Formation of plutonium (IV) silicate species in very alkaline reactive media

The formation of stable plutonium (IV) silicate colloidal suspension has been identified in very alkaline reactive media (pH ≥ 13). XAS measurements allowed to observe that these species exhibit a structure similar to those reported at (IV) oxidation state, like for thorium, uranium and neptunium silicates counterparts. These colloids can be stabilized in aqueous solution at concentrations around 10 2 mol·L 1 and successive filtration process allowed to evaluate that most of these silicates had a size ranging between 3 and 6 nm. This result may bring new outlooks on the behavior of plutonium in silicate ions rich reactive media