Hydrothermal synthesis of rock to immobilise nuclide Cs

To deal with the soil polluted by radioactive nuclide Cs like that in Fukushima, Japan. As pollucite evolves via analcime into clay mineral finally in nature, the analcime and final pollucite should be synthesized from clay minerals. A hydrothermal technology has been applied to synthesize rock to immobilize radioactive Cs within soil for this purpose. The results showed that Gmelinite seemed to precipitate at lower Na/Al molar ratio of starting materials easily, while analcime formed at higher Na/Al. Pollucite was synthesized with meta-kaolin and different Cs compounds (CsOH or CsCl), and more pollucite was formed by CsOH addition, while Cs located inside structure of analcime (solid solution) with addition of CsCl. The pollucite morphology added by CsOH exhibited nano-scale spheroidal aggregate, while analcime gave morphology of triakioctahedron and hexagonal prism.