1999 Fiscal Year Final Research Report Summary
Metal Powder Production by Vapor Explosion
| Project/Area Number |
09450094
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
ITO Takehiro Kyushu University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (20037740)
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| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Hiromi Kyushu University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (10117103)
TANAKA Katsunori Kyushu University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (40037833)
TAKATA Yasuyuki Kyushu University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (70171444)
OGURA Kuniaki Kawasaki Steel Corporation, Senior Scientist, 技術研究所, 主任研究員
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| Project Period (FY) |
1997 – 1999
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| Keywords | Vapor explosion / Water atomization process / Phase change / Metal powder / Fragmentation / Zinc oxide |
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| Research Abstract |
Thermal interaction between molten metal drop and water has been investigated experimentally. The purpose of this study is to disclose the mechanisms of fragmentation and rapid cooling in steel-powder-making process, so-called water atomization process. Experimental apparatus consists of heating unit, water injection system and powder-collection part. Mainly, induction heating is used to melt the metals. Temperatures of the molten metal are measured by the radiation thermometer.
First, The second, water atomization experiments have been performed using a molten iron drop. Two types of water nozzle were used. One is straight nozzle and the other is flat nozzle. Four nozzles of each type were mounted on the experimental unit with some injection angle. The direction of four nozzles is focused to the stream center, to which the molten metal is dropped. Influence of water temperature, type and angle of nozzles on the shape, the size distribution and the yield rate of powders were investigated.
The quartz glass nozzles for molten iron were used to control the dropping position with higher certainty. The exit diameters of the nozzles are 1.5, 2.5, 3.5 and 5.5 mmφ. The use of these nozzles brought us good yield rate and the size of produced powders ranges mainly below 100μm.
As a new attempt, we tried to develop a zinc oxide power production process. In the conventional process, auxiliary heat is needed to vaporize zinc metal. By the thermodynamic consideration, it is possible to realize a spontaneous oxidizing process by recovering heat of reaction. We have made a preliminary experiment of zinc oxide production. Duration of spontaneous reaction was 15min in the condition of air flow rate of 10L/min, argon flow rate of 5L/min and heat input of 1100W. By microscopic observation, the size of power produced in the present study is larger than that of commercially available power. The recovery of heat is estimated to be 280W.
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