METAL ANTIMONATES – HIGHLY EFFECTIVE ION EXCHANGERS FORRADIONUCLIDE REMOVAL FROM ACIDIC AND NEUTRAL WASTE SOLUTIONS

摘要

Several metal antimonates MSbO (M = Si, Ti, Mn, Sn) have been studied for the removal ofrnseveral key radionuclides (60Co, 90Sr and 137Cs) from nuclear waste solutions. Special emphasisrnwas the removal of radionuclides from acidic effluents and from effluents of high Ca content.rnSynthesis and initial screening test indicated that increasing the degree of substitution of otherrnmetals (M) for Sb increases the uptake of divalent cations (Sr, Co) in acidic media. Some of thernsynthesised compounds also showed considerable tolerance for Ca ions in Sr removal. Columnrntests with granular silicon antimonate gave very good decontamination factors (DF) for 85Sr (DFrnup to 10000) and 134Cs (DF up to 600) in nitric acid solution (0.1 M) and for 57Co (up to 5000)rn85Sr (up to 3000) in neutral simulated pond water. Precoat tests with manganese antimonaternpowder gave high decontamination factors for 57Co (DF up to 600) in simulated NPP floor drainrnwater. In general, the performance of the metal antimonates was considerably better than that ofrncommercial materials (zeolite, titanate, and silicotitanate) that were tested in parallel forrnreference.