Recovering rare earth metals from magnet scrap

Patent metadata

Field	Value
Publication number	US-2017016088-A1
Application number	US-201614999802-A
Country	US
Kind code	A1
Filing date	Jun 28, 2016
Priority date	Jul 15, 2015
Publication date	Jan 19, 2017
Grant date	—

Abstract

A method is provided for treating a rare earth metal-bearing scrap material by melting an extractant selected from the group consisting of bismuth (Bi) and lead (Pb) and contacting the melted extractant and the scrap material at a temperature and time to recover at least one of the light rare earth metal content and the heavy rare earth metal content as a metallic extractant alloy, which can be subjected to vacuum distillation or sublimation to recover the rare earth metal(s). The method can be practiced to recover the light rare earth metal content and the heavy rare earth metal content concurrently in a one-step process or separately and sequentially in a two-step process.

First claim

We claim:

1 . A method of treating a rare earth metal-bearing scrap material, comprising melting an extractant selected from the group consisting of bismuth (Bi) and lead (Pb) and contacting the melted extractant and the scrap material at a temperature and time to recover at least one of a light rare earth metal content and a heavy rare earth metal content of the scrap material as part of a metallic extractant alloy.

2 . The method of claim 1 wherein the light rare earth metal content and the heavy rare earth metal content are recovered concurrently in a one-step process.

3 . The method of claim 1 wherein the light rare earth metal content and the heavy rare earth metal content are recovered separately in sequence in different extractants in a two-step process.

4 . The method of claim 1 wherein the extractant comprises at least 50% by weight Bi.

5 . The method of claim 4 wherein the extractant comprises at least 75% by weight Bi.

6 . The method of claim 5 wherein the extractant comprises at least 98% by weight Bi.

7 . The method of claim 1 wherein the extractant comprises Bi in the temperature range of greater than 271 degrees C. to 1300 degrees C.

8 . The method of claim 1 wherein the extractant alloy comprises at least one of the light rare earth metal content and the heavy rare earth metal content and at least one of Bi and Pb.

9 . The method of claim 1 wherein the rare earth metal-bearing scrap material comprises a transition metal, a light rare earth metal, and a heavy rare earth metal.

10 . The method of claim 1 wherein the light rare earth metal content is selected from the group consisting of Nd, Pr, Sm and Gd and the heavy rare earth metal content is selected from the group consisting of Dy, Tb, and Ho.

11 . The method of claim 1 wherein the extractant alloy is subjected to vacuum distillation.

12 . A method of treating a rare earth metal-bearing scrap material that comprises a transition metal, a light rare earth metal, and a heavy rare earth metal, comprising melting an extractant selected from the group consisting of bismuth (Bi) and lead (Pb) and contacting the melted extractant and the scrap material at a temperature and time to recover the light rare earth metal and the heavy rare earth metal concurrently in a one-step process as a metallic extractant alloy.

13 . The method of claim 12 including selectively removing the extractant from the extractant alloy to recover the light rare earth metal and the heavy rare earth metal.

14 . The method of claim 12 wherein the extractant comprises at least 50% by weight Bi.

15 . The method of claim 14 wherein the extractant comprises at least 75% by weight Bi.

16 . The method of claim 15 wherein the extractant comprises at least 98% by weight Bi.

17 . The method of claim 12 wherein the extractant comprises Bi in the temperature range of greater than 271 degrees C. to 1300 degrees C.

18 . The method of claim 12 wherein the light rare earth metal content is selected from the group consisting of Nd, Pr, Sm and Gd and the heavy rare earth metal content is selected from the group consisting of Dy, Tb, and Ho.

19 . A method of treating a rare earth metal-bearing scrap material that comprises a transition metal, a light rare earth metal, and a heavy rare earth metal, comprising: (a) melting a first extractant selected from the Group IIA metals of the Periodic Table and contacting the scrap material and the molten first extractant at a temperature and time to recover the light rare earth metal content as a first metallic extractant alloy, leaving a remnant alloy rich in heavy rare earth metal content; and (b) melting a second extractant selected from the group consisting of bismuth (Bi) and lead (Pb) and contacting the remnant alloy and the molten second extractant at a temperature and time to recover the heavy rare earth metal content as a second metallic extractant alloy.

20 . The method of claim 19 including selectively removing the first extractant from the first extractant alloy to recover the light rare earth metal.

21 . The method of claim 19 including selectively removing the second extractant from the second extractant alloy to recover the heavy rare earth metal.

22 . The method of claim 19 wherein the extractant comprises at least 50% by weight Bi.

23 . The method of claim 22 wherein the extractant comprises at least 75% by weight Bi.

24 . The method of claim 23 wherein the extractant comprises at least 98% by weight Bi.

25 . The method of claim 19 wherein the first extractant comprises Mg and the second extractant comprises Bi.

26 . The method of claim 19 wherein the first extractant alloy comprises the light rare earth metal and Mg.

27 . The method of claim 19 wherein the second extractant alloy comprises the heavy rare earth metal and Bi.

28 . The method of claim 19 wherein the light rare earth metal content is selected from the group consisting of Nd, Pr, and Gd and the heavy rare earth metal content is selected from the group consisting of Dy, Tb, and Ho.

29 . A metallic alloy including at least one of Bi and Pb and at least one of rare earth metal.

Assignees

• Univ Iowa State Res Found Inc

Inventors

• Ott Ryan T
• Mccallum Ralph W

Classifications

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title

• C22B7/006

  Wet processes · CPC title

• C22B7/005

  Separation by a physical processing technique only, e.g. by mechanical breaking · CPC title

• B01D7/00

  Sublimation (B01D8/00 takes precedence; freeze-drying F26) · CPC title

• B01D3/106

  with the use of a pump for creating vacuum and for removing the distillate · CPC title