Removal of iodine species with concentrated nitric acid, (7)

For the Iodox process, which is atrractive for the iodine removal from off-gas stream in nuclear fuel reprocessing, a new iodine treatment process has been examined by laboratory-scale experiment. The process includes the step of stripping iodine from solution by the nitrogen oxide produced from nitric acid with formaldehyde, formic acid or sucrose. (1) As nitric acid is decomposed from azeotropic composition to 12N, about 90% of I2 is evolved from the solution of IO3-. (2) The addition of formaldehyde or formic acid as a decomposing agent lowers the iodine residue in solution to less than 1% with the progressing decomposition of nitric acid to about 2N. (3) With sucrose as a decomposing agent, it takes a few hours to complete the reaction, which results in iodine reflux from a condenser. (J.P.N.)