JP3723093B2 - Manufacturing method of high corrosion resistance refractory material - Google Patents
Manufacturing method of high corrosion resistance refractory material Download PDFInfo
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- JP3723093B2 JP3723093B2 JP2001122093A JP2001122093A JP3723093B2 JP 3723093 B2 JP3723093 B2 JP 3723093B2 JP 2001122093 A JP2001122093 A JP 2001122093A JP 2001122093 A JP2001122093 A JP 2001122093A JP 3723093 B2 JP3723093 B2 JP 3723093B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、ごみ焼却灰溶融炉、原子炉廃棄物溶融炉等の溶融スラグによる腐食が著しい耐火物に好適な高耐食性耐火物材の製造方法に関する。
【０００２】
【従来の技術】
耐火物の耐食性は、数ｍｍ程度の粗大な粒子を結合しているバインダーと称される１ｍｍ以下の粒子からなる部分の耐食性に大きく依存している。従来の例えば、Ｃｒ2Ｏ3−ＭｇＯ系耐火物では、このバインダー部分にＣｒ2Ｏ3とＭｇＯの混合物若しくはこれらが一部固溶した形の粒子が用いられていた。
このバインダー部分の耐食性は、Ｃｒ2Ｏ3とＭｇＯの固溶体量に依存し、高い耐食性のためにはＭｇＯが分子レベルで単独で存在しないバインダーとする必要がある。また、ＭｇＯ粒界が溶融スラグにより選択的に腐食を受けるため粒界結合を強固にし、腐食を受け難くする必要がある。
従来の方法では、Ｃｒ2Ｏ3粉末およびＭｇＯ粉末を混合し、焼成をおこなっていた。この方法では、Ｃｒ2Ｏ3とＭｇＯの固溶が十分に進まず、また粒界が溶融スラグに侵食されやすく、バインダーの耐食性が十分に向上しない問題があった。
【０００３】
【発明が解決しようとする課題】
本発明は、上記事情に対してなされたものであり、素材として均質であり、ごみ焼却灰溶融炉、原子炉廃棄物溶融炉等の溶融スラグによる腐食が著しい耐火物に好適な耐火物用バインダー材等の高耐食性耐火物材の製造方法を提供することを目的とする。
【０００４】
【課題を解決するための手段】
本発明者らは、上記事情のもとに、バインダー材としてＣｒ2Ｏ3とＭｇＯを混合して用いたバインダー材を製造する場合に、これらの素材の固溶促進のため助剤としてＹ2Ｏ3を用いることについて鋭意検討した。このＹ2Ｏ3は粒界エネルギーを下げることにより焼結に寄与するとともに粒界部分の選択的な腐食を抑制することに想到した。
【０００５】
すなわち、本発明に係る高耐食性耐火物材の製造方法は、上記目的を達成するために、Ｃｒ2Ｏ3粉末１００重量部に、ＭｇＯ粉末を２５重量部以上１５０重量部以下添加し、０．５重量部以上２重量部以下のＹ2Ｏ3粉末を添加したものを真空雰囲気中で１４００℃を越え１７００℃未満の温度で焼結することにより作製した焼結体を粉砕することより成ることを特徴とする。
【０００６】
本発明に係る高耐食性耐火物材は、Ｙ2Ｏ3粉末を0.5重量部以上１重量部以下添加したものを焼結、粉砕して製造することがさらに好適である。また、上記真空雰囲気は、１０-20〜１０-5ａｔｍの真空雰囲気が好適である。さらに、焼結温度は、１５００℃を越え１７００℃未満の温度がより好適である。
本発明の適用される高耐食性耐火物材としては、耐火物用バインダー材の他、骨材そのものを挙げることができる。
【０００７】
【発明の実施の形態】
本発明では、Ｃｒ2Ｏ3粉末１００重量部に、 ＭｇＯ粉末を２５重量部以上１５０重量部以下添加し、０．５重量部以上２重量部以下、好適には、０．５重量部以上１重量部以下のＹ2Ｏ3粉末を添加したものを調製する。
Ｃｒ2Ｏ3粉末としては、平均粒径０．１μｍ〜３μｍのものが好適である。粒径が０．１μｍであると粉末に著しい凝集が生じ、又粒径が３μｍ以上であると焼結性が低下するために緻密化しないからである。ＭｇＯ粉末としては、平均粒径０．１μｍ〜３μｍのものが好適である。
粒径が０．１μｍであると粉末に著しい凝集が生じ、又粒径が３μｍ以上であると焼結性が低下するために緻密化しないからである。また、Ｙ2Ｏ3粉末としては、平均粒径０．１μｍ〜３μｍのものが好適である。
粒径がこの範囲外であると均質に分散することが困難となるからである。
【０００８】
上記調製したものを例えばブタノール等のアルコール類、アセトン、キシレン、トルエンのような有機溶媒中で十分均質に混合する。
得られた混合物を乾燥し、例えば、圧力１００ｋｇｆ／ｃｍ2の一軸成形、圧力１０００ｋｇｆ／ｃｍ2の冷間静水圧成形を行って成形体を得る。
【０００９】
そして、上記成形体を焼結する。焼結雰囲気については、一般にセラミックスは大気圧での焼結が普通であるが、本発明を実施するには真空雰囲気にする必要がある。
この理由は、大気圧ではＣｒ2Ｏ3の酸化が進みＣｒＯ3となって焼結体内部で揮発及び他粒子との凝縮が行なわれるため、小さい粒子が粗大化し、焼結体の密度が低下するからである。すなわち、本発明では真空雰囲気、特に１０-5ａｔｍ以下とすることにより、Ｃｒイオンの酸化を防止して焼結体の密度を高く維持する。なお、真空度が著しく高くなって、特に１０-20ａｔｍ未満になるとＣｒイオンが還元されて金属クロムとなるおそれがあるため、真空度は１０-20〜１０-5ａｔｍが望ましい。なお、この真空度は、酸素分圧で表現している。
【００１０】
本発明では、Ｃｒ2Ｏ3とＭｇＯの合計に対して０．５重量部以上２重量部以下、好適には、０．５重量部以上１重量部以下のＹ2Ｏ3粉末を助剤として添加している。この助剤は、Ｃｒ2Ｏ3とＭｇＯの固溶を促進することにより、これらの均一な混合を助け、粒界エネルギーを下げて焼結に寄与するとともに、粒界部分の選択的な腐食を抑制する。添加量が、０．５重量部未満であると 粒界エネルギーを十分に低下させる事が困難となるためであり、２重量部を越えるとＹ２０３の選択腐食が生じて耐食性が損なわれるためである。
【００１１】
焼結温度は、原子の拡散速度を高めて焼結を容易にするためには、１４００℃以上とすべきであるが、１７００℃を超えた高温とすると逆に焼結密度が低下する傾向にあるので、１４００℃を越え、１７００℃未満が望ましい。なお、さらに好適には、１５００℃を越え１７００℃未満の温度である。
【００１２】
本発明に係る高耐食性耐火物材は、焼結体を破砕することによって得られる。破砕方法は、ジョークラッシャー、インパクトクラッシャーおよびボールミルによって粒径が１０００μｍ以下となるまで破砕するのが好適である。
【００１３】
【実施例】
実施例１
本発明に係る高耐食性耐火物材としてバインダー材を調製した。また、従来法によるバインダー材も調製した。
本発明に係るバインダー材では、Ｃｒ2Ｏ3粉末として平均粒径０．２μｍの粉末を用い、ＭｇＯ粉末として０．３μｍの粉末を用いた。Ｙ2Ｏ3粉末として平均粒径０．３μｍの粉末を用いた。また、従来法によるバインダー材として平均粒径０．２μｍのＣｒ2Ｏ3粉末と平均粒径０．２５μｍのＭｇＯ粉末を用いて本発明との比較を行った。
【００１４】
Ｃｒ2Ｏ3粉末を１００重量部とし、これにＭｇＯ粉末を１００重量部となるよう秤量した粉末に、１重量部のＹ2Ｏ3粉末を添加し、有機溶媒中であるブチルアルコールで混合機を用いて１２０時間混合した。得られた混合物を８０℃の真空乾燥機を用いて乾燥した。
この混合粉末圧力１００ｋｇｆ／ｃｍ2の一軸成形を行った後、圧力１０００ｋｇｆ／ｃｍ2の冷間静水圧加圧成形を行い成形を得た。この成形体を酸素分圧が１０-8ａｔｍの雰囲気中１２００℃〜１７００℃で３時間焼結した。
【００１５】
従来法によるバインダー材については、Ｃｒ2Ｏ3粉末１００重量部に対してＭｇＯ粉末を１００重量部となるよう添加しブチルアルコール中混合機を用いて１２０時間混合した。混合後８０℃の真空乾燥機を用いて乾燥した後、上述と同一の方法で成形し、酸素分圧が１０-8ａｔｍの真空中で３時間焼結を行った。
【００１６】
本発明に係るバインダー材に用いられるＣｒ2Ｏ3−ＭｇＯ―Ｙ2Ｏ3および従来法で焼結したＣｒ2Ｏ3−ＭｇＯの焼結密度の焼結温度依存性を表１に示す、表１に示すように、本発明に係るバインダー材では、１４００℃の焼結温度で９５％以上の焼結密度が得られる。また、従来法によるバインダー材では１６００℃の焼結温度で９５％以上の焼結密度が得られる。この焼結密度の向上は、Ｃｒ2Ｏ3とＭｇＯの固溶化に先立って必ず認められるもので、焼結密度が９５％以上になることが、Ｃｒ2Ｏ3とＭｇＯの十分な固溶化に必要である。
【００１７】
【表１】
本発明に係るバインダー材を得るための、Ｙ2Ｏ3粉末を１．０重量部添加したＣｒ2Ｏ3−ＭｇＯ焼結体の、内掛けで４５重量部のＳｉＯ2、３２．５重量部のＣａＯ及び２２．５重量部のＡｌ2Ｏ3からなる溶融スラグ中の１６００℃Ｘ１時間における腐食減量を表２に示す。表１には、比較として従来法で作製したＣｒ2Ｏ3−ＭｇＯ焼結体の、同様の組成の溶融スラグ中の１６００℃Ｘ１時間における腐食減量も示している。
【００１９】
【表２】
従来法に係るバインダー材に用いられる焼結体では、腐食減量が５００μｍ程度となるのに対し、本発明に係るバインダー材に用いられる焼結体では、腐食減量は５０μｍ程度となり高い耐食性を示す。Ｃｒ2Ｏ3とＭｇＯの固溶が促進され、かつ、Ｙ2Ｏ3の焼結助剤成分のスラグに対する耐食性が高いために、バインダー材の耐食性が向上していることが了解される。
【００２１】
【発明の効果】
上記説明したところから明らかなように、本発明によれば、素材として均質であり、ごみ焼却灰溶融炉、原子炉廃棄物溶融炉等の溶融スラグによる腐食が著しい耐火物に好適な耐火物用バインダー材等の高耐食性耐火物材が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a highly corrosion-resistant refractory material suitable for a refractory that is significantly corroded by molten slag, such as a refuse incineration ash melting furnace and a nuclear reactor waste melting furnace.
[0002]
[Prior art]
The corrosion resistance of the refractory depends largely on the corrosion resistance of a portion made of particles of 1 mm or less called a binder that binds coarse particles of about several mm. In conventional Cr 2 O 3 —MgO refractories, for example, a mixture of Cr 2 O 3 and MgO in the binder portion or a particle in which these are partly dissolved has been used.
The corrosion resistance of the binder portion depends on the amount of solid solution of Cr 2 O 3 and MgO. For high corrosion resistance, it is necessary to use a binder in which MgO is not present alone at the molecular level. Further, since the MgO grain boundary is selectively corroded by the molten slag, it is necessary to strengthen the grain boundary bond and make it difficult to be corroded.
In the conventional method, Cr 2 O 3 powder and MgO powder are mixed and fired. In this method, there is a problem that the solid solution of Cr 2 O 3 and MgO does not advance sufficiently, the grain boundary is easily eroded by the molten slag, and the corrosion resistance of the binder is not sufficiently improved.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and is a refractory binder suitable for refractories that are homogeneous as raw materials and that are significantly corroded by molten slag, such as refuse incineration ash melting furnaces, nuclear reactor waste melting furnaces, etc. It aims at providing the manufacturing method of highly corrosion-resistant refractory materials, such as materials.
[0004]
[Means for Solving the Problems]
In the case of producing a binder material using a mixture of Cr 2 O 3 and MgO as a binder material under the above circumstances, the present inventors use Y 2 as an auxiliary agent for promoting solid solution of these materials. The diligent study was conducted on the use of O 3 . This Y 2 O 3 was conceived to contribute to sintering by lowering the grain boundary energy and to suppress selective corrosion of the grain boundary part.
[0005]
That is, in order to achieve the above object, the method for producing a highly corrosion-resistant refractory material according to the present invention adds MgO powder to 25 parts by weight or more and 150 parts by weight or less to 100 parts by weight of Cr 2 O 3 powder. Crushing a sintered body produced by sintering a powder added with 5 to 2 parts by weight of Y 2 O 3 powder in a vacuum atmosphere at a temperature exceeding 1400 ° C. and less than 1700 ° C. It is characterized by.
[0006]
The highly corrosion-resistant refractory material according to the present invention is more preferably produced by sintering and pulverizing a material in which 0.5 to 1 part by weight of Y 2 O 3 powder is added. The vacuum atmosphere is preferably 10 −20 to 10 −5 atm. Furthermore, the sintering temperature is more preferably higher than 1500 ° C. and lower than 1700 ° C.
Examples of the high corrosion resistance refractory material to which the present invention is applied include aggregates in addition to binder materials for refractories.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, 25 parts by weight or more and 150 parts by weight or less of MgO powder is added to 100 parts by weight of Cr 2 O 3 powder, and 0.5 parts by weight or more and 2 parts by weight or less, preferably 0.5 parts by weight or more and 1 part by weight or less. preparing those obtained by adding the following Y 2 O 3 powder parts.
As the Cr 2 O 3 powder, those having an average particle diameter of 0.1 μm to 3 μm are suitable. This is because when the particle size is 0.1 μm, significant aggregation occurs in the powder, and when the particle size is 3 μm or more, the sinterability is lowered and the powder is not densified. As the MgO powder, those having an average particle diameter of 0.1 μm to 3 μm are suitable.
This is because when the particle size is 0.1 μm, significant aggregation occurs in the powder, and when the particle size is 3 μm or more, the sinterability is lowered and the powder is not densified. As the Y 2 O 3 powder, those having an average particle diameter of 0.1 μm to 3 μm are suitable.
It is because it will become difficult to disperse | distribute uniformly when a particle size is outside this range.
[0008]
The above-prepared product is sufficiently homogeneously mixed in an alcohol such as butanol, an organic solvent such as acetone, xylene and toluene.
The obtained mixture is dried and, for example, uniaxial molding at a pressure of 100 kgf / cm 2 and cold isostatic pressing at a pressure of 1000 kgf / cm 2 are performed to obtain a molded body.
[0009]
And the said molded object is sintered. As for the sintering atmosphere, ceramics are generally sintered at atmospheric pressure, but in order to carry out the present invention, a vacuum atmosphere is required.
The reason for this is that, at atmospheric pressure, Cr 2 O 3 oxidizes and becomes CrO 3 , which volatilizes and condenses with other particles inside the sintered body, so that small particles become coarse and the density of the sintered body decreases. Because it does. That is, in the present invention, by setting the vacuum atmosphere, particularly 10 −5 atm or less, the oxidation of Cr ions is prevented and the density of the sintered body is kept high. The degree of vacuum is preferably 10 −20 to 10 −5 atm, because when the degree of vacuum is extremely high, especially when it is less than 10 −20 atm, Cr ions may be reduced to metal chromium. This degree of vacuum is expressed by oxygen partial pressure.
[0010]
In the present invention, 0.5 to 2 parts by weight, preferably 0.5 to 1 part by weight of Y 2 O 3 powder is used as an auxiliary agent with respect to the total of Cr 2 O 3 and MgO. It is added. This auxiliary agent promotes the solid solution of Cr 2 O 3 and MgO, thereby helping to uniformly mix them, lowering the grain boundary energy and contributing to the sintering, and selectively corroding the grain boundary part. Suppress. This is because if the addition amount is less than 0.5 parts by weight, it is difficult to sufficiently reduce the grain boundary energy, and if it exceeds 2 parts by weight, selective corrosion of Y203 occurs and the corrosion resistance is impaired. .
[0011]
The sintering temperature should be 1400 ° C. or higher in order to increase the diffusion rate of atoms and facilitate the sintering, but if the temperature exceeds 1700 ° C., the sintering density tends to decrease. Therefore, it is desirable that the temperature be higher than 1400 ° C and lower than 1700 ° C. More preferably, the temperature is higher than 1500 ° C. and lower than 1700 ° C.
[0012]
The highly corrosion-resistant refractory material according to the present invention is obtained by crushing a sintered body. As a crushing method, it is preferable to crush until the particle size becomes 1000 μm or less by a jaw crusher, an impact crusher and a ball mill.
[0013]
【Example】
Example 1
A binder material was prepared as a highly corrosion resistant refractory material according to the present invention. A binder material by a conventional method was also prepared.
In the binder material according to the present invention, a powder having an average particle diameter of 0.2 μm was used as the Cr 2 O 3 powder, and a 0.3 μm powder was used as the MgO powder. A powder having an average particle size of 0.3 μm was used as the Y 2 O 3 powder. In addition, comparison was made with the present invention using a Cr 2 O 3 powder having an average particle size of 0.2 μm and an MgO powder having an average particle size of 0.25 μm as the binder material according to the conventional method.
[0014]
1 part by weight of Y 2 O 3 powder is added to 100 parts by weight of Cr 2 O 3 powder, and MgO powder is weighed to 100 parts by weight, and mixed with butyl alcohol in an organic solvent. For 120 hours. The obtained mixture was dried using a vacuum dryer at 80 ° C.
After uniaxial molding of the mixed powder pressure 100 kgf / cm 2, to obtain a molded perform cold isostatic pressing pressure 1000 kgf / cm 2. The molded body was sintered at 1200 ° C. to 1700 ° C. for 3 hours in an atmosphere having an oxygen partial pressure of 10 −8 atm.
[0015]
The binder material according to the conventional method, the added in butyl alcohol mixer to a MgO powder to 100 parts by weight were mixed for 120 hours with respect to the Cr 2 O 3 powder 100 parts by weight. After mixing, the mixture was dried using a vacuum dryer at 80 ° C., and then molded by the same method as described above, and sintered in a vacuum having an oxygen partial pressure of 10 −8 atm for 3 hours.
[0016]
The sintering temperature dependence of the sintered density of the Cr 2 O 3 -MgO-Y 2 O 3 and Cr 2 O 3 -MgO sintering was performed by conventional methods used in the binder material according to the present invention shown in Table 1, Table As shown in FIG. 1, the binder material according to the present invention provides a sintered density of 95% or more at a sintering temperature of 1400 ° C. Further, with a binder material according to the conventional method, a sintered density of 95% or more can be obtained at a sintering temperature of 1600 ° C. This improvement in sintered density is always recognized prior to the solid solution of Cr 2 O 3 and MgO, and a sintered density of 95% or more is sufficient for solid solution of Cr 2 O 3 and MgO. is necessary.
[0017]
[Table 1]
In order to obtain a binder material according to the present invention, a Cr 2 O 3 —MgO sintered body added with 1.0 part by weight of Y 2 O 3 powder, 45 parts by weight of SiO 2 , 32.5 parts by weight Table 2 shows the corrosion weight loss at 1600 ° C. for 1 hour in molten slag composed of CaO and 22.5 parts by weight of Al 2 O 3 . Table 1 also shows corrosion weight loss at 1600 ° C. for 1 hour in a molten slag having the same composition of a Cr 2 O 3 —MgO sintered body produced by a conventional method as a comparison.
[0019]
[Table 2]
In the sintered body used for the binder material according to the conventional method, the corrosion weight loss is about 500 μm, whereas in the sintered body used for the binder material according to the present invention, the corrosion weight loss is about 50 μm and exhibits high corrosion resistance. It is understood that the corrosion resistance of the binder material is improved because the solid solution of Cr 2 O 3 and MgO is promoted and the corrosion resistance to the slag of the sintering aid component of Y 2 O 3 is high.
[0021]
【The invention's effect】
As is apparent from the above description, according to the present invention, the material is homogeneous, and suitable for refractories suitable for refractories that are severely corroded by molten slag such as refuse incineration ash melting furnaces, nuclear reactor waste melting furnaces, etc. A highly corrosion-resistant refractory material such as a binder material is provided.
Claims (5)
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| EP1982965A1 (en) * | 2005-05-30 | 2008-10-22 | Refractory Intellectual Property GmbH & Co. KG | Refractory ceramic product |
| US8105683B2 (en) * | 2007-03-07 | 2012-01-31 | General Electric Company | Treated refractory material and methods of making |
| CN116161976B (en) * | 2023-04-24 | 2023-07-07 | 淄博富邦元进耐火材料科技有限公司 | Refractory material and preparation process thereof |
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