Scanning and high-resolution Auger analysis of zirconolite/perovskite surfaces following hydrothermal treatment

Two titanate minerals, zirconolite with perovskite minor phase inclusions, were subjected to hydrothermal chemical attack. The effects of the treatment were investigated with scanning and high-resolution Auger analysis. The results suggest that both mineral surfaces act as substrates for carbonate precipitation. Dissolution was the main mechanism of attack for perovskite, followed by precipitation from solution and growth of TiO2 on the perovskite phase regions. There was also precipitation of calcium as fluoride and phosphate, and growth of these crystallites at random locations on the surface of the two-phase ensemble. The zirconolite phase regions were not affected by the hydrothermal treatment, within the resolution of the present experiment. This work is relevant to the chemical durability of Synroc nuclear waste form. 7pp 8fig