JPH04240106A - Production of silicon nitride powder - Google Patents
Production of silicon nitride powderInfo
- Publication number
- JPH04240106A JPH04240106A JP2164991A JP2164991A JPH04240106A JP H04240106 A JPH04240106 A JP H04240106A JP 2164991 A JP2164991 A JP 2164991A JP 2164991 A JP2164991 A JP 2164991A JP H04240106 A JPH04240106 A JP H04240106A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- fluidized bed
- powder
- silicon
- nitride powder
- 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.)
- Granted
Links
- 229910052581 Si3N4 Inorganic materials 0.000 title claims abstract description 64
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims abstract description 64
- 239000000843 powder Substances 0.000 title claims abstract description 48
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 14
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000002245 particle Substances 0.000 claims abstract description 45
- 239000007789 gas Substances 0.000 claims abstract description 33
- 239000011863 silicon-based powder Substances 0.000 claims abstract description 29
- 238000005121 nitriding Methods 0.000 claims abstract description 27
- 230000001590 oxidative effect Effects 0.000 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims description 33
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 24
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 20
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 229910021529 ammonia Inorganic materials 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 3
- 239000002184 metal Substances 0.000 abstract description 27
- 239000010703 silicon Substances 0.000 abstract description 24
- 229910052710 silicon Inorganic materials 0.000 abstract description 24
- 239000002994 raw material Substances 0.000 abstract description 10
- 239000012495 reaction gas Substances 0.000 abstract description 7
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 239000002912 waste gas Substances 0.000 abstract 1
- 238000000034 method Methods 0.000 description 10
- 229910001111 Fine metal Inorganic materials 0.000 description 9
- 229910001873 dinitrogen Inorganic materials 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 230000005465 channeling Effects 0.000 description 3
- 239000011856 silicon-based particle Substances 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000006757 chemical reactions by type Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000005243 fluidization Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011361 granulated particle Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen(.) Chemical compound [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000009491 slugging Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000010671 solid-state reaction Methods 0.000 description 1
Landscapes
- Ceramic Products (AREA)
- Silicon Compounds (AREA)
Abstract
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 that can nitride fine metal silicon 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 Hitherto, a method using a fluidized bed has been 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 between metallic silicon powder and a reaction gas, and then heated. However, in this fluidized bed reaction type silicon nitride powder manufacturing method, the metallic silicon powder as a raw material is directly exposed to a high temperature atmosphere. As a result, the metal silicon powder introduced into the fluidized bed melts immediately, and particles fuse and aggregate, resulting in a decrease in specific surface area and a significant drop in reaction rate, forming a fluidized bed. The problem is that it is difficult to In this case, lowering the temperature of the fluidized bed significantly reduces the nitriding reaction rate.
【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。[0003] Conventionally, in order to solve this problem, a fluidized bed was formed with metal silicon powder and a reactive gas, and when this was heated, the temperature increase rate was set at 30 to 150°C/
A method for obtaining silicon nitride powder of stable quality by controlling the Hr to prevent melting and agglomeration of metal silicon powder
No. 97110) has been proposed, but this method requires a long time to heat up and cool down the furnace, resulting in poor productivity.
【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。[Problems to be Solved by the Invention] As a method for solving the above-mentioned problems of the conventional manufacturing method, an improved method for manufacturing silicon nitride powder using a fluidized bed method previously proposed by the present applicant (Japanese Patent Application Laid-Open No. 1-195954) No.). This manufacturing method preferably uses metal silicon powder with a particle size of 149 μm to 4 m.
granulated to about m, and formed from silicon nitride powder and a non-oxidizing reaction gas containing nitrogen gas or ammonia gas,
The nitrided product is continuously supplied into a first fluidized bed whose temperature is maintained at 1000 to 1400°C, and after the first nitriding reaction is performed in the first fluidized bed, the nitrided product is continuously supplied from this first fluidized bed. At the same time, this is further supplied to a second fluidized bed formed from silicon nitride powder and a non-oxidizing reaction gas containing nitrogen gas or ammonia gas, and the unreacted nitriding raw material is nitrided in the second fluidized bed. A secondary nitriding reaction is performed, and according to this method, silicon nitride powder with less variation in quality such as α phase ratio can be stably and efficiently produced.
【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 method of the prior application recommends granulating the metallic silicon powder, and the reasons for granulating the metallic silicon in advance are as follows: (1) good fluidization state in the fluidized bed; (2)
) Preventing the surface area from decreasing due to melting of metal silicon and preventing clogging in the fluidized bed. However, the general form of the reaction performed using a fluidized bed is to use nitrogen gas or nitrogen gas as a fluidizing gas. Air between ammonia gas and metal silicon
Considering that the reaction is a solid-state reaction, it is preferable to reduce the particle size of the metal silicon powder as a raw material and increase the specific surface area in order to improve the reaction rate. Furthermore, since silicon nitride obtained by a gas-solid reaction must ultimately be pulverized to a particle size having an appropriate distribution on the submicron order, it is desirable that the metal silicon particles be fine. Metallic silicon, which is a raw material, is pulverized as finely as possible using industrially available pulverization equipment, but usually the economically obtainable fine particles have a BET specific surface area of 4 m2/g and an average particle size. It 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。[0006] Therefore, it is desired to efficiently produce silicon nitride powder 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。[0007] The present invention was made in response to the above-mentioned needs, and it is possible to efficiently directly nitride fine metallic silicon with an average particle size of 150 μm or less, particularly 50 μm or less, and achieve a high nitridation rate of metallic silicon. It is an object of the present invention to provide a method for producing silicon nitride powder that is both possible and 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 effects for solving the problem] The present inventors have
As a result of intensive studies to achieve the above objective, we found that a fluidized bed was formed in advance from seed silicon nitride powder with an average particle size of 50 to 1000 μm and a non-oxidizing gas containing nitrogen or ammonia, and the raw material was added to the fluidized bed. The average particle size of
Metallic silicon powder of 50 μm or less, particularly 50 μm or less, is entrained and dispersed in a non-oxidizing gas containing nitrogen or ammonia and continuously introduced into the fluidized bed to produce silicon nitride, and at the same time, the silicon nitride is converted into exhaust gas. It has been found that by entraining and continuously discharging the fine metal silicon powder, silicon nitride powder can be produced at low cost with a high nitriding rate using the fine metal silicon powder as it is.
【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 production method of silicon nitride powder using a fluidized bed reaction type, fine powder of metallic silicon having a particle size that can be obtained industrially has a strong interparticle force, so if it is left as it is, it will cause channeling, etc. It is difficult to maintain a good fluidized bed. Generally, the fluidized bed has a different fluid state depending on the density, particle size, and particle size distribution of the fluidized particles. For example, Geldart's classification “Pow
der Technology, 7, 285 (197
3); 19, 133 (1978)”, “A
” particles are suitable for forming a good fluidized bed,
Furthermore, "A'" particles containing an appropriate amount of particles with a particle size of 44 μm or less, which is called a "good fraction," are said to be particles particularly suitable for forming a good fluidized bed. According to this classification, the above-mentioned industrially obtained pulverized metallic silicon particles having an average particle diameter of 1 to 44 μm belong to “C” particles. "C" particles are said to have strong interparticle forces that cause channeling in the fluidized bed, making it extremely difficult to form a good fluid state.
【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 approximately normal pressure is around 1200°C, and the melting temperature of metallic silicon is thought to be 1300 to 1400°C. In a gas-solid reaction in which metallic silicon is nitrided with nitrogen or ammonia gas, nitriding starts from the surface and progresses as nitrogen diffuses into the interior. This reaction is 140-18
This is an exothermic reaction that generates a large amount of heat, 0 kcal/mol, and it is very important that the heat is removed smoothly. This is because if metal silicon reaches the melting temperature before the nitriding reaction progresses uniformly and a silicon nitride film is formed on the surface of metal silicon, melting and coalescence between metal silicon particles will occur, and the specific surface area will drastically decrease. At the same time, the fluidized bed becomes blocked, 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。[0011] In the present invention, the average particle diameter is set in advance from 50 to 1000.
A fluidized bed is formed with seed silicon nitride powder of 150 μm or less, and fine metal silicon powder with an average particle size of 150 μm or less is entrained and dispersed in a non-oxidizing gas containing nitrogen or ammonia to continuously form a fluidized bed. By introducing metal silicon into a liquid, it is possible to form a good fluidized bed of metal silicon using the particle size that makes it difficult to form a uniform fluidized bed, and it is possible to form a good fluidized bed of metal silicon, which prevents agglomeration and coarsening of fine metal silicon powder. In addition, the metal silicon fine powder is allowed to adhere to and grow on the seed silicon nitride powder to cause nitridation, and the silicon nitride obtained by nitriding is accompanied by the exhaust gas and continuously discharged. As a result, there is no need to perform a pretreatment step of granulating, drying, and calcining the metal silicon powder, and the above-mentioned "C" having an average particle size of 50 μm or less is eliminated.
Even when using metal silicon powder, which is classified as particles, it is possible to maintain a good fluidized state in the fluidized bed, increasing the cost advantage of using a fluidized bed reaction, and having a large specific surface area and a small average particle size. The inventors have discovered that silicon nitride powder can be efficiently obtained at a high reaction rate by using small metallic silicon powder as it is, and have accomplished 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, in the present invention, a fluidized bed is formed in advance from seed silicon nitride powder having an average particle size of 50 to 1000 μm and a non-oxidizing gas containing nitrogen or ammonia at the start of the reaction, and the average particle size is Nitriding characterized by continuously supplying fine metal silicon powder of 150 μm or less, nitriding the fine metal silicon powder to obtain silicon nitride, and continuously discharging the silicon nitride 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５０
〜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、５０
μｍ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。[0013] The present invention will be explained in more detail below. The seed silicon nitride powder used in the present invention has an average particle diameter of 50
~1000 μm, particularly preferably 200 to 500 μm. When the average particle size is less than 50 μm, it is difficult for the fluidized bed to maintain a good fluid state due to channeling, etc. On the other hand, when the average particle size exceeds 1000 μm, the fluidization start speed increases and the gas flow rate becomes difficult to maintain. As the bubble size increases, slugging occurs, and 50
As in the case of less than μm, it becomes difficult to maintain a good fluid state. Note that by repeating growth and destruction, the seed silicon nitride powder can always exist in the fluidized bed with an average particle diameter of 50 to 1000 μm.
【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 seed silicon nitride powder is used to form a fluidized bed in advance 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 fluidizing 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。The non-oxidizing gas contains nitriding or ammonia, but if necessary, an inert gas such as Ar or He, or a non-oxidizing gas such as H2 may be mixed. 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, metal silicon powder is continuously fed into the fluidized bed, and a nitriding reaction is carried out in the fluidized bed to convert the metal silicon powder into silicon nitride powder. Here, the average particle size of the metallic silicon fine powder is 150 μm or less, and preferably 1 to 44 μm. If the average particle diameter exceeds 150 μm, the progress of the nitriding reaction may be hindered. In addition, it is desirable that the specific surface area of metal silicon be large, but since pulverization costs too much,
It is preferably 15 m2/g, particularly 1 to 4 m2/g. By using fine particles of silicon metal obtained using a normal pulverizer instead of granulated particles, the specific surface area of silicon metal can be significantly increased, which can substantially improve the reaction rate. . The supply amount of the above metal silicon fine powder is 1 to 100 g of seed silicon nitride powder.
It is preferable to set it as 100g/Hr, especially 10-50g/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 metal silicon powder is preferably continuously supplied to the fluidized bed while being accompanied by a non-oxidizing gas containing nitrogen or ammonia. This non-oxidizing gas can be configured in the same manner as the non-oxidizing gas constituting the fluidized bed. Although the linear velocity of the non-oxidizing gas is not limited, it is preferably 0.5 to 10 m/s, particularly 2 to 5 m/s, and the linear velocity of the non-oxidizing gas is preferably 0.5 to 5 g/liter, In particular, it is preferable to supply it 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 metal silicon powder,
The reaction temperature is 1000-1500°C, especially 1200-13
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 in this nitriding reaction is continuously discharged and recovered together with the exhaust gas, but the silicon nitride obtained is subjected to the above operation twice or multiple times as necessary to carry out the nitriding reaction. 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 specifically explained below 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１２
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 produced using the continuous silicon nitride production machine shown in FIG. First, the inner diameter is 80 mm, and the length of the soaking part is 500 m.
Reactor 1 having a reaction chamber 2 made of mullite tubes of m
Inside, 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 installed around it. Next, a mixed gas of nitrogen and hydrogen was supplied as a reaction gas and a fluidizing 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 distribution plate 5 provided in the gas reaction chamber 2. At the same time as 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 metal silicon having the size shown in Table 1 is entrained and dispersed in nitrogen gas. The raw material is continuously supplied to the fluidized bed 6 through the raw material supply pipe 10 at a rate of 200 g/Hr, and while the height of the fluidized bed 6 is maintained at 300 mm, silicon nitride is entrained in the exhaust gas from the fluidized bed 6, and the silicon nitride powder is discharged. It was taken out through tube 11. The extracted silicon nitride is transferred to a separator 12
It was separated into silicon nitride powder and gas. The silicon nitride powder was recovered by a recovery device 13, and the gas was sent to a gas purification device 14. In addition, for Example 2, the above operation was repeated to perform two-stage nitriding.
【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 seen from Table 2, a good fluidized bed 6
In order to form The nitriding rate improves. For example, when the average particle diameter is 37 μm, the nitriding rate is 95% (Example 1)
When the average particle diameter was 2.7 μm, the nitridation rate was 98% (Example 3). In addition, by installing another reaction chamber in the above-mentioned apparatus and performing two-stage nitriding on the nitrided product discharged from the silicon nitride powder discharge pipe 11, the nitriding rate can be maintained at 100 even if the average particles of metallic silicon are somewhat large. %, and a high α phase ratio silicon nitride powder with an α phase ratio of 92% (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 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 agglomerated and clogged. Similarly, even when silicon nitride is used as fluidized particles at the start of the reaction, the average particle diameter is less than 50 μm (Comparative Example 3
), the silicon nitride discharge pipe 10 was blocked due to the generation of fine powder, 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。[Effects of the Invention] As explained above, the method for producing silicon nitride powder of the present invention has a uniform quality represented by the α phase ratio even when using industrially obtained fine metal silicon powder as a raw material. This makes it possible to produce silicon nitride powder on an industrial scale at low cost.
【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 shows a continuous silicon nitride production machine used in the practice of 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 distribution plate 6 Fluidized bed 7 Dispersion machine 8 Mixing mechanism 9 Hopper 10 Raw material supply pipe 11 Silicon nitride powder discharge pipe 12 Separator 13 Recovery device 14 Gas purification equipment
Claims (1)
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、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。Claim 1: At the start of the reaction, the average particle diameter is 50~
A fluidized bed is formed from a seed silicon nitride powder of 1000 μm and a non-oxidizing gas containing nitrogen or ammonia, and fine metallic silicon powder having an average particle size of 150 μm or less is continuously supplied into the fluidized bed. A method for producing silicon nitride powder, which comprises nitriding fine powder to obtain silicon nitride, and continuously discharging the silicon nitride to obtain 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 true JPH04240106A (en) | 1992-08-27 |
| JP2541019B2 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 |
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| JP (1) | JP2541019B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051856A (en) * | 2009-09-03 | 2011-03-17 | Denki Kagaku Kogyo Kk | Method for producing high-purity silicon nitride fine powder |
| CN112794295A (en) * | 2021-03-02 | 2021-05-14 | 北京科技大学 | Method and device for continuously synthesizing amorphous/microcrystalline silicon nitride powder under normal pressure |
-
1991
- 1991-01-22 JP JP3021649A patent/JP2541019B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051856A (en) * | 2009-09-03 | 2011-03-17 | Denki Kagaku Kogyo Kk | Method for producing high-purity silicon nitride fine powder |
| CN112794295A (en) * | 2021-03-02 | 2021-05-14 | 北京科技大学 | Method and device for continuously synthesizing amorphous/microcrystalline silicon nitride powder under normal pressure |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2541019B2 (en) | 1996-10-09 |
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