Development and testing of a cobalt dicarbollide based solvent extraction process for the separation of cesium and strontium from acidic tank waste

A fission product solvent extraction technology for the simultaneous extraction of Cs and Sr from acidic tank waste has been developed as a collaborative effort of the Idaho National Engineering and Environmental Laboratory (INEEL) and the Khlopin Radium Institute in St. Petersburg, Russia. The process is being developed as a potential method for treating the current five million liter inventory of acidic tank waste stored at the INEEL. The fission product extraction process is based on an immiscible organic phase comprised of chlorinated cobalt dicarbollide (CCD, Cs extractant) and polyethylene glycol (PEG, Sr extractant) dissolved in a poly-fluorinated sulfone diluent. Batch contact experiments and preliminary flowsheet testing were used to define potential solvent composition and flowsheet configuration. This information was used to specify an initial flowsheet for countercurrent testing with simulated tank waste using a 3.3-cm diameter centrifugal contactor pilot plant at the INEEL. The initial extrac...