Process and composition for the immobilization of high alkaline radioactive and hazardous wastes in silicate-based glasses

• US 8,115,044 B2
• Filed: 03/20/2007
• Issued: 02/14/2012
• Est. Priority Date: 03/20/2006
• Status: Expired due to Fees

• Current Assignee: Geomatrix Solutions, Inc.
• Original Assignee: Geomatrix Solutions, Inc.
• Inventors: Chekhmir, Anatoly, Gribetz, Arthur
• Primary Examiner(s): Mayes, Melvin
• Assistant Examiner(s): GREGORIO, GUINEVER S
• Application Number:
  US11/723,541
• Publication Number:
  US 20080020918A1
• Time in Patent Office: 1,792 Days
• Field of Search: None
• US Class Current: 588/11
• CPC Class Codes: B09B 3/29 involving a melting or softening step
• CPC Class Codes: C03C 1/002 Use of waste materials, e.g. slags
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: G21F 9/16 by fixation in stable solid media G21F9/305 takes precedence
• CPC Class Codes: G21F 9/305 Glass or glass like matrix C03B5/005 takes precedence; compositional aspects C03C

Abstract

The present invention provides processes to immobilize high alkaline radioactive and/or hazardous waste in a silicate-based glass, the waste containing one or more of radionuclides, hazardous elements, hazardous compounds, and/or other compounds. The invention also provides silicate-based glass compositions for use in immobilizing radioactive and/or hazardous waste.

Claims

1. A silicate-based glass comprising:

rock-forming components selected from the group consisting of SiO₂, Al₂O₃, ZrO₂, alkaline earth oxides, alkaline oxides and mixtures thereof; and

glass-forming components selected from the group consisting of SiO₂, Al₂O₃, ZrO₂, B₂O₃, P₂O₅, TiO₂, Li₂O, F, alkaline earth oxides, alkaline oxides and mixtures thereof;

said silicate-based glass consisting essentially of;

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O) and divalent cation oxides (RO);

about 1 part in weight percent of trivalent cation oxides (R₂O₃);

about 1 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂) and pentavalent cation oxides (R₂O₅); and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

2. The silicate-based glass of claim 1, wherein the ratio between the rock-forming components of the glass formed, approximates the ratio between the main components of natural high alkaline ultrabasic rock.

3. The silicate-based glass of claim 2, wherein the rock-forming components of

the said silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O) and divalent cation oxides (RO);

about 1 part in weight percent of trivalent cation oxides (R₂O₃);

about 2 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂) and pentavalent cation oxides (R₂O₅); and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

4. The silicate-based glass of claim 2, wherein the rock-forming components of the silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O), including alkaline oxides, and divalent cation oxides (RO), including alkaline earth oxides;

about 1 part in weight percent of trivalent cation oxides (R₂O₃), wherein said trivalent cation oxides comprise aluminum and ferric oxide;

about 2 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂), including silicon, zirconium and titanium, and pentavalent cation oxides (R₂O₅), including and phosphorus oxide; and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

5. The silicate-based glass of claim 1, wherein the silicate-based glass has a viscosity of 20 to 100 poise at a temperature of about 1150 degrees Celsius, that is acceptable for processing in vitrification melters.

6. The silicate-based glass of claim 1, wherein the silicate-based glass has specific electrical conductivity ranging between about 0.1 Ω

<sup>−

1</sup> cm<sup>−

1</sup> to about 0.7 Ω

<sup>−

1</sup> cm<sup>−

1</sup> at a temperature of about 1150 degrees Celsius, that is acceptable for processing in vitrification melters.

7. The silicate-based glass of claim 1, wherein the silicate-based glass meets the Vapor Hydration Test (VHT) requirements of less than about 50 grams per square meter per day, thus meeting current U.S. waste form acceptance criteria.

8. The silicate-based glass of claim 1, wherein the silicate-based glass meets the Product Consistency Test (PCT) requirements of the normalized mass loss of sodium, silicon, and boron being less than about 2 grams per square meter, as defined in the American Society for Testing and Materials (ASTM) C 1285, thus meeting current U.S. waste form acceptance criteria.

9. The silicate-based glass of claim 1, wherein said glass meets the criteria set forth in the U.S. Environmental Protection Agency (EPA) Toxicity Characteristic Leach Test Procedure (TCLP) (SW-846 Method 1311).

10. A silicate-based glass comprising:

rock-forming components selected from the group consisting of SiO₂, Al₂O₃, ZrO₂, alkaline earth oxides, alkaline oxides and mixtures thereof; and

glass-forming components selected from the group consisting of SiO₂, Al₂O₃, ZrO₂, B₂O₃, P₂O₅, TiO₂, Li₂O, F, alkaline earth oxides, alkaline oxides and mixtures thereof;

said silicate-based glass consisting essentially of;

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O), including alkaline oxides, and divalent cation oxides (RO), including alkaline earth oxides;

about 1 part in weight percent of trivalent cation oxides (R₂O₃), including aluminum and ferric oxide;

about 1 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂), including silicon, zirconium and titanium, and pentavalent cation oxides (R₂O₅), including phosphorus oxide; and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

11. The silicate-based glass of claim 10, wherein the ratio between the rock-forming components of the glass formed, approximates the ratio between the main components of natural high alkaline ultrabasic rock.

12. The silicate-based glass of claim 11, wherein the rock-forming components of the said silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O) and divalent cation oxides (RO);

about 1 part in weight percent of trivalent cation oxides (R₂O₃);

about 2 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂) and pentavalent cation oxides (R₂O₅); and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

13. The silicate-based glass of claim 11, wherein the rock-forming components of the silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O), including alkaline oxides, and divalent cation oxides (RO), including alkaline earth oxides;

about 1 part in weight percent of trivalent cation oxides (R₂O₃), including aluminum and ferric oxide;

about 2 to about 3 parts in weight percent of a combination of tetravalent cation oxides (RO₂), and pentavalent cation oxides (R₂O₅), including and phosphorus oxide;

wherein said tetravalent cations comprise silicon, zirconium and titanium, and

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

14. The silicate-based glass of claim 10, wherein the silicate-based glass has a viscosity of 20 to 100 poise at a temperature of about 1150 degrees Celsius, that is acceptable for processing in vitrification melters.

15. The silicate-based glass of claim 10, wherein the silicate-based glass has specific electrical conductivity ranging between about 0.1 Ω

<sup>−

1</sup> cm<sup>−

1</sup> to about 0.7 Ω

<sup>−

1</sup> cm<sup>−

1</sup> at a temperature of about 1150 degrees Celsius, that is acceptable for processing in vitrification melters.

16. The silicate-based glass of claim 10, wherein the silicate-based glass meets the Vapor Hydration Test (VHT) requirements of less than about 50 grams per square meter per day, thus meeting current U.S. waste fog n acceptance criteria.

17. The silicate-based glass of claim 10, wherein the silicate-based glass meets the Product Consistency Test (PCT) requirements of the normalized mass loss of sodium, silicon, and boron being less than about 2 grams per square meter, as defined in the American Society for Testing and Materials (ASTM) C 1285, thus meeting current U.S. waste form acceptance criteria.

18. The silicate-based glass of claim 10, wherein said glass meets the criteria of the U.S. Environmental Protection Agency (EPA) Toxicity Characteristic Leach Test Procedure (TCLP) (SW-846 Method 1311).

19. A silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O) and divalent cation oxides (RO);

about 1 part in weight percent of trivalent cation oxides (R₂O₃);

about 1 to about 2 parts in weight percent of a combination of tetravalent cation oxides (RO₂) and pentavalent cation oxides (R₂O₅);

wherein Na₂O is present in an amount greater than 23 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent;

insuring that the melted glass with integrated waste meets the Vapor Hydration Test (VHT) requirements of less than about 50 grams per square meter per day;

insuring that the melted glass with integrated waste meets the Product Consistency Test (PCT) requirements wherein the silicate-based glass meets the Product Consistency Test (PCT) requirements of the normalized mass loss of sodium, silicon, and boron being less than about 2 grams per square meter, as defined in the American Society for Testing and Materials (ASTM) C 1285; and

wherein said glass meets the criteria of the U.S. Environmental Protection Agency (EPA) Toxicity Characteristic Leach Test Procedure (TCLP) (SW-846 Method

     1311).

20. A silicate-based glass consisting essentially of:

about 1.6 to about 2.2 parts in weight percent of a combination of monovalent cation oxides (R₂O) and divalent cation oxides (RO);

about 1 part in weight percent of trivalent cation oxides (R₂O₃);

about 1 to about 2 parts in weight percent of a combination of tetravalent cation oxides (RO₂) and pentavalent cation oxides (R₂O₅); and

wherein Na₂O is present in an amount greater than 24 weight percent, Al₂O₃ is present in an amount greater than about 13 weight percent and less than about 20 weight percent, SiO₂ is present in an amount greater than about 30 weight percent and less than about 48 weight percent, and B₂O₃ and other flux components are present in a total amount greater than about 9 weight percent and less than about 15 weight percent.

21. The silicate-based glass of claim 20, wherein Na₂O is present in an amount greater than 25 weight percent.

22. The silicate-based glass of claim 20, wherein Na₂O is present in an amount greater than 26 weight percent.

23. The silicate-based glass of claim 20, wherein Na₂O is present in an amount greater than 27 weight percent.

24. The silicate-based glass of claim 20, wherein Na₂O is present in an amount greater than 28 weight percent.

25. The silicate-based glass of any of claim 20, wherein Al₂O₃ is present in an amount greater than about 15 weight percent and less than about 20 weight percent.