JP4960541B2 - Magnesia-alumina-titania brick - Google Patents
Magnesia-alumina-titania brickInfo
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- JP4960541B2 JP4960541B2 JP2000068671A JP2000068671A JP4960541B2 JP 4960541 B2 JP4960541 B2 JP 4960541B2 JP 2000068671 A JP2000068671 A JP 2000068671A JP 2000068671 A JP2000068671 A JP 2000068671A JP 4960541 B2 JP4960541 B2 JP 4960541B2
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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
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/66—Monolithic refractories or refractory mortars, including those whether or not containing clay
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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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B2235/3206—Magnesium oxides or oxide-forming salts thereof
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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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
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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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B2235/3222—Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
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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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
- C04B2235/3232—Titanium oxides or titanates, e.g. rutile or anatase
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- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、耐食性および耐スポーリング性に優れたマグネシア−アルミナ−チタニア質れんがに関する。
【０００２】
【従来の技術】
耐食性および耐スポーリング性を兼ね備えた塩基性れんが材質として、マグネシア−クロム質れんがが知られている。このマグネシア−クロム質れんがは、クロム成分の含有によって環境衛生面で問題がある。
【０００３】
そこで、クロム成分を含有しない、いわゆるクロムフリーれんがとしてマグネシア−アルミナ−チタニア質れんがが提案されている。例えば特開平7-300361号公報に見られるとおりである。
【０００４】
マグネシア−アルミナ−チタニア質れんがは、使用中の高温下でマグネシアとアルミナとの反応によってスピネルを生成する。また、チタニアがスラグのＣａＯ成分と反応してＣａＯ・ＴｉＯ2を生成する。これらの生成物はいずれもれんが稼動面の組織を緻密化し、れんが組織へのスラグ浸透を防止する。
【０００５】
さらに、れんが焼成過程で生成されるＭｇＡｌ2Ｏ4-Ｍｇ2ＴｉＯ4等の固溶体の存在により、れんが組織の耐スポーリング性が向上する。
【０００６】
【発明が解決しようとする課題】
マグネシア原料は膨張係数の大きな耐火原料である。マグネシア−アルミナ−チタニア質れんがはこの膨張係数の大きいマグネシア原料の配合割合が多いことから、耐スポーリング性においては依然十分なものではない。
【０００７】
溶鋼容器等の工業窯炉の操業は、一般に加熱−冷却を繰り返す。このため、従来材質のマグネシア−アルミナ−チタニア質れんがでは、耐スポーリング性がネックとなって内張り材として十分な耐用性が得られない。
本発明はマグネシア−アルミナ−チタニア質れんがにおいて、その耐スポーリング性の改善を図ることを目的とする。
【０００８】
【課題を解決するための手段】
本発明の特徴とするところは、耐火骨材としてアルミナ原料１〜20質量％、チタニア原料1〜15質量％、マグネシア原料70〜95質量％を含み、且つ前記マグネシアのうち耐火骨材全体に占める割合で50質量％以上を、化学成分値でＳｉＯ2を0.1〜1質量％含む電融マグネシアとし、この配合組成を混練、成形、焼成したマグネシア−アルミナ−チタニア質れんがである。
【０００９】
マグネシア−アルミナ−チタニア質れんがの耐スポーリング性を向上させる手段として、ＭｇＯ・Ａｌ2Ｏ3系スピネル原料（以下、スピネル原料と称する。）の添加がある。
【００１０】
スピネル原料は低膨張性である。しかし、耐スポーリング性を十分に改善させるには、スピネル原料の配合量を相当多くする必要があり、その分、マグネシア原料の割合が少なくなって耐食性の低下を招く。
【００１１】
本発明はマグネシア−アルミナ−チタニア質れんがにおいて、マグネシア原料としてＳｉＯ2を0.1〜1質量％含む電融マグネシア原料を使用したことにより、耐食性を低下させることなく、耐スポーリング性の改善を図ることができたものである。その詳細な機構は不明であるが、本発明によるこの効果は以下の理由によるものと思われる。
【００１２】
マグネシア−アルミナ−チタニア質れんがは焼成過程の高温下で、マグネシア原料とアルミナ原料との反応によるスピネルを生成する。一方、チタニア原料とアルミナ原料との反応でチタン酸アルミニウムが生成される。そして、前記スピネルとチタン酸アルミニウムとの反応によって固溶体が生成する。
【００１３】
本発明のれんが材質は、電融マグネシア原料に含まれるＳｉＯ2成分が媒体となってマグネシア原料とアルミナ原料との反応によるスピネル生成が促進され、その後のチタン酸アルミニウムとスピネルとの反応による固溶体の生成が、急速に行なわれる。これにより、固溶体組成が従来材質に見られるＭｇＡｌ2Ｏ4−Ｍｇ2ＴｉＯ4から本発明材質ではＡｌ2ＴｉＯ5−ＭｇＴｉ ２ Ｏ5に変化し、焼成過程でれんが組織に形成される気孔の形状が複雑になるだけでなく、その気孔径が大きくなることで、熱膨張応力の分散とれんが組織の強度向上が図られる。その結果、耐スポーリング性が大幅に向上する。
【００１４】
焼結マグネシア原料では、同量のＳｉＯ2成分を含んでいても前記本発明の効果は得られない。焼結マグネシア原料は電融マグネシア原料に比べて結晶粒径が小さいため、チタニア質原料からのＴｉＯ２成分が結晶粒界に浸透し、マグネシア原料の粒子崩壊によって耐スポーリング性の向上が認められない。また、この粒子崩壊は耐食性低下の原因にもなる。
【００１５】
【発明の実施の形態】
本発明で使用するアルミナ原料としては、焼結アルミナ、電融アルミナ、仮焼アルミナ、ばん土けつ岩、シリマナイト、ボーキサイト等である。このうち、仮焼アルミナは微粉のため、微粉部の使用に限られる。
【００１６】
耐火骨材中に占めるアルミナ原料の割合は、1質量％未満では固溶体（Ａｌ２ＴｉＯ５−ＭｇＴｉ ２ Ｏ５）の生成量が不足するためか、耐スポーリング性に劣る。20質量％を超えるとマグネシア原料の割合が少なくなって耐食性に劣る。さらに好ましい範囲は、3〜15質量％である。
【００１７】
チタニア原料は天然品、人工品のいずれでもよい。ルチル型、アナターゼ型等があるが、経済性の面から天然品である金紅石（ルチル型）の使用が好ましい。耐火骨材中に占める割合は、1質量％未満では固溶体（Ａｌ２ＴｉＯ５−ＭｇＴｉ ２ Ｏ５）の生成量が不足するためか、耐スポーリング性の効果が得られない。チタニア原料が耐火性の低い原料のため、15質量％を超えると耐食性の低下を招く。さらに好ましくは2〜10質量％である。
【００１８】
マグネシア原料は、焼結マグネシア、電融マグネシア、天然マグネシア等を使用する。耐火骨材に占める割合は、70重量％未満では耐食性が低下し、95重量％を超えると耐スポーリング性の効果が不十分となる。
【００１９】
本発明では、このマグネシア原料のうち耐火骨材全体に占める割合で、50質量％以上を、化学成分値でＳｉＯ2を0.1〜1質量％含む電融マグネシア原料とする。
電融マグネシア原料は一般に焼結マグネシア原料に比べて高純度である。本発明で使用する電融マグネシアはＳｉＯ2を0.1〜1質量％含み、電融マグネシアの中では低純度品に相当する。
【００２０】
低純度の耐火原料は通常、耐食性低下の原因となるが、本発明で使用する電融マグネシア原料は前記のように、他の特定の耐火原料との組み合わせによって耐スポーリング性、耐食性共に優れた効果を発揮する。
【００２１】
電融マグネシアに含むＳｉＯ2量は、0.1質量％未満では耐スポーリング性の効果が得られず、1質量％を超えると耐食性が低下する。さらに好ましくは0.2〜1質量％である。
【００２２】
本発明は、このＳｉＯ2を0.1〜1質量％含む電融マグネシアを、耐火骨材全体に占める割合で50質量％以上使用する。さらに好ましくは、70質量％以上使用する。
【００２３】
他のマグネシア原料と併用する場合、他のマグネシア原料としては焼結マグネシア原料、天然マグネシア原料、ＳｉＯ2を0.1質量％未満含む電融マグネシア原料等が挙げられる。
【００２４】
耐火骨材は本発明の効果を損なわない範囲で、更に他の上記以外の耐火原料を併用してもよい。例えば、焼結または電融のスピネル原料を28重量％以下の範囲で併用してもよい。
【００２５】
スピネル原料はＭｇＯ・Ａｌ2Ｏ３系スピネルを主材にした耐火原料であって、耐食性および耐スポーリング性に優れている。しかし、マグネシア原料に比べると耐食性に劣ることから、耐火骨材に占める割合で28重量％を超えるとれんがの耐食性が劣る。
【００２６】
耐火骨材の粒度は、れんが組織が密充填組織となるように、粗粒、中粒、微粒に適宜調整する。また、アルミナ原料、チタニア原料およびスピネル原料は使用量が少ないために、れんが組織中へより均一に分散するように、微粒主体で使用することが好ましい。
【００２７】
耐火骨材以外に、必要によっては揮発シリカ、耐火粘土、ガラス類等の焼結助剤を添加してもよい。これらは、本発明の耐食性の効果を損なわないためにも、その添加量は耐火骨材に対する外掛けで5質量％以下、さらに好ましくは3質量％以下とする。
【００２８】
結合剤の種類は従来と特に変わりない。例えばリグニン類、糖類、でんぷん類、メチルセルロース類、リン酸類等の水溶液、あるいはフェノール樹脂、酢酸ビニルエマルジョン等が使用できる。添加量は、耐火骨材に対して外掛け1〜5質量％である。
【００２９】
れんがの加圧成形、焼成の手段についても従来材質と特に変わりない。成形は、前記骨材組成に結合剤を添加し、混練後、フリクションプレス、オイルプレス等で任意形状に成形する。焼成は1600〜1900℃程度の温度領域で行なう。
【００３０】
【実施例】
表1は本発明実施例および比較例において使用した耐火骨材の化学成分値である。表2は本発明実施例、表3はその比較例である。また表2、表3には各例の試験結果を併記する。
【００３１】
各例は表に示す耐火骨材100質量％に対し、結合剤としてリグニンスルフォン酸溶液を外掛け3質量％添加し、混練したものをフリクションプレスにて並形形状に加圧成形後、1700℃にて焼成した焼成れんがである。試験方法は次ぎのとおり。
【００３２】
耐スポーリング性の試験は、1400℃に昇温済みの電気炉に対し、試験片をその長さ方向の片側を挿入し、30分間加熱後、取り出して強制空冷し、試験片が剥落に至るまでの回数を求めた。
【００３３】
耐食性の試験は、1600℃下での回転侵食試験で行なった。侵食剤は質量比で1：1組み合わせた鋼片および転炉スラグとした。試験片の損耗寸法を測定し、比較例1の溶損寸法を溶損寸法を100とした指数で示した。数値が小さいほど耐食性に優れる
【００３４】
実機耐用性は、ＲＨ式溶鋼真空脱ガス装置に内張りし、損耗速度をｍｍ／チャージで求めた。
【００３５】
【表１】
【表２】
【表３】
表2、3の試験結果のとおり、本発明実施例はいずれも耐食性と耐スポーリング性を兼ね備え、その耐用性向上の効果は実機試験から確認される。
【００３９】
同じマグネシア−アルミナ−チタニア質れんがであっても、マグネシア原料がすべて焼結品の比較例1、ＳｉＯ2量が本発明の限定範囲より少ない電融マグネシアを使用した比較例2、ＳｉＯ2量が本発明の限定範囲した範囲内にある電融マグネシアを使用しているがその割合が本発明の範囲より少ない比較例3は、いずれも耐スポーリング性に劣る。また、チタニア原料が多すぎる比較例4は、耐食性が大幅に低下する。
【００４０】
比較例5、比較例6は、マグネシア−アルミナ質れんがであって、チタニア原料を含んでいない。このうち比較例5は、ＳｉＯ2量が本発明の限定範囲内の電融マグネシアを使用した。比較例6は、ＳｉＯ2量が本発明の限定範囲より少ない電融マグネシアを使用したものである。
【００４１】
この比較例5、比較例6の試験結果から、マグネシア−アルミナ質れんがはチタニア原料を含まないことで電融マグネシアのＳｉＯ2量に関係なく、耐スポーリング性に劣り、本発明の効果が得られない。
【００４２】
実施例1の耐火物配合組成をベースに、電融マグネシア原料の種類のみを表1に示した電融マグネシア原料Ａ〜Ｆに変化させてマグネシア−アルミナ−チタニア質れんがを得た。図1は、各れんがの耐スポーリング性の試験をし、その結果をグラフで示したものである。
【００４３】
このグラフからも、本発明で限定した範囲内のＳｉＯ2を含有する電融マグネシア原料の使用がマグネシア−アルミナ−チタニア質れんがの耐スポーリング性の向上効果があることが確認される。
【００４４】
【発明の効果】
本発明によるマグネシア−アルミナ−チタニア質れんがはの効果は、優れた耐用性のみならず、環境衛生面で好ましいクロムフリー材質であることにある。その用途例は、各種の溶鋼・溶銑容器、溶鋼・溶銑処理装置、廃棄物焼却炉・溶融炉、ロータリーキルン等が挙げられる。
【図面の簡単な説明】
【図１】マグネシア−アルミナ−チタニア質れんがにおいて、電融マグネシア原料の種類と耐スポーリング性の関係を示したグラフ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnesia-alumina-titania brick excellent in corrosion resistance and spalling resistance.
[0002]
[Prior art]
As the basic bricks material that combines corrosion resistance and spalling resistance, Ma grayed Indonesia - are known chromium bricks. The Ma grayed Indonesia - chrome brick is a problem in environmental hygiene by the inclusion of chromium component.
[0003]
Therefore, magnesia-alumina-titania brick has been proposed as a so-called chromium-free brick that does not contain a chromium component. For example, as disclosed in JP-A-7-300361.
[0004]
Magnesia-alumina-titania bricks produce spinel by reaction of magnesia and alumina at the high temperatures during use. Further, titania reacts with CaO component of the slag to produce a CaO · TiO 2. All of these products densify the working structure of the brick and prevent slag penetration into the brick structure.
[0005]
Furthermore, the presence of a solid solution such as MgAl 2 O 4 —Mg 2 TiO 4 produced during the baking process improves the spalling resistance of the brick structure.
[0006]
[Problems to be solved by the invention]
The magnesia raw material is a refractory raw material having a large expansion coefficient. Magnesia-alumina-titania bricks are still insufficient in spalling resistance because of the large proportion of magnesia raw material having a large expansion coefficient.
[0007]
The operation of an industrial kiln such as a molten steel container generally repeats heating and cooling. For this reason, in the conventional material magnesia-alumina-titania brick, spalling resistance becomes a bottleneck and sufficient durability as a lining material cannot be obtained.
The object of the present invention is to improve the spalling resistance of magnesia-alumina-titania bricks.
[0008]
[Means for Solving the Problems]
The feature of the present invention is that it includes 1-20% by mass of alumina raw material, 1-15% by mass of titania raw material, 70-95% by mass of magnesia raw material as a refractory aggregate, and occupies the entire refractory aggregate of magnesia. A magnesia-alumina-titania brick obtained by kneading, molding, and firing this blended composition is 50 mass% or more in terms of a ratio, and electrofused magnesia containing 0.1 to 1 mass% of SiO 2 as a chemical component value.
[0009]
As a means for improving the spalling resistance of the magnesia-alumina-titania brick, there is an addition of an MgO.Al 2 O 3 spinel raw material (hereinafter referred to as a spinel raw material).
[0010]
Spinel raw materials are low expansion. However, in order to sufficiently improve the spalling resistance, it is necessary to considerably increase the blending amount of the spinel raw material, and accordingly, the proportion of the magnesia raw material is reduced and the corrosion resistance is lowered.
[0011]
In the present invention, in magnesia-alumina-titania brick, by using an electrofused magnesia raw material containing 0.1 to 1% by mass of SiO 2 as a magnesia raw material, the spalling resistance is improved without reducing the corrosion resistance. Was made. Although the detailed mechanism is unknown, this effect by this invention is considered to be based on the following reasons.
[0012]
The magnesia-alumina-titania brick generates spinel by the reaction between the magnesia raw material and the alumina raw material at a high temperature during the firing process. On the other hand, aluminum titanate is produced by the reaction between the titania raw material and the alumina raw material. And a solid solution produces | generates by reaction of the said spinel and aluminum titanate.
[0013]
In the brick material of the present invention, the SiO 2 component contained in the electrofused magnesia raw material serves as a medium to promote the formation of spinel by the reaction between the magnesia raw material and the alumina raw material, and then the solid solution formed by the reaction between the aluminum titanate and the spinel. Generation is rapid. As a result, the solid solution composition changes from MgAl 2 O 4 —Mg 2 TiO 4 found in the conventional material to Al 2 TiO 5 —MgTi 2 O 5 in the material of the present invention, and the shape of the pores formed in the brick structure during the firing process Not only becomes complicated, but also increases the pore diameter, thereby dispersing the thermal expansion stress and improving the strength of the brick structure. As a result, the spalling resistance is greatly improved.
[0014]
Even if the sintered magnesia raw material contains the same amount of SiO 2 component, the effect of the present invention cannot be obtained. Since the sintered magnesia material has a smaller crystal grain size than the electrofused magnesia material, the TiO 2 component from the titania material penetrates into the grain boundaries, and the spalling resistance is improved by the particle collapse of the magnesia material. Absent. Moreover, this particle collapse also causes a decrease in corrosion resistance.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the alumina raw material used in the present invention include sintered alumina, fused alumina, calcined alumina, porphyry shale, sillimanite, bauxite and the like. Of these, calcined alumina is fine and is limited to the use of fine powder.
[0016]
If the proportion of the alumina raw material in the refractory aggregate is less than 1% by mass, the amount of generated solid solution (Al 2 TiO 5 —MgTi 2 O 5 ) is insufficient, or the spalling resistance is poor. If it exceeds 20% by mass, the proportion of the magnesia raw material decreases and the corrosion resistance is poor. A more preferable range is 3 to 15% by mass.
[0017]
The titania raw material may be either a natural product or an artificial product. Although there are a rutile type and an anatase type, it is preferable to use a natural red gold (rutile type) from the viewpoint of economy. If the proportion in the refractory aggregate is less than 1% by mass, the effect of spalling resistance cannot be obtained because the amount of solid solution (Al 2 TiO 5 —MgTi 2 O 5 ) produced is insufficient. Since the titania raw material is a raw material with low fire resistance, if it exceeds 15% by mass, the corrosion resistance is lowered. More preferably, it is 2-10 mass%.
[0018]
As the magnesia raw material, sintered magnesia, electrofused magnesia, natural magnesia or the like is used. When the proportion of the refractory aggregate is less than 70% by weight, the corrosion resistance decreases, and when it exceeds 95% by weight, the effect of the spalling resistance becomes insufficient.
[0019]
In the present invention, 50% by mass or more of the magnesia raw material as a proportion of the entire refractory aggregate is used as an electrofused magnesia raw material containing 0.1 to 1% by mass of SiO 2 as a chemical component value.
Electrofused magnesia materials are generally of higher purity than sintered magnesia materials. The electrofused magnesia used in the present invention contains 0.1 to 1% by mass of SiO 2 and corresponds to a low-purity product among electrofused magnesia.
[0020]
Low purity refractory raw materials usually cause a decrease in corrosion resistance, but as described above, the fused magnesia raw material used in the present invention has excellent spalling resistance and corrosion resistance in combination with other specific refractory raw materials. Demonstrate the effect.
[0021]
If the amount of SiO 2 contained in the electrofused magnesia is less than 0.1% by mass, the effect of spalling resistance cannot be obtained, and if it exceeds 1% by mass, the corrosion resistance decreases. More preferably, it is 0.2-1 mass%.
[0022]
In the present invention, 50% by mass or more of the electrofused magnesia containing 0.1 to 1% by mass of SiO 2 is used in the proportion of the entire refractory aggregate. More preferably, 70% by mass or more is used.
[0023]
When used in combination with other magnesia materials, examples of other magnesia materials include sintered magnesia materials, natural magnesia materials, and fused magnesia materials containing less than 0.1% by mass of SiO 2 .
[0024]
The refractory aggregate may be used in combination with other refractory raw materials other than those described above as long as the effects of the present invention are not impaired. For example, a sintered or electrofused spinel material may be used in combination within a range of 28% by weight or less.
[0025]
Spinel raw material is a refractory raw material in which the Mg O · Al 2 O 3 spinel in main material, has excellent corrosion resistance and spalling resistance. However, since the corrosion resistance is inferior to that of the magnesia raw material, the corrosion resistance of the brick is inferior when it exceeds 28% by weight in the proportion of the refractory aggregate.
[0026]
The particle size of the refractory aggregate is appropriately adjusted to coarse particles, medium particles, and fine particles so that the brick structure becomes a closely packed structure. Further, since the alumina raw material, titania raw material and spinel raw material are used in a small amount, it is preferably used mainly with fine particles so that the brick is more uniformly dispersed in the structure.
[0027]
In addition to the refractory aggregate, if necessary, a sintering aid such as volatile silica, refractory clay, and glass may be added. In order not to impair the corrosion resistance effect of the present invention, the amount added is 5% by mass or less, more preferably 3% by mass or less, as an outer coating with respect to the refractory aggregate.
[0028]
The type of binder is not particularly different from the conventional one. For example, aqueous solutions of lignins, sugars, starches, methylcelluloses, phosphoric acids, etc., phenol resins, vinyl acetate emulsions and the like can be used. The amount added is 1-5% by mass on the outer side of the refractory aggregate.
[0029]
The pressure molding and baking means of bricks are not particularly different from conventional materials. The molding is performed by adding a binder to the aggregate composition, kneading, and molding into an arbitrary shape using a friction press, an oil press or the like. Firing is performed in a temperature range of about 1600 to 1900 ° C.
[0030]
【Example】
Table 1 shows chemical component values of the refractory aggregate used in the examples of the present invention and comparative examples. Table 2 shows examples of the present invention, and Table 3 shows comparative examples. Tables 2 and 3 also show the test results of each example.
[0031]
In each example, 3% by mass of a lignin sulfonic acid solution was added as a binder to 100% by mass of the refractory aggregate shown in the table, and the kneaded product was pressure-molded into a parallel shape using a friction press, then 1700 ° C Baking bricks fired at The test method is as follows.
[0032]
In the spalling resistance test, for an electric furnace heated to 1400 ° C, insert one side of the test piece in the length direction, heat it for 30 minutes, take it out, forcibly cool it down, and the test piece comes off. The number of times until was determined.
[0033]
The corrosion resistance test was conducted by a rotary erosion test at 1600 ° C. The erodants were steel slabs and converter slag combined 1: 1 by mass. The wear size of the test piece was measured, and the melt size of Comparative Example 1 was shown as an index with the melt size as 100. The smaller the value, the better the corrosion resistance. [0034]
The actual machine durability was determined by lining the RH type molten steel vacuum degassing apparatus and determining the wear rate in mm / charge.
[0035]
[Table 1]
[Table 2]
[Table 3]
As shown in the test results of Tables 2 and 3, each of the Examples of the present invention has both corrosion resistance and spalling resistance, and the effect of improving the durability is confirmed from the actual machine test.
[0039]
Even in the same magnesia-alumina-titania brick, Comparative Example 1 in which all the magnesia raw materials were sintered products, Comparative Example 2 in which the amount of SiO 2 was less than the limited range of the present invention, and the amount of SiO 2 was Although the electrofused magnesia within the limited range of the present invention is used, the comparative example 3 whose ratio is less than the range of the present invention is inferior in spalling resistance. Further, in Comparative Example 4 in which there are too many titania raw materials, the corrosion resistance is greatly reduced.
[0040]
Comparative Examples 5 and 6 are magnesia-alumina bricks and do not contain a titania raw material. Of these, Comparative Example 5 used electrofused magnesia whose SiO 2 amount was within the limited range of the present invention. In Comparative Example 6, electrofused magnesia having a SiO 2 content less than the limited range of the present invention was used.
[0041]
From the test results of Comparative Example 5 and Comparative Example 6, the magnesia-alumina brick does not contain titania raw materials, so that the spalling resistance is inferior regardless of the amount of SiO 2 in the fused magnesia, and the effect of the present invention is obtained. I can't.
[0042]
Based on the refractory blend composition of Example 1, only the type of electrofused magnesia material was changed to electrofused magnesia materials A to F shown in Table 1 to obtain magnesia-alumina-titania bricks. Fig. 1 is a graph showing the results of testing the spalling resistance of each brick.
[0043]
Also from this graph, it is confirmed that the use of the fused magnesia raw material containing SiO 2 within the range limited in the present invention has an effect of improving the spalling resistance of the magnesia-alumina-titania brick.
[0044]
【Effect of the invention】
The effect of the magnesia-alumina-titania brick according to the present invention is that it is a chromium-free material that is preferable not only in terms of excellent durability but also in terms of environmental hygiene. Examples of the application include various types of molten steel / molten metal containers, molten steel / molten metal treatment apparatuses, waste incinerators / melting furnaces, rotary kilns, and the like.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the type of electrofused magnesia raw material and spalling resistance in magnesia-alumina-titania bricks.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000068671A JP4960541B2 (en) | 2000-03-08 | 2000-03-08 | Magnesia-alumina-titania brick |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2000068671A JP4960541B2 (en) | 2000-03-08 | 2000-03-08 | Magnesia-alumina-titania brick |
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| JP2001253765A JP2001253765A (en) | 2001-09-18 |
| JP4960541B2 true JP4960541B2 (en) | 2012-06-27 |
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| JP5850571B2 (en) * | 2012-01-24 | 2016-02-03 | 黒崎播磨株式会社 | Basic brick |
| JP6005545B2 (en) * | 2013-02-15 | 2016-10-12 | 黒崎播磨株式会社 | Calcined basic brick |
| CN110054504A (en) * | 2019-04-30 | 2019-07-26 | 浙江琰大新材料有限公司 | A kind of magnalium titanium brick that heat preservation and insulation is good |
| CN116606161A (en) * | 2023-05-25 | 2023-08-18 | 攀枝花学院 | Method for preparing porous ceramic from titanium-containing blast furnace slag and silicon slag |
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