JPH0420962B2 - - Google Patents
Info
- Publication number
- JPH0420962B2 JPH0420962B2 JP4286486A JP4286486A JPH0420962B2 JP H0420962 B2 JPH0420962 B2 JP H0420962B2 JP 4286486 A JP4286486 A JP 4286486A JP 4286486 A JP4286486 A JP 4286486A JP H0420962 B2 JPH0420962 B2 JP H0420962B2
- Authority
- JP
- Japan
- Prior art keywords
- hot metal
- gutter
- slag
- refining
- nozzles
- 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
Links
- 239000002184 metal Substances 0.000 claims description 40
- 238000007670 refining Methods 0.000 claims description 24
- 238000002203 pretreatment Methods 0.000 claims description 7
- 239000002893 slag Substances 0.000 description 19
- 239000003795 chemical substances by application Substances 0.000 description 14
- 238000000034 method Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 7
- 239000011819 refractory material Substances 0.000 description 7
- 238000007664 blowing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000003628 erosive effect Effects 0.000 description 5
- 238000005422 blasting Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000012159 carrier gas Substances 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011823 monolithic refractory Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
〔産業上の利用分野〕
本発明は、高炉樋中に流れる溶銑に精錬材を添
加して予備精錬を行なう溶銑予備処理方法に関す
る。
〔従来の技術〕
近年、鋼成分に対する要求が厳しくなる(低P.
S.鋼化)に従い、溶銑予備処理の必要性、重要性
が高まり、更に工程省略、簡易処理等の有利さも
あつて、特に高炉樋中における精錬剤の添加処理
による溶銑予備処理が盛んに行なわれるようにな
つてきた。溶銑中に精錬剤を添加する方法は、上
置き法、インジエクシヨン法、ブラステイング法
に大きく分ける事ができる。このうち、精錬剤の
添加混合の面より考えると、浸漬ランスよりのイ
ンジエクシヨン法が最も優れている。しかし、ラ
ンスの侵食によるランニングコストを考えると、
最近は特開昭58−130208号公報にみられるように
溶銑上面より、高速流により精錬剤を吹込むブラ
ステイング法が多く採用されるに至つている。
ところが、この予備処理には従来無かつたよう
な問題が起きている。すなわち、予備処理を行な
わない従来の製鋼法では、高炉樋中を流れるスラ
グがSiO2やCaOといつたようなものを主成分と
していたため、樋耐火物に極めて安定的に作用
し、樋耐火物の寿命を延ばしてきた。ところが溶
銑予備処理が行なわれるようになると、生成スラ
グ中にFeOを主とする耐火物にとつて極めて有害
な成分が混入し、それによる侵食が一つの問題と
なつて現われてきた。樋耐火物の侵食は溶銑とス
ラグとの境界が接する位置で最も激しく、しかも
溶銑流量による溶銑面変動がわずかしかなく略一
定(約20〜30mmの範囲程度)のため、樋寿命を一
層短命にするのに迫車をかけていた。
この解決策として従来は、樋耐火物の材質を種
種のものに替えたり、特開昭57−134505号公報に
みられるように樋側壁により保護ガスを吹き込
み、スラグを樋中央によせることを提案してい
る。
〔発明が解決しようとする問題点〕
しかし、前者の場合は、溶銑予備処理の内容に
合わせて材質を選ぶ必要があり、その選定も難し
く、予備処理の内容が変わる毎に材質を変えるこ
とは操業上からしても困難である。又材質の高級
化を伴うことにもなるので、耐火物原単位(溶銑
処理量当りの耐火物費用)が悪化するという問題
もある。
後者の場合は、保護ガスにより溶銑温度が低下
し、又樋旋行時の作業性の難しさから実用的には
問題がある。
そこで、本発明者が種々研究した結果、ブラス
テイング法には溶銑面上の波立ちが多く、耐火物
の侵食も厳しいという欠点があるものの、それら
の欠点は精錬剤が溶銑上面よりスラグを突抜ける
際にスラグに与える大きな力や吹込み方向調整で
解決できることを見出し、ここに耐侵食性を向上
させた溶銑連続予備処理方法を提供するものであ
る。
〔問題点を解決するための手段〕
本発明は、鋭意研究の結果、溶銑を連続的に流
し導く樋中に、精錬剤を添加する溶銑連続予備処
理方法において、複数のノズルを溶銑流れ方向に
並べると共に各ノズルの先端を樋壁面側より中央
部に向けて配置し、その複数のノズルを介して精
錬剤を溶銑上面より高速で溶銑中に吹き込むよう
にしたことを特徴とする。
複数のノズルは、スプラツシユを低減させ、ス
ラグ層に樋中央寄りの力を与えるために、第2
図、及び第3図にみられるように溶銑流れ方向に
沿つて0°α45°、特に5°α30°の角度が好
ましく、また、溶銑横断面方向に沿つて0°<θ<
4.5°の角度で傾けることが望しい。吹込み角度
α、θ共に溶銑流速を加味して、吹込み精錬剤の
浮上点が樋中央となるように調整するのがよく、
その上限は45°で、これ以上傾けると吹込み精錬
剤が溶銑中に進入しにくくなり、スプラツシユ増
加と伴に大幅な精錬反応効率低下となる。更に各
ノズルを千鳥に配置することにより一層その効果
が大きい。
精錬材のキヤリアガスとしては、N2等の不活
性ガスのほか、圧空または酸素等の支燃ガス等を
用いることができる。キヤリアガスの吹き込み圧
力は溶銑の深さやノズル口経により一概には定め
られないがスラグ層に樋中央寄りの力を与え、か
つ撹拌を十分行ないうるために1.5〜6Kgf/cm2
程度にすることが望しい。
〔作用〕
精錬材の吹き込みにより、スラグ層に樋中央寄
りの力が生じ、スラグ層が樋壁面を離れて中央に
集まり流れるので樋耐火物の侵食を軽減できる。
〔実施例〕
以下、図面を参照して実施例を説明する。
第1図は本発明の実施に用いられる装置の概略
図で、図中、1は耐火物で構築された高炉樋であ
る。耐火物には、Al2O3:80wt%、SiC+C:
15wt%の不定形耐火物、その他の耐火物を用い
ることができる。
高炉樋1の上流側にはスキンマー2が配置さ
れ、その下流側の樋壁面にはスラグ排出口1aが
設けられている。スキンマー2とスラグ排出口1
aとの間には、予備精錬を行うために精錬剤を溶
銑3面に吹き付ける複数のノズル4…が溶銑3面
上に配置されている。複数のノズル4…は溶銑流
れ方向(矢印)に、二列並べられており、各ノズ
ル4…の先端は樋1壁面側より中央部に向けて配
向されている。具体的にはノズル4…の傾角をα
=15°、θ=10°にとり、各ノズル4…を千鳥に配
置している。なお、5は精錬剤を入れるタンクで
ある。
このような装置を用いて、溶銑10Ton/minに
対し、脱燐を行つた。精錬剤はCaO:40wt%、
CaF:8wt%、ミルスケール:50wt%から成るも
のである。この精錬剤をキヤリアガスを用いて、
圧力400Kg/minで吹込んだ。
この吹込みで十分な撹拌が行なわれ、スラグ6
が樋1壁面より離れて中央よりを進み、スラグ排
出口1aより排出された。
効果を比較するため、同条件下で、樋精錬を行
ない、耐火物の溶銑面の接する位置での侵食量を
測定したところ、下記第1表の如く結果を得た。
[Industrial Application Field] The present invention relates to a hot metal pretreatment method in which a refining material is added to hot metal flowing in a blast furnace gutter to perform preliminary refining. [Conventional technology] In recent years, requirements for steel composition have become stricter (low P.
S. steelmaking), the necessity and importance of pre-treatment of hot metal has increased, and due to the advantages of omitting processes and simple processing, pre-treatment of hot metal by adding refining agents in the blast furnace trough has been actively carried out. I'm starting to be able to do it. Methods for adding refining agents into hot metal can be broadly divided into the overlay method, the injection method, and the blasting method. Among these methods, the injection method using an immersion lance is the most superior in terms of addition and mixing of refining agents. However, considering the running cost due to lance erosion,
Recently, the blasting method, in which a refining agent is injected into the top of the hot metal using a high-speed flow, has come into widespread use, as shown in Japanese Patent Application Laid-Open No. 58-130208. However, this preliminary processing presents a problem that has not existed in the past. In other words, in the conventional steelmaking method that does not perform pretreatment, the slag flowing in the blast furnace gutter has SiO 2 and CaO as its main components, which acts extremely stably on the gutter refractories, making the gutter refractory It has extended the lifespan of things. However, when pre-treatment of hot metal began to be carried out, components that were extremely harmful to refractories, mainly FeO, were mixed into the produced slag, and corrosion caused by this became a problem. Erosion of the gutter refractory is most severe at the point where the boundary between the hot metal and slag meets, and the molten metal surface changes only slightly due to the flow rate of the hot metal and is almost constant (approximately in the range of 20 to 30 mm), making the life of the gutter even shorter. A mortar was applied to the vehicle. As a solution to this problem, conventional proposals have been to change the material of the gutter refractory to a different type, or to blow protective gas through the side walls of the gutter to direct the slag to the center of the gutter, as seen in Japanese Patent Application Laid-Open No. 57-134505. are doing. [Problem to be solved by the invention] However, in the former case, it is necessary to select the material according to the content of the hot metal pretreatment, and the selection is difficult, and it is difficult to change the material every time the content of the pretreatment changes. This is also difficult from an operational standpoint. In addition, since the quality of the material becomes higher, there is also the problem that the refractory unit cost (refractory cost per amount of hot metal processed) deteriorates. In the latter case, there is a practical problem because the protective gas lowers the temperature of the hot metal and it is difficult to work when turning the gutter. As a result of various studies conducted by the present inventor, the blasting method has disadvantages in that there are many ripples on the surface of the hot metal and severe erosion of the refractory, but these disadvantages are due to the fact that the refining agent penetrates the slag from the top surface of the hot metal. We have discovered that this can be solved by applying a large force to the slag and adjusting the blowing direction, and hereby provide a method for continuous pretreatment of hot metal with improved corrosion resistance. [Means for Solving the Problems] As a result of extensive research, the present invention has developed a continuous pretreatment method for hot metal in which a refining agent is added to a gutter that continuously flows and guides hot metal. They are arranged side by side and the tip of each nozzle is arranged toward the center from the gutter wall side, and the refining agent is blown into the hot metal from the upper surface of the hot metal at high speed through the plurality of nozzles. The multiple nozzles have a second nozzle to reduce splash and apply force to the slag layer toward the center of the gutter.
As shown in Fig. 3 and Fig. 3, an angle of 0°α45°, especially 5°α30° along the hot metal flow direction is preferred, and an angle of 0°<θ< along the cross-sectional direction of the hot metal is preferred.
It is preferable to tilt it at an angle of 4.5°. It is best to adjust the blowing angles α and θ so that the floating point of the blown refining agent is at the center of the gutter, taking into account the flow rate of hot metal.
The upper limit is 45°; if the tilt angle is greater than this, it becomes difficult for the blown refining agent to enter the hot metal, resulting in an increase in splash and a significant drop in refining reaction efficiency. Furthermore, the effect is even greater by arranging the nozzles in a staggered manner. As the carrier gas for the refining material, in addition to an inert gas such as N 2 , compressed air or a combustion supporting gas such as oxygen can be used. The blowing pressure of the carrier gas cannot be determined unconditionally depending on the depth of the hot metal and the nozzle opening, but it is 1.5 to 6 Kgf/cm 2 in order to apply force to the slag layer toward the center of the gutter and to ensure sufficient stirring.
It is desirable to keep it to a certain extent. [Operation] By blowing the refining material, a force is generated in the slag layer toward the center of the gutter, and the slag layer leaves the gutter wall surface and gathers at the center and flows, reducing erosion of the gutter refractories. [Example] Hereinafter, an example will be described with reference to the drawings. FIG. 1 is a schematic diagram of an apparatus used for carrying out the present invention, and in the figure, 1 is a blast furnace gutter constructed of refractory material. Refractories include Al 2 O 3 : 80wt%, SiC+C:
15wt% monolithic refractories and other refractories can be used. A skimmer 2 is arranged on the upstream side of the blast furnace gutter 1, and a slag discharge port 1a is provided on the gutter wall surface on the downstream side. Skinmer 2 and slag outlet 1
A plurality of nozzles 4 are arranged on the three surfaces of the hot metal for spraying a refining agent onto the three surfaces of the hot metal in order to perform preliminary refining. The plurality of nozzles 4 are arranged in two rows in the hot metal flow direction (arrow), and the tip of each nozzle 4 is oriented from the wall side of the gutter 1 toward the center. Specifically, the inclination angle of nozzle 4 is α
= 15° and θ = 10°, and the nozzles 4 are arranged in a staggered manner. Note that 5 is a tank in which the refining agent is placed. Using such equipment, 10 tons/min of hot metal was dephosphorized. Refining agent is CaO: 40wt%,
It consists of CaF: 8wt% and mill scale: 50wt%. Using a carrier gas, this refining agent is
It was blown at a pressure of 400Kg/min. Sufficient agitation is achieved by this blowing, and the slag 6
The slag moved away from the wall of the gutter 1 and proceeded from the center, and was discharged from the slag discharge port 1a. In order to compare the effects, gutter refining was carried out under the same conditions and the amount of erosion at the position where the refractory was in contact with the hot metal surface was measured, and the results were obtained as shown in Table 1 below.
以上説明したように、本発明によれば次のよう
な効果を有する。
樋寿命を長くすることができる。
ブラステイングの次段との干渉が少なく、精
錬効率が高い。
壁面近くより吹込めるので、溶銑流の全断面
に渡つて撹拌できる。
スラグ層は中央部で厚く、壁面近くで薄いの
で、吹込み時の精錬剤のスラグ層による飛散が
少ない。
ノズル角度を調整することによりスプラツシ
ユを大幅に低減できる。
壁面保護ガスが不要である。
これらの効果は、耐火物侵食の激しい脱燐処理
に応用すると顕著に現われる。
As explained above, the present invention has the following effects. Gutter life can be extended. There is little interference with the next stage of blasting, and the refining efficiency is high. Since it can be blown in from near the wall, it can stir the entire cross section of the hot metal flow. The slag layer is thick in the center and thin near the wall, so there is less scattering of the refining agent by the slag layer during injection. Splash can be significantly reduced by adjusting the nozzle angle. No wall protection gas required. These effects become noticeable when applied to dephosphorization treatment that causes severe corrosion of refractories.
第1図は、本発明に用いられる装置の概略を示
した斜視図、第2図は溶銑流れ方向に沿つて並べ
られたノズルの正面図、第3図は溶銑横断面に沿
つて傾けられたノズルの側面図である。
1……高炉樋、1a……スラグ排出口、2……
スキンマー、3……溶銑、4……ノズル、5……
タンク、6……スラグ。
Fig. 1 is a perspective view showing the outline of the device used in the present invention, Fig. 2 is a front view of the nozzles arranged along the flow direction of hot metal, and Fig. 3 is a perspective view of the nozzles arranged along the hot metal flow direction. It is a side view of a nozzle. 1...Blast furnace gutter, 1a...Slag discharge port, 2...
Skinmer, 3...Hot metal, 4...Nozzle, 5...
Tank, 6...Slag.
Claims (1)
加する溶銑連続予備処理方法において、複数のノ
ズルを溶銑流れ方向に並べると共に各ノズルの先
端を樋壁面側より中央部に向けて配置し、その複
数のノズルを介して精錬剤を溶銑上面より高速で
溶銑中に吹き込むことを特徴とする溶銑連続予備
処理方法。1. In a hot metal continuous pretreatment method in which a refining agent is added to a gutter that continuously flows and guides hot metal, a plurality of nozzles are lined up in the hot metal flow direction, and the tip of each nozzle is arranged from the gutter wall side toward the center. , a continuous hot metal pretreatment method characterized by injecting a refining agent into the hot metal from the upper surface of the hot metal at high speed through the plurality of nozzles.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4286486A JPS62202009A (en) | 1986-02-28 | 1986-02-28 | Continuous and preliminary treatment of molten iron |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP4286486A JPS62202009A (en) | 1986-02-28 | 1986-02-28 | Continuous and preliminary treatment of molten iron |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS62202009A JPS62202009A (en) | 1987-09-05 |
JPH0420962B2 true JPH0420962B2 (en) | 1992-04-07 |
Family
ID=12647896
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP4286486A Granted JPS62202009A (en) | 1986-02-28 | 1986-02-28 | Continuous and preliminary treatment of molten iron |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS62202009A (en) |
-
1986
- 1986-02-28 JP JP4286486A patent/JPS62202009A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS62202009A (en) | 1987-09-05 |
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