[3F06-09] Secondary aqueous waste treatment 1

[3F08] Development of solidification techniques with minimised water content for secondary radioactive aqueous wastes in Fukushima

(3)Effects of phosphates on calcium aluminate cement under hydrothermal conditions

Maria Ines Garcia-Lodeiro¹, Yuan Gao¹, Mehul Chavda¹, Keita Irisawa^1,2, Yoshihiro Meguro², *Hajime Kinoshita¹ (1.The University of Sheffield, 2.Japan Atomic Energy Agency)

Keywords:Phosphate cement, Calcium aluminate cement, Hydroxyapatite, Hydrothermal treatment, secondary radioactive aqueous wastes

The present study investigates the effect of phosphates on hydrothermal treatment of CAC system at 60ºC, 105ºC and 180ºC. The treatment of conventional CAC resulted in formation of stable C₃AH₆ and γ-AlOOH. Modification by mono-phosphate appeared to have delayed the hydration and overall reaction of CAC, whereas poly-phosphate appeared to significantly stabilise the amorphous binding phase up to 180^oC. No crystalline phase was observed except hydroxyapatite when poly-phosphate was used.