JPH063050A - Drying method of powder material - Google Patents
Drying method of powder materialInfo
- Publication number
- JPH063050A JPH063050A JP18059192A JP18059192A JPH063050A JP H063050 A JPH063050 A JP H063050A JP 18059192 A JP18059192 A JP 18059192A JP 18059192 A JP18059192 A JP 18059192A JP H063050 A JPH063050 A JP H063050A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- heating furnace
- furnace
- drying
- core tube
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Drying Of Solid Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、粉体の高速乾燥方法に
関する。本発明の方法は、耐熱性を有する粉体を、不純
物の混入による汚染を極力少なくし、短時間内に乾燥さ
せる方法として好適である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high speed drying method for powder. INDUSTRIAL APPLICABILITY The method of the present invention is suitable as a method for drying a heat-resistant powder within a short time while minimizing contamination due to the inclusion of impurities.
【０００２】[0002]
【従来技術】湿り粉体の乾燥方法としては、１）粉体を
棚段に並べて熱風を送り、回分式または連続式で加熱す
る箱型乾燥装置を用いる方法; ２）内部に粉体掻き上げ
板を備えた傾斜回転体内に粉体を供給し、熱風で加熱す
る回転乾燥器を用いる方法;３）気流中に粉体を同伴さ
せ、燃焼ガス等で加熱して乾燥させる気流乾燥器を用い
る方法; ４）多孔板または金網上の粉体層に下方より熱
風を吹き込み、粉体を流動化させて乾燥する流動層乾燥
器を用いる方法など、各種の方法がある。これらの方法
においては、いずれも、乾燥用熱源として熱風が用いら
れる。2. Description of the Related Art As a method for drying wet powder, 1) a method of using a box-type drying device in which the powder is arranged in shelves and hot air is sent to heat it batchwise or continuously; A method of using a rotary dryer in which powder is supplied into an inclined rotary body equipped with a plate and heated by hot air; 3) An airflow dryer is used in which the powder is entrained in an air stream and heated by combustion gas or the like to dry. Method; 4) There are various methods such as a method of using a fluidized bed dryer in which hot air is blown from below to a powder layer on a perforated plate or a wire net to fluidize and dry the powder. In all of these methods, hot air is used as a heat source for drying.
【０００３】[0003]
【発明が解決しようとする課題】本発明者等は高純度シ
リカの湿り粉体を乾燥するにあたって、不純物が混入す
る機会をできるだけ小さくして高い純度を維持しなが
ら、かつ短時間内に乾燥させることができる方法につい
て研究を続けてきたが、前記１）の方法では、回分式で
行う場合には、粉体の汚染は少ないが生産性が低い。一
方、連続式で行う場合や、また２）および３）の方法で
は、いずれも粉体の移動層を形成させるために、装置の
摩耗による粉体の汚染が起こり、また、４）の方法で
は、乾燥時間の短縮化が可能であるが、粉体を流動化さ
せるために、同様に、装置の摩耗によって粉体が汚染さ
れるという問題があった。SUMMARY OF THE INVENTION The inventors of the present invention dried the wet powder of high-purity silica in a short time while keeping the high purity by minimizing the chance of impurities being mixed in. Although research has been continued on a method capable of achieving this, in the method of 1) above, when the batch method is used, powder contamination is low but productivity is low. On the other hand, in the case of the continuous method or in the methods of 2) and 3), the powder is contaminated due to the wear of the apparatus because the moving layer of the powder is formed in both methods, and in the method of 4). Although it is possible to shorten the drying time, there is a problem that the powder is contaminated due to the wear of the apparatus in order to fluidize the powder.
【０００４】また、乾燥用熱源として熱風を用いる前記
従来の方法によって高純度シリカの湿り粉体を乾燥する
際には、不純物の混入による粉体の汚染を極力少なくす
るために、熱源として清浄な熱風を使用する必要があ
る。そのため、、燃焼ガスをそのまま用いることはでき
ず、乾燥用熱源を得るのに清浄空気を加熱するための手
段が必要であり、装置が大型化すると共に、得られる加
熱空気の温度に限度があるため乾燥効率の点でも問題が
あった。このようなことから、従来の方法における問題
点を改善し、装置材料および乾燥用熱源からの粉体汚染
を極力少なくし、かつ短時間内に乾燥させることができ
る、高純度シリカ粉体の乾燥方法が求められていた。Further, when the wet powder of high-purity silica is dried by the above-mentioned conventional method using hot air as a heat source for drying, in order to minimize contamination of the powder due to mixing of impurities, a clean heat source is used. It is necessary to use hot air. Therefore, the combustion gas cannot be used as it is, a means for heating the clean air is required to obtain the heat source for drying, the apparatus becomes large, and the temperature of the obtained heated air is limited. Therefore, there was a problem in terms of drying efficiency. From the above, it is possible to improve the problems in the conventional method, to minimize the powder contamination from the equipment material and the heat source for drying, and to dry the high-purity silica powder in a short time. A method was sought.
【０００５】本発明の目的は、乾燥処理における被乾燥
粉体の汚染を極力少なくし、かつ短時間内に乾燥させる
ことができる、粉体の乾燥方法を提供することにある。An object of the present invention is to provide a powder drying method which can minimize the contamination of the powder to be dried during the drying process and can dry the powder within a short time.
【０００６】[0006]
【課題を解決するための手段】本発明者等は高純度シリ
カの湿り粉体を乾燥するにあたって、不純物が混入する
機会をできるだけ小さくして、高い純度を維持しなが
ら、かつ短時間内に乾燥させることができる方法を種々
検討した結果、加熱炉内に粉体を供給して希薄な密度の
粉体層を形成させ、該加熱炉からの放射伝熱によって粉
体を加熱することことにより、粉体を汚染させることな
く、極めて短時間に乾燥できることを知り本発明を完成
した。Means for Solving the Problems In drying the wet powder of high-purity silica, the present inventors minimize the chance of impurities being mixed in, and maintain the high purity while drying in a short time. As a result of various examinations of a method capable of controlling, a powder is supplied into the heating furnace to form a powder layer having a low density, and the powder is heated by radiative heat transfer from the heating furnace, The inventors have completed the present invention knowing that they can be dried in an extremely short time without contaminating the powder.
【０００７】本発明は、「加熱炉内において、粉体密度
が希薄な状態で、該加熱炉からの放射伝熱によって粉体
を加熱することを特徴とする粉体の乾燥方法。」を要旨
とする。The gist of the present invention is "a method for drying powder, characterized in that the powder is heated in the heating furnace by radiant heat transfer from the heating furnace while the powder density is low." And
【０００８】本発明の方法の好ましい実施態様として
は、加熱炉内における粉体密度が、加熱炉の空間容積１
ｍ3 あたり 100〜0.1 kgの範囲であることがよい。ま
た、粉体がシリカ粒子であり、加熱炉内における粉体密
度が、加熱炉の空間容積１ｍ3 あたり 100〜0.1 kgの範
囲であって、加熱炉の温度は 600〜1500℃の範囲内であ
ることがよい。また、加熱炉が石英ガラス製の炉芯管を
使用した縦型炉であり、加熱炉内に粉体を供給するにあ
たっては炉芯管の上部からシリカ粒子を自由落下させる
ことがよい。In a preferred embodiment of the method of the present invention, the powder density in the heating furnace is 1 volume of the heating furnace.
It is preferable that the range is 100 to 0.1 kg per m 3 . Further, the powder is silica particles, the powder density in the heating furnace is in the range of 100 to 0.1 kg per 1 m 3 of space volume of the heating furnace, and the temperature of the heating furnace is in the range of 600 to 1500 ° C. Good to have. Further, the heating furnace is a vertical furnace using a furnace core tube made of quartz glass, and when the powder is supplied into the heating furnace, it is preferable that silica particles fall freely from the upper part of the furnace core tube.
【０００９】以下、本発明の詳細を説明する。本発明の
方法は、シリカ、アルミナ、ジルコニア、窒化珪素、各
種セラミックスなどの耐熱性を有する粉体に適用するこ
とができる。The details of the present invention will be described below. The method of the present invention can be applied to powders having heat resistance such as silica, alumina, zirconia, silicon nitride and various ceramics.
【００１０】本発明の方法では、乾燥用熱源として熱放
射エネルギーを利用する。本発明の方法においては、湿
り粉体の個々の粒子が熱放射線を受けることが好まし
く、従って、加熱炉内における粉体密度は重要な因子で
ある。たとえば、粉体の充填層または移動層などの粉体
が堆積して粉体密度が高い層では、熱放射線が層内部の
粉体粒子まで到達せず、均一に加熱されない。The method of the present invention utilizes thermal radiant energy as a heat source for drying. In the method of the present invention, it is preferred that individual particles of the wet powder be subjected to thermal radiation, and thus the powder density in the furnace is an important factor. For example, in a layer having a high powder density due to the accumulation of powder such as a packed layer or a moving layer of powder, thermal radiation does not reach the powder particles inside the layer and is not heated uniformly.
【００１１】本発明の方法では、希薄な粉体密度が必要
であり、加熱炉内における粉体密度が、加熱炉の空間容
積１ｍ3 あたり 100〜0.1 kgの範囲であることがよい。
たとえば、平均粒径が 300μｍであるシリカ粉体の場合
には、加熱炉内の空間容積１ｍ3 あたり 100〜0.1 kg、
好ましくは１０〜0.1 kg、更に好ましくは２〜0.1 kgの
範囲とすることがよい。 100kgを超えると、熱放射線を
受けない粒子が残り易く、均一に加熱され難いので好ま
しくない。一方、0.1 kg未満では、装置効率が低く工業
的に好ましくない。The method of the present invention requires a dilute powder density, and the powder density in the heating furnace is preferably in the range of 100 to 0.1 kg per 1 m 3 of space volume of the heating furnace.
For example, in the case of silica powder having an average particle size of 300 μm, 100 to 0.1 kg per 1 m 3 of space volume in the heating furnace,
The range is preferably 10 to 0.1 kg, more preferably 2 to 0.1 kg. If it exceeds 100 kg, particles that do not receive thermal radiation tend to remain and it is difficult to uniformly heat the particles, which is not preferable. On the other hand, if it is less than 0.1 kg, the efficiency of the apparatus is low and it is not industrially preferable.
【００１２】本発明の方法において、加熱炉内において
粉体密度が希薄な状態を形成させるにあたって加熱炉内
に粉体を供給する方法としては、たとえば、加熱炉の上
部から炉内に粉体を自由落下させる方法、加熱炉の上部
から粉体を気流中に同伴させる方法、加熱炉の下部また
は／および中部から粉体を上昇気流中に同伴させる方法
などがある。これらの内、粉体を自由落下させる方法が
最も好ましい。In the method of the present invention, as a method of supplying the powder into the heating furnace in order to form a state in which the powder density is low in the heating furnace, for example, the powder is fed from the upper part of the heating furnace into the furnace. There are a method of free fall, a method of entraining powder in an air stream from the upper part of a heating furnace, a method of entraining powder in an ascending air stream from the lower part and / or the middle part of the heating furnace. Of these, the method of free-falling the powder is most preferable.
【００１３】本発明の方法においては、被乾燥粉体を熱
放射エネルギーによって加熱するため、粉体の伝熱量は
その表面積の影響を受ける。即ち、粒径が大きい粉体
は、単位質量当たりの表面積が小さいので、加熱炉の温
度条件が同じときには伝熱速度が減少する。所要の伝熱
量を確保するには、加熱炉内での滞留時間を長くするこ
とが必要となり、あるいはまた、加熱炉の長さを大きく
する必要がある。In the method of the present invention, since the powder to be dried is heated by the thermal radiation energy, the heat transfer amount of the powder is influenced by the surface area thereof. That is, since the powder having a large particle size has a small surface area per unit mass, the heat transfer rate decreases when the temperature conditions of the heating furnace are the same. In order to secure the required amount of heat transfer, it is necessary to prolong the residence time in the heating furnace, or it is necessary to increase the length of the heating furnace.
【００１４】本発明の方法においては、粉体に同伴され
る水分など液体の含有量を考慮して粉体の供給量を制御
することにより、あらゆる粒径の粉体を乾燥することが
可能であり、本発明の方法を適用できる粉体の大きさに
制限はない。しかし、湿り粉体を自由落下させる方法で
は、加熱された湿り粉体から発生する同伴液体の蒸気
が、自由落下する粉体の向きとは反対の方向、すなわ
ち、加熱炉の上端に向かって上昇するので、粉体の粒径
が小さい場合には、発生した液体蒸気の上昇流に粉体が
同伴され、効率的が乾燥が妨げられる。このようなこと
から、工業的に安定した乾燥処理を行うには、湿り粉体
の粒径には実用上制限がある。In the method of the present invention, powder having any particle size can be dried by controlling the amount of powder supplied in consideration of the content of liquid such as water entrained in the powder. There is no limitation on the size of the powder to which the method of the present invention can be applied. However, in the method of free-falling the wet powder, the vapor of the entrained liquid generated from the heated wet powder rises in the direction opposite to the direction of the free-falling powder, that is, toward the upper end of the heating furnace. Therefore, when the particle diameter of the powder is small, the powder is entrained in the generated upward flow of the liquid vapor, and the drying is effectively prevented. Therefore, the particle size of the moist powder is practically limited in order to carry out the industrially stable drying process.
【００１５】水分を同伴するシリカ粉体の場合、平均粒
径で、２０μｍないし５mmの範囲、好ましくは３０μｍ
ないし３mmの範囲がよい。平均粒径が２０μｍ未満であ
る粉体では、発生する水蒸気による粉体の同伴が起こり
易くなるために、粉体の安定した自由落下が維持でき
ず、乾燥が困難になる。一方、５mmを超える粉体では、
単位質量当たりの表面積の減少による放射伝熱量の不足
を補うため、所要の自由落下距離を確保するために加熱
炉を長くする必要があり、実用的ではない。In the case of silica powder which entrains water, the average particle size is in the range of 20 μm to 5 mm, preferably 30 μm.
A range of 3 mm is preferable. In the case of powder having an average particle size of less than 20 μm, the powder is likely to be entrained by the generated steam, so that stable free fall of the powder cannot be maintained and drying becomes difficult. On the other hand, if the powder exceeds 5 mm,
This is not practical because it is necessary to lengthen the heating furnace in order to secure the required free fall distance in order to compensate for the lack of radiant heat transfer due to the decrease in surface area per unit mass.
【００１６】また、本発明者等は、水分を同伴するシリ
カ粉体の場合、加熱炉の上部から湿り粉体を供給する際
に、加熱炉内温度を 400℃以上、好ましくは 600℃以
上、更に好ましくは 800℃以上にすることにより、特別
の分散装置を用いることなく、凝集状態で供給された湿
り粉体の加熱炉内における分散が良好であること、加熱
炉の温度が高い方が容易に分散することを見出した。湿
り粉体が凝集している場合でも、加熱炉内に入ると、同
伴されている水分が熱放射線を受けて急速に気化し膨張
することにより、凝集していた粉体粒子が分散するもの
と考えられる。この粉体粒子の分散効果は熱放射線の伝
熱速度に関係する。Further, in the case of silica powder which entrains water, the present inventors have found that when the wet powder is supplied from the upper part of the heating furnace, the temperature inside the heating furnace is 400 ° C. or higher, preferably 600 ° C. or higher, More preferably, by setting the temperature to 800 ° C or higher, it is easy to disperse the moist powder supplied in the agglomerated state in the heating furnace without using a special dispersing device, and it is easier for the heating furnace temperature to be higher. It was found to be dispersed in. Even when the wet powder is agglomerated, when it enters the heating furnace, the entrained water is rapidly vaporized and expanded by heat radiation, and the agglomerated powder particles are dispersed. Conceivable. The dispersion effect of the powder particles is related to the heat transfer rate of thermal radiation.
【００１７】本発明の方法を適用する、乾燥処理の対象
とするシリカ粉体は、その組成及び製造方法に制約され
ない。The silica powder to which the method of the present invention is applied and which is the object of the drying treatment is not restricted by its composition and production method.
【００１８】本発明の方法では乾燥用熱源として熱放射
エネルギーを利用するので、加熱炉の温度は重要であ
る。高温物体から放射される熱放射エネルギーについて
は、下記(1) の式で表される、Stefan-Boltzmannの法則
が知られている。これによると、熱放射エネルギーは絶
対温度の４乗に比例するので、放射伝熱による乾燥を行
う際に、所要の熱量の伝熱を短時間で完了させ、加熱炉
の長さを短くするためには、加熱炉の温度を高くするこ
とが好ましい。 Ｅ＝σ（Ｔ／１００）4 ‥‥‥ (1) Ｅ：熱放射エネルギー, ［kcal／ｍ2 ・ hr］ σ：Stefan-Boltzmann定数（＝ 4.88 kcal／ｍ2 ・ hr ・
°Ｋ) Ｔ：絶対温度, ［°Ｋ］The temperature of the heating furnace is important because the method of the present invention utilizes thermal radiation energy as a heat source for drying. Regarding the thermal radiation energy radiated from a high-temperature object, the Stefan-Boltzmann law, which is expressed by the equation (1) below, is known. According to this, since the thermal radiation energy is proportional to the fourth power of the absolute temperature, when drying by radiative heat transfer, the required amount of heat transfer is completed in a short time and the length of the heating furnace is shortened. Therefore, it is preferable to raise the temperature of the heating furnace. E = σ (T / 100) 4 ‥‥‥‥ (1) E: Thermal radiation energy, [kcal / m 2 · hr] σ: Stefan-Boltzmann constant (= 4.88 kcal / m 2 · hr ·
° K) T: Absolute temperature, [° K]
【００１９】しかし、耐火材、ヒーター、炉芯管等の耐
熱性と実用性を考慮すると、加熱炉の温度には工業的に
は制約がある。本発明者らは、高純度シリカの湿り粉体
を乾燥するにあたって種々検討した結果、炉材からの汚
染を防止し、かつ、伝熱を阻害しない炉芯管として、た
とえば石英ガラス管を用いた場合には、加熱炉の温度が
６００〜１５００℃の範囲、好ましくは８００〜１４０
０℃の範囲であることが、乾燥時間の短縮に適している
ことを見出した。温度が６００℃未満では、熱放射エネ
ルギーが減少するため、所要の乾燥時間が増大し、大型
の加熱炉を要する。一方、温度が１５００℃を超える
と、石英ガラスが結晶化の進行によって失透し、炉芯管
の寿命が短くなるので、工業的には適さない。However, considering the heat resistance and practicality of the refractory material, the heater, the furnace core tube, etc., the temperature of the heating furnace is industrially limited. As a result of various studies on drying the moist powder of high-purity silica, the inventors used, for example, a quartz glass tube as a furnace core tube that prevents contamination from the furnace material and does not hinder heat transfer. In this case, the temperature of the heating furnace is in the range of 600 to 1500 ° C., preferably 800 to 140.
It was found that the range of 0 ° C is suitable for shortening the drying time. When the temperature is lower than 600 ° C., the thermal radiation energy decreases, so that the required drying time increases and a large heating furnace is required. On the other hand, when the temperature exceeds 1500 ° C., the quartz glass is devitrified due to the progress of crystallization and the life of the furnace core tube is shortened, which is not industrially suitable.
【００２０】本発明の方法において、希薄な粉体密度を
保持する時間は、湿り粉体の形状、粒径、水分含有率等
に応じて適宜選定される。湿り粉体を、その乾燥が完了
するための所要の時間の間、希薄な粉体密度を保持し
て、加熱炉内に滞留させる。湿り粉体を自由落下方式で
供給する場合には、乾燥を完了させるための所要の時間
に応じて、落下の必要距離、すなわち、加熱炉の長さが
決められる。In the method of the present invention, the time for maintaining the lean powder density is appropriately selected depending on the shape, particle size, water content of the wet powder and the like. The wet powder is retained in the heating furnace while maintaining a dilute powder density for the time required to complete its drying. When the wet powder is supplied by the free fall method, the required distance of the fall, that is, the length of the heating furnace is determined according to the time required to complete the drying.
【００２１】本発明の方法により、乾燥の所要時間を２
〜３秒程度ないし１０秒以内とすることができる。According to the method of the present invention, the time required for drying is 2
It can be set to about 3 seconds to 10 seconds.
【００２２】高純度シリカの湿り粉体を乾燥処理する際
には、加熱炉内に炉芯管を用いることがよく、その材質
の選定が重要である。炉芯管として必要な性能は、シリ
カ粉体を汚染させないことと、ならびに、熱放射線を透
過させるか、もしくは、高い熱放射率を有することであ
る。湿り粉体を熱放射線で加熱して乾燥させるには、加
熱炉の熱源を含む炉材からの熱放射線を直接に湿り粉体
に照射する方法と、炉芯管を加熱して炉芯管から放射さ
れる熱放射線を利用する間接的な方法がある。前者の方
法では、熱放射線を透過させる材料として、たとえば、
石英ガラス製の管が使用できる。後者の方法では、たと
えば、アルミナセラミックスや炭化珪素製の管が使用で
きる。なお、石英ガラスとしては、透明石英ガラスが好
ましいが、気泡を含む不透明石英ガラスであっても、透
明石英ガラスと同様に熱放射線を透過させるので用いる
ことができる。When the wet powder of high-purity silica is dried, a furnace core tube is often used in the heating furnace, and the selection of its material is important. The required performance of the furnace core tube is that it does not contaminate the silica powder and that it transmits thermal radiation or has a high thermal emissivity. To heat and dry the moist powder with heat radiation, there is a method of directly irradiating the moist powder with heat radiation from the furnace material including the heat source of the heating furnace, and heating the furnace core tube to remove it from the furnace core tube. There are indirect methods that utilize the emitted thermal radiation. In the former method, as a material that transmits thermal radiation, for example,
Quartz glass tubes can be used. In the latter method, for example, a tube made of alumina ceramics or silicon carbide can be used. As the quartz glass, transparent quartz glass is preferable, but opaque quartz glass containing bubbles can be used as it transmits thermal radiation like transparent quartz glass.
【００２３】[0023]
【実施例】以下、本発明を実施例によって具体的に説明
する。 実施例１ 被乾燥粉体としての高純度シリカ粉体は、次のようにし
て調製した。ケイ酸ソーダ#3号を、孔径が 400μｍφの
ノズルを通して、温度50℃に保持した硫酸凝固浴中に押
し出し、得られた繊維状ゲルを、硫酸中に浸漬し撹拌し
ながら 100℃で１時間処理し、ヌッチェを用いて脱酸し
た。硫酸処理を繰り返し行って得られた短繊維状シリカ
を、イオン交換水を用いて洗浄・ろ過を行って脱酸・脱
水し、シリカ湿粉を得た。得られたシリカ湿粉は、 150
℃絶乾法による水分計測で含水率42重量％であって、不
純物の含有率が Na 0.2 ppm, Al 0.4 ppm, Zr 0.1 ppm
である高純度シリカであった。シリカ湿粉の粒度は、平
均粒径が 320μｍであり、粒径20μｍ以下の粒子を３重
量％含み、かつ、粒径 600μｍ以上の粒子を含まないも
のであった。EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A high-purity silica powder as a powder to be dried was prepared as follows. Sodium silicate # 3 was extruded through a nozzle with a pore size of 400 μmφ into a sulfuric acid coagulation bath maintained at a temperature of 50 ° C, and the resulting fibrous gel was immersed in sulfuric acid and treated at 100 ° C for 1 hour with stirring. Then, it was deoxidized using a Nutsche. The short fibrous silica obtained by repeating the sulfuric acid treatment was washed and filtered with ion-exchanged water to be deoxidized and dehydrated to obtain a wet silica powder. The obtained silica moist powder is 150
Moisture content measured by absolute dry method at 42 ℃ is 42% by weight, and the content of impurities is Na 0.2 ppm, Al 0.4 ppm, Zr 0.1 ppm
It was high purity silica. The wet silica powder had an average particle size of 320 μm, contained 3% by weight of particles having a particle size of 20 μm or less, and did not contain particles having a particle size of 600 μm or more.
【００２４】乾燥処理は、図１に示す加熱装置１を用い
て行った。加熱装置１を構成する縦型加熱炉２には、透
明石英ガラス製の炉芯管３が鉛直に取り付けられ、炉芯
管３の上端部と通ずる加熱炉２の上端部には排気孔４が
設けられている。炉芯管３は加熱炉２に設けられたヒー
ター５で加熱される。炉芯管３の上端部には原料供給孔
６が、また、炉芯管３の下部には受器７が、それぞれ設
けられている。The drying process was performed using the heating device 1 shown in FIG. A vertical core 3 made of transparent quartz glass is vertically attached to the vertical heating furnace 2 which constitutes the heating device 1, and an exhaust hole 4 is provided at the upper end of the heating furnace 2 communicating with the upper end of the furnace core 3. It is provided. The furnace core tube 3 is heated by a heater 5 provided in the heating furnace 2. A raw material supply hole 6 is provided at the upper end of the furnace core tube 3, and a receiver 7 is provided at the lower part of the furnace core tube 3.
【００２５】炉内温度1100℃に調節された炉芯管３内
に、前記のシリカ湿粉を、毎分 120ｇの速度で原料供給
孔６から供給し、炉芯管内を自由落下させた。加熱炉内
における粉体密度は、加熱炉の空間容積１ｍ3 あたり平
均値として 1.1kgであった。供給されたシリカ粉体は、
炉芯管内を平均４秒間で自由落下し、受器７に回収され
た。回収されたシリカ粉体は、 150℃絶乾法により水分
を計測したところ、重量減少は認められなかった。ま
た、上記回収シリカ粉体 200.0ｇを石英ビーカーに入
れ、箱型の大気雰囲気電気炉内で1100℃で５時間加熱し
た後の粉体重量は 199.7ｇであった。1100℃絶乾法によ
っても、重量減少は僅かであり、含水率は殆どゼロにな
ったことが確認された。そのかさ密度は0.31ｇ／cm3 で
あった。回収されたシリカ粉体は、不純物含有率が Na
0.2 ppm, Al 0.4 ppm, Zr 0.1ppm であって、処理によ
る不純物の増大は認められず、高純度が維持された。The above silica wet powder was fed into the furnace core tube 3 adjusted to a furnace temperature of 1100 ° C. at a rate of 120 g / min from the raw material supply hole 6 and allowed to fall freely inside the furnace core tube. The powder density in the heating furnace was 1.1 kg as an average value per 1 m 3 of space volume of the heating furnace. The silica powder supplied is
It freely dropped in the furnace core tube for 4 seconds on average and was collected in the receiver 7. When the moisture content of the recovered silica powder was measured by the 150 ° C absolute drying method, no weight reduction was observed. Further, 200.0 g of the recovered silica powder was put into a quartz beaker and heated at 1100 ° C. for 5 hours in a box-type air atmosphere electric furnace, and the powder weight was 199.7 g. It was confirmed that the weight loss was small and the water content became almost zero even by the 1100 ° C absolute drying method. Its bulk density was 0.31 g / cm 3 . The recovered silica powder has an impurity content of Na
The contents were 0.2 ppm, Al 0.4 ppm, and Zr 0.1 ppm, and the impurities were not increased by the treatment, and high purity was maintained.
【００２６】実施例２ 炉芯管として透明石英ガラスの代わりに不透明石英ガラ
スを用いたほかは実施例１と同様にして、シリカ湿粉を
乾燥処理した。回収されたシリカ粉体は、実施例１と同
様にして、1100℃で５時間加熱したところ、粉体重量は
199.0ｇであって重量減少は僅かであり、含水率は殆ど
ゼロになったことが確認された。かさ密度は0.31ｇ／cm
3 であった。回収されたシリカ粉体は、不純物含有率が
Na 0.2 ppm, Al 0.4 ppm, Zr 0.1ppm であって、処理
による不純物の増大は認められず、高純度が維持され
た。Example 2 The wet silica powder was dried in the same manner as in Example 1 except that opaque quartz glass was used as the furnace core tube instead of transparent quartz glass. The recovered silica powder was heated at 1100 ° C. for 5 hours in the same manner as in Example 1, and the powder weight was
It was 199.0 g, the weight loss was slight, and it was confirmed that the water content became almost zero. Bulk density is 0.31 g / cm
Was 3 . The recovered silica powder has a high impurity content.
Na 0.2 ppm, Al 0.4 ppm, Zr 0.1 ppm, no increase in impurities due to treatment was observed, and high purity was maintained.
【００２７】[0027]
【発明の効果】本発明の方法により、不純物の混入によ
る被乾燥粉体の汚染を防ぎ、しかも、所要時間２〜３秒
程度ないし１０秒以内の極めて短時間に乾燥させること
ができる。炉芯管として石英ガラス管を用いることによ
り、高純度シリカ湿粉を汚染させることなく乾燥するこ
とができ、本発明の工業的価値は極めて大きい。According to the method of the present invention, it is possible to prevent the powder to be dried from being contaminated due to the inclusion of impurities, and to dry the powder in a very short time of about 2 to 3 seconds to 10 seconds. By using the quartz glass tube as the furnace core tube, the high-purity silica wet powder can be dried without being contaminated, and the industrial value of the present invention is extremely large.
【００２８】[0028]
【図１】図１は、本発明の実施に好適な加熱装置の一例
を示す説明図である。FIG. 1 is an explanatory view showing an example of a heating device suitable for carrying out the present invention.
【００２９】[0029]
１‥加熱装置、２‥縦型加熱炉、３‥炉芯管、４‥排気
孔、５‥ヒーター、６‥原料供給孔、７‥受器。1 ... Heating device, 2 ... Vertical heating furnace, 3 ... Furnace core tube, 4 ... Exhaust hole, 5 ... Heater, 6 ... Raw material supply hole, 7 ... Receiver.
Claims (4)
で、該加熱炉からの放射伝熱によって粉体を加熱するこ
とを特徴とする粉体の乾燥方法。1. A method of drying powder, characterized in that the powder is heated in a heating furnace by radiant heat transfer from the heating furnace while the powder density is low.
の空間容積１ｍ3 あたり 100〜0.1 kgの範囲である、請
求項１記載の粉体の乾燥方法。2. The method for drying powder according to claim 1, wherein the powder density in the heating furnace is in the range of 100 to 0.1 kg per 1 m 3 of space volume of the heating furnace.
る粉体密度が加熱炉の空間容積１ｍ3 あたり 100〜0.1
kgの範囲であり、前記加熱炉の温度が６００〜１５００
℃の範囲内である請求項１記載の粉体の乾燥方法。3. The powder is silica particles, and the powder density in the heating furnace is 100 to 0.1 per 1 m 3 of space volume of the heating furnace.
It is in the range of kg, and the temperature of the heating furnace is 600 to 1500.
The method for drying powder according to claim 1, which is in the range of ° C.
した縦型炉であり、加熱炉内に粉体を供給するにあたり
炉芯管の上部からシリカ粒子を自由落下させる請求項１
または請求項３記載の粉体の乾燥方法。4. The heating furnace is a vertical furnace using a quartz glass furnace core tube, and when supplying the powder into the heating furnace, silica particles are allowed to fall freely from the upper part of the furnace core tube.
Alternatively, the method for drying powder according to claim 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18059192A JPH063050A (en) | 1992-06-16 | 1992-06-16 | Drying method of powder material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18059192A JPH063050A (en) | 1992-06-16 | 1992-06-16 | Drying method of powder material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH063050A true JPH063050A (en) | 1994-01-11 |
Family
ID=16085945
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18059192A Pending JPH063050A (en) | 1992-06-16 | 1992-06-16 | Drying method of powder material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH063050A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006135042A1 (en) * | 2005-06-16 | 2006-12-21 | Tokai Konetsu Kogyo Co., Ltd. | Vertical firing furnace and firing method using it |
| FR2910777A1 (en) * | 2006-12-21 | 2008-06-27 | Revtech Soc Responsabilite Lim | Powdery product i.e. powder, treating method for use in e.g. chemical industry, involves heating products until specific temperature by circulation of products in tube arranged with respect to plane, where products flow in tube by gravity |
| JP2010209412A (en) * | 2009-03-10 | 2010-09-24 | Asahi Pretec Corp | Method for producing noble metal powder |
| US9769991B2 (en) | 2007-08-21 | 2017-09-26 | Suntory Holdings Limited | Planting container |
| US10806107B2 (en) | 2015-05-13 | 2020-10-20 | Hyochan JUN | Water culture block and water culture device having same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5217674A (en) * | 1975-08-01 | 1977-02-09 | Hitachi Ltd | Vacuum breaker |
-
1992
- 1992-06-16 JP JP18059192A patent/JPH063050A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5217674A (en) * | 1975-08-01 | 1977-02-09 | Hitachi Ltd | Vacuum breaker |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006135042A1 (en) * | 2005-06-16 | 2006-12-21 | Tokai Konetsu Kogyo Co., Ltd. | Vertical firing furnace and firing method using it |
| JPWO2006135042A1 (en) * | 2005-06-16 | 2009-01-08 | 東海高熱工業株式会社 | Vertical firing furnace and firing method using the same |
| FR2910777A1 (en) * | 2006-12-21 | 2008-06-27 | Revtech Soc Responsabilite Lim | Powdery product i.e. powder, treating method for use in e.g. chemical industry, involves heating products until specific temperature by circulation of products in tube arranged with respect to plane, where products flow in tube by gravity |
| WO2008081123A1 (en) * | 2006-12-21 | 2008-07-10 | Revtech | Method for the thermal treatment of powdery materials |
| US9769991B2 (en) | 2007-08-21 | 2017-09-26 | Suntory Holdings Limited | Planting container |
| JP2010209412A (en) * | 2009-03-10 | 2010-09-24 | Asahi Pretec Corp | Method for producing noble metal powder |
| US10806107B2 (en) | 2015-05-13 | 2020-10-20 | Hyochan JUN | Water culture block and water culture device having same |
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