Structural characterisation of high temperature K-exchanged sodalite

The exchange reaction of Na-sodalite with KC1 was studied by means of high-temperature X-ray powder diffraction, ex-situ and in-situ, up to 800 degrees C. The powder data were fully refined with the Rietveld method and showed that a substantial amount of K enters the structure in the same crystallographic position of Na, causing some Cl ions to be displaced from their position. The paper shows that sodalite is a potentially good matrix for trapping alkaline metal ions from the electrorefining process of nuclear waste and proposes a method to quickly estimate the amount of K in the structure.