Process for recycling rare earth magnets

Patent metadata

Field	Value
Publication number	US-10323300-B1
Application number	US-201615254232-A
Country	US
Kind code	B1
Filing date	Sep 1, 2016
Priority date	Sep 25, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A method to separate rare earth material from a rare earth magnet. At least one embodiment comprises a method that heats a provided rare earth magnet to at least 600° C. whereby the rare earth magnet absorbs a dry gas. Separated rare earth materials are created. Magnetic rare earth materials are produced from the separated rare earth materials.

First claim

We claim:

1. A method to separate rare earth material from a rare earth magnet, the method comprising the steps of:
a. providing a rare earth magnet and an oxygen getter;
b. providing an inert gas at said provided rare earth magnet and oxygen getter;
c. exposing said provided rare earth magnet and oxygen getter to a vacuum for a period of time sufficient to substantially purify said rare earth magnet;
d. exposing said provided rare earth magnet and oxygen getter to a continuous flow of dry gas;
e. heating said exposed rare earth magnet and oxygen getter to at least 600° C. whereby said exposed rare earth magnet absorbs said dry gas causing separated rare earth materials and residual materials to form;
f. maintaining said separated rare earth materials in an environment wherein impurities that prevent the rare earth magnet from absorbing said dry gas during said steps of exposing and heating are removed; and
g. producing magnetic rare earth materials from said separated rare earth materials formed by said step of heating by exposing said separated rare earth materials to a vacuum and heating said separated rare earth materials to a temperature sufficient to desorb said dry gas.

2. The method of claim 1 wherein said dry gas is a high purity gas.

3. The method of claim 1 wherein said dry gas is H 2 .

4. The method of claim 1 wherein said inert gas comprises an argon mixture.

5. The method of claim 1 wherein an outer material substantially surrounds said provided rare earth magnet.

6. The method of claim 5 wherein said outer material is fractured prior to said step of exposing said provided rare earth magnet to a dry gas.

7. The method of claim 1 wherein said step of maintaining said separated rare earth materials further includes:
a. exposing said provided rare earth magnet to a vacuum for a period of time sufficient to substantially purify said provided rare earth magnet prior to exposing said provided rare earth magnet to said dry gas.

8. The method of claim 1 further comprising the step of:
a. cooling the separated rare earth materials prior to said step of producing magnetic rare earth materials.

9. The method of claim 1 further comprising the step of:
a. collecting said separated rare earth materials from said residual materials prior to said step of producing magnetic rare earth materials.

10. The method of claim 1 wherein said magnetic rare earth materials are a fine powder, the fine powder comprising individual grains of less than 10 micron in diameter.

11. A method to separate rare earth material from a rare earth magnet, the method comprising the steps of:
a. providing a rare earth magnet and an oxygen getter, the rare earth magnet having an outer material substantially surrounding said rare earth magnet;
b. fracturing said outer material;
c. providing an inert gas at said provided rare earth magnet and oxygen getter;
d. exposing said provided rare earth magnet and oxygen getter to a vacuum for a period of time sufficient to substantially purify said rare earth magnet;
e. exposing said provided rare earth magnet and oxygen getter to a continuous flow of dry gas;
f. heating said exposed rare earth magnet and oxygen getter to at least 600° C. whereby said exposed rare earth magnet absorbs said dry gas causing separated rare earth materials and residual materials to form;
g. maintaining said separated rare earth materials in an environment wherein impurities that prevent the rare earth magnet from absorbing said dry gas during said steps of exposing and heating are removed; and
h. producing magnetic rare earth materials from said separated rare earth materials formed by said step of heating by exposing said separated rare earth materials to a vacuum and heating said separated rare earth materials to a temperature sufficient to desorb said dry gas.

Assignees

• Us Energy
• Us Dept Energy

Inventors

• Tripathy Prahbat K
• Swank William D
• Haggard Delon C
• Lister Tedd E
• Peterson Eric S

Classifications

• B22F8/00

  Manufacture of articles from scrap or waste metal particles · CPC title

• H01F1/0573

  obtained by reduction or by hydrogen decrepitation or embrittlement · CPC title

• C22B1/005

  Preliminary treatment of scrap (C22B1/02 - C22B1/26 take precedence) · CPC title

• H01F41/0253

  for manufacturing permanent magnets · CPC title

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title