JP6344621B2 - Magnesia spinel fired brick manufacturing method - Google Patents
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- JP6344621B2 JP6344621B2 JP2016058481A JP2016058481A JP6344621B2 JP 6344621 B2 JP6344621 B2 JP 6344621B2 JP 2016058481 A JP2016058481 A JP 2016058481A JP 2016058481 A JP2016058481 A JP 2016058481A JP 6344621 B2 JP6344621 B2 JP 6344621B2
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- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 title claims description 87
- 239000011029 spinel Substances 0.000 title claims description 53
- 229910052596 spinel Inorganic materials 0.000 title claims description 53
- 239000000395 magnesium oxide Substances 0.000 title claims description 45
- 239000011451 fired brick Substances 0.000 title claims description 20
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 239000002994 raw material Substances 0.000 claims description 75
- 238000005245 sintering Methods 0.000 claims description 41
- 239000011449 brick Substances 0.000 claims description 34
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 32
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 24
- 238000010304 firing Methods 0.000 claims description 20
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 3
- 239000004615 ingredient Substances 0.000 claims 1
- 235000012245 magnesium oxide Nutrition 0.000 description 35
- 230000007797 corrosion Effects 0.000 description 18
- 238000005260 corrosion Methods 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 12
- 238000004901 spalling Methods 0.000 description 12
- 239000011230 binding agent Substances 0.000 description 11
- 238000002156 mixing Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 8
- 238000000465 moulding Methods 0.000 description 8
- 238000001816 cooling Methods 0.000 description 5
- 238000005336 cracking Methods 0.000 description 5
- 239000004568 cement Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000003628 erosive effect Effects 0.000 description 4
- 238000004898 kneading Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000005755 formation reaction Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 238000005485 electric heating Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- 239000004375 Dextrin Substances 0.000 description 1
- 229920001353 Dextrin Polymers 0.000 description 1
- 229910020068 MgAl Inorganic materials 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- ATRMIFNAYHCLJR-UHFFFAOYSA-N [O].CCC Chemical compound [O].CCC ATRMIFNAYHCLJR-UHFFFAOYSA-N 0.000 description 1
- -1 blending amounts Substances 0.000 description 1
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical class [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 235000019425 dextrin Nutrition 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 235000012907 honey Nutrition 0.000 description 1
- 238000013003 hot bending Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 235000010981 methylcellulose Nutrition 0.000 description 1
- 235000013379 molasses Nutrition 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000011010 synthetic spinel Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Description
本発明は、マグネシア・スピネル焼成煉瓦、特に、セメントキルンに用いるマグネシア・スピネル焼成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 a magnesia-spinel fired brick, particularly a magnesia-spinel fired brick used for a cement kiln.
セメントロータリーキルンには、一般的に、マグネシア‐スピネル質煉瓦及び/又はマグネシア‐クロム質煉瓦が内張りされている。そして、特に、熱負荷が大きく使用条件の厳しい所謂“焼成帯”と称されるゾーンには、耐熱性、耐食性、及び、セメントコーティングの付着性（以下“コーティング付着性”と称する）に優れたマグネシア‐クロム質煉瓦（以下“マグクロ煉瓦”と称する）が一般的に使用されてきた。 Cement rotary kilns are typically lined with magnesia-spinel bricks and / or magnesia-chromic bricks. In particular, the so-called “firing zone” having a large heat load and severe use conditions is excellent in heat resistance, corrosion resistance, and cement coating adhesion (hereinafter referred to as “coating adhesion”). Magnesia-chromic brick (hereinafter referred to as “magcro brick”) has been commonly used.
ところで、マグクロ煉瓦は、使用中に６価のクロム化合物を生成する可能性があり、環境保全の観点から問題があるため、クロムフリー化の推進によりマグネシア・スピネル質耐火物が主流となっている。このマグネシア・スピネル煉瓦は、高純度マグネシアクリンカーと合成スピネルクリンカーとから成り、良好な耐熱衝撃抵抗性を有するという特徴がある。その反面、マグクロ煉瓦と比較してコーティング付着性に劣り、熱間強度が比較的低いため、キルンの回転運動に起因する機械的応力に対する抵抗性に乏しく、熱負荷の厳しい特に焼成帯などでは、耐用性に劣るという欠点がある。 By the way, magchrom bricks may generate hexavalent chromium compounds during use, and are problematic from the viewpoint of environmental protection. Therefore, magnesia and spinel refractories have become mainstream due to the promotion of chromium-free. . This magnesia spinel brick consists of a high-purity magnesia clinker and a synthetic spinel clinker, and is characterized by having good thermal shock resistance. On the other hand, the coating adhesion is inferior to that of magcro bricks and the hot strength is relatively low, so the resistance to mechanical stress caused by the rotational movement of the kiln is poor, especially in the firing zone where the heat load is severe, There is a drawback of poor durability.
コーティング付着性の改善については、例えば、特許文献１には骨材として５〜３０質量％のマグネシアアルミナクリンカーと１０〜５０質量％の電融マグネシアクリンカーを使用し、結合部に部分安定化されたZrO2を０．５〜１０質量％を含むマグネシア・スピネル煉瓦が紹介されている。ジルコニアを添加することで、半溶融セメントに対する濡れ性を向上させ、耐侵食性を向上せしめ、かつ、結合強度を向上させるとしている。しかし、強度の向上は認められるものの、十分とはいえなかった。 For improving coating adhesion, for example, Patent Document 1 uses 5 to 30% by mass of magnesia alumina clinker and 10 to 50% by mass of electrofused magnesia clinker as aggregates, and is partially stabilized at the joint. Magnesia spinel bricks containing 0.5-10% by weight of ZrO 2 are introduced. By adding zirconia, the wettability to semi-molten cement is improved, the erosion resistance is improved, and the bond strength is improved. However, although an improvement in strength was observed, it was not sufficient.
さらに熱間強度を上げるための対策として、例えば特許文献２には、マグネシア・スピネルれんが全体に含まれるAl2O3が５〜１３質量％とし、更に、アルミナを２〜４質量％と、ジルコニアを０．５〜４質量％を含有せしめて１４００〜１８００℃で焼成するマグネシア・スピネル煉瓦が開示されている。アルミナを添加することで、焼成過程で、アルミナ原料とマグネシアとを反応焼結させ、高い熱間特性と優れた耐食性を有するとしている。 As a measure to further increase the hot strength, for example, Patent Document 2 discloses that 5 to 13% by mass of Al 2 O 3 contained in the entire magnesia / spinel brick, 2 to 4% by mass of alumina, and zirconia. Magnesia-spinel bricks containing 0.5 to 4% by mass and fired at 1400 to 1800 ° C. are disclosed. By adding alumina, the alumina raw material and magnesia are reacted and sintered in the firing process, and it has high hot characteristics and excellent corrosion resistance.
しかしながら、特許文献２に開示されている組成では、製造条件によっては焼成中に煉瓦表面に亀裂が発生し、歩留りの低下が著しく大きかった。 However, in the composition disclosed in Patent Document 2, cracks occurred on the brick surface during firing depending on the production conditions, and the yield was significantly reduced.
すなわち、煉瓦の原料にMgOとAl2O3が含まれることで、焼成中にAl2O3‐MgO スピネル（MgAl2O4）が生成し、当該Al2O3‐MgOスピネル生成によって体積膨張が起こる。一方、Al2O3はマグネシア原料に不純物成分として含まれるCaO成分と反応して、低融点の液相を生成し、その液相の存在によって焼結を促進する。この焼結によって体積の収縮が起こるが、前記スピネルの生成による膨張とのバランスが崩れると亀裂が発生することになり、歩留まりが低下することになる。更に、焼成後の煉瓦に未反応のAl2O3が過剰に残留すると、使用中にスピネルを生成し膨張することになるので好ましくない。 In other words, the inclusion of MgO and Al 2 O 3 in the brick material produced Al 2 O 3 -MgO spinel (MgAl 2 O 4 ) during firing, and volume expansion due to the formation of the Al 2 O 3 -MgO spinel. Happens. On the other hand, Al 2 O 3 reacts with the CaO component contained as an impurity component in the magnesia raw material to generate a low melting point liquid phase, and the presence of the liquid phase promotes sintering. This sintering causes volume shrinkage, but if the balance with expansion due to the generation of the spinel is lost, cracks will occur and the yield will decrease. Furthermore, if unreacted Al 2 O 3 remains excessively in the fired brick, spinel is generated and expanded during use, which is not preferable.
本発明は、アルミナを添加したマグネシア・スピネル煉瓦の焼成中に発生する亀裂を抑制し、歩留りの低下を抑え、更に、使用中の亀裂の発生も抑えたマグネシア・スピネル煉瓦の製造方法を提供することを目的としたものである。 The present invention provides a method for producing a magnesia-spinel brick that suppresses cracks that occur during firing of magnesia-spinel bricks to which alumina is added, suppresses a decrease in yield, and further suppresses the occurrence of cracks during use. It is for the purpose.
本発明はマグネシア・スピネル焼成煉瓦の製造方法であって、骨材となるマグネシア原料、スピネル原料に加えて、アルミナ原料２〜８質量％と、Al2O3を含有量が３〜２５質量％であり気孔率が１０〜２０％のマグネシアとスピネルの焼結原料を２０〜６０質量％とを混合して焼成し、煉瓦全体のAl2O3含有量が３〜２５質量％とした。 The present invention is a method for producing a magnesia-spinel fired brick, and in addition to the magnesia raw material and spinel raw material to be aggregates, the alumina raw material is 2 to 8% by mass and the content of Al 2 O 3 is 3 to 25% by mass. The sintered material of magnesia and spinel having a porosity of 10 to 20% was mixed and fired with 20 to 60% by mass, so that the Al 2 O 3 content of the entire brick was 3 to 25% by mass.
本発明により、焼成時の膨張と収縮のバランスがとれ、焼成中の亀裂発生を抑制することができ、歩留りを向上させることができるとともに、使用中の亀裂の発生も抑えることができる。 According to the present invention, the expansion and contraction during firing can be balanced, crack generation during firing can be suppressed, yield can be improved, and crack generation during use can also be suppressed.
本発明は、マグネシア原料とスピネル原料とを主成分とするマグネシア・スピネル焼成煉瓦であって、前記マグネシア原料とスピネル原料に加えて、アルミナ原料と、マグネシアとスピネルの焼結原料を配合して焼成、煉瓦全体のAl2O3含有量が所定範囲の量になるようにしたものである。 The present invention is a magnesia-spinel fired brick mainly composed of a magnesia raw material and a spinel raw material. In addition to the magnesia raw material and the spinel raw material, an alumina raw material and a sintered raw material of magnesia and spinel are blended and fired. The Al 2 O 3 content of the entire brick is in a predetermined range.
＜配合割合の範囲等＞
前記マグネシア原料には、市販されている天然マグネシア、焼結マグネシア、電融マグネシア等のマグネシアを主体としたものでMgO含有量が９０質量％以上であればいずれを使用してもかまわないし、混合して使用してもかまわない。純度が９０質量％未満では、不純物により各成分の機能が損なわれると共に、マグネシアクリンカーそのものの耐食性が低下するため好ましくない。より好ましくはMgO含有量が９７質量％以上である。
<Range of blending ratio, etc.>
As the magnesia raw material, commercially available natural magnesia, sintered magnesia, electrofused magnesia and other magnesia are mainly used, and any MgO content may be used as long as it is 90% by mass or more. Can be used. If the purity is less than 90% by mass, the function of each component is impaired by impurities, and the corrosion resistance of the magnesia clinker itself is lowered, which is not preferable. More preferably, the MgO content is 97% by mass or more.
当該マグネシア原料は３０〜８０質量％配合される。３０質量％未満では耐食性が低下し、８０質量％を超えると耐スポーリング性が低下するため好ましくない。 The said magnesia raw material is mix | blended 30-80 mass%. If it is less than 30% by mass, the corrosion resistance is lowered, and if it exceeds 80% by mass, the spalling resistance is lowered.
スピネル原料は、MgOとAl2O3の合量が９０質量％以上、かつAl2O3を４０〜７５質量％含んでいれば焼結品、電融品のいずれでも使用可能であり、両者を混ぜて使用してもかまわない。Al2O3含有量が４０質量％未満、７５質量％を超える場合は、Al2O3-MgOスピネルの結晶量が不充分となり、低熱膨張性が得られ難いため、好ましくない。より好ましくはMgOとAl2O3の合量が９８質量％以上である。 The spinel raw material can be used for both sintered and electrofused products if the total amount of MgO and Al 2 O 3 is 90 mass% or more and contains 40 to 75 mass% of Al 2 O 3. You can mix and use. When the Al 2 O 3 content is less than 40% by mass or more than 75% by mass, the amount of Al 2 O 3 —MgO spinel crystals becomes insufficient, and low thermal expansion is difficult to obtain, which is not preferable. More preferably, the total amount of MgO and Al 2 O 3 is 98% by mass or more.
当該スピネル原料は２〜４０質量％配合される。２質量％未満では耐スポーリング性が低下し、４０質量％を超えると耐食性が低下するため好ましくない。 The spinel raw material is blended in an amount of 2 to 40% by mass. If it is less than 2% by mass, the spalling resistance is lowered, and if it exceeds 40% by mass, the corrosion resistance is lowered.
本発明のマグネシア・スピネル焼成煉瓦には後述するように３〜２５質量％のAl2O3が含有される。当該Al2O3の量を確保する必要上、アルミナ原料が更に添加される。当該添加されるアルミナ原料は、純度９８％以上の焼結品、電融品、仮焼品、あるいはそれらの混合品を使用することができる。 The magnesia-spinel fired brick of the present invention contains 3 to 25% by mass of Al 2 O 3 as described later. In order to secure the amount of Al 2 O 3 , an alumina raw material is further added. As the alumina raw material to be added, a sintered product having a purity of 98% or more, an electromelted product, a calcined product, or a mixture thereof can be used.
当該アルミナ原料の添加量は外掛け２〜８質量％である。２質量％以下では、熱間強度の向上が不充分となり、８質量％超では、亀裂が発生するため、好ましくない。より好ましくは、外掛け３〜５質量％である。 The amount of the alumina raw material added is 2-8% by mass. If it is 2% by mass or less, the improvement in hot strength is insufficient, and if it exceeds 8% by mass, cracks are generated. More preferably, the outer covering is 3 to 5% by mass.
粒度は、１００メッシュ（０．１５mm）以下のアルミナを使用することができ、好ましくは３２５メッシュ（０．０４５mm）以下である。１００メッシュ（０．１５mm）を超える場合、マトリックス中のアルミナの分布が不足するため、焼成中のスピネル結合の形成が不充分となり、充分な熱間強度が得られ難いので好ましくない。 Alumina having a particle size of 100 mesh (0.15 mm) or less can be used, and preferably 325 mesh (0.045 mm) or less. When it exceeds 100 mesh (0.15 mm), the distribution of alumina in the matrix is insufficient, so that spinel bonds are not sufficiently formed during firing, and it is difficult to obtain sufficient hot strength, which is not preferable.
本発明では、前記マグネシア原料、スピネル原料、アルミナ原料に加えてマグネシアとスピネルの焼結原料が配合される。当該焼結原料は、ペリクレースとスピネルからなり、Al2O3を３〜２５質量％含有し、気孔率が１０〜２０％のものであれば使用可能である。 In the present invention, in addition to the magnesia raw material, spinel raw material, and alumina raw material, a sintering raw material of magnesia and spinel is blended. The sintering raw material is composed of periclase and spinel, can contain 3 to 25% by mass of Al 2 O 3 and has a porosity of 10 to 20%.
Al2O3の含有量が３質量％未満では、耐スポーリング性が低下するため好ましくない、２５質量％を超えると、耐食性が低下するため好ましくない。より好ましくは５〜２０質量％である。また、気孔率が１０％未満では、焼成亀裂の発生が抑えられない、２０％を超えると耐食性が低下するため好ましくない。より好ましくは１３〜１８％である。 When the content of Al 2 O 3 is less than 3% by mass, the spalling resistance is lowered, which is not preferable. When it exceeds 25% by mass, the corrosion resistance is decreased, which is not preferable. More preferably, it is 5-20 mass%. Moreover, if the porosity is less than 10%, the occurrence of firing cracks cannot be suppressed, and if it exceeds 20%, the corrosion resistance decreases, which is not preferable. More preferably, it is 13 to 18%.
前記気孔率が２０％より高い場合は当該焼結原料は焼結不足であり、煉瓦焼成時に再焼結が進行し亀裂の発生が抑制できないのに加えて、耐食性に劣ることになる。また、気孔率が１０％より低い場合は、当該焼結原料が緻密になっていることを意味し、耐スポーリング性が低下する。 When the porosity is higher than 20%, the sintering raw material is insufficiently sintered, and re-sintering proceeds at the time of baking the brick, so that the generation of cracks cannot be suppressed, and the corrosion resistance is inferior. Moreover, when the porosity is lower than 10%, it means that the sintering raw material is dense, and the spalling resistance is lowered.
焼結原料の製造方法については、原料配合物を一括あるいは分割して、更に、必要に応じて水を添加して混合機又は混練機により混合及び混練し、成形、焼成する。焼結温度は１４００℃以上とすることがより好ましい。焼結原料の焼結温度が１４００℃未満の場合、これを配合したマグネシア・スピネル質耐火煉瓦の収縮が大きくなり亀裂が発生しやすくなる。より好ましくは，１４５０℃以上である。焼結温度の上限は特には規定しないが、経済的観点から２０００℃以下とすることが望ましい。このようにして製造した焼結体を粉砕し、所定の粒度に調整して焼結原料として利用する。 About the manufacturing method of a sintering raw material, a raw material compound is batched or divided | segmented, Furthermore, water is added as needed, and it mixes and kneads with a mixer or a kneader, and shape | molds and bakes. The sintering temperature is more preferably 1400 ° C. or higher. When the sintering temperature of the sintering raw material is less than 1400 ° C., the shrinkage of the magnesia-spinel refractory brick containing this increases, and cracks are likely to occur. More preferably, it is 1450 degreeC or more. The upper limit of the sintering temperature is not particularly specified, but is preferably 2000 ° C. or less from an economic viewpoint. The sintered body thus manufactured is pulverized, adjusted to a predetermined particle size, and used as a sintering raw material.
この焼結原料としては、前記製造方法の他、１４００℃以上で焼成した焼成煉瓦を製造し粉砕したものでも、１４００℃以上で焼成した焼成煉瓦の使用後を回収し粉砕したものでも、Al2O3含有量と気孔率が規定範囲であれば使用しても差し支えない。 As this sintering raw material, in addition to the production method described above, a fired brick baked at 1400 ° C. or higher and pulverized, or a fired brick baked at 1400 ° C. or higher recovered and pulverized, Al 2 If the O 3 content and porosity are within the specified ranges, they can be used.
焼結原料の使用量は、２０〜６０質量％で好ましくは３０〜５０質量％の範囲内である。２０質量％未満では、亀裂の発生が抑えられず、６０質量％超では耐食性、成形性、強度が低下するため好ましくない。粒度は、JIS規格Z8801-1の試験用ふるい‐第1部：金属製網ふるいを使用し、３．３５mmの篩下であれば使用可能であり、３．３５mm以上が１０質量％以下、７５μm以下が２０質量％以下が好ましい。３．３５mm以上が１０質量％以上の場合、強度が低下し、７５μm以下が２０質量％以上の場合、亀裂の発生が抑えられない。 The usage-amount of a sintering raw material is 20-60 mass%, Preferably it exists in the range of 30-50 mass%. If it is less than 20% by mass, the occurrence of cracks cannot be suppressed, and if it exceeds 60% by mass, the corrosion resistance, moldability and strength are lowered, which is not preferable. Grain size is JIS standard Z8801-1 test sieve-Part 1: Metal mesh sieve can be used if it is 3.35mm under sieve, 3.35mm or more is 10% by mass or less, 75μm The following is preferably 20% by mass or less. When the thickness of 3.35 mm or more is 10% by mass or more, the strength decreases, and when 75 μm or less is 20% by mass or more, the occurrence of cracks cannot be suppressed.
また、本発明のマグネシア・スピネル焼成煉瓦には、ジルコニアを４質量％以下（ゼロを含む）配合させても良い。マグネシア・スピネル煉瓦中のZrO2起源にも特に制限は設けないが、焼成中にCaOと粒子間結合を形成しやすくするため、未安定化ZrO2を含む原料が望ましい。 Moreover, you may mix | blend 4 mass% or less (including zero) zirconia with the magnesia spinel baking brick of this invention. Although there is no particular restriction on the origin of ZrO 2 in magnesia spinel brick, a raw material containing unstabilized ZrO 2 is desirable to facilitate the formation of interparticle bonds with CaO during firing.
本発明のマグネシア・スピネル焼成煉瓦中のAl2O3含有量は３〜２５質量％で、より好ましくは１０〜１７質量％である。Al2O3の含有量が３質量％未満では耐スポーリング性が低下するため好ましくない。Al2O3含有量が２５質量％を超える場合は、耐食性が低下するため好ましくない。 The Al 2 O 3 content in the magnesia-spinel fired brick of the present invention is 3 to 25% by mass, more preferably 10 to 17% by mass. If the content of Al 2 O 3 is less than 3% by mass, the spalling resistance is lowered, which is not preferable. When the Al 2 O 3 content exceeds 25% by mass, the corrosion resistance is lowered, which is not preferable.
本発明のマグネシア・スピネル焼成煉瓦は、前記したようにマグネシア原料、スピネル原料、アルミナ原料、焼結原料が粉砕・混練（混合）されバインダーを混入して成型される。 As described above, the magnesia-spinel fired brick of the present invention is formed by pulverizing and kneading (mixing) a magnesia raw material, a spinel raw material, an alumina raw material, and a sintered raw material, and mixing a binder.
バインダーには有機バインダー又は無機バインダーを配合できる。有機バインダーとしては、ピッチやフェノール樹脂、トウミツ、パルプ廃液、デキストリン、メチルセルロース類、ポリビニルアルコール等種々のバインダーを使用できる。 An organic binder or an inorganic binder can be mix | blended with a binder. As the organic binder, various binders such as pitch, phenol resin, honey, pulp waste liquid, dextrin, methylcelluloses, polyvinyl alcohol and the like can be used.
混練（混合）には、容器固定型としてローラー式のSWPやシンプソンミキサー、ブレード式のハイスピードミキサー、加圧ハイスピードミキサー、ヘンシェルミキサー、加圧ニーダーと呼ばれる混練機が使用される。容器駆動型としては、ローラー式のMKPやウエットパン、コナーミキサー、ブレード式のアイリッヒミキサー、ボルテックスミキサー等の混練機が使用される。また、これらの混練機や混合機に加圧もしくは減圧、温度制御装置等（加温や冷却もしくは保温）を付ける場合もある。混合もしくは混練時間は原料の種類、配合量、バインダーの種類、温度（室温、原料やバインダー）、混合機もしくは混練機の種類や大きさによって異なるが、通常数分から数時間である。 For kneading (mixing), a roller-type SWP, a Simpson mixer, a blade-type high-speed mixer, a pressurized high-speed mixer, a Henschel mixer, or a pressure kneader is used as a container-fixing type. As the container drive type, a kneading machine such as a roller type MKP, a wet pan, a Conner mixer, a blade type Eirich mixer, a vortex mixer or the like is used. In some cases, these kneaders and mixers are subjected to pressurization or depressurization, a temperature control device or the like (heating, cooling or heat retention). The mixing or kneading time varies depending on the type of raw material, the blending amount, the type of binder, the temperature (room temperature, raw material and binder), the type and size of the mixer or kneader, but is usually from several minutes to several hours.
混練物は衝撃圧プレスであるフリクションプレス、スクリュープレスあるいはハイドロスクリュープレス等、静圧プレスである油圧プレスやトッグプレス等によって成形できる。その他にも、ランマープレスや振動プレス、CIPと呼ばれる成形機でも成形できる。これらの成形機には、真空脱気装置や温度制御装置（加温や冷却もしくは保温）等を付ける場合もある。プレス成形機による成形圧力や締め回数は成形される煉瓦の大きさ原料の種類、配合量、バインダーの種類、温度（室温、原料やバインダー）、成形機の種類や大きさによって異なる。 The kneaded material can be formed by a hydraulic press, a toggle press, or the like, such as a friction press, a screw press, or a hydro screw press, which is an impact pressure press. In addition, it can be molded by a molding machine called rammer press, vibration press or CIP. These molding machines may be provided with a vacuum deaeration device, a temperature control device (heating, cooling or heat retention) or the like. The molding pressure and the number of tightening by the press molding machine vary depending on the size of the brick to be molded, the type of raw material, the blending amount, the type of binder, the temperature (room temperature, raw material and binder), and the type and size of the molding machine.
前記成型後、成型物は焼成され、本発明のマグネシア・スピネル焼成煉瓦を得る。このときの加熱機としては電気加熱式、ガス加熱式、オイル加熱式などのバッチ式単独窯、例えばシャトルキルンやカーベルキルン等、連続式であればトンネル窯等が最適である。もちろん、温度が十分に調整可能で均質加熱ができる加熱炉であればどのような形式の物でも使用できる。 After the molding, the molded product is fired to obtain the magnesia-spinel fired brick of the present invention. As the heating machine at this time, a batch type kiln such as an electric heating type, a gas heating type, or an oil heating type, for example, a shuttle kiln, a carbell kiln or the like, a tunnel kiln or the like is optimal. Of course, any type of furnace can be used as long as the temperature is sufficiently adjustable and the furnace can perform homogeneous heating.
上記焼成時の焼成温度は１４００℃以上２０００℃以下が望ましい。１４００未満では、スピネル生成反応が充分でなく、２０００℃を超える場合は、焼成中に煉瓦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。好ましくは、１５００〜１８００℃である。 The firing temperature during the firing is preferably 1400 ° C. or more and 2000 ° C. or less. If it is less than 1400, spinel formation reaction is not sufficient, and if it exceeds 2000 ° C., problems such as deformation of bricks occur during firing, such being undesirable. Preferably, it is 1500-1800 degreeC.
＜実施例＞
実施例１
表１に使用したマグネシア原料，スピネル原料，アルミナ原料の化学組成を示す。
<Example>
Example 1
Table 1 shows the chemical composition of the magnesia, spinel and alumina materials used.
表２に焼結原料の化学組成と気孔率とを示す。焼結原料A〜Gは、Al2O3含有量を変化させたものであり、焼結後の気孔率が同じになるように、粒度配合、成型、焼結温度等の条件を変えた。焼結原料Ｄ１〜Ｄ６は焼結原料Ｄをベースに粒度配合、焼結温度等の条件を変えて気孔率を変化させてものである。 Table 2 shows the chemical composition and porosity of the sintering raw material. Sintering raw materials A to G were obtained by changing the content of Al 2 O 3 , and conditions such as particle size blending, molding, and sintering temperature were changed so that the porosity after sintering was the same. The sintering raw materials D1 to D6 are based on the sintering raw material D, and the porosity is changed by changing conditions such as particle size blending and sintering temperature.
表３と表４に、焼結原料の添加量を一定として焼結原料のAl2O3含有量と気孔率、焼結温度を変えた場合の検討結果を示し、表３が本発明品、表４が比較例を示す。 Tables 3 and 4 show the results of investigation when the amount of sintering raw material added is constant and the Al 2 O 3 content, porosity, and sintering temperature of the sintering raw material are changed. Table 3 shows the present invention product, Table 4 shows a comparative example.
表３、４に記載した各種原料を配合し、バインダーとして糖蜜を３質量％添加して混練し、油圧プレスを用いて１．２トン/cm2の成形圧力で２０回成形し１１５mm×６５mm×８０mmの試料を作成した。成形した試料はいずれも２００℃で２４時間乾燥後に電気加熱式の箱型電気炉を用いて所定の温度まで昇温５℃毎分で加熱し、所定の温度で１０時間保持後、５℃毎分で５００℃まで冷却した後に自然放冷した。 Various raw materials listed in Tables 3 and 4 were blended, 3% by mass of molasses was added as a binder, kneaded, and molded 20 times at a molding pressure of 1.2 ton / cm 2 using a hydraulic press, 115 mm x 65 mm x An 80 mm sample was prepared. Each of the molded samples was dried at 200 ° C. for 24 hours, then heated to a predetermined temperature using an electric heating box electric furnace at a temperature of 5 ° C. per minute, held at the predetermined temperature for 10 hours, and then every 5 ° C. After cooling to 500 ° C. in minutes, it was allowed to cool naturally.
亀裂は、焼成後の表面を確認し亀裂の発生状況を確認した。幅の広い亀裂の発生したものを×、ヘアクラックの発生があるものを○、亀裂なしを◎で評価した。 For cracks, the surface after firing was confirmed and the occurrence of cracks was confirmed. The case where a wide crack was generated was evaluated as x, the case where a hair crack was generated was evaluated as ○, and the case where there was no crack was evaluated as ◎.
スポーリング試験は、試料を５０mm角のサイコロ状に加工し、１２００℃１５min加熱→３min水冷→１２min空冷を1サイクルとして、割れるまで繰り返し、割れるまでの回数で評価した。回数が多いものほど耐スポーリング性に優れる。７回未満は×、８〜９回を△、１０〜１６回を○、１６回を超えるものを◎としている。 In the spalling test, a sample was processed into a 50 mm square dice, and 1200 ° C 15 min heating → 3 min water cooling → 12 min air cooling was repeated as one cycle until cracking, and the number of times until cracking was evaluated. The higher the number of times, the better the spalling resistance. Less than 7 times are marked as x, 8-9 times as Δ, 10-16 times as ◯, and more than 16 times as ◎.
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。侵食剤として市販のポルトランドセメントを用い、１７５０℃、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、侵食量を測定し実施例１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意味している。 For corrosion resistance, a rotating drum erosion test by oxygen-propane heating was performed. A commercially available Portland cement was used as the erodant, and the test was performed at 1750 ° C. for 5 hours. The erodant was replaced every hour, the sample after the test was cut in the center in the longitudinal direction, the amount of erosion was measured, and the erosion index was obtained with Example 1 as 100. The smaller the value, the higher the corrosion resistance.
熱間強度は、JISR2656の耐火れんが及び耐火断熱れんがの熱間曲げ強さ試験方法に準じ１２５０℃で測定した。５MPa未満を×、５〜７未満を△、７MPa〜１０未満を○、１０MPa以上を◎で評価した。 The hot strength was measured at 1250 ° C. according to the hot bending strength test method of JISR2656 refractory bricks and refractory thermal insulation bricks. Less than 5 MPa was evaluated as x, less than 5-7 was evaluated as Δ, less than 7 MPa was evaluated as ◯, and 10 MPa or more was evaluated as ◎.
本発明品１〜９は、焼結原料のAl2O3含有量を変化させた場合である。また、本発明品１０〜１４は、焼結温度を変えた場合であるが、焼結温度が変化しても気孔率の変化はほとんど無かった。本発明品は何れも焼成亀裂の発生はなく、熱間で高強度であり、耐スポーリング性もほぼ同等、耐食性もほぼ同等となっている。 Invention products 1 to 9 are cases in which the Al 2 O 3 content of the sintering raw material is changed. Moreover, although this invention products 10-14 are the cases where a sintering temperature is changed, there was almost no change of the porosity even if the sintering temperature changed. All the products of the present invention have no firing cracks, are hot and have high strength, have approximately the same spalling resistance and corrosion resistance.
それに対し、比較例１は焼結原料中のAl2O3含有量が２質量％と低い場合であるが、耐スポーリング性が低下した。比較例２は、焼結原料中のAl2O3含有量が３０質量％と過多の場合であるが、耐食性が低下し、熱間強度の向上もみられなかった。比較例３は、焼結原料の気孔率が８％と低すぎる場合であるが、耐スポーリング性が低下した。比較例４は、焼結原料の気孔率が２２％と高すぎる場合であるが、耐食性、熱間強度が低下した。 On the other hand, Comparative Example 1 is a case where the content of Al 2 O 3 in the sintered raw material is as low as 2% by mass, but the spalling resistance was lowered. Comparative Example 2 is a case where the content of Al 2 O 3 in the sintered raw material is excessive, as 30% by mass, but the corrosion resistance was lowered and the hot strength was not improved. Although the comparative example 3 is a case where the porosity of a sintering raw material is too low as 8%, spalling resistance fell. Although the comparative example 4 is a case where the porosity of a sintering raw material is too high as 22%, corrosion resistance and hot strength fell.
＜実施例２＞
表５と表６に、焼結原料の種類、配合量、マグネシア原料、スピネル原料、アルミナ原料を様々変化させて検討した場合の検討結果を示し、表５が本発明品、表６が比較例である。焼結原料の焼結温度は、いずれも１５００℃とした。評価方法は実施例１と同一である。
<Example 2>
Tables 5 and 6 show the results of investigations when various types of sintering raw materials, blending amounts, magnesia raw materials, spinel raw materials, and alumina raw materials were examined. Table 5 shows the product of the present invention, and Table 6 shows a comparative example. It is. The sintering temperature of the sintering raw material was 1500 ° C. for all. The evaluation method is the same as in Example 1.
本発明品３、１５〜１８は焼結原料の添加量を変化させたもの、本発明品１９〜２２は焼結原料中のAl2O3含有量を変化させたもの、本発明品２３〜２６は煉瓦中のAl2O3量を変化させたもの、本発明品２７〜３１は煉瓦へのアルミナ添加量を変化させたもの、３２〜３７は煉瓦の焼成温度を変化させたもの、本発明品３８〜４７は、焼結原料の粒度配合、マグネシア原料、スピネル原料、アルミナ原料を変えたものである。 Invention products 3, 15 to 18 are obtained by changing the addition amount of the sintering raw material, Invention products 19 to 22 are those obtained by changing the content of Al2O3 in the sintering raw material, and Invention products 23 to 26 are bricks. What changed the amount of Al2O3 in the present invention, 27 to 31 of the present invention was changed the amount of alumina added to the brick, 32 to 37 was changed the firing temperature of the brick, 38 to 47 of the present invention In this method, the grain size of the sintered raw material, the magnesia raw material, the spinel raw material, and the alumina raw material are changed.
本発明品は何れも焼成亀裂の発生はなく、熱間で高強度であり、耐スポーリング性もほぼ同等、耐食性もほぼ同等となっている。 All the products of the present invention have no firing cracks, are hot and have high strength, have approximately the same spalling resistance and corrosion resistance.
それに対し、比較例５は、焼結原料の添加量が１０質量％と少ない場合であるが、煉瓦の焼成亀裂が抑えられない。比較例６は、焼結原料の添加量が７０質量％と多すぎる場合であるが、耐食性と熱間強度に劣った。比較例７は、煉瓦中のAl2O3含有量が２．２９質量％と少なすぎる場合であるが、耐スポーリング性に劣り、熱間強度の向上も見られなかった。比較例８は、煉瓦中のAl2O3含有量が２７．１質量％と多すぎる場合であるが、耐食性に劣り、また、煉瓦に亀裂発生が発生した。比較例９は、アルミナ原料を添加しない場合であるが、熱間強度に劣った。比較例１０は、アルミナ原料の添加量が９質量％と多すぎる場合であるが、煉瓦に亀裂発生が発生した。 On the other hand, Comparative Example 5 is a case where the addition amount of the sintering raw material is as small as 10% by mass, but the fired cracks of the brick cannot be suppressed. Although the comparative example 6 is a case where the addition amount of a sintering raw material is too much as 70 mass%, it was inferior to corrosion resistance and hot strength. Comparative Example 7 is a case Al 2 O 3 content in the brick is too small and 2.29 wt%, inferior to the spalling resistance, improved hot strength was not observed. Comparative Example 8 is a case where the Al 2 O 3 content in the brick is too large at 27.1% by mass, but the corrosion resistance is inferior, and cracking occurred in the brick. In Comparative Example 9, the alumina raw material was not added, but the hot strength was inferior. In Comparative Example 10, although the amount of the alumina raw material added was too large, 9% by mass, cracks occurred in the brick.
以上のように、本発明の優位性は明らかである。 As described above, the superiority of the present invention is clear.
本発明により、高い熱間強度を有するマグネシア・スピネル焼成煉瓦において、焼成時の亀裂発生を抑制でき、歩留りを向上させることができるとともに、使用中の亀裂の発生も抑えることができる。 According to the present invention, in a magnesia-spinel fired brick having a high hot strength, cracking during firing can be suppressed, yield can be improved, and cracking during use can also be suppressed.
Claims (8)
アルミナ原料２〜８質量％と、Al2O3含有量が３〜２５質量％であり気孔率が１０〜２０％のマグネシアとスピネルの焼結原料を２０〜６０質量％と、残部のマグネシア原料とスピネル原料とを配合して焼成し、
焼成後の全体のAl2O3含有量が３〜２５質量％であることを特徴とするマグネシア・スピネル焼成煉瓦の製造方法。 In the manufacturing method of magnesia spinel fired brick,
20 to 60% by mass of magnesia and spinel sintering raw material having an alumina raw material of 2 to 8% by mass, Al 2 O 3 content of 3 to 25% by mass and porosity of 10 to 20%, and the remaining magnesia raw material And spinel ingredients and baked,
A method for producing a magnesia-spinel fired brick, wherein the total Al 2 O 3 content after firing is 3 to 25% by mass.
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