Immobilization of Simulated ⁹⁰Sr in Spinel Synroc Synthesized From Hydratalcite Precursor

Spinel synroc in which Sr (simulating ⁹⁰Sr) was embedded by using Sr-containing hydrotalcite as the precursor. The optimum conditions of spinel synthesis were determined by X-ray diffraction (XRD), thermogravimetric analysis (TG) and leaching experiments as follows: the calcining temperature 1 100℃, calcining time 4h and maximum Sr loading 0.648%. The mine phase assemblages and micro-structure of spinel synroc were analyzed by XRD and scanning electron microscopy with energy dispersive spectrometer (SEM/EDS). The chemical stability tests were carried out by MCC-1 method and PCT method. The results indicate that the prepared spinel synroc has good physical properties with density of 4.8 g/cm³ and open porosity of 0.07%. Sr is embedded into the crystal lattice of spinel. Under these conditions, the elemental nominalized leach rate of Sr is 5.2×10^-2 g/（m²•d） by PCT method at 90℃, the 7th day. The spinel synroc has a good chemical stability.