Metal emissions from joule-heated vitrification systems

This paper present the emissions of a pilot-plant, joule-heated, slurry-fed vitrification system for three surrogate mixed-waste sludges from DOE facilities. The sludges simulated were WETF, Rocky Flats precipitate, and LANL TA-50 sludge. They were vitrified in a high-temperature, refractory lined, slurry-fed melter. Each demonstration produced a durable glass that had low leaching in both the TCLP and PCT tests. Due to the glass compositions chosen for the demonstration, all three glasses had a tendency to devitrify if cooled slowly. The total particulate concentrations and melter decontamination factors were determined for selected elements. The average decontamination factors were less than 10 for cadmium and lead in all three demonstrations. The decontamination factors and were less than 20 for chromium and 40 silver in the Rocky Flats demonstration. Decontamination factors were above 100 for the other metals in the demonstrations. The average melter decontamination factors presented in this paper are from tests on the emissions from one pilot-scale melter in a series of demonstrations using slurry feed. These factors allow the estimation of the input to air pollution control equipment necessary for operation of such a system in full-scale operation with radioactive or mixed wastes