JP6521177B2 - Method and apparatus for desulfurizing molten iron - Google Patents

Method and apparatus for desulfurizing molten iron Download PDF

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JP6521177B2
JP6521177B2 JP2018514569A JP2018514569A JP6521177B2 JP 6521177 B2 JP6521177 B2 JP 6521177B2 JP 2018514569 A JP2018514569 A JP 2018514569A JP 2018514569 A JP2018514569 A JP 2018514569A JP 6521177 B2 JP6521177 B2 JP 6521177B2
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desulfurizing agent
molten iron
desulfurization
desulfurizing
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JPWO2017188159A1 (en
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俊夫 井蓋
俊夫 井蓋
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Nippon Steel 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
    • 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
    • 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

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 method and an apparatus for desulfurizing molten iron.

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 [S] ≦ 24 ppm, in order to reduce the desulfurization load in secondary refining, desulfurizer and deoxidizer are simultaneously introduced at the time of tapping steel from the converter to the ladle Desulfurization was performed by throwing the shoot into the ladle. However, the desulfurization rate was low because the desulfurizing agent was less likely 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 of performing desulfurization by adding a deoxidizer, a desulfurizing agent, and a slag modifier to molten steel in a steel discharge. In this method, the desulfurizing agent and the molten steel are reacted by stirring using the stirring energy of the steel discharge flow at the time of converter discharge.

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 a molten steel discharged 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。   The invention disclosed by patent document 1 reacts a desulfurization agent and molten steel only with the stirring energy which an output steel stream has. For this reason, since the stirring power is insufficient and the desulfurizing agent can not 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, it is effective to reduce the particle size of the desulfurizing agent in order to improve the desulfurization rate. However, when the fine-grained desulfurizing agent (about 1 mm) is used in the invention disclosed by Patent Document 1, part of the desulfurizing agent unavoidably scatters and dissipates. Thereby, the fall of the yield of a desulfurization agent and the defect of desulfurization generate | occur | produce.

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。   To practice the invention disclosed by Patent Document 2, as described in paragraph 0033 and FIG. 1 of Patent Document 2, the lance 2 is brought close to the injection flow 18, the inclination angle of the lance 2 is changed, and 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 feeding device 16. For this reason, equipment costs rise. In addition, since the lance 2 needs to be disposed in the vicinity of the converter 12 separately from the raw material feeding device 16, the equipment is enlarged.

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。   An object of the present invention is to provide a technology capable of desulfurizing molten iron at a high desulfurization rate at the time of hot water discharge from a smelting furnace (for example, a converter) to a smelting vessel (for example, a 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 method for desulfurizing molten iron, which comprises adding a desulfurizing agent to a hot water stream flowing down while fluctuating the flow position when pouring molten iron from the smelting furnace to the smelting vessel,
A spray nozzle attached to a feed chute having a variable feed direction to feed the raw material into the interior of the refining vessel and releasing the desulfurizing agent, a storage vessel for storing the desulfurization agent, and the desulfurizing agent stored in the storage vessel Using a spraying equipment having a desulfurizing agent supply path for supplying to the spraying nozzle,
The desulfurizing agent is a method for desulfurizing molten iron in which the desulfurizing agent is sprayed from the spraying nozzle to the outlet flow while making the spraying direction of the desulfurizing agent by the spraying nozzle follow the fluctuation of the flow-down position of the outlet flow with the input 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, which adds a desulfurizing agent to a tapping stream flowing down while fluctuating the flowing position when pouring molten iron from the smelting furnace to the smelting vessel,
A spray nozzle attached to a feed chute having a variable feed direction to feed the raw material into the interior of the refining vessel and releasing the desulfurizing agent, a storage vessel for storing the desulfurization agent, and the desulfurizing agent stored in the storage vessel Equipped with a spray facility having a desulfurizing agent supply path for supplying to the spray nozzle;
The spray direction of the desulfurization agent by the spray nozzle is variable along with the input chute, and the spray nozzle is a desulfurization device for molten iron that can spray the desulfurization agent following the fluctuation of the flow position of the outlet flow. .

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 inventions, it is preferable that the position where the desulfurizing agent is sprayed to the tapping stream is above the 1/2 height position between the tapping point of the smelting furnace and the surface of the molten iron 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 inventions, the particle diameter 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 inventions, the desulfurization agent may be sprayed from the spray nozzle onto the outlet stream during a period of 3/4 or more of the period from the start of the outlet of molten iron from the smelting furnace to the outlet of the molten iron to the end of the outlet. 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 inventions, starting the introduction of the deoxidizer from the input chute into the interior of the refining vessel at the same time as or before the start of the desulfurization agent spraying from the spraying 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 the present invention, it is exemplified that the molten iron is a molten steel. In this case, the smelting furnace is exemplified as a smelting furnace performing primary smelting in steel making performing secondary smelting, specifically a converter, and the smelting vessel is a ladle, for example. Be 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 flowing 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 hot water flow and the stirring power of the hot water flowing stream. For this reason, the desulfurization rate can be increased.

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。   Also, as in the conventional case, when a desulfurizing agent is added to the surface of the molten metal in the smelting vessel from the input chute, etc., the desulfurizing agent that can not be fully digested is dusted, causing a loss of the desulfurizing agent and problems with the working environment. . For this reason, the fine-grained desulfurizing agent could not be used. However, according to the present invention, the desulfurization agent has a high rate of aging, and even fine-grained desulfurization agents can be sprayed without loss, so 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 simply by attaching a spray nozzle for releasing the desulfurizing agent to the existing input chute. Therefore, according to the present invention, since it is not necessary to provide the lance moving device disclosed in Patent Document 2, it is possible to prevent an increase in facility cost and an increase in facility size.

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 the 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 in the case of using the desulfurizing agents CaO-CaF 2 and CaO-Al 2 O 3 for the inventive 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 a molten steel, the smelting furnace is a converter which is a smelting furnace for performing primary smelting in steel making that performs secondary smelting, and the smelting vessel is a ladle will be exemplified. In the following description, “%” relating to a chemical composition or concentration means “% by mass” unless otherwise noted.

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 the configuration of the 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 desulfurizing apparatus 0 is an apparatus for adding a desulfurizing agent 7 to the molten steel 11 at the time of tapping after primary refining in steelmaking that performs secondary refining. The desulfurization apparatus 0 is provided with a spraying facility 6. The spraying equipment 6 sprays the desulfurizing agent 7 onto the steel outlet flow 11 which is discharged from the converter 1 which has performed the primary refining to the ladle 2 which performs the secondary refining and flows down. The type and type of converter 1 used in primary refining are not 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 equipment 6 has a spray nozzle 3, a storage container 4, and a desulfurizing agent supply path 5. The spray nozzle 3 is attached to the input chute 8. The feeding chute 8 is provided so that the feeding direction can be varied in three dimensions in order to load an alloy (for example, a deoxidizer) into the inside of the ladle 2. The input chute 8 may be an existing one.

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 discharges the desulfurizing agent 11 and blows the desulfurizing agent 7 onto the outgoing steel stream 11 flowing down while changing the flow down position. The storage container 4 stores the desulfurizing agent 7. The desulfurizing agent supply path 7 is, for example, a pipe, and supplies the desulfurizing 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 input chute 8 so that the direction of the injection port of the desulfurizing agent 7 is variably disposed. Thereby, the spray nozzle 3 can spray the desulfurizing agent 7 in accordance with the fluctuation of the flow-down position of the outlet steel flow 11. That is, the spray nozzle 3 is disposed such that the injection 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 steel outlet 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 to prevent scattering of the desulfurizing agent.

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 of about [S] ≦ 24 ppm. According to the present invention, as shown in FIG. 1, the desulfurization agent 7 is sprayed from the spray nozzle 3 to the steel outlet flow 11 using the spray equipment 6 when steel is discharged from the converter 1 to the ladle 2.

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 to the steel outlet flow 11, the energy of the spraying and the agitation energy of the steel outlet flow 11 can be effectively utilized. Therefore, the entrapment of the desulfurizing agent 7 in the steel strip 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 surface of molten steel from a charging chute or the like, as described above, a fine-grained desulfurizing agent could not be used. On the other hand, according to the present invention, since the entrainment of the desulfurizing agent 7 in the output steel stream 11 is increased, for example, the fine particle desulfurizing agent 7 having a particle diameter of 0.5 to 1.0 mm can be used. As the desulfurization agent 7 has a finer particle size, the surface area contributing to the desulfurization reaction increases, so the desulfurization rate can be further increased. If the particle size of the desulfurizing agent 7 is smaller than 0.5 mm, the desulfurizing agent that can not be fully formed becomes dusty, while if the particle size of the desulfurizing agent 7 is larger than 1.0 mm, the desulfurization rate decreases. Thus, according to the present invention, it becomes possible to spray the fine-grained desulfurizing agent 7, and the desulfurization rate is improved.

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, and 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 be made to follow the outgoing steel flow 11 flowing down while changing the downstream position, and the desulfurization agent 7 be continued to be blown to 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, due to the tilt angle of the converter 1, the partial clogging of the steel outlet 13 and the like, the steel extraction flow 11 flows downward while changing the flow-down position in the horizontal plane. For this reason, the blowing direction of the desulfurizing agent 7 is easily deviated from the output steel flow 11, and the desulfurization rate is easily reduced. In the present invention, loss of the desulfurizing agent 7 can be prevented because the blowing direction of the blowing nozzle 3 follows the outgoing steel flow 11.

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 which sprays the desulfurizing agent 7 to the steel discharge flow 11 is higher than the height position of 1/2 between the distance from the steel outlet 13 to the surface 12 of the molten steel in the ladle 2 Is preferred. Thereby, the desulfurizing agent 7 can be introduced into the hot water surface 12 together with the steel outlet flow 11 from a higher position, and the potential energy can also be utilized to increase the stirring power.

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 to spray 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。   Spraying of the desulfurizing agent 7 from the spraying nozzle 3 to the steel outlet flow 11 is 3/4 or more of the period from the start of tapping of molten steel from the converter 1 to the ladle 2 to the end of steel tapping. It is preferable to increase the desulfurization rate by performing for a period, most preferably the entire 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）At the same time as or before the start of spraying of the desulfurizing agent from the spraying nozzle 3, it is preferable to start the feeding of the deoxidizer from the feeding chute 8 to the inside of the ladle 2. 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, reversion occurs due to the reverse reaction and the desulfurization rate decreases. The desulfurization rate can be further increased by lowering the concentration of oxygen in the molten steel and the concentration of oxides in the slag by also feeding the deoxidizer from the feeding 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 onto the outlet steel stream 11, and various methods such as putting in the ladle 2 and addition to the outlet steel stream 11 can be used. Moreover, a generally used deoxidizer can be used, and it is not particularly limited. For example, a deoxidizer containing Al is preferred. The addition amount of the deoxidizer may be appropriately determined depending on the amount of oxygen in molten steel required, and is not 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 only by attaching the spray nozzle 3 for releasing the desulfurizing agent 7 to the existing input chute 8. Therefore, according to the present invention, since it is not necessary to provide the lance moving device disclosed in Patent Document 2, it is possible to prevent an increase in facility cost and an increase in facility size.

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 determined using the desulfurization apparatus 0 according to the present invention shown in FIG. 1 and the conventional desulfurization apparatus in which the spray equipment 6 was removed from the desulfurization apparatus 0. That is, at the time of tapping of the molten steel 7 in which blowing (primary refining) was performed by the converter 1 by conventional means, a desulfurizing agent was added, and the desulfurization rate was determined from [S] before and after tapping.

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 tapping hole 13 of the converter 1 is 250 mm. The desulfurizing agent 7 was added by spraying the steel outlet 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 of 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 of the desulfurization agent 7 is located at the upper center of the input chute 8 so that the spray direction of the desulfurization agent 7 in the horizontal surface matches the input direction from the input chute 8 in the horizontal surface. It is fixed and arranged by appropriate means such as welding and 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。   Therefore, the direction in which the desulfurization agent 7 is sprayed from the spray nozzle 3 is directed to the steel outlet flow 11 as the feed chute 8 is operated and the feed direction is changed to the direction toward the ladle 2. Be changed. Thereby, the desulfurization agent 7 is made to follow the fluctuation of the flow-down position of the steel discharge flow 11 for the entire period from the start of tapping of the molten steel 11 from the converter 1 to the ladle 2 to the end of steel tapping. , Kept blowing.

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 spraying position of the desulfurizing agent 7 to the steel outlet flow 11 was above the half height between the steel outlet 13 and the surface 12 of the molten metal.

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, the desulfurizing agent was injected from the input 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 example of the present invention and the conventional example.

Figure 0006521177
Figure 0006521177

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 molten steel (after steel tapping).

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 inventive example and the conventional example. The particle size of the desulfurizing agent was -5 mm in the conventional example and 0.5-1.0 mm in the inventive example. The amount of desulfurizing agent input 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 understand the S concentration before and after desulfurization, sampling was performed before and after tapping steel to confirm the sulfur concentration [S] in molten steel. Thereafter, the desulfurization rate (%) before and after tapping was determined based on each sulfur concentration. Assuming that [S] 0 is a sulfur concentration before steel removal and [S] 1 is a sulfur concentration after steel removal, the desulfurization ratio is calculated as [S] 0- [S] 1 ) / [S] 0 × 100 (%) Be

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 in the case of using the desulfurizing agents CaO-CaF 2 and CaO-Al 2 O 3 for the inventive 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, the desulfurization rate of the example of the present invention is about 1.2 times that of the comparative example in any case using the desulfurizing agents CaO-CaF 2 and CaO-Al 2 O 3. 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。   The desulfurizing agent 7 having a particle diameter of 0.5 to 1 mm was introduced into the ladle 2 from the introduction chute 8. However, it was visually confirmed that the desulfurizing agent 7 which could not be fully turned into dust, could not confirm the suspension on the molten steel in the ladle 2, and did not mix.

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 equipment 1 according to the present invention Smelting furnace (converter, etc.)
2 Refining container (ladle)
3 Spray nozzle 4 container (hopper)
5 Piping 6 Spraying equipment 7 Desulfurization agent 8 Input chute 11 Outgoing steel flow 12 Hot water surface 13 Outgoing steel port

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, which comprises adding a desulfurizing agent to a hot water stream flowing down while fluctuating the flow position when pouring molten iron from the smelting furnace to the smelting vessel,
A spray nozzle attached to a feed chute having a variable feed direction for feeding a raw material into the interior of the refining vessel and discharging a desulfurizing agent, a storage vessel storing the desulfurizing agent, and the desulfurization stored in the storage vessel Using a spray facility having a desulfurizing agent supply path for supplying the spray agent to the spray nozzle;
In the molten iron, the desulfurizing agent is sprayed from the spraying nozzle to the outlet flow while making the spraying direction of the desulfurizing agent by the spraying nozzle follow the fluctuation of the flow-down position of the outlet flow with the injection chute. 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 to the tapping stream is above the half height position between the tapping point of the refining furnace and the surface of the molten iron in the refining vessel. Desulfurization method of described molten iron. 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 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。   The desulfurizing agent is sprayed from the spray nozzle onto the discharge stream during a period of 3⁄4 or more of a period from the start of the discharge of the molten iron from the smelting furnace to the smelting vessel to the end of the discharge; The method for desulfurizing molten iron according to any one of claims 1 to 3. 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。   At the same time as or before the start of spraying the desulfurizing agent from the spraying nozzle, the feeding of the deoxidizer from the feeding chute into the interior of the refining vessel 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 any one of claims 1 to 5, 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 said desulfurization furnace is a desulfurization furnace which performs primary refinement in steelmaking which performs secondary refinement, The desulfurization method of the hot metal of Claim 6 characterized by the above-mentioned. 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 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 desulfurization apparatus for molten iron, which adds a desulfurizing agent to a hot water stream flowing down while fluctuating the flow down position when pouring molten iron from the smelting furnace to the smelting vessel,
A spray nozzle attached to a feed chute having a variable feed direction for feeding a raw material into the interior of the refining vessel and discharging a desulfurizing agent, a storage vessel storing the desulfurizing agent, and the desulfurization stored in the storage vessel And spray equipment having a desulfurizing agent supply path for supplying the agent to the spray nozzle,
The spraying direction of the desulfurizing agent by the spraying nozzle is variable along with the feeding chute, and the spraying nozzle can spray the desulfurizing agent in accordance with the fluctuation of the outflow position of the tapping flow. Desulfurizer for molten iron.

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