JP2004323257A - High-purity zirconium hydroxide with high specific surface area, zirconium oxide and production method therefor, and molded product - Google Patents
High-purity zirconium hydroxide with high specific surface area, zirconium oxide and production method therefor, and molded product Download PDFInfo
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- JP2004323257A JP2004323257A JP2003116599A JP2003116599A JP2004323257A JP 2004323257 A JP2004323257 A JP 2004323257A JP 2003116599 A JP2003116599 A JP 2003116599A JP 2003116599 A JP2003116599 A JP 2003116599A JP 2004323257 A JP2004323257 A JP 2004323257A
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- IVORCBKUUYGUOL-UHFFFAOYSA-N 1-ethynyl-2,4-dimethoxybenzene Chemical compound COC1=CC=C(C#C)C(OC)=C1 IVORCBKUUYGUOL-UHFFFAOYSA-N 0.000 title claims abstract description 75
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 title claims abstract description 24
- 229910001928 zirconium oxide Inorganic materials 0.000 title claims abstract description 22
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 230000032683 aging Effects 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000003054 catalyst Substances 0.000 claims abstract description 17
- 150000002500 ions Chemical class 0.000 claims abstract description 10
- 238000002441 X-ray diffraction Methods 0.000 claims abstract description 9
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 230000001747 exhibiting effect Effects 0.000 claims abstract 2
- 238000005406 washing Methods 0.000 claims description 12
- 238000001354 calcination Methods 0.000 claims description 7
- 229910052726 zirconium Inorganic materials 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 5
- 229910021512 zirconium (IV) hydroxide Inorganic materials 0.000 claims description 4
- -1 zirconium ions Chemical class 0.000 claims description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 abstract description 20
- 239000007858 starting material Substances 0.000 abstract description 4
- 238000004140 cleaning Methods 0.000 abstract description 3
- GBNDTYKAOXLLID-UHFFFAOYSA-N zirconium(4+) ion Chemical compound [Zr+4] GBNDTYKAOXLLID-UHFFFAOYSA-N 0.000 abstract 1
- ATYZRBBOXUWECY-UHFFFAOYSA-N zirconium;hydrate Chemical compound O.[Zr] ATYZRBBOXUWECY-UHFFFAOYSA-N 0.000 abstract 1
- 239000000047 product Substances 0.000 description 17
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 14
- 239000002244 precipitate Substances 0.000 description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- CMOAHYOGLLEOGO-UHFFFAOYSA-N oxozirconium;dihydrochloride Chemical compound Cl.Cl.[Zr]=O CMOAHYOGLLEOGO-UHFFFAOYSA-N 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 4
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 4
- 235000011130 ammonium sulphate Nutrition 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000005070 ripening Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 description 4
- 239000007921 spray Substances 0.000 description 3
- 150000003754 zirconium Chemical class 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- ZXAUZSQITFJWPS-UHFFFAOYSA-J zirconium(4+);disulfate Chemical compound [Zr+4].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZXAUZSQITFJWPS-UHFFFAOYSA-J 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 239000012776 electronic material Substances 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000035800 maturation Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 1
- QRTRRDMHGTZPBF-UHFFFAOYSA-L oxygen(2-);zirconium(4+);sulfate Chemical compound [O-2].[Zr+4].[O-]S([O-])(=O)=O QRTRRDMHGTZPBF-UHFFFAOYSA-L 0.000 description 1
- 238000005504 petroleum refining Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- DUNKXUFBGCUVQW-UHFFFAOYSA-J zirconium tetrachloride Chemical compound Cl[Zr](Cl)(Cl)Cl DUNKXUFBGCUVQW-UHFFFAOYSA-J 0.000 description 1
- XJUNLJFOHNHSAR-UHFFFAOYSA-J zirconium(4+);dicarbonate Chemical compound [Zr+4].[O-]C([O-])=O.[O-]C([O-])=O XJUNLJFOHNHSAR-UHFFFAOYSA-J 0.000 description 1
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、高比表面積を有する水酸化ジルコニウム、酸化ジルコニウム、その製造方法、及び成形製品に関する。特に本発明は、Ｘ線回折パターンが非晶質の特徴を示す水酸化ジルコニウムとその製造方法及びそれを基に製造される酸化ジルコニウム並びに成形製品に関する。なお、本明細書において「水酸化ジルコニウム」とは、水酸化ジルコニウム及び水和ジルコニアと称されるものの総称である。
【０００２】
【従来の技術】
酸化ジルコニウムは高い耐熱性、特異な結晶構造を有し、固体電解質、石油精製触媒、自動車排ガス触媒、電子部品など機能性の高い商品の素材として近年需要が増大している。特に触媒分野に使用されるものは接触面積増大のために比表面積の大きいものが要望されている。
【０００３】
このような酸化ジルコニウムは、ジルコニウム塩の水溶液から中和法、加水分解法などによって生成させた水酸化ジルコニウムを洗浄、脱水し、これを仮焼することにより製造されている。そして、その比表面積の増大を図るための手段として、特許文献１には、ジルコニウム塩水溶液をアンモニアと混合して得られる沈殿生成物を、乾燥及びか焼する方法において、乾燥前に水溶液相中の該沈殿物を０〜３００℃で熟成し、かつ２００乃至６００℃でか焼する巨大比表面積を有する単斜晶系二酸化ジルコニウムの製造方法が開示されている。
【０００４】
また、非特許文献１は、高比表面積ジルコニアの沈殿物の生成−沈殿剤と熟成の影響についてと題する論文であるが、これには水酸化物を１００℃で熟成することにより高比表面積ジルコニアを製造する際に、沈殿物の生成前駆体、中和液などから持ち込まれるイオンと共に熟成を行うと格子中にイオン組み込みが起こりやすく高純度な物が製造できないことが指摘されている。
【０００５】
【特許文献１】
特開平１０−３３０１１６号公報
【非特許文献１】
ＣＨＵＡＨ Ｇ Ｋ、Ａｐｐｌｉｅｄ Ｃａｔａｌｙｓｉｓ Ａ Ｇｅｎｅｒａｌ Ｖｏｌ．１６３（１９９７）ｐ．２６１−２７３
【０００６】
【発明が解決しようとする課題】
しかしながら、この特許文献１記載の手段では、その実施例１によれば純粋な単斜晶系相の二酸化ジルコニアを得るためには、熟成温度を９０℃としたとき４３２時間熟成する必要があることが示されている。一方、実施例３によれば、熟成温度を１３５℃とすれば熟成時間を２４時間と短縮できることが示されている。これらの実施例によれば、特許文献１記載の手段は、熟成のため膨大な時間がかかるか、あるいは時間を短縮しようとすれば、高価で大量処理が困難な圧力容器を必要とするという問題がある。さらに、非特許文献１に示されているように、純度が高い物が製造し難いという問題もある。
【０００７】
本発明は、このような従来技術の有する問題点を解決することを目的とし、高比表面積の二酸化ジルコニウムの出発素材となる水酸化ジルコニウムを工業規模で安価に製造すること、しかも極めて高純度で高比表面積を有するものとすること、併せてかかる水酸化ジルコニウムを出発素材として高比表面積を有する酸化ジルコニウムを製造すること、さらにかかる酸化ジルコニウムを用いて成形製品、特に触媒や触媒担体を製造する手段を提供するものである。
【０００８】
【課題を解決するための手段】
本発明者は水酸化ジルコニウム又は含水ジルコニアを洗浄して夾雑イオンの少ない状態としその状態で熟成を行えば、非晶質で高比表面積を有する水酸化ジルコニウムが得られることを知見し、この知見を基に本発明を完成したものである。
【０００９】
本発明の水酸化ジルコニウムは、Ｘ線回折パターンが非晶質の特徴を示し、かつ２５０ｍ２／ｇ以上のＢＥＴ表面積を有するものである。
【００１０】
かかる水酸化ジルコニウムは、水酸化ジルコニウム又は含水ジルコニアを得る段階、得られた水酸化ジルコニウムを水洗して夾雑イオンの合計含有量をジルコニウムイオンに対し３ｍｏｌ％以下とする段階、前記段階で水洗された水酸化ジルコニウムを熟成する段階、を順次行うことによって製造できる。その際、上記熟成を５０℃以上の温度で２〜４８時間行うことが望ましい。
【００１１】
上記により得られた水酸化ジルコニウムは４００〜１２００℃で仮焼することにより高比表面積を有する酸化ジルコニウムとすることができ、その特性は単斜晶が９５％以上でかつ比表面積が３〜１５０ｍ２／ｇである。ここで単斜晶率νｍは、
【００１２】
上記の水酸化ジルコニウム、又は酸化ジルコニウムは加圧成形して成形製品として利用することができ、特に、触媒又は触媒担体として好適に利用できる。これらの成形製品は酸化ジルコニウム、酸化ジルコニウムを質量比で５０％以上含有するものとすることが好適である。
【００１３】
【発明の実施の形態】
以下、本発明に係る非晶質で高比表面積を有する水酸化ジルコニウムの製造方法について具体的に説明し、併せて得られた水酸化ジルコニウムの特徴、用途について説明する。
【００１４】
本発明に係る非晶質で高比表面積を有する水酸化ジルコニウムを製造するための出発材料は、公知の湿式法で製造された水酸化ジルコニウム（含水ジルコニア）である。このような水酸化ジルコニウム（含水ジルコニア）としては、▲１▼通常工業的に入手しうるオキシ塩化ジルコニウム、硝酸ジルコニウム、硫酸ジルコニウム、炭酸ジルコニウムなど水もしくは酸に可溶なジルコニウム塩を溶解させた後にアンモニア水、水酸化ナトリウム水、水酸化カリウム水などアルカリで中和沈殿させたもの、▲２▼一旦塩基性硫酸ジルコニウムなど中間体を経由させた後に中和沈殿させたもの、または▲３▼オキシ塩化ジルコニウム、硝酸ジルコニウム、硫酸ジルコニウムなどを加水分解した後にアンモニア水、水酸化ナトリウム水、水酸化カリウム水などアルカリで中和させたものなどを利用することができる。
【００１５】
本発明ではかかる公知の手段によって製造された水酸化ジルコニウムに対し、まず水洗を行い夾雑イオンの合計含有量をジルコニウムイオンに対し３ｍｏｌ％以下とする。この水洗は、上記水酸化ジルコニウムに対し洗浄用の清水を加え、フィルタープレス、遠心分離器、デカンターなど公知の機器を利用して夾雑イオンを洗浄水とともに洗い流すことによって行う。なお、この洗浄に当たっては向流多段洗浄などの方法を用いることができ、それによって水の有効利用を図ることができる。
【００１６】
洗浄は夾雑イオンの合計含有量がジルコニウムイオンに対し３ｍｏｌ％以下、好ましくは１ｍｏｌ％以下となるまで繰り返し行う。所定の純度になるまで洗浄を十分行わないと次の熟成工程で熟成に要する時間が長くなる。また、熟成中にジルコニウムが不純物イオンで置換され純度の高い水酸化ジルコニウムが得られにくくなる。
【００１７】
次に、このようにして夾雑イオン含有量を十分低減せしめた水酸化ジルコニウムを熟成する。この熟成は、前記水洗された水酸化ジルコニウムを５０℃以上、望ましくは７０℃以上の温度に加熱し、２〜４８時間保持することによって行う。一般的には、上記水酸化ジルコニウムに清水（電気伝導度：５００μＳ／ｃｍ以下又は全溶解物質（ＴＤＳ）≦３００ｐｐｍのもの）を加え質量比で水酸化ジルコニウムを５％以上を含有するスラリーとし、これを電気ヒーター、蒸気などの適当な加熱器を使用して上記温度に加熱することによって行うが、脱水されたケーキ状の水酸化ジルコニウムを直接加熱することによっても目的を果たすことができる。加熱温度が低い場合あるいは保持時間が短い場合は熟成が十分に進行せず、高比表面積の水酸化ジルコニウムを得ることができなくなる。
【００１８】
このようにして熟成された水酸化ジルコニウムは、熟成がスラリー状態で行われた場合には脱水後、ケーキ状態で行われた場合には直ちに、乾燥して製品とされる。乾燥は棚式乾燥機、スプレードライヤなど通常の乾燥機を用いることができるが、乾燥温度が４００℃を超えると水酸化ジルコニウム（Ｚｒ（ＯＨ）４）が脱水されてジルコニア（ＺｒＯ２）になり、結晶化するため乾燥温度は４００℃以下とする。
【００１９】
このようにして得られた水酸化ジルコニウムは、化学式（Ｚｒ（ＯＨ）４）をもち、そのＸ線回折パターンが非晶質の特徴を示し、かつ２５０ｍ２／ｇ以上のＢＥＴ表面積を有する。また、その化学組成は、不純物であるＣｌ，Ｎａ，Ｋ，ＮＯ３，ＳＯ４の総量が質量比で０．２％以下となる。なお、「Ｘ線回折パターンが非晶質の特徴を示す」とは、得られた水酸化ジルコニウムをＸ線回折試験に供したとき、２７〜３３ｄｅｇ．にピークが認められないものをいう。
【００２０】
本発明により製造された水酸化ジルコニウムは、Ｘ線回折パターンが非晶質の特徴を示すので、触媒原料として利用し易いものである。また、不純物量が極めて少ないので、仮焼したとき準安定相である正方晶が発生しがたく、安定な斜方晶が９５％以上の収率で得られるようになり、電子材料として用いたとき導電率、誘電率が安定する。さらに２５０ｍ２／ｇ以上のＢＥＴ表面積を有するので、触媒として用いたとき、接触表面積を増大させることができる。
【００２１】
上記の高比表面積を有する高純度水酸化ジルコニウムは、４００〜１２００℃で仮焼することによって酸化ジルコニウムとすることができる。生成された酸化ジルコニウムは、水酸化ジルコニウムの有する特徴を受け継ぎ、熟成されていないものを基準としたときに比べ、比表面積が３３％以上大きくなる。
【００２２】
これら水酸化ジルコニウム及びそれを仮焼して得られた酸化ジルコニウムは、加圧成形して種々の成形製品とすることができ、特に触媒又は触媒担体としたとき、すぐれた特性を発揮する。
【００２３】
これら水酸化ジルコニウム及びそれを仮焼して得られた酸化ジルコニウムは、成形するに際し、たとえば、酸化イットリウムなどの他の酸化物を混ずることができ、その場合でも配合量が５０％以上あれば、上記特性に由来する特性が発揮される。
【００２４】
【実施例】
（実施例１）
ジルコニア換算５０ｇ／ｌのオキシ塩化ジルコニウム水溶液１ｌをアンモニアでｐＨ ８になるまで中和して水酸化ジルコニウムを生成させた。得られた水酸化ジルコニウムの沈殿をヌツチェでろ過した後、純水で５回繰り返し洗浄を行った。得られたケークに純水を加えて洗浄した後ヌッチェろ過する操作を５回繰り返した。水洗された水酸化ジルコニウムケークに純水を加えて熟成した。熟成条件は表１に示すとおりである。熟成終了後ヌッチェでろ過し、得られたケークを棚式電気乾燥機によって１２０℃にて１昼夜乾燥して水酸化ジルコニウム製品とし純度と比表面積を測定した。測定結果は表１に併せて示す。
【００２５】
（実施例２）
ジルコニア換算８０ｇ／ｌのオキシ塩化ジルコニウム水溶液１ｌを準備し、これにアンモニアを加えｐＨ ８になるまで中和して水酸化ジルコニウムを生成させた。得られた水酸化ジルコニウムの沈殿を、熟成条件を表１に示すものとするほかは実施例１と同様の条件として処理し、得られた製品の純度と比表面積を測定した。測定結果は表１に併せて示す。
【００２６】
（実施例３）
ジルコニア換算５０ｇ／ｌのオキシ塩化ジルコニウム水溶液６００ｌを７０℃に加熱し、硫酸アンモニウム１５ｋｇを加え塩基性硫酸アンモニウム沈殿を生成させた後、アンモニアでｐＨ ８になるまで中和して水酸化ジルコニウムを生成させた。得られた沈殿をフィルタープレスでろ過し、得られたケークに純水を加えて洗浄した後フィルタープレスでろ過する操作を５回繰り返した。得られた水酸化ジルコニウムケークを表１の条件で熟成した。熟成終了後、スラリーをスプレードライヤで乾燥し製品とし、純度と比表面積を測定した。
【００２７】
（比較例１）
ジルコニア換算５０ｇ／ｌのオキシ塩化ジルコニウム溶液１ｌをアンモニアでｐＨ ８になるまで中和して水酸化ジルコニウムを生成させた。得られた水酸化ジルコニウムスラリーを母液とともに濃度２０％になるようにデカンテーションした後に表１の条件で熟成した。熟成終了後、純水で５回繰り返し洗浄を行い得られたケークを棚式電気乾燥機１２０℃にて１昼夜乾燥して製品とし、純度と比表面積を測定した。
【００２８】
（比較例２）
ジルコニア換算５０ｇ／ｌのオキシ塩化ジルコニウム溶液６００ｌを７０℃に加熱し、硫酸アンモニウム１５ｋｇを加え塩基性硫酸アンモニウム沈殿を生成させた後、アンモニアでｐＨ ８になるまで中和して水酸化ジルコニウムを生成させた。得られた水酸化ジルコニウムを含むスラリーを濃度５０％になるように調整した後に表１の条件で熟成した。熟成終了後、得られた沈殿をフィルタープレスでろ過した後、純水で５回繰り返し洗浄を行い水酸化ジルコニウムを得た。得られたスラリーをスプレードライヤで乾燥して製品とし化学純度と比表面積を測定した。
【００２９】
【表１】
【発明の効果】
本発明により、Ｘ線回折パターンが非晶質の特徴を示し、かつ２５０ｍ２／ｇ以上のＢＥＴ表面積を有する高純度水酸化ジルコニウムを経済的に製造することができ、得られた高純度水酸化ジルコニウムを処理して高比表面積を有する酸化ジルコニウムを製造すること、さらに成形製品、特に触媒や触媒担体を製造することを可能になる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to zirconium hydroxide and zirconium oxide having a high specific surface area, a method for producing the same, and a molded product. In particular, the present invention relates to zirconium hydroxide having an amorphous X-ray diffraction pattern, a method for producing the same, zirconium oxide produced based on the same, and a molded product. In addition, in this specification, "zirconium hydroxide" is a general term for what is called zirconium hydroxide and hydrated zirconia.
[0002]
[Prior art]
Zirconium oxide has high heat resistance and a unique crystal structure, and its demand has recently been increasing as a material for highly functional products such as solid electrolytes, petroleum refining catalysts, automobile exhaust gas catalysts, and electronic components. Particularly, those used in the field of catalysts are required to have a large specific surface area in order to increase the contact area.
[0003]
Such zirconium oxide is produced by washing, dehydrating, and calcining zirconium hydroxide generated from an aqueous solution of a zirconium salt by a neutralization method, a hydrolysis method, or the like. As means for increasing the specific surface area, Patent Document 1 discloses a method of drying and calcining a precipitate product obtained by mixing an aqueous solution of zirconium salt with ammonia. A method for producing monoclinic zirconium dioxide having a large specific surface area, wherein the precipitate is aged at 0 to 300 ° C and calcined at 200 to 600 ° C.
[0004]
Non-Patent Document 1 is a paper entitled about the formation of a precipitate of high specific surface area zirconia-the effect of a precipitant and aging, which includes a high specific surface area zirconia by aging a hydroxide at 100 ° C. It has been pointed out that when producing, when aging is carried out with ions brought in from a precursor for forming a precipitate, a neutralizing solution or the like, ions are likely to be incorporated into the lattice and a high-purity product cannot be produced.
[0005]
[Patent Document 1]
JP-A-10-330116 [Non-Patent Document 1]
CHUAH GK, Applied Catalysis A General Vol. 163 (1997) p. 261-273
[0006]
[Problems to be solved by the invention]
However, according to the means described in Patent Document 1, in order to obtain pure monoclinic zirconia according to Example 1, aging must be performed for 432 hours at an aging temperature of 90 ° C. It is shown. On the other hand, Example 3 shows that if the aging temperature is 135 ° C., the aging time can be reduced to 24 hours. According to these embodiments, the means described in Patent Document 1 requires a huge amount of time for maturation, or requires a pressure vessel which is expensive and difficult to process in large quantities if the time is to be shortened. There is. Further, as described in Non-Patent Document 1, there is a problem that it is difficult to produce a high-purity product.
[0007]
An object of the present invention is to solve the problems of the prior art by producing inexpensively zirconium hydroxide, which is a starting material for zirconium dioxide having a high specific surface area, on an industrial scale, and with extremely high purity. To have a high specific surface area, to produce zirconium oxide having a high specific surface area using such zirconium hydroxide as a starting material, and further to produce a molded product, particularly a catalyst or a catalyst carrier, using such zirconium oxide. It provides a means.
[0008]
[Means for Solving the Problems]
The present inventor has found that, by washing zirconium hydroxide or hydrous zirconia to reduce the amount of contaminating ions and aging in that state, amorphous zirconium hydroxide having a high specific surface area can be obtained. Based on the above, the present invention has been completed.
[0009]
The zirconium hydroxide of the present invention has an amorphous X-ray diffraction pattern and a BET surface area of 250 m 2 / g or more.
[0010]
Such zirconium hydroxide was washed in the steps of obtaining zirconium hydroxide or hydrous zirconia, washing the obtained zirconium hydroxide with water to reduce the total content of contaminant ions to 3 mol% or less based on zirconium ions, and The step of ripening zirconium hydroxide can be performed sequentially. At this time, it is desirable that the aging is performed at a temperature of 50 ° C. or higher for 2 to 48 hours.
[0011]
The zirconium hydroxide obtained as described above can be calcined at 400 to 1200 ° C. to obtain zirconium oxide having a high specific surface area. The characteristic is that the monoclinic crystal is 95% or more and the specific surface area is 3 to 150 m. 2 / g. Here, the monoclinic fraction ν m is
[0012]
The above-mentioned zirconium hydroxide or zirconium oxide can be pressure-molded and used as a molded product, and particularly suitably used as a catalyst or a catalyst carrier. It is preferable that these molded products contain zirconium oxide and zirconium oxide in a mass ratio of 50% or more.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the method for producing amorphous zirconium hydroxide having a high specific surface area according to the present invention will be specifically described, and the characteristics and uses of the obtained zirconium hydroxide will also be described.
[0014]
The starting material for producing the amorphous zirconium hydroxide having a high specific surface area according to the present invention is zirconium hydroxide (hydrous zirconia) produced by a known wet method. Examples of such zirconium hydroxide (hydrated zirconia) include: (1) After dissolving a zirconium salt soluble in water or an acid, such as zirconium oxychloride, zirconium nitrate, zirconium sulfate, or zirconium carbonate, which is usually commercially available; Neutralized and precipitated with an alkali such as aqueous ammonia, aqueous sodium hydroxide and aqueous potassium hydroxide; (2) neutralized and precipitated once through an intermediate such as basic zirconium sulfate; or (3) oxy A hydrolyzed zirconium chloride, zirconium nitrate, zirconium sulfate or the like and then neutralized with an alkali such as aqueous ammonia, aqueous sodium hydroxide or aqueous potassium hydroxide can be used.
[0015]
In the present invention, zirconium hydroxide produced by such a known means is first washed with water to make the total content of contaminant ions 3 mol% or less based on zirconium ions. This water washing is performed by adding clear water for washing to the above-mentioned zirconium hydroxide and washing away contaminating ions together with the washing water using a known device such as a filter press, a centrifuge, and a decanter. In this cleaning, a method such as countercurrent multi-stage cleaning can be used, whereby effective use of water can be achieved.
[0016]
Washing is repeated until the total content of impurity ions becomes 3 mol% or less, preferably 1 mol% or less based on zirconium ions. If the washing is not sufficiently performed until the purity reaches a predetermined level, the time required for ripening in the next ripening step becomes longer. Further, zirconium is replaced by impurity ions during aging, and it becomes difficult to obtain high-purity zirconium hydroxide.
[0017]
Next, the zirconium hydroxide whose ionic content has been sufficiently reduced in this way is aged. This aging is carried out by heating the washed zirconium hydroxide to a temperature of 50 ° C. or more, preferably 70 ° C. or more, and keeping it for 2 to 48 hours. Generally, fresh water (electric conductivity: 500 μS / cm or less or a total dissolved substance (TDS) ≦ 300 ppm) is added to the zirconium hydroxide to form a slurry containing 5% or more of zirconium hydroxide by mass ratio, This is performed by heating to the above-mentioned temperature using an appropriate heater such as an electric heater or steam, but the purpose can also be achieved by directly heating the dehydrated cake-like zirconium hydroxide. When the heating temperature is low or the holding time is short, aging does not proceed sufficiently, and it becomes impossible to obtain zirconium hydroxide having a high specific surface area.
[0018]
The aged zirconium hydroxide is dehydrated when the aging is performed in a slurry state, and immediately dried to obtain a product when the aging is performed in a cake state. For drying, a conventional dryer such as a shelf dryer or a spray dryer can be used, but when the drying temperature exceeds 400 ° C., zirconium hydroxide (Zr (OH) 4 ) is dehydrated to zirconia (ZrO 2 ). The drying temperature is set to 400 ° C. or less for crystallization.
[0019]
The zirconium hydroxide thus obtained has a chemical formula (Zr (OH) 4 ), its X-ray diffraction pattern shows amorphous characteristics, and has a BET surface area of 250 m 2 / g or more. Further, the chemical composition thereof is such that the total amount of impurities Cl, Na, K, NO 3 and SO 4 is 0.2% or less by mass ratio. In addition, "X-ray diffraction pattern shows the characteristic of amorphous" means that when the obtained zirconium hydroxide is subjected to an X-ray diffraction test, 27 to 33 deg. No peak is observed.
[0020]
The zirconium hydroxide produced by the present invention is easy to use as a catalyst raw material because the X-ray diffraction pattern shows an amorphous characteristic. Further, since the amount of impurities is extremely small, it is difficult to generate a tetragonal crystal which is a metastable phase when calcined, so that a stable orthorhombic crystal can be obtained at a yield of 95% or more, and it is used as an electronic material. When the conductivity and the permittivity are stabilized. Furthermore, since it has a BET surface area of 250 m 2 / g or more, when used as a catalyst, the contact surface area can be increased.
[0021]
The high-purity zirconium hydroxide having the above high specific surface area can be converted to zirconium oxide by calcining at 400 to 1200 ° C. The generated zirconium oxide inherits the characteristics of zirconium hydroxide, and has a specific surface area of 33% or more as compared with a non-aged zirconium hydroxide.
[0022]
The zirconium hydroxide and the zirconium oxide obtained by calcining the zirconium hydroxide can be formed into various molded products by pressure molding, and exhibit excellent characteristics particularly when used as a catalyst or a catalyst carrier.
[0023]
These zirconium hydroxide and zirconium oxide obtained by calcining the zirconium hydroxide can be mixed with other oxides such as yttrium oxide at the time of molding. The properties derived from the above properties are exhibited.
[0024]
【Example】
(Example 1)
One liter of a 50 g / l zirconia-equivalent aqueous solution of zirconium oxychloride was neutralized with ammonia until pH 8 to form zirconium hydroxide. After the obtained precipitate of zirconium hydroxide was filtered with a nutsche, it was repeatedly washed five times with pure water. The operation of adding pure water to the obtained cake, washing the cake and then performing Nutsche filtration was repeated 5 times. Pure water was added to the washed zirconium hydroxide cake to ripen it. The aging conditions are as shown in Table 1. After completion of the ripening, the cake was filtered through a nutsche, and the obtained cake was dried at 120 ° C. for one day and night using a shelf-type electric drier to obtain a zirconium hydroxide product, and the purity and specific surface area were measured. The measurement results are shown in Table 1.
[0025]
(Example 2)
One liter of an aqueous solution of zirconium oxychloride of 80 g / l in terms of zirconia was prepared, and ammonia was added thereto to neutralize the solution to pH 8 to produce zirconium hydroxide. The obtained precipitate of zirconium hydroxide was treated under the same conditions as in Example 1 except that the aging conditions were as shown in Table 1, and the purity and specific surface area of the obtained product were measured. The measurement results are shown in Table 1.
[0026]
(Example 3)
600 g of a 50 g / l zirconium oxychloride aqueous solution in terms of zirconia was heated to 70 ° C., 15 kg of ammonium sulfate was added to form a basic ammonium sulfate precipitate, and then neutralized to pH 8 with ammonia to form zirconium hydroxide. . The obtained precipitate was filtered with a filter press, the operation of adding pure water to the obtained cake, washing, and then filtering with a filter press was repeated 5 times. The obtained zirconium hydroxide cake was aged under the conditions shown in Table 1. After aging, the slurry was dried with a spray dryer to obtain a product, and the purity and specific surface area were measured.
[0027]
(Comparative Example 1)
One liter of a 50 g / l zirconia-equivalent zirconium oxychloride solution was neutralized with ammonia to pH 8 to produce zirconium hydroxide. The obtained zirconium hydroxide slurry was decanted together with the mother liquor to a concentration of 20%, and then aged under the conditions shown in Table 1. After aging, the cake was repeatedly washed five times with pure water, and the obtained cake was dried at 120 ° C. for one day and night to obtain a product, and its purity and specific surface area were measured.
[0028]
(Comparative Example 2)
600 g of a 50 g / l zirconium oxychloride solution in terms of zirconia was heated to 70 ° C., 15 kg of ammonium sulfate was added to form a basic ammonium sulfate precipitate, and then neutralized to pH 8 with ammonia to form zirconium hydroxide. . The resulting slurry containing zirconium hydroxide was adjusted to a concentration of 50% and then aged under the conditions shown in Table 1. After aging, the obtained precipitate was filtered with a filter press, and washed repeatedly with pure water five times to obtain zirconium hydroxide. The obtained slurry was dried with a spray dryer to obtain a product, and its chemical purity and specific surface area were measured.
[0029]
[Table 1]
【The invention's effect】
According to the present invention, high-purity zirconium hydroxide having an amorphous X-ray diffraction pattern and a BET surface area of 250 m 2 / g or more can be economically produced. It becomes possible to treat zirconium to produce zirconium oxide having a high specific surface area, and to produce molded products, particularly catalysts and catalyst carriers.
Claims (8)
得られた水酸化ジルコニウムを水洗して夾雑イオンの合計含有量をジルコニウムイオンに対し３ｍｏｌ％以下とする段階、
前記段階で水洗された水酸化ジルコニウムを熟成する段階、
を順次行うことを特徴とする請求項１記載の水酸化ジルコニウムの製造方法。Obtaining zirconium hydroxide or hydrous zirconia;
Washing the obtained zirconium hydroxide with water to reduce the total content of impurity ions to 3 mol% or less based on zirconium ions;
Aging the zirconium hydroxide washed with water in the above step,
2. The method for producing zirconium hydroxide according to claim 1, wherein the steps are sequentially performed.
ここで単斜晶率νｍは
Where the monoclinic fraction ν m is
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009525250A (en) * | 2006-02-03 | 2009-07-09 | マグネシウム エレクトロン リミテッド | Zirconium hydroxide |
| WO2014196100A1 (en) * | 2013-06-04 | 2014-12-11 | 新日本電工株式会社 | Ceria-zirconia mixed oxide and method for producing same |
| JP2017039633A (en) * | 2015-08-21 | 2017-02-23 | 国立研究開発法人産業技術総合研究所 | Zirconium hydroxide mesoporous body having carbon dioxide adsorptivity, manufacturing method therefor and carbon dioxide adsorbent consisting of zirconium hydroxide mesoporous body |
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2003
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009525250A (en) * | 2006-02-03 | 2009-07-09 | マグネシウム エレクトロン リミテッド | Zirconium hydroxide |
| WO2014196100A1 (en) * | 2013-06-04 | 2014-12-11 | 新日本電工株式会社 | Ceria-zirconia mixed oxide and method for producing same |
| JP5706546B1 (en) * | 2013-06-04 | 2015-04-22 | 新日本電工株式会社 | Ceria-zirconia composite oxide and method for producing the same |
| US10010868B2 (en) | 2013-06-04 | 2018-07-03 | Nippon Denko Co., Ltd. | Ceria-zirconia-based composite oxide and method of production of the same |
| JP2017039633A (en) * | 2015-08-21 | 2017-02-23 | 国立研究開発法人産業技術総合研究所 | Zirconium hydroxide mesoporous body having carbon dioxide adsorptivity, manufacturing method therefor and carbon dioxide adsorbent consisting of zirconium hydroxide mesoporous body |
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