JP3825272B2 - Method for producing sintered ore - Google Patents
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- JP3825272B2 JP3825272B2 JP2001108594A JP2001108594A JP3825272B2 JP 3825272 B2 JP3825272 B2 JP 3825272B2 JP 2001108594 A JP2001108594 A JP 2001108594A JP 2001108594 A JP2001108594 A JP 2001108594A JP 3825272 B2 JP3825272 B2 JP 3825272B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、焼結鉱の製造方法に関し、特に焼結鉱の品質を低下させることなく高生産性を達成し得る焼結用混合原料の添加剤に関するものである。
【０００２】
【従来の技術】
通常、高炉用原料である焼結鉱は、概略以下の工程で製造される。
【０００３】
まず、約１０ｍｍ以下の粒度の鉄鉱石粉に、同程度の粒度の焼結返鉱と、約３ｍｍ以下の粒度の珪石、石灰石、蛇紋岩などの副原料と、コークス粉、石炭粉などの固体燃料と、生石灰、消石灰等の凝集剤とを混合し、配合水を添加して混練に引き続いて疑似粒子化（粗い粒子を核として、その表面に微細な粒子を水の表面張力により付着させて形成した粒子群）した混合原料を、焼結機（たとえばドワイトロイド式焼結機）のパレット上に充填し、層頂部の混合原料中の固体燃料に着火する。着火後、下方に向けて空気を吸引しながら固体燃料を燃焼させてこの燃焼熱により充填した混合原料を焼結させて焼結ケーキとする過程で、混合原料を乾燥後、１１５０〜１２００℃へ加熱することにより、混合原料中の鉄鉱石と副原料とのスラグ反応により融液を生成させる。この融液により鉄鉱石粉の液相焼結が行われ、冷却後、この融液による鉄鉱石粉の結合により必要な焼結鉱の強度が得られる。
【０００４】
近年の鉄鉱石資源の変化に起因する鉄鉱石粉の微粉化傾向やリモナイト質鉱石の比率増加により、焼結原料の造粒性が悪化して擬似粒子の強度が低下して崩壊しやすくなり（特に、焼結中の充填層下部の水分凝縮帯（湿潤帯）においては、上部からの荷重も大きく擬似粒子が崩壊しやすい）、混合原料の通気性が悪化して焼結に要する時間が長くなり、焼結鉱の生産能率が低下する傾向にある。生産能率を維持ないし上昇させるためには、生石灰、消石灰等の凝集剤の添加量を増加させて擬似粒子を強化する方法が知られているが、生石灰、消石灰等のコストが高いため、焼結鉱の製造コストが高くなる問題がある。
【０００５】
生石灰、消石灰等を増量することなく安価に生産能率を維持ないし上昇する方法として、種々の方法が提案されている。
【０００６】
例えば、焼結原料に有空物質としてモミガラを添加して充填層の通気を改善する方法（特開昭５７−１４０８３５号公報）、疎充填材として発泡スチロールを添加して充填層の通気を改善する方法（特開昭５９−１６６６３２号公報）が提案されているが、モミガラや発泡スチロールの量を確保するのが困難なためいまだ実用化されていない。
【０００７】
また、焼結原料に古紙を０．０１〜３ｋｇ／焼結原料ｔ配合することにより、充填層を疎充填にするとともに、古紙で原料水分を吸収して焼結中の下層水分凝縮帯（湿潤帯）の水分を低下させ通気性を改善させるという提案（特開平７−１８３４４号公報）がなされているが、焼結原料に添加するのに適当な大きさに古紙を裁断する設備が別に必要であるためコスト低減効果が期待できないことに加え、古紙に吸収された水分はいずれ蒸発して下層に到達するため湿潤帯の水分が低下するとは考えがたく、通気性の改善効果も得られない可能性が高い。
【０００８】
また、焼結鉱配合原料中に３重量％以下の線状又は鱗片状鉄源を添加混合して、擬似粒子の強化と擬似粒子間の空間を適正に維持することにより、通気性の向上を図るとする提案（特開昭５７−７３１３５号公報）がなされているが、線状又は鱗片状鉄源としてスチールファイバー、古釘、線材、螺旋状の切削屑等を必要とし、量を確保することが困難なため実用化はなされていない。
【０００９】
さらに、リモナイト質鉄鉱石を焼結原料として使用するに際し、微量のＡｌ2Ｏ3を含有するＳｉＯ2粘土質物質と、ＭｇＯ−ＳｉＯ2含有鉱石のうち、１種又は２種以上を粗粒リモナイト鉱石に５〜１５重量％加え混合粉砕して粗粒リモナイト鉱石の表面をこれらの物質で覆うことにより、焼結に伴うリモナイト鉱石の急速溶融反応に起因する通気障害の防止を図るとする提案（特公昭５８−５５２２１号公報）があるが、事前にリモナイト質鉱石を微粉部分と粗粒部分に篩い分けする工程が余分に必要であるため設備コストが上昇する問題があることに加えて、湿潤帯における擬似粒子の崩壊を防止する効果が少ないため通気性の向上効果は限定されたものとなり、実用化はなされていない。
【００１０】
一方、生産能率を維持しつつ、生石灰（または消石灰）の使用量を削減して焼結鉱の製造コストを低減する方法についても、以下のように種々の提案がなされている。
【００１１】
例えば、配合槽を、外壁と内壁とからなる二重構造となし、外壁と内壁との間の空隙内に高温度の焼結クーラー排ガスを導き、配合槽内の焼結原料を予熱することによって生石灰の活性度を向上させることにより生石灰の使用原単位を低減する提案（特開平３−３１４２９号公報）がなされている。しかしながらこの方法では、配合槽を二重構造とする改造と、焼結クーラーから配合槽まで高温ガスを導く配管の新設を必要とすることから多額の改造費用を要する問題がある。
【００１２】
また、焼結原料をメラミン系、アクリル系、酢酸ビニル系などの樹脂溶液および水とともに造粒することにより、生石灰使用量の低減を図る提案（特開平３−１３４１２３号公報）がなされている。しかしこの方法では、高価な樹脂を用いるため生石灰使用量低減によるコストダウン効果が小さく、かつ焼結鉱品質に及ぼす影響が不明である。さらに、メラミン系樹脂など窒素を含有する樹脂を用いた場合には、焼結反応時の燃焼により窒素酸化物が発生するなど周辺環境への影響も懸念される。
【００１３】
また、焼結原料に生石灰および鋼ダライ粉などの微小な鋼屑を添加して造粒することにより、生石灰を単味配合して造粒する場合に比較して造粒物の粒径増加量が大きくなる結果、造粒物の落下強度の増加量も大きくなることを利用して生石灰使用量の低減を図る提案がなされている。しかしこの方法では、鋼ダライ粉などの鋼屑の量を確保することが困難であることに加え、鋼屑中のＺｎ、Ｐｂ等の不純物元素が焼結鉱に含有されて高炉に持ち込まれ、高炉操業に悪影響を及ぼす可能性があり、実際に適用することは難しい。
【００１４】
【発明が解決しようとする課題】
そこで、本発明の目的は、高価な生石灰等を増量することなく、かつ余分な設備を必要とすることなく、焼結層の通気性を改善し低コストで生産性を向上させる手段を提供することにある。
【００１５】
また、本発明の目的は、生産性を維持しつつ高価な生石灰等を低減してコストダウンを図る手段を提供することにある。
【００１６】
【課題を解決するための手段】
本発明者らは、焼結層の通気性を向上するためには、凝縮層における擬似粒子の崩壊を防止するため擬似粒子の強度を高めることが重要と考え、焼結混合原料の添加剤に注目し、添加剤の種類、組み合わせ、添加量等について種々検討を行った。その結果、添加剤として、有機繊維、粘土質物質、および有機粘着材を組み合わせて焼結混合原料へ同時に添加することにより上記課題を解決し得ることを見出した。
【００１７】
【００１８】
【００１９】
【００２０】
【００２１】
【００２２】
【００２３】
【００２４】
【００２５】
【００２６】
【００２７】
【００２８】
【００２９】
請求項１に記載の発明は、鉄鉱石粉と焼結返鉱と副原料と固体燃料とからなる焼結用混合原料１００質量部（乾量基準）に対して、古紙スラッジ ０．０１〜１．０質量部（乾量基準）を添加混合して常法により焼結することを特徴とする焼結鉱の製造方法である。
【００３０】
古紙スラッジは、古紙リサイクル工程において、アルカリ剤等を含む溶液を加えて古紙を離解した古紙懸濁液スラリーからパルプを取出した後の廃液中に含まれる浮遊物を分離回収したものである。したがって、古紙スラッジには、比較的短い有機繊維であるセルロース木質繊維が相当量含有され、古紙の無機充填剤および無機顔料であるベントナイト、タルク、石灰石、ドロマイト等由来の粘土質物質が濃縮され、さらに有機粘着材であるリグニンが含まれているので、これを用いることにより、下記の効果を得ることができる。
すなわち、焼結混合原料に有機繊維、粘土質物質、および有機粘着材を同時に添加すると、有機質繊維と粘土質物質は難水溶性であるが、有機粘着材は易水溶性であるので焼結混合原料の配合水に溶解し、有機質繊維と粘土質物質との接点に侵入してこれらを接合する。この接合物が焼結混合原料の鉱石や石灰石等の粒子間に入って粒子間の摩擦を大きくするため湿潤帯においても擬似粒子の崩壊が防止される。その結果、充填層の通気性が著しく改善され、焼結鉱製造の生産性が飛躍的に向上する。なお、有機繊維と有機粘着材は焼結時に燃焼して燃料として利用されるのでコークスや石炭などの固体燃料の配合量をも低減でき、粘土質物質は鉄鉱石等とスラグ反応して融液を生成し、焼結反応を促進する。
さらに、従来、古紙スラッジの大部分は、脱水又は乾燥して埋め立て処分や焼却処分されており、その処分に多大な経費を要していたが、大量に生産される焼結鉱の添加剤として用いることにより、資源およびエネルギーとして有効利用できるのみならず、環境汚染の防止にも寄与するものである。なお、従来技術の説明で述べた古紙そのものを用いる方法（特開平７−１８３４４号公報）の場合には、古紙が古紙スラッジとは異なり比較的長い繊維で構成されていることに加え、焼結原料に添加する際に繊維が離解されていないこと、粘土質物質の量が繊維の量に比べて非常に少ないこと等の理由から本発明の効果を奏し得ないものである。
そして、古紙スラッジの添加量が少なすぎると上記の効果が十分得られない一方、これらの添加量が多すぎると粘土質物質の添加量が多くなりすぎて高炉のスラグ量が増加するので上記範囲の添加量とすることが好ましい。
【００３１】
請求項２に記載の発明は、前記古紙スラッジを、前記混合原料に添加する配合水に予め混合してスラリー状にした後、このスラリーを前記焼結用混合原料に添加することにより行う請求項１に記載の焼結鉱の製造方法である。
【００３２】
古紙スラッジを前もって水に混合してスラリー状にしておくことにより、添加物としての古紙スラッジが鉱石等の隙間により均一に入りやすくなるので上記請求項１に記載の発明の作用効果をさらに確実に得られる。
【００３３】
【００３４】
請求項３に記載の発明は、前記焼結用混合原料中のＣａＯ成分の総質量を一定に維持しつつ、前記古紙スラッジの添加質量の増加とともに、製造される焼結鉱の生産率を低下させない範囲で前記焼結用混合原料中の生石灰又は消石灰の質量を減少させることにより行う請求項１又は２に記載の焼結鉱の製造方法である。
【００３５】
請求項３に記載の発明によれば、上記請求項１又は２に記載の発明と同様の作用により生産性を維持ないし向上し、かつ焼結用混合原料中のＣａＯ成分の総質量を一定に維持することにより焼結鉱の塩基度（ＣａＯ／ＳｉＯ２）が一定に保たれるため焼結鉱品質に変動を与えずに、生石灰又は消石灰の使用量を低減できる。
【００３６】
【発明の実施の形態】
本発明の好ましい実施の一形態を以下に示す。
【００３７】
１０ｍｍ以下の鉄鉱石粉（Ｔ．Ｆｅ：５７〜６８質量％、付着水分：約３〜５質量％（外数））６０〜７０質量部（乾量基準）と、焼結返鉱１７〜２１質量部と、副原料として石灰石または生石灰（若しくは消石灰）９〜１１質量部と、必要により珪石少量と、固体燃料としてコークス粉または無煙炭粉３〜５質量部とに、古紙スラッジ（ＣａＯ＋ＭｇＯ：約１０〜３０質量％、ＳｉＯ2＋Ａｌ2Ｏ3：約２０〜３０質量％、繊維分：約４０〜６０質量％、リグニン：約１〜１０質量％）０．０２〜０．０５質量部（乾量基準）を添加し、適量の配合水を追加し合計水分量を６〜８質量部として、ドラムミキサーで混練、疑似粒化した混合原料とする。
【００３８】
なお、古紙スラッジは通常、水分を８０〜１２０質量％（乾量基準）程度含み紙粘土状の塊の状態になっているので、焼結用混合原料へはそのまま添加するより事前に配合水の一部又は全部を添加・攪拌しスラリー状にしたものを用いると均一に分散させやすくなるので好ましい。ただし、スラリー状になりにくいものの場合には、脱水・乾燥後粉砕して粉状で添加するのがよい。乾燥後の古紙スラッジは通常用いられるボールミル等により容易に適当な細かさに粉砕ができるので、この粉砕後の古紙スラッジを用いることにより混合原料中に比較的均一に分散することができるからである。
【００３９】
副原料として添加する石灰石または生石灰（若しくは消石灰）の配合量については、混合原料中におけるＣａＯ成分の総質量を一定（例えば、混合原料１００質量部に対して８質量部）に維持しつつ、古紙スラッジの添加量を多くするにしたがい生石灰（若しくは消石灰）の配合量を減少し、替わりに石灰石の配合量を増加してもよい。すなわち、古紙スラッジの添加量の増大により擬似粒子が強化されるのでバインダーとしての生石灰（若しくは消石灰）の添加量を削減できる。また従来法においては、単に生石灰（若しくは消石灰）を減少して石灰石の配合量を増加すると焼結時に石灰石が分解吸熱（ＣａＣＯ3→ＣａＯ＋ＣＯ2）して熱不足となり焼結鉱強度が低下するため、固体燃料配合量を増加させる必要があったが、本発明によれば、この石灰石の分解吸熱分を古紙スラッジ中の有機繊維と有機粘着材の燃焼発熱分（後述）で補うことができるのでこのような問題は生じない。
【００４０】
このようにして作製した混合原料を、ドワイトロイド式焼結機のパレット上に充填し、表層部の混合原料中のコークス粉または無煙炭粉に着火する。着火後、１５〜２５分間下方に向けて空気を吸引することによりコークス粉または無煙炭粉を燃焼させてこの燃焼熱により充填した混合原料を焼結させて焼結ケーキとする。
【００４１】
この着火から焼結ケーキ製造までの過程で蒸発した水分は充填層下部で凝縮して湿潤層を形成するが、古紙スラッジの添加により擬似粒子が強化されているので擬似粒子の崩壊は起らず通気を阻害しない。すなわち、古紙スラッジ中の繊維の長さは、その約８０質量％以上が１０〜５００μｍ程度であり、この繊維と粘土質物質が有機粘着材であるリグニンで接合され、この接合物が焼結原料の粒子間に配置されて粒子間の摩擦力を高めて滑りにくくすることにより、擬似粒子の崩壊が防止される。これにより、充填層の通気が確保され焼結鉱の生産能率が維持ないし向上する。
【００４２】
また、焼結反応に際し少なくとも９００℃以上（最高１２５０〜１３００℃）の高温の状態が２〜４分間維持される間に、古紙スラッジ中の有機繊維であるセルロース木質繊維と、有機粘着材であるリグニンとは容易に燃焼消失するので焼結反応を阻害することはなく、むしろこれらの燃焼による燃焼熱と、古紙スラッジ中の粘土質物質が鉄鉱石等とスラグ反応して融液を生成することにより焼結反応が促進され、焼結鉱の強度が上昇する。また、これら有機物の燃焼熱が有効利用できるので固体燃料を節減することができる。あるいは、前述したように、生石灰（若しくは消石灰）使用量を削減するため石灰石配合量を増大した場合にも熱不足になることはなく、固体燃料を増加させる必要はない。
【００４３】
古紙スラッジの添加量は、あまり少なすぎては効果が十分得られず、逆に多すぎると粘土質物質の量が増えて高炉のスラグ量が増加することに加え、古紙スラッジ中にはＺｎ、Ｃｌ、Ｎａ、Ｋ等の低融点化合物を生成する成分が含有されている（表１参照）ため高炉内で付着物を形成する等の問題が生じるので、焼結用混合原料１００質量部（乾量基準）に対して、古紙スラッジの添加量は、好ましくは０．０１〜１．０質量部、より好ましくは０．０２〜０．２質量部、さらに好ましくは０．０３〜０．１質量部、特に好ましくは０．０３〜０．０５質量部とする。
【００４４】
古紙スラッジを添加する替わりに、有機繊維、粘土質物質、および有機粘着材をそれぞれ所定量ずつ混合して用いてもよい。これらの添加量は、あまり少なすぎては効果が十分得られず、逆に多すぎると焼結鉱の製造コストが高くなりすぎることに加え、粘土質物質の添加量が多すぎると高炉のスラグ量が増加するので、焼結用混合原料１００質量部（乾量基準）に対して、有機繊維の添加量は、好ましくは０．０１〜１．０質量部、より好ましくは０．０１〜０．２質量部、さらに好ましくは０．０１〜０．０７質量部、特に好ましくは０．０２〜０．０５質量部とし、粘土質物質の添加量は、好ましくは０．０１〜１．０質量部、より好ましくは０．０１〜０．２質量部、さらに好ましくは０．０１〜０．０７質量部、特に好ましくは０．０２〜０．０５質量部とし、有機粘着材の添加量は、好ましくは０．０００５〜０．１質量部、より好ましくは０．００１〜０．０２質量部、さらに好ましくは０．００２〜０．０１質量部、特に好ましくは０．００３〜０．００５質量部とする。
【００４５】
有機繊維としては、例えば、古紙を解砕したセルロース木質繊維を用いてもよいし、布染色工程から発生する織物繊維を含有する布染色スラッジを用いてもよいし、これらを混合して用いてもよい。粘土質物質としては、例えば、粘土、ベントナイト、カオリン、タルク等を単独又は２種以上混合して用いてもよい。有機粘着材としては、リグニンの他に、例えば、澱粉、デキストリン、糖蜜等を単独又は２種以上混合して用いてもよい。あるいは、古紙スラッジにこれらのものを適宜追加して有機繊維、粘土質物質、および有機粘着材の割合を調整して用いてもよい。
【００４６】
【実施例】
本発明の効果を確認するため、焼結鍋試験装置を用いて以下の実験を実施した。
【００４７】
（実施例１）
焼結用混合原料中の生石灰と石灰石の配合量は一定にしたまま、焼結用混合原料に添加剤として、有機繊維、粘土質物質、有機粘着材をそれぞれ単独で添加した場合、これら３種類の添加剤を前もって混合して添加した場合、古紙スラッジを添加した場合について、それぞれ充填層の通気性（ＪＰＵ）、焼結ケーキの落下強度、焼結鉱の生産率を測定した。
【００４８】
有機繊維としては、適当な大きさに裁断した新聞紙に水を添加してミキサーで攪拌しスラリー状にしたものを、粘土質物質としては、粉状のベントナイトを水に溶いたものを、有機粘着材としては、粉状のリグニンを水に溶解し５質量％程度の水溶液としたものを準備し、それぞれ混合原料（乾量基準）に対して０．０３５質量％に相当する添加量とした。なお、これら３種類の添加剤を前もって混合・添加する場合には、質量比で有機繊維５０、粘土質物質４８、有機粘着材２の比率で合計添加量が上記単独添加の場合と同じ、混合原料（乾量基準）に対して０．０３５質量％となる量を配合水に添加し十分に攪拌してスラリー状として用いた。また、古紙スラッジは、表１に示す成分のものに水を添加してミキサーで解砕したスラリー状のものを用い添加量は上記と同じ、混合原料（乾量基準）に対し０．０３５質量％とした。
【００４９】
表２に示す配合比で、１０ｍｍ以下の鉄鉱石粉、焼結返鉱、３ｍｍ以下の副原料（石灰石、生石灰、珪石）およびコークス粉に、上記添加剤を含有するスラリーまたは溶液を添加し、さらに混合原料水分が７質量％（混合原料（乾量基準）の外数）となるよう水を追加し、ドラムミキサーにより疑似粒子化して混合原料を製造した。
【００５０】
なお、本実施例１で使用した配合鉄鉱石粉の成分を表３に示す。
【００５１】
【表１】
【表２】
【表３】
このようにして製造した混合原料を直径１００ｍｍ、高さ３００ｍｍの焼結鍋に充填し、冷間で一定吸引圧で大気を吸引しそのときの吸引ガス流量を測定することによって、以下の式（１）で定義される通気性指数ＪＰＵを求めた。
【００５５】
ＪＰＵ＝（Ｆ／Ａ）・〔ｈ／（ｓ／９．８０６６５）〕0.6 …（１）
ここに、Ｆ：吸引ガス流量（ｍ3（標準状態）／ｍｉｎ）、Ａ：充填層断面積（ｍ2）、ｈ：充填層高さ（ｍ）、ｓ：吸引圧力（ｋＰａ）
その後、充填層の層頂面に着火し、吸引圧力３．５３ｋＰａで空気を吸引しながら焼結を行った。焼結後、焼結ケーキの落下強度を測定した。なお、落下強度は、焼結ケーキを２ｍの高さから鉄製台上に一度に落下させる操作を４回繰り返した後、全量を５ｍｍの篩で篩い分けし、５ｍｍ以上の割合を求めたものである。また、生産率は、単位断面積、単位時間当たりの製品焼結鉱（落下強度試験後の５ｍｍ以上）の製造量であり、焼結ケーキの全重量に落下強度（歩留り）を掛け、焼結鍋の断面積と焼成時間で割って求めたものである。なお、焼成時間は、着火から火落ち（排ガス温度が一旦５００〜６００℃まで上昇した後、低下して２００℃に達した時）までの時間である。実験結果を表４に示す。
【００５６】
【表４】
表４より明らかなように、従来の添加剤なしのケース（実験Ｎｏ．１）に比較し、繊維、ベントナイト、リグニンをそれぞれ単独で添加した場合（実験Ｎｏ．２〜４）、通気性（ＪＰＵ）、落下強度、生産率とも改善される傾向にはあるが、その効果は小さい。それに対して、繊維、ベントナイト、およびリグニンを同時に添加した場合（実験Ｎｏ．５）には、その合計添加量は単独で添加した場合（実験Ｎｏ．２〜４）と同じであるのも係わらず、通気性（ＪＰＵ）、落下強度、生産率とも大きく改善されるのが確認された。また、古紙スラッジを用いた場合（実験Ｎｏ．６）にも、繊維、ベントナイト、およびリグニンを同時に添加した場合（実験Ｎｏ．５）と同様の改善効果が確認された。
【００５８】
（実施例２）
次に、焼結用混合原料中のＣａＯ成分の総質量を一定に維持しつつ、焼結用混合原料に添加剤として古紙スラッジを添加し、生石灰と石灰石の配合量を種々変化させた場合について、それぞれ充填層の通気性（ＪＰＵ）、焼結ケーキの落下強度、焼結鉱の生産率を測定した。
【００５９】
なお、古紙スラッジは、実施例１と同じく、表１に示す成分のものに水を添加してミキサーで解砕してスラリー状に処理したものを、混合原料（乾量基準）に対し０．０３５質量％添加した。
【００６０】
表５の実験Ｎｏ．１４〜１６に示す配合比で、実施例１と同様、１０ｍｍ以下の鉄鉱石粉、焼結返鉱、３ｍｍ以下の副原料（石灰石、生石灰、珪石）およびコークス粉に、上記古紙スラッジを含有するスラリーを添加し、さらに混合原料水分が７質量％（混合原料（乾量基準）の外数）となるよう水を追加し、ドラムミキサーにより疑似粒子化して混合原料を製造した。また比較のため、表５の実験Ｎｏ．１１〜１３に示す配合比で、前記スラリーを添加しない場合についても混合原料を製造した。本実施例２で使用した配合鉄鉱石粉の成分は、実施例１と同じ表３に示すものである。なお、表５の実験Ｎｏ．１１及び１４の混合原料は、それぞれ表４の実験Ｎｏ．１及び６と同じ混合原料である。
【００６１】
このようにして製造した混合原料について、実施例１と同じ焼結鍋を用い同じ実験条件でＪＰＵ、落下強度、生産率を測定した。実験結果を表５に併せて示す。なお、表５の実験Ｎｏ．１１及び１４は、それぞれ表４の実験Ｎｏ．１及び６の実験結果をそのまま援用したものである。
【００６２】
表５の実験結果から、実験Ｎｏ．１１→１４→１５→１６へと順次、古紙スラッジ添加量又は生石灰使用量を変更したときのＪＰＵ、落下強度、及び生産率の変化は以下の通りである。すなわち,実験Ｎｏ．１１では、古紙スラッジを添加せずに生石灰を新原料１００質量部に対して２．０質量部配合して、ＪＰＵが４０．０、落下強度が６７．５質量％、生産率が１．１０ｔ／（ｍ2ｈ）であったのに対して、実験Ｎｏ．１４では、実験Ｎｏ．１１の混合原料にさらに古紙スラッジを混合原料１００質量部に対して０．０３５質量部添加したことにより、ＪＰＵが４５．２、落下強度が７２．９質量％、生産率が１．２３ｔ／（ｍ2ｈ）へといずれの指標値とも大幅に上昇した。次に、実験Ｎｏ．１５で、実験Ｎｏ．１１の混合原料から生石灰の配合量を新原料１００質量部に対して１．０質量部減少させて１．０質量部としたことにより、ＪＰＵが４２．７、落下強度が７２．５質量％、生産率が１．１７ｔ／（ｍ2ｈ）となり、各指標値は、実験Ｎｏ．１４よりは低くなったものの、実験Ｎｏ．１１に比べると依然として高い値を示した。そして実験Ｎｏ．１６で、さらに生石灰の配合量を新原料１００質量部に対して１．０質量部減少させて生石灰配合量を０としたことにより、ＪＰＵが３９．９、落下強度が６７．８質量％、生産率が１．０７ｔ／（ｍ2ｈ）となり、各指標値が漸く実験Ｎｏ．１１と同等かやや低い値となった。
【００６３】
以上の結果から、実験Ｎｏ．１１の混合原料にさらに古紙スラッジを混合原料１００質量部に対して０．０３５質量部添加することにより、生石灰を新原料１００質量部に対して少なくとも１．０質量部減少させても焼結鉱強度を低下させることなく、かつ焼結鉱製造の生産性を維持しつつ、生石灰の使用量を減少できることが明らかである。
【００６４】
また、実験Ｎｏ．１２→１５→１６へと順次、古紙スラッジ添加量又は生石灰使用量を変更したときのＪＰＵ、落下強度、及び生産率の変化についても同様の傾向が見られる。
【００６５】
以上の結果より、古紙スラッジを適量添加することにより、焼結鉱強度を低下させることなく、かつ焼結鉱製造の生産性を維持しつつ、生石灰の使用量を減少できることが確認できた。
【００６６】
なお、古紙スラッジの替わりに、有機繊維、粘土質物質、及び有機粘着材の混合物を用いても同様の効果が得られることは実施例１の実験結果から明らかである。
【００６７】
【表５】
【発明の効果】
請求項１に記載の発明によれば、添加物として古紙スラッジを用いることにより、焼結用混合原料に有機繊維と、粘土質物質と、有機粘着材とを同時に添加混合することにより擬似粒子の強度を高めてその崩壊を防止し、その結果、焼結ベッドの通気性が改善され、焼結鉱製造の生産性が向上する。
さらに、従来廃棄物とされていたものを資源およびエネルギーとして有効利用でき、かつ環境汚染の防止にも寄与する。
【００６９】
【００７０】
【００７１】
【００７２】
請求項２に記載の発明によれば、古紙スラッジを前もって水に混合してスラリー状にしておくことにより、添加物として古紙スラッジが鉱石等の隙間により均一に入りやすくなるので上記請求項１に記載の発明の作用効果をさらに確実に得られる。
【００７３】
請求項３に記載の発明によれば、混合原料に古紙スラッジを適量添加することにより、焼結鉱強度を低下させることなく、かつ焼結鉱製造の生産性を維持しつつ、生石灰又は消石灰の使用量を減少できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing sintered ore, and particularly to an additive for a mixed raw material for sintering that can achieve high productivity without deteriorating the quality of the sintered ore.
[0002]
[Prior art]
Usually, the sintered ore which is a raw material for blast furnaces is manufactured in the following processes.
[0003]
First, iron ore powder with a particle size of about 10 mm or less, sintered reversion with the same particle size, auxiliary materials such as silica, limestone, and serpentine with a particle size of about 3 mm or less, and solid fuels such as coke powder and coal powder And flocculant such as quick lime and slaked lime are mixed, mixed water is added, and kneading is followed by quasi-particle formation (formed by attaching fine particles to the surface by the surface tension of water with coarse particles as the core) The mixed raw material thus prepared is filled on a pallet of a sintering machine (for example, a dwroid type sintering machine), and the solid fuel in the mixed raw material at the top of the layer is ignited. After ignition, in the process of burning the solid fuel while sucking air downward and sintering the mixed raw material filled with this combustion heat to form a sintered cake, the mixed raw material is dried, then to 1150-1200 ° C. By heating, a melt is generated by a slag reaction between the iron ore in the mixed raw material and the auxiliary raw material. Liquid melt sintering of the iron ore powder is performed with this melt, and after cooling, the required strength of the sintered ore is obtained by combining the iron ore powder with this melt.
[0004]
Due to the recent trend toward finer iron ore powder due to changes in iron ore resources and the increase in the ratio of limonite ore, the granulation property of the sintered raw material deteriorates and the strength of pseudo particles decreases, making it easy to collapse (especially In the moisture condensation zone (wet zone) at the lower part of the packed bed during sintering, the load from the upper part is large and the pseudo particles tend to collapse), and the air permeability of the mixed raw material deteriorates and the time required for sintering becomes longer. The production efficiency of sintered ore tends to decrease. In order to maintain or increase the production efficiency, a method is known in which the amount of flocculant such as quick lime and slaked lime is increased to strengthen the pseudo-particles. There is a problem that the manufacturing cost of the ore becomes high.
[0005]
Various methods have been proposed as a method for maintaining or increasing the production efficiency at low cost without increasing the amount of quicklime, slaked lime and the like.
[0006]
For example, a method for improving the ventilation of the packed bed by adding a rice bran as a voided material to the sintering raw material (Japanese Patent Laid-Open No. 57-140835), and adding a polystyrene foam as a loose filler to improve the ventilation of the packed bed. Although a method (Japanese Patent Laid-Open No. 59-166632) has been proposed, it has not been put into practical use yet because it is difficult to ensure the amount of rice bran and polystyrene foam.
[0007]
Moreover, by mixing 0.01-3 kg / sintered raw material t of used paper into the sintered raw material, the packed layer is loosely packed and the raw water is absorbed by the used paper to sinter the lower layer moisture condensation zone (wet) The proposal has been made to reduce the water content of the belt and improve the air permeability (Japanese Patent Laid-Open No. 7-18344). However, a separate facility is needed to cut the waste paper to an appropriate size to be added to the sintering material. Therefore, in addition to the fact that the cost reduction effect cannot be expected, the moisture absorbed in the waste paper will eventually evaporate and reach the lower layer, so it is unlikely that the moisture in the wet zone will decrease, and the effect of improving air permeability will not be obtained Probability is high.
[0008]
Also, by adding 3% by weight or less of linear or scaly iron source to the sintered ore blending raw material, and improving the air permeability by maintaining the space between the pseudo particles and the reinforcement of the pseudo particles properly. Although a proposal to be made (JP-A-57-73135) has been made, steel fibers, old nails, wire rods, spiral cutting scraps, etc. are required as a linear or scaly iron source, and the amount is secured. It is difficult to put it to practical use.
[0009]
Furthermore, when using limonite-like iron ore as a sintering raw material, one or two or more kinds of coarse limonite are selected from the SiO 2 clayey material containing a small amount of Al 2 O 3 and the MgO—SiO 2 -containing ore. Proposal to prevent airflow failure due to the rapid melting reaction of limonite ore during sintering by covering the surface of coarse-grained limonite ore with these substances by adding 5 to 15% by weight to the ore and mixing and grinding. Japanese Patent Publication No. 58-55221), but in addition to the problem that the equipment cost rises because an extra step of preliminarily screening limonite ore into fine powder and coarse particles is necessary, it is wet Since the effect of preventing the collapse of the pseudo particles in the belt is small, the effect of improving the air permeability is limited and has not been put into practical use.
[0010]
On the other hand, various proposals have also been made for methods for reducing the production cost of sintered ore by reducing the amount of quicklime (or slaked lime) used while maintaining the production efficiency.
[0011]
For example, the mixing tank has a double structure consisting of an outer wall and an inner wall, leads high-temperature sintering cooler exhaust gas into the gap between the outer wall and the inner wall, and preheats the sintering raw material in the mixing tank There has been a proposal (Japanese Patent Laid-Open No. 3-31429) for reducing the unit consumption of quick lime by improving the activity of quick lime. However, this method has a problem of requiring a large amount of remodeling cost because it requires remodeling of the compounding tank with a double structure and a new pipe for introducing high-temperature gas from the sintering cooler to the compounding tank.
[0012]
In addition, a proposal (Japanese Patent Laid-Open No. 3-134123) has been made to reduce the amount of quicklime used by granulating a sintering raw material together with a resin solution such as melamine, acrylic, and vinyl acetate and water. However, since this method uses an expensive resin, the cost reduction effect by reducing the amount of quicklime is small, and the influence on the quality of sintered ore is unknown. Further, when a resin containing nitrogen such as a melamine resin is used, there is a concern about the influence on the surrounding environment such as generation of nitrogen oxides by combustion during the sintering reaction.
[0013]
In addition, by adding fine steel scraps such as quick lime and steel dairy powder to the sintered raw material and granulating, the increase in the particle size of the granulated product is compared with the case of granulating with a simple mix of quick lime. As a result of this, a proposal has been made to reduce the amount of quicklime using the increase in the drop strength of the granulated product. However, in this method, in addition to difficult to ensure the amount of steel scrap such as steel darai powder, impurity elements such as Zn and Pb in the steel scrap are contained in the sintered ore and brought into the blast furnace, It may adversely affect blast furnace operation and is difficult to apply in practice.
[0014]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide means for improving productivity at low cost by improving the air permeability of the sintered layer without increasing the amount of expensive quicklime and the like and without requiring extra equipment. There is.
[0015]
Another object of the present invention is to provide means for reducing cost by reducing expensive quicklime while maintaining productivity.
[0016]
[Means for Solving the Problems]
In order to improve the air permeability of the sintered layer, the present inventors consider that it is important to increase the strength of the pseudo particles in order to prevent the pseudo particles from collapsing in the condensed layer. Attention was paid to various types of additives, combinations, and amounts added. As a result, it has been found that the above-mentioned problems can be solved by combining organic fibers, clayey substances, and organic adhesive materials as additives and simultaneously adding them to the sintered mixed raw material.
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
The invention according to claim 1 is a waste paper sludge of 0.01 to 1.1.0 based on 100 parts by mass (dry basis) of a mixed raw material for sintering composed of iron ore powder, sintered return mineral, auxiliary raw material, and solid fuel. It is a method for producing a sintered ore characterized in that 0 part by mass (dry basis) is added and mixed and sintered by a conventional method.
[0030]
Waste paper sludge is obtained by separating and recovering the suspended matter contained in the waste liquid after removing pulp from the waste paper suspension slurry obtained by adding a solution containing an alkali agent or the like in the waste paper recycling process to break up the waste paper. Therefore, the waste paper sludge contains a considerable amount of cellulose wood fiber, which is a relatively short organic fiber, and is concentrated with inorganic fillers and inorganic pigments of waste paper such as bentonite, talc, limestone, dolomite and the like, because it contains lignin is more organic adhesive, by using this, it is possible to obtain the following effects.
That is, when organic fiber, clay material, and organic adhesive material are added to the sintered mixed raw material at the same time, organic fiber and clay material are poorly water-soluble, but organic adhesive material is easily water-soluble, so it is sintered and mixed. It dissolves in the raw water and enters the contact point between the organic fibers and the clay material to join them together. Since this joined material enters between particles such as ore and limestone as a sintered mixed raw material and increases friction between the particles, the pseudo particles are prevented from collapsing even in the wet zone. As a result, the air permeability of the packed bed is remarkably improved, and the productivity of sinter ore production is dramatically improved. Organic fibers and organic adhesives are burned during sintering and used as fuel, so the amount of solid fuel such as coke and coal can be reduced, and clayey substances react with iron ore and slag to react with the melt. To promote the sintering reaction.
In addition, most of the waste paper sludge has been dehydrated or dried and landfilled or incinerated, and it has been expensive to dispose of it as an additive for sintered ore produced in large quantities. By using it, it not only can be effectively used as a resource and energy, but also contributes to prevention of environmental pollution. In the case of the method using the used paper itself described in the description of the prior art (Japanese Patent Laid-Open No. 7-18344), in addition to the used paper sludge, the used paper is composed of relatively long fibers and sintered. The effect of the present invention cannot be achieved because the fibers are not disaggregated when added to the raw material and the amount of clayey material is very small compared to the amount of fibers.
And, if the added amount of waste paper sludge is too small, the above effect cannot be obtained sufficiently. On the other hand, if the added amount is too large, the amount of clayey material added becomes too large and the amount of slag in the blast furnace increases. It is preferable to make it the addition amount of.
[0031]
The invention according to claim 2 is carried out by previously mixing the waste paper sludge with the compounded water added to the mixed raw material to form a slurry, and then adding this slurry to the mixed raw material for sintering. 1. A method for producing a sintered ore according to 1 .
[0032]
By mixing the waste paper sludge with water in advance to form a slurry , it becomes easier for the waste paper sludge as an additive to easily enter into the gaps of ore or the like, so that the operational effect of the invention of claim 1 can be further ensured. Is obtained .
[0033]
[0034]
The invention according to claim 3 decreases the production rate of the sintered ore to be produced as the added mass of the waste paper sludge increases while maintaining the total mass of the CaO component in the mixed raw material for sintering constant. It is a manufacturing method of the sintered ore of Claim 1 or 2 performed by reducing the mass of the quicklime or slaked lime in the said mixing raw material for sintering in the range which is not made to do.
[0035]
According to the invention described in claim 3 , the productivity is maintained or improved by the same action as that of the invention described in claim 1 or 2 , and the total mass of the CaO component in the mixed raw material for sintering is kept constant. By maintaining it, the basicity (CaO / SiO 2 ) of the sintered ore is kept constant, so that the amount of quicklime or slaked lime used can be reduced without changing the quality of the sintered ore.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
One preferred embodiment of the present invention is shown below.
[0037]
Iron ore powder of 10 mm or less (T.Fe: 57 to 68% by mass, adhesion moisture: about 3 to 5% by mass (outside number)) 60 to 70 parts by mass (dry basis) and sintered ore 17 to 21 mass Parts, 9 to 11 parts by mass of limestone or quicklime (or slaked lime) as an auxiliary material, a small amount of silica if necessary, and 3 to 5 parts by mass of coke powder or anthracite coal powder as a solid fuel, waste paper sludge (CaO + MgO: about 10 to 10 parts) 30% by mass, SiO 2 + Al 2 O 3 : about 20-30% by mass, fiber content: about 40-60% by mass, lignin: about 1-10% by mass) 0.02-0.05 parts by mass (dry basis) ), An appropriate amount of blended water is added, and the total water content is 6 to 8 parts by mass to obtain a mixed raw material kneaded and pseudo-granulated with a drum mixer.
[0038]
Waste paper sludge usually contains about 80 to 120% by weight (dry basis) of water and is in the form of a paper clay lump. It is preferable to add a part or all of the mixture and stir it into a slurry to facilitate uniform dispersion. However, if it is difficult to form a slurry, it is preferable to add it in powder form after dehydration and drying. This is because the waste paper sludge after drying can be easily pulverized to a suitable fineness by a commonly used ball mill or the like, and can be dispersed relatively uniformly in the mixed raw material by using this waste paper sludge after pulverization. .
[0039]
Regarding the blending amount of limestone or quicklime (or slaked lime) added as an auxiliary raw material, the total weight of the CaO component in the mixed raw material is kept constant (for example, 8 parts by weight with respect to 100 parts by weight of the mixed raw material), and used paper As the amount of sludge added is increased, the amount of quicklime (or slaked lime) may be decreased, and the amount of limestone may be increased instead. That is, since the pseudo particles are reinforced by increasing the amount of waste paper sludge added, the amount of quick lime (or slaked lime) added as a binder can be reduced. Further, in the conventional method, when the amount of limestone is increased simply by reducing quick lime (or slaked lime), the limestone decomposes and absorbs heat (CaCO 3 → CaO + CO 2 ) at the time of sintering, resulting in insufficient heat and lowering the strength of the sintered ore. However, according to the present invention, the decomposition endothermic component of limestone can be supplemented with the combustion exothermic component (described later) of organic fibers and organic adhesive in waste paper sludge. Such a problem does not occur.
[0040]
The mixed raw material thus produced is filled on a pallet of a dweroid-type sintering machine, and the coke powder or the anthracite coal powder in the mixed raw material in the surface layer portion is ignited. After ignition, air is sucked downward for 15 to 25 minutes to burn coke powder or anthracite coal powder, and the mixed raw material filled with this combustion heat is sintered to form a sintered cake.
[0041]
Moisture evaporated in the process from ignition to sintering cake formation condenses in the lower part of the packed bed to form a wet layer, but the pseudo particles are strengthened by the addition of waste paper sludge, so the pseudo particles do not collapse. Does not impede ventilation. That is, the length of the fiber in the waste paper sludge is about 80% by mass or more of about 10 to 500 μm, and this fiber and the clay material are joined with lignin which is an organic adhesive material. By disposing the particles between the particles and increasing the frictional force between the particles to make it difficult to slip, the pseudo particles are prevented from collapsing. Thereby, ventilation of the packed bed is ensured, and the production efficiency of the sintered ore is maintained or improved.
[0042]
Further, during the sintering reaction, while the high temperature state of at least 900 ° C. or higher (maximum 1250 to 1300 ° C.) is maintained for 2 to 4 minutes, it is a cellulose wood fiber that is an organic fiber in waste paper sludge and an organic adhesive material. Lignin easily burns away and does not hinder the sintering reaction. Rather, the combustion heat from the combustion and the clay material in waste paper sludge react with iron ore to produce a melt. This promotes the sintering reaction and increases the strength of the sintered ore. Moreover, since the combustion heat of these organic substances can be used effectively, solid fuel can be saved. Alternatively, as described above, when the amount of limestone is increased in order to reduce the amount of quicklime (or slaked lime) used, heat does not become insufficient, and there is no need to increase the solid fuel.
[0043]
If the amount of waste paper sludge added is too small, the effect will not be sufficiently obtained.On the other hand, if the amount is too large, the amount of clayey substance will increase and the amount of slag in the blast furnace will increase. Since components that generate low melting point compounds such as Cl, Na, K and the like are contained (see Table 1), problems such as formation of deposits in the blast furnace arise, so that 100 parts by mass of the mixed raw material for sintering (dry matter) The amount of waste paper sludge added is preferably 0.01 to 1.0 part by mass, more preferably 0.02 to 0.2 part by mass, and still more preferably 0.03 to 0.1 part by mass. Parts, particularly preferably 0.03 to 0.05 parts by mass.
[0044]
Instead of adding waste paper sludge, organic fibers, clayey substances, and organic adhesive materials may be mixed and used in predetermined amounts. If the addition amount is too small, the effect is not sufficiently obtained. On the other hand, if the addition amount is too large, the production cost of the sinter becomes too high. Since the amount increases, the addition amount of the organic fiber is preferably 0.01 to 1.0 part by mass, more preferably 0.01 to 0 with respect to 100 parts by mass (dry basis) of the mixed raw material for sintering. .2 parts by mass, more preferably 0.01 to 0.07 parts by mass, particularly preferably 0.02 to 0.05 parts by mass, and the addition amount of the clayey substance is preferably 0.01 to 1.0 parts by mass. Parts, more preferably 0.01 to 0.2 parts by weight, still more preferably 0.01 to 0.07 parts by weight, particularly preferably 0.02 to 0.05 parts by weight. Preferably it is 0.0005-0.1 mass part, More preferably, it is 0.001. 0.02 parts by weight, more preferably 0.002 parts by mass, particularly preferably at 0.003-0.005 parts by weight.
[0045]
As the organic fibers, for example, cellulose wood fibers obtained by pulverizing waste paper may be used, cloth dye sludge containing fabric fibers generated from the cloth dyeing process may be used, or these may be mixed and used. Also good. As the clay material, for example, clay, bentonite, kaolin, talc and the like may be used alone or in combination of two or more. As the organic adhesive material, in addition to lignin, for example, starch, dextrin, molasses and the like may be used alone or in admixture of two or more. Alternatively, these may be appropriately added to the used paper sludge to adjust the proportions of organic fiber, clayey substance, and organic adhesive material.
[0046]
【Example】
In order to confirm the effect of the present invention, the following experiment was conducted using a sintering pot test apparatus.
[0047]
Example 1
When adding organic fiber, clayey material, and organic adhesive material alone as additives to the mixed raw material for sintering while keeping the mixing amount of quick lime and limestone in the mixed raw material for sintering, these three types When the additive was added in advance and the waste paper sludge was added, the air permeability (JPU) of the packed bed, the drop strength of the sintered cake, and the production rate of the sintered ore were measured.
[0048]
The organic fiber is made by adding water to a newspaper cut into an appropriate size and stirring with a mixer to form a slurry. The clay material is made by dissolving powdered bentonite in water. As the material, powdered lignin was dissolved in water to prepare an aqueous solution of about 5% by mass, and the amount added was equivalent to 0.035% by mass with respect to the mixed raw material (dry basis). In addition, when mixing and adding these three types of additives in advance, the total addition amount is the same as in the case of the above single addition in the mass ratio of the organic fiber 50, the clay material 48, and the organic adhesive material 2. An amount of 0.035% by mass with respect to the raw material (dry basis) was added to the blended water and stirred sufficiently to be used as a slurry. In addition, the waste paper sludge is the same as the components shown in Table 1 and pulverized with a mixer, and the addition amount is the same as above, and the addition amount is 0.035 mass relative to the mixed raw material (dry basis). %.
[0049]
A slurry or solution containing the above additives is added to iron ore powder of 10 mm or less, sintered ore, 3 mm or less of auxiliary materials (limestone, quicklime, silica) and coke powder, with the mixing ratio shown in Table 2, and Water was added so that the water content of the mixed raw material was 7% by mass (outside number of the mixed raw material (dry basis)), and the mixed raw material was produced by quasi-particle formation using a drum mixer.
[0050]
In addition, Table 3 shows the components of the blended iron ore powder used in Example 1.
[0051]
[Table 1]
[Table 2]
[Table 3]
The mixed raw material thus produced is filled into a sintering pan having a diameter of 100 mm and a height of 300 mm, the air is sucked in at a constant suction pressure in the cold, and the suction gas flow rate at that time is measured. The air permeability index JPU defined in 1) was determined.
[0055]
JPU = (F / A) · [h / (s / 9.80665)] 0.6 (1)
Here, F: suction gas flow rate (m 3 (standard state) / min), A: packed bed cross-sectional area (m 2 ), h: packed bed height (m), s: suction pressure (kPa)
Thereafter, the top surface of the packed layer was ignited and sintered while sucking air at a suction pressure of 3.53 kPa. After sintering, the drop strength of the sintered cake was measured. The drop strength was obtained by repeating the operation of dropping the sintered cake onto the iron table from a height of 2 m at a time four times and then sieving the whole amount with a 5 mm sieve to obtain a ratio of 5 mm or more. is there. The production rate is the production volume of product sintered ore (unit: 5 mm or more after the drop strength test) per unit cross-sectional area and unit time. The total weight of the sintered cake is multiplied by the drop strength (yield) and sintered. It is obtained by dividing by the cross-sectional area of the pan and the firing time. Note that the firing time is the time from ignition to fire dropping (when the exhaust gas temperature once rises to 500 to 600 ° C. and then falls to 200 ° C.). The experimental results are shown in Table 4.
[0056]
[Table 4]
As is clear from Table 4, compared to the case without the additive (Experiment No. 1), when fiber, bentonite, and lignin were added alone (Experiment No. 2 to 4), air permeability (JPU ), Drop strength and production rate tend to be improved, but the effect is small. On the other hand, when fiber, bentonite, and lignin are added simultaneously (Experiment No. 5), the total addition amount is the same as when adding alone (Experiment No. 2 to 4). It was confirmed that air permeability (JPU), drop strength, and production rate were greatly improved. In addition, when waste paper sludge was used (Experiment No. 6), the same improvement effect was confirmed as when fiber, bentonite, and lignin were added simultaneously (Experiment No. 5).
[0058]
(Example 2)
Next, about the case where waste paper sludge is added as an additive to the mixed raw material for sintering while the total amount of CaO components in the mixed raw material for sintering is kept constant, and the blending amount of quicklime and limestone is variously changed. The permeability of the packed bed (JPU), the drop strength of the sintered cake, and the production rate of the sintered ore were measured.
[0059]
As in Example 1, the waste paper sludge was prepared by adding water to the components shown in Table 1, pulverizing with a mixer, and treating the slurry into a slurry state, with respect to the mixed raw material (dry basis). 035 mass% was added.
[0060]
Experiment No. of Table 5 A slurry containing the above-mentioned waste paper sludge in an iron ore powder of 10 mm or less, sintered ore, 3 mm or less of auxiliary materials (limestone, quicklime, silica) and coke powder at the mixing ratios shown in 14 to 16 Further, water was added so that the mixed raw material moisture became 7% by mass (outside number of the mixed raw material (dry basis)), and the mixed raw material was manufactured by quasi-particle formation with a drum mixer. For comparison, the experiment No. The mixed raw material was manufactured also in the case where the said slurry was not added with the compounding ratio shown to 11-13. The components of the blended iron ore powder used in Example 2 are those shown in Table 3 as in Example 1. In addition, the experiment No. The mixed raw materials of Nos. 11 and 14 are the experiment Nos. It is the same mixed raw material as 1 and 6.
[0061]
About the mixed raw material manufactured in this way, JPU, drop strength, and production rate were measured under the same experimental conditions using the same sintering pot as in Example 1. The experimental results are also shown in Table 5. In addition, the experiment No. 11 and 14 are the experiment Nos. In Table 4, respectively. The experimental results of 1 and 6 are used as they are.
[0062]
From the experimental results in Table 5, the experiment No. Changes in JPU, drop strength, and production rate when the waste paper sludge addition amount or quick lime usage amount is changed sequentially from 11 → 14 → 15 → 16 are as follows. That is, Experiment No. In No. 11, quick lime is mixed in an amount of 2.0 parts by mass with respect to 100 parts by mass of the new raw material without adding waste paper sludge, the JPU is 40.0, the drop strength is 67.5% by mass, and the production rate is 1.10 t. / (M 2 h), while experiment No. No. 14, Experiment No. Furthermore, by adding 0.035 parts by weight of waste paper sludge to 100 parts by weight of the mixed raw material to 11 mixed raw materials, the JPU is 45.2, the drop strength is 72.9% by weight, and the production rate is 1.23 t / ( Both index values rose significantly to m 2 h). Next, Experiment No. 15 and experiment no. By reducing the blending amount of quick lime from 11 mixed raw materials by 1.0 part by mass with respect to 100 parts by mass of the new raw material to 1.0 part by mass, JPU was 42.7 and the drop strength was 72.5% by mass. The production rate is 1.17 t / (m 2 h). Although it was lower than 14, the experiment No. Compared to 11, the value was still high. And experiment no. 16, by further reducing the compounding amount of quick lime by 1.0 part by mass with respect to 100 parts by mass of the new raw material and setting the compounding amount of quick lime to 0, JPU was 39.9, drop strength was 67.8% by mass, The production rate was 1.07 t / (m 2 h), and each index value gradually increased in Experiment No. 11 or slightly lower value.
[0063]
From the above results, Experiment No. In addition, by adding 0.035 parts by weight of waste paper sludge to 100 parts by weight of the mixed raw material to 11 mixed raw materials, the sintered ore is reduced even if the quick lime is reduced by at least 1.0 parts by weight with respect to 100 parts by weight of the new raw material. It is clear that the amount of quicklime used can be reduced without reducing the strength and maintaining the productivity of the sinter production.
[0064]
In addition, Experiment No. The same tendency is observed for changes in JPU, drop strength, and production rate when the amount of used paper sludge added or the amount of quicklime is changed sequentially from 12 to 15 to 16.
[0065]
From the above results, it was confirmed that by using an appropriate amount of waste paper sludge, the amount of quicklime used can be reduced without reducing the strength of the sintered ore and maintaining the productivity of the sintered ore production.
[0066]
In addition, it is clear from the experimental results of Example 1 that the same effect can be obtained by using a mixture of organic fiber, clayey substance, and organic adhesive instead of waste paper sludge.
[0067]
[Table 5]
【The invention's effect】
According to the first aspect of the present invention, by using waste paper sludge as an additive , the organic fiber, the clay material, and the organic adhesive material are simultaneously added to and mixed with the raw material for sintering, so that the pseudo particles The strength is increased to prevent its collapse, and as a result, the air permeability of the sintered bed is improved and the productivity of sinter ore production is improved.
Furthermore, what was conventionally considered as waste can be effectively used as resources and energy, and contributes to prevention of environmental pollution.
[0069]
[0070]
[0071]
[0072]
According to the invention described in claim 2, by which mixed beforehand water waste paper sludge keep the slurry, additives because waste paper sludge is likely to enter uniformly by gaps, such as ore to the claim 1 as The effects of the described invention can be obtained more reliably .
[0073]
According to the invention described in claim 3, by adding an appropriate amount of wastepaper sludge in the mixed material, without reducing the sintered ore strength, and while maintaining the productivity of sintered ore production, quick lime or hydrated lime Can be reduced.
Claims (3)
Priority Applications (1)
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| JP2001108594A JP3825272B2 (en) | 2001-01-17 | 2001-04-06 | Method for producing sintered ore |
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| JP2001-8939 | 2001-01-17 | ||
| JP2001008939 | 2001-01-17 | ||
| JP2001108594A JP3825272B2 (en) | 2001-01-17 | 2001-04-06 | Method for producing sintered ore |
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| KR20010058306A (en) * | 1999-12-27 | 2001-07-05 | 이구택 | Method for manufacturing sinter |
| KR100469299B1 (en) * | 2000-12-16 | 2005-01-31 | 주식회사 포스코 | sinter manufacture method |
| KR20030054033A (en) * | 2001-12-24 | 2003-07-02 | 주식회사 포스코 | Method for manufacturing the blending material for the sintering process |
| JP2008144256A (en) * | 2006-12-13 | 2008-06-26 | China Steel Corp | Method for producing sintered ore and ore composition for producing sintered ore |
| DE102009023928A1 (en) * | 2009-06-04 | 2010-12-09 | Rheinkalk Gmbh | Process for producing an agglomerate |
| JP5475630B2 (en) * | 2010-12-15 | 2014-04-16 | 株式会社神戸製鋼所 | Agglomerate for producing reduced iron and method for producing the same |
| JP2013181187A (en) * | 2012-02-29 | 2013-09-12 | Nisshin Steel Co Ltd | Method for granulating sintering material |
| JP6848898B2 (en) * | 2018-02-19 | 2021-03-24 | Ｊｆｅスチール株式会社 | Manufacturing method of molded sinter raw material and manufacturing method of sinter |
| JP7371610B2 (en) * | 2019-11-29 | 2023-10-31 | Ｊｆｅスチール株式会社 | Method for producing shaped sintered raw material and method for producing sintered ore |
| CN111809042A (en) * | 2020-06-09 | 2020-10-23 | 包头钢铁（集团）有限责任公司 | Use super high SiO2Method for preparing sintered ore from limonite with content |
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