JP2842231B2 - Pretreatment of hot metal by bottom-blown gas stirring - Google Patents
Pretreatment of hot metal by bottom-blown gas stirringInfo
- Publication number
- JP2842231B2 JP2842231B2 JP6177511A JP17751194A JP2842231B2 JP 2842231 B2 JP2842231 B2 JP 2842231B2 JP 6177511 A JP6177511 A JP 6177511A JP 17751194 A JP17751194 A JP 17751194A JP 2842231 B2 JP2842231 B2 JP 2842231B2
- Authority
- JP
- Japan
- Prior art keywords
- hot metal
- gas
- stirring
- pretreatment
- blown
- 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
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/122—Reduction of greenhouse gas [GHG] emissions by capturing or storing CO2
Description
【０００１】[0001]
【産業上の利用分野】この発明は、転炉等の底吹き撹拌
機構を有する精錬容器による溶銑予備処理のためのガス
撹拌を安価に効率よく行う予備処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment method for inexpensively and efficiently performing gas stirring for pretreatment of hot metal in a smelting vessel having a bottom-blowing stirring mechanism such as a converter.
【０００２】[0002]
【従来の技術】高炉からの溶銑は、高炉の装入原料や操
業条件によって成分にかなりの変動が認められ、必ずし
も次の製鋼過程に適した成分組成であるとは限らない。
製鋼段階で要求される溶銑の成分組成は、最終の溶鋼の
目標成分組成や処理工程、生産能率などによって異なっ
てくる。そこで溶銑の成分組成、製鋼精錬方式、生産鋼
種などに応じて適宜に溶銑の予備処理を行う必要があ
る。特に、最近の傾向としては、低い燐含有量の高級鋼
が要求されている。2. Description of the Related Art The composition of molten iron from a blast furnace varies considerably depending on the raw material charged into the blast furnace and operating conditions, and is not always a composition suitable for the next steelmaking process.
The component composition of the hot metal required in the steelmaking stage differs depending on the target component composition of the final molten steel, the treatment process, the production efficiency, and the like. Therefore, it is necessary to appropriately perform pretreatment of the hot metal according to the component composition of the hot metal, the steelmaking refining method, the type of the produced steel, and the like. In particular, a recent trend is that high-grade steel with a low phosphorus content is required.
【０００３】溶銑の脱燐予備処理方法としては、容器内
の溶銑に、生石灰１５〜５０％、酸化鉄５０〜８５％、
蛍石０〜１０％からなる脱燐剤を、前記溶銑トン当たり
３０〜２２０ｋｇ添加し、インペラもしくは不活性ガス
吹き込みによる撹拌を与えつつ、溶銑温度を１２００〜
１４００℃に維持するに足る量の酸素を該溶銑中に吹き
込む方法（特開昭５４−１２２１号公報）、酸素上吹き
製鋼法において、酸素上吹きによる吹錬操作の期間中も
しくは引き続き吹錬終了後の排出期間まで、浴面下に二
酸化炭素（以下ＣＯ2という）および・もしくは一酸化
炭素（以下ＣＯという）を主とするガスを吹き込む方法
（特開昭５５−１５８２０８号公報）、反応容器として
上底吹き転炉を用い、溶銑に塊状の転炉スラグ系フラッ
クスを投入し、炉底ＣＯ2撹拌を行いながら上吹きラン
スを用いて少量の酸素を上吹きする方法（鉄と鋼 第７
６年（１９９０）第１１号）等が提案されている。[0003] As a pretreatment method for dephosphorization of hot metal, hot metal in a vessel is supplied with 15 to 50% of quick lime, 50 to 85% of iron oxide,
A dephosphorizing agent consisting of 0 to 10% of fluorite is added in an amount of 30 to 220 kg per ton of the hot metal, and the hot metal temperature is set to 1200 to 200 while stirring by impeller or inert gas injection.
A method in which an amount of oxygen sufficient to maintain the temperature at 1400 ° C. is blown into the hot metal (Japanese Patent Laid-Open No. 54-1221). In the oxygen top blowing steelmaking method, during or after the blowing operation by oxygen top blowing. A method in which a gas mainly containing carbon dioxide (hereinafter referred to as CO 2 ) and / or carbon monoxide (hereinafter referred to as CO) is blown under the bath surface until a later discharge period (Japanese Patent Application Laid-Open No. 55-158208), Using a top-blowing converter as a method, throwing a massive converter slag-based flux into the hot metal, and blowing a small amount of oxygen upward using a top-blowing lance while stirring the bottom CO 2 (iron and steel No. 7).
No. 11 of 1990 (1990)).
【０００４】上記転炉等の底吹き撹拌機構を有する精錬
容器を用いた溶銑の脱燐予備処理は、脱燐平衡に有利な
低温でのスラグ−メタル反応を促進させるため、十分な
ガス撹拌力が必要とされている。そのため、従来のガス
撹拌力を十分に得るには、底吹きガス流量を増量する
か、底吹きガスとして反応性の高いガスを使用すること
が広く行われている。一般に使用されているガスのう
ち、大量に吹き込むことを前提とすると、吹き込みガス
コストの観点から、底吹きガス流量の増量には、窒素ガ
ス（以下Ｎ2という）の大量吹き込み、反応性の高いガ
スの大量使用では、ＣＯ2の吹き込みが一般的である。[0004] Preliminary treatment of dephosphorization of hot metal using a refining vessel having a bottom-blown stirring mechanism such as the converter described above requires a sufficient gas stirring power to promote a slag-metal reaction at a low temperature which is advantageous for dephosphorization equilibrium. Is needed. Therefore, in order to sufficiently obtain the conventional gas stirring power, it is widely practiced to increase the flow rate of the bottom blown gas or to use a highly reactive gas as the bottom blown gas. Assuming that a large amount of commonly used gas is blown, from the viewpoint of the blown gas cost, an increase in the flow rate of the bottom blown gas requires a large amount of nitrogen gas (hereinafter, referred to as N 2 ) blown and a high reactivity. In large-volume use of gas, blowing of CO 2 is common.
【０００５】[0005]
【発明が解決しようとする課題】上記溶銑のガス撹拌力
を十分に得るため安価なＮ2を大量に吹き込む場合は、
吹き込み羽口の大径化が必要となり、実験の結果、羽口
寿命の低下を招くことが確認されている。また、底吹き
ガスとして反応性の高いガスを大量に吹き込む場合は、
撹拌用ガスコストの上昇を招き、その分不利となる。[SUMMARY OF THE INVENTION When blowing a large amount of inexpensive N 2 to obtain a sufficient gas agitation force of the molten iron,
It is necessary to increase the diameter of the blowing tuyere, and as a result of experiments, it has been confirmed that the life of the tuyere is reduced. Also, when blowing a large amount of highly reactive gas as the bottom blow gas,
This raises the cost of stirring gas, which is disadvantageous.
【０００６】この発明の目的は、転炉等の底吹き撹拌機
構を有する精錬容器を用いた溶銑の脱燐予備処理におい
て、底吹きガス吹き込み羽口寿命の低下を招くことな
く、撹拌用ガスコストを上昇させることなく、十分なガ
ス撹拌力を得ることができる底吹きガス撹拌による溶銑
の予備処理方法を提供することにある。SUMMARY OF THE INVENTION It is an object of the present invention to provide a pretreatment for dephosphorization of hot metal using a refining vessel having a bottom-blowing stirring mechanism such as a converter, without lowering the life of the bottom-blown gas blowing tuyere and reducing the cost of stirring gas. It is an object of the present invention to provide a method for pre-treating hot metal by bottom-blown gas agitation that can obtain a sufficient gas agitation force without raising the temperature.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、上記目的
を達成すべく種々試験研究を重ねた。その結果、溶銑の
脱珪脱燐予備処理は、図１に示すとおり脱珪期と脱燐期
に区分して整理できること、ＣＯ2などの反応性ガスを
底吹きする場合、Ｓｉ含有率の高い脱珪期においてＣＯ
2は、溶銑中の［Ｓｉ］と下記（１）式に示す脱珪反応
を起こすが体積の増加がない。しかし、Ｃ含有率が高
く、Ｓｉ含有率の低い脱燐期においては、ＣＯ2が溶銑
中の［Ｃ］と下記（２）式に示す脱炭反応によって２倍
量に体積が増すため、撹拌力が大幅に向上する。 ２ＣＯ2＋［Ｓｉ］→２ＣＯ＋（ＳｉＯ2）………………………………（１ ）式 １ＣＯ2＋［Ｃ］→２ＣＯ……………………………………… （２） 式 また、上記（１）式の反応は、発熱反応であるため、羽
口出口で優先的に反応すると、反応熱によってＣＯ2に
よる羽口冷却効果が低下し、反応熱を発しないＮ2の冷
却効果に劣り、羽口保護のためのマッシュルームの形成
が阻害されること、したがって、脱珪期においては、安
価なＮ2を使用することによって、安価に同じ撹拌力が
得られると共に、羽口の溶損が抑制されて寿命を延長で
きる。さらに、脱燐期においては、ＣＯ2などの反応性
ガスを使用することによって、上記（２）式の脱炭反応
により撹拌力の向上を図ることができると共に、前記
（１）式の発熱反応が起きないため、羽口への冷却効果
が向上して羽口寿命を延長できることを究明し、この発
明に到達した。Means for Solving the Problems The present inventors have conducted various tests and studies to achieve the above object. As a result, the desiliconization and dephosphorization pretreatment of the hot metal can be divided into a desiliconization period and a dephosphorization period as shown in FIG. 1, and when the reactive gas such as CO 2 is bottom-blown, the Si content is high. CO during desiliconization
2, [Si] and the following (1) causing desiliconizing reaction but there is no increase in volume in the expression of the molten iron. However, in the dephosphorization period in which the C content is high and the Si content is low, the volume of CO 2 is doubled by the decarburization reaction represented by the following formula (2) with [C] in the hot metal, so that stirring is performed. Power is greatly improved. 2CO 2 + [Si] → 2CO + (SiO 2 ) ········· (1) Formula 1CO 2 + [C] → 2CO ·························· ... (2) Equation Since the reaction of the above equation (1) is an exothermic reaction, if the reaction occurs preferentially at the tuyere outlet, the reaction heat reduces the tuyere cooling effect by CO 2 and generates reaction heat. Inferior in cooling effect of N 2 , formation of mushroom for tuyere protection is hindered. Therefore, in the desiliconization period, the same stirring power can be obtained at low cost by using inexpensive N 2. At the same time, the erosion of the tuyere is suppressed and the life can be extended. Further, in the dephosphorization period, by using a reactive gas such as CO 2 , the stirring power can be improved by the decarburization reaction of the above formula (2), and the exothermic reaction of the above formula (1) can be achieved. Since the generation of the tuyere does not occur, it has been found that the cooling effect on the tuyere can be improved and the life of the tuyere can be extended.
【０００８】すなわちこの発明は、底吹き撹拌機構を有
する精錬容器を用いて高炉溶銑を脱珪、脱燐処理する溶
銑の予備処理方法において、脱珪期における撹拌用ガス
としてＮ2を使用し、脱燐期における撹拌用ガスとして
ＣＯ2を使用することを特徴とする底吹きガス撹拌によ
る溶銑の予備処理方法である。That is, the present invention provides a pretreatment method of hot metal for desiliconizing and dephosphorizing blast furnace hot metal using a refining vessel having a bottom-blowing stirring mechanism, wherein N 2 is used as a stirring gas in the desiliconization period, This is a pretreatment method for hot metal by bottom-blown gas stirring, wherein CO 2 is used as a stirring gas in the dephosphorization period.
【０００９】[0009]
【作用】この発明においては、底吹き撹拌機構を有する
精錬容器を用いて高炉溶銑を脱珪、脱燐処理する溶銑の
予備処理の脱珪期における撹拌用ガスとしてＮ2を使用
するから、上記（１）式の発熱反応が優先的に起こった
としても、吹き込みＮ2によって冷却され、羽口保護の
ためのマッシュルームが形成されるため、安価に同じ撹
拌力が得られるると共に、羽口寿命を延長できる。ま
た、脱燐期における撹拌用ガスとしてＣＯ2を使用する
ことによって、上記（２）式の反応により撹拌力の向上
を図ることができると共に、前記（１）式の反応が起き
ないため、羽口への冷却効果が向上して羽口寿命を延長
できると共に、全体として底吹きガスコストを低減する
ことができる。In the present invention, N 2 is used as a stirring gas in the desiliconization stage of the pretreatment of hot metal for desiliconizing and dephosphorizing blast furnace hot metal using a refining vessel having a bottom-blowing stirring mechanism. Even if the exothermic reaction of the formula (1) occurs preferentially, it is cooled by blowing N 2 to form a mushroom for tuyere protection, so that the same stirring power can be obtained at low cost and the tuyere life Can be extended. Further, by using CO 2 as the stirring gas in the dephosphorization period, the stirring power can be improved by the reaction of the above formula (2), and the reaction of the above formula (1) does not occur. The effect of cooling the mouth is improved, the life of the tuyere can be extended, and the cost of bottom-blown gas can be reduced as a whole.
【００１０】この発明における溶銑予備処理での脱珪期
のＮ2底吹きから脱燐期のＣＯ2底吹きへの切替え時期
は、高炉溶銑成分中のＳｉ含有率より設定することがで
きる。また、脱燐期の底吹きガスとして用いる反応性ガ
スとしては、ＣＯ2を用いるのが一般的である。In the present invention, the timing of switching from the N 2 bottom blow during the desiliconization period to the CO 2 bottom blow during the dephosphorization period in the hot metal pretreatment can be set based on the Si content in the hot metal components of the blast furnace. In addition, CO 2 is generally used as a reactive gas used as a bottom blow gas in the dephosphorization stage.
【００１１】[0011]
実施例１ １６０Ｔｏｎ／チャージの上底吹き転炉を精錬容器とし
て使用し、表１に示す初期成分の溶銑に対し、脱燐剤と
して生石灰１０〜２５ｋｇ／Ｔｏｎと蛍石６．５〜７．
７ｋｇ／Ｔｏｎを添加し、塩基度（ＣａＯ／ＳｉＯ2）
２．３〜２．６となし、転炉内温度１３２５〜１３６５
℃に保持し、上吹きランスより酸素ガスを少量吹き付け
ながら、脱珪期に底吹きガスとして溶銑トン当たりＮ2
を０．１０Ｎｍ3／ｍｉｎで５分間吹き込み、その後溶
銑トン当たりＣＯ2を０．１０Ｎｍ3／ｍｉｎで５分間吹
き込んで脱珪、脱燐処理したのち、出鋼までの３分間溶
銑トン当たりＮ2を０．１０Ｎｍ3／ｍｉｎで吹き込んで
予備処理した。また、比較のため、脱珪期ならびに脱燐
期の底吹きガスとして溶銑トン当たりＣＯ2を０．１０
Ｎｍ3／ｍｉｎで１０分間吹き込んで脱珪、脱燐処理し
たのち、３分間溶銑トン当たりＮ2を０．１０Ｎｍ3／ｍ
ｉｎで吹き込んで予備処理した。各予備処理における実
塩基度とスラグ中への燐（Ｐ）と溶銑中への燐［Ｐ］の
分配率を調査した。その結果を図２に示す。また、上記
予備処理における底吹きガス吹き込み羽口の溶損速度指
数を測定した。その結果を底吹きガスとしてＣＯ2のみ
を吹き込んだ場合を１００として図３に示すExample 1 A 160-ton / charge top-bottom-blowing converter was used as a refining vessel, and 10-25 kg / ton of quicklime and 6.5-7.5 fluorite were used as dephosphorizing agents for the hot metal of the initial components shown in Table 1.
7 kg / Ton was added, and the basicity (CaO / SiO 2 )
2.3 to 2.6, converter temperature 1325 to 1365
° C, and while blowing a small amount of oxygen gas from the top blowing lance, N 2
Is blown at 0.10 Nm 3 / min for 5 minutes, then CO 2 is blown at 0.10 Nm 3 / min for 5 minutes to desiliconize and dephosphorize, and then N 2 per ton of hot metal for 3 minutes until tapping. Was blown at 0.10 Nm 3 / min to perform a preliminary treatment. For comparison, CO 2 per ton of hot metal was 0.10 as a bottom-blown gas during the desiliconization and dephosphorization phases.
After desiliconization and dephosphorization by blowing at Nm 3 / min for 10 minutes, N 2 was 0.10 Nm 3 / m per ton of hot metal for 3 minutes.
Pretreatment was performed by blowing in. The actual basicity and the distribution ratio of phosphorus (P) in slag and phosphorus [P] in hot metal in each pretreatment were investigated. The result is shown in FIG. Further, the melting rate index of the bottom-blown gas injection tuyere in the above pretreatment was measured. Figure 3 shows the case where blown into only CO 2 the result as a bottom-blown gas 100
【００１２】[0012]
【表１】 [Table 1]
【００１３】図２に示すとおり、脱珪期にＮ2、脱燐期
にＣＯ2を底吹きガスとして用いたＡの場合の脱燐特性
は、底吹きガスとして脱珪期ならびに脱燐期にＣＯ2を
用いたＢの場合とほぼ同等であった。また、図３に示す
とおり、羽口溶損速度指数は、底吹きガスとして脱珪期
ならびに脱燐期にＣＯ2を用いた場合を１００とすれ
ば、脱珪期にＮ2、脱燐期にＣＯ2を底吹きガスとして用
いた場合７５まで低減しており、その分羽口寿命を延長
することができる。As shown in FIG. 2, the dephosphorization characteristics in the case of A using N 2 during the desiliconization period and CO 2 as the bottom blow gas during the dephosphorization period are as follows. It was almost equivalent to the case of B using CO 2 . Further, as shown in FIG. 3, the tuyere erosion rate index, if the case of using CO 2 in de珪期and dephosphorization stage as bottom-blown gas and 100, N 2 in de珪期, Datsurinki In the case where CO 2 is used as the bottom-blown gas, the amount is reduced to 75, and the tuyere life can be extended accordingly.
【００１４】[0014]
【発明の効果】以上述べたとおり、この発明方法によれ
ば、脱珪・脱燐予備処理において、溶銑の底吹きガスに
よる撹拌能力の低下なしにガスコストを低減できると共
に、羽口冷却能力の向上により羽口寿命を延長すること
ができ、脱珪・脱燐予備処理コストを低減することがで
きる。As described above, according to the method of the present invention, in the pretreatment for desiliconization and dephosphorization, the gas cost can be reduced without lowering the stirring ability due to the bottom blown gas of the hot metal, and the tuyere cooling capacity can be reduced. The improvement can extend the tuyere life and reduce the cost of desiliconization and dephosphorization pretreatment.
【図１】溶銑の脱珪・脱燐予備処理における底吹き時間
と溶銑中のＳｉ、Ｐ含有率の変化を示す模式図である。FIG. 1 is a schematic diagram showing a bottom blowing time and a change in Si and P contents in hot metal in a pretreatment for desiliconization and dephosphorization of hot metal.
【図２】実施例における実塩基度と溶銑中の［Ｐ］に対
するスラグ中の（Ｐ）の対数割合を示すグラフである。FIG. 2 is a graph showing the actual basicity and the logarithmic ratio of (P) in slag to [P] in hot metal in an example.
【図３】実施例における底吹きガス種類と羽口溶損速度
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 type of bottom blown gas and the tuyere erosion rate index in Examples.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) C21C 1/04 101 C21C 1/02 110──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 6 , DB name) C21C 1/04 101 C21C 1/02 110
Claims (1)
て高炉溶銑を脱珪、脱燐処理する溶銑の予備処理方法に
おいて、脱珪期における撹拌用ガスとして窒素ガスを使
用し、脱燐期における撹拌用ガスとして二酸化炭素ガス
を使用することを特徴とする底吹きガス撹拌による溶銑
の予備処理方法。In a pretreatment method of hot metal for desiliconizing and dephosphorizing blast furnace hot metal using a refining vessel having a bottom blow stirring mechanism, nitrogen gas is used as a stirring gas in the desiliconization period, A method for pre-treating hot metal by bottom-blown gas stirring, wherein carbon dioxide gas is used as a stirring gas in the method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6177511A JP2842231B2 (en) | 1994-07-05 | 1994-07-05 | Pretreatment of hot metal by bottom-blown gas stirring |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6177511A JP2842231B2 (en) | 1994-07-05 | 1994-07-05 | Pretreatment of hot metal by bottom-blown gas stirring |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0820810A JPH0820810A (en) | 1996-01-23 |
| JP2842231B2 true JP2842231B2 (en) | 1998-12-24 |
Family
ID=16032189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6177511A Expired - Lifetime JP2842231B2 (en) | 1994-07-05 | 1994-07-05 | Pretreatment of hot metal by bottom-blown gas stirring |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2842231B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114959157B (en) * | 2022-04-22 | 2024-04-09 | 中国恩菲工程技术有限公司 | Method and device for producing low-phosphorus molten iron from high-phosphorus reduced iron |
-
1994
- 1994-07-05 JP JP6177511A patent/JP2842231B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0820810A (en) | 1996-01-23 |
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