TREATMENT METHOD OF SPENT URANIUM CATALYST

• US 20140096646A1
• Filed: 08/06/2013
• Published: 04/10/2014
• Est. Priority Date: 10/08/2012
• Status: Active Grant

• Current Assignee: Korea Hydro and Nuclear Power Company Limited (Government of South Korea), Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Original Assignee: Korea Hydro and Nuclear Power Company Limited (Government of South Korea), Korea Atomic Energy Research Institute (Government of The Republic of Korea)
• Inventors: Kim, Kwang-Wook, Lee, Eil-Hee, Lee, Keun-Young, Moon, Jei-Kwon, Chung, Dong-Yong
• Granted Patent: US 9,181,605 B2
• Time in Patent Office: Days
• US Class Current: 75/398
• CPC Class Codes: B01D 61/44 Ion-selective electrodialysis
• CPC Class Codes: C22B 60/0217 by wet processes
• CPC Class Codes: C22B 60/0278 by chemical methods C22B60/0256, C22B60/026, C22B60/0265 take precedence
• CPC Class Codes: G21F 9/06 Processing separating different isotopes of the same chemical element B01D59/00
• CPC Class Codes: G21F 9/28 Treating solids
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y02W 30/50 Reuse, recycling or recovery technologies

Abstract

The present invention relates to a treatment method of spent uranium catalyst, and more specifically, to a method which can considerably reduce the volume of the spent uranium catalyst to be disposed of and simultaneously minimize secondary wastes that can be generated during the process of treating the spent uranium catalyst.

Claims

1. A treatment method of a spent uranium catalyst, comprising steps of:

dissolving the spent uranium catalyst in an alkaline solution, taking the undissolved spent uranium catalyst out from the solution and dissolving the undissolved spent uranium catalyst further in an acidic solution (Step

     1);

precipitating Si, a spent catalyst supporter material, by adding carbonate and hydrogen peroxide into the alkaline solution obtained at Step 1 and adjusting pH to 6˜

10 or by adding one selected from the group consisting of MgCl₂, CaCl₂, KCl, and NaCl while lowering pH of the alkaline solution obtained at Step 1 to pH 4 or below, and precipitating metal materials of the spent catalyst by adding hydrogen peroxide into a mixture solution of the acidic solution obtained at Step 1 and a supernatant of the alkaline solution after the Si is precipitated while adjusting pH(Step

     2); and

removing uranium from the supernatant of the mixture solution after the metal materials are precipitated (Step

     3).

2. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the spent uranium catalyst is in a form in which a Si supports U_wSb_xM_yO_z (M=one or more selected from among Fe, Al, Mo, V, and Bi, and w, x, y, and z represent a molar ratio to construct oxide).

3. The treatment method of the spent uranium catalyst as set forth in claim 1, comprising repeating a process of precipitating the Si, the spent catalyst supporter material, by adding carbonate and hydrogen peroxide into the alkaline solution obtained at Step 1 and adjusting the pH of the solution to pH 6˜

10.

4. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the pH of the mixture solution of the acidic solution obtained at Step 1 and the supernatant of the alkaline solution after the Si is precipitated, is adjusted up to pH 3˜

4.

5. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the acidic solution is one or more selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, and phosphoric acid.

6. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the alkaline solution is one or more selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide.

7. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the Step 1 is performed repeatedly.

8. The treatment method of the spent uranium catalyst as set forth in claim 1, after the Step 1, further comprising a step of thermally treating the spent uranium catalyst remaining undissolved.

9. The treatment method of the spent uranium catalyst as set forth in claim 8, wherein the thermally treating is performed at a temperature of 500˜

800°

C.

10. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the carbonate at the Step 2 is sodium carbonate (Na₂CO₃).

11. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the metal material precipitated at the Step 2 is Fe or U.

12. The treatment method of the spent uranium catalyst as set forth in claim 1, after the Step 2, further comprising a process of thermally treating wastes as obtained.

13. The treatment method of the spent uranium catalyst as set forth in claim 12, wherein the thermally treating is performed at a temperature of 500800°

C.

14. The treatment method of the spent uranium catalyst as set forth in claim 1, wherein the removing of the uranium at the Step 3 is performed by using an adsorbent.

15. The treatment method of the spent uranium catalyst as set forth in claim 14, wherein the adsorbent used at the Step 3 is activated carbon or biosorbent.

16. The treatment method of the spent uranium catalyst as set forth in claim 15, wherein the biosorbent is one selected from the group consisting of sea mustard, kelp, and gulfweed.

17. The treatment method of the spent uranium catalyst as set forth in claim 14, further comprising a step of igniting the adsorbent used at the Step 3 at a temperature of 500˜

800°

C.

18. The treatment method of the spent uranium catalyst as set forth in claim 1, further comprising a step of injecting a solution from which the uranium is removed at the Step 3 into an electrodialyzer for recovering the acidic solution and the alkaline solution (Step 4).

19. The treatment method of the spent uranium catalyst as set forth in claim 18, further comprising a step of recycling the acidic solution and the alkaline solution recovered from the Step 4 to the Step 1.

20. The treatment method of the spent uranium catalyst as set forth in claim 18, wherein the Step 4 injects one or more selected from the group consisting of sodium hydroxide, lithium hydroxide, potassium hydroxide, and ammonium hydroxide in between a cathode and a cation exchange membrane of the electrodialyzer which is equipped with the cation exchange membrane and an anion exchange membrane;

injects the solution from which the uranium is eliminated in between the anion exchange membrane and cation exchange membrane;

injects one or more selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, and phosphoric acid in between the anion exchange membrane and the anode; and

electrolyzes water by applying a voltage of 5˜

30V to recover the acidic solution and the alkaline solution.