JP5987778B2 - Method for producing rare earth oxide powder - Google Patents
Method for producing rare earth oxide powder Download PDFInfo
- Publication number
- JP5987778B2 JP5987778B2 JP2013096378A JP2013096378A JP5987778B2 JP 5987778 B2 JP5987778 B2 JP 5987778B2 JP 2013096378 A JP2013096378 A JP 2013096378A JP 2013096378 A JP2013096378 A JP 2013096378A JP 5987778 B2 JP5987778 B2 JP 5987778B2
- Authority
- JP
- Japan
- Prior art keywords
- rare earth
- oxide powder
- solution
- earth oxide
- precipitate
- 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.)
- Active
Links
Description
本発明は、粒径が大きく、かつ比表面積の大きな希土類酸化物粉末の製造方法に関する。 The present invention relates to a method for producing a rare earth oxide powder having a large particle size and a large specific surface area.
希土類酸化物は、その特性から三元触媒、ガスセンサ、酸素貯蔵材料、水素吸蔵合金等に用いられている。一般的にこれらの用途として用いられるには、触媒等である希土類酸化物と反応ガス等の接触面積が増大するほど特性が向上することが知られている。即ち、比表面積の大きな希土類粉末が特性上重要な因子となる。ナノメーターサイズの粒子径を有する粉末の製造方法として、気相法では噴霧熱分解、ＣＶＤ法等が知られており、液相法として、均一沈殿法、ゾルゲル法、逆ミセル法、水熱合成法等が知られている。 Rare earth oxides are used for three-way catalysts, gas sensors, oxygen storage materials, hydrogen storage alloys and the like because of their characteristics. In general, for use in these applications, it is known that the characteristics improve as the contact area between a rare earth oxide as a catalyst and a reactive gas increases. That is, a rare earth powder having a large specific surface area is an important factor in characteristics. As a method for producing a powder having a nanometer size particle size, spray pyrolysis, CVD method, etc. are known in the gas phase method, and homogeneous precipitation method, sol-gel method, reverse micelle method, hydrothermal synthesis are known as liquid phase methods. Laws are known.
しかしながら、ナノメーターサイズの微粒子は静電的引力等によって凝集性、付着性が強く、分散状態を維持することは困難であり、凝集により粒度分布に大きなばらつきを生じる。また、このような微粒子は活性なため、高温状態では微粒子は互いに焼結や粒成長を起こす可能性がある。また、このような凝集は強固であり粉砕は容易でない。これらが例えば触媒反応などの特性の不安定性につながり、特性上望ましくはない。更に、このような微粒子は嵩密度が小さく取り扱いが困難であり、取り扱い上問題となることがあることから、希土類酸化物粉末には分散性、流動性、取り扱いの容易さ等が求められる。 However, nanometer-sized fine particles have strong cohesiveness and adhesion due to electrostatic attraction and the like, and it is difficult to maintain a dispersed state, and the particle size distribution varies greatly due to aggregation. In addition, since such fine particles are active, the fine particles may cause sintering and grain growth at high temperatures. Further, such aggregation is strong and pulverization is not easy. These lead to instability of characteristics such as catalytic reaction, and are not desirable in characteristics. Further, since such fine particles have a small bulk density and are difficult to handle and may cause problems in handling, the rare earth oxide powder is required to have dispersibility, fluidity, ease of handling, and the like.
粒子径が数十ミクロンの巨大な粒子は取り扱いが容易である一方、このような粒子を製造するためには沈殿法などに代表される液相法では熟成時間を長くしたり、一度回収した粒子を種として再度成長させたり、時間や更なる工程が必要となる。また、大きな粒子をボールミル等で粉砕する方法では粒子形状と粒子径を制御することは困難であり、気相法では大きな粒子を得ることが困難である。更に、このような巨大粒子は一般的に比表面積が小さく、触媒等の用途には望ましくない。
なお、本発明に関連する従来技術として、下記文献が挙げられる。
Large particles with a particle size of several tens of microns are easy to handle, but in order to produce such particles, the liquid phase method represented by the precipitation method has a longer aging time or once recovered particles. It is necessary to grow the seeds again as seeds, time and further processes. Further, it is difficult to control the particle shape and particle size by a method of pulverizing large particles with a ball mill or the like, and it is difficult to obtain large particles by a gas phase method. Furthermore, such large particles generally have a small specific surface area and are not desirable for applications such as catalysts.
In addition, the following literature is mentioned as a prior art relevant to this invention.
例えば、［特許文献１］においては凝集がなく焼成後の解砕分散性の良いナノメーターサイズの希土類酸化物微粉末の製造方法が開示されているがプロセス中において固形分濃度を０．０５ｍｏｌ／Ｌ以下とするため量産性が問題となる。また、［特許文献２］においては粒子径が小さく、比表面積の大きな希土類酸化物粒子が得られるが密封容器内で加熱処理を行なうため工業的には圧力容器等の専用の設備が必要となり従来の溶液を混合する設備では製造できない。 For example, [Patent Document 1] discloses a method for producing nanometer-sized rare earth oxide fine powder that has no aggregation and good disintegration and dispersibility after firing. Since it is L or less, mass productivity becomes a problem. In [Patent Document 2], rare earth oxide particles having a small particle diameter and a large specific surface area can be obtained. However, since heat treatment is performed in a sealed container, a dedicated facility such as a pressure container is required industrially. It cannot be manufactured with equipment that mixes these solutions.
本発明は、上記事情に鑑みなされたもので、粒子径が大きい上、比表面積も大きく、凝集が殆んどなく、流動性が良好で、取扱いが容易な希土類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 in view of the above circumstances, and provides a method for producing a rare earth oxide powder having a large particle size, a large specific surface area, almost no aggregation, good fluidity, and easy handling. The purpose is to do.
本発明者は、上記目的を達成するため鋭意検討を重ねた結果、希土類イオンを含有する溶液に沈殿試薬を添加し、生成した難溶性の沈殿物を焼成して希土類酸化物粉末を製造するに際し、上記沈殿試薬として尿素及びヘキサメチレンテトラミンを１：０．１〜１：１０のモル比で併用することにより、平均粒子径が１０〜１００μｍで、ＢＥＴ比表面積が１０〜５０ｍ2／ｇである、凝集が殆んどなく、流動性に優れた希土類酸化物粉末が得られることを知見し、本発明をなすに至った。 As a result of intensive studies to achieve the above object, the present inventor added a precipitation reagent to a solution containing rare earth ions, and calcined the poorly soluble precipitate produced to produce a rare earth oxide powder. By using urea and hexamethylenetetramine as a precipitation reagent in a molar ratio of 1: 0.1 to 1:10, the average particle size is 10 to 100 μm and the BET specific surface area is 10 to 50 m 2 / g. The inventors have found that rare earth oxide powders having almost no aggregation and excellent fluidity can be obtained, and the present invention has been made.
従って、本発明は下記希土類酸化物粉末の製造方法を提供する。
〔１〕
希土類イオンを０．０５〜０．５ｍｏｌ／Ｌ含有する溶液に沈殿剤として尿素及びヘキサメチレンテトラミンを１：０．１〜１：１０のモル比で添加し、８０℃以上沸点以下に加熱し、その加熱温度で３０分〜４時間維持して熟成させ、生成する難溶性の沈殿物を焼成することを特徴とする、平均粒子径が１０〜１００μｍでＢＥＴ比表面積が１０〜５０ｍ2／ｇである希土類酸化物粉末の製造方法。
〔２〕
希土類イオンのモル数と尿素とヘキサメチレンテトラミンを合計した沈殿剤のモル数が、希土類イオンモル数：沈殿剤モル数＝１：５〜１：３０の割合である〔１〕記載の希土類酸化物粉末の製造方法。
〔３〕
焼成温度が６００〜１，２００℃であり、焼成雰囲気が大気雰囲気である〔１〕又は〔２〕記載の希土類酸化物粉末の製造方法。
〔４〕
希土類イオンが、Ｙ、Ｚｒ、Ｈｆ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ及びＬｕイオンから選ばれる１種類又は２種類以上であることを特徴とする〔１〕〜〔３〕のいずれかに記載の希土類酸化物粉末の製造方法。
Accordingly, the present invention provides the following method for producing a rare earth oxide powder.
[1]
Adding urea and hexamethylenetetramine as a precipitating agent in a molar ratio of 1: 0.1 to 1:10 to a solution containing 0.05 to 0.5 mol / L of rare earth ions, and heating to 80 ° C. or more and boiling point or less, An average particle size of 10 to 100 μm and a BET specific surface area of 10 to 50 m 2 / g are characterized by aging and maintaining the heating temperature for 30 minutes to 4 hours and firing the hardly soluble precipitate produced. A method for producing a rare earth oxide powder.
[2]
The rare earth oxide powder according to [1], wherein the number of moles of rare earth ions and the number of moles of the precipitating agent obtained by adding urea and hexamethylenetetramine is a ratio of the rare earth ions mole number: the precipitant mole number = 1: 5 to 1:30. Manufacturing method.
[3]
The method for producing a rare earth oxide powder according to [1] or [2], wherein the firing temperature is 600 to 1,200 ° C., and the firing atmosphere is an air atmosphere.
[4]
The rare earth ions are one or more selected from Y, Zr, Hf, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu ions. The method for producing a rare earth oxide powder according to any one of [1] to [3].
本発明により、粒子径が大きいにも拘らず、比表面積の大きい、凝集が殆んどなく、流動性が良く、取り扱いが容易な球状希土類粉末を製造することができる。 According to the present invention, it is possible to produce a spherical rare earth powder having a large specific surface area, almost no aggregation, good fluidity and easy handling despite its large particle diameter.
以下に本発明の詳細を説明する。
本発明に使用する希土類イオンを含む溶液は、例えば希土類酸化物粉末を硝酸、塩酸、酢酸等の酸に加え、加熱還流することにより溶解させることで得られる。使用する酸は特に制限されないが、不純物の混入や溶解速度から硝酸を用いることが望ましい。また、希土類硝酸塩等の希土類元素の塩を純水に溶解させても良い。希土類イオン中に含まれる希土類元素は、Ｙ、Ｚｒ、Ｈｆ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ及びＬｕから選ばれる１種類又は２種類以上から目的に合わせて適宜選択できる。
Details of the present invention will be described below.
The solution containing rare earth ions used in the present invention can be obtained, for example, by adding rare earth oxide powder to an acid such as nitric acid, hydrochloric acid or acetic acid and dissolving it by heating under reflux. Although the acid to be used is not particularly limited, it is desirable to use nitric acid because of the mixing of impurities and the dissolution rate. Further, a salt of a rare earth element such as a rare earth nitrate may be dissolved in pure water. The rare earth element contained in the rare earth ions is one or two selected from Y, Zr, Hf, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. It can be appropriately selected according to the purpose from more than types.
溶液中の希土類イオン濃度は０．０１〜１ｍｏｌ／Ｌが望ましく、特に０．０５〜０．５ｍｏｌ／Ｌが特に望ましい。希土類イオン濃度が０．０１ｍｏｌ／Ｌ未満では回収される希土類酸化物粉末量が少なく、効率的でない、また、希土類イオン濃度が１ｍｏｌ／Ｌを超えると、凝集等が発生し易くなる場合がある。 The rare earth ion concentration in the solution is preferably 0.01 to 1 mol / L, and particularly preferably 0.05 to 0.5 mol / L. If the rare earth ion concentration is less than 0.01 mol / L, the amount of recovered rare earth oxide powder is small, which is not efficient, and if the rare earth ion concentration exceeds 1 mol / L, aggregation or the like is likely to occur.
本発明では、希土類イオンを含む溶液に、沈殿剤として少なくとも尿素及びヘキサメチレンテトラミンを添加する。沈殿剤として、尿素及びヘキサメチレンテトラミンの他に、クエン酸アンモニウムのようなキレート剤などの試薬を加えても良く、また沈殿剤の他に、界面活性剤等の添加物を目的に応じ加えて良い。
該沈殿剤である尿素とヘキサメチレンテトラミンの割合は、モル比で尿素：ヘキサメチレンテトラミン＝１：０．１〜１：１０が好ましく、特に１：０．２〜１：５が好ましい。１：０．１〜１：１０より尿素の量を多くしたりヘキサメチレンテトラミンの量を多くしたりすると球形の粒子が得にくくなり、凝集しやすく、形状が不揃いになりやすく、また比表面積が小さくなるため好ましくない。
In the present invention, at least urea and hexamethylenetetramine are added as precipitants to a solution containing rare earth ions. As a precipitating agent, in addition to urea and hexamethylenetetramine, a reagent such as a chelating agent such as ammonium citrate may be added. In addition to the precipitating agent, an additive such as a surfactant is added depending on the purpose. good.
The molar ratio of urea and hexamethylenetetramine as the precipitant is preferably urea: hexamethylenetetramine = 1: 0.1 to 1:10, particularly preferably 1: 0.2 to 1: 5. Increasing the amount of urea or increasing the amount of hexamethylenetetramine from 1: 0.1 to 1:10 makes it difficult to obtain spherical particles, tends to agglomerate, tends to be irregular in shape, and has a specific surface area. Since it becomes small, it is not preferable.
希土類イオンに対する沈殿剤の添加量が少ないと収率が低下するおそれがある。また必要以上に多くしても効果は変わらないため、添加する沈殿剤の量は、尿素とヘキサメチレンテトラミンを合計したモル数が溶液中の希土類イオンのモル数に対し、希土類イオンモル数：沈殿剤モル数＝１：１〜１：５０の範囲が好ましく、特に１：５〜１：３０であることが好ましい。 If the amount of the precipitant added to the rare earth ions is small, the yield may decrease. In addition, since the effect does not change even if it is increased more than necessary, the amount of the precipitating agent to be added is the number of moles of rare earth ions: the number of moles of urea and hexamethylenetetramine combined with respect to the number of moles of rare earth ions in the solution. The number of moles is preferably in the range of 1: 1 to 1:50, particularly preferably 1: 5 to 1:30.
上記希土類イオンを含有する溶液を撹拌しながら湯浴により室温から８０℃以上沸点以下に加熱することで尿素並びにヘキサメチレンテトラミンを加水分解させ、溶液中でアンモニアを発生させることにより、溶液中のｐＨが上昇し、希土類元素の難溶性の沈殿を生成させる。８０℃未満ではヘキサメチレンテトラミンは部分的に加水分解を起こすが、尿素はほとんど加水分解を起こさず、本発明の効果が得られない。 By heating the solution containing the rare earth ions from room temperature to 80 ° C. to the boiling point with a hot water bath while stirring, the urea and hexamethylenetetramine are hydrolyzed to generate ammonia in the solution, thereby generating a pH in the solution. As a result, a rare-earth element hardly soluble precipitate is formed. Below 80 ° C, hexamethylenetetramine partially hydrolyzes, but urea hardly hydrolyzes, and the effects of the present invention cannot be obtained.
溶液が８０℃以上に達したら溶液温度を８０℃以上に維持したまま熟成させる。得られる粉末の粒子径は熟成時間を長くするほど大きくなり、熟成時間は目標とする粒子径に応じ適宜選択できるが熟成時間が短いと粒径が揃いにくく、熟成時間が長くなると凝集が起こる可能性があるため、熟成時間は３０分〜４時間が好ましい。 When the solution reaches 80 ° C. or higher, the solution is aged while maintaining the solution temperature at 80 ° C. or higher. The particle size of the resulting powder increases as the aging time increases, and the aging time can be appropriately selected according to the target particle size. However, when the aging time is short, the particle size is difficult to be aligned, and when the aging time is long, aggregation can occur. The aging time is preferably 30 minutes to 4 hours because of its properties.
該溶液を固液分離することで沈殿を回収する。固液分離の方法としては濾過や遠心分離等を用いてもよく、特に制限されない。 The precipitate is recovered by solid-liquid separation of the solution. As a method of solid-liquid separation, filtration, centrifugation, or the like may be used, and there is no particular limitation.
固液分離により回収された沈殿物を乾燥させる。乾燥方法は特に制限されず、オーブンや真空乾燥機などが例示される。 The precipitate recovered by solid-liquid separation is dried. The drying method is not particularly limited, and examples thereof include an oven and a vacuum dryer.
乾燥させた沈殿物を６００〜１，２００℃で２〜５時間焼成することで該沈殿物を熱分解し、これにより希土類酸化物粉末が得られる。焼成時間は２時間未満では熱分解が不完全になる場合があるので２時間以上が好ましく、長時間行なっても効果はないため工程にかかる時間をできるだけ短縮する目的から５時間以下であることが好ましい。焼成温度は６００℃未満では完全に酸化物にならない場合があり、また１，２００℃を超える温度では酸化物は完全に生成されており、これ以上温度を上げても効果がなく、比表面積を減少させるだけとなる。また、焼成雰囲気は大気、真空、Ａｒガス等の不活性ガス等目的に応じ適宜選択できる。 The dried precipitate is fired at 600 to 1,200 ° C. for 2 to 5 hours to thermally decompose the precipitate, thereby obtaining a rare earth oxide powder. If the firing time is less than 2 hours, thermal decomposition may be incomplete, so 2 hours or more is preferable. Since there is no effect even if it is performed for a long time, it should be 5 hours or less for the purpose of shortening the time required for the process as much as possible. preferable. When the firing temperature is less than 600 ° C., the oxide may not be completely formed, and when the temperature exceeds 1,200 ° C., the oxide is completely generated. It will only decrease. The firing atmosphere can be appropriately selected according to the purpose such as air, vacuum, inert gas such as Ar gas.
こうして得られた該希土類酸化物粉末の粒子形状、粒子径を走査型電子顕微鏡（ＳＥＭ）により確認すると、球状で平均粒子径が６８μｍであり、ＢＥＴ法により測定した比表面積が１０〜５０ｍ2／ｇである。該球状粒子の内部が花弁状の内部構造を有しているため粒子径が大きいにも拘らず、大きな比表面積を有することができることが本発明の特徴である。
なお、平均粒子径は該粉末を水を溶媒として分散させたスラリーをレーザー散乱回折法（日機装（株）製 ＭｉｃｒｏｔｒａｃＭＴ３０００ ＩＩ）により求めた。
また、本発明における比表面積は公知の技術であるＢＥＴ（Ｂｒｕｎａｕｅｒ−Ｅｍｍｅｔｔ−Ｔｅｌｌｅｒ）法により求められる比表面積を意味する。
本発明により得られる希土類酸化物粉末は流動性が良く、取り扱いが容易な巨大粒子でありながら比表面積が大きいという微粒子と巨大粒子の両方の長所を合わせ持つ。従って、本発明の希土類酸化物粉末は、このような特性を有することで三元触媒、ガスセンサ、酸素貯蔵材料、水素吸蔵合金等の用途に適しており、また特殊な内部構造を有することからセラミックス内部の微細構造を制御できるためセラミックス原料としても好適である。
When the particle shape and particle diameter of the rare earth oxide powder thus obtained were confirmed by a scanning electron microscope (SEM), it was spherical and the average particle diameter was 68 μm, and the specific surface area measured by the BET method was 10 to 50 m 2 / g. Since the spherical particles have a petal-like internal structure, it is a feature of the present invention that a large specific surface area can be obtained despite the large particle diameter.
The average particle size was determined by a laser scattering diffraction method (Microtrac MT3000 II, manufactured by Nikkiso Co., Ltd.) from a slurry in which the powder was dispersed in water as a solvent.
Moreover, the specific surface area in this invention means the specific surface area calculated | required by BET (Brunauer-Emmett-Teller) method which is a well-known technique.
The rare earth oxide powder obtained by the present invention has the advantages of both fine particles and giant particles that are large particles that have good fluidity and are easy to handle but have a large specific surface area. Therefore, the rare earth oxide powder of the present invention is suitable for uses such as a three-way catalyst, a gas sensor, an oxygen storage material, and a hydrogen storage alloy because of having such characteristics, and has a special internal structure. Since the internal fine structure can be controlled, it is also suitable as a ceramic raw material.
以下、実施例及び比較例を示し、本発明を具体的に説明するが、本発明は下記の実施例に制限されるものではない。 EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
［実施例１］
酸化イットリウムを硝酸に溶解し、該希土類溶液を純水により希釈し、濃度０．１ｍｏｌ／Ｌの硝酸イットリウム溶液を１Ｌ調製した。この溶液に尿素６０ｇ（関東化学（株）製）とヘキサメチレンテトラミン７０ｇ（関東化学（株）製）を添加し、該溶液を湯浴で室温から９５℃に加熱した。溶液の温度が上昇するのに伴い沈殿が徐々に析出し始めた。溶液が９５℃に達した後、その温度を６０分間保持した。その後、生じた沈殿をブフナー漏斗を用いてろ別した。得られた沈殿を７５℃のオーブンで１２時間乾燥させ、この沈殿物をアルミナ坩堝に入れ、８００℃で大気雰囲気下で３時間焼成した。これにより、１８．１ｇの流動性の良い酸化イットリウム粉末が得られた。この粉末を走査型電子顕微鏡で観察したところ、平均粒子径が６８μｍの凝集のない球状の粒子であり、ＢＥＴ比表面積を測定したところ２９．３ｍ2／ｇであった。図１に得られた酸化イットリウム粉末の走査電子顕微鏡写真を示す。
[Example 1]
Yttrium oxide was dissolved in nitric acid, and the rare earth solution was diluted with pure water to prepare 1 L of a yttrium nitrate solution having a concentration of 0.1 mol / L. To this solution, 60 g of urea (manufactured by Kanto Chemical Co., Inc.) and 70 g of hexamethylenetetramine (manufactured by Kanto Chemical Co., Ltd.) were added, and the solution was heated from room temperature to 95 ° C. in a hot water bath. As the temperature of the solution increased, a precipitate gradually started to precipitate. After the solution reached 95 ° C, the temperature was held for 60 minutes. The resulting precipitate was then filtered off using a Buchner funnel. The obtained precipitate was dried in an oven at 75 ° C. for 12 hours, and this precipitate was put in an alumina crucible and calcined at 800 ° C. in an air atmosphere for 3 hours. As a result, 18.1 g of yttrium oxide powder having good fluidity was obtained. When this powder was observed with a scanning electron microscope, it was a spherical particle having an average particle diameter of 68 μm and no agglomeration. The BET specific surface area was measured and found to be 29.3 m 2 / g. FIG. 1 shows a scanning electron micrograph of the obtained yttrium oxide powder.
また、この酸化イットリウム粉末の流動性を下記方法により測定したところ、安息角をは２７°であり流動性は良好であった。
非常に良好であった。
〔流動性測定法〕
流動性はＪＩＳ Ｒ ９３０１−２−２を参考に内径φ６ｍｍの漏斗を用いて高さ４０ｍｍの位置から粉末を水平に配置した直径φ４０ｍｍのステージ上に落下させ、粉末が形成する円錐とステージの水平面との成す角を安息角として流動性を示す指標とした。なお安息角が小さいほど粉末の流動性が良いことを意味する。流動性の評価基準として下記のように安息角と流動性の関係を評価した。
〔評価基準〕
◎ ３０°未満 流動性非常に良好
○ ３０°以上４０°未満 流動性比較的良好
× ４０°以上 流動性悪い
The fluidity of the yttrium oxide powder was measured by the following method. The repose angle was 27 ° and the fluidity was good.
It was very good.
[Fluidity measurement method]
The flowability is determined by dropping powder onto a stage with a diameter of 40 mm from a position of 40 mm in height using a funnel with an inner diameter of 6 mm with reference to JIS R 9301-2-2, and the horizontal plane of the cone formed by the powder and the stage The angle formed by the angle of repose was used as an index of fluidity. The smaller the angle of repose, the better the flowability of the powder. The relationship between the angle of repose and the fluidity was evaluated as follows as an evaluation standard for fluidity.
〔Evaluation criteria〕
◎ Less than 30 ° Flowability is very good ○ 30 ° or more and less than 40 ° Fluidity is relatively good × 40 ° or more Flowability is poor
［比較例１］
酸化イットリウムを硝酸に溶解し、該溶液を純水を用いて希釈し、濃度０．１ｍｏｌ／Ｌの硝酸イットリウム溶液を１Ｌ調製した。この溶液に尿素９０ｇ（関東化学（株）製）を添加し、該溶液を湯浴で室温から９５℃に加熱した。溶液の温度が上昇するのに伴い沈殿が徐々に析出し始めた。溶液が９５℃に達した後、その温度を６０分間保持した。その後、生じた沈殿をブフナー漏斗を用いてろ別した。得られた沈殿を７５℃のオーブンで１２時間乾燥させ、この沈殿物をアルミナ坩堝に入れ、８００℃で大気雰囲気下で３時間焼成した。こうして２０．３ｇの酸化イットリウム粉末が得られた。この粉末を走査型電子顕微鏡で観察したところ、平均粒子径が１μｍの球状の粒子であり、凝集が部分的に見られた。ＢＥＴ比表面積を測定したところ７．１ｍ2／ｇであった。得られた粉末の安息角を測定したところ３５°であり流動性は比較的良好であった。
[Comparative Example 1]
Yttrium oxide was dissolved in nitric acid, and the solution was diluted with pure water to prepare 1 L of a yttrium nitrate solution having a concentration of 0.1 mol / L. 90 g of urea (manufactured by Kanto Chemical Co., Inc.) was added to this solution, and the solution was heated from room temperature to 95 ° C. in a hot water bath. As the temperature of the solution increased, a precipitate gradually started to precipitate. After the solution reached 95 ° C, the temperature was held for 60 minutes. The resulting precipitate was then filtered off using a Buchner funnel. The obtained precipitate was dried in an oven at 75 ° C. for 12 hours, and this precipitate was put in an alumina crucible and calcined at 800 ° C. in an air atmosphere for 3 hours. In this way, 20.3 g of yttrium oxide powder was obtained. When this powder was observed with a scanning electron microscope, it was spherical particles having an average particle diameter of 1 μm, and aggregation was partially observed. The BET specific surface area was measured and found to be 7.1 m 2 / g. When the angle of repose of the obtained powder was measured, it was 35 ° and the fluidity was relatively good.
［比較例２］
酸化イットリウムを硝酸に溶解し、該溶液を純水を用いて希釈し、濃度０．１ｍｏｌ／Ｌの硝酸イットリウム溶液を１Ｌ調製した。この溶液にヘキサメチレンテトラミン２１０ｇ（関東化学（株）製）を添加し、該溶液を湯浴で室温から９５℃に加熱した。溶液の温度が上昇するのに伴いヘキサメチレンテトラミンの加水分解により溶液のｐＨが上昇し、沈殿が徐々に析出し始めた。溶液が９５℃に達した後、その温度を６０分間保持した。その後、生じた沈殿をブフナー漏斗を用いてろ別した。得られた沈殿を７５℃のオーブンで１２時間乾燥させ、この沈殿物をアルミナ坩堝に入れ、８００℃で大気雰囲気下で３時間焼成した。こうして１９．２ｇの酸化イットリウム粉末が得られた。この粉末を走査型電子顕微鏡で観察したところ、平均粒子径が２μｍの凝集した針状粒子であり、ＢＥＴ比表面積を測定したところ１４．３ｍ2／ｇであった。得られた粉末の安息角を測定したところ４２°であり流動性は良くなかった。
[Comparative Example 2]
Yttrium oxide was dissolved in nitric acid, and the solution was diluted with pure water to prepare 1 L of a yttrium nitrate solution having a concentration of 0.1 mol / L. To this solution, 210 g of hexamethylenetetramine (manufactured by Kanto Chemical Co., Inc.) was added, and the solution was heated from room temperature to 95 ° C. in a hot water bath. As the temperature of the solution increased, the pH of the solution increased due to the hydrolysis of hexamethylenetetramine, and the precipitate began to gradually precipitate. After the solution reached 95 ° C, the temperature was held for 60 minutes. The resulting precipitate was then filtered off using a Buchner funnel. The obtained precipitate was dried in an oven at 75 ° C. for 12 hours, and this precipitate was put in an alumina crucible and calcined at 800 ° C. in an air atmosphere for 3 hours. In this way, 19.2 g of yttrium oxide powder was obtained. When this powder was observed with a scanning electron microscope, it was agglomerated needle-like particles having an average particle diameter of 2 μm, and the BET specific surface area was measured to be 14.3 m 2 / g. When the angle of repose of the obtained powder was measured, it was 42 ° and the fluidity was not good.
［比較例３］
酸化イットリウムを硝酸に溶解し、該溶液を純水を用いて希釈し、濃度０．１ｍｏｌ／Ｌの硝酸イットリウム溶液を１Ｌ調製した。この溶液に尿素２０８ｇ（関東化学（株）製）とヘキサメチレンテトラミン０．９ｇ（関東化学（株）製）を添加し、該溶液を湯浴で室温から９５℃に加熱した。溶液の温度が上昇するのに伴いヘキサメチレンテトラミン及び尿素の加水分解により溶液のｐＨが上昇し、沈殿が徐々に析出し始めた。溶液が９５℃に達した後、その温度を６０分間保持した。その後、生じた沈殿をブフナー漏斗を用いてろ別した。得られた沈殿を７５℃のオーブンで１２時間乾燥させ、この沈殿物をアルミナ坩堝に入れ、８００℃で大気雰囲気下で３時間焼成した。こうして２０．３ｇの酸化イットリウム粉末が得られた。この粉末を走査型電子顕微鏡で観察したところ、粒子径が１〜３０μｍの範囲の球状粒子と針状粒子の凝集体であり、流動性が悪く、ＢＥＴ比表面積を測定したところ１２．２ｍ2／ｇであった。得られた粉末の安息角を測定したところ４５°であり流動性は良くなかった。
[Comparative Example 3]
Yttrium oxide was dissolved in nitric acid, and the solution was diluted with pure water to prepare 1 L of a yttrium nitrate solution having a concentration of 0.1 mol / L. To this solution, 208 g of urea (manufactured by Kanto Chemical Co., Inc.) and 0.9 g of hexamethylenetetramine (manufactured by Kanto Chemical Co., Ltd.) were added, and the solution was heated from room temperature to 95 ° C. in a hot water bath. As the temperature of the solution increased, the pH of the solution increased due to the hydrolysis of hexamethylenetetramine and urea, and the precipitate began to gradually precipitate. After the solution reached 95 ° C, the temperature was held for 60 minutes. The resulting precipitate was then filtered off using a Buchner funnel. The obtained precipitate was dried in an oven at 75 ° C. for 12 hours, and this precipitate was put in an alumina crucible and calcined at 800 ° C. in an air atmosphere for 3 hours. In this way, 20.3 g of yttrium oxide powder was obtained. When this powder was observed with a scanning electron microscope, it was an agglomerate of spherical particles and needle-like particles having a particle diameter in the range of 1 to 30 μm, poor fluidity, and a BET specific surface area of 12.2 m 2 / g. When the angle of repose of the obtained powder was measured, it was 45 ° and the fluidity was not good.
［比較例４］
酸化イットリウムを硝酸に溶解し、該溶液を純水を用いて希釈し、濃度０．１ｍｏｌ／Ｌの硝酸イットリウム溶液を１Ｌ調製した。この溶液に尿素２．１ｇ（関東化学（株）製）とヘキサメチレンテトラミン８９．２ｇ（関東化学（株）製）を添加し、該溶液を湯浴で室温から９５℃に加熱した。溶液の温度が上昇するのに伴いヘキサメチレンテトラミン及び尿素の加水分解により溶液のｐＨが上昇し、沈殿が徐々に析出し始めた。溶液が９５℃に達した後、その温度を６０分間保持した。その後、生じた沈殿をブフナー漏斗を用いてろ別した。得られた沈殿を７５℃のオーブンで１２時間乾燥させ、この沈殿物をアルミナ坩堝に入れ、８００℃で大気雰囲気下で３時間焼成した。こうして１９．９ｇの酸化イットリウム粉末が得られた。この粉末を走査型電子顕微鏡で観察したところ、粒子径が１〜２０μｍの範囲の針状粒子と球状の凝集体粒子であり、流動性は悪く、ＢＥＴ比表面積を測定したところ１９．１ｍ2／ｇであった。得られた粉末の安息角を測定したところ４４°であり流動性は良くなかった。
[Comparative Example 4]
Yttrium oxide was dissolved in nitric acid, and the solution was diluted with pure water to prepare 1 L of a yttrium nitrate solution having a concentration of 0.1 mol / L. To this solution, 2.1 g of urea (manufactured by Kanto Chemical Co., Inc.) and 89.2 g of hexamethylenetetramine (manufactured by Kanto Chemical Co., Ltd.) were added, and the solution was heated from room temperature to 95 ° C. in a hot water bath. As the temperature of the solution increased, the pH of the solution increased due to the hydrolysis of hexamethylenetetramine and urea, and the precipitate began to gradually precipitate. After the solution reached 95 ° C, the temperature was held for 60 minutes. The resulting precipitate was then filtered off using a Buchner funnel. The obtained precipitate was dried in an oven at 75 ° C. for 12 hours, and this precipitate was put in an alumina crucible and calcined at 800 ° C. in an air atmosphere for 3 hours. In this way, 19.9 g of yttrium oxide powder was obtained. When this powder was observed with a scanning electron microscope, it was a needle-like particle and a spherical aggregate particle having a particle diameter in the range of 1 to 20 μm, the fluidity was poor, and the BET specific surface area was measured to be 19.1 m 2 / g. When the angle of repose of the obtained powder was measured, it was 44 ° and the fluidity was not good.
これらの結果を表１に示した。 These results are shown in Table 1.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013096378A JP5987778B2 (en) | 2013-05-01 | 2013-05-01 | Method for producing rare earth oxide powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013096378A JP5987778B2 (en) | 2013-05-01 | 2013-05-01 | Method for producing rare earth oxide powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2014218383A JP2014218383A (en) | 2014-11-20 |
| JP5987778B2 true JP5987778B2 (en) | 2016-09-07 |
Family
ID=51937216
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2013096378A Active JP5987778B2 (en) | 2013-05-01 | 2013-05-01 | Method for producing rare earth oxide powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5987778B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20200039835A1 (en) * | 2017-02-03 | 2020-02-06 | The South African Nuclear Energy Corporation Soc Limited | Preparation process for rare earth metal fluorides |
| CN113718423B (en) * | 2021-09-08 | 2023-03-14 | 孚韦(内蒙古)安全装备有限公司 | Porous rare earth-doped antibacterial melt-blown material and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0331283B1 (en) * | 1988-02-03 | 1993-04-28 | The Regents Of The University Of Minnesota | High stability porous zirconium oxide spherules |
| JP3803807B2 (en) * | 1995-07-31 | 2006-08-02 | 独立行政法人 日本原子力研究開発機構 | Small liquid supply method |
| JPH10139426A (en) * | 1996-11-13 | 1998-05-26 | Shin Etsu Chem Co Ltd | Yttria spherical particle and its production |
| JP2000188270A (en) * | 1998-12-22 | 2000-07-04 | Hitachi Chem Co Ltd | Cerium oxide abrasive and method of grinding substrate |
-
2013
- 2013-05-01 JP JP2013096378A patent/JP5987778B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2014218383A (en) | 2014-11-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3738454B2 (en) | Composite metal oxide powder and method for producing the same | |
| TWI401211B (en) | Indium oxide powder and method for producing same | |
| JP5520210B2 (en) | Air electrode material powder for solid oxide fuel cell and method for producing the same | |
| Zhou et al. | Investigation on the preparation and properties of monodispersed Al2O3ZrO2 nanopowder via Co-precipitation method | |
| CN110035976B (en) | Zinc oxide powder for use in zinc oxide sintered body having high strength and low thermal conductivity | |
| Jinqing et al. | Preparation of nanoscaled yttrium oxide by citrate precipitation method | |
| Chandradass et al. | Synthesis and characterization of zirconia-and silica-doped zirconia nanopowders by oxalate processing | |
| JP5987778B2 (en) | Method for producing rare earth oxide powder | |
| JP5729926B2 (en) | Gallium oxide powder | |
| JP2016155727A (en) | Polyhedron-shaped aluminum nitride powder and method for manufacturing the same | |
| JP2004315344A (en) | Method for manufacturing single crystal ceramic particle | |
| JP3878867B2 (en) | Indium hydroxide and oxide | |
| Jeong et al. | Synthesis and characterization of Y 2 O 3 powders by a modified solvothermal process | |
| Cheng et al. | Synthesis of sealed sponge ZnO nanospheres through a novel NH3-evaporation method | |
| CN110550952A (en) | zirconia ceramic powder and preparation method thereof | |
| JP5987779B2 (en) | Method for producing rare earth oxide powder | |
| JP3146578B2 (en) | Manufacturing method of zirconia fine powder | |
| JP7408721B2 (en) | Negative thermal expansion materials and composite materials | |
| Li et al. | 5Y–ZrO2 NPs with high dispersity and excellent sintering performance prepared by a novel sol-gel-flux method in the NaCl system | |
| Pazura et al. | Synthesis of Y О and Y О: Nd monodisperse crystalline nanospheres by homogenous precipitation | |
| JP7410249B2 (en) | Negative thermal expansion material, its manufacturing method and composite material | |
| WO2023181781A1 (en) | Negative thermal expansion material, method for manufacturing same, and composite material | |
| WO2022145323A1 (en) | Method for manufacturing vanadium lithium phosphate | |
| JPH05116945A (en) | Production of fine zirconia powder | |
| JP2004083350A (en) | Method for manufacturing rare earth oxide fine powder having 100 nm or less primary particle size, and rare earth oxide fine powder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20150526 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20160317 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20160412 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20160517 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20160712 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20160725 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5987778 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |