JP2002047509A - Method for refining molten iron - Google Patents
Method for refining molten ironInfo
- Publication number
- JP2002047509A JP2002047509A JP2000231697A JP2000231697A JP2002047509A JP 2002047509 A JP2002047509 A JP 2002047509A JP 2000231697 A JP2000231697 A JP 2000231697A JP 2000231697 A JP2000231697 A JP 2000231697A JP 2002047509 A JP2002047509 A JP 2002047509A
- Authority
- JP
- Japan
- Prior art keywords
- slag
- hot metal
- molten iron
- desiliconization
- concentration
- 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.)
- Pending
Links
- 0 C*1(C*CC1)S Chemical compound C*1(C*CC1)S 0.000 description 2
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]
【発明の属する技術分野】本発明は、上底吹転炉で脱珪
・脱りん処理を分離して行う溶銑の精錬方法に関し、特
に溶銑脱珪・脱りん処理時に発生するスラグ量を低減で
きる溶銑の精錬方法に関するBACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for refining hot metal by separating desiliconization and dephosphorization in an upper-bottom blower, and in particular, to reduce the amount of slag generated during hot metal desiliconization and dephosphorization. Hot metal refining method
【０００２】[0002]
【従来の技術】近年、鋼の溶製時に発生するスラグに関
わる環境問題の対策として、スラグ発生量の低減が求め
られている。2. Description of the Related Art In recent years, it has been required to reduce the amount of slag generated as a countermeasure against environmental problems related to slag generated when steel is melted.
【０００３】例えば溶銑脱りん処理では、高い脱りん効
率を得るためスラグ塩基度 (Ｃa Ｏ／Ｓi Ｏ2 質量比)
を２〜３以上にする必要がある。そのため、溶銑中の
[Ｓi]濃度が高いときにはＣa Ｏ含有物質の使用量が多
くなりスラグ発生量が増加して環境上問題となる。For example the hot metal dephosphorization treatment, slag basicity to obtain a high dephosphorization efficiency (Ca O / Si O 2 mass ratio)
Needs to be 2-3 or more. Therefore,
When the [Si] concentration is high, the amount of the CaO-containing material used increases, and the amount of slag generated increases, which is an environmental problem.
【０００４】このように溶銑中の [Ｓi]濃度が高いとき
のスラグ発生量増加問題を解決する方法として、高炉の
鋳床樋での脱珪処理や溶銑鍋での脱珪処理が行われてい
る。しかしながら、これらの方法では長時間処理による
耐火物の損耗や熱損失の増大が問題となる。[0004] As a method of solving the problem of increasing the amount of slag generated when the [Si] concentration in the hot metal is high, desiliconization in a cast floor gutter of a blast furnace or desiliconization in a hot metal pot is performed. I have. However, in these methods, there is a problem in that the refractory is worn out and heat loss is increased due to long-term treatment.
【０００５】また、溶銑中の [Ｓi]濃度を例えば０. １
５％以下まで低減する場合、脱珪反応と共に脱炭反応も
進行するためスラグフォーミングやスロッピングが顕著
になり、上記反応容器ではフリーボードが小さいため、
操業が困難になるという問題がある。[0005] Further, the [Si] concentration in the hot metal is set to, for example, 0.1.
When it is reduced to 5% or less, the decarburization reaction proceeds together with the desiliconization reaction, so that slag forming and sloping become remarkable.
There is a problem that operation becomes difficult.
【０００６】上記問題を解決する方法として、例えば特
開平５−９５３３号公報には、転炉型の処理容器中の溶
銑に造塊スラグを主成分とする造滓剤を添加して脱珪す
る方法が示されている。As a method for solving the above-mentioned problem, for example, Japanese Patent Laid-Open Publication No. HEI 5-9533 discloses a method of adding a slag-forming agent mainly composed of ingot slag to hot metal in a converter type processing vessel to remove silicon. The method is shown.
【０００７】しかしながら、造塊スラグ中には約１０％
以上のＡl2Ｏ3 が含有されており、転炉吹錬時にスラグ
フォーミングやスロッピングを誘発し操業が安定しない
おそれがある。[0007] However, about 10%
Since Al 2 O 3 as described above is contained, slag forming and slopping are induced during converter blowing, and the operation may not be stable.
【０００８】また、脱珪スラグを効率良く排出しなけれ
ば、脱りんスラグ発生量を低減することが困難となる
が、特開平５−９５３３合公報には、その効率的な方法
について詳細な記述がない。Further, it is difficult to reduce the amount of dephosphorized slag unless the desiliconized slag is efficiently discharged. Japanese Patent Application Laid-Open No. Hei 5-9533 describes in detail the efficient method. There is no.
【０００９】更に、転炉で溶銑脱りん処理する場合、溶
銑中の［Ｓi］濃度が低すぎると、生石灰等の脱りん剤
が十分に溶融しきれず、その結果、脱りん反応効率が低
下することは広く知られている。Further, in the case of hot metal dephosphorization in a converter, if the [Si] concentration in the hot metal is too low, the dephosphorizing agent such as quick lime cannot be melted sufficiently, and as a result, the dephosphorization reaction efficiency decreases. It is widely known.
【００１０】この改善策としては、蛍石を添加すること
により、スラグの融点を下げて脱りん反応を促進する方
法が一般的であるが、この方法では耐火物溶損量が増加
するという問題がある。As a remedy, a method of adding a fluorite to lower the melting point of the slag to promote the dephosphorization reaction is generally used. However, this method has a problem that the amount of erosion of the refractory increases. There is.
【００１１】その解決策として、特開平８−３１１５２
３号公報には、Ｃa Ｏ粉を上吹酸素と共に溶銑に吹き付
けて脱りんする方法の提案が開示されている。As a solution, Japanese Patent Laid-Open Publication No. Hei 8-31152
No. 3 discloses a proposal for a method of dephosphorizing by blowing CaO powder onto hot metal together with top-blown oxygen.
【００１２】[0012]
【発明が解決しようとする課題】しかし、上吹酸素流量
が溶銑質量トン当たり２m3 (標準状態)/min 以下となる
と、溶銑中の [Ｓi]濃度が０．１〜０．３％の間で溶銑
中の [Ｓi]濃度が低いほど脱りん剤の溶融性が悪化する
おそれがある。However, when the flow rate of the top-blown oxygen is 2 m 3 (standard state) / min or less per ton of hot metal, the [Si] concentration in the hot metal is 0.1 to 0.3%. As the [Si] concentration in the hot metal is lower, the melting property of the dephosphorizing agent may deteriorate.
【００１３】本発明の目的は、（１）溶銑中の [Ｓi]濃
度を０. １％以下にまで迅速に低減し、（２）脱珪スラ
グを溶融状態にして、効率良く炉口から排出し、（３）
溶銑中の [Ｓi]濃度が０．１％以下のレベルでも脱りん
剤の溶融性を維持でき、高脱りん率が得られ、（４）し
かも溶銑脱珪・脱りん処理時に発生するスラグ量を低減
できる溶銑の精錬方法を提供することにある。It is an object of the present invention to (1) rapidly reduce the [Si] concentration in hot metal to 0.1% or less, and (2) put desiliconized slag in a molten state and efficiently discharge it from a furnace port. And (3)
Even if the [Si] concentration in the hot metal is at a level of 0.1% or less, the dephosphorizing agent can maintain the melting property and a high dephosphorization rate can be obtained. (4) In addition, the amount of slag generated during hot metal desiliconization and dephosphorization treatment It is an object of the present invention to provide a hot metal refining method capable of reducing the amount of hot metal.
【００１４】[0014]
【課題を解決するための手段】本発明者は、溶銑中の
[Ｓi]濃度が０．１％以下のレベルでも脱りん剤の溶融
性を維持でき、高脱りん率が得られる方法について検討
した結果、下記の知見を得た。Means for Solving the Problems The inventor of the present invention has developed
The following findings were obtained as a result of examining a method for maintaining the melting property of the dephosphorizing agent even at a [Si] concentration of 0.1% or less and obtaining a high dephosphorization rate.
【００１５】（Ａ）上底吹転炉形式の炉に溶銑を装入し
て、脱炭スラグ (脱炭スラグとは脱りん溶銑を脱炭した
際に生成するスラグ) と必要に応じて酸化鉄を溶銑に上
置き添加した後、上吹ランスから溶銑１質量トン当たり
１. ０〜２．５m3 (標準状態)/min の酸素を溶銑に吹き
付けながら、底吹羽口から溶銑１質量トン当たり０.０
５〜０. ６０m3 (標準状態)/min の攪拌用ガスを吹き込
むことにより、溶銑中の [Ｓi]濃度を０. １０％以下ま
で迅速に低減することができる。(A) Hot metal is charged into an upper-bottom blower type furnace, and decarburized slag (decarburized slag is slag generated when dephosphorized hot metal is decarburized) and optionally oxidized. After the iron is placed on the hot metal and added, the top blowing lance blows oxygen at a rate of 1.0 to 2.5 m 3 (standard state) / min per 1 ton of hot metal, 0.0 per
By blowing a stirring gas at 5 to 0.60 m 3 (standard state) / min, the [Si] concentration in the hot metal can be rapidly reduced to 0.10% or less.
【００１６】なお、脱炭スラグの使用は、以下のメリッ
トがある。 ・脱炭スラグは、一旦溶融したものであるため極めて速
やかに再溶融し易い。 ・脱炭スラグは、造塊スラグと異なりＡl2Ｏ3 含有量が
約１％と低いので、脱珪処理中にスロッピング等を生じ
難い。 ・脱炭スラグ中にはＣａＯが既に含有されており、新た
に生石灰等を添加する必要が無いため、スラグを生成す
るためのコストを低減できる。The use of decarburized slag has the following advantages. -Since the decarburized slag is once melted, it is easily remelted very quickly. - decarburization slag, since about 1% and less content of Al 2 O 3 different from an ingot-making slag, hardly occurs slopping or the like during desiliconization treatment. -CaO is already contained in the decarburized slag, and it is not necessary to newly add quicklime or the like, so that the cost for generating the slag can be reduced.
【００１７】（Ｂ）脱珪スラグを効率良く炉口から排出
するには、スラグの流動性を良好にすることが重要であ
り、粒径３〜３０mmの脱炭スラグを使用して脱珪スラグ
の塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）を０. ４〜１. ２
に調整するとよい。(B) In order to efficiently discharge the desiliconized slag from the furnace port, it is important to improve the fluidity of the slag, and the desiliconized slag having a particle size of 3 to 30 mm is used. 4-1 of basicity (Ca O / Si O 2 mass ratio) 0.5. 2
It is good to adjust.
【００１８】（Ｃ）脱珪スラグを排出後、上吹ランスか
らＣa Ｏ含有粉を、溶銑１質量トン当たり０. ５〜２．
５m3 (標準状態)/min の酸素をキャリアーガスとして吹
き付けながら、底吹羽口から溶銑１質量トン当たり０.
０５〜０. ６０m3 (標準状態)/min の攪拌用ガスを吹き
こむことにより脱りんスラグを高塩基度に維持しながら
溶融性を良好にすることができ、脱りん率を高くするこ
とが可能となる。(C) After the desiliconized slag is discharged, the CaO-containing powder is supplied from the upper blowing lance to 0.5 to 2.
While spraying 5 m 3 (standard condition) / min of oxygen as a carrier gas, the bottom blown tuyere has a flow rate of 0.
By blowing a stirring gas at a rate of 0.5 to 0.60 m 3 (standard state) / min, the dephosphorization slag can be maintained at a high basicity and the meltability can be improved, and the dephosphorization rate can be increased. It becomes possible.
【００１９】なお、攪拌用ガスとしては、Ａr 、Ｃ
Ｏ2 、Ｎ2 等が使用できる。 （Ｄ）Ｃa Ｏ含有粉に、Ａl2Ｏ3 およびＦe2Ｏ3 の少な
くとも一種以上を混合した粉を上吹酸素と共に溶銑に吹
き付けて脱りんすることにより、さらに脱りん率を向上
できる。The stirring gas is Ar, C or the like.
O 2 and N 2 can be used. (D) A powder in which at least one of Al 2 O 3 and Fe 2 O 3 is mixed with the CaO-containing powder is blown onto hot metal together with the upper blowing oxygen to remove phosphorus, thereby further improving the phosphorus removal rate.
【００２０】（Ｅ）以上の（Ａ）〜（Ｄ）の知見を基に
脱珪処理と脱りん処理とを分離して行うと、脱珪・脱り
ん処理を同時に行うときに比べて大幅にスラグ量を低減
できる。(E) When the desiliconization treatment and the dephosphorization treatment are performed separately based on the findings of (A) to (D) above, the desiliconization treatment and the dephosphorization treatment are significantly performed as compared with the case where the desiliconization treatment and the dephosphorization treatment are performed simultaneously. The amount of slag can be reduced.
【００２１】本発明は、以上の知見に基づいてなされた
もので、その要旨は、下記のとおりである。 （１）上底吹転炉に溶銑を装入して脱珪・脱りん処理を
行う溶銑の精錬方法において、（ａ）粒径が３〜３０mm
の脱炭スラグを溶銑に上置きした後、（ｂ）上吹ランス
から酸素を溶銑１質量トン当たり１. ０〜２．５m3 (標
準状態)/min 吹き付けながら、底吹羽口から溶銑１質量
トン当たり０. ０５〜０. ６０m3 (標準状態)/min の攪
拌用ガスを吹き込むことにより脱珪処理を行い、（ｃ）
溶銑中の [Ｓi]濃度を０. １０％以下、脱珪スラグの塩
基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）を０. ４〜１. ２とし
た後、（ｄ）炉内に生成した脱珪スラグを上底吹転炉の
傾動により炉口から排出し、（ｅ）脱珪スラグが排出さ
れた脱珪溶銑に上吹ランスからＣａＯ含有粉を、溶銑１
質量トン当たり０. ５〜２．５m3 (標準状態)/min の酸
素をキャリアーガスとして吹き付けながら、底吹羽口か
ら溶銑１質量トン当たり０. ０５〜０. ６０m3 (標準状
態)/minの攪拌用ガスを吹き込むことにより脱りん処理
を行うことを特徴とする溶銑の精錬方法。 （２）前記Ｃa Ｏ含有粉は、Ａl2Ｏ3 およびＦe2Ｏ3 の
少なくとも一種を含有することを特徴とする上記（１）
に記載の溶銑の精錬方法。The present invention has been made based on the above findings, and the gist thereof is as follows. (1) In a method of refining hot metal in which hot metal is charged into an upper-bottom blower and desiliconized and dephosphorized, (a) a particle size of 3 to 30 mm
After the decarburized slag was placed on the hot metal, (b) oxygen was blown from the bottom blowing tuyere through the upper blowing lance at a rate of 1.0 to 2.5 m 3 (standard condition) / min per 1 ton of hot metal. A desiliconization treatment is performed by blowing a stirring gas at a rate of 0.05 to 0.60 m 3 (standard state) / min per mass ton, and (c)
The molten iron [Si] concentration 0.10% or less, after the basicity of the desiliconization slag (Ca O / Si O 2 mass ratio) was from 0.4 to 1.2, produced in (d) of furnace The desiliconized slag is discharged from the furnace port by tilting the upper and lower blown converter, and (e) the CaO-containing powder is supplied from the upper blowing lance to the desiliconized hot metal from which the desiliconized slag has been discharged.
While blowing oxygen mass per tonne 0. 5~2.5m 3 (standard state) / min as a carrier gas, the bottom吹羽port from hot metal 1 mass ton 0. 05~0. 60m 3 (standard state) / min A method for refining hot metal, comprising performing a dephosphorization treatment by blowing a stirring gas. (2) the Ca O-containing powder, the (1), characterized in that it contains at least one of Al 2 O 3 and Fe 2 O 3
The method for refining hot metal according to item 1.
【００２２】[0022]
【発明の実施の形態】図１（ａ）、（ｂ）および（ｃ）
は、本発明の精錬方法を順に模式的に示す概念図であ
り、図１（ａ）は上底吹転炉で溶銑脱珪する工程を、図
１（ｂ）は上底吹転炉を傾動して脱珪スラグを排出する
工程を、図１（ｃ）は上底吹転炉で溶銑脱りんする工程
をそれぞれ示す。1 (a), 1 (b) and 1 (c).
FIGS. 1A and 1B are conceptual diagrams schematically illustrating a refining method of the present invention in order. FIG. 1A shows a process of desiliconizing hot metal in an upper-bottom blow converter, and FIG. FIG. 1 (c) shows the step of dephosphorizing hot metal in an upper-bottom blower, respectively.
【００２３】なお、図中の符号は、上底吹転炉１、上吹
ランス２、底吹羽口３、脱珪溶銑４、脱珪スラグ５、脱
りんスラグ６および脱りん溶銑７である。同図に示すよ
うに、本発明は上底吹転炉１に溶銑４を装入して所定の
濃度まで溶銑脱珪する工程（ａ）、次に炉体を傾動し
て、脱珪スラグ５を可能な限り炉外へ排出する工程
（ｂ）、そして炉体を直立状態に戻してから、上吹ラン
ス２から上吹酸素と共にＣa Ｏ含有粉を溶銑に吹き付け
て脱りんする工程（ｃ）からなる。Reference numerals in the figure are an upper-bottom blowing converter 1, an upper blowing lance 2, a bottom blowing tuyere 3, a desiliconized hot metal 4, a desiliconized slag 5, a dephosphorized slag 6, and a dephosphorized hot metal 7. . As shown in the figure, the present invention comprises a step (a) of charging hot metal 4 into an upper-bottom blowing converter 1 and desiliconizing hot metal to a predetermined concentration, and then tilting the furnace body to remove desiliconized slag 5. (B) to remove as much as possible out of the furnace, and after returning the furnace body to the upright state, degassing by blowing the CaO-containing powder together with the oxygen from the upper blowing lance 2 onto the molten iron (c). Consists of
【００２４】溶銑中の [Ｓi]濃度を０. １０％以下にま
で効率よく低減するには、上底吹転炉１を用いるが、上
底吹転炉を用いる理由は、以下の（１）〜（３）に記載
の通りである。In order to efficiently reduce the [Si] concentration in the hot metal to 0.10% or less, the upper-bottom blowing converter 1 is used. The reason for using the upper-bottom blowing converter is as follows (1). To (3).
【００２５】（１）高炉鋳床や鍋で脱珪する際に通常脱
珪剤として酸化鉄を用いるが、本来冷却剤である酸化鉄
を添加するため処理中の温度低下が著しく、その温度低
下を抑制するため気体酸素も併用する。しかし、気体酸
素をあまり多く使うと、酸化鉄を主成分とするダストが
多量に発生し、作業環境が著しく悪化するという問題が
発生する。(1) Usually, iron oxide is used as a desiliconizing agent when desiliconizing in a blast furnace cast floor or a pan. However, since iron oxide, which is originally a cooling agent, is added, the temperature during the treatment significantly decreases. Gaseous oxygen is also used for suppression. However, if too much gaseous oxygen is used, a large amount of dust containing iron oxide as a main component is generated, causing a problem that the working environment is significantly deteriorated.
【００２６】（２）溶銑中の [Ｓi]濃度を０. １０％以
下にまで低減すると、脱炭反応が並行して生じるため、
スラグのフォーミング量も多くなる。このフォーミング
によってスラグが反応容器から溢れ出るおそれがある。(2) If the [Si] concentration in the hot metal is reduced to 0.10% or less, the decarburization reaction occurs in parallel,
The amount of slag forming also increases. This forming may cause slag to overflow from the reaction vessel.
【００２７】（３）このようなダストの発生やスラグの
フォーミングの問題を回避するにはかなり大きなフリー
ボードがある上底吹転炉の使用が有効である。すなわ
ち、上底吹転炉であれば、酸化鉄を多量に添加できるの
はもちろん、上吹ランスから多量の気体酸素を溶銑に吹
き付けられ、しかも強力な底吹ガス攪拌により非常に迅
速に脱珪処理できる。(3) In order to avoid such problems of dust generation and slag forming, it is effective to use an upper-bottom blowing converter having a considerably large free board. In other words, top-bottom blow converters can not only add a large amount of iron oxide, but also blow a large amount of gaseous oxygen to the hot metal from the top-blowing lance, and very quickly desiliconize with strong bottom-blown gas agitation. Can be processed.
【００２８】但し、脱珪処理後の溶銑中の [Ｓi]濃度は
０. ０３％以上とするのが望ましい。それは、 [Ｓi]濃
度が０. ０３％以下になると脱炭反応の方が優勢になっ
て脱珪速度が急激に低下するおそれがあるからである。However, it is desirable that the [Si] concentration in the hot metal after the desiliconization treatment is 0.03% or more. This is because, when the [Si] concentration is less than 0.03%, the decarburization reaction becomes more dominant, and the desiliconization rate may decrease rapidly.
【００２９】次に脱珪処理のときの上底吹転炉における
上底吹条件について述べる。以下に示すグラフは、全て
２質量トン容量の試験用上底吹転炉を使用して行った試
験結果を示す。Next, the conditions of the top and bottom blowing in the top and bottom blowing converter during the desiliconization treatment will be described. The graphs shown below show the results of tests performed using a test top-bottom blower having a capacity of 2 mass tons.
【００３０】図２は、溶銑１質量トン当たり上吹酸素流
量と、脱珪処理後の溶銑中の [Ｓi]濃度およびスピッテ
ィング指数との関係を示すグラフである。なお、このグ
ラフは底吹Ａｒ流量が溶銑１質量トン当たり０. ２m3
(標準状態)/min 一定で上吹酸素と同様に約３分間溶銑
に吹き込み、かつ脱珪処理前の溶銑中の [Ｓi]濃度が約
０. ３％一定下での試験結果を示す。FIG. 2 is a graph showing the relationship between the top blowing oxygen flow rate per 1 ton of hot metal, the [Si] concentration in the hot metal after the desiliconization treatment, and the spitting index. This graph shows that the flow rate of bottom blown Ar is 0.2 m 3 per 1 ton of hot metal.
(Standard condition) / min The test results are shown in which the molten iron is blown into the hot metal for about 3 minutes in the same manner as the top-blown oxygen and the [Si] concentration in the hot metal before the desiliconization treatment is constant at about 0.3%.
【００３１】また、スピッティング指数とは、上吹酸素
流量を溶銑１質量トン当たり１. ０m3 (標準状態)/min
としたときのスピッティング量を基準に指数化したもの
である。The spitting index is defined as the flow rate of the upwardly blown oxygen being 1.0 m 3 (standard state) / min per 1 ton of hot metal.
Is an index based on the amount of spitting when.
【００３２】同図に示すように、溶銑１質量トン当たり
上吹酸素流量が１．０m3 (標準状態)/min 未満では脱珪
処理後の溶銑中の [Ｓi]濃度が０. １％を超え、溶銑１
質量トン当たり上吹酸素流量が２．５m3 (標準状態)/mi
n を超えるとスピッティング指数が急激に上昇する。As shown in the figure, when the flow rate of the top blowing oxygen per 1 ton of hot metal is less than 1.0 m 3 (standard condition) / min, the [Si] concentration in the hot metal after the desiliconization treatment is 0.1%. Exceeded, hot metal 1
2.5m 3 (standard condition) / mi
Above n, the spitting index rises sharply.
【００３３】図３は、溶銑１質量トン当たり底吹Ａｒ流
量と、脱珪処理後の溶銑中の [Ｓi]濃度およびスピッテ
ィング指数との関係を示すグラフである。なお、このグ
ラフは上吹酸素流量が溶銑１質量トン当たり１. ０m3
(標準状態)/min 一定で底吹Ａｒと同様に約３分間溶銑
に吹き付け、かつ脱珪処理前の溶銑中の [Ｓi]濃度が約
０. ３％一定下での試験結果を示す。FIG. 3 is a graph showing the relationship between the flow rate of bottom blown Ar per 1 ton of hot metal, the [Si] concentration in the hot metal after the desiliconization treatment, and the spitting index. In addition, this graph shows that the flow rate of the top blowing oxygen is 1.0 m 3 per 1 ton of hot metal.
(Standard condition) The test results are shown in which the molten iron is sprayed on the molten iron at a constant rate of / min for about 3 minutes in the same manner as the bottom blown Ar, and the [Si] concentration in the molten iron before the desiliconization treatment is constant at about 0.3%.
【００３４】また、スピッティング指数とは、底吹Ａｒ
流量を０．０５m3 (標準状態)/minとしたときのスピッ
ティング量を基準に指数化したものである。同図に示す
ように、溶銑１質量トン当たり底吹Ａｒ流量が０．０５
m3 (標準状態)/min 未満では脱珪処理後の溶銑中の [Ｓ
i]濃度が０. １％を超え、溶銑１質量トン当たり底吹Ａ
ｒ流量が０．６m3 (標準状態)/min を超えるとスピッテ
ィング指数が急激に上昇する。Further, the spitting index is the bottom blowing Ar
The index is based on the amount of spitting when the flow rate is 0.05 m 3 (standard state) / min. As shown in FIG.
If m 3 (standard state) / min is less than [S
i] When the concentration exceeds 0.1%, bottom blow A per 1 ton of hot metal
When the flow rate exceeds 0.6 m 3 (standard condition) / min, the spitting index rises sharply.
【００３５】次に、炉体を傾動して脱珪スラグを炉外へ
排出するのであるが、スラグの性状とスラグ排出率との
関係を調査した。図４は脱珪時に添加するＣa Ｏ含有物
質の性状をパラメータとしたスラグ塩基度とスラグ排出
率との関係を示すグラフである。Next, the furnace body was tilted to discharge the desiliconized slag out of the furnace, and the relationship between the properties of the slag and the slag discharge rate was investigated. FIG. 4 is a graph showing the relationship between the slag basicity and the slag discharge rate using the properties of the CaO-containing substance added during desiliconization as a parameter.
【００３６】なお、スラグ排出率は排出スラグの秤量値
と、物質収支で計算した生成スラグ量との比（排出スラ
グの秤量値（ｋｇ）／生成スラグ量の計算値（ｋｇ））
を％表示して求めた。The slag discharge ratio is the ratio of the weighed value of the discharged slag to the amount of generated slag calculated by the material balance (weighed value of discharged slag (kg) / calculated value of generated slag (kg)).
Was expressed in%.
【００３７】また、表１に使用した脱炭スラグの代表的
な組成を示す。Table 1 shows a typical composition of the decarburized slag used.
【００３８】[0038]
【表１】 同図に示すように、粒径を３〜３０mmとした脱炭スラグ
（●）によりスラグ塩基度を０. ４〜１. ２とすること
でスラグの流動性を確保でき約８０％という高いスラグ
排出率が得られる。[Table 1] As shown in the figure, a decarburized slag (●) having a particle size of 3 to 30 mm and a slag basicity of 0.4 to 1.2 can secure the fluidity of the slag, and a high slag of about 80% can be obtained. The emission rate is obtained.
【００３９】一方、ほぼ同じ粒径の生石灰（○）ではス
ラグ排出率が約７０％であり、粒径を３５〜４５mmとし
た脱炭スラグ（△）でも約７０％と低い値である。脱炭
スラグが生石灰に比べて良好な理由は、脱炭スラグは一
旦溶融されたものなので生石灰に比べ融点が低く溶融し
易いからである。On the other hand, quicklime (○) having almost the same particle size has a slag discharge rate of about 70%, and decarburized slag (△) having a particle size of 35 to 45 mm has a low value of about 70%. The reason why the decarburized slag is better than quick lime is that the decarburized slag has a lower melting point than quick lime and is easily melted since it has been once melted.
【００４０】また、同じ脱炭スラグでも数分以内という
迅速脱珪処理時間中に完全に溶融させるには、粒径を３
０mm以下にまで細かくすることが必須となることも判明
した。In order to completely melt the same decarburized slag during the rapid desiliconization time of several minutes or less, the particle size must be 3 μm.
It has also been found that it is essential to make the size smaller than 0 mm.
【００４１】さらに、粒径が３mm未満となると炉内へ装
入する際に排ガス集塵機へ吸引されてしまい、歩留まり
が悪化し、所定のスラグ組成を実現できなくなる。以上
から、粒径が３〜３０mmの脱炭スラグを用いるのが有効
である。Further, when the particle size is less than 3 mm, the powder is sucked into the exhaust gas precipitator when charged into the furnace, the yield is deteriorated, and a predetermined slag composition cannot be realized. From the above, it is effective to use decarburized slag having a particle size of 3 to 30 mm.
【００４２】次に、スラグが約８０％排出され、溶銑中
の [Ｓi]濃度が０. １０％以下となった溶銑を脱りんす
る方法について述べる。図５は脱りん剤の添加方法をパ
ラメータとした溶銑中の [Ｓi]濃度と脱りん率との関係
を示すグラフである。Next, a method for dephosphorizing hot metal from which slag has been discharged by about 80% and the [Si] concentration in the hot metal has become 0.10% or less will be described. FIG. 5 is a graph showing the relationship between the [Si] concentration in the hot metal and the dephosphorization rate using the method of adding the dephosphorizer as a parameter.
【００４３】なお、溶銑は２質量トンで、上底吹は一定
条件（上吹酸素流量：３m3 (標準状態)/min 、底吹Ａr
流量：０. ８m3 (標準状態)/min)で４分間行い、脱りん
剤の添加方法は以下の通りある。The hot metal is 2 mass tons, the top and bottom blows are under constant conditions (top blown oxygen flow rate: 3 m 3 (standard state) / min, bottom blown Ar
Flow rate: 0.8 m 3 (standard condition) / min) for 4 minutes, and the method of adding the dephosphorizing agent is as follows.
【００４４】○：鉄鉱石２０ｋｇおよび粒状Ｃa Ｏ１５
ｋｇを溶銑に上置きした後、上底吹を行った。 ●：鉄鉱石２０ｋｇを溶銑に上置きし、上吹酸素をキャ
リアーガスとしてＣaＯ粉１５ｋｇを溶銑に吹き付け
た。Ｃa Ｏ粉としては、純度９８％ (粉径０. ０１〜
０. １５ｍｍ) を使用した。○: 20 kg of iron ore and granular CaO15
After placing the kg on the hot metal, top and bottom blowing was performed. ●: 20 kg of iron ore was placed on the hot metal, and 15 kg of CaO powder was sprayed on the hot metal using the upper blowing oxygen as a carrier gas. 98% purity as CaO powder (powder diameter 0.01 ~
0.15 mm) was used.
【００４５】▲：鉄鉱石２０ｋｇを溶銑に上置きし、上
吹酸素をキャリアーガスとして（Ｃa Ｏ＋Ａl2Ｏ3)粉１
５ｋｇを溶銑に吹き付けた。Ａl2Ｏ3 粉としては、純度
９８％ (粉径０. ０１〜０. １５ｍｍ) を使用し、Ｃa
Ｏ粉量に対して２０質量％混合した。▲: 20 kg of iron ore was placed on hot metal, and (CaO + Al 2 O 3 ) powder 1
5 kg was sprayed on the hot metal. As Al 2 O 3 powder, a purity of 98% (powder diameter: 0.01 to 0.15 mm) is used.
20 mass% was mixed with respect to the amount of O powder.
【００４６】□：鉄鉱石２０ｋｇを溶銑に上置きし、上
吹酸素をキャリアーガスとして（Ｃa Ｏ＋Ｆe2Ｏ3)粉１
５ｋｇを溶銑に吹き付けた。Ｆe2Ｏ3 粉としては、純度
９８％ (粉径０. ０１〜０. １５ｍｍ) を使用し、Ｃa
Ｏ粉量に対して２０質量％混合した。□: 20 kg of iron ore is placed on hot metal, and (CaO + Fe 2 O 3 ) powder 1
5 kg was sprayed on the hot metal. As the Fe 2 O 3 powder, a purity of 98% (powder diameter: 0.01 to 0.15 mm) is used.
20 mass% was mixed with respect to the amount of O powder.
【００４７】同図に結果を示すように、粒状Ｃa Ｏを上
置きした○印の方法は溶銑中の [Ｓi]濃度の低下ととも
に脱りん率が低下するが、上吹酸素をキャリアーガスと
してＣa Ｏ粉を吹き付けた●印の方法は脱りん率が８５
％以上と高く、特に溶銑中の[Ｓi]濃度が０．１％以下
で約９０％と脱りん率が高くなる。As shown in the figure, the method indicated by a circle in which granular CaO is placed on the top decreases the dephosphorization rate as the [Si] concentration in the hot metal decreases. The method indicated by the ● mark sprayed with O powder has a dephosphorization rate of 85.
%, Especially when the [Si] concentration in the hot metal is 0.1% or less, the dephosphorization rate becomes high at about 90%.
【００４８】また、▲および□印の方法は溶銑中の [Ｓ
i]濃度が０．１％で約９５％と極めて高い脱りん率が得
られる。上吹酸素と共に溶銑に吹き付けるＣa Ｏ含有粉
に、Ａl2Ｏ3 含有粉およびＦe2Ｏ3 含有粉の混合により
脱りん率が向上した理由としては、Ａl2Ｏ3 やＦe2Ｏ3
がＣa Ｏの溶融促進剤として作用したからと推定でき
る。The methods marked with ▲ and □ indicate that [S
i] At a concentration of 0.1%, an extremely high dephosphorization rate of about 95% can be obtained. The reason why the dephosphorization rate was improved by mixing the Al 2 O 3 -containing powder and the Fe 2 O 3 -containing powder with the CaO-containing powder sprayed onto the hot metal together with the upper blowing oxygen is that Al 2 O 3 or Fe 2 O 3
Can act as a CaO melting accelerator.
【００４９】図６は上吹酸素流量と脱りん率との関係を
示すグラフである。なお、試験方法は下記の通りであ
る。溶銑が２質量トンで、溶銑中の [Ｓi]濃度を約０．
１％に脱珪処理した後、塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量
比）が０. ５の脱珪スラグを約８０％排出した。FIG. 6 is a graph showing the relationship between the flow rate of oxygen blown upward and the dephosphorization rate. The test method is as follows. The hot metal is 2 mass tons, and the [Si] concentration in the hot metal is about 0.
After desiliconization processed 1%, basicity (Ca O / Si O 2 mass ratio) is discharged to about 80% desiliconization slag 0.5.
【００５０】鉄鉱石２０ｋｇを溶銑に上置きし、底吹羽
口からＡr を０. ８m3 (標準状態)/min で溶銑へ約４分
間吹き込みつつ、キャリアーガスの上吹酸素流量を変更
してＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けた。20 kg of iron ore is placed on the hot metal, and Ar is blown into the hot metal at a rate of 0.8 m 3 (standard condition) / min from the bottom blowing port for about 4 minutes, while changing the upper flow oxygen flow rate of the carrier gas. 15 kg of CaO powder was sprayed on the hot metal in about 4 minutes.
【００５１】図６に示すように、０. ５m3 (標準状態)/
min 以上で脱りん率が８５％以上と高くなる。０. ５m3
(標準状態)/min未満では、上吹酸素と溶銑中鉄分との
反応により生成するＦe Ｏ量が少ないため、スラグ中の
(Ｆe Ｏ) 濃度を高く維持できなくなり、脱りん率が低
下するものと推定できる。As shown in FIG. 6, 0.5 m 3 (standard condition) /
At min or more, the dephosphorization rate becomes high at 85% or more. 0. 5m 3
At less than (standard state) / min, the amount of FeO generated by the reaction between the top-blown oxygen and the iron in the hot metal is small.
It can be estimated that the (FeO) concentration cannot be maintained at a high level and the dephosphorization rate decreases.
【００５２】図７は上吹酸素流量とスピッティング指数
との関係を示すグラフである。なお、試験方法は下記の
通りである。溶銑中の [Ｓi]濃度を約０．１％に脱珪処
理した後、塩基度（Ｃa Ｏ／Ｓi Ｏ 2 質量比）が０. ５
の脱珪スラグを約８０％排出した。FIG. 7 shows the top blowing oxygen flow rate and the spitting index.
6 is a graph showing a relationship with the graph. The test method is as follows
It is on the street. Desiliconization to reduce [Si] concentration in hot metal to about 0.1%
After processing, the basicity (CaO / SiO2) TwoMass ratio) is 0.5
About 80% of the desiliconized slag was discharged.
【００５３】鉄鉱石２０ｋｇを溶銑に上置きし、底吹羽
口からＡr を０. ８m3 (標準状態)/min で溶銑へ約４分
間吹き込みつつ、キャリアーガスの上吹酸素流量を変更
してＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けた。20 kg of iron ore is placed on the hot metal, and Ar is blown into the hot metal at a rate of 0.8 m 3 (standard condition) / min for about 4 minutes from the bottom blowing tuyere, while changing the upper flow oxygen flow rate of the carrier gas. 15 kg of CaO powder was sprayed on the hot metal in about 4 minutes.
【００５４】また、スピッティング指数とは、上吹酸素
流量を溶銑１質量トン当たり１. ０m3 (標準状態)/min
としたときのスピッティング量を基準に指数化したもの
である。The spitting index is defined as the flow rate of the top blowing oxygen being 1.0 m 3 (standard state) / min per 1 ton of hot metal.
Is an index based on the amount of spitting when.
【００５５】図７に示すように、２．５m3 (標準状態)/
min を超えるとスピッティング指数が急激に高くなる。
従って上吹酸素流量の上限は２．５m3 (標準状態)/min
とした。As shown in FIG. 7, 2.5 m 3 (standard condition) /
Above min, the spitting index rises sharply.
Therefore, the upper limit of the upper oxygen flow rate is 2.5 m 3 (standard condition) / min
And
【００５６】図６および図７から上吹酸素流量は０．５
〜２．５m3 (標準状態)/min がよい。図８は溶銑１質量
トン当たりの底吹Ａr 流量と脱りん率との関係を示すグ
ラフである。From FIGS. 6 and 7, the upper oxygen flow rate is 0.5
~ 2.5m 3 (standard condition) / min is good. FIG. 8 is a graph showing the relationship between the bottom blown Ar flow rate per 1 ton of hot metal and the dephosphorization rate.
【００５７】なお、試験方法は下記の通りである。溶銑
は２質量トンで、溶銑中の [Ｓi]濃度を約０．１％に脱
珪処理した後、塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）が
０. ５の脱珪スラグを約８０％排出した。The test method is as follows. Molten iron is 2 mass ton, after desiliconization treatment [Si] concentration of about 0.1% in the hot metal, the desiliconization slag basicity (Ca O / Si O 2 mass ratio) is 0.5 to about 80 % Discharged.
【００５８】鉄鉱石２０ｋｇを溶銑に上置きし、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けながら
底吹Ａr 流量を変更して脱りん処理を行った。20 kg of iron ore is placed on hot metal, and 15 kg of CaO powder is blown onto the hot metal in about 4 minutes using top-blown oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas, and bottom blown Ar flow rate is adjusted. Modified and dephosphorized.
【００５９】図８に示すように、溶銑１質量トン当たり
の０. ０５m3 (標準状態)/min 以上で脱りん率が８５％
以上と高くなり、０. ６m3 (標準状態)/min を超えると
脱りん率が急激に低下した。As shown in FIG. 8, the dephosphorization rate is 85% at 0.05 m 3 (standard state) / min or more per 1 ton of hot metal.
The dephosphorization rate sharply decreased when it exceeded 0.6 m 3 (standard state) / min.
【００６０】底吹Ａｒ流量が０. ０５m3 (標準状態)/mi
n 未満だと、スラグと溶銑の攪拌・混合が不十分とな
り、スラグ中Ｆe Ｏの溶銑への移動速度の低下し、脱り
ん速度が低下すると推定できる。The bottom blow Ar flow rate is 0.05 m 3 (standard condition) / mi
If it is less than n, it can be estimated that the stirring and mixing of the slag and the hot metal become insufficient, the movement speed of FeO in the slag to the hot metal decreases, and the dephosphorization speed decreases.
【００６１】一方、０. ６m3 (標準状態)/min を超える
と、スラグ中の（Ｆe Ｏ）と溶銑中の [Ｃ] との反応速
度が大きくなり過ぎて、スラグ中の (Ｆe Ｏ) 濃度を高
く維持できないためと推定できる。On the other hand, if it exceeds 0.6 m 3 (standard state) / min, the reaction rate between (FeO) in the slag and [C] in the hot metal becomes too high, and the (FeO) in the slag becomes too high. It can be estimated that the concentration cannot be maintained high.
【００６２】[0062]
【実施例】２質量トン容量の試験用上底吹転炉を用いて
試験を実施した。使用した溶銑は、 [Ｃ] ：約４. ４
％、 [Ｓi]：約０. ４％、 [Ｐ] ：約０.１％、 [Ｍ
n]：約０. ３％を含有するもので、この溶銑を試験用上
底吹転炉に装入し、上吹酸素流量を３〜３．６m3 (標準
状態)/min とし、底吹羽口からのＡr流量を０. ４m3
(標準状態)/min 一定として以下の本発明例および比較
例を行った。EXAMPLES The tests were carried out using a 2 ton-ton capacity test top and bottom blower converter. The hot metal used was [C]: about 4.4
%, [Si]: about 0.4%, [P]: about 0.1%, [M
n]: containing about 0.3%. This hot metal was charged into a test top-bottom blow converter, the top blown oxygen flow rate was 3 to 3.6 m3 (standard condition) / min, and the bottom blown Ar flow rate from tuyere is 0.4m 3
(Standard condition) / min The following examples of the present invention and comparative examples were carried out under a constant condition.
【００６３】また、試験に使用した脱炭スラグの組成は
前記の表１に示した通りである。 （従来例）処理前に３〜３０mm径の脱炭スラグを溶銑１
質量トン当たり約１０kgを上置きし、上吹ランスから
３. ６ｍ3(標準状態)/min の酸素流量で約２分間吹き付
け脱珪処理を行った。The composition of the decarburized slag used in the test is as shown in Table 1 above. (Conventional example) Decarburized slag with a diameter of 3 to 30 mm
Approximately 10 kg per mass ton was placed above, and desiliconization treatment was carried out by blowing from the upper blowing lance at an oxygen flow rate of 3.6 m 3 (standard condition) / min for about 2 minutes.
【００６４】脱珪スラグを炉内へ残したまま、引き続い
て、脱珪溶銑に粒状鉄鉱石２５ｋｇを炉の上部から上置
きした後、Ｃa Ｏ粉３０ｋｇを上吹き酸素 (３ｍ3(標準
状態)/min)と共に溶銑に約４分間で吹き付け脱りん処理
を行ったところ、処理後の [Ｐ] 濃度は０. ０２３％と
なった。Subsequently, while leaving the desiliconized slag in the furnace, 25 kg of granular iron ore was placed on the desiliconized hot metal from the upper part of the furnace, and 30 kg of CaO powder was blown with oxygen (3 m 3 (standard state)). / min) together with the hot metal for about 4 minutes for dephosphorization treatment, the [P] concentration after the treatment was 0.023%.
【００６５】なお、脱珪スラグと脱りんスラグとの合計
スラグ量はは約８５ｋｇと多かった。 （本発明例１）脱珪処理前に３〜３０mm径の脱炭スラグ
を溶銑１質量トン当たり約１０kgを炉の上部から上置き
し、上吹ランスから３．６m3 (標準状態)/min の酸素流
量で約２分間吹き付けて脱珪処理したところ、溶銑中の
[Ｓi]濃度は０. ０９％となり、生成した脱珪スラグの
塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は０. ７となった。The total slag amount of the desiliconized slag and the dephosphorized slag was as large as about 85 kg. (Invention Example 1) the desiliconization treatment decarburization slag 3~30mm diameter prior to placing on the hot metal 1 mass per ton to about 10kg from the top of the furnace, 3.6 m from the top blowing lance 3 (standard state) / min Spraying for about 2 minutes at an oxygen flow rate of
[Si] concentration becomes 0.09%, basicity of the resulting desiliconization slag (Ca O / Si O 2 mass ratio) became 0.7.
【００６６】炉を傾動して脱珪スラグを排出させたとこ
ろ、約８０％のスラグ排出率が得られた。脱珪溶銑に粒
状鉄鉱石２５ｋｇを炉の上部から上置きした後、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇを溶銑に約４分間吹き付けたとこ
ろ、脱りん処理後の溶銑中の [Ｐ] 濃度は０. ０１３％
となった。When the furnace was tilted to discharge the desiliconized slag, a slag discharge rate of about 80% was obtained. After placing 25 kg of granular iron ore on the desiliconized hot metal from the top of the furnace, 15 kg of CaO powder was blown onto the hot metal for about 4 minutes using top blowing oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas. The [P] concentration in the hot metal after dephosphorization was 0.013%
It became.
【００６７】また、脱珪スラグと脱りんスラグとの合計
スラグ量は約４６ｋｇであり、従来例に比較してスラグ
量が大幅に低減できた。 （本発明例２)脱珪処理前に３〜３０mm径の脱炭スラグ
を溶銑１質量トン当たり１２kgほど、炉の上部から上置
きし、上吹ランスから３．６m3 (標準状態)/min の酸素
流量で約２分間吹き付けて脱珪処理したしたところ、溶
銑中の [Ｓi]濃度は０. ０５％となり、生成した脱珪ス
ラグの塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は０. ６５と
なった。The total slag amount of the desiliconized slag and the dephosphorized slag was about 46 kg, and the slag amount was significantly reduced as compared with the conventional example. (Embodiment 2) prior desiliconization treatment decarburization slag 3~30mm diameter molten iron as 1 weight ton 12 kg, was placed above the top of the furnace, 3.6 m from the top blowing lance 3 (standard state) / min When the was for about 2 minutes blown desiliconization treated with an oxygen flow rate, [Si] concentration in the molten iron becomes 0.05%, resulting desiliconization slag basicity (Ca O / Si O 2 mass ratio) is 0 It was 65.
【００６８】炉を傾動して脱珪スラグを排出させたとこ
ろ、約８０％のスラグ排出率が得られた。脱珪溶銑に粒
状鉄鉱石２５ｋｇを炉の上部から上置きした後、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇを溶銑に約４分間吹き付けたとこ
ろ、脱りん処理後の溶銑中の [Ｐ] 濃度は０. ０１１％
となった。When the furnace was tilted to discharge the desiliconized slag, a slag discharge rate of about 80% was obtained. After placing 25 kg of granular iron ore on the desiliconized hot metal from the top of the furnace, 15 kg of CaO powder was blown onto the hot metal for about 4 minutes using top blowing oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas. [P] concentration in hot metal after dephosphorization was 0.011%
It became.
【００６９】また、脱珪スラグと脱りんスラグとの合計
スラグ量は約４５ｋｇであり、従来例に比較してスラグ
量が大幅に低減できた。 （本発明例３）脱珪処理前に３〜３０mm径の脱炭スラグ
を溶銑１質量トン当たり約１０kgを炉の上部から上置き
し、上吹ランスから３．６m3 (標準状態)/min の酸素流
量で約２分間吹き付けて脱珪処理したところ、溶銑中の
[Ｓi]濃度は０. １０％となり、生成した脱珪スラグの
塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は０. ７となった。The total slag amount of the desiliconized slag and the dephosphorized slag was about 45 kg, and the slag amount was significantly reduced as compared with the conventional example. (Example 3 of the present invention) Before the desiliconization treatment, about 10 kg of decarburized slag having a diameter of 3 to 30 mm per 1 ton of hot metal was placed from the upper part of the furnace, and 3.6 m 3 (standard state) / min from the upper blowing lance. Spraying for about 2 minutes at an oxygen flow rate of
[Si] concentration becomes 10% 0., basicity of the resulting desiliconization slag (Ca O / Si O 2 mass ratio) became 0.7.
【００７０】炉を傾動して脱珪スラグを排出させたとこ
ろ、約８０％のスラグ排出率が得られた。脱珪溶銑に粒
状鉄鉱石２０ｋｇを炉の上部から上置きした後、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇおよびＡl2Ｏ 3 粉３ｋｇを溶銑に約
４分間で吹き付けたところ、脱りん処理後の溶銑中の
[Ｐ] 濃度は０. ００７％となった。The furnace was tilted and the desiliconized slag was discharged.
In addition, a slag discharge rate of about 80% was obtained. Granules on desiliconized hot metal
After placing 20 kg of iron ore on the top of the furnace,
Element (flow rate: 3mThree (Standard condition) / min) as carrier gas
15 kg of CaO powder and AlTwoO ThreeAbout 3kg of powder to hot metal
After spraying for 4 minutes, the hot metal after dephosphorization
[P] concentration was 0.007%.
【００７１】また、脱珪スラグと脱りんスラグとの合計
スラグ量は約４８ｋｇであり、従来例に比較してスラグ
量が大幅に低減できた。 （本発明例４）脱珪処理前に３〜３０mm径の脱炭スラグ
を溶銑１質量トン当たり約１０kgを炉の上部から上置き
し、上吹ランスから３．６m3 (標準状態)/min の酸素流
量で約２分間吹き付けて脱珪処理したところ、溶銑中の
[Ｓi]濃度は０. １０％となり、生成した脱珪スラグの
塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は０. ７となった。The total slag amount of the desiliconized slag and the dephosphorized slag was about 48 kg, and the slag amount was significantly reduced as compared with the conventional example. (Example 4 of the present invention) Before desiliconization, about 10 kg of decarburized slag having a diameter of 3 to 30 mm per 1 ton of hot metal was placed from the upper part of the furnace, and 3.6 m 3 (standard state) / min from the upper blowing lance. Spraying for about 2 minutes at an oxygen flow rate of
[Si] concentration becomes 10% 0., basicity of the resulting desiliconization slag (Ca O / Si O 2 mass ratio) became 0.7.
【００７２】炉を傾動して脱珪スラグを排出させたとこ
ろ、約８０％のスラグ排出率が得られた。脱珪溶銑に粒
状鉄鉱石２０ｋｇを炉の上部から上置きした後、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇおよびＦe2Ｏ 3 粉５ｋｇを溶銑に約
４分間で吹き付けたところ、脱りん処理後の溶銑中の
[Ｐ] 濃度は０. ００５％となった。The furnace was tilted and the desiliconized slag was discharged.
In addition, a slag discharge rate of about 80% was obtained. Granules on desiliconized hot metal
After placing 20 kg of iron ore on the top of the furnace,
Element (flow rate: 3mThree (Standard condition) / min) as carrier gas
15 kg of CaO powder and FeTwoO Three5 kg of powder to hot metal
After spraying for 4 minutes, the hot metal after dephosphorization
The [P] concentration was 0.005%.
【００７３】また、脱珪スラグと脱りんスラグとの合計
スラグ量は約４５ｋｇであり、従来例に比較してスラグ
量が大幅に低減できた。 （比較例１）脱珪処理前に５〜２５mm径の生石灰を溶銑
１質量トン当たり５kgほど、炉の上部から上置きし、上
吹ランスから３．６m3 (標準状態)/min の酸素流量で約
２分間吹き付けて脱珪処理したところ、溶銑中の [Ｓi]
濃度は０. １０％となり、生成した脱珪スラグ中には未
溶融の生石灰が多数残存し、脱珪スラグの流動性は低か
った。The total slag amount of the desiliconized slag and the dephosphorized slag was about 45 kg, and the slag amount was significantly reduced as compared with the conventional example. (Comparative Example 1) Before the desiliconization treatment, quick lime having a diameter of 5 to 25 mm was placed on the upper part of the furnace at a rate of about 5 kg per 1 ton of hot metal, and an oxygen flow rate of 3.6 m 3 (standard state) / min from the upper blowing lance was used. For about 2 minutes to desiliconize, [Si]
The concentration was 0.10%, a large amount of unmelted quicklime remained in the generated desiliconized slag, and the fluidity of the desiliconized slag was low.
【００７４】炉を傾動して脱珪スラグを排出させたが、
スラグ排出率が約７０％と低い値であった。脱珪溶銑に
粒状鉄鉱石２５ｋｇを炉の上部から上置きした後、上吹
酸素（流量：３m3 (標準状態)/min)をキャリアーガスと
してＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けたと
ころ、脱りん処理後の溶銑中の [Ｐ] 濃度は０. ０２７
％と高かった。The desiliconized slag was discharged by tilting the furnace.
The slag discharge rate was a low value of about 70%. After 25 kg of granular iron ore was placed on the desiliconized hot metal from the upper part of the furnace, 15 kg of CaO powder was blown onto the hot metal in about 4 minutes using top blowing oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas. However, the [P] concentration in the hot metal after the dephosphorization treatment is 0.027
% Was high.
【００７５】（比較例２）脱珪処理前に３５〜６０mm径
の脱炭スラグを溶銑１質量トン当たり約１０kgを炉の上
部から上置きし、上吹ランスから３．６m3 (標準状態)/
min の酸素流量で約２分間吹き付けて脱珪処理したとこ
ろ、溶銑中の[Ｓi]濃度は０. ０９％となり、生成した
脱珪スラグ中には未溶融の脱炭スラグが多数残存し、脱
珪スラグの流動性は低かった。(Comparative Example 2) Before desiliconization, about 10 kg of decarburized slag having a diameter of 35 to 60 mm per 1 ton of hot metal was placed above the furnace and 3.6 m 3 from the upper blowing lance (standard condition). /
When the desiliconization treatment was carried out by spraying at an oxygen flow rate of min for about 2 minutes, the [Si] concentration in the hot metal became 0.09%, and many unmelted decarburized slag remained in the generated desiliconized slag. The fluidity of the silicon slag was low.
【００７６】炉を傾動して脱珪スラグを排出させたが、
スラグ排出率が約７０％と低い値であった。脱珪溶銑に
粒状鉄鉱石２５ｋｇを炉の上部から上置きした後、上吹
酸素（流量：３m3 (標準状態)/min)をキャリアーガスと
してＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けたと
ころ、脱りん処理後の溶銑中の [Ｐ] 濃度は０. ０２５
％と高かった。The desiliconized slag was discharged by tilting the furnace.
The slag discharge rate was a low value of about 70%. After 25 kg of granular iron ore was placed on the desiliconized hot metal from the upper part of the furnace, 15 kg of CaO powder was blown onto the hot metal in about 4 minutes using top blowing oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas. However, the [P] concentration in the hot metal after the dephosphorization treatment is 0.025.
% Was high.
【００７７】（比較例３）脱珪処理前に３〜３０mm径の
脱炭スラグを溶銑１質量トン当たり約１０kgを炉の上部
から上置きし、上吹ランスから３．６m3 (標準状態)/mi
n の酸素流量で約２分間吹き付けて脱珪処理したとこ
ろ、溶銑中の [Ｓi]濃度は０. １０％となり、生成した
脱珪スラグの塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は０.
７となった。(Comparative Example 3) Before desiliconization, about 10 kg of decarburized slag having a diameter of 3 to 30 mm per 1 ton of hot metal was placed above the furnace, and 3.6 m 3 from the upper lance (standard condition). / mi
In n oxygen flow rate of blown about 2 minutes was desiliconization treatment, [Si] concentration in the molten iron becomes 10% 0., resulting desiliconization slag basicity (Ca O / Si O 2 mass ratio) is 0 .
It was 7.
【００７８】炉を傾動して脱珪スラグを排出させたとこ
ろ、約８０％のスラグ排出率が得られた。脱珪溶銑に粒
状鉄鉱石２０ｋｇおよび５〜２５mm径の生石灰１５ｋｇ
を上置きした後、上吹酸素（流量：３m3 (標準状態)/mi
n)を溶銑に約４分間で吹き付けたところ、脱りん処理後
の溶銑中の [Ｐ] 濃度は０. ０３０％と高かった。When the furnace was tilted to discharge the desiliconized slag, a slag discharge rate of about 80% was obtained. 20 kg of granular iron ore and 15 kg of quicklime with a diameter of 5 to 25 mm
After placing on top, top-blown oxygen (flow rate: 3m 3 (standard condition) / mi
When n) was sprayed on the hot metal for about 4 minutes, the [P] concentration in the hot metal after the dephosphorization treatment was as high as 0.030%.
【００７９】（比較例４）脱珪処理前に３〜３０mm径の
脱炭スラグを溶銑１ton当たり約１０kgを炉の上部から
上置きし、上吹ランスから１. ５ｍ3(標準状態)/min の
酸素流量で約２分間吹き付けて脱珪処理したところ、溶
銑中の [Ｓi]濃度は０. ３０％となり、生成した脱珪ス
ラグの塩基度（Ｃa Ｏ／Ｓi Ｏ2 質量比）は１. ５とな
った。(Comparative Example 4) Before desiliconization, about 10 kg of decarburized slag having a diameter of 3 to 30 mm per ton of hot metal was placed above the furnace from the top of the furnace, and 1.5 m 3 (standard condition) / min from the upper blowing lance. When the for about 2 minutes blown desiliconization treated with an oxygen flow rate, [Si] concentration in the molten iron becomes 0.30%, resulting desiliconization slag basicity (Ca O / Si O 2 mass ratio) is 1. It was 5.
【００８０】炉を傾動してスラグ排出させたところ、ス
ラグ排出率が約４０％と低い値であった。脱珪溶銑に粒
状鉄鉱石２５ｋｇを炉の上部から上置きした後、上吹酸
素（流量：３m3 (標準状態)/min)をキャリアーガスとし
てＣa Ｏ粉１５ｋｇを溶銑に約４分間で吹き付けたとこ
ろ、脱りん処理後の溶銑中の [Ｐ] 濃度は０. ０３５％
と高かった。When the slag was discharged by tilting the furnace, the slag discharge ratio was a low value of about 40%. After 25 kg of granular iron ore was placed on the desiliconized hot metal from the upper part of the furnace, 15 kg of CaO powder was blown onto the hot metal in about 4 minutes using top blowing oxygen (flow rate: 3 m 3 (standard state) / min) as a carrier gas. However, the [P] concentration in the hot metal after the dephosphorization treatment is 0.035%
And it was high.
【００８１】[0081]
【発明の効果】本発明の方法により、溶銑中の [Ｓi]濃
度が０．１％以下のレベルでも脱りん剤の溶融性を維持
でき、高脱りん率が得られ、しかも溶銑脱珪・脱りん処
理時に発生するスラグ量を低減できる。According to the method of the present invention, even if the [Si] concentration in the hot metal is at a level of 0.1% or less, the melting property of the dephosphorizing agent can be maintained, a high dephosphorization rate can be obtained, and the hot metal desiliconization can be performed. The amount of slag generated during the dephosphorization treatment can be reduced.
【図１】本発明の精錬方法を順に模式的に示す概念図で
あり、図１（ａ）は上底吹転炉で溶銑脱珪する工程を、
図１（ｂ）は上底吹転炉を傾動して脱珪スラグを排出す
る工程を、図１（ｃ）は上底吹転炉で溶銑脱りんする工
程をそれぞれ示す。FIG. 1 is a conceptual diagram schematically showing a refining method of the present invention in order, and FIG. 1 (a) shows a process of hot metal desiliconization in an upper-bottom blowing converter;
FIG. 1B shows a process of tilting the upper-bottom blowing converter to discharge desiliconized slag, and FIG. 1C shows a process of dephosphorizing hot metal in the upper-bottom blowing converter.
【図２】溶銑１質量トン当たり上吹酸素流量と、脱珪処
理後の溶銑中の [Ｓi]濃度およびスピッティング指数と
の関係を示すグラフである。FIG. 2 is a graph showing the relationship between the top blowing oxygen flow rate per 1 ton of hot metal, the [Si] concentration in hot metal after desiliconization treatment, and the spitting index.
【図３】溶銑１質量トン当たり底吹Ａｒ流量と、脱珪処
理後の溶銑中の [Ｓi]濃度およびスピッティング指数と
の関係を示すグラフである。FIG. 3 is a graph showing the relationship between the flow rate of bottom blown Ar per 1 ton of hot metal, the [Si] concentration in hot metal after desiliconization treatment, and the spitting index.
【図４】脱珪時に添加するＣa Ｏ含有物質の性状をパラ
メータとしたスラグ塩基度とスラグ排出率との関係を示
すグラフである。FIG. 4 is a graph showing the relationship between the slag basicity and the slag discharge rate using the properties of the CaO-containing substance added during desiliconization as a parameter.
【図５】脱りん剤の添加方法をパラメータとした溶銑中
の [Ｓi]濃度と脱りん率との関係を示すグラフである。FIG. 5 is a graph showing the relationship between the [Si] concentration in hot metal and the dephosphorization rate using the method of adding the dephosphorizer as a parameter.
【図６】上吹酸素流量と脱りん率との関係を示すグラフ
である。FIG. 6 is a graph showing the relationship between the upper blowing oxygen flow rate and the dephosphorization rate.
【図７】上吹酸素流量とスピッティング指数との関係を
示すグラフである。FIG. 7 is a graph showing the relationship between the top blowing oxygen flow rate and the spitting index.
【図８】溶銑１質量トン当たりの底吹Ａr 流量と脱りん
率との関係を示すグラフである。FIG. 8 is a graph showing the relationship between the bottom blown Ar flow rate per 1 ton of hot metal and the dephosphorization rate.
１：上底吹転炉、 ２：上吹ランス、 ３：底吹羽口、 ４：脱珪溶銑、 ５：脱珪スラグ、 ６：脱りんスラグ、 ７：脱りん溶銑。 1: Top and bottom blowing converter, 2: Top blowing lance, 3: Bottom blowing tuyere, 4: Desiliconized hot metal, 5: Desiliconized slag, 6: Dephosphorized slag, 7: Dephosphorized hot metal.
Claims (2)
ん処理を行う溶銑の精錬方法において、 （ａ）粒径が３〜３０mmの脱炭スラグを溶銑に上置きし
た後、 （ｂ）上吹ランスから酸素を溶銑１質量トン当たり１.
０〜２．５m3 (標準状態)/min 吹き付けながら、底吹羽
口から溶銑１質量トン当たり０. ０５〜０. ６０m3 (標
準状態)/min の攪拌用ガスを吹き込むことにより脱珪処
理を行い、 （ｃ）溶銑中の [Ｓi]濃度を０. １０％以下、脱珪スラ
グの塩基度（Ｃa Ｏ/Ｓi Ｏ2 質量比）を０. ４〜１.
２とした後、 （ｄ）炉内に生成した脱珪スラグを上底吹転炉の傾動に
より炉口から排出し、 （ｅ）脱珪スラグが排出された脱珪溶銑に上吹ランスか
らＣａＯ含有粉を、溶銑１質量トン当たり０. ５〜２．
５m3 (標準状態)/min の酸素をキャリアーガスとして吹
き付けながら、底吹羽口から溶銑１質量トン当たり０.
０５〜０. ６０m3 (標準状態)/min の攪拌用ガスを吹き
込むことにより脱りん処理を行うことを特徴とする溶銑
の精錬方法。1. A method for refining hot metal in which hot metal is charged into an upper-bottom blower and subjected to desiliconization and dephosphorization treatment, wherein (a) decarburized slag having a particle size of 3 to 30 mm is placed on the hot metal. After that, (b) oxygen is supplied from the top blowing lance at a rate of 1.
0 to 2.5 m 3 (standard condition) / min Desiliconization treatment by blowing 0.05 to 0.60 m 3 (standard condition) / min stirring gas per 1 ton of hot metal from the bottom nozzle while spraying. was carried out, (c) the molten iron [Si] concentration 0.10% or less, 0.4 to 1 desiliconization slag basicity (Ca O / Si O 2 mass ratio).
After that, (d) the desiliconized slag generated in the furnace is discharged from the furnace port by tilting the upper-bottom blowing converter, and (e) the desiliconized molten iron from which the desiliconized slag has been discharged is supplied from the top blowing lance to CaO. The contained powder is added in an amount of 0.5 to 2.
While spraying 5 m 3 (standard condition) / min of oxygen as a carrier gas, the bottom blown tuyere has a flow rate of 0.
A method for refining hot metal, comprising performing a dephosphorization treatment by blowing a stirring gas at a rate of 0.5 to 0.60 m 3 (standard state) / min.
e2Ｏ3 の少なくとも一種を含有することを特徴とする請
求項１に記載の溶銑の精錬方法。2. The CaO-containing powder comprises Al 2 O 3 and F
hot metal process refining according to claim 1, characterized in that it contains at least one e 2 O 3.
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| JP2000231697A JP2002047509A (en) | 2000-07-31 | 2000-07-31 | Method for refining molten iron |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000231697A JP2002047509A (en) | 2000-07-31 | 2000-07-31 | Method for refining molten iron |
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|---|---|
| JP2002047509A true JP2002047509A (en) | 2002-02-15 |
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ID=18724497
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012108529A1 (en) * | 2011-02-10 | 2012-08-16 | 新日本製鐵株式会社 | Method for desiliconizing and dephosphorizing hot metal |
| JP2014159629A (en) * | 2013-01-22 | 2014-09-04 | Jfe Steel Corp | Preliminary treatment method of molten iron by converter |
| JP2015140462A (en) * | 2014-01-29 | 2015-08-03 | 株式会社神戸製鋼所 | Dephosphorization processing method for changing top-blown condition in converter type vessel |
| KR20150092298A (en) * | 2013-01-18 | 2015-08-12 | 제이에프이 스틸 가부시키가이샤 | Molten iron pre-treatment method |
| US9315875B2 (en) | 2011-07-19 | 2016-04-19 | Jfe Steel Corporation | Method of refining molten iron |
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| US9920390B2 (en) | 2012-01-19 | 2018-03-20 | Jfe Steel Corporation | Method for preliminary treatment of molten iron |
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2000
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|---|---|---|---|---|
| WO2012108529A1 (en) * | 2011-02-10 | 2012-08-16 | 新日本製鐵株式会社 | Method for desiliconizing and dephosphorizing hot metal |
| JP5170348B2 (en) * | 2011-02-10 | 2013-03-27 | 新日鐵住金株式会社 | Hot metal desiliconization and phosphorus removal methods |
| CN103370426A (en) * | 2011-02-10 | 2013-10-23 | 新日铁住金株式会社 | Method for desiliconizing and dephosphorizing hot metal |
| US9315875B2 (en) | 2011-07-19 | 2016-04-19 | Jfe Steel Corporation | Method of refining molten iron |
| US9920390B2 (en) | 2012-01-19 | 2018-03-20 | Jfe Steel Corporation | Method for preliminary treatment of molten iron |
| KR20150092298A (en) * | 2013-01-18 | 2015-08-12 | 제이에프이 스틸 가부시키가이샤 | Molten iron pre-treatment method |
| KR101701658B1 (en) * | 2013-01-18 | 2017-02-01 | 제이에프이 스틸 가부시키가이샤 | Method for pretreating molten iron |
| JP2014159629A (en) * | 2013-01-22 | 2014-09-04 | Jfe Steel Corp | Preliminary treatment method of molten iron by converter |
| JP2015140462A (en) * | 2014-01-29 | 2015-08-03 | 株式会社神戸製鋼所 | Dephosphorization processing method for changing top-blown condition in converter type vessel |
| JP2016079462A (en) * | 2014-10-17 | 2016-05-16 | 新日鐵住金株式会社 | Method for refining hot pig iron |
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