JP2000290018A - Iron oxide powder and method for producing the same - Google Patents
Iron oxide powder and method for producing the sameInfo
- Publication number
- JP2000290018A JP2000290018A JP11095767A JP9576799A JP2000290018A JP 2000290018 A JP2000290018 A JP 2000290018A JP 11095767 A JP11095767 A JP 11095767A JP 9576799 A JP9576799 A JP 9576799A JP 2000290018 A JP2000290018 A JP 2000290018A
- Authority
- JP
- Japan
- Prior art keywords
- iron oxide
- powder
- based powder
- silica
- iron
- 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
Links
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims abstract description 136
- 239000000843 powder Substances 0.000 title claims abstract description 61
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000010438 heat treatment Methods 0.000 claims abstract description 22
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 12
- 150000002505 iron Chemical class 0.000 claims abstract description 9
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000002612 dispersion medium Substances 0.000 claims abstract description 4
- 230000000704 physical effect Effects 0.000 claims abstract description 3
- 239000003054 catalyst Substances 0.000 claims description 7
- 239000002244 precipitate Substances 0.000 claims description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 5
- 229910000510 noble metal Inorganic materials 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 claims description 2
- 229910002651 NO3 Inorganic materials 0.000 claims description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 2
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- 238000010304 firing Methods 0.000 claims description 2
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 claims description 2
- 239000011259 mixed solution Substances 0.000 claims 2
- 229910004298 SiO 2 Inorganic materials 0.000 abstract description 18
- 239000002253 acid Substances 0.000 abstract description 8
- 239000007864 aqueous solution Substances 0.000 abstract description 7
- 238000000034 method Methods 0.000 abstract description 6
- 239000010419 fine particle Substances 0.000 abstract description 3
- 239000002994 raw material Substances 0.000 abstract description 3
- 230000003472 neutralizing effect Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 abstract 1
- 229910052760 oxygen Inorganic materials 0.000 description 24
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 23
- 239000001301 oxygen Substances 0.000 description 23
- 230000000052 comparative effect Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 3
- IVORCBKUUYGUOL-UHFFFAOYSA-N 1-ethynyl-2,4-dimethoxybenzene Chemical compound COC1=CC=C(C#C)C(OC)=C1 IVORCBKUUYGUOL-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 238000003917 TEM image Methods 0.000 description 2
- 229910052910 alkali metal silicate Inorganic materials 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000001034 iron oxide pigment Substances 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- -1 sodium or potassium Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 150000003754 zirconium Chemical class 0.000 description 1
Landscapes
- Compounds Of Iron (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
(57)【要約】
【課題】 耐酸性，耐熱性に優れ、しかも、高温下での
熱処理後においても“比表面積，酸化鉄自体の特性”を
保持し得る、新規な多孔質の酸化鉄系粉末およびその製
造方法を提供すること。
【解決手段】 酸化鉄粉末の周囲に５〜２５重量％のシ
リカを非晶質の状態で共存させた酸化鉄系粉末であっ
て、大気中で８００℃，５時間熱処理した後の比表面積
が４５ｍ2／ｇ以上の物性値を有する酸化鉄系粉末。該
粉末は、ＳｉＯ2原料として、特に“水を分散媒とする
シリカゾル”を用い、シリカゾルが分散されている水溶
液中で、水溶性鉄塩を中和することによって、シリカと
酸化鉄とを均一に混合させ、加熱焼成過程で、酸化鉄微
粒子の周囲にＳｉＯ2を皮膜状に析出させて製造する。PROBLEM TO BE SOLVED: To provide a novel porous iron oxide excellent in acid resistance and heat resistance and capable of maintaining "specific surface area and characteristics of iron oxide itself" even after heat treatment at high temperature. To provide a powder and a method for producing the same. SOLUTION: This is an iron oxide-based powder in which 5 to 25% by weight of silica coexists in an amorphous state around the iron oxide powder, and has a specific surface area after heat treatment at 800 ° C. for 5 hours in the air. An iron oxide-based powder having physical properties of 45 m 2 / g or more. The powder is prepared by uniformly using silica “sol using water as a dispersion medium” as a raw material of SiO 2 , and neutralizing a water-soluble iron salt in an aqueous solution in which the silica sol is dispersed, so that silica and iron oxide can be uniformly mixed. And in the heating and baking process, SiO 2 is deposited in the form of a film around the iron oxide fine particles to produce a film.
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、酸化鉄系粉末およ
びその製造方法に関する。特に、本発明は、耐酸性，耐
熱性に優れ、しかも、高温下での熱処理後においても、
比表面積が殆ど変化せず、かつ、酸化鉄自体のもつ特性
(酸素の吸蔵放出特性など)を保持し得る多孔質の酸化鉄
系粉末およびその製造方法に関する。The present invention relates to an iron oxide powder and a method for producing the same. In particular, the present invention is excellent in acid resistance and heat resistance, and even after heat treatment at a high temperature,
The specific surface area hardly changes and the characteristics of iron oxide itself
The present invention relates to a porous iron oxide-based powder capable of maintaining (eg, oxygen storage and release characteristics) and a method for producing the same.
【０００２】[0002]
【従来の技術】酸化鉄粉末は、顔料や触媒担体等として
広く使用されているが、これは、耐酸性，耐熱性などに
劣るという欠点を有している。そこで、酸化鉄粉末を改
質し、耐酸性や耐熱性に優れた安定な酸化鉄粉末を得る
ために、不定形シリカで表面処理を行うことが提案され
ている。2. Description of the Related Art Iron oxide powders are widely used as pigments, catalyst carriers, etc., but have the disadvantage that they are inferior in acid resistance and heat resistance. Therefore, it has been proposed to perform surface treatment with amorphous silica in order to modify the iron oxide powder and obtain a stable iron oxide powder having excellent acid resistance and heat resistance.
【０００３】例えば、特開昭53-34826号公報には、安定
な酸化鉄顔料を得るために「酸化鉄顔料粒子の水性スラ
リ−にジルコニウム塩水溶液を添加し、該粒子表面に水
酸化ジルコニウムを沈積させた後、シリカゾルを添加混
合し、水酸化ジルコニウムを沈積した顔料粒子表面に微
細な不定形シリカを沈積させること。」が示されてい
る。また、特開昭60-172351号公報には、耐熱性に優れ
た鉄・クロム系の一酸化炭素転化触媒を得るために「Fe
2O3：Cr2O3が1：0.01〜0.1の重量比で含有する組成物
に、SiO2として表して0.01〜10重量％含有させるこ
と。」が示されている。For example, JP-A-53-34826 discloses that in order to obtain a stable iron oxide pigment, an aqueous solution of zirconium salt is added to an aqueous slurry of iron oxide pigment particles, and zirconium hydroxide is added to the surface of the particles. After the deposition, a silica sol is added and mixed to deposit fine amorphous silica on the surface of the pigment particles on which zirconium hydroxide is deposited. " Also, Japanese Patent Application Laid-Open No. 60-172351 discloses an iron-chromium-based carbon monoxide conversion catalyst having excellent heat resistance, `` Fe
A composition containing 2 O 3 : Cr 2 O 3 in a weight ratio of 1: 0.01 to 0.1, expressed as SiO 2 , in an amount of 0.01 to 10% by weight. "It is shown.
【０００４】[0004]
【発明が解決しようとする課題】前記従来技術によれ
ば、酸化鉄粉末に不定形シリカを含有させることで、耐
酸性，耐熱性に優れたものが得られるが、高温下で熱処
理すると、比表面積が変化し、多孔質のものが得られな
いという欠点を有している。また、酸化鉄粉末それ自体
は、酸素の吸蔵放出能特性を有しているが、これも上記
と同様、高温下で熱処理すると、該特性が著しく低下す
るという問題があった。According to the above-mentioned prior art, an iron oxide powder containing amorphous silica can provide a material having excellent acid resistance and heat resistance. There is a disadvantage that the surface area changes and a porous material cannot be obtained. Further, the iron oxide powder itself has oxygen storage / release capability characteristics. However, similarly to the above, there is a problem that when heat treatment is performed at a high temperature, the characteristics are significantly reduced.
【０００５】本発明は、上記欠点，問題点を解消する酸
化鉄系粉末およびその製造方法を提供することを目的と
する。すなわち、本発明は、 ・第一に、耐酸性，耐熱性に優れ、しかも、高温下での
熱処理後においても、比表面積が殆ど変化しない特性を
有する新規な多孔質の酸化鉄系粉末およびその製造方法
を提供することを目的とし、 ・第二に、同じく高温下での熱処理後においても、酸化
鉄自体のもつ特性(酸素の吸蔵放出特性など)を保持し得
る新規な多孔質の酸化鉄系粉末およびその製造方法を提
供することを目的とする。An object of the present invention is to provide an iron oxide-based powder which solves the above-mentioned drawbacks and problems, and a method for producing the same. That is, the present invention firstly provides a novel porous iron oxide-based powder having excellent properties in acid resistance and heat resistance, and having a characteristic that the specific surface area hardly changes even after heat treatment at a high temperature; Secondly, a novel porous iron oxide that can retain the properties of iron oxide itself (such as oxygen storage / release properties) even after heat treatment at a high temperature. It is an object to provide a system powder and a method for producing the same.
【０００６】[0006]
【課題を解決するための手段】本発明に係る酸化鉄系粉
末は、「酸化鉄粉末の周囲に５〜２５重量％のシリカを
非晶質の状態で共存させた酸化鉄系粉末であって、大気
中で８００℃，５時間熱処理した後の比表面積が４５ｍ
2／ｇ以上の物性値を有すること」(請求項１)、を特徴
(発明を特定する事項)とし、これにより、前記第一の目
的および第ニの目的とする酸化鉄系粉末を提供すること
ができる。The iron oxide powder according to the present invention is an iron oxide powder in which 5 to 25% by weight of silica coexists in an amorphous state around the iron oxide powder. The specific surface area after heat treatment at 800 ° C for 5 hours in air is 45m
2 / g or more ”(Claim 1).
(Matters specifying the invention), whereby the first and second objects of the iron oxide-based powder can be provided.
【０００７】一方、本発明に係る方法は、上記酸化鉄系
粉末を製造する方法であって、「(1) 水を分散媒とする
シリカゾルを準備する工程と、(2) 前記シリカゾルに水
溶性鉄塩を添加混合する工程と、(3) 前記混合溶液のｐ
Ｈを調整することにより、沈殿を生成させる工程と、
(4) 前記沈殿物を焼成する工程と、を含むこと」(請求
項４)を特徴(発明を特定する事項)とし、これにより、
前記第一，第ニの目的を達成することができる。On the other hand, a method according to the present invention is a method for producing the above iron oxide-based powder, comprising: (1) preparing a silica sol using water as a dispersion medium; and (2) water-soluble silica sol. (3) adding and mixing an iron salt;
Adjusting H to produce a precipitate;
(4) a step of firing the precipitate ”(claim 4).
The first and second objects can be achieved.
【０００８】[0008]
【発明の実施の形態】以下、本発明の実施の形態を挙
げ、本発明について詳細に説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention.
【０００９】本発明に係る酸化鉄系粉末は、前記したと
おり、「酸化鉄粉末の周囲に５〜２５重量％のシリカを
非晶質の状態で共存させた酸化鉄系粉末であって、大気
中で８００℃，５時間熱処理した後の比表面積が４５ｍ
2／ｇ以上の物性値を有すること」を特徴とし、これに
より、耐酸性，耐熱性に優れ、しかも、高比表面積を高
温まで保持し、また、酸化鉄自体のもつ特性(酸素の吸
蔵放出特性など)を高温まで保持し得る新規な多孔質の
酸化鉄系粉末を提供することができる。The iron oxide-based powder according to the present invention is, as described above, an iron oxide-based powder in which 5 to 25% by weight of silica coexists in an amorphous state around the iron oxide powder. Specific surface area after heat treatment at 800 ° C for 5 hours in water
2 / g or more of physical properties ”, which is excellent in acid resistance and heat resistance, keeps high specific surface area up to high temperature, and has the characteristics (storage and release of oxygen) of iron oxide itself. Characteristic) can be provided to a high temperature.
【００１０】そして、該粉末の実施の形態として、その
粒子径が５〜１５ｎｍであることを特徴とし、このよう
に、シリカの被覆された微構造からなるにもかかわら
ず、容易に酸素の吸蔵放出を行うことができるため、酸
素の吸蔵放出作用を利用する目的に対して好適な新規な
多孔質の酸化鉄系粉末を提供することができる。An embodiment of the powder is characterized in that its particle size is 5 to 15 nm. Thus, despite its fine structure covered with silica, it easily absorbs oxygen. Since release can be performed, a novel porous iron oxide-based powder suitable for the purpose of utilizing the occlusion and release action of oxygen can be provided.
【００１１】シリカの含有量が５重量％未満では、“高
温下での熱処理後において、比表面積が殆ど変化しない
酸化鉄系粉末”が得られ難く、また、“高温下での熱処
理後において、酸化鉄自体のもつ特性を保持し得る酸化
鉄系粉末”が得られ難いので好ましくない。一方、シリ
カの含有量が２５重量％を超えた場合、高温下での熱処
理後においても、比表面積がより大きくなるけれども、
この場合、酸化鉄自体のもつ特性が極端に低下し、酸化
鉄自体の触媒作用などの性質を利用する目的には適さな
いので、好ましくない。When the content of silica is less than 5% by weight, it is difficult to obtain “an iron oxide powder whose specific surface area hardly changes after heat treatment at a high temperature”. It is not preferable because it is difficult to obtain an "iron oxide-based powder" capable of maintaining the characteristics of iron oxide itself. On the other hand, when the content of silica exceeds 25% by weight, although the specific surface area becomes larger even after the heat treatment at a high temperature,
In this case, the properties of the iron oxide itself are extremely deteriorated and are not suitable for the purpose of utilizing the properties such as the catalytic action of the iron oxide itself, which is not preferable.
【００１２】本発明に係る酸化鉄系粉末は、その用途と
して、特に限定するものではないが、貴金属触媒担持用
担体として好適である。その理由は、本発明に係る酸化
鉄系粉末は、前記したとおり、高比表面積を高温まで保
持する多孔質酸化鉄系粉末であるから、これを貴金属触
媒担持用鉄系担体として使用すると、高温下において
も、内部から活性な酸素を放出し、炭化水素などによる
貴金属触媒の被毒を防止するという優れた作用効果が生
じるからである。The use of the iron oxide-based powder according to the present invention is not particularly limited, but is suitable as a carrier for supporting a noble metal catalyst. The reason is that, as described above, the iron oxide-based powder according to the present invention is a porous iron oxide-based powder that maintains a high specific surface area up to a high temperature. This is because, even underneath, an excellent effect of releasing active oxygen from the inside and preventing the noble metal catalyst from being poisoned by hydrocarbons or the like is produced.
【００１３】次に、本発明に係る酸化鉄系粉末の製造方
法の実施形態について説明する。本発明は、ＳｉＯ2原
料として、特に“水を分散媒とするシリカゾル”を用い
ることを特徴とする。そして、シリカゾルが分散されて
いる水溶液中で、水溶性鉄塩を中和することによって、
シリカと酸化鉄とが均一に混合され、加熱の過程で酸化
鉄微粒子の周囲にＳｉＯ2を皮膜状に析出させることが
でき、これによって、前記した優れた特性を有する多孔
質の酸化鉄系粉末を得ることができる。Next, an embodiment of the method for producing an iron oxide-based powder according to the present invention will be described. The present invention is characterized in that “a silica sol using water as a dispersion medium” is used as a SiO 2 raw material. Then, by neutralizing the water-soluble iron salt in the aqueous solution in which the silica sol is dispersed,
Silica and iron oxide are uniformly mixed, and SiO 2 can be deposited in the form of a film around the iron oxide fine particles in the course of heating, whereby the porous iron oxide powder having the above-described excellent properties is obtained. Can be obtained.
【００１４】本発明において、ＳｉＯ2源としては、ア
ルカリ金属ケイ酸塩を用いることはできない。この場合
のアルカリ性物質は、ナトリウム，カリウムなどのアル
カリ金属であり、強アルカリ性であるために、鉄塩水溶
液を混合する際、混合と同時に沈殿が生成して、酸化鉄
とＳｉＯ2の均一な混合状態が達成されない。従って、
アルカリ金属ケイ酸塩を原料とした場合、耐熱性の優れ
た酸化鉄系粉末は得られず、また、アルカリ金属塩は、
中和後も加熱によって除去できないために洗浄工程が必
要となるため、製造コストの面からも好ましくない。In the present invention, an alkali metal silicate cannot be used as the SiO 2 source. In this case, the alkaline substance is an alkali metal such as sodium or potassium, and since it is strongly alkaline, when an iron salt aqueous solution is mixed, a precipitate is formed at the same time as mixing, so that the iron oxide and SiO 2 are uniformly mixed. The state is not achieved. Therefore,
When an alkali metal silicate is used as a raw material, an iron oxide-based powder having excellent heat resistance cannot be obtained.
Since the washing step is required because it cannot be removed by heating even after the neutralization, it is not preferable from the viewpoint of manufacturing cost.
【００１５】本発明において、前記水溶性鉄塩として
は、鉄の酢酸塩，クエン酸塩，硝酸塩から選ばれる１種
の水溶性鉄塩であることが好ましく、また、シリカゾル
に水溶性鉄塩を混合し、沈殿を生成させる際のｐＨ調整
手段としては、アンモニアによりｐＨを６〜１０の範囲
に保持することが好ましい。これにより、前記した優れ
た特性を有する多孔質の酸化鉄系粉末を得ることができ
る。In the present invention, the water-soluble iron salt is preferably one kind of water-soluble iron salt selected from iron acetate, citrate and nitrate. As a pH adjusting means for mixing and forming a precipitate, it is preferable to maintain the pH in the range of 6 to 10 with ammonia. As a result, a porous iron oxide-based powder having the above-described excellent characteristics can be obtained.
【００１６】[0016]
【実施例】次に、本発明の実施例を比較例と共に挙げ、
本発明を具体的に説明する。Next, examples of the present invention will be described together with comparative examples.
The present invention will be specifically described.
【００１７】（実施例１〜５，比較例１〜５）硝酸鉄９
水和物と固形分２０ｗｔ％のシリカゾルとを、表１のよ
うに秤量し、５００ｇの水に溶解して混合水溶液とし
た。一方、２５％アンモニア水を表１のように秤量し、
５００ｇの水で希釈した。(Examples 1 to 5, Comparative Examples 1 to 5) Iron nitrate 9
A hydrate and a silica sol having a solid content of 20 wt% were weighed as shown in Table 1, and dissolved in 500 g of water to obtain a mixed aqueous solution. On the other hand, 25% ammonia water was weighed as shown in Table 1,
Diluted with 500 g of water.
【００１８】次に、上記混合水溶液と上記希釈したアン
モニア水とを、プロペラ攪拌機を用いて攪拌しながら混
合し、沈澱を形成させた。続いて、この沈澱を含む水溶
液を１５０℃で１０時間乾燥し、さらに４００℃で５時
間焼成して酸化鉄系(Fe2O3−SiO2系)粉末を得た。な
お、ＳｉＯ2含有率“5wt％，10wt％，15wt％，20wt％，
25wt％”の各粉末が実施例１〜５であり、ＳｉＯ2含有
率“0wt％，30wt％，50wt％，70wt％，100wt％”の各粉
末が比較例１〜５である(→表１参照)。Next, the mixed aqueous solution and the diluted aqueous ammonia were mixed with stirring using a propeller stirrer to form a precipitate. Subsequently, the aqueous solution containing the precipitate was dried at 150 ° C. for 10 hours and further calcined at 400 ° C. for 5 hours to obtain an iron oxide-based (Fe 2 O 3 —SiO 2 -based) powder. Incidentally, SiO 2 content of "5wt%, 10wt%, 15wt %, 20wt%,
25 wt% "each powder is the embodiment 1 to 5, SiO 2 content of" 0wt%, 30wt%, 50wt %, 70wt%, each powder of 100 wt% "are comparative examples 1 to 5 (→ Table 1 reference).
【００１９】得られた各粉末(４００℃焼成品)の比表面
積を「ＢＥＴ，１点法」により測定し、その結果を表１
に示し、これを図１にグラフ化した。また、得られた各
粉末(４００℃焼成品)を更に“６００℃，８００℃”で
５時間焼成し、各粉末の比表面積を同じく「ＢＥＴ，１
点法」により測定し、その結果を表１に示し、これを図
１にグラフ化した。The specific surface area of each of the obtained powders (calcined at 400 ° C.) was measured by the “BET, one-point method”.
This is shown in FIG. Further, each of the obtained powders (calcined at 400 ° C.) was further calcined at “600 ° C., 800 ° C.” for 5 hours, and the specific surface area of each powder was similarly changed to “BET, 1”.
The results were shown in Table 1, which was graphed in FIG.
【００２０】さらに、上記“４００℃焼成品”の各粉末
に対して、次の「酸素吸蔵放出能」の測定を行い、その
結果を同じく表１に示し、これを図２にグラフ化した。 ・「酸素吸蔵放出能(Ｏ2ｍｇ／ｇ)の測定」 熱重量分析装置を用い、試料を“４００℃，８００℃”
に加熱した状態で、５％Ｈ2／Ｎ2バランスのガスと２０
％Ｏ2／Ｎ2バランスのガスとを、１分間ずつ交互に流通
させ、重量変化を測定する方法で酸素の吸蔵放出能(Ｏ2
ｍｇ／ｇ)を測定した。（なお、表１中の“低下率”
は、各試料において、「８００℃，酸素吸蔵放出能」が
「４００℃，酸素吸蔵放出能」の場合に比してどの程度
低下したかを“百分率(％)”で算出した値である。）Further, the following “oxygen storage / release capacity” was measured for each powder of the “calcined at 400 ° C.”, and the results are also shown in Table 1, which is graphed in FIG.・ “Measurement of oxygen storage / release capacity (O 2 mg / g)”
5% H 2 / N 2 gas and 20%
% O 2 / N 2 balance gas is alternately flowed for 1 minute, and the oxygen storage / release capacity (O 2
mg / g). (Note that the “decrease rate” in Table 1)
Is a value calculated by “percentage (%)” to show how much “800 ° C., oxygen storage / release capability” is reduced as compared with “400 ° C., oxygen storage / release capability” in each sample. )
【００２１】[0021]
【表１】 [Table 1]
【００２２】表１の“比表面積(ｍ2／ｇ)”の欄および
図１からみて、本発明の“ＳｉＯ2含有率：５〜２５ｗ
ｔ％”の範囲内である実施例１〜実施例５の酸化鉄系粉
末は、８００℃焼成品で、いずれも４５ｍ2／ｇ以上で
あり、特に、ＳｉＯ2含有率が１０ｗｔ％以上の実施例
２〜実施例５では、１００ｍ2／ｇ以上の比表面積を維
持することがわかった。なお、８００℃焼成品で、Ｓｉ
Ｏ2含有率が３０ｗｔ％以上の比較例２〜比較例５で
は、さらに比表面積が大きくなることを示しているが、
これは、酸化鉄との相互作用を持たない遊離のＳｉＯ2
が増加するためである。そして、次に記載するとおり、
比表面積が数値の上で大きくても、酸化鉄自体の触媒作
用などの性質を利用する目的には適さないことがわかっ
た。From the column of "specific surface area (m 2 / g)" in Table 1 and FIG. 1, the "SiO 2 content of the present invention: 5 to 25 w
The iron oxide-based powders of Examples 1 to 5 in the range of “t%” were calcined at 800 ° C., all of which had a content of 45 m 2 / g or more, and in particular, had a SiO 2 content of 10 wt% or more. In Examples 2 to 5, it was found that the specific surface area was maintained at 100 m 2 / g or more.
Comparative Examples 2 to 5 having an O 2 content of 30 wt% or more show that the specific surface area is further increased.
This is because free SiO 2 has no interaction with iron oxide.
Is to increase. And, as described below,
It has been found that even if the specific surface area is large numerically, it is not suitable for the purpose of utilizing properties such as the catalytic action of iron oxide itself.
【００２３】一方、表１の“酸素吸蔵放出能”の欄およ
び図２からみて、Ｆｅ2Ｏ3のみからなる粉末(比較例１)
では、８００℃熱処理により酸素吸蔵放出能が大きく低
下したが(低下率：８２．４％)、実施例１〜実施例５で
は、８００℃で熱処理してもその低下率が小さく(低下
率：２２％以下)、かつ酸素吸蔵放出能の値も“２０(Ｏ
2ｍｇ／ｇ)前後”と高い値であることがわかった。Ｓｉ
Ｏ2含有率が３０ｗｔ％以上の比較例２〜比較例５で
は、４００℃，８００℃のいずれの場合も、酸素吸蔵放
出能が少なく、かつ８００℃熱処理により酸素吸蔵放出
能が大きく低下し(低下率：３０％以上)、酸化鉄自体の
触媒作用などの性質を利用する目的には適さないことが
わかった。On the other hand, from the column of “Oxygen storage / release capacity” in Table 1 and FIG. 2, the powder consisting of Fe 2 O 3 alone (Comparative Example 1)
In Example 1, the oxygen storage / release capacity was significantly reduced by the heat treatment at 800 ° C. (decrease rate: 82.4%), but in Examples 1 to 5, the decrease rate was small even after heat treatment at 800 ° C. (decrease rate: 22% or less), and the value of oxygen storage / release capacity is also “20 (O
About 2 mg / g).
In Comparative Examples 2 to 5 in which the O 2 content is 30% by weight or more, the oxygen storage / release capacity is small at both 400 ° C. and 800 ° C., and the oxygen storage / release capacity is significantly reduced by the heat treatment at 800 ° C. (Decrease rate: 30% or more), which is not suitable for the purpose of utilizing properties such as the catalytic action of iron oxide itself.
【００２４】更に具体的に説明すると、 ８００℃で５
時間焼成した後、ＳｉＯ2を含まない酸化鉄粉末は、比
表面積が１ｍ2／ｇまで低下するため、熱処理後の酸素
の吸蔵放出速度が小さくなってしまうが、本発明のＦｅ
2Ｏ3−ＳｉＯ2系酸化物粉末は、４５ｍ2／ｇ以上の比表
面積を維持しているため、高い酸素吸蔵放出速度を保っ
ていることがわかる。More specifically, at 800 ° C., 5
After calcination for an hour, the iron oxide powder containing no SiO 2 has a specific surface area reduced to 1 m 2 / g, so that the oxygen storage / release rate after the heat treatment is reduced.
Since the 2 O 3 —SiO 2 -based oxide powder maintains a specific surface area of 45 m 2 / g or more, it can be seen that a high oxygen storage / release rate is maintained.
【００２５】図３に、実施例２で得られた酸化鉄系(Fe2
O3-10wt％SiO2)粉末のＴＥＭ像を示す。該図から、約１
０ｎｍの酸化鉄微粒子の周囲に非晶質のシリカが被覆さ
れた状態の微構造が観察される。このことから、シリカ
の被覆層が酸化鉄の耐熱性を高めていることがわかる。FIG. 3 shows the iron oxide (Fe 2) obtained in Example 2.
3 shows a TEM image of O 3 -10 wt% SiO 2 ) powder. From the figure, about 1
A fine structure in which amorphous silica is coated around the 0 nm iron oxide fine particles is observed. This indicates that the silica coating layer increases the heat resistance of the iron oxide.
【００２６】このように、本発明に係る酸化鉄系粉末
は、シリカの被覆された微構造を取っているにもかかわ
らず、容易に酸素の吸蔵放出を行うことができるため、
酸素の吸蔵放出作用を利用する目的に好適である。As described above, the iron oxide-based powder according to the present invention can easily occlude and release oxygen despite having a microstructure coated with silica.
It is suitable for the purpose of utilizing the oxygen storage / release action.
【００２７】[0027]
【発明の効果】本発明は、以上詳記したとおり、耐酸
性，耐熱性に優れ、しかも、高温下での熱処理後におい
ても比表面積が殆ど変化しない特性を有する多孔質の酸
化鉄系粉末を提供することができる。特に、本発明に係
る酸化鉄系粉末は、大気中で８００℃，５時間熱処理し
た後の比表面積が４５ｍ2／ｇ以上という高比表面積を
有するものであり、このように、高比表面積を高温まで
保持する多孔質酸化鉄系粉末であるから、これを貴金属
触媒担持用鉄系担体として使用すると、高温下において
も、内部から活性な酸素を放出し、炭化水素などによる
貴金属触媒の被毒を防止するという優れた効果が生じ
る。As described in detail above, the present invention provides a porous iron oxide-based powder having excellent acid resistance and heat resistance, and having a characteristic that the specific surface area hardly changes even after heat treatment at a high temperature. Can be provided. In particular, the iron oxide-based powder according to the present invention has a high specific surface area of 45 m 2 / g or more after heat treatment at 800 ° C. for 5 hours in the air. Since it is a porous iron oxide-based powder that holds up to high temperatures, if it is used as an iron-based carrier for supporting a noble metal catalyst, it can release active oxygen from the inside even at high temperatures and poison the noble metal catalyst with hydrocarbons. An excellent effect of preventing the occurrence of an image is generated.
【図１】ＳｉＯ2添加量(0〜100wt％)および熱処理温度
変化(400℃，600℃，800℃)と比表面積との関係(表１)
をグラフ化した図である。FIG. 1 shows the relationship between the added amount of SiO 2 (0 to 100% by weight), the heat treatment temperature change (400 ° C., 600 ° C., 800 ° C.) and the specific surface area (Table 1).
FIG.
【図２】ＳｉＯ2添加量(0〜100wt％)および熱処理温度
変化(400℃，800℃)と酸素吸蔵放出能との関係(表１)を
グラフ化した図である。FIG. 2 is a graph showing the relationship (Table 1) between the added amount of SiO 2 (0 to 100% by weight), the change in the heat treatment temperature (400 ° C., 800 ° C.), and the oxygen storage / release ability.
【図３】実施例２で得られた酸化鉄系(Fe2O3-10wt％SiO
2)粉末のＴＥＭ像である。FIG. 3 shows an iron oxide (Fe 2 O 3 -10 wt% SiO) obtained in Example 2.
2 ) A TEM image of the powder.
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年４月２日（１９９９．４．２）[Submission date] April 2, 1999 (1999.4.2)
【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３[Correction target item name] Figure 3
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【図３】 FIG. 3
───────────────────────────────────────────────────── 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） 4G002 AA12 AB05 AD04 AE05 4G066 AA22B AA27B AA52D AA53A AB23A BA09 BA20 BA26 CA37 FA05 FA21 FA33 FA34 GA01 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Nobuo Kamiya, No. 41, 41, Chuchu, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture F-term in Toyota Central Research Laboratory Co., Ltd. 4G002 AA12 AB05 AD04 AE05 4G066 AA22B AA27B AA52D AA53A AB23A BA09 BA20 BA26 CA37 FA05 FA21 FA33 FA34 GA01
Claims (6)
リカを非晶質の状態で共存させた酸化鉄系粉末であっ
て、大気中で８００℃，５時間熱処理した後の比表面積
が４５ｍ2／ｇ以上の物性値を有することを特徴とする
酸化鉄系粉末。1. An iron oxide powder in which 5 to 25% by weight of silica coexists in an amorphous state around iron oxide powder, and has a specific surface area after heat treatment at 800 ° C. for 5 hours in the air. Has a physical property value of 45 m 2 / g or more.
であることを特徴とする請求項１に記載の酸化鉄系粉
末。2. The iron oxide powder has a particle size of 5 to 15 nm.
The iron oxide-based powder according to claim 1, wherein
系粉末を貴金属触媒担持用担体として使用することを特
徴とする請求項１または請求項２に記載の酸化鉄系粉
末。3. The iron oxide-based powder according to claim 1, wherein the iron oxide-based powder according to claim 1 or 2 is used as a carrier for supporting a noble metal catalyst.
する工程と、(2) 前記シリカゾルに水溶性鉄塩を添加混
合する工程と、(3) 前記混合溶液のｐＨを調整すること
により、沈殿を生成させる工程と、(4) 前記沈殿物を焼
成する工程と、を含むことを特徴とする酸化鉄系粉末の
製造方法。(4) a step of preparing a silica sol using water as a dispersion medium; (2) a step of adding and mixing a water-soluble iron salt to the silica sol; and (3) adjusting the pH of the mixed solution. , And (4) a step of firing the precipitate, thereby producing an iron oxide-based powder.
酸塩，硝酸塩から選ばれる１種の水溶性鉄塩であること
を特徴とする請求項４に記載の酸化鉄系粉末の製造方
法。5. The iron oxide-based powder according to claim 4, wherein the water-soluble iron salt is one kind of water-soluble iron salt selected from iron acetate, citrate and nitrate. Production method.
調整手段として、アンモニアによりｐＨを６〜１０の範
囲に保持することを特徴とする請求項４に記載の酸化鉄
系粉末の製造方法。6. The pH of the mixed solution in the step (3)
The method for producing an iron oxide-based powder according to claim 4, wherein the pH is maintained in the range of 6 to 10 with ammonia as the adjusting means.
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|---|---|---|---|
| JP11095767A JP2000290018A (en) | 1999-04-02 | 1999-04-02 | Iron oxide powder and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11095767A JP2000290018A (en) | 1999-04-02 | 1999-04-02 | Iron oxide powder and method for producing the same |
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| Publication Number | Publication Date |
|---|---|
| JP2000290018A true JP2000290018A (en) | 2000-10-17 |
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ID=14146649
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007530397A (en) * | 2003-07-16 | 2007-11-01 | ザ ユニヴァーシティー オブ リーディング | Composite nanoparticles |
| JP2008063200A (en) * | 2006-09-08 | 2008-03-21 | Univ Of Tokyo | Ε iron oxide powder with good dispersibility |
| JP2008100871A (en) * | 2006-10-19 | 2008-05-01 | Univ Of Tokyo | ε Iron oxide production method |
| JP6092492B1 (en) * | 2015-10-05 | 2017-03-08 | エム・テクニック株式会社 | Composition for laminated coating film comprising iron oxide particles coated with silicon oxide |
| JP2017218570A (en) * | 2015-10-05 | 2017-12-14 | エム・テクニック株式会社 | Silicon oxide-coated iron oxide composition for coating containing iron oxide particles coated with silicon oxide |
| CN108940213A (en) * | 2018-08-08 | 2018-12-07 | 武汉谱信环保科技有限公司 | Magnetic Nano material and preparation method thereof for Magnetic solid phases extraction |
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1999
- 1999-04-02 JP JP11095767A patent/JP2000290018A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007530397A (en) * | 2003-07-16 | 2007-11-01 | ザ ユニヴァーシティー オブ リーディング | Composite nanoparticles |
| JP2008063200A (en) * | 2006-09-08 | 2008-03-21 | Univ Of Tokyo | Ε iron oxide powder with good dispersibility |
| JP2008100871A (en) * | 2006-10-19 | 2008-05-01 | Univ Of Tokyo | ε Iron oxide production method |
| JP6092492B1 (en) * | 2015-10-05 | 2017-03-08 | エム・テクニック株式会社 | Composition for laminated coating film comprising iron oxide particles coated with silicon oxide |
| JP2017218570A (en) * | 2015-10-05 | 2017-12-14 | エム・テクニック株式会社 | Silicon oxide-coated iron oxide composition for coating containing iron oxide particles coated with silicon oxide |
| JP2017218374A (en) * | 2015-10-05 | 2017-12-14 | エム・テクニック株式会社 | Silicon oxide-coated iron oxide composition for coating containing iron oxide particles coated with silicon oxide |
| JP2017218571A (en) * | 2015-10-05 | 2017-12-14 | エム・テクニック株式会社 | Composition for laminated coating film containing iron oxide particles coated with silicon oxide |
| JP2017218568A (en) * | 2015-10-05 | 2017-12-14 | エム・テクニック株式会社 | Silicon oxide-coated iron oxide composition for coating containing iron oxide particles coated with silicon oxide |
| CN108940213A (en) * | 2018-08-08 | 2018-12-07 | 武汉谱信环保科技有限公司 | Magnetic Nano material and preparation method thereof for Magnetic solid phases extraction |
| CN108940213B (en) * | 2018-08-08 | 2021-03-12 | 武汉谱信环保科技有限公司 | Magnetic nano material for magnetic solid phase extraction and preparation method thereof |
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