[1G14-16] Zeolite Waste Solidification 2

[1G16] Cs immobilization by the heat-treatment of natural mordenite and effects of sodium carbonate addition

*Aono Hiromichi¹, Takahashi Ryuichiroh¹, Itagaki Yoshiteru¹, Erni Johan¹, Naoto Matsue¹ (1. Ehime university)

Keywords:Cs decontamination, Zeolite, Immobilization, Mordenite, Heat treatment

The Cs ion was partially adsorbed (4.0 % in all of the alkali cation sites) on natural mordenite as a simulated decontamination, then heat-treated to immobilize the Cs in the decomposed zeolite. Although the mordenite phase was maintained for the samples even heated at 800 ^oC, a glassy amorphous phase formed due to the decomposition of the mordenite at 900 ^oC. In the case of the non-treated sample, 3.6% Cs ion from all of the adsorbed Cs was eluted by a dissolution test in deionized water for 14 days. The elution ratio of the Cs ion decreased by the heat treatment. The Cs ion did not elute when the sample was heated at 1000 ^oC and higher temperature due to the Cs containment in the glassy phase. Na₂CO₃ powder was mixed with the mordenite for lowing the glass-forming temperature. The mordenite mixed with Na₂CO₃ had a lower melting point and immobilized the Cs at 900 °C. The Cs evaporation during the heating was also depressed by the Na₂CO₃ addition.