Immobilization of iodine waste via iodosodalite through subcritical hydrothermal method

Abstract

In this study, iodosodalite was successfully synthesized through subcritical hydrothermal synthesis and sintering, achieving lower sintering temperatures and reaction times compared to traditional methods, with the hydrothermal reaction lasting 1 h and the sintering temperature set at 600 °C. A series of tests were conducted to characterize the microstructure and chemical state of the material, as well as to analyze the conversion process between analcime and iodosodalite, revealing that analcime transforms into iodosodalite at sintering temperatures around 360–370 °C. The synthesized samples exhibited an even distribution of elements, and it was observed that higher hydrothermal temperatures and greater pressures resulted in finer grain sizes. Ultimately, the leaching rate of the synthesized iodosodalite was measured at 0.4 × 10⁻³ gm⁻² d⁻¹ on the seventh day.