JP3639279B2

JP3639279B2 - Method and apparatus for synthesizing / refining or spheroidizing powder by thermal plasma

Info

Publication number: JP3639279B2
Application number: JP2003016769A
Authority: JP
Inventors: 好明井上; 章寺島; 誠二横田; 修井戸原
Original assignee: Neturen Co Ltd
Current assignee: Neturen Co Ltd
Priority date: 2003-01-24
Filing date: 2003-01-24
Publication date: 2005-04-20
Anticipated expiration: 2023-01-24
Also published as: JP2004225135A

Description

【０００１】
【発明の属する技術分野】
本発明は、熱プラズマにより高融点の金属又は金属化合物の純度の高い粉末を得るための合成／精製や、焼結加工性のよい粒度の揃った球状粉末を得るための球状化方法および装置に関するものである。
【０００２】
【従来の技術】
従来の熱プラズマによる粉末の精製装置は、図３に示すように原料ホッパー１５から原料粉末をプラズマフレーム１中に供給して溶融し合成されて、溶融と反応ガスにより精製され、精製された粉末４が反応塔３１内に落下して回収容器３３に収集されるようになっている。あるいは熱プラズマによる粉末の球状化装置の場合には、プラズマフレーム１中に供給された原料粉末が熱プラズマにより溶融球状化して、この球状粉末が反応塔３１内に落下して回収容器３３に収集されるようになっている（例えば特許文献１、２、３及び４）。
【０００３】
【特許文献１】
特開平１１−２６９５１１号公報
【特許文献２】
特開平５−９０７５号公報
【特許文献３】
実開平１−６９６３１号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、従来の熱プラズマによる粉末の精製装置では、図３に示すように微粒粉の粉末５が反応塔上部内壁に付着して、この微粒粉５が剥離して落下し、他の粒子とともに回収容器３３に回収される。この微粒粉５中には蒸気圧の低い不純物などが多く、純度の高い粉末４に混じるために高純度の粉末が得られ難かった。なお、ここでいう微粒粉には超微粒粉を含むものである。
【０００５】
また、従来の熱プラズマによる粉末の球状化装置では、前記同様に微粒粉の粉末５が反応塔上部内壁に付着して剥離し、この微粒粉が回収容器に回収される球状粉末４に混じるために成形性の良い粒度の揃った粉末を得るためには分級に手間を要した。
【０００６】
そこで、本発明は、プラズマによる粉末の合成／精製装置において、不純物を含む微粒粉を別個に収集して純度の高い粉末が得られる合成／精製方法と装置、及び微粒粉や粒度の異なる粉末を分別して収集して粒度の揃った焼結加工性のよい球状粉末が得られる球状化方法と装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、本発明の熱プラズマによる粉末の合成／精製方法と装置は、原料粉末をプラズマフレームにより加熱溶融して粉末を合成／精製し、該合成／精製粉末を反応塔底部の回収容器に回収する粉末の合成／精製方法において、該反応塔内壁に微粒粉収集手段を設け、該微粒粉収集手段により反応塔内に浮遊し内壁に付着する不純物を含む微粒粉を収集し、不純物の少ない残部粉末粒子を落下させて前記回収容器に回収することにより、純度の高い製品粉末を得ることを特徴とするものである。
【０００８】
すなわち、本発明者らは前記したように、従来の精製装置では不純物を含む微粒粉が反応塔内壁に集中して付着することに着目し、反応塔内壁に微粒粉収集手段を設けて、これにより反応塔内に浮遊し内壁に付着する超微粒粉を別に収集し、不純物を含まない球状粒子だけを落下させて回収することにより純度の高い製品粉末を得ようとするものである。
【０００９】
また、本発明の熱プラズマによる粉末の球状化方法と装置は、原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に回収する粉末の球状化方法において、該反応塔内壁に微粒粉収集手段を設けて、該微粒粉収集手段により反応塔内に浮遊し内壁に付着する微粒粉を収集し、微粒粉が減少した残部球状粒子を落下させて前記回収容器に回収することにより、微粒粉の混入が少ない粒度の揃った球状粒子を得ることを特徴とするものである。ここでいう微粒粉は超微粒粉を含めたものをいい、以下の説明においても同様である。
【００１０】
すなわち、本発明者らは前記したように、従来の精製装置では粒度の異なる微粒粉が反応塔内壁に集中して付着することに着目し、反応塔内壁に微粒粉収集手段を設けて、これにより反応塔内に浮遊し内壁に付着する微粒粉を別に収集し、微粒粉の混在の少ない成形性の良い均一粒度の球状粉末を得るものである。
【００１１】
また、本発明の熱プラズマによる粉末の球状化方法と装置は、原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に収集する粉末の球状化方法において、該反応塔内壁の上部側に微粒粉収集手段を設け、該内壁の下部側に中粒粉収集手段を設け、前記微粒粉収集手段により反応塔内上部に浮遊し内壁に付着する微粒粉を収集し、前記中粒粉収集手段により反応塔内下部に浮遊する中粒粉を収集し、残部大粒の球状粒子を落下させて前記回収容器に回収することにより、球状粒子を微粒粉と中粒粉と大粒粉とに分別して得ることを特徴とするものである。
【００１２】
すなわち、本発明の熱プラズマによる粉末の球状化方法と装置は、粒度の小さい微粒粉末が反応塔上部内壁に集中し、やや粒度の大きい中粒粉末が反応塔中部、下部に集中することに着目し、反応塔上部の微粒粉収集手段により上部に浮遊し内壁に付着する微粒粉を収集し、下部の中粒粉収集手段により反応塔下部に浮遊する中粒粉を収集し、残りの落下する大粒粉を反応塔底部の回収容器に回収することにより、各粒度ごとに揃った粒度の球状粉を得るものである。
【００１３】
また、前記微粒粉収集手段と中粒粉収集手段のそれぞれまたは一方を２以上備えることにより、さらに粒度を分別して回収することも可能である。
【００１４】
ここで微粒粉、中粒粉、大粒粉というのは、絶対的大きさではなく比較した相対的な大きさをいい、前述のように微粒粉には超微粒粉といわれるものも含み、材料（比重）などにより異なるが、一般的にいえば微粒粉は１０μｍ以下、中粒粉は１０〜３０μｍ、大粒粉は３０μｍ以上位の粒度である。通常回収容器に回収する大粒粉を製品粒粉とするが、微粒粉、中粒粉も用途により使用できる。
【００１５】
前記の精製または球状化装置において、前記微粒粉収集手段と中粒粉収集手段は、反応塔内壁内周に設けられた受け皿と該受け皿に集まる微粒粉を吸引する吸引手段とを備えることが望ましい。
【００１６】
すなわち、反応塔内壁内周に受け皿を設けると内壁に集中して付着する不純物を含む微粒粉末や、粒度の小さい球状粉末がこの受け皿に溜まるのでこれを吸引手段によって吸引することにより簡易に上記目的を達することができる。
【００１７】
【発明の実施の形態】
［実施形態１］
以下、本発明を図示の実施形態について具体的に説明する。図１は本発明実施形態１の球状粉末の精製装置の断面図である。また、図３は従来の球状粉末の精製装置の断面図である。
【００１８】
まず図３に基づき従来の精製装置の全体の構成について説明する。従来の精製装置の主体はプラズマトーチ１１、原料ホッパー１５、反応塔３１及び回収容器３３により構成されている。
【００１９】
プラズマトーチ１１において、高周波誘導コイル１３に通電するとプラズマフレーム１が発生し、石英管１２にＡｒ，Ｈ₂などのガスを供給する。原料粉は原料ホッパー１５から原料供給管１６を介してプラズマフレーム１中に供給される。Ａｒ，Ｈ₂などのガスの導入手段は簡略化のため図示を省略した。
【００２０】
反応塔３１は円筒箱型をなし、円筒部３２の上蓋３４にプラズマトーチ１１が搭載されている。円筒部３２の下部は開口されて回収容器３３に接続されている。反応塔３１内のガスは、円筒部３２の側面の排気口３５に接続されたサイクロン３６、フィルタ３７を通して排気されるようになっている。
【００２１】
上記構成の従来の精製装置の動作について以下に説明する。まず、プラズマトーチ１１の高周波誘導コイル１３に高周波電力を投入し、Ａｒなどのガスを流入するとプラズマフレーム１が石英管１２の下部側から噴出する。
【００２２】
プラズマフレーム１中に原料ホッパー１５から原料供給管１６を介して原料粉末を供給すると、プラズマフレームにより溶融されて球状化した製品粉末４が反応塔３１内で冷却されて落下し回収容器３３に回収される。
【００２３】
この際に、微粒粉５と中粒粉６の一部は排気口３５からサイクロン３６、フィルタ３７に排気され、中粒粉６はサイクロン３６で分離され、微粒粉５はフィルタ３７で分離される。しかし、発生する多くの微粒粉は図３に示すように反応塔上部内壁に集中して上部内壁に付着する。そして、この付着して溜った微粒粉が剥離して落下し回収容器３３に混入する。発明者らはこの微粒粉に蒸気圧の低い不純物などが多く含まれる傾向があることを見出だし、この落下した微粒粉が回収容器３３に回収される製品粉末に混入するために製品粉末の純度が低下することを見出だした。
【００２４】
そこで、図１に示す本発明の精製装置は、微粒粉の混入を低減するよう構成されたものである。プラズマトーチ、反応塔などの構成は図３の従来装置とほぼ同一であるあが、図に示すように反応塔３１の円筒部３２の内壁に受け皿２１と微粒粉を吸引する吸引箱２５などで構成する吸引手段を有する微粒粉収集手段２０が設けられている点で異なる。受け皿２１は円筒部３２の内壁との間隔が上部で開いたテーパ円筒リング２２が底部２２ａで円筒部３２の内壁内周に装着された形状をなしている。受け皿２１に対応する円筒部３２の外周に吸引箱２５が設けられ、受け皿２１と吸引箱２５の間の円筒部３２の円周に亘って多数の吸引孔２３が貫通されている。そして吸引箱２５の吸引口２６が吸引管２７を介してフィルター３８に導通されている。
【００２５】
以下、本発明の精製装置の動作について説明する。プラズマトーチ１１のフレーム１に投入された原料粉末は高温で溶融されて精製され、反応塔３１内に落下する。この際に微粒粉は反応塔３１の上部に浮遊する。そしてこの微粒粉は図に示すように反応塔内壁に付着し、これが剥離して下部に落下する。
【００２６】
本発明の精製装置には、反応塔内壁内周に受け皿２１が設けられているので、反応塔内壁に付着して落下する微粒粉は受け皿２１で受けられ、吸引孔２３から吸引口２６を介して吸引されてフィルター３８に捕集される。
【００２７】
なお、製品粉末より粒度の小さい中粒粉の粉末は排気口３５から吸引され、サイクロン３６、フィルター３７に捕集される。そのために、回収容器３３に回収される製品粉末には微粒粉をほとんど含まない球状粉が得られる。これにより、回収容器３３に回収される製品粉末は、不純物の混入が少なく純度の高い大粒粉の製品粉末が得られる。なお、前述したようにここでいう微粒粉、中粒粉、大粒粉は比較した相対的な粒度をいい、一般的には微粒粉は１０μｍ以下、中粒粉は１０〜３０μｍ、大粒粉は３０μｍ以上位である。
【００２８】
［実施形態２］
次に本発明の粉末の球状化装置について説明する。実施形態２の球状化装置も実施形態１の精製装置と全く同一の装置を使用するので、前記図１に基づいて説明する。
【００２９】
プラズマトーチ１１のフレーム２に投入された原料粉末は高温で溶融されて球状になり反応塔３１内に落下して球状粉末として回収容器３３に回収される。この際に粒度の小さい微粒粉は反応塔上部に浮遊し図に示すように反応塔上部内壁に付着し、剥離して下部に落下する。そのために前記図３の従来の装置では、回収容器に回収される製品粉末には微粒粉が混在する。そのため焼結成形性の良い粒度の球状粉末だけを得るには分級を要するが、微粒であるために分級が困難である。
【００３０】
本発明の精製装置には、内壁内周に受け皿２１が設けられているので、反応塔内壁に付着した微粒粉は受け皿２１に受けられ、吸引孔２３から吸引口２６を介して吸引され、フィルター３８に捕集される。そして、中粒粉は下部の排気口３５から吸引され、サイクロン３６、フィルター３７に捕集される。
【００３１】
これにより、微粒粉、中粒粉、大粒粉（製品粉末）と分級して収集される。そのために、回収容器３３に回収される製品粉末には微粒粉、中粒粉をほとんど含まない焼結成形性の良い粒度の球状粉末だけが分級しないで得られる。なお、ここでいう微粒粉、中粒粉、大粒粉も前述した相対的な粒度をいうものである。
【００３２】
［実施形態３］
図２は本実施形態３の球状化装置の断面図である。上記実施形態２の球状化装置においても微粒粉、中粒粉、大粒の製品粒度品と分級して収集できるが、実施形態３ではさらに積極的に前記受け皿を反応塔下部の排気口にも設けたものである。
【００３３】
図２に基づいて説明すると、実施形態３の球状化装置では、実施形態２の反応塔上部の微粒粉収集手段２０の他に下部に同じ形状の中粒粉収集手段２０´が設けられている。すなわち、実施形態２の上部受け皿２１の他に下部受け皿２１´が設けられ、下部受け皿２１´も上部受け皿２１と同じ形状のテーパ円筒リング２２´が円筒部３２の内壁内周に装着されている。そして上部受け皿２１と同様に吸引孔２３´と吸引箱２５´が設けられ吸気口２６´を介してサイクロン３６、フィルター３７に導通される。
【００３４】
前記実施形態２の中粒粉は下部受け皿２１´によりさらに積極的に収集されるので、回収容器３３に回収される球状粉末はさらに製品粒度以外の粒度の粉末が排除され、均一粒度の製品粉末が得られる。
【００３５】
なお、実施形態３では中粒粉収集手段２０´を実施形態２の下部の排気口３５と共用したが、中粒粉収集手段２０´は排気口３５と別個に設けてもよい。
【００３６】
【実施例】
［実施例１］
実施例１は、Ｗ粉末の精製について、図１の本発明の精製装置と図３の従来の装置とを用いて精練効果を比較した。図４〜６に原料と得られた粉末の顕微鏡写真を示す。図４は原料粉、図５と６は従来の装置と本発明の装置のそれぞれ回収容器に回収された球状粉末を示す。図４に示す破砕形状の原料粉は、図５、図６ともに綺麗に球状化されている。しかし、図５の従来装置による球状粉末は表面に微粒粉が付着しているのに対し、図６の本発明装置による球状粉末は表面にはこのような微粒粉の付着が認められず、微粒粉が微粒粉収集手段により分離されて回収容器には大粒粉のみが回収されたことが判る。
【００３７】
上記の図５の従来装置による球状粉末と図６の本発明装置による球状粉末について不純物を分析した結果を表１に示す。表１から、従来装置、本発明装置ともに原料粉からは不純物は大幅に減少して精練効果が認められる。しかし、本発明装置は従来装置に比し全不純物が共に各段に減少し、本発明装置による精練効果の著しい向上が認められる。
【００３８】
【表１】

【００３９】
［実施例２］
実施例２は、実施例１と同様にしてＭｏ粉末の精製について、本発明の精製装置と従来装置とを用いて精練効果を比較した。図７〜９に粉末の顕微鏡写真を示す。図７は原料粉、図８と９は従来の装置と本発明の装置のそれぞれ回収容器に回収された球状粉末を示す。図７に示す原料粉に対し、図８の従来装置による回収球状粉末は表面に多量の微粒粉が付着して凝集した形状を示し、球状形が認めにくい。これに対し、図９の本発明装置による回収球状粉末は表面に微粒粉の付着がなく綺麗に球状化されている。すなわち本発明装置によれば、微粒粉が分離されて回収容器には大粒粉のみが回収されたことが判る。
【００４０】
実施例１と同様に上記の図８の従来装置による球状粉末と図９の本発明装置による球状粉末について不純物を分析した結果を表２に示す。表２から、従来装置では微粒粉が分離されないので回収粉末の不純物は原料粉からほとんど低減せず、あまり精練効果が認められないことが判る。これに対し本発明装置では微粒粉が分離されるので、不純物が原料粉からほぼ半分以下に減少しており十分な精練効果が認められる。このように、本発明装置は従来装置に比し精練効果の著しい向上が認められる。
【００４１】
【表２】

【００４２】
［実施例３］
実施例３は、Ａｌ₂Ｏ₃粉末について、実施例１、２と同様の図１の本発明の球状化装置と図３の従来の装置とを用いて球状化試験を行った。表３にその試験結果を示す。まず表の見方について説明する。回収容器、サイクロンの欄は従来方法、本発明方法ともに、それぞれ回収容器３３、サイクロン３６に回収された粉末、フィルタの欄は従来方法はフィルタ３７に回収された粉末、本発明方法はフィルタ３７、３８に回収された粉末を示す。粒度別比率は各粒径ごとの粒度分布をＷｔ％で示し合計１００％である。
【００４３】
【表３】

【００４４】
部位別回収率は前述の回収容器、サイクロン、フィルタに回収された粉末の回収比率を示す。粒度別回収効率は各部位で回収された粉末量に対する回収容器では大粒粉、サイクロンでは中粒粉、フィルタでは微粒粉の比率を示す。
【００４５】
表３から、従来方法に対して本発明方法は、回収容器においては中粒粉や微粒粉の混入が減少し大粒粉の回収率が８９％から９５％に向上していることが判る。また、サイクロンにおいては微粒粉の混入が減少し中粒粉の回収率が９３％から９６％に向上していることが判る。
【００４６】
［実施例４］
実施例４は、ＳｉＯ₂粉末について、実施例３と同様に図１の本発明の球状化装置と図３の従来の装置とを用いて球状化試験を行った。表４にその試験結果を示す。表の見方は表３と同様である。
【００４７】
【表４】

【００４８】
表４から、従来方法に対して本発明方法は、実施例３と同様に回収容器においては大粒粉の回収率が８２％から９３％に向上し、サイクロンにおいては中粒粉の回収率が６６％から７７％に向上していることが判る。
【００４９】
上述の実施例３、４に示すように本発明方法によれば、従来方法より回収容器とサイクロンにおいて粒度の異なる粉末の混入が少なく分級がより良く行われるので、回収容器の製品粉末のみでなく、用途によりサイクロンで回収した微粒粉の混入の少ない中粒粉を選択使用することもできる。
【００５０】
以上述べたように、本発明の実施形態の熱プラズマによる粉末の合成／精製方法と装置によれば、反応塔内壁に微粒粉収集手段を設けて、これにより内壁周辺に浮遊する微粒粉を収集し、不純物を含まない球状粒子だけを回収容器に落下させるので高純度の粉末を得ることができる。
【００５１】
また、本発明の熱プラズマによる粉末の球状化方法と装置によれば、反応塔内壁に微粒粉収集手段を設けて、反応塔内に浮遊し内壁に付着する微粒粉を収集して残部球状粒子だけを回収容器に回収するので、微粒粉の混入が少ない成形性の良い粒度の揃った球状粒子を得ることができる。
【００５２】
また、本発明の熱プラズマによる粉末の球状化方法と装置は、反応塔上部と下部に微粒粉収集手段と中粒粉収集手段を設けて、上部の微粒粉収集手段により上部内壁周辺に浮遊する微粒粉を収集し、下部の中粒粉収集手段により反応塔下部内壁周辺に浮遊する中粒粉を収集し、残りの落下する大粒粉を反応塔底部の回収容器に回収することにより、一層各粒度ごとに揃った粒度の球状粉を得ることができる。
【００５３】
上記の微粒粉収集手段と中粒粉収集手段は、反応塔上下部内壁に集中する不純物を含む微粒粉末や、粒度の小さい球状粉末を受ける受け皿とこの受け皿に集まった微粒粉を吸引する吸引手段とを備えるので、上記目的を簡易に達することができる。
【００５４】
【発明の効果】
以上説明したように、本発明の熱プラズマによる粉末の合成／精製方法と装置では、従来装置より不純物の混入の少ない純度の高い粉末が得られるので、合成粉末の性能が向上し新しい用途が開ける。また、本発明の熱プラズマによる粉末の球状化方法と装置では、微粒粉を含まない焼結加工性などのよい均一な所定粒度の球状粉末が得られるので焼結品などの品質が向上する。
【図面の簡単な説明】
【図１】本発明実施形態１の精製装置の断面図
【図２】本発明実施形態２の球状化装置の断面図
【図３】従来の精製／球状化装置の断面図
【図４】本発明実施例１の原料粉末の顕微鏡写真
【図５】本発明実施例１の従来装置による精製粉末の顕微鏡写真
【図６】本発明実施例１の本発明装置による精製粉末の顕微鏡写真
【図７】本発明実施例２の原料粉末の顕微鏡写真
【図８】本発明実施例２の従来装置による精製粉末の顕微鏡写真
【図９】本発明実施例２の本発明装置による精製粉末の顕微鏡写真
【符号の説明】
１プラズマフレーム、３原料粉末、４製品粉末（大粒粉）、５微粒粉、６中粒粉、１１プラズマトーチ、１２石英管、１３高周波誘導コイル、１５原料ホッパー、１６原料供給管、２０微粒粉収集手段、２０´ 中粒粉収集手段、２１、２１´ 受け皿、２２テーパ円筒リング、２３吸引孔、２５吸引箱、２６吸引口、２７吸引管、３１反応塔、３２円筒部、３３回収容器、３４上蓋、３５排気口、３６サイクロン、３７フィルタ、３８フィルタ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthesis / purification for obtaining a powder having a high melting point metal or metal compound by thermal plasma, and a spheronization method and apparatus for obtaining a spherical powder having a good particle size with good sintering processability. Is.
[0002]
[Prior art]
As shown in FIG. 3, the conventional apparatus for purifying powder by thermal plasma supplies raw material powder from the raw material hopper 15 into the plasma flame 1 and melts and synthesizes it. 4 falls into the reaction tower 31 and is collected in the collection container 33. Alternatively, in the case of a powder spheroidizing apparatus using thermal plasma, the raw material powder supplied into the plasma flame 1 is melted and spheroidized by thermal plasma, and the spherical powder falls into the reaction tower 31 and is collected in the recovery container 33. (For example, Patent Documents 1, 2, 3, and 4).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-269511 [Patent Document 2]
Japanese Patent Laid-Open No. 5-9075 [Patent Document 3]
Japanese Utility Model Publication No. 1-69631
[Problems to be solved by the invention]
However, in the conventional apparatus for purifying powder by thermal plasma, as shown in FIG. 3, fine powder 5 adheres to the inner wall of the upper part of the reaction tower, and this fine powder 5 is peeled off and collected together with other particles. It is collected in the container 33. The fine powder 5 has many impurities with low vapor pressure and is mixed with the high-purity powder 4, so that it is difficult to obtain a high-purity powder. The fine powder referred to here includes ultra fine powder.
[0005]
Further, in the conventional powder spheroidizing device using thermal plasma, the fine powder 5 adheres to and peels off from the upper inner wall of the reaction tower as described above, and this fine powder is mixed with the spherical powder 4 collected in the collection container. In addition, in order to obtain a powder having a good moldability and a uniform particle size, it took time and effort to classify.
[0006]
Therefore, the present invention provides a synthesis / purification method and apparatus for separately collecting fine powder containing impurities to obtain a high-purity powder in a powder synthesis / purification apparatus using plasma, and fine powder and powder having different particle sizes. It is an object of the present invention to provide a spheroidizing method and apparatus capable of obtaining a spherical powder which is separated and collected and has a uniform particle size and good sintering workability.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the method and apparatus for synthesizing / purifying powder by thermal plasma according to the present invention comprises synthesizing / purifying powder by heating and melting the raw material powder with a plasma flame, and then synthesizing / purifying the synthesized / purified powder at the bottom of the reaction tower. In the method for synthesizing / refining the powder recovered in the recovery container, fine powder collecting means is provided on the inner wall of the reaction tower, and fine powder containing impurities adhering to the inner wall floating in the reaction tower is collected by the fine powder collecting means. The remaining powder particles with few impurities are dropped and collected in the collection container to obtain a product powder with high purity.
[0008]
That is, as described above, the present inventors pay attention to the fact that fine particles containing impurities concentrate and adhere to the inner wall of the reaction tower in the conventional purification apparatus, and provide the fine particle collecting means on the inner wall of the reaction tower. The ultrafine powder floating in the reaction tower and adhering to the inner wall is separately collected, and only the spherical particles not containing impurities are dropped and collected to obtain a high-purity product powder.
[0009]
In addition, the method and apparatus for spheroidizing powder by thermal plasma according to the present invention is a method for spheroidizing powder by heating a raw material powder by a plasma flame to form a molten spheroid, and collecting the spherical powder in a recovery container at the bottom of the reaction tower. A fine powder collecting means is provided on the inner wall of the reaction tower, the fine powder floating in the reaction tower and adhering to the inner wall is collected by the fine powder collecting means, and the remaining spherical particles in which the fine powder is reduced are dropped to collect the recovery container. It is characterized by obtaining spherical particles having a uniform particle size with little mixing of fine powder. The fine powder referred to here includes super fine powder, and the same applies to the following description.
[0010]
That is, as described above, the present inventors pay attention to the fact that fine particles having different particle sizes are concentrated and adhered to the inner wall of the reaction tower in the conventional refining apparatus, and the fine particle collecting means is provided on the inner wall of the reaction tower. Thus, the fine particles floating in the reaction tower and adhering to the inner wall are separately collected to obtain a spherical powder having a uniform particle size with good formability with little mixture of fine particles.
[0011]
Further, the method and apparatus for spheroidizing powder by thermal plasma of the present invention is a method for spheroidizing powder in which raw material powder is heated and spheroidized by a plasma flame, and the spherical powder is collected in a recovery container at the bottom of the reaction tower. A fine powder collecting means is provided on the upper side of the inner wall of the reaction tower, a medium powder collecting means is provided on the lower side of the inner wall, and the fine powder that floats on the upper part of the reaction tower and adheres to the inner wall is collected by the fine powder collecting means. Then, by collecting the medium-sized powder floating in the lower part of the reaction tower by the medium-sized powder collecting means, dropping the remaining large-sized spherical particles and collecting them in the collection container, the spherical particles are made into fine powder and medium-sized powder. It is characterized in that it is obtained by separating it into large grains.
[0012]
That is, in the method and apparatus for spheroidizing powder by thermal plasma of the present invention, attention is paid to the fact that fine powder with small particle size concentrates on the inner wall of the upper part of the reaction tower, and medium powder with slightly larger particle size concentrates in the middle and lower part of the reaction tower. Then, the fine powder floating on the upper part and adhering to the inner wall is collected by the fine powder collecting means at the upper part of the reaction tower, and the middle fine powder floating on the lower part of the reaction tower is collected by the lower medium powder collecting means, and the remaining drops By collecting large particles in a recovery container at the bottom of the reaction tower, spherical powder having a uniform particle size is obtained for each particle size.
[0013]
In addition, by providing two or more of each or one of the fine particle collecting means and the medium particle collecting means, it is possible to further separate and collect the particle size.
[0014]
Here, fine powder, medium powder, and large powder mean relative sizes rather than absolute sizes. As mentioned above, fine powder includes what is called ultrafine powder, Generally speaking, fine particles have a particle size of 10 μm or less, medium particles 10 to 30 μm, and large particles 30 μm or more. Usually, large particles collected in a collection container are used as product particles, but fine particles and medium particles can be used depending on the application.
[0015]
In the refining or spheroidizing apparatus, it is desirable that the fine powder collecting means and the medium powder collecting means comprise a tray provided on the inner periphery of the reaction tower inner wall and a suction means for sucking the fine powder collected in the tray. .
[0016]
That is, when a tray is provided on the inner wall of the reaction tower, fine powder containing impurities that concentrate on the inner wall and spherical powder with a small particle size are collected in the tray. Can be reached.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
Hereinafter, the present invention will be specifically described with reference to the illustrated embodiments. FIG. 1 is a cross-sectional view of a spherical powder refining device according to Embodiment 1 of the present invention. FIG. 3 is a sectional view of a conventional refiner for spherical powder.
[0018]
First, the overall configuration of a conventional purification apparatus will be described with reference to FIG. The main body of the conventional purification apparatus is composed of a plasma torch 11, a raw material hopper 15, a reaction tower 31, and a recovery container 33.
[0019]
When the high frequency induction coil 13 is energized in the plasma torch 11, the plasma flame 1 is generated, and gases such as Ar and H ₂ are supplied to the quartz tube 12. The raw material powder is supplied into the plasma flame 1 from the raw material hopper 15 through the raw material supply pipe 16. A gas introducing means such as Ar and H ₂ is not shown for simplicity.
[0020]
The reaction tower 31 has a cylindrical box shape, and the plasma torch 11 is mounted on the upper lid 34 of the cylindrical portion 32. The lower part of the cylindrical part 32 is opened and connected to the collection container 33. The gas in the reaction tower 31 is exhausted through a cyclone 36 and a filter 37 connected to the exhaust port 35 on the side surface of the cylindrical portion 32.
[0021]
The operation of the conventional purification apparatus having the above configuration will be described below. First, when high frequency power is supplied to the high frequency induction coil 13 of the plasma torch 11 and a gas such as Ar is introduced, the plasma frame 1 is ejected from the lower side of the quartz tube 12.
[0022]
When the raw material powder is supplied into the plasma flame 1 from the raw material hopper 15 through the raw material supply pipe 16, the product powder 4 melted and spheroidized by the plasma flame is cooled and dropped in the reaction tower 31 and recovered in the recovery container 33. Is done.
[0023]
At this time, a part of the fine powder 5 and the medium powder 6 are exhausted from the exhaust port 35 to the cyclone 36 and the filter 37, the medium powder 6 is separated by the cyclone 36, and the fine powder 5 is separated by the filter 37. . However, as shown in FIG. 3, many fine particles generated concentrate on the upper inner wall of the reaction tower and adhere to the upper inner wall. Then, the fine powder accumulated by the separation peels off and falls into the collection container 33. The inventors have found that this fine powder tends to contain many impurities having a low vapor pressure, and the purity of the product powder because the dropped fine powder is mixed into the product powder collected in the collection container 33. Was found to decrease.
[0024]
Therefore, the purification apparatus of the present invention shown in FIG. 1 is configured to reduce the mixing of fine powder. The configuration of the plasma torch, reaction tower, etc. is almost the same as that of the conventional apparatus of FIG. 3, but as shown in the figure, a receiving tray 21 and a suction box 25 for sucking fine particles are sucked into the inner wall of the cylindrical portion 32 of the reaction tower 31. The difference is that a fine particle collecting means 20 having a suction means is provided. The tray 21 has a shape in which a tapered cylindrical ring 22 having a gap with the inner wall of the cylindrical portion 32 opened at the top is attached to the inner periphery of the inner wall of the cylindrical portion 32 with a bottom portion 22a. A suction box 25 is provided on the outer periphery of the cylindrical portion 32 corresponding to the tray 21, and a number of suction holes 23 are passed through the circumference of the cylindrical portion 32 between the tray 21 and the suction box 25. The suction port 26 of the suction box 25 is electrically connected to the filter 38 via the suction pipe 27.
[0025]
Hereinafter, the operation of the purification apparatus of the present invention will be described. The raw material powder put into the frame 1 of the plasma torch 11 is melted and purified at a high temperature and falls into the reaction tower 31. At this time, the fine powder floats above the reaction tower 31. The fine powder adheres to the inner wall of the reaction tower as shown in the figure, and peels off and falls to the lower part.
[0026]
In the refining apparatus of the present invention, since the tray 21 is provided on the inner wall of the reaction tower, fine powder that adheres to and falls on the inner wall of the reaction tower is received by the tray 21 and is passed from the suction hole 23 through the suction port 26. And is collected by the filter 38.
[0027]
Note that the medium-sized powder having a particle size smaller than that of the product powder is sucked from the exhaust port 35 and collected by the cyclone 36 and the filter 37. Therefore, a spherical powder containing almost no fine powder is obtained as the product powder collected in the collection container 33. As a result, the product powder recovered in the recovery container 33 is a large-powder product powder that is less contaminated with impurities and has a high purity. In addition, as mentioned above, the fine powder, medium powder, and large powder referred to here have relative particle sizes that are compared. Generally, the fine powder is 10 μm or less, the medium powder is 10 to 30 μm, and the large powder is 30 μm. That's it.
[0028]
[Embodiment 2]
Next, the powder spheroidizing apparatus of the present invention will be described. Since the spheroidizing apparatus of the second embodiment uses exactly the same apparatus as the purification apparatus of the first embodiment, it will be described with reference to FIG.
[0029]
The raw material powder charged into the frame 2 of the plasma torch 11 is melted at a high temperature and becomes spherical, falls into the reaction tower 31 and is collected in the collection container 33 as spherical powder. At this time, the fine powder having a small particle size floats on the upper part of the reaction tower, adheres to the inner wall of the upper part of the reaction tower as shown in the figure, peels off and falls to the lower part. Therefore, in the conventional apparatus of FIG. 3, fine powder is mixed in the product powder collected in the collection container. For this reason, classification is required to obtain only a spherical powder having a particle size with good sintering moldability, but classification is difficult due to the fine particles.
[0030]
In the refining device of the present invention, since the tray 21 is provided on the inner periphery of the inner wall, the fine particles adhering to the inner wall of the reaction tower are received by the tray 21 and sucked from the suction hole 23 through the suction port 26, and filtered. 38. The medium-sized powder is sucked from the lower exhaust port 35 and collected by the cyclone 36 and the filter 37.
[0031]
Thereby, it classify | categorizes and collects with fine powder, medium-sized powder, and large-sized powder (product powder). For this reason, the product powder recovered in the recovery container 33 can be obtained without classifying only spherical powder having a good sintering moldability and containing almost no fine powder or medium powder. The fine powder, medium powder, and large powder referred to here also have the relative particle sizes described above.
[0032]
[Embodiment 3]
FIG. 2 is a cross-sectional view of the spheroidizing apparatus of the third embodiment. In the spheroidizing apparatus of the second embodiment, the powder can be classified and collected as fine powder, medium powder, and large product particle size, but in the third embodiment, the tray is more actively provided at the exhaust port at the bottom of the reaction tower. It is a thing.
[0033]
Referring to FIG. 2, in the spheroidizing apparatus of the third embodiment, in addition to the fine powder collecting means 20 at the upper part of the reaction tower of the second embodiment, a middle powder collecting means 20 ′ having the same shape is provided at the lower part. . That is, in addition to the upper tray 21 of the second embodiment, a lower tray 21 ′ is provided, and the lower tray 21 ′ is also provided with a tapered cylindrical ring 22 ′ having the same shape as the upper tray 21 on the inner periphery of the inner wall of the cylindrical portion 32. . As with the upper tray 21, a suction hole 23 ′ and a suction box 25 ′ are provided, and are conducted to the cyclone 36 and the filter 37 through the air inlet 26 ′.
[0034]
Since the medium-sized powder of the second embodiment is more actively collected by the lower tray 21 ', the spherical powder collected in the collection container 33 further excludes powders having a particle size other than the product particle size, and a product powder having a uniform particle size. Is obtained.
[0035]
In the third embodiment, the medium particle collecting means 20 ′ is shared with the lower exhaust port 35 of the second embodiment, but the medium particle collecting means 20 ′ may be provided separately from the exhaust port 35.
[0036]
【Example】
[Example 1]
Example 1 compared the scouring effect of the purification of W powder using the purification apparatus of the present invention of FIG. 1 and the conventional apparatus of FIG. 4 to 6 show micrographs of the raw material and the obtained powder. FIG. 4 shows the raw material powder, and FIGS. 5 and 6 show the spherical powder recovered in the recovery containers of the conventional apparatus and the apparatus of the present invention, respectively. The crushed raw material powder shown in FIG. 4 is neatly spheroidized in both FIGS. However, the spherical powder produced by the conventional apparatus shown in FIG. 5 has fine particles adhered to the surface, whereas the spherical powder produced by the apparatus of the present invention shown in FIG. It can be seen that the powder was separated by the fine powder collecting means and only the large powder was recovered in the recovery container.
[0037]
Table 1 shows the results of analyzing impurities for the spherical powder obtained by the conventional apparatus shown in FIG. 5 and the spherical powder obtained by the apparatus of the present invention shown in FIG. From Table 1, impurities are significantly reduced from the raw material powder in both the conventional apparatus and the present invention apparatus, and a scouring effect is recognized. However, in the apparatus of the present invention, all impurities are reduced in each stage as compared with the conventional apparatus, and the refining effect by the apparatus of the present invention is remarkably improved.
[0038]
[Table 1]

[0039]
[Example 2]
Example 2 compared the refinement | purification effect similarly to Example 1 using the refinement | purification apparatus of this invention, and the conventional apparatus about refinement | purification of Mo powder. 7 to 9 show micrographs of the powder. FIG. 7 shows the raw material powder, and FIGS. 8 and 9 show the spherical powder recovered in the recovery containers of the conventional apparatus and the apparatus of the present invention, respectively. In contrast to the raw material powder shown in FIG. 7, the recovered spherical powder obtained by the conventional apparatus shown in FIG. 8 has a shape in which a large amount of fine powder adheres to the surface and aggregates, and the spherical shape is hardly recognized. On the other hand, the recovered spherical powder by the apparatus of the present invention in FIG. 9 is finely spheroidized on the surface without adhesion of fine particles. That is, according to the device of the present invention, it can be seen that the fine powder is separated and only the large powder is recovered in the recovery container.
[0040]
Table 2 shows the results of analyzing impurities in the spherical powder obtained by the conventional apparatus shown in FIG. 8 and the spherical powder obtained by the apparatus of the present invention shown in FIG. From Table 2, it can be seen that since the fine powder is not separated in the conventional apparatus, impurities in the recovered powder are hardly reduced from the raw material powder, and the scouring effect is not recognized so much. On the other hand, since the fine powder is separated in the apparatus of the present invention, the impurities are reduced to almost half or less from the raw powder, and a sufficient scouring effect is recognized. As described above, the apparatus of the present invention is remarkably improved in the scouring effect as compared with the conventional apparatus.
[0041]
[Table 2]

[0042]
[Example 3]
In Example 3, the Al ₂ O ₃ powder was subjected to a spheronization test using the spheroidizing apparatus of the present invention in FIG. 1 similar to Examples 1 and 2 and the conventional apparatus in FIG. Table 3 shows the test results. First, how to read the table is explained. The column for the collection container and the cyclone is the powder collected in the collection container 33 and the cyclone 36 for both the conventional method and the method of the present invention, the column for the filter is the powder collected by the filter 37 for the conventional method, and the method of the present invention is the

filter

37, 38 shows the recovered powder. The ratio by particle size is 100% in total, indicating the particle size distribution for each particle size in Wt%.
[0043]
[Table 3]

[0044]
The site-specific recovery rate indicates the recovery rate of the powder recovered in the above-described recovery container, cyclone, and filter. The recovery efficiency according to the particle size indicates the ratio of large powder in the collection container, medium powder in the cyclone, and fine powder in the filter with respect to the amount of powder collected at each part.
[0045]
From Table 3, it can be seen that the method of the present invention is less mixed with medium and fine powders and the recovery rate of large powders is improved from 89% to 95% in the collection container as compared with the conventional method. It can also be seen that in the cyclone, the mixture of fine particles decreased and the recovery rate of medium particles improved from 93% to 96%.
[0046]
[Example 4]
In Example 4, a spheronization test was performed on the SiO ₂ powder using the spheroidizing apparatus of the present invention shown in FIG. 1 and the conventional apparatus shown in FIG. Table 4 shows the test results. The way of reading the table is the same as in Table 3.
[0047]
[Table 4]

[0048]
From Table 4, the method of the present invention improves the recovery rate of large particles from 82% to 93% in the recovery container as in Example 3, and the recovery rate of medium particles in the cyclone is 66 from the conventional method. It can be seen that the percentage has improved from 77% to 77%.
[0049]
As shown in Examples 3 and 4 above, according to the method of the present invention, classification is better performed with less mixing of powders having different particle sizes in the collection container and the cyclone than in the conventional method. Depending on the application, it is possible to select and use medium-grained powder with little mixing of fine-grained powder recovered with a cyclone.
[0050]
As described above, according to the method and apparatus for synthesizing / purifying powder by thermal plasma according to the embodiment of the present invention, the fine powder collecting means is provided on the inner wall of the reaction tower, thereby collecting the fine powder floating around the inner wall. In addition, since only spherical particles not containing impurities are dropped into the collection container, a high-purity powder can be obtained.
[0051]
Further, according to the method and apparatus for spheroidizing powder by the thermal plasma of the present invention, the fine particle collecting means is provided on the inner wall of the reaction tower, and the fine particles floating in the reaction tower and adhering to the inner wall are collected and the remaining spherical particles Only in a collecting container, spherical particles having a good moldability and a small particle size can be obtained.
[0052]
Also, the method and apparatus for spheroidizing powder by thermal plasma according to the present invention is provided with fine particle collecting means and medium particle collecting means at the upper and lower parts of the reaction tower, and floats around the upper inner wall by the upper fine particle collecting means. By collecting the fine powder, collecting the medium powder floating around the inner wall of the lower part of the reaction tower by the lower medium powder collecting means, and collecting the remaining large powder in the recovery container at the bottom of the reaction tower. A spherical powder having a uniform particle size can be obtained for each particle size.
[0053]
The fine powder collecting means and the medium fine powder collecting means include a fine powder containing impurities concentrated on the inner walls of the upper and lower parts of the reaction tower, a receiving tray for receiving a spherical powder having a small particle size, and a suction means for sucking the fine powder collected in the receiving tray. The above object can be easily achieved.
[0054]
【The invention's effect】
As described above, according to the method and apparatus for synthesizing / purifying powder by thermal plasma according to the present invention, it is possible to obtain a high-purity powder with less impurities mixed in compared with the conventional apparatus, so that the performance of the synthetic powder is improved and a new application is opened. . In addition, in the method and apparatus for spheroidizing powder by thermal plasma according to the present invention, a spherical powder having a uniform predetermined particle size with good sintering processability and the like that does not contain fine particles can be obtained, so that the quality of sintered products and the like is improved.
[Brief description of the drawings]
1 is a cross-sectional view of a refining apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of a spheroidizing apparatus according to Embodiment 2 of the present invention. FIG. 3 is a cross-sectional view of a conventional refining / spheroidizing apparatus. Photomicrograph of raw powder of Invention Example 1 [FIG. 5] Photomicrograph of purified powder by conventional apparatus of Example 1 of the present invention [FIG. 6] Micrograph of purified powder by apparatus of the present invention of Example 1 [FIG. Photomicrograph of raw powder of Example 2 of the present invention [FIG. 8] Photomicrograph of purified powder by conventional apparatus of Example 2 of the present invention [FIG. 9] Photomicrograph of purified powder by apparatus of the present invention of Example 2 Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plasma flame | frame, 3 Raw material powder, 4 Product powder (large particle powder), 5 Fine particle powder, 6 Medium particle powder, 11 Plasma torch, 12 Quartz tube, 13 High frequency induction coil, 15 Raw material hopper, 16 Raw material supply tube, 20 Fine particle powder Collecting means, 20 'medium grain collecting means, 21, 21' saucer, 22 taper cylindrical ring, 23 suction hole, 25 suction box, 26 suction port, 27 suction pipe, 31 reaction tower, 32 cylindrical part, 33 collection container, 34 Top cover, 35 Exhaust port, 36 Cyclone, 37 filter, 38 filter

Claims

原料粉末をプラズマフレームにより加熱溶融して粉末を合成／精製し、該合成／精製粉末を反応塔底部の回収容器に回収する粉末の合成／精製方法において、該反応塔内壁に微粒粉収集手段を設け、該微粒粉収集手段により反応塔内に浮遊し内壁に付着する不純物を含む微粒粉を収集し、不純物の少ない残部粉末粒子を落下させて前記回収容器に回収することにより、純度の高い製品粉末を得ることを特徴とする熱プラズマによる粉末の合成／精製方法。In a method for synthesizing / purifying powder, in which raw material powder is heated and melted by a plasma flame to synthesize / purify the powder, and the synthesized / purified powder is collected in a recovery container at the bottom of the reaction tower. A high-purity product is provided by collecting fine particles containing impurities adhering to the inner wall floating in the reaction tower by the fine particle collecting means, and dropping the remaining powder particles with less impurities into the recovery container. A method for synthesizing / purifying powder by thermal plasma, characterized in that the powder is obtained.

原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に回収する粉末の球状化方法において、該反応塔内壁に微粒粉収集手段を設けて、該微粒粉収集手段により反応塔内に浮遊し内壁に付着する微粒粉を収集し、微粒粉が減少した残部球状粒子を落下させて前記回収容器に回収することにより、微粒粉の混入が少ない粒度の揃った球状粒子を得ることを特徴とする熱プラズマによる粉末の球状化方法。In a powder spheronization method in which the raw material powder is heated and spheronized by a plasma flame, and the spherical powder is recovered in a recovery container at the bottom of the reaction tower, a fine powder collecting means is provided on the inner wall of the reaction tower to collect the fine powder By collecting the fine particles floating in the reaction tower and adhering to the inner wall by means, dropping the remaining spherical particles with the reduced fine particles and collecting them in the collection container, the spherical particles with a uniform particle size with little mixed fine particles A method of spheroidizing powder by thermal plasma, characterized by obtaining particles.

原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に収集する粉末の球状化方法において、該反応塔内壁の上部側に微粒粉収集手段を設け、該内壁の下部側に中粒粉収集手段を設け、前記微粒粉収集手段により反応塔内上部に浮遊し内壁に付着する微粒粉を収集し、前記中粒粉収集手段により反応塔内下部に浮遊する中粒粉を収集し、残部大粒の球状粒子を落下させて前記回収容器に回収することにより、球状粒子を微粒粉と中粒粉と大粒粉とに分別して得ることを特徴とする熱プラズマによる粉末の球状化方法。In a powder spheronization method in which the raw material powder is heated and spheronized by a plasma flame, and the spherical powder is collected in a recovery container at the bottom of the reaction tower, a fine powder collecting means is provided on the upper side of the inner wall of the reaction tower, and the inner wall A medium-sized powder collecting means is provided on the lower side of the reactor, and the fine-grained powder collecting means collects the fine powder that floats on the upper part of the reaction tower and adheres to the inner wall, and the medium-sized powder collecting means floats on the lower part of the reaction tower. Powder by thermal plasma characterized by collecting granular powder, dropping the remaining large spherical particles and collecting them in the collection container to separate the spherical particles into fine powder, medium powder and large powder Spheroidization method.

前記微粒粉収集手段と中粒粉収集手段のそれぞれまたは一方を２以上備えることにより、さらに粒度を細分別して回収することを特徴とする請求項３に記載の熱プラズマによる粉末の球状化方法。4. The method for spheroidizing powder by thermal plasma according to claim 3, wherein the particle size is further subdivided and collected by providing two or more of each of the fine powder collecting means and the medium fine powder collecting means.

原料粉末をプラズマフレームにより加熱溶融して粉末を合成／精製し、該合成／精製粉末を反応塔底部の回収容器に回収する粉末の精製装置において、反応塔内壁に該反応塔内に浮遊し内壁に付着する不純物を含む微粒粉を収集する微粒粉収集手段が設けられ、反応塔底部に不純物の少ない残部粉末粒子を落下させて回収する回収容器が設けられた、純度の高い製品粉末が得られることを特徴とする熱プラズマによる粉末の合成／精製装置。In a powder purification apparatus for synthesizing / purifying powder by heating and melting raw material powder with a plasma flame and collecting the synthesized / purified powder in a recovery container at the bottom of the reaction tower, the inner wall floats in the reaction tower on the inner wall of the reaction tower. A fine powder collecting means for collecting fine powder containing impurities adhering to the reactor is provided, and a high-purity product powder is obtained in which a recovery container is provided for dropping and collecting the remaining powder particles with low impurities at the bottom of the reaction tower. An apparatus for synthesizing / purifying powder using thermal plasma.

前記微粒粉収集手段は、反応塔内壁内周に設けられた受け皿と該受け皿に集まる微粒粉を吸引する吸引手段とを備えたことを特徴とする請求項５に記載の熱プラズマによる粉末の合成／精製装置。6. The synthesis of powder by thermal plasma according to claim 5, wherein the fine powder collecting means comprises a tray provided on the inner periphery of the inner wall of the reaction tower and a suction means for sucking the fine powder collected in the tray. / Purification equipment.

原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に回収する粉末の球状化装置において、反応塔内壁に該反応塔内に浮遊し内壁に付着する微粒粉を収集する微粒粉収集手段が設けられ、反応塔底部に前記微粒粉が減少した残部球状粒子を落下させて回収する回収容器が設けられた、微粒粉の混入が少ない粒度の揃った球状粒子が得られることを特徴とする熱プラズマによる粉末の球状化装置。In a powder spheroidizing apparatus in which raw material powder is heated and melted into a spherical shape by a plasma flame, and the spherical powder is recovered in a recovery container at the bottom of the reaction tower, the fine powder floats on the inner wall of the reaction tower and adheres to the inner wall Is provided with a collecting means for collecting fine particles, and a recovery container is provided for dropping and collecting the remaining spherical particles with the reduced fine particles at the bottom of the reaction tower. An apparatus for spheroidizing powder using thermal plasma.

前記微粒粉収集手段は、反応塔内壁内周に設けられた受け皿と該受け皿に集まる微粒粉を吸引する吸引手段とを有することを特徴とする請求項７に記載の熱プラズマによる球状粉末の球状化装置。The spherical powder of spherical powder by thermal plasma according to claim 7, wherein the fine powder collecting means includes a tray provided on the inner periphery of the inner wall of the reaction tower and a suction means for sucking the fine powder collected in the tray. Device.

原料粉末をプラズマフレームにより加熱して溶融球状化し、該球状粉末を反応塔底部の回収容器に収集する粉末の球状化装置において、該反応塔内壁の上部側に反応塔内上部に浮遊し内壁に付着する微粒粉を収集する微粒粉収集手段が設けられ、該内壁の下部側に反応塔内下部に浮遊する中粒粉を収集する中粒粉収集手段が設けられ、反応塔底部に残部大粒の球状粒子を落下させて回収する回収容器が設けられた、球状粒子を微粒粉と中粒粉と大粒粉とに分別して得られることを特徴とする熱プラズマによる粉末の球状化装置。In a powder spheroidizing apparatus in which the raw material powder is heated and melted into a spherical shape by a plasma flame, and the spherical powder is collected in a recovery vessel at the bottom of the reaction tower, it floats on the upper side of the inner wall of the reaction tower and floats on the inner wall. A fine powder collecting means for collecting the adhering fine powder is provided, and a medium powder collecting means for collecting the medium powder floating in the lower part of the reaction tower is provided on the lower side of the inner wall. An apparatus for spheroidizing powder by thermal plasma, comprising a collection container for dropping and collecting spherical particles, and obtained by separating spherical particles into fine powder, medium powder and large powder.

前記微粒粉収集手段と中粒粉収集手段は、それぞれ反応塔内壁内周に設けられた受け皿と該受け皿に集まる粉末を吸引する吸引手段とを備えることを特徴とする請求項９に記載の熱プラズマによる粉末の球状化装置。10. The heat according to claim 9, wherein each of the fine powder collecting means and the medium powder collecting means includes a tray provided on the inner periphery of the inner wall of the reaction tower and a suction means for sucking the powder collected in the tray. Powder spheroidizing device using plasma.

前記微粒粉収集手段と中粒粉収集手段のそれぞれまたは一方を２以上備えたことを特徴とする請求項１０に記載の熱プラズマによる粉末の球状化装置。11. The apparatus for spheroidizing powder by thermal plasma according to claim 10, wherein two or more of each of the fine particle collecting means and the medium particle collecting means are provided.