1959•OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information)Requires access
A STUDY OF EQUILIBRIA INVOLVED BETWEEN DAREX OFF-GASES AND SOLUTIONS. Annual Report No. 1 for December 1, 1958 through July 31, 1959
Clyde Orr, M.C. Kordecki, J. K. Gladden, C.T. Young
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Abstract
In the Darex process, aqua regia is used to dissolve the materials of spent reactor fuel elements. For economic reasons, it is desirable to recover the off-gases from the dissolving process, especially the chlorine, in acid solutions that can be recycled in the system. This project was undertaken to develop a method of analyzing the off-gases and to determine their solubility in various concentrations of hydrochloric acid, nitric acid, and aqua regia at several temperatures. Work was concentrated on the development of a precise method for the quantitative analysis of gaseous mixtures oontaining some or all of the following gases: NO, N/sub 2/O, NO/sub 2/(N/sub 2/O/sub 4/), NOCl, HCl, Cl/ sub 2/, and water vapo r. The initial emphasis was placed on gas chromatography, but no combination of columns and conditions was found by which accurate results for all these gases could be obtained. Analyses by spectrophotometric methods appeared at first to be unsatisfaciory because of the masking by NO/sub 2/ and C1/ sub 2/ in the visible and the ultraviolet range, the absorption by water in the infrared region, and the absence of absorption by C1/sub 2/ in the infrared region. Experiments have now shown, however, that water vapormore » does not entirely mask the other components. A complete analysis can be accomplished if, after the gaseous mixture has been scanned with an infrared spectrophotometer, the separation of chlorine is effected by dissolving the mixture in CCl/sub 4/ and shaking it with water. Only the chlorine remains in the CCl/sub 4/ layer and can be analyzed spectrophotometrically in the ultraviolet or visible region. Preliminary experiments of this type have shown how the gases from aqua regia at atmospheric pressure vary vith time. Samples taken 20 minutes after mixing showed the presence of HCl in the gas phase and gave an indication of some water vapor. Samples taken after 70, 120, and 205 minutes did not reveal HCl but gave progressively larger NOCl peaks and showed a yellow color, indicating the presence of chlorine. After 48 hours the sample peaks were essentially the same as those from the 205-minute sample. (auth)« less