JP2541019B2 - Method for producing silicon nitride powder - Google Patents
Method for producing silicon nitride powderInfo
- Publication number
- JP2541019B2 JP2541019B2 JP3021649A JP2164991A JP2541019B2 JP 2541019 B2 JP2541019 B2 JP 2541019B2 JP 3021649 A JP3021649 A JP 3021649A JP 2164991 A JP2164991 A JP 2164991A JP 2541019 B2 JP2541019 B2 JP 2541019B2
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- fluidized bed
- powder
- silicon
- reaction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、金属ケイ素微粉末を高
窒化率で窒化することができる窒化ケイ素粉末の製造方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing silicon nitride powder capable of nitriding metallic silicon fine powder at a high nitriding rate.
【０００２】[0002]
【従来の技術】従来、金属ケイ素を直接窒化して窒化ケ
イ素粉末を工業的に製造する方法の一つとして、流動層
を用いる方法が知られている。この方法は金属ケイ素粉
末と反応ガスとで流動層を形成させ、加熱するものであ
るが、かかる流動層反応型式の窒化ケイ素粉末の製造方
法においては、原料の金属ケイ素粉末が直接高温雰囲気
に晒されるため、流動層に投入された金属ケイ素粉末は
直ちに溶融し、粒子間同士で融着，凝集し、その結果比
表面積が減少し、反応速度が著しく低下したりして、流
動層を形成することが困難となるといった問題点を有す
る。この場合、流動層の温度を低くすると窒化反応速度
が著しく小さくなる。2. Description of the Related Art Conventionally, a method using a fluidized bed is known as one of the methods for industrially producing silicon nitride powder by directly nitriding metallic silicon. In this method, a fluidized bed is formed with metallic silicon powder and a reaction gas and heated, but in the method for producing a fluidized bed reaction type silicon nitride powder, the metallic silicon powder as a raw material is directly exposed to a high temperature atmosphere. Therefore, the metal silicon powder put into the fluidized bed is immediately melted, and the particles are fused and agglomerated with each other, resulting in a decrease in specific surface area and a significant decrease in reaction rate to form a fluidized bed. There is a problem that it becomes difficult. In this case, if the temperature of the fluidized bed is lowered, the nitriding reaction rate will be significantly reduced.
【０００３】そこで、従来このような問題点を解決する
ために金属ケイ素粉末と反応ガスとで流動層を形成さ
せ、これを加熱する際、その昇温速度を３０〜１５０℃
／Ｈｒに制御して金属ケイ素粉末の溶融，凝集を防ぎ、
品質の安定した窒化ケイ素粉末を得る方法（特開昭６１
−９７１１０号公報）が提案されているが、この方法は
炉の昇温，冷却に長時間を要するため、生産性に劣るも
のである。Therefore, in order to solve the above-mentioned problems, a fluidized bed is conventionally formed with metallic silicon powder and a reaction gas, and when heating the fluidized bed, the temperature rising rate is 30 to 150 ° C.
/ Hr is controlled to prevent melting and agglomeration of metallic silicon powder,
Method for obtaining silicon nitride powder with stable quality
However, this method is inferior in productivity because it takes a long time to heat up and cool the furnace.
【０００４】[0004]
【発明が解決しようとする課題】上記従来の製造方法の
問題点を解消した方法として、本出願人によって先に提
案された窒化ケイ素粉末を流動層方式で製造する改良方
法（特開平１−１９５９５４号）がある。この製造方法
は、金属ケイ素粉末を好ましくは粒径１４９μｍ〜４ｍ
ｍ程度に造粒し、これを、窒化ケイ素粉末と窒素ガス又
はアンモニアガスを含む非酸化性反応ガスで形成され、
かつ温度を１０００〜１４００℃に保持した第１流動層
中に連続的に供給し、該第１流動層で第１次窒化反応を
行った後、この第１流動層から窒化生成物を連続的に取
り出すと共に、これを更に窒化ケイ素粉末と窒素ガスま
たはアンモニアガスを含む非酸化性反応ガスとから形成
された第２流動層に供給し、該第２流動層で未反応の窒
化原料を窒化する第２次窒化反応を行うものであり、こ
の方法によればα相率等の品質のバラツキが少ない窒化
ケイ素粉末を安定的にかつ効率的に製造することができ
るものである。As a method for solving the problems of the above-mentioned conventional manufacturing method, an improved method for manufacturing silicon nitride powder previously proposed by the present applicant by a fluidized bed method (Japanese Patent Laid-Open No. 1-195954). No.) In this manufacturing method, the metal silicon powder preferably has a particle size of 149 μm to 4 m.
granulated to about m and formed with silicon nitride powder and a non-oxidizing reaction gas containing nitrogen gas or ammonia gas,
Further, after continuously supplying into the first fluidized bed whose temperature is maintained at 1000 to 1400 ° C. and performing the primary nitriding reaction in the first fluidized bed, the nitriding product is continuously supplied from the first fluidized bed. And then supply this to a second fluidized bed formed from silicon nitride powder and a non-oxidizing reaction gas containing nitrogen gas or ammonia gas, and nitriding the unreacted nitriding raw material in the second fluidized bed. The second nitriding reaction is performed, and according to this method, it is possible to stably and efficiently produce a silicon nitride powder with little variation in quality such as α phase ratio.
【０００５】しかしながら、上記先願方法は、金属ケイ
素粉末を造粒することを推奨しており、このように金属
ケイ素を予め造粒する理由としては、 （１）流動層内で良好な流動状態を維持すること、 （２）金属ケイ素の溶融による表面積の減少防止及び流
動層内での閉塞を防止すること、が挙げられるが、流動
層を用いて行われる当該反応の一般的な形が、流動ガス
である窒素ガスまたはアンモニアガスと金属ケイ素との
気−固系反応であることを考えると、原料である金属ケ
イ素粉末の粒子径を小さくして比表面積を大きくした方
が反応率を向上させる上で好ましい。また、気−固系反
応で得られる窒化ケイ素は、最終的にはサブミクロンオ
ーダーの適切な分布を有した粒度に粉砕する必要がある
ことからも金属ケイ素粒子は細かい方が望ましい。原料
である金属ケイ素は工業的に得られる粉砕設備を利用し
て極力微粉砕化されるが、通常、経済的に得られる微粒
子の大きさは、ＢＥＴ比表面積が４ｍ2／ｇ，平均粒子
径が１〜４４μｍ程度である。However, the above-mentioned prior application method recommends granulating the metallic silicon powder, and the reasons for preliminarily granulating the metallic silicon in this way are as follows: (1) good fluid state in the fluidized bed (2) prevention of surface area reduction due to melting of metallic silicon and prevention of clogging in the fluidized bed, but the general form of the reaction carried out using the fluidized bed is Considering that it is a gas-solid system reaction of nitrogen gas or ammonia gas which is a flowing gas and metal silicon, the reaction rate is improved when the particle size of the metal silicon powder which is the raw material is made small and the specific surface area is made large. It is preferable for the purpose. Further, since silicon nitride obtained by the gas-solid reaction must be pulverized to a particle size having an appropriate distribution on the order of submicrons, finer metal silicon particles are desirable. Metallic silicon, which is a raw material, is finely pulverized as much as possible by using industrially obtained pulverizing equipment. Usually, the size of economically obtained fine particles is as follows: BET specific surface area of 4 m 2 / g, average particle diameter. Is about 1 to 44 μm.
【０００６】従って、このように微細な金属ケイ素粉末
をそのまま用いて効率よく窒化ケイ素粉末を製造するこ
とが望まれる。Therefore, it is desired to efficiently produce silicon nitride powder by using such fine metal silicon powder as it is.
【０００７】本発明は上記要望に応えるためになされた
もので、平均粒径１５０μｍ以下、特に５０μｍ以下の
微細な金属ケイ素をそのまま効率よく直接窒化すること
ができ、金属ケイ素の高窒化率を達成し得ると共に、経
済的にも有利な窒化ケイ素粉末の製造方法を提供するこ
とを目的とする。The present invention has been made in order to meet the above demands, and it is possible to directly and directly nitrate fine metal silicon particles having an average particle diameter of 150 μm or less, particularly 50 μm or less, and achieve a high nitriding rate of metal silicon. It is an object of the present invention to provide a method for producing a silicon nitride powder which is capable of performing and is economically advantageous.
【０００８】[0008]
【課題を解決するための手段及び作用】本発明者らは、
上記目的を達成するため鋭意検討を行った結果、予め平
均粒子径５０〜１０００μｍの種窒化ケイ素粉末と窒素
又はアンモニアを含む非酸化性ガスとから流動層を形成
させておき、この流動層に原料の平均粒子径が１５０μ
ｍ以下、特に５０μｍ以下の金属ケイ素粉末を窒素又は
アンモニアを含む非酸化性ガスに同伴・分散させる等し
て連続的に当該流動層に導入し、窒化ケイ素を製造する
と共に、窒化ケイ素を排ガスに同伴させて連続的に排出
させることにより、上記微細金属ケイ素粉末をそのまま
用いて高窒化率で安価に窒化ケイ素粉末を製造できるこ
とを見い出した。Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, a fluidized bed was previously formed from a seed silicon nitride powder having an average particle diameter of 50 to 1000 μm and a non-oxidizing gas containing nitrogen or ammonia, and the raw material was formed in the fluidized bed. Average particle size of 150μ
m or less, particularly 50 μm or less, of metallic silicon powder is continuously introduced into the fluidized bed by entraining / dispersing it in a non-oxidizing gas containing nitrogen or ammonia to produce silicon nitride, and silicon nitride is used as exhaust gas. It has been found that the fine metal silicon powder can be used as it is to produce the silicon nitride powder at a high nitriding rate and at a low cost by entraining it and continuously discharging it.
【０００９】即ち、流動層反応型式による窒化ケイ素粉
末の製造方法においては、工業的に得られる粒度の金属
ケイ素の微粉末はその粒子間力が強いためそのままでは
チャネリング等を起こし、工業的に均一で良好な流動層
を維持させることが困難である。また一般に、流動層は
流動粒子の密度や粒子径及び粒度分布により、その流動
状態が異なる。例えば、Ｇｅｌｄａｒｔの分類「Ｐｏｗ
ｄｅｒ Ｔｅｃｈｎｏｌｏｇｙ，７，２８５（１９７
３）；１９，１３３（１９７８）」によると、平均粒子
径５０〜１００μｍ，粒子密度１〜２ｇ／ｃｍ3の
「Ａ」粒子は、良好な流動層を形成するために適してお
り、更に、「ｇｏｏｄ ｆｒａｃｔｉｏｎ」と呼ばれる
粒子径４４μｍ以下の粒子が適当量含まれた「Ａ’」粒
子は、特に良好な流動層を形成するために適した粒子で
あるといわれている。この分類によると、前述の工業的
に得られる粉砕された平均粒子径１〜４４μｍの金属ケ
イ素の粒子は「Ｃ」粒子に属する。「Ｃ」粒子は粒子間
力が強く作用するため、流動層内ではチャネリング等を
引き起こし、良好な流動状態を形成させることが極めて
困難であるといわれている。That is, in the method for producing silicon nitride powder by the fluidized bed reaction type, fine particles of metallic silicon of industrially obtained particle size cause channeling and the like as they are because the inter-particle force is strong, so that they are industrially uniform. It is difficult to maintain a good fluidized bed. Further, in general, the fluidized state of the fluidized bed varies depending on the density, particle size and particle size distribution of fluidized particles. For example, the Geldart classification “Pow
der Technology, 7, 285 (197)
3); 19, 133 (1978) ”, the“ A ”particles having an average particle size of 50 to 100 μm and a particle density of 1 to 2 g / cm 3 are suitable for forming a good fluidized bed, and further, It is said that "A '" particles, which are called "good fractions" and which contain an appropriate amount of particles having a particle diameter of 44 µm or less, are particles suitable for forming a particularly good fluidized bed. According to this classification, the industrially obtained particles of ground metal silicon having an average particle size of 1 to 44 μm belong to “C” particles. It is said that it is extremely difficult to form a favorable fluidized state by causing channeling or the like in the fluidized bed because the inter-particle force of “C” particles acts strongly.
【００１０】一方、ほぼ常圧における金属ケイ素の窒化
反応の開始温度は１２００℃付近であり、金属ケイ素の
溶融温度は１３００〜１４００℃と考えられている。金
属ケイ素を窒素やアンモニアガスで窒化する気−固系反
応においては、表面から窒化が始まり、内部への窒素拡
散により窒化反応が進行する。この反応は１４０〜１８
０ｋｃａｌ／モルという多量の熱が発生する発熱反応で
あり、除熱がスムーズに行われることが非常に重要であ
る。なぜなら、窒化反応が均一に進行して金属ケイ素の
表面に窒化ケイ素の膜が形成される以前に金属ケイ素が
溶融温度に到達すると、金属ケイ素粒子間の溶融・合体
が発生し、比表面積が激減すると共に、流動層の閉塞と
いう事態に到達し、もはや窒化反応を継続させることが
できなくなるからである。On the other hand, the starting temperature of the nitriding reaction of metallic silicon at about normal pressure is around 1200 ° C., and the melting temperature of metallic silicon is considered to be 1300 to 1400 ° C. In the gas-solid system reaction of nitriding metallic silicon with nitrogen or ammonia gas, nitriding starts from the surface and the nitriding reaction proceeds due to nitrogen diffusion into the inside. This reaction is 140-18
This is an exothermic reaction in which a large amount of heat of 0 kcal / mol is generated, and it is very important that heat removal is smoothly performed. This is because if the silicon metal reaches the melting temperature before the nitriding reaction proceeds uniformly and the silicon nitride film is formed on the surface of the silicon metal, the metal silicon particles will melt and coalesce, resulting in a drastic decrease in the specific surface area. In addition, the situation of blocking the fluidized bed is reached, and the nitriding reaction can no longer be continued.
【００１１】本発明は、予め平均粒子径５０〜１０００
μｍの種窒化ケイ素粉末で流動層を形成させ、これに平
均粒子径が１５０μｍ以下の金属ケイ素微粉末を窒素又
はアンモニアを含む非酸化性ガスに同伴・分散させる等
して連続的に流動層内に導入することにより、均一な流
動層を形成させることが困難な粒度の金属ケイ素を流動
粒子として用いて金属ケイ素の良好な流動層を形成させ
ることができ、金属ケイ素微粉末の凝集・粗大化が防止
され、窒化反応が進行すること、また、金属ケイ素微粉
末を種窒化ケイ素粉末に付着・成長させて窒化せしめる
と共に、窒化により得られた窒化ケイ素を排ガスに同伴
させて連続的に排出させることにより、金属ケイ素粉末
を予め造粒，乾燥，か焼するという前処理工程を行う必
要がなく、平均粒子径が５０μｍ以下という上記「Ｃ」
粒子に分類される金属ケイ素粉末を用いても、流動層の
良好な流動状態を保たせることができて、流動層反応を
用いることのコストメリットが増大し、比表面積が大き
く、平均粒子径の小さい金属ケイ素粉末をそのまま使用
して高い反応速度で効率よく窒化ケイ素粉末を得ること
ができることを知見し、本発明をなすに至った。In the present invention, the average particle size is 50 to 1000 in advance.
In a fluidized bed, a fluidized bed is formed from a seed silicon nitride powder of μm, and a fine powder of metallic silicon having an average particle diameter of 150 μm or less is entrained and dispersed in a non-oxidizing gas containing nitrogen or ammonia. Introduced into the above, it is possible to form a good fluidized bed of metallic silicon by using metallic silicon of a particle size that is difficult to form a uniform fluidized bed as fluidized particles, and to agglomerate and coarsen the metallic silicon fine powder. Is prevented, the nitriding reaction proceeds, and the metal silicon fine powder is made to adhere to and grow on the seed silicon nitride powder for nitriding, and the silicon nitride obtained by nitriding is entrained in the exhaust gas and continuously discharged. As a result, there is no need to perform a pretreatment step of granulating, drying and calcining the metallic silicon powder in advance, and the above-mentioned “C” having an average particle diameter of 50 μm or less
Even if a metal silicon powder classified into particles is used, a good fluidized state of the fluidized bed can be maintained, the cost merit of using the fluidized bed reaction is increased, the specific surface area is large, and the average particle size The inventors have found that it is possible to efficiently obtain a silicon nitride powder at a high reaction rate by using a small metal silicon powder as it is, and have completed the present invention.
【００１２】従って、本発明は、反応開始時に予め平均
粒子径５０〜１０００μｍの種窒化ケイ素粉末を窒素又
はアンモニアを含む非酸化性ガスとから流動層を形成さ
せ、該流動層中に平均粒子径１５０μｍ以下の金属ケイ
素微粉末を連続的に供給し、該金属ケイ素微粉末を窒化
して窒化ケイ素を得ると共に、該窒化ケイ素を連続的に
排出させて窒化ケイ素粉末を得ることを特徴とする窒化
ケイ素粉末の製造方法を提供するものである。Therefore, according to the present invention, at the start of the reaction, a seed bed of silicon nitride having an average particle size of 50 to 1000 μm is previously formed with a non-oxidizing gas containing nitrogen or ammonia to form a fluidized bed, and the average particle size is contained in the fluidized bed. Metallic silicon fine powder having a particle size of 150 μm or less is continuously supplied, the silicon nitride fine powder is nitrided to obtain silicon nitride, and the silicon nitride is continuously discharged to obtain silicon nitride powder. A method for producing silicon powder is provided.
【００１３】以下、本発明につき更に詳しく説明する
と、本発明で用いる種窒化ケイ素粉末の平均粒子径は５
０〜１０００μｍであり、特に２００〜５００μｍとす
ることが好ましい。平均粒子径が５０μｍ未満の場合、
チャネリング等のため流動層は、良好な流動状態を維持
することが難しく、一方、平均粒子径が１０００μｍを
超えると、流動開始速度が大きくなるため、ガス流速の
増大と共に気泡径が増大してスラッギングを起こし、５
０μｍ未満の場合と同様に良好な流動状態を維持するこ
とが困難となる。なお、種窒化ケイ素粉末は成長・破壊
を繰り返すことで、流動層内に常に５０〜１０００μｍ
の平均粒子径で存在することができる。The present invention will be described in more detail below. The seed silicon nitride powder used in the present invention has an average particle size of 5
It is 0 to 1000 μm, and particularly preferably 200 to 500 μm. When the average particle size is less than 50 μm,
It is difficult to maintain a good fluidized state in the fluidized bed due to channeling or the like. On the other hand, when the average particle diameter exceeds 1000 μm, the flow initiation speed increases, and the bubble diameter increases as the gas flow velocity increases, resulting in slugging. Cause 5
As in the case of less than 0 μm, it becomes difficult to maintain a good flow state. It should be noted that the seed silicon nitride powder is constantly grown and destroyed so that it is always 50 to 1000 μm in the fluidized bed.
Can have an average particle size of
【００１４】本発明は、上記種窒化ケイ素粉末を用いて
これを非酸化性ガスを用いて反応開始前に予め流動層を
形成する。この場合、流動層の形成は常法によって行う
ことができ、種窒化ケイ素粉末を流動させながら昇温す
ることが好ましい。In the present invention, the above-mentioned seed silicon nitride powder is used to form a fluidized bed in advance by using a non-oxidizing gas before starting the reaction. In this case, the fluidized bed can be formed by a conventional method, and it is preferable to raise the temperature while flowing the seed silicon nitride powder.
【００１５】なお、非酸化性ガスは窒化またはアンモニ
アを含むものであるが、必要によりＡｒ，Ｈｅ等の不活
性ガス或いはＨ2等の非酸化性ガス等のガスを混合して
もよい。この場合、非酸化性ガス中の窒素またはアンモ
ニア濃度は２０〜１００容量％、特に５０〜１００容量
％とすることが好ましい。Although the non-oxidizing gas contains nitriding or ammonia, an inert gas such as Ar or He or a gas such as a non-oxidizing gas such as H 2 may be mixed if necessary. In this case, the concentration of nitrogen or ammonia in the non-oxidizing gas is preferably 20 to 100% by volume, particularly 50 to 100% by volume.
【００１６】次に、本発明は、上記流動層中に金属ケイ
素粉末を連続的に供給し、該流動層中で窒化反応を行
い、金属ケイ素粉末を窒化ケイ素粉末に転化する。ここ
で、金属ケイ素微粉末の平均粒子径は１５０μｍ以下で
あり、特に１〜４４μｍとすることが好ましい。平均粒
子径が１５０μｍを超えると窒化反応の進行が妨げられ
る場合がある。また、金属ケイ素の比表面積は大きいこ
とが望まれるが、粉砕にコストがかかりすぎるため、１
〜１５ｍ2／ｇ、特に１〜４ｍ2／ｇとすることが好まし
い。金属ケイ素は造粒された粒子ではなく、通常の粉砕
機で得られる微粒子を用いることにより、金属ケイ素の
比表面積は著しく増加することになり、実質的に反応速
度を大幅に向上させることができる。上記金属ケイ素微
粉末の供給量は、種窒化ケイ素粉末１００ｇに対し１〜
１００ｇ／Ｈｒ、特に１０〜５０ｇ／Ｈｒとすることが
好ましい。Next, in the present invention, metallic silicon powder is continuously supplied into the fluidized bed, and a nitriding reaction is performed in the fluidized bed to convert the metallic silicon powder into silicon nitride powder. Here, the average particle diameter of the metallic silicon fine powder is 150 μm or less, and particularly preferably 1 to 44 μm. If the average particle size exceeds 150 μm, the progress of the nitriding reaction may be hindered. Further, it is desired that the specific surface area of the metal silicon is large, but since the crushing is too expensive, 1
It is preferably -15 m 2 / g, and particularly preferably 1-4 m 2 / g. Metallic silicon is not a granulated particle, but by using fine particles obtained by an ordinary pulverizer, the specific surface area of metallic silicon is significantly increased, and the reaction rate can be substantially improved. . The supply amount of the metal silicon fine powder is 1 to 100 g of the seed silicon nitride powder.
It is preferably 100 g / Hr, particularly preferably 10 to 50 g / Hr.
【００１７】上記金属ケイ素粉末の流動層への連続的供
給は、窒素又はアンモニアを含む非酸化性ガスに随伴さ
せて供給することが好ましい。この非酸化性ガスは上記
流動層を構成する非酸化性ガスと同様に構成することが
できる。なお、非酸化性ガスの線速は限定されるもので
はないが、０．５〜１０ｍ／ｓ、特に２〜５ｍ／ｓとす
ることが好ましく、金属ケイ素粉末を０．５〜５ｇ／リ
ットル、特に１〜３ｇ／リットルの割合で供給すること
が好ましい。The continuous supply of the above-mentioned metallic silicon powder to the fluidized bed is preferably carried out in association with a non-oxidizing gas containing nitrogen or ammonia. This non-oxidizing gas can be configured in the same manner as the non-oxidizing gas forming the fluidized bed. The linear velocity of the non-oxidizing gas is not limited, but it is preferably 0.5 to 10 m / s, particularly preferably 2 to 5 m / s, and the metal silicon powder is 0.5 to 5 g / liter. It is particularly preferable to supply at a rate of 1 to 3 g / liter.
【００１８】上記金属ケイ素粉末の窒化反応において、
反応温度は１０００〜１５００℃、特に１２００〜１３
５０℃とすることが好ましい。In the nitriding reaction of the above metal silicon powder,
The reaction temperature is 1000 to 1500 ° C., particularly 1200 to 13
The temperature is preferably 50 ° C.
【００１９】この窒化反応で得られた窒化ケイ素は排ガ
スと共に連続的に排出し、回収するが、得られた窒化ケ
イ素は必要に応じ２次又は多次にわたり上記操作を繰り
返し、窒化反応を行わせることができる。The silicon nitride obtained by this nitriding reaction is continuously discharged and recovered together with the exhaust gas, and the obtained silicon nitride is subjected to the nitriding reaction by repeating the above operation for secondary or multi-order as necessary. be able to.
【００２０】[0020]
【実施例】以下、実施例と比較例を示し、本発明を具体
的に説明するが、本発明は下記の実施例に制限されるも
のではない。EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.
【００２１】［実施例１〜３、比較例１〜３］図１に示
した窒化ケイ素の連続製造機を用いて窒化ケイ素粉末を
製造した。まず、内径８０ｍｍ，均熱部の長さ５００ｍ
ｍのムライト質チューブ製の反応室２を有する反応器１
中に、種窒化ケイ素或いは比較のため金属ケイ素粉末５
００ｇを装填した。反応室２はその周りに取り付けられ
たヒーター３によって表１に示す温度に加熱した。次い
で、窒素と水素との混合ガスを反応ガス及び流動ガスと
して表１に示す流量で反応ガス供給口４から反応器１に
供給した。供給された混合ガスは反応器１の上方に流
れ、ガス反応室２に備えられたガス分散板５の上方に流
動層６を形成した。流動層６の形成と共に分散機７を作
動させ（なお、図中８はホッパー９を備えた混合機構で
ある）、窒素ガスに同伴・分散させた表１に示した大き
さの原料金属ケイ素を２００ｇ／Ｈｒの割合で原料供給
管１０を通して流動層６に連続的に供給し、流動層６の
層高を３００ｍｍに保持した状態で流動層６から窒化ケ
イ素を排ガスに同伴させ、窒化ケイ素粉末排出管１１を
通して取り出した。取り出された窒化ケイ素を分離器１
２において窒化ケイ素粉末とガスとに分離した。窒化ケ
イ素粉末は回収器１３によって回収され、ガスはガス精
製装置１４に送られた。なお、実施例２については、上
記操作を繰り返し、２段窒化した。[Examples 1 to 3, Comparative Examples 1 to 3] Silicon nitride powder was manufactured using the continuous silicon nitride manufacturing machine shown in FIG. First, the inner diameter is 80 mm, the length of the soaking part is 500 m
m Reactor 1 having a reaction chamber 2 made of mullite tube
In the seed silicon nitride or metal silicon powder 5 for comparison
00g was loaded. The reaction chamber 2 was heated to the temperature shown in Table 1 by a heater 3 attached around it. Then, a mixed gas of nitrogen and hydrogen was supplied as a reaction gas and a flowing gas to the reactor 1 from the reaction gas supply port 4 at the flow rates shown in Table 1. The supplied mixed gas flowed above the reactor 1 and formed a fluidized bed 6 above the gas dispersion plate 5 provided in the gas reaction chamber 2. When the fluidized bed 6 is formed, the disperser 7 is operated (8 in the figure is a mixing mechanism equipped with a hopper 9), and the raw material metallic silicon of the size shown in Table 1 is entrained and dispersed in nitrogen gas. 200 g / Hr is continuously supplied to the fluidized bed 6 through the raw material supply pipe 10, and silicon nitride is entrained in the exhaust gas from the fluidized bed 6 while keeping the bed height of the fluidized bed 6 at 300 mm, and the silicon nitride powder is discharged. Removed through tube 11. The silicon nitride taken out is separated 1
In 2, the silicon nitride powder and gas were separated. The silicon nitride powder was recovered by the recovery device 13, and the gas was sent to the gas purification device 14. In addition, about Example 2, the said operation was repeated and two steps of nitriding were carried out.
【００２２】上記の窒化ケイ素の物性及び流動性を表２
に示した。表２から認められるように、良好な流動層６
を形成させるため、反応開始時の流動粒子の平均粒子径
は、原料金属ケイ素の平均粒子径に応じて自由に変える
ことができるが、原料金属ケイ素の平均粒子径が小さく
比表面積が大きいほど、窒化率は向上する。例えば、平
均粒子径が３７μｍのとき窒化率は９５％（実施例
１）、平均粒子径が２．７μｍのとき窒化率は９８％
（実施例３）であった。また、上述の装置にもう１つ反
応室を設置し、窒化ケイ素粉末排出管１１から排出され
た窒化生成物を２段窒化を行うことで、多少金属ケイ素
の平均粒子が大きくても窒化率１００％，α相率９２％
（実施例２）の高α相率窒化ケイ素粉末を安定的に得る
ことができた。Table 2 shows the physical properties and fluidity of the above silicon nitride.
It was shown to. As can be seen from Table 2, good fluidized bed 6
Therefore, the average particle size of the fluidized particles at the start of the reaction can be freely changed according to the average particle size of the raw material metal silicon, but as the average particle size of the raw material metal silicon is small and the specific surface area is large, The nitriding rate is improved. For example, the nitriding rate is 95% when the average particle diameter is 37 μm (Example 1), and the nitriding rate is 98% when the average particle diameter is 2.7 μm.
(Example 3). Further, another reaction chamber is installed in the above-mentioned apparatus, and the nitriding product discharged from the silicon nitride powder discharging pipe 11 is subjected to two-stage nitriding, so that the nitriding rate of 100 is obtained even if the average particle size of metallic silicon is large. %, Α phase rate 92%
The high α phase silicon nitride powder of (Example 2) could be stably obtained.
【００２３】しかし、反応開始時の流動粒子として金属
ケイ素を用いた場合（比較例１，２）、流動層内が凝集
・閉塞したために窒化ケイ素は排出されなかった。ま
た、同様に反応開始時の流動粒子として窒化ケイ素を用
いた場合でも、その平均粒子径が５０μｍ未満（比較例
３）では、微粉末の発生により、窒化ケイ素排出管１０
が閉塞し、窒化ケイ素は排出されなかった。However, when metallic silicon was used as the fluidized particles at the start of the reaction (Comparative Examples 1 and 2), silicon nitride was not discharged because the inside of the fluidized bed was aggregated and blocked. Similarly, even when silicon nitride is used as the fluidized particles at the start of the reaction, if the average particle size is less than 50 μm (Comparative Example 3), the generation of fine powder causes generation of the silicon nitride discharge pipe 10.
Was clogged and silicon nitride was not discharged.
【００２４】[0024]
【表１】 [Table 1]
【００２５】[0025]
【表２】 [Table 2]
【００２６】[0026]
【発明の効果】以上説明したように、本発明の窒化ケイ
素粉末の製造方法は、工業的に得られる粒度の金属ケイ
素微粉末を原料とした場合でも、α相率に代表される品
質が均質な窒化ケイ素粉末を工業的規模で安価に生産し
得るものである。As described above, according to the method for producing a silicon nitride powder of the present invention, even if the fine powder of metallic silicon having an industrially obtained grain size is used as a raw material, the quality represented by the α phase ratio is uniform. It is possible to inexpensively produce various silicon nitride powders on an industrial scale.
【図１】本発明の実施に用いる窒化ケイ素の連続製造機
である。FIG. 1 is a continuous silicon nitride manufacturing machine used for carrying out the present invention.
１ 反応器 ２ 反応室 ３ ヒーター ４ 反応ガス供給口 ５ ガス分散板 ６ 流動層 ７ 分散機 ８ 混合機構 ９ ホッパ− １０ 原料供給管 １１ 窒化ケイ素粉末排出管 １２ 分離器 １３ 回収器 １４ ガス精製装置 1 Reactor 2 Reaction Chamber 3 Heater 4 Reaction Gas Supply Port 5 Gas Dispersion Plate 6 Fluidized Bed 7 Disperser 8 Mixing Mechanism 9 Hopper 10 Raw Material Supply Pipe 11 Silicon Nitride Powder Discharge Pipe 12 Separator 13 Collector 14 Gas Purifier
Claims (1)
０００μｍの種窒化ケイ素粉末と窒素又はアンモニアを
含む非酸化性ガスとから流動層を形成させ、該流動層中
に平均粒子径が１５０μｍ以下の金属ケイ素微粉末を連
続的に供給し、該金属ケイ素微粉末を窒化して窒化ケイ
素を得ると共に、該窒化ケイ素を連続的に排出させて窒
化ケイ素粉末を得ることを特徴とする窒化ケイ素粉末の
製造方法。1. The average particle size is 50 to 1 in advance at the start of the reaction.
000 μm seed silicon nitride powder and a non-oxidizing gas containing nitrogen or ammonia are used to form a fluidized bed, and fine metal silicon powder having an average particle size of 150 μm or less is continuously fed into the fluidized bed to obtain the metal silicon. A method for producing a silicon nitride powder, which comprises nitriding the fine powder to obtain silicon nitride and continuously discharging the silicon nitride to obtain a silicon nitride powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3021649A JP2541019B2 (en) | 1991-01-22 | 1991-01-22 | Method for producing silicon nitride powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3021649A JP2541019B2 (en) | 1991-01-22 | 1991-01-22 | Method for producing silicon nitride powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04240106A JPH04240106A (en) | 1992-08-27 |
| JP2541019B2 true JP2541019B2 (en) | 1996-10-09 |
Family
ID=12060902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3021649A Expired - Fee Related JP2541019B2 (en) | 1991-01-22 | 1991-01-22 | Method for producing silicon nitride powder |
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| Country | Link |
|---|---|
| JP (1) | JP2541019B2 (en) |
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| CN112794295B (en) * | 2021-03-02 | 2022-10-18 | 北京科技大学 | Method and device for continuously synthesizing amorphous/microcrystalline silicon nitride powder under normal pressure |
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- 1991-01-22 JP JP3021649A patent/JP2541019B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH04240106A (en) | 1992-08-27 |
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