Self-Propagating High-Temperature Synthesis for Immobilization of Simulated Radioactive Sandy Soil Waste

The immobilization of simulated radioactive sandy soil waste by using self-propagating high-temperature synthesis (SHS) was investigated. The products were characterized by density, X-ray diffraction, and scanning electron microscope. The leaching rate of tracer element was measured by the method of PCT (product consistency test). The SHS immobilization typically results in products containing amorphous phase and crystalline phase. The volume density of the final product is over 3.0g/cm3. The tracer element Ce in the final product mainly forms crystalline phase of CeAl11O18 and Ce2SiO5 when the amount of CeO2 in the raw material is large than 1%. The leaching rate of Ce for 28 days is about 10-5 g•m-2•d-1，which is much lower than that of the borosilicate glass solid form. the leaching rates of Ca, Si, Al and Fe during 28 days are about 10-3～10-4 g•m-2•d-1