JP4510218B2

JP4510218B2 - Quick setting agent for wet spray construction

Info

Publication number: JP4510218B2
Application number: JP2000096871A
Authority: JP
Inventors: 泰邦田中; 丈記吉富
Original assignee: Krosaki Harima Corp
Current assignee: Krosaki Harima Corp
Priority date: 2000-03-31
Filing date: 2000-03-31
Publication date: 2010-07-21
Anticipated expiration: 2020-03-31
Also published as: JP2001278674A

Description

【０００１】
【発明の属する技術分野】
本発明は、各種窯炉における不定形耐火材料の湿式吹付施工により形成された補修耐火物およびイニシャルライニングの速やかな強度発現を実現させるための急結剤に関する。
【０００２】
【従来の技術】
不定形耐火材料の湿式吹付施工は、枠なしで、かつ短時間に施工可能であり、施工体も乾式吹付施工に比べて緻密で、流し込み施工体並の品質を実現できることもあり、施工の省力化および低コスト化の観点から、各種窯炉において、炉の補修およびイニシャルライニングの施工方法として採用されている。その吹付け施工体の急結性を得るため消石灰スラリーを急結剤に使用することが、たとえば、特公昭５７−７３５０号公報、特公平２−２７３０８号公報および特表平１０−５０２５７４号公報に開示されている。
【０００３】
しかしながら、この湿式吹付施工には、吹付け材の性状の安定化、吹付け施工時における急結剤固体粒子の沈降防止、粘性抑制等が難しい等の問題があった。
この解決策として、本願出願人は、特願平１１−２９４５４７号出願の、消石灰スラリーからなる急結剤において、消石灰の粒度を規定し、さらに分散剤、さらには、分散安定化剤あるいは気泡剤を配合したものを開示した。しかしながら、強度発現速度において未だ不十分であるため、特に早期硬化を必要とする天井部等の上向きに吹き付ける施工では、十分な効果を発揮できるまでに至っていない。
【０００４】
【本発明が解決しようとする課題】
本発明は、吹付け材の性状の安定化を計り、圧送中の粘性を抑制し、施工中の急結剤固体粒子の沈降防止に優れ、かつ、吹き付けられた吹付け材の強度発現性に優れた不定形耐火材料の湿式吹付施工のための急結剤を提供する。
【０００５】
【課題を解決するための手段】
本発明の急結剤は、単にセメントの硬化促進をするだけのものではなく、吹付中、流動状態にある不定形耐火材料と急結剤との混合により、瞬時に流動性を消失せしめ、かつ、硬化して比較的強固な施工体とする機能を発揮するもので、粒子径０．３μｍ以上３０μｍ以下が８０％以上を占める粒度構成をもつ消石灰を５〜６０重量％と、残部が水からなる消石灰スラリー（以下、単に「スラリー」ともいう。）１００重量％に対し、リチウム塩をＬｉ_２Ｏに換算して０．０１〜１０重量％と、分散剤を０．１〜１０重量％外掛け添加してなる湿式吹付施工用の急結剤である。
【０００６】
本発明に使用する消石灰としては、一般の工業生産されているものから選択でき、良好な消石灰スラリーを得るために日本工業規格（ＪＩＳＲ９００１）の２号以上の成分、すなわちＣａＯ成分６５重量％以上のものが良く、強度発現効果を得るために、リチウム塩を添加する。
【０００７】
スラリーの消石灰濃度は、５〜６０重量％が良い。消石灰濃度が５重量％以下では急結性に劣り、材料との反応性が小さすぎるため、施工面で吹付け材が垂れるほか、スラリー中の水分が多くなると、施工体の気孔率が高くなり、強度などで所望の品質が得られない。また、６０重量％を越えると濃厚なスラリーとなりすぎ、粘性が高くなり、ホイップ状となる。そのため、圧送し難くなって急結剤注入用の急結剤ポンプが詰まったり、不定形耐火材料との混練が不均一となり良好な施工体とならない。
【０００８】
すなわち、消石灰が高濃度のスラリーでは、後述する消石灰の粒子径が０．３μｍより小さい粒子を２０％より多く含有する場合と同じく、低粘性化のためには、なお多量の分散剤が必要となり、吹付作業性、吹付施工体の品質などへ悪影響を及ぼすため、濃度は６０重量％以下にする。
【０００９】
リチウム塩は、不定形耐火材料の硬化を促進するもので、硬化時間を短縮できることは知られている。急結する機構については定かではないが、アルミナセメントより溶出されるアルミニウムイオンとリチウム塩から溶出したリチウムイオンが反応し、アルミン酸リチウムを生成することにより速硬性が向上すると考えられ、単なるセメントの硬化現象とは異なると考えられる。このような急結特性について、急結剤として石灰スラリーとリチウム塩とを組み合わせた場合に著しい急結性の向上が見られることの知見を得て、種々の検証実験から、その適正範囲を見いだした。
【００１０】
リチウム塩は、スラリー１００重量％に対してＬｉ_２Ｏ換算で、０．０１〜１０重量％の範囲で混合させることで急結剤として最大の効果を発現を有するもので、０．０１重量％より少ないと急結促進効果が見られない。１０重量％を越えると急結性は良好であるが、乾燥時に爆裂を引き起こす原因となる。
【００１１】
リチウム塩としては、水酸化リチウム、塩化リチウム、炭酸リチウム、弗化リチウム、乳酸リチウム、リン酸リチウム、クエン酸リチウム等多くのものが使用可能である。
【００１２】
本発明に使用する分散剤は、消石灰スラリーに対し圧送に可能な流動性を与える分散効果のある物質であるならば良い。たとえば分子量１５，０００以下のポリアクリル酸塩、芳香族スルホン酸塩、アルキルスルホン酸塩、リグニンスルホン酸塩、ポリカルボン酸塩、高分子ポリカルボン酸塩、有機りん酸塩、アルカリ金属炭酸塩、無機りん酸塩等である。これらは、１種類もしくは、２種類以上組み合わせて使用してよい。
【００１３】
分散剤を添加した粒子の分散によるスラリーの粘性調整は、圧送性および材料との十分な混合状態を得るため、２００ｍＰａ・ｓ未満が望ましく、スラリーに対して０．１〜１０重量％添加することで達成する。１０重量％より多いと急結性を阻害することとなり、０．１重量％より少ないと粘性低下に効果がない。
【００１４】
本発明では、消石灰の沈降をより抑え、分散性の良いスラリーを得るために、粒子径０．３μｍ以上３０μｍ以下が８０％以上を占める粒度構成をもつ消石灰を使用するが、具体的には、消石灰の全量中で０．３μｍ以上の粒子径のものが８０％以上であり、また、全量中で粒子径３０μｍ以下が８０％以上占め、かつ、前記３０μｍを越える粗粒域の粒子および０．３μｍ未満の微粒域の粒子が各々単独あるいは合量においても２０％以内の粒度構成になるよう粒度調整したものを使用することができる。
【００１５】
粒子径が３０μｍより大きい粒子を規定量より多く含む消石灰は、ボールミルなどで乾式もしくは湿式粉砕することにより粒度調整を行う。この規制する粒度範囲の消石灰を使用することによって、粒子の沈降速度は遅くなり施工中に水と粒子が分離することはなく、さらに、分散剤を使用することによって低粘性化でき、容易にポンプ圧送が可能であり、かつ急結性の良い消石灰スラリー急結剤が実現できる。
【００１６】
３０μｍより大きい粒子を２０％より多く含有する消石灰を使用した場合、粗い粒子の沈降は顕著となり、急結剤のタンク中でスラリー濃度に差が生じて一定濃度の急結剤を供給できなくなるほか、数時間の施工では、水と粒子の分離が進み、スラリー粘性が変化するため吐出量が不安定となり、ひいては圧送管内で詰まってしまい施工不能となる。また、０．３μｍより小さい粒子を２０％より多く含有すると、粒子の沈降速度は一段と遅くなり水と粒子の分離は問題ないものの、スラリーは高粘性となって圧送困難であり、低粘性化させるための分散剤も多量に必要とし、消石灰の反応性を鈍らせ、吹付時の付着不良や施工体の強度劣化を招く。
【００１７】
３０μｍを越える粗粒域と０．３μｍ未満の微粒域の粒子の合量においても２０％以内の粒度構成にすることは、中間粒域である３０〜０．３μｍの粒子量が少なくなることで、スラリーの粘性や沈降速度の調整がコントロールし難くなることを防ぐためである。
【００１８】
さらに、本発明の急結剤は、沈降抑制剤として分散安定化剤及び／又は気泡剤を０．０５〜５重量％の範囲内で１種以上単独であるいはこれらを組み合わせて外掛け添加することで、分離を抑制し、沈降を抑制した急結剤を得ることができる。なお、これらを組み合わせる比率は特定されず、任意に状況に応じて、組み合わせて使用できる。
【００１９】
分散安定化剤としては、溶媒である水と溶解して粘性を増加させ、消石灰粒子の沈降速度を小さくする効果をもつ無水珪酸、粘土などの無機増粘剤と、さらに消石灰粒子表面に吸着層を形成し、近接する粒子間で立体的に緩い架橋結合をスラリー全体に形成させ沈降を抑制する効果を合わせ持つ、たとえば、ＣＭＣ．ＰＶＡ、分子量２０，０００以上のポリアクリル酸塩などの水溶性高分子を使用できる。また、これらと同様な効果がある物質から１種又は２種以上を使用条件に合わせて選択して添加できる。これらの分散安定化剤の添加量は、スラリーに対し、０．０５〜５重量％が適正であり、０．０５重量％より少ないと増粘効果がなく、５重量％を越えると粘性が大きくなりすぎる。
【００２０】
気泡剤は、粒子表面へ気泡を付着させ、その気泡の浮力により沈降を抑制する効果がある。たとえばラウリル硫酸塩やカルボン酸系などの各種界面活性剤があり、これらと同様な効果をもつ物質から１種又は２種以上を選択して添加できる。その適正な添加量は、スラリーに対し０．０５〜５重量％であり、０．０５重量％より少ないと沈降抑制効果がなく５重量％を越えると気泡が多くなりすぎ、定量的な圧送は困難となる。
【００２１】
本発明の急結剤の吹付け材に対する添加量は、０．０１〜５重量％、より好ましくは０．１〜２重量％であり、１時間後の強度がより高いものになる。
【００２２】
本発明の急結剤は、アルミナセメントをボンドとする吹付け材に適応される。なお、本発明の急結剤は、装置や、熱間施工等の施工条件による拘束を受けることなく使用可能である。
【００２３】
【発明の実施形態】
本発明の実施の形態を表１および表２に示す実施例によって、比較例と対比して説明する。
【００２４】
各表に示す消石灰は、すべてＣａＯ量が７２．５重量％のものを使用し、水は水道水を使用した。
【００２５】
また、消石灰の沈降状況は、内径２５０ｍｍの透明なプラスチック容器に１００リットルの急結剤を入れ、上部に透明な水の層が形成され始める時間を沈降開始時間として測定した。
【００２６】
急結剤で別添加する分散剤としては、分子量１０，０００のポリアクリル酸ソーダ、沈降抑制を高めるための場合には分散安定化剤として分子量１００，０００のポリアクリル酸ソーダ、気泡剤にはカルボン酸系を用いた。
【００２７】
各試料はアルミナ質耐火原料、ボールクレー、蒸発シリカ、アルミナセメントをボンドとする湿式吹付け材料に水を６重量％添加し、急結剤は０．５重量％を急結剤タンクに流し込んで１時間静置後材料と共に吹付け施工し強度発現状況を測定した。
【００２８】
強度発現状態は、吹付け材を垂直に設置したシャモット質れんが表面に吹き付けたものから４０×４０×１６０の片を切り出した耐火物を、室温３０℃における１時間後に三点曲げによる養生曲げ強度を測定し、比較対象基準数値として１時間後の養生曲げ強度が３．０ｍＰａ以上を施工作業可能とした。
【００２９】
表１に示す実施例１〜１３は、リチウム塩を規定内で使用し強度発現効果を付加した消石灰スラリー系急結剤を示す。また、比較例１〜５は、実施例に対する分散剤、リチウム塩、沈降抑制剤の有無、および添加量等の過少による特性値の変化を測定した例を示す。
【００３０】
表１に示す急結剤は、消石灰の粒度を規制することなく平均的な粒度域である０．３〜３０μｍを主として使用し、リチウム塩を使用することで、従来よりも強度発現を速めることを主眼としたもので、半日以内に施工が完了可能な場合の使用にも適用できるものも含まれる。
【００３１】
【表１】

表１に示す参考例１〜１０は、リチウム塩として塩化リチウムを使用したもので、消石灰の量およびリチウム塩を規定内で変化させ特性を測定した。分散剤により粘性は２００ｍＰａ．ｓよりも低く、流動性には優れていることがわかる。沈降開始時間は分散剤の働きもあり何れも６時間以上を示し、特に沈降抑制剤を添加した参考例８〜１０は、１５時間以上沈降開始を延ばすことができ、作業の上でも時間的余裕をもって実施可能となった。
【００３２】
参考例のリチウム塩添加による急結剤を用いた吹付け耐火物の強度発現状態を測定した結果、参考例３〜１０は言うまでもなく、規定内ではあるが消石灰の濃度が５重量％と薄い参考例１、２においても、１時間後には３．０ｍＰａの基準値をクリアーし、その強度発現性の効果が得られ早期施工体形成が必要とされる箇所への作業も可能となった。
【００３３】
参考例１１〜１３は、参考例１０までのリチウム塩とは、異なるリチウム塩に置き換えて実施した例であり、何れも１時間後にはすでに基準値以上の養生曲げ強度を示した。
【００３４】
比較例１は、消石灰のみを規定範囲内で使用した例であるが、分散剤の添加がなく粘性が高すぎるため作業性が悪く、沈降抑制剤添加がなく３時間程度で沈降が始まり可使時間に問題がある。施工された耐火物も１時間後の曲げ強度が１．５ｍＰａと小さく希望される施工体は得られなかった。
【００３５】
比較例２は、比較例１と同様に消石灰のみが規定範囲内であり、分散剤、沈降抑制剤添加がないため粘性が高すぎるため作業性が悪く、３時間程度で沈降が始まり可使時間に問題がある。また、リチウム塩を添加したが消石灰に対するリチウム塩の使用比率が多すぎるため強度発現は早かったが爆裂により亀裂が発生して、１時間後の養生曲げ強度は基準値を越えることができず強度は劣化を示した。
【００３６】
比較例３は、消石灰が６０重量％を越えるため濃厚なスラリーとなりすぎ、分散剤の効果が得られず、沈降抑制剤を規定最大限に添加することで沈降開始時間は１４時間後と良好であったが、粘性が高く、圧送し難くなって急結剤注入用の急結剤ポンプが詰まり、また、不定形耐火材料との混線が不均一となって、リチウム塩の添加効果もなく、養生曲げ強度が１時間後では１．３ｍＰａを示し、その後爆裂により亀裂が発生し強度が劣化した。
【００３７】
比較例４は、消石灰が３重量％と少量であり、分散剤の添加作用で粘度は１０ｍＰａ・ｓであったが、沈降抑制剤を添加しても、沈降抑制作用は働かず、２０分で沈降を開始した。また、消石灰が少量のためリチウム塩の添加効果もほとんどなく、早期強度発現による養生曲げ強度の向上には至らなかった。
【００３８】
比較例５は、規定値内の消石灰３０重量％に分散剤を１．０重量％添加した例で、粘度、沈降開始時間等は何れも良好であるが、リチウム塩の添加がないため早期強度発現による施工体を得ようとする本発明の１時間後の養生曲げ強度３．０ｍＰａの目標に対し、１時間後の養生曲げ強度は２．２ｍＰａであり遠く及ばなかった。
【００３９】
表２に示す例は、長時間にわたり施工を行う場合にも適用できるように、リチウム塩に加え消石灰の粒度構成を規制して沈降速度を調整した実施例１〜１２と、それに対する比較例６〜１３を示すもので、分散剤、沈降抑制剤の有無、および添加量の過少および、粒度構成の変化による特性を測定した消石灰スラリー系急結剤を示す。
【００４０】
表２における消石灰の粒度はレーザー解析法により測定した。
【００４１】
【表２】

実施例１〜６はリチウム塩を消石灰の粒度構成に合わせて変化させた例であり、実施例１は、消石灰の使用量が５重量％と規定量内ではあるが少なく分散剤による粘性は低い。粒度構成は３０μｍを越えるものが０．３μｍ未満の粒子より多いため沈降開始は１２時間後と他の実施例より早いが、十分な可使時間を有しており、養生曲げ強度もリチウム塩により急結後、１時間後の養生曲げ強度において目的の数値３．０ｍＰａを越えて４．９ｍＰａを示した。
【００４２】
実施例２、３、４は、リチウム塩の添加量の変化で強度発現状態を見た。リチウム塩が多い実施例３は、９．５ｍＰａとすでに１時間後の養生曲げ強度において実施例２、４よりも高い強度の向上が見られた。
【００４３】
実施例５、６は、多量の消石灰を含有し０．３μｍ未満の粒子の量を多く使用した例で、沈降開始時間は２２時間後まで延ばすことが可能となった。粘性を下げるため分散剤を３．０重量％とした。また、実施例６はリチウム塩の量を増やすことで養生曲げ強度が実施例５より優れていた。
【００４４】
実施例７、８、９は塩化リチウム以外のリチウム塩を使用した例で、何れも沈降開始時間は１８時間後であり、養生曲げ強度も１時間後には基準の３．０ｍＰａを十分に越えた状態になっていた。
【００４５】
実施例１０〜１２は、沈降抑制剤の添加例で、実施例１０は分散安定化剤、実施例１１は気泡剤を、実施例１２は分散安定化剤と気泡剤の両方を添加したことで、沈降開始時間は何れも２４時間以上となり養生曲強度も十分であった。
【００４６】
比較例６、７は、消石灰の粒度構成で０．３μｍ未満を限度近く、また、３０μｍを越える粒子を規定量以上にし、両者の合量が２０％を越えた例である。リチウム塩の量を規定内で使用したため、何れもその強度発現効果は得られた。
【００４７】
しかし、比較例６では分散剤を１０重量％、さらに分散安定化剤も規定内の５重量％としたが、消石灰の３０μｍを越えるものを多く添加したことで粒度構成のバランスが保てないため、粘性は４００ｍＰａ・ｓと下がらず、また、沈降抑制効果も得られず、安定した吹付け作業ができない。
【００４８】
比較例７は、沈降抑制剤としての分散安定化剤、気泡剤の過剰添加により粘性が規定値まで低下せず、分散剤過多が影響して急結性が劣り、比較例６より強度発現低下の影響が見られた。さらに、消石灰粒度で３０μｍを越える量が多すぎ、沈降開始が４０分後と可使時間が短いため安定した吹付け作業はできない。
【００４９】
比較例８は消石灰の量を規定内最低の５重量％とし、その粒度構成で０．３μｍ未満を２８％と多量にすることで１８％を占める３０μｍを越える粒子との沈降のバランスをとって沈降開始の時間は８時間後となったが、それらの合量が２０％を越える中で０．３μｍ未満の粒子が多すぎて分散剤による粘性低下はならず、リチウム塩の添加は規定内ではあるが２．０％程度では消石灰の量自体が少ないため強度発現効果も得られなかった。
【００５０】
比較例９は、比較例８と同様に消石灰の０．３μｍ未満の粒子を２６％と規定以上に使用した例で、消石灰量は３０重量％と十分で、リチウム塩による強度発現効果も良い。しかし、過剰な微粒子は沈降開始時間は延長には役に立ったが分散剤による粘性を低下を成し得ず、吹付け作業に支障をきたした。
【００５１】
比較例１０は、消石灰の量を７０重量％と規定以上に使用した例である。過剰な消石灰は粘性を低下させきれず吹付け作業は完遂できなかった。
【００５２】
比較例１１は、消石灰の量自体が４重量％と規定値より少量であり、リチウム塩添加による強度発現効果を得るには足らなかった。
【００５３】
比較例１２、１３は分散剤を添加しなかったため、何れも粘性が高く、安定した吹付け作業ができなかった。
【００５４】
図１は、表１に示す参考例９と比較例５の養生曲げ強度を比較したものである。耐火物として、アルミナセメントボンドの湿式不定形耐火材料を用いた。
【００５５】
吹付試験は不定形耐火材料をミキサーで混練し、アレンタウン（Ａｌｌｅｎｔｏｗｎ）製ＡＰ−１０スイング弁ポンプを用いて、内径０．０５１ｍ（２インチ）、長さ３０．４８ｍ（１００ｆｔ）のヘビーデューティーホース内を圧送し、さらに先端に接続した吹付ノズル部において、０．５５ｍＰａ（８０ｐｓｉ）、８．５ｍ^３／分（３００ｃｆｔ）の圧縮空気を急結剤とともに添加し、垂直に設置したシャモット質れんが表面（１ｍ^２）に１５０ｍｍ厚さを吹き付ける方法で実施した。
【００５６】
同図に示す通り、参考例９の場合には、１時間後にはすでに８．５ｍＰａの強度を示し、およそ２．５時間後には最高の強度発現状態となり作業効率向上を目指すに十分な強度を示している。これに対し、比較例５の場合には、１時間後の曲げ強度が２．２ｍＰａであり、その後も強度の発現状態の進行が遅く、６時間後に漸く最高の強度が発現した。この様に、本発明で規定内のリチウム塩を含む急結剤を使用した場合、１時間の時点ですでに高い数値を示すのに比較して、消石灰のみの急結剤では、基準とする３．０ｍＰａの曲げ強度を得るには３時間以上必要とするため、天井部等の早期強度発現を必要とする箇所や、早期に施工を完了し稼働が要求される箇所での使用には適用できないことがわかる。
【００５７】
図２は、各表に示す例において、急結剤である消石灰スラリーにおける分散剤の添加量の違いによる粘性変化を示す対数グラフである。急結剤として、その粒度構成が、０．３μｍ＞を１０％と、０．３〜３０μｍ８２％と、３０μｍ＜８％の消石灰を３０重量％に対し、塩化リチウムをＬｉ_２Ｏ換算で外掛け１．８重量％添加したものに、分散剤の添加量を換えてテストした。分散剤は０．０１重量％と少量添加でも著しく粘性が低下する。その後添加量が増すと粘性が増大する傾向があり、１０重量％より多いと２００ｍＰａ・ｓ以上となるため作業性が悪く好ましくないことがわかる。
【００５８】
【発明の効果】
本発明のリチウム含有消石灰系スラリー系急結剤を使用することにより、従来の、消石灰系の急結剤を使用した場合に対し、急結剤中の固体粒子すなわち消石灰粒子の沈降抑制効果により吹付け材の硬化性状は安定化し、圧送中の吹付け材の粘性の抑制に加えて、急結性が不足であった吹き付けられた吹付け材の強度発現性を向上させ、施工が困難であった部位、たとえば天井部などの吊り下げ部の施工も可能となり、作業性も向上した。
【図面の簡単な説明】
【図１】リチウム塩添加と無添加で比較した養生強度の変化を示すグラフである。
【図２】急結剤における分散剤添加量の違いによる粘性変化を示す対数グラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a repair refractory formed by wet spraying of an irregular refractory material in various kilns and a quick setting agent for realizing rapid strength development of an initial lining.
[0002]
[Prior art]
Wet spraying of irregular refractory materials can be performed in a short time without a frame, and the construction body is denser than dry-type spraying construction, and can achieve the same quality as the casting construction body. From the viewpoint of cost reduction and cost reduction, it has been adopted as a furnace repair and initial lining construction method in various kilns. The use of slaked lime slurry as a quick setting agent in order to obtain the quick setting property of the sprayed construction body is disclosed in, for example, Japanese Examined Patent Publication No. 57-7350, Japanese Examined Patent Publication No. 2-27308, and Japanese Patent Publication No. 10-502574. Is disclosed.
[0003]
However, this wet spraying construction has problems such as stabilization of the properties of the spraying material, prevention of settling of the quick setting solid particles during spraying, and difficulty in controlling viscosity.
As a solution to this problem, the applicant of the present application specifies the particle size of slaked lime in the quick setting agent made of slaked lime slurry of Japanese Patent Application No. 11-294547, and further contains a dispersant, further a dispersion stabilizer or a foaming agent. Disclosed was formulated. However, since the strength development speed is still insufficient, particularly in the construction of spraying upward such as a ceiling portion that requires early curing, a sufficient effect cannot be exhibited.
[0004]
[Problems to be solved by the present invention]
The present invention measures the stabilization of the properties of the spray material, suppresses the viscosity during pumping, is excellent in preventing settling of the quick-setting solid particles during construction, and is capable of developing the strength of the sprayed spray material. It provides a quick setting agent for wet spraying of excellent irregular refractory materials.
[0005]
[Means for Solving the Problems]
The quick setting agent of the present invention does not merely accelerate the hardening of the cement, but immediately loses the fluidity by mixing the amorphous refractory material and the quick setting agent that are in a fluid state during spraying, and , Which exhibits the function of curing and making a relatively strong construction body, 5-60 wt% of slaked lime having a particle size configuration in which the particle size of 0.3 μm to 30 μm occupies 80% or more, and the balance from water comprising slaked lime slurry (hereinafter, simply referred to as "slurry".) to 100 wt%, and 0.01 to 10 wt% in terms of lithium salt Li ₂ O, dispersant outer 0.1 to 10% by weight It is a quick-setting agent for wet spraying construction that is added by hanging .
[0006]
The slaked lime used in the present invention can be selected from those produced by general industrial production. In order to obtain a good slaked lime slurry, the Japanese Industrial Standard (JIS R9001) No. 2 or more component, that is, a CaO component of 65% by weight or more. In order to obtain a strength development effect, a lithium salt is added.
[0007]
The slaked lime concentration of the slurry is preferably 5 to 60% by weight. If the slaked lime concentration is 5% by weight or less, the quick setting property is inferior, and the reactivity with the material is too small, so that the spraying material hangs down on the construction surface, and if the water in the slurry increases, the porosity of the construction body increases. The desired quality cannot be obtained due to strength and the like. On the other hand, if it exceeds 60% by weight, the slurry becomes too thick, the viscosity becomes high, and a whip shape is obtained. Therefore, it becomes difficult to pump and the quick setting agent pump for quick setting agent injection is clogged, and the kneading with the irregular refractory material becomes uneven, so that a good construction body cannot be obtained.
[0008]
That is, in a slurry having a high concentration of slaked lime, a large amount of dispersant is still required for lowering the viscosity, as in the case where the particle size of slaked lime described later contains more than 20% of particles smaller than 0.3 μm. In order to adversely affect the spray workability, the quality of the spray construction body, etc., the concentration should be 60% by weight or less.
[0009]
Lithium salts are known to accelerate the curing of amorphous refractory materials and can shorten the curing time. The mechanism of rapid setting is not clear, but it is thought that the rapid hardening is improved by the reaction between the aluminum ions eluted from the alumina cement and the lithium ions eluted from the lithium salt to produce lithium aluminate. This is considered to be different from the curing phenomenon. With regard to such rapid setting characteristics, we obtained the knowledge that when lime slurry and lithium salt are combined as a rapid setting agent, a significant improvement in quick setting is obtained, and we found the appropriate range from various verification experiments. It was.
[0010]
The lithium salt has a maximum effect as a rapid setting agent by mixing in the range of 0.01 to 10% by weight in terms of Li ₂ O with respect to 100% by weight of the slurry. 0.01% by weight If it is less, the effect of promoting rapid setting is not seen. When it exceeds 10% by weight, quick setting is good, but it causes explosion when dried.
[0011]
Many lithium salts such as lithium hydroxide, lithium chloride, lithium carbonate, lithium fluoride, lithium lactate, lithium phosphate, and lithium citrate can be used.
[0012]
The dispersing agent used for this invention should just be a substance with the dispersion effect which gives the fluidity | liquidity which can be pumped with respect to slaked lime slurry. For example, polyacrylates having an molecular weight of 15,000 or less, aromatic sulfonates, alkyl sulfonates, lignin sulfonates, polycarboxylates, polymer polycarboxylates, organophosphates, alkali metal carbonates, Inorganic phosphate and the like. These may be used alone or in combination of two or more.
[0013]
The viscosity adjustment of the slurry by dispersing the particles to which the dispersant has been added is preferably less than 200 mPa · s in order to obtain sufficient pumpability and sufficient mixing with the material, and should be added in an amount of 0.1 to 10% by weight based on the slurry. To achieve. If the amount is more than 10% by weight, the quick setting is inhibited, and if it is less than 0.1% by weight, there is no effect in reducing the viscosity.
[0014]
In the present invention, in order to further suppress slaked lime sedimentation and obtain a slurry with good dispersibility , slaked lime having a particle size configuration in which the particle size is 0.3 μm or more and 30 μm or less occupy 80% or more, specifically, 80% or more of particles having a particle size of 0.3 μm or more in the total amount of slaked lime, 80% or more of particles having a particle size of 30 μm or less in the total amount, and particles having a coarse particle size exceeding 30 μm and 0. It is possible to use particles whose particle size is adjusted so that particles in a fine particle region of less than 3 μm are each alone or in a total amount of 20% or less.
[0015]
Slaked lime containing more than a specified amount of particles having a particle size larger than 30 μm is adjusted in particle size by dry or wet grinding with a ball mill or the like. By using slaked lime with this regulated particle size range, the sedimentation rate of particles is slowed, so that water and particles do not separate during construction, and furthermore, by using a dispersant, the viscosity can be lowered and pumping can be easily performed. A slaked lime slurry quick setting agent that can be pumped and has good quick setting properties can be realized.
[0016]
When slaked lime containing more than 20% of particles larger than 30 μm is used, coarse particles settle out significantly, making it impossible to supply a constant concentration of rapid setting agent due to a difference in slurry concentration in the rapid setting agent tank. In the construction for several hours, separation of water and particles progresses and the viscosity of the slurry changes, so that the discharge amount becomes unstable and eventually becomes clogged in the pressure feeding pipe, making the construction impossible. In addition, if the particles smaller than 0.3 μm are contained in an amount of more than 20%, the sedimentation rate of the particles becomes much slower and there is no problem in separating the water and the particles, but the slurry becomes highly viscous and difficult to pump, and the viscosity is lowered. Therefore, a large amount of dispersing agent is required, and the reactivity of slaked lime is dulled, resulting in poor adhesion at the time of spraying and strength deterioration of the construction body.
[0017]
Even in the total amount of particles in the coarse particle region exceeding 30 μm and the fine particle region less than 0.3 μm, the particle size constitution within 20% means that the particle amount of 30 to 0.3 μm as the intermediate particle region is reduced. This is to prevent the adjustment of the viscosity and sedimentation speed of the slurry from being difficult to control.
[0018]
Furthermore, in the quick setting agent of the present invention, one or more dispersion stabilizers and / or foaming agents may be added as a settling inhibitor in the range of 0.05 to 5% by weight, alone or in combination. Thus, a rapid setting agent that suppresses separation and suppresses sedimentation can be obtained. In addition, the ratio which combines these is not specified, and can be used combining arbitrarily according to a condition.
[0019]
Dispersion stabilizers include inorganic thickeners such as silicic anhydride and clay, which have the effect of increasing viscosity by dissolving with water as a solvent and reducing the sedimentation rate of slaked lime particles, and an adsorption layer on the surface of slaked lime particles. For example, CMC. Has the effect of forming a sterically loose cross-linking bond between adjacent particles in the entire slurry and suppressing sedimentation. Water-soluble polymers such as PVA and polyacrylate having a molecular weight of 20,000 or more can be used. In addition, one or more substances selected from substances having the same effects as these can be selected and added according to the use conditions. The addition amount of these dispersion stabilizers is 0.05 to 5% by weight with respect to the slurry, and if it is less than 0.05% by weight, there is no thickening effect, and if it exceeds 5% by weight, the viscosity is large. Too much.
[0020]
The foaming agent has an effect of attaching bubbles to the particle surface and suppressing sedimentation by the buoyancy of the bubbles. For example, there are various surfactants such as lauryl sulfate and carboxylic acid, and one or more kinds can be selected and added from substances having the same effect as these. The appropriate addition amount is 0.05 to 5% by weight with respect to the slurry, and if it is less than 0.05% by weight, there is no settling suppression effect, and if it exceeds 5% by weight, there are too many bubbles, and quantitative pumping is not possible. It becomes difficult.
[0021]
The addition amount of the quick setting agent of the present invention to the spraying material is 0.01 to 5% by weight, more preferably 0.1 to 2% by weight, and the strength after 1 hour becomes higher.
[0022]
Accelerator of the present invention is adapted to spray material to the alumina cement the bond. In addition, the quick setting agent of this invention can be used, without receiving restrictions by construction conditions, such as an apparatus and hot construction.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described by way of examples shown in Tables 1 and 2 in comparison with comparative examples.
[0024]
All the slaked lime shown in each table had a CaO amount of 72.5% by weight, and tap water was used as the water.
[0025]
The slaked lime sedimentation was measured by placing 100 liters of a quick setting agent in a transparent plastic container having an inner diameter of 250 mm and measuring the time when a transparent water layer was formed on the top as the sedimentation start time.
[0026]
As a dispersing agent to be added separately as a quick setting agent, a polyacrylic acid soda having a molecular weight of 10,000, a polyacrylic acid soda having a molecular weight of 100,000 as a dispersion stabilizer in the case of increasing sedimentation suppression, A carboxylic acid system was used.
[0027]
For each sample, 6% by weight of water was added to a wet spray material containing alumina refractory raw material, ball clay, evaporated silica and alumina cement as a bond, and 0.5% by weight of the quick setting agent was poured into the quick setting agent tank. After standing for 1 hour, it was sprayed together with the material, and the strength development situation was measured.
[0028]
The strength manifestation state is that the refractory obtained by cutting a 40 × 40 × 160 piece from what was sprayed on the surface of a chamotte brick with a spraying material installed vertically was cured bending strength by three-point bending after 1 hour at room temperature 30 ° C. As a reference numerical value for comparison, it was made possible to perform construction work with a curing bending strength of 3.0 mPa or more after 1 hour.
[0029]
Examples 1 to 13 shown in Table 1 show slaked lime slurry-based quick-setting agents that use lithium salts within the specifications and add strength development effects. Moreover, Comparative Examples 1-5 show the example which measured the change of the characteristic value by lack of the dispersing agent with respect to an Example, lithium salt, the presence or absence of a precipitation inhibitor, and addition amount.
[0030]
The quick setting agent shown in Table 1 mainly uses an average particle size range of 0.3 to 30 μm without restricting the particle size of slaked lime, and uses lithium salt to accelerate the development of strength than before. This includes those that can be applied to use when construction can be completed within half a day.
[0031]
[Table 1]

In Reference Examples 1 to 10 shown in Table 1, lithium chloride was used as a lithium salt, and the characteristics were measured by changing the amount of slaked lime and the lithium salt within specifications. The viscosity is 200 mPa.s by the dispersant. It can be seen that it is lower than s and excellent in fluidity. The sedimentation start time also has a function of a dispersing agent, and each shows 6 hours or more. In particular, Reference Examples 8 to 10 to which a sedimentation inhibitor is added can extend the sedimentation start for 15 hours or more, and there is a time margin in work. It became possible to carry out.
[0032]
Result of measuring the strength development state of spraying refractory material using a quick-setting admixture with lithium salt for Reference Example, Reference Examples 3 to 10, not to mention the concentration of slaked lime 5% by weight and thin Reference is within the specified Also in Examples 1 and 2, after 1 hour, the standard value of 3.0 mPa was cleared, the effect of the strength development was obtained, and the work to the place where the early construction body formation was required became possible.
[0033]
Reference Examples 11 to 13 are examples in which the lithium salt up to Reference Example 10 was replaced with a different lithium salt, and after 1 hour, the cured bending strength already exceeded the reference value.
[0034]
Comparative Example 1 is an example in which only slaked lime is used within the specified range, but the workability is poor because there is no addition of a dispersant and the viscosity is too high, and sedimentation starts and can be used in about 3 hours without adding a settling inhibitor. There is a problem with time. The constructed refractory also had a desired bending strength of 1.5 mPa after 1 hour, and a desired construction body was not obtained.
[0035]
In Comparative Example 2, as in Comparative Example 1, only slaked lime is within the specified range, and since there is no addition of a dispersant or a settling inhibitor, the viscosity is too high and workability is poor. There is a problem. In addition, although lithium salt was added, the strength development was early because the usage ratio of lithium salt to slaked lime was too high, but cracking occurred due to explosion, and the curing bending strength after 1 hour could not exceed the standard value. Showed deterioration.
[0036]
In Comparative Example 3, since slaked lime exceeds 60% by weight, the slurry becomes too thick and the effect of the dispersant cannot be obtained. By adding the precipitation inhibitor to the specified maximum, the settling start time is as good as 14 hours later. However, the viscosity is high, it becomes difficult to pump, the quick setting agent pump for quick setting agent injection is clogged, and the mixed line with the irregular refractory material becomes uneven, there is no effect of adding lithium salt, The curing bending strength showed 1.3 mPa after 1 hour, and then cracks occurred due to explosion and the strength deteriorated.
[0037]
In Comparative Example 4, slaked lime was a small amount of 3% by weight, and the viscosity was 10 mPa · s due to the addition of the dispersant. However, even if the precipitation inhibitor was added, the precipitation suppression action did not work, and in 20 minutes. Sedimentation started. Moreover, since there was little slaked lime, there was almost no effect of addition of lithium salt, and the curing bending strength was not improved by the early strength development.
[0038]
Comparative Example 5 is an example in which 1.0% by weight of a dispersant is added to 30% by weight of slaked lime within a specified value, and the viscosity, the settling start time, etc. are all good, but since no lithium salt is added, the early strength The curing bending strength after 1 hour was 2.2 mPa and was not far from the target of the curing bending strength of 3.0 mPa after 1 hour of the present invention to obtain a construction body by expression.
[0039]
The examples shown in Table 2 are examples 1 to 12 in which the sedimentation rate is adjusted by regulating the particle size composition of slaked lime in addition to the lithium salt so that it can be applied even when construction is performed for a long time, and comparative example 6 thereto. -13 shows a slaked lime slurry quick-setting agent whose properties are determined by the presence or absence of a dispersant, a settling inhibitor, a small amount of addition, and a change in particle size constitution.
[0040]
The particle size of slaked lime in Table 2 was measured by a laser analysis method.
[0041]
[Table 2]

Examples 1 to 6 are examples in which the lithium salt was changed in accordance with the particle size constitution of slaked lime. In Example 1 , the amount of slaked lime used was 5% by weight, but the viscosity was low due to the dispersant. . Since the particle size composition is more than 30 μm but more than particles less than 0.3 μm, the sedimentation start is 12 hours later than other examples, but it has sufficient pot life, and the curing bending strength is also due to the lithium salt. After curing, the curing bending strength after 1 hour was 4.9 mPa, exceeding the target value of 3.0 mPa.
[0042]
In Examples 2 , 3 and 4 , the strength development state was observed by the change in the addition amount of the lithium salt. In Example 3 with a large amount of lithium salt, an improvement in strength higher than that in Examples 2 and 4 was observed in the curing bending strength of 9.5 mPa already after 1 hour.
[0043]
Examples 5 and 6 are examples in which a large amount of slaked lime is contained and the amount of particles less than 0.3 μm is used, and the sedimentation start time can be extended to 22 hours later. In order to lower the viscosity, the dispersant was adjusted to 3.0% by weight. Further, in Example 6 , the curing bending strength was superior to that of Example 5 by increasing the amount of lithium salt.
[0044]
Examples 7 , 8 and 9 are examples using lithium salts other than lithium chloride. In each case, the sedimentation start time was 18 hours later, and the curing bending strength sufficiently exceeded the standard 3.0 mPa after 1 hour. It was in a state.
[0045]
Examples 10 to 12 are examples of addition of a precipitation inhibitor, Example 10 was a dispersion stabilizer, Example 11 was a foaming agent, and Example 12 was the addition of both a dispersion stabilizer and a foaming agent. The sedimentation start time was 24 hours or more, and the curing music strength was sufficient.
[0046]
Comparative Examples 6 and 7 are examples in which the particle size composition of slaked lime is close to the limit of less than 0.3 μm, and particles exceeding 30 μm are set to a specified amount or more, and the total amount of both exceeds 20%. Since the amount of the lithium salt was used within the specified range, any strength development effect was obtained.
[0047]
However, in Comparative Example 6, the dispersant was 10% by weight and the dispersion stabilizer was also 5% by weight within the specified range. However, since a large amount of slaked lime exceeding 30 μm was added, the balance of the particle size constitution could not be maintained. The viscosity does not decrease to 400 mPa · s, and the sedimentation suppressing effect cannot be obtained, so that stable spraying work cannot be performed.
[0048]
In Comparative Example 7, the viscosity did not decrease to the specified value due to the excessive addition of a dispersion stabilizer and a foaming agent as a sedimentation inhibitor. The influence of was seen. Further, since the amount of slaked lime particle size exceeding 30 μm is too large and the settling start time is 40 minutes later and the pot life is short, a stable spraying operation cannot be performed.
[0049]
In Comparative Example 8, the amount of slaked lime is 5% by weight, which is the lowest within the specified range, and by setting the particle size to less than 0.3 μm and 28%, the balance of sedimentation with particles exceeding 30 μm occupying 18% is achieved. The sedimentation start time was 8 hours later, but when the total amount exceeds 20%, there are too many particles less than 0.3 μm and the viscosity does not decrease due to the dispersant, and the addition of lithium salt is within the specified range However, when the amount of slaked lime is small at about 2.0%, the effect of developing the strength cannot be obtained.
[0050]
Comparative Example 9 is an example in which particles of less than 0.3 μm of slaked lime are used in an amount of 26% or more as in Comparative Example 8, and the amount of slaked lime is sufficient at 30% by weight, and the strength development effect by the lithium salt is good. However, excessive fine particles helped to extend the sedimentation start time, but the viscosity due to the dispersant could not be lowered, which hindered the spraying operation.
[0051]
Comparative Example 10 is an example in which the amount of slaked lime is 70% by weight or more. Excess slaked lime could not lower the viscosity and the spraying work could not be completed.
[0052]
In Comparative Example 11, the amount of slaked lime itself was 4% by weight, which was smaller than the specified value, and it was insufficient to obtain the strength development effect by adding lithium salt.
[0053]
Since Comparative Examples 12 and 13 did not add a dispersant, both had high viscosity and could not be stably sprayed.
[0054]
FIG. 1 compares the curing bending strengths of Reference Example 9 and Comparative Example 5 shown in Table 1. As the refractory, an alumina cement bond wet amorphous refractory material was used.
[0055]
In the spray test, an irregular refractory material was kneaded with a mixer, and using an AP-10 swing valve pump manufactured by Allentown, a heavy duty hose having an inner diameter of 0.051 m (2 inches) and a length of 30.48 m (100 ft). The surface of the chamotte brick is installed vertically by adding compressed air of 0.55 mPa (80 psi) and 8.5 m ³ / min (300 cft) together with the quick setting agent at the spray nozzle part that is pumped inside and connected to the tip. It carried out by the method of spraying 150 mm thickness to (1 m < ² >).
[0056]
As shown in the figure, in the case of Reference Example 9, the strength is already 8.5 mPa after 1 hour, and after about 2.5 hours, the maximum strength is exhibited and the strength is sufficient to improve the working efficiency. Show. On the other hand, in the case of Comparative Example 5, the bending strength after 1 hour was 2.2 mPa, the progress of the strength development state was slow thereafter, and the maximum strength was gradually developed after 6 hours. In this way, when the quick setting agent containing the lithium salt specified in the present invention is used, the quick setting agent of only slaked lime is used as a standard, compared with already showing a high value at 1 hour. It takes 3 hours or more to obtain a bending strength of 3.0 mPa, so it is applicable for use in places where early strength development is required, such as ceilings, or where construction is completed early and operation is required. I understand that I can't.
[0057]
FIG. 2 is a logarithmic graph showing changes in viscosity due to differences in the amount of dispersant added to the slaked lime slurry, which is a quick setting agent, in the examples shown in each table. As the quick setting agent, the particle size composition is 0.3 μm> 10%, 0.3-30 μm82%, 30 μm <8% slaked lime 30% by weight, and lithium chloride as Li ₂ O conversion A test was conducted by changing the added amount of the dispersant to the one added by 1.8% by weight. The viscosity of the dispersant is remarkably lowered even when added in a small amount of 0.01% by weight. Thereafter, when the amount added is increased, the viscosity tends to increase, and when it is more than 10% by weight, it is 200 mPa · s or more, so that it is not preferable because workability is poor.
[0058]
【The invention's effect】
By using the lithium-containing slaked lime-based slurry-based rapid accelerating agent of the present invention, compared with the conventional case of using a slaked lime-based rapid accelerating agent, the solid particles in the accelerating agent, that is, the slaked lime particles are prevented from sinking. The curing property of the adhesive material was stabilized, and in addition to suppressing the viscosity of the spraying material during pumping, it improved the strength development of the sprayed material that was insufficient in quick setting, making construction difficult. In addition, it is possible to construct hanging parts such as ceiling parts, and workability is improved.
[Brief description of the drawings]
FIG. 1 is a graph showing changes in curing strength compared with and without addition of a lithium salt.
FIG. 2 is a logarithmic graph showing a change in viscosity due to a difference in the amount of dispersant added to the quick setting agent.

Claims

5 to 60% by weight of slaked lime having a particle size composition in which a particle size of 0.3 μm or more and 30 μm or less occupies 80% or more is a quick setting agent for wet spraying construction added to a wet spraying material containing alumina cement In addition, 100% by weight of the slaked lime slurry consisting of water with respect to slaked lime slurry , 0.01 to 10% by weight of a lithium salt in terms of Li ₂ O, and 0.1 to 10% by weight of a dispersing agent are added on the outside. Quick setting agent for spray construction .

Furthermore, the quick setting agent of Claim 1 which added the dispersion stabilizer and / or the foaming agent as a sedimentation inhibitor over the slaked lime slurry 0.05-5 weight%.