JP3741595B2 - Unshaped refractory raw material and unshaped refractory - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、スラグに対する優れた耐食性を有するアルミナ−酸化ニッケル系及び炭化珪素−アルミナ−酸化ニッケル系の不定形耐火物原料及び該耐火物原料から製造された不定形耐火物に関するものである。
【０００２】
【従来の技術】
従来より、不定形耐火物として、アルミナセメントを無機結合材として用いた、アルミナ骨材を主成分とするアルミナ系不定形耐火物及び炭化珪素骨材を主成分とする炭化珪素系不定形耐火物が知られている。アルミナ系不定形耐火物及び炭化珪素系不定形耐火物は共に耐熱性に優れるが、特に、炭化珪素系不定形耐火物は、塩基性の溶融スラグに対する浸透性が低く耐食性に優れる。これら耐火物は、溶鉱取鍋用耐火物として広く用いられている。
【０００３】
近年、上記不定形耐火物は、溶融炉用耐火物としての使用が考えられるようになってきている。しかし、溶融炉用耐火物は塩基性の溶融スラグと直接に接触するため、溶鉱取鍋用耐火物に比べて耐食性の要求が厳しい。このため、従来の不定形耐火物は、比較的耐食性に優れる炭化珪素系不定形耐火物であっても、溶融炉用耐火物としては耐食性が十分でなかった。
【０００４】
このような問題を解決するものとして、特開平９−２７８５４０号公報には、カーボンと酸化コバルトを添加して焼成した炭化珪素系不定形耐火物が開示されており、この耐火物によれば耐食性をより向上させることができる。しかしながら、上記耐火物で用いられる酸化コバルトは高価であるため、製造される不定形耐火物も高価になるという問題があった。
【０００５】
【発明が解決しようとする課題】
酸化コバルトを用いずに耐食性を向上させる方法としては、例えば、アルミナ系不定形耐火物で既に用いられ耐火物に高い耐食性を付与するマグネシアやクロミアを炭化珪素系不定形耐火物にも配合することが考えられる。しかしながら、マグネシアを配合して得られる炭化珪素系不定形耐火物は１４００℃未満で低融点化合物を生成するため耐火物の耐熱性が低下してしまうという問題があった。
【０００６】
また、一般的に炭化珪素系不定形耐火物は、高温度雰囲気中において、珪素成分が酸素と反応することで二酸化炭素あるいは一酸化炭素の生成、さらには酸化珪素の生成が行われるため、耐食性が低下するという問題があった。
【０００７】
また、クロミアを配合して得られる炭化珪素系不定形耐火物は耐食性は高くなるものの、使用時に六価クロムの生成が懸念され、環境保全の観点からその使用は好ましくない。このことは、クロミアを配合して得られるアルミナ系不定形耐火物についても同様に指摘される問題である。
【０００８】
一方、耐熱性及び耐食性に優れたアルミナ系不定形耐火物としては、例えば、特公平６−８２２４号公報には、所定の耐火材と、シリカ等の超微粉と、超微粉中に含有される水硬性アルミナとからなる耐火組成物に、分散剤を添加したセメント無含有不定形耐火物原料が開示されている。
【０００９】
この耐火物原料によれば、得られる耐火物の耐食性及び耐火性等が向上すると共に、流動性及び硬化性等の施工性が高められる。しかしながら、上記耐火物原料等は、硬化に適した条件の幅が狭いため、施工の際に混練現場の温度及び湿度や、骨材等配合材料の配合割合の影響を受け易く、施工性が十分でないという問題があった。具体的には、水硬性結合材は基本的に混練時に流動性が低下し易い上に、施工時の混練現場の気温が低ければ硬化不良を生じ易く、気温が高ければ硬化が早すぎて混練時の流動性が急激に低下するという問題があった。
【００１０】
すなわち、従来は、耐食性に優れると共に、安価で、製造時の施工性に優れ、さらに安全性の高い不定形耐火物は知られていなかった。
【００１１】
従って、本発明の目的は、低コストで耐食性に優れると共に、製造時の施工性に優れ、安全性の高い不定形耐火物及び該耐火物を製造可能な不定形耐火物原料を提供することにある。
【００１２】
【課題を解決するための手段】
かかる実情において、本発明者は鋭意検討を行った結果、耐火骨材及びセラミックス微粉末を用い、耐食性を向上させる添加剤として酸化ニッケル又はニッケル粉末を用いさらに無機結合剤として水硬性結合剤を用いた耐火物原料によれば、得られる不定形耐火物は、低コストで耐食性に優れると共に、製造時の施工性に優れ、さらに安全性の高いものとなることを見出し、本発明を完成するに至った。
【００１３】
また、本発明者は、特に該耐火物原料において、前記セラミックス微粉末がアルミナ質微粉末を含む耐火物原料によれば、得られる不定形耐火物中にスピネル型構造に類似するアルミナ−酸化ニッケル化合物（以下、「スピネル型アルミナ−酸化ニッケル化合物」ともいう）が生成されるため、より低コストで耐食性に優れると共に、製造時の施工性に優れ、さらに安全性の高いものとなることを見出した。
【００１４】
すなわち、本発明は、粒径が５０μｍを超えるアルミナ質耐火骨材と、平均粒径が０．１〜５０μｍのアルミナ質微粉末と、平均粒径が０．１〜１００μｍの酸化ニッケル粉末又はニッケル粉末と、水硬性アルミナと、有機繊維と、分散剤とを含み、該酸化ニッケル粉末又ニッケル粉末のＮｉＯ換算の配合量が０．７〜１８重量％である不定形耐火物原料を提供するものである。
【００１５】
また、本発明は、前記本発明の不定形耐火物原料１００重量部に対して水を４〜７重量部加え混練物とし、該混練物を、成形、乾燥及び焼成する不定形耐火物の製造方法を提供するものである。
【００１７】
【発明の実施の形態】
本発明に係る不定形耐火物原料は、耐火骨材と、セラミックス微粉末と、酸化ニッケル粉末又はニッケル粉末と、水硬性結合材とを含む不定形耐火物原料である。
【００１８】
本発明において用いられる耐火骨材としては、アルミナ質耐火骨材、炭化珪素質耐火骨材又はこれらの両方が挙げられる。このうち、アルミナ質耐火骨材は、酸化ニッケルと反応してスピネル型アルミナ−酸化ニッケル化合物を生成して不定形耐火物の耐食性が高くなるため好ましい。なお、耐火骨材として炭化珪素質耐火骨材のみを用いる場合は、後述のセラミックス微粉末にアルミナ質微粉末が含まれているものを用いると、耐火物原料中のアルミナと酸化ニッケルとでスピネル型アルミナ−酸化ニッケル化合物を生成するため、得られる耐火物の耐食性が高くなり好ましい。
【００１９】
アルミナ質耐火骨材の材質としては、例えば、高純度アルミナ、アルミナシリカ、ムライト、ボーキサイト及びシャモットより選択される１種又は２種以上が挙げられる。ここで、アルミナシリカとは主にアルミナ成分とシリカ成分とからなる組成物を広義に含むものであり、ムライトとはアルミナ成分とシリカ成分を所定の配合割合で含みムライト質となっているものをいう。上記アルミナ質耐火骨材は、アルミナ質以外に他の成分が含まれていてもよいが、アルミナ質をより高い割合で含むものが耐熱性（耐火性）の点から好ましい。また、炭化珪素質耐火骨材の材質としては、例えば、純度８０％以上の耐火物用炭化珪素が挙げられる。上記アルミナ質耐火骨材又は炭化珪素質耐火骨材は、１種又は２種以上組み合わせて用いることができる。
【００２０】
耐火骨材としては、粒径が５０μｍを越えるものが用いられ、この範囲内の粒径のものであればどのようなものでもよい。なお、粒径の異なるものを組み合わせて用いると得られる耐火物の内部組織が緻密化すると共に混練物の流動性が向上し施工部位に流し込み易くなるため好ましい。
【００２１】
例えば、耐火骨材が、粒径が１ｍｍを越えて３ｍｍ以下である粗粒材と、粒径が０．１５ｍｍを越えて１ｍｍ以下である微粒材と、粒径が５０μｍを越えて０．１５ｍｍ以下である粉末材とを組み合わせたものであると、粗粒材が耐火物の骨格を形成し、微粒材が粗粒材同士の空隙を充填し、粉末材が粗粒材及び微粒材間の空隙をさらに充填して得られる耐火物の緻密性を高めると共に混練物の流動性を高める潤滑材として作用し、また、耐火骨材全体としては得られる耐火物の内部組織が緻密化すると共に混練物の流動性が向上し施工部位に流し込み易くなるため好ましい。
【００２２】
耐火骨材の配合量としては、不定形耐火物原料中に４８〜８０重量％の量で含まれることが好ましい。耐火骨材が、粗粒材と微粒材と粉末材とからなるものである場合、不定形耐火物原料中に、粗粒材は好ましくは２５〜４５重量％、さらに好ましくは２８〜４０重量％、微粒材は好ましくは１５〜３５重量％、さらに好ましくは２０〜３０重量％、粉末材は好ましくは４〜２５重量％、さらに好ましくは５〜２２重量％の量で含まれる。粗粒材、微粒材及び粉末材が上記比率で配合されると、得られる耐火物の内部組織が緻密化すると共に、混練物の流動性が向上し施工部位に流し込み易くなるため好ましい。
【００２３】
本発明において用いられるセラミックス微粉末は、不定形耐火物原料に水を添加し混練した混練物の施工性を向上させるため、すなわち、混練物の流動性及び保水性を高くし、粘性を低くするためのものである。セラミックス微粉末としては、例えば、アルミナ質、シリカ、チタニア、ジルコニア及び炭化珪素等の微粉末が挙げられる。
【００２４】
アルミナ質微粉末の材質としては、上記アルミナ質耐火骨材と同様のものが挙げられ、例えば、高純度アルミナ、アルミナシリカ、ムライト、ボーキサイト及びシャモットより選択される１種又は２種以上が挙げられる。アルミナ質微粉末は、アルミナ質以外に他の成分が含まれいてもよいが、アルミナ質をより高い割合で含むものが耐熱性（耐火性）の点から好ましい。炭化珪素微粉末の材質としては、上記炭化珪素質耐火骨材と同様のものが挙げられ、例えば、純度８０％以上の耐火物用炭化珪素が挙げられる。
【００２５】
セラミックス微粉末のうち、アルミナ質微粉末は、混練物に流動性を付与すると共に、酸化ニッケルと反応することによりスピネル型アルミナ−酸化ニッケル化合物を生成するため好ましい。また、シリカ微粉末は混練物に流動性及び保水性を付与すると共に、耐火物の加熱後の強度を十分にするため好ましい。さらに、アルミナ質微粉末及びシリカ微粉末を組み合わせたものは、混練物の流動性及び保水性が高く、アルミナ質微粉末がスピネル型アルミナ−酸化ニッケル化合物を生成すると共に、シリカ微粉末が耐火物の加熱後の強度を十分にするためより好ましい。上記セラミックス微粉末は、１種又は２種以上組み合わせて用いることができる。
【００２６】
セラミックス微粉末は、平均粒径が０．１〜５０μｍ、好ましくは０．１〜３０μｍ、さらに好ましくは０．１〜１０μｍである。平均粒径が上記範囲内にあると、得られる耐火物の内部組織が緻密化すると共に、混練物の流動性が向上し施工部位に流し込み易くなるため好ましい。なお、アルミナ質微粉末は平均粒径が上記範囲内であり、上記アルミナ質耐火骨材とは粒径が異なっているため、本発明において特定粒径のアルミナ質粉末はアルミナ質微粉末又はアルミナ質耐火骨材のいずれかに分類される。アルミナ質微粉末は、平均粒径がアルミナ質耐火骨材よりも小さいため、不定形耐火物の焼成の際に耐火骨材間の隙間に容易に充填される。このため、該隙間で酸化ニッケルと反応して耐食性に富むスピネル型アルミナ−酸化ニッケル化合物を生成し、一般的に該隙間で生じ易いスラグの浸漬をより効果的に抑制できて好ましい。
【００２７】
セラミックス微粉末は、不定形耐火物原料中に好ましくは１２〜２７重量％、さらに好ましくは１４〜２７重量％の量で含まれる。セラミックス微粉末の配合量が１２重量％未満であると不定形耐火物原料の混練物の流動性及び保水性が十分でないため好ましくない。なお、この状態の混練物に対して、流動性及び保水性を付与するために混練水量を多くすると、耐火骨材とセラミックス微粉末とが分離し易くなるため好ましくない。また、セラミックス微粉末の配合量が２７重量％を越えると不定形耐火物原料の混練物に振動を加えた際の流動性は向上するが、混練物の粘性が増加しすぎて施工性が悪化するため好ましくない。
【００２８】
セラミックス微粉末がアルミナ質微粉末及びシリカ微粉末の併用系である場合、不定形耐火物原料中、アルミナ質微粉末の配合量は好ましくは８〜２６．５重量％、さらに好ましくは１０〜２５重量％、シリカ微粉末の配合量は好ましくは０．５〜１０重量％、さらに好ましくは１．５〜７重量％の量である。アルミナ質微粉末及びシリカ微粉末の配合量が上記範囲内にあると、流動性、保水性及び粘性のバランスに優れた混練物が得られる。
【００２９】
本発明において用いられる酸化ニッケル粉末又はニッケル粉末は、不定形耐火物にスラグに対する耐食性を付与するためのものである。このうち酸化ニッケル粉末としては、例えば、触媒、ガラス着色、ほうろう、陶磁器釉薬及びフェライト材等に用いられるニッケル換算で７５重量％以上の粉末が挙げられる。また、ニッケル粉末としては、例えば、酸化雰囲気中での加熱により酸化ニッケルを生成するものが挙げられる。ここで、酸化雰囲気中での加熱とは、例えば、混練成形物の空気中での焼成工程における加熱や、乾燥だき、又は焼成後の耐火物を炉内で使用する際における加熱等が挙げられる。
【００３０】
酸化ニッケル粉末又はニッケル粉末は、平均粒径が０．１〜１００μｍ、好ましくは０．３〜３０μｍのものが用いられる。平均粒径が該範囲内にあると、酸化ニッケル又はニッケル粉末が焼成等の際に酸化されて生成した酸化ニッケルが、アルミナ質微粉末又はアルミナ質骨材と反応して効果的にスピネル型アルミナ−酸化ニッケル化合物を生成し、不定形耐火物のスラグに対する耐浸食性が高くなるため好ましい。
【００３１】
酸化ニッケル粉末又はニッケル粉末は、ＮｉＯ換算の重量が、不定形耐火物原料中に好ましくは０．７〜１８重量％、さらに好ましくは１〜１５重量％、特に好ましくは１．５〜５重量％、さらに特に好ましくは１．８〜４．５重量％の量で含まれる。
【００３２】
上記配合量が０．７重量％未満であると、得られる不定形耐火物の耐食性が十分に向上しないため好ましくない。また、上記配合量が０．７重量％以上１．８重量％未満であると、配合量が微量で品質の安定性が低下するおそれがあるため、施工時の品質の安定性を重視する場合には、上記配合量が１．８重量％以上であることがより好ましい。また、上記配合量が１８重量％を越えると、耐食性の改善作用が一定以上向上しないため不経済であると共に、焼成時に成形体が大きく膨張し施工体に亀裂を生じ易くなるため好ましくない。
【００３３】
図５に、本発明に係る不定形耐火物のうちのアルミナ−酸化ニッケル系不定形耐火物における、酸化ニッケル粉末の添加量と浸食指数及び平均細孔径との関係の一例を示す。図５より、酸化ニッケルの粉末の配合比率が高くなると、不定形耐火物の耐食性が高くなると共に平均細孔径が小さくなることが分かる。これより、不定形耐火物の耐食性、特にアルミナ−酸化ニッケル系不定形耐火物の耐食性は、アルミナと酸化ニッケルとが反応してスピネル型アルミナ−酸化ニッケル化合物を生成することにより不定形耐火物の細孔径が小さくなり、溶融スラグが浸食し難い構造になるため向上すると考えられる。
【００３４】
本発明において用いられる水硬性結合材としては、特に限定されないが、例えば、水硬性アルミナ、アルミナセメント等が挙げられる。このうち水硬性アルミナは、ＣａＯを含まないため得られる不定形耐火物を高温下で繰り返し使用しても耐食性が特に低下し難いと共に、アルミナ成分が酸化ニッケルと反応してスピネル型アルミナ−酸化ニッケル化合物の生成に寄与するため好ましい。水硬性結合材は、平均粒径が１〜２０μｍ、好ましくは１０〜１５μｍである。平均粒径が上記範囲内にあると、施工可能な流動性を混練後３０分以上保つことができるため好ましい。
【００３５】
水硬性結合材は、不定形耐火物原料中に好ましくは２〜１０重量％、さらに好ましくは２〜５重量％の量で含まれる。水硬性結合材の配合量が２重量％未満であると施工時の気温が低い場合に硬化不良を生じることがあるため、また、１０重量％を越えると施工時の気温が高い場合に硬化が早すぎて混練時における流動性が急激に低下するおそれがあるため好ましくない。
【００３６】
本発明に係る不定形耐火物原料には、さらに、有機繊維や分散剤を適宜配合してもよい。有機繊維としては、例えば、ポリプロピレン、アクリル、レーヨン、ナイロン及びビニロン等が挙げられ、これらを１種又は２種以上組み合わせて用いることができる。有機繊維を配合すると、急速加熱時の施工体の爆裂を防止できるため好ましい。有機繊維の配合量は、耐火骨材、酸化ニッケル粉末又はニッケル粉末のＮｉＯ換算の重量、セラミックス微粉末及び水硬性結合材の合計量１００重量部に対し、０．０４〜０．１重量部である。
【００３７】
分散剤としては、例えば、金属キレート化合物、アルカリ金属炭酸塩、芳香族スルホン酸ホルマリン縮合塩等が挙げられ、これらを１種又は２種以上組み合わせて用いることができる。分散剤を配合すると、低水量での混練物の流動性が向上し、混練が可能となるため好ましい。分散剤の配合量は、耐火骨材、酸化ニッケル粉末又はニッケル粉末のＮｉＯ換算の重量、セラミックス微粉末及び水硬性結合材の合計量１００重量部に対し、０．０５〜０．５重量部である。分散剤の配合量が、上記範囲内であると、不定形耐火物原料の混練物の流動性が長く維持されるため好ましい。本発明に係る不定形耐火物原料は、上記耐火骨材、酸化ニッケル粉末又はニッケル粉末、セラミックス微粉末及び水硬性結合材、さらに必要により有機繊維又は分散剤等を配合して混合して得られる。これら諸原料は、一回で又は複数回に分けて混合してもよく、複数回に分けて混合する場合は混合する順序を問わない。
【００３８】
本発明に係る不定形耐火物原料には、耐火物の耐食性をより高めるために、さらにジルコニア、チタニア、酸化マンガン及び酸化コバルトより選択される１種又は２種以上を配合してもよい。
【００３９】
上記本発明に係る不定形耐火物原料は、少なくともセラミックス微粉末がアルミナ質微粉末を含むことが好ましく、さらにセラミックス微粉末がアルミナ質微粉末を含み且つ耐火骨材がアルミナ質耐火骨材を含むことがより好ましい。不定形耐火物原料中にアルミナ質微粉末が含まれていると、アルミナ質微粉末が不定形耐火物の焼成の際に耐火骨材間の隙間に容易に充填され、焼成の際又は溶融炉等を使用する際に、該隙間で酸化ニッケルと反応して耐食性に富むスピネル型アルミナ−酸化ニッケル化合物を生成するため、一般的に該隙間で生じ易いスラグの浸漬を効果的に抑制できて耐食性がより高くなるので好ましい。また、アルミナ質微粉末に加えさらにアルミナ質耐火骨材が含まれると、アルミナ質耐火骨材が特に粉末材である場合には、粉末材が粗粒材や微粒材で形成される空隙においてスピネル型アルミナ−酸化ニッケル化合物を生成するため、耐食性がより高くなり好ましい。
【００４０】
本発明に係る不定形耐火物原料がアルミナ質微粉末を含む場合、不定形耐火物原料は、通常、アルミナ質微粉末を８〜２７重量％、酸化ニッケル粉末又はニッケル粉末をＮｉＯ換算で０．７〜１８重量％及び水硬性結合材を２〜１０重量％含み、好ましくは、アルミナ質微粉末を１０〜２５重量％、酸化ニッケル粉末又はニッケル粉末をＮｉＯ換算で１〜１５重量％及び水硬性結合材を２〜５重量％含む。アルミナ質微粉末と、酸化ニッケル粉末等とが該比率で含まれると、スピネル型アルミナ−酸化ニッケル化合物が生成され易く、耐食性がより高くなるため好ましい。
【００４１】
また、本発明に係る不定形耐火物原料がアルミナ質微粉末を含み且つアルミナ質耐火骨材を含む場合、不定形耐火物原料は、通常、アルミナ質微粉末を８〜２７重量％、アルミナ質耐火骨材を４８〜８０重量％、酸化ニッケル粉末又はニッケル粉末をＮｉＯ換算で０．７〜１８重量％及び水硬性結合材を２〜１０重量％含み、好ましくは、アルミナ質微粉末を１０〜２５重量％、アルミナ質耐火骨材を５５〜８０重量％、酸化ニッケル粉末又はニッケル粉末をＮｉＯ換算で１〜１５重量％及び水硬性結合材を２〜５重量％含む。アルミナ質微粉末、アルミナ質耐火骨材及び酸化ニッケル粉末等が該比率で含まれると、スピネル型アルミナ−酸化ニッケル化合物が生成され易く、耐食性がより高くなるため好ましい。
【００４２】
本発明に係る不定形耐火物は、上記不定形耐火物原料に水を加え混練物とし、さらに該混練物を焼成して得られる。この際の水の添加量は、上記不定形耐火物原料１００重量部に対して水が通常４〜７重量部、好ましくは５〜６重量部である。水の添加量が４重量部未満であると混練物の流動性が低く、混練が困難になり易いため好ましくなく、７重量部を越えると混練物の流動性が高くなりすぎ、耐火骨材とセラミックス微粉末とが分離し易くなるため好ましくない。
【００４３】
混練物とするには、例えば、ミキサー等を用いて行う。本発明に係る不定形耐火物は、混練物としたときに、上記不定形耐火物原料と水とを上記配合量比で混練してなるため流動性に優れる。また、さらに分散剤が上記範囲内の量で配合されているため、特に混練物の流動性が長く維持され、使用可能時間が長くなる。
【００４４】
本発明に係る不定形耐火物は、上記混練物を適宜、成形、乾燥及び焼成して得られる。例えば、混練物を型に入れて成形し、所定の形状の成形体とした後、乾燥、焼成して不定形耐火物を得ることができる。成形方法としては、例えば、施工現場における型枠への振動流し込み成形や厚塗りが挙げられる。乾燥は、例えば、８０〜１２０℃で１７〜２４時間行う。焼成は、例えば、１２００〜１５００℃で５〜２４時間行う。また、本発明に係る不定形耐火物は、耐火物を作製するための上記焼成工程を特に設けることなく、乾燥体のまま溶融炉の内壁等に施工し、溶融炉等を使用する際の熱で実質的に焼成することにより得ることもできる。なお、必要により配合された有機繊維や分散剤は焼成後には焼失し、不定形耐火物中には存在しない。
【００４５】
本発明に係る不定形耐火物は、耐食性及び耐熱性に優れる。特に、アルミナ質微粉末を含む不定形耐火物原料や、アルミナ質微粉末を含み且つアルミナ質耐火骨材を含む不定形耐火物原料より得られる不定形耐火物は、不定形耐火物原料における耐火骨材間の隙間等にスピネル型アルミナ−酸化ニッケル化合物を含むため、より耐食性及び耐熱性に優れる。上記本発明に係る不定形耐火物原料及び該不定形耐火物原料から製造された不定形耐火物は、溶鉱取鍋用耐火物や、灰溶融炉用耐火物の用途に使用することができる。
【００４６】
【実施例】
次に、実施例を挙げて、本発明を更に具体的に説明するが、これは単に例示であって、本発明を制限するものではない。
【００４７】
実施例１
粒径が１ｍｍを越えて３ｍｍ以下であるアルミナ質耐火骨材の粗粒材３１．０重量部、粒径が０．１５ｍｍを越えて１ｍｍ以下であるアルミナ質耐火骨材の微粒材２７．１重量部、粒径が５０μｍを越えて０．１５ｍｍ以下であるアルミナ質耐火骨材の粉末材１０．４重量部、平均粒径１μm の酸化ニッケル粉末１０．０重量部、平均粒径２μm のアルミナ超微粉末１６．０重量部、平均粒径０．６μm のシリカ超微粉末１．５重量部、及び平均粒径１０μm の水硬性アルミナ４．０重量部の合計１００．０重量部に、有機繊維０．０８重量部、分散剤０．１重量部及び水６．０重量部を添加し、これらの混合物をミキサーで６分間混練した。得られた混練物の流動性を以下に示す振動フロー値として評価した。配合量及び振動フロー値の結果を表１に示す。表１中、配合量は重量部で表す。
次に、混練物を鋳込み成形し、１０５℃で２４時間乾燥し、さらに１４００℃で５時間焼成し不定形耐火物を得た。得られた不定形耐火物の耐食性を以下に示す浸食指数として評価した。結果を表１に示す。
【００４８】
〔振動フロー値の測定方法〕
まず、振動テーブル上に、JIS R 5201:92 に規定されたフローコーンをコーンの先端部が上を向くように載置し、該フローコーン内に適宜振動を与えつつ混練物を充填した。次に、充填された混練物の形状を崩さないようにゆっくりとコーンを除去した後、速やかに６０Hzの振動を３０秒間与えた。振動終了後、崩れて広がった混練物の底面における直径の最大値と、該最大値部分に垂直方向の部分の直径との２箇所を測定し、２箇所の平均値を振動フロー値（ｍｍ）とした。振動フロー値は、値が大きいほうが流動性が良好と評価した。
【００４９】
〔浸食指数の測定方法〕
まず、図１のような等脚台形柱状（台形面の上底５５ｍｍ、台形面の下底１３０ｍｍ、台形面の高さ６５ｍｍ、台形柱の高さ１１５ｍｍ）の不定形耐火物からなる試験サンプルＡを作製し、図２のようにサンプルＡの６個を上底側の矩形面の６面で六角柱状の凹部Ｄを形成するように組み合わせて固定し外観が六角柱状の試験体Ｂを構成した。なお、図１中の数値は寸法を示し、単位はｍｍである。次に、図２のように試験体Ｂを横に倒した状態で、且つ、試験体Ｂが底面に垂直な軸を中心として回転装置Ｃにより図２の矢印Ｘの一定方向に回転する状態にし、試験体Ｂの凹部Ｄ内にスラグＥを装入し、１５００℃下で８時間回転させた。
８時間経過後、試験体Ｂを各サンプルＡごとにバラし、図３のようにサンプルＡをスラグが接触した上底側矩形面の長手方向の中心線ａｂから下底側矩形面の長手方向の中心線ｃｄへ略矩形の切断面ａｂｄｃが現れるように切断した。次に、図４のように該切断面ａｂｄｃのスラグによる浸食部Ｆの浸食面積を測定し、下記式（１）により浸食率を算出した。
浸食率（％）＝（断面の浸食部の面積／断面の全面積）×１００ （１）
次に、得られた対象サンプルの浸食率と、標準サンプル（従来のアルミナセメントを結合材として焼成された不定形耐火物）の浸食率とから、下記式（２）により浸食指数を算出した。標準サンプルの組成と物性について、表１に示す。
【００５０】
【表１】
比較例１
水硬性アルミナ４．０重量部に代えて、アルミナセメント４．０重量部を用いた以外は実施例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表１に示す。
【００５２】
比較例２
酸化ニッケルを配合せず、アルミナ質耐火骨材の粉末材を２０．４重量部とした以外は実施例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表１に示す。
【００５３】
実施例２〜４、比較例３、４
表２に示すように、酸化ニッケル粉末等の配合量を変えた以外は、実施例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表２に示す。なお、比較例４は成形体に亀裂が発生したため浸食試験が不可能であった。
【００５４】
【表２】
参考例１
粒径が１ｍｍを越えて３ｍｍ以下であるＳｉＣ（炭化珪素）質耐火骨材の粗粒材３１．０重量部、粒径が０．１５ｍｍを越えて１ｍｍ以下であるＳｉＣ質耐火骨材の微粒材２７．１重量部、粒径が５０μｍを越えて０．１５ｍｍ以下であるＳｉＣ質耐火骨材の粉末材１８．４重量部、平均粒径１μｍの酸化ニッケル粉末２．０重量部、平均粒径２μｍのアルミナ超微粉末１６．０重量部、平均粒径０．６μｍのシリカ超微粉末１．５重量部、及び平均粒径１０μｍの水硬性アルミナ４．０重量部の合計１００．０重量部に、有機繊維０．０８重量部、分散剤０．１重量部及び水６．０重量部を添加し、これらの混合物をミキサーで６分間混練した。得られた混練物の流動性を実施例１と同様に振動フロー値として評価した。配合量及び振動フロー値の結果を表３に示す。表３中、配合量は重量部で表す。次に、実施例１と同様にして混練物から不定形耐火物を得た。得られた不定形耐火物の耐食性を実施例１と同様に浸食指数として評価した。結果を表３に示す。
【００５６】
【表３】
比較例５
水硬性アルミナ４．０重量部に代えて、アルミナセメント４．０重量部を用いた以外は参考例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表３に示す。
【００５８】
比較例６
酸化ニッケルを配合せず、ＳｉＣ質耐火骨材の粉末材を２０．４重量部とした以外は参考例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表３に示す。
【００５９】
参考例２
表３に示すように、酸化ニッケル粉末等の配合量を変えた以外は、参考例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値及び浸食指数の結果を表３に示す。
【００６０】
実施例５〜７、比較例７
表４に示すように、酸化ニッケル粉末等の配合量を変えた以外は、実施例１と同様にして混練物及び不定形耐火物を得、これらを実施例１と同様にして評価した。原料等の配合量、振動フロー値、浸食指数及び平均細孔径の結果を表４及び図５に示す。なお、平均細孔径は、得られた不定形耐火物を切断して小片を作製し、水銀ポロシメータによって測定した。
【００６１】
【表４】
表１より、アルミナ系不定形耐火材の実施例１は、アルミナセメントを用いた比較例１又は酸化ニッケル粉末を配合しなかった比較例２のいずれよりも浸食指数が小さく、耐食性に優れる。また、表２より、酸化ニッケルの含有量が少なくとも０．７〜１８重量％の範囲内において、流動性及び耐食性のバランスが優れる。
【００６３】
表４及び図５より、アルミナ系不定形耐火材の実施例５〜７は、比較例７よりも平均細孔径及び浸食指数が小さく耐食性に優れると共に、流動性と耐食性のバランスに優れることが分かる。また、表４及び図５より、アルミナ質耐火骨材及びアルミナ微粉末に対して酸化ニッケル微粉末を配合することで、平均細孔径が小さくなり、それに伴い耐食性が高くなることが分かる。図５の平均細孔径と耐食性との関係は、生成されたスピネル型アルミナ−酸化ニッケル化合物によって、得られるアルミナ系不定形耐火物中の空隙が埋められ、そのことでスラグの浸漬が抑制されることを示唆するものであるといえる。
【００６４】
【発明の効果】
本発明に係る不定形耐火物原料に所定の混練水を添加すると流動性に優れた混練物を低コストで得ることができ、該混練物を焼成して得られる不定形耐火物は耐食性に優れる。すなわち、低コストで耐食性に優れる不定形耐火物を優れた施工性の下製造することができる。
【図面の簡単な説明】
【図１】浸食試験におけるサンプル形状を示す斜視図である。
【図２】浸食試験を示す模式図である。
【図３】浸食率の評価方法を示す模式図である。
【図４】浸食率の評価方法を示す模式図である。
【図５】酸化ニッケル添加量と、浸食指数及び平均細孔径との関係を示すグラフである。
【符号の説明】
Ａ 不定形耐火物のサンプル
Ｂ 六角柱状の試験体
Ｃ 回転装置
Ｄ 凹部
Ｅ スラグ
Ｆ 浸食部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an amorphous refractory raw material of alumina-nickel oxide type and silicon carbide-alumina-nickel oxide type having excellent corrosion resistance against slag, and an amorphous refractory produced from the refractory raw material.
[0002]
[Prior art]
Conventionally, as an amorphous refractory, alumina-based amorphous refractory mainly composed of alumina aggregate and silicon carbide-based amorphous refractory mainly composed of alumina carbide, using alumina cement as an inorganic binder. It has been known. Both the alumina-based amorphous refractory and the silicon carbide-based amorphous refractory are excellent in heat resistance. In particular, the silicon carbide-based amorphous refractory has low permeability to basic molten slag and excellent corrosion resistance. These refractories are widely used as refractories for a ladle ladle.
[0003]
In recent years, the above-mentioned amorphous refractories have been considered for use as melting furnace refractories. However, since the refractory for melting furnaces is in direct contact with the basic molten slag, the requirement for corrosion resistance is severer than that for refractories for ladle ladle. For this reason, even if the conventional amorphous refractory is a silicon carbide type irregular refractory having relatively excellent corrosion resistance, the corrosion resistance is not sufficient as a refractory for a melting furnace.
[0004]
In order to solve such problems, Japanese Patent Application Laid-Open No. 9-278540 discloses a silicon carbide-based amorphous refractory material fired by adding carbon and cobalt oxide. According to this refractory material, corrosion resistance is disclosed. Can be further improved. However, since the cobalt oxide used in the above refractory is expensive, there is a problem that the amorphous refractory produced is also expensive.
[0005]
[Problems to be solved by the invention]
As a method of improving the corrosion resistance without using cobalt oxide, for example, magnesia or chromia that is already used in alumina-based amorphous refractories and imparts high corrosion resistance to refractories is also blended into silicon carbide-based amorphous refractories. Can be considered. However, the silicon carbide amorphous refractory obtained by blending magnesia has a problem that the heat resistance of the refractory is lowered because a low melting point compound is formed at less than 1400 ° C.
[0006]
Also, silicon carbide-based amorphous refractories generally have a corrosion resistance because the silicon component reacts with oxygen in the high temperature atmosphere to generate carbon dioxide or carbon monoxide, and further silicon oxide. There was a problem that decreased.
[0007]
In addition, although the silicon carbide amorphous refractory obtained by blending chromia has high corrosion resistance, there is a concern about the formation of hexavalent chromium at the time of use, and its use is not preferable from the viewpoint of environmental protection. This is also a problem pointed out in the same way for alumina-based amorphous refractories obtained by blending chromia.
[0008]
On the other hand, as an alumina-based amorphous refractory having excellent heat resistance and corrosion resistance, for example, Japanese Patent Publication No. 6-8224 contains a predetermined refractory material, ultrafine powder such as silica, and ultrafine powder. A cement-free amorphous refractory raw material in which a dispersant is added to a refractory composition comprising hydraulic alumina is disclosed.
[0009]
According to this refractory raw material, the corrosion resistance and fire resistance of the obtained refractory are improved, and workability such as fluidity and curability is improved. However, the above-mentioned refractory raw materials have a narrow range of conditions suitable for curing, so they are easily affected by the temperature and humidity at the kneading site and the blending ratio of blended materials such as aggregates during construction, and workability is sufficient. There was a problem of not. Specifically, hydraulic binders are basically prone to fluidity during kneading, and also tend to cause poor curing if the temperature at the kneading site during construction is low, and kneading because the curing is too fast. There was a problem that the fluidity of the time dropped rapidly.
[0010]
That is, heretofore, an amorphous refractory that is excellent in corrosion resistance, inexpensive, excellent in workability during manufacture, and high in safety has not been known.
[0011]
Accordingly, an object of the present invention is to provide an amorphous refractory material that is low in cost and excellent in corrosion resistance, excellent in workability during manufacturing, and highly safe, and an amorphous refractory material capable of producing the refractory. is there.
[0012]
[Means for Solving the Problems]
In this situation, the present inventors have conducted intensive studies, and as a result, used refractory aggregates and fine ceramic powder, used nickel oxide or nickel powder as an additive to improve corrosion resistance, and used a hydraulic binder as an inorganic binder. According to the refractory raw material, the obtained amorphous refractory is found to be low in cost and excellent in corrosion resistance, excellent in workability at the time of manufacture, and further high in safety. It came.
[0013]
Further, the present inventor, in particular, in the refractory raw material, according to the refractory raw material in which the ceramic fine powder contains alumina fine powder, the amorphous refractory obtained has an alumina-nickel oxide similar to a spinel structure. Since a compound (hereinafter also referred to as “spinel-type alumina-nickel oxide compound”) is produced, it is found that the cost is excellent at low cost and the corrosion resistance is excellent, the workability at the time of manufacture is excellent, and the safety is high. It was.
[0014]
That is, the present inventionAlumina with particle size over 50μmWith refractory aggregateAlumina with an average particle size of 0.1 to 50 μmFine powder,The average particle size is 0.1-100 μmNickel oxide powder or nickel powder and hydraulicAlumina, organic fiber and dispersantAndThe nickel oxide powder or the nickel powder content in terms of NiO is 0.7 to 18% by weight.It provides an amorphous refractory raw material.
[0015]
The present invention also provides:4 to 7 parts by weight of water is added to 100 parts by weight of the amorphous refractory raw material of the present invention to prepare a kneaded product, and the kneaded product is molded, dried, and fired.Is to provide.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The amorphous refractory raw material according to the present invention is an amorphous refractory raw material containing a refractory aggregate, ceramic fine powder, nickel oxide powder or nickel powder, and a hydraulic binder.
[0018]
Examples of the refractory aggregate used in the present invention include alumina refractory aggregate, silicon carbide refractory aggregate, or both. Of these, the alumina-based refractory aggregate is preferable because it reacts with nickel oxide to form a spinel-type alumina-nickel oxide compound, thereby increasing the corrosion resistance of the amorphous refractory. When only a silicon carbide refractory aggregate is used as the refractory aggregate, if the ceramic fine powder described later contains alumina fine powder, the spinel is composed of alumina and nickel oxide in the refractory raw material. Since a type | mold alumina-nickel oxide compound is produced | generated, the corrosion resistance of the obtained refractory becomes high and is preferable.
[0019]
Examples of the material for the alumina refractory aggregate include one or more selected from high-purity alumina, alumina silica, mullite, bauxite, and chamotte. Here, the alumina silica broadly includes a composition composed mainly of an alumina component and a silica component, and mullite includes an alumina component and a silica component at a predetermined blending ratio and has a mullite quality. Say. The alumina refractory aggregate may contain other components in addition to the alumina, but those containing alumina at a higher ratio are preferable from the viewpoint of heat resistance (fire resistance). Moreover, as a material of the silicon carbide refractory aggregate, for example, silicon carbide for refractories having a purity of 80% or more can be cited. The alumina-based refractory aggregate or the silicon carbide-based refractory aggregate can be used alone or in combination of two or more.
[0020]
As the refractory aggregate, those having a particle size exceeding 50 μm are used, and any material having a particle size within this range may be used. In addition, it is preferable to use a combination of particles having different particle diameters because the internal structure of the refractory obtained is densified and the flowability of the kneaded material is improved so that it can be easily poured into a construction site.
[0021]
For example, the refractory aggregate is a coarse particle having a particle size of more than 1 mm and 3 mm or less, a fine particle having a particle size of more than 0.15 mm and 1 mm or less, and a particle size of more than 50 μm and 0.15 mm. When combined with the following powder material, the coarse material forms a refractory skeleton, the fine material fills the gaps between the coarse material, and the powder material is between the coarse material and the fine material Acts as a lubricant to improve the denseness of the refractory obtained by further filling the voids and increase the fluidity of the kneaded product, and the refractory aggregate as a whole becomes denser and the internal structure of the refractory obtained is kneaded. It is preferable because the fluidity of the material is improved and the material can be easily poured into the construction site.
[0022]
As a compounding quantity of a refractory aggregate, it is preferable to contain in the quantity of 48 to 80 weight% in an amorphous refractory raw material. When the refractory aggregate is composed of coarse particles, fine particles, and powder material, the coarse particles are preferably 25 to 45% by weight, more preferably 28 to 40% by weight in the amorphous refractory material. The fine particle material is preferably contained in an amount of 15 to 35% by weight, more preferably 20 to 30% by weight, and the powder material is preferably contained in an amount of 4 to 25% by weight, more preferably 5 to 22% by weight. It is preferable that the coarse material, the fine material and the powder material are blended in the above ratio because the internal structure of the obtained refractory is densified and the fluidity of the kneaded material is improved and can be easily poured into the construction site.
[0023]
The ceramic fine powder used in the present invention improves the workability of the kneaded material obtained by adding water to the amorphous refractory raw material and kneaded, that is, increases the fluidity and water retention of the kneaded material and lowers the viscosity. Is for. Examples of the ceramic fine powder include fine powders such as alumina, silica, titania, zirconia, and silicon carbide.
[0024]
Examples of the material of the alumina fine powder include the same materials as the above-mentioned alumina-based refractory aggregate, and examples thereof include one or more selected from high-purity alumina, alumina silica, mullite, bauxite, and chamotte. . The alumina fine powder may contain other components in addition to the alumina, but those containing alumina at a higher ratio are preferable from the viewpoint of heat resistance (fire resistance). Examples of the material of the silicon carbide fine powder include the same materials as the above-mentioned silicon carbide refractory aggregate, and examples thereof include silicon carbide for refractories having a purity of 80% or more.
[0025]
Among the ceramic fine powders, the alumina fine powder is preferable because it imparts fluidity to the kneaded material and generates a spinel type alumina-nickel oxide compound by reacting with nickel oxide. Silica fine powder is preferable because it imparts fluidity and water retention to the kneaded product and also provides sufficient strength after heating the refractory. Furthermore, the combination of the alumina fine powder and the silica fine powder has high fluidity and water retention of the kneaded product, the alumina fine powder generates a spinel type alumina-nickel oxide compound, and the silica fine powder is a refractory. It is more preferable to ensure sufficient strength after heating. The ceramic fine powder can be used alone or in combination of two or more.
[0026]
The ceramic fine powder has an average particle size of 0.1 to 50 μm, preferably 0.1 to 30 μm, and more preferably 0.1 to 10 μm. When the average particle size is in the above range, the internal structure of the obtained refractory is densified, and the fluidity of the kneaded material is improved, so that it can be easily poured into the construction site. The alumina fine powder has an average particle size within the above range, and the particle size is different from that of the alumina refractory aggregate. Therefore, in the present invention, the alumina powder having a specific particle size is alumina fine powder or alumina. Classified as one of quality refractory aggregates. Since the alumina fine powder has an average particle size smaller than that of the alumina refractory aggregate, it is easily filled in the gaps between the refractory aggregates when firing the amorphous refractory. For this reason, it reacts with nickel oxide in the gap to produce a spinel-type alumina-nickel oxide compound rich in corrosion resistance, and the immersion of slag that generally tends to occur in the gap can be more effectively suppressed, which is preferable.
[0027]
The ceramic fine powder is preferably contained in the amorphous refractory raw material in an amount of 12 to 27% by weight, more preferably 14 to 27% by weight. If the blending amount of the ceramic fine powder is less than 12% by weight, the flowability and water retention of the kneaded material of the amorphous refractory material are not sufficient. In addition, it is not preferable to increase the amount of kneading water for imparting fluidity and water retention to the kneaded material in this state because the fireproof aggregate and the ceramic fine powder are easily separated. In addition, if the amount of the ceramic fine powder exceeds 27% by weight, the fluidity when vibration is applied to the kneaded material of the irregular refractory material is improved, but the viscosity of the kneaded material increases too much and the workability deteriorates. Therefore, it is not preferable.
[0028]
When the ceramic fine powder is a combined system of alumina fine powder and silica fine powder, the amount of the alumina fine powder in the amorphous refractory raw material is preferably 8 to 26.5% by weight, more preferably 10 to 25%. The blending amount of the wt% silica fine powder is preferably 0.5 to 10 wt%, more preferably 1.5 to 7 wt%. When the blending amount of the alumina fine powder and the silica fine powder is within the above range, a kneaded material having an excellent balance of fluidity, water retention and viscosity can be obtained.
[0029]
The nickel oxide powder or nickel powder used in the present invention is for imparting corrosion resistance to slag to an amorphous refractory. Among these, examples of the nickel oxide powder include powders of 75% by weight or more in terms of nickel used for catalysts, glass coloring, enamels, ceramic glazes, ferrite materials and the like. Moreover, as nickel powder, what produces | generates nickel oxide by the heating in oxidizing atmosphere is mentioned, for example. Here, the heating in the oxidizing atmosphere includes, for example, heating in the firing step of the kneaded molded product in the air, drying when used, or heating when using the fired refractory in the furnace. .
[0030]
The nickel oxide powder or nickel powder has an average particle size of 0.1 to 100 μm, preferably 0.3 to 30 μm. When the average particle size is within this range, the nickel oxide or nickel powder is fired.etcThe nickel oxide produced by oxidation during the reaction reacts with the alumina fine powder or the alumina aggregate to effectively produce a spinel type alumina-nickel oxide compound, and the erosion resistance to the slag of the amorphous refractory is improved. Since it becomes high, it is preferable.
[0031]
The nickel oxide powder or nickel powder has a NiO equivalent weight of preferably 0.7 to 18% by weight, more preferably 1 to 15% by weight, particularly preferably 1.5 to 5% by weight in the amorphous refractory raw material. More particularly preferably, it is contained in an amount of 1.8 to 4.5% by weight.
[0032]
When the blending amount is less than 0.7% by weight, the corrosion resistance of the obtained amorphous refractory is not sufficiently improved, which is not preferable. Also, if the blending amount is 0.7 wt% or more and less than 1.8 wt%, the blending amount is very small and the stability of quality may be lowered. More preferably, the blending amount is 1.8% by weight or more. On the other hand, if the blending amount exceeds 18% by weight, the effect of improving the corrosion resistance is not improved more than a certain level, which is uneconomical, and the molded body is greatly expanded during firing and cracks are likely to occur in the construction body.
[0033]
FIG. 5 shows an example of the relationship between the addition amount of nickel oxide powder, the erosion index, and the average pore diameter in the alumina-nickel oxide amorphous refractories of the amorphous refractories according to the present invention. As can be seen from FIG. 5, when the mixing ratio of the nickel oxide powder increases, the corrosion resistance of the amorphous refractory increases and the average pore diameter decreases. Accordingly, the corrosion resistance of the amorphous refractory, particularly the corrosion resistance of the alumina-nickel oxide-based amorphous refractory, is determined by reacting alumina with nickel oxide to form a spinel type alumina-nickel oxide compound. It is considered that the pore diameter is reduced and the molten slag is hard to erode so that the structure is improved.
[0034]
Although it does not specifically limit as a hydraulic binder used in this invention, For example, a hydraulic alumina, an alumina cement, etc. are mentioned. Among these, hydraulic alumina does not contain CaO, so that the corrosion resistance is not particularly lowered even when the amorphous refractory obtained is repeatedly used at high temperatures, and the alumina component reacts with nickel oxide to cause spinel type alumina-nickel oxide. Since it contributes to the production | generation of a compound, it is preferable. The hydraulic binder has an average particle size of 1 to 20 μm, preferably 10 to 15 μm. It is preferable that the average particle size is within the above range because the workable fluidity can be maintained for 30 minutes or more after kneading.
[0035]
The hydraulic binder is preferably contained in the amorphous refractory raw material in an amount of 2 to 10% by weight, more preferably 2 to 5% by weight. If the blending amount of the hydraulic binder is less than 2% by weight, curing may occur when the temperature during construction is low, and if it exceeds 10% by weight, curing may occur when the temperature during construction is high. Since it is too early and the fluidity at the time of kneading may decrease rapidly, it is not preferable.
[0036]
The amorphous refractory material according to the present invention may further contain organic fibers and a dispersant as appropriate. Examples of the organic fiber include polypropylene, acrylic, rayon, nylon, and vinylon, and these can be used alone or in combination of two or more. When organic fiber is blended, it is preferable because explosion of the construction body during rapid heating can be prevented. The compounding amount of the organic fiber is 0.04 to 0.1 parts by weight with respect to 100 parts by weight of the total amount of refractory aggregate, nickel oxide powder or nickel powder in terms of NiO conversion, ceramic fine powder and hydraulic binder. is there.
[0037]
Examples of the dispersant include metal chelate compounds, alkali metal carbonates, aromatic sulfonic acid formalin condensed salts, and the like, and these can be used alone or in combination. It is preferable to add a dispersant because the fluidity of the kneaded product with a low amount of water is improved and kneading becomes possible. The blending amount of the dispersant is 0.05 to 0.5 parts by weight with respect to refractory aggregate, nickel oxide powder or NiO equivalent weight of the nickel powder, and 100 parts by weight of the total amount of ceramic fine powder and hydraulic binder. is there. It is preferable that the blending amount of the dispersant is within the above range because the fluidity of the kneaded material of the amorphous refractory material is maintained for a long time. The amorphous refractory raw material according to the present invention is obtained by mixing and mixing the above-mentioned refractory aggregate, nickel oxide powder or nickel powder, ceramic fine powder and hydraulic binder, and if necessary organic fiber or dispersant. . These raw materials may be mixed at one time or divided into a plurality of times, and when mixed in a plurality of times, the mixing order is not limited.
[0038]
In order to further enhance the corrosion resistance of the refractory, the amorphous refractory material according to the present invention may further contain one or more selected from zirconia, titania, manganese oxide and cobalt oxide.
[0039]
In the above-mentioned amorphous refractory material according to the present invention, at least the ceramic fine powder preferably contains an alumina fine powder, the ceramic fine powder contains an alumina fine powder, and the refractory aggregate contains an alumina refractory aggregate. It is more preferable. If the amorphous refractory raw material contains alumina fine powder, the alumina fine powder is easily filled in the gaps between the refractory aggregates during firing of the amorphous refractory, and the firing or melting furnace Etc., in order to produce spinel type alumina-nickel oxide compound rich in corrosion resistance by reacting with nickel oxide in the gap, it is possible to effectively suppress the immersion of slag that generally tends to occur in the gap, and to be resistant to corrosion. Is preferable because it becomes higher. Further, when an alumina refractory aggregate is further contained in addition to the alumina fine powder, when the alumina refractory aggregate is a powder material, the spinel is formed in the void formed by the coarse particle material or the fine particle material. Since a type | mold alumina-nickel oxide compound is produced | generated, corrosion resistance becomes higher and is preferable.
[0040]
When the amorphous refractory raw material according to the present invention contains alumina fine powder, the amorphous refractory raw material is usually 8 to 27% by weight of alumina fine powder, and nickel oxide powder or nickel powder is converted to NiO in an amount of 0.000. 7 to 18% by weight and 2 to 10% by weight of hydraulic binder, preferably 10 to 25% by weight of alumina fine powder, 1 to 15% by weight of NiO powder or nickel powder in terms of NiO, and hydraulic 2-5% by weight of binder is included. When the alumina fine powder and the nickel oxide powder or the like are contained in such a ratio, a spinel-type alumina-nickel oxide compound is easily generated and the corrosion resistance becomes higher, which is preferable.
[0041]
Further, when the amorphous refractory material according to the present invention contains an alumina fine powder and an alumina refractory aggregate, the amorphous refractory material usually contains 8 to 27% by weight of an alumina fine powder, and an alumina material. 48 to 80% by weight of refractory aggregate, 0.7 to 18% by weight of nickel oxide powder or nickel powder in terms of NiO, and 2 to 10% by weight of hydraulic binder, preferably 10 to 10% of alumina fine powder 25% by weight, 55-80% by weight of alumina refractory aggregate, 1-15% by weight of nickel oxide powder or nickel powder in terms of NiO, and 2-5% by weight of hydraulic binder. When the alumina fine powder, the alumina refractory aggregate, the nickel oxide powder and the like are contained in this ratio, a spinel type alumina-nickel oxide compound is easily generated and the corrosion resistance becomes higher, which is preferable.
[0042]
The amorphous refractory according to the present invention is obtained by adding water to the above-mentioned amorphous refractory raw material to obtain a kneaded product, and further firing the kneaded product. The amount of water added at this time is usually 4 to 7 parts by weight, preferably 5 to 6 parts by weight with respect to 100 parts by weight of the above-mentioned amorphous refractory raw material. If the amount of water added is less than 4 parts by weight, the fluidity of the kneaded product is low and the kneading tends to be difficult, which is not preferable. If the amount exceeds 7 parts by weight, the fluidity of the kneaded material becomes too high, and the fireproof aggregate This is not preferable because the ceramic fine powder is easily separated.
[0043]
In order to obtain a kneaded product, for example, a mixer is used. When the amorphous refractory according to the present invention is kneaded, the amorphous refractory raw material and water are kneaded at the above blending ratio and thus have excellent fluidity. Further, since the dispersant is blended in an amount within the above range, the fluidity of the kneaded product is particularly maintained long, and the usable time becomes long.
[0044]
The amorphous refractory according to the present invention can be obtained by appropriately shaping, drying and firing the kneaded product. For example, the kneaded product is put into a mold and molded to obtain a molded body having a predetermined shape, and then dried and fired to obtain an amorphous refractory. Examples of the forming method include vibration casting and thick coating on a mold at a construction site. Drying is performed at 80 to 120 ° C. for 17 to 24 hours, for example. Baking is performed at 1200-1500 degreeC for 5 to 24 hours, for example. In addition, the amorphous refractory according to the present invention is not provided with the above-described firing step for producing a refractory, and is applied to the inner wall of the melting furnace as it is in a dry body, and heat when using the melting furnace or the like. It can also be obtained by substantially baking. In addition, the organic fiber and dispersant blended as necessary are burned out after firing and are not present in the amorphous refractory.
[0045]
The amorphous refractory according to the present invention is excellent in corrosion resistance and heat resistance. In particular, amorphous refractory materials containing alumina fine powder, and amorphous refractories obtained from amorphous refractory raw materials containing alumina fine powder and containing alumina refractory aggregate, Since spinel-type alumina-nickel oxide compound is contained in the gaps between the aggregates, the corrosion resistance and heat resistance are more excellent. The amorphous refractory raw material according to the present invention and the amorphous refractory produced from the amorphous refractory raw material can be used for refractories for blast ladle and refractories for ash melting furnaces. .
[0046]
【Example】
EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.
[0047]
Example 1
31.0 parts by weight of a coarse particle of alumina refractory aggregate having a particle size of more than 1 mm and 3 mm or less, and 27.1 parts of a fine particle of alumina refractory aggregate having a particle size of more than 0.15 mm and 1 mm or less 10.4 parts by weight of an alumina refractory aggregate powder material having a particle size of more than 50 μm and not more than 0.15 mm, 10.0 parts by weight of nickel oxide powder having an average particle size of 1 μm, and alumina having an average particle size of 2 μm 100.0 parts by weight in total of 16.0 parts by weight of ultrafine powder, 1.5 parts by weight of silica ultrafine powder having an average particle diameter of 0.6 μm, and 4.0 parts by weight of hydraulic alumina having an average particle diameter of 10 μm 0.08 part by weight of fiber, 0.1 part by weight of a dispersant and 6.0 part by weight of water were added, and the mixture was kneaded with a mixer for 6 minutes. The fluidity of the obtained kneaded material was evaluated as the vibration flow value shown below. The results of the blending amount and vibration flow value are shown in Table 1. In Table 1, the amount is expressed in parts by weight.
Next, the kneaded material was cast and molded, dried at 105 ° C. for 24 hours, and further fired at 1400 ° C. for 5 hours to obtain an amorphous refractory. The corrosion resistance of the obtained amorphous refractory was evaluated as an erosion index shown below. The results are shown in Table 1.
[0048]
[Measurement method of vibration flow value]
First, a flow cone defined in JIS R 5201: 92 was placed on a vibration table so that the tip of the cone faced upward, and the kneaded material was filled into the flow cone while appropriately vibrating. Next, the cone was slowly removed so as not to break the shape of the filled kneaded material, and then 60 Hz vibration was quickly applied for 30 seconds. After the end of vibration, two points of the maximum value of the diameter of the bottom of the kneaded material that collapsed and spread and the diameter of the part perpendicular to the maximum value part were measured, and the average value of the two parts was the vibration flow value (mm) It was. As the vibration flow value, the larger the value, the better the fluidity.
[0049]
[Measurement method of erosion index]
First, a test sample A composed of an irregular refractory material having an isosceles trapezoidal column shape (
After 8 hours, the specimen B is separated for each sample A, and the longitudinal direction of the lower bottom rectangular surface from the longitudinal center line ab of the upper bottom rectangular surface where the slag contacts the sample A as shown in FIG. It cut | disconnected so that the substantially rectangular cut surface abdc might appear to the centerline cd. Next, as shown in FIG. 4, the erosion area of the erosion part F by the slag of the cut surface abdc was measured, and the erosion rate was calculated by the following formula (1).
Erosion rate (%) = (Area of erosion part of cross section / total area of cross section) × 100 (1)
Next, the erosion index was calculated by the following formula (2) from the erosion rate of the obtained target sample and the erosion rate of the standard sample (amorphous refractory fired using conventional alumina cement as a binder). Table 1 shows the composition and physical properties of the standard sample.
[0050]
[Table 1]
Comparative Example 1
A kneaded material and an amorphous refractory were obtained in the same manner as in Example 1 except that 4.0 parts by weight of alumina cement was used instead of 4.0 parts by weight of hydraulic alumina. evaluated. Table 1 shows the blending amounts of raw materials, vibration flow values, and erosion index results.
[0052]
Comparative Example 2
A kneaded material and an amorphous refractory were obtained in the same manner as in Example 1 except that nickel oxide was not blended and the powder material of alumina-based refractory aggregate was changed to 20.4 parts by weight. And evaluated. Table 1 shows the blending amounts of raw materials, vibration flow values, and erosion index results.
[0053]
Examples 2 to 4, Comparative Examples 3 and 4
As shown in Table 2, a kneaded material and an amorphous refractory were obtained in the same manner as in Example 1 except that the blending amount of nickel oxide powder and the like was changed, and these were evaluated in the same manner as in Example 1. Table 2 shows the blending amounts of raw materials, vibration flow values, and erosion index results. In Comparative Example 4, the erosion test was impossible because of cracks in the molded body.
[0054]
[Table 2]
Reference example 1
31.0 parts by weight of coarse particles of SiC (silicon carbide) refractory aggregate having a particle size of more than 1 mm and 3 mm or less, fine particles of SiC refractory aggregate having a particle size of more than 0.15 mm and 1 mm or less 28.4 parts by weight of material, 18.4 parts by weight of powder material of SiC-based refractory aggregate having a particle size of more than 50 μm and not more than 0.15 mm, 2.0 parts by weight of nickel oxide powder having an average particle size of 1 μm, average particle A total of 16.0 parts by weight of alumina ultrafine powder having a diameter of 2 μm, 1.5 parts by weight of silica ultrafine powder having an average particle diameter of 0.6 μm, and 4.0 parts by weight of hydraulic alumina having an average particle diameter of 10 μm100.00.08 part by weight of organic fiber, 0.1 part by weight of a dispersant and 6.0 part by weight of water were added to parts by weight, and the mixture was kneaded for 6 minutes with a mixer. The fluidity of the obtained kneaded material was evaluated as a vibration flow value in the same manner as in Example 1. The results of the blending amount and vibration flow value are shown in Table 3. In Table 3, the amount is expressed in parts by weight. Next, an amorphous refractory was obtained from the kneaded material in the same manner as in Example 1. The corrosion resistance of the obtained amorphous refractory was evaluated as an erosion index in the same manner as in Example 1. The results are shown in Table 3.
[0056]
[Table 3]
Comparative Example 5
Aside from using 4.0 parts by weight of alumina cement instead of 4.0 parts by weight of hydraulic alumina,Reference example 1The kneaded material and the amorphous refractory were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 3 shows the blending amounts of raw materials, vibration flow values, and erosion index results.
[0058]
Comparative Example 6
Except for not containing nickel oxide and 20.4 parts by weight of powder material of SiC fireproof aggregateReference example 1The kneaded material and the amorphous refractory were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 3 shows the blending amounts of raw materials, vibration flow values, and erosion index results.
[0059]
Reference example 2
As shown in Table 3, except that the blending amount of nickel oxide powder and the like was changed,Reference example 1The kneaded material and the amorphous refractory were obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. Table 3 shows the blending amounts of raw materials, vibration flow values, and erosion index results.
[0060]
Example5-7Comparative Example 7
As shown in Table 4, a kneaded material and an amorphous refractory were obtained in the same manner as in Example 1 except that the blending amount of nickel oxide powder and the like was changed, and these were evaluated in the same manner as in Example 1. Table 4 and FIG. 5 show the results of blending amounts of raw materials, vibration flow values, erosion index, and average pore diameter. The average pore diameter was measured with a mercury porosimeter after cutting the obtained amorphous refractory to produce small pieces.
[0061]
[Table 4]
From Table 1, Example 1 of the alumina-based amorphous refractory material has a smaller erosion index and excellent corrosion resistance than either Comparative Example 1 using alumina cement or Comparative Example 2 in which no nickel oxide powder was blended. From Table 2, the balance between fluidity and corrosion resistance is excellent when the content of nickel oxide is at least 0.7 to 18% by weight..
[0063]
From Table 4 and FIG. 5, examples of alumina-based amorphous refractory material5-7As compared with Comparative Example 7, it can be seen that the average pore diameter and the erosion index are small and the corrosion resistance is excellent, and the balance between fluidity and corrosion resistance is excellent. Moreover, from Table 4 and FIG. 5, it turns out that an average pore diameter becomes small by adding a nickel oxide fine powder with respect to an alumina fireproof aggregate and an alumina fine powder, and corrosion resistance becomes high in connection with it. The relationship between the average pore diameter and the corrosion resistance in FIG. 5 is that the generated spinel-type alumina-nickel oxide compound fills the voids in the resulting alumina-based amorphous refractory, thereby suppressing the immersion of slag. It can be said that this suggests.
[0064]
【The invention's effect】
When a predetermined kneaded water is added to the amorphous refractory raw material according to the present invention, a kneaded product excellent in fluidity can be obtained at low cost, and the amorphous refractory obtained by firing the kneaded product is excellent in corrosion resistance. . That is, an amorphous refractory having excellent corrosion resistance can be manufactured at a low cost with excellent workability.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a sample shape in an erosion test.
FIG. 2 is a schematic diagram showing an erosion test.
FIG. 3 is a schematic diagram showing a method for evaluating an erosion rate.
FIG. 4 is a schematic diagram showing a method for evaluating an erosion rate.
FIG. 5 is a graph showing the relationship between the amount of nickel oxide added, the erosion index, and the average pore diameter.
[Explanation of symbols]
A Sample of irregular refractory
B Hexagonal column specimen
C Rotating device
D recess
E slug
F erosion part
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| JP2000173540A JP3741595B2 (en) | 1999-07-13 | 2000-06-09 | Unshaped refractory raw material and unshaped refractory |
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| JP19869599 | 1999-07-13 | ||
| JP11-198695 | 1999-07-13 | ||
| JP2000173540A JP3741595B2 (en) | 1999-07-13 | 2000-06-09 | Unshaped refractory raw material and unshaped refractory |
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| Publication Number | Publication Date |
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| JP2001080969A JP2001080969A (en) | 2001-03-27 |
| JP3741595B2 true JP3741595B2 (en) | 2006-02-01 |
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Cited By (1)
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| CN103553671A (en) * | 2013-10-29 | 2014-02-05 | 宁夏天纵泓光余热发电技术有限公司 | High-strength pouring material for pouring basket of continuous caster |
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| JP4555520B2 (en) * | 2001-09-14 | 2010-10-06 | 新日本製鐵株式会社 | Method for manufacturing amorphous refractories with excellent corrosion resistance |
| CN104311056B (en) * | 2014-10-08 | 2016-08-24 | 宁夏天纵泓光余热发电技术有限公司 | Mullite fiber castable refractory |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103553671A (en) * | 2013-10-29 | 2014-02-05 | 宁夏天纵泓光余热发电技术有限公司 | High-strength pouring material for pouring basket of continuous caster |
| CN103553671B (en) * | 2013-10-29 | 2014-10-22 | 宁夏天纵泓光余热发电技术有限公司 | High-strength pouring material for pouring basket of continuous caster |
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