In this paper, experimental study on static absorption was carried out for Alashan clay rock on Inner Mongolia. To explore the factors which may influence absorption characteristic of U(Ⅵ) on clay rock, including contact time, U(Ⅵ) initial concentration, solid-liquid ratio, pH value, ionic type and ionic concentration. The following results are obtained. The absorption rate of U(Ⅵ) on Alashan clay rock in Inner Mongolia is quite fast with adsorption equilibrium achieved in 24 hours. The optimum adsorption ratio is 1:200, and the optimum adsorption concentration is 160 μg?mL-1.The absorption capacity of clay rock was enlarged with the increasing of pH value. When pH value is at 8, the ability of absorption reaches the best. The absorption capacity of Uranium is largely hindered by Ca2+、CO32- and HCO3-, which have a great effect on the absorption ability of U(Ⅵ). The distribution coefficients of K+、Na+、Cl-、NO3-、SO42- can be changed with the change of ionic concentration, The surface adsorption of U(Ⅵ) on clay rock is dominated by inner-sphere complexation. The studies indicate the adsorption behavior of U(Ⅵ) on clay rock has a great significance on settling high level radioactive waste in China.
