JPH0155201B2 - - Google Patents

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Publication number
JPH0155201B2
JPH0155201B2 JP59109108A JP10910884A JPH0155201B2 JP H0155201 B2 JPH0155201 B2 JP H0155201B2 JP 59109108 A JP59109108 A JP 59109108A JP 10910884 A JP10910884 A JP 10910884A JP H0155201 B2 JPH0155201 B2 JP H0155201B2
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JP
Japan
Prior art keywords
ultrafine
gas
metal powder
flame
particles
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.)
Expired
Application number
JP59109108A
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Japanese (ja)
Other versions
JPS60255602A (en
Inventor
Kazuhide Oota
San Abe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
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Toyota Motor Corp
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Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP59109108A priority Critical patent/JPS60255602A/en
Priority to DE8585101305T priority patent/DE3581293D1/en
Priority to EP85101305A priority patent/EP0151490B1/en
Priority to US06/699,909 priority patent/US4705762A/en
Publication of JPS60255602A publication Critical patent/JPS60255602A/en
Publication of JPH0155201B2 publication Critical patent/JPH0155201B2/ja
Granted legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00Nanotechnology for materials or surface science, e.g. nanocomposites
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J3/00Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
    • B01J3/06Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies
    • B01J3/08Application of shock waves for chemical reactions or for modifying the crystal structure of substances
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00Silicon; Compounds thereof
    • C01B33/113Silicon oxides; Hydrates thereof
    • C01B33/12Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/18Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
    • C01B33/181Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof by a dry process
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    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/0602Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with two or more other elements chosen from metals, silicon or boron
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    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/0612Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with alkaline-earth metals, beryllium or magnesium
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    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/0615Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with transition metals other than titanium, zirconium or hafnium
    • C01B21/0622Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with transition metals other than titanium, zirconium or hafnium with iron, cobalt or nickel
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    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/068Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with silicon
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/072Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with aluminium
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00Nitrogen; Compounds thereof
    • C01B21/06Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/076Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with titanium or zirconium or hafnium
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00Crystal-structural characteristics
    • C01P2002/02Amorphous compounds
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00Particle morphology
    • C01P2004/30Particle morphology extending in three dimensions
    • C01P2004/32Spheres
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00Particle morphology
    • C01P2004/60Particles characterised by their size
    • C01P2004/62Submicrometer sized, i.e. from 0.1-1 micrometer
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2004/60Particles characterised by their size
    • C01P2004/64Nanometer sized, i.e. from 1-100 nanometer
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2006/10Solid density
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    • C01P2006/80Compositional purity

Description

【発明の詳細な説明】 〔技術分野〕 本発明は粉塵爆発を利用した酸化物超微粒子の
製造方法に関する。 〔従来技術〕 粒径1000Å以下のセラミツク超微粒子は、表面
エネルギの寄与が大きく、そのため低温で容易に
焼結したり、触媒活性が増大するという利点を有
しており、かかるセラミツク超微粒子の量産、低
コスト化が望まれている。 かかるセラミツク超微粒子を気相から製造する
方法として、例えば「化学工学」1982年10月刊の
525頁〜529頁の「微粉体材料の製造と表面改質の
技術」に示されている気相化学反応法等が公知で
ある。この気相化学反応法の熱源としてはアー
ク、プラズマ、化学炎等を用いることができる。
この化学炎法には、H2−O2炎やCxHy−O2炎に
よる揮発性金属ハロゲン化物からの酸化物超微粒
子の合成例がある。例えば、光フアイバ用母材と
しての超高純度シリカは次式に示すような反応で
合成されている。 SiCl4(気体)+2H2(気体) +02(気体)→SiO2(超微粒子)+4HCl(気体) 上記反応では、四塩化珪素(SiCl4)と水素
(H2)と酸素(O2)が反応して、二酸化珪素
(SiO2)の超微粒子と塩化水素(HCl)が生成さ
れる。この反応では、四塩化珪素自体が高価なこ
とと四塩化珪素中における珪素の重量比が小さい
ことにより大量生産に向かず、また塩化水素のよ
うな有害な副産物が発生するという問題がある。 そこで、本件出願人は上記問題を解決するた
め、粉塵爆発を利用してセラミツク超微粒子を効
率良く低コストで得る製造方法を提案した(願番
未着:未公知)。このセラミツク超微粒子の製造
方法は、目的とするセラミツク超微粒子の一部を
形成する元素を含んだ反応ガス中で、目的とする
セラミツク超微粒子の他の一部を形成する金属粉
末の粉塵雲を形成し、着火させることにより爆燃
を起こさせてセラミツク超微粒子を合成すること
を特徴としており、反応ガスとして酸素、塩素、
窒素を用いることにより、それぞれ酸化物、塩化
物、窒化物を得ることができた。 ところで、上記出願に係るセラミツク超微粒子
の製造方法においては、実施例において熱源とし
て火花放電を利用した例を示した。この火花放電
を利用する方法は、装置自体は簡単なものになる
ものの、(a)高温部分が小さな領域であるため、粉
塵雲に燃焼が広がらない場合がある、(b)燃焼が瞬
間的で、金属粉末の表面酸化のみで終わる場合が
ある、(c)金属粉末の均一分散が困難である、等の
不十分な点があつた。 このため、粉塵爆発を利用する超微粒子の製造
方法において、更に望ましい熱源が求められてい
る。 〔発明の目的〕 本発明は上記要望に基づきなされたもので、本
発明は、酸化物超微粒子の製造において、熱源を
工夫することにより粉塵爆発を安定的に生じさ
せ、もつて熱効率および量産性の向上を図ること
にある。 〔発明の構成〕 かかる目的は、本発明によれば、次の酸化物超
微粒子の製造方法によつて達成される。 即ち、本発明の酸化物超微粒子の製造方法は、
酸素を含む雰囲気内においてバーナにより化学炎
を形成し、この化学炎中に目的とする酸化物超微
粒子の一部を形成する金属粉末を粉塵雲が形成さ
れる程度の量投入し、爆燃を起こさせて酸化物超
微粒子を合成することを特徴としている。 本発明において得られる酸化物超微粒子として
は、酸化チタン(TiO2)、酸化ジルコニウム
(ZrO2)、酸化アルミニウム(Al2O3)、二酸化珪
素(SiO2)等がある。 本発明において、酸化物超微粒子の一部を形成
する金属としては、珪素、アルミニウム、チタ
ン、ジルコニウム等を用いることができる。 この反応ガスと反応する金属粉末は、酸化物超
微粒子を製造するためには、粒径が400μm以下
であることが望ましく、できるだけ小さい方がよ
り望ましい。また、金属粉末は可能な限り不純物
の少ないものが望ましい。 この金属粉末は反応に際しては粉塵雲と称され
る状態とされる。この粉塵雲は、金属粉末の種類
にもよるが少なくとも濃度が20g/m3以上である
ことが必要であり、通常は500g/m3以上が望ま
しく、1000g/m3以上とすることがより望まし
い。通常は500g/m3以上でないと安定な着火が
得られない。即ち、粉塵雲の濃度は濃い方が望ま
しい。 着火の熱源としては、抵抗加熱、アーク放電、
プラズマフレーム、レーザ、高周波誘導加熱、電
子ビーム等が考えられるが、本発明においては化
学炎を用いることに特徴がある。化学炎として
は、H2−O2炎、CxYz−O2炎等があり、通常バ
ーナを用いて形成する。 化学炎を熱源とした場合、従来技術のところで
述べた火花放電の欠点はなく、またプラズマフレ
ームを利用した場合には、次のような欠点がある
が、化学炎ではこのような欠点が解消される。 (a) 設備のためのイニシヤルコストが大きい。 (b) ガス、電気を大量に消費し、かつ電極も寿命
が数百時間と短いためランニングコストが大き
い。 (c) プラズマの流速が音速を越え非常に速いため
金属粉末の投入方法が難しく、一部はじき出さ
れるため未燃焼のものができる。 (d) 酸化は発熱反応であり連鎖的に生じるため、
本来プラズマのような高温は必要とせず、プラ
ズマの熱量を有効に活用していない。 本発明の反応は、大気圧で行うことができる。
但し、加圧下、減圧下でも行うことができる。 〔発明の作用〕 本発明においては、まず容器中に反応ガスであ
る酸素を含有するガスを充満させ、この反応ガス
中で化学炎を形成する。次いで、この化学炎に金
属粉末を投入し高濃度(500g/m3以上)の粉塵
雲を形成する。すると、化学炎により金属粉末表
面に熱エネルギが与えられ、金属粉末の表面温度
が上昇し、金属粉末表面から金属の蒸気が周囲に
広がる。この金属蒸気が酸素ガスと反応して発火
し火炎を生じる。この火炎により生じた熱は、更
に金属粉末の気化を促進し、生じた金属蒸気と反
応ガスが混合され、連鎖的に発火伝播する。この
とき、金属粉末自体も破裂して飛散し、火炎伝播
を促す。燃焼後に、生成ガスが自然冷却されるこ
とにより、酸化物超微粒子の雲ができる。得られ
た酸化物超微粒子は、通常電気集塵器等により帯
電させて捕集する。 〔発明の効果〕 以上より、本発明によれば、以下の効果を奏す
る。 (イ) 原料の金属粉末蒸気と反応ガスの反応の際生
じる発熱により、他の金属粉末の気化が促進さ
れるので、外部から与える熱エネルギは着火を
生ぜしめるだけのごく僅かでよく、熱効率
(100%以上)が極めてよい。 (ロ) 粉塵爆発の原理を利用しているため、瞬時に
大量の酸化物超微粒子が得られ、量産性が高
い。 (ハ) 熱源として化学炎を用いるため、未燃焼、不
完全燃焼が防止され、完全な酸化物超微粒子が
得られる。 (ニ) 化学炎への金属粉末の投入が容易であり、バ
ーナの火口付近は低温であるため、プラズマの
ように金属粉末が溶けて詰ることがない。 (ホ) 流速がプラズマより遅いため、化学炎を形成
する可燃物質の高温領域で、プラズマより金属
粉末が長く留まることができる。 (ヘ) 製造工程が比較的単純なため自動化が容易で
ある。 〔実施例〕 次に、本発明の実施例を図面を参考にして説明
する。 この実施例は酸化物超微粒子として二酸化珪素
超微粒子を製造した例を示す。 ここで、第1図は本発明の実施例に使用した酸
化物超微粒子製造装置の概要を示す概略構成図で
ある。 図中、1は酸化物超微粒子製造装置の外殻を形
成する密閉容器であり、この密閉容器1内の底部
にはガスバーナ2が取り付けられている。このガ
スバーナ2の先端には石英からなる燃焼筒3が装
着されており、この燃焼筒3内のガスバーナ2の
火口近傍には点火装置4の先端が取り付けられて
いる。 ガスバーナ2の内部は実質的に2重管とされ、
内側の空間部は導入管5の一端と接続されてい
る。この導入管5の途中には、金属粉末を供給す
るホツパ6が設けられ、ホツパ6とガスバーナ2
の間の導入管5にはボールバルブ7が設けられて
いる。このボールバルブ7は制御装置8により開
閉を制御される。この導入管5の他端は金属粉末
のキヤリアガスとしての水素供給源と接続されて
おり、バルブ9によりその供給が制御される。 ガスバーナ2の外側の空間部には、第1のガス
管10と第2のガス管11の一端が開口してお
り、第1のガス管10の他端は酸素供給源と、第
2のガス管11の他端は水素供給源と接続され、
それぞれバルブ12,13を介してガス量が制御
される。 また、第3のガス管14の一端は上記燃焼筒3
の内部に開口しており、他端はアルゴンと酸素の
供給源と接続され、バルブ15によりガス量が制
御される。 燃焼筒3の上方に位置する密閉容器1の上部に
は、排気管16が取り付けられ、この排気管16
の途中には電気集塵器17が取り付けられてい
る。 かかる酸化物超微粒子接続装置を用いて酸化物
超微粒子の製造を行つた。 まず、ホツパ6に原料となる金属粉末を装填す
る。次いで、バルブ15を開き、第3のガス管1
4を介してアルゴンガスと酸素の混合ガスを密閉
容器1内へ導入し、大気と置換させる。このと
き、アルゴンガスと酸素の体積比は4:1とし
た。続いて、バルブ12,13を開き、第1のガ
ス管10から酸素を20/minで、また第2のガ
ス管11から水素を10/minでガスバーナ2に
供給し、点火装置4により着火して酸水素炎から
なる燃焼炎を形成する。次いで、ホツパ6の下部
を開き、制御装置8によりボールバルブ7を0.5
秒間隔で開閉しつつ、バルブ9を開いて1Kg/cm2
のガス圧をかけた水素で金属粉末をガスバーナ2
に供給する。すると、金属粉末はガスバーナ2の
火口から舞い上がつて粉塵雲を形成する。この粉
塵雲は上記燃焼炎18により着火し、爆燃により
大量の酸化物超微粒子が得られる。合成により生
じた酸化物超微粒子の雲19を電気集塵器17に
通すことにより酸化物超微粒子が捕集される。 かかる酸化物超微粒子の製造を、金属粉末の材
料を後掲の第1表に示すように、種々変えて行つ
た。この結果得られた酸化物超微粒子を透過型電
子顕微鏡(TEM)で観察し、粒径、形状、結晶
性を調べた。この結果を第1表に併せ示す。 第1表から明らかなように、本実施例によれ
ば、球形または球状多面体をした粒径5〜100n
mの酸化物超微粒子が得られるのが判る。 また、従来技術のところで述べた放電着火した
ものに比べ、合成率が30%以上向上した。 【表】
DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing ultrafine oxide particles using dust explosion. [Prior art] Ceramic ultrafine particles with a particle size of 1000 Å or less have a large surface energy contribution, and therefore have the advantage of being easily sintered at low temperatures and increasing catalytic activity. , cost reduction is desired. As a method for producing such ultrafine ceramic particles from the gas phase, for example, "Chemical Engineering", October 1982 issue,
The gas phase chemical reaction method shown in "Techniques for producing fine powder materials and surface modification" on pages 525 to 529 is well known. Arc, plasma, chemical flame, etc. can be used as a heat source for this gas phase chemical reaction method.
This chemical flame method includes examples of synthesis of ultrafine oxide particles from volatile metal halides using H2 - O2 flame and CxHy- O2 flame. For example, ultra-high purity silica as a base material for optical fibers is synthesized by the reaction shown in the following formula. SiCl 4 (gas) + 2H 2 (gas) +0 2 (gas) → SiO 2 (ultrafine particles) + 4HCl (gas) In the above reaction, silicon tetrachloride (SiCl 4 ), hydrogen (H 2 ) and oxygen (O 2 ) are The reaction produces ultrafine particles of silicon dioxide (SiO 2 ) and hydrogen chloride (HCl). This reaction has problems in that it is not suitable for mass production because silicon tetrachloride itself is expensive and the weight ratio of silicon in silicon tetrachloride is small, and it also generates harmful by-products such as hydrogen chloride. Therefore, in order to solve the above-mentioned problem, the present applicant has proposed a manufacturing method for efficiently obtaining ultrafine ceramic particles at low cost using dust explosion (application number not received: unknown). This method for producing ultrafine ceramic particles involves generating a dust cloud of metal powder, which forms another part of the ultrafine ceramic particles, in a reaction gas containing an element that forms a part of the ultrafine ceramic particles. It is characterized by forming and igniting it to cause deflagration and synthesize ultrafine ceramic particles, using oxygen, chlorine,
By using nitrogen, we were able to obtain oxides, chlorides, and nitrides, respectively. By the way, in the method for manufacturing ultrafine ceramic particles according to the above application, an example in which spark discharge is used as a heat source is shown in the embodiment. Although this method of using spark discharge makes the device itself simple, (a) the high-temperature area is small, so the combustion may not spread to the dust cloud, and (b) the combustion is instantaneous. (c) It was difficult to uniformly disperse the metal powder. Therefore, a more desirable heat source is required in a method for producing ultrafine particles using dust explosion. [Object of the Invention] The present invention has been made based on the above-mentioned needs, and the present invention aims to stably generate a dust explosion by devising a heat source in the production of ultrafine oxide particles, thereby improving thermal efficiency and mass productivity. The aim is to improve the [Structure of the Invention] According to the present invention, this object is achieved by the following method for producing ultrafine oxide particles. That is, the method for producing ultrafine oxide particles of the present invention includes:
A chemical flame is formed by a burner in an atmosphere containing oxygen, and metal powder that forms part of the target oxide ultrafine particles is injected into the chemical flame in an amount sufficient to form a dust cloud, causing deflagration. It is characterized by the fact that ultrafine oxide particles are synthesized by Examples of ultrafine oxide particles obtained in the present invention include titanium oxide (TiO 2 ), zirconium oxide (ZrO 2 ), aluminum oxide (Al 2 O 3 ), and silicon dioxide (SiO 2 ). In the present invention, silicon, aluminum, titanium, zirconium, etc. can be used as the metal forming a part of the oxide ultrafine particles. In order to produce ultrafine oxide particles, the metal powder that reacts with this reaction gas preferably has a particle size of 400 μm or less, and is more preferably as small as possible. Further, it is desirable that the metal powder contains as few impurities as possible. This metal powder is brought into a state called a dust cloud during the reaction. This dust cloud needs to have a concentration of at least 20 g/m 3 or more, although it depends on the type of metal powder, usually 500 g/m 3 or more is desirable, and more preferably 1000 g/m 3 or more. . Normally, stable ignition cannot be obtained unless it is 500 g/m 3 or more. That is, it is desirable that the dust cloud be denser. Heat sources for ignition include resistance heating, arc discharge,
Possible methods include plasma flame, laser, high-frequency induction heating, and electron beam, but the present invention is characterized by the use of chemical flame. Chemical flames include H2 - O2 flame, CxYz- O2 flame, etc., and are usually formed using a burner. When a chemical flame is used as a heat source, there is no disadvantage of spark discharge mentioned in the section of conventional technology, and when a plasma flame is used, there are the following disadvantages, but with a chemical flame, these disadvantages are eliminated. Ru. (a) The initial cost for equipment is large. (b) Running costs are high because they consume large amounts of gas and electricity, and the electrodes have a short lifespan of several hundred hours. (c) Because the flow velocity of plasma is extremely fast, exceeding the speed of sound, it is difficult to introduce metal powder, and some of it is thrown out, leaving unburned material. (d) Because oxidation is an exothermic reaction and occurs in a chain reaction,
It does not originally require high temperatures like plasma, and does not utilize the heat of plasma effectively. The reactions of the invention can be carried out at atmospheric pressure.
However, it can also be carried out under increased pressure or reduced pressure. [Operation of the Invention] In the present invention, first, a container is filled with a gas containing oxygen as a reactive gas, and a chemical flame is formed in this reactive gas. Metal powder is then introduced into this chemical flame to form a highly concentrated dust cloud (500 g/m 3 or more). Then, thermal energy is applied to the surface of the metal powder by the chemical flame, the surface temperature of the metal powder increases, and metal vapor spreads from the surface of the metal powder to the surrounding area. This metal vapor reacts with oxygen gas and ignites, producing a flame. The heat generated by this flame further promotes vaporization of the metal powder, and the generated metal vapor and reaction gas are mixed, causing a chain reaction of ignition and propagation. At this time, the metal powder itself also ruptures and scatters, promoting flame propagation. After combustion, the resulting gas is naturally cooled, creating a cloud of ultrafine oxide particles. The obtained ultrafine oxide particles are usually charged and collected using an electric precipitator or the like. [Effects of the Invention] As described above, according to the present invention, the following effects are achieved. (b) The heat generated during the reaction between the raw material metal powder vapor and the reaction gas promotes the vaporization of other metal powders, so only a small amount of external heat energy is needed to cause ignition, and thermal efficiency ( 100% or more) is extremely good. (b) Since it uses the principle of dust explosion, a large amount of ultrafine oxide particles can be obtained instantly, making it highly suitable for mass production. (c) Since a chemical flame is used as a heat source, unburned and incomplete combustion is prevented, and perfect ultrafine oxide particles can be obtained. (d) It is easy to introduce metal powder into a chemical flame, and the temperature near the burner's crater is low, so unlike plasma, metal powder does not melt and cause clogging. (e) Because the flow velocity is slower than plasma, metal powder can remain longer than plasma in the high-temperature region of combustible materials that form chemical flames. (F) The manufacturing process is relatively simple and can be easily automated. [Example] Next, an example of the present invention will be described with reference to the drawings. This example shows an example in which ultrafine silicon dioxide particles were produced as ultrafine oxide particles. Here, FIG. 1 is a schematic configuration diagram showing an outline of an oxide ultrafine particle manufacturing apparatus used in an example of the present invention. In the figure, reference numeral 1 denotes a closed container forming the outer shell of the ultrafine oxide particle manufacturing apparatus, and a gas burner 2 is attached to the bottom of the closed container 1. A combustion tube 3 made of quartz is attached to the tip of the gas burner 2, and the tip of an igniter 4 is attached near the mouth of the gas burner 2 inside the combustion tube 3. The inside of the gas burner 2 is essentially a double pipe,
The inner space is connected to one end of the introduction tube 5. A hopper 6 for supplying metal powder is provided in the middle of the introduction pipe 5, and the hopper 6 and gas burner 2
A ball valve 7 is provided in the introduction pipe 5 between the two. The opening and closing of this ball valve 7 is controlled by a control device 8. The other end of the introduction pipe 5 is connected to a hydrogen supply source as a carrier gas for metal powder, and its supply is controlled by a valve 9. One end of a first gas pipe 10 and a second gas pipe 11 are opened in the space outside the gas burner 2, and the other end of the first gas pipe 10 is connected to an oxygen supply source and a second gas pipe. The other end of the pipe 11 is connected to a hydrogen supply source,
The gas amount is controlled via valves 12 and 13, respectively. Further, one end of the third gas pipe 14 is connected to the combustion tube 3.
The other end is connected to an argon and oxygen supply source, and the gas amount is controlled by a valve 15. An exhaust pipe 16 is attached to the upper part of the closed container 1 located above the combustion tube 3.
An electric precipitator 17 is installed in the middle. Ultrafine oxide particles were produced using this ultrafine oxide particle connecting device. First, the hopper 6 is loaded with metal powder as a raw material. Next, open the valve 15 and open the third gas pipe 1.
A mixed gas of argon gas and oxygen is introduced into the closed container 1 through the gas tube 4 to replace the atmosphere. At this time, the volume ratio of argon gas and oxygen was set to 4:1. Subsequently, the valves 12 and 13 were opened, oxygen was supplied from the first gas pipe 10 at a rate of 20/min, and hydrogen was supplied from the second gas pipe 11 at a rate of 10/min to the gas burner 2, and ignited by the ignition device 4. A combustion flame consisting of an oxyhydrogen flame is formed. Next, open the lower part of the hopper 6, and control the ball valve 7 by 0.5
1Kg/cm 2 by opening and closing valve 9 at intervals of seconds.
Gas burner 2 burns metal powder with hydrogen under a gas pressure of
supply to. Then, the metal powder flies up from the crater of the gas burner 2 and forms a dust cloud. This dust cloud is ignited by the combustion flame 18, and a large amount of ultrafine oxide particles are obtained by deflagration. The ultrafine oxide particles are collected by passing the cloud 19 of ultrafine oxide particles produced by the synthesis through the electrostatic precipitator 17 . The production of such ultrafine oxide particles was carried out by changing the material of the metal powder in various ways as shown in Table 1 below. The resulting ultrafine oxide particles were observed using a transmission electron microscope (TEM) to examine particle size, shape, and crystallinity. The results are also shown in Table 1. As is clear from Table 1, according to this example, spherical or spherical polyhedral particles with a diameter of 5 to 100n
It can be seen that ultrafine oxide particles of m are obtained. Additionally, the synthesis rate was improved by more than 30% compared to the one using discharge ignition as described in the conventional technology section. 【table】

【図面の簡単な説明】[Brief explanation of drawings]

第1図は本発明の実施例に使用した酸化物超微
粒子製造装置の概要を示す概略構成図である。 1……密閉容器、2……ガスバーナ、3……燃
焼筒、4……点火装置、5……導入管、6……ホ
ツパ、7……ボールバルブ、8……制御装置、
9,12,13,15……バルブ、10……第1
のガス管、11……第2のガス管、14……第3
のガス管、16……排気管、17……電気集塵
器、18……燃焼炎、19……酸化物超微粒子の
雲。
FIG. 1 is a schematic diagram showing the outline of an oxide ultrafine particle manufacturing apparatus used in an example of the present invention. DESCRIPTION OF SYMBOLS 1... Airtight container, 2... Gas burner, 3... Combustion tube, 4... Ignition device, 5... Introductory pipe, 6... Hopper, 7... Ball valve, 8... Control device,
9, 12, 13, 15... Valve, 10... 1st
gas pipe, 11... second gas pipe, 14... third gas pipe
gas pipe, 16...exhaust pipe, 17...electrostatic precipitator, 18...combustion flame, 19...cloud of ultrafine oxide particles.

Claims (1)

【特許請求の範囲】[Claims] 1 酸素を含む雰囲気内においてバーナにより化
学炎を形成し、この化学炎中に目的とする酸化物
超微粒子の一部を形成する金属粉末を粉塵雲が形
成される程度の量投入し、爆燃を起こさせて酸化
物超微粒子を合成することを特徴とする酸化物超
微粒子の製造方法。
1. A chemical flame is formed using a burner in an atmosphere containing oxygen, and metal powder that forms part of the target oxide ultrafine particles is put into the chemical flame in an amount sufficient to form a dust cloud, and a deflagration is caused. 1. A method for producing ultrafine oxide particles, characterized by synthesizing ultrafine oxide particles.
JP59109108A 1984-02-09 1984-05-29 Preparation of ultrafine particle of oxide Granted JPS60255602A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP59109108A JPS60255602A (en) 1984-05-29 1984-05-29 Preparation of ultrafine particle of oxide
DE8585101305T DE3581293D1 (en) 1984-02-09 1985-02-07 METHOD FOR PRODUCING ULTRAFINE CERAMIC PARTICLES.
EP85101305A EP0151490B1 (en) 1984-02-09 1985-02-07 Process for producing ultra-fine ceramic particles
US06/699,909 US4705762A (en) 1984-02-09 1985-02-08 Process for producing ultra-fine ceramic particles

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59109108A JPS60255602A (en) 1984-05-29 1984-05-29 Preparation of ultrafine particle of oxide

Publications (2)

Publication Number Publication Date
JPS60255602A JPS60255602A (en) 1985-12-17
JPH0155201B2 true JPH0155201B2 (en) 1989-11-22

Family

ID=14501769

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59109108A Granted JPS60255602A (en) 1984-02-09 1984-05-29 Preparation of ultrafine particle of oxide

Country Status (1)

Country Link
JP (1) JPS60255602A (en)

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