Method of making nanostructured glass-ceramic waste forms
View Patent ↗A method of rendering hazardous materials less dangerous comprising trapping the hazardous material in nanopores of a nanoporous composite material, reacting the trapped hazardous material to render it less volatile/soluble, sealing the trapped hazardous material, and vitrifying the nanoporous material containing the less volatile/soluble hazardous material.
1. A method of rendering hazardous materials less dangerous, the method comprising the steps of:
sorbing a gaseous, molecular hazardous material in nanopores of a nanoporous material to form a sorbed, molecular hazardous material;
fixing the sorbed, molecular hazardous material to the nanoporous material by reacting the sorbed, molecular hazardous material with an alkaline reagent or alkaline silicate to convert the sorbed, molecular hazardous material into a sorbed, anionic hazardous material;
mixing the nanoporous material with glass-forming components excluding clay; and
vitrifying the nanoporous material and glass-forming components to form a glass or crystalline matrix containing nanometer precipitates of the hazardous material.
2. The method of claim 1 wherein the nanoporous material comprises mesoporous alumina with pore sizes up to maximum of about 50 nm.
3. The method of claim 1 wherein the nanoporous material comprises derivatives of mesoporous alumina with pore sizes up to maximum of about 50 nm.
4. The method 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 method of claim 1 wherein the nanoporous material comprises one or more glass forming oxides.
6. The method of claim 5 wherein the glass-forming components comprise one or more glass forming oxides 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 method of claim 6 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 method of claim 1 wherein the hazardous material comprises a radionuclide.
9. The method of claim 8 wherein the hazardous material comprises one or multiple hazardous species in the form of gaseous or soluble ions.
10. The method of claim 9 wherein the hazardous species comprise one or both of 129 I and 99 Tc.
11. The method of claim 1 wherein the vitrifying step occurs at a temperature lower than 1100° C.
12. The method of claim 1 wherein the vitrifying step occurs at a temperature between about 750 and 950° C.
13. The method of claim 1 wherein the vitrifying step occurs at a temperature between about 800 and 900° C.
14. The method of claim 1 wherein the vitrifying step occurs at a temperature between about 850 and 950° C.
15. The method of claim 1 additionally comprising conducting leaching tests to choose optimal compositions of matter for durability of the vitrified materials.
16. The method of claim 1 additionally comprising introducing compositions of matter that result in stable crystals.
17. The method of claim 16 wherein said compositions of matter comprise lithium oxide.
18. The method claim 1 wherein the fixing step comprises reacting the hazardous material with an alkaline metal hydroxide or alkaline metal salt.
19. The method of claim 18 wherein the fixing step comprises reacting the hazardous material with alkaline metal hydroxide.
20. The method of claim 1 wherein the fixing step comprises reacting the hazardous material with sodium or potassium silicate.