JP4005650B2 - Coating agent for hot silicate alkali construction and hot construction method using the same - Google Patents
Coating agent for hot silicate alkali construction and hot construction method using the same Download PDFInfo
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- JP4005650B2 JP4005650B2 JP13888396A JP13888396A JP4005650B2 JP 4005650 B2 JP4005650 B2 JP 4005650B2 JP 13888396 A JP13888396 A JP 13888396A JP 13888396 A JP13888396 A JP 13888396A JP 4005650 B2 JP4005650 B2 JP 4005650B2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5076—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with masses bonded by inorganic cements
- C04B41/5089—Silica sols, alkyl, ammonium or alkali metal silicate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00482—Coating or impregnation materials
- C04B2111/00551—Refractory coatings, e.g. for tamping
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- Materials Engineering (AREA)
- Structural Engineering (AREA)
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- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、高温炉の壁面である煉瓦、不定形耐火物、目地などの部位に熱間で施工すると、表面に釉層を形成する珪酸アルカリ熱間施工用塗布剤および熱間施工方法に関する。
【０００２】
【従来の技術】
高温炉は工業的な種々な用途に使用されているが、使用過程において炉から生成する反応物あるいは塵埃などが付着し、スケールが成長したり、あるいは長時間の使用で損傷したりするなどのトラブルが発生する。このため炉の耐火物の表面をより緻密な層でコーティングしたり、あるいは損傷部に耐火物材料を埋め込み補修することが必要となる。
【０００３】
小型炉では、このような場合、炉を止めてしかるべき措置をすることが容易であるが、大型炉の場合は長時間にわたり連続運転をすることが多く、炉を冷却しないで熱間で措置することが必要なケースが多い。
【０００４】
炉の耐火物の表面を熱間でコーティングする方法としては、不定形耐火物の吹き付け、あるいはプラズマまたはアーク溶射などの方法がある。
【０００５】
前者の方法は、比較的安価な方法であるが、緻密なコーティング層を形成するのが難しいこと、またコーティング層の強度があまりなく剥離しやすいことなどの欠点を有する。
【０００６】
後者の方法は、比較的強度の高い膜が形成可能であるが、施工コストが高価で、しかも経済性に難点があるという欠点を有する。
【０００７】
特開昭６３−２３６７８３には、釉薬と煉瓦を同時焼成し釉層が形成されたコークス炉用耐火物煉瓦を製造する方法が開示されている。この釉層を形成した煉瓦を用いる方法は、密着性が良好で操業中脱落することもない。また釉層皮膜中の気孔も殆どないため、カーボンが浸透することもなく非常に効果的な方法である。しかしながら、コークス炉または炉蓋などを新たに製作する場合にこの方法が適用可能であるが、炉を操業しながら熱間で、炉の耐火物表面に釉層を形成することは不可能である。すなわち、釉層を形成するためには釉の溶融温度以上の温度にしなければならず、この温度が操業温度より高い場合には通常、炉の操業温度では溶融しないため釉層が形成されない。逆に、釉の溶融温度が操業温度より低い場合には、操業温度では溶融状態であるため、皮膜としての役割を果たさない。
【０００８】
本発明者らはこの点に鑑み、熱間施工直後は、釉の溶融温度が低く操業温度で容易に釉層を形成し、その後はその釉層中の蒸気圧の高い成分が蒸発し、次第に溶融温度が上昇し、操業温度でも充分使用に耐える熱間施工用塗布剤を開発した（国際公開ＷＯ９５／３１４１８）。
【０００９】
この熱間施工用塗布剤は、熱間施工時に瞬間的に発泡し、綿菓子状のコーティング層を形成する。これは機械的に弱いため綿菓子状のものが溶融し、ガラス状となるまでの数十秒の間に炉の対流あるいは振動などにより剥離、脱落などが生じやすく、非常に歩留まりが悪くなる欠点がある。
【００１０】
また、脱落した塗布物が炉底に落下、付着し、堆積物となりトラブルの原因となる。このため、炉の補修などの目的で厚塗りが必要な場合には、歩留まりが悪いため数回に分けて熱間施工塗布しなければならず、塗布剤の材料費、施工労務費の面でコストアップにつながっていた。
【００１１】
【発明が解決しようとする課題】
本発明は、前記の問題点に鑑みて成されたものであり、熱間施工時に発泡が少なく、歩留まりがよい厚塗り可能な熱間施工用塗布剤を提供することを目的とする。
【００１２】
また、できるだけ厚塗りするため塗布剤溶液の固形分濃度を過度に上げると必然的に粘度が上昇し、半固形状態となり熱間施工塗布時のスプレー性が不良となり施工できないという問題が生ずる。したがって、本発明のもう一つの目的は、熱間施工用塗布剤の粘度をスプレー可能な程度以下に維持し、かつ固形分濃度を上げることにある。
【００１３】
さらに本発明のもう一つの目的は、不定形耐火物に対する熱間での吹き付け装置および方法に応用可能な熱間施工用塗布剤を提供することにある。
【００１４】
【課題を解決するための手段】
本発明によれば、釉層を形成する熱間施工直後の組成として、酸化物基準でＲ２Ｏ（ＲはＮａ，ＫまたはＬｉの１種以上を表す）を１０〜４０重量％と、残部にＳｉＯ２を含み、釉の溶融温度が１０００℃以下である珪酸アルカリ熱間施工用塗布剤において、水溶液状態で珪酸アルカリを酸化物基準で３５〜５０重量％含み、かつ２０℃での粘度が１００〜２０００ｃｐｓに調整されてなることを特徴とする珪酸アルカリ熱間施工用塗布剤が提供される。
また本発明によれば、釉層を形成する熱間施工直後の組成として、酸化物基準でＲ２Ｏ（ＲはＮａ，ＫまたはＬｉの１種以上を表す）を１０〜４０重量％と、Ｂ２Ｏ３を０．５〜２０重量％と、残部にＳｉＯ２を含み、釉の溶融温度が１０００℃以下である珪酸アルカリ熱間施工用塗布剤において、水溶液状態で珪酸アルカリおよびホウ素化合物を酸化物基準で３５〜５０重量％含み、かつ２０℃での粘度が１００〜２０００ｃｐｓに調整されてなることを特徴とする珪酸アルカリ熱間施工用塗布剤が提供される。
さらに本発明によれば、釉層を形成する熱間施工直後の組成として、酸化物基準でＲ２Ｏ（ＲはＮａ，ＫまたはＬｉの１種以上を表す）を１０〜４０重量％と、残部にＳｉＯ２を含み、釉の溶融温度が１０００℃以下である珪酸アルカリ熱間施工用塗布剤において、水とのスラリー状態で水に溶解した珪酸アルカリと、水に溶解しない固体状の粉末珪酸アルカリを合計で４０〜７０重量％含むように調整されてなることを特徴とする珪酸アルカリ熱間施工用塗布剤が提供される。
加えて本発明によれば、釉層を形成する熱間施工直後の組成として、酸化物基準でＲ２Ｏ（ＲはＮａ，ＫまたはＬｉの１種以上を表す）を１０〜４０重量％と、Ｂ２Ｏ３を０．５〜２０重量％と、残部にＳｉＯ２を含み、釉の溶融温度が１０００℃以下である珪酸アルカリ熱間施工用塗布剤において、水とのスラリー状態で水に溶解した珪酸アルカリおよびホウ素化合物と、水に溶解しない固体状の粉末珪酸アルカリおよびホウ素化合物とを合計で４０〜７０重量％含むように調整されてなることを特徴とする珪酸アルカリ熱間施工用塗布剤が提供される。
前記の珪酸アルカリ熱間施工用塗布剤において、好適には釉の溶融温度は９００℃以下である。
また好適には、前記塗布剤はコークス炉への塗布剤である。
さらに本発明によれば、前記珪酸アルカリ熱間施工用塗布剤を６００℃以上の炉の耐火物に熱間塗布することを特徴とする熱間施工方法も提供される。本発明は、特定の酸化物の組合せから成り、炉内壁面に施工すると炉の実炉温度付近あるいはそれ以下の温度で一旦、溶融し釉層を形成するが、施工後、釉の溶融温度が次第に上昇し釉層を堅持するような釉薬を形成するための珪酸アルカリを主成分とする熱間施工用塗布剤を要旨とするが、さらに塗布剤の固形分濃度が特定濃度以上であり、粘度が所定の粘度範囲であるので、熱間施工の際、歩留まりがよく厚膜施工可能な塗布剤である。
【００１５】
【発明の実施の形態】
以下本発明をさらに詳しく説明する。
【００１６】
本発明で使用される珪酸アルカリとしては、珪酸リチウム、珪酸カリウムまたは珪酸ナトリウムの一種以上であり、混合物の場合、これら珪酸塩の比率は必要とする釉の組成より決定され、その範囲内で水に対する溶解度、粘度などの点より適切な組合わせを選択する。
【００１７】
本発明の実施の第１形態によれば、熱間施工用塗布剤中の珪酸アルカリ（ホウ素化合物をさらに含んでもよい）の固形分濃度は酸化物基準で３５〜５０重量％であり、好ましくは３５〜４５重量％である。固形分濃度が前記範囲内にあると、塗布剤の炉への施工としてはスプレーによる方法が好ましく用いられる。
【００１８】
コークス炉などの操業温度１０００℃以上の炉壁に塗布剤（液）を熱間施工した場合、初期段階では急激に水が蒸発し、塗布液全体が発泡し、綿菓子状となる。これが数十秒の間に炉の熱で溶融しガラス状皮膜を形成するが、この綿菓子状の状態では塗布液の水分が多いほど密度が小さく、生成時の強度が弱く、その結果、わずかな機械的な力で脱落しやすい。特に３５％未満の固形分濃度のときにこの傾向が著しく、３５％を超えるとこの現象が急激に小さくなることを本発明者らは見い出し、本発明を完成した。
【００１９】
スプレーによる熱間施工は、湿式で行うため塗布液の流動性が必須条件であり、このためには粘度は３０００ｃｐｓ以下、好ましくは２０００ｃｐｓ以下であることが必要である。またスプレーの場合には、粘度が低すぎると液滴が広がりやすく施工ロスが多くなるため、１００ｃｐｓ以上であることが好ましい。
【００２０】
珪酸アルカリの水に対する溶解度には限界があり、また溶解度が増加するに従って粘度も上昇する。一般的に、アルカリ量の比率が高いと溶解度が高くなり、同一溶解度での粘度が低くなる。アルカリ成分（Ｒ2Ｏ）は熱間施工後、釉層が形成されると速やかに気散する必要があり、アルカリ成分の比率が高すぎると皮膜特性が劣化するので好ましくない。
【００２１】
すなわち、アルカリ成分の適量は、熱間施工後に形成される釉の溶融温度、皮膜特性の面から決まり溶解度調整、粘度調整のためにむやみに増やすことはできない。したがって、アルカリ成分の好ましい範囲は、熱間施工直後の釉層の組成として酸化物基準で１０〜４０重量％である。
【００２２】
本発明の珪酸アルカリ熱間施工用塗布剤がホウ素化合物を含むとき、熱間施工直後に形成される釉層の組成として酸化物基準でＢ2Ｏ3を０．５〜２０重量％を含有することが好ましい。
【００２３】
釉層の組成がＲ2Ｏ，Ｂ2Ｏ3に関して前記の範囲をはずれると、溶融温度が高くなるか、さらにコーティングしたとき、成膜性も劣るので好ましくない。なお、釉層の残部は通常ＳｉＯ2から成るが、さらに他の酸化物を含んでいてもよい。
【００２４】
このような酸化物の例として、ＭｏＯ3 等が挙げられる。したがって、本発明の熱間施工用塗布剤は、アルカリ成分、ホウ素化合物の他に、第３成分としてＭｏＯ3の前躯体すなわちＮａ2［Ｍｏ3Ｏ10］・７Ｈ2Ｏ、Ｎａ6［Ｍｏ7Ｏ24］・２２Ｈ2Ｏ等のモリブデン酸ナトリウムを含むことができる。
【００２５】
本発明の実施の第２形態によれば、珪酸アルカリ熱間施工用塗布剤が水に溶解した珪酸アルカリと、水に溶解しない固体状の粉末珪酸アルカリのスラリーとから成り、これらの固形分濃度が酸化物基準で４０〜７０重量％である。
【００２６】
さらに本発明の実施の第３形態によれば、珪酸アルカリ熱間施工用塗布剤が水に溶解した珪酸アルカリおよびホウ素化合物と、水に溶解しない珪酸アルカリおよびホウ素化合物のスラリーとから成り、これらの固形分濃度が酸化物基準で４０〜７０重量％である。
【００２７】
前記実施の第２および第３形態に従う熱間施工用塗布剤は、実施の第１形態に従うものよりも固形分濃度が比較的高く設定されている。このようなスラリー状の塗布剤は、珪酸アルカリの溶解が進み、粘度が上昇しない時間内に使用するか、または熱間吹き付け法に用いるのが特に好ましい。特に、後者の方法を適用するとスプレー施工するより高粘度の塗布剤が使用可能であり、実施の第２および第３形態に従う塗布剤は、前述のような粘度範囲（たとえば１００〜２０００ｃｐｓ）の制限を受けない。この場合、塗布剤の望ましい粘度は、使用する吹き付け装置に適合するように適宜調整できる。
【００２８】
このように塗布剤を熱間で炉の壁面に塗布するが、釉層を形成するには釉の溶融温度が炉の操業温度以下でなければならず、操業温度以上だと釉層が形成されない。操業温度は炉の種類によって異なるがコークス炉を例に取ると１０００℃〜１１００℃であり、本発明の珪酸アルカリ熱間施工用塗布剤が適用可能である。その他の炉も、本発明の塗布剤の溶融温度以上で操業されるものであれば適用可能である。
【００２９】
なお、前記実施の第２および第３形態に従う珪酸アルカリ熱間施工用塗布剤を使用することにより形成される釉層の組成も酸化物基準としてとると、前記実施の第１形態に従う珪酸アルカリ熱間施工用塗布剤から得られるものと実質的に同一の範囲にある。
【００３０】
本発明の珪酸アルカリ熱間施工用塗布剤の特徴は、炉内壁面に施工すると炉の操業温度付近あるいはそれ以下の温度で、一旦溶融し、施工された耐火物表面に均一、緻密なガラス質釉層の皮膜を形成するが、釉層は時間の経過とともに溶融温度が上昇し炉の操業温度で再び溶融しないので、堅固な皮膜が保持されることである。
【００３１】
本発明の珪酸アルカリ熱間施工用塗布剤によって形成される釉の溶融温度は、実炉温度以下で、コークス炉であれば炉内壁耐火物の周辺部を考慮して約１０００℃以下、好ましくは約９００℃以下に設定する必要がある。溶融温度を設定値以下になるように、組成物の成分比を適宜調整することも本発明の一態様である。具体的には、Ｌｉ2Ｏ，Ｎａ2Ｏ，Ｋ2Ｏ，Ｂ2Ｏ3の一種以上と、ＳｉＯ2を成分とする状態図（たとえば、F.C.Kracek，J.Am.Chem.Soc.，61,2871（1939）を参照）から溶融温度１０００℃以下、好ましくは９００℃以下の適当な領域で各成分の重量％を求め、所望の成分比を与えるよう、珪酸アルカリ、必要ならばさらにホウ素化合物を各々規定量混合し、本発明の珪酸アルカリ熱間施工用塗布剤を得ることができる。
【００３２】
本発明において、釉の溶融温度が施工後、上昇する理由は、塗布剤の成分の一部が時間とともに輝散または拡散するためと考えられる。この機構の詳細は、本発明を限定するものではないが、たとえばＲ2ＯがＳｉＯ2と共存すると、溶融温度（ＳｉＯ2 単独ならば１７２８℃）を著しく降下させる。これらアルカリ金属酸化物は拡散係数が大きくまた蒸気圧も比較的高いため、施工後、時間の経過とともに拡散、輝散し釉の組成がＳｉＯ2 膜に近づき、その結果溶融温度が上昇する。Ｂ2Ｏ3 も溶融温度降下に効果があり輝散しやすいので、Ｒ2Ｏと同様にＳｉＯ2と併用することができる。またＭｏＯ3も蒸気圧が高く容易に気散するので使用可能である。
【００３３】
本発明の珪酸アルカリ熱間施工用塗布剤の適用は、炉内損傷のある耐火物、あるいはカーボンの付着が予想される耐火物、特に炉内壁面（コークス炉、カーボン焼成炉）、焼付装置（炉蓋、ガス管）等に対して可能である。
【００３４】
以下本発明を実施例によりさらに詳しく説明するが、本発明はこれらによって制限されるものではない。実施例中「％」は全て重量％、「部」は重量部を表す。
【００３５】
実施例１３号水ガラス溶液（Ｎａ２Ｏ：８．７％、ＳｉＯ２：２７．８％、水：６３．５％）を１００部、珪酸リチウム溶液（Ｌｉ２Ｏ：２．２％、ＳｉＯ２：２０．０％、水：７７，８％）を４．４部よく混合し透明液とした。これをＡ液とする。
【００３６】
水９５９部に水酸化リチウム（ＬｉＯＨ）９６部を添加し、溶解した。次いでホウ酸粉末（Ｈ3ＢＯ3）３１８部を添加し、撹拌し完全に透明液にした。これをＢ液とする。
【００３７】
ナトリウムメチルシリコネート溶液（Ｎａ2Ｏ：１０．７％、ＣＨ3ＳｉＯ1.5：２０％（ＳｉＯ2 として１７．９％）、水：６９．３％）をＣ液とする。
【００３８】
Ａ液を６６．０部、Ｂ液を１．８部、Ｃ液を６．９部、水１３．７部をよく混合し透明液を得た。これをＤ液とする。なおＤ液の固形分濃度は、酸化物基準で２９．４％であり、粘度はＢ型粘度計で測定すると２０℃で２０ｃｐｓであった。
【００３９】
このＤ液１００部に対し、３号水ガラス粉末（Ｎａ2Ｏ：２０％、ＳｉＯ2：６１％、残部水）２６．０部を添加し完全に溶解するまで撹拌した。これをＥ液とする。
【００４０】
Ｅ液の固形分濃度は酸化物基準で４０％、粘度はＢ型粘度計で測定すると２０℃で２７０ｃｐｓであった。
【００４１】
ＳｉＯ2：３６％、Ａｌ2Ｏ3：５４％を含む市販のキャスタブル煉瓦を１００×１００×４０ｍｍに切断し、試験耐火物煉瓦とした。
【００４２】
この試験片を９００℃の炉に入れ加熱した。煉瓦の温度が９００℃に上がったのを確認した後、スプレーガンにて約５００ｇ／ｍ2相当のＥ液を煉瓦面に噴霧して、炉内の状態を観察した。塗布膜は少し泡立つが綿菓子状とはならず、約５ｍｍくらいの高さに泡立った後、約１分くらいで溶融し、均一なガラス状皮膜（釉層）を形成した。
【００４３】
また、熱間施工直後の釉の組成としては酸化物基準で、ＳｉＯ2：７４．８％、Ｎａ2Ｏ：２４．３％、ＬｉＯ2：０．３％、Ｂ2Ｏ3：０．５％であった。
【００４４】
実施例２〜５
実施例１のＤ液と３号水ガラス粉末の混合比率を下記の表１に示すように変化させ、実施例１と同様の試験方法で試験評価した。評価結果を表１に示す。
【００４５】
【表１】
なお、表中、良好とは綿菓子状のものが形成されず、１分以内でガラス皮膜を形成することをいう。
【００４７】
実施例６
実施例１に使用した３号水ガラス溶液（Ｎａ2Ｏ：８．７％、ＳｉＯ2：２７．８％、水：６３．５％）を１００部、３号水ガラス粉末を８部混合し完全溶解した。
【００４８】
固形分濃度は３９．８％であり、粘度は３２０ｃｐｓであった。実施例１と同様の試験を行った結果、ほぼ同様の良好な結果が得られた。
【００４９】
実施例７実施例１に使用したＤ液１００部に３号水ガラス粉末７５部を混合した。珪酸アルカリは完全溶解していなかった。固形分濃度は５１．５％で、混合直後の粘度は１８００ｃｐｓであった。
【００５０】
混合後、速やかに実施例１と同様の方法で試験した。発泡はさらに少なく、また３０秒以内でガラス状の良好な皮膜を形成した。
【００５１】
なお、この塗布液は時間とともに粘度が上昇し、２時間後には１００，０００ｃｐｓ以上であった。
【００５２】
実施例８
実施例１の組成の塗布剤をコークス炉において石炭投入口壁面の耐火物にスプレーにて熱間塗布した。壁温は約９００℃であった。スプレー後の発泡は少なく、１分以内に全体がガラス化したのが目視により観察できた。
【００５３】
比較例１
実施例１で用いたＤ液をＥ液と全く同様の方法で煉瓦にスプレー塗布し、観察した。この場合には発泡が大きく３〜４ｃｍの高さまで発泡し綿菓子状となった。このものは非常にふわふわした状態で機械的な力を加えると簡単に剥離した。
【００５４】
なお、このコーティング膜は約２分くらいで溶融し、ガラス状皮膜を形成した。
【００５５】
比較例２比較例１の組成の塗布剤（前記Ｄ液）をコークス炉において石炭投入口壁面の耐火物にスプレーにて熱間塗布した。壁温は約９００℃であった。スプレー後の全体が綿菓子状に発泡した。約２分以内に発泡体は溶融したがガラス化層が明確には目視により観察できなかった。同じことを３回繰返したところ実施例８と同程度のガラス化膜が観察できた。
【００５６】
【発明の効果】
本発明によれば、珪酸アルカリを主成分とする熱間施工用塗布剤をコークス炉等炉内壁面に施工することにより、緻密、耐久性、高性能の釉層を形成し、これによってカーボンの付着等を大幅に低減でき、炉の寿命延長が図られる。
【００５７】
また本発明によれば、高温炉の壁面である煉瓦、不定形耐火物、目地などの部位に熱間で塗布剤を施工することによって、緻密、耐久性、高性能の釉層を形成し、これによって耐火物表面への塵埃などの付着防止あるいは損傷部の補修が可能になり、前記と同様に炉の寿命延長が図られる。
【００５８】
さらに本発明によれば、熱間施工用塗布剤中の固形分濃度を上げ、粘度を調整しているので塗布剤のスプレー施工が可能であり、熱間施工時に発泡が少なく歩留まりもよく、コーティング膜の厚塗りができる。
【００５９】
加えて本発明によれば、熱間施工用塗布剤をスラリー状に調製できるので、塗布剤を熱間吹き付け施工できる。[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an alkali silicate hot-working coating agent and a hot-working method for forming a cocoon layer on a surface of a brick, an irregular refractory, a joint, or the like that is a wall surface of a high-temperature furnace.
[0002]
[Prior art]
High-temperature furnaces are used for various industrial applications, but in the process of use, reactants or dust generated from the furnace adheres, and scales grow or damage occurs after prolonged use. Trouble occurs. For this reason, it is necessary to coat the surface of the refractory of the furnace with a denser layer or to embed and repair the refractory material in the damaged part.
[0003]
In a small furnace, it is easy to stop the furnace and take appropriate measures in such a case, but in a large furnace, it is often operated continuously for a long time, and measures are taken hot without cooling the furnace. There are many cases that need to be done.
[0004]
As a method for hot coating the surface of the refractory in the furnace, there is a method such as spraying an amorphous refractory or plasma or arc spraying.
[0005]
The former method is a relatively inexpensive method, but has drawbacks that it is difficult to form a dense coating layer and that the coating layer is not strong enough to be peeled off.
[0006]
The latter method can form a film having a relatively high strength, but has a drawback that the construction cost is expensive and there is a problem in economical efficiency.
[0007]
Japanese Unexamined Patent Publication No. 63-236783 discloses a method for producing a refractory brick for a coke oven in which a glaze and a brick are simultaneously fired to form a straw layer. The method using the brick with the ridge layer has good adhesion and does not fall off during operation. In addition, since there are almost no pores in the soot coating, it is a very effective method without carbon permeation. However, this method can be applied when newly producing a coke oven or a furnace lid, but it is impossible to form a soot layer on the surface of the refractory of the furnace while operating the furnace. . That is, in order to form a soot layer, the temperature must be equal to or higher than the melting temperature of the soot, and when this temperature is higher than the operating temperature, the soot layer is not formed because it usually does not melt at the operating temperature of the furnace. Conversely, when the melting temperature of the soot is lower than the operating temperature, it does not play a role as a film because it is in a molten state at the operating temperature.
[0008]
In view of this point, the inventors of the present invention immediately after hot construction, the soot layer is easily formed at the operating temperature with a low melting temperature of the soot, and then the component having a high vapor pressure in the soot layer evaporates and gradually. An application agent for hot construction that has a melting temperature that is high enough to withstand use even at an operating temperature has been developed (International Publication WO95 / 31418).
[0009]
This hot-working coating agent foams instantaneously during hot-working to form a cotton candy-like coating layer. This is mechanically weak, so that the cotton candy-like material melts and tends to peel off or drop out due to convection or vibration in the furnace within several tens of seconds until it becomes glassy, resulting in a very poor yield. There is.
[0010]
Also, the fallen coating falls and adheres to the furnace bottom, and becomes a deposit, causing trouble. For this reason, when thick coating is required for the purpose of repairing the furnace, etc., the yield is poor, so it is necessary to apply hot work in several batches, and in terms of the material cost of the coating agent and construction labor cost It led to cost increase.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hot-applying coating agent that can be thickly coated with little foaming during hot construction and good yield.
[0012]
In addition, if the solid content concentration of the coating solution is excessively increased in order to coat as thickly as possible, the viscosity inevitably increases, resulting in a semi-solid state and poor sprayability at the time of hot application, resulting in a problem that the application cannot be performed. Accordingly, another object of the present invention is to maintain the viscosity of the coating agent for hot construction below a sprayable level and increase the solid content concentration.
[0013]
Still another object of the present invention is to provide a hot working coating agent applicable to a hot spraying apparatus and method for an irregular refractory.
[0014]
[Means for Solving the Problems]
According to the present invention, as a composition immediately after the hot work for forming the soot layer, 10 to 40% by weight of R 2 O (R represents one or more of Na, K or Li) on the basis of oxide, and the balance In the coating agent for hot silicate alkali construction containing SiO 2 and having a melting temperature of 1000 ° C. or lower, the alkali silicate is contained in an aqueous solution state in an amount of 35 to 50% by weight, and the viscosity at 20 ° C. A coating agent for hot construction of alkali silicate characterized by being adjusted to 100 to 2000 cps is provided.
According to the present invention, as the composition immediately after hot construction to form a glaze, R 2 O on an oxide basis (R is Na, represents one or more of K, or Li) and 10 to 40 wt%, In the coating agent for hot silicate alkali construction containing 0.5 to 20% by weight of B 2 O 3 and the balance of SiO 2 and the melting temperature of the soot being 1000 ° C. or less, the alkali silicate and boron compound are added in an aqueous solution state. There is provided an alkali silicate hot-working coating agent comprising 35 to 50% by weight based on an oxide and having a viscosity at 20 ° C. adjusted to 100 to 2000 cps .
According to the present invention is found, as a composition immediately after hot construction to form a glaze, (the R Na, represents one or more of K or Li) R 2 O on an oxide basis of 10-40 wt% And, in the coating agent for alkali silicate hot construction containing SiO 2 in the balance and the melting temperature of the soot is 1000 ° C. or less, the alkali silicate dissolved in water in a slurry state with water, and the solid state not dissolved in water A coating agent for hot construction of alkali silicate, characterized in that it is adjusted so as to contain 40 to 70% by weight of powdered alkali silicate in total.
In addition, according to the present invention, R 2 O (R represents one or more of Na, K, or Li) on the basis of oxide is 10 to 40% by weight as a composition immediately after the hot work for forming the soot layer. the B 2 O 3 and 0.5 to 20 wt%, wherein the SiO 2 to the remainder, the alkali silicate hot construction coating agent is the melting temperature of the glaze is 1000 ° C. or less, in water in a slurry state with water An alkali silicate hot construction coating characterized by being adjusted so as to contain a total of 40 to 70% by weight of a dissolved alkali silicate and boron compound and a solid powdered alkali silicate and boron compound not dissolved in water. An agent is provided.
In the above-mentioned coating agent for hot silicate alkali application, the melting temperature of the soot is preferably 900 ° C. or lower.
Also preferably, the coating agent is a coating agent for a coke oven.
Furthermore, according to the present invention, there is also provided a hot construction method characterized in that the above-mentioned alkali silicate hot construction coating agent is hot-applied to a furnace refractory at 600 ° C. or higher. The present invention consists of a combination of specific oxides, and when constructed on the furnace inner wall surface, it melts once at a temperature near or below the actual furnace temperature of the furnace and forms a soot layer. The main point is the coating agent for hot construction mainly composed of alkali silicate to form a glaze that gradually rises and maintains the glaze layer, but the solid content concentration of the coating agent is more than a specific concentration, and the viscosity Is a predetermined viscosity range, it is a coating agent with good yield and thick film construction during hot construction.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in more detail below.
[0016]
The alkali silicate used in the present invention is one or more of lithium silicate, potassium silicate or sodium silicate. In the case of a mixture, the ratio of these silicates is determined by the composition of the required soot, Select an appropriate combination from the viewpoint of solubility, viscosity, and the like.
[0017]
According to the first embodiment of the present invention, the solid content concentration of alkali silicate (which may further contain a boron compound) in the hot working coating agent is 35 to 50% by weight, preferably on the oxide basis. 35 to 45% by weight. When the solid content concentration is within the above range, a spray method is preferably used as a method for applying the coating agent to the furnace.
[0018]
When a coating agent (liquid) is hot-worked on a furnace wall having an operating temperature of 1000 ° C. or higher such as a coke oven, water is rapidly evaporated in the initial stage, and the entire coating liquid is foamed to form a cotton candy. This melts with the heat of the furnace in several tens of seconds to form a glassy film, but in this cotton candy-like state, the more water in the coating solution, the smaller the density and the weaker the strength at the time of production, and as a result It is easy to fall off with a strong mechanical force. In particular, the present inventors have found that this tendency is remarkable when the solid content concentration is less than 35%, and this phenomenon is rapidly reduced when the solid content exceeds 35%, and the present invention has been completed.
[0019]
Since the hot construction by spraying is performed in a wet manner, the fluidity of the coating solution is an essential condition. For this purpose, the viscosity needs to be 3000 cps or less, preferably 2000 cps or less. In the case of spraying, if the viscosity is too low, the droplets are likely to spread and the construction loss increases, so that it is preferably 100 cps or more.
[0020]
The solubility of alkali silicate in water is limited, and the viscosity increases as the solubility increases. In general, when the ratio of the alkali amount is high, the solubility increases and the viscosity at the same solubility decreases. The alkali component (R 2 O) needs to be quickly diffused when a soot layer is formed after hot construction, and if the ratio of the alkali component is too high, the film properties deteriorate, which is not preferable.
[0021]
That is, the appropriate amount of the alkali component is determined from the viewpoint of the melting temperature and film characteristics of the soot formed after the hot work, and cannot be increased unnecessarily for adjusting the solubility and adjusting the viscosity. Therefore, the preferable range of the alkali component is 10 to 40% by weight on the oxide basis as the composition of the soot layer immediately after the hot work.
[0022]
When the coating agent for alkali silicate hot construction of the present invention contains a boron compound, it contains 0.5 to 20% by weight of B 2 O 3 on the oxide basis as the composition of the soot layer formed immediately after the hot construction. It is preferable.
[0023]
If the composition of the soot layer deviates from the above range with respect to R 2 O and B 2 O 3 , the melting temperature becomes high, or further coating results in poor film formability. The remainder of the soot layer is usually made of SiO 2 but may further contain other oxides.
[0024]
Examples of such an oxide include MoO 3 and the like. Therefore, the coating agent for hot construction of the present invention has a precursor of MoO 3 as the third component, that is, Na 2 [Mo 3 O 10 ] · 7H 2 O, Na 6 [Mo 7 , in addition to the alkali component and the boron compound. It may contain sodium molybdate such as O 24 ] · 22H 2 O.
[0025]
According to the second embodiment of the present invention, the alkali silicate hot construction coating agent comprises an alkali silicate dissolved in water and a solid powdered alkali silicate slurry which does not dissolve in water. Is 40 to 70% by weight on the oxide basis.
[0026]
Furthermore, according to the third embodiment of the present invention, the alkali silicate hot construction coating agent comprises an alkali silicate and boron compound dissolved in water, and an alkali silicate and boron compound slurry not dissolved in water. The solid content concentration is 40 to 70% by weight based on the oxide.
[0027]
The coating material for hot construction according to the second and third embodiments is set to have a relatively high solid content concentration than that according to the first embodiment. Such a slurry-like coating agent is particularly preferably used within a time when the alkali silicate is dissolved and the viscosity does not increase, or is used in a hot spraying method. In particular, when the latter method is applied, a higher-viscosity coating agent than that applied by spraying can be used, and the coating agent according to the second and third embodiments is limited in the viscosity range (for example, 100 to 2000 cps) as described above. Not receive. In this case, the desired viscosity of the coating agent can be adjusted as appropriate to suit the spraying device used.
[0028]
In this way, the coating agent is applied hot to the wall surface of the furnace, but in order to form a soot layer, the melting temperature of the soot must be below the operating temperature of the furnace, and if it is above the operating temperature, the soot layer will not be formed. . Although the operating temperature varies depending on the type of furnace, taking a coke oven as an example, it is 1000 ° C. to 1100 ° C., and the coating agent for hot silicate alkali construction of the present invention is applicable. Other furnaces are applicable as long as they operate at a temperature equal to or higher than the melting temperature of the coating agent of the present invention.
[0029]
In addition, when the composition of the soot layer formed by using the coating agent for alkali silicate hot construction according to the second and third embodiments is also taken as an oxide standard, the alkali silicate heat according to the first embodiment is used. It is in substantially the same range as that obtained from the inter-applicable coating agent.
[0030]
The feature of the coating agent for hot silicate alkali construction of the present invention is that it is once melted at a temperature near or below the furnace operating temperature when applied on the inner wall surface of the furnace, and a uniform and dense glassy material on the surface of the applied refractory A soot layer is formed, but the soot layer has a melting temperature that rises with time and does not melt again at the furnace operating temperature, so that a firm film is maintained.
[0031]
The melting temperature of the soot formed by the alkali silicate hot working coating agent of the present invention is not higher than the actual furnace temperature, and in the case of a coke oven, it is about 1000 ° C. or less, preferably considering the periphery of the furnace wall refractory, It is necessary to set it to about 900 ° C. or less. It is also an embodiment of the present invention to appropriately adjust the component ratio of the composition so that the melting temperature becomes a set value or less. Specifically, a phase diagram (for example, FCKracek, J. Am. Chem. Soc., 61, which contains at least one of Li 2 O, Na 2 O, K 2 O, B 2 O 3 and SiO 2 as a component). 2871 (see 1939)), the weight percentage of each component is determined in an appropriate region at a melting temperature of 1000 ° C. or less, preferably 900 ° C. or less, and an alkali silicate and, if necessary, a boron compound are added to give a desired component ratio. Each specified amount can be mixed to obtain the alkali silicate hot construction coating agent of the present invention.
[0032]
In the present invention, the reason why the melting temperature of the soot rises after construction is considered to be because some of the components of the coating agent diffuse or diffuse with time. The details of this mechanism are not intended to limit the present invention. For example, when R 2 O coexists with SiO 2 , the melting temperature (1728 ° C. when SiO 2 alone is used) is significantly lowered. Since these alkali metal oxides have a large diffusion coefficient and a relatively high vapor pressure, the composition of the diffused and diffused soot approaches the SiO 2 film with the passage of time after construction, and as a result, the melting temperature rises. B 2 O 3 is also effective in lowering the melting temperature and easily shines, so it can be used in combination with SiO 2 in the same way as R 2 O. MoO 3 can also be used because it has a high vapor pressure and easily diffuses.
[0033]
Application of the coating agent for hot silicate alkali construction of the present invention can be applied to a refractory having damage in the furnace, or a refractory to which carbon is expected to adhere, particularly a furnace inner wall surface (coke furnace, carbon firing furnace), baking apparatus ( This is possible for furnace lids, gas pipes, etc.
[0034]
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, “%” represents “% by weight” and “parts” represents parts by weight.
[0035]
Example 13 100 parts of water glass solution (Na 2 O: 8.7%, SiO 2 : 27.8%, water: 63.5%), lithium silicate solution (Li 2 O: 2.2%, SiO 2 2 : 20.0%, water: 77,8%) was mixed well with 4.4 parts to obtain a transparent liquid. This is A liquid.
[0036]
96 parts of lithium hydroxide (LiOH) was added to 959 parts of water and dissolved. Next, 318 parts of boric acid powder (H 3 BO 3 ) was added and stirred to make it completely transparent. This is B liquid.
[0037]
A sodium methyl siliconate solution (Na 2 O: 10.7%, CH 3 SiO 1.5 : 20% (17.9% as SiO 2 ), water: 69.3%) is used as solution C.
[0038]
66.0 parts of Liquid A, 1.8 parts of Liquid B, 6.9 parts of Liquid C, and 13.7 parts of water were mixed well to obtain a transparent liquid. This is D liquid. The solid content concentration of the liquid D was 29.4% on the oxide basis, and the viscosity was 20 cps at 20 ° C. as measured with a B-type viscometer.
[0039]
To 100 parts of this D solution, 26.0 parts of No. 3 water glass powder (Na 2 O: 20%, SiO 2 : 61%, balance water) was added and stirred until completely dissolved. This is E liquid.
[0040]
The solid content concentration of liquid E was 40% on the oxide basis, and the viscosity was 270 cps at 20 ° C. as measured with a B-type viscometer.
[0041]
A commercially available castable brick containing SiO 2 : 36% and Al 2 O 3 : 54% was cut into 100 × 100 × 40 mm to obtain a test refractory brick.
[0042]
The test piece was placed in a 900 ° C. furnace and heated. After confirming that the temperature of the brick was raised to 900 ° C., an E liquid equivalent to about 500 g / m 2 was sprayed on the brick surface with a spray gun, and the state in the furnace was observed. Although the coating film foamed a little, it did not become a cotton candy shape. After foaming to a height of about 5 mm, the coating film melted in about 1 minute to form a uniform glassy film (saddle layer).
[0043]
Further, the composition of the soot immediately after the hot work is based on oxides, SiO 2 : 74.8%, Na 2 O: 24.3%, LiO 2 : 0.3%, B 2 O 3 : 0.5 %Met.
[0044]
Examples 2-5
The mixing ratio of the D liquid of Example 1 and No. 3 water glass powder was changed as shown in Table 1 below, and the test evaluation was performed by the same test method as in Example 1. The evaluation results are shown in Table 1.
[0045]
[Table 1]
In the table, “good” means that a cotton candy-like product is not formed and a glass film is formed within 1 minute.
[0047]
Example 6
100 parts of No. 3 water glass solution (Na 2 O: 8.7%, SiO 2 : 27.8%, water: 63.5%) used in Example 1 was mixed with 8 parts of No. 3 water glass powder. It completely dissolved.
[0048]
The solid content concentration was 39.8% and the viscosity was 320 cps. As a result of conducting the same test as in Example 1, almost the same good results were obtained.
[0049]
Example 7 75 parts of No. 3 water glass powder was mixed with 100 parts of Liquid D used in Example 1. The alkali silicate was not completely dissolved. The solid content concentration was 51.5%, and the viscosity immediately after mixing was 1800 cps.
[0050]
After mixing, the test was conducted immediately in the same manner as in Example 1. Foaming was even less and a good glassy film was formed within 30 seconds.
[0051]
This coating solution increased in viscosity with time, and after 2 hours was 100,000 cps or more.
[0052]
Example 8
The coating agent having the composition of Example 1 was hot-applied by spraying to the refractory on the wall surface of the coal inlet in a coke oven. The wall temperature was about 900 ° C. There was little foaming after spraying, and it was visually observed that the whole was vitrified within 1 minute.
[0053]
Comparative Example 1
The D solution used in Example 1 was spray-coated on the brick in the same manner as the E solution and observed. In this case, foaming was large and foamed to a height of 3 to 4 cm to form a cotton candy. This material peeled easily when mechanical force was applied in a very fluffy state.
[0054]
The coating film melted in about 2 minutes to form a glassy film.
[0055]
Comparative Example 2 A coating agent having the composition of Comparative Example 1 (said D solution) was hot-applied by spraying onto a refractory on the wall surface of the coal inlet in a coke oven. The wall temperature was about 900 ° C. Overall after the spray has been foamed in cotton-candy-shaped. Although the foam melted within about 2 minutes, the vitrified layer could not be clearly observed visually. When the same thing was repeated 3 times, the vitrification film comparable to Example 8 was observed.
[0056]
【The invention's effect】
According to the present invention, by applying a hot working coating agent mainly composed of alkali silicate on the inner wall surface of a furnace such as a coke oven, a dense, durable and high-performance soot layer is formed. Adhesion and the like can be greatly reduced, and the life of the furnace can be extended.
[0057]
In addition, according to the present invention, a dense, durable, high-performance cocoon layer is formed by applying the coating agent in a hot area to a brick, an indeterminate refractory, or a joint, which is the wall surface of a high-temperature furnace, This makes it possible to prevent dust from adhering to the surface of the refractory or to repair the damaged part, and to extend the life of the furnace as described above.
[0058]
Furthermore, according to the present invention, since the solid content concentration in the hot working application agent is increased and the viscosity is adjusted, the application agent can be applied by spraying. The film can be thickly coated.
[0059]
In addition, according to the present invention, since the hot-applying coating agent can be prepared in a slurry state, the coating agent can be hot-sprayed.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13888396A JP4005650B2 (en) | 1996-05-31 | 1996-05-31 | Coating agent for hot silicate alkali construction and hot construction method using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13888396A JP4005650B2 (en) | 1996-05-31 | 1996-05-31 | Coating agent for hot silicate alkali construction and hot construction method using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09328379A JPH09328379A (en) | 1997-12-22 |
| JP4005650B2 true JP4005650B2 (en) | 2007-11-07 |
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ID=15232351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13888396A Expired - Lifetime JP4005650B2 (en) | 1996-05-31 | 1996-05-31 | Coating agent for hot silicate alkali construction and hot construction method using the same |
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| Country | Link |
|---|---|
| JP (1) | JP4005650B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR19990069897A (en) * | 1998-02-13 | 1999-09-06 | 남창우 | Oxygen blocking silicate coating solution composition and method for producing film and sheet comprising same |
| US8481152B2 (en) * | 2008-08-14 | 2013-07-09 | General Electric Company | Refractory material with improved resistance to molten slag |
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1996
- 1996-05-31 JP JP13888396A patent/JP4005650B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09328379A (en) | 1997-12-22 |
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