RECOVERY OF STRONTIUM AND RARE EARTHS FROM PUREX WASTES BY SOLVENT EXTRACTION

A solvent extraction flowsheet was developed for recovery of strontium- 90 and mixed rare-earth fission products from adjusted Purex 1WW waste solution by di(2-ethylhexyl)phosphoric acid (D2EHPA) in Amsco l25-82 modified with tributyl phosphate (TBP). First cycle feed is prepared by adding tartrate and caustic to the waste solution to complex the iron and adjust the pH. Strontium and rare earths are coextracted with D2EHPA-TBP-Amsco and stripped with nitric acid in the first cycle, and then isolated as concentrated product solutions by processing through additional solvent extraction cycles. Satisfactory product recoveries and physical operation were demonstrated in bench-scale batch and continuous countercurrent tests with simulated, unirradiated, feed solutions. (auth