ABSTRACT
The major processes considered that require extensive off-gas treatment are those used for the solidification of the concentrated radioactive process wastes. The separations processes themselves generally require only filtration, along with any concomitant cooling and heating for dehumidification. All off-gas treatment systems are operated under a negative pressure relative to the process equipment and cell pressures. The principle of recovery, materials of construction, and operating parameters for prefilters are similar to those for high-efficiency particulate air filters. The prefilter may have a clean-air resistance as low as 1 cm of water and a dust loading capacity up to 450 g. Fluidized-bed calcination of United States defense wastes has been done at the Idaho Chemical Processing Plant at the Idaho National Engineering Laboratory since 1963. In this process, the acidic high-activity aqueous waste is sprayed through an atomizing nozzle into a fluidized bed of particles that are heated to 400 to 500°C.
