Method for recovering rare earth element

Patent metadata

Field	Value
Publication number	US-9347115-B2
Application number	US-201214356322-A
Country	US
Kind code	B2
Filing date	Nov 1, 2012
Priority date	Nov 14, 2011
Publication date	May 24, 2016
Grant date	May 24, 2016

Abstract

The object of the present invention is to provide a method for recovering a rare earth element, which is capable of efficiently recovering a rare earth element with high recovery rate without using any expensive chemicals, solvents or the like. In the present invention, a water-soluble salt other than sulfate ions is allowed to coexist with an aqueous solution that contains a rare earth element, and then an alkali metal sulfate is added to the aqueous solution, thereby producing a precipitate of a double sulfate of the rare earth element.

First claim

The invention claimed is:

1. A method for recovering a rare earth element comprising the steps of:
providing an aqueous solution containing (i) a rare earth element and (ii) a water-soluble salt that is one or more members selected from the group consisting of a chloride, a perchlorate, a chlorate, a bromate, a bromide, a periodate, an iodate, and an iodide, the water-soluble salt being present in the aqueous solution at an anionic ion concentration of 4 to 10 mol/l; and
adding an alkali metal sulfate thereto so that a precipitate of a double sulfate of the rare earth element is generated.

2. The method for recovering a rare earth element according to claim 1 , wherein the water-soluble salt is a salt having divalent cations in the aqueous solution.

3. The method for recovering a rare earth element according to claim 2 , wherein the water-soluble salt is nickel chloride.

4. The method for recovering a rare earth element according to claim 1 , wherein by adding the alkali metal sulfate, a sulfate ion concentration in the aqueous solution is set to 50 g/l or more.

5. The method for recovering a rare earth element according to claim 1 , wherein the alkali metal sulfate is sodium sulfate.

6. The method for recovering a rare earth element according to claim 1 , wherein a temperature of the aqueous solution is 50° C. or more when the alkali metal sulfate is added thereto so that the double sulfate precipitate of the rare earth element is generated.

7. The method for recovering a rare earth element according to claim 6 , wherein the temperature of the aqueous solution is 80° C. or more when the alkali metal sulfate is added thereto.

8. The method for recovering a rare earth element according to claim 1 , wherein the rare earth element is a heavy rare earth element.

9. The method for recovering a rare earth element according to claim 1 , wherein the water-soluble salt is NiCl 2 , LiCl, CaCl 2 , or MgCl 2 .

10. The method for recovering a rare earth element according to claim 1 , wherein the alkali metal sulfate is potassium sulfate.

11. A method for recovering a rare earth element, the method comprising:
adding a water-soluble salt that is one or more members selected from the group consisting of a chloride, a perchlorate, a chlorate, a bromate, a bromide, a periodate, and iodate, and an iodide to an aqueous solution containing a rare earth element, the water-soluble salt being present in the resulting aqueous solution at an anionic ion concentration of 4 to 10 mol/l; and then
adding an alkali metal sulfate thereto so that a precipitate of a double sulfate of the rare earth element is generated.

12. The method for recovering a rare earth element according to claim 11 , wherein the water-soluble salt is a salt having divalent cations in the aqueous solution.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Maeba Kazunari
• Kawakami Yukie
• Kudo Keiji
• Takano Masatoshi
• Ishida Hitoshi
• Asano Satoshi
• Tanaka Masahiro

Classifications

• C22B7/007

  by acid leaching · CPC title

• C22B3/44

  by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42) · CPC title

• Y02P10/234

  Cross-Sectional Technologies · mapped topic

• C22B59/00 Primary

  Obtaining rare earth metals · CPC title

• Y02P10/20

  Recycling · CPC title