Immobilization of iodine waste forms: A low-sintering temperature with Bi2O3-B2O3-ZnO glass. (January 2021) - Wei, Guilin
Highlights: Iodine loaded waste forms were immobilized by Bi2 O3 –B2 O3 –ZnO glass below 600 °C. AgI peak intensities and amorphous fraction are mainly effect by temperatures. The diffusivity of Bi decrease with decreasing Bi2 O3 concentration. AgI is physically and chemically packed by the vitrified bulk. Abstract: This study mainly investigated the Bi2 O3 -B2 O3 -ZnO ternary glass to immobilize the iodine waste forms under low sintering temperatures (≤600 °C). Based on the results of Molecular Dynamic (MD) code GULP and amorphous fraction, the Bi2 O3 -B2 O3 -ZnO ternary glass with 20 mol% Bi2 O3 to be chosen to immobilize the sliver-coated silica gel with 10 wt%, 20 wt% and 30 wt% iodine loadings (total content of iodine is 8 wt%). The results show that the amorphous fraction are increased with temperature rising and the composition has dominant effect on determining the density results. The specimen with 20 wt% sintered at 600 °C has the highest amorphous fraction as 0.71. The SEM-EDS results reveal that part of iodine had been physically solidified in the form of white spots and the rest chemically solidified in the glassy phase. Our findings demonstrate the potential of Bi2 O3 -B2 O3 -ZnO ternary glass to immobilize iodine waste forms.