JP4345323B2 - Method for producing activated alumina molded body - Google Patents
Method for producing activated alumina molded body Download PDFInfo
- Publication number
- JP4345323B2 JP4345323B2 JP2003050753A JP2003050753A JP4345323B2 JP 4345323 B2 JP4345323 B2 JP 4345323B2 JP 2003050753 A JP2003050753 A JP 2003050753A JP 2003050753 A JP2003050753 A JP 2003050753A JP 4345323 B2 JP4345323 B2 JP 4345323B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- molded body
- water
- powder
- activated alumina
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Compositions Of Oxide Ceramics (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は活性アルミナ成形体の製造方法に関し、詳しくはマクロ細孔容積が大きく高ＢＥＴ比表面積の活性アルミナ成形体を容易に製造し得る方法に関する。
【０００２】
【従来の技術】
活性アルミナ成形体は、乾燥剤、吸着剤、触媒、触媒担体などとして有用であり、細孔半径０．３μｍ以上で外部と連通したマクロ細孔の容積が大きく、ＢＥＴ比表面積の高いものが望まれている。
【０００３】
かかるマクロ細孔の容積が大きく、ＢＥＴ比表面積も比較的大きな活性アルミナ成形体の製造方法として、特許文献１（特開昭４９−６００６号公報）および特許文献２（特開平８−２４５２８１号公報）には、再水和性アルミナ粉末および有機起孔剤を水と混練し、賦形し、焼成する方法が開示されており、有機起孔剤としては、繊維状有機物、ポリメタクリル酸エステルなどのような、焼成時に焼失し、また水を殆ど吸収しないものが開示されている。
【０００４】
しかし、かかる従来の製造方法では、マクロ細孔の容積を大きくしようとすると有機起孔剤の使用量を増やす必要があり、有機起孔剤の使用量を増やすと、得られる活性アルミナ成形体のＢＥＴ比表面積が小さくなり易いという問題があった。
【０００５】
【特許文献１】
特開昭４９−６００６号公報
【特許文献２】
特開平８−２４５２８１号公報
【０００６】
【発明が解決しようとする課題】
そこで本発明者は、大きなマクロ細孔容積を示し、高ＢＥＴ比表面積の活性アルミナ成形体を容易に製造し得る方法を開発するべく鋭意検討した結果、再水和性アルミナ粉末および中心粒子径５０〜５００μｍの吸水性樹脂粉末を混合し粉砕してブレーン比表面積が１００００〜１３５００ｃｍ2／ｇの混合粉砕物を得、これに水を加え、賦形し、再水和させ、焼成することとすれば、マクロ細孔容積が大きく、高ＢＥＴ比表面積の活性アルミナ成形体が容易に得られることを見出し、本発明に至った。
【０００７】
すなわち本発明は、ρ−アルミナを主成分とするアルミナ粉末を中心粒子径５０μｍ以上で吸水倍率が１００〜２００で、ρ−アルミナを主成分とするアルミナ粉末１００質量部に対して０．１質量部以上０．５質量部以下の吸水性樹脂粉末と混合し粉砕してブレーン比表面積が８０００ｃｍ 2 ／ｇ以上１３５００ｃｍ2／ｇ以下の混合粉砕物を得、得られた混合粉砕物に水を加え、賦形してρ−アルミナを主成分とするアルミナ粉末成形体を得、得られたρ−アルミナを主成分とするアルミナ粉末成形体を水蒸気と接触させてρ−アルミナを主成分とするアルミナ成形体を得、得られたρ−アルミナを主成分とするアルミナ成形体を焼成することを特徴とする活性アルミナ成形体の製造方法を提供するものである。
【０００８】
【発明の実施の形態】
本発明の製造方法では、先ず再水和性アルミナ粉末、吸水性樹脂粉末および水を混合して再水和性アルミナ粉末組成物を得る。
【０００９】
再水和性活性アルミナ粉末とは、水和し得るアルミナであって粉末状のものである。再水和性アルミナとしては、例えばρ相を主結晶相とするρ−アルミナ、非晶質の不定形アルミナなどが挙げられる。ρ−アルミナはχ相を含んでいてもよい。かかる再水和性アルミナ粉末の粒子径は好ましくは１０μｍ以上、１００μｍ以下程度、さらに好ましくは２０μｍ以上、８０μｍ以下程度である。
【００１０】
再水和性アルミナ粉末は、例えばギブサイト型水酸化アルミニウムを瞬間仮焼する方法により得ることができる。ギブサイト型水酸化アルミニウムはバイヤー法により工業的に得られる三水酸化アルミニウムであって、通常はナトリウム含有量が酸化物換算で０．０２〜１質量％程度のものを用いることができる。また、かかる再水和性アルミナ粉末は、市販のものから適宜選択して用いることもできる。
【００１１】
吸水性樹脂粉末は、水分を吸収して膨潤し得る樹脂の粉末であって、例えばポリアクリル酸塩系吸水性樹脂、ポリアルキレンオキサイド系吸水性樹脂、グラフトデンプン系吸水性樹脂、ポリビニルアルコール系吸水性樹脂、ビニルアセトアミド重合体系吸水性樹脂、ポリアスパラギン酸塩系吸水性樹脂、イソブチレン・無水マレイン酸共重合物金属塩系吸水性樹脂などの粉末が挙げられる。かかる吸水性樹脂の吸水倍率は通常１００以上２００以下程度である。
【００１２】
かかる吸水性樹脂としては中心粒子径が５０μｍ以上、好ましくは８０μｍ以上であり、通常５００μｍ以下、好ましくは２００μｍ以下程度のものが用いられる。中心粒子径が５０μｍ未満では、マクロ細孔が形成しにくくなる傾向にある。また、５００μｍを超えると、マクロ細孔の径が大きくなり過ぎて、得られる活性アルミナ成形体の機械的強度が低下する傾向にある。目的とする活性アルミナ成形体が、例えば触媒担体などとして用いられる場合には、不純物金属の含有量を少なくする点で、吸水性樹脂として金属含有量の少ないものを用いることが好ましい。
【００１３】
かかる吸水性樹脂粉末の使用量は、再水和性アルミナ粉末１００質量部に対して、より容易にマクロ細孔が形成される点で０．１質量部以上であることが好ましく、またＢＥＴ比表面積が大きくなり易い点で０．５質量部以下程度であることが好ましい。
【００１４】
本発明の製造方法では、かかる再水和性アルミナ粉末および吸水性樹脂粉末を混合粉砕する。混合粉砕は通常、乾燥状態で行なわれる。混合粉砕する方法は特に限定されるものではなく、例えばナフターミキサー、オムニミキサー、コンクリートミキサー、リボンミキサーなどの混合装置を用いても混合した後に、粉砕してもよいし、粉砕装置に再水和性アルミナ粉末および吸水性樹脂を投入して、混合しながら粉砕してもよい。粉砕装置としては、例えばボールミル、振動ミル、ジェットミル、流動媒体ミル、自由粉砕機、擂潰機などを用いることができる。また、混合粉砕はバッチ式で行なってもよいし、連続的に行なってもよいが、連続的に混合粉砕することで工業的に安価に混合粉砕することができて、好ましい。混合し粉砕することにより、通常は再水和性アルミナ粉末が粉砕されると同時に吸水性樹脂も粉砕される。
【００１５】
混合し粉砕することにより得られる混合粉砕物のブレーン比表面積は１３５００ｃｍ2／ｇ以下である。混合粉砕物のブレーン比表面積が１３５００ｃｍ2／ｇを超えると、得られる活性アルミナ成形体のマクロ細孔の容積が小さくなる傾向にある。また、８０００ｃｍ2／ｇ未満では、得られる活性アルミナ成形体の機械的強度が低下する傾向にあるため、８０００ｃｍ2／ｇ以上であることが好ましい。
【００１６】
混合粉砕物に水を加える。加える水の量は、吸水性樹脂粉末が飽和し得る程度であって、賦形し得る程度であり、再水和性アルミナ粉末および吸水性樹脂粉末の合計量１００質量部に対して通常は５０質量部以上、８０質量部以下程度である。
【００１７】
水と共に、添加剤を加えてもよい。添加剤としては、例えば非再水和性アルミナ粉末、例えばα−アルミナ粉末、アルミニウムの塩、シリカ、粘土、タルク、ベントナイト、ゼオライト、コーディエライト、チタニア、アルカリ金属の塩、アルカリ土類金属の塩、希土類金属の塩、ジルコニア、ムライト、シリカアルミナなどが挙げられる。
【００１８】
水を加えた後、賦形することで、再水和性アルミナ成形体を得る。水を加え、賦形するには、例えば混合し粉砕した後の混合粉砕物をマルメライザー、転動造粒機などの成形装置を用いて水を加えながら賦形してもよい。これらの成形装置を用い、水を加えながら造粒することで、球状の再水和性アルミナ成形体を得ることができる。
【００１９】
また、混合粉砕物に水を加えて混練したのち、押出成形法、金型による圧縮成形法などの通常の方法により賦形してもよい。賦形後の最水和性アルミナ粉末成形体の形状は、目的の活性アルミナ成形体の用途に応じて適宜選択され、例えば球状、円柱状、リング状、板状、ハニカム状、塊状などが挙げられる。
【００２０】
かくして得られた再水和性アルミナ粉末成形体を再水和させて再水和アルミナ成形体を得る。再水和させるには、例えば再水和性アルミナ粉末成形体を水蒸気と接触させればよい。再水和性アルミナ粉末成形体は通常、０℃以上、２００℃以下、より機械的強度に優れた活性アルミナ成形体が得られる点で、好ましくは８０℃以上で水蒸気と接触させる。接触させる時間は、用いた再水和性アルミナ粉末の種類、形状、粒子径、再水和性アルミナ粉末成形体の形状、大きさなどによって異なるが、例えば１分以上１週間以下程度である。再水和性アルミナ粉末成形体は水蒸気と接触することで、そのままの形状で再水和して再水和アルミナ成形体となる。
【００２１】
得られた再水和アルミナ成形体は、酸性水溶液と接触させてもよい。酸性水溶液と接触させることで、ナトリウムなどのアルカリ金属成分が溶出してナトリウム分の少ない活性アルミナ成形体を得ることができる。また、得られる活性アルミナ成形体の表面を酸性にすることができる。また、ランタンなどのランタノイド元素、バリウムなどのアルカリ土類金属、珪素化合物、セリウム化合物、ジルコニウム化合物などの水溶液と接触させてもよい。かかる水溶液と接触させることで、耐熱性に優れた活性アルミナ成形体を得ることができる。
【００２２】
得られた再水和アルミナ成形体を焼成する。焼成温度は通常３００℃以上１０００℃以下程度、好ましくは３５０℃以上８００℃以下程度であり、添加物として塩を用いた場合にはその分解温度以上の温度で焼成することが好ましい。焼成方法は特に限定されるものではなく、燃焼ガス、電気ヒーターによる間接加熱、遠赤外線による加熱などの通常の加熱方法で加熱することで焼成できる。
【００２３】
再水和アルミナ成形体には再水和において付着した水分が含まれていることもあるが、かかる水分を除去した後に焼成してもよい。水分を除去するには、例えば自然乾燥、熱風乾燥、真空乾燥などの通常の方法で乾燥すればよい。
【００２４】
かくして活性アルミナ成形体を得るが、得られた活性アルミナ成形体は、例えば細孔半径０．３μｍ以上で外部と連通したマクロ細孔の容積が０．０４ｃｍ3／ｇ以上０．２ｃｍ3／ｇ以下、ＢＥＴ比表面積が１００ｍ2／ｇ以上４００ｍ2／ｇ以下程度である。
【００２５】
かかる活性アルミナ成形体は、マクロ細孔容積が大きく、またＢＥＴ比表面積も高いので、そのままで、例えば吸着剤などとして用いることができる。また触媒担体としても有用であり、貴金属等の触媒成分を担持して触媒として用いることもできる。
【００２６】
【発明の効果】
本発明の製造方法によれば、細孔半径０．３μｍ以上のマクロ細孔の容積が大きく、ＢＥＴ比表面積も高い活性アルミナ成形体を容易に製造することができる。
【００２７】
【実施例】
以下、実施例によって本発明をより詳細に説明するが、本発明は係る実施例に限定されるものではない。
【００２８】
なお、各実施例において得た活性アルミナ成形体は、以下の方法で評価した。
マクロ細孔容積：水銀圧入法によって測定した細孔分布から、細孔半径０．３μｍ以上１００μｍ以下の細孔の容積を求めた。
ＢＥＴ比表面積：マウンテック社製ＢＥＴ比表面積測定装置を用いて測定した。中心粒子径：Ｌｅｅｄｓ ＆ Ｎｏｒｔｈｒｕｐ社製マイクロトラック粒度分布計を用いて質量基準で求めた。
ブレーン比表面積：島津製作所社製ブレーン比表面積測定装置「ＳＳ−１００」を用いて、恒圧空気式測定法により求めた。
充填密度：ＪＩＳ Ｈ １９０２に準拠して、資料をメスシリンダーに取り、タッピングを１００回行なった後の試料容積から求めた。
耐圧強度：試料１０粒の直径をマイクロメーターで測定した後、硬度試験機にて破壊強度を測定し、断面積あたりの強度を求め、平均値を求めた。
【００２９】
実施例１
バイヤー法により得たギブサイト型水酸化アルミニウムの粉末〔中心粒子径は４０μｍ、水分含有量は１質量％以下〕を７００℃の熱ガス気流中に投入して瞬間仮焼して、再水和性アルミナ粉末〔粒子径は２０μｍ〜１００μｍの範囲〕を得た。この再水和性アルミナ粉末の結晶系は、ρ相およびχ相であった。
【００３０】
上記で得た再水和性アルミナ粉末１００質量部を吸水性樹脂粉末〔クラレ社製「ＫＩゲル−２０１Ｋ」、中心粒子径は１２０μｍ、吸水倍率１８３倍〕０．３質量部とナフターミキサーを用いて１時間かけて混合したのち、振動ボールミルを用いて粉砕した。粉砕後の混合粉砕物のブレーン比表面積は１３０００ｃｍ2／ｇであった。直径１ｍの皿型造粒機を用いて上記で得た粉砕物に水をスプレーしながら加えて造粒して、直径１〜３ｍｍの球状の再水和性アルミナ粉末成形体を得た。得られた再水和性アルミナ粉末成形体をオートクレーブ中で大気圧下に１０５℃で飽和水蒸気を含む空気と４時間接触させて再水和アルミナ成形体を得た。得られた再水和アルミナ成形体をアルミナ製ルツボに入れ、電気炉で４００℃に昇温し、同温度で２時間保持して焼成して、活性アルミナ成形体を得た。
【００３１】
得られた活性アルミナ成形体のマクロ細孔容積は０．０６ｃｍ3／ｇ、ＢＥＴ比表面積は２７８ｍ2／ｇであり、充填密度は０．７１ｇ／ｃｍ3、耐圧強度は１４４０Ｎ／ｃｍ2であった。
【００３２】
比較例１
吸水性樹脂粉末を用いない以外は実施例１と同様に操作して、活性アルミナ成形体を得た。得られた活性アルミナ成形体のマクロ細孔容積は０．０３ｃｍ3／ｇ、ＢＥＴ比表面積は２７０ｍ2／ｇであり、充填密度は０．８１ｇ／ｃｍ3、耐圧強度は１７１０Ｎ／ｃｍ2であった。
【００３３】
比較例２
吸水性樹脂粉末〔ＫＩゲル２０１Ｋ〕に代えて、吸水性樹脂粉末〔クラレ社製「ＫＩゲル−２０１−Ｆ２」、中心粒子径は１８μｍ、吸水倍率１８４倍〕０．３質量部を用いる以外は実施例１と同様に操作して、活性アルミナ成形体を得た。得られた活性アルミナ成形体のマクロ細孔容積は０．０２ｃｍ3／ｇ、ＢＥＴ比表面積は２７５ｍ2／ｇであり、充填密度は０．７８ｇ／ｃｍ3、耐圧強度は１７７０Ｎ／ｃｍ2であった。
【００３４】
比較例３
ブレーン比表面積が１４００００ｃｍ2／ｇとなるまで粉砕した以外は実施例１と同様に操作して、活性アルミナ成形体を得た。得られた活性アルミナ成形体のマクロ細孔容積は０．０３ｃｍ3／ｇ、ＢＥＴ比表面積は３０８ｍ2／ｇであり、充填密度は０．７７ｇ／ｃｍ3、耐圧強度は１３２０Ｎ／ｃｍ2であった。
【００３５】
実施例２
吸水性樹脂粉末の使用量を０．４質量部とし、再水和アルミナ成形体の焼成温度を８５０℃とする以外は実施例１と同様に操作して、活性アルミナ成形体を得た。得られた活性アルミナ成形体のマクロ細孔容積は０．０７ｃｍ3／ｇ、ＢＥＴ比表面積は１０６ｃｍ3／ｇであり、充填密度は０．６７ｇ／ｃｍ3、耐圧強度は５９０Ｎ／ｃｍ2であった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an activated alumina molded body, and more particularly to a method for easily producing an activated alumina molded body having a large macropore volume and a high BET specific surface area.
[0002]
[Prior art]
The activated alumina molded body is useful as a desiccant, adsorbent, catalyst, catalyst support, etc., and has a pore radius of 0.3 μm or more, a large macropore volume communicating with the outside, and a high BET specific surface area. It is rare.
[0003]
Patent Document 1 (Japanese Patent Laid-Open No. 49-6006) and Patent Document 2 (Japanese Patent Laid-Open No. 8-245281) are methods for producing such an activated alumina molded body having a large macropore volume and a relatively large BET specific surface area. ) Discloses a method in which a rehydratable alumina powder and an organic pore-forming agent are kneaded with water, shaped and fired. Examples of the organic pore-forming agent include fibrous organic substances, polymethacrylic acid esters, and the like. And the like that are burned out during firing and hardly absorb water.
[0004]
However, in such a conventional production method, it is necessary to increase the amount of the organic pore-forming agent when trying to increase the volume of the macropores. There has been a problem that the BET specific surface area tends to be small.
[0005]
[Patent Document 1]
JP 49-6006 A [Patent Document 2]
Japanese Patent Laid-Open No. 8-245281
[Problems to be solved by the invention]
Therefore, the present inventor has intensively studied to develop a method capable of easily producing an activated alumina molded body having a large macropore volume and having a high BET specific surface area. As a result, the rehydratable alumina powder and the center particle diameter of 50 are obtained. A mixed pulverized product having a Blaine specific surface area of 10,000 to 13500 cm 2 / g is obtained by mixing and pulverizing a water-absorbing resin powder of ˜500 μm, adding water to this, shaping, rehydrating, and firing. For example, it has been found that an activated alumina molded body having a large macropore volume and a high BET specific surface area can be easily obtained, and the present invention has been achieved.
[0007]
That is, in the present invention, an alumina powder mainly composed of ρ-alumina has a center particle diameter of 50 μm or more , a water absorption ratio of 100 to 200, and 0.1 mass relative to 100 parts by mass of the alumina powder mainly composed of ρ-alumina. And mixed with a water-absorbing resin powder of not less than 0.5 parts by mass and pulverized to obtain a mixed pulverized product having a Blaine specific surface area of not less than 8000 cm 2 / g and not more than 13500 cm 2 / g, and water is added to the obtained mixed pulverized product Then, an alumina powder molded body containing ρ-alumina as a main component is obtained by shaping, and the resulting alumina powder molded body containing ρ-alumina as a main component is brought into contact with water vapor to produce alumina as a main component of ρ-alumina. An object of the present invention is to provide a method for producing an activated alumina molded body characterized by obtaining a molded body and firing the obtained alumina molded body mainly composed of ρ-alumina .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the production method of the present invention, first, a rehydratable alumina powder, a water absorbent resin powder and water are mixed to obtain a rehydratable alumina powder composition.
[0009]
The rehydratable activated alumina powder is a hydrated alumina powder. Examples of the rehydratable alumina include ρ-alumina having a ρ phase as a main crystal phase, and amorphous amorphous alumina. ρ-alumina may contain a χ phase. The particle size of the rehydratable alumina powder is preferably about 10 μm to 100 μm, more preferably about 20 μm to 80 μm.
[0010]
The rehydratable alumina powder can be obtained, for example, by a method of instantaneous calcination of gibbsite type aluminum hydroxide. Gibbsite-type aluminum hydroxide is aluminum trihydroxide that is industrially obtained by the Bayer method, and usually has a sodium content of about 0.02 to 1% by mass in terms of oxide. Such rehydratable alumina powder can be appropriately selected from commercially available ones.
[0011]
The water-absorbing resin powder is a resin powder that can swell by absorbing moisture, and is, for example, a polyacrylate water-absorbing resin, a polyalkylene oxide water-absorbing resin, a graft starch-based water-absorbing resin, or a polyvinyl alcohol-based water absorbing resin. Powders such as water-soluble resin, vinylacetamide polymer-based water-absorbent resin, polyaspartate-based water-absorbent resin, isobutylene / maleic anhydride copolymer metal salt-based water-absorbent resin. The water absorption ratio of such a water absorbent resin is usually about 100 or more and 200 or less.
[0012]
As such a water-absorbent resin, those having a center particle diameter of 50 μm or more, preferably 80 μm or more, and usually 500 μm or less, preferably about 200 μm or less are used. If the center particle diameter is less than 50 μm, macropores tend to be difficult to form. On the other hand, if it exceeds 500 μm, the diameter of the macropores becomes too large, and the mechanical strength of the obtained activated alumina molded product tends to decrease. When the target activated alumina molded body is used as, for example, a catalyst carrier, it is preferable to use a water-absorbent resin having a low metal content in order to reduce the content of impurity metals.
[0013]
The amount of the water-absorbent resin powder used is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the rehydratable alumina powder in terms of more easily forming macropores. It is preferably about 0.5 parts by mass or less from the viewpoint of increasing the surface area.
[0014]
In the production method of the present invention, the rehydratable alumina powder and the water absorbent resin powder are mixed and ground. The mixing and pulverization is usually performed in a dry state. The method of mixing and pulverizing is not particularly limited. For example, the mixing and pulverization may be performed using a mixing apparatus such as a naphther mixer, an omni mixer, a concrete mixer, or a ribbon mixer, and may be pulverized or re-watered in the pulverizing apparatus. You may grind | pulverize, mixing a compatible alumina powder and a water absorbing resin. As the pulverizer, for example, a ball mill, a vibration mill, a jet mill, a fluid medium mill, a free pulverizer, a crusher, or the like can be used. Further, the mixing and pulverization may be performed batchwise or continuously, but continuous mixing and pulverization is preferable because it can be industrially inexpensively mixed and pulverized. By mixing and pulverizing, the rehydratable alumina powder is usually pulverized and the water-absorbent resin is also pulverized.
[0015]
The Blaine specific surface area of the mixed pulverized product obtained by mixing and pulverizing is 13500 cm 2 / g or less. When the Blaine specific surface area of the mixed pulverized product exceeds 13500 cm 2 / g, the volume of macropores of the obtained activated alumina compact tends to be small. Further, if it is less than 8000 cm 2 / g, the mechanical strength of the obtained activated alumina molded product tends to decrease, and therefore it is preferably 8000 cm 2 / g or more.
[0016]
Add water to the mixed grind. The amount of water added is such that the water-absorbent resin powder can be saturated and can be shaped, and is usually 50 with respect to 100 parts by mass of the total amount of the rehydratable alumina powder and the water-absorbent resin powder. It is about not less than 80 parts by mass.
[0017]
An additive may be added together with water. Examples of the additive include non-rehydratable alumina powder such as α-alumina powder, aluminum salt, silica, clay, talc, bentonite, zeolite, cordierite, titania, alkali metal salt, alkaline earth metal Examples thereof include salts, rare earth metal salts, zirconia, mullite, and silica alumina.
[0018]
After adding water, shaping is performed to obtain a rehydratable alumina molded body. In order to add water and shape, for example, the mixed and pulverized product after mixing and pulverization may be shaped while adding water using a molding apparatus such as a malmerizer or a tumbling granulator. By using these molding apparatuses and granulating while adding water, a spherical rehydratable alumina molded body can be obtained.
[0019]
Further, after adding and kneading water to the mixed pulverized product, it may be shaped by an ordinary method such as an extrusion molding method or a compression molding method using a mold. The shape of the most hydrated alumina powder molded body after shaping is appropriately selected according to the intended use of the activated alumina molded body, and examples thereof include a spherical shape, a cylindrical shape, a ring shape, a plate shape, a honeycomb shape, and a lump shape. It is done.
[0020]
The rehydratable alumina powder compact thus obtained is rehydrated to obtain a rehydrated alumina compact. In order to rehydrate, for example, the rehydratable alumina powder compact may be brought into contact with water vapor. The rehydratable alumina powder molded body is usually brought into contact with water vapor at 80 ° C. or higher in that an activated alumina molded body having a mechanical strength of 0 ° C. or higher and 200 ° C. or lower is obtained. The contact time varies depending on the type, shape, particle diameter, shape and size of the rehydrated alumina powder molded body used, and is, for example, about 1 minute to 1 week. When the rehydratable alumina powder compact is brought into contact with water vapor, it is rehydrated as it is to form a rehydrated alumina compact.
[0021]
The obtained rehydrated alumina molded body may be brought into contact with an acidic aqueous solution. By contacting with an acidic aqueous solution, an alkali metal component such as sodium is eluted, and an activated alumina molded body having a small amount of sodium can be obtained. Moreover, the surface of the obtained activated alumina molded body can be made acidic. Further, it may be contacted with an aqueous solution of a lanthanoid element such as lanthanum, an alkaline earth metal such as barium, a silicon compound, a cerium compound, or a zirconium compound. By bringing into contact with such an aqueous solution, an activated alumina molded body having excellent heat resistance can be obtained.
[0022]
The obtained rehydrated alumina molded body is fired. The firing temperature is usually about 300 ° C. or higher and about 1000 ° C. or lower, preferably about 350 ° C. or higher and about 800 ° C. or lower. When a salt is used as an additive, firing is preferably performed at a temperature higher than the decomposition temperature. The firing method is not particularly limited, and the firing can be performed by heating with a normal heating method such as combustion gas, indirect heating with an electric heater, or heating with far infrared rays.
[0023]
The rehydrated alumina molded body may contain water adhering to the rehydration, but may be fired after removing the water. In order to remove moisture, it may be dried by an ordinary method such as natural drying, hot air drying, or vacuum drying.
[0024]
Thus although obtain an active alumina compact, the resulting activated alumina formed body, for example, the volume of macro pores communicates with the outside at a pore radius 0.3μm or 0.04 cm 3 / g or more 0.2 cm 3 / g Hereinafter, the BET specific surface area is about 100 m 2 / g or more and 400 m 2 / g or less.
[0025]
Such an activated alumina molded body has a large macropore volume and a high BET specific surface area, so that it can be used as it is, for example, as an adsorbent. It is also useful as a catalyst carrier and can be used as a catalyst by supporting a catalyst component such as a noble metal.
[0026]
【The invention's effect】
According to the production method of the present invention, an activated alumina molded body having a large macropore volume with a pore radius of 0.3 μm or more and a high BET specific surface area can be easily produced.
[0027]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the Example which concerns.
[0028]
In addition, the activated alumina molded object obtained in each Example was evaluated with the following method.
Macropore volume: From the pore distribution measured by mercury porosimetry, the volume of pores having a pore radius of 0.3 μm or more and 100 μm or less was determined.
BET specific surface area: Measured using a BET specific surface area measuring device manufactured by Mountec. Central particle size: Determined on a mass basis using a Microtrac particle size distribution meter manufactured by Lees & Northrup.
Blaine specific surface area: The specific surface area was determined by a constant-pressure air measurement method using a branes specific surface area measuring device “SS-100” manufactured by Shimadzu Corporation.
Filling density: Based on JIS H 1902, a sample was taken from a measuring cylinder and obtained from the sample volume after tapping 100 times.
Pressure resistance: After measuring the diameter of 10 samples with a micrometer, the fracture strength was measured with a hardness tester, the strength per cross-sectional area was determined, and the average value was determined.
[0029]
Example 1
Gibbsite-type aluminum hydroxide powder obtained by the Bayer method (center particle diameter is 40 μm, water content is 1% by mass or less) is poured into a hot gas stream at 700 ° C. An alumina powder (particle diameter in the range of 20 μm to 100 μm) was obtained. The crystal system of this rehydratable alumina powder was a ρ phase and a χ phase.
[0030]
100 parts by mass of the rehydratable alumina powder obtained above was mixed with 0.3 parts by mass of a water-absorbent resin powder [Kuraray Co., Ltd. “KI Gel-201K”, the center particle size was 120 μm, and the water absorption was 183 times] and a naphther mixer. After mixing for 1 hour, the mixture was pulverized using a vibration ball mill. The mixed pulverized product after pulverization had a Blaine specific surface area of 13000 cm 2 / g. Using a 1 m diameter dish granulator, water was sprayed onto the pulverized product obtained above and granulated to obtain a spherical rehydratable alumina powder molded body having a diameter of 1 to 3 mm. The obtained rehydratable alumina powder compact was brought into contact with air containing saturated water vapor at 105 ° C. under atmospheric pressure for 4 hours in an autoclave to obtain a rehydrated alumina compact. The obtained rehydrated alumina molded body was put in an alumina crucible, heated to 400 ° C. in an electric furnace, held at the same temperature for 2 hours and fired to obtain an activated alumina molded body.
[0031]
The obtained activated alumina compact had a macropore volume of 0.06 cm 3 / g, a BET specific surface area of 278 m 2 / g, a packing density of 0.71 g / cm 3 , and a pressure strength of 1440 N / cm 2. It was.
[0032]
Comparative Example 1
An activated alumina molded body was obtained in the same manner as in Example 1 except that the water absorbent resin powder was not used. The obtained activated alumina molded body had a macropore volume of 0.03 cm 3 / g, a BET specific surface area of 270 m 2 / g, a packing density of 0.81 g / cm 3 , and a pressure strength of 1710 N / cm 2. It was.
[0033]
Comparative Example 2
Instead of the water-absorbent resin powder [KI gel 201K], a water-absorbent resin powder [Kuraray Co., Ltd. "KI gel-201-F2", the center particle diameter is 18 μm, the water absorption magnification is 184 times] is used except 0.3 parts by mass. By operating in the same manner as in Example 1, an activated alumina molded body was obtained. The obtained activated alumina molded body had a macropore volume of 0.02 cm 3 / g, a BET specific surface area of 275 m 2 / g, a packing density of 0.78 g / cm 3 , and a pressure strength of 1770 N / cm 2. It was.
[0034]
Comparative Example 3
An activated alumina molded body was obtained in the same manner as in Example 1 except for crushing until the specific surface area of the brane was 140,000 cm 2 / g. The obtained activated alumina molded body had a macropore volume of 0.03 cm 3 / g, a BET specific surface area of 308 m 2 / g, a packing density of 0.77 g / cm 3 , and a pressure strength of 1320 N / cm 2. It was.
[0035]
Example 2
An activated alumina molded body was obtained in the same manner as in Example 1 except that the amount of water-absorbent resin powder used was 0.4 parts by mass and the firing temperature of the rehydrated alumina molded body was 850 ° C. The resulting macro pore volume of activated alumina formed body is 0.07cm 3 / g, BET specific surface area of 106cm 3 / g, a packing density of 0.67 g / cm 3, compressive strength is 590N / cm 2 met It was.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003050753A JP4345323B2 (en) | 2003-02-27 | 2003-02-27 | Method for producing activated alumina molded body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003050753A JP4345323B2 (en) | 2003-02-27 | 2003-02-27 | Method for producing activated alumina molded body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004256366A JP2004256366A (en) | 2004-09-16 |
| JP4345323B2 true JP4345323B2 (en) | 2009-10-14 |
Family
ID=33116083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003050753A Expired - Fee Related JP4345323B2 (en) | 2003-02-27 | 2003-02-27 | Method for producing activated alumina molded body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4345323B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108409309A (en) * | 2018-05-21 | 2018-08-17 | 洛阳利尔中晶光伏材料有限公司 | A kind of production method of Reactive alumina |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007001836A (en) * | 2005-06-27 | 2007-01-11 | Ngk Insulators Ltd | Method of manufacturing honeycomb structure |
| JP6901720B2 (en) * | 2017-02-28 | 2021-07-14 | 住友化学株式会社 | Particles for laminated molding, molded body, and manufacturing method of molded body |
| EP3760602A4 (en) * | 2018-02-28 | 2021-11-17 | Sumitomo Chemical Company Limited | Particle composition |
| CN109384458A (en) * | 2018-10-26 | 2019-02-26 | 湖北斯曼新材料股份有限公司 | A kind of green compact calcining preparation method and applications of active alpha-alumina powder |
| CN112028612B (en) * | 2020-09-02 | 2022-07-19 | 江苏苏嘉集团新材料有限公司 | Magnesia carbon brick applying reinforcing material |
-
2003
- 2003-02-27 JP JP2003050753A patent/JP4345323B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108409309A (en) * | 2018-05-21 | 2018-08-17 | 洛阳利尔中晶光伏材料有限公司 | A kind of production method of Reactive alumina |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004256366A (en) | 2004-09-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU1830050C (en) | Pressed article on the base of pyrogenic silicium dioxide and method for its production | |
| JP5168498B2 (en) | Porous molded body, method for producing the same, catalyst carrier and catalyst | |
| US20150158760A1 (en) | Porous glass ceramic composition and method for manufacturing the same | |
| JP3381948B2 (en) | Method for producing highly active calcium oxide porous body | |
| JPH0674170B2 (en) | Pressed product based on silicon dioxide obtained by thermal decomposition method, production method thereof, and catalyst carrier and catalyst comprising the pressed product | |
| JP4345323B2 (en) | Method for producing activated alumina molded body | |
| JPH0383813A (en) | Production of fine alpha-alumina powder | |
| EP1262236B1 (en) | Method for producing alpha-alumina formed body | |
| RU2076851C1 (en) | Molded porous product made of pyrogenic titanium dioxide, and process for manufacturing said product | |
| JP2009023848A (en) | Method for producing magnesia spinel molded article | |
| US6962684B2 (en) | Activated alumina formed body and method for producing the same | |
| JPS6234685B2 (en) | ||
| JPH11240777A (en) | Alpha-alumina porous aggregated sintered compact, its production and use thereof | |
| JP4512972B2 (en) | Activated alumina compact | |
| JPH09188553A (en) | Hydraulic alumina and its production | |
| JP4285113B2 (en) | Catalyst for producing dimethyl ether and method for producing dimethyl ether using the same | |
| JP3680342B2 (en) | Method for producing transition alumina molded body | |
| CN108083789A (en) | Porous mullite ceramics and preparation method thereof | |
| JPH0248484B2 (en) | ||
| JP4337419B2 (en) | Non-rehydratable activated alumina powder and activated alumina molded body and resin composition using the same | |
| JP3381226B2 (en) | How to remove carbon dioxide from exhaust gas | |
| JP3603570B2 (en) | Method for producing transition alumina molded body | |
| JP2005263529A (en) | Method for producing activated alumina having low alkali content | |
| RU2527259C2 (en) | Catalyst of obtaining element sulphur in claus process, method of its preparation and method of carrying out claus process | |
| JPH01320277A (en) | Porous body of mgo-al2o3 spinel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20060113 |
|
| RD05 | Notification of revocation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7425 Effective date: 20080129 |
|
| RD05 | Notification of revocation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7425 Effective date: 20080512 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20081201 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20081201 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090414 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20090519 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20090623 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090706 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120724 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120724 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130724 Year of fee payment: 4 |
|
| LAPS | Cancellation because of no payment of annual fees |