Strontium removal from caustic carbonate waste solutions using carrier coprecipitation

A carrier coprecipitation procedure has been developed for the radioactive strontium from caustic liquid low-level waste (LLLW) generated at Oak Ridge National Laboratory. The from caustic liquid low-level waste (LLLW) generated at Oak two-step treatment process involves the addition of normal Sr (as SrCl2) to the waste matrix, which is composed primarily of 0.3 M NAOH and 0.6 M Na2CO3. The active Sr equilibrates with the normal Sr carrier and coprecipitates as SrCO3 at pH 13. A liquid/solid separation is made before the pH of the supernate is reduced to pH 8 with sulfuric acid. During the neutralization step, the aluminum in the waste precipitates as Al(OH)3 Further Sr decontamination is achieved as traces of active Sr sorb to the Al(OH)3 that precipitates during the neutralization step. A final liquid/solid separation is made at pH 8 to remove the sorbed active Sr