Uptake of Palladium Using Liquid Emulsion Membrane Technique

Abstract

The waste stream generated at the reprocessing facility (first cycle raffinate-Hi level waste) contains Palladium as one of the fission products. The recovery of Palladium from the waste stream reduces the activity burden and lends its use for catalytic applications. This paper deals with its recovery from the waste stream generated at various stages of nuclear fuel cycle using liquid emulsion membrane technique. Complexants chosen were based on the chelating ability with metal ions with high stability constant in the waste stream. Complexants 8-hydroxy quinoline, Thio salicylic acid, dithiazone, cupferron, 1-Niroso-2-naphthol, Quinalizarin were chosen as complexants. The effect of surfactant concentration, complexant concentration, agitating speed, and emulsifcation time on the emulsion stability have been studied. Treat ratio, the ratio of the emulsion phase to the external phase and the impeller speed on the removal of Palladium have been studied. Results show that stable emulsion could be prepared by using 1.5 ml of surfactant span 80 in 50 ml emulsion, with impeller speed 3000 RPM, for duration of 20 minutes using complexants of strength of 70-200 moles/m 3. Effective recovery of Pd could be achieved by using strippant of pH 1-3.7 in the emulsion phase at 250-300 RPM of impeller speed.