A RAMAN-SPECTROSCOPIC STUDY OF THE INTERACTION OF CESIUM IONS WITH OXYANIONS IN CARBONATE MELTS

The Raman spectra of molten carbonate salts containing salts of other oxyanions including sulfate, molybdate and phosphate, exhibited vibrat ional bands assigned to carbonate and the other oxyanions. Increments of a cesium salt were added to each mixture to obtain varying values o f the cation-dependent parameter log P alpha. The variations of log P alpha with the frequencies of the Raman bands revealed a trend in the sensitivities of the various oxyanions to the cesium content of the me lt that appears to be related to the basicity of the oxyanions. If the interactions that contribute to the observed frequency changes also i nfluence the volatility of cesium in molten carbonates, the results su ggest that addition of oxyanions like sulfate, that are significantly less basic than carbonate, will decrease the cesium volatility. This c onclusion is consistent with recent studies that showed sulfate salts were effective in lowering the volatility of cesium in molten sodium c arbonate at 900 degrees C. (C) 1997 Elsevier Science B.V.