JP2005139040A - Graphite-containing brick - Google Patents
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- JP2005139040A JP2005139040A JP2003378250A JP2003378250A JP2005139040A JP 2005139040 A JP2005139040 A JP 2005139040A JP 2003378250 A JP2003378250 A JP 2003378250A JP 2003378250 A JP2003378250 A JP 2003378250A JP 2005139040 A JP2005139040 A JP 2005139040A
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Abstract
Description
本発明は、酸化環境下での耐食性と耐スポール性の両特性に優れる黒鉛含有煉瓦に関するものである。 The present invention relates to a graphite-containing brick excellent in both corrosion resistance and spall resistance in an oxidizing environment.
黒鉛含有煉瓦は、耐スラグ浸透性に優れ、高熱伝導性と低熱膨張牲とに由来する耐スポール性に優れるという理由で、製鉄プロセス等の分野において広く（例えば、高炉樋や混銑車、溶銑鍋、転炉、ＲＨ脱ガス装置、連鋳ノズルなどの分野）に使用されている。 Graphite-containing bricks are widely used in fields such as iron making processes because they have excellent slag penetration resistance and excellent spall resistance due to their high thermal conductivity and low thermal expansion (for example, blast furnace steel, kneading cars, hot metal ladle). , Converters, RH degassing devices, continuous casting nozzles, etc.).
ところが、黒鉛含有煉瓦は、酸化されやすい環境で使用すると、その黒鉛が酸化されるために耐用性が著しく低下するという問題があった。その黒鉛の酸化は、気相中のＯ2またはＣＯやスラグ中のFeＯ、あるいは耐火物中のMgＯやSiＯ2によって引き起こされるものである。その防止のため、従来、Al、Mg、Si、Ｂ4Ｃなどの金属や炭化物などの酸化防止剤が用いられている（特許文献１参照）。この従来技術の特徴は、耐火物中の黒鉛に優先して酸化される酸化防止剤を用いること、および酸化生成物にて酸化性気体の流通経路を閉塞することにより、黒鉛の酸化を抑制することにある。しかし、この従来技術による黒鉛の酸化抑制剤の効果は限定的で、黒鉛の酸化を完全に防止することはできない。 However, when the graphite-containing brick is used in an environment where it is easily oxidized, the graphite is oxidized, so that the durability is remarkably lowered. The oxidation of the graphite is caused by O 2 or CO in the gas phase, FeO in the slag, or MgO or SiO 2 in the refractory. Because of its anti-conventional, Al, Mg, Si, antioxidants such as metal or carbides, such as B 4 C is used (see Patent Document 1). The feature of this prior art is that the oxidation of graphite is suppressed by using an antioxidant that is preferentially oxidized over the graphite in the refractory, and by closing the flow path of the oxidizing gas with the oxidation product. There is. However, the effect of the graphite oxidation inhibitor according to this prior art is limited, and the oxidation of graphite cannot be completely prevented.
上述したように、従来技術は、黒鉛の酸化を防止できないことから、どうしてもその黒鉛が酸化してしまい、ＣＯガスとして揮散するために耐火物の耐食性が著しく劣化するという問題があった。即ち、酸化しやすい環境ではむしろ、黒鉛含有量の低い煉瓦の方が、優れた耐食性を示すことが知られている。
しかしながら、黒鉛含有煉瓦中の黒鉛含有量が少なくなると、逆に、耐スポール性が劣化するという新らたな問題が生じた。
つまり、従来の黒鉛含有煉瓦については、酸化環境下において使用した場合でもなお、耐食性と耐スポール性の両方の特性に優れるものはなかった。
However, when the graphite content in the graphite-containing brick decreases, a new problem arises that, on the contrary, the spall resistance deteriorates.
That is, none of the conventional graphite-containing bricks is excellent in both corrosion resistance and spall resistance even when used in an oxidizing environment.
上述したように、従来の一般的な黒鉛含有煉瓦の場合、酸化されやすい環境で使用すると、耐食性か、耐スポール性のいずれかが犠牲になるという致命的な欠陥があった。
そこで、本発明では、酸化環境において用いても、耐食性と耐スポール性との両方の特性に優れる黒鉛含有煉瓦を提供することを目的とする。
As described above, in the case of a conventional general graphite-containing brick, there is a fatal defect that either corrosion resistance or spall resistance is sacrificed when used in an environment that is easily oxidized.
Therefore, an object of the present invention is to provide a graphite-containing brick that is excellent in both corrosion resistance and spall resistance even when used in an oxidizing environment.
上記目的を実現するために鋭意研究した結果、発明者らは、上述した２つの特性（耐食性、耐スポール性）がともに優れた黒鉛含有煉瓦を得るには、その煉瓦中の黒鉛分を供給する手段として、耐酸化性と耐食性の付与に有効な低黒鉛含有量の耐火物と耐スポール性の付与に有効な高黒鉛含有量の耐火物とを組み合わせたものを用いることが有効であることを突き止めた。 As a result of diligent research to achieve the above object, the inventors supply the graphite content in the brick in order to obtain a graphite-containing brick excellent in both of the above-described two characteristics (corrosion resistance and spall resistance). As a means, it is effective to use a combination of a low graphite content refractory effective for imparting oxidation resistance and corrosion resistance and a high graphite content refractory effective for imparting spall resistance. I found it.
即ち、本発明は、黒鉛を３〜30 mass％含有する黒鉛含有煉瓦において、黒鉛含有率が５〜50 mass％で残部が耐火性骨材からなる黒鉛含有耐火物を造粒して平均粒径１〜40 mmの黒鉛含有造粒物を35〜65質量部と、耐火物原料及び黒鉛を含み黒鉛含有率が前記黒鉛含有造粒物の黒鉛含有率よりも小さい黒鉛含有粉状原料を65〜35質量部とを、混合、成形してなることを特徴とする黒鉛含有煉瓦である。 That is, in the present invention, a graphite-containing brick containing 3 to 30 mass% of graphite is granulated from a graphite-containing refractory material having a graphite content of 5 to 50 mass% and the balance of a refractory aggregate. 35 to 65 parts by mass of 1 to 40 mm of graphite-containing granulated material, 65 to 65% of graphite-containing powdery material containing a refractory material and graphite and having a graphite content smaller than the graphite content of the graphite-containing granulated material A graphite-containing brick characterized by mixing and molding 35 parts by mass.
本発明に係る黒鉛含有煉瓦では、耐スポール性に優れる黒鉛含有造粒物の表面を、その黒鉛含有造粒物よりも、黒鉛含有率が小さい黒鉛含有粉状原料で被覆した形態としているため、煉瓦内に黒鉛を均質に分散させる従来の黒鉛含有煉瓦と比較して、同じ黒鉛含有率であっても、煉瓦表面で酸化雰囲気に露出される黒鉛を相対的に低減させることができ、このことによって、耐酸化性と耐食性を向上させることができる。また、黒鉛含有煉瓦中の黒鉛含有造粒物はその高熱伝導性、低熱膨張性により、黒鉛含有煉瓦の耐スポール性を向上させる。この相乗効果によって、本発明に係る黒鉛含有煉瓦は、同じ黒鉛含有率の煉瓦に対して、耐酸化性、耐食性と耐スポール性を共に向上した性能を発揮することができる。 In the graphite-containing brick according to the present invention, because the surface of the graphite-containing granule excellent in spall resistance is covered with a graphite-containing powdery raw material having a lower graphite content than the graphite-containing granule, Compared to conventional graphite-containing bricks that uniformly disperse graphite in the brick, even if the graphite content is the same, the graphite exposed to the oxidizing atmosphere on the brick surface can be relatively reduced. Therefore, oxidation resistance and corrosion resistance can be improved. Further, the graphite-containing granulated material in the graphite-containing brick improves the spall resistance of the graphite-containing brick due to its high thermal conductivity and low thermal expansion. Due to this synergistic effect, the graphite-containing brick according to the present invention can exhibit the performance of improving both oxidation resistance, corrosion resistance and spall resistance with respect to the brick having the same graphite content.
本発明に係る黒鉛含有煉瓦は、耐酸化性と耐食性に優れる低黒鉛含有率の黒鉛含有粉状原料の中に、耐スポール性に優れる高黒鉛含有率の黒鉛含有造粒物を分散させてなるものであって、酸化環境での耐食性と耐スポール性の両方の特性に優れるという特徴がある。 The graphite-containing brick according to the present invention is obtained by dispersing a graphite-containing granulated material having a high graphite content excellent in spall resistance in a low graphite content powder-containing raw material excellent in oxidation resistance and corrosion resistance. It is characterized by excellent properties in both corrosion resistance and spall resistance in an oxidizing environment.
本発明の黒鉛含有煉瓦は黒鉛成分として、第１に、耐スポール性を付与するために黒鉛含有造粒物を配合することが必要である。その黒鉛含有造粒物は、黒鉛を５〜50 mass％含有し残部が耐火性骨材からなるものである。
この黒鉛含有造粒物は、本発明に係る黒鉛含有煉瓦に、高い耐スポール性を付与するために配合されるものであって、黒鉛含有率を５〜50 mass％の範囲にした理由は、この黒鉛含有造粒物の黒鉛含有率が５mass％を下回ると、耐スポール性改善効果がなくなる。一方、黒鉛含有造粒物中の黒鉛含有率が50 mass％を超えると、黒鉛含有煉瓦中の黒鉛分が黒鉛含有造粒物中に集中して含まれることになり、結果的に黒鉛含有煉瓦全体に占める黒鉛含有造粒物の体積率が低下することになる。そのため、黒鉛含有煉瓦中に黒鉛含有造粒物が疎らに点在することになり、耐スポール性改善の効果が低下する。したがって、前記黒鉛含有造粒物中の黒鉛含有率は、５〜50 mass％の範囲、好ましくは15〜40 mass％とする。
First, the graphite-containing brick of the present invention needs to contain a graphite-containing granulated material as a graphite component in order to impart spall resistance. The graphite-containing granulated product contains 5 to 50 mass% of graphite and the remainder is made of a refractory aggregate.
This graphite-containing granulated product is blended to impart high spall resistance to the graphite-containing brick according to the present invention, and the reason for setting the graphite content in the range of 5 to 50 mass% is as follows. When the graphite content of the graphite-containing granulated product is less than 5 mass%, the effect of improving the spall resistance is lost. On the other hand, if the graphite content in the graphite-containing granule exceeds 50 mass%, the graphite content in the graphite-containing brick is concentrated and contained in the graphite-containing granule. The volume ratio of the graphite-containing granulated material occupying the whole will decrease. Therefore, the graphite-containing granulated material is scattered sparsely in the graphite-containing brick, and the effect of improving the spall resistance is reduced. Therefore, the graphite content in the graphite-containing granulated product is in the range of 5 to 50 mass%, preferably 15 to 40 mass%.
さらに、この黒鉛含有造粒物は、平均粒径が１〜40 mmの範囲の大きさであることが必要である。その理由は、平均粒径の大きさが１mmを下回ると、比表面積が大きくなりすぎるため、後述する黒鉛含有粉状原料による被覆作用、即ち該黒鉛含有造粒物のまわりを包囲してこれを埋没状態にすることで酸素の影響を小さくすることが困難になり、結果的に、黒鉛含有造粒物を造粒せずに使用するのと同じになり、耐スポール性改善効果がなくなる。一方、造粒物の粒径が40 mmを上回る大きさになると、煉瓦全体の均質性が損なわれるので好ましくない。したがって、黒鉛含有造粒物である造粒物は１〜40 mmの範囲、好ましくは２〜40 mmの平均粒径をもつものであることが必要である。
この黒鉛含有造粒物は鱗状黒鉛、薄肉黒鉛、人造黒鉛、土状黒鉛など、耐火物用として用いられる公知の黒鉛と、アルミナ、シリカ、マグネシア、カルシア、ジルコニア、クロミアなどの酸化物や炭化けい素などの炭化物、あるいはそれらの混合物、化合物の一種以上の耐火物骨材を使用することができる。これらの黒鉛、耐火物骨材を混合してブリケットマシン等により圧縮成形することで黒鉛含有造粒物を製造できる。この際、黒鉛と耐火性骨材にさらにバインダーとしてフェノール樹脂等の有機レジン、タールピッチなどを使用することもできる。バインダーを使用する場合には、黒鉛と耐火性骨材の合計量100質量部に対して、10質量部以下のバインダーを添加して混合し圧縮成形した後に、加熱してバインダーを硬化させることが好ましい。
Further, the graphite-containing granulated product needs to have an average particle size in the range of 1 to 40 mm. The reason is that if the average particle size is less than 1 mm, the specific surface area becomes too large, so that the covering action by the graphite-containing powdery material described later, that is, surrounding the graphite-containing granulated material is surrounded by this. By making it buried, it becomes difficult to reduce the influence of oxygen, and as a result, it becomes the same as using a graphite-containing granulated product without granulation, and the effect of improving the spall resistance is lost. On the other hand, when the particle size of the granulated product exceeds 40 mm, the homogeneity of the entire brick is impaired, which is not preferable. Therefore, the granulated product that is a graphite-containing granulated product needs to have an average particle size in the range of 1 to 40 mm, preferably 2 to 40 mm.
This graphite-containing granulated material is known graphite used for refractories such as scale-like graphite, thin-walled graphite, artificial graphite, and earth-like graphite, and oxides and carbides such as alumina, silica, magnesia, calcia, zirconia, and chromia. One or more refractory aggregates of carbides such as elemental elements, mixtures thereof, or compounds can be used. A graphite-containing granulated product can be produced by mixing these graphites and refractory aggregates and compressing them with a briquette machine or the like. At this time, an organic resin such as a phenol resin, tar pitch, or the like can be used as a binder in addition to graphite and refractory aggregate. When using a binder, with respect to 100 parts by mass of the total amount of graphite and refractory aggregate, 10 parts by mass or less of binder may be added and mixed and compression molded, and then heated to cure the binder. preferable.
本発明に係る黒鉛含有煉瓦は、上記黒鉛含有造粒物の他に、この煉瓦に耐酸化性と耐食性を付与するために、この黒鉛含有造粒物よりも黒鉛含有率が相対的に少ない黒鉛含有粉状原料を使用することが必要である。
一般に、黒鉛を含有する耐火物の耐酸化性や耐食性は、黒鉛量に強く依存し、黒鉛含有率の低い方が優れた耐酸化性と耐食性を示すことが知られている。本発明において、このような黒鉛含有率の低い黒鉛含有粉状原料を使う意義は、耐スポール性改善のために加える前記黒鉛含有造粒物の表面を覆うことで、この黒鉛含有造粒物の特性である低耐酸化性、低耐食性部分を酸化環境から遮蔽するためである。即ち、黒鉛含有率の高い黒鉛含有造粒物のもつ欠点を補うためには、その黒鉛含有造粒物よりも黒鉛含有率の少ない、しかも粉状の黒鉛含有粉状原料を用いないと、耐酸化性や耐食性を確実に改善することはできない。
The graphite-containing brick according to the present invention, in addition to the above-mentioned graphite-containing granulated product, has a graphite content relatively lower than that of the graphite-containing granulated product in order to impart oxidation resistance and corrosion resistance to the brick. It is necessary to use the contained powdery raw material.
In general, it is known that the oxidation resistance and corrosion resistance of a refractory containing graphite strongly depend on the amount of graphite, and the lower the graphite content, the better the oxidation resistance and corrosion resistance. In the present invention, the significance of using such a graphite-containing powdery material having a low graphite content is that the surface of the graphite-containing granulated material to be added to improve the spall resistance is covered with the graphite-containing granulated material. This is because the low oxidation resistance and low corrosion resistance portions, which are characteristics, are shielded from the oxidizing environment. In other words, in order to compensate for the disadvantages of graphite-containing granules having a high graphite content, it is necessary to use a powdery graphite-containing raw material having a lower graphite content than that of the graphite-containing granulated material. It is impossible to reliably improve the chemical resistance and corrosion resistance.
したがって、成形した黒鉛含有率の高い前記黒鉛含有造粒物の表面を、粉状の低黒鉛含有率の黒鉛含有粉状原料にて、上述した所定の効果が得られるように被覆することを前提として、この両者の配合量を決定することが必要である。
即ち、黒鉛含有造粒物35〜65質量部に対し、65〜35質量部の黒鉛含有粉状原料を配合する。それは、黒鉛含有造粒物の量が35質量部未満では、黒鉛含有造粒物が疎らに存在することになり、耐スポール性改良効果が損なわれる。一方、65質量部超では、黒鉛含有造粒物を黒鉛含有粉状原料で被覆するのが困難となる。
Therefore, it is assumed that the surface of the molded graphite-containing granulated product having a high graphite content is coated with a powdery low-graphite-containing graphite-containing raw material so as to obtain the predetermined effect described above. Therefore, it is necessary to determine the blending amount of both.
That is, 65 to 35 parts by mass of a graphite-containing powdery raw material is blended with respect to 35 to 65 parts by mass of the graphite-containing granulated product. That is, when the amount of the graphite-containing granulated material is less than 35 parts by mass, the graphite-containing granulated material is sparsely present, and the effect of improving the spall resistance is impaired. On the other hand, if it exceeds 65 parts by mass, it becomes difficult to coat the graphite-containing granulated material with the graphite-containing powdery raw material.
本発明に係る黒鉛含有煉瓦は、黒鉛分は、上述したように、黒鉛含有造粒物と黒鉛含有粉状原料との混合物によって構成されている。そして、煉瓦中に占める総黒鉛の含有量は３〜30 mass％である。このように限定する理由は、その黒鉛量が３mass％を下回ると耐スポール性改善効果がなく、一方、黒鉛量が30 mass％を超えると、黒鉛添加による耐スポール性改善効果が飽和するばかりでなく、酸化による耐食性劣化が著しくなるからである。 As described above, the graphite-containing brick according to the present invention is composed of a mixture of a graphite-containing granulated material and a graphite-containing powdery raw material. And the content of the total graphite which occupies in a brick is 3-30 mass%. The reason for this limitation is that when the amount of graphite is less than 3 mass%, there is no effect of improving the spall resistance. On the other hand, when the amount of graphite exceeds 30 mass%, the effect of improving the spall resistance is not only saturated. This is because the corrosion resistance deterioration due to oxidation becomes remarkable.
以上、本発明の特徴的な構成部分について説明したが、煉瓦の成形に当たっては、上述した黒鉛含有造粒物と黒鉛含有粉状原料の他、公知のバインダー等を混合して製造することができる。バインダーとして樹脂バインダーを用いる場合には、150〜250℃程度で硬化させる。また、タールピッチなどを添加する場合は、還元雰囲気中で焼成して炭素結合させる方法が好ましい。 As described above, the characteristic constituent parts of the present invention have been described. However, in forming a brick, a known binder or the like can be mixed and manufactured in addition to the above-mentioned graphite-containing granulated material and graphite-containing powdery raw material. . When a resin binder is used as the binder, it is cured at about 150 to 250 ° C. Moreover, when adding tar pitch etc., the method of baking in a reducing atmosphere and making it carbon bond is preferable.
上記の黒鉛含有造粒物、黒鉛含有粉状原料における耐火性能を示す耐火物原料としては、アルミナやシリカ、マグネシア、カルシア，ジルコニア、クロミアなどの酸化物、炭化けい素などの炭化物やそれらの混合物、化合物の１種以上を使用することができる。これらの原料は、天然鉱物、電融品、焼成品、仮焼品などのいずれもが使用可能であり、基本的には0．00１〜10 mm程度の粒径のものが好ましい。 Examples of the refractory material showing the fire resistance performance in the above graphite-containing granulated material and graphite-containing powdery material include oxides such as alumina, silica, magnesia, calcia, zirconia, and chromia, carbides such as silicon carbide, and mixtures thereof. One or more of the compounds can be used. As these raw materials, any of natural minerals, electrofused products, calcined products, calcined products and the like can be used, and basically those having a particle size of about 0.001 to 10 mm are preferable.
上記煉瓦中に含まれる黒鉛としては、鱗状黒鉛、薄肉黒鉛、人造黒鉛、土状黒鉛の他、耐火物用として用いられる公知の黒鉛も使用できる。また、黒鉛ではないが、カーボンブラックなどの炭素類を添加してもよい。 As the graphite contained in the brick, known graphite used for refractories can be used in addition to scale-like graphite, thin-walled graphite, artificial graphite, and earth-like graphite. Further, although not graphite, carbons such as carbon black may be added.
上記煉瓦中のバインダーとしては、フェノール樹脂など有機レジン、タールピッチなどが使用できる。さらに、酸化防止剤や強度付与のために、Al、Mg、Siなどの単体金属または合金、Ｂ4Ｃなどの炭化物の使用も可能である。 As the binder in the brick, an organic resin such as a phenol resin, tar pitch, or the like can be used. Furthermore, it is also possible to use a single metal or alloy such as Al, Mg, or Si, or a carbide such as B 4 C for the purpose of imparting antioxidant or strength.
耐火物原料としてMgＯあるいはA12Ｏ3を用い、黒鉛として鱗状黒鉛、薄肉黒鉛を用いて、黒鉛含有造粒物および黒鉛含有粉状原料を作成し、これらを混合して本発明の実施例となる黒鉛含有煉瓦を製造した。また同様の原料により本発明の範囲を外れる黒鉛含有煉瓦を製造して比較例とし、耐溶損性、耐スポーリング性の比較を行った。煉瓦の製造方法を以下（１）から（４）に示す。 Using MgO or A1 2 O 3 as the refractory material, and using scaly graphite and thin-walled graphite as the graphite, a graphite-containing granulated material and a graphite-containing powdery material are prepared, and these are mixed to obtain an embodiment of the present invention. A graphite-containing brick was produced. Moreover, the graphite containing brick which remove | deviates from the range of this invention with the same raw material was manufactured, and it was set as the comparative example, and the comparison of a melt-resistance and a spalling resistance was performed. The manufacturing method of brick is shown in (1) to (4) below.
（１）黒鉛含有造粒物：粒径３mm以下のMgＯまたはAl2Ｏ3耐火性骨材に対し、粒径３mm以下の鱗状黒鉛50 mass％と薄肉黒鉛50 mass％とからなる黒鉛と、バインダーとしてフェノール樹脂を５mass％添加して、これらを混合したのちブリケットマシンにて、平均粒径１〜40 mmの所定粒径のブリケット（黒鉛含有造粒物）を作製した。ただし、粒径１mmのブリケットの作製には、0.3 mm以下の原料を使用し、ロール圧縮した後、1.18 mmおよび0.6 mmの篩を使用して分級した。なお、このブリケットについては、180℃で３時間保持し、フェノール樹脂を硬化させた。
（２）黒鉛含有粉状原料：粒径0.01〜５mmのMgＯあるいはA12Ｏ3と黒鉛を混合した。その黒鉛は、鱗状黒鉛50 mass％と薄肉黒鉛50 mass％とを配合したものであり、黒鉛含有粉状原料中の黒鉛含有量は1.5〜24.4 mass％の範囲のものを調整した。
（３）表１に示すように、上記黒鉛含有造粒物０〜70質量部と、黒鉛含有粉状原料30〜100質量部をそれぞれ所定の量で配合し、それぞれ黒鉛含有粉状原料の質量に対してフェノール樹脂を5mass％外掛けで添加して混合した。
（４）その後、混合した原料を150 ＭPaの圧力で並形煉瓦の形状に成形し、さらに、180℃で３時間保持して樹脂を硬化させて、黒鉛含有煉瓦を製造した。いずれの煉瓦も５±１％の範囲の気孔率に収まった。
(1) Graphite-containing granulated material: Graphite composed of 50 mass% of scaly graphite having a particle size of 3 mm or less and 50 mass% of thin-walled graphite with respect to MgO or Al 2 O 3 fireproof aggregate having a particle size of 3 mm or less, and a binder After adding 5 mass% of phenol resin and mixing them, briquette (graphite-containing granulated material) having a predetermined particle size of 1 to 40 mm in average particle size was prepared using a briquette machine. However, for the production of briquettes having a particle diameter of 1 mm, raw materials having a diameter of 0.3 mm or less were used, and after roll compression, classification was performed using 1.18 mm and 0.6 mm sieves. In addition, about this briquette, it hold | maintained at 180 degreeC for 3 hours, and hardened the phenol resin.
(2) Graphite-containing powdery raw material: MgO or A1 2 O 3 having a particle size of 0.01 to 5 mm and graphite were mixed. The graphite was prepared by blending 50 mass% of scaly graphite and 50 mass% of thin graphite, and the graphite content in the graphite-containing powdery raw material was adjusted in the range of 1.5 to 24.4 mass%.
(3) As shown in Table 1, 0 to 70 parts by mass of the above graphite-containing granulated material and 30 to 100 parts by mass of the graphite-containing powdery raw material are blended in predetermined amounts, respectively, and the mass of the graphite-containing powdery raw material, respectively. Phenol resin was added and mixed with 5 mass% outer shell.
(4) Thereafter, the mixed raw material was molded into a parallel brick shape at a pressure of 150 MPa, and further maintained at 180 ° C. for 3 hours to cure the resin, thereby producing a graphite-containing brick. All bricks were within a porosity range of 5 ± 1%.
次に、得られた供給材の黒鉛含有煉瓦について耐スポール性と耐食性を調べ、表１に併記した。
耐スポール性評価は、煉瓦の残存弾性率を測定して評価した。並形煉瓦から40×40×160 mmの角柱試験片を切り出し、コークスブリーズ中1400℃で３時間保持して焼成した煉瓦を試験片とした。この試験片を、アルゴン雰囲気中、1400℃に保持した炉内に投入し、15分間保持したのち、水中に投入し、熱衝撃を与えた。熱衝撃前後の試験片について、弾性率を測定し、熱衝撃前の弾性率に対する熱衝撃後の弾性率（以下、これを「残存弾性率」と呼ぶ）を百分率で表し、耐スポール性を評価した。熱衝撃によって内部亀裂が発生すると弾性率が低下するので、該残存弾性率の百分率が100に近いほど、耐スポール性に優れるものである。
Next, the graphite-containing bricks of the obtained supply materials were examined for spall resistance and corrosion resistance, and are also shown in Table 1.
The spall resistance was evaluated by measuring the residual elastic modulus of the brick. A 40 × 40 × 160 mm prism test piece was cut out from the parallel brick, and the brick was fired by holding it at 1400 ° C. for 3 hours in a coke breeze. This test piece was put in a furnace maintained at 1400 ° C. in an argon atmosphere, held for 15 minutes, and then put in water to give a thermal shock. Measure the elastic modulus of the test piece before and after thermal shock, express the elastic modulus after thermal shock relative to the elastic modulus before thermal shock (hereinafter referred to as “residual elastic modulus”) as a percentage, and evaluate the spall resistance did. When an internal crack is generated by thermal shock, the elastic modulus is lowered. Therefore, the closer the percentage of the residual elastic modulus is to 100, the better the spall resistance.
耐食性の評価は、溶損指数を測定して評価した。並形煉瓦より、上底60 mm×下底100 mm×高さ40 mmの台形断面をもつ長さ160 mmの溶損試験片を切り出して使用した。試験片をコークスブリーズ中600℃で３時間保持して仮焼成し、その後、試験片８本で坩堝を組み、電解鉄および塩基度２の転炉スラグを溶解し、1600℃で３時間の溶損試験を行い、試験片の最大溶損部の長さを相対比較して、耐食性の評価とした。なお、この試験では、MgＯ−Ｃ系、Al2Ｏ3−Ｃ系の従来煉瓦における最大溶損部の深さをそれぞれ１００として、これを基準値として、比較対象であるMgＯ−Ｃ系、Al2Ｏ3−Ｃ系それぞれの煉瓦の試験片における最大溶損部の深さを相対値で示したものを溶損指数とする。すなわち溶損指数が小さいほど最大溶損部の深さが小さく、耐食性に優れていることを表す。表１に本発明および比較例の評価結果をまとめた。基準値とするMgＯ−Ｃ系煉瓦は比較例１であり、Al2Ｏ3−Ｃ系煉瓦は比較例７である。 The corrosion resistance was evaluated by measuring the erosion index. A 160 mm long erosion test piece having a trapezoidal cross section with an upper base of 60 mm, a lower base of 100 mm, and a height of 40 mm was cut out from the parallel brick. The test piece was kept in coke breeze at 600 ° C for 3 hours and calcined, then crucible was assembled with 8 test pieces, electrolytic iron and basicity 2 converter slag were melted, and melted at 1600 ° C for 3 hours. A loss test was performed, and the length of the maximum melted portion of the test piece was relatively compared to evaluate the corrosion resistance. In this study, MgO-C-based, Al 2 O 3 -C based conventional maximum erosion portion in the brick depth 100 respectively, as a reference value, MgO-C-based to be compared, Al The melting index is defined as the relative value of the depth of the maximum erosion part in the 2 O 3 -C-based brick specimens. That is, the smaller the erosion index, the smaller the depth of the maximum erosion part and the better the corrosion resistance. Table 1 summarizes the evaluation results of the present invention and comparative examples. The MgO—C brick used as the reference value is Comparative Example 1, and the Al 2 O 3 —C brick is Comparative Example 7.
MgＯ−Ｃ煉瓦として典型的な黒鉛含有量である黒鉛15 mass％の黒鉛含有煉瓦について、黒鉛含有造粒物を含まない従来煉瓦である比較例１と、10 mmの粒径の黒鉛含有造粒物を含む本発明例１〜３を比較する。これらはいずれも黒鉛含有煉瓦としての全黒鉛含有率は15.0 mass％であるが、本発明例１〜３においては、黒鉛含有造粒物を35〜65質量部配合していることにより、比較例１を基準とした溶損指数が約半減しており、顕著に耐食性が向上していることがわかる。残存弾性率は比較例１が80％であるのに対し、76〜81とほぼ同等の性能を示している。すなわち、同じ黒鉛含有量であっても従来煉瓦と比較して同等の耐スポール性を維持しつつ耐食性を大幅に改良できることがわかる。
ここで、本発明例１と同じ黒鉛含有率である黒鉛含有造粒物のブリケットの粒径を１mm、40 mmとして、本発明例１と同じ黒鉛含有造粒物と黒鉛含有粉状原料との配合率で黒鉛含有煉瓦とした本発明例４，５の結果においても、溶損指数、残存弾性率が本発明１とほぼ同等であり、ブリケットの粒径が１〜40 mmの範囲において、本発明の効果を維持できることがわかる。
As for MgO-C brick, a graphite-containing brick having a graphite content of 15 mass%, which is a typical graphite content, is a conventional brick that does not contain a graphite-containing granulated product and Comparative Example 1 that is 10 mm in diameter. Inventive Examples 1 to 3 including the product are compared. In these examples, the total graphite content as a graphite-containing brick is 15.0 mass%, but in Examples 1 to 3 of the present invention, 35 to 65 parts by mass of the graphite-containing granulated material is blended. It can be seen that the melting index based on 1 is approximately halved, and the corrosion resistance is remarkably improved. The residual elastic modulus is 80% in Comparative Example 1, whereas it shows almost the same performance as 76-81. That is, it can be seen that even with the same graphite content, the corrosion resistance can be significantly improved while maintaining the same spall resistance as compared with the conventional brick.
Here, the particle size of the briquette of the graphite-containing granulated product having the same graphite content as in the present invention example 1 is set to 1 mm and 40 mm, and the same graphite-containing granulated product as in the present invention example 1 and the graphite-containing powdery raw material are used. Also in the results of Examples 4 and 5 of the present invention in which the graphite-containing brick was used as a blending ratio, the melting index and the remaining elastic modulus were almost the same as those of the present invention 1, and the briquette particle size was in the range of 1 to 40 mm. It can be seen that the effects of the invention can be maintained.
一方、黒鉛含有造粒物の黒鉛含有率を60 mass％として、全黒鉛量を15 mass％に調整した比較例５では、耐スポール性が低下してしまい好ましくない。さらに、黒鉛含有造粒物の黒鉛含有率を３mass％と低下させた比較例４では、全黒鉛量を３mass％以上に調整することができず、耐スポール性は著しく劣化していて好ましくない。 On the other hand, in Comparative Example 5 in which the graphite content of the graphite-containing granulated product was adjusted to 60 mass% and the total graphite content was adjusted to 15 mass%, the spall resistance was lowered, which is not preferable. Furthermore, in Comparative Example 4 in which the graphite content of the graphite-containing granulated product is reduced to 3 mass%, the total graphite amount cannot be adjusted to 3 mass% or more, and the spall resistance is significantly deteriorated, which is not preferable.
また、黒鉛含有造粒物の黒鉛含有率をそれぞれ５mass％、50 mass％として、黒鉛含有煉瓦の全黒鉛量を３％、30％に調整した本発明例６，７に対して、黒鉛含有造粒物を使用せずに、全黒鉛量を３％、30％に調整した比較例２，３とをそれぞれ比較すると、同じ全黒鉛量であっても、本発明例６，７は残存弾性率を変えることなく、溶損指数を低下させることができている。以上のこと、全黒鉛量が３〜30 mass％の黒鉛含有煉瓦において、黒鉛含有造粒物の黒鉛含有率を５〜50 mass％として配合することで全黒鉛量が同等の従来煉瓦に比べて同等の耐スポール性を維持しつつ耐食性を大幅に改良できることがわかる。
ここで、本発明例６に対して全黒鉛量を2.6 mass％まで低下させたてしまうと、比較例６に示されるように、耐スポール性が著しく損なわれるため好ましくない。
In addition, the graphite-containing granulated product has a graphite content of 5 mass% and 50 mass%, respectively, and the total graphite content of the graphite-containing brick is adjusted to 3% and 30%. Comparing with Comparative Examples 2 and 3 in which the total graphite amount was adjusted to 3% and 30% without using granules, the Examples 6 and 7 of the present invention showed a residual elastic modulus even with the same total graphite amount. Without changing the melting index, the melting index can be lowered. As described above, in graphite-containing bricks with a total graphite content of 3 to 30 mass%, the total graphite content is equivalent to 5-50 mass% by blending the graphite-containing granulated product with a graphite content of 5 to 50 mass%. It can be seen that the corrosion resistance can be greatly improved while maintaining the same spall resistance.
Here, if the total graphite amount is reduced to 2.6 mass% with respect to Inventive Example 6, as shown in Comparative Example 6, the spall resistance is remarkably impaired, which is not preferable.
上述した実施例においては、MgＯ−Ｃ煉瓦を例示して示したが、A12Ｏ3−Ｃ煉瓦についてもまた、耐スポール牲を維持したまま、耐食性を大幅に改良できる（本発明８と比較例７の比較）ことがわかった。 In the above-described embodiment, MgO-C brick is shown as an example, but the corrosion resistance of A1 2 O 3 -C brick can also be greatly improved while maintaining the spall resistance (compared with the present invention 8). Comparison of Example 7)
本発明は耐スラグ浸透性にすぐれ低熱伝導性、低熱膨張性に優れる黒鉛含有煉瓦において、耐スポール性と耐酸化性、耐食性を同時に向上させることができるため、高炉樋、混銑車、溶銑鍋、転炉、ＲＨ脱ガス装置、連鋳ノズル等の製鉄プロセスにおいて広く使用することができる。
The present invention is a graphite-containing brick that has excellent slag penetration resistance, low thermal conductivity, and low thermal expansion, and can simultaneously improve the spall resistance, oxidation resistance, and corrosion resistance. It can be widely used in iron making processes such as converters, RH degassing devices, and continuous casting nozzles.
Claims (1)
In graphite-containing bricks containing 3-30 mass% of graphite, graphite containing a graphite content of 5-50 mass% and the remainder containing granulated graphite-containing refractory consisting of refractory aggregate contains graphite with an average particle size of 1-40 mm 35 to 65 parts by mass of the granulated material and 65 to 35 parts by mass of a graphite-containing powdery material containing a refractory material and graphite and having a graphite content smaller than the graphite content of the graphite-containing granulated material A graphite-containing brick characterized by being molded.
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