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Abstract
The exchange rate of uranium isotopes was investigated in a mixed system of natural U(VI) solution and cation exchange resin containing depleted U (IV) and U(IV) ions at various acid concentrations and temperatures. The experiments showed the presence of two isotopie exchange paths: (1) a first exchange process- “U(IV)-U(IV) exchange occurring within the resinous phase”, and (2) second exchange process- “U(IV)-U(IV) exchange between the resinous and solution phases”.
Based on the experimental results, it was found that
| 1. | The exchange rate constant for the first process is very sensitive to hydrogen ion concentration in the resinous phase. | ||||
| 2. | The exchange rate constant for the second process is almost independent of hydrogen ion concentration in the system. | ||||
| 3. | The apparent activation energy is 13.9 kcal/mol for the first process, and 5.84 kcal/mol for the second. | ||||
| 4. | The cation exchange resin used is an ideal material as adsorbent of U (IV), because U(IV) is stable in the resinous phase and complete mixing of U (IV) and U (VI) is prevented by using this system. | ||||