JP2000007309A - Production of porous oxide powder - Google Patents
Production of porous oxide powderInfo
- Publication number
- JP2000007309A JP2000007309A JP10172795A JP17279598A JP2000007309A JP 2000007309 A JP2000007309 A JP 2000007309A JP 10172795 A JP10172795 A JP 10172795A JP 17279598 A JP17279598 A JP 17279598A JP 2000007309 A JP2000007309 A JP 2000007309A
- Authority
- JP
- Japan
- Prior art keywords
- emulsion
- powder
- water
- specific surface
- surface area
- 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.)
- Pending
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- Oxygen, Ozone, And Oxides In General (AREA)
- Colloid Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明はアルミナあるいはシ
リカ等の多孔質酸化物粉末の製造方法に関する。The present invention relates to a method for producing a porous oxide powder such as alumina or silica.
【0002】[0002]
【従来の技術】多孔質のアルミナは、各種の担体、吸着
剤、塗料、添加剤として有用である。また、シリカ、ア
ルミナ等のセラミックス原料粉末中には、ボールミル混
合では容易に粉砕されない凝集体が含まれることがあ
る。そのため、アルミナあるいはシリカ等の多孔質酸化
物粉末の製造方法が、従来から数多く提案されている。2. Description of the Related Art Porous alumina is useful as various carriers, adsorbents, paints and additives. In addition, the raw material powder of ceramics such as silica and alumina sometimes contains aggregates that are not easily pulverized by ball mill mixing. Therefore, many methods for producing a porous oxide powder such as alumina or silica have been proposed.
【0003】例えば、特開平1−32196号公報の低
嵩密度アルミナの製造方法の発明(以下第1の従来技術
という。)においては、pH6〜11、50℃以上の条
件で形成されたアルミナヒドロゲルに、アルミナヒドロ
ゲル形成物質を、温度50℃以上及びpH6〜11の条
件下及び硫酸根の共存下で添加し、結晶成長し、疎凝集
体を形成する擬ベーマイトゲルを得ると共に、このベー
マイトゲルを水洗後、噴霧乾燥し、焼成することによ
り、低嵩密度のアルミナを製造している。For example, in the invention of a method for producing low bulk density alumina disclosed in JP-A-1-32196 (hereinafter referred to as a first prior art), an alumina hydrogel formed at a pH of 6 to 11 and at a temperature of 50 ° C. or higher is used. Was added to the mixture under conditions of a temperature of 50 ° C. or higher and a pH of 6 to 11 and in the coexistence of a sulfate group to obtain a pseudo-boehmite gel which crystal-grows and forms a sparse aggregate. After washing with water, spray drying and firing are performed to produce alumina with low bulk density.
【0004】また、特公平1−16773号公報のアル
ミナの製造方法(以下第2の従来技術という。)におい
ては、種子水酸化アルミニウムを含有スラリーを50℃
以上の温度に保持し、沈殿イオンを実質的に含有しない
酸又はアルカリを加えて該水溶液のpHを5以下あるい
は11以下にしたのち、アルミニウムを含有する中和剤
を加えてpH6〜11に調節することを複数回繰り返す
ことを要旨とする。In the method for producing alumina disclosed in Japanese Patent Publication No. 1-17733 (hereinafter referred to as a second prior art), a slurry containing aluminum hydroxide seed is heated to 50 ° C.
The temperature is maintained at the above, and the pH of the aqueous solution is adjusted to 5 or less or 11 or less by adding an acid or alkali substantially containing no precipitated ions, and then adjusted to pH 6 to 11 by adding a neutralizing agent containing aluminum. The main point is to repeat this step a plurality of times.
【0005】さらに、特開平6−285358号公報の
除放性金属酸化物中空微粒子およびその製造方法(以下
第3の従来技術という。)は、一種類又は複数種類の金
属塩を含む溶液を平均液滴が0.1〜500μmの液滴
とし、該液滴をキャリアガスを用いて気液混相の状態で
高温反応炉に送り、該反応炉内部で液滴に含まれる金属
塩を熱分解して多孔質かつ中空構造を有する金属酸化物
中空微粒子を生成した後、該微粒子内部が外側より低い
圧力となる条件下で、一種類または複数種類の液状物質
と該微粒子を接触させることにより、該微粒子の多孔内
部および/または中空部内に液状物質を含有させること
を特徴とする。[0005] Furthermore, in Japanese Patent Application Laid-Open No. 6-285358, the sustained-release metal oxide hollow fine particles and a method for producing the same (hereinafter referred to as a third conventional technique) are disclosed in Japanese Patent Application Laid-Open No. H06-285358. The droplets are 0.1 to 500 μm droplets, and the droplets are sent to a high-temperature reactor in a gas-liquid mixed phase using a carrier gas, and the metal salts contained in the droplets are thermally decomposed inside the reactor. After producing metal oxide hollow fine particles having a porous and hollow structure by contacting the fine particles with one or more kinds of liquid substances under a condition in which the inside of the fine particles is at a lower pressure than the outside, It is characterized in that a liquid substance is contained inside the porous part and / or the hollow part of the fine particles.
【0006】また、特開平9−294929号公報の多
孔性中空粒子及びその製造方法の発明(以下第4の従来
技術という。)では、固形成分を含有する第一の連続相
内に第一の分散相が分散したプライマリーエマルジョン
であって、該第一の連続相中に気体が加圧溶解されるて
いるプライマリーエマルジョンを第2の分散相としこれ
を更に第二の連続相内に分散させることによってセカン
ダリーエマルジョンを製造し、このセカンダリーエマル
ジョンを常圧状態にして中空粒子を形成した後、前記固
化成分を固化させてから前記プライマリーエマルジョン
の前記第一の分散相部分を除去することにより多孔性中
空粒子を製造する方法である。[0006] In the invention of Japanese Patent Application Laid-Open No. 9-294929, the porous hollow particles and the method for producing the same (hereinafter referred to as a fourth prior art), the first continuous phase containing a solid component is contained in the first continuous phase. A primary emulsion in which a dispersed phase is dispersed, in which a gas is dissolved under pressure in the first continuous phase, as a second dispersed phase, which is further dispersed in a second continuous phase. A secondary emulsion is produced by the method, and the secondary emulsion is formed under normal pressure to form hollow particles.The solidified component is solidified, and then the first dispersed phase portion of the primary emulsion is removed. This is a method for producing particles.
【0007】[0007]
【発明が解決しようとする課題】しかしながら、前記第
1の従来技術においては、アルミナヒドロゲルを形成す
るために、pHを6〜11に規制する必要があり、また
疎凝集体を形成する擬ベーマイトゲルを得るため、pH
6〜11の条件で硫酸根共存下で結晶成長する必要があ
り、工程中でのpH制御を伴うと共に、工程自体が極め
て煩雑である。However, in the first prior art, in order to form an alumina hydrogel, it is necessary to regulate the pH to 6 to 11, and a pseudo-boehmite gel which forms a coarse aggregate is required. PH to obtain
It is necessary to grow crystals in the presence of sulfate groups under the conditions of 6 to 11, which involves pH control during the process and the process itself is extremely complicated.
【0008】また、第2の従来技術においても、種子水
酸化アルミニウムを含有する水性スラリーに、酸または
アルカリを加えてpHを5以下あるいは11以上にした
のち、アルミニウムを含有する中和剤を加えてpH6〜
11に調節することを繰り返すものであり、前記第1の
従来技術と同様に、複雑なpH制御を伴うという問題点
がある。さらに、いずれの従来技術も、元素種によって
沈殿pHが異なるため、一般的に複合酸化物粉末合成に
対しては適応しにくい。[0008] In the second prior art, an acid or alkali is added to an aqueous slurry containing seed aluminum hydroxide to adjust the pH to 5 or less or 11 or more, and then a neutralizing agent containing aluminum is added. PH 6 ~
In this case, the pH is repeatedly adjusted to 11, and as in the first conventional technique, there is a problem that complicated pH control is involved. Furthermore, any of the prior arts is generally difficult to apply to the synthesis of a composite oxide powder because the precipitation pH varies depending on the element type.
【0009】噴霧熱分解法を用いる第3の従来技術にお
いては、サブミクロンの粉末を得るために噴霧液滴を小
さく(〜1μm)すると、金属酸化物中空微粒子の生成
効率が悪くなる。逆に効率的な噴霧条件(噴霧液滴〜1
0μm)で、サブミクロンの微細粉末を得ようとする
と、溶液中の金属塩濃度を薄くする必要があり、同様に
効率が悪い。In the third prior art using the spray pyrolysis method, if the size of the spray droplets is small (m1 μm) in order to obtain a submicron powder, the efficiency of forming hollow metal oxide fine particles becomes poor. Conversely, efficient spraying conditions (sprayed droplets to 1
0 μm), it is necessary to reduce the metal salt concentration in the solution to obtain a submicron fine powder, which is similarly inefficient.
【0010】また、第4の従来技術も、工程が多く、プ
ロセスが煩雑であるという欠点がある。さらに、前記第
1〜第4の従来技術の他にも多孔質酸化物粉末の合成法
は多くあるが、いずれもプロセスが煩雑であったり、高
コストであるという問題点があった。[0010] The fourth prior art also has the disadvantage that the number of steps is large and the process is complicated. Furthermore, there are many methods for synthesizing porous oxide powders in addition to the first to fourth prior arts, but there are problems that the processes are complicated and costly.
【0011】本発明は多孔質酸化物粉末の製造方法にお
ける従来技術の前記のごとき問題点を解決するためにな
されたものであって、簡単な方法でしかも低コストで、
高比表面積を有する多孔質酸化物粉末の製造方法を提供
することを目的とする。The present invention has been made to solve the above-mentioned problems of the prior art in a method for producing a porous oxide powder, and is intended to be simple and inexpensive.
An object of the present invention is to provide a method for producing a porous oxide powder having a high specific surface area.
【0012】発明者等は前記課題を解決するため、低コ
ストで簡単にサブミクロンの酸化物粉末を合成する方法
として、エマルジョン燃焼法に着目した。しかし、この
方法は非常に優れた酸化物粉末の合成方法であるが、高
比表面積な多孔質酸化物はこれまで合成できていなかっ
た。例えば、エマルジョン燃焼合成した中空状アルミナ
粉末においても、比表面積は50m2/g程度であり、
溶液法で合成したアルミナよりも小さかった。In order to solve the above-mentioned problems, the present inventors have focused on an emulsion combustion method as a method for easily synthesizing submicron oxide powder at low cost. However, this method is a very excellent method for synthesizing an oxide powder, but a porous oxide having a high specific surface area has not been synthesized so far. For example, the hollow alumina powder synthesized by emulsion combustion also has a specific surface area of about 50 m 2 / g,
It was smaller than alumina synthesized by the solution method.
【0013】そこで、発明者等はさらに研究を重ねた結
果、エマルジョン燃焼法により、酸化物粉末を製造する
場合、燃焼条件等の制御により、酸化物反応の進行を不
十分な状態にすると、個々の結晶粒子表面は完全には酸
化、結合せず、局所的には結晶粒子表面に水酸基、未分
解金属塩等が残留し、このような粉末を水を含有する溶
液と接触させる水処理のプロセスを施すと、残留水酸基
等によって弱く結合していた部分の結合が切れ、粉末表
面に多孔質構造が形成されることを新たに知見して本発
明を完成した。The inventors have further studied and found that, when producing oxide powder by the emulsion combustion method, if the progress of the oxide reaction is made insufficient by controlling the combustion conditions, etc. The surface of the crystal grains does not completely oxidize and bind, leaving hydroxyl groups, undecomposed metal salts, etc. locally on the surface of the crystal grains, and a water treatment process for bringing such powders into contact with a solution containing water. The present inventors have newly found that the bonding of the portion weakly bonded by the residual hydroxyl group or the like is broken when a porous structure is formed on the powder surface, thereby completing the present invention.
【0014】[0014]
【課題を解決するための手段】本発明の多孔質酸化物粉
末の製造方法は、金属塩が溶解した水溶液を有機溶媒お
よび分散剤と混合しw/o型エマルジョンを形成する工
程と、前記w/o型エマルジョンを噴霧、燃焼させ酸化
物粉末を合成する工程と、前記工程で合成された前記酸
化物粉末を水を含有する溶液と接触させる工程とからな
ることを特徴とする。According to the present invention, there is provided a method for producing a porous oxide powder, comprising the steps of: mixing an aqueous solution in which a metal salt is dissolved with an organic solvent and a dispersant to form a w / o emulsion; A step of spraying and burning the / o type emulsion to synthesize oxide powder; and a step of contacting the oxide powder synthesized in the step with a solution containing water.
【0015】上記エマルジョンを噴霧焼成させ合成した
酸化物粉末は、中空状であることが望ましい。エマルジ
ョン燃焼合成した粉末を、水を含有する溶液と接触させ
るプロセス(以下水処理と称する。)による粒子の構造
変化は粒子表面で発生する。従って、粒子体積に対して
表面の占める割合が小さい中実粒子では、水処理による
効果は小さい。一方、エマルジョン燃焼合成した中空状
粒子は表面殻の厚さが非常に薄いため、粒子体積に対し
て表面の占める割合が非常に大きく、水処理による効果
が大きくなる。The oxide powder synthesized by spraying and firing the above emulsion is preferably hollow. The structural change of the particles due to the process of contacting the powder synthesized by emulsion combustion with a solution containing water (hereinafter referred to as water treatment) occurs on the particle surface. Therefore, the effect of the water treatment is small for solid particles in which the ratio of the surface to the particle volume is small. On the other hand, the hollow particles synthesized by emulsion combustion have a very small thickness of the surface shell, so that the ratio of the surface to the particle volume is very large, and the effect of the water treatment is increased.
【0016】合成する酸化物粉末の組成は、特に限定さ
れない。例えば、アルミナ、チタニア、セリア、ジルコ
ニアのような単純酸化物であってもいいし、これらの元
素に1種類以上の元素を添加した例えばスピネルのよう
な複合酸化物でも良い。The composition of the oxide powder to be synthesized is not particularly limited. For example, a simple oxide such as alumina, titania, ceria, and zirconia may be used, or a composite oxide such as spinel in which one or more elements are added to these elements may be used.
【0017】原料として使用する金属塩の種類は限定さ
れない。金属硝酸塩、金属酢酸塩等の水溶性の金属塩で
あれば良い。また、金属塩水溶液の金属塩濃度は限定さ
れない。金属塩の溶解度に応じて、適切な濃度を設定す
れば良い。但し、濃度が極端に薄いと粉末の合成効率が
悪くなり、低コストという本プロセスのメリットが損な
われ、望ましくない。The type of metal salt used as a raw material is not limited. Any water-soluble metal salt such as metal nitrate and metal acetate may be used. The metal salt concentration of the aqueous metal salt solution is not limited. An appropriate concentration may be set according to the solubility of the metal salt. However, if the concentration is extremely low, the efficiency of powder synthesis becomes poor, and the advantage of the present process of low cost is impaired, which is not desirable.
【0018】使用する有機溶媒の種類は限定されない。
ヘキサン、オクタン、ケロシン、ガソリン等のように、
水溶液とw/o型エマルジョンを作製可能な有機溶媒で
あれば良い。使用する分散剤の種類及び添加量は限定さ
れない。カチオン性界面活性剤、アニオン系界面活性
剤、ノニオン系界面活性剤のいずれでも良く、水溶液、
有機溶媒の種類及び必要とする水滴径に応じて、分散剤
の種類および添加量を変化させればよい。The type of the organic solvent used is not limited.
Like hexane, octane, kerosene, gasoline, etc.
Any organic solvent that can produce an aqueous solution and a w / o emulsion may be used. The type and amount of the dispersant used are not limited. Any of a cationic surfactant, an anionic surfactant, and a nonionic surfactant may be used, and an aqueous solution,
What is necessary is just to change the kind and addition amount of a dispersing agent according to the kind of organic solvent and the required water droplet diameter.
【0019】エマルジョン作製時に混合する水溶液成分
と有機溶媒成分との混合比は、特に限定されない。しか
しながら、混合する水の比率が70%を越えると、エマ
ルジョンの分散相と分散媒が転相する場合がある。w/
o型エマルジョンを安定に得るためには、水の比率は7
0%以下が望ましい。The mixing ratio of the aqueous solution component and the organic solvent component to be mixed when preparing the emulsion is not particularly limited. However, when the ratio of the water to be mixed exceeds 70%, the disperse phase of the emulsion and the dispersing medium may be inverted. w /
In order to obtain an o-type emulsion stably, the water ratio should be 7
0% or less is desirable.
【0020】エマルジョン中の水滴径は、分散剤の種類
および添加量によって任意に制御でき、特に限定されな
い。しかしながら、中空状粒子の方が望ましいことを考
慮すれば、水滴径は100nm以上が望ましい。一方、
水滴径が10μmより大きいと、反応場が大きすぎてエ
マルジョン燃焼時に温度分布ができやすく、また燃焼が
不安定となる。従って、水滴径は10μm以下が望まし
い。The diameter of the water droplets in the emulsion can be arbitrarily controlled by the type and amount of the dispersant, and is not particularly limited. However, considering that hollow particles are more desirable, the water droplet diameter is desirably 100 nm or more. on the other hand,
If the water droplet diameter is larger than 10 μm, the reaction field is too large, so that a temperature distribution is easily formed during the combustion of the emulsion, and the combustion becomes unstable. Therefore, the water droplet diameter is desirably 10 μm or less.
【0021】燃焼温度は、エマルジョン中の有機溶媒の
種類および混合比、エマルジョン流量、供給酸素量等に
より制御できる。燃焼温度はとくに限定されないが、6
00〜1000℃が望ましい。600℃以下では燃焼温
度が低すぎて、有機溶媒が完全に燃焼しない恐れがあ
る。一方、1000℃を越えると、金属塩の酸化反応が
完全に進行してしまう場合があり、水処理の効果がなく
なる恐れがある。燃焼雰囲気は特に限定されないが、酸
素が十分でないと、不完全燃焼によって有機溶媒中の炭
素成分が残留するおそれがある。従って、エマルジョン
中の有機溶媒が完全燃焼できる程度の酸素(空気)を供
給することが望ましい。The combustion temperature can be controlled by the type and mixing ratio of the organic solvent in the emulsion, the flow rate of the emulsion, the amount of supplied oxygen, and the like. The combustion temperature is not particularly limited.
00-1000 degreeC is desirable. If the temperature is lower than 600 ° C., the combustion temperature is too low, and the organic solvent may not completely burn. On the other hand, when the temperature exceeds 1000 ° C., the oxidation reaction of the metal salt may proceed completely, and the effect of the water treatment may be lost. The combustion atmosphere is not particularly limited, but if oxygen is not sufficient, carbon components in the organic solvent may remain due to incomplete combustion. Therefore, it is desirable to supply oxygen (air) to such an extent that the organic solvent in the emulsion can be completely burned.
【0022】金属塩の酸化反応は、エマルジョン燃焼合
成時の温度を変化させることにより制御可能である。一
方、必要とする粉末組成、粉末形状等の関係で反応温度
を変化させられない場合も、合成粉末を電気炉で熱処理
することにより、酸化反応の進行状態を制御することが
可能である。この場合の熱処理温度、熱処理時間、熱処
理雰囲気等は特に限定されない。The oxidation reaction of the metal salt can be controlled by changing the temperature at the time of emulsion combustion synthesis. On the other hand, even when the reaction temperature cannot be changed due to the required powder composition, powder shape, and the like, the progress of the oxidation reaction can be controlled by heat-treating the synthetic powder in an electric furnace. The heat treatment temperature, heat treatment time, heat treatment atmosphere and the like in this case are not particularly limited.
【0023】水処理に使用する溶液の種類は、水を含有
するという以外には、特に限定されない。中性の水であ
っても良いし、硝酸、塩酸等の酸性溶液、アンモニア
水、水酸化ナトリウム水溶液等のアルカリ性溶液を用い
ても良い。さらに、これらの溶液とエタノール等の水溶
性有機溶媒を任意の割合で混合した容液であっても良
い。また、水処理温度、水処理時間は特に限定されな
い。これら溶液の種類、水処理温度、水処理時間を変化
させることによって、表面構造の状態を制御することが
できる。水を含有する溶液と接触させる方法について
も、特に限定されない。例えば合成された酸化物粉末を
水を含有する溶液と混合しても良いし、あるいは噴霧さ
れた溶液と接触されても良い。The type of solution used for water treatment is not particularly limited, except that it contains water. Neutral water may be used, or an acidic solution such as nitric acid or hydrochloric acid, or an alkaline solution such as aqueous ammonia or aqueous sodium hydroxide may be used. Further, a solution obtained by mixing these solutions with a water-soluble organic solvent such as ethanol at an arbitrary ratio may be used. Further, the water treatment temperature and the water treatment time are not particularly limited. The state of the surface structure can be controlled by changing the type of the solution, the temperature of the water treatment, and the time of the water treatment. The method of contacting with a solution containing water is not particularly limited. For example, the synthesized oxide powder may be mixed with a solution containing water, or may be contacted with a sprayed solution.
【0024】[0024]
【作用】エマルジョン燃焼法は、w/o型エマルジョン
中の有機溶媒燃焼によって、金属塩を含む水滴の加熱、
水蒸発、金属塩酸化が瞬時に発生する短時間プロセスで
ある。酸化物粒子は1)水滴表面での水蒸発、2)水滴
収縮と水滴表面での結晶子の核生成、3)核生成した結
晶子の成長と焼結、というメカニズムにより合成される
と考えられる。この際、水滴収縮と結晶子焼結の速度等
によって、合成粒子が中実粒子になる場合と、中空粒子
になる場合とがある。The emulsion combustion method heats water droplets containing metal salts by burning an organic solvent in a w / o emulsion.
This is a short-time process in which water evaporation and metal oxidation occur instantaneously. Oxide particles are thought to be synthesized by the following mechanisms: 1) water evaporation on the surface of water droplets, 2) shrinkage of water droplets and nucleation of crystallites on the surface of water droplets, 3) growth and sintering of crystallites that have formed nuclei. . At this time, there are cases where the synthetic particles become solid particles and cases where the synthetic particles become hollow particles depending on the rate of water droplet shrinkage and crystallite sintering.
【0025】合成粉末の組成、有機溶媒の種類、燃焼条
件にもよるが、酸化反応が十分に進行する条件では、水
滴表面で核生成、成長した数十nm以下の酸化物結晶子
同志が完全に結合し、一つの酸化物粒子が合成される。
一方、酸化反応が十分に進行しない場合には、個々の結
晶子表面は完全に酸化、結合しておらず、局所的には結
晶子表面に水酸基、未分解金属塩等が残留する場合があ
ると考えられる。後者の場合、水処理を行うと、残留水
酸基等によって弱く結合していた部分の結合が切れ、粒
子表面に多孔質構造ができると考えられる。Depending on the composition of the synthetic powder, the type of the organic solvent, and the combustion conditions, under conditions where the oxidation reaction proceeds sufficiently, oxide crystallites of several tens of nm or less that have nucleated and grown on the surface of the water droplets are completely removed. And one oxide particle is synthesized.
On the other hand, when the oxidation reaction does not proceed sufficiently, individual crystallite surfaces are not completely oxidized and bonded, and hydroxyl groups, undecomposed metal salts, etc. may remain locally on the crystallite surface. it is conceivable that. In the latter case, it is considered that when the water treatment is performed, the weakly bonded portion is broken by the residual hydroxyl group and the like, and a porous structure is formed on the particle surface.
【0026】[0026]
【発明の実施の形態】(実施例1)市販硝酸アルミニウ
ムをイオン交換水に溶解させて作製した0.1〜2mo
l/Lの硝酸アルミニウム水溶液を水相とした。市販ケ
ロシンを有機溶媒とした。分散剤としては、太陽化学
(株)製サンソフトNo.818Hを用いた。添加量は
ケロシンに対して5〜10wt%とした。この分散剤入
りのケロシンを油相とした。水相と油相を、水相/油相
=50〜70/50〜30(vol%)となるように混
合した。混合溶液をホモジナイザを用いて1000〜2
0000rpmの回転数で5〜30分間攪拌し、w/o
型エマルジョンを得た。光学顕微鏡観察の結果から、エ
マルジョン中の水滴径は約1〜2μmであった。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Example 1) 0.1 to 2 mo prepared by dissolving commercially available aluminum nitrate in ion-exchanged water.
The aqueous phase was 1 / L aluminum nitrate aqueous solution. Commercial kerosene was used as the organic solvent. As the dispersant, sun soft No. manufactured by Taiyo Kagaku Co., Ltd. 818H was used. The addition amount was 5 to 10 wt% with respect to kerosene. The kerosene containing the dispersant was used as an oil phase. The aqueous phase and the oil phase were mixed so that the aqueous phase / oil phase = 50-70 / 50-30 (vol%). Using a homogenizer, the mixed solution was subjected to 1000-2.
The mixture was stirred for 5 to 30 minutes at a rotation speed of 0000 rpm, and w / o
A type emulsion was obtained. From the result of observation with an optical microscope, the diameter of the water droplet in the emulsion was about 1 to 2 μm.
【0027】作製した混合エマルジョンを、エマルジョ
ン燃焼反応装置を用いて噴霧、燃焼させ、酸化物粉末を
合成した。合成は噴霧したエマルジョンが完全燃焼し、
かつ火炎温度が600〜800℃の一定温度になるよう
に、エマルジョン流量、空気量(酸素量)等を制御した
状態で行った。得られた粉末を反応管後部に設置したバ
グフィルタで回収した。TEM観察の結果、この条件で
合成したアルミナ粉末は、表面殻厚さ10〜20nmの
中空状粒子であった。The prepared mixed emulsion was sprayed and burned using an emulsion combustion reactor to synthesize an oxide powder. In the synthesis, the sprayed emulsion burns completely,
In addition, the process was performed while controlling the flow rate of the emulsion, the amount of air (the amount of oxygen), and the like so that the flame temperature became a constant temperature of 600 to 800 ° C. The obtained powder was collected by a bag filter installed at the rear of the reaction tube. As a result of TEM observation, the alumina powder synthesized under these conditions was hollow particles having a surface shell thickness of 10 to 20 nm.
【0028】合成粉末を1〜10gを、イオン交換水1
0〜1000ccと混合した。得られたサスペンション
をマグネチックスターラを用い、常温で1〜240分間
攪拌した。攪拌後のサスペンションを濾過し、更にイオ
ン交換水で数回洗浄した。濾紙に残留した粉末を乾燥、
解砕し、形状観察(SEM)および比表面測定(BE
T)を実施した。図1のSEM写真は本実施例1の水処
理後に得られた粒子構造を示す写真である。1 to 10 g of the synthetic powder was added to 1 part of ion-exchanged water.
0-1000 cc. The obtained suspension was stirred at room temperature for 1 to 240 minutes using a magnetic stirrer. The suspension after stirring was filtered and further washed several times with ion-exchanged water. Dry the powder remaining on the filter paper,
Disintegrate, shape observation (SEM) and specific surface measurement (BE)
T) was performed. The SEM photograph in FIG. 1 is a photograph showing the particle structure obtained after the water treatment in Example 1.
【0029】(比較例1)水処理を行わなかったこと以
外は上記実施例1と同様にして、エマルジョン燃焼合成
した粉末を作製した。この比較例1の粉末につき、実施
例1と同様の評価を行った。図2のSEM写真は水処理
前のエマルジョン燃焼合成粉末の粒子構造を示す写真で
ある。Comparative Example 1 A powder synthesized by emulsion combustion was prepared in the same manner as in Example 1 except that the water treatment was not performed. The same evaluation as in Example 1 was performed on the powder of Comparative Example 1. The SEM photograph in FIG. 2 is a photograph showing the particle structure of the emulsion combustion synthetic powder before the water treatment.
【0030】(試験結果)図2の写真から明らかなよう
に、粒子表面が非常に滑らかであることがわかる。ま
た、粉末の比表面積は46m2/gであった。この値
は、表面殻は滑らか、比表面積測定時に表面殻両側(内
側、外側)に窒素吸着発生、という仮定の基で、1水滴
中のアルミニウムイオン量、合成粉末粒径、表面殻厚
さ、密度から計算した比表面積とほぼ対応していた。従
って、比表面積の点からも粒子表面は滑らかと考えられ
た。それに対して、実施例1の水処理粉末では、図1の
ように滑らかな表面構造が崩れ、数十nmオーダの凹凸
構造が現れていることがわかる。(Test Results) As is clear from the photograph of FIG. 2, it is understood that the particle surface is very smooth. The specific surface area of the powder was 46 m 2 / g. This value is based on the assumption that the surface shell is smooth and nitrogen adsorption occurs on both sides (inside and outside) of the surface shell when measuring the specific surface area, the amount of aluminum ion in one water droplet, the particle size of the synthetic powder, the surface shell thickness, It almost corresponded to the specific surface area calculated from the density. Therefore, the particle surface was considered to be smooth from the viewpoint of the specific surface area. In contrast, in the water-treated powder of Example 1, it can be seen that the smooth surface structure collapsed as shown in FIG. 1 and an uneven structure on the order of several tens of nm appeared.
【0031】(実施例2〜4)実施例2として、実施例
1でエマルジョン燃焼合成した粉末を、水処理溶液をイ
オン交換水から1mol/Lの硝酸水溶液に変更する以
外は、実施例と同じプロセスで水処理および比表面積測
定を行った。実施例3として、実施例1でエマルジョン
燃焼合成した粉末を、水処理溶液をイオン交換水から1
mol/Lのアンモニア水溶液に変更する以外は、実施
例1と同じプロセスで水処理および比表面積測定を行っ
た。実施例4として、実施例1でエマルジョン燃焼合成
した粉末を、水処理溶液をイオン交換水からイオン交換
水、エタノールの混合溶液(体積比で1:1)に変更す
る以外は、実施例1と同じプロセスで水処理および比表
面積測定を行った。(Examples 2 to 4) As Example 2, the same procedure as in Example 1 was carried out except that the powder obtained by the emulsion combustion synthesis in Example 1 was changed from a deionized water treatment solution to a 1 mol / L nitric acid aqueous solution. Water treatment and specific surface area measurement were performed in the process. In Example 3, the powder prepared by the emulsion combustion synthesis in Example 1 was prepared by changing the water treatment solution from ion-exchanged water to 1%.
Water treatment and specific surface area measurement were performed in the same process as in Example 1, except that the aqueous ammonia solution was changed to a mol / L aqueous ammonia solution. Example 4 Example 4 was the same as Example 1 except that the powder obtained by emulsion combustion synthesis in Example 1 was changed from a water treatment solution from ion-exchanged water to a mixed solution of ion-exchanged water and ethanol (1: 1 by volume). Water treatment and specific surface area measurement were performed in the same process.
【0032】(実施例5〜7、比較例2)実施例1で作
製するエマルジョン中の水相を、0.1〜2mol/L
硝酸アルミニウム水溶液から0.1〜2mol/Lの硝
酸アルミニウム、硝酸ナトリウム混合水溶液(混合比;
モル比でNa/Al=1/99)に変更し、Na含有ア
ルミナを実施例1と同じ条件で合成した。なお、合成粉
末は実施例1と同様に表面殻が非常に薄い中空状粒子で
あった。得られた合成粉末のうちその後の水処理を行わ
ない合成粉末を比較例2とし比表面積を測定し、実施例
5〜7として得られた合成粉末にそれぞれ下記の水処理
を施した後、比表面積を測定した。(Examples 5 to 7, Comparative Example 2) The aqueous phase in the emulsion prepared in Example 1 was changed to 0.1 to 2 mol / L.
0.1 to 2 mol / L aluminum nitrate and sodium nitrate mixed aqueous solution (mixing ratio;
The molar ratio was changed to Na / Al = 1/99), and Na-containing alumina was synthesized under the same conditions as in Example 1. The synthetic powder was hollow particles having a very thin surface shell as in Example 1. Of the obtained synthetic powders, a synthetic powder not subjected to the subsequent water treatment was used as Comparative Example 2 to measure the specific surface area, and the synthetic powders obtained as Examples 5 to 7 were subjected to the following water treatments, respectively. The surface area was measured.
【0033】実施例5として、この合成粉末を実施例1
と同じく、イオン交換水を用いて水処理し、比表面積測
定を行った。実施例6として、この合成粉末を実施例2
と同じく、1mol/Lの硝酸水溶液を用いて水処理
し、比表面積測定を行った。実施例7として、この合成
粉末を実施例3と同じく、1mol/Lのアンモニア水
溶液を用いて水処理し、比表面積測定を行った。In Example 5, this synthetic powder was used in Example 1.
Water treatment was carried out using ion-exchanged water, and the specific surface area was measured. In Example 6, this synthetic powder was used in Example 2.
Water treatment was performed using a 1 mol / L nitric acid aqueous solution in the same manner as described above, and the specific surface area was measured. As Example 7, this synthetic powder was treated with a 1 mol / L aqueous ammonia solution as in Example 3, and the specific surface area was measured.
【0034】(実施例8〜10、比較例3)実施例1で
作製するエマルジョン中の水相を、0.1〜2mol/
Lの硝酸アルミニウム水溶液から0.1〜2mol/L
の硝酸アルミニウム、硝酸マグネシウム混合水溶液(混
合比:モル比でMg/Al=1/99)に変更し、Mg
含有アルミナを実施例1と同じ条件で合成した。なお、
合成粉末は実施例1と同様、表面殻が非常に薄い中空状
粒子であった。得られた合成粉末の一部を比較例3とし
比表面積を測定し、残余の合成粉末に対して、下記のご
とき水処理を施し、実施例8〜10として比表面積を測
定した。(Examples 8 to 10, Comparative Example 3) The aqueous phase in the emulsion prepared in Example 1 was adjusted to 0.1 to 2 mol /
0.1 to 2 mol / L from aluminum nitrate aqueous solution
Was changed to a mixed aqueous solution of aluminum nitrate and magnesium nitrate (mixing ratio: molar ratio: Mg / Al = 1/99).
The contained alumina was synthesized under the same conditions as in Example 1. In addition,
As in Example 1, the synthetic powder was hollow particles having a very thin surface shell. A part of the obtained synthetic powder was used as Comparative Example 3 to measure the specific surface area. The remaining synthetic powder was subjected to the following water treatment, and the specific surface area was measured as Examples 8 to 10.
【0035】すなわち、実施例8として、得られた合成
粉末を、実施例1と同じく、イオン交換水を用いて水処
理し、比表面積測定を行った。実施例9として、得られ
た合成粉末を実施例2と同じく、1mol/Lの硝酸水
溶液を用いて水処理し、比表面積測定を行った。実施例
10として、得られた合成粉末を、実施例3と同じく、
1mol/Lのアンモニア水溶液を用いて水処理し、比
表面積測定を行った。以上の実施例1〜10および比較
例1〜3で測定された比表面積を表1にまとめて示し
た。That is, as Example 8, the obtained synthetic powder was treated with ion-exchanged water as in Example 1, and the specific surface area was measured. As Example 9, the obtained synthetic powder was treated with a 1 mol / L aqueous nitric acid solution as in Example 2, and the specific surface area was measured. As Example 10, the obtained synthetic powder was prepared in the same manner as in Example 3.
Water treatment was performed using a 1 mol / L aqueous ammonia solution, and the specific surface area was measured. Table 1 collectively shows the specific surface areas measured in the above Examples 1 to 10 and Comparative Examples 1 to 3.
【0036】[0036]
【表1】 [Table 1]
【0037】表1に示したように、本発明の実施例であ
る実施例1〜10の水処理後粉末の比表面積は、比較例
である比較例1〜3の水処理前粉末の比表面積と比較し
て飛躍的に向上していることがわかる。実施例2〜10
の粉末をSEM観察したところ、粉末組成、水処理条件
によって程度に差はあるが、実施例1と同様、表面構造
の崩れが観察された。また、実施例4のように、水、ア
ルコールの混合溶液では、粉末と水との接触の機会が少
ないために、表面構造の崩れが小さく、水のみで処理す
る場合と比較して比表面積増加が小さいことがわかる。
これは、水、アルコールの混合比変更によって表面構造
を制御し、未処理品と水処理品の間で任意の比表面積が
得られることを意味する。更に、原因は明らかでない
が、実施例の範囲ではアンモニア水溶液処理品>イオン
交換水処理品>硝酸水溶液処理品の順に比表面積は大き
かった。これは、水処理に用いる溶液pHによっても比
表面積が制御可能であることを意味する。As shown in Table 1, the specific surface areas of the powders after water treatment of Examples 1 to 10 which are examples of the present invention are the specific surface areas of the powders before water treatment of Comparative Examples 1 to 3 which are comparative examples. It can be seen that it is dramatically improved as compared with. Examples 2 to 10
When the powder was observed by SEM, the surface structure was broken as in Example 1, although the degree varied depending on the powder composition and water treatment conditions. Further, as in Example 4, in the mixed solution of water and alcohol, since the chance of contact between the powder and water is small, the collapse of the surface structure is small, and the specific surface area is increased as compared with the case of treating only with water. Is small.
This means that the surface structure is controlled by changing the mixing ratio of water and alcohol, and an arbitrary specific surface area can be obtained between the untreated product and the water-treated product. Further, although the cause is not clear, the specific surface area was larger in the order of the aqueous ammonia treated product> the ion-exchanged water treated product> the nitric acid aqueous solution treated product in the range of the examples. This means that the specific surface area can be controlled by the pH of the solution used for the water treatment.
【0038】(実施例11〜14)実施例1で合成した
アルミナ粉末を、電気炉を用いて700〜1000℃の
温度で大気中4時間の熱処理を実施した。熱処理後の粉
末に対して、実施例と同じく、イオン交換水を用いて水
処理し、比表面積測定を行った。表2に測定した比表面
積を示す。なお、各実施例での熱処理温度は、実施例1
1では700℃、実施例12では800℃、実施例13
では900℃、実施例14では1000℃であった。(Examples 11 to 14) The alumina powder synthesized in Example 1 was subjected to a heat treatment in an atmosphere at a temperature of 700 to 1000 ° C. for 4 hours using an electric furnace. The powder after the heat treatment was subjected to water treatment using ion-exchanged water and the specific surface area was measured as in the example. Table 2 shows the measured specific surface areas. Note that the heat treatment temperature in each example is the same as that in Example 1.
1, 700 ° C., Example 12 at 800 ° C., Example 13
In Example 14, the temperature was 900 ° C., and in Example 14, the temperature was 1000 ° C.
【0039】[0039]
【表2】 [Table 2]
【0040】表2のように、いずれの熱処理後粉末でも
水処理によって比表面積が向上することがわかる。ま
た、熱処理温度上昇と共に水処理後粉末の比表面積が低
下している。実施例11〜14の粉末をSEM観察した
ところ、熱処理条件によって程度に差はあるが、実施例
1と同様、表面構造の崩れが観察された。但し、熱処理
温度の上昇と共に、表面構造の崩れは小さくなり、比較
例1の状態(図2)に近ずく傾向にあった。これは、熱
処理によって酸化反応が一部進行し、結晶子表面に残留
した水酸基、未分解金属塩等が減少し、表面構造が崩れ
にくくなるためと考えられた。この結果は、合成後の熱
処理によっても表面構造の制御が可能であり、未処理品
と水処理品の間であれば任意の任意の比表面積が得られ
ることを意味する。As shown in Table 2, it is found that the specific surface area of any of the powders after the heat treatment is improved by the water treatment. In addition, the specific surface area of the powder after water treatment decreases as the heat treatment temperature increases. When the powders of Examples 11 to 14 were observed by SEM, collapse of the surface structure was observed as in Example 1, although the degree varied depending on the heat treatment conditions. However, as the heat treatment temperature increased, the collapse of the surface structure became smaller and tended to approach the state of Comparative Example 1 (FIG. 2). It is considered that this is because the oxidation reaction partially progressed by the heat treatment, the hydroxyl groups, undecomposed metal salts, and the like remaining on the crystallite surface were reduced, and the surface structure was less likely to collapse. This result means that the surface structure can be controlled also by heat treatment after synthesis, and any arbitrary specific surface area can be obtained between the untreated product and the water-treated product.
【0041】[0041]
【発明の効果】本発明の多孔質酸化物粉末の製造方法
は、金属塩が溶解した水溶液を有機溶媒および分散剤と
混合しw/o型エマルジョンを形成する工程と、前記w
/o型エマルジョンを噴霧、燃焼させ酸化物粉末を合成
する工程において、エマルジョンの噴霧、燃焼条件を適
宜に選択することにより、酸化反応の進行が不十分な状
態の酸化物粒子が得られる。この工程で合成された酸化
物粒子を水を含有する溶液と接触させる工程により、こ
の合成粒子の結晶子表面に残留する水酸基、未分解金属
塩の結合が切れ、粉末表面に多孔質構造が出現するた
め、比表面積が飛躍的に向上する。また、燃焼条件、水
溶液の種類等によって、比表面積が制御可能である。According to the method for producing a porous oxide powder of the present invention, a step of mixing an aqueous solution in which a metal salt is dissolved with an organic solvent and a dispersant to form a w / o emulsion,
In the step of spraying and burning the / o type emulsion to synthesize the oxide powder, by appropriately selecting the spraying and burning conditions of the emulsion, oxide particles in which the progress of the oxidation reaction is insufficient can be obtained. The step of contacting the oxide particles synthesized in this step with a solution containing water breaks the bonds of hydroxyl groups and undecomposed metal salts remaining on the crystallite surface of the synthesized particles, and a porous structure appears on the powder surface As a result, the specific surface area is dramatically improved. Further, the specific surface area can be controlled by the combustion conditions, the type of the aqueous solution, and the like.
【図1】本発明方法で得られた多孔質酸化物粒子の粒子
構造を表すSEM写真である。FIG. 1 is an SEM photograph showing the particle structure of a porous oxide particle obtained by the method of the present invention.
【図2】本発明方法の水処理前を実施しない酸化物粒子
の粒子構造を表すSEM写真である。FIG. 2 is an SEM photograph showing a particle structure of an oxide particle which is not subjected to a water treatment according to the method of the present invention.
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成10年8月18日(1998.8.1
8)[Submission date] August 18, 1998 (1998.8.1)
8)
【手続補正1】[Procedure amendment 1]
【補正対象書類名】図面[Document name to be amended] Drawing
【補正対象項目名】図1[Correction target item name] Fig. 1
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【図1】 FIG.
【手続補正2】[Procedure amendment 2]
【補正対象書類名】図面[Document name to be amended] Drawing
【補正対象項目名】図2[Correction target item name] Figure 2
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【図2】 FIG. 2
───────────────────────────────────────────────────── フロントページの続き (72)発明者 神谷 信雄 愛知県愛知郡長久手町大字長湫字横道41番 地の1株式会社豊田中央研究所内 Fターム(参考) 4G042 DA01 DB09 DC03 DE14 4G065 AA01 AA06 AA07 AB03X AB32X BA07 BB03 BB06 CA04 CA21 DA04 FA01 4G076 AA02 AB07 BA06 CA12 DA01 DA23 DA25 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Nobuo Kamiya Inventor F-term (reference) in Toyota Central Research Institute, Inc. 41 No. 41, Chukumi Yokomichi, Nagakute-cho, Aichi-gun, Aichi (reference) 4G042 DA01 DB09 DC03 DE14 4G065 AA01 AA06 AA07 AB03X AB32X BA07 BB03 BB06 CA04 CA21 DA04 FA01 4G076 AA02 AB07 BA06 CA12 DA01 DA23 DA25
Claims (1)
び分散剤と混合しw/o型エマルジョンを形成する工程
と、前記w/o型エマルジョンを噴霧、燃焼させ酸化物
粉末を合成する工程と、前記工程で合成された前記酸化
物粉末を水を含有する溶液と接触させる工程とからなる
ことを特徴とする多孔質酸化物粉末の製造方法。1. A step of mixing an aqueous solution in which a metal salt is dissolved with an organic solvent and a dispersant to form a w / o emulsion, and a step of spraying and burning the w / o emulsion to synthesize an oxide powder. Contacting the oxide powder synthesized in the above step with a solution containing water.
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JP10172795A JP2000007309A (en) | 1998-06-19 | 1998-06-19 | Production of porous oxide powder |
US09/166,122 US6004525A (en) | 1997-10-06 | 1998-10-05 | Hollow oxide particle and process for producing the same |
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JP10172795A JP2000007309A (en) | 1998-06-19 | 1998-06-19 | Production of porous oxide powder |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001316112A (en) * | 2000-03-16 | 2001-11-13 | Symmetrics Corp | Liquid precursor for aluminum oxide and its manufacturing method |
JP2008535750A (en) * | 2005-02-15 | 2008-09-04 | メルク パテント ゲゼルシャフト ミット ベシュレンクテル ハフトング | Process for producing spherical mixed oxide powders in a hot wall reactor |
US7696127B2 (en) | 2006-01-13 | 2010-04-13 | Toda Kogyo Corporation | Exhaust gas purifying catalyst |
JP2011016718A (en) * | 2010-09-06 | 2011-01-27 | Kyocera Corp | Inorganic hollow powder and method for manufacturing the same |
CN102989508A (en) * | 2012-11-21 | 2013-03-27 | 北京大学深圳研究生院 | Synthesizing method and application of polymer microsphere immobilized palladium nanometer particles |
-
1998
- 1998-06-19 JP JP10172795A patent/JP2000007309A/en active Pending
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001316112A (en) * | 2000-03-16 | 2001-11-13 | Symmetrics Corp | Liquid precursor for aluminum oxide and its manufacturing method |
JP2008535750A (en) * | 2005-02-15 | 2008-09-04 | メルク パテント ゲゼルシャフト ミット ベシュレンクテル ハフトング | Process for producing spherical mixed oxide powders in a hot wall reactor |
US7696127B2 (en) | 2006-01-13 | 2010-04-13 | Toda Kogyo Corporation | Exhaust gas purifying catalyst |
JP2011016718A (en) * | 2010-09-06 | 2011-01-27 | Kyocera Corp | Inorganic hollow powder and method for manufacturing the same |
CN102989508A (en) * | 2012-11-21 | 2013-03-27 | 北京大学深圳研究生院 | Synthesizing method and application of polymer microsphere immobilized palladium nanometer particles |
CN102989508B (en) * | 2012-11-21 | 2015-12-09 | 北京大学深圳研究生院 | The preparation method and use of the Pd nano particle that a kind of polymer microballoon is immobilized |
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