Volatilization of cesium-137 from soil with chloride amendments during heating and vitrification

During vitrification of soil and soil:limestone mixtures, significant volatilization (> 10%) of the radioisotope 137Cs occurred particularly in the presence of small amounts (<5%) of chloride-containing species including sodium chloride, calcium chloride, hydrochloric acid, and poly-(vinyl chloride). Sodium chloride was found to be the most effective, resulting in volatilization of >99% of the 137Cs by repeated amendment and treatment at 1000 degree C. Amendment with sodium borate and subsequent heating to 1200 degree C also stimulated significant volatilization of 137Cs. However, amendments up to 10% of other chemicals including carbonates, nitrates, phosphates, sulfates, fluorides, polystyrene, graphite, stainless steels, iron, zinc oxide, and antimony oxide did not increase 137Cs volatilization compared to unamended samples. The majority of the chloride-induced volatilization occurred between 800 and 1000 degree C for sodium chloride-amended samples of both soil and soil:limestone mixtures. Thus, an effective and potentially efficient soil decontamination technique for 137Cs has been identified. 17 refs., 8 figs., 3 tabs