Americium ions recovery

Sekine et al. [27] used a-spectrometry to determine plutonium (and americium) in soil. The chemical recovery of plutonium was 51-99% and averaged 81%, while for americium the recovery was 60-70%. The method is coupled with the liquid-liquid extraction stage, taking about two days less than the ion exchange method a complete analysis takes about one week. 

Figure 1 shows a simplified flow sheet for plutonium-239 recovery operations at Rocky Flats. Impure plutonium metal is sent through a pyrochemical process, called molten salt extraction (MSE), to remove the elemental impurity americium. The product plutonium metal, if it meets plant purity requirements, is sent to the foundry. Metal that does not meet foundry requirements is processed further, either through an aqueous process using ion exchange, or through a pyrochemical electrorefining process. The waste chloride salt from MSE is... 

Additional work in progress includes optimization of parameters affecting the oxalate precipitation step this includes determination of the chloride concentration required to solubilize lead the oxalate ion concentration required for maximum americium recovery with minimum impurity precipitation precipitate aging and hydrogen ion concentrations that will minimize americium solubility yet maximize impurity solubilization. 

These studies resulted in the proposed solvent extraction recovery process for Am as given in the flowsheet of Figure 14. Solvent clean-up and recycle are included. The Am product stream is to enter the present Am02 production line either before or behind the ion exchange step (Figure 3) depending upon the concentration of Pu in the extracted americium. 

Process studies were also performed on the ion-exchange and precipitation methods for the recovery of plutonium and americium from the aqueous or organic waste discharged from the above mentioned process (31). 

Traditionally, the recovery and purification of americium has utilized primarily aqueous ion-exchange, solvent extraction, and precipitation processes. Departures are represented by the pyrochemical process and distillation of americium metal in high vacuum used at the Rocky Flats plant (Colorado) [333]. 

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