JP2005200235A - Production method for niobium oxide sol - Google Patents

Production method for niobium oxide sol Download PDF

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JP2005200235A
JP2005200235A JP2004005577A JP2004005577A JP2005200235A JP 2005200235 A JP2005200235 A JP 2005200235A JP 2004005577 A JP2004005577 A JP 2004005577A JP 2004005577 A JP2004005577 A JP 2004005577A JP 2005200235 A JP2005200235 A JP 2005200235A
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niobium oxide
sol
oxalic acid
citric acid
oxide sol
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JP4651000B2 (en
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Isamu Yamaguchi
勇 山口
Hidekazu Ueda
英和 上田
Hiroyuki Izutsu
裕之 井筒
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Taki Chemical Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To produce efficiently a niobium oxide sol which is composed of stable, high-concentration colloid particles and is very useful as a raw material for a catalyst, an optoelectronic material, a semiconductor material, a coating, and the like. <P>SOLUTION: The niobium oxide sol is produced by a method comprising adding citric acid to a niobium oxide sol stabilized with oxalic acid, then adding an aqueous ammonia solution to adjust the pH to 7-10, and removing the oxalic acid. The method can easily produce a niobium oxide sol which exhibits good stability even when colloid particles forming the sol are originally unstable, e.g. when mixed with other ingredients at a high concentration or when the pH fluctuates remarkably. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は酸化ニオブゾルの製造方法に関し、特に高濃度で安定なコロイド粒子からなる酸化ニオブゾルを効率的に製造する方法に関する。
また、本発明で得られる酸化ニオブゾルは、例えば、触媒、オプトエレクトロニクス材料、半導体材料、塗料等の原料として極めて有用である。
The present invention relates to a method for producing a niobium oxide sol, and more particularly to a method for efficiently producing a niobium oxide sol comprising colloidal particles that are stable at a high concentration.
In addition, the niobium oxide sol obtained in the present invention is extremely useful as a raw material for, for example, a catalyst, an optoelectronic material, a semiconductor material, and a paint.

近年、触媒、オプトエレクトロニクス材料、半導体材料、塗料等の材料として酸化ニオブを使用する需要が高まっており、粒子径が小さく、均一な粒度分布を有する酸化ニオブ原料が要求されている。
しかし、酸化ニオブ原料は一般に水酸化ニオブ、酸化ニオブ等の原料粉末を焼成し、これを粉砕して使用されるため、その粒子は不均一であるだけでなく、比較的粒子径の大きな酸化ニオブ原料が使用されている。
In recent years, there is an increasing demand for using niobium oxide as a material for catalysts, optoelectronic materials, semiconductor materials, paints, and the like, and niobium oxide raw materials having a small particle size and a uniform particle size distribution are required.
However, niobium oxide raw materials are generally used by calcining raw material powders such as niobium hydroxide and niobium oxide and pulverizing them, so that the particles are not only non-uniform, but also have a relatively large particle size. Raw materials are used.

このような現状において、粒子径が小さく、また均一な粒度分布を有する酸化ニオブ原料が要求され、これに応じるべく微細粒子の酸化ニオブゾルを提供する技術が開発されている。例えば、本願出願人は、各種目的用途に使用できるしゅう酸安定化酸化ニオブゾルに関する技術を開発し、先に出願を行った。(特許文献1参照)
しかし、この特許文献1の技術によって得られる酸化ニオブゾルは、ゾルの安定性が未だ充分でなく、経時と共に沈殿を生成したり、あるいはゾルが増粘するという問題があった。
そこで、このしゅう酸安定化酸化ニオブゾルについて更に改良を重ねた結果、このゾルにクエン酸を添加し、しゅう酸とクエン酸によってゾルを安定化する方法がゾルの安定性を改善できることを見出し、先に出願を行った。(特許文献2及び3参照)
しかし、これら特許文献2及び3の技術によって得られる酸化ニオブゾルは、安定性が大幅に改善され優れた特性を有するものであったが、濃度が高い場合やpHが著しく変動する場合などでは、安定性が不足し使用用途が制限される場合があった。
Under such circumstances, a niobium oxide raw material having a small particle size and a uniform particle size distribution is required, and a technology for providing a niobium oxide sol having fine particles has been developed to meet this demand. For example, the applicant of the present application developed a technology related to an oxalic acid stabilized niobium oxide sol that can be used for various purposes, and filed an application first. (See Patent Document 1)
However, the niobium oxide sol obtained by the technique of Patent Document 1 still has a problem that the sol is not sufficiently stable and precipitates are formed over time or the sol is thickened.
Therefore, as a result of further improvements to the oxalic acid stabilized niobium oxide sol, it was found that the method of adding citric acid to the sol and stabilizing the sol with oxalic acid and citric acid can improve the stability of the sol. Filed an application. (See Patent Documents 2 and 3)
However, the niobium oxide sols obtained by the techniques of Patent Documents 2 and 3 have significantly improved stability and excellent characteristics. However, when the concentration is high or the pH fluctuates significantly, the niobium oxide sol is stable. In some cases, the usage was limited due to lack of performance.

従って、より安定な酸化ニオブゾルを容易に得ることができれば、前記のごとく利用困難な用途においても使用可能となり、工業的に価値の高いものとなる。このような背景から、更なる酸化ニオブゾルの安定性の向上が強く望まれていた。   Therefore, if a more stable niobium oxide sol can be obtained easily, it can be used in applications that are difficult to use as described above, and it is industrially valuable. Against this background, further improvement in the stability of niobium oxide sol has been strongly desired.

特開平6−321543号公報JP-A-6-321543 特開平8−143314号公報JP-A-8-143314 特開平8−325018号公報JP-A-8-325018

本発明者らは高濃度で安定なコロイド粒子からなる酸化ニオブゾルについて鋭意検討を重ねた結果、酸化ニオブゾルの製造過程に於いて、しゅう酸で安定化した酸化ニオブゾルにクエン酸を加えた後、pHを調整し、次いでしゅう酸を除去することにより、特にゾルの安定性が極めて向上することを見出した。
即ち、本願出願人が既に開示した特許文献2及び3の技術は、しゅう酸安定化酸化ニオブゾルにクエン酸を添加するものであるが、このような製法に於いて、水酸化ニオブの解膠とゾルの安定化のために使用するしゅう酸をクエン酸の添加後に除去することにより、酸化ニオブ粒子がクエン酸でより安定化されるようになり、酸化ニオブゾルの安定性が極めて向上するという知見を得た。
As a result of intensive studies on niobium oxide sol composed of stable colloidal particles at a high concentration, the present inventors added citric acid to niobium oxide sol stabilized with oxalic acid in the manufacturing process of niobium oxide sol, and then adjusted to pH. It was found that the stability of the sol was particularly improved by adjusting the amount and then removing the oxalic acid.
That is, the techniques of Patent Documents 2 and 3 already disclosed by the applicant of the present application are those in which citric acid is added to an oxalic acid-stabilized niobium oxide sol. By removing oxalic acid used to stabilize the sol after the addition of citric acid, the niobium oxide particles become more stabilized with citric acid, and the knowledge that the stability of the niobium oxide sol is greatly improved. Obtained.

更に、高濃度の酸化ニオブゾルを得る方法として、上記のような手段によって得られる酸化ニオブゾルに、酸性化合物を添加し酸性ゾルとすることによって高濃度でしかも更に安定性の優れた酸化ニオブゾルを得ることが可能となることを見出し、係る知見に基づき本発明を完成したものである。   Furthermore, as a method for obtaining a high concentration niobium oxide sol, a niobium oxide sol having a high concentration and further excellent stability can be obtained by adding an acidic compound to the niobium oxide sol obtained by the above means to obtain an acidic sol. The present invention has been completed based on such findings.

即ち本発明は、しゅう酸安定化酸化ニオブゾルにクエン酸を加えた後、アンモニア水溶液を添加してpHを7〜10に調整し、次いでしゅう酸を除去することを特徴とする酸化ニオブゾルの製造方法に関する。   That is, the present invention provides a method for producing a niobium oxide sol characterized by adding citric acid to an oxalic acid-stabilized niobium oxide sol, adding an aqueous ammonia solution to adjust the pH to 7 to 10, and then removing the oxalic acid. About.

また本発明は、しゅう酸安定化酸化ニオブゾルにクエン酸を加えた後、アンモニア水溶液を添加してpHを7〜10に調整し、次いでしゅう酸を除去した後、これに酸性化合物を添加することを特徴とする酸化ニオブゾルの製造方法に関する。   In the present invention, citric acid is added to an oxalic acid-stabilized niobium oxide sol, then an aqueous ammonia solution is added to adjust the pH to 7 to 10, and after removing oxalic acid, an acidic compound is added thereto. The present invention relates to a method for producing a niobium oxide sol.

この様な製法によって得られる酸化ニオブゾルは、クエン酸/しゅう酸(モル比)0.5以上で、且つしゅう酸/酸化ニオブ(モル比)0.5以下である酸化ニオブゾルとして得ることができる。
しゅう酸を除去するために、しゅう酸安定化酸化ニオブゾルの製造時の水酸化ニオブの解膠時に予めしゅう酸添加量を少なくしておくことが考えられる。しかし、しゅう酸/酸化ニオブ(モル比)が0.5を下廻る条件では解膠が不充分となり、反応時間が著しく長くなるために、得られるゾルの粒度分布が広くなりヘーズ率が高くなるなどの問題が生じる。従って、上記の解膠時には所定量のしゅう酸は必須である。
The niobium oxide sol obtained by such a production method can be obtained as a niobium oxide sol having a citric acid / oxalic acid (molar ratio) of 0.5 or more and an oxalic acid / niobium oxide (molar ratio) of 0.5 or less.
In order to remove oxalic acid, it is conceivable to reduce the amount of oxalic acid added in advance during the peptization of niobium hydroxide during the production of the oxalic acid stabilized niobium oxide sol. However, under conditions where the oxalic acid / niobium oxide (molar ratio) is less than 0.5, peptization becomes insufficient and the reaction time becomes extremely long, so that the particle size distribution of the resulting sol is widened and the haze ratio is increased. Problems arise. Therefore, a predetermined amount of oxalic acid is essential at the time of peptization.

また、別の手段として、しゅう酸安定化酸化ニオブゾルを限外濾過装置等を用いてしゅう酸/酸化ニオブ(モル比)が0.5を下廻るようになるまで洗浄するという手段が考えられる。しかし、しゅう酸/酸化ニオブのモル比が小さくなると、しゅう酸が酸化ニオブ粒子に強固に結着しているため、しゅう酸の洗浄除去効率が著しく低下するだけでなく、得られるゾルは、ゾルの安定化に寄与していたしゅう酸が不足し、増粘やゲル化を生じ不安定なゾルとなる。
従って、しゅう酸安定化ゾルは、しゅう酸に代えてクエン酸を使用することは出来ず、しゅう酸安定化ゾルにクエン酸を加えておくことは必須の条件である。
As another means, it is conceivable to wash the oxalic acid stabilized niobium oxide sol using an ultrafiltration device or the like until the oxalic acid / niobium oxide (molar ratio) falls below 0.5. However, when the molar ratio of oxalic acid / niobium oxide is reduced, oxalic acid is strongly bound to the niobium oxide particles, so that not only the cleaning removal efficiency of oxalic acid is remarkably lowered, but the resulting sol is a sol This contributes to the stabilization of oxalic acid, resulting in insufficient oxalic acid, resulting in thickening and gelation, resulting in an unstable sol.
Therefore, citric acid cannot be used in the oxalic acid stabilized sol in place of oxalic acid, and it is an essential condition to add citric acid to the oxalic acid stabilized sol.

本発明の酸化ニオブゾル製造方法は、他成分と高濃度で混合する場合、pHが著しく変動する場合など、元来ゾルを形成するコロイド粒子が不安定となる場面でも良好な安定性を示すゾルを容易に製造することができる。
また、本発明の方法により広範な原料用途に適応できるゾルを提供することができ、これによって得られるゾルは、例えば、触媒、オプトエレクトロニクス材料、半導体材料、塗料、表面保護剤等の原料として極めて有用である。
The niobium oxide sol production method of the present invention is a sol that exhibits good stability even when the colloidal particles that originally form the sol become unstable, such as when mixed with other components at a high concentration or when the pH fluctuates significantly. It can be manufactured easily.
Further, the method of the present invention can provide a sol that can be applied to a wide range of raw material applications, and the sol obtained thereby can be used as a raw material for, for example, a catalyst, an optoelectronic material, a semiconductor material, a paint, a surface protective agent, and the like. Useful.

本発明の酸化ニオブゾルの製造方法は、しゅう酸安定化酸化ニオブゾルにクエン酸を加えた後、アンモニア水溶液を添加してpHを7〜10に調整し、次いでしゅう酸を除去するという方法である。   The niobium oxide sol production method of the present invention is a method in which citric acid is added to an oxalic acid-stabilized niobium oxide sol, an aqueous ammonia solution is added to adjust the pH to 7 to 10, and then oxalic acid is removed.

この製造方法に関して詳記すれば、公知の方法例えば、特許文献1に記載する方法によって得られるしゅう酸安定化酸化ニオブゾルを使用原料とする。
今、そのしゅう酸安定化酸化ニオブゾルの製造方法を例示すると、先ず酸化ニオブをフッ化水素酸に溶解し、この溶液をアンモニア水に添加した後、フィルタープレスでろ過、洗浄を行い活性な水酸化ニオブのスラリーを得る。このスラリーにしゅう酸/Nb2O5(モル比)=0.9〜2.5の範囲となるようにしゅう酸を添加し、温度90℃以上で4時間以上の加熱反応を行いしゅう酸安定化酸化ニオブゾルを得ることができる。なお、しゅう酸安定化酸化ニオブゾルのしゅう酸量は、限外洗浄装置などを用いて、しゅう酸/酸化ニオブモル比が0.7〜1.0の範囲となるようにする。
If this manufacturing method is described in detail, the oxalic acid stabilized niobium oxide sol obtained by a known method such as the method described in Patent Document 1 is used as a raw material.
An example of a method for producing the oxalic acid-stabilized niobium oxide sol is as follows. First, niobium oxide is dissolved in hydrofluoric acid, and this solution is added to aqueous ammonia. A slurry of niobium is obtained. Oxalic acid is added to this slurry so that oxalic acid / Nb 2 O 5 (molar ratio) is in the range of 0.9 to 2.5, and the reaction is performed at a temperature of 90 ° C. or more for 4 hours or more to stabilize oxalic acid. A niobium oxide sol can be obtained. The amount of oxalic acid in the oxalic acid-stabilized niobium oxide sol is adjusted so that the oxalic acid / niobium oxide molar ratio is in the range of 0.7 to 1.0 using an ultra-cleaning device or the like.

本発明の酸化ニオブゾルの製造方法は、上記のようにして得られるしゅう酸安定化酸化ニオブゾルに、クエン酸を添加した後、アンモニア水溶液を添加してpHを7〜10に調整する。
クエン酸は、粉末状態で添加しても、水溶液で添加しても良く、これによって得られる酸化ニオブゾルの性能に影響を与えることはない。また、クエン酸以外でも添加後にクエン酸イオンを供給するクエン酸塩類を使用することができ、このような塩類としては、クエン酸アンモニウム、クエン酸ナトリウム、クエン酸カリウムなどを例示できる。
In the method for producing a niobium oxide sol of the present invention, citric acid is added to the oxalic acid stabilized niobium oxide sol obtained as described above, and then an aqueous ammonia solution is added to adjust the pH to 7-10.
Citric acid may be added in a powder state or in an aqueous solution, and this does not affect the performance of the niobium oxide sol obtained. In addition to citrate, citrates that supply citrate ions after addition can be used, and examples of such salts include ammonium citrate, sodium citrate, and potassium citrate.

クエン酸の添加量に関して云えば、特に限定する必要はないが、一度に加えるクエン酸量は、クエン酸/Nb2O5(モル比)=0.1〜0.5の範囲となるようにクエン酸を添加することが好ましい。即ち、クエン酸/Nb2O5(モル比)が0.1を下廻りクエン酸量が不足すると、後述の処理を行ってもクエン酸/しゅう酸(モル比)が0.5以上のゾルを得ることが困難となる。また反対に、クエン酸/Nb2O5(モル比)が0.5を上廻り、過剰のクエン酸を添加しても、安定性に寄与しないクエン酸が増加するだけであり経済的でない。 The amount of citric acid added is not particularly limited, but the amount of citric acid added at a time is in a range of citric acid / Nb 2 O 5 (molar ratio) = 0.1 to 0.5. It is preferred to add citric acid. That is, when the citric acid / Nb 2 O 5 (molar ratio) is less than 0.1 and the amount of citric acid is insufficient, a sol having a citric acid / oxalic acid (molar ratio) of 0.5 or more is obtained even after the treatment described below. It becomes difficult to obtain. Conversely, citric acid / Nb 2 O 5 (molar ratio) exceeds 0.5, and adding excess citric acid only increases citric acid that does not contribute to stability, which is not economical.

次に、クエン酸を添加したしゅう酸安定化酸化ニオブゾルは、これにアンモニア水溶液を添加してpHを7〜10に調整する。このとき添加するアンモニア水溶液の濃度は特に制限されることはなく、10〜30質量%程度のアンモニア水溶液を使用し、溶液を撹拌しながら添加すればよい。
また、アンモニア水溶液によって調整されたpHが7未満の場合では、外観的にはゾル溶液は特に変化はないものの、しゅう酸の除去効率が低下し、しゅう酸/酸化ニオブ(モル比)が0.5以下のゾルを得ることが困難となり好ましくない。また、pHが10以上となると、ゾルの溶解や増粘、ゲル化を生じる場合があり、そのような場合には酸化ニオブゾルの濃度を低濃度にしても、後述する手段でのしゅう酸の除去が困難となり、本発明の酸化ニオブゾルを得ることができない。従って、アンモニア水溶液を添加して行うpHの調整では、pHは7〜10に、更に好ましくは、pH8〜9の範囲に調整することが好ましい。
また、pH調整の際の酸化ニオブ濃度については、特に制限はないが、通常10%以下の濃度で行うことが推奨される。即ち、しゅう酸、クエン酸の含有量や調整するpHによっては、ゾル溶液は粘度が高くなる場合があり、その場合には更に希釈して低濃度で行うことが好ましい。
Next, the oxalic acid-stabilized niobium oxide sol to which citric acid has been added is adjusted to a pH of 7 to 10 by adding an aqueous ammonia solution thereto. The concentration of the aqueous ammonia solution added at this time is not particularly limited, and an aqueous ammonia solution of about 10 to 30% by mass may be used and the solution may be added while stirring.
Further, when the pH adjusted by the aqueous ammonia solution is less than 7, the sol solution is not particularly changed in appearance, but the removal efficiency of oxalic acid is lowered, and the oxalic acid / niobium oxide (molar ratio) is 0. It becomes difficult to obtain a sol of 5 or less, which is not preferable. In addition, when the pH is 10 or more, dissolution, thickening, and gelation of the sol may occur. In such a case, even if the niobium oxide sol concentration is low, removal of oxalic acid by means described later. Thus, the niobium oxide sol of the present invention cannot be obtained. Therefore, in pH adjustment performed by adding an aqueous ammonia solution, it is preferable to adjust the pH to 7 to 10, more preferably to the range of pH 8 to 9.
Further, the niobium oxide concentration at the time of pH adjustment is not particularly limited, but it is recommended that the concentration is usually 10% or less. That is, depending on the content of oxalic acid and citric acid and the pH to be adjusted, the sol solution may have a high viscosity. In this case, it is preferable to dilute the sol solution at a low concentration.

pH調整を行った後の酸化ニオブゾル溶液は、次いで限外濾過装置等を使用し、しゅう酸を除去する。しゅう酸の除去は、アンモニア水溶液の添加によって選択的にしゅう酸アンモニウムとして洗浄、除去され、ゾル溶液中にはクエン酸によって安定化された酸化ニオブゾルが生成する。驚くべきことに、この洗浄においてクエン酸は全く除去されることはない。
また、限外濾過装置による洗浄は、所望のしゅう酸が除去できるまで行なうことができ、例えば、洗浄濾液中のしゅう酸濃度を測定しながら洗浄の終点を決定すればよい。
The niobium oxide sol solution after pH adjustment is followed by removal of oxalic acid using an ultrafiltration device or the like. Removal of oxalic acid is selectively washed and removed as ammonium oxalate by addition of an aqueous ammonia solution, and a niobium oxide sol stabilized with citric acid is generated in the sol solution. Surprisingly, no citric acid is removed in this wash.
Further, the washing with the ultrafiltration device can be performed until the desired oxalic acid can be removed. For example, the end point of washing may be determined while measuring the concentration of oxalic acid in the washing filtrate.

また、洗浄は数回に分けて行うことも可能であり、一回目の洗浄後にクエン酸とアンモニア水溶液を更に添加して洗浄することにより、しゅう酸の除去率が向上し、ゾル溶液の安定性が向上する。
肝心なことは、このような工程によって、しゅう酸/酸化ニオブ(モル比)が0.5以下となるまで洗浄することであり、これによって酸化ニオブゾルの安定性が飛躍的に向上する。
洗浄によってしゅう酸が除去された後には、酸化ニオブの濃度を調整すればよい。このような濃度調整は、限外濾過洗浄中に行うこともできるが、加熱濃縮や減圧蒸留等の手段を用いて行うこともできる。
In addition, washing can be performed in several steps. By adding and washing citric acid and aqueous ammonia after the first washing, the removal rate of oxalic acid is improved and the stability of the sol solution is improved. Will improve.
What is important is to perform washing until the oxalic acid / niobium oxide (molar ratio) is 0.5 or less by such a process, thereby dramatically improving the stability of the niobium oxide sol.
After the oxalic acid is removed by washing, the concentration of niobium oxide may be adjusted. Such concentration adjustment can be performed during ultrafiltration washing, but can also be performed using means such as heat concentration and vacuum distillation.

このようにして得ることができる本発明の酸化ニオブゾルは、ゾル溶液のpHが7.0〜8.0の範囲であるが、前述の様な濃縮手段によって酸化ニオブの濃度は約20%まで濃縮できる。この様な酸化ニオブゾルに酸性化合物を添加することにより、本発明ではゾルのpHが3〜7であって更に高濃度の酸化ニオブゾルを得ることができる。特に本発明のゾルを酸性化合物の添加によってpH3〜5とすることにより、本発明の酸化ニオブゾルは、前述のような濃縮工程を経ることで、酸化ニオブの濃度が約35%まで濃縮を行っても安定なゾル溶液として得ることができ、経時保存後も高い流動性を保ち、沈殿の生成を殆ど生じない安定なゾル溶液となる。
また、この場合に使用できる酸性化合物の種類としては、クエン酸が最も好ましいが、ゾル中のクエン酸/しゅう酸(モル比)が0.5以上であれば、クエン酸以外のリンゴ酸、酒石酸、乳酸などのヒドロキシカルボン酸を酸性化合物として用いることができる。
The niobium oxide sol of the present invention that can be obtained in this manner has a pH of 7.0 to 8.0 in the sol solution. The niobium oxide concentration is concentrated to about 20% by the concentration means as described above. it can. By adding an acidic compound to such a niobium oxide sol, in the present invention, a niobium oxide sol having a higher sol pH of 3 to 7 can be obtained. In particular, the niobium oxide sol of the present invention is concentrated to the concentration of niobium oxide to about 35% through the concentration step as described above by adjusting the sol of the present invention to pH 3 to 5 by adding an acidic compound. Can be obtained as a stable sol solution, maintains a high fluidity even after storage over time, and becomes a stable sol solution that hardly generates precipitates.
In addition, citric acid is most preferable as the kind of acidic compound that can be used in this case. However, if the citric acid / oxalic acid (molar ratio) in the sol is 0.5 or more, malic acid other than citric acid, tartaric acid Hydroxycarboxylic acids such as lactic acid can be used as the acidic compound.

本発明の酸化ニオブゾルは、このような方法により酸化ニオブゾルがクエン酸/しゅう酸(モル比)0.5以上で、且つしゅう酸/酸化ニオブ(モル比)0.5以下である酸化ニオブゾルとして得ることができる。
また本発明の製造方法によって得られた酸化ニオブゾルは、前述のように酸性化合物を添加して酸性のゾルとするだけでなく、反対に塩基化合物を使用してゾル溶液pHが8〜10の範囲のアルカリ安定酸化ニオブゾルとすることもできる。このような塩基化合物としては、アンモニア水溶液だけでなく、メチルアミン、ジエチルアミン、トリメチルアミン、エチレンジアミン、テトラメチルアンモニウム等の1〜4級のアミン類、メタノールアミン、エタノールアミン等の水酸基を有するアルカノールアミン類を例示することができる。
The niobium oxide sol of the present invention is obtained by such a method as a niobium oxide sol having a citric acid / oxalic acid (molar ratio) of 0.5 or more and an oxalic acid / niobium oxide (molar ratio) of 0.5 or less. be able to.
Further, the niobium oxide sol obtained by the production method of the present invention is not only made into an acidic sol by adding an acidic compound as described above, but on the contrary, the sol solution pH is in the range of 8 to 10 using a basic compound. An alkali stable niobium oxide sol can also be used. Examples of such basic compounds include not only aqueous ammonia solutions, but also primary to quaternary amines such as methylamine, diethylamine, trimethylamine, ethylenediamine, and tetramethylammonium, and alkanolamines having hydroxyl groups such as methanolamine and ethanolamine. It can be illustrated.

以下に本発明の実施例を掲げ更に説明を行うが、本発明はこれらに限定されるものではない。また、%は特に断らない限りすべて質量%を示す。   Examples of the present invention will be described below and further explained, but the present invention is not limited to these. Moreover, unless otherwise indicated, all% shows the mass%.

五酸化ニオブ(多木化学(株)製)400gを、弗化水素酸(10%)4.2Lに溶解した。この溶液をアンモニア水溶液(15%)2.8Lに60分間かけて添加した後、フィルタープレスで濾過、洗浄して水酸化ニオブのスラリーを得た。このスラリーを更に限外濾過装置を用いてアンモニア成分を除去した。得られた水酸化ニオブの組成分析を行ったところ、Nb2O5含有量は、25.0%、NH3/Nb2O5(モル比)=1.5であった。
この水酸化ニオブ400gに水600gを加え、Nb2O5含有量を10.0%とした。次いで、これにしゅう酸/Nb2O5(モル比)=1.25となるようにしゅう酸二水和物を添加し、撹拌還流下、95℃で加熱反応を行った。
反応の進行に伴い、溶液は次第に青色を帯び、均一なゾル状態を呈した。この時点をもって、反応を終了した。
このしゅう酸安定化酸化ニオブゾルに1000gの水を加え、限外濾過装置(旭化成工業製,SLP−1053型)を使用して、濾液の電気伝導度が0.5s/m以下になるまで洗浄した。またこの時のゾル濃度は、Nb2O5 10.0%に調整した。
400 g of niobium pentoxide (manufactured by Taki Chemical Co., Ltd.) was dissolved in 4.2 L of hydrofluoric acid (10%). This solution was added to 2.8 L of an aqueous ammonia solution (15%) over 60 minutes, and then filtered and washed with a filter press to obtain a slurry of niobium hydroxide. The ammonia component was further removed from the slurry using an ultrafiltration device. When the composition analysis of the obtained niobium hydroxide was conducted, the Nb 2 O 5 content was 25.0% and NH 3 / Nb 2 O 5 (molar ratio) = 1.5.
600 g of water was added to 400 g of this niobium hydroxide to make the Nb 2 O 5 content 10.0%. Next, oxalic acid dihydrate was added thereto so that oxalic acid / Nb 2 O 5 (molar ratio) = 1.25, and a heating reaction was performed at 95 ° C. with stirring and reflux.
As the reaction progressed, the solution gradually turned blue and exhibited a uniform sol state. At this point, the reaction was complete.
1000 g of water was added to this oxalic acid stabilized niobium oxide sol and washed using an ultrafiltration device (Asahi Kasei Kogyo, SLP-1053 type) until the electrical conductivity of the filtrate was 0.5 s / m or less. . The sol concentration at this time was adjusted to 10.0% Nb 2 O 5 .

この様にして得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸/Nb2O5(モル比)=0.30となるようにクエン酸一水和物を添加した。
更に、このゾルを限外濾過装置を使用して、Nb2O5濃度=20%まで濃縮した。このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.35、クエン酸/Nb2O5(モル比)=0.30であり、クエン酸/しゅう酸(モル比)は0.86であった。
また、得られた酸化ニオブゾルのpHは4.2、粘度は6.2cpであった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol thus obtained so that citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%) Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol is washed using an ultrafiltration device until the electric conductivity of the filtrate is 0.4 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.30. Citric acid monohydrate was added.
Furthermore, this sol was concentrated to Nb 2 O 5 concentration = 20% using an ultrafiltration device. In the niobium oxide sol thus obtained, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.35 and citric acid / Nb 2 O 5 (molar ratio) = 0.30. Yes, the citric acid / oxalic acid (molar ratio) was 0.86.
The obtained niobium oxide sol had a pH of 4.2 and a viscosity of 6.2 cp.

実施例1で使用したしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.3s/m以下になるまで洗浄した後、クエン酸/Nb2O5(モル比)=0.15となるようにクエン酸一水和物を添加した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.15、クエン酸/Nb2O5(モル比)=0.35であり、クエン酸/しゅう酸(モル比)は2.33であった。
更に、このゾルをロータリーエバポレーターを使用し、減圧下、温度70℃で加熱することにより、Nb2O5濃度を30%まで濃縮した。
Citric acid monohydrate was added to the oxalic acid stabilized niobium oxide sol used in Example 1 so that the citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%). Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
The sol is washed using an ultrafiltration device until the electric conductivity of the filtrate becomes 0.3 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.15. Citric acid monohydrate was added.
In the niobium oxide sol thus obtained, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.15 and citric acid / Nb 2 O 5 (molar ratio) = 0.35. Yes, citric acid / oxalic acid (molar ratio) was 2.33.
Furthermore, this sol was heated at a temperature of 70 ° C. under reduced pressure using a rotary evaporator to concentrate the Nb 2 O 5 concentration to 30%.

実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸一水和物とイオン交換水を添加してゾルのpHを4.0、Nb2O5濃度を10%に調整した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.20、クエン酸/Nb2O5(モル比)=0.51であり、クエン酸/しゅう酸(モル比)は2.55であった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that the citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%) Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol was washed using an ultrafiltration device until the electric conductivity of the filtrate was 0.4 s / m or less, and then citric acid monohydrate and ion exchange water were added to adjust the pH of the sol to 4 0.0, Nb 2 O 5 concentration was adjusted to 10%.
In the niobium oxide sol thus obtained, oxalic acid and citric acid had oxalic acid / Nb 2 O 5 (molar ratio) = 0.20 and citric acid / Nb 2 O 5 (molar ratio) = 0.51. The citric acid / oxalic acid (molar ratio) was 2.55.

実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸一水和物とイオン交換水を添加してゾルのpHを7.0、Nb2O5濃度を10%に調整した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.20、クエン酸/Nb2O5(モル比)=0.31であり、クエン酸/しゅう酸(モル比)は1.55であった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that the citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%) Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol was washed using an ultrafiltration device until the electric conductivity of the filtrate was 0.4 s / m or less, and then citric acid monohydrate and ion-exchanged water were added to adjust the pH of the sol to 7 0.0, Nb 2 O 5 concentration was adjusted to 10%.
In the niobium oxide sol thus obtained, oxalic acid and citric acid had oxalic acid / Nb 2 O 5 (molar ratio) = 0.20 and citric acid / Nb 2 O 5 (molar ratio) = 0.31. Yes, citric acid / oxalic acid (molar ratio) was 1.55.

実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸/Nb2O5(モル比)=0.15となるようにクエン酸一水和物を添加した後、テトラメチルアンモニウム水溶液(10%)を用いてゾルのpHを9.0に調整した。また、Nb2O5濃度は、イオン交換水を添加して10%に調整した。
得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.20、クエン酸/Nb2O5(モル比)=0.35であり、クエン酸/しゅう酸(モル比)は1.75であった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that the citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%) Was used to adjust the pH to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol is washed using an ultrafiltration device until the electric conductivity of the filtrate is 0.4 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.15. After adding citric acid monohydrate, the pH of the sol was adjusted to 9.0 using an aqueous tetramethylammonium solution (10%). The Nb 2 O 5 concentration was adjusted to 10% by adding ion exchange water.
In the obtained niobium oxide sol, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.20, citric acid / Nb 2 O 5 (molar ratio) = 0.35, and citric acid / Oxalic acid (molar ratio) was 1.75.

実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.40となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.20、クエン酸/Nb2O5(モル比)=0.40であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、テトラメチルアンモニウム水溶液(10%)を用いてゾルのpHを9.0に調整した。また、Nb2O5濃度は、イオン交換水を添加して10%に調整した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.12、クエン酸/Nb2O5(モル比)=0.33であり、クエン酸/しゅう酸(モル比)は2.75であった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that citric acid / Nb 2 O 5 (molar ratio) = 0.40, and then an aqueous ammonia solution (15%) Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.20 and citric acid / Nb 2 O 5 (molar ratio) = 0.40.
The sol was washed using an ultrafiltration device until the electric conductivity of the filtrate was 0.4 s / m or less, and then the pH of the sol was adjusted to 9.0 using an aqueous tetramethylammonium solution (10%). It was adjusted. The Nb 2 O 5 concentration was adjusted to 10% by adding ion exchange water.
In the niobium oxide sol thus obtained, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.12 and citric acid / Nb 2 O 5 (molar ratio) = 0.33. Yes, citric acid / oxalic acid (molar ratio) was 2.75.

実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸/Nb2O5(モル比)=0.15となるようにクエン酸一水和物を添加し、アンモニア水(15%)を用いてゾルのpHを8.5に調整した。このゾルを限外洗浄装置を使用して、濾液の電気伝導度が0.2s/m以下になるまで洗浄した後、これにクエン酸/Nb2O5(モル比)=0.15となるようにクエン酸一水和物を添加し、最後にテトラメチルアンモニウム水溶液(10%)を用いてゾルのpHを9.0に調整した。また、Nb2O5濃度は、イオン交換水を添加して10%に調整した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.024、クエン酸/Nb2O5(モル比)=0.44であり、クエン酸/しゅう酸(モル比)は18.33であった。
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that the citric acid / Nb 2 O 5 (molar ratio) = 0.20, and then an aqueous ammonia solution (15%) Was used to adjust the pH of the sol to 8.5.
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.70 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol is washed using an ultrafiltration device until the electric conductivity of the filtrate is 0.4 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.15. Citric acid monohydrate was added and the pH of the sol was adjusted to 8.5 using aqueous ammonia (15%). This sol was washed using an ultra-cleaning device until the electric conductivity of the filtrate was 0.2 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.15. Then, citric acid monohydrate was added, and finally the pH of the sol was adjusted to 9.0 using an aqueous tetramethylammonium solution (10%). The Nb 2 O 5 concentration was adjusted to 10% by adding ion exchange water.
In the niobium oxide sol thus obtained, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.024 and citric acid / Nb 2 O 5 (molar ratio) = 0.44. Yes, citric acid / oxalic acid (molar ratio) was 18.33.

市販のしゅう酸安定化酸化ニオブゾル(多木化学(株)製、Nb2O5=10.2%、しゅう酸/Nb2O5(モル比)=0.62)に、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した後、アンモニア水溶液(15%)を用いてゾルのpHを8.5に調整した。
この時の酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.62、クエン酸/Nb2O5(モル比)=0.20であった。
このゾルを限外濾過装置を使用して、濾液の電気伝導度が0.4s/m以下になるまで洗浄した後、クエン酸/Nb2O5(モル比)=0.15となるようにクエン酸一水和物を添加した。次に、テトラメチルアンモニウム水溶液(10%)を用いてゾルのpHを9.0に調整した。また、Nb2O5濃度は、イオン交換水を添加して10%に調整した。
このようにして得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.18、クエン酸/Nb2O5(モル比)=0.35であり、クエン酸/しゅう酸(モル比)は1.75であった。
Commercially available oxalic acid stabilized niobium oxide sol (manufactured by Taki Chemical Co., Ltd., Nb 2 O 5 = 10.2%, oxalic acid / Nb 2 O 5 (molar ratio) = 0.62), citric acid / Nb 2 After adding citric acid monohydrate so that O 5 (molar ratio) = 0.20, the pH of the sol was adjusted to 8.5 using an aqueous ammonia solution (15%).
In this niobium oxide sol, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.62 and citric acid / Nb 2 O 5 (molar ratio) = 0.20.
This sol is washed using an ultrafiltration device until the electric conductivity of the filtrate is 0.4 s / m or less, and then citric acid / Nb 2 O 5 (molar ratio) = 0.15. Citric acid monohydrate was added. Next, the pH of the sol was adjusted to 9.0 using an aqueous tetramethylammonium solution (10%). The Nb 2 O 5 concentration was adjusted to 10% by adding ion exchange water.
In the niobium oxide sol thus obtained, oxalic acid and citric acid were oxalic acid / Nb 2 O 5 (molar ratio) = 0.18 and citric acid / Nb 2 O 5 (molar ratio) = 0.35. Yes, the citric acid / oxalic acid (molar ratio) was 1.75.

[比較例1]
実施例1で得たしゅう酸安定化酸化ニオブゾルに、クエン酸/Nb2O5(モル比)=0.20となるようにクエン酸一水和物を添加した。
得られた酸化ニオブゾルは、しゅう酸とクエン酸が、しゅう酸/Nb2O5(モル比)=0.70、クエン酸/Nb2O5(モル比)=0.20であり、クエン酸/しゅう酸(モル比)は0.29であった。
得られたゾルをロータリーエバポレーターを使用して、Nb2O5濃度=20%まで濃縮したところ、このものは12時間以内にゲル化し流動性を失った。
[Comparative Example 1]
Citric acid monohydrate was added to the oxalic acid-stabilized niobium oxide sol obtained in Example 1 so that citric acid / Nb 2 O 5 (molar ratio) = 0.20.
In the obtained niobium oxide sol, oxalic acid and citric acid are oxalic acid / Nb 2 O 5 (molar ratio) = 0.70, citric acid / Nb 2 O 5 (molar ratio) = 0.20, and citric acid / Oxalic acid (molar ratio) was 0.29.
When the obtained sol was concentrated to Nb 2 O 5 concentration = 20% using a rotary evaporator, it gelled within 12 hours and lost fluidity.

[比較例2]
市販のしゅう酸安定化酸化ニオブゾル(多木化学(株)製、Nb2O5=10.2%、しゅう酸/Nb2O5(モル比)=0.62)を、限外濾過装置を使用して、Nb2O5濃度=20%まで濃縮した。このとき、ゾルは濃縮過程でゲル化し流動性を失った。
[Comparative Example 2]
Commercially available oxalic acid stabilized niobium oxide sol (manufactured by Taki Chemical Co., Ltd., Nb 2 O 5 = 10.2%, oxalic acid / Nb 2 O 5 (molar ratio) = 0.62) Used to concentrate to Nb 2 O 5 concentration = 20%. At this time, the sol gelled during the concentration process and lost its fluidity.

以上実施例1〜8及び比較例1〜2で製造した酸化ニオブゾルの物性をまとめて表1に示した。   The physical properties of the niobium oxide sol produced in Examples 1 to 8 and Comparative Examples 1 and 2 are summarized in Table 1.

Figure 2005200235
Figure 2005200235

実施例1〜8及び比較例1〜2で製造した酸化ニオブゾルを、恒温器中で30℃に保持し、30日間及び3ケ月間静置した後のゾルの状態を観察した。その結果を表2に示した。 The niobium oxide sol produced in Examples 1 to 8 and Comparative Examples 1 and 2 was maintained at 30 ° C. in a thermostatic chamber, and the state of the sol after being allowed to stand for 30 days and 3 months was observed. The results are shown in Table 2.

Figure 2005200235
Figure 2005200235

Claims (3)

しゅう酸安定化酸化ニオブゾルにクエン酸を加えた後、アンモニア水溶液を添加してpHを7〜10に調整し、次いでしゅう酸を除去することを特徴とする酸化ニオブゾルの製造方法。 A method for producing a niobium oxide sol comprising adding citric acid to an oxalic acid-stabilized niobium oxide sol, adding an aqueous ammonia solution to adjust the pH to 7 to 10, and then removing the oxalic acid. しゅう酸安定化酸化ニオブゾルにクエン酸を加えた後、アンモニア水溶液を添加してpHを7〜10に調整し、次いでしゅう酸を除去した後、これに酸性化合物を添加することを特徴とする酸化ニオブゾルの製造方法。 Oxidation characterized by adding citric acid to oxalic acid stabilized niobium oxide sol, adding aqueous ammonia solution to adjust pH to 7-10, then removing oxalic acid and adding acidic compound to it A method for producing niobium sol. 得られた酸化ニオブゾルがクエン酸/しゅう酸(モル比)0.5以上で、且つしゅう酸/酸化ニオブ(モル比)0.5以下である請求項1又は2記載の酸化ニオブゾルの製造方法。
The method for producing a niobium oxide sol according to claim 1 or 2, wherein the obtained niobium oxide sol has a citric acid / oxalic acid (molar ratio) of 0.5 or more and an oxalic acid / niobium oxide (molar ratio) of 0.5 or less.
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Publication number Priority date Publication date Assignee Title
KR20230116777A (en) 2020-12-08 2023-08-04 디아이씨 가부시끼가이샤 Niobium oxide particles and method for producing niobium oxide particles

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JPH06321543A (en) * 1993-05-17 1994-11-22 Taki Chem Co Ltd Niobium pentaoxide sol and its production
JPH08143314A (en) * 1994-11-18 1996-06-04 Taki Chem Co Ltd Stabilized niobium oxide sol and its production
JPH08277115A (en) * 1996-05-20 1996-10-22 Nissan Chem Ind Ltd Zirconia sol
JPH08325018A (en) * 1995-05-30 1996-12-10 Taki Chem Co Ltd Niobium oxide sol

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JPH03153527A (en) * 1989-11-13 1991-07-01 Sakai Chem Ind Co Ltd Peroxyniobic acid sol and its production
JPH06321543A (en) * 1993-05-17 1994-11-22 Taki Chem Co Ltd Niobium pentaoxide sol and its production
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Publication number Priority date Publication date Assignee Title
KR20230116777A (en) 2020-12-08 2023-08-04 디아이씨 가부시끼가이샤 Niobium oxide particles and method for producing niobium oxide particles
DE112020007825T5 (en) 2020-12-08 2023-09-28 Dic Corporation NIOBOXIDE PARTICLES AND METHOD FOR PRODUCING NIOBOXIDE PARTICLES

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