Aqueous waste vitrification process and apparatus

Claim 1

A process for the treatment of an aqueous waste stream of nonradioactive waste containing at least one inorganic compound comprising a hazardous metal cation capable of forming an oxide upon thermal treatment, wherein said oxide is a glass former, glass intermediate, or glass modifier, said process comprising: (a) introducing said waste stream into a thermal treatment zone; (b) heating said inorganic compound in said thermal treatment zone to convert said compound to the corresponding inorganic oxide and form a melt solution while vaporizing volatile components to form an off-gas; (c) scrubbing said off-gas to provide a ventable flue gas and a liquid condensate; and (d) removing said melt solution from said thermal treatment zone and cooling said solution to form a nonhazardous glass encapsulating the hazardous metal cation.

Claim 20

An apparatus for the treatment of an aqueous waste stream of nonradioactive hazardous waste containing at least one inorganic compound capable of forming an oxide upon thermal treatment, said apparatus comprising: (a) a means for mixing tne waste stream with a material selected from the group consisting of a glass former, a glass intermediate, a glass modifier, and mixtures thereof to form a combined stream; (b) a means for heating said combined stream to form a melt phase with a crust phase thereon, wherein said oxide is concentrated in said melt phase and said melt phase is of a higher temperature than said crust phase, and wherein volatiles are being evolved from said phases; (c) a means for transferring said combined stream from said mixing means to said heating means; (d) a scrubbing means adapted to receive said volatiles from said heating means and scrub said volatiles with a caustic solution to form a condensate which is recycled to said heating means and a flue gas which is vented from said scrubbing means; (e) a means for providing said caustic solution to said scrubbing means; (f) a condensing means for receiving said flue gas from said scrubbing means and forming a condensate and a vent gas; and (g) a means for receiving the melt from said heating means and cooling said melt to form solid shapes.

Claim 21

An apparatus for the treatment of an aqueous waste stream of nonradioactive hazardous waste containing at least one inorganic compound capable of forming an oxide upon thermal treatment, said apparatus comprising: (a) a means for mixing tne waste stream with a material selected from the group consisting of a glass former, a glass intermediate, a glass modifier, and mixtures thereof to form a combined stream; (b) a means for heating said combined stream to form a melt phase with a crust phase thereon, wherein said oxide is concentrated in said melt phase and said melt phase is of a higher temperature than said crust phase, and wherein volatiles are being evolved from said phases; (c) a means for transferring said combined stream from said mixing means to said heating means; (d) a scrubbing means adapted to receive said volatiles from said heating means and scrub said volatiles with a caustic solution to form a condensate which is recycled to said heating means and a flue gas which is vented from said scrubbing means; (e) a means for providing said caustic solution to said scrubbing means; (f) a condensing means for receiving said flue gas from said scrubbing means and forming a condensate and a vent gas; and (g) a means for receiving the melt from said heating means and cooling said melt to form solid shapes.