JPH1151574A - Operation method for arc furnace - Google Patents
Operation method for arc furnaceInfo
- Publication number
- JPH1151574A JPH1151574A JP20755997A JP20755997A JPH1151574A JP H1151574 A JPH1151574 A JP H1151574A JP 20755997 A JP20755997 A JP 20755997A JP 20755997 A JP20755997 A JP 20755997A JP H1151574 A JPH1151574 A JP H1151574A
- Authority
- JP
- Japan
- Prior art keywords
- chamber
- iron source
- melting chamber
- melting
- preheating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Furnace Details (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、溶解室と溶解室に
直結するシャフト型予熱室とを有するアーク炉で、鉄ス
クラップや直接還元鉄等の鉄源を溶解して溶鋼を製造す
る操業方法において、効率良く鉄源を溶解する方法に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc furnace having a melting chamber and a shaft-type preheating chamber directly connected to the melting chamber, and an operation method for manufacturing molten steel by melting an iron source such as iron scrap or directly reduced iron. And a method for efficiently dissolving the iron source.
【０００２】[0002]
【従来の技術】近年、鉄スクラップの発生量の増大と共
に、世界的に製鋼用アーク炉が新設されている。このア
ーク炉では、電極から発生するアーク熱により、鉄スク
ラップや直接還元鉄等の鉄源を加熱・溶解し、精錬して
溶鋼を製造するが、多くの電力を消費するため、溶解中
にアーク炉溶解室から発生する高温の排ガスにより鉄源
を予熱して加熱・溶解し、電力使用量を極力少なくする
方法が多数提案されている。2. Description of the Related Art In recent years, with the increase in the amount of generated iron scrap, an arc furnace for steelmaking has been newly installed worldwide. In this arc furnace, the arc heat generated from the electrodes heats and melts iron sources such as iron scrap and direct reduced iron, and refines the molten steel to produce molten steel. There have been proposed many methods for preheating and heating and melting an iron source with a high-temperature exhaust gas generated from a furnace melting chamber, thereby minimizing power consumption.
【０００３】例えば、特開平７−１８０９７５号公報
（以下、「先行技術１」と記す）には、１段又は２段以
上の開閉可能な火格子を装着したシャフト型予熱炉を、
アーク炉溶解室の上方に、鉄スクラップ導入路を介して
接続して設け、アーク炉溶解室の排ガスにより、シャフ
ト型予熱炉内で予熱された鉄スクラップを、シャフト型
予熱炉下部に設けたプッシャーにより、アーク炉予熱室
内に連続的又は間歇的に装入する方法が開示されてい
る。For example, Japanese Unexamined Patent Publication No. 7-180975 (hereinafter referred to as “prior art 1”) discloses a shaft-type preheating furnace equipped with a grate that can be opened and closed in one or more stages.
A pusher is provided above the arc furnace melting chamber, connected via an iron scrap introduction path, and the iron scrap preheated in the shaft type preheating furnace by the exhaust gas from the arc furnace melting chamber is provided at the lower part of the shaft type preheating furnace. Discloses a method of continuously or intermittently charging an arc furnace preheating chamber.
【０００４】特開平７−３３２８７４号公報（以下、
「先行技術２」と記す）には、アーク炉溶解室の上蓋に
接続する水平方向に配置したロータリードラム型の第１
の予熱室と、第１の予熱室と底部で接続するシャフト型
の第２の予熱室とを配置し、第２の予熱室内で溶解室か
ら発生する排ガスにて鉄源を予熱した後、プッシャーに
て第１の予熱室に鉄源を押し込み、そして、回転する第
１の予熱室を介して、溶解室内に予熱された鉄源を装入
する方法が開示されている。[0004] Japanese Patent Application Laid-Open No. 7-332874 (hereinafter referred to as
The “prior art 2”) includes a rotary drum type first drum connected to an upper lid of an arc furnace melting chamber.
And a shaft type second preheating chamber connected to the first preheating chamber at the bottom with the first preheating chamber, and after preheating the iron source with exhaust gas generated from the melting chamber in the second preheating chamber, Discloses a method of pushing an iron source into a first preheating chamber, and charging the preheated iron source into the melting chamber via the rotating first preheating chamber.
【０００５】又、特公平６−４６１４５号公報（以下、
「先行技術３」と記す）には、溶解室に直結するシャフ
ト型予熱室を設け、溶解室内とシャフト型予熱室内とに
１ヒート分の鉄源を溶解毎に装入し、排ガスでシャフト
型予熱室内の鉄源を予熱しつつ、溶解された鉄源に見合
う量を溶解室内に自由落下させ、こうして、溶解室内と
シャフト型予熱室内とに装入された全ての鉄源を溶解す
る設備が開示されている。In addition, Japanese Patent Publication No. 6-46145 (hereinafter referred to as "Japanese Patent Publication")
In “Prior art 3”, a shaft-type preheating chamber directly connected to the melting chamber is provided, and an iron source for one heat is charged into the melting chamber and the shaft-type preheating chamber for each melting, and the exhaust gas is used to form a shaft type preheating chamber. While preheating the iron source in the preheating chamber, an amount corresponding to the melted iron source is freely dropped into the melting chamber, and thus a facility for melting all the iron sources charged in the melting chamber and the shaft type preheating chamber is provided. It has been disclosed.
【０００６】[0006]
【発明が解決しようとする課題】以上のような方法によ
り、予熱効果の高いものでは、２５０〜２７０ｋＷｈ／
ｔの電力原単位が達成されるとしているが、上記先行技
術１〜３には以下の問題点がある。According to the above method, if the preheating effect is high, 250 to 270 kWh /
Although it is stated that the power consumption unit of t is achieved, the above prior arts 1 to 3 have the following problems.
【０００７】先行技術１及び先行技術２では、予熱され
た鉄源をアーク炉溶解室内に装入するために、プッシャ
ー又はロータリードラムといった鉄源搬送用の装置が必
要であり、このため、溶解室からの排ガスで予熱する際
に、予熱温度に限界がある。即ち、溶解室に大量のコー
クス等の補助熱源と酸素ガスとを吹き込み、この排ガス
で鉄源を予熱すれば、予熱温度が高くなり予熱効果が向
上するが、上記の搬送用装置の熱変形や融着等の設備ト
ラブルが発生するので、排ガス温度を上げることができ
ない。In the prior art 1 and the prior art 2, an apparatus for transporting the iron source such as a pusher or a rotary drum is required to load the preheated iron source into the arc furnace melting chamber. There is a limit to the preheating temperature when preheating with exhaust gas from That is, if a large amount of auxiliary heat source such as coke and oxygen gas are blown into the melting chamber and the iron source is preheated with this exhaust gas, the preheating temperature is increased and the preheating effect is improved. Since an equipment trouble such as fusion occurs, the exhaust gas temperature cannot be increased.
【０００８】これに対して、先行技術３では、シャフト
型予熱室が溶解室に直結されているため、上述した鉄源
搬送用装置を必要とせず、従って、上記の問題点も発生
しない。しかしながら、先行技術３では、１ヒート分の
溶鋼量を溶解する毎に、予熱室内の鉄源を全て溶解し、
予熱室内に鉄源が残らない状態で溶鋼を出鋼するため、
次ヒートの最初に装入される鉄源の予熱ができないため
に、排ガスの有効利用という点では十分とはいえない。On the other hand, in the prior art 3, since the shaft-type preheating chamber is directly connected to the melting chamber, the above-described iron source transfer device is not required, and therefore, the above-described problem does not occur. However, in Prior Art 3, every time the amount of molten steel for one heat is melted, all the iron sources in the preheating chamber are melted,
To discharge molten steel without leaving an iron source in the preheating chamber,
Since the iron source inserted at the beginning of the next heat cannot be preheated, it cannot be said that the exhaust gas is used effectively.
【０００９】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、予熱室から溶解室への鉄源搬
送用装置を必要とせず、又、次ヒートの初期に装入され
る鉄源の予熱も可能であり、そして、従来の排ガスを利
用した予熱方法では達成できなかった高効率で鉄源を溶
解することのできるアーク炉操業方法を提供することで
ある。The present invention has been made in view of the above circumstances,
The purpose is to eliminate the need for a device for transporting the iron source from the preheating chamber to the melting chamber, to preheat the iron source charged at the beginning of the next heat, and to reduce the conventional exhaust gas. An object of the present invention is to provide an arc furnace operation method capable of melting an iron source with high efficiency, which cannot be achieved by the preheating method used.
【００１０】[0010]
【課題を解決するための手段】第１の発明によるアーク
炉操業方法は、溶解室と、溶解室に直結したシャフト型
の予熱室とを有し、溶解室で発生する排ガスを予熱室に
導入して鉄スクラップ等の鉄源を予熱して溶解するアー
ク炉の操業方法において、鉄源が溶解室と予熱室とに連
続して存在する状態を保つように予熱室への鉄源の供給
を継続しながら溶解室内の鉄源を溶解し、溶解室に複数
ヒート分の溶鋼量が確保された時点で予熱室への鉄源の
供給を停止し、次いで、溶解室及び予熱室内の未溶解の
鉄源を全て溶解した後、１ヒート分の溶鋼量ずつ分割し
て出鋼することを特徴とするものである。An arc furnace operating method according to a first aspect of the present invention has a melting chamber and a shaft-type preheating chamber directly connected to the melting chamber, and introduces exhaust gas generated in the melting chamber into the preheating chamber. In the operation method of an arc furnace for preheating and melting an iron source such as an iron scrap, the supply of the iron source to the preheating chamber is performed so that the iron source continuously exists in the melting chamber and the preheating chamber. While continuing to melt the iron source in the melting chamber, supply of the iron source to the preheating chamber was stopped when the amount of molten steel for multiple heats was secured in the melting chamber, and then the unmelted iron in the melting chamber and the preheating chamber was melted. It is characterized in that after all of the iron source is melted, tapping is performed by dividing the amount of molten steel for one heat.
【００１１】第２の発明によるアーク炉操業方法は、第
１の発明において、溶解室と予熱室とに連続して存在す
る鉄源の量が、１ヒートの溶鋼量の５０ｗｔ％以上であ
ることを特徴とするものである。[0011] In the arc furnace operating method according to the second invention, in the first invention, the amount of the iron source continuously present in the melting chamber and the preheating chamber is 50 wt% or more of the molten steel amount in one heat. It is characterized by the following.
【００１２】第３の発明によるアーク炉操業方法は、第
１又は第２の発明において、コークス等の補助熱源と酸
素ガスとを溶解室内に供給することを特徴とするもので
ある。An arc furnace operating method according to a third invention is characterized in that, in the first or second invention, an auxiliary heat source such as coke and oxygen gas are supplied into a melting chamber.
【００１３】第４の発明によるアーク炉操業方法は、第
３の発明において、酸素ガスの供給量が２５Ｎｍ3 ／ｔ
以上であることを特徴とするものである。According to a fourth aspect of the present invention, in the arc furnace operating method according to the third aspect, the supply amount of oxygen gas is 25 Nm 3 / t.
The above is the feature.
【００１４】第５の発明によるアーク炉操業方法は、第
１の発明ないし第４の発明の何れかの発明において、出
鋼前溶解室内に４ヒート分以上の溶鋼量を確保すること
を特徴とするものである。An arc furnace operating method according to a fifth invention is characterized in that, in any one of the first invention to the fourth invention, a molten steel amount of 4 heats or more is secured in the melting chamber before tapping. Is what you do.
【００１５】第６の発明によるアーク炉操業方法は、第
１の発明ないし第５の発明の何れかの発明において、分
割して出鋼する際に、少なくとも１回は２０分間以上の
間隔を置いて出鋼することを特徴とするアーク炉操業方
法である。According to a sixth aspect of the present invention, there is provided the arc furnace operating method according to any one of the first to fifth aspects, wherein at least one interval of at least 20 minutes or more is provided at the time of splitting and tapping. This is a method of operating an arc furnace, which comprises tapping steel.
【００１６】本発明においては、溶解室の上部に直結し
たシャフト型予熱室内で予熱された鉄源が、溶解室内で
の鉄源の溶解速度に見合って、自然落下して溶解室に装
入されるので、予熱室から溶解室への鉄源搬送用装置が
不要であり、予熱温度を上昇させることができる。そし
て、鉄源が溶解室と予熱室とに連続して存在する状態を
保つように予熱室への鉄源の供給を継続しながら、複数
ヒート分の多量の溶鋼量を一括して溶解するので、予熱
された鉄源の使用比率が向上すると共に、排ガスが鉄源
の充填された予熱室を通過する時間比率も高くなり、極
めて高い予熱効率で溶解することができる。In the present invention, the iron source preheated in the shaft type preheating chamber directly connected to the upper part of the melting chamber falls naturally into the melting chamber in accordance with the melting speed of the iron source in the melting chamber. Therefore, a device for transferring the iron source from the preheating chamber to the melting chamber is not required, and the preheating temperature can be increased. Then, while continuing to supply the iron source to the preheating chamber so as to maintain the state where the iron source is continuously present in the melting chamber and the preheating chamber, a large amount of molten steel for a plurality of heats is melted collectively. In addition, the use ratio of the preheated iron source is improved, and the ratio of time during which the exhaust gas passes through the preheating chamber filled with the iron source is also increased, so that the melting can be performed with extremely high preheating efficiency.
【００１７】その際に、溶解室と予熱室とに連続して存
在する鉄源の量が、１ヒートの溶鋼量の５０ｗｔ％以上
であれば、熱効率が一層向上し、そして、溶解室にコー
クス等の補助熱源と酸素ガスとを供給して、補助熱源を
燃焼させれば、燃焼熱が電力エネルギーの代替となるの
で、電力原単位を一層低減することができる。この酸素
ガスの供給量は、２５Ｎｍ3 ／ｔ以上とすることが好ま
しい。２５Ｎｍ3 ／ｔ以上とすることで、後述するよう
に、電力原単位の目標値である２５０ｋＷｈ／ｔを達成
できるからである。At this time, if the amount of iron source continuously present in the melting chamber and the preheating chamber is 50 wt% or more of the amount of molten steel in one heat, the thermal efficiency is further improved, and coke is added to the melting chamber. If the auxiliary heat source and the oxygen gas are supplied and the auxiliary heat source is burned, the combustion heat becomes a substitute for the power energy, so that the power consumption unit can be further reduced. It is preferable that the supply amount of the oxygen gas be 25 Nm 3 / t or more. This is because, as described later, 250 kWh / t, which is the target value of the power consumption unit, can be achieved by setting the power consumption to 25 Nm 3 / t or more.
【００１８】又、一括して溶解する溶鋼量は、少なくと
も４ヒート分の溶鋼量を確保することが好ましい。一括
して溶解する量が４ヒート分未満では、溶解室に最初に
装入される予熱されない鉄源の使用比率が高くなり、予
熱の効果が少なくなるためである。そして、連続鋳造等
の鋳造作業は、ヒート毎に２０分間以上の間隔をおいて
実施されるので、出鋼する際に、少なくとも１回は２０
分間以上の間隔を置いて分割して出鋼すれば、溶鋼収納
搬送容器内での待機時間が少なくなり、溶鋼の温度降下
を防止することができる。その間、残りの溶鋼は溶解室
内で保持されるが、溶鋼温度が低下した場合には、所定
の温度まで再度昇熱して出鋼することが可能であり、溶
鋼温度の低下によるトラブルを防止することができる。It is preferable that the amount of molten steel to be melted at one time is at least 4 heats. If the amount to be melted in a lump is less than 4 heats, the ratio of the non-preheated iron source initially charged into the melting chamber is increased, and the effect of the preheating is reduced. Since the casting operation such as continuous casting is performed at intervals of 20 minutes or more for each heat, at least once at the time of tapping the steel, 20 minutes or more is required.
If the tapping is performed at intervals of not less than minutes, the waiting time in the molten steel storage and transport container is reduced, and the temperature drop of the molten steel can be prevented. In the meantime, the remaining molten steel is held in the melting chamber, but when the temperature of the molten steel drops, it is possible to raise the temperature again to a predetermined temperature and start tapping, thereby preventing trouble due to the drop in the molten steel temperature. Can be.
【００１９】尚、本発明の１ヒートの溶鋼量とは、連続
鋳造等の鋳造作業に用いる取鍋等の溶鋼収納搬送容器の
１つの容器に収納される溶鋼量であり、これは鋳造作業
を実施する建物のクレーン等の吊り上げ荷重から決まる
重量である。The amount of molten steel in one heat according to the present invention is the amount of molten steel stored in one container of a molten steel storage and transfer container such as a ladle used for a casting operation such as continuous casting. It is the weight determined from the lifting load of the building crane etc. to be implemented.
【００２０】[0020]
【発明の実施の形態】本発明を図面に基づき説明する。
図１は、本発明の実施の形態の１つの例を示すアーク炉
設備の断面概略図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of an arc furnace facility showing one example of an embodiment of the present invention.
【００２１】図において、内部を耐火物で構築され、底
部に炉底電極５を備えた溶解室２の上部に、溶解室２と
直結してシャフト型の予熱室３が配置され、そして、予
熱室３で覆われない溶解室２の上部開口部は開閉自在な
炉蓋４で覆われ、この炉蓋４を貫通して溶解室２内を上
下移動可能な黒鉛製の上部電極６が設けられて直流アー
ク炉１が構築されている。In the figure, a shaft-type preheating chamber 3 is disposed directly above the melting chamber 2 at the top of the melting chamber 2 which is constructed of a refractory and has a furnace bottom electrode 5 at the bottom. The upper opening of the melting chamber 2 that is not covered by the chamber 3 is covered with a furnace lid 4 that can be opened and closed, and an upper electrode 6 made of graphite is provided that penetrates the furnace lid 4 and can move up and down in the melting chamber 2. Thus, a DC arc furnace 1 is constructed.
【００２２】予熱室３の上方には、走行台車１８に吊り
下げられた鉄源供給用バケット７が設けられ、この鉄源
供給用バケット７より、予熱室３の上部に設けた開閉自
在な鉄源供給口１６を介して予熱室３内に鉄源１０が供
給される。そして、予熱室３の上端のダクト１７は集塵
機（図示せず）に連結し、溶解室２で発生する高温の排
ガスは、予熱室３、及びダクト１７を順に通って吸引さ
れ、予熱室３内の鉄源１０は予熱され、次いで、溶解室
２内で溶解された量に見合って、溶解室２内に自由落下
して装入される。Above the preheating chamber 3, there is provided an iron source supply bucket 7 suspended from a traveling carriage 18. The iron source supply bucket 7 is provided with an openable and closable iron provided above the preheating chamber 3. The iron source 10 is supplied into the preheating chamber 3 through the source supply port 16. The duct 17 at the upper end of the preheating chamber 3 is connected to a dust collector (not shown), and the high-temperature exhaust gas generated in the melting chamber 2 is sucked through the preheating chamber 3 and the duct 17 in order, and The iron source 10 is preheated, and then falls freely into the melting chamber 2 according to the amount melted in the melting chamber 2.
【００２３】炉蓋４を貫通して、溶解室２内を上下移動
可能な酸素ガス吹き込みランス８と補助熱源吹き込みラ
ンス９とが設けられ、酸素ガス吹き込みランス８からは
酸素ガスが溶解室２内に吹き込まれ、そして、補助熱源
吹き込みランス９からは空気や窒素ガス等を搬送用ガス
として補助熱源が溶解室２内に吹き込まれる。又、溶解
室２には、その炉底に、扉１４ａで出口側を押さえ付け
られて内部にマッド剤が充填した出鋼口１４と、その側
壁に、扉１５ａで出口側を押さえ付けられて内部にマッ
ド剤が充填した出滓口１５とが設けられている。An oxygen gas blowing lance 8 and an auxiliary heat source blowing lance 9 which penetrate the furnace lid 4 and can move up and down in the melting chamber 2 are provided. The auxiliary heat source is blown from the auxiliary heat source blowing lance 9 into the melting chamber 2 using air, nitrogen gas or the like as a carrier gas. Further, the melting chamber 2 has a furnace bottom whose outlet side is pressed by a door 14a and whose inside is filled with a mud agent, and whose outlet side is pressed by a door 15a on its side wall. A slag port 15 filled with a mud agent is provided therein.
【００２４】この直流アーク炉１における操業は、先
ず、鉄源供給バケット７より予熱室３内に、鉄スクラッ
プや直接還元鉄等の鉄源１０を供給する。予熱室３内に
供給された鉄源１０は、溶解室２内にも初装入として装
入され、次いで予熱室３内を充填する。尚、溶解室２内
への初装入としての鉄源１０を均一に装入するため、炉
蓋４を開けて予熱室３と反対側の溶解室２内に鉄源１０
を装入することもできる。そして、炉底電極５と上部電
極６との間に直流電流を給電しつつ、上部電極６を昇降
させて上部電極６と炉底電極５及び装入した鉄源１０と
の間でアーク１３を発生させる。そして、発生するアー
ク熱により鉄源１０を溶解し、溶鋼１１を生成させる。
溶鋼１１の生成と共に、生石灰、蛍石等のフラックスを
溶解室２内に装入して、溶融スラグ１２を溶鋼１１上に
形成させ、溶鋼１１の酸化を防止すると共に溶鋼１１の
保温を図る。溶融スラグ１２の量が多すぎる場合には、
操業中でも出滓口１５から、排滓することができる。In operation of the DC arc furnace 1, first, an iron source 10 such as iron scrap or direct reduced iron is supplied from the iron source supply bucket 7 into the preheating chamber 3. The iron source 10 supplied into the preheating chamber 3 is also initially charged into the melting chamber 2, and then the interior of the preheating chamber 3 is filled. In order to uniformly charge the iron source 10 as the initial charge into the melting chamber 2, the furnace cover 4 is opened and the iron source 10 is placed in the melting chamber 2 on the opposite side of the preheating chamber 3.
Can also be charged. Then, while supplying a direct current between the furnace bottom electrode 5 and the upper electrode 6, the upper electrode 6 is moved up and down to form an arc 13 between the upper electrode 6, the furnace bottom electrode 5 and the inserted iron source 10. generate. Then, the iron source 10 is melted by the generated arc heat, and the molten steel 11 is generated.
Along with the generation of the molten steel 11, a flux such as quicklime or fluorite is charged into the melting chamber 2 to form a molten slag 12 on the molten steel 11, thereby preventing oxidation of the molten steel 11 and keeping the molten steel 11 warm. If the amount of the molten slag 12 is too large,
The waste can be discharged from the slag outlet 15 even during operation.
【００２５】溶鋼１１の生成する頃から、酸素ガス吹き
込みランス８及び補助熱源吹き込みランス９から、酸素
ガスと補助熱源とを溶鋼１１面又は溶融スラグ１２中に
吹き込む。補助熱源としては、安価なコークス、チャ
ー、石炭、木炭、黒鉛等の炭材を使用する。溶鋼１１中
に溶解した炭材又は溶融スラグ１２中に懸濁した炭材
と、吹き込まれる酸素ガスとが反応して燃焼熱を発生す
ると共に、反応生成物のＣＯガスが溶融スラグ１２をフ
ォーミングさせて、アーク１３が溶融スラグ１２に包ま
れるので、アークの着熱効率が上昇する。この炭材の吹
き込み量は、吹き込む酸素ガスの量に対応して決める。
即ち、吹き込まれる酸素ガスの化学等量に等しい程度の
炭材を添加する。炭材量が吹き込まれる酸素ガス量に比
べて少ないと、溶鋼１１が過剰に酸化するので好ましく
ない。酸素ガスの吹き込み量は、溶鋼トン当たり２５Ｎ
ｍ3 以上とすることが好ましい。酸素ガスの吹き込み量
が、溶鋼トン当たり２５Ｎｍ3 以上となると、後述する
ように、電力原単位は２５０ｋＷｈ／ｔ以下の低い水準
を確保することができる。From the time when the molten steel 11 is formed, oxygen gas and an auxiliary heat source are blown into the molten steel 11 surface or the molten slag 12 from the oxygen gas blowing lance 8 and the auxiliary heat source blowing lance 9. As the auxiliary heat source, an inexpensive carbon material such as coke, char, coal, charcoal, and graphite is used. The carbon material dissolved in the molten steel 11 or the carbon material suspended in the molten slag 12 reacts with the blown oxygen gas to generate combustion heat, and the reaction product CO gas forms the molten slag 12. As a result, the arc 13 is wrapped in the molten slag 12, so that the efficiency of heating the arc increases. The amount of carbon material to be blown is determined according to the amount of oxygen gas to be blown.
That is, a carbon material is added in an amount equivalent to the chemical equivalent of the oxygen gas to be blown. If the amount of carbon material is smaller than the amount of oxygen gas to be blown, the molten steel 11 is excessively oxidized, which is not preferable. Oxygen gas blowing rate is 25N per ton of molten steel
It is preferably at least m 3 . When the amount of oxygen gas blown is 25 Nm 3 or more per ton of molten steel, as described later, a low power consumption unit of 250 kWh / t or less can be secured.
【００２６】溶鋼１１の生成と共に、予熱室３内の鉄源
１０は、溶解室２内で溶解された量に見合って溶解室２
内に自由落下して減少するので、この減少分を補うため
に、鉄源供給用バケット７から予熱室３へ鉄源１０を供
給する。この鉄源１０の予熱室３内への供給は、鉄源１
０が溶解室２と予熱室３とに連続して存在する状態を保
つように、連続的又は間歇的に行う。その際に、溶解室
２と予熱室３とに連続して存在する鉄源１０の量が、１
ヒート分の溶鋼量の５０ｗｔ％以上となるようにするこ
とで、予熱効果を高めることができる。When the molten steel 11 is produced, the iron source 10 in the preheating chamber 3 is turned on in accordance with the amount of the molten steel in the melting chamber 2.
The iron source 10 is supplied from the iron source supply bucket 7 to the preheating chamber 3 in order to compensate for the decrease. The supply of the iron source 10 into the preheating chamber 3 is performed by the iron source 1
It is performed continuously or intermittently so as to maintain a state where 0 is continuously present in the melting chamber 2 and the preheating chamber 3. At this time, the amount of the iron source 10 continuously present in the melting chamber 2 and the preheating chamber 3 is 1
The preheating effect can be enhanced by setting the amount of molten steel for the heat to be 50 wt% or more.
【００２７】このようにして、溶解室２内に複数ヒート
分の溶鋼１１の量が確保され、溶解室２及び予熱室３に
残留する未溶解の鉄源１０の溶解により、所定のヒート
分に対応する溶鋼量が確保される時点で、予熱室３への
鉄源１０の供給を停止し、溶解室２及び予熱室３内の全
ての未溶解の鉄源１０を溶解し、そして、溶鋼１１を出
鋼するのに都合の良い温度に調整する。次いで、直流ア
ーク炉１を傾動させ、出鋼口１４から溶鋼１１を１ヒー
ト分ずつ、溶鋼収納搬送容器（図示せず）に分割して出
鋼する。In this manner, the amount of the molten steel 11 for a plurality of heats is secured in the melting chamber 2, and the unmelted iron source 10 remaining in the melting chamber 2 and the preheating chamber 3 is melted to a predetermined heat. When the corresponding amount of molten steel is secured, supply of the iron source 10 to the preheating chamber 3 is stopped, and all the unmelted iron sources 10 in the melting chamber 2 and the preheating chamber 3 are melted. To a temperature convenient for tapping the steel. Then, the direct current arc furnace 1 is tilted, and the molten steel 11 is divided into molten steel storage / transport containers (not shown) one by one from the tapping port 14 and tapped.
【００２８】その際に、溶解室２内で４ヒート分以上の
溶鋼量を確保すると、予熱効果を高めることができる。
又、少なくとも１回は、２０分間以上、例えば１ヒート
の鋳造時間が３０分の場合には３０分程度の間隔をおい
て出鋼することで、溶鋼収納搬送容器内での待機時間を
短くすることができる。分割出鋼により、溶解室２内の
溶鋼１１の温度が低下した場合には、再度アーク加熱し
て溶鋼温度を上昇させることもできる。尚、出鋼後にＬ
Ｆ設備等の昇温機能を有する二次精錬炉を経由してから
鋳造しても良い。At this time, if a molten steel amount of 4 heats or more is secured in the melting chamber 2, the preheating effect can be enhanced.
In addition, at least once, for example, when the casting time of one heat is 30 minutes, tapping is performed at intervals of about 30 minutes to shorten the waiting time in the molten steel storage and transport container. be able to. When the temperature of the molten steel 11 in the melting chamber 2 decreases due to the split tapping, the temperature of the molten steel can be increased by performing arc heating again. After tapping, L
Casting may be performed via a secondary smelting furnace having a temperature raising function such as an F facility.
【００２９】溶解室２内の溶鋼１１を出鋼し、溶融スラ
グ１２を排滓したら、再度鉄源１０を溶解室２内に装入
して溶解を再開する。その際に、１ヒート分程度の溶鋼
１１を溶解室２内に残留させて、次回の溶解を再開して
も良い。こうすることで、初期の溶解が促進され、溶解
効率が一層向上する。After the molten steel 11 in the melting chamber 2 is tapped and the molten slag 12 is discharged, the iron source 10 is charged into the melting chamber 2 again to resume melting. At that time, about 1 heat of the molten steel 11 may be left in the melting chamber 2 to resume the next melting. By doing so, the initial dissolution is promoted, and the dissolution efficiency is further improved.
【００３０】このようにして溶解することで、溶解室２
内への初装入の鉄源１０は予熱されないが、その後に装
入される鉄源１０は全て予熱されるので、予熱効率の極
めて高い状態でアーク炉操業を行うことができ、電力原
単位は大幅に低減可能となる。By melting in this manner, the melting chamber 2
Although the iron source 10 initially charged into the inside is not preheated, all the iron sources 10 to be charged thereafter are preheated, so that the arc furnace can be operated in an extremely high preheating efficiency state, and the power consumption is reduced. Can be greatly reduced.
【００３１】尚、上記説明では、直流アーク炉１の場合
について説明したが、交流アーク炉でも全く支障なく本
発明を適用でき、更に、上部電極６の数や、炉底電極５
等の構造の違いは、本発明の支障とならないことは言う
までもない。In the above description, the case of the DC arc furnace 1 has been described. However, the present invention can be applied to an AC arc furnace without any trouble.
Needless to say, the difference in the structure does not hinder the present invention.
【００３２】[0032]
【実施例】図１に示す直流アーク炉と、ビレット連続鋳
造機とを有する製鋼工場における実施例を以下に説明す
る。アーク炉は、溶解室が炉径７．６ｍ、高さ５．５ｍ
であり、予熱室が幅３ｍ、長さ５ｍ、高さ７ｍの直方体
形状で、炉容量が６００トンである。ビレット連続鋳造
機は、鋳片の厚み及び幅共に１７５ｍｍの５ストランド
で、鋳片引抜き速度３．５ｍ／ｍｉｎで鋳造した。取鍋
の溶鋼収納量は１００トン、即ち１ヒート分の溶鋼量は
１００トンであり、前記鋳造条件では１ヒートの鋳造時
間は約２４分である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in a steelmaking plant having a DC arc furnace shown in FIG. 1 and a billet continuous casting machine will be described below. In the arc furnace, the melting chamber has a furnace diameter of 7.6 m and a height of 5.5 m.
The preheating chamber has a rectangular parallelepiped shape having a width of 3 m, a length of 5 m, and a height of 7 m, and has a furnace capacity of 600 tons. The billet continuous casting machine was cast with 5 strands of 175 mm in both thickness and width of the slab at a slab drawing speed of 3.5 m / min. The amount of molten steel stored in the ladle is 100 tons, that is, the amount of molten steel for one heat is 100 tons, and the casting time for one heat is about 24 minutes under the above-described casting conditions.
【００３３】先ず溶解室及び予熱室内に鉄スクラップ１
５０トンを装入し、直径２８インチの黒鉛製上部電極を
用い、最大６００Ｖ、１００ＫＡの電源容量により溶解
した。溶鋼の生成と共に、生石灰と蛍石とを添加して溶
融スラグを形成し、次いで、酸素ガス吹き込みランスか
ら酸素ガスを、補助熱源吹き込みランスからコークスを
溶融スラグ中に吹き込んだ。酸素ガスとコークスの吹き
込みにより、溶融スラグはフォーミングして上部電極の
先端は溶融スラグ中に埋没した。この時の電圧を４００
Ｖに設定した。First, iron scrap 1 was placed in the melting chamber and the preheating chamber.
50 tons were charged, and melting was performed using a graphite upper electrode having a diameter of 28 inches and a maximum power supply capacity of 600 V and 100 KA. With the production of molten steel, quicklime and fluorite were added to form a molten slag, and then oxygen gas was blown into the molten slag from an oxygen gas blowing lance and coke was blown from an auxiliary heat source blowing lance. By blowing oxygen gas and coke, the molten slag formed and the tip of the upper electrode was buried in the molten slag. The voltage at this time is 400
V was set.
【００３４】予熱室内の鉄スクラップが溶解につれて下
降したら、鉄源供給用バケットにより鉄スクラップを予
熱室に供給し、予熱室内の鉄スクラップ高さを一定の高
さに保持しながら溶解を続け、溶解室内に５３０トンの
溶鋼が生成した時点で、予熱室への鉄スクラップの供給
を停止し、その後、溶解室と予熱室内の未溶解の鉄スク
ラップを完全に溶解して１６２０℃まで昇温し、６００
トン即ち６ヒート分の溶鋼を得た。When the iron scrap in the preheating chamber descends as it melts, the iron scrap is supplied to the preheating chamber by the iron source supply bucket, and the melting is continued while maintaining the height of the iron scrap in the preheating chamber at a constant level. When 530 tons of molten steel was generated in the chamber, the supply of iron scrap to the preheating chamber was stopped, and then the undissolved iron scrap in the melting chamber and the preheating chamber was completely melted and heated to 1620 ° C. 600
Ton, that is, 6 heats of molten steel was obtained.
【００３５】この溶解中、酸素ガス及びコークスの吹き
込み量を５水準に変更し、それぞれ酸素ガス原単位及び
コークス原単位を、実施例１では２０Ｎｍ3／ｔ、１６
ｋｇ／ｔ、実施例２では２５Ｎｍ3／ｔ、２０ｋｇ／
ｔ、実施例３では３３Ｎｍ3／ｔ、２６ｋｇ／ｔ、実施
例４では３８Ｎｍ3／ｔ、３０ｋｇ／ｔ、実施例５では
４５Ｎｍ3／ｔ、３６ｋｇ／ｔとして実施した。During the dissolution, the oxygen gas and coke blowing amounts were changed to five levels, and the oxygen gas basic unit and coke basic unit were respectively changed to 20 Nm 3 / t, 16
kg / t, 25 Nm 3 / t and 20 kg / t in Example 2.
t, 33 Nm 3 / t and 26 kg / t in Example 3, 38 Nm 3 / t and 30 kg / t in Example 4, and 45 Nm 3 / t and 36 kg / t in Example 5.
【００３６】次いで、５分間隔で１００トンずつ分割し
て取鍋に連続して３ヒート分を出鋼した後、溶解室内に
３００トン残留した状態で保持した。そして、３ヒート
目の出鋼開始から６５分間溶解室内で保持した後、１６
２０℃に昇温して、残りの３ヒート分の溶鋼を５分間隔
で取鍋に分割して出鋼した。ビレット連続鋳造機では、
先の３ヒートに続き、合計６ヒート分の溶鋼を連続して
鋳造した。Then, 100 tons were divided at intervals of 5 minutes and three heats were continuously output to the ladle, and then 300 tons were retained in the melting chamber. Then, after being kept in the melting chamber for 65 minutes from the start of tapping in the third heat, 16
The temperature was raised to 20 ° C., and the molten steel for the remaining three heats was divided into ladles at 5 minute intervals and tapped. In the billet continuous casting machine,
Following the previous three heats, molten steel for a total of six heats was continuously cast.
【００３７】比較のために、１００トンの鉄スクラップ
を溶解室と予熱室とに装入し、鉄スクラップの追加装入
なしに１ヒート分の溶鋼を、連続して６回バッチ溶解す
る比較例も実施した。比較例での酸素ガス原単位及びコ
ークス原単位は、それぞれ３３Ｎｍ3／ｔ、２６ｋｇ／
ｔであり、実施例３と同じ条件である。For comparison, a comparative example in which 100 tons of iron scrap is charged into a melting chamber and a preheating chamber, and molten steel for one heat is continuously and batch-melted six times without additional charging of iron scrap. Was also implemented. The oxygen gas unit consumption and the coke unit consumption in the comparative example were 33 Nm 3 / t and 26 kg / t, respectively.
t, which is the same condition as in the third embodiment.
【００３８】表１に、実施例１〜５及び比較例の操業結
果を示す。実施例１〜５共に、比較例より電力原単位が
低減し、特に、酸素ガス及びコークス原単位が同一な実
施例３との比較では、電力原単位は８５ｋＷｈ／ｔ低下
していた。又、酸素ガス原単位の高い実施例５では、比
較例に比べて１３０ｋＷｈ／ｔの電力原単位を低減する
ことができた。Table 1 shows the operation results of Examples 1 to 5 and Comparative Example. In all of Examples 1 to 5, the power consumption was reduced as compared with the comparative example. In particular, in comparison with Example 3 in which the oxygen gas and coke consumption were the same, the power consumption was reduced by 85 kWh / t. Further, in Example 5, in which the oxygen gas intensity was high, the power intensity of 130 kWh / t could be reduced as compared with the comparative example.
【００３９】[0039]
【表１】 [Table 1]
【００４０】又、図２に、実施例１〜５において得られ
た電力原単位に及ぼす酸素ガス原単位の影響を示す。図
に示すように酸素ガス原単位が増加するに従い電力原単
位は低減し、電力原単位の目標を２５０ｋＷｈ／ｔとす
ると、２５０ｋＷｈ／ｔを達成するためには、酸素ガス
原単位を２５Ｎｍ3／ｔ以上とすれば良いことが分かっ
た。このように、本発明により予熱効果が向上し、電力
原単位を大幅に低減することができた。FIG. 2 shows the influence of the oxygen gas intensity on the power intensity obtained in Examples 1 to 5. As shown in the figure, the power consumption decreases as the oxygen gas consumption increases, and the target power consumption is 250 kWh / t. To achieve 250 kWh / t, the oxygen gas consumption is 25 Nm 3 / t. It has been found that it should be at least t. As described above, the preheating effect was improved by the present invention, and the power consumption rate was significantly reduced.
【００４１】[0041]
【発明の効果】本発明では、溶解室と直結した予熱室を
有するアーク炉にて、鉄源が溶解室と予熱室とに連続し
て存在する状態を保ちつつ鉄源を予熱し、複数ヒート分
の溶鋼を一括して溶解するので、予熱室から溶解室への
鉄源搬送用装置を必要とせずに予熱温度を高めることが
可能であり、且つ、予熱された鉄源の使用比率が高くな
ると共に、高温の排ガスが鉄源の充填された予熱室を通
過する時間比率も高くなり、極めて高い予熱効率で溶解
することができ、その結果、電力原単位を大幅に低減す
ることができる。According to the present invention, in an arc furnace having a preheating chamber directly connected to a melting chamber, the iron source is preheated while maintaining a state in which the iron source is continuously present in the melting chamber and the preheating chamber. Since the molten steel is melted all at once, the preheating temperature can be increased without the need for a device for transporting the iron source from the preheating chamber to the melting chamber, and the usage ratio of the preheated iron source is high. At the same time, the ratio of the time during which the high-temperature exhaust gas passes through the preheating chamber filled with the iron source is increased, so that the melting can be performed with extremely high preheating efficiency. As a result, the power consumption can be significantly reduced.
【図１】本発明の実施の形態の１つの例を示すアーク炉
設備の断面概略図である。FIG. 1 is a schematic cross-sectional view of an arc furnace facility showing one example of an embodiment of the present invention.
【図２】実施例から得られた電力原単位に及ぼす酸素ガ
ス原単位の影響を示す図である。FIG. 2 is a diagram showing the influence of oxygen gas intensity on power intensity obtained from an example.
１ 直流アーク炉 ２ 溶解室 ３ 予熱室 ４ 炉蓋 ５ 炉底電極 ６ 上部電極 ７ 鉄源供給用バケット ８ 酸素ガス吹き込みランス ９ 補助熱源吹き込みランス １０ 鉄源 １１ 溶鋼 １２ 溶融スラグ １３ アーク DESCRIPTION OF SYMBOLS 1 DC arc furnace 2 Melting room 3 Preheating room 4 Furnace lid 5 Furnace bottom electrode 6 Upper electrode 7 Iron source supply bucket 8 Oxygen gas blowing lance 9 Auxiliary heat source blowing lance 10 Iron source 11 Molten steel 12 Melting slag 13 Arc
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｆ２７Ｄ 17/00 １０１ Ｆ２７Ｄ 17/00 １０１Ｇ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI F27D 17/00 101 F27D 17/00 101G
Claims (6)
の予熱室とを有し、溶解室で発生する排ガスを予熱室に
導入して鉄スクラップ等の鉄源を予熱して溶解するアー
ク炉の操業方法において、鉄源が溶解室と予熱室とに連
続して存在する状態を保つように予熱室への鉄源の供給
を継続しながら溶解室内の鉄源を溶解し、溶解室に複数
ヒート分の溶鋼量が確保された時点で予熱室への鉄源の
供給を停止し、次いで、溶解室及び予熱室内の未溶解の
鉄源を全て溶解した後、１ヒート分の溶鋼量ずつ分割し
て出鋼することを特徴とするアーク炉操業方法。1. An arc having a melting chamber and a shaft-type preheating chamber directly connected to the melting chamber, wherein an exhaust gas generated in the melting chamber is introduced into the preheating chamber to preheat and melt an iron source such as iron scrap. In the operation method of the furnace, the iron source in the melting chamber is melted while the supply of the iron source to the preheating chamber is continued so that the iron source is continuously present in the melting chamber and the preheating chamber. When the amount of molten steel for a plurality of heats is secured, supply of the iron source to the preheating chamber is stopped, and then all the unmelted iron sources in the melting chamber and the preheating chamber are melted. An arc furnace operation method comprising splitting and tapping.
源の量が、１ヒートの溶鋼量の５０ｗｔ％以上であるこ
とを特徴とする請求項１に記載のアーク炉操業方法。2. The arc furnace operating method according to claim 1, wherein the amount of the iron source continuously present in the melting chamber and the preheating chamber is 50 wt% or more of the molten steel amount in one heat.
解室内に供給することを特徴とする請求項１又は請求項
２に記載のアーク炉操業方法。3. The arc furnace operating method according to claim 1, wherein an auxiliary heat source such as coke and oxygen gas are supplied into the melting chamber.
以上であることを特徴とする請求項３に記載のアーク炉
操業方法。4. An oxygen gas supply rate of 25 Nm 3 / t
The method for operating an arc furnace according to claim 3, wherein:
量を確保することを特徴とする請求項１ないし請求項４
の何れか１つに記載のアーク炉操業方法。5. The molten steel volume for the heat of at least 4 heats is secured in the melting chamber before tapping.
The arc furnace operating method according to any one of the above.
は２０分間以上の間隔を置いて出鋼することを特徴とす
る請求項１ないし請求項５の何れか１つに記載のアーク
炉操業方法。6. The arc according to claim 1, wherein the tapping is performed at least once at intervals of 20 minutes or more when tapping is performed separately. Furnace operation method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20755997A JP3814768B2 (en) | 1997-08-01 | 1997-08-01 | Arc furnace operation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20755997A JP3814768B2 (en) | 1997-08-01 | 1997-08-01 | Arc furnace operation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1151574A true JPH1151574A (en) | 1999-02-26 |
| JP3814768B2 JP3814768B2 (en) | 2006-08-30 |
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ID=16541751
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20755997A Expired - Fee Related JP3814768B2 (en) | 1997-08-01 | 1997-08-01 | Arc furnace operation method |
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| Country | Link |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012007105A1 (en) | 2010-07-14 | 2012-01-19 | Tenova S.P.A. | Continuous feeding system to a smelting furnace of pre-heated metal material, in continuous, potentiated and combined form |
-
1997
- 1997-08-01 JP JP20755997A patent/JP3814768B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012007105A1 (en) | 2010-07-14 | 2012-01-19 | Tenova S.P.A. | Continuous feeding system to a smelting furnace of pre-heated metal material, in continuous, potentiated and combined form |
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| Publication number | Publication date |
|---|---|
| JP3814768B2 (en) | 2006-08-30 |
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