Cesium Removal from Nonexpandable Illite Clay by Chloride Salt Treatment

• Published in: ACS omega Vol. 6; no. 28; pp. 17923 - 17930
• Main Authors: Kim, Sung-Wook, Kim, Ilgook, Jeon, Min Ku, Park, Chan Woo, Yoon, In-Ho
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.07.2021
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.1c01516

Extracting cesium (Cs) from nonexpandable illite clay is important in the remediation of radioactive Cs-contaminated soil. In this study, we investigated a chloride salt treatment technique for the removal of Cs from illite. Cs-loaded illite samples with initial Cs concentrations of 2430 and 690 ppm were treated using a NaCl–MgCl2–CaCl2 ternary salt system at 400–850 °C under ambient pressure to suppress Cs loss by vaporization. As a result of the treatment at 850 °C, wherein the salt was in a molten state, the Cs concentration was reduced by 99.5% (to 11.6 ppm) in the first sample and by 99.4% (to 3.86 ppm) in the second sample. Cs removal was achieved for these two samples even in a solid-state reaction at 400 °C, with reductions of 83.3% (407 ppm) and 73.3% (184 ppm), respectively. CsCl was formed by the reaction and remained stable in the salt. The incorporation of cations from the salt (mainly Mg2+) to illite induced structural evolution forming an indialite phase to expel Cs from the clay samples.