The invention relates to methods of vitrifying waste and for lowering the
melting point of glass forming systems by including lithia formers in the
glass forming composition in significant amounts, typically from about
0.16 wt % to about 11 wt %, based on the total glass forming oxides. The
lithia is typically included as a replacement for alkali oxide glass
formers that would normally be present in a particular glass forming
system. Replacement can occur on a mole percent or weight percent basis,
and typically results in a composition wherein lithia forms about 10 wt %
to about 100 wt % of the alkali oxide glass formers present in the
composition. The present invention also relates to the high lithia glass
compositions formed by these methods. The invention is useful for
stabilization of numerous types of waste materials, including aqueous
waste streams, sludge solids, mixtures of aqueous supernate and sludge
solids, combinations of spent filter aids from waste water treatment and
waste sludges, supernate alone, incinerator ash, incinerator offgas
blowdown, or combinations thereof, geological mine tailings and sludges,
asbestos, inorganic filter media, cement waste forms in need of
remediation, spent or partially spent ion exchange resins or zeolites,
contaminated soils, lead paint, etc. The decrease in melting point
achieved by the present invention desirably prevents volatilization of
hazardous or radioactive species during vitrification.
