Alkali salt-assisted Cs-desorption and crystal growth from a silicate mineral

Hasegawa, Yuri  ; Honda, Mitsunori   ; Suzuki, Shinichi; Yaita, Tsuyoshi

Recycling of radioactive polluted soil has been one the latest issues in environmental restoration. Among minerals in soil, weathered biotite fix Cs strongly. Recently, elimination of Cs accompanied by growth of various kind of crystal from weathered biotite was realized only by heating with alkali salt (NaCl-CaCl). Since some of those crystals are available as a functional material, further understanding of the process of crystal growth is required for selective growth. However, understating the crystal growth is difficult because WB consists of weathered and un-weathered phase. Therefore, in this study, crystal growth form un-weathered biotite was investigated. XRD measurement revealed growth of FeO, Wadalite, and pyroxene were observed from 2 m of biotite, whereas pyroxene was not observed from 75m of biotite. In addition, pyroxene was not observed even with 2m of biotite when NaCl:CaCl=7:3. These result suggest size of biotite and NaCl:CaCl ratio affect selective growth.