| Abstract Scope |
The hollandite mineral group is one of the most studied as a host for Cs immobilization. In this work, the A site species consisting of Ba and Cs with a wide range of B site dopants including Zn, Ga, Fe, Al and Cr were incorporated into the hollandite structure. The enthalpies of formation of the hollandite phases measured using high temperature oxide melt solution calorimetry were found to be negative, indicating these hollandites are thermodynamically stable with respect to their constituent oxides. Furthermore, the formation enthalpies were more negative and hence more favourable with increased Cs content across a wide range of B site dopants. In addition to formation energy measurements, monolithic and powder-based aqueous leaching tests indicated that the hollandite phase with higher Cs-loading possessed enhanced Cs retention. In parallel, three Cs end member compositions of the tunnel structured hollandite samples (Cs1.33Ga1.33Ti6.67O16, Cs1.33Fe1.33Ti6.67O16, and Cs1.33Zn0.67Ti7.33O16) were synthesized and irradiated beam in order to study effects of B-site dopants on radiation stability. |