ZIRCONIUM REMOVAL FROM URANIUM HYDROGEN CARBONATE SOLUTIONS BY ADSORPTION ON MANGANESE-DIOXIDE

In order to determine the best conditions for removing Zr-95 from uran ium/hydrogen carbonate solutions, the adsorption behavior of fission p roduct Zr-95 on hydrated MnO2 as a function of HCO3- ion molarity has been studied both in the presence and absence of uranium. Batch experi ments showed that the maximum Zr-95 uptake occurred at low HCO3- conce ntration, both in uranium-free and uranium (at a constant molarity of 0.02) containing solutions, the relative Zr-95 uptake being lower when uranium was present in the solution. Conversely, when the HCO3- conce ntration augmented beyond 0.10 M, the Zr-95 uptake was higher for the uranium containing solution. Concerning this last case, the maximum Zr -95 uptake was found at a 0.06 M HCO3- concentration. However at this HCO3- concentration,uranium was observed to precipitate and thus, a HC O3- concentration of 0.12 M was chosen to perform the dynamic Zr-95 re moval by MnO2 from uranium/hydrogen carbonate solutions. Under these c onditions, the Zr-95 removal reached 99%.