Identification of glass compositions suitable for disposal of waste reactive metal

This study was conducted in support of a project to convert waste sodium to a form that is amenable to easy disposal in ordinary landfills. This waste sodium will be from reactor and other operations at the US Department of Energy and will contain small amounts of radioactive species that must not be released to the environment in an uncontrolled manner. The sodium will be converted into a glass that will contain and isolate the radionuclides present in it. This study was conducted to define acceptable glass compositions that (1) are resistant to leaching of sodium by groundwater and rainwater, (2) contain a relatively large proportion of sodium so that unreasonably large volumes of the glass for disposal will not be produced, and (3) are conveniently prepared from the waste sodium. For this purpose, glass samples containing varying amounts of the oxides of sodium, calcium, boron, aluminum, and silicon were prepared in the laboratory. The samples were subjected to the accelerated MCC-1 test to determine resistance to leaching by water at 60/degree/C. Soda-silica glasses were observed to dissolve in the water rather quickly. Addition of the other ingredients was found to impart significant leach resistance to the glasses. Among themore » high-Na/sub 2/O glasses, those containing alumina (3% Al/sub 2/O/sub 3/-10% CaO-30% Na/sub 2/O and 6% Al/sub 2/O/sub 3/-10% B/sub 2/O/sub 3/-30% Na/sub 2/O) were found to be most resistant to leaching. Lowering the Na/sub 2/O content to 20% made these glasses even more leach resistant. 8 refs., 6 figs., 2 tabs.« less