JP2603387C - - Google Patents
Info
- Publication number
- JP2603387C JP2603387C JP2603387C JP 2603387 C JP2603387 C JP 2603387C JP 2603387 C JP2603387 C JP 2603387C
- Authority
- JP
- Japan
- Prior art keywords
- zirconia
- magnesia
- stabilized zirconia
- raw material
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 72
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 40
- 239000002994 raw material Substances 0.000 claims description 28
- 229910002085 magnesia-stabilized zirconia Inorganic materials 0.000 claims description 21
- 239000000395 magnesium oxide Substances 0.000 claims description 20
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 claims description 19
- 239000011449 brick Substances 0.000 claims description 16
- GEIAQOFPUVMAGM-UHFFFAOYSA-N oxozirconium Chemical compound [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 238000001354 calcination Methods 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 description 14
- 239000010959 steel Substances 0.000 description 14
- 239000002893 slag Substances 0.000 description 13
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium monoxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 8
- 238000001764 infiltration Methods 0.000 description 8
- 239000010410 layer Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 7
- 230000035939 shock Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 239000000292 calcium oxide Substances 0.000 description 5
- 235000012255 calcium oxide Nutrition 0.000 description 5
- 239000011362 coarse particle Substances 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 229910002084 calcia-stabilized zirconia Inorganic materials 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 238000009740 moulding (composite fabrication) Methods 0.000 description 4
- 230000003628 erosive Effects 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000003405 preventing Effects 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 229910052596 spinel Inorganic materials 0.000 description 2
- 239000011029 spinel Substances 0.000 description 2
- 229910002076 stabilized zirconia Inorganic materials 0.000 description 2
- 210000001519 tissues Anatomy 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N AI2O3 Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 241000282941 Rangifer tarandus Species 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 235000013379 molasses Nutrition 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000011163 secondary particle Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000004901 spalling Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N sulfonic acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- 230000002522 swelling Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Description
【発明の詳細な説明】
０００１
産業上の利用分野
本発明は、溶鋼の連続鋳造用タンディッシュノズルまたは溶鋼の流量コントロ
ール用のプレートれんがに適したジルコニア質れんがの製造方法に関する。
０００２
従来の技術
溶鋼の連続鋳造において、タンディッシュノズルやプレートれんがのノズル孔
は、溶鋼流による摩耗の他に溶鋼中の成分による化学的侵食を受けるため、緻密
なジルコニア質耐火物が使用されている。
０００３
例えば、特開昭53−94311号公報には、７４μｍ以下の粒子から造粒された２
次粒子から気孔率１０％以下の緻密耐火材料を製造する方法が開示されている。
また、特開昭61−21968号公報には、天然産バデライトサンドと安定化剤を０.３
〜０.０１ｍｍに混合粉砕し、造粒後、成形、焼成することからなるタンディッ
シュノズル用ジルコニア質耐火物の製法が開示されている。
０００４
また、カルシアによって安定化されたジルコニア原料を粗粒から微粉までの連
続粒度として常法により混練、成形、焼成した気孔率２０％以上のタンデッシュ
ノズルは一般に使用されている。
０００５
発明が解決しようとする課題
カルシア安定化ジルコニアの粗粒を含み、気孔率２０％クラスのジルコニア質
れんがは比較的耐スポール性に優れ、大型形状やノズル孔が大きい場合には、割
れ難いという長所があるが、Ｃａ添加鋼、高酸素鋼などを受鋼した場合に、スラ
グの浸潤が大きく、厚い変質層を形成し、構造的スポーリングにより剥離や表面
からの溶損により大きく損傷される。
０００６
また、０.３ｍｍ以下の微粉のみからなる緻密なジルコニア質れんがは高強度
、高耐食性である反面、耐熱衝撃性に劣るという欠点があり、大型形状やノズル
孔が大きい場合には、割れ易く、エッジ部の欠落なども起こり易い。更に、この
ような微粉構成のれんがは成形性が悪く、造粒処理が必要であり、また、焼成時
の収縮が大きいために大型形状品の製造は困難であった。
０００７
従って、本発明の目的は、上記問題点を解決し、耐食性に優れ、かつ耐熱衝撃
性に優れ、溶鋼の連続鋳造用タンディッシュノズルまたは溶鋼の流量コントロー
ル用のプレートれんがに適したジルコニア質れんがの製造方法を提供することに
ある。
０００８
課題を解決するための手段
従って、本発明のジルコニア質れんがの製造方法は、ＭｇＯ含量が２〜６重量
％で、残部が実質上ジルコニアからなるマグネシア安定化ジルコニア及び／また
はマグネシア部分安定化ジルコニア原料を５０〜９０重量％、及びＺｒＯ2とし
て９５重量％以上の純度の未安定化ジルコニア原料を１０〜５０重量％含有して
なり、且つ該マグネシア安定化ジルコニア及び／またはマグネシア部分安定化ジ
ルコニア原料の１０〜４０重量％（マグネシア安定化ジルコニア及び／またはマ
グネシア部分安定化ジルコニア原料と未安定化ジルコニア原料の合計量を基準と
して）が粒度１.４〜０.３ｍｍで、マグネシア安定化ジルコニア及び／またはマ
グネシア部分安定化ジルコニア原料の残部が実質上０.３ｍｍ以下の微粉である
粒度構成を有する混合物を所定の形状に成形し、次いで焼成することを特徴とす
る。
０００９
作用
従来のカルシア安定化ジルコニア原料を使用したジルコニア質れんがの場合、
Ｃａ添加鋼を受鋼すると、ＣａＯ−Ａｌ2Ｏ3系の低融点スラグの浸潤が大きく、
組織の膨潤や浸潤層の剥離が問題となっていた。本発明では、マグネシア安定化
ジルコニア及び／またはマグネシア部分安定化ジルコニアを使用することにより
、ＣａＯ−Ａｌ2Ｏ3系のスラグの浸潤を抑制することが可能になった。ＣａＯ−
Ａｌ2Ｏ3系スラグがマグネシア安定化ジルコニアと接することにより、スラグ中
のＣａＯ成分がジルコニア中に固溶し、それと置換してジルコニア中のＭｇＯが
排出される。排出されたＭｇＯ成分はスラグ中のＡｌ2Ｏ3成分と反応し、ＭｇＯ
・Ａｌ2Ｏ3スピネルを粒界に形成する。その結果、侵入してきた低融点のＣａＯ
−Ａｌ2Ｏ3系スラグはジルコニア質れんが表面で分解吸収される。そのときに粒
界の空隙に生成するＭｇＯ・Ａｌ2Ｏ3スピネルは融点約２１３５℃にあり、組織
を緻密化し、より浸潤し難い保護層を形成するという効果がある。
００１０
本発明に使用するマグネシア安定化ジルコニアまたはマグネシア部分安定化ジ
ルコニア原料としては、少なくとも２重量％以上のＭｇＯを含有していなければ
、上記スラグ浸潤防止効果が得られず、６重量％を超えてもその効果は変化しな
い。
００１１
一方、マグネシア安定化ジルコニアまたはマグネシア部分安定化ジルコニア原
料単味の使用では、ジルコニアれんがの熱膨張が大きく、耐スポール性が低下し
てしまうという欠点があった。そこで本発明では、熱膨張率の低い未安定化ジル
コニア原料とマグネシア安定化ジルコニアまたはマグネシア部分安定化ジルコニ
ア原料を組み合わせることにより、熱膨張を低減すると共に焼成中にマイクロク
ラックを生成させ、熱衝撃抵抗性を向上させた。未安定化ジルコニア原料の配合
比率は１０重量％未満では、耐熱衝撃性改善効果が得られず、５０重量％を超え
ると未安定化ジルコニアの１０００℃付近での単斜晶←→正方晶への転移膨張の
影響が大きくなり、逆に耐熱衝撃性が低下するので、未安定化ジルコニア原料の
配合量は１０〜５０重量％の範囲内が好ましい。また、未安定化ジルコニア原料
はＺｒＯ2として９５重量％以上の純度を有するものが好ましい。
００１２
本発明に使用されるマグネシア安定化ジルコニアまたはマグネシア部分安定化
ジルコニア原料の粒度は１.４〜０.３ｍｍの粗粒を含み、残部が実質上０.３ｍ
ｍ未満の微粉からなる。マグネシア安定化ジルコニアまたはマグネシア部分安定
化ジルコニア原料が全て０.３ｍｍ未満の微粉から構成された場合には、耐熱衝
撃性が不充分であり、また、スラグ浸潤層またはスラグ反応層の緻密化が急激に
進行し、反応層と未変質部との間に大きな組織ギャップが発生し、剥離が発生し
易いという欠点があった。
００１３
本発明では、１.４〜０.３ｍｍのマグネシア安定化ジルコニアまたはマグネシ
ア部分安定化ジルコニア原料の粗粒をマグネシア安定化ジルコニアまたはマグネ
シア部分安定化ジルコニア原料と未安定化ジルコニア原料の合計量を基準として
１０〜４０重量％使用することにより、耐熱衝撃性を向上させると共にスラグ反
応層の急激な緻密化を抑制し、反応層の剥離を防止することが可能になった。マ
グネシア安定化ジルコニアまたはマグネシア部分安定化ジルコニア原料の粗粒が
１０重量％未満では反応層の剥離防止効果が少なく、４０重量％を超えると緻密
な組織が得られず、強度が低下してしまう。
００１４
本発明の製造方法によるジルコニア質れんがは、上述の粒度調整したジルコニ
ア原料を所定割合で配合し、パルプ廃液、糖蜜、リグニンスルホン酸、水などの
結合剤１〜１０％と共に混練して所定の形状に成形し、１５００〜１８００℃で
焼成することにより得られる。また、必要に応じ、焼結助剤としてアルミナの超
微粉を１〜２％添加しても良い。
００１５
本発明に使用される原料としては、電融マグネシア安定化ジルコニア、電融マ
グネシア部分安定化ジルコニア、電融単斜晶ジルコニア、バデライトサンド等を
挙げることができる。
００１６
実施例
実施例１
表１に、ＭｇＯを５重量％含有するマグネシア安定化ジルコニア(ＺｒＯ2９４
重量％、その他１重量％)を使用した場合の実施例を示す。
表１に示す所定の配合物を結合剤と共にウェットパンで混練したものを、フリ
クションプレスにて、２００×３００×３０ｍｍのプレート状に成形し、乾燥後
１７５０℃で成形して供試試料とした。表中、本発明製造方法に係る製品を本発
明品と呼称する。後記表２においても同じ。
００１７
【表１】
００１８
表１中の比較品１では、ＣａＯ４重量％のカルシア安定化ジルコニアを使用し
た。また、未安定化ジルコニアとしては、ＺｒＯ2９８重量％のジルコニアを使
用した。侵食、浸潤深さは比較例５を１００とした。
００１９
実施例２
表２には、ＭｇＯを２.５重量％含有するマグネシア部分安定化ジルコニア(Ｚ
ｒＯ2９６重量％、その他１.５重量％)を使用した場合の実施例を示す。
００２０
【表２】
００２１
参考例１
本発明品３を、Ａ製鉄所タンディッシュスライドバルブのプレートに適用した
結果、従来の未安定化ジルコニアを主体とする微粉構成のジルコニア質プレート
に比較し、亀裂が少なく、エッジ欠けが約１／３に減少し、プレートの寿命が約
１.５倍向上した。
００２２
参考例２
本発明品１を、Ｂ製鉄所ビレットＣＣ用タンディッシュノズルに適用した結果
、従来のカルシア安定化ジルコニアを主体としたジルコニアノズルに比較し、ス
ラグの浸潤深さが約１／２に減少し、ノズルの孔径拡大速度が２／３に減少し、
鋳造操業が著しく安定した。
００２３
発明の効果
本発明の製造方法に係るジルコニア質れんがでは、マグネシア安定化ジルコニ
ア及び／またはマグネシア部分安定化ジルコニア原料を使用することにより、Ｃ
ａ添加鋼を受鋼する際に、従来のカルシア安定化ジルコニア原料を使用したジル
コニア質れんがの場合に問題となっていたＣａＯ−Ａｌ2Ｏ3系の低融点スラグの
浸潤を抑制することが可能となり、溶鋼の連続鋳造用タンディッシュノズルまた
は溶鋼の流量コントロール用のプレートれんがに適した材質を提供することがで
きる。BACKGROUND OF THE INVENTION FIELD The present invention on the 0001 Industrial to a method for producing zirconia Ren is suitable for plate brick for molten steel in continuous casting tundish nozzle or the molten steel flow control. [0002] In continuous casting of molten steel, the nozzle holes of tundish nozzles and plate bricks are subjected to chemical erosion due to components in the molten steel in addition to abrasion due to the flow of the molten steel, so that dense zirconia refractories are used. I have. [0003] For example, Japanese Patent Application Laid-Open No. 53-94311 discloses a method of granulating particles of 74 μm or less.
A method for producing a dense refractory material having a porosity of 10% or less from secondary particles is disclosed.
JP-A-61-21968 discloses that naturally occurring badelite sand and a stabilizer are used in an amount of 0.3.
There is disclosed a method for producing a zirconia refractory for a tundish nozzle, which comprises mixing and pulverizing to a thickness of about 0.01 mm, granulating, forming and firing. [0004] In addition, a tundish nozzle having a porosity of 20% or more obtained by kneading, forming, and firing a zirconia raw material stabilized by calcia as a continuous particle size from coarse particles to fine powder by a conventional method is generally used. Problems to be Solved by the Invention Zirconia bricks containing coarse particles of calcia-stabilized zirconia and having a porosity of 20% are relatively excellent in spall resistance, and are difficult to crack when they are large in size or have large nozzle holes. Although it has advantages, when it is subjected to Ca-added steel, high oxygen steel, etc., the slag infiltrates greatly, forms a thick altered layer, and is greatly damaged by peeling and erosion from the surface due to structural spalling. . [0006] Dense zirconia brick consisting only of fine powder of 0.3 mm or less has high strength and high corrosion resistance, but has a defect of poor thermal shock resistance. In the case of a large shape or a large nozzle hole, it is easily broken. Also, the edge portion is likely to be missing. Further, the brick having such a fine powder composition has poor moldability, requires a granulation treatment, and has a large shrinkage during firing, so that it has been difficult to produce a large-sized product. [0007] Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a zirconia brick suitable for a tundish nozzle for continuous casting of molten steel or a plate brick for flow control of molten steel, which is excellent in corrosion resistance and thermal shock resistance. It is to provide a manufacturing method of. [0008] Accordingly, a method for producing a zirconia brick according to the present invention comprises a magnesia-stabilized zirconia and / or a partially magnesia-stabilized zirconia having an MgO content of 2 to 6% by weight and a balance substantially consisting of zirconia. raw materials 50-90%, and 95 wt% as ZrO 2 or more non-stabilized zirconia raw material purity and also contains 10 to 50 wt%, and the magnesia stabilized zirconia and / or magnesia partially stabilized zirconia material 10 to 40% by weight (based on the total amount of the magnesia-stabilized zirconia and / or the partially stabilized zirconia raw material and the unstabilized zirconia raw material) has a particle size of 1.4 to 0.3 mm and has a magnesia-stabilized zirconia and / or Alternatively, the remainder of the magnesia partially stabilized zirconia raw material is substantially 0.3 mm or less. It is characterized in that a mixture having a particle size configuration as fine powder is formed into a predetermined shape and then fired. [0009] In the case of zirconia brick using conventional calcia-stabilized zirconia raw material,
When受鋼a Ca containing steel, CaO-Al 2 O 3 system infiltration significantly low melting slag,
Swelling of the tissue and detachment of the infiltration layer have been problems. In the present invention, by using a magnesia-stabilized zirconia and / or magnesia partially stabilized zirconia, it has become possible to suppress the infiltration of CaO-Al 2 O 3 based slag. CaO-
When the Al 2 O 3 -based slag comes into contact with the magnesia-stabilized zirconia, the CaO component in the slag dissolves in the zirconia, displaces it, and the MgO in the zirconia is discharged. The discharged MgO component reacts with the Al 2 O 3 component in the slag to form MgO.
Forming Al 2 O 3 spinel at the grain boundaries; As a result, low-melting CaO
-Al 2 O 3 slag is degraded and absorbed by the zirconia brick surface. The MgO.Al 2 O 3 spinel generated in the voids at the grain boundaries at that time has a melting point of about 2135 ° C., and has the effect of densifying the structure and forming a protective layer that is more difficult to infiltrate. If the magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material used in the present invention does not contain at least 2% by weight or more of MgO, the above-mentioned slag infiltration preventing effect cannot be obtained, and more than 6% by weight. The effect does not change. 0011 On the other hand, magnesia-stabilized zirconia or magnesia partially stabilized zirconia original
The use of the raw material alone has the disadvantage that the thermal expansion of the zirconia brick is large and the spall resistance is reduced. Therefore, in the present invention, by combining an unstabilized zirconia raw material having a low coefficient of thermal expansion with a magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material , thermal expansion is reduced, and microcracks are generated during firing, thereby reducing thermal shock resistance. Improved. If the blending ratio of the unstabilized zirconia raw material is less than 10% by weight, the effect of improving thermal shock resistance cannot be obtained, and if it exceeds 50% by weight, the unstabilized zirconia becomes monoclinic at around 1000 ° C. →→ tetragonal. The amount of unstabilized zirconia raw material is preferably in the range of 10 to 50% by weight because the effect of the transition expansion becomes large and the thermal shock resistance is reduced. Further, unstabilized zirconia material <br/> are preferably has a purity of more than 95 wt% as ZrO 2. The particle size of the magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material used in the present invention includes coarse particles of 1.4 to 0.3 mm, and the balance is substantially 0.3 m.
m. When the magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material is all composed of fine powder having a size of less than 0.3 mm, the thermal shock resistance is insufficient and the slag infiltration layer or the slag reaction layer is rapidly densified. And a large tissue gap is generated between the reaction layer and the unaltered portion, and there is a disadvantage that peeling is likely to occur. In the present invention, the coarse particles of the magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material having a size of 1.4 to 0.3 mm are determined based on the total amount of the magnesia-stabilized zirconia or the magnesia partially stabilized zirconia raw material and the unstabilized zirconia raw material. By using 10 to 40% by weight, it is possible to improve the thermal shock resistance, suppress the rapid densification of the slag reaction layer, and prevent peeling of the reaction layer. If the magnesia-stabilized zirconia or magnesia-partially stabilized zirconia raw material has less than 10% by weight of coarse particles, the effect of preventing the reaction layer from peeling off is small, and if it exceeds 40% by weight, a dense structure cannot be obtained and the strength is reduced. [0014] The zirconia brick produced by the production method of the present invention is obtained by mixing the above-mentioned zirconia raw material having the adjusted particle size at a predetermined ratio, kneading the mixture with 1 to 10% of a binder such as pulp waste liquor, molasses, lignin sulfonic acid, water and the like. It is obtained by molding into a shape and firing at 1500 to 1800 ° C. If necessary, 1 to 2% of ultrafine alumina powder may be added as a sintering aid. Examples of the raw material used in the present invention include electrofused magnesia stabilized zirconia, electrofused magnesia partially stabilized zirconia, electrofused monoclinic zirconia, and baddelite sand. Examples Example 1 Table 1 shows that magnesia-stabilized zirconia (ZrO 2 94) containing 5% by weight of MgO.
%), And 1% by weight). A mixture prepared by kneading a predetermined composition shown in Table 1 together with a binder in a wet pan was formed into a 200 × 300 × 30 mm plate by a friction press, dried, and then formed at 1750 ° C. to obtain a test sample. . In the table, the products related to the manufacturing method of the present invention
It is called a bright product. The same applies to Table 2 below . [Table 1] In Comparative product 1 in Table 1, calcia-stabilized zirconia with 4% by weight of CaO was used. Further, as the unstabilized zirconia, zirconia of 98% by weight of ZrO 2 was used. The erosion and infiltration depth was set to 100 in Comparative Example 5. Example 2 Table 2 shows that magnesia partially stabilized zirconia containing 2.5% by weight of MgO (Z
An example in which rO 2 ( 96% by weight, other 1.5% by weight) is used will be described. [Table 2] REFERENCE EXAMPLE 1 As a result of applying the product 3 of the present invention to a plate of a tundish slide valve of an A steelworks, compared with a conventional zirconia-based plate mainly composed of unstabilized zirconia, it has fewer cracks and chipped edges. Was reduced to about 1/3, and the life of the plate was improved by about 1.5 times. REFERENCE EXAMPLE 2 As a result of applying the product 1 of the present invention to a tundish nozzle for billet CC at a steel mill B, the slag infiltration depth was about 1/2 compared to a conventional zirconia nozzle mainly composed of calcia-stabilized zirconia. And the rate of expanding the diameter of the nozzle decreases to 2/3,
The casting operation became remarkably stable. Effect of the Invention In the zirconia brick according to the production method of the present invention, by using magnesia-stabilized zirconia and / or magnesia-partially stabilized zirconia raw material, C
When受鋼the a-added steel, it is possible to suppress the infiltration of conventional calcia CaO-Al 2 has been a problem for zirconia bricks using stabilized zirconia material O 3 based low-melting slag Thus, a material suitable for a tundish nozzle for continuous casting of molten steel or a plate brick for controlling a flow rate of molten steel can be provided.
Claims (1)
るマグネシア安定化ジルコニア及び／またはマグネシア部分安定化ジルコニア原
料を５０〜９０重量％、及びＺｒＯ2として９５重量％以上の純度の未安定化ジ
ルコニア原料を１０〜５０重量％含有してなり、且つ該マグネシア安定化ジルコ
ニア及び／またはマグネシア部分安定化ジルコニア原料の１０〜４０重量％（マ
グネシア安定化ジルコニア及び／またはマグネシア部分安定化ジルコニア原料と
未安定化ジルコニア原料の合計量を基準として）が粒度１.４〜０.３ｍｍで、マ
グネシア安定化ジルコニア及び／またはマグネシア部分安定化ジルコニア原料の
残部が実質上０.３ｍｍ以下の微粉である粒度構成を有する混合物を所定の形状
に成形し、次いで焼成することを特徴とするジルコニア質れんがの製造方法。 Claims 1. A magnesia-stabilized zirconia and / or magnesia-partially stabilized zirconia raw material having an MgO content of 2 to 6% by weight and a balance substantially consisting of zirconia, and ZrO. 2) 10 to 50% by weight of an unstabilized zirconia raw material having a purity of 95% by weight or more, and 10 to 40% by weight of the magnesia stabilized zirconia and / or magnesia partially stabilized zirconia raw material (magnesia stabilized The zirconia and / or magnesia partially stabilized zirconia raw material and the unstabilized zirconia raw material have a particle size of 1.4 to 0.3 mm, and the remainder of the magnesia stabilized zirconia and / or magnesia partially stabilized zirconia raw material is A mixture having a particle size composition that is substantially fine powder of 0.3 mm or less is formed into a predetermined shape. And then calcining the zirconia brick.
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