Retention of Radionuclides in Halite and Anhydrite

The interaction between a series of radionuclides, comprising **1**3**4Cs** plus , **8**5Sr**2** plus , **6**0Co**2** plus , **1**5**4Eu**3** plus , **2**4**1Am**3** plus , and **9**9Tc (as TcO//4** minus ) and halite (NaCl) and anhydrite (CaSO//4), respectively, has been investigated. It appears that europium and americium as chloro-complexes MCl//2** plus (M equals Eu, Am) interact with the halite surface apparently forming solid europium/americium chloride MCl//3) moieties, which are desorbed only with difficulty.

Batch-type experiments revealed distribution coefficients in the order of 20 and 75 for europium and americium, respectively. Impuritites in the halite, such as hematite or anhydrite strongly increase the sorption efficiency. In these cases also cobalt, and to a minor extent cesium and strontium, was found to be sorbed.

Anhydrite was found to sorb all metal cations studied. The sorption efficiency was found to be dependent the sodium chloride solution. Typically, the highest sorption efficiency for anhydrite was found at intermediary sodium chloride concentration levels (3-5 M).