Technetium recovery from high alkaline solution

Patent metadata

Field	Value
Publication number	US-9388478-B1
Application number	US-201414576362-A
Country	US
Kind code	B1
Filing date	Dec 19, 2014
Priority date	Dec 19, 2014
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

First claim

What is claimed is:

1. A method for recovering technetium from a solution comprising:
combining the solution with a reductant, the solution having a pH of 12 or greater, the solution comprising dissolved technetium, the reductant being capable at the pH of the solution of reducing the oxidation state of the dissolved technetium to an oxidation state at which the technetium is insoluble in the solution and precipitates out of the solution;
adding to the solution or forming in the solution an adsorbent, the adsorbent being capable at the pH of the solution of adsorbing the precipitated technetium.

2. The method of claim 1 , wherein the solution has a pH of 13 or greater.

3. The method of claim 1 , wherein the solution has a pH of 14 or greater.

4. The method of claim 1 , wherein the technetium batch distribution coefficient for the method is about 400 mL/g or greater.

5. The method of claim 1 , wherein the decontamination factor of the method with regard to technetium is about 2.2 or greater.

6. The method of claim 1 , wherein the pH of the solution is not altered during the method.

7. The method of claim 1 , wherein the method is carried out at a temperature of about 40° C. or less.

8. The method of claim 1 , wherein the method is carried out at ambient temperature.

9. The method of claim 1 , wherein the method is carried out at atmospheric conditions.

10. The method of claim 1 , wherein the method is carried out in an inert atmosphere.

11. The method of claim 1 , wherein the reductant comprises stannous ion.

12. The method of claim 1 , wherein the reductant comprises hydrazine ion.

13. The method of claim 1 , wherein the reductant comprises dithionite ion.

14. The method of claim 1 , wherein the reductant is included in the solution at a concentration of about 1 M or less.

15. The method of claim 1 , wherein the adsorbent comprises a compound that is formed in the solution.

16. The method of claim 15 , wherein the adsorbent comprises iron hydroxide.

17. The method of claim 1 , wherein the adsorbent comprises zirconium dioxide.

18. The method of claim 1 , wherein the adsorbent comprises ferrous oxalate.

19. The method of claim 1 , wherein the adsorbent comprises molybdate ion.

20. The method of claim 1 , wherein the adsorbent is added to or formed in the solution at a concentration of about 0.25 mg/mL of the solution or greater.

21. The method of claim 1 , wherein the adsorbent comprises iron, the iron being added to the solution at a concentration of about 0.1 grams per liter of solution or greater.

22. The method of claim 1 , the method further comprising combining an enhancing agent to the solution.

23. The method of claim 22 , wherein the enhancing agent comprises sulfide ion.

24. The method of claim 1 , wherein the solution comprises liquid waste from a nuclear waste processing system.

Assignees

• Savannah River Nuclear Solutions Llc

Inventors

• Nash Charles A

Classifications

• C22B61/00 Primary

  Obtaining metals not elsewhere provided for in this subclass (iron C21) · CPC title

• B01D15/00

  Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor · CPC title

• C01G99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• Y02P10/20

  Recycling · CPC title

• C01G99/003

  Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title