Production of Neptunium Oxide from Impure Solutions by Anion Exchange Followed by Oxalate Precipitation

Abstract

The stabilization of the neptunium solutions stored at the Savannah River Site (SRS) has generated additional recycle solutions that contain a different mix of impurities. A list of expected purities and the known laboratory and production data for purification from those impurities has been accumulated. An evaluation has been performed of the options for modifying the current process to ensure oxide product purity does not significantly change when recycle solutions are processed. This paper discusses the details of the reduction of the major impurities utilizing both known production quality analyses and laboratory flowsheet development data and proposes modifications to the anion wash volumes to remove higher levels of each impurity.

Keywords:

• Anion exchange
• neptunium
• plutonium
• precipitation
• purification
• uranium

ACKNOWLEDGEMENTS

The authors would like to acknowledge Vern Jones and Sheldon Nichols, for their comments on the production analytical results; Jon Duffey for his assistance with the raw data on the uranium washing work, and Major Thompson, SRNL retired, for his helpful advice and consultations.