Method of making nanostructured glass-ceramic waste forms
View Patent ↗A waste form for and a method of rendering hazardous materials less dangerous is disclosed that includes fixing the hazardous material in nanopores of a nanoporous material, reacting the trapped hazardous material to render it less volatile/soluble, and vitrifying the nanoporous material containing the less volatile/soluble hazardous material.
1. A waste form formed by a method comprising the steps of:
sorbing a hazardous radioactive material in nanopores of a nanoporous material;
fixing the sorbed hazardous radioactive material with an alkaline reagent or alkaline silicate to render it less volatile/soluble by converting the sorbed hazardous material into a sorbed, anionic hazardous radioactive material;
mixing the nanoporous material with a glass-forming component; and
vitrifying the mixed nanoporous material and glass-forming component to form the waste form;
wherein the waste form comprises nanometer precipitates comprising the hazardous radioactive material; and
wherein the waste form excludes clay.
2. The waste form of claim 1 wherein the nanoporous material comprises alumina with pore sizes up to maximum of about 50 nm.
3. The waste form of claim 1 wherein the nanoporous material comprises derivatives of mesoporous alumina with pore sizes up to maximum of about 50 nm.
4. The waste form of claim 3 wherein the derivatives comprise one or more oxides of transition metals selected from the group consisting of silver (Ag), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn), cobalt (Co), zirconium (Zr), and bismuth (Bi).
5. The waste form of claim 1 wherein the glass-forming component comprises one or more glass-forming oxides.
6. The waste form of claim 5 wherein the one or more glass forming oxides are selected from the group consisting of SiO 2 , Na 2 O, K 2 O, CaO, MgO, B 2 O 3 , Li 2 O, and P 2 O 5 .
7. The waste form of claim 5 wherein the one or more glass forming oxides are in percentages by weight about 0-2% Al 2 O 3 , 12-15% B 2 O 3 , 7-9% Li 2 O, 7-9% Na 2 O, and 68-72% SiO 2 .
8. The waste form of claim 1 wherein the hazardous radioactive material comprises one or more gaseous or soluble ions.
9. The waste form of claim 1 wherein the hazardous radioactive material is selected from the group consisting of 129 I and 99 Tc.
10. The waste form of claim 1 wherein the vitrifying step occurs at a temperature lower than 1100 ° C.
11. The waste form of claim 1 wherein the vitrifying step occurs at a temperature between about 75 ° C. and about 950 ° C.
12. The waste form of claim 1 wherein the vitrifying step occurs at a temperature between about 800 ° C. and about 900 ° C.
13. The waste form of claim 1 wherein the vitrifying step occurs at a temperature between about 850 ° C. and about 950 ° C.
14. The waste form of claim 1 further comprising one or more components that stabilize the nanometer precipitates in stable crystals.
15. The waste form of claim 14 wherein the one or more components comprise lithium oxide.
16. The waste form claim 1 wherein the fixing step comprises reacting the hazardous radioactive material with an alkaline reagent.
17. The waste form of claim 1 wherein the fixing step comprises reacting the hazardous radioactive material with alkaline metal hydroxide.
18. The waste form of claim 1 wherein the fixing step comprises reacting the hazardous radioactive material with sodium or potassium silicate.
19. The waste form of claim 1 wherein the hazardous radioactive material comprises one or multiple hazardous species.
20. The waste form of claim 19 wherein the one or more hazardous radioactive species comprise one or both of 129 I and 99 Tc.