JP6826282B2 - Magnesia-Chromium converter How to manufacture steel outlet sleeve bricks - Google Patents
Magnesia-Chromium converter How to manufacture steel outlet sleeve bricks Download PDFInfo
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- 239000011449 brick Substances 0.000 title claims description 86
- 239000011651 chromium Substances 0.000 title claims description 37
- 229910000831 Steel Inorganic materials 0.000 title claims description 36
- 239000010959 steel Substances 0.000 title claims description 36
- 229910052804 chromium Inorganic materials 0.000 title claims description 30
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 33
- 238000005470 impregnation Methods 0.000 claims description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 13
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 claims description 8
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 7
- 238000010304 firing Methods 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 23
- 238000004901 spalling Methods 0.000 description 23
- 230000007797 corrosion Effects 0.000 description 17
- 238000005260 corrosion Methods 0.000 description 17
- 239000000395 magnesium oxide Substances 0.000 description 11
- 238000005299 abrasion Methods 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 230000003628 erosive effect Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- 239000002893 slag Substances 0.000 description 5
- 238000009628 steelmaking Methods 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 239000005011 phenolic resin Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 241001131796 Botaurus stellaris Species 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229920001353 Dextrin Polymers 0.000 description 1
- 239000004375 Dextrin Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- ATRMIFNAYHCLJR-UHFFFAOYSA-N [O].CCC Chemical compound [O].CCC ATRMIFNAYHCLJR-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000000788 chromium alloy Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 210000002808 connective tissue Anatomy 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 235000019425 dextrin Nutrition 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000007849 furan resin Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 235000019794 sodium silicate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006188 syrup Substances 0.000 description 1
- 235000020357 syrup Nutrition 0.000 description 1
- 239000011269 tar Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
本発明は、マグネシア−クロム質煉瓦の製造方法に関し、特に製鋼用転炉の出鋼口スリーブ煉瓦に使用されるマグネシア−クロム質煉瓦の製造方法に関するものである。 The present invention relates to a method for producing magnesia-chromium bricks, and more particularly to a method for producing magnesia-chromium bricks used for steel outlet sleeve bricks of a converter for steelmaking.
製鋼用転炉の出鋼口スリーブは転炉上部に取り付けられている内径80-250mm程度、長さは700-1800mm程度の筒状の煉瓦であり、吹練終了後の鋼を取り鍋に移すための流路となる煉瓦である。出鋼の時間は5-10min程度であり、高温の溶鋼流に曝されることから、耐スポーリング性、耐磨耗性、高強度が要求される。出鋼開始時は、急激な温度上昇に曝されるために耐熱スポーリング性の有する材料が必要である。出鋼中は、高温の溶鋼流に曝され、摩耗や酸化が損傷の主体となる。吹練中は20-50min程度大気雰囲気若しくは出鋼時に付着したスラグに曝されるため、煉瓦にカーボンを含有する場合、当該煉瓦は気相酸化、液相酸化を起こす可能性があり、耐酸化性を強化する必要性がある。 The steel outlet sleeve of the converter for steelmaking is a tubular brick with an inner diameter of about 80-250 mm and a length of about 700-1800 mm attached to the upper part of the converter, and the steel after blowing is transferred to a pan. It is a brick that serves as a flow path for the steel. The steel ejection time is about 5-10 min, and since it is exposed to a high-temperature molten steel stream, spalling resistance, abrasion resistance, and high strength are required. At the start of steel removal, a material with heat-resistant spalling property is required because it is exposed to a rapid temperature rise. During steel ejection, it is exposed to a high temperature molten steel stream, and wear and oxidation are the main causes of damage. During blowing, it is exposed to the air atmosphere for about 20-50 min or the slag that adheres during steel removal. Therefore, if the brick contains carbon, the brick may undergo vapor phase oxidation or liquid phase oxidation, and is oxidation resistant. There is a need to strengthen sex.
このような転炉出鋼口スリーブ煉瓦の材質としては、非特許文献1、非特許文献2に見られるように、過去にはマグネシア−クロム質煉瓦が使用されていた。このマグネシア−クロム質煉瓦は、耐食性、耐酸化性および耐磨耗性に優れた高強度の材質として知られている。しかし耐スポーリング性に劣るため、現在では不焼成マグネシア−カーボン（MgO-C）質煉瓦が主に使用されている。マグネシア−カーボン質煉瓦は耐食性、耐スポーリング性にすぐれた材質として知られている。その一方でマグネシア−クロム質煉瓦に比べて、上記したように耐酸化性、耐磨耗性が大きく劣る材質であることが知られている。不焼成マグネシア−カーボン質煉瓦の耐摩耗性を高めるためには、高温での高強度化をはかる必要があるところから、以下の特許文献に見られる工夫がなされている。 As seen in Non-Patent Document 1 and Non-Patent Document 2, magnesia-chromium bricks have been used as the material for such converter steel mouth sleeve bricks in the past. This magnesia-chromium brick is known as a high-strength material having excellent corrosion resistance, oxidation resistance and abrasion resistance. However, due to its poor spalling resistance, non-fired magnesia-carbon (MgO-C) bricks are now mainly used. Magnesia-carbon brick is known as a material with excellent corrosion resistance and spalling resistance. On the other hand, it is known that the material is significantly inferior in oxidation resistance and abrasion resistance as described above to magnesia-chromium brick. In order to improve the wear resistance of non-fired magnesia-carbon bricks, it is necessary to increase the strength at high temperatures, and therefore, the following patent documents have been devised.
例えば、特許文献１では、溶鋼流による摩耗損傷の改善を目的に樹脂被覆マグネシア粒子とカーボンを含む配合物を成形してなる、製鋼用転炉の出鋼口スリーブ用のマグネシア−カーボン質煉瓦が開示されている。
また、特許文献２では不焼成マグネシア−カーボン質煉瓦にクロム合金鋼ファイバーを含有させ、耐酸化性および耐熱衝撃性を向上させた転炉出鋼口スリーブ用煉瓦が開示されている。
For example, in Patent Document 1, a magnesia-carbon brick for a steel outlet sleeve of a converter for steelmaking, which is formed by molding a compound containing resin-coated magnesia particles and carbon for the purpose of improving wear damage due to molten steel flow. It is disclosed.
Further, Patent Document 2 discloses a brick for a converter outlet sleeve, which contains a chrome alloy steel fiber in a non-fired magnesia-carbon brick to improve oxidation resistance and thermal shock resistance.
更に、特許文献３では耐スポーリング性の改善を目的に、全体がマグネシア−カーボン質煉瓦よりなり、かつ、内周部にアルミナを含有した、製鋼用転炉の出鋼口スリーブ用煉瓦が開示されている。 Further, Patent Document 3 discloses a brick for a steel outlet sleeve of a steelmaking converter, which is entirely made of magnesia-carbonous brick and contains alumina in the inner peripheral portion for the purpose of improving spalling resistance. Has been done.
上記従来技術においては、製鋼用転炉の出鋼口スリーブに用いられるマグネシア−カーボン煉瓦の長寿命化がある程度可能である。しかしながら、より一層の長寿命化を目指そうとするときは以下のような課題がある。 In the above-mentioned conventional technique, it is possible to extend the life of the magnesia-carbon brick used for the steel outlet sleeve of the converter for steelmaking to some extent. However, there are the following problems when aiming for further extension of life.
前記特許文献１の樹脂被覆マグネシア粒子の使用は、600-1000℃の温度域における強度は向上するものの、1000℃以上での熱間の強度改善が不十分である。 The use of the resin-coated magnesia particles of Patent Document 1 improves the strength in the temperature range of 600 to 1000 ° C., but the improvement of the hot strength at 1000 ° C. or higher is insufficient.
また、前記特許文献２に開示するクロム合金鋼ファイバーを含有させたマグネシア−カーボン煉瓦は、ファイバー含有量を増加させると組織の緻密さが失われ、それにともなって、十分な強度が得られない欠点がある。 Further, the magnesia-carbon brick containing a chromium alloy steel fiber disclosed in Patent Document 2 has a drawback that when the fiber content is increased, the fineness of the structure is lost, and as a result, sufficient strength cannot be obtained. There is.
さらに、特許文献３に開示するように、内周部にアルミナを含有したマグネシア−カーボン煉瓦は、転炉用スラグに対する耐食性に劣る傾向がある。 Further, as disclosed in Patent Document 3, magnesia-carbon bricks containing alumina in the inner peripheral portion tend to be inferior in corrosion resistance to converter slag.
本発明は、マグネシア−カーボン質煉瓦に近い耐スポーリング性を維持しつつ、更なる長寿命化できるマグネシア−クロム質煉瓦を得ることを目的とする。 An object of the present invention is to obtain a magnesia-chromium brick that can have a longer life while maintaining a spalling resistance close to that of a magnesia-carbon brick.
本発明は、焼成マグネシア−クロム質煉瓦にピッチを含浸したマグネシア−クロム質煉瓦の製造方法である。 The present invention is a method for producing magnesia-chromium bricks obtained by impregnating calcined magnesia-chromium bricks with pitch.
上記焼成マグネシア−クロム質煉瓦は、MgOを25-85質量%、Cr2O3を5-55質量%、Al2O3を1-14質量%、Fe2O3を7-17質量%及び不純物を5質量%未満有する。 The burning magnesia - chrome bricks is a MgO 25-85 wt%, the Cr 2 O 3 5-55 wt%, the Al 2 O 3 1-14 wt%, a Fe 2 O 3 7 -17% by weight and It has less than 5% by mass of impurities.
前記焼成マグネシア−クロム質煉瓦の焼成温度は、1700-1800℃である。 The firing temperature of the fired magnesia-chromium brick is 1700-1800 ° C.
また、ピッチ含浸処理による含浸率が2-8質量%であり、ピッチ含浸処理は、予め100-400℃に予熱したピッチの溶融槽中に、焼成後のマグネシア−クロム質煉瓦を投入し、加圧力10kgf/cm2以上、加圧時間2時間以上の処理を行うことで、前記含浸率を得ることができる。 In addition, the impregnation rate by the pitch impregnation treatment is 2-8% by mass, and in the pitch impregnation treatment, the magnesia-chromium brick after firing is put into a melting tank having a pitch preheated to 100-400 ° C. The impregnation rate can be obtained by performing a treatment with a pressure of 10 kgf / cm 2 or more and a pressurization time of 2 hours or more.
前記ピッチ含浸処理に使用されるピッチはキノリン不溶分5質量%以下、かつ固定炭素量が25質量%以上のものである。 The pitch used in the pitch impregnation treatment has a quinoline insoluble content of 5% by mass or less and a fixed carbon content of 25% by mass or more.
本発明は、上記したように焼成マグネシア−クロム質煉瓦にピッチを含浸しているので、マグネシア−カーボン質煉瓦に近い耐スポーリング性を維持しつつ、マグネシア−カーボン質煉瓦にはない耐食性、耐酸化性、耐磨耗性を得ることができ、転炉の出鋼口スリーブ用煉瓦として使用したとき長寿命化が期待できる。 In the present invention, since the calcined magnesia-chromic brick is impregnated with pitch as described above, the corrosion resistance and acid resistance that the magnesia-carbon brick does not have while maintaining the spalling resistance close to that of the magnesia-carbon brick. It is possible to obtain chemical resistance and wear resistance, and it can be expected to extend the service life when used as a brick for a steel outlet sleeve of a converter.
＜原理＞
製鋼用転炉の出鋼口スリーブ用の煉瓦の耐スポーリング性向上のために、マグネシアにカーボンを含有せしめたマグネシア−カーボン煉瓦、あるいはカーボン成分としてピッチを含浸せしめたマグネシア−カーボン煉瓦はよく知られている。このようなマグネシア−カーボン質煉瓦は耐スポーリング性には優れているが、耐食性、耐酸化性、耐磨耗性に問題がある。
<Principle>
Magnesia-carbon bricks in which carbon is impregnated in magnesia or magnesia-carbon bricks in which pitch is impregnated as a carbon component are well known in order to improve the spalling resistance of bricks for steel outlet sleeves of converters for steelmaking. Has been done. Such magnesia-carbon bricks are excellent in spalling resistance, but have problems in corrosion resistance, oxidation resistance, and abrasion resistance.
一方、マグネシア−クロム質煉瓦は耐食性、耐磨耗性に優れるが耐スポーリング性に劣る。すなわち、クロミア（Cr2O3）は下記（1）式に示される様に、カーボンによって還元されることが知られており、その温度は約1220℃以上である。 On the other hand, magnesia-chromium bricks are excellent in corrosion resistance and abrasion resistance, but inferior in spalling resistance. That is, it is known that chromium (Cr 2 O 3 ) is reduced by carbon as shown in the following equation (1), and its temperature is about 1220 ° C. or higher.
Cr2O3 + 3C → 2Cr + 3CO （1）
そのため、従来マグネシア−クロム質煉瓦には、上記のようにカーボンを含有せしめたり、あるいはピッチを含浸せしめることは行われなかった。
Cr 2 O 3 + 3C → 2Cr + 3CO (1)
Therefore, conventionally, magnesia-chromic bricks have not been impregnated with carbon or pitch as described above.
しかしながら、マグネシア−クロム質煉瓦の耐スポーリング性を改善できれば耐スポーリング性を備えるとともに、耐食性、耐酸化性、耐磨耗性を備えた出鋼口スリーブ煉瓦を得ることができ、更なる長寿命化が期待できることになる。 However, if the spalling resistance of magnesia-chromium bricks can be improved, it is possible to obtain spawning resistance, corrosion resistance, oxidation resistance, and abrasion resistance, and further lengthening. Life can be expected to be extended.
そこで、出鋼口スリーブでの出鋼状況を観察すると、出鋼時間は長くても10min以内であり、出鋼後のスリーブは次の出鋼まで20-50min待機している状態であるため、この間に煉瓦の温度は低下する。また出鋼口の内孔は転炉スラグによってコーティングされている。そのため、出鋼時の煉瓦の温度はクロミアがカーボンによって還元される温度には達しないか、あるいは、温度に達して還元が起こったとしてもその量は軽微であると考えられる。 Therefore, when observing the steel ejection status at the steel ejection port sleeve, the steel ejection time is within 10 min at the longest, and the sleeve after steel ejection is in a state of waiting for 20-50 min until the next steel ejection. During this time, the temperature of the brick drops. The inner hole of the steel outlet is coated with converter slag. Therefore, it is considered that the temperature of the brick at the time of steel removal does not reach the temperature at which chromia is reduced by carbon, or even if the temperature is reached and reduction occurs, the amount is small.
以上の理由から、マグネシア−クロム質煉瓦にピッチを含浸することで、マグネシア−クロム質煉瓦の耐スポーリング性を高めることができ、高耐用の出鋼口スリーブ用煉瓦得ることが出来ると推定できる。この推定に基づいて、以下に記述するように現実に従来の不焼成マグネシア−カーボン質煉瓦にピッチを含浸して出鋼口スリーブに適用したところ高耐用になることを確認した。 For the above reasons, it can be estimated that by impregnating magnesia-chromium bricks with pitch, the spalling resistance of magnesia-chromium bricks can be improved, and bricks for steel outlet sleeves with high durability can be obtained. .. Based on this estimation, it was confirmed that when a conventional non-fired magnesia-carbon brick was actually impregnated with a pitch and applied to a steel outlet sleeve as described below, it had a high durability.
＜構成および量的範囲＞
本発明は上記のように焼成マグネシア−クロム質煉瓦にピッチを含浸した煉瓦である。
<Composition and quantitative range>
The present invention is a brick obtained by impregnating a calcined magnesia-chromic brick with a pitch as described above.
本発明に適用される焼成マグネシア−クロム質煉瓦のマグネシア（MgO）は全体の25-85質量%とすることが好ましい。MgOが25質量%未満では焼結性が低下し強度が低下するため、耐摩耗性が低下する。また、マグネシアが85質量%以上では耐熱衝撃性や耐スラグ浸潤性が低下する。より好ましくは30-83質量%である。 The magnesia (MgO) of the calcined magnesia-chromic brick applied to the present invention is preferably 25-85% by mass. If MgO is less than 25% by mass, the sinterability is lowered and the strength is lowered, so that the wear resistance is lowered. In addition, when magnesia is 85% by mass or more, heat impact resistance and slag infiltration resistance decrease. More preferably, it is 30-83% by mass.
前記焼成マグネシア−クロム質煉瓦のクロム質にはCr2O3が用いられる。当該Cr2O3は全体の5-55質量%とすることが好ましい。Cr2O3が5質量%未満では耐熱スポーリング性や耐スラグ浸潤性が低下する。また、Cr2O3が55質量%以上では焼結性が低下し強度が低下するため、耐摩耗性が低下する。より好ましくは7-50質量%である。 Cr 2 O 3 is used as the chromium substance of the calcined magnesia-chromium brick. The Cr 2 O 3 is preferably 5-55% by mass of the whole. If Cr 2 O 3 is less than 5% by mass, heat resistance spalling resistance and slag infiltration resistance will decrease. Further, when Cr 2 O 3 is 55% by mass or more, the sinterability is lowered and the strength is lowered, so that the wear resistance is lowered. More preferably, it is 7-50% by mass.
前記焼成マグネシア−クロム質煉瓦には焼結性を高める必要上Al2O3を混入する。当該Al2O3は1-14質量%とすることが好ましい。Al2O3が1質量%未満では焼結性が低下し強度が低下するため、耐摩耗性が低下する。また、Al2O3が14質量%以上では耐食性が低下する。より好ましくは2-12質量%である。 Al 2 O 3 is mixed in the fired magnesia-chromium brick because it is necessary to improve the sinterability. The Al 2 O 3 is preferably 1-14% by mass. If Al 2 O 3 is less than 1% by mass, the sinterability is lowered and the strength is lowered, so that the wear resistance is lowered. Moreover, when Al 2 O 3 is 14% by mass or more, the corrosion resistance is lowered. More preferably, it is 2-12% by mass.
上記Al2O3と同様、焼成マグネシア−クロム質煉瓦の焼結性を高める必要上Fe2O3を混入する。当該Fe2O3は2-17質量%とすることが好ましい。Fe2O3が2質量%未満では焼結性が低下し強度が低下するため、耐摩耗性が低下する。また、Fe2O3が17質量%以上では耐食性が低下する。より好ましくは4-15質量%である。 Similar to the above Al 2 O 3 , Fe 2 O 3 is mixed in because it is necessary to improve the sinterability of the calcined magnesia-chromic brick. The Fe 2 O 3 is preferably 2-17% by mass. If Fe 2 O 3 is less than 2% by mass, the sinterability is lowered and the strength is lowered, so that the wear resistance is lowered. Moreover, when Fe 2 O 3 is 17% by mass or more, the corrosion resistance is lowered. More preferably, it is 4-15% by mass.
前記焼成マグネシア−クロム質煉瓦の不純物成分は上記した成分以外の物質であり、5質量%未満が好ましい。5質量%以上は耐食性が低下する。より好ましくは3質量%未満である。 The impurity component of the calcined magnesia-chromic brick is a substance other than the above-mentioned components, preferably less than 5% by mass. Corrosion resistance decreases when it is 5% by mass or more. More preferably, it is less than 3% by mass.
上記の耐火物原料を混練、焼成して焼成マグネシア−クロム質煉瓦を得ることになる。このときの焼成温度は1650-2000℃が好ましい。焼成温度が1650℃未満では結合組織が未発達であるため、熱間での強度が得られず、耐磨耗性が低下する。また、2000℃以上では焼成中にれんがの変形が起こるなどの問題が発生するため好ましくない。より好ましくは1700-1900℃である。 The above refractory raw materials are kneaded and fired to obtain fired magnesia-chromium bricks. The firing temperature at this time is preferably 1650-2000 ° C. If the firing temperature is less than 1650 ° C., the connective tissue is underdeveloped, so that the strength in hot water cannot be obtained and the abrasion resistance is lowered. Further, if the temperature is 2000 ° C. or higher, problems such as deformation of bricks occur during firing, which is not preferable. More preferably, it is 1700-1900 ° C.
ピッチの含浸率は2-8質量%が好ましい。当該ピッチの含浸率は、含浸後の重量から含浸前の重量を引いた差を含浸前の重量で除した値を質量％として示したものである。ピッチの含浸率が2質量%未満では耐スポーリング性の向上に十分な効果を発揮出来ない。また、れんがの気孔を全て埋めたとしてもピッチ含浸率が8質量％以上となることはないため、含浸率の上限は8質量％とする。 The impregnation rate of the pitch is preferably 2-8% by mass. The impregnation rate of the pitch is the value obtained by dividing the difference obtained by subtracting the weight before impregnation from the weight after impregnation by the weight before impregnation as mass%. If the impregnation rate of the pitch is less than 2% by mass, the effect of improving the spalling resistance cannot be sufficiently exerted. Further, even if all the pores of the brick are filled, the pitch impregnation rate does not exceed 8% by mass, so the upper limit of the impregnation rate is 8% by mass.
前記ピッチ含浸時のピッチの温度は80-420℃が好ましい。ピッチの温度が80℃未満ではピッチが固体の状態で存在するため含浸が出来ない。また、420℃以上ではピッチの炭化が進行し含浸が出来ない。より好ましくは100-400℃である。 The pitch temperature at the time of pitch impregnation is preferably 80-420 ° C. If the pitch temperature is less than 80 ° C, impregnation cannot be performed because the pitch exists in a solid state. Further, at 420 ° C. or higher, carbonization of the pitch progresses and impregnation cannot be performed. More preferably, it is 100-400 ° C.
ピッチ含浸に使用されるピッチの固定炭素量は25質量%以上とすることが好ましい。ここでいう固定炭素量は、JIS K 6910（フェノール樹脂試験方法）中の固定炭素測定法に基づいて測定したものである。固定炭素量が25質量%未満の場合、緻密で強固なカーボンボンドを形成することが出来ないため、耐スポーリング性が向上しない。ここで使用するピッチのキノリン不溶分は5質量%以下とすることが好ましい。当該キノリン不溶分は分子量が1200以上の分子であり、5質量%以上となると気孔へのピッチ含浸が困難となる。 The fixed carbon content of the pitch used for pitch impregnation is preferably 25% by mass or more. The amount of fixed carbon referred to here is measured based on the fixed carbon measurement method in JIS K 6910 (phenol resin test method). When the fixed carbon content is less than 25% by mass, a dense and strong carbon bond cannot be formed, so that the spalling resistance is not improved. The quinoline insoluble content of the pitch used here is preferably 5% by mass or less. The quinoline insoluble matter is a molecule having a molecular weight of 1200 or more, and when it is 5% by mass or more, it becomes difficult to impregnate the pores with pitch.
ピッチ含浸の方法は特に限定されないが、含浸装置に焼成マグネシア−クロム質煉瓦を入れて一旦真空に減圧し、煉瓦中に含まれる空気を排気した後、ピッチを所定時間、所定圧力で含浸することがより好ましい。例えば、真空度100Torr以下に減圧した後、加圧力5kgf/cm2以上にて2時間以上保持する。真空度100Torr以上では、煉瓦内に残留した気泡により、加圧時に煉瓦内部まで均質にピッチを含浸することが出来ない。より好ましくは、真空度60Torr以下である。また、前記加圧時に圧力は5kgf/cm2以上であり、時間は2時間以上である。加圧力が5kgf/cm2未満で保持時間が2時間より短くなった場合では、煉瓦内に有機物を十分に含浸することができない。より好ましくは、加圧力10kgf/cm2以上、加圧時間4時間以上である。これら含浸条件を満たすことにより煉瓦内にピッチが均質に充填され、上述の効果により煉瓦材質の耐スポーリング性が向上する。 The method of pitch impregnation is not particularly limited, but the pitch is impregnated with a predetermined pressure for a predetermined time after the calcined magnesia-chromic brick is placed in the impregnation device and the pressure is once reduced to a vacuum to exhaust the air contained in the brick. Is more preferable. For example, after depressurizing to a vacuum degree of 100 Torr or less, the pressure is maintained at 5 kgf / cm 2 or more for 2 hours or more. When the vacuum degree is 100 Torr or more, the air bubbles remaining in the brick make it impossible to uniformly impregnate the inside of the brick with the pitch during pressurization. More preferably, the degree of vacuum is 60 Torr or less. Further, at the time of the pressurization, the pressure is 5 kgf / cm 2 or more, and the time is 2 hours or more. If the pressing force is less than 5 kgf / cm 2 and the holding time is shorter than 2 hours, the bricks cannot be sufficiently impregnated with organic matter. More preferably, the pressing force is 10 kgf / cm 2 or more and the pressurizing time is 4 hours or more. By satisfying these impregnation conditions, the pitch is uniformly filled in the brick, and the spalling resistance of the brick material is improved by the above-mentioned effect.
本発明に用いるクロミア原料は、前述の組成を満たすものであれば限定されないが例えばクロム鉄鉱、焼結品、電融品が使用される。 The chromia raw material used in the present invention is not limited as long as it satisfies the above-mentioned composition, and for example, chromite, a sintered product, and an electric fusion product are used.
本発明に用いるマグネシア原料、アルミナ原料は、前述の組成を満たすものであれば限定されないが例えば焼結品、電融品が使用される。 The magnesia raw material and alumina raw material used in the present invention are not limited as long as they satisfy the above-mentioned composition, and for example, a sintered product and an electrolytic product are used.
本発明に用いる酸化鉄は、前述の組成を満たすものであれば限定されないが例えばミルスケール、合成原料が使用される。 The iron oxide used in the present invention is not limited as long as it satisfies the above-mentioned composition, but for example, mill scale and synthetic raw materials are used.
また、本発明に使用する結合材はフラン樹脂やフェノール樹脂、デキストリン、シリコーン樹脂、ポリビニルアルコール、タール、ピッチ、糖蜜、珪酸ソーダ、珪酸カリウム、苦汁、硫酸マグネシウムからなる群から選択される1種または2種以上である。ここで、結合材の配合量は、前記マグネシア原料、クロミア原料、酸化鉄やアルミナ原料からなる配合物100質量%に対して、外掛けで1-10質量%である。結合材の配合が1質量%未満であると、結合材の添加効果がなく、成形体を維持できないために好ましくない。また結合材の量が10質量%を超えると成形体の焼成時にラミネーションを起こし製品歩留まりが極度に悪化する。より好ましくは2-7質量%の範囲である。 The binder used in the present invention is one selected from the group consisting of furan resin, phenol resin, dextrin, silicone resin, polyvinyl alcohol, tar, pitch, syrup, sodium silicate, potassium silicate, bittern, and magnesium sulfate. There are two or more types. Here, the blending amount of the binder is 1-10% by mass on the outside with respect to 100% by mass of the blend composed of the magnesia raw material, the chromia raw material, the iron oxide or the alumina raw material. If the composition of the binder is less than 1% by mass, the effect of adding the binder is not effective and the molded product cannot be maintained, which is not preferable. Further, if the amount of the binder exceeds 10% by mass, lamination occurs when the molded product is fired, and the product yield is extremely deteriorated. More preferably, it is in the range of 2-7% by mass.
本発明の耐火煉瓦の製造方法としては、配合された原料を一括あるいは分割して混練しする。混練に使用する混合機、混練機は一般に使用されている装置を用いることができる。また、混練後の原料は加圧成型されるが、このときに使用される加圧成型機も一般的に使用されている装置で足りる。成型時の成形圧力は通常0.2t/cm2-3.0t/cm2であり、締め回数は１回から数十回である。 As a method for producing refractory bricks of the present invention, the blended raw materials are kneaded in a batch or in a divided manner. As the mixer and the kneader used for kneading, generally used equipment can be used. Further, the raw material after kneading is pressure-molded, and the pressure-molding machine used at this time is also a generally used device. Molding pressure during molding is usually 0.2t / cm 2 -3.0t / cm 2 , tightening the number is several tens of times from one.
本発明品は成形後に熱処理することで施工に耐え得る強度を発揮できる。加熱に必要な炉は温度が十分に調整可能で均質加熱できる加熱炉であればどのような形式のものでも使用できる。 The product of the present invention can exhibit strength that can withstand construction by heat-treating after molding. The furnace required for heating can be of any type as long as the temperature can be sufficiently adjusted and homogeneous heating can be performed.
本発明の焼成マグネシア−クロム質煉瓦は、前記したクロミアの分解温度である1220℃以下の温度、あるいは1220℃以上であっても比較的短い時間曝される部位に適応される。本発明が適応される部位として、例えば亜鉛、銅、アルミニウム精錬に使用する炉や容器、転炉の出鋼口スリーブが挙げられる。 The calcined magnesia-chromic brick of the present invention is applied to a portion exposed to a temperature of 1220 ° C. or lower, which is the decomposition temperature of chromia described above, or 1220 ° C. or higher for a relatively short time. Examples of sites to which the present invention is applied include furnaces and containers used for refining zinc, copper and aluminum, and steel outlet sleeves for converters.
上記転炉の出鋼口スリーブ煉瓦に適用することで、以下の実施例で示すように従来にない耐用性を得ることが可能となる。出鋼口スリーブには一体方式と分割方式とがあるが、そのいずれであっても適用することができる。 By applying it to the steel outlet sleeve brick of the converter, it is possible to obtain unprecedented durability as shown in the following examples. There are two types of steel outlet sleeves, an integrated type and a split type, and either of them can be applied.
＜実施例および比較例＞
＜実施例１＞
以下の表1に記載する配合割合にて、本発明品の焼成マグネシア−クロム質煉瓦を作成した。また、表2に記載する割合にて、比較品の煉瓦を作成した。
<Examples and Comparative Examples>
<Example 1>
The calcined magnesia-chromic bricks of the present invention were prepared at the blending ratios shown in Table 1 below. In addition, comparative bricks were prepared at the ratios shown in Table 2.
耐スポーリング性については溶銑浸漬スポーリング試験で評価した。試料サイズは40×40×230mmとし、残留揮発分による爆裂防止のために事前に還元雰囲気下において1000℃で3時間熱処理した。試験は1700℃に昇温した溶銑に1分間浸漬後、15秒水冷した。評価方法には超音波非破壊試験器（UST）を用いた。試験前後での超音波の伝搬時間の変化率を測定した。変化率は0以上から70未満は◎、70以上から90未満を○、90以上から100未満を△、水冷後にれんがが折損し、USTによる評価が出来なかったものは×と評価した。 The spalling resistance was evaluated by a hot metal immersion spalling test. The sample size was 40 × 40 × 230 mm, and heat treatment was performed in advance at 1000 ° C. for 3 hours in a reducing atmosphere to prevent explosion due to residual volatile matter. The test was carried out by immersing in hot metal heated to 1700 ° C. for 1 minute and then cooling with water for 15 seconds. An ultrasonic non-destructive tester (UST) was used as the evaluation method. The rate of change in ultrasonic wave propagation time before and after the test was measured. The rate of change was evaluated as ◎ for 0 or more and less than 70, ○ for 70 or more and less than 90, Δ for 90 or more and less than 100, and × for those whose bricks were broken after water cooling and could not be evaluated by UST.
耐食性は、酸素-プロパン加熱による回転ドラム侵食試験を実施した。侵食剤としてSiO2=58質量%、Fe2O3=20質量%、CaO=20質量%、MgO=2質量%を用いて、1650℃、5時間の条件で実施した。侵食剤は1時間毎に取り換え、試験後の試料を長手方向に中央で切断し、侵食量を測定した。侵食量は、比較例１のマグネシア−カーボン質煉瓦を100とした溶損指数化した。値が小さいほど耐食性が高いことを示している。溶損指数が50から70未満は◎、70から90未満を○、90から100未満は△と評価した。 For corrosion resistance, a rotary drum erosion test was performed by heating with oxygen-propane. Using SiO 2 = 58% by mass, Fe 2 O 3 = 20% by mass, CaO = 20% by mass, and MgO = 2% by mass as the erosion agent, the test was carried out at 1650 ° C. for 5 hours. The erosion agent was changed every hour, and the sample after the test was cut in the center in the longitudinal direction, and the amount of erosion was measured. The amount of erosion was indexed with the magnesia-carbon brick of Comparative Example 1 as 100. The smaller the value, the higher the corrosion resistance. A erosion index of 50 to less than 70 was evaluated as ⊚, 70 to less than 90 was evaluated as ○, and 90 to less than 100 was evaluated as △.
耐摩耗性についてはJIS R 2252-1に準じて評価を行った。試料の摩耗体積は、比較例１のマグネシア−カーボン質煉瓦を100として指数化した。値が小さいほど摩耗量が小さいことを示している。摩耗指数が50から70未満は◎、70から90未満を○、90から100未満を△、100は×と評価した。 The wear resistance was evaluated according to JIS R 2252-1. The wear volume of the sample was indexed with the magnesia-carbon brick of Comparative Example 1 as 100. The smaller the value, the smaller the amount of wear. A wear index of 50 to less than 70 was evaluated as ⊚, 70 to less than 90 was evaluated as ○, 90 to less than 100 was evaluated as △, and 100 was evaluated as ×.
最終的な煉瓦の評価としては、いずれの評価項目も△は許容範囲のとし、×が1つでもついていたものは不適とした。各評価の結果、本発明品はいずれも耐スポーリング性、耐食性、耐摩耗性に優れているものであることが分かる。 As for the final evaluation of bricks, △ was considered to be within the permissible range for all evaluation items, and those with even one × were considered unsuitable. As a result of each evaluation, it can be seen that all of the products of the present invention are excellent in spalling resistance, corrosion resistance and wear resistance.
一方、比較例1は出鋼口スリーブで従来の工程で使用されてきたマグネシア−カーボン質煉瓦であり、耐スポーリング性、耐食性には優れるものの、耐摩耗性に劣り、好ましくない。 On the other hand, Comparative Example 1 is a magnesia-carbon brick that has been used in a conventional process for a steel outlet sleeve, and although it is excellent in spalling resistance and corrosion resistance, it is inferior in abrasion resistance and is not preferable.
比較例２は焼成マグネシア−クロム質煉瓦にピッチを含浸していない場合であり、耐食性、耐摩耗性には優れるものの、耐スポーリング性に劣り、好ましくない。 Comparative Example 2 is a case where the calcined magnesia-chromium brick is not impregnated with pitch, and although it is excellent in corrosion resistance and wear resistance, it is inferior in spalling resistance and is not preferable.
比較例３はマグネシア−クロム質煉瓦を焼成しておらず、ピッチも含浸していない場合であり、耐スポーリング性、耐食性には優れるものの、耐摩耗性には劣り、好ましくない。 Comparative Example 3 is a case where the magnesia-chromium brick is not fired and the pitch is not impregnated. Although it is excellent in spalling resistance and corrosion resistance, it is inferior in abrasion resistance and is not preferable.
本発明品を出鋼口スリーブに使用した。本発明品のうち、本発明品4,8,16を実機にてテストを行った。当該出鋼口スリーブで従来の工程で使用されていた比較例1のマグネシア−カーボン質煉瓦であり、平均161chで交換に到っていた。一方、本発明品の焼成マグネシア−クロム質煉瓦は本発明品4,8,16のそれぞれで216ch,197ch,201chで交換に到り、本発明品は何れも比較例１のマグネシア−カーボン質煉瓦に比べ損傷が小さく優れた結果であり、本発明の優位性は明らかである。
The product of the present invention was used for the steel outlet sleeve. Of the products of the present invention, products 4, 8 and 16 of the present invention were tested on an actual machine. It was a magnesia-carbon brick of Comparative Example 1 used in the conventional process for the steel outlet sleeve, and was replaced with an average of 161 channels. On the other hand, the fired magnesia-chromic bricks of the present invention were replaced at 216ch, 197ch, and 201ch in each of the products 4, 8 and 16, respectively, and all of the products of the present invention were magnesia-carbon bricks of Comparative Example 1. This is an excellent result with less damage than the above, and the superiority of the present invention is clear.
以上説明したように、本発明は、ピッチを含浸することによって、耐スポーリングを高めるとともに、マグネシア−クロム質煉瓦の本来の特性である、耐食性、耐酸化性、耐磨耗性を備えたマグネシア−クロム質煉瓦を得ることができるので、亜鉛、銅、アルミニウム精錬に使用する炉や容器、転炉の出鋼口スリーブに適用することができる。 As described above, the present invention enhances spalling resistance by impregnating pitch, and magnesia having corrosion resistance, oxidation resistance, and abrasion resistance, which are the original characteristics of magnesia-chromium bricks. -Since chrome bricks can be obtained, it can be applied to furnaces and containers used for refining zinc, copper and aluminum, and steel outlet sleeves for converters.
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