US 11,986,885 B2
Fine particle production apparatus and fine particle production method
Yasunori Tanaka, Kanazawa (JP); Naoto Kodama, Kanazawa (JP); Kazuki Onda, Kanazawa (JP); Shu Watanabe, Saitama (JP); Keitaro Nakamura, Saitama (JP); and Shiori Sueyasu, Saitama (JP)
Assigned to NATIONAL UNIVERSITY CORPORATION KANAZAWA UNIVERSITY, Ishikawa (JP); and NISSHIN SEIFUN GROUP INC., Tokyo (JP)
Appl. No. 17/615,775
Filed by NATIONAL UNIVERSITY CORPORATION KANAZAWA UNIVERSITY, Kanazawa (JP); and NISSHIN SEIFUN GROUP INC., Tokyo (JP)
PCT Filed Jun. 4, 2020, PCT No. PCT/JP2020/022164
§ 371(c)(1), (2) Date Dec. 1, 2021,
PCT Pub. No. WO2020/246551, PCT Pub. Date Dec. 10, 2020.
Claims priority of application No. 2019-105218 (JP), filed on Jun. 5, 2019.
Prior Publication US 2022/0219236 A1, Jul. 14, 2022
Int. Cl. B22F 9/14 (2006.01); B22F 9/12 (2006.01); H05H 1/42 (2006.01)
CPC B22F 9/14 (2013.01) [B22F 9/12 (2013.01); H05H 1/42 (2013.01); B22F 2202/13 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A fine particle production method using a thermal plasma flame generated inside a plasma torch,
there being provided a first coil surrounding a periphery of the plasma torch, a second coil disposed under the first coil and surrounding the periphery of the plasma torch, a first power source section supplying the first coil with first high frequency current amplitude-modulated, and a second power source section supplying the second coil with second high frequency current amplitude-modulated, the first coil and the second coil being arranged side by side in a longitudinal direction of the plasma torch, and the thermal plasma flame being generated by the first power source section and the second power source section, the method comprising:
a first step of supplying feedstock for fine particle production to the thermal plasma flame generated inside the plasma torch; and
a second step of evaporating the feedstock by use of the thermal plasma flame to transform the feedstock into a mixture in a gas phase state and cooling the mixture, wherein in the first step and the second step, the first power source section supplies the first coil with the first high frequency current amplitude-modulated, the second power source section supplies the second coil with the second high frequency current amplitude-modulated, and a degree of modulation of the first high frequency current is smaller than that of the second high frequency current,
wherein the first high frequency current supplied to the first coil by the first power source section has a region where current amplitude of the first high frequency current is high and a region where a current amplitude of the first high frequency current is lower than that in the region where the current amplitude of the first high frequency current is high, and the second high frequency current supplied to the second coil by the second power source section has a region where a current amplitude of the second high frequency current is high and a region where the current amplitude of the second high frequency current is lower than that in the region where the current amplitude of the second high frequency current is high, and
wherein in the first step, the first high frequency current supplied to the first coil by the first power source section and the second high frequency current supplied to the second coil by the second power source section are supplied at a same timing, and an amount of supply of the feedstock is increased in each region where the current amplitude of the first high frequency current and the region where the current amplitude of the second high frequency current are high.