JP2018035388A - Silver powder production method and silver powder production device - Google Patents
Silver powder production method and silver powder production device Download PDFInfo
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- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 title claims abstract description 336
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 101
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 197
- 229910052709 silver Inorganic materials 0.000 claims abstract description 194
- 239000004332 silver Substances 0.000 claims abstract description 194
- 229910052751 metal Inorganic materials 0.000 claims abstract description 148
- 239000002184 metal Substances 0.000 claims abstract description 148
- 239000007921 spray Substances 0.000 claims abstract description 84
- 239000002245 particle Substances 0.000 claims abstract description 53
- 230000000903 blocking effect Effects 0.000 claims abstract description 52
- 239000010409 thin film Substances 0.000 claims description 48
- 229910021385 hard carbon Inorganic materials 0.000 claims description 40
- 239000010408 film Substances 0.000 claims description 28
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 26
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 23
- 239000008367 deionised water Substances 0.000 claims description 22
- 229910021641 deionized water Inorganic materials 0.000 claims description 22
- 239000000155 melt Substances 0.000 claims description 16
- 238000005507 spraying Methods 0.000 claims description 16
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 15
- 230000007423 decrease Effects 0.000 claims description 12
- 239000010419 fine particle Substances 0.000 claims description 11
- 238000010298 pulverizing process Methods 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 9
- 229910003460 diamond Inorganic materials 0.000 claims description 8
- 239000010432 diamond Substances 0.000 claims description 8
- 229910052582 BN Inorganic materials 0.000 claims description 7
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 7
- 238000002242 deionisation method Methods 0.000 claims description 7
- 239000000395 magnesium oxide Substances 0.000 claims description 7
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 7
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 7
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 7
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 7
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 7
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 238000000034 method Methods 0.000 description 41
- 239000000843 powder Substances 0.000 description 40
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 17
- 229910002804 graphite Inorganic materials 0.000 description 17
- 239000010439 graphite Substances 0.000 description 17
- 239000007788 liquid Substances 0.000 description 15
- 239000002994 raw material Substances 0.000 description 15
- 239000012530 fluid Substances 0.000 description 10
- 239000012535 impurity Substances 0.000 description 10
- 238000009692 water atomization Methods 0.000 description 9
- 238000000889 atomisation Methods 0.000 description 8
- 239000011247 coating layer Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000001816 cooling Methods 0.000 description 6
- 239000008235 industrial water Substances 0.000 description 6
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- 230000002265 prevention Effects 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- VXQBJTKSVGFQOL-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethyl acetate Chemical compound CCCCOCCOCCOC(C)=O VXQBJTKSVGFQOL-UHFFFAOYSA-N 0.000 description 4
- 229920002799 BoPET Polymers 0.000 description 4
- 239000001856 Ethyl cellulose Substances 0.000 description 4
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229920001249 ethyl cellulose Polymers 0.000 description 4
- 235000019325 ethyl cellulose Nutrition 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000009689 gas atomisation Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000000634 powder X-ray diffraction Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 238000005118 spray pyrolysis Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- 230000000930 thermomechanical effect Effects 0.000 description 2
- 238000005169 Debye-Scherrer Methods 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000005280 amorphization Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000001144 powder X-ray diffraction data Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
- 229910021642 ultra pure water Inorganic materials 0.000 description 1
- 239000012498 ultrapure water Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052984 zinc sulfide Inorganic materials 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
Abstract
Description
本願発明は、水アトマイズ、すなわち溶融銀柱の状態で流下させた溶融銀に水を噴霧することで銀粒子を生成する工程、を含む銀粉末製造方法と、当該製造方法を使用可能な銀粉末製造装置に関する。 The present invention relates to a method for producing silver particles comprising water atomization, that is, a step of producing silver particles by spraying water onto molten silver that has flowed down in the form of molten silver columns, and a silver powder that can use the production method. It relates to a manufacturing apparatus.
銀粉末は、装飾品の他に厚膜導電性ペースト、スルーホール用ペースト、導電性接着剤、インダクター、ＭＬＣＣ用電極、ＬＴＣＣ用電極、太陽電池用電極等のエレクトロニクス分野での原料として幅広く使用されている。上記エレクトロニクス分野で導電性ペースト等の原料として使用される銀粉末には、純度の高さ、結晶化、小さな平均粒径、粒径分布の一定の広がり、及び非球形の粒子形態の存在が求められる。高い電気伝導度と、導電性ペースト等の焼結時の低収縮性を確保するためである。 Silver powder is widely used as a raw material in electronics fields such as thick film conductive paste, through-hole paste, conductive adhesive, inductor, MLCC electrode, LTCC electrode, solar cell electrode, etc. ing. Silver powder used as a raw material for conductive pastes in the electronics field requires high purity, crystallization, small average particle size, constant spread of particle size distribution, and presence of non-spherical particle morphology. It is done. This is to ensure high electrical conductivity and low shrinkage during sintering of a conductive paste or the like.
このような用途に適した銀粉末の製造方法として現在、湿式還元法、粉砕法、噴霧熱分解法、アトマイズ法が知られている。 Currently, wet reduction methods, pulverization methods, spray pyrolysis methods, and atomization methods are known as methods for producing silver powder suitable for such applications.
湿式還元法は、銀を硝酸等で溶解した後、沈殿剤と還元剤を添加して銀粉末を調製する方法であり、微細な粒径の銀粉末を製造することができる。しかし、溶媒中の分散性を維持するために界面活性剤を添加することから純粋な銀粉末を得ることができない欠点がある。また、固液分離、乾燥工程を含めて製造時間が非常に長く、大量の溶媒を使用するため環境負荷も大きい。
粉砕法は，銀の塊をボールミル等で粉砕する方法である。粉砕の際に大きな機械的エネルギーを要すること、及び長時間の粉砕処理を必要とする欠点がある。
噴霧熱分解法は、銀の原料塩を水溶液とし、超音波やノズルからの噴霧し、数百度に加熱した電気炉を通過させて銀粉末を製造する方法である。生産効率が低く、又、熱分解後の排ガス処理にコストがかかる点を考慮すると、現状では工業生産に適さない方法である。
The wet reduction method is a method of preparing silver powder by dissolving silver with nitric acid and the like and then adding a precipitating agent and a reducing agent, and a silver powder having a fine particle size can be produced. However, there is a drawback that a pure silver powder cannot be obtained because a surfactant is added to maintain dispersibility in a solvent. In addition, the production time including the solid-liquid separation and drying process is very long, and a large amount of solvent is used.
The pulverization method is a method of pulverizing a lump of silver with a ball mill or the like. There are drawbacks in that a large mechanical energy is required for pulverization and a long pulverization process is required.
The spray pyrolysis method is a method in which a silver raw material salt is made into an aqueous solution, sprayed from ultrasonic waves or nozzles, and passed through an electric furnace heated to several hundred degrees to produce silver powder. Considering the low production efficiency and the cost of exhaust gas treatment after pyrolysis, this method is not suitable for industrial production at present.
アトマイズ法は、湿式還元法に比べて純粋な金属や合金を溶媒レスで短時間に製造でき、生産効率が高く、エネルギー損失も少ない方法である。 The atomization method is a method in which pure metals and alloys can be produced in a short time without a solvent compared to the wet reduction method, and the production efficiency is high and the energy loss is small.
アトマイズ法にはガスアトマイズ法と水アトマイズ法がある。ガスアトマイズ法で製造される金属粉末の粒径は１０μｍ以上と大きく、一般にエレクトロニクス分野での使用には適さない。一方、水アトマイズ法で製造される金属粉末の粒径は微細であり、エレクトロニクス分野で使用することができる。 The atomization method includes a gas atomization method and a water atomization method. The particle size of the metal powder produced by the gas atomization method is as large as 10 μm or more and is generally not suitable for use in the electronics field. On the other hand, the metal powder produced by the water atomization method has a fine particle size and can be used in the electronics field.
従来の水アトマイズ法には、溶融金属を流下させる溶湯ノズル孔の目詰まりや、ブロッキング現象のために、しばしば製造が中断され、長時間の連続操業が難しいという欠点があった。 The conventional water atomization method has a drawback in that production is often interrupted due to clogging of a molten metal nozzle hole that causes molten metal to flow down and a blocking phenomenon, making continuous operation difficult for a long time.
ここでブロッキング現象について説明する。水アトマイズ法においては、溶融金属柱の状態で流下する溶融金属に噴霧ノズルから水を噴霧し、溶融金属を粉砕して金属微粒子を生成する。噴霧ノズルは通常、溶融金属柱を囲うように配置された環状のノズルである。ブロッキング現象とは、粉砕された後、本来下方へ進行するべき溶融金属の一部が半凝固状態で、噴霧された水の衝撃を受けて上方に向けて飛散し、噴霧ノズルに付着・堆積したり、生成した金属微粒子が上方に飛散し、噴霧ノズルに付着・堆積して、溶融金属の流下経路を妨げることを言う。 Here, the blocking phenomenon will be described. In the water atomization method, water is sprayed from a spray nozzle onto the molten metal flowing down in the state of a molten metal column, and the molten metal is pulverized to generate metal fine particles. The spray nozzle is usually an annular nozzle arranged to surround the molten metal column. The blocking phenomenon means that after pulverization, a part of the molten metal that should have traveled downward is in a semi-solid state, splashed upwards under the impact of sprayed water, and adheres and accumulates on the spray nozzle. In other words, the generated fine metal particles are scattered upward, adhere to and deposit on the spray nozzle, and obstruct the flow path of the molten metal.
ブロッキング現象の防止方法に係る従来技術はいくつか存在する。
１つの方法は、環状の噴霧ノズルから逆円錐状に噴霧される噴霧水の角度（逆円錐の頂角）を小さく設定し、斜め上方から鉛直に近い急な角度で溶融金属柱に向けて水を噴霧することで、溶融金属の一部が上方に向けて飛散しにくいようにする方法である。しかし当該方法には、上記頂角を小さく設定すると噴霧水が溶融金属柱に加える衝撃が小さくなり、金属粉末の製造効率が落ちるという欠点がある。
There are several conventional techniques related to a blocking phenomenon prevention method.
One method is to set the angle of the sprayed water sprayed in an inverted cone shape from the annular spray nozzle (vertical angle of the inverted cone) to be small, and water toward the molten metal column at a steep angle close to the vertical from obliquely above. This is a method in which a part of the molten metal is prevented from scattering upward by spraying. However, this method has a drawback that if the apex angle is set small, the impact of spray water on the molten metal column becomes small, and the production efficiency of the metal powder decreases.
本願発明者は後述するように、噴霧された水の、溶融金属柱に衝突した後の進行方向を変更して再び溶融金属柱に衝突させることにより、上記頂角を小さく設定した場合に製造効率が低下するという上記欠点を回避できることを発見した。この発見は現時点で本願発明者が知る限り、先行技術文献には一切記載されていない。それを次に説明する。
図１０に示すのは、特開２００７−２９１４５４号公報（特許文献１）に開示された、溶融金属柱に衝突した後の噴霧水の進行方向を変化させる進行方向変更手段を有する金属粉末製造装置１０１である。当該装置１０１は、溶融金属１Ｑを供給する供給部１０２と、供給部１０２の下方に設けられた液体噴出部２０３と、液体噴出部２０３の下方に設けられたノズル１０６および筒状体１０９Ａとを有している。ノズル１０６は、液体ジェット１Ｓ４（第２の液体）を噴射するオリフィス１６４を有しており、この液体ジェット１Ｓ４に、分散液１Ｃ１が衝突すると、分散液１Ｃ１の進行方向は強制的に変化する。すなわち、ノズル１０６は、分散液１Ｃ１の進行方向を変化させる進行方向変更手段を構成する。
As will be described later, the inventor of the present application changes the traveling direction of the sprayed water after colliding with the molten metal column and collides with the molten metal column again, thereby reducing the production efficiency when the apex angle is set small. It has been found that the above-mentioned drawback of lowering can be avoided. This discovery is not described in any prior art document as far as the present inventors know. This will be described next.
FIG. 10 shows a metal powder manufacturing apparatus having a traveling direction changing means for changing the traveling direction of spray water after colliding with a molten metal column, disclosed in Japanese Patent Application Laid-Open No. 2007-291454 (Patent Document 1). 101. The apparatus 101 includes a supply unit 102 for supplying molten metal 1Q, a liquid ejection unit 203 provided below the supply unit 102, a nozzle 106 and a cylindrical body 109A provided below the liquid ejection unit 203. Have. The nozzle 106 has an orifice 164 that ejects the liquid jet 1S4 (second liquid). When the dispersion liquid 1C1 collides with the liquid jet 1S4, the traveling direction of the dispersion liquid 1C1 is forcibly changed. That is, the nozzle 106 constitutes a traveling direction changing unit that changes the traveling direction of the dispersion 1C1.
特許文献１の金属粉末製造装置１０１において進行方向変更手段を設ける目的は、アモルファス化が進行した金属粉末を得るためである。進路変更手段がないと、溶融金属が***して生じた多数の液滴１Ｑ１の周囲を覆うように形成された水蒸気層のために、液滴１Ｑ１と液体ジェット１Ｓ１の間の熱伝導が妨げられて十分な冷却速度が得られず、結晶化の進行した金属粉末が得られる。進路変更手段を設けることで、半固化状態の液滴１Ｑ１と水蒸気層とを、これらの慣性の大きさの違いを利用して分離し、冷却速度を確保し、アモルファス化が進行した金属粉末を得ることができる。しかし、進路変更手段として液体ジェット１Ｓ４（第２の液体）の噴射を用いる特許文献１の方法によっては、エレクトロニクス分野における高電導度の導電性ペースト等の原材料に適した、結晶化の進行した金属粉末を得ることはできない。又、特許文献１には、進路変更手段を用いることで、前記頂角が小さい場合にも金属粉末の製造効率が落ちないようにできる旨の記載は一切ない。 The purpose of providing the traveling direction changing means in the metal powder manufacturing apparatus 101 of Patent Document 1 is to obtain a metal powder that has been amorphized. Without the route changing means, the heat conduction between the droplet 1Q1 and the liquid jet 1S1 is hindered due to the water vapor layer formed so as to cover the periphery of the large number of droplets 1Q1 generated by splitting the molten metal. Therefore, a sufficient cooling rate cannot be obtained, and a metal powder having undergone crystallization can be obtained. By providing the course changing means, the semi-solid-state droplet 1Q1 and the water vapor layer are separated by utilizing the difference in the magnitude of their inertia, the cooling rate is ensured, and the metal powder that has been amorphized is removed. Can be obtained. However, depending on the method of Patent Document 1 using the jet of the liquid jet 1S4 (second liquid) as the course changing means, the metal having advanced crystallization suitable for raw materials such as conductive paste having high conductivity in the electronics field It is not possible to obtain a powder. Further, Patent Document 1 has no description that it is possible to prevent the metal powder production efficiency from decreasing even when the apex angle is small by using a course changing means.
ブロッキング現象は、逆円錐状に噴霧される水が溶融金属柱と衝突する収束点近傍で生じる何らかの外乱をきっかけとして、原因不明のまま突発的に生じることも多い。このような外乱の発生を減らすためには、環状の噴霧ノズルから、なるべく全周均一に途切れなく安定して水を噴霧することが望ましい。 The blocking phenomenon is often abruptly generated for unknown reasons, triggered by some disturbance generated near the convergence point where water sprayed in an inverted conical shape collides with a molten metal column. In order to reduce the occurrence of such disturbances, it is desirable to spray water stably from the annular spray nozzle as uniformly as possible throughout the circumference.
図１１に示すのは、上述の特許文献１に開示された、従来の環状の噴霧ノズル２０３の拡大断面図である。液体ジェット１Ｓ１を生成するための噴霧ノズル２０３は、第１の部材２０４と第２の部材２０５の間に形成された間隙２３７を水の流路２３２とする。流路２３２は、下端部に開口するオリフィス２３４と、水２００Ｓを一時的に貯留する貯留部２３５と、貯留部２３５からオリフィス２３４に水２００Ｓを導入する導入路２３６とにより構成される。
オリフィス２３４が下端部に開口しているため、水２００Ｓは縦断面がくさび状をなす導入路２３６の中を斜め下方へと進行し、オリフィス２３４から直接、斜め下方の収束点へと向かう液体ジェット１Ｓ１として噴射される。本願発明者は、水２００Ｓが噴霧ノズル２０３の中を斜め下方へと進行することを特徴とする、このような従来の噴霧ノズル２０３の構成では、液体ジェットに生じた周方向の乱れや時間的な変動が減衰しにくく、全
周均一に途切れなく安定して水を噴霧することが困難であることを見出した。
FIG. 11 is an enlarged cross-sectional view of a conventional annular spray nozzle 203 disclosed in Patent Document 1 described above. The spray nozzle 203 for generating the liquid jet 1 </ b> S <b> 1 uses the gap 237 formed between the first member 204 and the second member 205 as a water flow path 232. The flow path 232 includes an orifice 234 that opens to the lower end, a storage section 235 that temporarily stores the water 200S, and an introduction path 236 that introduces the water 200S from the storage section 235 into the orifice 234.
Since the orifice 234 is open at the lower end, the water 200S travels obliquely downward in the introduction path 236 whose longitudinal section forms a wedge shape, and is a liquid jet directed directly from the orifice 234 toward the convergence point obliquely below. It is injected as 1S1. The inventor of the present application is characterized in that the water 200S travels obliquely downward in the spray nozzle 203, and in such a configuration of the conventional spray nozzle 203, the circumferential disturbance and time caused in the liquid jet It has been found that it is difficult to attenuate water fluctuations and to spray water stably and uniformly over the entire circumference.
ブロッキング現象の防止方法に係る他の従来技術として、溶融金属の一部が仮に上方に向かって飛散しても、噴霧ノズルに付着・堆積しにくくすることを意図した技術が複数ある。 As another conventional technique related to the blocking phenomenon prevention method, there are a plurality of techniques intended to make it difficult to adhere and accumulate on the spray nozzle even if a part of the molten metal scatters upward.
そのような従来技術の１つとして図１２に示すのは、特開昭６２−１５１５０３号公報（特許文献２）に開示された、高圧流体３００Ｗを溶融金属３００Ｍに向けて噴射するための噴霧ノズル３０２の、噴射出口より上方側の壁面３０３に沿って、流体ノズル３０８から付着防止用流体を流すことにより金属粉末の壁面３０３への付着を防止する、金属粉末の製造方法の一実施例である。 One such prior art is shown in FIG. 12 as a spray nozzle disclosed in Japanese Patent Laid-Open No. Sho 62-151503 (Patent Document 2) for injecting a high-pressure fluid 300W toward a molten metal 300M. 302 is an example of a method for producing metal powder, in which adhesion of the metal powder to the wall surface 303 is prevented by flowing an adhesion preventing fluid from the fluid nozzle 308 along the wall surface 303 above the jetting outlet. .
この技術は、溶融金属３００Ｍの飛沫が壁面３０３に向かって飛散しても、壁面３０３に衝突する前に付着防止用流体に接触して急冷凝固し、当該流体とともに下方へ押し流されることにより、壁面３０３に付着・堆積しないようにすることを意図したものである。しかし、この方法では、高圧流体３００Ｗの噴流が引き起こす吸い込み気流により付着防止用流体が吹き飛ばされて壁面３０３の一部が露出した場合や、多量の溶融金属３００Ｍが壁面３０３に触れて接触した場合の焼付を防止できない。 Even if the molten metal 300M splashes toward the wall surface 303, this technique is brought into contact with the adhesion preventing fluid before it collides with the wall surface 303, rapidly solidifies, and is pushed downward together with the fluid. This is intended not to adhere to or accumulate on 303. However, in this method, when the adhesion preventing fluid is blown off by the suction air flow caused by the jet of the high-pressure fluid 300W and a part of the wall surface 303 is exposed, or when a large amount of molten metal 300M touches and contacts the wall surface 303. Cannot prevent seizure.
別の従来技術として図１３に示すのは、特開昭６４−２０３号公報（特許文献３）に開示された、高圧流体４００Ｗを溶融金属４００Ｍの落下流に向けて噴射するための噴霧ノズル４０２の、前記落下流を囲む内壁面４０７を、溶融金属４００Ｍとの接触角が９０°〜１８０°の濡れ性を有する材質により構成することで、前記溶融金属の飛沫が内壁面４０７に付着することを防止する、金属粉末の製造方法である。 As another prior art, FIG. 13 shows a spray nozzle 402 disclosed in Japanese Patent Laid-Open No. 64-203 (Patent Document 3) for injecting a high-pressure fluid 400W toward a falling flow of molten metal 400M. The inner wall surface 407 surrounding the falling flow is made of a material having a wettability with a contact angle of 90 ° to 180 ° with the molten metal 400M, so that the molten metal droplets adhere to the inner wall surface 407. It is a manufacturing method of metal powder which prevents.
この技術は、溶融金属４００Ｍの飛沫が内壁面４０７に向かって飛散しても、内壁面４０７が溶融金属４００Ｍで濡れない性質を有するために、当該飛沫の内壁面４０７への付着が防止され、内壁面４０７に付着・堆積しないようにすることを意図したものである。確かに理論上は、溶融金属４００Ｍとの接触角が９０°〜１８０°の濡れ性を有する材質で内壁面４０７を構成すれば、付着は起こらない。しかし、現実には内壁面４０７の表面は粗くて微細な凹凸を有し、局所的に接触角が９０°未満となる領域が生じて、そのような領域に溶融金属４００Ｍが付着・堆積し、やがてはブロッキング現象へと発展する事象がしばしば起きる。 Even if the molten metal 400M splashes toward the inner wall surface 407, the technology prevents the inner wall surface 407 from being wetted by the molten metal 400M. This is intended not to adhere or accumulate on the inner wall surface 407. Theoretically, if the inner wall surface 407 is made of a material having a wettability with a contact angle with the molten metal 400M of 90 ° to 180 °, adhesion does not occur. However, in reality, the surface of the inner wall surface 407 has rough and fine irregularities, and a region where the contact angle is locally less than 90 ° is generated, and the molten metal 400M adheres and accumulates in such a region, Eventually, an event that develops into a blocking phenomenon occurs.
更に別の従来技術として図１４に示すのは、特開平５−９５１３号公報（特許文献４）に開示された、水噴射ノズル５０５又はその保護ガイド５０６の表面に特定の耐火材料からなる被覆層５０７を構成し、更に水噴射ノズル５０５又はその保護ガイド５０６を冷却することで、溶融金属の飛沫の付着閉塞（ブロッキング現象）を防止する方法である。被覆層５０７は、Ｓｉ３Ｎ４、ＢＮ又はＡｌＮのうち１種又は２種以上を含み、気孔率が５容積％以上である耐火材料からなり、溶融金属の飛沫が接触すると７００℃以上でＳｉ３Ｎ４、ＢＮ又はＡｌＮが分解するから、溶融金属が付着しない。又、冷却水５１４により水噴射ノズル５０５又はその保護ガイド５０６を内部から冷却することで、被覆層５０７を低温に保ち、昇温による被覆層５０７の分解を低減している。 As another prior art, FIG. 14 shows a coating layer made of a specific fireproof material on the surface of the water injection nozzle 505 or its protective guide 506, disclosed in Japanese Patent Laid-Open No. 5-9513 (Patent Document 4). In this method, the water injection nozzle 505 or the protection guide 506 thereof is further cooled to prevent adhesion and blockage (blocking phenomenon) of molten metal droplets. The coating layer 507 is made of a refractory material containing one or more of Si 3 N 4 , BN, or AlN and having a porosity of 5% by volume or more. Since 3 N 4 , BN or AlN decomposes, the molten metal does not adhere. Further, the water injection nozzle 505 or its protection guide 506 is cooled from the inside by the cooling water 514, so that the coating layer 507 is kept at a low temperature and the decomposition of the coating layer 507 due to the temperature rise is reduced.
この技術は、水噴射ノズル５０５への溶融金属の付着を防ぎブロッキング現象を防止する上では有用である。しかし、溶融金属の飛沫の衝突により被覆層５０７が局所的に分解するから、製造される金属粉末に被覆層５０７由来の不純物が混入する。すなわち、製造される金属粉末の純度が低いので、エレクトロニクス分野の高電導度の導電性ペースト等の原料として使用することができないという欠点がある。 This technique is useful in preventing the adhesion of molten metal to the water jet nozzle 505 and preventing the blocking phenomenon. However, since the coating layer 507 is locally decomposed by the collision of molten metal droplets, impurities derived from the coating layer 507 are mixed into the manufactured metal powder. That is, since the purity of the metal powder to be produced is low, there is a drawback that it cannot be used as a raw material for conductive pastes having high conductivity in the electronics field.
溶融金属は溶湯ノズルから溶融金属柱の状態で流下する。本願発明者は後述するように、溶湯ノズル孔における目詰まりを防止したり、流下する溶融金属の揺動に起因するブロッキング現象を防止するためには、溶融金属の動粘度を小さく保つことが有効であることを発見した。 The molten metal flows down from the molten metal nozzle in a molten metal column state. As will be described later, the inventor of the present application is effective in keeping the kinematic viscosity of the molten metal small in order to prevent clogging in the molten metal nozzle hole and to prevent a blocking phenomenon caused by fluctuation of the molten metal flowing down. I found out.
図１５に示すのは、特開平８−１４３９１４号公報（特許文献５）に開示された、噴霧する高圧水の水温に応じて金属の溶湯へのＳ添加量を変化させる水アトマイズ方法を使用する装置である。この装置は、溶湯落下手段６０１と、高圧水を噴霧する噴霧ノズル６０３と、粉末回収用チャンバ６０５と、回収ポンプ６１１と、冷却タンク６０９と、クーリングタワー６１３と、再循環ポンプ６１５と、水温計６１７と、温度表示装置６１９を備える。噴霧した高圧水を回収し、再循環させて再利用するので、時間経過に伴い、噴霧される高圧水の水温が上昇して粘性が低下する。それに合わせて、金属の溶湯へのＳ添加量を低下させることで溶湯の粘度を低下させ、噴霧水の水温上昇に伴う粘度低下とのバランスを保ち、水温の影響を受けることなく、ほぼ同じ様な粉末を製造することができる。 FIG. 15 shows the use of a water atomizing method disclosed in Japanese Patent Application Laid-Open No. 8-143914 (Patent Document 5) that changes the amount of S added to a molten metal depending on the temperature of high-pressure water to be sprayed. Device. This apparatus includes a molten metal dropping means 601, a spray nozzle 603 for spraying high-pressure water, a powder recovery chamber 605, a recovery pump 611, a cooling tank 609, a cooling tower 613, a recirculation pump 615, and a water temperature meter 617. And a temperature display device 619. Since the sprayed high-pressure water is collected, recirculated and reused, the temperature of the sprayed high-pressure water rises and the viscosity decreases with time. In accordance with this, the amount of S added to the molten metal is decreased to reduce the viscosity of the molten metal, maintain a balance with the decrease in viscosity due to the increase in the water temperature of the spray water, and is almost the same without being affected by the water temperature. Powder can be produced.
特許文献５に開示された、金属の溶湯の粘度を調整するというアイデアは、溶湯ノズル孔の目詰まりの防止や、流下する溶融金属の揺動に起因するブロッキング現象の防止にも有効である。しかし、Ｓの添加量を調整することで金属の溶湯の粘度を調整するから、製造される金属粉末に不純物が混入することが避けられない。すなわち、製造される金属粉末の純度が低く、エレクトロニクス分野の高電導度の導電性ペースト等の原料として使用することができないという欠点がある。 The idea of adjusting the viscosity of the molten metal disclosed in Patent Document 5 is also effective for preventing clogging of the molten metal nozzle hole and blocking phenomenon caused by the fluctuation of the molten metal flowing down. However, since the viscosity of the molten metal is adjusted by adjusting the amount of S added, it is inevitable that impurities are mixed into the manufactured metal powder. That is, there is a drawback that the purity of the metal powder to be produced is low and the metal powder cannot be used as a raw material for a highly conductive conductive paste in the electronics field.
特許文献１に開示された金属粉末製造装置は、溶融金属柱に衝突した後の噴霧水の進路を変更する進路変更手段を有し、アモルファス化が進行した金属粉末を得ることができるが、エレクトロニクス分野における高電導度の導電性ペースト等の原材料に適した、結晶化の進行した金属粉末を得ることはできない。
又、特許文献１に開示された従来の環状の噴霧ノズルの構成では、液体ジェットに生じた周方向の乱れや時間的な変動が減衰しにくく、全周均一に途切れなく安定して水を噴霧することが困難である。
特許文献２に開示された金属粉末の製造方法は、噴霧ノズルの噴射出口から上方側の壁面に沿って付着防止用流体を流すことにより金属粉末の壁面への付着を防止することを意図しているが、気流で付着防止用流体が吹き飛ばされて壁面が露出した場合や、多量の溶融金属が壁面に触れて接触した場合の焼付を防止できない。
特許文献３に開示された金属粉末の製造方法は、噴霧ノズルの内壁面を、溶融金属との接触角が９０°〜１８０°の濡れ性を有する材質により構成することで、溶融金属の飛沫が内壁面に付着することを防止することを意図しているが、現実の内壁面は微細な凹凸を有し、局所的に接触角が９０°未満となる領域が生じて、そのような領域に溶融金属４００Ｍが付着・堆積し、やがてはブロッキング現象へと発展する事象がしばしば起きる欠点がある。
特許文献４に開示されたブロッキング現象の防止方法は、水噴射ノズル等の表面に、溶
融金属の飛沫が接触すると分解する耐火材料からなる被覆層を構成し、更に水噴射ノズル等を冷却することで、溶融金属の飛沫の付着閉塞（ブロッキング現象）を防止することを意図しているが、製造される金属粉末に分解した被覆層由来の不純物が混入するため、エレクトロニクス分野の高電導度の導電性ペースト等の原料に適した高純度の金属粉末を得ることができない。
特許文献５に開示された合金鋼粉末の製造方法は、噴霧水の水温に応じてＳの添加量を調整することで金属の溶湯の粘度を調整し、安定した品質の金属粉末を得ることを意図したものであるが、Ｓを溶湯に添加するから、製造される金属粉末に不純物が混入することが避けられず、エレクトロニクス分野の高電導度の導電性ペースト等の原料に適した高純度の金属粉末を得ることができないという欠点がある。
The metal powder manufacturing apparatus disclosed in Patent Document 1 has a course changing means for changing the course of spray water after colliding with a molten metal column, and can obtain a metal powder that has undergone amorphization. It is not possible to obtain a metal powder having undergone crystallization suitable for raw materials such as conductive paste having a high conductivity in the field.
Further, in the configuration of the conventional annular spray nozzle disclosed in Patent Document 1, circumferential disturbance and temporal fluctuation generated in the liquid jet are not easily attenuated, and water is sprayed stably and uniformly over the entire circumference. Difficult to do.
The manufacturing method of the metal powder disclosed in Patent Document 2 intends to prevent the adhesion of the metal powder to the wall surface by flowing an adhesion preventing fluid along the upper wall surface from the spray outlet of the spray nozzle. However, seizure cannot be prevented when the adhesion preventing fluid is blown off by the air flow and the wall surface is exposed, or when a large amount of molten metal touches and contacts the wall surface.
In the method for producing metal powder disclosed in Patent Document 3, the inner wall surface of the spray nozzle is made of a material having a wettability with a contact angle with the molten metal of 90 ° to 180 °, so that the molten metal splashes. Although it is intended to prevent adhesion to the inner wall surface, the actual inner wall surface has fine irregularities, and a region where the contact angle is less than 90 ° is generated locally. There is a drawback that an event that the molten metal 400M adheres and accumulates and eventually develops into a blocking phenomenon often occurs.
The method for preventing the blocking phenomenon disclosed in Patent Document 4 is to form a coating layer made of a refractory material that decomposes when the molten metal droplets come into contact with the surface of the water injection nozzle and the like, and further cool the water injection nozzle and the like However, it is intended to prevent adhesion and blockage (blocking phenomenon) of molten metal droplets, but because the metal powder produced is mixed with impurities from the decomposed coating layer, it has high conductivity in the electronics field. High-purity metal powder suitable for raw materials such as adhesive paste cannot be obtained.
The manufacturing method of the alloy steel powder disclosed in Patent Document 5 is to adjust the viscosity of the molten metal by adjusting the amount of S added according to the water temperature of the spray water to obtain a stable quality metal powder. As intended, since S is added to the molten metal, it is inevitable that impurities are mixed into the metal powder to be manufactured, and it has a high purity suitable for a raw material such as a highly conductive conductive paste in the electronics field. There is a disadvantage that metal powder cannot be obtained.
本願発明の目的は、生産効率が高く、溶湯ノズル孔の目詰まりやブロッキング現象を起こさないので長時間の安定稼働ができ、エレクトロニクス分野の高電導度の導電性ペースト等の原料に適した高純度の銀粉末を得ることのできる銀粉末製造方法及び銀粉末製造装置を提供することである。 The purpose of the present invention is high purity, suitable for raw materials such as high-conductivity conductive paste in the electronics field, because it has high production efficiency, does not cause clogging or blocking phenomenon of the molten metal nozzle hole, and can operate stably for a long time. It is providing the silver powder manufacturing method and silver powder manufacturing apparatus which can obtain silver powder of this.
本願発明は上記課題を解決するためになされたものであり、本願発明の第１の形態は、溶融銀を溶融銀柱の状態で流下させ、前記溶融銀柱が中心軸となるように配置された環状の噴霧ノズルから水を前記溶融銀柱に噴霧して、前記溶融銀を微粒子化する工程を少なくとも有する銀粉末製造方法であり、前記水は略逆円錐面に沿ってその頂部である第１収束部に収束するように噴霧され、前記頂部の位置を前記溶融銀柱の内部に設定して、前記第１収束部において前記溶融銀を微粒子化し、前記第１収束部を経た前記水は略円錐面に沿って進行し、軸対称な吸引管の内面の第１円環部に当たって反射し、第２略逆円錐面に沿ってその頂部である第２収束部に収束するように進行し、前記第２収束部において、前記第１収束部で微粒子化されなかった前記溶融銀柱の溶融銀を微粒子化し、及び／又は、前記第１収束部で微粒子化により生成した銀粒子を更に粉砕して微粒子化することを特徴とする銀粉末製造方法である。 The present invention has been made in order to solve the above-mentioned problems, and the first aspect of the present invention is arranged such that molten silver flows down in the form of a molten silver column, and the molten silver column is the central axis. A method for producing silver powder comprising at least a step of atomizing the molten silver by spraying water onto the molten silver column from an annular spray nozzle, wherein the water is a top portion substantially along an inverted conical surface. Sprayed so as to converge on one converging part, the position of the top is set inside the molten silver column, the molten silver is atomized in the first converging part, and the water that has passed through the first converging part is Proceeds along a substantially conical surface, reflects against the first annular portion of the inner surface of the axisymmetric suction pipe, and proceeds so as to converge along the second substantially inverted conical surface to the second converging portion at the top. In the second converging part, the first converging part is not atomized. The molten silver molten silver pillar micronized with, and / or a silver powder manufacturing method characterized by further pulverizing into fine particles by the silver particles produced by atomization by the first converging portion.
本願発明の第２の形態は、前記水を、いずれも内縁側ほど上方に湾曲した２つの円環面で挟まれた間隙を流路として、外縁側から内縁側に向けて進行させた後、円環状反射面に当てて下方に向けて反射することで、前記水が前記略逆円錐面に沿って全周途切れなく噴霧され、前記間隙を画成する２つの円環面の間隔は内縁側に向かって減少する銀粉末製造方法である。 In the second aspect of the present invention, the water is allowed to travel from the outer edge side toward the inner edge side, with the gap sandwiched between the two annular surfaces curved upward toward the inner edge side. The water is sprayed without any interruption along the substantially inverted conical surface by being reflected downwardly against the annular reflecting surface, and the interval between the two annular surfaces defining the gap is the inner edge side. This is a method for producing silver powder that decreases toward.
本願発明の第３の形態は、前記略逆円錐面の頂角の大きさをθとしたとき２５°≦θ≦３０°が成立し、前記第２収束部が前記吸引管の下端より上方に位置するように、前記吸引管の径及び長さが設定される銀粉末製造方法である。 In the third aspect of the present invention, 25 ° ≦ θ ≦ 30 ° is established when the apex angle of the substantially inverted conical surface is θ, and the second converging portion is located above the lower end of the suction pipe. It is the silver powder manufacturing method by which the diameter and length of the said suction tube are set so that it may be located.
本願発明の第４の形態は、前記噴霧ノズルの前記溶融銀柱に対向する表面であって、流下する前記溶融銀に向かい合う表面に硬質炭素薄膜を形成し、前記硬質炭素薄膜はダイヤモンド薄膜又はＤＬＣ膜であり、更に前記硬質炭素薄膜の表面に水を流すことにより水膜を形成して、前記硬質炭素薄膜への銀の付着とブロッキング現象を防止する銀粉末製造方法である。 According to a fourth aspect of the present invention, a hard carbon thin film is formed on the surface of the spray nozzle facing the molten silver column and facing the molten silver flowing down, and the hard carbon thin film is a diamond thin film or DLC. The silver powder manufacturing method further comprises forming a water film by flowing water over the surface of the hard carbon thin film to prevent adhesion of silver to the hard carbon thin film and blocking phenomenon.
本願発明の第５の形態は、前記溶融銀が溶湯ノズルから流下し、前記溶融銀の温度を１４００℃以上１６００℃以下とすることで、前記溶融銀の動粘度を０．２２ｍｍ２／ｓ以下に低下させて前記溶湯ノズルの目詰まりとブロッキング現象を防止し、製造される銀粉末の粒径を小さくする銀粉末製造方法である。 According to a fifth aspect of the present invention, the molten silver flows down from the molten metal nozzle, and the temperature of the molten silver is 1400 ° C. or higher and 1600 ° C. or lower, so that the kinematic viscosity of the molten silver is 0.22 mm 2 / s or lower. The silver powder manufacturing method reduces the particle size of the silver powder to be manufactured by preventing clogging and blocking phenomenon of the molten metal nozzle.
本願発明の第６の形態は、前記溶湯ノズル孔の直径が１ｍｍ以上３ｍｍ以下であり、前記溶融銀が流下する平均質量流量が０．５ｋｇ／ｍｉｎ以上４．５ｋｇ／ｍｉｎ以下であり、前記溶湯ノズル孔の直径が小さいほど製造される銀粉末の粒径が小さくなる銀粉末製造方法である。 In the sixth aspect of the present invention, the diameter of the melt nozzle hole is 1 mm or more and 3 mm or less, the average mass flow rate at which the molten silver flows down is 0.5 kg / min or more and 4.5 kg / min or less, This is a silver powder production method in which the particle diameter of the silver powder produced becomes smaller as the diameter of the nozzle hole becomes smaller.
本願発明の第７の形態は、前記溶湯ノズルの材質が窒化アルミニウム、窒化ケイ素、窒化ホウ素、炭化ケイ素、酸化マグネシウム、酸化アルミニウムのいずれかであり、好ましくは窒化アルミニウム又は窒化ケイ素であり、更に好ましくは窒化ケイ素である銀粉末製造方法である。 In a seventh aspect of the present invention, the material of the molten metal nozzle is any one of aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, and aluminum oxide, preferably aluminum nitride or silicon nitride, and more preferably Is a method for producing silver powder which is silicon nitride.
本願発明の第８の形態は、水から脱イオン水を製造するための脱イオン工程を有し、前記水として脱イオン水を噴霧することで製造される銀粉末の純度を高くする銀粉末製造方法である。 The eighth aspect of the present invention is a silver powder production process having a deionization step for producing deionized water from water, and increasing the purity of the silver powder produced by spraying deionized water as the water. Is the method.
本願発明の第９の形態は、溶融銀を溶融銀柱の状態で流下させるための溶湯ノズルと、水を略逆円錐面に沿ってその頂部である第１収束部に収束するように噴霧するための噴霧ノズルと、前記頂部の位置を前記溶融銀柱の内部に設定する水平位置調整手段を少なくとも有する銀粉末製造装置であり、前記噴霧ノズルは軸対称な吸引管を有し、前記吸引管の径及び長さは、噴霧された前記水が前記第１収束部において前記溶融銀を微粒子化し、前記第１収束部を経た前記水が略円錐面に沿って進行し、前記吸引管の内面の第１円環部に当たって反射し、第２略逆円錐面に沿ってその頂部である第２収束部に向かって進行するように設定されることを特徴とする銀粉末製造装置である。 In the ninth aspect of the present invention, a molten metal nozzle for causing molten silver to flow down in the state of a molten silver column, and water are sprayed so as to converge along a substantially inverted conical surface to the first converging portion which is the top portion thereof. A silver powder producing apparatus having at least a horizontal position adjusting means for setting a position of the top portion inside the molten silver column, the spray nozzle having an axisymmetric suction pipe, and the suction pipe The sprayed water atomizes the molten silver in the first converging part, the water passing through the first converging part travels along a substantially conical surface, and the inner surface of the suction pipe The silver powder production apparatus is characterized in that it is set so as to be reflected by hitting the first annular portion and to proceed toward the second converging portion which is the top portion along the second substantially inverted conical surface.
本願発明の第１０の形態は、前記噴霧ノズルは、離間して対面する上側環状部材と下側環状部材からなり、前記水は、両環状部材で挟まれた間隙を流路として両環状部材の外縁側から内縁側へ向かって進行し、互いに対面する前記下側環状部材の上面と、最内縁部を除く前記上側環状部材の下面はいずれも、少なくともそれらの内縁部において内縁側ほど上方に湾曲した円環面の形状を有し、前記間隙を画成する２つの前記円環面の間隔は内縁側に向かって減少し、前記上側環状部材の下面の前記最内縁部は、前記上側環状部材に係る前記円環面の上縁部と段差なく接続する円環状反射面であり、前記流路を進行した前記水を、前記円環状反射面に当てて下方に向けて反射することで、前記水が前記略逆円錐面に沿って前記第１収束部に収束するように全周途切れなく噴霧される銀粉末製造装置である。 In a tenth aspect of the present invention, the spray nozzle is composed of an upper annular member and a lower annular member facing each other at a distance, and the water is formed between the annular members using a gap between the annular members as a flow path. The upper surface of the lower annular member that proceeds from the outer edge side toward the inner edge side and faces each other, and the lower surface of the upper annular member excluding the innermost edge portion are curved upward toward the inner edge side at least at the inner edge portion. The space between the two annular surfaces defining the gap decreases toward the inner edge side, and the innermost edge portion of the lower surface of the upper annular member is the upper annular member. The annular reflection surface connected to the upper edge portion of the annular surface without any step, and the water that has traveled through the flow path is reflected downwardly against the annular reflection surface, Water converges on the first converging portion along the substantially inverted conical surface Silver powder production apparatus to be sprayed seamlessly entire circumference so that.
本願発明の第１１の形態は、前記略逆円錐面の頂角の大きさをθとしたとき２５°≦θ≦３０°が成立し、前記第２収束部が前記吸引管の下端より上方に位置するように、前記吸引管の径及び長さが設定される銀粉末製造装置である。 In an eleventh aspect of the present invention, 25 ° ≦ θ ≦ 30 ° is established when the apex angle of the substantially inverted conical surface is θ, and the second converging portion is located above the lower end of the suction pipe. It is a silver powder manufacturing apparatus by which the diameter and length of the said suction pipe are set so that it may be located.
本願発明の第１２の形態は、前記噴霧ノズルの前記溶融銀柱に対向する表面であって、流下する前記溶融銀に向かい合う表面は硬質炭素薄膜で被覆され、前記硬質炭素薄膜はダイヤモンド薄膜又はＤＬＣ膜であり、更に前記硬質炭素薄膜の表面は流水による水膜で被覆され、前記硬質炭素薄膜への銀の付着とブロッキング現象を防止する銀粉末製造装置である。 According to a twelfth aspect of the present invention, the surface of the spray nozzle facing the molten silver column, the surface facing the molten silver flowing down is coated with a hard carbon thin film, and the hard carbon thin film is a diamond thin film or DLC. The silver powder manufacturing apparatus is a film, and the surface of the hard carbon thin film is further coated with a water film of running water to prevent silver adhesion and blocking phenomenon on the hard carbon thin film.
本願発明の第１３の形態は、銀を加熱して溶融銀とするための加熱手段と、前記溶融銀の温度を調節するための温度制御手段を少なくとも有し、前記溶融銀の温度を１４００℃以上１６００℃以下とすることで、前記溶融銀の動粘度を０．２２ｍｍ２／ｓ以下に低下させて前記溶湯ノズルの目詰まりとブロッキング現象を防止し、製造される銀粉末の粒径を小さくする銀粉末製造装置である。 A thirteenth aspect of the present invention has at least heating means for heating silver to form molten silver and temperature control means for adjusting the temperature of the molten silver, and the temperature of the molten silver is 1400 ° C. By setting the temperature to 1600 ° C. or less, the kinematic viscosity of the molten silver is reduced to 0.22 mm 2 / s or less to prevent clogging and blocking phenomenon of the molten metal nozzle, and to reduce the particle size of the silver powder produced. This is a silver powder manufacturing apparatus.
本願発明の第１４の形態は、前記溶湯ノズル孔の直径が１ｍｍ以上３ｍｍ以下であり、前記溶融銀が流下する平均質量流量が０．５ｋｇ／ｍｉｎ以上４．５ｋｇ／ｍｉｎ以下であり、前記溶湯ノズル孔の直径が小さいほど製造される銀粉末の粒径が小さくなる銀粉末製造装置である。 In a fourteenth aspect of the present invention, the diameter of the molten metal nozzle hole is 1 mm or more and 3 mm or less, the average mass flow rate at which the molten silver flows down is 0.5 kg / min or more and 4.5 kg / min or less, This is a silver powder production apparatus in which the particle diameter of the silver powder produced becomes smaller as the diameter of the nozzle hole becomes smaller.
本願発明の第１５の形態は、前記溶湯ノズルの材質が窒化アルミニウム、窒化ケイ素、窒化ホウ素、炭化ケイ素、酸化マグネシウム、酸化アルミニウムのいずれかであり、好ましくは窒化アルミニウム又は窒化ケイ素であり、更に好ましくは窒化ケイ素である銀粉末製造装置である。 In a fifteenth aspect of the present invention, the material of the molten metal nozzle is any one of aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, and aluminum oxide, preferably aluminum nitride or silicon nitride, and more preferably Is a silver powder production apparatus which is silicon nitride.
本願発明の第１６の形態は、水から脱イオン水を製造するための脱イオン装置を有し、前記水として脱イオン水を噴霧することで製造される銀粉末の純度を高くする銀粉末製造装置である。 A sixteenth aspect of the present invention is a silver powder production which has a deionization device for producing deionized water from water and increases the purity of the silver powder produced by spraying deionized water as the water. Device.
本願発明の第１の形態によれば、溶融銀を２箇所で微粒子化することにより、効率良く銀粉末を製造することができる銀粉末製造方法を提供できる。 According to the 1st form of this invention, the silver powder manufacturing method which can manufacture silver powder efficiently can be provided by atomizing molten silver in two places.
すなわち本形態によれば、溶融銀柱が中心軸となるように配置された環状の噴霧ノズルから、水が略逆円錐面に沿ってその頂部である第１収束部に収束するように噴霧され、前記第１収束部において前記溶融銀を微粒子化し、前記第１収束部を経た前記水は略円錐面に沿って進行し、軸対称な吸引管の内面の第１円環部に当たって反射し、第２略逆円錐面に沿ってその頂部である第２収束部に収束するように進行し、前記第２収束部において、前記第１収束部で微粒子化されなかった前記溶融銀柱の溶融銀を微粒子化し、及び／又は、前記第１収束部で微粒子化により生成した銀粒子を更に粉砕して微粒子化するから、ブロッキング現象防止のために前記略逆円錐面の頂角を小さく設定したとしても、高い生産効率で銀粉末を製造することができる。 That is, according to the present embodiment, water is sprayed from the annular spray nozzle arranged so that the molten silver column becomes the central axis so as to converge on the first converging portion that is the top along the substantially inverted conical surface. In the first converging part, the molten silver is finely divided, and the water passing through the first converging part travels along a substantially conical surface, hits the first annular part on the inner surface of the axisymmetric suction pipe, and is reflected. The molten silver of the molten silver column proceeds along the second substantially inverted conical surface so as to converge at the second converging portion, which is the top of the conical surface, and is not atomized by the first converging portion in the second converging portion. Since the silver particles produced by the fine particles at the first converging part are further pulverized into fine particles, the apex angle of the substantially inverted conical surface is set small to prevent blocking phenomenon. Can produce silver powder with high production efficiency Kill.
本願発明の第２の形態によれば、水を、いずれも内縁側ほど上方に湾曲した２つの円環面で挟まれた間隙を流路として、外縁側から内縁側に向けて進行させた後、円環状反射面に当てて下方に向けて反射し、前記間隙を画成する２つの円環面の間隔は内縁側に向かって減少するから、前記水を前記略逆円錐面に沿って全周途切れなく噴霧することができる。水が全周途切れなく噴霧され、周方向にほぼ一様に噴霧されるから、噴霧水が溶融銀柱に及ぼす力積のベクトル和がほぼゼロとなり、溶融銀柱の揺動や吸い込み気流の乱れに起因するブロッキング現象の発生を抑制することができる銀粉末製造方法を提供できる。 According to the second aspect of the present invention, after water has progressed from the outer edge side toward the inner edge side, using a gap sandwiched between two annular surfaces curved upward as the inner edge side as a flow path. Since the distance between the two annular surfaces that are reflected downwardly against the annular reflecting surface and that defines the gap decreases toward the inner edge side, the water is completely removed along the substantially inverted conical surface. Can be sprayed without interruption. Since the water is sprayed all the way around and is sprayed almost uniformly in the circumferential direction, the vector sum of the impulses exerted on the molten silver column by the sprayed water becomes almost zero, causing fluctuations in the molten silver column and disturbance of the suction airflow. The silver powder manufacturing method which can suppress generation | occurrence | production of the blocking phenomenon resulting from this can be provided.
本願発明者等は、水を一度、円環状反射面に当てて下方に向けて反射する構成を採用することで、水を全周途切れなくほぼ均一に噴霧可能であることを見出した。その理由は定かではないが、水が内縁側に向かってその間隔が減少する２つの円環面の間を重力に逆らって斜め上向きに上昇する際に、水の速度の周方向の非一様成分や時間変動成分が減衰すること、及び、水が円環状反射面に当たって反射する際に、水の速度の周方向の非一様性や時間的な変動が平均化・均一化されて、水を全周途切れなくほぼ均一に噴霧することができるものと思量する。 The inventors of the present application have found that water can be sprayed almost uniformly without any interruption in the entire circumference by adopting a configuration in which water is once applied to the annular reflecting surface and reflected downward. The reason for this is not clear, but when the water rises diagonally upward against the gravity between the two annular surfaces whose distance decreases toward the inner edge, the circumferential velocity of the water is not uniform. When the component and time-varying component are attenuated, and when the water hits the annular reflecting surface and is reflected, the non-uniformity in the circumferential direction of the water velocity and the temporal variation are averaged and uniformed. It is assumed that the spray can be sprayed almost uniformly without any interruption.
本願発明の第３の形態によれば、前記略逆円錐面の頂角の大きさθを２５°≦θ≦３０°を満たす小さな角に設定するから、噴霧水の衝撃を受けて溶融銀が吹き上げることに起因するブロッキング現象が発生しにくく、かつ、溶融銀を第１収束部と第２収束部の２箇所で粉砕して溶融銀を微粒子化するから、生産効率の高い銀粉末製造方法を提供できる。本形態においては、吸引管の形状（径及び長さ）が、前記第２収束部が前記吸引管の下端より上方に位置するように設定されるから、吸引管内で吸い込み気流の乱れが生じにくく
、噴霧水の揺動や溶融銀柱の揺動に起因するブロッキング現象の発生を抑制することができる。
According to the third aspect of the present invention, since the apex angle size θ of the substantially inverted conical surface is set to a small angle satisfying 25 ° ≦ θ ≦ 30 °, the molten silver is affected by the impact of spray water. A blocking phenomenon caused by blowing up is unlikely to occur, and the molten silver is pulverized at two locations of the first converging part and the second converging part to make the molten silver fine particles. Can be provided. In this embodiment, since the shape (diameter and length) of the suction tube is set so that the second converging portion is located above the lower end of the suction tube, the suction airflow is not easily disturbed in the suction tube. Further, it is possible to suppress the occurrence of the blocking phenomenon caused by the fluctuation of the spray water and the fluctuation of the molten silver column.
更に、本形態の変形例においては、吸引管の形状（径及び長さ）が、第２収束部を経た水が第２略円錐面に沿って進行し、吸引管の内面の第２円環部に当たるように設定されるから、吸引管内で吸い込み気流の乱れが生じにくく、噴霧水の揺動や溶融銀柱の揺動に起因するブロッキング現象の発生をより確実に防止することができる。 Further, in the modification of the present embodiment, the shape (diameter and length) of the suction tube is such that the water that has passed through the second converging portion travels along the second substantially conical surface, and the second annular ring on the inner surface of the suction tube Therefore, the disturbance of the suction air flow hardly occurs in the suction pipe, and the occurrence of the blocking phenomenon due to the fluctuation of the spray water and the fluctuation of the molten silver column can be more reliably prevented.
本願発明の第４の形態によれば、噴霧ノズルの溶融銀柱に対向する表面であって、流下する溶融銀に向かい合う表面に硬質炭素薄膜を形成し、前記硬質炭素薄膜はダイヤモンド薄膜又はＤＬＣ膜であり、更に前記硬質炭素薄膜の表面に水を流すことにより水膜を形成するから、前記硬質炭素薄膜への銀の付着とブロッキング現象を防止する銀粉末製造方法を提供できる。 According to the fourth aspect of the present invention, a hard carbon thin film is formed on the surface of the spray nozzle facing the molten silver column and facing the flowing molten silver, and the hard carbon thin film is a diamond thin film or a DLC film. Furthermore, since a water film is formed by flowing water over the surface of the hard carbon thin film, a silver powder production method for preventing silver adhesion and blocking phenomenon on the hard carbon thin film can be provided.
硬質炭素薄膜と溶融銀の接触角は９０°〜１８０°の範囲にあるため、硬質炭素薄膜は溶融銀に対して濡れない性質を有する。又、噴霧ノズルの表面にＣＶＤ、ＰＶＤ、メッキ、スパッタリング等の方法で硬質炭素薄膜を形成し、その表面を微視的にも平坦に形成することが可能であるから、溶融銀の飛沫が接触しても付着・堆積は起こりにくい。しかし、多量の溶融銀の飛沫が接触して焼付を起こすと硬質炭素薄膜が昇温により脆弱となって剥離し、剥離部分から溶融銀の付着・堆積が進行してブロッキング現象を引き起こすおそれがある。そこで、接触する溶融銀の飛沫を洗い流し、かつ硬質炭素薄膜を冷却する目的で、その表面に水膜を形成するものである。 Since the contact angle between the hard carbon thin film and the molten silver is in the range of 90 ° to 180 °, the hard carbon thin film has a property that it does not wet the molten silver. In addition, a hard carbon thin film can be formed on the surface of the spray nozzle by CVD, PVD, plating, sputtering, etc., and the surface can be microscopically flat. However, adhesion and accumulation are unlikely to occur. However, if a large amount of molten silver droplets come into contact with each other and cause baking, the hard carbon thin film becomes brittle and peels due to the temperature rise, and adhesion and deposition of molten silver may progress from the peeled portion, causing a blocking phenomenon. . Therefore, a water film is formed on the surface for the purpose of washing away the splash of molten silver and cooling the hard carbon thin film.
本願発明の第５の形態によれば、溶融銀の温度を１４００℃以上１６００℃以下とすることで、溶融銀の動粘度を０．２２ｍｍ２／ｓ以下に低下させて、溶湯ノズル孔からの銀の溶湯のスムーズな流れ出しを実現し、溶湯ノズル孔の目詰まりとブロッキング現象を防止し、製造される銀粉末の粒径を小さくする銀粉末製造方法を提供できる。 According to the fifth aspect of the present invention, by setting the temperature of the molten silver to 1400 ° C. or more and 1600 ° C. or less, the kinematic viscosity of the molten silver is reduced to 0.22 mm 2 / s or less, and from the melt nozzle hole It is possible to provide a method for producing a silver powder that realizes a smooth flow of molten silver, prevents clogging and blocking phenomenon of a molten metal nozzle hole, and reduces the particle diameter of the produced silver powder.
溶融銀の温度は、銀の融点（９６２℃）から１６００℃の範囲であればどの温度であってもよいが、ブロッキング現象を起こさずにアトマイズするには１４００℃から１６００℃の範囲が好ましい。
何故ならば、溶融銀の温度が１３００℃未満では、溶湯ノズルの材質によらず、溶湯ノズル孔から銀の溶湯がスムーズに流れ出さない故、上記温度は１３００℃以上とすることが望ましいが、更に溶湯ノズル孔の目詰まりやブロッキング現象を防止するためには、溶融銀の動粘度が０．２２ｍｍ２／ｓ以下となる１４００℃以上の温度が望ましい。（溶融銀の粘度の温度依存性については「溶融合金の粘度推定式」平居正純 鉄と鋼 8巻p.399-406 (1992)を参照。）又、溶融銀の温度が１６００℃を超えると、溶融銀を保持する黒鉛るつぼの支持部材等の高温耐性を維持するためのコストが無視できなくなる故、１６００℃以下の温度が望ましいからである。
尚、他の条件が同じであれば、溶融銀の動粘度が小さいほど、製造される銀粉末の粒径分布は粒径が小さい方へとシフトし、平均粒径及び粒径の最頻値は小さくなる。
The temperature of the molten silver may be any temperature as long as it is in the range of 1600 ° C. from the melting point of silver (962 ° C.), but is preferably in the range of 1400 ° C. to 1600 ° C. for atomization without causing a blocking phenomenon.
This is because if the temperature of the molten silver is less than 1300 ° C., the molten silver does not flow smoothly from the molten nozzle hole regardless of the material of the molten metal nozzle, so the above temperature is preferably 1300 ° C. or higher. Further, in order to prevent clogging of the molten metal nozzle hole and blocking phenomenon, a temperature of 1400 ° C. or higher at which the kinematic viscosity of molten silver is 0.22 mm 2 / s or lower is desirable. (For the temperature dependence of the viscosity of molten silver, see “Viscosity Estimation Formula for Molten Alloys” Masami Hirai Iron and Steel, Vol. 8, pages 399-406 (1992).) When the temperature of molten silver exceeds 1600 ° C This is because a temperature of 1600 ° C. or lower is desirable because the cost for maintaining the high temperature resistance of the support member for the graphite crucible for holding the molten silver cannot be ignored.
If the other conditions are the same, the smaller the kinematic viscosity of the molten silver, the smaller the particle size distribution of the silver powder produced, the smaller the particle size, and the mean value of the average particle size and particle size. Becomes smaller.
本願発明の第６の形態によれば、溶湯ノズル孔の直径が１ｍｍ以上３ｍｍ以下であり、溶融銀が流下する平均質量流量が０．５ｋｇ／ｍｉｎ以上４．５ｋｇ／ｍｉｎ以下であり、溶湯ノズル孔の直径が小さいほど製造される銀粉末の粒径が小さくなる銀粉末製造方法を提供できる。 According to the sixth aspect of the present invention, the diameter of the melt nozzle hole is 1 mm or more and 3 mm or less, the average mass flow rate at which the molten silver flows down is 0.5 kg / min or more and 4.5 kg / min or less, and the melt nozzle The silver powder manufacturing method with which the particle size of the silver powder manufactured as the diameter of a hole becomes small can be provided.
本形態においては、噴霧水により第１収束部と第２収束部の２箇所で溶融銀を効率よく粉砕して銀粉末を製造できるので、ブロッキング現象防止のために前記略逆円錐面の頂角を小さく設定したとしても、溶湯ノズル孔の直径を上記範囲内に設定し、０．５ｋｇ／ｍ
ｉｎ以上４．５ｋｇ／ｍｉｎ以下の比較的大きな平均質量流量で溶融銀を流下させて、短時間に多量の銀粉末を製造することができる。又、上記範囲内で、より小さな溶湯ノズル孔の直径を選択することにより、製造される銀粉末の平均粒径を小さくすることができる。
In this embodiment, the silver powder can be produced by efficiently pulverizing the molten silver at two locations of the first converging part and the second converging part with spray water, so that the vertex angle of the substantially inverted conical surface is used to prevent the blocking phenomenon. Is set to a small value, the diameter of the molten metal nozzle hole is set within the above range, and 0.5 kg / m
A large amount of silver powder can be produced in a short time by flowing molten silver at a relatively large average mass flow rate of in or more and 4.5 kg / min or less. Moreover, the average particle diameter of the silver powder manufactured can be made small by selecting the diameter of a smaller molten metal nozzle hole within the said range.
本願発明の第７の形態によれば、溶湯ノズルの材質が窒化アルミニウム、窒化ケイ素、窒化ホウ素、炭化ケイ素、酸化マグネシウム、酸化アルミニウムのいずれかであり、好ましくは窒化アルミニウム又は窒化ケイ素であり、更に好ましくは窒化ケイ素である銀粉末製造方法を提供できる。 According to the seventh aspect of the present invention, the material of the molten metal nozzle is any one of aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, and aluminum oxide, preferably aluminum nitride or silicon nitride, A method for producing silver powder, preferably silicon nitride, can be provided.
溶湯ノズル孔における銀の溶湯の目詰まりを防止するためには、熱伝導率の大きな材質で溶湯ノズルを構成することが望ましい。そこで、セラミックス製のノズル材質として最も熱伝導率の高い窒化アルミニウムが望まれる。しかし、窒化アルミニウムはウルツ鉱型結晶特有の熱膨張が起こるために、使用中に脆性破壊する欠点がある。そこで、熱伝導率が高く、且つ、脆性破壊が起こらない窒化ケイ素がノズル素材として適している。その他、溶湯ノズルの材質として、炭化ケイ素、窒化ホウ素、酸化アルミニウム、酸化マグネシウム等を用いてもよい。 In order to prevent clogging of the molten silver in the molten metal nozzle hole, it is desirable to configure the molten metal nozzle with a material having a high thermal conductivity. Therefore, aluminum nitride having the highest thermal conductivity is desired as a ceramic nozzle material. However, aluminum nitride has a drawback of brittle fracture during use because of the thermal expansion specific to wurtzite crystals. Accordingly, silicon nitride that has high thermal conductivity and does not cause brittle fracture is suitable as a nozzle material. In addition, silicon carbide, boron nitride, aluminum oxide, magnesium oxide, or the like may be used as the material for the molten metal nozzle.
本願発明の第８の形態によれば、水から脱イオン水を製造するための脱イオン工程を有し、前記水として脱イオン水を噴霧することで製造される銀粉末の純度を高くする銀粉末製造方法を提供できる。本形態の製造方法によれば、不純物が少なく、エレクトロニクス分野の用途に適した銀粉末を製造することができる。 According to the 8th form of this invention, it has the deionization process for manufacturing deionized water from water, Silver which raises the purity of the silver powder manufactured by spraying deionized water as said water A powder manufacturing method can be provided. According to the manufacturing method of this embodiment, it is possible to manufacture a silver powder that has few impurities and is suitable for applications in the electronics field.
本願発明の第９の形態によれば、流下する溶融銀柱に噴霧ノズルから水を噴霧して、溶融銀を第１収束部と第２収束部の２箇所で微粒子化することにより、高い生産効率で銀粉末を製造することができる銀粉末製造装置を提供できる。 According to the ninth aspect of the present invention, high production is achieved by spraying water from a spray nozzle onto the flowing molten silver column and atomizing the molten silver at two locations of the first converging part and the second converging part. A silver powder production apparatus capable of producing silver powder with efficiency can be provided.
本願発明の第１０の形態によれば、水を、いずれも内縁側ほど上方に湾曲した２つの円環面で挟まれた間隙を流路として、外縁側から内縁側に向けて進行させた後、円環状反射面に当てて下方に向けて反射し、前記間隙を画成する２つの円環面の間隔は内縁側に向かって減少するように構成した噴霧ノズルを用いることにより、前記水を前記略逆円錐面に沿って全周途切れなく噴霧し、溶融銀柱の揺動や吸い込み気流の乱れに起因するブロッキング現象の発生を抑制する銀粉末製造装置を提供できる。 According to the tenth aspect of the present invention, after water has progressed from the outer edge side toward the inner edge side, with a gap sandwiched between two annular surfaces curved upwards toward the inner edge side. The water is reflected by using a spray nozzle configured to be applied to the annular reflecting surface and reflected downward and the distance between the two annular surfaces defining the gap to decrease toward the inner edge side. It is possible to provide a silver powder production apparatus that sprays along the substantially inverted conical surface without any interruption, and suppresses the occurrence of a blocking phenomenon caused by the fluctuation of the molten silver column and the disturbance of the suction airflow.
本願発明の第１１の形態によれば、前記略逆円錐面の頂角の大きさθを２５°≦θ≦３０°を満たす小さな角に設定するからブロッキング現象が発生しにくく、かつ、溶融銀を第１収束部と第２収束部の２箇所で粉砕して溶融銀を効率よく微粒子化するから、生産効率の高い銀粉末製造装置を提供できる。本形態においては、吸引管の形状（径及び長さ）が、前記第２収束部が前記吸引管の下端より上方に位置するように設定されるから、吸引管内で吸い込み気流の乱れが生じにくく、ブロッキング現象の発生を抑制することができる。 According to the eleventh aspect of the present invention, since the magnitude θ of the apex angle of the substantially inverted conical surface is set to a small angle satisfying 25 ° ≦ θ ≦ 30 °, the blocking phenomenon is unlikely to occur, and the molten silver Is pulverized at two locations of the first converging unit and the second converging unit to efficiently atomize the molten silver, so that a silver powder production apparatus with high production efficiency can be provided. In this embodiment, since the shape (diameter and length) of the suction tube is set so that the second converging portion is located above the lower end of the suction tube, the suction airflow is not easily disturbed in the suction tube. The occurrence of the blocking phenomenon can be suppressed.
本形態の変形例においては、吸引管の形状（径及び長さ）が、第２収束部を経た水が第２略円錐面に沿って進行し、吸引管の内面の第２円環部に当たるように設定されるから、吸引管内で吸い込み気流の乱れが生じにくく、ブロッキング現象の発生をより確実に防止することができる。 In the modification of the present embodiment, the shape (diameter and length) of the suction tube is such that the water that has passed through the second converging portion travels along the second substantially conical surface and hits the second annular portion on the inner surface of the suction tube. Therefore, the disturbance of the suction airflow hardly occurs in the suction pipe, and the occurrence of the blocking phenomenon can be more reliably prevented.
本願発明の第１２の形態によれば、噴霧ノズルの溶融銀柱に対向する表面であって、流下する溶融銀に向かい合う表面に硬質炭素薄膜を形成し、前記硬質炭素薄膜はダイヤモンド薄膜又はＤＬＣ膜であり、更に前記硬質炭素薄膜の表面に水を流すことにより水膜を形
成するから、前記硬質炭素薄膜への銀の付着とブロッキング現象を防止する銀粉末製造装置を提供できる。
According to the twelfth aspect of the present invention, the hard carbon thin film is formed on the surface of the spray nozzle facing the molten silver column and facing the flowing molten silver, and the hard carbon thin film is a diamond thin film or a DLC film. Furthermore, since a water film is formed by flowing water over the surface of the hard carbon thin film, it is possible to provide a silver powder production apparatus that prevents the adhesion and blocking phenomenon of silver on the hard carbon thin film.
本願発明の第１３の形態によれば、溶融銀の温度を１４００℃以上１６００℃以下とすることで、溶融銀の動粘度を０．２２ｍｍ２／ｓ以下に低下させて溶湯ノズル孔の目詰まりとブロッキング現象を防止し、製造される銀粉末の粒径を小さくする銀粉末製造装置を提供できる。 According to the thirteenth aspect of the present invention, by setting the temperature of the molten silver to 1400 ° C. or more and 1600 ° C. or less, the kinematic viscosity of the molten silver is reduced to 0.22 mm 2 / s or less, and the molten metal nozzle hole is clogged. Thus, a silver powder production apparatus that prevents the blocking phenomenon and reduces the particle size of the produced silver powder can be provided.
本願発明の第１４の形態によれば、溶湯ノズル孔の直径が１ｍｍ以上３ｍｍ以下であり、溶融銀が流下する平均質量流量が０．５ｋｇ／ｍｉｎ以上４．５ｋｇ／ｍｉｎ以下であり、溶湯ノズル孔の直径が小さいほど製造される銀粉末の粒径が小さくなる銀粉末製造装置を提供できる。本形態においては、ブロッキング現象防止のために前記略逆円錐面の頂角を小さく設定したとしても、大きな平均質量流量で溶融銀を流下させて、短時間に多量の銀粉末を製造することができる。 According to the fourteenth aspect of the present invention, the diameter of the melt nozzle hole is 1 mm or more and 3 mm or less, the average mass flow rate at which the molten silver flows down is 0.5 kg / min or more and 4.5 kg / min or less, and the melt nozzle A silver powder production apparatus can be provided in which the particle diameter of the produced silver powder is reduced as the diameter of the hole is reduced. In this embodiment, even if the apex angle of the substantially inverted conical surface is set small in order to prevent the blocking phenomenon, it is possible to produce a large amount of silver powder in a short time by flowing the molten silver at a large average mass flow rate. it can.
本願発明の第１５の形態によれば、熱伝導率が高く、且つ／又は、脆性破壊が起こりにくい素材を溶湯ノズルに用いることにより、溶湯ノズル孔の目詰まりを防止する銀粉末製造装置を提供できる。 According to the fifteenth aspect of the present invention, there is provided a silver powder manufacturing apparatus that prevents clogging of a molten metal nozzle hole by using a material having a high thermal conductivity and / or a material that does not easily cause brittle fracture for a molten metal nozzle. it can.
本願発明の第１６の形態によれば、噴霧する水として脱イオン水を使用することで、不純物が少なく、エレクトロニクス分野の用途に適した銀粉末を製造する銀粉末製造装置を提供できる。尚、求められる銀粉末の純度や、製造コスト面の要請に応じて、脱イオン水の替わりに、蒸留水やＲＯ水等の、純水或いは超純水を使用してもよい。 According to the sixteenth aspect of the present invention, by using deionized water as the water to be sprayed, it is possible to provide a silver powder production apparatus that produces silver powder that has few impurities and is suitable for applications in the electronics field. It should be noted that pure water or ultrapure water such as distilled water or RO water may be used instead of deionized water, depending on the required silver powder purity and manufacturing cost requirements.
以下に、本願発明に係る銀粉末製造方法及び銀粉末製造装置の実施形態を図面に従って詳細に説明する。
図１は本願発明の銀粉末製造装置の１つの実施形態を示す全体概念図であり、図２は本形態における噴霧ノズル３の断面図である。加熱手段２５と温度・BR>ァ御手段２６を備えたタンディッシュ炉２２内には黒鉛るつぼ２１が配置され、黒鉛るつぼ２１内の銀は加熱手段２５により加熱されて溶融銀６となり、黒鉛るつぼ２１に取着された溶湯ノズル２から、溶融銀柱６１の状態で流下する。環状の噴霧ノズル３から第１収束部３４に収束するように略逆円錐面３３に沿って噴霧された水は、略逆円錐面３３の頂部である第１収束部３４において溶融銀６を微粒子化し、銀粒子６２が生成する。第１収束部３４を経た前記水は、略円錐面３５に沿って進行し、軸対称な吸引管５２の内面の第１円環部５３で反射して、第２収束部３７に収束するように第２略逆円錐面３６に沿って進行する。前記水は第２収束部３７において、第１収束部３４で微粒子化されなかった溶融銀６を微粒子化し、及び／又は第１収束部３４で微粒子化された銀粒子６２を更に微粒子化して、銀粒子６２が生成する。吸引管５２が十分に長い場合には、第２収束部３７を経た前記水は、第２略円錐面３８に沿って進行し、軸対称な吸引管５２の内面の第２円環部５４に当たる。
Hereinafter, embodiments of a silver powder production method and a silver powder production apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall conceptual diagram showing one embodiment of the silver powder production apparatus of the present invention, and FIG. 2 is a sectional view of a spray nozzle 3 in this embodiment. A graphite crucible 21 is disposed in a tundish furnace 22 equipped with a heating means 25 and a temperature and control means 26, and the silver in the graphite crucible 21 is heated by the heating means 25 to become molten silver 6, and the graphite crucible. From the molten metal nozzle 2 attached to 21, the molten silver pillar 61 flows down. The water sprayed along the substantially inverted conical surface 33 so as to converge from the annular spray nozzle 3 to the first converging portion 34 causes the molten silver 6 to be finely divided in the first converging portion 34 which is the top of the approximately inverted conical surface 33. As a result, silver particles 62 are generated. The water that has passed through the first converging portion 34 travels along the substantially conical surface 35, is reflected by the first annular portion 53 on the inner surface of the axisymmetric suction pipe 52, and converges on the second converging portion 37. To the second substantially inverted conical surface 36. In the second converging part 37, the water fine particles of the molten silver 6 that has not been atomized by the first converging part 34 and / or further finely atomized silver particles 62 that have been atomized by the first converging part 34, Silver particles 62 are generated. When the suction pipe 52 is sufficiently long, the water that has passed through the second converging portion 37 travels along the second substantially conical surface 38 and hits the second annular portion 54 on the inner surface of the axisymmetric suction pipe 52. .
水槽タンク７１の下部には前記水とともに、生成した銀粒子６１が堆積する。堆積した銀粒子７１は、ポンプ８の吸引送出作用により前記水とともにフィルター手段８１へと輸送される。フィルター手段８１において、前記水と銀粒子６１が分離される。分離された銀粒子６１は、乾燥機８２で乾燥され、銀粉末８３が得られる。 The generated silver particles 61 are deposited in the lower part of the water tank 71 together with the water. The deposited silver particles 71 are transported to the filter means 81 together with the water by the suction and delivery action of the pump 8. In the filter means 81, the water and the silver particles 61 are separated. The separated silver particles 61 are dried with a dryer 82 to obtain a silver powder 83.
高純度の銀粉末を製造するため、噴霧ノズル３から噴霧される前記水は脱イオン水である。銀粉末製造装置１は脱イオン装置９を有し、脱イオン装置９は工業用水入口９１と脱イオン水出口９２を有する。工業用水等の水が脱イオン装置９を通過すると、脱イオン化されて脱イオン水となる。脱イオン水入口９１には工業用水等の水が供給され、脱イオン水出口９２から流出する脱イオン水は、圧力を加えた高圧水として噴霧ノズル３へと導かれる。 In order to produce high-purity silver powder, the water sprayed from the spray nozzle 3 is deionized water. The silver powder production apparatus 1 has a deionization apparatus 9, and the deionization apparatus 9 has an industrial water inlet 91 and a deionized water outlet 92. When water such as industrial water passes through the deionizer 9, it is deionized to become deionized water. Water such as industrial water is supplied to the deionized water inlet 91, and the deionized water flowing out from the deionized water outlet 92 is guided to the spray nozzle 3 as high-pressure water to which pressure is applied.
銀粉末製造蔵置１は、溶融銀柱６１の水平位置を調整する水平位置調整手段２４を備える。水平位置調整手段２４により、前記略逆円錐面３３の頂部である第１収束部３４を溶融銀柱６の内部に設定することができるから、溶融銀柱６１の溶融銀６を第１収束部３４において効率良く粉砕して銀粒子６２を生成し、又、第１収束部３４を経た水の進行経路の軸対称性を確保して、前記水の大部分を前記略円錐面３５に沿って進行させた後、第１円環部５３で反射させ、更に第２略逆円錐面３６に沿って進行させ、第２収束部３７で再び溶融銀柱６１と衝突させることができる。 The silver powder production storage 1 includes a horizontal position adjusting means 24 that adjusts the horizontal position of the molten silver pillar 61. Since the first converging part 34 that is the top of the substantially inverted conical surface 33 can be set inside the molten silver column 6 by the horizontal position adjusting means 24, the molten silver 6 of the molten silver column 61 can be set to the first converging part. The silver particles 62 are efficiently pulverized at 34, and the axial symmetry of the traveling path of the water passing through the first converging portion 34 is ensured, so that most of the water is along the substantially conical surface 35. After traveling, the light can be reflected by the first annular portion 53, further traveled along the second substantially inverted conical surface 36, and collided with the molten silver column 61 again by the second converging portion 37.
図２に示すように、噴霧ノズル３は水が進行する円環状のスリット部（間隙３１）を有する。噴霧ノズル３は上側環状部材４と下側環状部材５を間隙３１を隔てて対向させてなり、水は間隙３１を流路として、水の進行方向を示す矢印３２の向きに、両環状部材の外縁側から内縁側へ向かって進行する。上側環状部材４の下面は湾曲した上側円環面４１を含み、下側環状部材５の上面は湾曲した下側円環面５１を含み、互いに対向する上側円環面４１と下側円環面５１の間隔は内縁側ほど狭くなっている。上側環状部材４の下面の最内縁部は、上側円環面４１の上縁部と段差なく接続する円環状反射面４２である。間隙３１内を外縁側から内縁側へ向かって進行した前記水を、円環状反射面４２に当てて下方に向けて反射することで、前記水は略逆円錐面３３に沿って第１収束部３４に収束するように全周途切れなく、全周ほぼ均一に噴霧される。 As shown in FIG. 2, the spray nozzle 3 has an annular slit (gap 31) through which water travels. The spray nozzle 3 has the upper annular member 4 and the lower annular member 5 opposed to each other with a gap 31 therebetween, and the water passes through the gap 31 in the direction of an arrow 32 indicating the direction of water travel. Proceed from the outer edge side toward the inner edge side. The lower surface of the upper annular member 4 includes a curved upper annular surface 41, and the upper surface of the lower annular member 5 includes a curved lower annular surface 51, and the upper annular surface 41 and the lower annular surface facing each other. The interval 51 is narrower toward the inner edge side. The innermost edge portion of the lower surface of the upper annular member 4 is an annular reflecting surface 42 that is connected to the upper edge portion of the upper annular surface 41 without a step. The water that has traveled from the outer edge side to the inner edge side in the gap 31 is applied to the annular reflecting surface 42 and reflected downward, so that the water is reflected along the substantially inverted conical surface 33 to the first converging portion. The spray is sprayed almost uniformly over the entire circumference without interruption.
下側環状部材５はその下部に軸対称な吸引管５２を備え、吸引管５２の内面は、吸引管５２を除く下側環状部材５の内面と段差なく滑らかに接続している。したがって、当該接続部分の近傍における吸い込み気流の乱れの発生を抑制することができる。
吸引管５２の内面の形状は直円筒形に限られない。当該内面は一般に、滑らかな曲線を軸の周りに回転して得られる回転面の形状を有する。
The lower annular member 5 includes an axisymmetric suction pipe 52 at the lower portion thereof, and the inner surface of the suction pipe 52 is smoothly connected to the inner surface of the lower annular member 5 excluding the suction pipe 52 without a step. Therefore, it is possible to suppress the turbulence of the suction airflow in the vicinity of the connection portion.
The shape of the inner surface of the suction pipe 52 is not limited to a right cylindrical shape. The inner surface generally has the shape of a rotating surface obtained by rotating a smooth curve around an axis.
１つの実施形態においては、吸引管５２の形状は、第１収束部３４を経た水が反射する前記第１円環部５３が、吸引管５２の内面に存在するように選択される。この形状の選択により、第１収束部３４だけでなく、第２収束部３７においても溶融銀６及び／又は銀粒子６２を再び微粒子化することが可能となるから、短時間に多量の銀粒子を効率良く生成することができる。 In one embodiment, the shape of the suction tube 52 is selected such that the first annular portion 53 that reflects the water that has passed through the first converging portion 34 is present on the inner surface of the suction tube 52. By selecting the shape, not only the first converging part 34 but also the second converging part 37 can make the molten silver 6 and / or silver particles 62 finer again, so that a large amount of silver particles can be obtained in a short time. Can be generated efficiently.
当該実施形態において、特に吸引管５２の内面の形状が直円筒の場合には、吸引管５２の内直径をＤとし、吸引管５２の長さ（より正確には円環状反射面４２から吸引管５２の下端までの距離）をＬとし、略逆円錐面３３の頂角の大きさをθとして、次の（式１）の関係が成立する。
（式１） Ｌ・ｔａｎ(θ/２) ＞ Ｄ
ただし、重力による影響を無視して、略逆円錐面３３の頂角、略円錐面３５の頂角、第２略逆円錐面３６の頂角、及び第２略円錐面の頂角は、すべて大きさが等しくθであるとみなす近似を行った。
ブロッキング現象の防止のためには、後述するように、頂角θは２５°以上３０°以下に設定することが好ましい。この場合、関係 Ｌ／Ｄ ≧ ５ が満足されていれば、（式１）の条件を満たすことができる。
In this embodiment, particularly when the shape of the inner surface of the suction tube 52 is a right cylinder, the inner diameter of the suction tube 52 is D, and the length of the suction tube 52 (more precisely, the suction tube from the annular reflecting surface 42). When the distance to the lower end of 52 is L and the magnitude of the apex angle of the substantially inverted conical surface 33 is θ, the following relationship (Equation 1) is established.
(Expression 1) L · tan (θ / 2)> D
However, ignoring the influence of gravity, the apex angle of the substantially inverted conical surface 33, the apex angle of the approximately conical surface 35, the apex angle of the second approximately inverted conical surface 36, and the apex angle of the second approximately conical surface are all An approximation was performed assuming that the magnitudes were equal and θ.
In order to prevent the blocking phenomenon, the apex angle θ is preferably set to 25 ° or more and 30 ° or less as described later. In this case, if the relationship L / D ≧ 5 is satisfied, the condition of (Expression 1) can be satisfied.
別の実施形態においては、吸引管５２の形状は、第２収束部３７が吸引管５２の最下端部より上方に位置するように選択される。この形状選択により、吸い込み気流の乱れを抑制し、ブロッキング現象の発生を防止することができる。 In another embodiment, the shape of the suction tube 52 is selected such that the second converging portion 37 is located above the lowermost end of the suction tube 52. By this shape selection, it is possible to suppress the disturbance of the suction airflow and prevent the occurrence of the blocking phenomenon.
当該実施形態において、特に吸引管５２の内面の形状が直円筒の場合には、上記の近似のもとで、形状パラメータＤ、Ｌ、θの間には次の（式２）の関係が成立する。
（式２） Ｌ・ｔａｎ(θ/２) ＞ (３／２)・Ｄ
頂角θを２５°以上３０°以下に設定する場合、関係 Ｌ／Ｄ ≧ ７ が満足されていれば、（式２）の条件を満たすことができる。
In the present embodiment, particularly when the shape of the inner surface of the suction tube 52 is a right cylinder, the following relationship (Formula 2) is established among the shape parameters D, L, and θ under the above approximation. To do.
(Expression 2) L · tan (θ / 2)> (3/2) · D
When the apex angle θ is set to 25 ° or more and 30 ° or less, the condition of (Equation 2) can be satisfied as long as the relationship L / D ≧ 7 is satisfied.
更に別の実施形態においては、吸引管５２の形状は、第２収束部３７を経た水が反射する前記第２円環部５４が、吸引管５２の内面に存在するように選択される。この形状選択により、吸い込み気流の乱れを抑制し、ブロッキング現象の発生をより確実に防止することができる。 In yet another embodiment, the shape of the suction tube 52 is selected such that the second annular portion 54 that reflects the water that has passed through the second converging portion 37 is present on the inner surface of the suction tube 52. By this shape selection, the disturbance of the suction airflow can be suppressed and the occurrence of the blocking phenomenon can be prevented more reliably.
当該実施形態において、特に吸引管５２の内面の形状が直円筒の場合には、上記の近似のもとで、形状パラメータＤ、Ｌ、θの間には次の（式３）の関係が成立する。
（式３） Ｌ・ｔａｎ(θ/２) ＞ ２Ｄ
頂角θを２５°以上３０°以下に設定する場合、関係 Ｌ／Ｄ ＞ ９ が満足されていれば、（式３）の条件を満たすことができる。
In the embodiment, particularly when the shape of the inner surface of the suction tube 52 is a right cylinder, the following relationship (Formula 3) is established between the shape parameters D, L, and θ under the above approximation. To do.
(Expression 3) L · tan (θ / 2)> 2D
When the apex angle θ is set to 25 ° or more and 30 ° or less, the condition of (Expression 3) can be satisfied as long as the relationship L / D> 9 is satisfied.
流下する溶融銀６の平均質量流量が２ｋｇ／分である溶融銀柱６１に、２５°以上３０°以下の頂角θで噴霧ノズル３から２００Ｌ／ｍｉｎ以上の体積流量で水を噴霧すれば、溶融銀６を第１収束部と第２収束部の２箇所において効率よく微粒子化することができる。この場合、吸い込み気流の乱れを抑制し、ブロッキング現象の発生を確実に防止するためには、直円筒形状の吸引管の場合、吸引管５２の径及び長さを関係 Ｌ／Ｄ ≧ ７ を
満たすように設定することが好ましい。
If water is sprayed at a volume flow rate of 200 L / min or more from the spray nozzle 3 at an apex angle θ of 25 ° or more and 30 ° or less onto the molten silver column 61 whose average mass flow rate of the molten silver 6 flowing down is 2 kg / min, The molten silver 6 can be efficiently atomized at two locations, the first converging portion and the second converging portion. In this case, in order to suppress the disturbance of the suction air flow and to surely prevent the occurrence of the blocking phenomenon, the diameter and length of the suction tube 52 satisfy the relationship L / D ≧ 7 in the case of a straight cylindrical suction tube. It is preferable to set so.
噴霧ノズル３から噴霧される水が形成する角度θ、即ち略逆円錐面３３の頂角θを３０°以下とすることで、噴霧される水が引き起こす吸い込み気流による吸引力が強くなり、噴霧ノズル３への銀粒子６２及び溶融銀６の飛沫の付着・堆積を抑制することができ、且つ、製造される銀粉末８３の粒度が小さくなる。 By setting the angle θ formed by the water sprayed from the spray nozzle 3, that is, the apex angle θ of the substantially inverted conical surface 33 to 30 ° or less, the suction force by the suction air flow caused by the sprayed water becomes strong, and the spray nozzle 3 can be prevented from adhering / depositing the droplets of the silver particles 62 and the molten silver 6, and the particle size of the silver powder 83 to be produced is reduced.
一方、前記角度θを小さく設定しすぎると、銀粉末８３の製造効率が低下する。そこで、前記角度θは通常２５°以上３０°以下の範囲とする。しかし、好ましい角度θの範囲は、噴霧ノズル３の直径、噴霧圧力、噴霧される水の体積流量等に応じて変わるので、必ずしも上記の範囲に限定されるものではない。 On the other hand, if the angle θ is set too small, the production efficiency of the silver powder 83 decreases. Therefore, the angle θ is usually in the range of 25 ° to 30 °. However, the preferable range of the angle θ varies depending on the diameter of the spray nozzle 3, the spray pressure, the volume flow rate of the sprayed water, and the like, and is not necessarily limited to the above range.
図３は、本願発明の１つの実施形態において、上側環状部材４３の上面の溶融銀柱６１に対向する表面に硬質炭素薄膜４３を形成し、更に硬質炭素薄膜４３の上に水を流して、流水による水膜４４を形成した噴霧ノズル３の断面図である。噴霧ノズル３から略逆円錐面３３に沿って噴霧された水は、第１収束部３４において溶融銀柱６１の溶融銀６を微粒子化し、銀粒子６２が生成する。硬質炭素薄膜４３及び流水による水膜４４は、銀粒子６２や溶融銀６の飛沫が噴霧ノズル３の上面の溶融銀柱６１に対向する表面に付着・堆積してブロッキング現象を引き起こすことを防止する。したがって、本実施形態においては安定的に銀粉末８３を製造することができる。 3, in one embodiment of the present invention, the hard carbon thin film 43 is formed on the surface of the upper surface of the upper annular member 43 facing the molten silver column 61, and water is further flowed over the hard carbon thin film 43. It is sectional drawing of the spray nozzle 3 in which the water film 44 by flowing water was formed. The water sprayed from the spray nozzle 3 along the substantially inverted conical surface 33 finely forms the molten silver 6 of the molten silver column 61 in the first converging part 34, thereby generating silver particles 62. The hard carbon thin film 43 and the water film 44 by running water prevent the silver particles 62 and the splash of the molten silver 6 from adhering to and depositing on the surface of the upper surface of the spray nozzle 3 facing the molten silver column 61 to cause a blocking phenomenon. . Therefore, in this embodiment, the silver powder 83 can be manufactured stably.
硬質炭素薄膜４３はダイヤモンド薄膜又はＤＬＣ膜であり、いずれも銀と化学的に反応しない素材である。流水による水膜４４の形成は、噴霧ノズル３への銀の付着・堆積を防ぐために行われる操作であるが、硬質炭素薄膜４３を形成することでその効果が一層有効になる。硬質炭素薄膜４３は、噴霧ノズル３の表面にＣＶＤ、ＰＶＤ、メッキ、スパッタリングなどの手法を用いて形成される。 The hard carbon thin film 43 is a diamond thin film or a DLC film, and both are materials that do not chemically react with silver. The formation of the water film 44 by flowing water is an operation performed to prevent the adhesion / deposition of silver to the spray nozzle 3, but the effect becomes more effective by forming the hard carbon thin film 43. The hard carbon thin film 43 is formed on the surface of the spray nozzle 3 using a technique such as CVD, PVD, plating, or sputtering.
硬質炭素薄膜４３の厚さ、及び流水による水膜４４の厚さは、ブロッキング現象を防ぐことができる限りにおいて、限定されるものではない。ブロッキング現象を防止する上で好ましい硬質炭素薄膜４３の厚さ、及び、好ましい流水による水膜４４の厚さは、噴霧ノズル３から噴霧される水の体積流量、流下する溶融銀６の平均質量流量、略逆円錐面３３の頂角θ、吸引管５２の形状（径及び長さ）等に依存し、特に、噴霧ノズル３から噴霧される水の体積流量に依存する。 The thickness of the hard carbon thin film 43 and the thickness of the water film 44 by running water are not limited as long as the blocking phenomenon can be prevented. The thickness of the hard carbon thin film 43 preferable for preventing the blocking phenomenon and the preferable thickness of the water film 44 by flowing water are the volume flow rate of water sprayed from the spray nozzle 3 and the average mass flow rate of the molten silver 6 flowing down. , Which depends on the apex angle θ of the substantially inverted conical surface 33, the shape (diameter and length) of the suction tube 52, and in particular, depends on the volume flow rate of water sprayed from the spray nozzle 3.
図４は、本願発明の１つの実施形態における黒鉛るつぼ２１と、それに取着した溶湯ノズル２、及び、溶湯ノズル２を貫通する溶湯ノズル孔２３を示す。黒鉛るつぼ２１内の溶融銀６は、溶湯ノズル２の溶湯ノズル孔２３を通って、溶融銀柱６１の状態で流下する。 FIG. 4 shows a graphite crucible 21, a melt nozzle 2 attached thereto, and a melt nozzle hole 23 penetrating the melt nozzle 2 in one embodiment of the present invention. The molten silver 6 in the graphite crucible 21 flows down in the state of the molten silver column 61 through the molten metal nozzle hole 23 of the molten metal nozzle 2.
アトマイズ法で金属を溶融する際には従来、加熱手段２４を備えたタンディッシュ炉２２として高周波誘導加熱炉が用いられ、そこでは黒鉛るつぼと黒鉛製ノズルが利用されてきた。黒鉛の熱伝導率は８０Ｗ／(ｍ・Ｋ)から１４０Ｗ／(ｍ・Ｋ)と非常に高いが、黒鉛には脆いという欠点がある。アトマイズ法で溶湯ノズル孔２３の目詰まりを防ぐには溶湯ノズル孔２３の直径を大きくするとよい。しかし、製造される銀粉末の粒度を細かくする観点からは逆に、溶湯ノズル孔２３の直径を小さくする必要がある。溶湯ノズル２として黒鉛製ノズルを用いた場合、溶湯ノズル孔２３の直径を小さくしすぎると、脆いためアトマイズ中に溶湯ノズル孔２３の先端で銀の溶湯（溶融銀６）が目詰まりしてアトマイズが中断する問題がある。 When melting metal by the atomizing method, a high-frequency induction heating furnace has been conventionally used as the tundish furnace 22 provided with the heating means 24, and a graphite crucible and a graphite nozzle have been used there. The thermal conductivity of graphite is as high as 80 W / (m · K) to 140 W / (m · K), but graphite has a drawback of being brittle. In order to prevent clogging of the molten metal nozzle hole 23 by the atomizing method, the diameter of the molten metal nozzle hole 23 may be increased. However, conversely, from the viewpoint of reducing the particle size of the silver powder to be produced, it is necessary to reduce the diameter of the molten metal nozzle hole 23. When a graphite nozzle is used as the molten metal nozzle 2, if the diameter of the molten metal nozzle hole 23 is made too small, the molten metal is clogged at the tip of the molten metal nozzle hole 23 during atomization, and the atomized metal is melted. There is a problem that interrupts.
本願発明の１つの実施形態においては、溶湯ノズル２の材質を窒化アルミニウム、窒化ケイ素、窒化ホウ素、炭化ケイ素、酸化マグネシウム、酸化アルミニウムのいずれかとし
、より好ましくは窒化アルミニウム又は窒化ケイ素とし、更に好ましくは窒化ケイ素にすることで、溶湯ノズル孔２３での銀の目詰まりを防ぎ、安定した銀粉末を製造することができる。熱伝導率が高い窒化アルミニウム及び窒化ケイ素は溶湯ノズル２の素材として適しており、その中でも脆性破壊が起こらない窒化ケイ素は、溶湯ノズル２の素材として特に適している。
溶湯ノズル孔２３の直径は１ｍｍから３ｍｍの範囲とする。当該直径が小さいほど製造される銀粉末８３の粒度が小さくなる。
In one embodiment of the present invention, the material of the molten metal nozzle 2 is any one of aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, and aluminum oxide, more preferably aluminum nitride or silicon nitride, and still more preferably By using silicon nitride, clogging of silver in the molten metal nozzle hole 23 can be prevented, and a stable silver powder can be produced. Aluminum nitride and silicon nitride having high thermal conductivity are suitable as the material for the molten metal nozzle 2, and among these, silicon nitride that does not cause brittle fracture is particularly suitable as the material for the molten metal nozzle 2.
The diameter of the molten metal nozzle hole 23 is in the range of 1 mm to 3 mm. The smaller the diameter, the smaller the particle size of the silver powder 83 produced.
本願発明の１つの実施形態においては、噴霧ノズル３から噴霧する水を脱イオン水とすることで、高純度の銀粉末８３を製造することができる。当該実施形態において更に、噴霧ノズル３の表面に硬質炭素薄膜４３と流水による水膜４４を形成する場合には、銀粉末８３の純度を高くする観点から、流水による水膜４４は脱イオン水を流すことにより形成することが好ましい。 In one embodiment of the present invention, high-purity silver powder 83 can be produced by using deionized water as the water sprayed from the spray nozzle 3. In this embodiment, when forming the hard carbon thin film 43 and the water film 44 by running water on the surface of the spray nozzle 3, the water film 44 by running water uses deionized water from the viewpoint of increasing the purity of the silver powder 83. It is preferable to form by flowing.
以下、実施例により本願発明を説明する。
＜実施例１＞ 銀の塊状物４０ｋｇを高周波溶解炉２２内の黒鉛るつぼ２１に充填し、窒素雰囲気中１３７０℃まで昇温して溶解した。溶解後、窒化ケイ素の溶湯ノズル２から銀の溶湯を流下させながら、ダイヤモンド薄膜４３と流水による水膜４４を備えた円環状の噴霧ノズル３を用いて水を噴霧した。水の噴霧圧力は８０ＭＰａ、体積流量は２２０Ｌ／ｍｉｎとした。前記水及び流水は脱イオン水を用いた。溶湯ノズル孔２３の直径は１．８ｍｍ、流下する溶融銀６の平均質量流量は２ｋｇ／ｍｉｎ、吸引管５２は直円筒形状で、その内直径Ｄは３ｃｍ、長さＬは２５ｃｍであった。噴霧ノズル３からの水の噴霧により銀は粉砕されて、銀粒子６２が生成し、水槽タンク７で貯留した後、フィルタープレス８１で濾過し、乾燥機８２において６０℃で乾燥し、銀粉末８３を得た。
The present invention will be described below with reference to examples.
<Example 1> 40 kg of silver lump was filled in a graphite crucible 21 in a high-frequency melting furnace 22 and heated to 1370 ° C in a nitrogen atmosphere to be melted. After melting, water was sprayed using an annular spray nozzle 3 provided with a diamond thin film 43 and a water film 44 by flowing water while flowing a molten silver from the melt nozzle 2 of silicon nitride. The water spray pressure was 80 MPa, and the volume flow rate was 220 L / min. Deionized water was used as the water and running water. The diameter of the molten metal nozzle hole 23 was 1.8 mm, the average mass flow rate of the molten silver 6 flowing down was 2 kg / min, the suction tube 52 was a straight cylinder, its inner diameter D was 3 cm, and the length L was 25 cm. Silver is pulverized by spraying water from the spray nozzle 3 to produce silver particles 62, stored in the water tank 7, filtered through a filter press 81, dried at 60 ° C. in a dryer 82, and silver powder 83. Got.
図５は、実施例１で得られた銀粉末８３のＳＥＭ画像（JEOL JSM-6510）であり、図６は、同じく粒度分布（日機装 MT3300EXII）を示す。ＳＥＭ画像から、銀粉末８３には球状、楕円状、破砕状等の形状の粒子が含まれている。粒度分布から、体積基準の平均粒径は８．２μｍ、個数基準の平均粒径は２．５μｍであった。 FIG. 5 is an SEM image (JEOL JSM-6510) of the silver powder 83 obtained in Example 1, and FIG. 6 also shows the particle size distribution (Nikkiso MT3300EXII). From the SEM image, the silver powder 83 includes particles having a spherical shape, an elliptical shape, a crushed shape, or the like. From the particle size distribution, the volume-based average particle size was 8.2 μm, and the number-based average particle size was 2.5 μm.
図７は、実施例１で得られた銀粉末８３の粉末Ｘ線回折図（Shimazu XRD-6100）である。Ｘ線源にはＣｕＫα線を用い、印加電圧および印加電流はそれぞれ４０ｋＶおよび３０ｍＡとして、２θが３０°〜９０°の範囲を０．０２°のステップ幅で測定した。銀へ結晶化しており、銀の粉末Ｘ線回折データ（JCPDS 04-0783）と一致している。デバイ・シェーラーの式（式４）から求められる結晶子の大きさは１８．４ｎｍであった。
（式４） τ ＝ Ｋλ／（βｃｏｓθ）
ここで、Ｋは形状因子、λはＸ線波長、βはピーク半値全幅、θはブラッグ角、τは結晶子の大きさである。
FIG. 7 is a powder X-ray diffraction pattern (Shimazu XRD-6100) of the silver powder 83 obtained in Example 1. CuKα rays were used as the X-ray source, the applied voltage and the applied current were 40 kV and 30 mA, respectively, and the range of 2θ between 30 ° and 90 ° was measured with a step width of 0.02 °. It is crystallized into silver and is consistent with the powder X-ray diffraction data (JCPDS 04-0783) of silver. The crystallite size obtained from the Debye-Scherrer equation (Equation 4) was 18.4 nm.
(Formula 4) τ = Kλ / (βcosθ)
Here, K is the shape factor, λ is the X-ray wavelength, β is the full width at half maximum of the peak, θ is the Bragg angle, and τ is the size of the crystallite.
図８は、実施例１で得られた銀粉末８３を原料とする銀ペーストの、熱機械分析（リガク TMA8310）による収縮曲線である。銀粉末８３を、エチルセルロースをブチルカルビトールアセテートに溶かしたビヒクルと混合して銀ペーストを調製した。銀粉末８３、エチルセルロースおよびブチルカルビトールアセテートの混合比は重量比で８５ｗｔ％：２ｗｔ％：１３ｗｔ％とした。このときの銀ペーストの粘度は約２００Ｐａ・ｓとした。銀ペーストをＰＥＴフィルム上にドクターブレードで約２５０μｍの膜厚で塗工した後、１００℃で２時間乾燥した。ＰＥＴフィルムから膜を剥がし、１３ｍｍφの円盤型にくり抜いて試料を加熱し、５℃／ｍｉｎの昇温速度で９００℃まで昇温した。（ａ）と（ｂ）は本願発明に関わる結果であり、（ｂ）に係る銀粉末は、分級機を用いて（ａ）の銀粉末８３の粒度を２．５μｍ以下にし、（ｃ）の粒度とほぼ同じにしたものである。（ｃ）は湿式
還元法で製造した銀粉末の結果である。（ｃ）に比べて（ａ）の収縮率が小さいのは（ａ）の銀粉末には粗大な粒子が含まれているためである。
FIG. 8 is a shrinkage curve of the silver paste using the silver powder 83 obtained in Example 1 as a raw material by thermomechanical analysis (Rigaku TMA8310). Silver powder 83 was mixed with a vehicle in which ethyl cellulose was dissolved in butyl carbitol acetate to prepare a silver paste. The mixing ratio of silver powder 83, ethyl cellulose and butyl carbitol acetate was 85 wt%: 2 wt%: 13 wt% in weight ratio. The viscosity of the silver paste at this time was about 200 Pa · s. The silver paste was coated on a PET film with a doctor blade with a film thickness of about 250 μm, and then dried at 100 ° C. for 2 hours. The film was peeled off from the PET film, cut into a disk shape of 13 mmφ, and the sample was heated, and the temperature was raised to 900 ° C. at a rate of 5 ° C./min. (A) and (b) are the results relating to the present invention, and the silver powder according to (b) uses a classifier to reduce the particle size of the silver powder 83 of (a) to 2.5 μm or less, and (c) The grain size is almost the same. (C) is a result of the silver powder manufactured by the wet reduction method. The reason why the shrinkage rate of (a) is smaller than that of (c) is that the silver powder of (a) contains coarse particles.
表１は、実施例１で得られた銀粉末８３に含まれる不純物含有量を２つの比較試料と対照して示す。銀粉末８３は希硝酸により溶解後、１００ｐｐｍに希釈してＩＣＰ発光分光分析装置（Horiba ULTIMA2）により測定した。比較試料１は、私水（工業用水）をそのまま用いて水アトマイズして製造した銀粉末である。比較試料２は湿式還元法で製造した銀粉末である。実施例１の銀粉末８３は、比較試料１及び比較試料２に比べて不純物が少なく、エレクトロニクス分野の用途に適している。 Table 1 shows the impurity content contained in the silver powder 83 obtained in Example 1 in contrast to two comparative samples. The silver powder 83 was dissolved in dilute nitric acid, diluted to 100 ppm, and measured with an ICP emission spectroscopic analyzer (Horiba ULTIMA2). Comparative sample 1 is a silver powder produced by water atomization using private water (industrial water) as it is. Comparative sample 2 is a silver powder produced by a wet reduction method. The silver powder 83 of Example 1 has fewer impurities than the comparative sample 1 and the comparative sample 2, and is suitable for applications in the electronics field.
図8は、実施例１で得られた銀粉末８３を原料として用いた銀ペーストの焼結後の電気抵抗率が、焼結温度によってどう変わるかを、２つの比較試料と対照して示す。銀粉末８３を、エチルセルロースをブチルカルビトールアセテートに溶かしたビヒクルと混合して銀ペーストを調製した。銀粉末８３、エチルセルロースおよびブチルカルビトールアセテートの混合比は重量比で８５ｗｔ％：２ｗｔ％：１３ｗｔ％とした。このときの銀ペーストの粘度は約２００Ｐａ・ｓとした。銀ペーストをＰＥＴフィルム上にドクターブレードで約２５０μｍの膜厚で塗工した後、１００℃で２時間乾燥した。ＰＥＴフィルムから膜を剥がし、１３ｍｍφの円盤型にくり抜いて５つのサンプルを準備した。各々のサンプルを加熱し、５℃／ｍｉｎの昇温速度でそれぞれ５００℃、６００℃、７００℃、８００℃、又は９００℃まで昇温した。室温まで冷却した後、各サンプルに白金電極を取り付けてマルチメーター（三菱化学 MCP-T360）で比抵抗を測定した。 FIG. 8 shows how the electrical resistivity after sintering of the silver paste using the silver powder 83 obtained in Example 1 as a raw material varies depending on the sintering temperature, in contrast to two comparative samples. Silver powder 83 was mixed with a vehicle in which ethyl cellulose was dissolved in butyl carbitol acetate to prepare a silver paste. The mixing ratio of silver powder 83, ethyl cellulose and butyl carbitol acetate was 85 wt%: 2 wt%: 13 wt% in weight ratio. The viscosity of the silver paste at this time was about 200 Pa · s. The silver paste was coated on a PET film with a doctor blade with a film thickness of about 250 μm, and then dried at 100 ° C. for 2 hours. The film was peeled off from the PET film and cut into a 13 mmφ disk shape to prepare five samples. Each sample was heated and heated to 500 ° C., 600 ° C., 700 ° C., 800 ° C., or 900 ° C. at a temperature rising rate of 5 ° C./min, respectively. After cooling to room temperature, a platinum electrode was attached to each sample, and the specific resistance was measured with a multimeter (Mitsubishi Chemical MCP-T360).
丸印は本願発明の実施例１に関わる結果、三角印は私水（工業用水）でアトマイズした銀粉末の結果、四角印は湿式還元法で製造した銀粉末の結果である。本願発明の銀粉末８３は不純物含有量が少ないため、いずれの焼結温度においても焼結後のサンプルが最も小さい電気抵抗率を示し、エレクトロニクス分野の用途に適している。 Circles indicate the results of Example 1 of the present invention, triangles indicate the results of silver powder atomized with private water (industrial water), and squares indicate the results of silver powder produced by the wet reduction method. Since the silver powder 83 of the present invention has a low impurity content, the sintered sample exhibits the lowest electrical resistivity at any sintering temperature, and is suitable for applications in the electronics field.
＜実施例２＞ 表２は溶湯ノズル２の材質による銀の目詰まりの発生の有無を示す。溶湯ノズル２の素材には黒鉛、アルミナ、窒化ケイ素を用いた。１３７０℃で２５ｋｇの銀を溶解し、圧力８０ＭＰａ、体積流量２２０Ｌ／ｍｉｎの水を噴霧して水アトマイズした。流下する溶融銀６の平均質量流量は２ｋｇ／ｍｉｎ、溶湯ノズル孔２３の直径は１．８ｍ
ｍであった。
Example 2 Table 2 shows whether silver clogging occurs due to the material of the molten metal nozzle 2. Graphite, alumina, and silicon nitride were used for the material of the molten metal nozzle 2. 25 kg of silver was dissolved at 1370 ° C., and water atomization was performed by spraying water with a pressure of 80 MPa and a volume flow rate of 220 L / min. The average mass flow rate of the molten silver 6 flowing down is 2 kg / min, and the diameter of the molten metal nozzle hole 23 is 1.8 m.
m.
溶湯ノズル２の材質が黒鉛やアルミナの場合には、２５ｋｇの銀のアトマイズ中に黒鉛るつぼ２１の不純物がノズルに堆積して溶湯ノズル孔２３の目詰まりを起こす。一方、窒化ケイ素の場合には、４０ｋｇの銀をアトマイズしても目詰まりが起きない。窒化ケイ素は高温での靱性、耐熱衝撃性に最も優れ、熱膨張係数も小さいので、窒化ケイ素からなる溶湯ノズル２は、アトマイズ中の温度変化に対して最も信頼性が高い。 When the material of the molten metal nozzle 2 is graphite or alumina, impurities in the graphite crucible 21 are deposited on the nozzle during 25 kg of silver atomization, and the molten metal nozzle hole 23 is clogged. On the other hand, in the case of silicon nitride, clogging does not occur even when 40 kg of silver is atomized. Since silicon nitride is most excellent in toughness and thermal shock resistance at high temperatures and has a small thermal expansion coefficient, the molten metal nozzle 2 made of silicon nitride has the highest reliability against temperature changes during atomization.
＜実施例３＞ 表３は、噴霧ノズル３におけるブロッキング現象の発生の有無が、噴霧される水の角度(頂角θ)によってどう変わるかを示す。溶湯ノズル２にはアルミナを用いた。１３７０℃で２５ｋｇの銀を溶解し、平均質量流量２ｋｇ／ｍｉｎで溶融銀を流下させ、圧力８０ＭＰａ、体積流量２２０Ｌ／ｍｉｎの水を噴霧してアトマイズした。内直径Ｄが３ｃｍ、長さＬが２５ｃｍの直円筒形状の吸引管５２を用いた。頂角θを小さくすることで、溶融銀の飛沫が上方に向かって飛散しにくくなり、又、吸い込み気流による吸引力のため、噴霧ノズル３への銀の付着が起こりにくくなる。また、頂角θを小さくすると、銀の溶湯の粉砕が促進されて、製造される銀粉末の粒度がやや小さくなる。 <Example 3> Table 3 shows how the presence or absence of the blocking phenomenon in the spray nozzle 3 varies depending on the angle of the sprayed water (vertical angle θ). Alumina was used for the molten metal nozzle 2. 25 kg of silver was dissolved at 1370 ° C., molten silver was allowed to flow down at an average mass flow rate of 2 kg / min, and atomized by spraying water with a pressure of 80 MPa and a volume flow rate of 220 L / min. A straight cylindrical suction tube 52 having an inner diameter D of 3 cm and a length L of 25 cm was used. By making the apex angle θ small, it becomes difficult for splashes of molten silver to scatter upward, and it becomes difficult for silver to adhere to the spray nozzle 3 due to the suction force caused by the suction airflow. Further, when the apex angle θ is reduced, the pulverization of the molten silver is promoted, and the particle size of the produced silver powder is slightly reduced.
＜実施例４＞ 表４は、噴霧ノズル３におけるブロッキング現象の発生の有無が、吸引管５２の形状（長さの比Ｌ／Ｄ）によってどう変わるかを示す。溶湯ノズル２にはアルミナを用い、溶湯ノズル孔の直径は１．８ｍｍであった。１３７０℃で２５ｋｇの銀を溶解し、平均質量流量２ｋｇ／ｍｉｎで溶融銀を流下させ、圧力８０ＭＰａ、体積流量２２０Ｌ／ｍｉｎの水を噴霧してアトマイズした。頂角θは２５°、直円筒形状の吸引管５２の内直径Ｄは３ｃｍとした。長さの比Ｌ／Ｄが大きいほど、吸い込み気流の乱れが少なくなるため、ブロッキング現象は発生しにくくなる。 Example 4 Table 4 shows how the presence or absence of the blocking phenomenon in the spray nozzle 3 changes depending on the shape of the suction pipe 52 (length ratio L / D). Alumina was used for the molten metal nozzle 2 and the diameter of the molten metal nozzle hole was 1.8 mm. 25 kg of silver was dissolved at 1370 ° C., molten silver was allowed to flow down at an average mass flow rate of 2 kg / min, and atomized by spraying water with a pressure of 80 MPa and a volume flow rate of 220 L / min. The apex angle θ was 25 °, and the inner diameter D of the straight cylindrical suction tube 52 was 3 cm. As the length ratio L / D increases, the disturbance of the suction airflow decreases, and thus the blocking phenomenon is less likely to occur.
本願発明に係る水アトマイズ法で製造した銀粉末は、高純度で且つ結晶化が進行しており、導電性ペーストの原料として使用した場合には、低い焼結温度で高い電気電導度を示す。太陽電池向け電極ペースト、導電性ペースト、インダクターに使えば省エネ機器やモバイル機器の信頼性向上に繋がる。又、製造効率が高く、且つ長時間の安定生産が可能な製造方法であるため、製造コストを低下させることができる。本願発明の銀粉末製造方法及び新粉末製造装置は、エレクトロニクス分野に関係する多くの業界において広く利用できるものである。 The silver powder produced by the water atomization method according to the present invention has high purity and crystallization, and when used as a raw material for the conductive paste, exhibits high electrical conductivity at a low sintering temperature. Use in solar cell electrode pastes, conductive pastes, and inductors will help improve the reliability of energy-saving and mobile devices. In addition, since the manufacturing method is high and stable production for a long time is possible, the manufacturing cost can be reduced. The silver powder production method and the new powder production apparatus of the present invention can be widely used in many industries related to the electronics field.
１ 銀粉末製造装置
２ 溶湯ノズル
３ 噴霧ノズル
４ 上側環状部材
５ 下側環状部材
６ 溶融銀
７ 水槽タンク
８ ポンプ
９ 脱イオン装置
２１ 黒鉛るつぼ
２２ タンディッシュ炉
２３ 溶湯ノズル孔
２４ 水平位置調整手段
２５ 加熱手段
２６ 温度制御手段
３１ 間隙
３２ 水の進行方向を示す矢印
３３ 略逆円錐面
３４ 第１収束部
３５ 略円錐面
３６ 第２略逆円錐面
３７ 第２収束部
３８ 第２略円錐面
４１ 上側円環面
４２ 円環状反射面
４３ 硬質炭素薄膜
４４ 流水による水膜
５１ 下側円環面
５２ 吸引管
５３ 第１円環部
５４ 第２円環部
６１ 溶融銀柱
７１ 堆積した銀粒子
８１ フィルター手段
８２ 乾燥機
８３ 銀粉末
９１ 工業用水入口
９２ 脱イオン水出口
DESCRIPTION OF SYMBOLS 1 Silver powder manufacturing apparatus 2 Molten metal nozzle 3 Spray nozzle 4 Upper annular member 5 Lower annular member 6 Molten silver 7 Water tank 8 Pump 9 Deionizer 21 Graphite crucible 22 Tundish furnace 23 Molten nozzle hole 24 Horizontal position adjustment means 25 Heating Means 26 Temperature control means 31 Gap 32 Arrow indicating the traveling direction of water 33 Substantially conical surface 34 First converging portion 35 Substantially conical surface 36 Second substantially conical surface 37 Second converging portion 38 Second substantially conical surface 41 Upper circle Annular surface 42 Annular reflecting surface 43 Hard carbon thin film 44 Water film by flowing water 51 Lower annular surface 52 Suction tube 53 First annular part 54 Second annular part 61 Molten silver column 71 Deposited silver particles 81 Filter means 82 Dryer 83 Silver powder 91 Industrial water inlet 92 Deionized water outlet
Claims (16)
前記溶融銀の温度を１４００℃以上１６００℃以下とすることで、前記溶融銀の動粘度を０．２２ｍｍ２／ｓ以下に低下させて前記溶湯ノズルの目詰まりとブロッキング現象を防止し、製造される銀粉末の粒径を小さくする請求項１〜４のいずれか一項に記載の銀粉末製造方法。 The molten silver flows down from the molten metal nozzle,
By making the temperature of the molten silver 1400 ° C. or higher and 1600 ° C. or lower, the kinematic viscosity of the molten silver is reduced to 0.22 mm 2 / s or lower to prevent clogging and blocking phenomenon of the molten metal nozzle. The silver powder manufacturing method as described in any one of Claims 1-4 which makes the particle size of the silver powder which makes it small.
り、前記噴霧ノズルは軸対称な吸引管を有し、前記吸引管の径及び長さは、噴霧された前記水が前記第１収束部において前記溶融銀を微粒子化し、前記第１収束部を経た前記水が略円錐面に沿って進行し、前記吸引管の内面の第１円環部に当たって反射し、第２略逆円錐面に沿ってその頂部である第２収束部に向かって進行するように設定されることを特徴とする銀粉末製造装置。 A molten metal nozzle for causing the molten silver to flow down in the form of a molten silver column, a spray nozzle for spraying water so as to converge along a substantially inverted conical surface to the first converging part, and a top of the nozzle A silver powder production apparatus having at least a horizontal position adjusting means for setting a position inside the molten silver column, the spray nozzle has an axisymmetric suction pipe, and the diameter and length of the suction pipe are sprayed. Further, the water makes fine particles of the molten silver in the first converging part, and the water passing through the first converging part travels along a substantially conical surface and hits and reflects the first annular part on the inner surface of the suction pipe. The silver powder manufacturing apparatus is set so as to proceed along the second substantially inverted conical surface toward the second converging portion that is the top portion thereof.
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Cited By (5)
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| JP2020045552A (en) * | 2018-09-21 | 2020-03-26 | Tdk株式会社 | Metal powder producing apparatus and metal powder producing method |
| JP2020045553A (en) * | 2018-09-21 | 2020-03-26 | Tdk株式会社 | Metal powder producing apparatus and metal powder producing method |
| WO2021036385A1 (en) * | 2019-08-30 | 2021-03-04 | 厦门金达威维生素有限公司 | Atomizing tray, spray drying atomizer and high viscosity material atomizing method therefor |
| JP2021167456A (en) * | 2020-04-13 | 2021-10-21 | 東京窯業株式会社 | Atomizer |
| JP7470657B2 (en) | 2021-04-06 | 2024-04-18 | 東京窯業株式会社 | Atomization Equipment |
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| CN112475306A (en) * | 2020-11-17 | 2021-03-12 | 江苏威拉里新材料科技有限公司 | Multifunctional gas atomization metal powder bed |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2020045552A (en) * | 2018-09-21 | 2020-03-26 | Tdk株式会社 | Metal powder producing apparatus and metal powder producing method |
| JP2020045553A (en) * | 2018-09-21 | 2020-03-26 | Tdk株式会社 | Metal powder producing apparatus and metal powder producing method |
| JP7110867B2 (en) | 2018-09-21 | 2022-08-02 | Tdk株式会社 | Metal powder manufacturing apparatus and metal powder manufacturing method |
| JP7131245B2 (en) | 2018-09-21 | 2022-09-06 | Tdk株式会社 | Metal powder manufacturing apparatus and metal powder manufacturing method |
| WO2021036385A1 (en) * | 2019-08-30 | 2021-03-04 | 厦门金达威维生素有限公司 | Atomizing tray, spray drying atomizer and high viscosity material atomizing method therefor |
| JP2021167456A (en) * | 2020-04-13 | 2021-10-21 | 東京窯業株式会社 | Atomizer |
| JP7266009B2 (en) | 2020-04-13 | 2023-04-27 | 東京窯業株式会社 | atomizing device |
| JP7470657B2 (en) | 2021-04-06 | 2024-04-18 | 東京窯業株式会社 | Atomization Equipment |
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