JPS58110601A - Belt type reducing furnace for metallic powder and operating method thereof - Google Patents

Abstract

PURPOSE:To improve the reducing efficiency of a reducing gas and the quality and stabilization of metallic powder by providing air permeability to a belt for moving unreduced metallic powder continuously to the furnace and supplying the reducing gas to the inside of furnace walls in such a way as to flow through the belt. CONSTITUTION:Metallic powder 19 is packed in a hopper 18, and the inside of furnace walls is heated. While a reducing gas is kept introduced through an introducing port 27 into furnace walls 31, an endless track belt 12 made of meshed steel is run in a direction A. The powder 19 delivered at a specified rate from the hopper 18 is heated from a supply area 15 to a heating area 16, and contacts with the reducing gas passing through the belt 12, by which the powder is reduced. The residual reducing gas after used for the reduction is discharged through a discharging port 21. Here, the powder 19 sinters to each other and loses fluidity; therefore, the powder does not drop through the belt 12. The reducing gas is discharged after the gas intersects with the belt 12 and the laminar powder 19 through the openings 22 of the holding means 24 of the belt 12. The gas is brought into contact with the 100% powder 19 by the projecting plates 26 on the furnace walls on both sides of the means 24.

Description

【発明の詳細な説明】 本発明は、焼結部品等の原材料となる鉄粉等の金属粉末
を還元処理するためのベルト式還元炉及びその操業方法
に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a belt-type reduction furnace for reducing metal powder such as iron powder, which is a raw material for sintered parts, and a method for operating the same.

周知のように焼結部品の製造工程においては。As is well known, in the manufacturing process of sintered parts.

分散惨化型合金等の特殊な場合を除き、原材料となる鉄
粉等の金属粉末の表面に酸化物層が存在することは焼結
性の点から好ましくない。しかしながら焼結部品■金属
粉末の製造方法として広く採用されているアトマイズ法
によ吟得られた金属粉末は、その製法上必然的に表面が
酸化され、またその他の方法により得られた金属粉末も
表面が酸化されていることが多いため、多くの場合この
金属粉末を還元処理しておく必要がある。Except for special cases such as dispersion type alloys, the presence of an oxide layer on the surface of metal powder such as iron powder as a raw material is undesirable from the viewpoint of sinterability. However, metal powder obtained by the atomization method, which is widely adopted as a manufacturing method for sintered parts and metal powder, inevitably has an oxidized surface due to the manufacturing method, and metal powder obtained by other methods also Since the surface is often oxidized, it is often necessary to reduce the metal powder.

上述のような金属粉末の還元処理に使用される還元炉と
しては、スチールベルト式連続還元炉がよく用いられる
。この中でも第１図に示すように。A steel belt continuous reduction furnace is often used as the reduction furnace used for the above-mentioned reduction treatment of metal powder. Among these, as shown in Figure 1.

鋼等からなる無限軌道金属製ベルト１の上面側の空間を
炉！１２及びガスシール用ローラう、うによって区画し
て炉室■を形成し、この炉室４をベルト１の進行方向子
Ｎｉｌ側からｉｌｊに供給域５．加熱域６、冷却域γと
し、供給域５には未還元金属粉末例えば鉄粉８をベルト
１上に供給するための本ツバ−９を設け、また加熱域６
には図示しない加熱手段を設け、さらに冷却域７の加熱
域６寄りの位置に還元性ガスを尋人するｒこめの導入口
１０を設けるとともに加熱域６の供給Ｍ５寄りの位置に
ガス排出口１１を設けた金属粉末用ベルト式還元炉が知
られている。この還元炉を用いて鉄粉を処理する場合に
ついて説明すると１表面が鉄酸化物すなわちＦｅＯ、Ｆ
ｅ２０ｍ　若しくはＦｓ３０４ｊＣよッテ覆われた未還
元鉄粉８は、ホッパー９の下端からベルト１上にそのベ
ルト１の走行に伴って連続的かつ電域的に切出される。The space on the top side of the endless track metal belt 1 made of steel etc. is a furnace! 12 and gas sealing rollers, a furnace chamber 4 is formed, and this furnace chamber 4 is connected to a supply area 5. A heating zone 6 and a cooling zone γ are provided, and the supply zone 5 is provided with a main collar 9 for supplying unreduced metal powder, such as iron powder 8, onto the belt 1.
A heating means (not shown) is provided in the cooling area 7, and an inlet 10 for introducing the reducing gas is provided at a position close to the heating area 6 of the cooling area 7, and a gas discharge port is provided at a position close to the supply M5 of the heating area 6. A belt-type reduction furnace for metal powder equipped with a metal powder is known. To explain the case where iron powder is treated using this reduction furnace, one surface is made of iron oxide, that is, FeO, F
The unreduced iron powder 8 covered with e20m or Fs304jC is continuously cut out from the lower end of the hopper 9 onto the belt 1 as the belt 1 runs.

この切出し速度はベルト１の走行速度、ホッパー９内の
未還元鉄粉の高さによって決定される。ベルト１上に切
出された未還元鉄粉８は、ベルト１の走行に伴い供給域
５から加熱域６へ連続して移行して、その加熱域６内に
おいて高温に加熱されろとともに導入口１０から導入さ
れた還元性ガス、例えばアンモニア分解ガス（５Ｌ＋Ｎ
、）に曝され、未還元鉄分の表面の酸化物Ｆｅｄ、　Ｆ
ｓ、　Ｏｓ、　Ｆｅ、　０．が次の反応式によって還元
される。This cutting speed is determined by the running speed of the belt 1 and the height of the unreduced iron powder in the hopper 9. The unreduced iron powder 8 cut out on the belt 1 continuously moves from the supply zone 5 to the heating zone 6 as the belt 1 runs, is heated to a high temperature in the heating zone 6, and then passes through the inlet. Reducing gas introduced from 10, for example ammonia decomposition gas (5L+N
), the surface oxides of unreduced iron are exposed to
s, Os, Fe, 0. is reduced by the following reaction formula.

３Ｆｅ、　０＋Ｈ，−ｅ２Ｆｅ３０．　＋ｕ、　ＯＦｅ
、　Ｏｓ　＋Ｈ，−ｅ３Ｆｅｏ＋Ｈ，ＯＦ　ａ　Ｏ＋Ｈ
１−ｅＦ　ａ　４−Ｈ，０このようにして還元された鉄
粉８は、冷却域７に移行して冷却された後、炉外へ送り
出される。一方、導入口ｌＯから加熱域６に導入されて
未還元鉄粉８の還元に供された後のガスは、その大部分
が排出口１１を経て炉外へ排出され、一部はホッパー９
内の未還元鉄粉８の粉末端子間の空隙を通って外部へ排
出される。3Fe, 0+H, -e2Fe30. +u, OFe
, Os +H, -e3Feo+H, OF a O+H
1-eF a 4-H,0 The iron powder 8 thus reduced is transferred to the cooling zone 7 and cooled, and then sent out of the furnace. On the other hand, most of the gas that has been introduced into the heating zone 6 from the inlet lO and used for reducing the unreduced iron powder 8 is discharged to the outside of the furnace through the outlet 11, and a portion is left in the hopper 9.
The unreduced iron powder 8 inside is discharged to the outside through the gap between the powder terminals.

ところで、上述のような還元炉を操業するＫは従来１次
のような問題があった。By the way, K operating the above-mentioned reduction furnace has conventionally had the following first-order problem.

（１）　　還元ガスの還元効率が低く、大量のガスを必
要とする。(1) The reduction efficiency of reducing gas is low and a large amount of gas is required.

すなわち、供給される還元ガスのほとんどが還元に寄与
されずシこ炉外へ放出されており、これは炉内において
層状となった鉄粉の上面部分Ｏ，みを還元ガスが流れる
ために、１−吠鉄粉の下面では鉄粉と還元ガス（主とし
てＨ，ガス）が接触しにくいことによる。また、還元ガ
ス（Ｈｚガス）の変化域は、還元前後の鉄粉０！斌の低
減量あるいは還元中のＨ，Ｏの発生麓により推定が可能
であり、還元効率は（還元中のＨ１ガス消費量）÷（供
給ガス輩）で表わされるが、従来の還元炉によれば約１
〔１％と低かった。In other words, most of the supplied reducing gas does not contribute to reduction and is released outside the furnace. This is because the reducing gas flows only through the upper surface of the layered iron powder inside the furnace. 1- This is because the iron powder and reducing gas (mainly H, gas) are difficult to come into contact with each other on the lower surface of the iron powder. In addition, the change range of reducing gas (Hz gas) is 0 iron powder before and after reduction! It can be estimated by the amount of reduction in gas or the amount of H and O generated during reduction, and the reduction efficiency is expressed as (H1 gas consumption during reduction) ÷ (supplied gas). About 1
[It was as low as 1%.

したがって、ガスの原料費、ガスの分解に要するエネル
ギー、還元炉内でのガスの昇温エネルギーが大きいとい
う問題が生じた。ここで分解に要するエネルギーとは、
原料のＮ％を９００−１０００℃に加熱し、触媒を介し
て（２ＮＮ（Ｊ＝Ｎｓ＋３　Ｈｚ　）へ分解するのに必
要なエネルギー１あり、昇温エネルギーとは１分解後に
一旦常温まで冷却した後、再び還元温度である８００−
１９００℃に昇温するのζζ必要とするエネルギーであ
る。Therefore, problems arose in that the raw material cost of the gas, the energy required to decompose the gas, and the energy required to raise the temperature of the gas in the reduction furnace were large. The energy required for decomposition is
There is 1 energy required to heat N% of the raw material to 900-1000℃ and decompose it into (2NN (J = Ns + 3 Hz) through a catalyst.The heating energy is 1. After cooling to room temperature after decomposition, , again at the reduction temperature of 800-
This is the energy required to raise the temperature to 1900°C.

このように、従来の還元炉及びその操業方法によれば、
還元ガスの原料費１分解、再昇温エネルギーに要する費
用等ランニングコストの占める比率が高くなる欠点があ
った。In this way, according to the conventional reduction furnace and its operating method,
There is a drawback that running costs such as the raw material cost of the reducing gas, the cost of decomposition, and the cost of reheating energy are high.

（２）粉末冶金用鉄分としての品質が低く、ばらつきが
大きい。(2) The quality of iron for powder metallurgy is low and there are large variations.

前述のように９Ｍ状許粉の下部は、上部に比べて還元ガ
スと接触しにくいため、還元されにくくなる。この結果
、Ｎ死後の鉄粉の酸素量（以下。As mentioned above, the lower part of the 9M powder is less likely to come into contact with the reducing gas than the upper part, and is therefore less likely to be reduced. As a result, the amount of oxygen in the iron powder after N death (see below).

水素還元減量と呼ぶ）は、全体としては一定値以下に低
下しているが、還元を受けたロフトの中には水素還元量
の低い鉄粉と高い鉄粉が混在している。Although the hydrogen reduction loss (referred to as hydrogen reduction loss) has decreased to below a certain value as a whole, iron powder with a low hydrogen reduction amount and iron powder with a high hydrogen reduction amount coexist in the loft that has undergone reduction.

鉄粉を焼結部品として使用する場合、その強度を増加さ
せるために鉄粉に銅粉、グラファイト粉を添加し圧粉成
形後に焼結するが、上述のような鉄粉を粉末冶金用の原
料として使用すると、焼結時に鉄粉表面の残存酸素は添
加したグラファイト粉と反応じ、脱炭素現象を生ずるの
で、同一部品内に水素還元減量の高い鉄粉が存在すると
いうことは、４の部分の脱炭素量が大となり、焼結後に
スポット的に炭素鰍の低い部分が生じろ。その結果、焼
結部品としての強度が低下するという問題が生ずる。When iron powder is used as a sintered part, copper powder and graphite powder are added to the iron powder to increase its strength, and the powder is compacted and then sintered. When used as an iron powder, the residual oxygen on the surface of the iron powder reacts with the added graphite powder during sintering, causing a decarbonization phenomenon. Therefore, the presence of iron powder with a high hydrogen reduction loss in the same part means that The amount of decarbonization becomes large, and spots with low carbon content appear after sintering. As a result, a problem arises in that the strength of the sintered part is reduced.

また、還元炉に供給される前の原料鉄粉の水素還元減量
は、所定範囲のばらつきを有しているがベルト式還元炉
ではその構造上、特に還元カスとの接触が少ない層状Ｑ
火粉の下部で上記ばらつきを受けやすく焼結部品の強度
及び焼結型等のばらつきに影響を与える。In addition, the hydrogen reduction loss of the raw iron powder before being supplied to the reduction furnace varies within a certain range, but due to the structure of the belt-type reduction furnace, the layered Q
The lower part of the powder is susceptible to the above-mentioned variations, which affects the strength of the sintered parts and variations in the sintering mold.

以上、　（１）、　（２）にて述べたように、従来のベ
ルト式還元炉を用いて還元した鉄粉は、粉末冶金用鉄粉
としての品質レベルが低く１強度上のばらつきが大きい
。また、鉄粉以外の金属粉末においても同様のことがい
える。As described in (1) and (2) above, iron powder reduced using a conventional belt-type reduction furnace has a low quality level as iron powder for powder metallurgy, and has large variations in strength. Furthermore, the same can be said of metal powders other than iron powder.

本発明は、上述の問題点に鑑みなされたものであり。The present invention has been made in view of the above-mentioned problems.

（１）金属粉末の還元工程での還元ガスの還元効率を向
上させることにより、消費ガス量を低減させ、消費ガス
量の低減に伴い還元ガスへの分解エネルギー、還元炉内
での昇温エネルギーを低減し金属粉末のコスト低減をは
かる。(1) By improving the reduction efficiency of reducing gas in the metal powder reduction process, the amount of gas consumed is reduced, and with the reduction in the amount of gas consumed, energy for decomposition into reducing gas and energy for heating up in the reduction furnace are reduced. This aims to reduce the cost of metal powder.

（２）金属粉末の品質を向上かつ安定させる。(2) Improve and stabilize the quality of metal powder.

上記（１１，＋２１を達成することを目的とする。The aim is to achieve the above (11, +21).

すなわち１本発明方法の要旨とするところは。In other words, the gist of the method of the present invention is as follows.

未還元金属粉末をホブパーからその下方の無端金に４Ｉ
Ｉｌｌ状ベルト上に連続的に供給し、そのベルトの走行
によって未還元金属粉末を加熱炉に連続的に移行させ、
その加熱炉に還元性ガスを導入してベルト上の未還元粉
末を高温還元性雰囲気にて連続的に還元するようにした
金属粉末用ベルト式還元炉であって、前記ベルトに通気
性を持たせるとともに、前記ベルトを流通するようにし
還元ガスを炉壁内へ供給かつ排出することを特徴とする
。Unreduced metal powder is transferred from the hob par to the endless metal below.
The unreduced metal powder is continuously supplied onto an Ill-shaped belt, and as the belt runs, the unreduced metal powder is continuously transferred to a heating furnace.
A belt-type reduction furnace for metal powder in which a reducing gas is introduced into the heating furnace to continuously reduce unreduced powder on a belt in a high-temperature reducing atmosphere, and the belt has air permeability. At the same time, the belt is made to circulate so that the reducing gas is supplied into and discharged from the furnace wall.

そして上記発明方法が好適に実施される発明装置は、未
還元金属粉末を載置して連続的に移行させる無端金属環
核ベルトと該ベルトの駆動装置と前記ベルトの未還元金
属粉末が載置される部分を囲繞するよう配設された炉壁
と、該炉壁に設けられる還元ガスの供給口及び排出口と
、前記炉壁に設けられた未還元金属粉を前記ベルト上に
連続的に供給するホブパーと前記炉壁内に設けられ前記
ベルト上の未還元粉末を加熱する加熱手段とからなり、
前記ベルト上の未還元粉末を高混還九性！囲・気にて連
続的に還元するようにした金ｒ１４ｈＪ木用ベルト式還
元炉であって。The inventive apparatus in which the above-mentioned inventive method is suitably carried out includes an endless metal ring core belt on which unreduced metal powder is placed and transferred continuously, a drive device for the belt, and an unreduced metal powder on the belt is placed on it. a furnace wall arranged so as to surround a portion to be treated, a reducing gas supply port and a reducing gas discharge port provided in the furnace wall, and an unreduced metal powder provided in the furnace wall continuously onto the belt. It consists of a hob par to be supplied and a heating means provided in the furnace wall to heat the unreduced powder on the belt,
The unreduced powder on the belt is highly mixed! This is a belt-type reduction furnace for gold r14hJ wood that is designed to reduce continuously using surrounding air and air.

（１）　　前記ベルトに通気性を持たせ。(1) Provide breathability to the belt.

（２）前記炉壁の中央付近を前記ベルトより下方に位置
させ。(2) The vicinity of the center of the furnace wall is located below the belt.

（３）通気性を有するベルト保持具によりベルトを支持
し。(3) The belt is supported by a belt holder having breathability.

（４）前記炉壁の下方に還元ガスの導入口若しくは排出
口を設け。(4) A reducing gas inlet or outlet is provided below the furnace wall.

（５）前記炉壁の上方に還元ガスの排出口若しくは導入
口を設けることを特徴とする。(5) A reducing gas outlet or inlet is provided above the furnace wall.

以下１本発明の一実施例を図面に基づいて詳細に説明す
る。An embodiment of the present invention will be described in detail below with reference to the drawings.

第２図は０本発明の実施例に係るベルト式還元炉の正面
断面図である。無限軌道金属製ベルト１２は通気性を有
するメツシュスチールからできておリ、ローラに掛けら
れて駆動用ローラう２によって図上矢印入方向へ走行す
るよう連続的に駆動され上側を走行するベルト１２に金
属粉末を載置し連続的に移行させる。FIG. 2 is a front sectional view of a belt-type reduction furnace according to an embodiment of the present invention. The endless track metal belt 12 is made of breathable mesh steel, and is hung on rollers and is continuously driven by driving rollers 2 to run in the direction indicated by the arrow in the figure, so that the belt runs on the upper side. Metal powder is placed on 12 and transferred continuously.

上側のベルト１２は炉Ｈ１１４により覆われており。The upper belt 12 is covered by a furnace H114.

炉壁１４内はベルト１２の走行方向に対して、供給域１
５、加熱域１６．冷却城１７にわけられる供給域１５で
は、炉！ｉｌｌ上部にホッパー１８が固定され、ホッパ
ー１８よりベルト１２上へ一定量の金属粉末１９’が一
定の厚さで供給される。炉１１１１１の側端部はローラ
１うとベルト１２との接触でシールされている。また、
第５図に示すように、上側のベルト１２の下面と下部の
炉壁２０の上面とは摺接しておりこのため、メツシュス
チールベルト１２よす流動性の高い金属粉末１９が洩れ
ても炉Ｈ１２０の上面で規制されて、その量は微１であ
る。ホッパー１８よりベルト１２の道行方向側の炉！！
１１１上部には、還元ガスの排出口２１が設けられてい
る。Inside the furnace wall 14, there is a supply area 1 with respect to the running direction of the belt 12.
5. Heating area 16. In the supply area 15 divided into cooling castles 17, there is a furnace! A hopper 18 is fixed to the upper part of the ill, and a certain amount of metal powder 19' is supplied from the hopper 18 onto the belt 12 at a certain thickness. The side edges of the furnace 11111 are sealed by contact with the rollers 1 and the belt 12. Also,
As shown in FIG. 5, the lower surface of the upper belt 12 and the upper surface of the lower furnace wall 20 are in sliding contact, so that even if the highly fluid metal powder 19 leaks from the mesh steel belt 12, the furnace It is regulated by the upper surface of H120, and its amount is only 1 minute. Furnace on the traveling direction side of the belt 12 from the hopper 18! !
At the upper part of 111, a reducing gas outlet 21 is provided.

加熱域１６では、第１図に示すように炉壁下部２１が一
段下がっており、炉壁下部２１とベルト１２との間には
、第６図に示すように上面に複数の開口部２２を有し１
足２うにて支持された保持共へが挿入されて保持具洒の
上面とベルト１２の下面が摺接する。In the heating zone 16, the lower part of the furnace wall 21 is lowered one step as shown in FIG. Has 1
The holder supported by the legs 2 is inserted, and the upper surface of the holder and the lower surface of the belt 12 come into sliding contact.

保持具２１１の両側は炉壁２５より突出板２６が出てお
り保持具鮨の両側よりガスを逃がさないようにしている
。また、炉壁下部２１の冷却域１７寄りには、還元ガス
を導入するための導入口２７が設けられている。Projecting plates 26 protrude from the oven wall 25 on both sides of the holder 211 to prevent gas from escaping from both sides of the holder. Further, an inlet 27 for introducing reducing gas is provided in the lower part 21 of the furnace wall near the cooling zone 17.

冷却域１７では、第５図に示されるように炉壁土部２８
が加熱域に比べて一段低く、炉壁下部２９がベルト１２
の下面と摺接するよう位置し、炉１２２８の側端部はロ
ーラう０とベルト１２との接触でシールされている。In the cooling zone 17, as shown in FIG.
is one step lower than the heating area, and the lower part of the furnace wall 29 is the belt 12.
The side end of the furnace 1228 is sealed by the contact between the roller cage 0 and the belt 12.

炉壁のベルト１２の進行方向に対する横断面を比べると
、冷却域１７が最も小さくなっている。Comparing the cross sections of the furnace wall with respect to the traveling direction of the belt 12, the cooling zone 17 is the smallest.

次に本実施例の作用につき説明する。Next, the operation of this embodiment will be explained.

ホッパー１８に金属粉末１つを充填し加熱手段により炉
壁内を加熱し、導入口２７より還元ガスを炉壁内′５１
へ導入した状態で駆動ローラう２を回転させてベルト１
２を図上Ａ方向に走行させると、ホッパー１８より定量
切出されベルト１２上に載置された金属粉末１つは、供
給域１５から加熱域１６にかけて加熱されるとともに導
入口２７より保持具２４の開口部２２よりメツシュスチ
ールベルト１？を通過する還元ガスに接触し、還元が行
われろ。還元を行った残轢の還元ガスは゛、排出口２１
より外部へ排出される。ここで層状金属粉末１９は、供
給域１５から加熱域１６にかけて一定温度に加熱される
と金属粉末１９同志が焼結してケーキ状とな轢、流動性
を失う。流動性を失った層状金属粉末１つはスチールメ
ツシュベルト１？より落下しない。また、導入口２７よ
り供給された還元ガスは、ベルト１２の保持具２１１の
開口部２２を経てスチールメツシュベルト１２及び層状
金属粉末１９と交差した後、排出口２１よ轢排出される
が。The hopper 18 is filled with one metal powder, the inside of the furnace wall is heated by the heating means, and the reducing gas is introduced into the furnace wall '51 through the inlet 27.
The drive roller 2 is rotated while the belt 1 is inserted into the
2 is run in the direction A in the diagram, one metal powder cut out in a fixed amount from the hopper 18 and placed on the belt 12 is heated from the supply zone 15 to the heating zone 16, and is transferred from the inlet 27 to the holder. Mesh steel belt 1 from opening 22 of 24? It comes into contact with the reducing gas passing through, and reduction takes place. The reduced gas from the reduced residue is discharged from the exhaust port 21.
is discharged to the outside. When the layered metal powder 19 is heated to a constant temperature from the supply zone 15 to the heating zone 16, the metal powders 19 sinter together and become cake-like, losing fluidity. One layered metal powder that has lost fluidity is one steel mesh belt? Less likely to fall. Further, the reducing gas supplied from the inlet 27 crosses the steel mesh belt 12 and the layered metal powder 19 through the opening 22 of the holder 211 of the belt 12, and then is discharged through the outlet 21.

保持具２４の両側には炉壁より突出板２６が設けである
ので、還元ガスは１００％層状金属粉末１９と接触する
。さらに、加熱域１６に続く冷却域１７の炉壁上部２８
は、加熱域１６より低くしであるので、還元ガスは加熱
域１６から供給域１５Ｋかけてのみ流通させることがで
き、還元ガスを節約できろ。Since plates 26 protruding from the furnace wall are provided on both sides of the holder 24, 100% of the reducing gas comes into contact with the layered metal powder 19. Furthermore, the upper part 28 of the furnace wall of the cooling zone 17 following the heating zone 16
Since it is lower than the heating zone 16, the reducing gas can be passed only from the heating zone 16 to the supply zone 15K, which can save reducing gas.

加熱域１６を出たケーキ状の層状金属粉末１９は。The cake-like layered metal powder 19 exits the heating zone 16.

ベルト１２の走行により冷却域１７に移行され冷却され
た後、搬出される。この冷却域１７は、炉壁下部２８と
下部２９が加熱域１６より狭くなっているので。After being moved to the cooling area 17 and cooled by the running of the belt 12, it is carried out. This cooling zone 17 is narrower than the heating zone 16 at the lower part 28 and lower part 29 of the furnace wall.

高温ガスが入り込むことがなく、効率よい冷却ができる
。High-temperature gas does not enter, allowing efficient cooling.

以下にこの発明の実施例及び比較例を記す。Examples and comparative examples of the present invention are described below.

実施例（１＞−１ 被還元金属粉末として水素還元減量が１ｂ％の粉末冶金
用噴霧純鉄粉を用い、アンモニア分解ガス（凡＋５　Ｈ
ａ　）雰囲気中で９００℃の温度で水素還元量を０２％
になるまで還元した。但し、ベルトの積載厚さ９時間当
りの還元量は同一とした。Example (1>-1 Atomized pure iron powder for powder metallurgy with hydrogen reduction loss of 1b% was used as the metal powder to be reduced, and ammonia decomposition gas (approximately +5 H
a) Reduce the amount of hydrogen reduction by 0.2% at a temperature of 900°C in an atmosphere
I returned it until it became. However, the amount of reduction per 9 hours of belt loading thickness was the same.

この還元結果を従来法と比較して表１に示す。The results of this reduction are shown in Table 1 in comparison with the conventional method.

表　　　　　１ 還元ガス効率は５倍以上、ガス消費量は７０％の低減が
はかれた。なお、上述鉄粉の同条件での理論的な還元ガ
ス効率は、熱力学的に推定すると約＾島であり１本発明
法によれば、この理論値に大きく近づいている。Table 1 Reducing gas efficiency was increased by more than 5 times, and gas consumption was reduced by 70%. Note that the theoretical reducing gas efficiency of the above-mentioned iron powder under the same conditions is estimated thermodynamically to be about ^^, and according to the method of the present invention, it approaches this theoretical value greatly.

実施例（１）−２ 消費ガス量の低減に伴い、アンモニア分解ガスの分解エ
ネルギー及び還元炉内での再昇温エネルギーの低減効果
を表１番こ示す。Example (1)-2 Table 1 shows the effect of reducing the decomposition energy of ammonia decomposition gas and the reheating energy in the reduction furnace due to the reduction in the amount of gas consumed.

表　　　　　ｌ 上表かられかるように本発明法によれば、エネルギー費
（％の低減を達成できた。Table l As can be seen from the above table, according to the method of the present invention, a reduction in energy costs (%) was achieved.

また、実施例（１）−１，２を併せて考えると１本発明
によ外還元工程でのランニングコストは、還元性ガスの
原料費及び分解、再分解エネルギーを加算すると従来法
の約騒に低減することが判明している。In addition, considering Example (1)-1 and 2 together, it can be seen that the running cost of the external reduction process according to the present invention is about the same as that of the conventional method when the raw material cost of the reducing gas and the decomposition and re-decomposition energy are added. It has been found that this decreases to

実施例（２） 粉末冶金用鉄粉として重要な品質の指標となる還元後の
水素還元減量の平均値、ＷＡ準偏差を前記鉄粉の全体、
上部、下部でとった値を従来法と比較して表置に示す。Example (2) The average value of hydrogen reduction loss after reduction, which is an important quality indicator for iron powder for powder metallurgy, and the WA standard deviation of the entire iron powder,
The values taken at the top and bottom are shown in the table for comparison with the conventional method.

なお、サンプルの採取は全体が還元、粉砕後に全体から
縮分して採取、上部が還元後の鉄粉層上部５關以内で採
取、下部が還元後の鉄粉層下部５−以内で採取したもの
である。In addition, the sample was collected as a whole after reduction, the whole was reduced after being crushed, the upper part was collected within 5 degrees of the upper part of the iron powder layer after reduction, and the lower part was collected within 5 degrees of the lower part of the iron powder layer after reduction. It is something.

表　　　　　ｌ このように本発明法によれば、水素還元減量のロフト内
でのばらつきが減少して鉄粉の品質が向上し、ロフト間
のばらつきも少なくなり品質が安定した。Table 1 As described above, according to the method of the present invention, the variation in hydrogen reduction weight loss within a loft was reduced, improving the quality of iron powder, and the variation between lofts was also reduced, resulting in stable quality.

以上詳述したように０本発明に係る金属粉末用ベルト式
還元炉及びその操業方法によれば、還元炉に供給された
還元性ガスは、そのほとんどが層状金属粉末と交差し、
金属粉末と接触する確率が従来法に比べて極めて高いた
め、供給されたガスの還元ガス効率は飛−的に向上し、
さらに、還元性ガスは層状金属粉末の下部から完全に交
差するため還元後に層状金属粉末の上面及び下面で酸素
量に差が生ずることはなく、従来法のようにロフト内で
酸素量の異なる金属粉末が混在したり、被還元金属粉末
が酸素量のばらつきの影−を受けることは全くなく、す
なわち、還元後の金属粉末の酸素量はロフト内にてすべ
て同一であり、ロフト間のばらうきも極めて少ないとい
う効果がある。As detailed above, according to the belt-type reduction furnace for metal powder and its operating method according to the present invention, most of the reducing gas supplied to the reduction furnace intersects with the layered metal powder.
Since the probability of contact with metal powder is extremely high compared to conventional methods, the reducing gas efficiency of the supplied gas is dramatically improved.
Furthermore, since the reducing gas completely intersects from the bottom of the layered metal powder, there is no difference in the amount of oxygen between the top and bottom surfaces of the layered metal powder after reduction. There is no mixing of powders, and the metal powder to be reduced is not affected by variations in the amount of oxygen. In other words, the amount of oxygen in the metal powder after reduction is the same within each loft, and there is no difference between lofts. There is also the effect that there are very few

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

第１図は、従来の還元炉の縦断面図、ｌ！２図は本発明
の還元炉の縦断面図、第う図は、第２図の震−璽矢視図
、第ζ図は、第２図のＷ−ＩＶ矢視図。 第５図は、第２図のマーマ矢視図、そして第６図は９本
発明の保持具の斜視図である。 １２・・・ベルト、麹、　２０．２１．２８．２９・・
・炉壁、１５・・・供給域、１６・・−加熱域、　１７
・・・冷却域、１８・・・ホッパー。 １９・・・未還元金属粉末、２１・・・排出０．２１１
・・・保持具。 ２７・・・導入口 特許出願人 トヨタ自動車工業株式会社 代表者　森　１）俊　夫 ￥　／　圓 舅　２　図Figure 1 is a vertical cross-sectional view of a conventional reduction furnace, l! FIG. 2 is a longitudinal sectional view of the reduction furnace of the present invention, FIG. 5 is a view in the direction of the marma arrow in FIG. 2, and FIG. 6 is a perspective view of the holder of the present invention. 12...belt, koji, 20.21.28.29...
・Furnace wall, 15... Supply area, 16...-Heating area, 17
...cooling area, 18...hopper. 19...Unreduced metal powder, 21...Emission 0.211
...Holding tool. 27... Introductory patent applicant Toyota Motor Corporation Representative Mori 1) Toshio ￥ / Ennen 2 Figure

Claims (1)

【特許請求の範囲】 （１）未還元金属粉末を載置して連続的に移行させる無
限軌道金属製ベルトと、該ベルトの駆動装置と前記ベル
トの未還元金属粉末が載置される部分を囲繞するよう配
設された炉壁と、該炉壁に設けられる還元ガスの供給口
及び排出口と前記炉壁に設けられ未還元金属粉末を前記
ベルト上に連続的に供給するホッパーと、前配炉壁内に
設けられ前記ベルト上の未還元粉末を加熱する加熱手段
とからなり、前記ベルト上の未還元粉末を高温還元性雰
囲気にて連続的に還元するようにしｔこ金属粉末用ベル
ト式還元炉であって、前記ベルトに通気性を持たせ前記
炉壁内の中央付近において通気性を有するベルト保持具
によ吟、ベルトを支持し。 前記炉壁の下方に還元ガスの導入口若しくは排出口を設
け、前記炉壁の上方に還元ガスの排出口若しくは導入口
を設けることを特徴とする金属粉末用ベルト式還元炉 （２、特許請求の範囲第１項において、金属粉末が載置
されるベルトを炉壁土部との間の空間を供給域及び冷却
域において小さく、加熱域において大きくしたことを特
徴とする金属粉末用ベルト式（３）特許請求の範囲第２
項において、供給域及び冷却域において、下方の前記炉
譬を前記ベルトと摺接させたことを特徴とする金縛粉末
用ベルト式還元炉 （４）特許請求の範囲第１項乃至第５項において前記ベ
ルトとして金属メツシュベルトを用いたことを特徴とす
る金属粉末用ベルト式還元炉（５）未還元金属粉末をホ
ッパーからその下方の無端金属環核ベルト上に連枦的に
供給し、そのベルトの走行によって未還元金属粉末を加
熱炉に連続的に移行させ、その加熱炉に還元性ガスを導
入してベルト上の未還元粉末を高温還元雰囲気番こて連
続的に還元するようにした金属粉末用ベルト式還元炉で
あって、前記ベルトに通気性を持たせろとともに、前記
ベルトを流通するように還元ガスを炉壁内へ供給かつ排
出することを特徴とする金属粉末用ベルト式還元炉の操
業方法[Scope of Claims] (1) An endless track metal belt on which unreduced metal powder is placed and transferred continuously, a driving device for the belt, and a portion of the belt on which the unreduced metal powder is placed. a furnace wall arranged to surround a furnace wall; a reducing gas supply port and a discharge port provided in the furnace wall; a hopper provided in the furnace wall for continuously supplying unreduced metal powder onto the belt; A belt for metal powder, comprising a heating means provided in the furnace wall and heating the unreduced powder on the belt, so as to continuously reduce the unreduced powder on the belt in a high-temperature reducing atmosphere. In the reduction furnace, the belt is provided with air permeability, and the belt is supported near the center of the furnace wall by a belt holder having air permeability. A belt-type reduction furnace for metal powder (2, Patent Claims: In range 1 of the above, a belt type for metal powder (3 ) Claim 2
Claims 1 to 5 of the present invention provide a belt-type reduction furnace for bound powder, characterized in that the lower part of the furnace is in sliding contact with the belt in the supply zone and the cooling zone (4) Claims 1 to 5 (5) A belt-type reduction furnace for metal powder characterized in that a metal mesh belt is used as the belt (5) Unreduced metal powder is continuously supplied from a hopper onto an endless metal ring core belt below the hopper, and the belt The unreduced metal powder is continuously transferred to a heating furnace by the running of the belt, and a reducing gas is introduced into the heating furnace to continuously reduce the unreduced powder on the belt using a high-temperature reducing atmosphere. A belt-type reduction furnace for metal powder, characterized in that the belt has ventilation, and reducing gas is supplied and discharged into the furnace wall so as to flow through the belt. How to operate