JPH0711020B2 - Dephosphorization method for molten steel - Google Patents
Dephosphorization method for molten steelInfo
- Publication number
- JPH0711020B2 JPH0711020B2 JP4006373A JP637392A JPH0711020B2 JP H0711020 B2 JPH0711020 B2 JP H0711020B2 JP 4006373 A JP4006373 A JP 4006373A JP 637392 A JP637392 A JP 637392A JP H0711020 B2 JPH0711020 B2 JP H0711020B2
- Authority
- JP
- Japan
- Prior art keywords
- slag
- molten steel
- dephosphorization
- caf
- cao
- 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.)
- Expired - Lifetime
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
- Treatment Of Steel In Its Molten State (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、取鍋内の溶鋼にフラ
ックスを添加して脱燐する溶鋼の脱燐方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dephosphorizing molten steel by adding flux to the molten steel in a ladle to dephosphorize the molten steel.
【０００２】[0002]
【従来の技術】溶鉄の脱燐は、高炉から転炉に運搬され
る途中の溶銑、転炉にて脱炭精錬されている溶鋼、又は
転炉から出鋼された取鍋内の溶鋼に対して、脱燐スラグ
を添加することによりなされている。2. Description of the Related Art Dephosphorization of molten iron is performed on molten iron being transported from the blast furnace to the converter, molten steel being decarburized and refined in the converter, or molten steel in a ladle tapped from the converter. Then, the dephosphorization slag is added.
【０００３】この場合に、脱燐反応を効率的に進行さ
せ、低燐濃度の溶銑及び溶鋼を得るためには、脱燐スラ
グの選択が重要である。スラグの脱燐能が高い程、より
低いフラックス添加原単位（脱燐処理すべき溶湯１トン
当たりに対するフラックスの添加量（kg）のことをい
う）で溶銑及び溶鋼の燐濃度を低下させることができ
る。従来の脱燐方法においては、転炉にて添加されるも
のとして主にＣａＯ−ＳｉＯ2 −ＦｅＯ系スラグ、溶銑
及び溶鋼に対して添加されるものとしてＣａＯ−ＣａＦ
2 −ＳｉＯ2 −ＦｅＯ系スラグ及びＮａ2 Ｏ−ＳｉＯ2
系スラグがある。これらのスラグの脱燐能（燐分配値）
を表１に示す。In this case, the selection of the dephosphorization slag is important in order to efficiently proceed the dephosphorization reaction and obtain hot metal and molten steel having a low phosphorus concentration. The higher the dephosphorization capacity of slag, the lower the basic unit of flux addition (meaning the amount of flux added (kg) per ton of molten metal to be dephosphorized), the lower the phosphorus concentration of hot metal and molten steel. it can. In the conventional dephosphorization method, CaO—Ca 2 —FeO-based slag is mainly added to the converter, and CaO—CaF is added to the hot metal and molten steel.
2 -SiO 2 -FeO slag and Na 2 O-SiO 2
There is a system slag. Dephosphorization capacity of these slags (Phosphorus partition value)
Is shown in Table 1.
【０００４】但し、表１において、スラグＡは溶銑処理
に使用され、Ｎａ2Ｏ−ＳｉＯ2 系又はＣａＯ−ＣａＦ
2 −ＳｉＯ2−ＦｅＯ系のスラグであり、スラグＢは転
炉にて添加され、ＣａＯ−ＳｉＯ2 −ＦｅＯ系のスラグ
であり、スラグＣは溶鋼処理に使用され、ＣａＯ−Ｃａ
Ｆ2 −ＳｉＯ2 −ＦｅＯ系のスラグである。ここで、燐
分配値とは、脱燐処理後のスラグ中燐濃度（Ｐ）と、溶
鉄中燐濃度［Ｐ］との比（Ｐ）／［Ｐ］をいう。However, in Table 1, slag A is used for hot metal treatment, and Na 2 O-SiO 2 system or CaO-CaF is used.
A 2 -SiO 2 -FeO slag, the slag B is added in a converter furnace, an slag CaO-SiO 2 -FeO system, slag C is used in the molten steel processing, CaO-Ca
F 2 is a slug of -SiO 2 -FeO system. Here, the phosphorus distribution value means a ratio (P) / [P] of the phosphorus concentration (P) in the slag after the dephosphorization treatment and the phosphorus concentration [P] in the molten iron.
【０００５】[0005]
【発明が解決しようとする課題】このように、従来の脱
燐処理用のスラグにおいては、脱燐に有利である低温処
理が可能の溶銑添加の場合でも、燐分配値は高々１００
０であり、溶鋼添加の場合は数百にすぎない。このため
所要値に燐濃度を低下させるためのスラグ原単位が高
く、脱燐コストが高い。また、操業上、スラグの添加量
（フラックス原単位）の増加には限界がある。このた
め、極低燐濃度の溶鉄を得ようとしても脱燐処理により
低下させうる燐濃度には限界がある。As described above, in the conventional slag for the dephosphorization treatment, the phosphorus distribution value is at most 100 even in the case of the addition of the hot metal which is advantageous for the dephosphorization and which enables the low temperature treatment.
It is 0, and in the case of adding molten steel, it is only several hundreds. Therefore, the slag basic unit for reducing the phosphorus concentration to the required value is high, and the dephosphorization cost is high. In addition, there is a limit to the amount of slag added (flux basic unit) in operation. Therefore, there is a limit to the phosphorus concentration that can be reduced by the dephosphorization treatment even if molten iron with an extremely low phosphorus concentration is to be obtained.
【０００６】この発明は、かかる事情に鑑みてなされた
ものであって、高脱燐能を有し、スラグ原単位を低下さ
せて脱燐コストを低下させることができ、極低燐濃度の
鋼材を容易に製造することができる溶鋼の脱燐方法を提
供することを目的とする。The present invention has been made in view of the above circumstances, and has a high dephosphorization capacity, can reduce the dephosphorization cost by reducing the slag basic unit, and has a very low phosphorus concentration. It is an object of the present invention to provide a dephosphorization method for molten steel that can be easily manufactured.
【０００７】[0007]
【課題を解決するための手段】この発明に係る溶鋼の脱
燐方法は、溶鋼の温度に応じて、フラックス添加原単位
で少なくとも１３．８kg／トンのＮａ2 Ｏ及び少なくと
も４６．２kg／トンのＣａＯ，ＦｅＯ，ＣａＦ2 を主成
分とするＮａ2 Ｏ以外の成分を含むように調整したフラ
ックスを、溶鋼に添加する工程と、該フラックスを滓化
する工程と、溶鋼を撹拌し、該スラグと溶鋼とを反応さ
せる工程と、を有し、処理後におけるスラグ組成が下記
不等式にて示す組成を有するＣａＯ−ＣａＦ2 −ＳｉＯ
2 を系スラグにＮａ2 Ｏを３重量％以下の割合で含有す
ることを特徴とする。 （ＳｉＯ2 ）≧７ １０≦（ＣａＦ2 ）≦４２ （ＣａＯ）≦３．１７・（ＳｉＯ2 ） ＋１．７・（ＣａＦ2 ） （ＣａＯ）／（ＳｉＯ2 ）≧２．１ 但し、（ ）はその成分の濃度（重量％）を示し、 （ＣａＯ）＋（ＣａＦ2 ）＋（ＳｉＯ2 ） ＝１００と規格化する。Means for Solving the Problems] dephosphorization method of molten steel according to the present invention, depending on the temperature of molten steel, at least 13.8 kg / ton Flux added per unit Na 2 O and at least 46.2Kg / ton CaO, FeO, CaF 2 as a main component, a flux adjusted to contain components other than Na 2 O, a step of adding to the molten steel, a step of slagging the flux, stirring the molten steel, and the slag CaO—CaF 2 —SiO having a composition in which the slag composition after treatment has a composition represented by the following inequality.
2 is contained in a system slag containing Na 2 O in an amount of 3% by weight or less. (SiO 2 ) ≧ 7 10 ≦ (CaF 2 ) ≦ 42 (CaO) ≦ 3.17 · (SiO 2 ) + 1.7 · (CaF 2 ) (CaO) / (SiO 2 ) ≧ 2.1 However, () Indicates the concentration (% by weight) of the component and is standardized as (CaO) + (CaF 2 ) + (SiO 2 ) = 100.
【０００８】[0008]
【実施例】以下添付の図面を参照して、この発明につい
て具体的に説明する。この発明に係る脱燐スラグは生石
灰（ＣａＯ）、フッ化カルシウム（ＣａＦ2）及びシリ
カ（ＳｉＯ2 ）からなる３元系スラグをベ―スにし、こ
のスラグに酸化ナトリウム（Ｎａ2 Ｏ）を少量含有させ
たものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the accompanying drawings. The dephosphorization slag according to the present invention is based on a ternary slag consisting of quick lime (CaO), calcium fluoride (CaF 2 ) and silica (SiO 2 ), and a small amount of sodium oxide (Na 2 O) is added to this slag. It is included.
【０００９】本願発明者等は、脱燐能が高いスラグを開
発すべく種々実験研究をかさねた結果、このＣａＯ−Ｃ
ａＦ2 −ＳｉＯ2 系スラグにおいて、トリカルシウムシ
リケ―ト（３ＣａＯ・ＳｉＯ2 ）及び生石灰が共存する
領域になるように組成を調整したスラグが高脱燐能を有
していることを見い出した。更に、このようなスラグに
酸化ナトリウムを含有させると一層脱燐能が上昇する。
また、必要に応じて、酸素ポテンシャルを高めるために
酸化鉄（ＦｅＯ）を含有させてもよい。The inventors of the present application conducted various experimental studies to develop a slag having a high dephosphorization ability, and as a result, the CaO--C
In the aF 2 -SiO 2 slag, it was found that the slag whose composition was adjusted so that the tricalcium silicate (3CaO · SiO 2 ) and quick lime coexist had a high dephosphorization ability. . Further, the inclusion of sodium oxide in such slag further increases the dephosphorization ability.
Further, if necessary, iron oxide (FeO) may be contained in order to increase the oxygen potential.
【００１０】本願発明はこのような知見に基づいてされ
たものであって、溶銑又は溶鋼の脱燐処理温度において
以下に規定するような組成範囲になるように添加スラグ
組成をコントロ―ルする。先ず、溶鋼の脱燐処理に使用
するスラグについて、ＣａＯ−ＣａＦ2 −ＳｉＯ2 三元
系スラグの状態図である図１に基いて説明する。脱燐処
理温度において、スラグが溶融している必要があるた
め、ＣａＯ−ＣａＦ2 −ＳｉＯ2 の三元系スラグにおい
て、その融点が処理温度より２００℃高い温度と２００
℃低い温度との間になるような組成であることが必要で
ある。溶鋼の脱燐処理においては、通常処理温度が１５
７５℃であるから、上記組成は、図１において、１７７
５℃と１３７５℃の液相線（それぞれ１７５０℃及び１
３５０℃の液相線の近傍）に挟まれた領域である。The present invention is based on such knowledge, and controls the additive slag composition so that the composition range as defined below is obtained at the dephosphorization treatment temperature of the hot metal or molten steel. First, the slag used for the dephosphorization treatment of molten steel will be described based on FIG. 1, which is a state diagram of a CaO—CaF 2 —SiO 2 ternary slag. Since the slag needs to be molten at the dephosphorization treatment temperature, the ternary slag of CaO—CaF 2 —SiO 2 has a melting point of 200 ° C. higher than the treatment temperature and 200 ° C.
It is necessary that the composition is such that the temperature is lower by 0 ° C. In the dephosphorization treatment of molten steel, the treatment temperature is usually 15
Since it is 75 ° C., the composition is 177 in FIG.
Liquidus of 5 ℃ and 1375 ℃ (1750 ℃ and 1
It is a region sandwiched between (around the liquidus line of 350 ° C.).
【００１１】液相線が１３７５℃より低い領域は、スラ
グが溶融しやすい組成である点で好ましいが、ＣａＦ2
の濃度が高くなるので耐火物の溶損が激しくなるととも
に脱燐能が低くなるという欠点がある。このため、この
発明においては融点が１３７５℃以上、つまり処理温度
より２００℃低い温度以上になるようにスラグ組成をコ
ントロ―ルする。また、融点が処理温度より高いと、フ
ラックスが溶融しないと考えられるが、この発明に係る
脱燐スラグにおいては、これらの三成分の外にＮａ2 Ｏ
も含有しているので、ＣａＯ−ＣａＦ2 −ＳｉＯ2 系ス
ラグの状態図において１７７５℃の液相線の領域であっ
ても、現実に使用されるスラグは溶融状態にある。従っ
て、この発明においては、三元系スラグ組成を処理温度
より２００℃高い温度以下の融点を有する領域とする。The region where the liquidus is lower than 1375 ° C. is preferable because the composition is such that the slag is easily melted, but CaF 2
As a result, the refractory material is more likely to be melted and damaged, and the dephosphorization ability is lowered. Therefore, in the present invention, the slag composition is controlled so that the melting point is 1375 ° C. or higher, that is, the temperature is 200 ° C. lower than the treatment temperature. Further, when the melting point is higher than the treatment temperature, it is considered that the flux does not melt, but in the dephosphorization slag according to the present invention, Na 2 O is contained in addition to these three components.
Since it also contains, the slag actually used is in a molten state even in the region of the liquidus line of 1775 ° C. in the phase diagram of the CaO—CaF 2 —SiO 2 based slag. Therefore, in the present invention, the ternary slag composition is set to a region having a melting point equal to or higher than the treatment temperature by 200 ° C. or less.
【００１２】この発明においては、トリカルシウムシリ
ケ―トと生石灰との共存領域のスラグを使用するから、
２ＣａＯ・ＳｉＯ2 が共存する領域はこの発明に係る脱
燐スラグの組成範囲から外れる。In the present invention, since the slag in the coexisting region of tricalcium silicate and quick lime is used,
The region where 2CaO.SiO 2 coexists is out of the composition range of the dephosphorization slag according to the present invention.
【００１３】ＣａＯが単体で存在する領域においては、
以下のように組成範囲が決められる。つまり、処理温度
より２００℃高い温度及び２００℃低い温度の液相線に
て挾まれた領域であって、これらの液相線が、ＣａＯ単
体領域とトリカルシウムシリケ―ト・生石灰共存領域と
の境界線と交差する点Ｘ0 及びＹ0 から、これらの液相
線にそってＣａＦ2 の割合が１０％多い点Ｘ及びＹを結
ぶ直線により仕切られた領域である。脱燐能を高めるた
めにはＣａＯの活量を高めることが望ましいが、ＣａＯ
の濃度を高めるとＣａＦ2 の濃度も高くなって好ましく
ないので、ＣａＦ2 の濃度が１０％増加する領域までを
この発明に係る脱燐スラグの組成範囲とする。In the region where CaO exists alone,
The composition range is determined as follows. In other words, it is a region sandwiched by liquidus lines at a temperature of 200 ° C. higher and 200 ° C. lower than the processing temperature, and these liquidus lines are a CaO simple substance region and a tricalcium silicate / quick lime coexisting region. It is a region partitioned by a straight line connecting points X 0 and Y 0 intersecting the boundary line of X and Y 0 along the liquidus line and connecting points X and Y where the proportion of CaF 2 is 10% higher. It is desirable to increase the activity of CaO in order to improve the dephosphorization ability.
When the concentration of CaF 2 is increased, the concentration of CaF 2 is also increased, which is not preferable. Therefore, the composition range of the dephosphorization slag according to the present invention is set to a region where the concentration of CaF 2 increases by 10%.
【００１４】以上の如くして決定される脱燐処理後のス
ラグの組成範囲は、図１に斜線にて示す領域である。つ
まり、ＣａＯ、ＣａＦ2 及びＳｉＯ2 が上記組成範囲に
なるように相対的な割合をきめ、このスラグをベ―スに
してＮａ2 Ｏを３重量％以下の割合で含有させる。Ｎａ
2 Ｏが高い程燐分配値が高いが、Ｎａ2 Ｏのコストが高
いこと、Ｎａ2 Ｏが多いと耐火物の溶損が激しくなるこ
と、及び粉塵が出やすくなること等の理由から、フラッ
クス添加原単位で少なくとも１３．８kg／トンのＮａ2
Ｏ及び少なくとも４６．２kg／トンのＣａＯ，ＦｅＯ，
ＣａＦ2 を主成分とするＮａ2 Ｏ以外の成分からなるフ
ラックスを溶鋼に添加し、かつ、脱燐処理後のＮａ2 Ｏ
の濃度を３％以下に設定する。必要に応じて、酸素ポテ
ンシャルを維持するために、ＦｅＯを含有させてもよ
い。The composition range of the slag after the dephosphorization treatment, which is determined as described above, is the hatched area in FIG. That is, the relative proportions of CaO, CaF 2 and SiO 2 are determined so as to fall within the above composition range, and this slag is used as a base to contain Na 2 O in a proportion of 3% by weight or less. Na
The higher the 2 O, the higher the phosphorus distribution value, but the higher the cost of Na 2 O, the more the Na 2 O is added, the more the melting loss of the refractory material becomes severe, and the more easily dust is generated. Addition unit of at least 13.8 kg / ton Na 2
O and at least 46.2 kg / ton CaO, FeO,
Adding a flux comprising a component other than Na 2 O mainly composed of CaF 2 in the molten steel, and, Na 2 O after dephosphorization
Concentration of 3% or less. If necessary, FeO may be contained in order to maintain the oxygen potential.
【００１５】図２は、溶銑に添加する場合の脱燐処理後
の脱燐スラグの組成範囲を斜線領域にて示す。組成範囲
の決定方法は、溶鋼に添加すべきスラグの場合と同様で
ある。溶銑に対して脱燐処理する場合は、処理温度が通
常１３００℃と低いので、組成範囲は溶鋼を脱燐処理す
る場合に比して、ＣａＦ2 の割合が高い側に移動してい
る。FIG. 2 shows the composition range of the dephosphorization slag after the dephosphorization treatment when it is added to the hot metal, in the shaded area. The method for determining the composition range is the same as that for the slag to be added to the molten steel. When the dephosphorization treatment is performed on the hot metal, the treatment temperature is usually as low as 1300 ° C., so that the composition range is shifted to the side where the proportion of CaF 2 is higher than when the molten steel is dephosphorized.
【００１６】このように脱燐に最適なスラグ組成範囲は
処理温度により異なり、この溶鋼処理及び溶銑処理の場
合を包含する組成範囲（Ｎａ2 Ｏを除く）は図３のＣａ
Ｏ−ＣａＦ2 −ＳｉＯ2 系スラグの状態図に斜線領域に
て示すようになる。この領域は下記不等式にて現わされ
る。 （ＳｉＯ2 ）≧７ １０≦（ＣａＦ2 ）≦４２ （ＣａＯ）≦３．１７・（ＳｉＯ2 ） ＋１．７・（ＣａＦ2 ） （ＣａＯ）／（ＳｉＯ2 ）≧２．１ 但し、（ ）はその成分の濃度（重量％）を示す。ま
た、（ＣａＯ）＋（ＣａＦ2 ）＋（ＳｉＯ2 ）＝１００
と規格化する。Thus, the optimum slag composition range for dephosphorization differs depending on the treatment temperature, and the composition range (excluding Na 2 O) including the cases of this molten steel treatment and hot metal treatment is Ca in FIG.
The shaded region is shown in the state diagram of the O—CaF 2 —SiO 2 slag. This region is represented by the following inequality. (SiO 2 ) ≧ 7 10 ≦ (CaF 2 ) ≦ 42 (CaO) ≦ 3.17 · (SiO 2 ) + 1.7 · (CaF 2 ) (CaO) / (SiO 2 ) ≧ 2.1 However, () Indicates the concentration (% by weight) of the component. Also, (CaO) + (CaF 2 ) + (SiO 2 ) = 100
And standardize.
【００１７】この場合においても、フラックス添加原単
位で少なくとも１３．８kg／トンのＮａ2 Ｏ及び少なく
とも４６．２kg／トンのＣａＯ，ＦｅＯ，ＣａＦ2 を主
成分とするＮａ2 Ｏ以外の成分からなるフラックスを溶
鋼に添加し、かつ、脱燐処理後のＮａ2 Ｏの濃度を３重
量％に設定する。Also in this case, the flux addition unit is at least 13.8 kg / ton of Na 2 O and at least 46.2 kg / ton of CaO, FeO and components other than Na 2 O containing CaF 2 as the main component. Flux is added to the molten steel, and the concentration of Na 2 O after the dephosphorization treatment is set to 3% by weight.
【００１８】次に、この発明の実施例について具体的に
説明する。まず溶鋼を脱燐処理した場合の実施例につい
て説明する。５kgの高周波炉により大気下でマグネシア
ルツボ中で低炭素鋼を溶解した後、上記組成になるよう
に配合計算したフラックスを溶鋼１トンに対して６０kg
の割合で添加した。その後、マグネシア製パイプを溶鋼
中に浸漬してアルゴンガスを０．５Ｎｌ／分の流速で溶
鋼中に吹き込み、溶鋼を撹拌して脱燐反応を促進させ
た。約２０分の反応期間中、溶鋼及スラグからサンプリ
ングして組成を分析した。その結果を表２及表３に示
す。表３中に示した脱燐処理前の各組成をフラックス添
加原単位にそれぞれ換算すると、Ｎａ2 Ｏが１３．８kg
／トンになり、Ｎａ2Ｏ以外の成分が４６．２kg／トン
になる。Next, embodiments of the present invention will be specifically described. First, an example of the case where molten steel is dephosphorized will be described. After melting low-carbon steel in a magnesia crucible in the atmosphere with a 5 kg high-frequency furnace, the flux calculated to obtain the above composition was 60 kg per ton of molten steel.
Was added. Then, a magnesia pipe was immersed in molten steel, and argon gas was blown into the molten steel at a flow rate of 0.5 Nl / min to stir the molten steel to accelerate the dephosphorization reaction. During the reaction period of about 20 minutes, the composition was analyzed by sampling the molten steel and the slag. The results are shown in Tables 2 and 3. When the composition before dephosphorization shown in Table 3 is converted into the basic unit of flux addition, Na 2 O is 13.8 kg.
/ Ton, and the components other than Na 2 O become 46.2 kg / ton.
【００１９】この表２及び表３に示すようにフラックス
添加後、１０分経過すると、溶鋼中の燐濃度が１０ｐｐ
ｍ以下になり、燐分配値が１０００を超え、従来の脱燐
スラグでは得られない高脱燐能で溶鋼が脱燐された。As shown in Tables 2 and 3, 10 minutes after the flux was added, the phosphorus concentration in the molten steel was 10 pp.
m or less, the phosphorus distribution value exceeded 1000, and the molten steel was dephosphorized with a high dephosphorization ability that cannot be obtained by the conventional dephosphorization slag.
【００２０】表４は、図１（溶鋼脱燐処理）の斜線領域
に示す範囲にコントロ―ルされたこの発明に係るスラグ
の燐配分値を、図１の斜線領域から外れる組成のスラグ
の燐分配値と比較して示す。なお、燐分配値は脱燐スラ
グを添加した後、２０分経過して得られた燐配分値であ
る。また、図１中の丸数字１，丸数字２，丸数字３，丸
数字４は夫々表４中の比較例１，２，３，４のスラグの
組成を示す。Table 4 shows the phosphorus distribution value of the slag according to the present invention, which is controlled within the range shown in the shaded area of FIG. 1 (molten steel dephosphorization treatment), and the phosphorus content of the slag whose composition deviates from the shaded area of FIG. It is shown in comparison with the distribution value. The phosphorus distribution value is the phosphorus distribution value obtained 20 minutes after the addition of dephosphorization slag. In addition, circled numbers 1, circled numbers 2, circled numbers 3 and circled numbers 4 in FIG. 1 indicate the compositions of the slags of Comparative Examples 1, 2, 3, and 4 in Table 4, respectively.
【００２１】この表４及び図１から明らかなように、こ
の発明にて規定される組成範囲から外れるスラグ（比較
例１，２，３，４）は、Ｎａ2 Ｏを含有していても、こ
の発明に係るスラグよりも燐分配値が極めて低い。比較
例１のスラグは他の比較例のスラグよりも燐分配値が多
少高いが、ＣａＦ2 の濃度が高いため、耐火物の浸食が
激しいので実用的ではない。As is clear from Table 4 and FIG. 1, even if the slags (Comparative Examples 1, 2 , 3, 4) out of the composition range specified in the present invention contain Na 2 O, The phosphorus distribution value is extremely lower than that of the slag according to the present invention. Although the slag of Comparative Example 1 has a slightly higher phosphorus distribution value than the slags of the other Comparative Examples, it has a high CaF 2 concentration and is therefore not practical because the refractory erodes severely.
【００２２】一方、図４はこの発明に係るスラグの燐分
配値Ｌp を、従来の脱燐スラグの燐分配値と比較して示
すグラフである。燐分配値は温度に依存するため、図の
横軸には温度をとっている。図中破線はＣａＯ−ＣａＦ
2系、一点鎖線はＮａ2 Ｏ−ＳｉＯ2 系スラグのＬp を
示し、破線にて囲む領域はＣａＯ−Ｎａ2 Ｏ−ＳｉＯ2
系スラグのＬp を示す。この図４から明らかなように、
この発明に係るスラグは全ての温度において、従来のス
ラグよりも数倍乃至数十倍高い燐分配値を有している。On the other hand, FIG. 4 is a graph showing the phosphorus distribution value L p of the slag according to the present invention in comparison with the phosphorus distribution value of the conventional dephosphorization slag. Since the phosphorus distribution value depends on the temperature, the horizontal axis of the figure shows the temperature. The broken line in the figure is CaO-CaF.
2 system, the one-dot chain line shows L p of Na 2 O—SiO 2 system slag, and the region surrounded by the broken line is CaO—Na 2 O—SiO 2
L p of the system slag is shown. As is clear from FIG. 4,
The slag according to the present invention has a phosphorus distribution value that is several to several tens of times higher than that of the conventional slag at all temperatures.
【００２３】次に、溶銑に対して脱燐処理した場合の実
施例について説明する。表６はこの発明に係る脱燐スラ
グの燐分配値をこの発明にて規定する組成から外れるス
ラグの燐分配値と比較して示し、表７は各スラグの組成
を示す。Next, an example of the case where the hot metal is dephosphorized will be described. Table 6 shows the phosphorus distribution value of the dephosphorized slag according to the present invention in comparison with the phosphorus distribution value of the slag deviating from the composition specified in the present invention, and Table 7 shows the composition of each slag.
【００２４】なお、この表６における燐分配値は、フラ
ックス添加後３０分経過したときの燐分配値であり、こ
の発明に係るスラグにおいては約１００００という極め
て高い値が得られている。このように、この発明に係る
スラグにおいては、処理温度に拘らず、従来のスラグで
は得られない極めて高い燐分配値が得られる。The phosphorus distribution value in Table 6 is the phosphorus distribution value 30 minutes after the addition of the flux, and the slag according to the present invention has an extremely high value of about 10,000. As described above, in the slag according to the present invention, an extremely high phosphorus distribution value which cannot be obtained by the conventional slag is obtained regardless of the treatment temperature.
【００２５】[0025]
【表１】 [Table 1]
【００２６】[0026]
【表２】 [Table 2]
【００２７】[0027]
【表３】 [Table 3]
【００２８】[0028]
【表４】 [Table 4]
【００２９】[0029]
【表５】 [Table 5]
【００３０】[0030]
【表６】 [Table 6]
【００３１】[0031]
【表７】 [Table 7]
【００３２】[0032]
【発明の効果】以上詳細に説明したように、この発明に
よれば、スラグの脱燐能が極めて高いから、スラグの添
加原単位を低下させ、脱燐コストを低下させることがで
きる。また、この発明によれば、従来の脱燐スラグでは
得られない極低燐濃度の鋼材を容易に製造することがで
きる。As described above in detail, according to the present invention, since the dephosphorization ability of slag is extremely high, it is possible to reduce the addition unit of slag and the dephosphorization cost. Further, according to the present invention, it is possible to easily manufacture a steel material having an extremely low phosphorus concentration which cannot be obtained by the conventional dephosphorization slag.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の脱燐方法に用いられるスラグ組成を示
す状態図。FIG. 1 is a state diagram showing a slag composition used in the dephosphorization method of the present invention.
【図２】本発明の脱燐方法に用いられるスラグ組成を示
す状態図。FIG. 2 is a state diagram showing a slag composition used in the dephosphorization method of the present invention.
【図３】本発明の脱燐方法に用いられるスラグ組成を示
す状態図。FIG. 3 is a state diagram showing a slag composition used in the dephosphorization method of the present invention.
【図４】本発明の実施例の効果を説明するためのグラフ
図である。FIG. 4 is a graph chart for explaining the effect of the embodiment of the present invention.
Claims (1)
単位で少なくとも１３．８kg／トンのＮａ2 Ｏ及び少な
くとも４６．２kg／トンのＣａＯ，ＦｅＯ，ＣａＦ2 を
主成分とするＮａ2 Ｏ以外の成分を含むように調整した
フラックスを、溶鋼に添加する工程と、 該フラックスを滓化する工程と、 溶鋼を撹拌し、該スラグと溶鋼とを反応させる工程と、
を有し、 処理後におけるスラグ組成が下記不等式にて示す組成を
有するＣａＯ−ＣａＦ2 −ＳｉＯ2 を系スラグにＮａ2
Ｏを３重量％以下の割合で含有することを特徴とする溶
鋼の脱燐方法。 （ＳｉＯ2 ）≧７ １０≦（ＣａＦ2 ）≦４２ （ＣａＯ）≦３．１７・（ＳｉＯ2 ） ＋１．７・（ＣａＦ2 ） （ＣａＯ）／（ＳｉＯ2 ）≧２．１ 但し、（ ）はその成分の濃度（重量％）を示し、 （ＣａＯ）＋（ＣａＦ2 ）＋（ＳｉＯ2 ） ＝１００と規格化する。1. Other than Na 2 O containing at least 13.8 kg / ton of Na 2 O and at least 46.2 kg / ton of CaO, FeO, CaF 2 as main components depending on the temperature of molten steel. A step of adding a flux adjusted so as to contain the component to molten steel, a step of slagging the flux, a step of stirring the molten steel and reacting the slag with the molten steel,
CaO—CaF 2 —SiO 2 having a composition of which the slag composition after treatment is represented by the following inequality is added to the system slag as Na 2
A dephosphorization method for molten steel, characterized by containing O in an amount of 3% by weight or less. (SiO 2 ) ≧ 7 10 ≦ (CaF 2 ) ≦ 42 (CaO) ≦ 3.17 · (SiO 2 ) + 1.7 · (CaF 2 ) (CaO) / (SiO 2 ) ≧ 2.1 However, () Indicates the concentration (% by weight) of the component and is standardized as (CaO) + (CaF 2 ) + (SiO 2 ) = 100.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4006373A JPH0711020B2 (en) | 1992-01-17 | 1992-01-17 | Dephosphorization method for molten steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4006373A JPH0711020B2 (en) | 1992-01-17 | 1992-01-17 | Dephosphorization method for molten steel |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP45185A Division JPS61159506A (en) | 1985-01-08 | 1985-01-08 | Slag for dephosphorizing molten iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0543923A JPH0543923A (en) | 1993-02-23 |
| JPH0711020B2 true JPH0711020B2 (en) | 1995-02-08 |
Family
ID=11636577
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4006373A Expired - Lifetime JPH0711020B2 (en) | 1992-01-17 | 1992-01-17 | Dephosphorization method for molten steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0711020B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110592321B (en) * | 2019-09-30 | 2022-04-22 | 舞阳钢铁有限责任公司 | LF refining method for quickly desulfurizing high-sulfur molten steel |
-
1992
- 1992-01-17 JP JP4006373A patent/JPH0711020B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0543923A (en) | 1993-02-23 |
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