JP3852128B2 - Method for producing molten metal using carbonized material packed bed smelting reduction furnace - Google Patents

Description

の反応が起こり、脱燐が促進される。
【００１０】
そこで、上段羽口から酸化鉄を含有する粉粒状の鉱石類（スラジ、ダストを含む）からなる酸化鉄原料を装入するに際し、酸化鉄原料中のSiO₂濃度を大きくすることで、上段羽口前のSiO₂濃度を大きくし、前記化学反応式（２）、（３）の反応をさせることにより、脱燐反応はより促進する。そして、還元された燐は、炉内ガスと共に炉内を上昇するが、温度の低下に伴い一部はダスト等に付着し、また一部はPN、PS、PO、PO₂ 等の化合物になって炉頂から排ガスと共に抜け出し、レースウェイ下部のコークス中の燐濃度は低下する。
（Ｂ） 酸化鉄原料（鉱石類）中に含まれている燐は、前記羽口先に形成されるレースウェイ近傍において下記の化学反応式（４）により還元されるため、レースウェイ下部でコークス中の燐濃度は低下することになる。
【００１１】
２Ｆｅ₃ （ＰＯ₄ ）₂ ＋１６ＣＯ→３Ｆｅ₂ Ｐ＋Ｐ＋１６ＣＯ₂ ・・・(4)
つまり、羽口から吹き込んだ酸化鉄原料は、レースウェイ部分で溶融し、前記化学反応式（４）の反応により一部の燐は炉内を上昇し、溶融物はコークス間を滴下しながら還元されて炉下部に移動し、銑鉄となる。その際、前記化学反応式（１）の反応によってコークス中の燐濃度は低下しているので、滴下する間に溶融物がコークス中の燐を吸収する量が少なく、溶銑中の燐濃度は低くなる。炉頂から装入された全ての炭材が炭材充填層における1700℃以上の領域を通過する場合、燐と酸化鉄が共存するレースウェイ部分では温度が十分高温なので、気体の燐は速やかに炉内を上昇し、溶融物は粘度が小さくすぐに滴下するので、溶銑中への燐のトラップはほとんど起きない。
【００１２】
なお、吹き込む酸化鉄原料の粒径が細かければ細かいほど、個々の粒子の中心までの伝熱が速いため、短時間で昇温し易く前記化学反応式（４）の反応は、よりスムーズに行われる。また、高温であるほど粘度が小さくなるので、燐と溶銑との共存時間が短くなるため、溶銑中の燐濃度が低下する。さらに、レースウェイに吹き込まれた酸化鉄は、溶融し、吸熱反応で還元されるため、コークス温度を低下させる方向に作用する。そこで、吹き込む酸化鉄として不純物の少ないものを用い、不純物昇温のための無駄な熱量を小さくしたり、吸熱量の小さい酸化鉄を用いたりすることにより、溶銑中の燐濃度の低下を促進することも可能である。前記（Ｂ）で説明した酸化鉄原料（鉱石類）から脱燐した燐も、温度の低下にともない一部はダスト等に付着し、また、一部はP 、N 、PS、PO、PO₂ 等の化合物になり炉頂から抜け出し、除去される。
【００１３】
しかしながら、炭材充填層型の溶融還元炉における製錬領域は、レースウェイ空間とその下部の溶融物が滴下する部分が主体で、しかもこの製錬領域での反応の大半は吸熱反応である。この熱を補償するため、下段羽口で炭材を燃焼させ、送風熱量で補償する必要があった。また、この炉で生産量を増やそうとして大量の酸化鉄原料粉を羽口から吹き込んだ場合、レースウェイ部で大きな吸熱反応が起こり、レースウェイ周辺の温度が1700℃以下になってしまい、溶銑中の燐濃度が上昇する。そのため、多量の炭材を燃焼させて熱補償する必要があった。
【００１４】
さらに、下段羽口で多量の炭材コークスを燃焼させると、上下羽口間の炭材の降下速度が速くなり、融体の上下羽口間の滞留時間が短くなるので、未還元のまま融体が滴下する。上下羽口間の滞留時間を確保して還元を進めるためには、上下羽口間の距離を十分長くする必要があり、設備的に炉高を高くする必要があった。つまり、この炭材充填層型の溶融還元炉でコークス中の燐を十分気化させるためには、設備費が嵩む炉高の高い炉とし、かつ高価な炭材を多量に使用しなければならないという問題点があった。
【００１５】
そこで本出願人は、炭材充填層型溶融還元炉の特性を生かして、燐含有量が0.05％以下の低燐銑を安価に大量生産可能な方法として、特開平5-9527号公報及び特開平5-247549号公報等に開示されている方法を提案した。それは、炭材充填層型の溶融還元炉が高炉と異なり、炉内に所謂軟化融着体が形成されず燐の炉内循環が起きないので、低燐銑の製造に好ましいからである。つまり、前記公報で明らかにしたように、炉内温度を高温に調整することで気化脱燐が可能になるのである。このように、本出願人が提案した炭材充填層型の溶融還元炉は、将来のエネルギー源の枯渇問題を解決するばかりでなく、燐含有量の低い銑鉄の製造にも好適である。
【００１６】
しかしながら、これまでに提案された炭材充填層型の溶融還元炉を用いる製錬方法は、低燐銑製造の観点からは未だに問題点を残している。すなわち、特開平5-9527号公報に開示された従来技術においては、上段羽口吹き込む酸化鉄原料として、FeO を20％以上含むものを必要とし、また特開平5-247549号公報に開示された従来技術においてはやはり、羽口から吹き込む酸化鉄原料として、気化した燐が凝集した金属酸化物を必要とする。このような酸化鉄原料は、金属酸化物鉱石として一般的なものでなく、したがって、これらの溶融還元処理プロセスは、酸化鉄原料の選択範囲が狭く、限られた場合にしか使用できないという弱点があった。
【００１７】
前記のような特定の酸化鉄原料を使用できない場合、従来の溶融還元炉に設けた羽口から吹き込んだ酸化鉄原料中の燐は、高温のレースウェイ内で気化されるが、酸化鉄原料粉が十分に分散しない状態で溶融するため、レースウェイ内部で溶融還元が進行してしまう。このため、生成したメタルに燐ガスが吸収され、結果として所望の低燐銑を製造するのが困難である。このように、これまで提案された炭材充填層型の溶融還元炉を用いる製錬方法は、低燐銑製造の観点からは未だ問題点を残している。
【００１８】
【発明が解決しようとする課題】
油を含んだ金属屑、金属スラジまたは金属ダスト等は、金属原料として有用なＮｉ、Ｍｏ等を含有しているうえに、安価に入手できるものであり、従来からその有効利用が望まれていた。しかし、電気炉や転炉等で溶解使用すると油分が気化して排ガス系を詰まらせるという問題がある。また、高炉の羽口に気体輸送して吹き込もうとすると粘性の高い油分のため、搬送管や吹き込み管内に付着し、詰まりを生じて長時間の吹き込みが困難である。一方、スラリー状にして吹き込もうとすると、炉内圧力が高いために、吹き込み管先で原料粉の付着が生じ、これが徐々に成長してスラッギングを生じ、やはり安定した吹き込みができないという問題点があり、実用化されなかった。したがって、現在では、含油金属屑等は、予め脱脂洗浄処理をして使用しているため、その処理コストによって、安価な金属原料という利点が損なわれていた。
【００１９】
炭材充填層型の溶融還元炉は、金属酸化物原料、たとえば、酸化鉄原料として鉄鉱石類の他に転炉吹錬の際に発生するスラジやダスト等の製鉄所から生じる各種スラジあるいはダストを利用できるメリットがあるうえに、油を含む金属屑等の含油金属原料を利用することができる。さらに、高価な電力あるいは強粘結炭を使用することなく、比較的安価な弱粘結炭あるいは非粘結炭を使用するので、益々エネルギーコストの上昇が危惧される今後の溶銑の製造炉として期待できる。本発明は、かかる事情に鑑みてなされたものであり、低燐コークス等の高価な炭材を用いることなく、燐含有量が0.05重量％以下の低燐溶銑等の燐含有量の低い溶融金属を原料鉱石類の品位によることなく安価に大量生産することができる炭材充填層型溶融還元炉による溶融金属の製造方法を提供することを目的とするものである。
【００２０】
【課題を解決するための手段】
本発明者らは、前記目的を達成するため、鋭意研究を行い、本来脱燐に有利な炭材充填層型の溶融還元炉が有する特性を活用し、油分を含有する繊維状や粉状の金属屑または金属含有スラジや金属含有ダストを用いることに着目し、種々実験を重ねた結果なされたものである。すなわち、炭素系固体還元材の充填層を形成した溶融還元炉に直接吹き込む繊維状や粉状の金属屑または金属含有スラジや金属含有ダストに、必要に応じて廃油等の液体流動物を加えた各種スラリー状含油金属原料を使用し、これらを単独に、あるいは適宜に組み合わせることによって炉内での気化脱燐を促進させることに成功し、本発明を完成させるに至った。
【００２１】
すなわち、請求項１記載の本発明は、溶融還元炉内に炭素系固体還元剤の充填層が形成され、炉下部に少なくとも上下２段に配設された複数の羽口より酸素含有熱風を吹き込むと共に、前記複数の羽口のうち最上段に位置する羽口または最上段羽口を包含する選択した羽口に配置したメインランスを用いて、粉粒状の金属酸化物原料を前記充填層内に吹き込み、前記金属酸化物原料を溶融還元して溶融金属を製造する炭材充填層型溶融還元炉による溶融金属の製造方法において、前記複数の羽口のうち最上段羽口の位置および／または最上段羽口より下部の位置に配置したサブランスを用いて、前記充填層内に油分と金属分を含有するスラリー状含油金属原料を吹き込むことを特徴とする炭材充填層型溶融還元炉による溶融金属の製造方法である。
【００２２】
請求項２記載の本発明は、油分と金属分を含有するスラリー状含油金属原料が、油分を含有する繊維状金属屑、粉状金属屑、金属含有スラジまたは金属含有ダストから選択した１種または２種以上に、液体流動物を加えたスラリー状金属原料であることを特徴とする請求項１記載の炭材充填層型溶融還元炉による溶融金属の製造方法である。
【００２３】
【発明の実施の形態】
従来は、炭素系固体還元材（炭材）の充填層が形成され、炉腹下部に高温の酸素含有熱風（空気又は酸素富化空気）を吹き込む少なくとも上下２段に設けた複数の羽口を有する炭材充填層型の溶融還元炉を用いて、羽口より酸素含有熱風と共に、酸化鉄を含有する粉粒状の鉱石類を酸化鉄原料として充填層内に吹き込み、酸化鉄原料中の酸化鉄を溶融還元して溶銑を製造していた。しかし、前述のように従来の操業では、羽口から吹き込んだ酸化鉄原料中の燐が高温のレースウェイ内で気化されるが、レースウェイ内部で溶融還元により生成したメタルが存在するため、気化した燐の大部分がメタルに溶解し、溶銑の脱燐を不十分なものにしていた。
【００２４】
メタル中に移行する燐源としては、他に還元材である炭材に含有される燐分もあり、炭材中の燐はメタルとの直接接触により、あるいは一旦炭材の灰分と共にスラグに溶解したうえで、スラグ／メタル間の反応によりメタル中に移行する。このような燐の移行現象を解明したうえで、本発明者らは、このメタル中の燐分を低減するには、下記の方策が有効であることに思い至った。
【００２５】
（１）レースウェイ内部で気化する燐の分圧を低減する。
（２）レースウェイ内でのメタルの滞留時間を短縮する。
（３）燐を含有する鉱石に代え燐分の低い金属を供給する。
（４）燐を含有する炭材に代え燐分の少ない燃料ないし還元材を使用する。
（５）燐を含有する炭材の使用量を低減する。
【００２６】
しかしながら、これらの方策は、炭材充填層型の溶融還元炉による溶融還元の最大の利点である安価な原料の利用性を損なわないことを前提として、総合的に検討した結果、油分を含有する金属原料として、たとえば油分および金属分を含有する金属屑、スラジやダストまたはこれらに廃油、重油等の液体流動物を混合してスラリー状にしたものを炭材充填層に供給することにより、コストアップを招くことなく前記の（１）〜（５）の対策を全て充足できることを見いだした。
【００２７】
したがって、本発明では、前述のように少なくとも上下２段に設けた羽口から酸素含有熱風を吹き込むと共に、複数の羽口のうち最上段に位置する羽口または最上段羽口を包含する選択した羽口に配置したメインランスを用いて、粉粒状の金属酸化物原料、たとえば酸化鉄を含有する粉粒状の鉱石類（酸化鉄を含有するスラジやダストも含む）を炭材充填層中に吹き込み、さらに、複数の羽口のうち最上段羽口の位置および／または最上段羽口より下部の位置にサブランスを用いて、前記炭材充填層内に油分と金属分を含有するスラリー状含油金属原料を吹き込むものである。
【００２８】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて詳細に説明する。
図１に、炭材充填層型の溶融還元炉１を用いて溶融金属として溶銑を製造する場合を示しており、炉体の構造自体は図２に示した従来の場合と同様である。溶融還元炉１は、高価な電力あるいは強粘結炭を使用することなく、比較的安価な弱粘結炭または非粘結炭から製造したコークスを使用する利点を有するので、ますますエネルギーコストの上昇が危惧される今後の溶融金属の製造装置として有望である。
【００２９】
溶融還元炉１は、図１に示すように炉腹下部に上段羽口４と下段羽口５を備え、炉上方の炭材供給装置６から炭素系固体還材として代表的な炭材として塊状のコークスが供給され、炉内に炭材充填層19を形成しつつ炉内を降下する。また、高温送風装置２から酸素含有熱風（高温空気あるいは高温酸素富化空気）が供給され、高温送風分配装置３により分配した熱風を高温送風供給管20を介して上下２段の羽口４、５に供給し、羽口４、５からそれぞれ炉内に吹き込まれる。このようにして上段羽口４および下段羽口５から炉内に吹き込まれた熱風は、高温のレースウェイ18を形成する。
【００３０】
粉粒状鉱石類供給装置７に貯蔵されている粉粒状鉄鉱石類（酸化鉄原料）とフラックス供給装置８に貯蔵されている造滓材としての粉粒状のフラックスは、粉粒体吹き込み装置９から空気等のキャリアガスと共に粉粒体輸送管10を経て、上段羽口４内に配置したメインランス14から炉内に吹き込まれる。メインランス14より炉内に吹き込まれた酸化鉄原料及びフラックスは、上段羽口４の前方に形成される高温のレースウェイ18の空間で溶融すると共に、酸化鉄原料中の燐が高温のレースウェイ内で気化する。
【００３１】
一方、含油金属原料供給装置16内の油分および鉄分（金属鉄）を含有するスラリー状含油金属鉄原料は、含油金属原料供給装置16の作動によりスラリー輸送管17を介して上段羽口４および／または下段羽口５に、それぞれ配置されたサブランス15から炉内に吹き込まれる。油分および鉄分を含有するスラリー状含油金属鉄原料は、スラリー輸送管17による輸送可能な液体流動物であることが必要であり、含油金属鉄原料が元々スラリー輸送管17により輸送可能な流動性を有する場合には、そのまま使用することができる。油を含有する金属屑としては、金属切削屑、金属の機械加工屑あるいはスクラップ解体屑として市場に安価で多量に存在するものを使用する。
【００３２】
しかしながら、油分の付着した繊維状金属鉄屑、粉状金属鉄屑、金属鉄含有スラジまたは金属鉄含有ダストは、たとえ油分を含んでいても、通常はそのままではスラリー輸送管17により輸送可能なほどの流動性がない場合が多い。このような場合には、含油金属鉄原料に廃油や重油等の可燃性流動物（液体）を加えることにより、輸送性を高めたスラリー状に調整してスラリー輸送管17による輸送を可能にして使用することになる。このようにして廃油等の可燃性流動物を加えてスラリー状に調整した油分を含有する繊維状金属鉄屑、粉状金属鉄屑、金属鉄含有スラジまたは金属鉄含有ダストから選択した１種または２種以上の含油金属鉄原料が、サブランス15から炉内に吹き込まれる。なお、上段羽口４と下段羽口５の間にサブランス15を配置し、ここから含油金属鉄原料を供給することも可能である。要は、上段羽口４の位置または上段羽口４より下部の位置に含油金属鉄原料を吹き込むことが重要である。
【００３３】
前述のようにしてメインランス14より炉内に吹き込まれた酸化鉄原料及びフラックスが、上段羽口４の前方に形成される高温のレースウェイ18の空間で溶融すると共に、酸化鉄原料中の燐および還元材である炭材に含有される燐分は、高温のレースウェイ内で気化する。このような状態で、上段羽口４に配置したサブランス15から炉内に供給されたスラリー状含油金属鉄原料のうち、廃油等の液体成分はレースウェイ内で膨張し、さらには炉内での油分の燃焼により燃焼ガスとなり、ガス容積が増加する。急激な体積膨張によってガス中に気化状態で存在する燐は、レースウェイ18内から炉の内部に深く押し出され、炉内を速やかに上昇する。このため、燐とメタルとの接触時間が短くなり、燐がメタルに移行するのを抑制することができる。
【００３４】
さらに、油分の燃焼による急激なガス容積の増大は、ガス相中の燐分圧の低下をもたらすので、ガス相と溶融メタルが接触している場合でも、ガス相中から燐が溶融メタルに移行するのを抑制することにもなる。そのため、従来のように溶融メタルが気化した燐を吸収することなく炉内を降下し、溶銑中の燐濃度の低減が達成できる。また、サブランス15から炉内に供給された液体成分のうち、廃油等の燃焼成分は、燃料および還元剤として作用するので、使用する炭材の量を減らすことができ、炭材に起因する燐のインプット量を減らすことができる。
【００３５】
サブランス15から炉内に供給された物質のうち金属鉄分は、そのままメタルに移行するが、燐含有量の低い金属鉄原料を選択すれば、メタルの燐を低減できるうえ、同量の溶銑を生産する場合の酸化鉄原料の量を低減できるから、鉱石に起因する燐のインプットを低下することになる。また、金属鉄は鉱石のように還元を要しないので、還元剤としての炭材を減らすことができ、このことによって炭材起因の燐インプット量を減らすことにもなる。
【００３６】
本発明では、前述のように安価に入手できる油を含んだ金属スラジ、金属ダストや有用なＮｉ、Ｍｏ等を含んだ金属屑等の含油金属原料を油と共に有効に利用することができる。サブランス15から炉内の炭材充填層19内に供給された含油金属鉄原料中の油分は、気化し、炉内の 200℃以上の高温部で分解され、上下の羽口４、５のレースウェイ18で燃焼し、また、未燃焼分があったとしても、供給位置の上部に存在する炭材充填層19において分解するため、排ガス処理装置13等の排ガス系を汚染したり、詰まりを生じるという問題がなくなる。また、サブランス15から炉内にスラリー状で供給しても、高炉のように炉内圧力が高くないために、サブランス15の先端でのスラッギングが生ぜず、安定した炉内への供給を可能にする。
【００３７】
なお、前述の通り上下２段に配設された羽口４、５のうち、最上段に位置する羽口４に酸化鉄原料粉を吹き込むのが有利である。これは、最上段に位置する羽口４から酸素含有熱風と一緒に吹き込まれた酸化鉄原料粉が、炉内で高温下のレースウェイ18で溶融還元され、気化した燐が速やかに炉の上方に上昇するので復燐することなく炉外に排出されるからである。そして、残りの酸化鉄原料は、炉内を降下する間に下段側に配設された羽口５から吹き込まれる酸素含有熱風、炉内の炭材や油分の燃焼により生じた還元生ガスにより溶融還元が促進される。サブランス15から吹き込むスラリー状含油金属原料の吹き込み量は、炉高、羽口数（３段以上も可能）、金属酸化物原料等の操業上の諸条件を考慮して定めることになる。
【００３８】
また、下段羽口５に配置されたサブランス15から供給されたスラリー状金属鉄原料の油分は、燃焼することにより炉下部での炭材の消費量が減少するばかりでなく、下降する酸化鉄原料中の酸化鉄は、油分の燃焼により発生する還元ガスにより十分に還元される。炭材として炉内に装入したコークスのみの使用では、コークス燃焼後に灰分が炉芯に溜まり操業上の支障となるが、油分の燃焼は灰分を生じないので、その代替分だけ、前記炉芯への灰分の堆積が緩和され、炉操業の安定化に寄与することになる。
【００３９】
前述のように本発明では、上下の羽口４、５からの酸素含有熱風およびメインランス14からの酸化鉄原料に加え、炭材充填層内にサブランス15からスラリー状含油金属原料を吹き込むようにしたので、油の燃焼により上段羽口４の前方に形成されるレースウェイの内部で酸化鉄原料の気化脱燐が円滑に行われるようになる。補助燃料となる油としては、廃油、重油等の液体燃料が使用でき、また、スラリー状含油金属原料は配管輸送が可能で、レースウェイ内で燃焼できる流動状であればよい。
【００４０】
以下、本発明の実施の態様を具体的に説明する。
図１に示すように炭材充填層型の溶融還元炉１を用いてクロムを含有した銑鉄の製造試験を実施した。
試験に供した溶融還元炉の仕様は、次の通りである。
炉内径：４ｍφ
炉高 ：１４ｍ
充填層高さ：１１ｍ
充填コークス粒子径：10〜30ｍｍ、平均１５ｍｍ
上下羽口間隔：２．５ｍ
羽口径：１００ｍｍ
羽口本数：上段４本、下段４本、計８本
羽口径：３０ｍｍ
メインランス：上段羽口に配置４本
サブランス：上段羽口に配置４本または下段羽口に配置４本、あるいは上段羽口に配置２本、下段羽口に配置２本、計４本
前記の溶融還元炉に炉頂より、炭材供給装置６を介して平均粒径１５ｍｍのコークスを装入し、高さ１１ｍの充填層を形成した。そして、上段羽口４に配置したメインランスより、酸化鉄原料として鉄鉱石粉（平均値Ｃ：4.7 重量％、T.Fe：62.4重量％、FeO :31.8 重量％、SiO₂:0.8重量％、T.Cr：6.2 重量％、MnO :4.0重量％、Al₂O₃:1.1 重量％、その他の酸化物20.6重量％）を１０t/hr、CaO 、SiO₂からなる造滓材（フラックス）を１．７t/hrを供給した。含油金属鉄原料として表１に示す化学組成のステンレスコイルのグラインダ屑（ＣＧＲ）、エッチングＮｉスラジ（粉状）、含Ｎｉスラジ（粉末）、Ｎｉ触媒Ａ（粉状）またはＮｉ触媒Ｂ（含油粉状）を用い、輸送媒体として表２に示すような化学組成の廃油を加えてスラリー状に調整し、含油金属鉄原料とした。このようにしてスラリー状にした含油金属鉄含有原料を、含油金属原料供給装置からスラリー輸送管を経由してサブランスから炉内に吹き込んだ。
【００４１】
【表１】

【００４２】
【表２】

【００４３】
その際、使用した搬送気体は、高温送風装置２で製造した温度 800℃の酸素富化空気および高温空気であり、高温送風分配装置３を介して、それぞれの高温送風供給管20を経て上段羽口４に酸素富化空気（Ｏ₂ ：41％）を、また下段羽口５に空気（Ｏ₂ ：38％）を炉内に吹き込んだところ、順調に操業を行うことができた。
【００４４】
操業条件を表３および表４に、また操業結果を表５に示す。なお、表３、表４および表５には、従来方法に相当するスラリー状含油金属鉄原料を吹き込まない比較例と、スラリー状含油金属鉄原料を吹き込む本発明に係る溶銑の製造方法を用いた実施例１〜11の場合とを比較して示した。表３には、上段羽口および下段羽口の各送風量、送風温度、送風中の酸素ガス濃度と上段羽口に配置したメインランスからの酸化鉄原料の吹き込み量を示し、また表４には、サブランスから吹き込むスラリー状含油金属鉄原料の種類、上下の羽口への配分割合、金属鉄原料の吹き込み量と廃油吹き込み量を示す。表４に示すように上段羽口４と下段羽口５とに吹き込む含油金属鉄原料の割合は、それぞれ上下等分の50％にする場合、上段羽口４に100 ％にする場合および下段羽口５に100 ％にする場合の３水準とした。さらに表５には、操業成績としてコークス比、スラグ比、溶銑温度およびメタル（溶銑）の生産量を示している。
【００４５】
【表３】

【００４６】
【表４】

【００４７】
【表５】

【００４８】
表３、表４および表５から明らかなように、本発明例１〜11では、サブランスからのスラリー状含油金属鉄原料の供給により、比較例よりも溶銑中の燐濃度が概ね低下しており、溶銑の脱燐が円滑に行われたことを示している。また、コークス比も概ね低減し、油分が燃料コークスの代替に一役かっており、メタルの生産量も増加傾向を示していることが分かる。
【００４９】
溶融還元炉の炉複部に配置するサブランスの高さ位置を変えてステンレスのグラインダ屑に廃油を流動媒体として炉内に吹き込んだときの、上段羽口からのサブランス位置（ｍ）と溶銑中の燐濃度（％) との関係を図３に、また上段羽口からのサブランス位置（ｍ）と炉頂排ガス中の炭化水素濃度（％）との関係を図４に示す。図３より明らかなようにスラリー状含油金属鉄原料を供給するサブランスの位置を上段羽口より下部にするにつれて溶銑中の燐濃度を低くすることができる。そして下段羽口にサブランスを配置してスラリー状含油金属鉄原料を供給すると、溶銑中の燐濃度低下効果が最も大きくなる。また、図４からスラリー状含油金属鉄原料を供給するサブランスの位置を上段羽口より下部にすることにより、炉頂排ガス中の炭化水素濃度を低減することができることが分かる。
【００５０】
【発明の効果】
以上説明したように本発明によれば、炭材充填層型の溶融還元炉を用いて従来より処理に困っていた安価な含油金属原料が、乾燥等の前処理することなく油と共に有効に処理でき、社会環境上の効果も得られる。炉内での気化脱燐の促進により、燐含有量の低い溶融金属を安価に、かつ容易に大量生産することが可能になる。また、含油金属原料の金属は、還元熱を必要としないため燃料費を大きくすることなく、溶融金属を大量に生産することが可能になる。
【００５１】
本発明が対象とする溶融金属としては、前述に例示した溶銑（すなわち、溶融Fe-C系合金や、これにさらにCrやNi等の他の元素を含有するもの）の他にも、炭素還元によって溶融還元して製造する金属・合金であれば特に限定するものではない。
含油金属原料の油分や輸送媒体として用いる油分などの可燃性燃料が炭材燃料の一部代替となるため、炭材を節減できるばかりでなく、炭材中の燐等の不純物の装入量を抑えることが可能である。さらに、含油金属原料をスラリー状にして輸送するので輸送管の磨耗を軽減することができると共に、油分等の可燃性燃料の燃焼により、排ガス系の詰まりを防止することができる。
【図面の簡単な説明】
【図１】本発明に係るスラリー状含油金属鉄原料を吹き込む炭材充填層型の溶融還元炉を付帯装置と共に示す概略縦断面図である。
【図２】従来に係る炭材充填層型の溶融還元炉を示す概略縦断面図である。
【図３】上段羽口からのサブランス位置までの距離（ｍ）と溶銑中の燐濃度（％）との関係を示すグラフである。
【図４】上段羽口からのサブランス位置までの距離（ｍ）と炉頂排ガス中の燐濃度（％）との関係を示すグラフである。
【符号の説明】
１ 溶融還元炉
２ 高温送風装置
３ 高温送風分配装置
４ 上段羽口
５ 下段羽口
６ 炭材供給装置
７ 粉粒状鉱石類供給装置
８ フラックス供給装置
９ 粉粒体吹き込み装置
10 粉粒体輸送管
11 出滓口
12 出銑口
13 排ガス処理装置
14 メインランス
15 サブランス
16 含油金属原料供給装置
17 スラリー輸送管
18 レースウェイ
19 炭材充填層
20 高温送風供給管[0001]
BACKGROUND OF THE INVENTION
The present invention provides a solid layer of a carbon-based solid reducing agent formed in a smelting reduction furnace, and blows oxygen-containing hot air from a plurality of tuyere disposed at least in two upper and lower stages in the lower part of the furnace. From the selected tuyere including the upper tuyere or the upper tuyere, a granular metal oxide raw material is blown into the packed bed, and the metal oxide raw material is melt-reduced to obtain a molten metal In particular, an object of the present invention is to produce a molten metal having a low phosphorus content in a smelting reduction furnace.
[0002]
[Prior art]
Generally, as a molten metal, for example, in order to produce a large amount of hot metal, a blast furnace that requires a massive raw material is often used. However, due to recent raw material circumstances, ores containing iron oxide or various metal oxides are reduced in the number of lumps and increased in the number of powders or small particles, and the tendency is expected to increase more and more. It is done. For this reason, normally, after making a granular iron ore into a massive sintered ore with a DL type sintering machine, it is charged into a blast furnace. However, the sintering machine that sinters the powdered iron ore not only requires a huge investment in equipment, but it also takes a lot of money to maintain and manage the operation of the sintering machine, The cost of pig iron produced in a blast furnace is raised.
[0003]
Therefore, in the production of hot metal using a blast furnace, investigations have been made to blow powder ore from the tuyere to reduce costs. However, as the amount of powder ore blown is increased, Since it adheres to the tip of the mouth and closes the inlet of the tuyere, it is difficult to blow a large amount of powdered ore, and the fact is that it is not a fundamental solution.
[0004]
On the other hand, to produce low phosphorus steel or low phosphorus steel, low phosphorus coke is used during hot metal production in a blast furnace, or dephosphorization treatment is performed during hot metal pretreatment to reduce the blowing load of the converter. Alternatively, dephosphorization is generally performed in the steel making process. Among these processes, in order to charge low phosphorus coke into a blast furnace, for example, low phosphorus coke is produced by the conventional technique described in Japanese Patent Laid-Open No. 52-105920, and this is used in a blast furnace. Although it is conceivable to reduce the content, coke produced by this method is expensive and disadvantageous from an economic point of view.
[0005]
In addition, dephosphorization in the hot metal pretreatment requires a new pretreatment facility, and is accompanied by problems such as shortening the refractory life of the blast furnace discharge and the topped car. Pretreatment of hot metal and dephosphorization treatment in the steelmaking process impose various burdens on the next step of converter blowing and desulfurization outside the furnace, which is uneconomical when viewed as a total process of ironmaking or steelmaking. Furthermore, in order to aim at low phosphorus steel, there is an iron manufacturing technique called electrolysis, but the energy cost is enormous and it is not suitable for mass production.
[0006]
Therefore, in recent years, as a method for mass-producing low phosphorus soot having a phosphorus content of 0.05% by weight or less without using expensive carbon materials such as low phosphorus coke, Japanese Patent Laid-Open Nos. 57-198205 and 58 Many publications such as the publication No. -77548 propose a method for producing hot metal using a carbon material packed bed type smelting reduction furnace.
As shown in FIG. 2, a carbon material packed bed type smelting reduction furnace 1 includes an upper tuyere 4 and a lower tuyere 5 and a carbon-based solid reducing material (carbonaceous material such as coke) from a charcoal supply device 6 above the furnace. ) Is supplied to form a charcoal packed bed 19 in the furnace. Then, hot air is supplied from the high temperature air blower 2, and the hot air is distributed to the upper and lower two-stage tuyere 4 and 5 by the high temperature air blower distributor 3. The granular ore containing iron oxide stored in the granular ore supply device 7 and the granular flux stored in the flux supply device 8 are passed through the granular material transport pipe 10 by the granular material blowing device 9. The main lance 14 disposed in the upper tuyere 4 is blown into the furnace together with a carrier gas such as air.
[0007]
The granular iron ore (iron oxide raw material) and granular flux blown into the furnace from the main lance 14 are heated by hot air (high-temperature air or oxygen-enriched high-temperature air) blown into the furnace. It melts in the space of the raceway 18 formed in front of. This molten material is reduced while dropping to the lower tuyere 5 and stays in the hearth as molten iron and slag, and the slag is discharged from the outlet 11 and the molten iron from the outlet 12. At that time, the gas discharged from the top of the smelting reduction furnace 1 is processed by the exhaust gas processing device 13.
[0008]
Since all the carbonaceous materials charged from the top of the furnace pass through a high temperature region of 1700 ° C. or higher, the applicant of the present application includes, for example, calcium phosphate Ca in the carbonaceous materials such as coke charged in the furnace. _Three P ₂ O _Three It was thought that phosphorus existing as is dephosphorylated by a chemical reaction described by the following chemical reaction formulas (1), (2), and (3).
(A) Phosphorus in coke is reduced by the following reaction in the high-temperature raceway portion.
[0009]
Ca _Three P ₂ O ₈ + 5C → 3CaO + 2P + 5CO (1)
In addition, SiO ₂ If present, the reduction of the solid reducing agent from calcium phosphate with carbon C and gas CO is facilitated. It is because the reduction of phosphorus in the coke is SiO ₂ This is because the next chemical reaction proceeds when performed in a high concentration region.

This reaction occurs and dephosphorization is promoted.
[0010]
Therefore, when charging the iron oxide raw material consisting of granular ore containing iron oxide (including sludge and dust) from the upper tuyere, the SiO in the iron oxide raw material ₂ By increasing the concentration, SiO in front of the upper tuyere ₂ The dephosphorization reaction is further promoted by increasing the concentration and causing the reactions of the chemical reaction formulas (2) and (3). The reduced phosphorus rises in the furnace together with the gas in the furnace, but partly adheres to dust etc. as the temperature decreases, and partly PN, PS, PO, PO ₂ As a result, the phosphorus concentration in the coke at the bottom of the raceway decreases.
(B) Phosphorus contained in the iron oxide raw material (ores) is reduced by the following chemical reaction formula (4) in the vicinity of the raceway formed at the tip of the tuyere. As a result, the phosphorous concentration of this material will decrease.
[0011]
2Fe _Three (PO _Four ) ₂ + 16CO → 3Fe ₂ P + P + 16CO ₂ ···(Four)
That is, the iron oxide raw material blown from the tuyere melts in the raceway part, and some phosphorus rises in the furnace due to the reaction of the chemical reaction formula (4), and the melt is reduced while dripping between cokes. It moves to the lower part of the furnace and becomes pig iron. At that time, since the phosphorus concentration in the coke is reduced by the reaction of the chemical reaction formula (1), the amount of the molten material that absorbs the phosphorus in the coke during dripping is small, and the phosphorus concentration in the hot metal is low. Become. When all the carbon material charged from the top of the furnace passes through the region of 1700 ° C or higher in the carbon material packed bed, the temperature is sufficiently high in the raceway part where phosphorus and iron oxide coexist, so the gaseous phosphorus quickly As the temperature rises in the furnace and the melt has a low viscosity, it drops quickly, so that there is almost no phosphorus trap in the hot metal.
[0012]
In addition, since the heat transfer to the center of each particle | grain is so fine that the particle size of the iron oxide raw material which blows in is fine, it is easy to heat up in a short time, and reaction of the said Chemical Reaction Formula (4) is smoother. Done. In addition, since the viscosity becomes smaller as the temperature is higher, the coexistence time of phosphorus and hot metal becomes shorter, so that the phosphorus concentration in the hot metal decreases. Furthermore, since the iron oxide blown into the raceway is melted and reduced by an endothermic reaction, it acts in the direction of lowering the coke temperature. Therefore, use of iron oxide with less impurities as the blown iron oxide reduces the wasteful heat for raising the temperature of the impurity or uses iron oxide with a small endothermic amount to promote a decrease in the phosphorus concentration in the hot metal. It is also possible. The phosphorus dephosphorized from the iron oxide raw material (ores) described in (B) also partially adheres to dust, etc. as the temperature decreases, and partly P 2, N 2, PS, PO, PO ₂ It becomes a compound such as, and then escapes from the top of the furnace and is removed.
[0013]
However, the smelting region in the smelting reduction furnace of the carbonaceous material packed bed type mainly consists of the raceway space and the portion where the melt below it drips, and most of the reaction in this smelting region is an endothermic reaction. In order to compensate for this heat, it was necessary to burn the carbonaceous material at the lower tuyere and compensate with the amount of blast heat. In addition, when a large amount of iron oxide powder is blown from the tuyere to increase the production volume in this furnace, a large endothermic reaction occurs in the raceway section, and the temperature around the raceway becomes 1700 ° C or lower, The phosphorus concentration inside increases. Therefore, it was necessary to compensate for heat by burning a large amount of carbonaceous material.
[0014]
Furthermore, if a large amount of carbonaceous coke is burned at the lower tuyere, the lowering speed of the charcoal between the upper and lower tuyere becomes faster and the residence time between the upper and lower tuyere of the melt becomes shorter. The body dripping. In order to secure the residence time between the upper and lower tuyere and proceed with the reduction, the distance between the upper and lower tuyere has to be sufficiently long, and the furnace height has to be increased in terms of equipment. In other words, in order to sufficiently vaporize phosphorus in the coke in this carbon material packed bed type smelting reduction furnace, it is necessary to use a high furnace with high equipment cost and to use a large amount of expensive carbon material. There was a problem.
[0015]
Therefore, the applicant of the present invention has disclosed, as a method capable of mass-producing low phosphorus with a phosphorus content of 0.05% or less at low cost, taking advantage of the characteristics of the carbon material packed bed smelting reduction furnace and Japanese Patent Laid-Open No. 5-9527. A method disclosed in Japanese Laid-Open Patent Application No. 5-475549 was proposed. This is because, unlike a blast furnace, a soot-type smelting reduction furnace is preferable for the production of low phosphorus because a so-called softened fusion body is not formed in the furnace and phosphorus does not circulate in the furnace. That is, as clarified in the above publication, vapor dephosphorization is possible by adjusting the furnace temperature to a high temperature. Thus, the carbon material packed bed smelting reduction furnace proposed by the present applicant not only solves the problem of depletion of energy sources in the future, but is also suitable for producing pig iron with a low phosphorus content.
[0016]
However, the smelting methods using the carbon material packed bed type smelting reduction furnaces proposed so far still have problems from the viewpoint of low phosphorus production. That is, in the prior art disclosed in JP-A-5-9527, an iron oxide raw material to be blown into the upper tuyere needs to contain 20% or more of FeO and disclosed in JP-A-5-475549. The prior art still requires a metal oxide in which vaporized phosphorus is aggregated as an iron oxide raw material blown from the tuyere. Such iron oxide raw materials are not common as metal oxide ores. Therefore, these smelting reduction processes have a weak point that the selection range of iron oxide raw materials is narrow and can be used only in limited cases. there were.
[0017]
When the specific iron oxide raw material as described above cannot be used, the phosphorus in the iron oxide raw material blown from the tuyere provided in the conventional smelting reduction furnace is vaporized in the high-temperature raceway. Is melted in a state where it is not sufficiently dispersed, so that melting and reduction proceed inside the raceway. For this reason, phosphorus gas is absorbed in the produced metal, and as a result, it is difficult to produce a desired low phosphorus content. Thus, the smelting method using the carbon material packed bed type smelting reduction furnace proposed so far still has problems from the viewpoint of low phosphorus production.
[0018]
[Problems to be solved by the invention]
Metal scrap containing metal, metal sludge, metal dust, etc. contain Ni, Mo, etc. useful as metal raw materials, and can be obtained at low cost, and their effective use has been desired in the past. . However, when dissolved and used in an electric furnace, converter, etc., there is a problem that the oil component is vaporized and clogs the exhaust gas system. In addition, if the gas is transported to the tuyere of the blast furnace and blown, the oil component is highly viscous, so that it adheres to the inside of the transfer pipe and the blow pipe and is clogged, making it difficult to blow for a long time. On the other hand, when trying to blow in the form of a slurry, the pressure inside the furnace is high, so that the raw material powder adheres at the tip of the blow pipe, and this gradually grows to cause slagging, which also prevents stable blowing Was not put into practical use. Therefore, at present, oil-impregnated metal scraps and the like are used after being degreased and washed in advance, so that the advantage of an inexpensive metal raw material has been impaired by the processing cost.
[0019]
Carbonaceous material packed bed type smelting reduction furnace is a metal oxide raw material, for example, iron ore as an iron oxide raw material, as well as various sludges and dusts generated from steelworks such as sludge and dust generated during converter blowing. In addition, there can be used oil-containing metal raw materials such as metal scrap containing oil. Furthermore, it is expected to be a hot metal production furnace in the future where energy costs are likely to rise due to the use of relatively inexpensive weak or non-caking coal without using expensive electric power or strong caking coal. it can. The present invention has been made in view of such circumstances, and without using an expensive carbon material such as low phosphorus coke, a molten metal having a low phosphorus content such as a low phosphorus hot metal having a phosphorus content of 0.05% by weight or less. It is an object of the present invention to provide a method for producing molten metal using a carbon material packed bed type smelting reduction furnace capable of mass production at low cost without depending on the quality of raw ores.
[0020]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present inventors have conducted intensive research and made use of the characteristics of a smelting reduction furnace of a carbonaceous material packed bed type that is originally advantageous for dephosphorization, so that the fiber or powder containing oil is contained. Focusing on the use of metal scrap, metal-containing sludge, or metal-containing dust, the result of repeated various experiments. In other words, liquid fluid such as waste oil was added to the fibrous or powdery metal scrap or metal-containing sludge or metal-containing dust directly blown into the smelting reduction furnace in which the packed layer of carbon-based solid reducing material was formed. Various slurry-like oil-containing metal raw materials were used, and these were singly or appropriately combined to promote vaporization and dephosphorization in the furnace, thereby completing the present invention.
[0021]
That is, according to the present invention, a packed layer of a carbon-based solid reducing agent is formed in a smelting reduction furnace, and oxygen-containing hot air is blown into the lower part of the furnace from a plurality of tuyere arranged at least in two upper and lower stages. And a main lance arranged in the selected tuyere including the tuyere located in the uppermost stage or the uppermost tuyere among the plurality of tuyere, and using the main lance disposed in the packed bed In the method for producing a molten metal using a carbon material packed bed type smelting reduction furnace that blows and melts and reduces the metal oxide raw material to produce a molten metal, the position of the uppermost tuyere and / or the highest of the plurality of tuyere Molten metal by a carbon-filled bed type smelting reduction furnace characterized in that a slurry-like oil-containing metal raw material containing oil and metal is blown into the packed bed using a sub lance arranged at a position below the upper tuyere. In the manufacturing method That.
[0022]
In the present invention according to claim 2, the slurry-like oil-containing metal raw material containing an oil and a metal is one or more selected from fibrous metal waste, powder metal waste, metal-containing sludge or metal-containing dust containing oil. It is a slurry-like metal raw material which added the liquid fluid to 2 or more types, The manufacturing method of the molten metal by the carbonaceous material packed bed type | mold smelting reduction furnace of Claim 1 characterized by the above-mentioned.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Conventionally, a packed bed of carbon-based solid reducing material (carbon material) is formed, and a plurality of tuyere provided in at least two upper and lower stages for blowing high-temperature oxygen-containing hot air (air or oxygen-enriched air) into the lower part of the furnace belly. Using a carbonaceous material packed bed type smelting reduction furnace, powdered ore containing iron oxide is blown into the packed bed as iron oxide raw material together with hot air containing oxygen from the tuyere, and iron oxide in the iron oxide raw material The hot metal was produced by melting and reducing. However, as described above, in the conventional operation, phosphorus in the iron oxide raw material blown from the tuyere is vaporized in the high-temperature raceway, but there is metal generated by smelting reduction inside the raceway, so vaporization occurs. Most of the phosphorous dissolved in the metal, and the dephosphorization of the hot metal was insufficient.
[0024]
Another source of phosphorus that migrates into the metal is the phosphorus contained in the carbonaceous material, which is a reducing material. Phosphorus in the carbonaceous material is dissolved in the slag by direct contact with the metal or once with the ash content of the carbonaceous material. In addition, it moves into the metal due to the reaction between the slag and the metal. After elucidating such a phenomenon of phosphorus migration, the present inventors have come to realize that the following measures are effective in reducing the phosphorus content in the metal.
[0025]
(1) Reduce the partial pressure of phosphorus vaporized inside the raceway.
(2) Reduce metal residence time in the raceway.
(3) Supply metal with low phosphorus content instead of ore containing phosphorus.
(4) Use fuel or reducing material with low phosphorus instead of carbon containing phosphorus.
(5) To reduce the amount of carbon material containing phosphorus.
[0026]
However, these measures contain oil as a result of a comprehensive study on the premise that the availability of inexpensive raw materials, which is the greatest advantage of smelting reduction with a carbon material packed bed type smelting reduction furnace, is not impaired. Costs can be achieved by supplying metal raw materials such as oil and metal scraps containing metal, sludge and dust, or slurries mixed with liquid fluids such as waste oil and heavy oil to the carbon material packed bed. It has been found that all the measures (1) to (5) can be satisfied without incurring an increase.
[0027]
Therefore, in the present invention, as described above, oxygen-containing hot air is blown from the tuyere provided at least in the upper and lower stages, and the tuyere located at the uppermost stage or the uppermost tuyere is selected among the plurality of tuyere Using a main lance placed at the tuyere, powdered metal oxide raw materials, for example, powdered ores containing iron oxide (including sludge and dust containing iron oxide) are blown into the carbon material packed bed Further, among the plurality of tuyere, a slurry-like oil-impregnated metal containing an oil component and a metal component in the carbonaceous material packed bed using a sub lance at the position of the uppermost tuyere and / or the position below the uppermost tuyere The raw material is blown.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a case where hot metal is produced as a molten metal using a carbon material packed bed type smelting reduction furnace 1, and the structure of the furnace body itself is the same as that of the conventional case shown in FIG. Since the smelting reduction furnace 1 has the advantage of using coke produced from relatively inexpensive weak or non-caking coal without using expensive electric power or strong caking coal, the energy cost is increasingly increased. It is promising as a future molten metal production equipment that is feared to rise.
[0029]
As shown in FIG. 1, the smelting reduction furnace 1 is provided with an upper tuyere 4 and a lower tuyere 5 at the lower part of the furnace belly. Coke is supplied, and the inside of the furnace is lowered while forming the carbonaceous material packed bed 19 in the furnace. Also, hot air containing oxygen (high-temperature air or high-temperature oxygen-enriched air) is supplied from the high-temperature air blower 2, and the hot air distributed by the high-temperature air distributor 3 is connected to the upper and lower tuyere 4 via the high-temperature air supply pipe 20 5 and blown into the furnace from the tuyere 4 and 5, respectively. The hot air thus blown into the furnace from the upper tuyere 4 and the lower tuyere 5 forms a high-temperature raceway 18.
[0030]
The granular iron ore (iron oxide raw material) stored in the granular ore supply device 7 and the granular flux as the fossil material stored in the flux supply device 8 are supplied from the granular material blowing device 9. Along with a carrier gas such as air, it is blown into the furnace through a main lance 14 disposed in the upper tuyere 4 through the granular material transport pipe 10. The iron oxide raw material and the flux blown into the furnace from the main lance 14 are melted in the space of the high temperature raceway 18 formed in front of the upper tuyere 4, and the phosphorus in the iron oxide raw material is the high temperature raceway. Vaporize within.
[0031]
On the other hand, the slurry-like oil-containing metal iron raw material containing oil and iron (metal iron) in the oil-containing metal raw material supply device 16 is supplied to the upper tuyere 4 and / or via the slurry transport pipe 17 by the operation of the oil-containing metal raw material supply device 16. Or, the lower tuyere 5 is blown into the furnace from the sublances 15 respectively arranged. The slurry-like oil-impregnated metallic iron raw material containing oil and iron must be a liquid fluid that can be transported by the slurry transport pipe 17, and the oil-impregnated metal iron raw material originally has fluidity that can be transported by the slurry transport pipe 17. If it has, it can be used as it is. As metal scraps containing oil, those which are present in the market at a low price and in large quantities as metal cutting scraps, metal machining scraps or scrap dismantling scraps are used.
[0032]
However, the fibrous metallic iron scraps, powdered metallic iron scraps, metallic iron-containing sludge or metallic iron-containing dust to which oil is adhered, even if they contain oil, are usually transported by the slurry transport pipe 17 as they are. In many cases, there is no fluidity. In such a case, by adding a flammable fluid (liquid) such as waste oil or heavy oil to the oil-impregnated metallic iron raw material, it is adjusted to a slurry with improved transportability and can be transported by the slurry transport pipe 17. Will be used. One kind selected from fibrous metallic iron scraps, powdered metallic iron scraps, metallic iron-containing sludges or metallic iron-containing dusts containing oil components adjusted to a slurry by adding a combustible fluid such as waste oil in this way Two or more oil-impregnated metallic iron raw materials are blown into the furnace from the sublance 15. In addition, it is also possible to arrange the sub lance 15 between the upper tuyere 4 and the lower tuyere 5 and supply oil-impregnated metallic iron raw material therefrom. In short, it is important to blow the oil-impregnated metallic iron raw material into the position of the upper tuyere 4 or the position below the upper tuyere 4.
[0033]
As described above, the iron oxide raw material and the flux blown into the furnace from the main lance 14 melt in the space of the high-temperature raceway 18 formed in front of the upper tuyere 4 and the phosphorus in the iron oxide raw material. And the phosphorus content contained in the carbonaceous material as the reducing material is vaporized in the high-temperature raceway. In such a state, liquid components such as waste oil out of the slurry-like oil-impregnated metallic iron raw material supplied into the furnace from the sublance 15 arranged in the upper tuyere 4 expands in the raceway, and further in the furnace. Combustion oil becomes combustion gas and gas volume increases. Phosphorus present in the gas in a vaporized state due to rapid volume expansion is pushed deeply into the furnace from the raceway 18 and quickly rises in the furnace. For this reason, the contact time of phosphorus and a metal becomes short, and it can suppress that phosphorus transfers to a metal.
[0034]
Furthermore, the sudden increase in gas volume due to the combustion of oil causes a decrease in the phosphorus partial pressure in the gas phase, so even if the gas phase is in contact with the molten metal, phosphorus moves from the gas phase to the molten metal. It will also be suppressed. Therefore, it is possible to lower the phosphorus concentration in the hot metal by lowering the inside of the furnace without absorbing phosphorus vaporized by the molten metal as in the prior art. Of the liquid components supplied from the sublance 15 into the furnace, combustion components such as waste oil act as a fuel and a reducing agent, so that the amount of carbon material used can be reduced, and phosphorous caused by the carbon material can be reduced. The amount of input can be reduced.
[0035]
Of the material supplied from the sublance 15 into the furnace, the metallic iron content is transferred to the metal as it is, but if a metallic iron raw material with a low phosphorus content is selected, the metallic phosphorus can be reduced and the same amount of hot metal can be produced. In this case, the amount of iron oxide raw material can be reduced, so that the input of phosphorus resulting from ore is reduced. Moreover, since iron does not require reduction like ore, the carbonaceous material as a reducing agent can be reduced, and this also reduces the amount of phosphorus input resulting from the carbonaceous material.
[0036]
In the present invention, oil-containing metal raw materials such as metal sludge containing oil that can be obtained at low cost, metal dust, metal scrap containing useful Ni, Mo and the like can be effectively used together with oil as described above. The oil in the oil-impregnated metallic iron raw material supplied from the sub lance 15 into the charcoal packed bed 19 in the furnace is vaporized and decomposed at a high temperature portion of 200 ° C. or more in the furnace, and the upper and lower tuyere 4, 5 races Even if there is an unburned portion combusted in the way 18, it is decomposed in the carbon material packed bed 19 existing at the upper part of the supply position, so that the exhaust gas system such as the exhaust gas treatment device 13 is contaminated or clogged. The problem of disappearing. Also, even if slurry is supplied from the sub lance 15 into the furnace, the pressure inside the furnace is not as high as in the blast furnace, so there is no slagging at the tip of the sub lance 15 and stable supply to the furnace is possible. To do.
[0037]
As described above, it is advantageous to blow the iron oxide raw material powder into the tuyere 4 located in the uppermost stage among the tuyere 4 and 5 arranged in the upper and lower two stages. This is because the iron oxide raw material powder blown together with the oxygen-containing hot air from the tuyere 4 located at the uppermost stage is smelted and reduced in the raceway 18 at a high temperature in the furnace, and the vaporized phosphorus is quickly moved up the furnace. This is because it is discharged to the outside of the furnace without being recovered. The remaining iron oxide raw material is melted by oxygen-containing hot air blown from the tuyere 5 disposed on the lower stage while descending the furnace, and reduced raw gas generated by combustion of the carbonaceous material and oil in the furnace. Reduction is promoted. The amount of slurry-like oil-impregnated metal raw material blown from the sublance 15 is determined in consideration of various operating conditions such as the furnace height, the number of tuyere (possible three or more stages), metal oxide raw materials and the like.
[0038]
Moreover, the oil content of the slurry-like metallic iron raw material supplied from the sublance 15 arranged in the lower tuyere 5 not only reduces the consumption of carbonaceous materials in the lower part of the furnace by burning, but also lowers the iron oxide raw material. The iron oxide inside is sufficiently reduced by the reducing gas generated by the combustion of the oil. When only coke charged into the furnace as a carbon material is used, ash accumulates in the furnace core after coke combustion, which hinders operation, but combustion of oil does not produce ash. As a result, the accumulation of ash in the soil will be alleviated, contributing to the stabilization of furnace operation.
[0039]
As described above, in the present invention, in addition to the oxygen-containing hot air from the upper and lower tuyere 4 and 5 and the iron oxide raw material from the main lance 14, the slurry-like oil-containing metal raw material is blown from the sub lance 15 into the carbon material packed bed. Therefore, the vaporization and dephosphorization of the iron oxide raw material is smoothly performed inside the raceway formed in front of the upper tuyere 4 by the combustion of oil. Liquid oil such as waste oil or heavy oil can be used as the auxiliary fuel, and the slurry-like oil-containing metal raw material may be fluidized so that it can be transported by piping and combusted in the raceway.
[0040]
Hereinafter, embodiments of the present invention will be specifically described.
As shown in FIG. 1, a production test of pig iron containing chromium was performed using a smelting reduction furnace 1 of a carbon material packed bed type.
The specifications of the smelting reduction furnace subjected to the test are as follows.
Furnace inner diameter: 4mφ
Furnace height: 14m
Packing bed height: 11m
Filled coke particle diameter: 10-30mm, average 15mm
Upper and lower tuyere spacing: 2.5m
Tuyere diameter: 100mm
Number of tuyere: 4 on top, 4 on bottom, 8 in total
Tuyere diameter: 30 mm
Main lance: 4 on the upper tuyere
Sublance: 4 in the upper tuyere, 4 in the lower tuyere, 2 in the upper tuyere, 2 in the lower tuyere, 4 in total
Coke having an average particle diameter of 15 mm was charged into the smelting reduction furnace from the top of the furnace through the carbon material supply device 6 to form a packed bed having a height of 11 m. And, from the main lance arranged at the upper tuyere 4, iron ore powder (average value C: 4.7 wt%, T.Fe: 62.4 wt%, FeO: 31.8 wt%, SiO2 as an iron oxide raw material) ₂ : 0.8 wt%, T.Cr: 6.2 wt%, MnO: 4.0 wt%, Al ₂ O _Three : 1.1 wt%, other oxide 20.6 wt%) 10t / hr, CaO, SiO ₂ A koji material (flux) consisting of 1.7 t / hr was supplied. Stainless steel coil grinder scrap (CGR), etching Ni sludge (powder), Ni-containing sludge (powder), Ni catalyst A (powder) or Ni catalyst B (oil-containing powder) having the chemical composition shown in Table 1 as the oil-impregnated metallic iron raw material The waste oil having a chemical composition as shown in Table 2 was added as a transport medium to prepare a slurry, which was used as an oil-containing metal iron raw material. The oil-containing metal iron-containing raw material thus made into a slurry was blown into the furnace from the sub lance via the slurry transport pipe from the oil-containing metal raw material supply device.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
At that time, the carrier gas used was oxygen-enriched air and high-temperature air at a temperature of 800 ° C. manufactured by the high-temperature air blower 2, and passed through the high-temperature air supply / distribution device 3 through the respective high-temperature air supply pipes 20. Oxygen-enriched air (O ₂ : 41%), and air (O ₂ : 38%) was blown into the furnace, and it was possible to operate smoothly.
[0044]
The operation conditions are shown in Tables 3 and 4, and the operation results are shown in Table 5. In Table 3, Table 4, and Table 5, the comparative example in which the slurry-like oil-containing metal iron raw material corresponding to the conventional method is not blown and the hot metal production method according to the present invention in which the slurry-like oil-containing metal iron raw material is blown are used. The results are shown in comparison with Examples 1 to 11. Table 3 shows the amount of air blown at the upper tuyere and the lower tuyere, the air temperature, the oxygen gas concentration during the blowing, and the amount of iron oxide raw material blown from the main lance placed at the upper tuyere. Indicates the type of slurry-like oil-impregnated metallic iron raw material blown from the sub lance, the distribution ratio to the upper and lower tuyere, the blowing amount of the metallic iron raw material and the waste oil blowing amount. As shown in Table 4, the ratio of the oil-impregnated metallic iron raw material blown into the upper tuyere 4 and the lower tuyere 5 is 50% in the upper and lower equal parts, 100% in the upper tuyere 4 and the lower tuyere Three levels for 100% in mouth 5. Further, Table 5 shows coke ratio, slag ratio, hot metal temperature and production amount of metal (hot metal) as operation results.
[0045]
[Table 3]

[0046]
[Table 4]

[0047]
[Table 5]

[0048]
As is apparent from Tables 3, 4 and 5, in Examples 1 to 11 of the present invention, the concentration of phosphorus in the hot metal was generally lower than that of the comparative example due to the supply of the slurry-like oil-containing metal iron raw material from the sublance. This shows that the hot metal dephosphorization was performed smoothly. In addition, the coke ratio has also been substantially reduced, and it can be seen that the oil content plays a role in substituting for fuel coke, and the metal production is also increasing.
[0049]
The position of the sublance from the upper tuyeres (m) and the position of the sublance located in the hot metal when the waste oil was blown into the furnace as stainless steel grinder scraps as a fluid medium by changing the height of the sublance placed in the multiple furnace sections of the smelting reduction furnace. FIG. 3 shows the relationship with the phosphorus concentration (%), and FIG. 4 shows the relationship between the sublance position (m) from the upper tuyere and the hydrocarbon concentration (%) in the furnace top exhaust gas. As apparent from FIG. 3, the phosphorus concentration in the hot metal can be lowered as the position of the sub lance for supplying the slurry-like oil-containing metallic iron raw material is made lower than the upper tuyere. And if a sublance is arrange | positioned in a lower tuyere and a slurry-like oil-impregnated metallic iron raw material is supplied, the phosphorus concentration reduction effect in hot metal will become the largest. Further, it can be seen from FIG. 4 that the hydrocarbon concentration in the exhaust gas at the top of the furnace can be reduced by setting the position of the sub lance for supplying the slurry-like oil-containing metal iron raw material to the lower part from the upper tuyere.
[0050]
【The invention's effect】
As described above, according to the present invention, an inexpensive oil-impregnated metal raw material that has been difficult to process using a carbon material packed bed type smelting reduction furnace can be effectively treated together with oil without pretreatment such as drying. Yes, and social effects can be obtained. By promoting vaporization and dephosphorization in the furnace, it becomes possible to easily mass-produce molten metal having a low phosphorus content at low cost. Moreover, since the metal of the oil-containing metal raw material does not require heat of reduction, it becomes possible to produce a large amount of molten metal without increasing the fuel cost.
[0051]
In addition to the hot metal exemplified above (that is, a molten Fe—C alloy, and further containing other elements such as Cr and Ni), the molten metal targeted by the present invention includes carbon reduction. There is no particular limitation as long as it is a metal / alloy produced by melting and reducing with a metal.
Combustible fuels such as oils of oil-impregnated metal raw materials and oils used as transport media can be used as a partial substitute for carbonaceous fuels, which not only saves carbonaceous materials but also reduces the amount of impurities such as phosphorus in the carbonaceous materials. It is possible to suppress. Furthermore, since the oil-containing metal raw material is transported in the form of a slurry, the wear of the transport pipe can be reduced, and the combustion of the combustible fuel such as oil can prevent clogging of the exhaust gas system.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a carbon material packed bed type smelting reduction furnace into which a slurry-like oil-impregnated metallic iron raw material according to the present invention is blown together with an auxiliary device.
FIG. 2 is a schematic longitudinal sectional view showing a conventional carbon material packed bed type smelting reduction furnace.
FIG. 3 is a graph showing the relationship between the distance (m) from the upper tuyere to the sublance position and the phosphorus concentration (%) in the hot metal.
FIG. 4 is a graph showing the relationship between the distance (m) from the upper tuyere to the sublance position and the phosphorus concentration (%) in the furnace top exhaust gas.
[Explanation of symbols]
1 Smelting reduction furnace
2 High temperature blower
3 High-temperature air distribution device
4 Upper tuyere
5 Lower tuyere
6 Charcoal material supply equipment
7 Powdered ore supply equipment
8 Flux supply device
9 Powder blower
10 Powder transport pipe
11 Outlet
12 Outlet
13 Exhaust gas treatment equipment
14 Main lance
15 Sublance
16 Oil-impregnated metal raw material supply equipment
17 Slurry transport pipe
18 Raceway
19 Charcoal packed bed
20 High temperature air supply pipe

Claims (2)

A packed layer of a carbon-based solid reducing agent is formed in the smelting reduction furnace, and oxygen-containing hot air is blown into the lower part of the furnace from at least two upper and lower tuyere, and the uppermost stage among the plurality of tuyere Using a main lance arranged in a selected tuyere including the tuyere located at the top or the uppermost tuyere, a granular metal oxide raw material is blown into the packed bed, and the metal oxide raw material is melted and reduced. In the method for producing a molten metal by using a carbon material packed bed type smelting reduction furnace for producing a molten metal, a sub lance arranged at the position of the uppermost tuyere and / or the position below the uppermost tuyere among the plurality of tuyere A molten metal-containing metal raw material containing an oil and a metal is blown into the packed bed, and a method for producing a molten metal using a carbonized packed bed type smelting reduction furnace. The slurry-like oil-containing metal raw material containing oil and metal contains a liquid fluid to one or more selected from fibrous metal waste containing oil, powder metal waste, metal-containing sludge or metal-containing dust. The method for producing a molten metal using a carbon material packed bed type smelting reduction furnace according to claim 1, wherein the raw material is a slurry-like metal raw material added.

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