# US 2019/0168183 A1 · Ferromagnetic-particle manufacturing apparatus

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- Number: US 2019/0168183 A1
- Document ID: US20190168183A1
- Status: Published application
- Kind: A1
- Application number: 16/272,877
- Filed: 2019-02-11
- Published: 2019-06-06
- Earliest claimed: 2013-10-07
- Assignees: Dai-Ichi High Frequency Co., Ltd.
- Applicants: Dai-Ichi High Frequency Co., Ltd.
- Inventors: Kotaro HIRAYAMA; Shota TANOUE
- Web page: https://patentgrep.com/patent/US20190168183A1

## CPC

- B01J 19/126: {Microwaves}
- B01J 19/02: Apparatus characterised by being constructed of material selected for its chemically-resistant properties
- B01J 19/06: Solidifying liquids (making microcapsules B01J13/02)
- B22F 1/05: Metallic powder characterised by the size or surface area of the particles
- B22F 9/24: starting from liquid metal compounds, e.g. solutions
- C01G 49/0018: {Mixed oxides or hydroxides, (C01G49/0009 takes precedence)}
- C01G 49/08: Ferroso-ferric oxide [Fe3O4]
- C01G 53/40: Complex oxides containing nickel and at least one other metal element
- H01F 1/20: in the form of particles, e.g. powder (H01F1/147 takes precedence)
- H05B 6/108: {for heating a fluid}
- H05B 6/806: {for laboratory use}
- B01J 2219/0204: comprising coatings on the surfaces in direct contact with the reactive components
- B01J 2219/0871: Heating or cooling of the reactor
- B01J 2219/0877: Liquid
- B01J 2219/1215: Single reactor
- B01J 2219/1245: Parts of the reactor being microwave absorbing, dielectric
- B22F 2009/245: {Reduction reaction in an Ionic Liquid [IL]}
- B22F 2301/15: Nickel or cobalt
- B22F 2301/35: Iron
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- C01P 2006/42: Magnetic properties
- C22C 2202/02: Magnetic
- H05B 2214/04: Heating means manufactured by using nanotechnology
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A method for manufacturing a ferromagnetic-particle includes preparing a manufacturing apparatus including a single mode cavity that resonates with a microwave of a predetermined wavelength; a microwave oscillator electrically connected to the single mode cavity and configured to introduce the microwave of a predetermined wavelength into the single mode cavity; a pipe disposed to pass linearly through an inside of the single mode cavity, the pipe being formed of a dielectric material; and a pump configured to introduce, from one end of the pipe, an alkaline reaction liquid in which metal ions of a ferromagnetic metal and hydroxide ions are dissolved; and reacting the reaction liquid in the pipe, introduced by the pump, by introducing the microwave into the single mode cavity so as to generate the ferromagnetic-particle in the pipe.

## Claims

### Claim 1

A method for manufacturing a ferromagnetic-particle comprising the steps of:
preparing a manufacturing apparatus including:
a single mode cavity that resonates with a microwave of a predetermined wavelength;
a microwave oscillator electrically connected to the single mode cavity and configured to introduce the microwave of a predetermined wavelength into the single mode cavity; a pipe disposed to pass linearly through an inside of the single mode cavity, the pipe being formed of a dielectric material; and
a pump configured to introduce, from one end of the pipe, an alkaline reaction liquid in which metal ions of a ferromagnetic metal and hydroxide ions are dissolved; and
reacting the reaction liquid in the pipe, introduced by the pump, by introducing the microwave into the single mode cavity so as to generate the ferromagnetic-particle in the pipe.

### Claim 2 (depends on 1)

The method according to claim 1, wherein an axial length of the pipe is 20 mm to 200 mm.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the metal ions of the ferromagnetic metal are either or both of iron ions and nickel ions.

### Claim 4 (depends on 1)

The method according to claim 1, further comprising the step of dissolving sodium hydroxide in the reaction liquid.

### Claim 5 (depends on 1)

The method according to claim 1, wherein an internal diameter of the pipe is 0.3 mm to 5.0 mm.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the pump includes a first pump sending a metal salt solution containing metal ions and a second pump sending an alkaline solution containing hydroxide ions.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the manufacturing apparatus includes an impedance measuring device configured to measure an impedance of the single mode cavity, and
wherein the method further comprises the step of controlling a pump-flowrate based on a measurement result of the impedance, such that the impedance of the single mode cavity becomes a predetermined value or more.

### Claim 8 (depends on 7)

The method according to claim 7, wherein:
when a current measurement result of the impedance is larger than a stored previous measurement result, the flowrate of the reaction liquid introduced into the pipe is controlled to gradually increase, and
when the current measurement result of the impedance is smaller than the stored previous measurement result, the flowrate of the reaction liquid introduced into the pipe is controlled to gradually decrease.