Conversion of Hanford salt cake to glass: laboratory studies

Approximately 140 million liters of solid salt cake (mainly NaNO3), produced by evaporation of aged, alkaline high-level wastes, will be stored in underground tanks when the present Hanford Waste Management Program is completed in the early 1980's. These solid wastes can be converted to silicate-based glasses by melting them either at 1200 to 13000C with appropriate amounts of sand and lime (soda-lime formulation) or at 1000 to 11000C with appropriate amounts of Columbia River basalt and B2O3 (basalt formulation). Both formulations yield dense, immobile glasses of low water leachability (10-7 to 10-6 g cm-2 day-1) suitable for terminal storage. The soda-lime formulation is presently preferred over the basalt formulation because it can accommodate more salt cake (50 wt percent versus 30 to 40 wt percent) while yielding a glass whose volume is 10 to 20 percent less than the volume of the salt cake in the melt charge