# US 12,119,170 B2 · Method for producing a magnetic powder

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- Number: US 12,119,170 B2
- Document ID: US12119170B2
- Status: Granted
- Kind: B2
- Application number: 17/126,230
- Filed: 2020-12-18
- Published: 2021-10-14
- Granted: 2024-10-15
- Earliest claimed: 2018-06-18
- Assignees: ABB Schweiz AG
- Applicants: ABB Schweiz AG
- Inventors: Reinhard Simon; Jacim Jacimovic; Lorenz Herrmann; Felix Greuter; Elio Perigo
- Web page: https://patentgrep.com/patent/US12119170B2

## CPC

- H01F 41/0253: {for manufacturing permanent magnets}
- B22F 1/142: Thermal or thermo-mechanical treatment
- B22F 9/082: {atomising using a fluid (using centrifugal force B22F9/10)}
- C22C 38/005: {containing rare earths, i.e. Sc, Y, Lanthanides}
- G01N 23/20091: Measuring the energy-dispersion spectrum [EDS] of diffracted radiation
- H01F 1/053: containing rare earth metals
- H01J 49/105: {using high-frequency excitation, e.g. microwave excitation, Inductively Coupled Plasma [ICP]}
- B22F 2201/10: Inert gases
- B22F 2201/20: Use of vacuum
- B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer
- C22C 2202/02: Magnetic
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- 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
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

The present disclosure provides a method for producing a magnetic powder and the use of a waste magnetic material for producing isotropic or anisotropic magnets. The method including providing a waste magnetic material including a waste magnetic chemical composition, analyzing the waste magnetic material to obtain information about the waste magnetic chemical composition thereof, adjusting the waste magnetic chemical composition to a target magnetic chemical composition to obtain an adjusted waste magnetic material, and atomizing the adjusted waste magnetic material to obtain the magnetic powder.

## Claims

### Claim 1

A method for producing a magnetic powder, the method comprising:
a) providing a waste magnetic material comprising a waste magnetic chemical composition;
b) analysing the waste magnetic material to obtain the waste magnetic chemical composition thereof, wherein the waste magnetic chemical composition includes identities and/or relative proportions of chemical elements of which the waste magnetic material is composed;
c) adjusting the waste magnetic chemical composition to a target magnetic chemical composition to obtain an adjusted waste magnetic material by at least one of:
adding a difference amount of at least one chemical element to the waste magnetic material; or
mixing the difference amount of the at least one of the chemical element and the waste magnetic material,
wherein adjusting the waste magnetic chemical composition further comprises melting the difference amount of the at least one chemical element and the waste magnetic material; and
d) atomizing the adjusted waste magnetic material obtained in act c) to obtain the magnetic powder,
wherein adjusting the waste magnetic chemical composition to a target magnetic chemical composition to obtain an adjusted waste magnetic material in act c) further comprises the act of:
c1) calculating at least one difference amount between at least one chemical element in the waste magnetic chemical composition and the at least one chemical element in the target magnetic chemical composition.

### Claim 2 (depends on 1)

The method according to claim 1, wherein providing the waste magnetic material in act a) comprises at least one of the acts:
a1) disassembling an electrical device containing a waste magnetic material; and
a2) separating a waste magnetic material from other non-magnetic components of an electrical device.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the electrical device comprises low voltage motors, wind turbine generators, and servomotors.

### Claim 4 (depends on 1)

The method according claim 1, wherein the method further comprises an act e) performing a heat treatment to the magnetic powder.

### Claim 5 (depends on 4)

The method according to claim 4, wherein act e) comprises heating magnetic powder under vacuum or under an inert atmosphere at temperatures between 200 and 800° C. and/or for the time period between 1 and 300 minutes.

### Claim 6 (depends on 4)

The method according to claim 4, wherein act e) comprises heating magnetic powder under vacuum or under an inert atmosphere at temperatures between 400 and 600° C. and/or for the time period between 15 and 180 minutes.

### Claim 7 (depends on 1)

The method according claim 1, wherein atomizing the adjusted waste magnetic material in act d) is conducted under inert atmosphere comprising at least one of argon or helium.

### Claim 8 (depends on 1)

The method according claim 1, wherein the at least one chemical element comprises a rare-earth element.

### Claim 9 (depends on 1)

The method according to claim 1, wherein analysing the waste magnetic material to obtain the waste magnetic chemical composition thereof in act b) is conducted by using a chemical analytical method comprising inductively coupled plasma mass spectrometry or energy-dispersive X-ray spectroscopy.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the act of melting the difference amount of the at least one chemical element and the waste magnetic material is conducted at temperatures between 800 and 1300° C.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the magnetic powder comprises spherical magnetic particles.

### Claim 12 (depends on 11)

The method according to claim 11, wherein the spherical magnetic particles have an average diameter in the range of 1 to 500 μm.

### Claim 13 (depends on 12)

The method according to claim 12, wherein the spherical magnetic particles have an average coercivity in the range of 50 to 2500 kA/m.

### Claim 14 (depends on 12)

The method according to claim 12, wherein the spherical magnetic particles have an average coercivity in the range of 900 to 1500 kA/m.

### Claim 15 (depends on 11)

The method according to claim 11, wherein the spherical magnetic particles have an average coercivity in the range of 50 to 2500 kA/m.

### Claim 16 (depends on 11)

The method according to claim 11, wherein the spherical magnetic particles have an average diameter in the range of 10 to 150 μm.

### Claim 17 (depends on 11)

The method according to claim 11, wherein the spherical magnetic particles have an average coercivity in the range of 900 to 1500 kA/m.

### Claim 18 (depends on 1)

The method according to claim 1, wherein the act of melting the difference amount of the at least one chemical element and the waste magnetic material is conducted at temperatures between 1000 and 1100° C.