Zirconolite-based glass-ceramics for actinides immobilization: Effects of glass composition and of actinides simulant nature
Published online by Cambridge University Press: 11 February 2011
Zirconolite (CaZrTi2O7) based glass-ceramics, in which the crystalline phase (aimed at preferentially incorporating minor actinides or Pu) is embedded in a durable calcium aluminosilicate glassy matrix, can be envisaged as good waste form candidates. In this study, the effect of parent glass composition – and particularly of TiO2, ZrO2, CaO and Al2O3 amounts -on the microstructure and the structure of the glass-ceramics obtained after controlled devitrification (nucleation + crystal growth) is reported. It clearly appears that the volume percentage of zirconolite crystals and their nucleation rate in the bulk of the glass strongly depends both on (CaO + ZrO2 + TiO2) and Al2O3 amounts in parent glass. Neodymium is mainly used to simulate trivalent minor actinides whereas several samples were also prepared with other lanthanides (Ce, Eu, Gd, Yb) in order to investigate the effect of simulant field strength in glass on the nature and the composition of the crystals formed. The effect of partial or total molar substitution of ZrO2 by HfO2 in parent glass composition was also studied in order to prepare Ca(Zr1-xHfx)Ti2O7 (0 < × ≤ 1) based glass-ceramics which could be interesting in order to minimize criticality problems.
- Research Article
- MRS Online Proceedings Library (OPL) , Volume 757: Symposium II – Scientific Basis for Nuclear Waste Management XXVI , 2002 , II6.8
- Copyright © Materials Research Society 2003