Interaction between Synroc-C and pure water or Boom clay

We investigated the interaction between Synroc-C and deionized water or Boom clay disposal media. We used powdered Synroc-C to achieve high SA/V (surface area to volume) conditions (100, 1000, 10000 m^-1). The temperature was 90°C. Reaction progress up to 10⁺⁶ days/m was reached. We conclude that dissolution in DW is mainly controlled by initial ion exchange followed by matrix dissolution. In both Boom clay media (a 500 g/l and a 2000 g/l clay/claywater mixture) matrix dissolution is dominating. The depletion depth of the main Synroc constituent Ti is below 250 nm in the clay media, and below 2 nm in DW after 110 days corrosion at 100 m^-1. The corrosion rates are very small, though we cannot present meaningful values. The effect of Boom clay is mainly to increase the solubility of Ti, Zr and the rare earths in solution.