JPH01142009A - Steel making method - Google Patents
Steel making methodInfo
- Publication number
- JPH01142009A JPH01142009A JP30126287A JP30126287A JPH01142009A JP H01142009 A JPH01142009 A JP H01142009A JP 30126287 A JP30126287 A JP 30126287A JP 30126287 A JP30126287 A JP 30126287A JP H01142009 A JPH01142009 A JP H01142009A
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- dephosphorization
- hot metal
- slag
- refining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000009628 steelmaking Methods 0.000 title claims abstract description 15
- 239000011572 manganese Substances 0.000 claims abstract description 97
- 239000002893 slag Substances 0.000 claims abstract description 71
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 52
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims abstract description 51
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 46
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000007670 refining Methods 0.000 claims abstract description 36
- 229910052742 iron Inorganic materials 0.000 claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 14
- 229910052751 metal Inorganic materials 0.000 claims description 61
- 239000002184 metal Substances 0.000 claims description 61
- 238000005261 decarburization Methods 0.000 claims description 45
- 238000007664 blowing Methods 0.000 claims description 32
- 230000008569 process Effects 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 10
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 8
- 229910001882 dioxygen Inorganic materials 0.000 claims description 8
- 238000003723 Smelting Methods 0.000 claims description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 abstract description 42
- 239000000292 calcium oxide Substances 0.000 abstract description 21
- 235000012255 calcium oxide Nutrition 0.000 abstract description 21
- 238000004519 manufacturing process Methods 0.000 abstract description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052760 oxygen Inorganic materials 0.000 abstract description 3
- 239000001301 oxygen Substances 0.000 abstract description 3
- 238000013019 agitation Methods 0.000 abstract description 2
- 229910000617 Mangalloy Inorganic materials 0.000 abstract 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 40
- 229910000831 Steel Inorganic materials 0.000 description 33
- 239000010959 steel Substances 0.000 description 33
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 13
- 239000010436 fluorite Substances 0.000 description 13
- 239000000203 mixture Substances 0.000 description 11
- 230000004907 flux Effects 0.000 description 10
- 229910052698 phosphorus Inorganic materials 0.000 description 9
- 239000011574 phosphorus Substances 0.000 description 9
- 239000000571 coke Substances 0.000 description 8
- 229910000805 Pig iron Inorganic materials 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000006477 desulfuration reaction Methods 0.000 description 7
- 230000023556 desulfurization Effects 0.000 description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 239000010459 dolomite Substances 0.000 description 4
- 229910000514 dolomite Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000007800 oxidant agent Substances 0.000 description 4
- 229910000616 Ferromanganese Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000005422 blasting Methods 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001341 Crude steel Inorganic materials 0.000 description 1
- 101100348017 Drosophila melanogaster Nazo gene Proteins 0.000 description 1
- 229910001021 Ferroalloy Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 150000002696 manganese Chemical class 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000012749 thinning agent Substances 0.000 description 1
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
【発明の詳細な説明】
〈産業上の利用分野〉
この発明は、全製鋼工程を通じての造滓剤（生石灰等）
使用量を極力抑えつつ高能率脱燐を行うと共に、精錬剤
としてマンガン鉱石（鉄−マンガン鉱石も含む）を利用
し、かつそれを最大限に溶融還元して転炉における精錬
終点［Ｍｎ］濃度を上昇させることにより、品質の良好
な綱をコスト安く溶製する方法に関するものである。[Detailed Description of the Invention] <Industrial Field of Application> The present invention is directed to the use of slag-forming agents (quicklime, etc.) throughout the entire steelmaking process.
In addition to performing highly efficient dephosphorization while minimizing the amount used, we also use manganese ore (including iron-manganese ore) as a refining agent and maximize the melting and reduction of it to reduce the [Mn] concentration at the end of refining in the converter. The present invention relates to a method for producing high-quality steel at a low cost by increasing the amount of steel.
〈背景技術〉
近年、低燐鋼をより一層低いコストで安定溶製する手段
の開発を目指して様々な研究がなされるようになったが
、このような状況の中で、最近では製鋼トータルコスト
のミニマム化や低燐鋼の安定溶製に関し次のような溶銑
の予備脱燐法、即ち、（ａ）トーピード内の溶銑に生石
灰系のフラックス又はソーダ灰をインジェクションする
ことで予備脱燐を行う方法。<Background technology> In recent years, various studies have been conducted with the aim of developing means to stably produce low-phosphorus steel at even lower costs. Regarding the minimization of phosphorus and the stable production of low phosphorus steel, the following preliminary dephosphorization method of hot metal is used: (a) Preliminary dephosphorization is carried out by injecting quicklime-based flux or soda ash into the hot metal in a torpedo. Method.
（ｂｌ 取鍋内の溶銑に生石灰系のフラックスをイン
ジェクションしたりブラスティング（吹き付け）するこ
とで予備脱燐を行う方法。(bl) A method of preliminary dephosphorization by injecting or blasting quicklime-based flux into hot metal in a ladle.
（Ｃ１高炉鋳床樋中の溶銑に生石灰系のフラックスをブ
ラスティングして予備脱燐を行う方法。(A method in which preliminary dephosphorization is performed by blasting quicklime-based flux to the hot metal in the C1 blast furnace casthouse gutter.
が提案され、一部実用化もなされるようになった。have been proposed, and some have even been put into practical use.
しかし、前記（ａ）及び中）の方法では脱燐を“脱燐剤
の浮上過程で進行する反応（トランジトリ−・リアクタ
ー・リアクション）″に幀るため脱燐フラックスの利用
効率が必ずしも良くなく、また処理時間が長くかかる分
だけ処理時の抜熱が大きくなって溶銑温度が低下すると
言う問題があり、−方、前記（Ｃ１の方法では脱燐処理
が高炉から出銑された直後の溶銑に施されることがら脱
燐処理温度が約１４００℃と高く、従って到達Ｐ含有量
が十分に満足できるレベルになり難いとの指摘がなされ
ていた。However, in methods (a) and (middle) above, the dephosphorization is limited to "reactions that proceed during the floating process of the dephosphorizing agent (transitary reactor reaction)," so the efficiency of using the dephosphorizing flux is not necessarily good. There is also the problem that the longer the treatment time, the more heat is removed during the treatment and the temperature of the hot metal decreases. It has been pointed out that since the dephosphorization treatment is carried out at a high temperature of about 1400° C., it is difficult to achieve a sufficiently satisfactory P content.
その上、溶銑脱燐フラックスとして生石灰等を用いる場
合には、その後の転炉吹錬で使用される生石灰等の量を
も合わせて考えると、前記何れの方法も、“予備脱燐工
程を省いて転炉のみでの脱燐を行う方法”に比べて必要
造滓剤量（生石灰等の量）の低減効果はそれほど顕著で
あるとは言えなかった。Furthermore, when using quicklime etc. as a hot metal dephosphorization flux, considering the amount of quicklime etc. used in the subsequent converter blowing, both of the above methods are effective in eliminating the preliminary dephosphorization step. It could not be said that the effect of reducing the required amount of slag forming agent (amount of quicklime, etc.) was not so remarkable compared to the method of dephosphorizing using only a converter.
そこで、上記状況を踏まえた本発明者等は、先に、第３
図で略示されるような［上下両吹き機能を有した２基の
転炉形式の炉を使用するとともに、そのうちの一方を脱
燐炉１、他方を脱炭炉２とし、前記脱燐炉１内へ注入し
た溶銑３に前記脱炭炉２で発生した転炉滓４を主成分と
する精錬剤の添加を行い、攪拌ガス吹き込みノズル５に
よる底吹きガス攪拌を実施しつつランス６より酸素ガス
を上吹きして脱燐炉１の溶銑３の温度を１４００℃以下
に保ちながら溶銑脱燐を行った後、得られた脱燐溶銑を
脱炭炉２にて脱炭並びに仕上脱燐することにより、極め
て少ない量の造滓剤でもって通常燐レベルの鋼或いは低
燐鋼を作業性良く低コストで製造し得るようにした製鋼
方法」
を確立し、特願昭６１−１３２５１７号として提案した
。Therefore, based on the above situation, the present inventors first decided to
As shown schematically in the figure, two converter-type furnaces having both upper and lower blowing functions are used, and one of them is used as a dephosphorization furnace 1, the other as a decarburization furnace 2, and the dephosphorization furnace 1 is used. A refining agent mainly composed of converter slag 4 generated in the decarburization furnace 2 is added to the hot metal 3 injected into the molten iron 3, and oxygen gas is added from the lance 6 while bottom blowing gas is stirred by the stirring gas blowing nozzle 5. After dephosphorizing the hot metal while keeping the temperature of the hot metal 3 in the dephosphorization furnace 1 below 1400 ° C. by top blowing, the obtained dephosphorized hot metal is decarburized and final dephosphorized in the decarburization furnace 2. Established a "steel manufacturing method that enables the production of normal phosphorus level steel or low phosphorus steel with good workability and at low cost with an extremely small amount of slag forming agent" and proposed it as patent application No. 132517/1982. .
なお、本発明者等が先に提案した上記発明は、［全製鋼
工程を通じての造滓剤の必要量はスラグとメタルとを向
流的に接触させる“スラグ−メタル向流精錬”によると
きが最も少なくて良いが、実際上は該向流精錬の完全な
実現は殆ど不可能であり、現状において最も労少なべ造
薄剤の使用量を抑え得る可能性を秘めた製鋼手□段とし
て挙げ得るものは、脱燐工程を２段階に分餉し、その下
工程で発生するスラグを上土程の脱燐剤と”して使用す
る方法以外に見当たらない」との認識の下に、該“転炉
滓再利用による製鋼法”に藺じ、作業安定性、脱燐効率
或いは設備コスト等の面での問題点解消を目指した研究
による次の知見事項′（Ａ）〜（Ｆ）、即ち、
（＾）溶銑の脱燐処理においては脱燐効率からみて処理
温度を出来るだけ低くする方が良いが、該温度が余りに
低くなり過ぎると次工程での不都合を引き起こす上、処
理後スラグへの粒鉄ロスが多くなると言う問題が生じる
ので、該温度は１２００〜１４００℃、好ましくは１３
０〇〜１３５０℃程度が最も良好である。しかし、実際
作業では脱燐剤の添加そのものが処理温度を低下する大
きな要因となるので上記温度を保持するのは極めて困難
であるが、脱燐処理時に少量の酸素ガスを吹き込むこと
によって前記処理温度が安定かつ容易に維持される。In addition, the above-mentioned invention previously proposed by the present inventors states that [the required amount of slag forming agent throughout the entire steelmaking process is sometimes determined by "slag-metal countercurrent refining" in which slag and metal are brought into contact with each other in a countercurrent manner. The least amount is fine, but in reality it is almost impossible to fully realize countercurrent refining, and it is currently listed as the steelmaking method with the least amount of labor and the potential to reduce the amount of thinning agent used. Recognizing that the only way to achieve this goal is to divide the dephosphorization process into two stages and use the slag generated in the lower process as a dephosphorizing agent. The following findings from research aimed at resolving problems in terms of work stability, dephosphorization efficiency, equipment cost, etc. based on the "steel manufacturing method by reusing converter slag" (A) to (F), In other words, (^) In the dephosphorization treatment of hot metal, it is better to keep the treatment temperature as low as possible from the viewpoint of dephosphorization efficiency, but if the temperature becomes too low, it will not only cause problems in the next process, but also cause problems in the slag after treatment. The temperature is 1,200 to 1,400°C, preferably 13
The best temperature is about 0~1350°C. However, in actual work, it is extremely difficult to maintain the above temperature because the addition of the dephosphorizing agent itself is a major factor in lowering the processing temperature, but by blowing a small amount of oxygen gas during the dephosphorization process, is stable and easily maintained.
（ｉ３） フラックスの脱燐能を十分に発揮せしめて
脱燐能率を上げるには、上述のような処理温度の調整も
さることながら、脱燐平衡状態を達成するための十分な
攪拌を欠くことができないが、高温の溶銑を高能率脱燐
するに十分満足できる効率の良い攪拌を短時間に実現す
るためには、−処理容器底部から吹き込まれるガスによ
るガス攪拌が最も好ましい。(i3) In order to fully utilize the dephosphorizing ability of the flux and increase the dephosphorizing efficiency, it is necessary to adjust the treatment temperature as described above, as well as to lack sufficient stirring to achieve a dephosphorizing equilibrium state. However, in order to achieve sufficient and efficient stirring in a short time for highly efficient dephosphorization of high-temperature hot metal, gas stirring using gas blown from the bottom of the processing vessel is most preferable.
（Ｃ） 加えて、効率の良い脱燐処理を行うためには
処理容器にスラグフォーミングのための十分なフリーボ
ード（場面から容器上端までの距離）が必要である。(C) In addition, in order to perform an efficient dephosphorization process, the processing vessel must have sufficient freeboard (distance from the scene to the top of the vessel) for slag forming.
（Ｄ） スラグによる処理容器耐火物の溶損を軽減し
て脱燐作業能率を上げるためには、塩基性ライニングの
使用が好ましい。(D) In order to reduce erosion of the processing vessel refractories due to slag and increase dephosphorization work efficiency, it is preferable to use a basic lining.
（Ｅ）２段階脱燐工程を含む製鋼法において脱燐作業能
率を上げるためには処理容器からの排滓能率を無視する
ことができず、排滓が容易な処理容器の使用を欠かせな
い。(E) In order to increase the efficiency of dephosphorization in a steelmaking process that includes a two-stage dephosphorization process, the efficiency of removing slag from the processing container cannot be ignored, and it is essential to use a processing container that allows easy removal of slag. .
（Ｆ） 高品質鋼を作業性良く量産するためには十分
な排ガス処理設備（集塵＊＞が必要である。(F) In order to mass-produce high-quality steel with good workability, sufficient exhaust gas treatment equipment (dust collection*) is necessary.
（Ｇ） これらの条件を考慮すると、溶銑脱燐処理容
器としては転炉形式の炉、それも炉底から攪拌ガスを導
入できる上下両吹き機能を有した複合吹錬転炉が理想的
であり、これを使用して前述した“２段階脱燐工程を含
む製鋼法”を実施すると、全製鋼工程を通じての造滓剤
の使用量が極く少なくても十分に効率の良い脱燐がなさ
れ、高品質鋼を作業能率良く量産できる。(G) Considering these conditions, a converter-type furnace is ideal as a hot metal dephosphorization treatment vessel, especially a combined blowing converter that has both upper and lower blowing functions that can introduce stirring gas from the bottom of the furnace. When this is used to carry out the above-mentioned "steel manufacturing method including two-stage dephosphorization process", sufficiently efficient dephosphorization can be achieved even if the amount of slag forming agent used throughout the entire steel manufacturing process is extremely small. High-quality steel can be mass-produced with high efficiency.
を基に完成されたものである。It was completed based on.
そして、この本発明者等が先に提案した方法は、使用造
滓剤量を極力抑えた低コスト操業でもって低燐鋼を安定
して製造することができ、高品質鋼を安価に提供する上
で極めて有利であった。The method previously proposed by the present inventors can stably produce low-phosphorus steel with low-cost operation that minimizes the amount of slag-forming agent used, and provides high-quality steel at a low cost. It was extremely advantageous.
しかも、該提案は、転炉精錬（脱炭炉精錬）の際にＭｎ
鉱石を投入し、精錬時の［Ｍｎ］ ロスの軽減や溶鋼［
Ｍｎ］上昇を図ることをも示唆しており、高Ｍｎ鋼を溶
製する場合でも非常に有益なものであった。Moreover, this proposal requires Mn during converter refining (decarburization furnace refining).
Input ore to reduce [Mn] loss during refining and to reduce molten steel [
It also suggests that efforts should be made to increase Mn], which is extremely useful even when producing high-Mn steel.
特に、近年、厚板鋼材の品質安定化と低コスト化要求が
強まってきたことに対処し、高Ｍｎ鋼をできるだけ低い
価格で溶製しようとの研究が盛んに行われており、これ
らのうちの最も有効な手段として“転炉内の溶銑にマン
ガン鉱石を投入して酸素吹錬を行うことで終点［Ｍｎ］
？Ｆｊｓ度を上昇させる転炉精錬方法”が挙げられる
が、上記提案の方法によって造滓剤使用量の低減が可能
となり、このことによってマンガン鉱石投入による溶鋼
［Ｍｎ］上昇をより効果的に行うことが可能となったの
である。In particular, in recent years, in response to the increasing demand for quality stabilization and cost reduction of thick plate steel materials, research has been actively conducted to produce high-Mn steel at the lowest possible price. The most effective means of
? The method proposed above makes it possible to reduce the amount of slag-forming agent used, which makes it possible to more effectively increase the molten steel [Mn] by adding manganese ore. became possible.
ただ、上記提案の方法では、マンガン鉱石の添加を脱炭
炉で行うことを主眼とし、これによって脱炭炉終点の［
Ｍｎ］濃度を上昇させることが大きな狙いであり、脱燐
炉でのマンガン鉱石の添加にはそれほど重きを置いたも
のではなく、〔転炉滓十酸化鉄十蛍石〕を主成分とする
脱燐精錬剤に所望により添加する副次的なものでしかな
かった。However, the method proposed above focuses on adding manganese ore in the decarburization furnace, and thereby
The main aim is to increase the concentration of manganese ore in the dephosphorization furnace, and it is not so important to add manganese ore in the dephosphorization furnace. It was merely a secondary addition to the phosphorus refining agent if desired.
そして、この時の脱炭炉でのマンガン鉱石添加可能量は
“脱燐銑の温度と溶銑［Ｃ］濃度”及び“脱炭炉終点温
度と溶鋼［Ｃ］Ｎａ度”によって決定されるものであり
、従って、実際には添加主体となる脱炭炉でのマンガン
鉱石添加可能量も精々溶鉄トン当り１５〜２０ｋｇ程度
に過ぎず、脱炭炉終点［Ｍｎ］濃度も０．７〜０．９重
量％程度にしかならないものであった。The amount of manganese ore that can be added in the decarburization furnace at this time is determined by the "dephosphorization temperature and hot metal [C] concentration" and the "decarburization furnace end temperature and molten steel [C]Na degree." Therefore, in reality, the amount of manganese ore that can be added in the decarburization furnace, which is the main source of addition, is only about 15 to 20 kg per ton of molten iron, and the [Mn] concentration at the end of the decarburization furnace is 0.7 to 0.9. It was only about % by weight.
これに対して、高めのＭｎ含有量が要求される製品の［
Ｍｎ］濃度は１．５重量％程度とかなり高いものが多（
、そのため足りない分はやはり高価なフェロマンガン等
の添加で補う必要があり、本発明者等が先に提案した上
記方法は、このような観点からすれば今−歩物足りない
点のあることがその後の検討によって強く認識されるに
至ったのである。On the other hand, products that require a higher Mn content [
Mn] concentration is often quite high, around 1.5% by weight (
Therefore, it is necessary to compensate for the deficiency by adding expensive ferromanganese, etc. From this point of view, the above method proposed by the present inventors has some shortcomings. This has come to be strongly recognized through consideration of the following.
即ち、精錬後のフェロマンガン添加量を減らし＝８−
て高Ｍｎ鋼の製造コストをより低減するためには脱炭炉
終点［Ｍｎ］ 濃度を更に上げることが必要であるが、
前述した理由によりマンガン鉱石の添加・溶融還元可能
量に限界があることから、単に脱炭炉でのマンガン鉱石
添加量を増やす策は採用することができなかった。In other words, in order to further reduce the manufacturing cost of high Mn steel by reducing the amount of ferromanganese added after refining = 8-, it is necessary to further increase the [Mn] concentration at the end point of the decarburization furnace.
Due to the above-mentioned reasons, there is a limit to the amount of manganese ore that can be added and melted down, so it was not possible to simply increase the amount of manganese ore added in the decarburization furnace.
もっとも、溶銑予備処理による脱燐銑にマンガン鉱石を
投入しＭ ｎｔＲ度の高い溶鋼を転炉精錬（転炉を１基
だけ使用した通常の精錬）する際の終点［Ｍｎ］ ｉ１
！度をより一層向上させる手段として、コークスのよう
な炭材を添加するのが有効である事実も知られてはいる
。しかしながら、この方法を先に提案した方法での脱炭
精錬に適用したとしてもコークス使用による費用増を招
くばかりか、吹込み酸素費用も上昇し、吹錬時間の延長
（生産性の低下につながる）、コークスからの［Ｓ］上
昇。However, the end point [Mn] i1 when manganese ore is introduced into dephosphorized pig iron by hot metal pretreatment and molten steel with a high M ntR is refined in a converter (normal refining using only one converter).
! It is also known that it is effective to add a carbonaceous material such as coke as a means to further improve the carbon content. However, even if this method is applied to decarburization refining using the method proposed earlier, not only will the cost increase due to the use of coke, the cost of blown oxygen will also increase, and the blowing time will be extended (leading to a decrease in productivity). ), [S] rise from coke.
コークスからの脈石上界、脈石を中和するために添加す
る生石灰量の上昇、脈石及び生石灰量上昇の結果として
のスラグ量増大によるマンガン鉱石還元歩留の低下等が
生じ、成る程度のコスト低減−効果は認められるものの
、コークスを添加せずにマンガン鉱石を添加して溶融還
元する場合と同じ［Ｍｎｌ上昇量で比較すると、コーク
ス使用時の便益が小さくなるのを否定できなかった。The rise of gangue from coke, the increase in the amount of quicklime added to neutralize the gangue, and the decrease in the manganese ore reduction yield due to the increase in the amount of slag as a result of the increase in the amount of gangue and quicklime, etc. Although the cost reduction effect is recognized, it is the same as when manganese ore is added without adding coke and melted and reduced [When compared in terms of Mnl increase, it could not be denied that the benefit when using coke is smaller.
〈問題点を解決するための手段〉
そこで、本発明者等は、上下両吹き機能を有した２基の
転炉形式の炉のうちの一方を脱燐炉、他方を脱炭炉とし
て溶銑の精錬を行うと言う先に提案した製鋼方法の利点
を生かし、かつ前述した不利を伴うコークスの添加手段
によることなく脱炭炉での終点［Ｍｎ］ ９１１度を効
果的に上昇させることが可能な、“能率が良くて製造コ
ストの安い製鋼方法”を見出すべく研究を続けたところ
、更に次のような知見が得られた。即ち、
（ａ） 先に提案した方法では脱燐炉でのマンガン鉱
石添加を必須とはしなかったが、その脱燐炉でもマンガ
ン鉱石を必須の精錬剤として吹錬を行うと、このマンガ
ン鉱石も脱燐のための酸化剤として十分に作用する上、
脱燐炉で脱燐された溶銑の［Ｍｎ］ ｔｌｌｆｆ度を最
大限に高めることが簡単に可能となる。そして、この高
［Ｍｎ］ ｔＭ＝度の脱燐銑に更にマンガン鉱石を含む
造滓剤を投入して脱炭炉で精錬すると、極力少ない造滓
剤使用量の下で低燐でかつ［Ｍｎ］ ？１度の高い鋼を
コスト安く高能率で安定溶製することが可能となること
、
（ｂｌ 一般に溶銑脱燐用の精錬剤（フラックス）は
、生石灰、酸化鉄及び蛍石を主成分としていて、酸化鉄
は不可欠な成分とされており、本発明者等が先に提案し
た方法においても「スラグ中のＦｅＯを確保し脱燐を促
進するため、脱燐炉で添加する精錬剤（脱燐剤）中に酸
化鉄を含ませることが不可欠である」と認識されていた
（従って脱燐剤は〔転炉滓＋酸化鉄＋蛍石〕を主成分と
するものが良好とされていた）が、この場合、脱燐剤と
して酸化鉄を含まない〔転炉滓＋マンガン鉱石〕、或い
はこれに蛍石を配合したものを使用してもマンガン鉱石
が酸化鉄の代替剤として有効に作用し良好な脱燐が進行
すること、
（Ｃ１従って、転炉滓以外の必須成分であった酸化鉄に
代えてマンガン鉱石を含む精錬剤を脱燐炉での脱燐剤と
して使用すれば、酸化鉄添加に要する費用が削減された
上で十分に良好な脱燐を進行させることができく勿論、
マンガン鉱石は脱燐促進作用に加え、それ自身が［Ｃ］
等で還元されて脱燐銑の［Ｍｎ］をも効果的に上昇させ
る作用を発揮する）、この点からの製造コスト低減効果
も確保されること、
（ｄ） これらの結果、その後の脱炭炉精錬での終点
［Ｍｎ］がより高くなり（脱炭炉のみでマンガン鉱石添
加吹錬を行う場合の限界値よりも遥かに高い終点［Ｍｎ
］濃度が得られる）、マンガン合金鉄の顕著な節減が可
能となること。<Means for Solving the Problems> Therefore, the present inventors devised a system for converting hot metal by using one of two converter-type furnaces with both upper and lower blowing functions as a dephosphorization furnace and the other as a decarburization furnace. It is possible to effectively raise the end point [Mn] 911 degrees in the decarburization furnace by taking advantage of the previously proposed steelmaking method of refining, and without using the method of adding coke that has the disadvantages mentioned above. As they continued their research to find a steel manufacturing method that is efficient and has low manufacturing costs, they obtained the following findings. That is, (a) Although the previously proposed method did not require the addition of manganese ore in the dephosphorization furnace, if blowing is performed in the dephosphorization furnace with manganese ore as an essential refining agent, this manganese ore In addition to acting well as an oxidizing agent for dephosphorization,
It becomes possible to easily maximize the [Mn] tllff degree of hot metal dephosphorized in a dephosphorization furnace. Then, if a slag-forming agent containing manganese ore is further added to this high [Mn] tM = degree dephosphorization pig iron and refined in a decarburization furnace, it will be possible to obtain low-phosphorus and [Mn ] ? It is now possible to stably melt high-grade steel at a low cost and with high efficiency. (bl) Generally, the refining agent (flux) for hot metal dephosphorization has quicklime, iron oxide, and fluorite as its main components. Iron oxide is considered to be an essential component, and in the method previously proposed by the present inventors, ``in order to secure FeO in the slag and promote dephosphorization, a refining agent (dephosphorization agent) is added in the dephosphorization furnace. It was recognized that it is essential to include iron oxide in In this case, even if you use a dephosphorizing agent that does not contain iron oxide [converter slag + manganese ore] or a mixture of fluorite, the manganese ore will effectively act as a substitute for iron oxide and will work well. (C1) Therefore, if a refining agent containing manganese ore is used as a dephosphorizing agent in the dephosphorization furnace in place of iron oxide, which was an essential component other than the converter slag, iron oxide addition is possible. Of course, it is possible to proceed with sufficiently good dephosphorization while reducing the cost required for
In addition to promoting dephosphorization, manganese ore itself has [C]
(d) As a result of these, subsequent decarburization The end point [Mn] in furnace refining becomes higher (the end point [Mn] is much higher than the limit value when performing manganese ore addition blowing only in a decarburization furnace).
), and significant savings in manganese ferroalloys can be achieved.
この発明は、上記知見に基づいてなされたものであり、
「第１図に示される如く、上下両吹き機能を有した２基
の転炉形式の炉のうちの一方を脱燐炉ｌ、他方を脱炭炉
２として溶銑の精錬を行う製鋼方法において、前記脱燐
炉１内へ注入した溶銑３に前記脱炭炉２で発生した転炉
滓４及びマンガン鉱石（ここでは“鉄−マンガン鉱石”
を含めて“マンゴン鉱石”と総称する）を主成分とする
精錬剤を添加し、攪拌ガス吹込みノズル５による底吹き
ガス攪拌を行いつつ、ランス６より酸素ガスを上吹きし
て溶銑温度を１４００℃以下に保ちながら溶銑脱燐と溶
銑［Ｍｎ］の上昇を行う工程と、得られた脱燐溶銑に通
常造滓剤とマンガン鉱石とを投入して脱炭炉２で精錬し
、溶銑の脱炭と溶鉄の精錬終点［Ｍｎ］の上昇を図る工
程とを含ませることにより、極めて少ない量の造滓剤で
もって低い燐レベルで、しかも高い［’Ｍｎ］”含有量
の高品質鋼を作業性良く低コストで製造し得るようにし
た点」に特徴を有するものである。This invention was made based on the above-mentioned knowledge. ``As shown in FIG. In a steelmaking method in which hot metal is refined using decarburization furnace 2, hot metal 3 injected into dephosphorization furnace 1 is mixed with converter slag 4 generated in decarburization furnace 2 and manganese ore (here, "iron-manganese ore"). ”
A refining agent whose main component is mangon ore) is added, and while the bottom-blown gas is stirred by the stirring gas injection nozzle 5, oxygen gas is blown upward from the lance 6 to raise the temperature of the hot metal. A process of dephosphorizing the hot metal and raising the hot metal [Mn] while keeping the temperature below 1400°C, and adding a normal slag forming agent and manganese ore to the obtained dephosphorized hot metal and refining it in the decarburization furnace 2. By including decarburization and the process of increasing the smelting end point [Mn] of molten iron, high quality steel with a low phosphorus level and high ['Mn]' content can be produced with an extremely small amount of slag forming agent. It is characterized by being easy to work with and can be manufactured at low cost.
脱燐炉での処理温度を１４００℃以下に調整する理由□
は、溶銑処理温度がこれよりも高くなると脱炭ばかりが
進行してスラグ中の酸化剤量が低くなると共に、熱力学
的にも１４００℃以上では脱燐が悪化することにある。Reason for adjusting the treatment temperature in the dephosphorization furnace to below 1400℃□
The reason is that if the hot metal treatment temperature is higher than this, only decarburization will progress and the amount of oxidizing agent in the slag will decrease, and thermodynamically, dephosphorization will deteriorate at temperatures above 1400°C.
しかし、余りに低温になるとスラグへの粒鉄ロスが増加
するほか、その後の脱炭炉にて溶鋼中の［Ｍｎ］ ’１
ｌｌｓ度を高める上でも問題がある。However, if the temperature is too low, the loss of granular iron to the slag will increase, and [Mn] '1 in the molten steel in the subsequent decarburization furnace
There are also problems in increasing the degree of lls.
即ち、マンガン鉱石の溶融還元は
Ｍｎ０ｚ →−２［Ｃ］ →［Ｍｎｌ ＋ ２ＣＯなる
吸熱反応で進行する（マンガン鉱石の冷却能はスクラッ
プの約２．５倍もある）。従って、マンガン鉱石添加可
能量（溶融還元可能量）は溶銑の温度及び［Ｃ］？！度
が高いほど多くなる。そのため、脱燐処理は溶銑の温度
及び［Ｃ］ｓ度が高い状態で完了することが、脱炭炉に
おけるマンガン鉱石添加可能量を上昇させ、脱炭炉での
終点［Ｍｎｌ濃度を高める上で好ましい。ここで、温度
と［Ｃ］濃度が高い状態で脱燐処理を完了し易いように
、脱Ｐ炉に注湯する溶銑温度及び溶銑［Ｃ］濃度をでき
るだけ高くすることが先ず考えられるが、高炉の出銑温
度や高炉銑の［Ｃ］濃度を大きく変えることは技術的に
もコスト的にも問題がある。従って、脱燐処理時に溶銑
の温度と［Ｃ］濃度（即ち溶銑の顕熱と潜熱の合計）を
できるだけ下げないことが重要である。That is, the melting reduction of manganese ore proceeds through an endothermic reaction of Mn0z → -2 [C] → [Mnl + 2CO (the cooling capacity of manganese ore is about 2.5 times that of scrap). Therefore, the amount that can be added to manganese ore (the amount that can be reduced by melting) depends on the temperature of the hot metal and [C]? ! The higher the degree, the more it occurs. Therefore, completing the dephosphorization process while the hot metal temperature and [C]s degree are high increases the amount of manganese ore that can be added in the decarburization furnace and increases the Mnl concentration at the end point in the decarburization furnace. preferable. Here, in order to easily complete the dephosphorization process while the temperature and [C] concentration are high, the first idea is to raise the temperature and [C] concentration of the hot metal poured into the deP furnace as high as possible. Large changes in the tapping temperature and the [C] concentration of blast furnace pig iron are problematic both technically and cost-wise. Therefore, it is important to keep the temperature and [C] concentration of the hot metal (ie, the sum of the sensible heat and latent heat of the hot metal) as low as possible during the dephosphorization process.
従って、脱燐炉での処理温度は１４００°Ｃ以下の領域
の中で可能な限り高めに維持するのが良い。Therefore, the treatment temperature in the dephosphorization furnace is preferably maintained as high as possible within the range of 1400°C or less.
このような処理温度の維持は、上吹きランスからの酸素
ガス吹き込み或いは炉底羽口からの酸素ガス吹き込みの
併用によって行われる。つまり、上記脱燐炉での酸素ガ
ス吹き込みは、脱燐処理温度を保証するために行われる
のである。従って、ここでの上吹き酸素ランスは通常の
転炉ランスでも良いが、脱燐用に新作した小流量ランス
であっても良い。そして、使用酸素ガス量は処理前の溶
銑温度や珪素含有量、転炉滓の温度、脱燐炉の温もり具
合、目的とする処理溶銑温度等によって決定されるが、
概ね２ＯＮｍ３八以下で良く、通常は５〜１ＯＮｍ３／
ｌが効果的である。因に、このときの脱炭量は０．５％
程度である。This treatment temperature is maintained by blowing oxygen gas from the top blowing lance or by blowing oxygen gas from the bottom tuyere. In other words, the oxygen gas injection in the dephosphorization furnace is performed to ensure the dephosphorization treatment temperature. Therefore, the top blowing oxygen lance here may be a normal converter lance, but it may also be a new small flow rate lance for dephosphorization. The amount of oxygen gas used is determined by the temperature and silicon content of the hot metal before treatment, the temperature of the converter slag, the warmth of the dephosphorization furnace, the desired temperature of the hot metal to be treated, etc.
Generally, it should be less than 2ONm3, usually 5 to 1ONm3/
l is effective. Incidentally, the amount of decarburization at this time is 0.5%
That's about it.
前記「上下両吹き機能を有した転炉形式の炉」としては
現在使われている“上下吹き複合吹錬転炉”が最も好ま
しいが、特に脱燐炉については、精錬条件が脱炭炉より
もマイルドであるため炉口体を更に小さくしても良いの
で、脱燐専用に新設してもコスト的にそれほどの影響は
ない。As for the above-mentioned "converter type furnace with both top and bottom blowing functions", the currently used "top and bottom blowing combined blowing converter" is the most preferable. Since the dephosphorization process is also mild, the furnace mouth body can be made even smaller, so even if a new one is installed exclusively for dephosphorization, there will be no significant impact on the cost.
脱燐炉での精錬剤（脱燐剤）としては、脱炭炉で発生し
た転炉滓とマンガン鉱石を主成分とするものが使用され
るが、例えば、
転炉滓：４０〜８０重量％。As the refining agent (dephosphorization agent) in the dephosphorization furnace, one whose main components are converter slag generated in the decarburization furnace and manganese ore is used. For example, converter slag: 40 to 80% by weight .
マンガン鉱石：１０〜６０重量％。Manganese ore: 10-60% by weight.
蛍石二０〜３０重量％ の配合組成のものが推奨される。Fluorite 20-30% by weight A formulation with the following composition is recommended.
なお、マンガン鉱石は酸化鉄に比して滓化の点で幾分不
利であるため、蛍石は積極的に添加するのが良く、それ
も酸化鉄を配合する場合よりも多めとするのが望ましい
。In addition, since manganese ore is somewhat disadvantageous in terms of slag formation compared to iron oxide, it is better to actively add fluorite, and it is better to add more fluorite than when adding iron oxide. desirable.
この精錬剤は、勿論上記組成に限定されるわけではなく
、付加的に生石灰を配合しても良いし、ＣａＣｊ！ ２
＋ ＮａｚＯ’ ５ｔ（）ｚ、 ＮａｚＣＯ３等を加え
ても良い。また、マンガン鉱石の代わりに、前述したよ
うに鉄−マンガン鉱石を用いても良い。そして、転炉滓
以外のこれら脱燐剤原料は滓化性の面から小さい粒径程
好ましいが、′一般に使われている程度のものであれば
何ら差し支えない。This refining agent is, of course, not limited to the above composition, and quicklime may be added in addition, or CaCj! 2
+ NazO' 5t()z, NazCO3, etc. may be added. Further, instead of manganese ore, iron-manganese ore may be used as described above. The smaller the particle size of these dephosphorizing agent raw materials other than the converter slag is, the more preferable it is from the viewpoint of sludge formation, but there is no problem as long as it is of the level commonly used.
ところで、既に述べた如く、本発明者等が先に提案した
方法では、脱燐炉での脱燐剤は〔転炉滓＋酸化鉄＋蛍石
〕が重要な成分であり、このうち転炉滓は言うに及ばな
いが、酸化鉄も脱燐率を確保するために不可欠なものと
考えられていた。By the way, as already mentioned, in the method previously proposed by the present inventors, the important components of the dephosphorizing agent in the dephosphorizing furnace are [converter slag + iron oxide + fluorite], and among these, the dephosphorizing agent in the dephosphorizing furnace is In addition to slag, iron oxide was also considered essential for ensuring a high dephosphorization rate.
しかし、本発明者等は、この酸化剤として用いる酸化鉄
の代わりにマンガン鉱石を用いる方法を検討し、この場
合に酸化鉄を用いた場合と同様の脱燐率が得られると共
に、処理後の溶鉄の温度や［Ｃ］濃度も酸化鉄を用いた
場合と同レベルの状態に維持しつつ［Ｍｎｌ ｔａ度の
上昇を達成できることを突き止めて本発明を完成するに
至ったわけである。しかし、従来の生石灰系溶銑脱燐剤
（生石灰＋酸化鉄＋蛍石）を使用する場合に酸化鉄の代
わりに上述の如くマンガン鉱石を配合しても、フラック
スの滓化が非常に悪く、かつ脱燐に必要なスラグ中の酸
化力が確保できないので良好な脱燐は進行しない。とこ
ろが、転炉滓系の脱燐剤（転炉滓＋酸化鉄＋蛍石）のよ
うな場合、構成成分である“酸化鉄”を“マンガン鉱石
”に代えても良好な結果が得られる理由は、［転炉滓は
一度滓化したものであるためフラックスの滓化が良好で
あること」及び「転炉滓中に酸化鉄が１０〜２５重量％
程度含まれているため、これとマンガン鉱石の酸化力が
合わさって脱燐に必要な酸化力が確保できること」によ
ると考えられる。However, the present inventors investigated a method of using manganese ore instead of iron oxide used as the oxidizing agent, and in this case, the same dephosphorization rate as when using iron oxide could be obtained, and the The present invention was completed by discovering that it is possible to increase the [Mnl ta degree] while maintaining the temperature and [C] concentration of molten iron at the same level as when iron oxide is used. However, when using the conventional quicklime-based hot metal dephosphorizing agent (quicklime + iron oxide + fluorite), even if manganese ore is mixed as described above instead of iron oxide, the flux becomes very poor in slag formation, and Since the oxidizing power in the slag necessary for dephosphorization cannot be secured, good dephosphorization does not proceed. However, in the case of a dephosphorizing agent based on converter slag (converter slag + iron oxide + fluorite), why can good results be obtained even if the component "iron oxide" is replaced with "manganese ore"? [The converter slag has been turned into slag once, so the flux is well converted into slag.] and [The converter slag contains 10 to 25% by weight of iron oxide.]
This is thought to be due to the fact that this and the oxidizing power of the manganese ore combine to secure the oxidizing power necessary for dephosphorization.
マンガン鉱石の溶融還元（自身は酸化剤として作用する
）量は、添加量によっても異なるが、例えば投入量１０
ｋｇ／ｌで［Ｍｎ］増加量は０．３〜０．４％程度であ
る。The amount of manganese ore reduced by melting (itself acts as an oxidizing agent) varies depending on the amount added, but for example, the amount of manganese ore added is 10
The increase in [Mn] in kg/l is about 0.3 to 0.4%.
この場合、マンガン鉱石の添加歩留を高くするためには
スラグ塩基度を２．５以上にした方が有利である。その
理由を第２図を用いて説明する。In this case, in order to increase the addition yield of manganese ore, it is advantageous to set the slag basicity to 2.5 or more. The reason for this will be explained using FIG. 2.
第２図は“脱燐炉のスラグ中（Ｍｎ） ［実際はＭｎＯ
の形態であるＭｎ分を重量％で表わしたもの］と溶銑［
Ｍｎ］との比（Ｍｎ分配比）″ と“スラグ塩基度”と
の関係を示したものであるが、この第２図からも明らか
なように、塩基度が高くなるほど（Ｍｎ）／［Ｍｎ］は
小さくなることが分かる。つまり、スラグ塩基度が高い
ほど酸化マンガンは還元され易くなり、スラグ塩基度が
２．５以上の領域ではこの傾向が最も強くなって一定化
することを確認できる（なお、フラグ塩基度が高くなる
ほど脱硫も進行し易くなり、Ｃａｂ／Ｓｉｎｇが３の場
合には脱硫率が６０％程度になることも確認済みである
）。Figure 2 shows “(Mn) in the slag of the dephosphorization furnace [Actually, MnO
Mn content in the form of [% by weight]] and hot metal [
Figure 2 shows the relationship between the ratio of Mn] (Mn distribution ratio) and the slag basicity.As is clear from Figure 2, the higher the basicity, the greater the ] becomes smaller. In other words, the higher the slag basicity, the more easily manganese oxide is reduced, and it can be confirmed that this tendency becomes strongest and becomes constant in the region where the slag basicity is 2.5 or more ( Note that desulfurization progresses more easily as the flag basicity increases, and it has been confirmed that when Cab/Sing is 3, the desulfurization rate is about 60%).
スラグの塩基度を高くするためには、脱炭炉の転炉滓量
を多くする方法があるが、転炉滓と共に生石灰を補助的
に添加しても良い。In order to increase the basicity of slag, there is a method of increasing the amount of converter slag in the decarburization furnace, but quicklime may be added as an auxiliary together with the converter slag.
脱燐炉で使用される精錬剤（脱燐剤）の量は溶製する鋼
の［Ｐ］ レベルにより決定されるが、通常は３０〜６
０ｋｇ／を程度で良い。The amount of refining agent (dephosphorizing agent) used in the dephosphorizing furnace is determined by the [P] level of the steel to be melted, but it is usually 30 to 6
0kg/or so is fine.
さて、脱燐炉で使用される精錬剤の主成分たる転炉滓と
しては、脱炭炉で発生した溶融状態のものが熱経済的に
も脱燐フラフクスの滓化性の面からも好ましいが（この
ように熔融状態のものを用いる場合には耐火物を内張す
した鍋を介して脱燐炉に注滓される）、取り扱いの容易
さ等を考慮して脱炭炉で得られたものを一旦冷却凝固さ
せ、粒状又は塊状に破砕してから用いても良い（なお、
この時も熱的な面からスラグの温度は高い程良い）。Now, as the converter slag, which is the main component of the refining agent used in the dephosphorization furnace, the molten slag generated in the decarburization furnace is preferable from the viewpoint of thermoeconomics and the ability to form slag of the dephosphorization fluff. (When using a molten substance like this, it is poured into a dephosphorization furnace through a pot lined with a refractory). It may be used after cooling and solidifying the material and crushing it into granules or chunks (in addition,
Also at this time, from a thermal standpoint, the higher the slag temperature, the better.)
ただ、この場合、脱燐炉での滓化性向上のために粒径は
小さい程良好であるが、転炉滓は本来滓化性に富んでい
ることもあって粒径が１００鰭を下回る程度でも格別な
不都合を来たすことがないし、これより大きくても使用
可能である。However, in this case, the smaller the particle size is, the better it is in order to improve the ability to form slag in the dephosphorization furnace, but since converter slag is inherently highly slag-formable, the particle size is less than 100 fins. Even if the size is larger, it will not cause any particular inconvenience, and it can be used even if it is larger than this.
そして、使用される転炉滓は、タイミングとしては前回
チャージのものが良いが、それ以前に脱炭炉から出たも
のや他の工場の脱炭炉で発生したものでも良いことは言
うまでもない。The timing of the converter slag to be used is preferably that of the previous charge, but it goes without saying that it may also be that which came out of the decarburizing furnace before that or that which was generated in the decarburizing furnace of another factory.
炉底から吹き込む攪拌ガスとしてはＡｒ、ＣＯ２１ＣＯ
，Ｎ、、Ｏ□、空気等の何れであっても良い。The stirring gas blown from the bottom of the furnace is Ar, CO21CO.
, N, , O□, air, etc. may be used.
そして、脱燐炉の炉底ガス攪拌の程度は通常の上下両吹
き複合吹錬におけると同程度（０，０３〜０．２Ｎｍ’
／ｌ ）で良いが、脱燐速度の向上を狙ってこれよりも
更に多くして良いことは勿論である。The degree of agitation of the bottom gas in the dephosphorization furnace is the same as in normal double blowing combined blowing (0.03 to 0.2 Nm'
/l), but it is of course possible to increase the amount even more with the aim of improving the dephosphorization rate.
以上のような条件で脱燐処理を行うと、通常、２０分以
内で所望の高［Ｍｎ］濃度の脱燐銑を得ることができる
。When dephosphorization treatment is carried out under the above conditions, dephosphorized pig iron with a desired high [Mn] concentration can usually be obtained within 20 minutes.
そして、このようにして脱燐炉で［Ｍｎ］を上昇させた
脱燐銑を脱Ｃ炉で吹錬する場合、添加マンガン鉱石量を
増加させるためにコークス等の炭材を熱源として添加し
ても良いことは言うまでもない。When the dephosphorized pig iron with increased [Mn] in the dephosphorizing furnace is blown in the dephosphorizing furnace, carbonaceous material such as coke is added as a heat source to increase the amount of added manganese ore. Needless to say, it's a good thing.
゛脱炭炉での吹錬は、基本的には通常の“炉外で脱燐さ
れた溶銑”を吹錬する場合と同じであるが、終点での溶
鋼の［Ｍｎ］ ｔＭ度を向上させるため、生石灰やドロ
マイトを中心とする造滓剤の他にマンガン鉱石が添加さ
れる。゛Blowing in a decarburizing furnace is basically the same as blowing ordinary hot metal that has been dephosphorized outside the furnace, but it improves the [Mn] tM degree of the molten steel at the end point. Therefore, manganese ore is added in addition to slag-forming agents, mainly quicklime and dolomite.
ところで、この発明に係る製鋼法を実施する場合には、
出来れば適用される溶銑の事前脱硫処理を行うのが良い
。その第一の理由として該製鋼法では脱硫の進行が極め
て鈍いことが挙げられるが、他方では、事前脱硫してい
ない溶銑を用いた場合には転炉スラグ中のＳ含有量が上
昇し、次のチャージにおける溶鋼Ｓ含有量を高めること
も懸念されるからである。なお、前記事前脱硫は通常行
われている溶銑脱硫方法の何れによっても良い。By the way, when implementing the steel manufacturing method according to this invention,
If possible, it is better to perform a preliminary desulfurization treatment on the applied hot metal. The first reason is that the progress of desulfurization is extremely slow in this steelmaking method, but on the other hand, when hot metal that has not been desulfurized in advance is used, the S content in the converter slag increases, and the This is because there is also concern about increasing the molten steel S content in the charge. Note that the preliminary desulfurization may be performed by any of the commonly used hot metal desulfurization methods.
更に、この方法に適用される原料溶銑のＳｉ含有量も低
い程好ましい。なぜなら、溶銑中のＳｉ含有量が多くな
るほど前記脱燐炉でのスラグ塩基度が低下して脱燐能が
落ち、全体での生石灰等の使用量が増加するためである
。それ故、溶銑のＳｉ含有量は出来れば０．３％以下、
好ましくは０．２％以下に調整しておくのが良策である
。なお、脱炭炉の条件から処理後の溶銑温度を少しでも
高くしたいような場合、溶銑のＳｉ含有量は０．２％程
度の方が有利なこともあり、工場のローカル条件によっ
て決定すべきである。Furthermore, the lower the Si content of the raw material hot metal used in this method, the better. This is because as the Si content in the hot metal increases, the basicity of the slag in the dephosphorization furnace decreases, the dephosphorization ability decreases, and the total amount of quicklime etc. used increases. Therefore, the Si content of hot metal should be 0.3% or less if possible.
Preferably, it is a good idea to adjust it to 0.2% or less. In addition, if it is desired to raise the hot metal temperature after treatment due to the conditions of the decarburization furnace, it may be advantageous to set the Si content of the hot metal to about 0.2%, so it should be determined according to the local conditions of the factory. It is.
次に、この発明を比較例と対比した実施例により更に具
体的に説明する。Next, the present invention will be explained in more detail with reference to examples in comparison with comparative examples.
〈実施例〉
比較例
トーピード内で脱硫・脱珪処理した第１表の上段に示さ
れる如き成分の溶銑２５０トンを脱燐炉として使用する
上下両吹き複合吹錬転炉に注銑し、これに同様形式の脱
炭炉で発生した転炉滓を冷却・凝固して３０ｗ以下の粒
径に破砕したもの２５ｋｇ／ｌと、同様の粒径を持つ鉄
鉱石１２ｋｇ／を並びに蛍石８ｋｇ八とを混合状態で添
加して１３分間の脱燐処理を行った。<Example> Comparative Example 250 tons of hot metal having the composition shown in the upper row of Table 1, which had been desulfurized and desiliconized in a torpedo, was poured into an upper and lower double blowing combined blowing converter used as a dephosphorization furnace. 25 kg/l of converter slag generated in a similar type of decarburizing furnace by cooling and solidifying it and crushing it to a particle size of 30 W or less, 12 kg/l of iron ore with a similar particle size, and 8 kg/l of fluorite. were added in a mixed state to perform dephosphorization treatment for 13 minutes.
なお、使用した脱燐炉並びに脱炭炉は、何れも炉底より
ガス吹込み攪拌が可能な２５’Ｏトン上下両吹き複合吹
錬転炉であり、第２表に示したような操業条件が採用さ
れた。The dephosphorization furnace and decarburization furnace used were both 25'O ton top and bottom double blowing combined blowing converters capable of gas injection and stirring from the bottom of the furnace, and the operating conditions were as shown in Table 2. was adopted.
このようにして得られた脱燐銑（成分組成は第１表の中
段に示す）を、−旦鍋中に出銑してから脱炭炉に注銑し
、更に生石灰８ｋｇ／ｌ、 ドロマイト５ｋｇ／ｌ、
蛍石１ ｋｇ／を及びマンガン鉱石２０ｋｇ／ｌを添加
してから主吹錬を実施した。The dephosphorized pig iron thus obtained (composition is shown in the middle row of Table 1) was tapped into a hotpot and then poured into a decarburization furnace, and additionally 8 kg/l of quicklime and 5 kg of dolomite were poured into the decarburizing furnace. /l,
Main blowing was carried out after adding 1 kg/l of fluorite and 20 kg/l of manganese ore.
このとき発生した転炉滓は２５ｋｇ／ｌであり、これを
鉄鉱石及び蛍石と共に次のチャージの脱燐剤原料として
脱燐炉に添加し脱燐を行うと言う一連の操作を繰り返し
た。The converter slag generated at this time was 25 kg/l, and a series of operations were repeated in which it was added to the dephosphorization furnace as a dephosphorizing agent raw material for the next charge together with iron ore and fluorite, and dephosphorization was performed.
この結果、全製鋼工程での使用生石灰及びドロマイト量
が合計で１３ｋｇ八と言う少ない値で、第１表の下段に
示すような網中［Ｐ］が０．０１１重量％、 ［Ｍｎ
］が０．８２重量％と言う溶鋼が得られた。As a result, the total amount of quicklime and dolomite used in the entire steelmaking process was as small as 13 kg, and [P] in the mesh was 0.011% by weight and [Mn] as shown in the lower part of Table 1.
] 0.82% by weight was obtained.
なお、第１表で脱燐後の［Ｍｎ］が上昇しているのは、
脱炭炉で発生した転炉滓中の（ＭｎＯ）が１８重量％と
高くなっていたことによるものである。In addition, the reason why [Mn] increases after dephosphorization in Table 1 is because
This is because (MnO) in the converter slag generated in the decarburization furnace was as high as 18% by weight.
実施例 １
脱燐炉内に注銑した第３表の上段に示される如き成分の
脱硫・脱珪溶銑２５０トンに、脱炭炉で発生した転炉滓
２５ｋｇ／ｌと蛍石８ｋｇ／ｌのほか、鉄鉱石に代えて
粒径３０ｍｍ以下のマンガン鉱石１２ｋｇへを添加した
以外は上記比較例の場合と同様条件で脱燐処理を行った
。Example 1 250 tons of desulfurized and desiliconized hot metal having the composition as shown in the upper part of Table 3 was poured into a dephosphorization furnace, and 25 kg/l of converter slag generated in the decarburizing furnace and 8 kg/l of fluorite were added. In addition, dephosphorization was performed under the same conditions as in the comparative example, except that 12 kg of manganese ore with a particle size of 30 mm or less was added instead of iron ore.
次いで、このようにして得られた脱燐銑（成分組成は第
３表の中段に示す）を前記比較例と同様条件で脱炭炉に
おいて精錬した。Next, the dephosphorized pig iron thus obtained (the composition is shown in the middle row of Table 3) was refined in a decarburization furnace under the same conditions as in the comparative example.
その結果、第３表の下段に示すような溶鋼が得られ、脱
炭炉での終点［Ｍｎ］が１．０５重量％まで上昇したこ
とが明らかとなった。勿論、全製鋼工程での使用生石灰
及びドロマイト量が少なくて済んだことは比較例の場合
と同様であった。As a result, molten steel as shown in the lower row of Table 3 was obtained, and it was revealed that the end point [Mn] in the decarburization furnace increased to 1.05% by weight. Of course, as in the comparative example, the amount of quicklime and dolomite used in the entire steelmaking process was small.
このように、脱燐炉での精錬剤として鉄鉱石に代えてマ
ンガン鉱石を用いる本発明方法によると、前記比較例の
場合に比して０．２３％より高い［Ｍｎ］上昇を確保で
きることが確認された。As described above, according to the method of the present invention in which manganese ore is used instead of iron ore as a refining agent in the dephosphorization furnace, it is possible to secure an increase in [Mn] higher than 0.23% compared to the case of the comparative example. confirmed.
実施例 ２
第４表の上段に示される如き成分の脱硫・脱珪溶銑２５
０トンを対象に、脱燐剤（脱燐炉での精−２５＝
練剤）として
脱炭炉、で発生した転炉滓： ２５ｋｇ／ｌ。Example 2 Desulfurization and desiliconization hot metal 25 with the components shown in the upper row of Table 4
Converter slag generated in the decarburizing furnace as a dephosphorizing agent (refining agent in the dephosphorizing furnace): 25 kg/l.
マンガン鉱石： １２ｋｇ／ｌ。Manganese ore: 12kg/l.
生石灰： ７ｋｇ／ｌ。Quicklime: 7kg/l.
蛍石： １０ｋｇ／ｌ
の配合物を用いたほかは実施例１と同様の転炉吹錬を実
施した。Fluorite: Converter blowing was carried out in the same manner as in Example 1, except that a 10 kg/l mixture was used.
この時の脱燐溶銑組成を第４表の中段に、そして脱炭炉
における終点溶鋼組成を第４表の下段に示す。The dephosphorized hot metal composition at this time is shown in the middle row of Table 4, and the final point molten steel composition in the decarburization furnace is shown in the lower row of Table 4.
第４表からも明らかなように、この精錬によって脱炭炉
における終点［Ｍｎ］を１．１３重量％まで上昇するこ
とができた。As is clear from Table 4, this refining made it possible to raise the end point [Mn] in the decarburization furnace to 1.13% by weight.
これは、前記比較例の場合と比べて０．３１％高い［Ｍ
ｎ］上昇が確保されたことを意味するものである。This is 0.31% higher than that of the comparative example [M
n] means that the increase has been secured.
〈効果の総括〉
以上に説明した如く、一般に脱炭炉においてマンガン鉱
石を使用した場合、これらの約半分はＭｎにまで還元さ
れずに酸化物としてスラグ中に残る＝２６−
が、この発明によれば、該スラグを溶銑脱燐フラックス
として再使用するので上記残留鉱石の有効利用がなされ
、溶銑脱燐段階における“［Ｍｎ］ロスの軽減”或いは
” ［Ｍｎ］上昇”に役立つ。また、脱炭炉にマンガン
鉱石を添加して還元させるので、脱炭炉における終点［
Ｍｎ］を従来法に比べ０．２〜０．３重量％程度も安定
かつ安価に上昇させることができる゛。従って、フェロ
マンガン添加量を粗鋼１トン当り３〜４ｋｇ節減するこ
とが可能となる上、製鋼工程の全体を通じて必要な造滓
剤量の著しい低減も達成できるなど、産業上極めて有用
な効果がもたらされるのである。<Summary of Effects> As explained above, when manganese ore is generally used in a decarburization furnace, about half of it is not reduced to Mn and remains in the slag as oxide =26-, but this invention According to this method, since the slag is reused as hot metal dephosphorization flux, the residual ore is effectively utilized, which is useful for "reducing [Mn] loss" or "increasing [Mn]" in the hot metal dephosphorization step. In addition, since manganese ore is added to the decarburization furnace and reduced, the end point in the decarburization furnace [
Mn] can be stably and inexpensively increased by about 0.2 to 0.3% by weight compared to conventional methods. Therefore, it is possible to reduce the amount of ferromanganese added by 3 to 4 kg per ton of crude steel, and it is also possible to achieve a significant reduction in the amount of slag forming agent required throughout the entire steelmaking process, resulting in extremely useful effects industrially. It is possible.
第１図は、本発明プロセスの概念図である。
第２図は、脱燐炉でのＭｎ分配比とスラグ塩基度との関
係を示したグラフである。
第３図は、先に提案した製鋼法に係るプロセスの概念図
である。
図面において、
１・・・脱燐炉１ ２・・・脱炭炉。
３・・・溶銑、 ４・・・転炉滓。
４′・・・転炉滓を主成分とする脱燐スラグ。
５・・・攪拌ガス吹き込みノズル。
６・・・ランス。FIG. 1 is a conceptual diagram of the process of the present invention. FIG. 2 is a graph showing the relationship between the Mn distribution ratio and the slag basicity in the dephosphorization furnace. FIG. 3 is a conceptual diagram of the process related to the steel manufacturing method proposed earlier. In the drawings: 1...Dephosphorization furnace 1 2...Decarburization furnace. 3... Hot metal, 4... Converter slag. 4'...Dephosphorization slag whose main component is converter slag. 5... Stirring gas blowing nozzle. 6... Lance.
Claims (2)
ちの一方を脱燐炉、他方を脱炭炉として溶銑の精錬を行
う製鋼方法において、前記脱燐炉内へ注入した溶銑に前
記脱炭炉で発生した転炉滓及びマンガン鉱石を主成分と
する精錬剤を添加し、底吹きガス攪拌を行いつつ酸素ガ
スを上吹きして溶銑温度を１４００℃以下に保ちながら
溶銑脱燐と溶銑［Ｍｎ］の上昇を行う工程と、得られた
脱燐溶銑に通常造滓剤とマンガン鉱石とを投入して脱炭
炉で精錬し、溶銑の脱炭と溶鉄の精錬終点［Ｍｎ］の上
昇を図る工程とを含むことを特徴とする製鋼方法。(1) In a steelmaking method in which hot metal is refined by using one of two converter type furnaces with upper and lower blowing functions as a dephosphorization furnace and the other as a decarburization furnace, the hot metal is injected into the dephosphorization furnace. A refining agent mainly composed of converter slag and manganese ore generated in the decarburization furnace is added to the hot metal, and the hot metal is heated while maintaining the hot metal temperature at 1400°C or less by blowing oxygen gas upward while stirring the bottom blowing gas. A process of dephosphorization and raising of hot metal [Mn], a normal slag-forming agent and manganese ore are added to the obtained dephosphorized hot metal and smelting in a decarburization furnace, and the end point of decarburization of hot metal and refining of molten iron [ 1. A steelmaking method comprising: a step of increasing Mn].
まで予備脱珪処理されたものである、特許請求の範囲第
１項に記載の製鋼方法。(2) The steelmaking method according to claim 1, wherein the hot metal to be treated has been subjected to preliminary desiliconization treatment to reduce the Si content to 0.30% by weight or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30126287A JPH01142009A (en) | 1987-11-28 | 1987-11-28 | Steel making method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30126287A JPH01142009A (en) | 1987-11-28 | 1987-11-28 | Steel making method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01142009A true JPH01142009A (en) | 1989-06-02 |
| JPH0437134B2 JPH0437134B2 (en) | 1992-06-18 |
Family
ID=17894699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30126287A Granted JPH01142009A (en) | 1987-11-28 | 1987-11-28 | Steel making method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01142009A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03153811A (en) * | 1989-11-08 | 1991-07-01 | Sumitomo Metal Ind Ltd | Steelmaking method accompanied with smelting reduction of manganese ore |
| JPH05140627A (en) * | 1991-11-16 | 1993-06-08 | Nippon Steel Corp | Steelmaking method in converter |
-
1987
- 1987-11-28 JP JP30126287A patent/JPH01142009A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03153811A (en) * | 1989-11-08 | 1991-07-01 | Sumitomo Metal Ind Ltd | Steelmaking method accompanied with smelting reduction of manganese ore |
| JPH05140627A (en) * | 1991-11-16 | 1993-06-08 | Nippon Steel Corp | Steelmaking method in converter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0437134B2 (en) | 1992-06-18 |
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