錬炉（転炉等）
２ 精錬容器（取鍋）
３ 吹付けノズル
４ 容器（ホッパー）
５ 配管
６ 吹付け設備
７ 脱硫剤
８ 投入シュート
１１ 出鋼流
１２ 湯面
１３ 出鋼口

0 Desulfurization apparatus 1 according to the present invention Refining furnace (converter, etc.)
2 Refining container (ladder)
3 Spray nozzle 4 Container (hopper)
5 Piping 6 Spraying equipment 7 Desulfurization agent 8 Input chute 11 Steel flow 12 Hot water surface 13 Steel outlet

Claims (9)

精錬炉から精錬容器へ溶鉄を出湯する際に、流下位置を変動しながら流下する出湯流に脱硫剤を添加する溶鉄の脱硫方法であって、
前記精錬容器の内部に原料を投入するために投入方向が可変の投入シュートに取り付けられ、脱硫剤を放出する吹付けノズルと、脱硫剤を貯蔵する貯蔵容器と、該貯蔵容器に貯蔵された脱硫剤を前記吹付けノズルへ供給する脱硫剤供給路とを有する吹付け設備を用い、
前記吹付けノズルによる前記脱硫剤の吹付け方向を、前記投入シュートとともに、前記出湯流の流下位置の変動に追随させながら、前記吹付けノズルから前記出湯流へ前記脱硫剤を吹付ける、溶鉄の脱硫方法。A method for desulfurizing molten iron in which a desulfurizing agent is added to a tapping stream that flows down while changing the flow position when molten iron is tapped from a smelting furnace to a smelting vessel,
A blowing nozzle attached to a charging chute having a variable charging direction for charging the raw material into the smelting vessel, discharges the desulfurizing agent, a storage vessel for storing the desulfurizing agent, and desulfurization stored in the storage vessel Using a spraying facility having a desulfurizing agent supply path for supplying the agent to the spray nozzle,
The molten iron spraying the desulfurizing agent from the spray nozzle to the tapping stream while following the change in the flow down position of the tapping stream with the charging chute along the blowing direction of the desulfurizing agent by the spray nozzle. Desulfurization method. 前記出湯流に前記脱硫剤を吹付ける位置は、前記精錬炉の出湯口から前記精錬容器内の溶鉄の湯面までの間の１／２の高さ位置よりも上側である、請求項１に記載の溶鉄の脱硫方法。   The position where the desulfurizing agent is sprayed onto the tapping stream is above the half height position between the tapping port of the smelting furnace and the molten iron surface in the smelting vessel. The molten iron desulfurization method as described. 前記脱硫剤の粒径は０．５〜１．０ｍｍである、請求項１または２に記載の溶鉄の脱硫方法。   The method for desulfurizing molten iron according to claim 1 or 2, wherein the particle size of the desulfurizing agent is 0.5 to 1.0 mm. 前記精錬炉から前記精錬容器への前記溶鉄の出湯の開始時から該出湯の終了時までの期間の３／４以上の期間に、前記吹付けノズルから前記出湯流に前記脱硫剤を吹付ける、請求項１〜３のいずれかに記載の溶鉄の脱硫方法。   Spraying the desulfurization agent from the spray nozzle to the tapping stream during a period of 3/4 or more of the period from the start of tapping the molten iron to the smelting vessel from the refining furnace to the end of the tapping; The method for desulfurizing molten iron according to claim 1. 前記吹付けノズルから前記脱硫剤の吹付けを開始する時と同時に、または該開始する時よりも先に、前記投入シュートから前記精錬容器の内部への脱酸剤の投入を開始する、請求項１〜４のいずれかに記載の溶鉄の製造方法。   The injection of the deoxidizer from the charging chute to the inside of the refining vessel is started at the same time as or when the spraying of the desulfurizing agent from the spray nozzle is started. The manufacturing method of the molten iron in any one of 1-4. 前記溶鉄は溶鋼である、請求項１〜５のいずれかに記載の溶鉄の脱硫方法。   The method for desulfurizing molten iron according to claim 1, wherein the molten iron is molten steel. 前記精錬炉は、二次精錬を行う製鋼における一次精錬を行う精錬炉である、請求項６に記載の溶銑の脱硫方法。   The hot metal desulfurization method according to claim 6, wherein the refining furnace is a refining furnace that performs primary refining in steelmaking that performs secondary refining. 前記精錬炉は転炉であるとともに前記精錬容器は取鍋である、請求項７に記載の溶鉄の脱硫方法。   The method for desulfurizing molten iron according to claim 7, wherein the smelting furnace is a converter and the smelting vessel is a ladle. 精錬炉から精錬容器へ溶鉄を出湯する際に、流下位置を変動しながら流下する出湯流に脱硫剤を添加する溶鉄の脱硫装置であって、
前記精錬容器の内部に原料を投入するために投入方向が可変の投入シュートに取り付けられ、脱硫剤を放出する吹付けノズルと、脱硫剤を貯蔵する貯蔵容器と、該貯蔵容器に貯蔵された脱硫剤を前記吹付けノズルへ供給する脱硫剤供給路とを有する吹付け設備を備え、
前記吹付けノズルによる前記脱硫剤の吹付け方向は、前記投入シュートとともに可変であり、前記吹付けノズルは、前記脱硫剤を前記出湯流の流下位置の変動に追随して吹付けることができる、溶鉄の脱硫装置。

A molten iron desulfurization device that adds a desulfurizing agent to a tapping stream that flows down while changing the flow position when the molten iron is tapped from a smelting furnace to a smelting vessel,
A blowing nozzle attached to a charging chute having a variable charging direction for charging the raw material into the smelting vessel, discharges the desulfurizing agent, a storage vessel for storing the desulfurizing agent, and desulfurization stored in the storage vessel Spraying equipment having a desulfurization agent supply path for supplying the agent to the spray nozzle,
The blowing direction of the desulfurizing agent by the blowing nozzle is variable together with the charging chute, and the blowing nozzle can spray the desulfurizing agent following the change in the downstream position of the tapping stream, Molten iron desulfurization equipment.

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