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 Cs-137 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 Cs-137 by repeated amendment and treatment at 1000-degrees-C. Amendment with sodium borate and subsequent heating to 1200-degrees-C also stimulated significant volatilization of Cs-137. 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 Cs-137 volatilization compared to unamended samples. The majority of the chloride-induced volatilization occurred between 800 and 1000-degrees-C for sodium chloride-amended samples of both soil and soil:limestone mixtures. Thus, an effective and potentially efficient soil decontamination technique for Cs-137 has been identified.