HOLLANDITE CONTAINING CERAMIC

摘要

The present invention is directed to processes for immobilising radioactive Cs, and compositions containing immobilised radioactive Cs. Specifically there is provided a process for immobilising radioactive Cs comprising: (a) heating together the following to form a melted material: (i) Cs2O; (ii) an oxide of one or more of Ba, K and Rb; (iii) an oxide of one or more of Ni, Co, Mn, Fe, Cr, and Zn; (iv); (v) CaO; and (vi) an oxide of Zr and/or Hf; wherein the amount of Ti is greater than the amount for the formation of hollandite and wherein the relative amounts of (i) to (vi) are capable of forming a hollandite-type phase and at least two other titanate phases; and (b) allowing the melted material of step (a) to cool to form a composition containing the hollandite-type phase and at least two other titanate phases wherein all or substantially all of the Cs is incorporated in the hollandite-type phase. There is also provided a process for immobilising radioactive Cs using hot subsolidus consolidation techniques. Precursors of the above oxides may be used in substitution for or addition to these oxides.