Behaviour of lanthanide aluminosilicate glass in water: Preliminary results

Lanthanide aluminosilicate glasses have been developed for their high mecha nical properties. Nevertheless, little is known about their chemical durabi lity and the role of rare-earth elements on the dissolution mechanisms of s uch glasses, This type of glass appears to be a suitable complement waste f orms of borosilicate glass for the specific immobilisation of trivalent act inides. The first part of this paper deals with the synthesis and the chara cterisation of glasses in the system SiO2-Al2O3-Y2O3-Ln(2)O(3) (with Ln = L a or Ce) and the second part with the study of their leachability in deioni sed water using a reflux column at 100 degreesC. Hydrated glass surfaces ha ve been examined with scanning electron microscopy coupled with X-ray micro analysis and nuclear microanalysis. Leachates have been characterised by us ing ICP-MS and UV-visible spectrophotometry. After leaching, the formation of a surface layer slightly depleted in Si and Al and containing Y and La h ydroxicarbonates and hydroxides is discussed. (C) 2001 Elsevier Science B.V . All rights reserved.