Flocculation improves uptake of 90Sr and 137Cs from radioactive effluents

• Published in: International journal of mineral processing Vol. 79; no. 4; pp. 225 - 234
• Main Authors: Rout, Tapan K., Sengupta, Dilip K., Besra, Laxmidhar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2006
• Subjects: 90Sr and 137Cs uptake; flocculation; Radioactive effluent; Synthetic sludge; Radioactive effluent; Synthetic sludge; 90Sr and 137Cs uptake; flocculation
• ISSN: 0301-7516; 1879-3525
• DOI: 10.1016/j.minpro.2006.03.001

This paper presents the results of investigation on uptake of radioactive species
90Sr and
137Cs present in the liquid effluents from nuclear processing plants. Chemical precipitation process is adopted to remove radioactivity from the effluents with low and intermediate level of activity. In this process, radioactive
90Sr and
137Cs are co-precipitated along with copper ferrocyanide, ferric hydroxide and either calcium phosphate or barium sulphate. These precipitates being fine in size require flocculation for enhanced settling rate in clarifier/thickener. The flocculation by some selected high molecular weight polyacrylamide based polymers has improved the uptake of radioactive metal ions. The adsorption of these radioactive species has been found to increase in the presence of these flocculants thereby improving the decontamination factor (DF). While flocculating the precipitates, there may be some complex formation with Sr
2+/Cs
+, flocculant and the substrate. This has enhanced the uptake of the radioactive metal ions from the liquid component. The plant trials have indicated the improvement of DF value due to flocculation by cationic flocculant.