JPH08232009A - Preliminary refining method - Google Patents
Preliminary refining methodInfo
- Publication number
- JPH08232009A JPH08232009A JP3537495A JP3537495A JPH08232009A JP H08232009 A JPH08232009 A JP H08232009A JP 3537495 A JP3537495 A JP 3537495A JP 3537495 A JP3537495 A JP 3537495A JP H08232009 A JPH08232009 A JP H08232009A
- Authority
- JP
- Japan
- Prior art keywords
- flux
- gas
- carrier gas
- treatment
- melting
- 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
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、上吹き転炉型の精錬炉
において配合率15％以下の冷鉄源の完全溶解と脱 P処理
を実施する予備精錬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 a pre-refining method for performing complete melting and de-P treatment of a cold iron source having a mixing ratio of 15% or less in a top-blown converter type refining furnace.
【０００２】[0002]
【従来の技術】転炉等の酸素精錬設備を用いて少量のス
クラップ等の冷鉄源を溶解する場合、熱源として脱Si反
応や脱 C反応の酸化反応熱を用いている。一方、溶銑状
態における冷鉄源の溶解は溶銑中の Cが冷鉄源中に拡散
し、冷鉄源の融点を低下させることにより進行する。そ
のため、冷鉄源溶解を進行させるためには、鉄浴の強攪
拌により絶えず冷鉄源表面に Cを供給することが必要で
ある。この強攪拌の結果、上吹き酸素等により酸化度を
高められたカバースラグの酸化度が低下し、冷鉄源溶解
中には脱 P反応が殆ど進行しない。したがって、従来、
冷鉄源溶解完了後に、上吹き酸素等により酸化度を高め
られたカバースラグが溶銑中の Cにより還元されない程
度まで鉄浴の攪拌を低下させることで脱 P処理を実施し
ている。2. Description of the Related Art When a small amount of cold iron source such as scrap is melted by using oxygen refining equipment such as a converter, the heat of oxidation reaction of de-Si reaction or de-C reaction is used as a heat source. On the other hand, the dissolution of the cold iron source in the hot metal state progresses when C in the hot metal diffuses into the cold iron source and lowers the melting point of the cold iron source. Therefore, in order to promote the dissolution of the cold iron source, it is necessary to constantly supply C to the surface of the cold iron source by vigorous stirring in the iron bath. As a result of this strong stirring, the degree of oxidation of the cover slag whose degree of oxidation has been increased by top-blown oxygen and the like decreases, and the de-P reaction hardly progresses during the melting of the cold iron source. Therefore, conventionally,
After the completion of melting of the cold iron source, deoxidation treatment is carried out by lowering the stirring of the iron bath until the cover slag whose degree of oxidation has been increased by top-blown oxygen etc. is not reduced by C in the hot metal.
【０００３】[0003]
【発明が解決しようとする課題】上記のように、冷鉄源
溶解を進行させるためには、鉄浴の強攪拌により絶えず
冷鉄源表面に Cを供給することが必要である。そして、
鉄浴を強攪拌することにより、上吹き酸素等により酸化
度を高められたカバースラグへ溶銑中の Cが絶えず供給
され、カバースラグ中に生成された酸化鉄が還元され
る。その結果、カバースラグ形成のために添加された生
石灰等の脱 Pフラックスの溶解が妨げられ、脱 Pは殆ど
進行しない。そこで、冷鉄源溶解完了後に上吹き酸素等
により酸化度を高められたカバースラグが溶銑中の Cに
より還元されない程度まで鉄浴の攪拌を低下させること
で脱 P処理を実施している。As described above, in order to promote the dissolution of the cold iron source, it is necessary to constantly supply C to the surface of the cold iron source by vigorous stirring of the iron bath. And
By vigorously stirring the iron bath, C in the hot metal is constantly supplied to the cover slag whose degree of oxidation has been increased by top-blown oxygen and the iron oxide produced in the cover slag is reduced. As a result, the dissolution of the de-P flux such as quicklime added to form the cover slag is hindered, and the de-P process hardly progresses. Therefore, after the completion of melting of the cold iron source, the deoxidation treatment is carried out by reducing the stirring of the iron bath until the cover slag whose degree of oxidation has been increased by top-blown oxygen etc. is not reduced by C in the hot metal.
【０００４】以上のように、従来は、上下吹き転炉タイ
プの精錬炉において底吹羽口を用いて鉄浴を攪拌するガ
ス量を脱 Pのための低流量領域から冷鉄源溶解のための
高流量領域までの範囲で制御していた。As described above, conventionally, in a smelting furnace of the vertical blowing converter type, the amount of gas for stirring the iron bath using the bottom blowing port is changed from the low flow rate region for de-Ping to the cold iron source melting. It was controlled in the range up to the high flow rate region.
【０００５】しかしながら、底吹羽口を用いた場合、安
定した吹込みガス流量の制御が可能な範囲は、最低流量
から最低流量の約５倍までの範囲であるので、脱 Pある
いは冷鉄源溶解のどちらか一方の精錬機能を犠牲にしな
がら底吹操業しているのが実情である。However, when the bottom blower is used, the range in which the stable control of the blown gas flow rate is possible is from the minimum flow rate to about 5 times the minimum flow rate, and therefore, there is no P or cold iron source. The reality is that bottom blowing operations are performed while sacrificing either refining function of melting.
【０００６】本発明は、上記の問題点を解決するために
なされたもので、一つの精錬炉において、冷鉄源溶解処
理と脱 P処理という相反する精錬処理を同時に満足する
予備精錬方法を提供することを目的とする。The present invention has been made to solve the above problems, and provides a pre-refining method that simultaneously satisfies the contradictory refining treatments of a cold iron source melting treatment and a de-P treatment in one refining furnace. The purpose is to do.
【０００７】[0007]
【課題を解決するための手段】本発明の要旨は、上吹き
転炉型の酸素精錬炉を用い、 C濃度が 3％以上の溶銑状
態で配合率15％以下の冷鉄源の完全溶解と脱 P処理を行
うに際し、前半の冷鉄源溶解期において、鉄浴中に浸漬
した耐火物ランスから、キャリアガスとフラックスの分
解反応により発生する CO2ガス量の合計が 0.2〜0.5Nm3
/min・t の範囲になるようにキャリアガスとともに前記
フラックスを吹込み、同時に鉄浴表面に生成するカバー
スラグの塩基度が 1.5〜2.5 の範囲になるように調整し
た脱 Pフラックスを脱Si反応が完了するまで上方あるい
は耐火物ランスから添加し、冷鉄源溶解完了後の後半の
脱 P期において、鉄浴中に浸漬した耐火物ランスから、
キャリアガスとフラックスの分解反応により発生する C
O2ガス量の合計が 0.05Nm3/min・t 以下になるようにキ
ャリアガスとともに前記フラックスを吹込むことを特徴
とする予備精錬方法である。[Means for Solving the Problems] The gist of the present invention is to use a top-blown converter type oxygen smelting furnace to completely melt a cold iron source with a blending ratio of 15% or less in a hot metal state with a C concentration of 3% or more. During de-P treatment, the total amount of CO 2 gas generated by the decomposition reaction of carrier gas and flux from the refractory lance immersed in the iron bath during the first half of the cold iron source melting period was 0.2 to 0.5 Nm 3
The above flux was blown together with the carrier gas so that it would be in the range of / min ・ t, and at the same time, the basicity of the cover slag generated on the iron bath surface was adjusted to be in the range of 1.5 to 2.5. Is added from above or from the refractory lance until completion, and from the refractory lance soaked in the iron bath in the second half P removal period after the completion of melting the cold iron source,
C generated by decomposition reaction of carrier gas and flux
The preliminary refining method is characterized in that the flux is blown together with a carrier gas so that the total amount of O 2 gas becomes 0.05 Nm 3 / min · t or less.
【０００８】[0008]
【作用】本発明の予備精錬方法は、前半の冷鉄源溶解期
と後半の脱 P期の二期に別れ、前半の冷鉄源溶解期で
は、冷鉄源溶解と同時に脱Si反応が進行する。冷鉄源溶
解期では、鉄浴中に浸漬した耐火物ランスから、キャリ
アガスとフラックスの分解反応により発生する CO2ガス
量の合計が 0.2〜0.5Nm3/min・t の範囲になるようにキ
ャリアガスとともに前記フラックスを吹込み、同時に鉄
浴表面に生成するカバースラグの塩基度が 1.5〜2.5 の
範囲になるように調整した脱 Pフラックスを脱Si反応が
完了するまで上方あるいは耐火物ランスから添加する。[Function] The pre-refining method of the present invention is divided into the first half of the cold iron source melting period and the second half of the de-P period, and in the first half of the cold iron source melting period, the de-Si reaction proceeds simultaneously with the melting of the cold iron source. To do. During the cold iron source melting period, the total amount of CO 2 gas generated by the decomposition reaction of carrier gas and flux from the refractory lance immersed in the iron bath should be in the range of 0.2 to 0.5 Nm 3 / min ・ t. The flux is blown together with the carrier gas, and at the same time, the basicity of the cover slag generated on the iron bath surface is adjusted to be in the range of 1.5 to 2.5.Remove the de-P flux from above or from the refractory lance until the de-Si reaction is completed. Added.
【０００９】冷鉄源溶解期に耐火物ランスから吹込むフ
ラックスは、鉄浴中に吹込む際に分解反応して CO2ガス
を生じる物質を含むフラックスで、フラックスにCaCO3
を使用する場合の分解反応は、CaCO3 →CaO ＋CO2 であ
る。また、フラックス中にはCaCO3 以外に酸化鉄系の物
質が含まれることが望ましいが、酸化鉄系の配合率は0
％でもかまわない。酸化鉄系の物質を含む混合フラック
スの組成はCaCO3 ＋(FeO・Fe2O3)である。The flux blown from the refractory lance during the melting period of the cold iron source is a flux containing a substance that decomposes to produce CO 2 gas when blown into the iron bath, and CaCO 3 is added to the flux.
The decomposition reaction when using is CaCO 3 → CaO + CO 2 . It is desirable that the flux contains iron oxide-based substances in addition to CaCO 3 , but the iron oxide-based compounding ratio is 0
% Does not matter. The composition of the mixed flux containing the iron oxide-based substance is CaCO 3 + (FeO · Fe 2 O 3 ).
【００１０】上記フラックスを鉄浴中に吹込む際のキャ
リアガスとフラックスの分解反応により発生する CO2ガ
ス量の合計を 0.2〜0.5Nm3/min・t の範囲に限定した理
由は以下の通りである。下限である0.2Nm3/min・t は溶
銑状態でスクラップを短時間で溶解するために必要な量
で、一方、上限である0.5Nm3/min・t は鉄浴中に添加さ
れたガスによる溶銑飛散 (スプラッシュ) が操業に支障
を生じる限界 (精錬炉内に地金が付着し、操業ができな
くなる限界) である。キャリアガスには窒素等の不活性
ガスを使用する。The reason why the total amount of the CO 2 gas generated by the decomposition reaction of the carrier gas and the flux when the above flux is blown into the iron bath is limited to the range of 0.2 to 0.5 Nm 3 / min · t is as follows. Is. The lower limit of 0.2 Nm 3 / min ・ t is the amount required to melt scrap in a hot metal state in a short time, while the upper limit of 0.5 Nm 3 / min ・ t depends on the gas added to the iron bath. It is the limit at which the hot metal splash (splash) interferes with the operation (the limit at which the metal cannot adhere to the refining furnace due to the adhesion of metal). An inert gas such as nitrogen is used as the carrier gas.
【００１１】鉄浴表面に生成するカバースラグの塩基度
を 1.5〜2.5 の範囲に限定した理由は以下の通りであ
る。下限である塩基度 1.5は、脱 P反応を効率よく進行
させるための塩基度であり、一方、上限である塩基度
2.5は、溶銑温度 (1300〜1350℃) の状態において溶融
スラグを形成するための塩基度で 2.5以下であることが
望ましい。ただし、蛍石などの滓化促進剤を併用すれば
この限りではないが、精錬炉内側の耐火物溶解も促進す
るという問題を生じる。カバースラグの組成はT.Fe:3〜
7 ％、CaO:30〜40％、 SiO2:15〜25％である。The reason why the basicity of the cover slag formed on the iron bath surface is limited to the range of 1.5 to 2.5 is as follows. The basicity of 1.5, which is the lower limit, is the basicity for promoting the de-P reaction efficiently, while the basicity, which is the upper limit, is the basicity.
2.5 is a basicity for forming molten slag at a hot metal temperature (1300 to 1350 ° C), and is preferably 2.5 or less. However, if a slag formation accelerator such as fluorite is also used in combination, there is a problem in that the melting of the refractory inside the refining furnace is also promoted, although not limited thereto. The composition of the cover slag is T.Fe: 3〜
7%, CaO: 30~40%, SiO 2: from 15 to 25%.
【００１２】カバースラグの塩基度を 1.5〜2.5 の範囲
になるように調整する脱 PフラックスはCaO 系のフラッ
クスである。CaO 以外にガス発生を伴うCaO 系のCaCO3
を混合したものでもよい。また、フラックス中にはCaCO
3 以外に酸化鉄系の物質が含まれることが望ましいが、
酸化鉄系の配合率は 0％でもかまわない。CaO 系のCaCO
3 と酸化鉄系の物質を含む混合フラックスの組成はCaO
＋CaCO3 ＋(FeO・Fe2O 3)である。The basicity of the cover slag is in the range of 1.5 to 2.5
The de-P flux to be adjusted to
It's a cus. CaCO-based CaCO with gas generation other than CaO3
It may be a mixture of. Also, CaCO in the flux
3Besides, it is desirable to contain iron oxide-based substances,
The iron oxide-based compounding ratio may be 0%. CaO-based CaCO
3The composition of the mixed flux containing iron and iron oxide-based substances is CaO
＋ CaCO3＋ (FeO ・ Fe2O 3).
【００１３】上記、脱 Pフラックスを脱Si反応が完了す
るまで上方あるいは耐火物ランスから添加する。上方か
ら添加する場合のフラックスは、塊状の生石灰あるいは
石灰石で、精錬炉上部のホッパーから鉄浴表面に落下さ
せて添加する。もちろん耐火物ランスから添加する場合
のフラックスは粉末状である。The above-mentioned P-free flux is added from above or from the refractory lance until the Si-removing reaction is completed. When added from above, the flux is lumpy quicklime or limestone, which is dropped from the hopper in the upper part of the refining furnace and added to the surface of the iron bath. Of course, the flux when added from the refractory lance is in powder form.
【００１４】冷鉄源溶解完了後の後半の脱 P期におい
て、鉄浴中に浸漬した耐火物ランスから、キャリアガス
とフラックスの分解反応により発生する CO2ガス量の合
計が 0.05Nm3/min・t 以下になるようにキャリアガスと
ともに前記フラックスを吹込む。In the latter half of the P removal period after the completion of melting of the cold iron source, the total amount of CO 2 gas generated by the decomposition reaction of the carrier gas and the flux from the refractory lance immersed in the iron bath was 0.05 Nm 3 / min.・ Blow in the above flux together with the carrier gas so that it becomes t or less.
【００１５】脱 P反応終了後のカバースラグの組成は、
T.Fe:10〜15％、CaO:30〜40％、 SiO2:15〜25％であ
る。脱 P反応を進行させるためには、前記のカバースラ
グを鉄浴表面に形成する必要がある。しかしながら、鉄
浴を強攪拌した場合、鉄浴中のCによりカバースラグ中
の酸化鉄が還元され、スラグの脱 P反応特性が低下す
る。一方、脱 P期にスラグの脱 P反応特性を向上させる
ためには、スラグ中の酸化鉄濃度をT.Feで10〜15％程度
の範囲に維持する必要がある。そこで、鉄浴の攪拌強度
を低下し、鉄浴中 Cによるカバースラグ中の酸化鉄の還
元を抑制するために、鉄浴中へ吹込むガス量はキャリア
ガスとフラックスの分解反応により発生するCO2ガス量
の合計を 0.05Nm3/min・t 以下に低減する必要がある。The composition of the cover slag after the de-P reaction is
T.Fe: 10 to 15%, CaO: 30 to 40%, SiO 2 : 15 to 25%. In order to proceed the de-P reaction, it is necessary to form the cover slag on the iron bath surface. However, when the iron bath is vigorously stirred, the iron oxide in the cover slag is reduced by C in the iron bath, and the de-P reaction characteristics of the slag deteriorate. On the other hand, in order to improve the de-P reaction characteristics of slag during the de-P period, it is necessary to maintain the iron oxide concentration in the slag within the range of 10 to 15% in T.Fe. Therefore, in order to reduce the stirring strength of the iron bath and suppress the reduction of iron oxide in the cover slag by C in the iron bath, the amount of gas blown into the iron bath is CO generated by the decomposition reaction of carrier gas and flux. It is necessary to reduce the total amount of 2 gases to 0.05 Nm 3 / min · t or less.
【００１６】脱 P期において、鉄浴中に吹込むフラック
スは CaO系フラックスである。ただし、鉄浴の攪拌強度
を低下させる観点から、ガス発生を伴う CaO系の物質Ca
CO3の混合比率は極力少ない物が望まれる。また、フラ
ックス中に酸化鉄系の物質が含まれることが望ましい
が、酸化鉄系の配合率は 0％でもかまわない。In the de-P period, the flux blown into the iron bath is CaO type flux. However, from the viewpoint of reducing the stirring strength of the iron bath, the CaO-based substance Ca
It is desirable that the mixing ratio of CO 3 be as small as possible. Further, although it is desirable that the flux contains an iron oxide-based substance, the iron oxide-based compounding ratio may be 0%.
【００１７】上記のように、本発明の予備精錬方法は、
前半の冷鉄源溶解期には鉄浴攪拌状態を十分に高め、冷
鉄源を溶解し、後半の脱 P期においては、鉄浴表面のカ
バースラグのT.Feが10％以上確保できるまで鉄浴攪拌状
態を抑え、脱 Pすることができる。それ故に、冷鉄源溶
解処理と脱 P処理という相反する精錬反応を一つの精錬
炉で実施することができる。As mentioned above, the pre-refining method of the present invention comprises:
In the first half of the cold iron source melting period, the iron bath stirring state was sufficiently raised to melt the cold iron source, and in the latter half of the de-P period, T.Fe of the cover slag on the iron bath surface was kept at 10% or more. It is possible to remove P by suppressing the stirring condition in the iron bath. Therefore, the contradictory refining reactions of cold iron source melting treatment and de-P treatment can be carried out in one refining furnace.
【００１８】[0018]
【実施例】本発明の実施例を図面を参照しながら説明す
るが、これによって本発明は何ら限定されるものではな
い。図１は耐火物ランス浸漬設備を有する転炉型の精錬
炉の縦断面図である。また、図２は本発明を適用した場
合の処理パターンの一例を示したものである。Embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a vertical cross-sectional view of a converter type refining furnace having a refractory lance immersion facility. Further, FIG. 2 shows an example of a processing pattern when the present invention is applied.
【００１９】まず、Siを0.25％含有する溶銑90t と5tの
スクラップを図１に示した精錬炉に装入し、耐火物ラン
スから鉄浴攪拌ガス流量が0.5Nm3/min・t を確保するた
め石灰石を 2.2kg/min・t の速度で供給し、同時に処理
後スラグの塩基度が 2になるように上方からカバースラ
グ形成用フラックス (塊状石灰石2.5kg/t)と固体酸素源
(鉄鉱石)13kg/t を溶銑中に投入した。また、同時に酸
素ランスを介して、酸素ガスを1.5Nm3/min・t の割合で
4分間連続的に溶銑に吹きつけた。First, 90 tons of hot metal containing 0.25% of Si and 5 tons of scrap are charged into the refining furnace shown in FIG. 1, and the flow rate of the iron bath agitating gas is 0.5 Nm 3 / min · t from the refractory lance. Therefore, limestone is supplied at a rate of 2.2 kg / min ・ t, and at the same time, the flux for forming cover slag (lump limestone 2.5 kg / t) and solid oxygen source are applied from above so that the basicity of the slag after treatment is 2.
(Iron ore) 13 kg / t was put into the hot metal. At the same time, oxygen gas is supplied through the oxygen lance at a rate of 1.5 Nm 3 / min ・ t.
It was continuously sprayed on the hot metal for 4 minutes.
【００２０】冷鉄源溶解が完了した時点で酸素ランスか
ら吹きつけている酸素ガスの供給量を0.5Nm3/min・t ま
で低下し、耐火物ランスから鉄浴中へ吹込むフラックス
を石灰石から生石灰へ切り替え、さらに 4分間脱 P処理
を実施した。図３に本実施例の溶銑成分の経時変化を、
表１に処理前後の成分組成と処理後のスラグ中のT.Feと
塩基度をそれぞれ示す。When the melting of the cold iron source is completed, the supply amount of oxygen gas blown from the oxygen lance is reduced to 0.5 Nm 3 / min · t, and the flux blown from the refractory lance into the iron bath is changed from limestone. After switching to quicklime, dephosphorization treatment was performed for 4 minutes. FIG. 3 shows the changes over time in the hot metal component of this example.
Table 1 shows the component composition before and after the treatment, and T.Fe and basicity in the slag after the treatment, respectively.
【００２１】図３および表１に示すように、脱 P処理の
初期段階から溶銑表面にT.Feの高いカバースラグが生成
され、処理開始 8分後には溶銑中の P濃度が 0.100％か
ら 0.015％まで低下している。As shown in FIG. 3 and Table 1, a cover slag having a high T.Fe content was formed on the surface of the hot metal from the initial stage of the dephosphorization treatment, and 8 minutes after the start of the treatment, the P concentration in the hot metal was 0.100% to 0.015%. It has fallen to%.
【００２２】[0022]
【表１】 [Table 1]
【００２３】比較例１ 図４は比較例１として、Siを0.25％含有する溶銑90t と
5tのスクラップを精錬炉に装入し、冷鉄源溶解期には底
吹羽口から0.3Nm3/min・t の窒素ガスを流し、同時に処
理後スラグの塩基度が 2になるように上方からカバース
ラグ形成用フラックス (塊状石灰石11.5kg/t) と固体酸
素源 (鉄鉱石)13kg/t を溶銑中に投入した。また、同時
に酸素ランスを介して、酸素ガスを1.5Nm3/min・t の割
合で 7分間連続的に溶銑に吹きつけた。COMPARATIVE EXAMPLE 1 FIG. 4 shows Comparative Example 1 in which 90 g of hot metal containing 0.25% Si was used.
5 tons of scrap was charged into the refining furnace, and 0.3 Nm 3 / min ・ t of nitrogen gas was flowed from the bottom blower mouth during the cold iron source melting period, and at the same time, after the treatment, the slag had a basicity of 2 From above, a flux for forming cover slag (lump limestone 11.5 kg / t) and a solid oxygen source (iron ore) 13 kg / t were charged into the hot metal. At the same time, oxygen gas was continuously sprayed onto the hot metal at a rate of 1.5 Nm 3 / min · t for 7 minutes through an oxygen lance.
【００２４】冷鉄源溶解が完了した時点で酸素ランスか
ら吹きつけている酸素ガスの供給量を0.5Nm3/min・t ま
で低下すると同時に底吹ガス流量を 0.06Nm3/min・t ま
で低下し、さらに 4分間脱 P処理を実施した。図５に比
較例１の溶銑成分の経時変化を、表２に処理前後の成分
組成と処理後（一次吹止）のスラグ中のT.Feと塩基度を
それぞれ示す。When the cold iron source is completely melted, the supply rate of oxygen gas blown from the oxygen lance is reduced to 0.5 Nm 3 / min ・ t, and at the same time, the bottom blown gas flow rate is reduced to 0.06 Nm 3 / min ・ t. Then, de-P treatment was performed for another 4 minutes. FIG. 5 shows the change with time of the hot metal component of Comparative Example 1, and Table 2 shows the component composition before and after the treatment and T.Fe and basicity in the slag after the treatment (primary blow stop), respectively.
【００２５】図５および表２に示すように、0.3Nm3/min
・t 程度の鉄浴強攪拌条件下においては、冷鉄源溶解完
了時期が処理開始後 7分程度まで遅れるため、溶銑表面
に脱P能を持つ溶融スラグ層が形成される時期が遅れ、
処理開始 8分後では溶銑中のP濃度が 0.100％から 0.04
0％までしか低下しない。As shown in FIG. 5 and Table 2, 0.3 Nm 3 / min
・ Under the condition of strong stirring in the iron bath of about t, the completion time of the cold iron source dissolution is delayed until about 7 minutes after the start of the treatment, so the time when the molten slag layer with the de-P capability is formed on the hot metal surface is delayed.
Eight minutes after the start of the treatment, the P concentration in the hot metal changed from 0.100% to 0.04%.
It only drops to 0%.
【００２６】[0026]
【表２】 [Table 2]
【００２７】比較例２ 図６は比較例２として、Siを0.25％含有する溶銑90t と
5tのスクラップを精錬炉に装入し、冷鉄源溶解期には底
吹羽口から0.5Nm3/min・t の窒素ガスを流し、同時に処
理後スラグの塩基度が 2になるように上方からカバース
ラグ形成用フラックス (塊状石灰石11.5kg/t) と固体酸
素源 (鉄鉱石)13kg/t を溶銑中に投入した。また、同時
に酸素ランスを介して、酸素ガスを1.5Nm3/min・t の割
合で 4分間連続的に溶銑に吹きつけた。Comparative Example 2 FIG. 6 shows Comparative Example 2 in which 90 t of hot metal containing 0.25% of Si was used.
5 ton of scrap was charged into the refining furnace, 0.5Nm 3 / min ・ t of nitrogen gas was made to flow from the bottom blower mouth during the cold iron source melting period, and at the same time, after processing, the slag had a basicity of 2 From above, a flux for forming cover slag (lump limestone 11.5 kg / t) and a solid oxygen source (iron ore) 13 kg / t were charged into the hot metal. At the same time, oxygen gas was continuously sprayed onto the hot metal at a rate of 1.5 Nm 3 / min · t for 4 minutes through an oxygen lance.
【００２８】冷鉄源溶解が完了した時点で酸素ランスか
ら吹きつけている酸素ガスの供給量を0.5Nm3/min・t ま
で低下すると同時に底吹ガス流量を0.1Nm3/min・t まで
低下し、さらに 4分間脱 P処理を実施した。図７に比較
例２の溶銑成分の経時変化を、表３に処理前後の成分組
成と処理後のスラグ中のT.Feと塩基度をそれぞれ示す。[0028] When the melting of the cold iron source is completed, the supply amount of the oxygen gas blown from the oxygen lance is reduced to 0.5 Nm 3 / min · t, and at the same time, the bottom blowing gas flow rate is reduced to 0.1 Nm 3 / min · t. Then, de-P treatment was performed for another 4 minutes. FIG. 7 shows the change with time of the hot metal component of Comparative Example 2, and Table 3 shows the component composition before and after the treatment and T.Fe and basicity in the slag after the treatment, respectively.
【００２９】図７および表３に示すように、脱 P期の底
吹ガス流量が0.1Nm3/min・t と大きいためにカバースラ
グ中のT.Feを脱 Pに必要なレベルまで確保できなくな
り、処理開始 8分後でも溶銑中の P濃度が 0.100％から
0.035％までしか低下しない。As shown in FIG. 7 and Table 3, since the bottom blowing gas flow rate in the de-P period is as large as 0.1 Nm 3 / min · t, T.Fe in the cover slag can be secured to the level required for de-P. Even after 8 minutes from the start of processing, the P concentration in the hot metal is 0.100%
It only drops to 0.035%.
【００３０】[0030]
【表３】 [Table 3]
【００３１】上記のように、本発明では処理の前半と後
半において効率よく鉄浴の攪拌状態を制御でき、脱 P処
理時のカバースラグの酸素ポテンシャルを脱 P反応が高
速に進むレベルまで確保でき、処理時間 8分で低 P溶銑
の製造ができた。As described above, according to the present invention, the stirring state of the iron bath can be efficiently controlled in the first half and the latter half of the treatment, and the oxygen potential of the cover slag during the de-P treatment can be secured to a level at which the de-P reaction proceeds rapidly. It was possible to manufacture low P hot metal in 8 minutes.
【００３２】[0032]
【発明の効果】以上述べたところから明らかなように、
本発明によれば一つの精錬炉において、冷鉄源溶解処理
と脱 P処理という相反する予備精錬処理を同時に実施す
ることが可能となる。As is apparent from the above description,
According to the present invention, in one refining furnace, it is possible to simultaneously perform the contradictory preliminary refining treatments of the cold iron source melting treatment and the de-P treatment.
【図１】耐火物ランス浸漬設備を有する転炉型の精錬炉
の縦断面図である。FIG. 1 is a vertical sectional view of a converter-type refining furnace having refractory lance immersion equipment.
【図２】本発明を適用した場合の処理パターンの一例を
示した図である。FIG. 2 is a diagram showing an example of a processing pattern when the present invention is applied.
【図３】本実施例の溶銑成分の経時変化を示す図であ
る。FIG. 3 is a view showing a change with time of a hot metal component in this example.
【図４】比較例１の処理パターンの一例を示す図であ
る。FIG. 4 is a diagram showing an example of a processing pattern of Comparative Example 1.
【図５】比較例１の溶銑成分の経時変化を示す図であ
る。FIG. 5 is a view showing a change with time of a hot metal component of Comparative Example 1.
【図６】比較例２の処理パターンの一例を示す図であ
る。6 is a diagram showing an example of a processing pattern of Comparative Example 2. FIG.
【図７】比較例２の溶銑成分の経時変化を示す図であ
る。FIG. 7 is a view showing a change with time of a hot metal component of Comparative Example 2.
１…酸素ランス、２…耐火物ランス、３…炉体、４…ホ
ッパー、５…溶銑、６…カバースラグ、７…スクラッ
プ、８…酸素ジェット、９…ガス発生物質。1 ... Oxygen lance, 2 ... Refractory lance, 3 ... Furnace body, 4 ... Hopper, 5 ... Hot metal, 6 ... Cover slag, 7 ... Scrap, 8 ... Oxygen jet, 9 ... Gas generating substance.
Claims (1)
度が 3％以上の溶銑状態で配合率15％以下の冷鉄源の完
全溶解と脱 P処理を行うに際し、前半の冷鉄源溶解期に
おいて、鉄浴中に浸漬した耐火物ランスから、キャリア
ガスとフラックスの分解反応により発生する CO2ガス量
の合計が 0.2〜0.5Nm3/min・t の範囲になるようにキャ
リアガスとともに前記フラックスを吹込み、同時に鉄浴
表面に生成するカバースラグの塩基度が 1.5〜2.5 の範
囲になるように調整した脱 Pフラックスを脱Si反応が完
了するまで上方あるいは耐火物ランスから添加し、冷鉄
源溶解完了後の後半の脱 P期において、鉄浴中に浸漬し
た耐火物ランスから、キャリアガスとフラックスの分解
反応により発生する CO2ガス量の合計が 0.05Nm3/min・
t 以下になるようにキャリアガスとともに前記フラック
スを吹込むことを特徴とする予備精錬方法。1. An upper-blown converter-type oxygen refining furnace is used to perform complete melting and de-P treatment of a cold iron source with a C content of 3% or more and a mixture ratio of 15% or less in the first half. During the iron source dissolution period, the carrier so that the total amount of CO 2 gas generated by the decomposition reaction of the carrier gas and flux from the refractory lance immersed in the iron bath is in the range of 0.2 to 0.5 Nm 3 / min ・ t. The above flux is blown together with the gas, and at the same time, the de-P flux adjusted so that the basicity of the cover slag that forms on the iron bath surface is in the range of 1.5 to 2.5 is added from above or from the refractory lance until the de-Si reaction is completed. However, in the latter half P removal period after the completion of melting of the cold iron source, the total amount of CO 2 gas generated by the decomposition reaction of the carrier gas and the flux from the refractory lance immersed in the iron bath was 0.05 Nm 3 / min ・
A pre-refining method, characterized in that the flux is blown together with a carrier gas so as to be t or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3537495A JP3344863B2 (en) | 1995-02-23 | 1995-02-23 | Pre-refining method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3537495A JP3344863B2 (en) | 1995-02-23 | 1995-02-23 | Pre-refining method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08232009A true JPH08232009A (en) | 1996-09-10 |
| JP3344863B2 JP3344863B2 (en) | 2002-11-18 |
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ID=12440133
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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| Country | Link |
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